WorldWideScience

Sample records for surface spectroscopic characterization

  1. Electrochemical and spectroscopic characterization of surface sol-gel processes.

    Science.gov (United States)

    Chen, Xiaohong; Wilson, George S

    2004-09-28

    (3-Mercaptopropyl)trimethoxysilane (MTS) forms a unique film on a platinum substrate by self-assembly and sol-gel cross-linking. The gelating and drying states of the self-assembled MTS sol-gel films were probed by use of electrochemical and spectroscopic methods. The thiol moiety was the only active group within the sol-gel network. Gold nanoparticles were employed to detect the availability of the thiol group and their interaction further indicated the physicochemical states of the sol-gel inner structure. It was found that the thiol groups in the open porous MTS aerogel matrix were accessible to the gold nanoparticles while thiol groups in the compact MTS xerogel network were not accessible to the gold nanoparticles. The characteristics of the sol-gel matrix change with time because of its own irreversible gelating and drying process. The present work provides direct evidence of gold nanoparticle binding with thiol groups within the sol-gel structures and explains the different permeability of "aerogel" and "xerogel" films of MTS on the basis of electrochemical and spectroscopic results. Two endogenous species, hydrogen peroxide and ascorbic acid, were used to test the permeability of the self-assembled sol-gel film in different states. The MTS xerogel film on the platinum electrode was extremely selective against ascorbic acid while maintaining high sensitivity to hydrogen peroxide in contrast to the relatively high permeability of ascorbic acid in the MTS aerogel film. This study showed the potential of the MTS sol-gel film as a nanoporous material in biosensor development.

  2. Spectroscopic characterization of biological agents using FTIR, normal Raman and surface-enhanced Raman spectroscopies

    Science.gov (United States)

    Luna-Pineda, Tatiana; Soto-Feliciano, Kristina; De La Cruz-Montoya, Edwin; Pacheco Londoño, Leonardo C.; Ríos-Velázquez, Carlos; Hernández-Rivera, Samuel P.

    2007-04-01

    FTIR, Raman spectroscopy and Surface Enhanced Raman Scattering (SERS) requires a minimum of sample allows fast identification of microorganisms. The use of this technique for characterizing the spectroscopic signatures of these agents and their stimulants has recently gained considerable attention due to the fact that these techniques can be easily adapted for standoff detection from considerable distances. The techniques also show high sensitivity and selectivity and offer near real time detection duty cycles. This research focuses in laying the grounds for the spectroscopic differentiation of Staphylococcus spp., Pseudomonas spp., Bacillus spp., Salmonella spp., Enterobacter aerogenes, Proteus mirabilis, Klebsiella pneumoniae, and E. coli, together with identification of their subspecies. In order to achieve the proponed objective, protocols to handle, cultivate and analyze the strains have been developed. Spectroscopic similarities and marked differences have been found for Spontaneous or Normal Raman spectra and for SERS using silver nanoparticles have been found. The use of principal component analysis (PCA), discriminate factor analysis (DFA) and a cluster analysis were used to evaluate the efficacy of identifying potential threat bacterial from their spectra collected on single bacteria. The DFA from the bacteria Raman spectra show a little discrimination between the diverse bacterial species however the results obtained from the SERS demonstrate to be high discrimination technique. The spectroscopic study will be extended to examine the spores produced by selected strains since these are more prone to be used as Biological Warfare Agents due to their increased mobility and possibility of airborne transport. Micro infrared spectroscopy as well as fiber coupled FTIR will also be used as possible sensors of target compounds.

  3. Raman Spectroscopic Characterization of the Feldspars: Implications for Surface Mineral Characterization in Planetary Exploration

    Science.gov (United States)

    Freeman, J. J.; Wang, Alian; Kuebler, K. E.; Haskin, L. A.

    2003-01-01

    The availability in the last decade of improved Raman instrumentation using small, stable, intense lasers, sensitive CCD array detectors, and advanced fast grating systems enabled us to develop the Mars Microbeam Raman Spectrometer (MMRS), a field-portable Raman spectrometer with precision and accuracy capable of identifying minerals and their different compositions. For example, we can determine Mg cation ratios in pyroxenes and olivines to +/-0.1 on the basis of Raman peak positions. Feldspar is another major mineral formed in igneous systems whose characterization is important for determining rock petrogenesis and alteration. From their Raman spectral pattern, feldspars can be readily distinguished from ortho- and chain-silicates and from other tecto-silicates such as quartz and zeolites. We show here how well Raman spectral analysis can distinguish among members within the feldspar group.

  4. Synthesis, structural characterization, Hirshfeld surface analysis and spectroscopic studies of cadmium (II) chloride complex with 4-hydroxy-1-methylpiperidine

    Science.gov (United States)

    Soudani, S.; Ferretti, V.; Jelsch, C.; Lefebvre, F.; Nasr, C. Ben

    2016-05-01

    The chemical preparation, crystal structure, Hirshfeld surface analysis and spectroscopic characterization of the novel cadmium (II) 4-hydroxy-1-methylpiperidine complex, Cd4Cl10(C6H14NO)2·2H2O, have been reported. The atomic arrangement can be described as built up by an anionic framework, formed by edge sharing CdCl6 and CdCl5O octahedral linear chains spreading along the a-axis. These chains are interconnected by water molecules via O-H⋯Cl and O-H⋯O hydrogen bonds to form layers parallel to (011) plane. The organic cations are inserted between layers through C-H⋯Cl hydrogen bonds. Investigation of intermolecular interactions and crystal packing via Hirshfeld surface analysis reveals that the HC⋯Cl and HC⋯HC intermolecular interactions are the most abundant contacts of the organic cation in the crystal packing. The statistical analysis of crystal contacts reveals the driving forces in the packing formation. The 13C and 15N CP-MAS NMR spectra are in agreement with the X-ray structure. The vibrational absorption bands were identified by infrared spectroscopy. DFT calculations allowed the attribution of the NMR peaks and of the IR bands.

  5. Synthesis, structural characterization, Hirshfeld surface analysis and spectroscopic studies of cadmium (II) chloride complex with 4-hydroxy-1-methylpiperidine

    Energy Technology Data Exchange (ETDEWEB)

    Soudani, S. [Université de Carthage, Laboratoire de Chimie des Matériaux, Faculté des Sciences de Bizerte, 7021 Zarzouna (Tunisia); Ferretti, V. [Department of Chemical and Pharmaceutical Sciences and Center for Structural Diffractometry, via Fossato di Mortara 17, I-44121 Ferrara (Italy); Jelsch, C. [CRM2, CNRS, Institut Jean Barriol, Université de Lorraine, Vandoeuvre les Nancy CEDEX (France); Lefebvre, F. [Laboratoire de Chimie Organométallique de Surface (LCOMS), Ecole Supérieure de Chimie Physique Electronique, 69626 Villeurbanne Cedex (France); Nasr, C. Ben, E-mail: cherif_bennasr@yahoo.fr [Université de Carthage, Laboratoire de Chimie des Matériaux, Faculté des Sciences de Bizerte, 7021 Zarzouna (Tunisia)

    2016-05-15

    The chemical preparation, crystal structure, Hirshfeld surface analysis and spectroscopic characterization of the novel cadmium (II) 4-hydroxy-1-methylpiperidine complex, Cd{sub 4}Cl{sub 10}(C{sub 6}H{sub 14}NO){sub 2}·2H{sub 2}O, have been reported. The atomic arrangement can be described as built up by an anionic framework, formed by edge sharing CdCl{sub 6} and CdCl{sub 5}O octahedral linear chains spreading along the a-axis. These chains are interconnected by water molecules via O–H⋯Cl and O–H⋯O hydrogen bonds to form layers parallel to (011) plane. The organic cations are inserted between layers through C–H⋯Cl hydrogen bonds. Investigation of intermolecular interactions and crystal packing via Hirshfeld surface analysis reveals that the H{sub C}⋯Cl and H{sub C}⋯H{sub C} intermolecular interactions are the most abundant contacts of the organic cation in the crystal packing. The statistical analysis of crystal contacts reveals the driving forces in the packing formation. The {sup 13}C and {sup 15}N CP-MAS NMR spectra are in agreement with the X-ray structure. The vibrational absorption bands were identified by infrared spectroscopy. DFT calculations allowed the attribution of the NMR peaks and of the IR bands.

  6. Optical properties and surface characterization of pulsed laser-deposited Cu{sub 2}ZnSnS{sub 4} by spectroscopic ellipsometry

    Energy Technology Data Exchange (ETDEWEB)

    Crovetto, Andrea, E-mail: ancro@nanotech.dtu.dk [DTU Nanotech, Technical University of Denmark, DK-2800 Kgs. Lyngby (Denmark); Cazzaniga, Andrea; Ettlinger, Rebecca B.; Schou, Jørgen [DTU Fotonik, Technical University of Denmark, DK-4000 Roskilde (Denmark); Hansen, Ole [DTU Nanotech, Technical University of Denmark, DK-2800 Kgs. Lyngby (Denmark); CINF, Center for Individual Nanoparticle Functionality, Technical University of Denmark, DK-2800 Kgs. Lyngby (Denmark)

    2015-05-01

    Cu{sub 2}ZnSnS{sub 4} films prepared by pulsed laser deposition at different temperatures are characterized by spectroscopic ellipsometry. The focus is on confirming results from direct measurement techniques, by finding appropriate models of the surface overlayer for data fitting, and extracting the dielectric function of the films. It is found that the surface overlayer changes with film thickness and deposition temperature. Adopting different ellipsometry measurements and modeling strategies for each film, dielectric functions are extracted and compared. As the deposition temperature is increased, the dielectric functions exhibit additional critical points related to optical transitions in the material other than absorption across the fundamental band gap. In the case of a thin film < 200 nm thick, surface features observed by scanning electron microscopy and atomic force microscopy are accurately reproduced by ellipsometry data fitting. - Highlights: • Inhomogeneous Cu{sub 2}ZnSnS{sub 4} films are prepared by pulsed laser deposition. • The film surface includes secondary phases and topographic structures. • We model a film surface layer that fits ellipsometry data. • Ellipsometry data fits confirm results from direct measurement techniques. • We obtain the dielectric function of inhomogeneous Cu{sub 2}ZnSnS{sub 4} films.

  7. Vibrational spectroscopic characterization of fluoroquinolones

    Science.gov (United States)

    Neugebauer, U.; Szeghalmi, A.; Schmitt, M.; Kiefer, W.; Popp, J.; Holzgrabe, U.

    2005-05-01

    Quinolones are important gyrase inhibitors. Even though they are used as active agents in many antibiotics, the detailed mechanism of action on a molecular level is so far not known. It is of greatest interest to shed light on this drug-target interaction to provide useful information in the fight against growing resistances and obtain new insights for the development of new powerful drugs. To reach this goal, on a first step it is essential to understand the structural characteristics of the drugs and the effects that are caused by the environment in detail. In this work we report on Raman spectroscopical investigations of a variety of gyrase inhibitors (nalidixic acid, oxolinic acid, cinoxacin, flumequine, norfloxacin, ciprofloxacin, lomefloxacin, ofloxacin, enoxacin, sarafloxacin and moxifloxacin) by means of micro-Raman spectroscopy excited with various excitation wavelengths, both in the off-resonance region (532, 633, 830 and 1064 nm) and in the resonance region (resonance Raman spectroscopy at 244, 257 and 275 nm). Furthermore DFT calculations were performed to assign the vibrational modes, as well as for an identification of intramolecular hydrogen bonding motifs. The effect of small changes in the drug environment was studied by adding successively small amounts of water until physiological low concentrations of the drugs in aqueous solution were obtained. At these low concentrations resonance Raman spectroscopy proved to be a useful and sensitive technique. Supplementary information was obtained from IR and UV/vis spectroscopy.

  8. Structural and spectroscopic studies of surfaces

    CERN Document Server

    Laitenberger, P

    1996-01-01

    and on a 10ML thick Ar spacer layer, a remarkable substrate dependence is revealed. A new STM-based technique for fabricating simple metal-structures with dimensions in the 10-100nm regime which are partially electrically isolated from their environment was developed in collaboration with Dr. L. A. Silva. This technique employs the STM tip as a mechanical nanofabrication tool to machine gaps into a thin metallic film deposited on an insulating substrate, which laterally confine and electrically isolate the desired metal regions. Several metal structures, such as nanoscale wires and pads, were successfully created. Finally, the conceptual basis and present stage of construction of a new surface analytical tool, the Scanning Probe Energy Loss Spectrometer (SPELS), is discussed. The SPELS offers the exciting prospect of collecting structural as well as spectroscopic information with a spatial resolution of a few nanometres. Once successfully developed, it will be ideally suited for spectroscopic studies of nanos...

  9. Grafting of functionalized [Fe(III)(salten)] complexes to Au(111) surfaces via thiolate groups: surface spectroscopic characterization and comparison of different linker designs.

    Science.gov (United States)

    Jacob, Hanne; Kathirvel, Ketheeswari; Petersen, Finn; Strunskus, Thomas; Bannwarth, Alexander; Meyer, Sven; Tuczek, Felix

    2013-07-01

    Functionalization of surfaces with spin crossover complexes is an intensively studied topic. Starting from dinuclear iron(III)-salten complexes [Fe(salten)(pyS)]2(BPh4)2 and [Fe(thiotolylsalten)(NCS)]2 with disulfide-containing bridging ligands, corresponding mononuclear complexes [Fe(salten)(pyS)](+) and [Fe(thiotolylsalten)(NCS)] are covalently attached to Au(111) surfaces (pySH, pyridinethiol; salten, bis(3-salicylidene-aminopropyl)amine). The adsorbed monolayers are investigated by infrared reflection absorption spectroscopy (IRRAS) in combination with X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure (NEXAFS). Comparison of the surface vibrational spectra with bulk data allows us to draw conclusions with respect to the geometry of the adsorbed complexes. An anomaly is observed in the spectra of the surface-adsorbed monolayer of [Fe(salten)(pyS)](+), which suggests that the salten ligand is partially decoordinated from the Fe(III) center and one of its phenolate arms binds to the Au(111) surface. For complex [Fe(thiotolylsalten)(NCS)] that is bound to the Au(111) surface via a thiolate-functionalized salten ligand, this anomaly is not observed, which indicates that the coordination sphere of the complex in the bulk is retained on the surface. The implications of these results with respect to the preparation of surface-adsorbed monolayers of functional transition-metal complexes are discussed.

  10. Spectroscopic characterization of genetically modified flax fibers

    Science.gov (United States)

    Dymińska, L.; Gągor, A.; Hanuza, J.; Kulma, A.; Preisner, M.; Żuk, M.; Szatkowski, M.; Szopa, J.

    2014-09-01

    The principal goal of this paper is an analysis of flax fiber composition. Natural and genetically modified flax fibers derived from transgenic flax have been analyzed. Development of genetic engineering enables to improve the quality of fibers. Three transgenic plant lines with different modifications were generated based on fibrous flax plants as the origin. These are plants with: silenced cinnamyl alcohol dehydrogenase (CAD) gene; overexpression of polygalacturonase (PGI); and expression of three genes construct containing β-ketothiolase (phb A), acetoacetyl-CoA reductase (phb B), and poly-3-hydroxybutyric acid synthase (phb C). Flax fibers have been studied by FT-IR spectroscopy. The integral intensities of the IR bands have been used for estimation of the chemical content of the normal and transgenic flaxes. The spectroscopic data were compared to those obtained from chemical analysis of flax fibers. X-ray studies have been used to characterize the changes of the crystalline structure of the flax cellulose fibers.

  11. Plasma characterization on carbon fiber cathode by spectroscopic diagnostics

    Institute of Scientific and Technical Information of China (English)

    Liu Lie; Li Li-Min; Xu Qi-Fu; Chang Lei; Wen Jian-Chun

    2009-01-01

    This paper mainly investigates plasma characterization on carbon fiber cathodes with and without cesium iodide (CsI) coating powered by a~300 ns,~200 kV accelerating pulse. It was found that the CsI layers can not only improve the diode voltage,but also maintain a stable perveance.This indicates a slowly changed diode gap or a low cathode plasma expansion velocity.By spectroscopic diagnostics,in the vicinity of the cathode surface the average plasma density and temperature were found to be~3×1014 cm-3 and~5 eV,respectively,for an electron current density of~40 A/cm2.Furthermore,there exists a multicomponent plasma expansion toward the anode.The plasma expansion velocity,corresponding to the carbon and hydrogen ions,is estimated to be~1.5 cm/μs.Most notably,Cs spectroscopic line was obtained only at the distance ≤0.5 mm from the cathode surface.Carbon and hydrogen ions are obtained up to the distance of 2.5 mm from the cathode surface.Cs ions almost remain at the vicinity of the cathode surface.These results show that the addition of Cal enables a slow cathode plasma expansion toward the anode,providing a positive prospect for developing long-pulse electron beam sources.

  12. The Vegetation Red Edge Spectroscopic Feature as a Surface Biomarker

    CERN Document Server

    Seager, S

    2002-01-01

    The search for Earth-like extrasolar planets is in part motivated by the potential detection of spectroscopic biomarkers. Spectroscopic biomarkers are spectral features that are either consistent with life, indicative of habitability, or provide clues to a planet's habitability. Most attention so far has been given to atmospheric biomarkers, gases such as O2, O3, H2O, CO, and CH4. Here we discuss surface biomarkers. Surface biomarkers that have large, distinct, abrupt changes in their spectra may be detectable in an extrasolar planet's spectrum at wavelengths that penetrate to the planetary surface. Earth has such a surface biomarker: the vegetation "red edge" spectroscopic feature. Recent interest in Earth's surface biomarker has motivated Earthshine observations of the spatially unresolved Earth and two recent studies may have detected the vegetation red edge feature in Earth's hemispherically integrated spectrum. A photometric time series in different colors should help in detecting unusual surface feature...

  13. Photocatalytic reaction kinetics model based on electrical double layer theory Ⅱ. Infrared spectroscopic characterization of methyl orange adsorption on TiO2 surface

    Institute of Scientific and Technical Information of China (English)

    李新军; 李芳柏; 古国榜; 王良焱; 郑少健; 张琦

    2002-01-01

    In the process of heterogeneous photo-catalytic degradation, the reaction rate depends strongly on the property of organic binding on the surface. It is important to identify the adsorption of organic compounds on TiO2 surface to understand the mechanism of degradation and proper kinetics expression. The infrared spectroscopy was used to analyze the methyl orange adsorption on TiO2 surface in aqueous solutions in different pH ranges. The variation of the surface complexation of methyl orange formed on the TiO2 surface in different acid and basic media was discussed. And the adsorption amounts were also qualitatively analyzed. Methyl orange has strong, weak and little adsorption on the TiO2 surface in acid, basic and near neutral solution, respectively.

  14. Spectroscopic characterization of Antarctic marine aerosol

    Science.gov (United States)

    Paglione, Marco; Zanca, Nicola; Rinaldi, Matteo; Dall'osto, Manuel; Simo, Rafel; Facchini, Maria Cristina; Decesari, Stefano

    2017-04-01

    Marine aerosol constitutes an important and not thoroughly investigated natural aerosol system. In particular, the poor knowledge of the physical-chemical properties of primary (sea-spray) and secondary particles, especially over biologically active seawaters, affects the current capability of modeling the effect of marine aerosol on climate (O'Dowd et al., 2004). In polar regions, surface seawater composition and its exchanges with the atmosphere is complicated also by the presence of sea-ice and of the variety of micro-organisms (viruses, prokaryotes and microalgae) living within it (Levasseur,2013). In the framework of the Spanish project PEGASO (Plankton-derived Emission of Gases and Aerosols in the Southern Ocean) submicron aerosol samples were collected during a 6 weeks long oceanographic cruise (2nd January 2015 - 11th February 2015) conducted in the regions of Antarctic Peninsula, South Orkney and South Georgia Islands, an area of the Southern Ocean characterized every summer by both large patches of productive waters (phytoplankton blooms) and sea-ice cover. The collected samples were analyzed by means of proton-Nuclear Magnetic Resonance (H-NMR) spectroscopy with aim of organic compounds characterization in terms of functional groups and specific molecular tracers identification (Decesari et al., 2011). H-NMR spectral features resulted quite variable among the different samples both in terms of relative abundance of main functional groups and in terms of presence of specific compounds. In all the samples were found biogenic markers, like low-molecular-weight alkyl-amines and methanesulphonate (MSA), of secondary origin (formed by the condensation of vapors onto particles). Resonance signals of other aliphatic compounds of possible primary origin, like lipids, aminoacids (e.g. alanine) and sugars (e.g. sucrose) are present in variable concentrations in the samples. A hierarchical cluster analysis applied on the NMR spectra allowed to identify similarities

  15. Spectroscopic characterization of a single dangling bond on a bare Si(100)- c ( 4 × 2 ) surface for n - and p -type doping

    KAUST Repository

    Mantega, M.

    2012-07-19

    We investigate the charging state of an isolated single dangling bond formed on an unpassivated Si(100) surface with c(4×2) reconstruction, by comparing scanning tunneling microscopy and spectroscopy analysis with density functional theory calculations. The dangling bond is created by placing a single hydrogen atom on the bare surface with the tip of a scanning tunneling microscope. The H atom passivates one of the dimer dangling bonds responsible for the surface one-dimensional electronic structure. This leaves a second dangling at the reacted surface dimer which breaks the surface periodicity. We consider two possible H adsorption configurations for both the neutral and the doped situation (n- and p-type). In the case of n-doping we find that the single dangling bond state is doubly occupied and the most stable configuration is that with H bonded to the bottom Si atom of the surface dimer. In the case of p-doping the dangling bond is instead empty and the configuration with the H attached to the top atom of the dimer is the most stable. Importantly the two configurations have different scattering properties and phase shift fingerprints. This might open up interesting perspectives for fabricating a switching device by tuning the doping level or by locally charging the single dangling bond state. © 2012 American Physical Society.

  16. Surface enhanced Raman scattering spectroscopic waveguide

    Science.gov (United States)

    Lascola, Robert J; McWhorter, Christopher S; Murph, Simona H

    2015-04-14

    A waveguide for use with surface-enhanced Raman spectroscopy is provided that includes a base structure with an inner surface that defines a cavity and that has an axis. Multiple molecules of an analyte are capable of being located within the cavity at the same time. A base layer is located on the inner surface of the base structure. The base layer extends in an axial direction along an axial length of an excitation section. Nanoparticles are carried by the base layer and may be uniformly distributed along the entire axial length of the excitation section. A flow cell for introducing analyte and excitation light into the waveguide and a method of applying nanoparticles may also be provided.

  17. Surface enhanced Raman scattering spectroscopic waveguide

    Energy Technology Data Exchange (ETDEWEB)

    Lascola, Robert J; McWhorter, Christopher S; Murph, Simona H

    2015-04-14

    A waveguide for use with surface-enhanced Raman spectroscopy is provided that includes a base structure with an inner surface that defines a cavity and that has an axis. Multiple molecules of an analyte are capable of being located within the cavity at the same time. A base layer is located on the inner surface of the base structure. The base layer extends in an axial direction along an axial length of an excitation section. Nanoparticles are carried by the base layer and may be uniformly distributed along the entire axial length of the excitation section. A flow cell for introducing analyte and excitation light into the waveguide and a method of applying nanoparticles may also be provided.

  18. Spectroscopic characterizations of organic/inorganic nanocomposites

    Science.gov (United States)

    Govani, Jayesh R.

    2009-12-01

    In the present study, pure and 0.3 wt%, 0.4 wt%, as well as 0.5 wt% L-arginine doped potassium dihydrogen phosphate (KDP) crystals were grown using solution growth techniques and further subjected to infrared (IR) absorption and Raman studies for confirmation of chemical group functionalization for investigating the incorporation mechanism of the L-arginine organic material into the KDP crystal structure. Infrared spectroscopic analysis suggests that structural changes are occurring for the L-arginine molecule as a result of its interaction with the KPD crystal. Infrared spectroscopic technique confirms the disturbance of the N-H, C-H and C-N bonds of the amino acid, suggesting successful incorporation of L-arginine into the KDP crystals. Raman analysis also reveals modification of the N-H, C-H and C-N bonds of the amino acid, implying successful inclusion of L-arginine into the KDP crystals. With the help of Gaussian software, a prediction of possible incorporation mechanisms of the organic material was obtained from comparison of the simulated infrared and Raman vibrational spectra with the experimental results. Furthermore, we also studied the effect of L-arginine doping on the thermal stability of the grown KDP crystal by employing Thermo gravimetric analysis (TGA). TGA suggests that increasing the level of L-arginine doping speeds the decomposition process and it weakens the KDP crystal, which indicates successful doping of the KDP crystals with L-arginine amino acid. Urinary stones are one of the oldest and most widely spread diseases in humans, animals and birds. Many remedies have been employed through the ages for the treatment of urinary stones. Recent medicinal measures reflect the modern advances, which are based on surgical removal, percutaneous techniques and extracorporeal shock wave lithotripsy (ESWL). Although these procedures are valuable, they are quite expensive for most people. Furthermore, recurrence of these diseases is awfully frequent with

  19. Spectroscopic modeling and characterization of a collisionally confined laser-ablated plasma plume.

    Science.gov (United States)

    Sherrill, M E; Mancini, R C; Bailey, J; Filuk, A; Clark, B; Lake, P; Abdallah, J

    2007-11-01

    Plasma plumes produced by laser ablation are an established method for manufacturing the high quality stoichiometrically complex thin films used for a variety of optical, photoelectric, and superconducting applications. The state and reproducibility of the plasma close to the surface of the irradiated target plays a critical role in producing high quality thin films. Unfortunately, this dense plasma has historically eluded quantifiable characterization. The difficulty in modeling the plume formation arises in the accounting for the small amount of energy deposited into the target when physical properties of these exotic target materials are not known. In this work we obtain the high density state of the plasma plume through the use of an experimental spectroscopic technique and a custom spectroscopic model. In addition to obtaining detailed temperature and density profiles, issues regarding line broadening and opacity for spectroscopic characterization will be addressed for this unique environment.

  20. Expression, purification and spectroscopic characterization of the Regulator complex

    Energy Technology Data Exchange (ETDEWEB)

    Nogueira, M.L.C.; Silva, A.L.S.; Camilotti, D.; Silva, C.A.; Sforca, M.L.; Smetana, J.H.C.; Zeri, A.C. [Laboratorio Nacional de Biociencias - LNBIO, Campinas, SP (Brazil); Ospina-Bedoya, M. [Universidad de Antioquia, Medellin (Colombia)

    2012-07-01

    Full text: The mammalian target of rapamycin (mTOR) signaling pathway integrates both intracellular and extracellular signals, serves as a central regulator of cell metabolism in humans and its deregulation is linked to diseases like cancer and diabetes. The small GTPases Rag are mediators of signaling by amino acid (leucine). These GT-Pases are anchored on the surface of the lysosome through an interaction with a complex of three proteins, p18, MP1 and p14, called Ragulator. The p18 protein is responsible for interaction with the lysosomal membrane through its N terminal post translational modification. The objective of this project is to study the interaction of p18 and other components of the Ragulator complex. The p18 protein was expressed in inclusion bodies, which were isolated and solubilized in urea. p18 was renatured with its partners MP1/p14 and this complex, the Ragulator, was subjected to spectroscopic characterization using circular dichroism and dynamic light scattering. (author)

  1. Scattered surface charge density: A tool for surface characterization

    KAUST Repository

    Naydenov, Borislav

    2011-11-28

    We demonstrate the use of nonlocal scanning tunneling spectroscopic measurements to characterize the local structure of adspecies in their states where they are significantly less perturbed by the probe, which is accomplished by mapping the amplitude and phase of the scattered surface charge density. As an example, we study single-H-atom adsorption on the n-type Si(100)-(4 × 2) surface, and demonstrate the existence of two different configurations that are distinguishable using the nonlocal approach and successfully corroborated by density functional theory. © 2011 American Physical Society.

  2. Detectors and cooling technology for direct spectroscopic biosignature characterization

    CERN Document Server

    Rauscher, Bernard J; Moseley, S H; Sadleir, John E; Stevenson, Thomas

    2016-01-01

    Direct spectroscopic biosignature characterization (hereafter "biosignature characterization") will be a major focus for future space observatories equipped with coronagraphs or starshades. Our aim in this article is to provide an introduction to potential detector and cooling technologies for biosignature characterization. We begin by reviewing the needs. These include nearly noiseless photon detection at flux levels as low as $<0.001~\\textrm{photons}~s^{-1}~\\textrm{pixel}^{-1}$ in the visible and near-IR. We then discuss potential areas for further testing and/or development to meet these needs using non-cryogenic detectors (EMCCD, HgCdTe array, HgCdTe APD array), and cryogenic single photon detectors (MKID arrays and TES microcalorimeter arrays). Non-cryogenic detectors are compatible with the passive cooling that is strongly preferred by coronagraphic missions, but would add non-negligible noise. Cryogenic detectors would require active cooling, but in return deliver nearly quantum limited performance....

  3. Spectroscopic Methods of Remote Sensing for Vegetation Characterization

    Science.gov (United States)

    Kokaly, R. F.

    2013-12-01

    Imaging spectroscopy (IS), often referred to as hyperspectral remote sensing, is one of the latest innovations in a very long history of spectroscopy. Spectroscopic methods have been used for understanding the composition of the world around us, as well as, the solar system and distant parts of the universe. Continuous sampling of the electromagnetic spectrum in narrow bands is what separates IS from previous forms of remote sensing. Terrestrial imaging spectrometers often have hundreds of channels that cover the wavelength range of reflected solar radiation, including the visible, near-infrared (NIR), and shortwave infrared (SWIR) regions. In part due to the large number of channels, a wide variety of methods have been applied to extract information from IS data sets. These can be grouped into several broad classes, including: multi-channel indices, statistical procedures, full spectrum mixing models, and spectroscopic methods. Spectroscopic methods carry on the more than 150 year history of laboratory-based spectroscopy applied to material identification and characterization. Spectroscopic methods of IS relate the positions and shapes of spectral features resolved by airborne and spaceborne sensors to the biochemical and physical composition of vegetation in a pixel. The chlorophyll 680nm, water 980nm, water 1200nm, SWIR 1700nm, SWIR 2100nm, and SWIR 2300nm features have been the subject of study. Spectral feature analysis (SFA) involves isolating such an absorption feature using continuum removal (CR) and calculating descriptors of the feature, such as center position, depth, width, area, and asymmetry. SFA has been applied to quantify pigment and non-pigment biochemical concentrations in leaves, plants, and canopies. Spectral feature comparison (SFC) utilizes CR of features in each pixel's spectrum and linear regression with continuum-removed features in reference spectra in a library of known vegetation types to map vegetation species and communities. SFC has

  4. Spectroscopic study of cystine adsorption on pyrite surface: From vacuum to solution conditions

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Arenillas, M.; Mateo-Marti, E., E-mail: mateome@cab.inta-csic.es

    2015-09-08

    Highlights: • Successful adsorption of cystine on pyrite surface under several conditions. • Detailed XPS spectroscopic characterization of cystine adsorption on pyrite surface. • Spectroscopy evidence, oxidation and anoxic conditions adjust molecular adsorption. • Molecular chemistry on pyrite is driven depending on the surrounding conditions. • The cystine/pyrite(100) model is in good agreement with Wächtershäuser’s theory. - Abstract: We characterized the adsorption of cystine molecules on pyrite surface via X-ray photoelectron spectroscopy. Anoxic conditions were simulated under ultra-high-vacuum conditions. In contrast, to simulate oxidation conditions, the molecules were adsorbed on pyrite surface from solution. A novel comparative analysis revealed remarkable differences with respect to molecular adsorption and surface chemistry induced by environmental conditions. Molecular adsorption under anoxic conditions was observed to be more favorable, concentrating a large number of molecules on the surface and two different chemical species. In contrast, the presence of oxygen induced an autocatalytic oxidation process on the pyrite surface, which facilitated water binding on pyrite surface and partially blocked molecular adsorption. Pyrite is a highly reactive surface and contains two crucial types of surface functional groups that drive molecular chemistry on the surface depending on the surrounding conditions. Therefore, the system explored in this study holds interesting implications for supporting catalyzed prebiotic chemistry reactions.

  5. Characterization by spectroscopic Ellipsometry, the physical properties of silver nanoparticles.

    Science.gov (United States)

    Coanga, Jean-Maurice

    2013-04-01

    Physicists are able to change their minds through their experiments. I think it is time to go kick the curse and go further in research if we want a human future. I work in the Nano-Optics and Plasmonics research. I defined with ellipsomètrie the structure of new type of Nano particles of silver. It's same be act quickly to replace the old dirty leaded electronic-connexion chip and by the other hand to find a new way for the heath care of cancer disease by nanoparticles the next killers of bad cells. Silver nanoparticle layers are obtained by Spark Plasma Sintering are investigated as an alternative to lead alloy based material for solder joint in power mechatronics modules. These layers are characterized by mean of conventional techniques that is the dilatometry technique, the resistivity measurement through the van der Pauw method, and the flash laser technique. Furthermore, the nanoparticles of silver layer are deeply studied by UV-Visible spectroscopic ellipsometry. Spectroscopic angles parameters are determined in function of temperature and dielectric constants are deduced and analyzed through an optical model which takes into account a Drude and a Lorentz component within the Bruggeman effective medium approximation (EMA). The relaxation times and the electrical conductivity are plot in function of temperature. The obtained electrical conductivity give significant result in good agreement to those reported by four points electrical measurement method.

  6. Spectroscopic studies of anthracyclines: Structural characterization and in vitro tracking

    Science.gov (United States)

    Szafraniec, Ewelina; Majzner, Katarzyna; Farhane, Zeineb; Byrne, Hugh J.; Lukawska, Malgorzata; Oszczapowicz, Irena; Chlopicki, Stefan; Baranska, Malgorzata

    2016-12-01

    A broad spectroscopic characterization, using ultraviolet-visible (UV-vis) and Fourier transform infrared absorption as well as Raman scattering, of two commonly used anthracyclines antibiotics (DOX) daunorubicin (DNR), their epimers (EDOX, EDNR) and ten selected analogs is presented. The paper serves as a comprehensive spectral library of UV-vis, IR and Raman spectra of anthracyclines in the solid state and in solution. The particular advantage of Raman spectroscopy for the measurement and analysis of individual antibiotics is demonstrated. Raman spectroscopy can be used to monitor the in vitro uptake and distribution of the drug in cells, using both 488 nm and 785 nm as source wavelengths, with submicrometer spatial resolution, although the cellular accumulation of the drug is different in each case. The high information content of Raman spectra allows studies of the drug-cell interactions, and so the method seems very suitable for monitoring drug uptake and mechanisms of interaction with cellular compartments at the subcellular level.

  7. Amino Acid and Peptide Immobilization on Oxidized Nanocellulose: Spectroscopic Characterization

    Directory of Open Access Journals (Sweden)

    Claude Daneault

    2012-06-01

    Full Text Available In this work, oxidized nanocellulose (ONC was synthesized and chemically coupled with amino acids and peptides using a two step coupling method at room temperature. First, ONC was activated by N-ethyl-N’-(3-dimethylaminopropyl carbodiimide hydrochloride, forming a stable active ester in the presence of N-hydroxysuccinimide. Second, the active ester was reacted with the amino group of the amino acid or peptide, forming an amide bond between ONC and the grafted molecule. Using this method, the intermolecular interaction of amino acids and peptides was avoided and uniform coupling of these molecules on ONC was achieved. The coupling reaction was very fast in mild conditions and without alteration of the polysaccharide. The coupling products (ONC-amino acids and ONC-peptides were characterized by transmission electron microscopy and by the absorption, emission, Fourier transform infrared spectroscopy (FTIR and X-ray photoelectron spectroscopy (XPS spectroscopic techniques.

  8. Spectroscopic characterization of dissolved organic matter isolated from rainwater.

    Science.gov (United States)

    Santos, Patrícia S M; Otero, Marta; Duarte, Regina M B O; Duarte, Armando C

    2009-02-01

    Rainwater is a matrix containing extremely low concentrations (in the range of muM C) of dissolved organic carbon (DOC) and for its characterization, an efficient extraction procedure is essential. A recently developed procedure based on adsorption onto XAD-8 and XAD-4 resins in series was used in this work for the extraction and isolation of rainwater dissolved organic matter (DOM). Prior to the isolation and fractionation of DOM, and to obtain sufficient mass for the spectroscopic analyses, individual rainwater samples were batched together according to similar meteorological conditions on a total of three composed samples. The results of the isolation procedure indicated that the resin tandem procedure is not applicable for rainwater DOM since the XAD-4 resin caused samples contamination. On the other hand, the XAD-8 resin allowed DOM recoveries of 39.9-50.5% of the DOC of the original combined samples. This recovered organic fraction was characterized by UV-visible, molecular fluorescence, FTIR-ATR and 1H NMR spectroscopies. The chemical characterization of the rainwater DOM showed that the three samples consist mostly of hydroxylated and carboxylic acids with a predominantly aliphatic character, containing a minor component of aromatic structures. The obtained results suggest that the DOM in rainwater, and consequently in the precursor atmospheric particles, may have a secondary origin via the oxidation of volatile organic compounds from different origins.

  9. Spectroscopic characterization of schiff base-copper complexes immobilized in smectite clays

    Directory of Open Access Journals (Sweden)

    Patrícia M. Dias

    2010-01-01

    Full Text Available Herein, the immobilization of some Schiff base-copper(II complexes in smectite clays is described as a strategy for the heterogenization of homogeneous catalysts. The obtained materials were characterized by spectroscopic techniques, mostly UV/Vis, EPR, XANES and luminescence spectroscopy. SWy-2 and synthetic Laponite clays were used for the immobilization of two different complexes that have previously shown catalytic activity in the dismutation of superoxide radicals, and disproportionation of hydrogen peroxide. The obtained results indicated the occurrence of an intriguing intramolecular redox process involving copper and the imine ligand at the surface of the clays. These studies are supported by computational calculations.

  10. Spectroscopic ellipsometric and Raman spectroscopic investigations of pulsed laser treated glassy carbon surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Csontos, J., E-mail: jcsontos@titan.physx.u-szeged.hu [University of Szeged, Department of Optics and Quantum Electronics, Dóm tér 9, H-6720 Szeged (Hungary); Pápa, Z.; Gárdián, A. [University of Szeged, Department of Optics and Quantum Electronics, Dóm tér 9, H-6720 Szeged (Hungary); Füle, M. [University of Szeged, Department of Experimental Physics, Dóm tér 9, H-6720 Szeged (Hungary); Budai, J. [University of Szeged, Department of Optics and Quantum Electronics, Dóm tér 9, H-6720 Szeged (Hungary); Toth, Z. [University of Szeged, Department of Optics and Quantum Electronics, Dóm tér 9, H-6720 Szeged (Hungary); University of Szeged, Department of Oral Biology and Experimental Dental Research, Tisza Lajos krt. 64, H-6720 Szeged (Hungary)

    2015-05-01

    Highlights: • Laser treatment modifies the top layer of glassy carbon as shown by ellipsometry. • Raman signal is composed from signals of the layer and the glassy carbon substrate. • Using volumetric fluence allows to compare the effects of different lasers. • Melting effects of glassy carbon was observed in case of Nd:YAG laser treatment. - Abstract: In this study spectroscopic ellipsometry (SE) and Raman spectroscopy are applied to study structural modification of glassy carbon, due to high intensity laser ablation. Two KrF lasers with different pulse durations (480 fs and 18 ns), an ArF (20 ns), and a frequency doubled Nd:YAG laser (8 ns) were applied to irradiate the surface of glassy carbon targets. The main characteristics of the different laser treatments are compared by introducing the volumetric fluence which takes into account the different absorption values at different wavelengths. SE showed the appearance of a modified layer on the ablated surfaces. In the case of the ns lasers the thickness of this layer was in the range of 10–60 nm, while in the case of fs laser it was less than 20 nm. In all cases the average refractive index (n) of the modified layers slightly decreased compared to the refractive index of glassy carbon. Increase in extinction coefficient (k) was observed in the cases of ArF and fs KrF laser treatment, while the k values decreased significantly in the cases of nanosecond pulse duration KrF and Nd:YAG laser treatments. In the Raman spectra of the ablated areas the characteristic D and G peaks were widened due to appearance of an amorphous phase. Both Raman spectroscopy and SE indicate that the irradiated areas show carbon nanoparticle formation in all cases.

  11. Synthesis, Characterization, and Surface Initiated Polymerization of Carbazole Functionalized Isocyanides

    NARCIS (Netherlands)

    Schwartz, Erik; Lim, Eunhee; Gowda, Chandrakala M.; Liscio, Andrea; Fenwick, Oliver; Tu, Guoli; Palermo, Vincenzo; Gelder, de Rene; Cornelissen, Jeroen J.L.M.; Eck, van Ernst R.H.; Kentgens, Arno P.M.; Cacialli, Franco; Nolte, Roeland J.M.; Samori, Paolo; Huck, Wilhelm T.S.; Rowan, Alan E.

    2010-01-01

    We describe the design and synthesis of carbazole functionalized isocyanides and the detailed investigation of their properties. Characterization by solid state NMR, CD, and IR spectroscopic techniques reveals that the polymer has a well-defined helical architecture. Surface-initiated polymerization

  12. Nanoshell-based substrates for surface enhanced spectroscopic detection of biomolecules.

    Science.gov (United States)

    Levin, Carly S; Kundu, Janardan; Barhoumi, Aoune; Halas, Naomi J

    2009-09-01

    Nanoshells are optically tunable core-shell nanostructures with demonstrated uses in surface enhanced spectroscopies. Based on their ability to support surface plasmons, which give rise to strongly enhanced electromagnetic fields at their surface, nanoshells provide simple, scalable, high-quality substrates. In this article, we outline the development and use of nanoshell-based substrates for direct, spectroscopic detection of biomolecules. Recent advances in the use of these nanostructures lead to improved spectroscopic quality, selectivity, and reproducibility.

  13. Optical Characterization of Nanostructured Surfaces

    DEFF Research Database (Denmark)

    Feidenhans'l, Nikolaj Agentoft

    spectrum; the new method only evaluates the color of the reflected light using a standard RGB color camera. Color scatterometry provides the combined advantages of spectroscopic scatterometry, which provides fast evaluations, and imaging scatterometry that provides an overview image from which small...... implementation, a range of complementing characterization methods is needed to perform high-speed quality control of the nanostructures. This thesis concerns the development of a new method for fast in-line characterization of periodic nanostructures. The focus is on optical scatterometry, which uses inverse......, with trapezoidal profiles approximately ~200 nm high and with periods between 600 nm and 5000 nm. The heights and filling factors are determined with an accuracy of ~8 %, while the sidewall slopes have larger uncertainties due to a lower influence on the reflected light. The thesis also evaluates the use...

  14. Spectroscopic characterization of III-V semiconductor nanomaterials

    Science.gov (United States)

    Crankshaw, Shanna Marie

    through a novel spectroscopic technique first formulated for the rather different purpose of dispersion engineering for slow-light schemes. The frequency-resolved technique combined with the unusual (110) quantum wells in a furthermore atypical waveguide experimental geometry has revealed fascinating behavior of electron spin splitting which points to the possibility of optically orienting electron spins with linearly polarized light---an experimental result supporting a theoretical description of the phenomenon itself only a few years old. Lastly, to explore a space of further-restricted dimensionality, the final chapters describe InP semiconductor nanowires with dimensions small enough to be considered truly one-dimensional. Like the bulk GaAs of the first few chapters, the InP nanowires here crystallize in a wurtzite structure. In the InP nanowire case, though, the experimental techniques explored for characterization are temperature-dependent time-integrated photoluminescence at the single-wire level (including samples with InAsP insertions) and time-resolved photoluminescence at the ensemble level. The carrier dynamics revealed through these time-resolved studies are the first of their kind for wurtzite InP nanowires. The chapters are thus ordered as a progression from three (bulk), to two (quantum well), to one (nanowire), to zero dimensions (axially-structured nanowire), with the uniting theme the emphasis on connecting the semiconductor nanomaterials' crystallinity to its exhibited properties by relevant experimental spectroscopic techniques, whether these are standard methods or effectively invented for the case at hand.

  15. SPECTROSCOPIC PROBING OF POTENTIAL SURFACES IN REACTIVE COLLISIONS

    OpenAIRE

    Telle, H.

    1985-01-01

    For the investigation of unstable intermediates, ABC*, which constitute the "transition states" in some simple reactive collisions, spectroscopic methods are beginning to provide valuable results. In a (relatively) simple approach molecules are photodissociated, and the interaction potentials during the process of separation (half-collision) are mapped in either absorption or emission ; the method will be described exemplary for the photolysis of NaI, giving rise to emission from NaI≠*. For r...

  16. Identification and spectroscopic characterization of nonheme iron(III) hypochlorite intermediates

    OpenAIRE

    Draksharapu, Apparao; Angelone, Davide; Quesne, Matthew G.; Padamati, Sandeep K; Gómez Martín, Laura; Hage, Ronald; Costas Salgueiro, Miquel; Browne, Wesley R.; de Visser, Sam P.

    2015-01-01

    FeIII-hypohalite complexes have been implicated in a wide range of important enzyme-catalyzed halogenation reactions including the biosynthesis of natural products and antibiotics and post-translational modification of proteins. The absence of spectroscopic data on such species precludes their identification. Herein, we report the generation and spectroscopic characterization of nonheme FeIII-hypohalite intermediates of possible relevance to iron halogenases. We show that FeIII-OCl polypyridy...

  17. Spectroscopic ellipsometry characterization of thin-film silicon nitride

    Energy Technology Data Exchange (ETDEWEB)

    Jellison, G.E. Jr.; Modine, F.A. [Oak Ridge National Lab., TN (United States); Doshi, P.; Rohatgi, A. [Georiga Inst. of Technology, Atlanta, GA (United States)

    1997-05-01

    We have measured and analyzed the optical characteristics of a series of silicon nitride thin films prepared by plasma-enhanced chemical vapor deposition on silicon substrates for photovoltaic applications. Spectroscopic ellipsometry measurements were made by using a two-channel spectroscopic polarization modulator ellipsometer that measures N, S, and C data simultaneously. The data were fit to a model consisting of air / roughness / SiN / crystalline silicon. The roughness was modeled using the Bruggeman effective medium approximation, assuming 50% SiN, 50% voids. The optical functions of the SiN film were parameterized using a model by Jellison and Modine. All the {Chi}{sup 2} are near 1, demonstrating that this model works extremely well for all SiN films. The measured dielectric functions were used to make optimized SiN antireflection coatings for crystalline silicon solar cells.

  18. Spectroscopic characterization of a Nigerian standard sand: Igbokoda sand

    CSIR Research Space (South Africa)

    Ojuri, OO

    2017-01-01

    Full Text Available the Middle Ordovician St. Peter Sandstone near Ottawa, Illinois, had been picked by the American Society for Testing and Materials (ASTM) as the reference sand to employ in testing cement and strength of concrete [9]. To the best of our knowledge... and magnetic resonance spectroscopic techniques due to its importance in cement, geotechnical/geo-environmental research in Nigeria. This should halt importation of standard silica sand for mortar and concrete testing...

  19. Surface characterization of silicate bioceramics.

    Science.gov (United States)

    Cerruti, Marta

    2012-03-28

    The success of an implanted prosthetic material is determined by the early events occurring at the interface between the material and the body. These events depend on many surface properties, with the main ones including the surface's composition, porosity, roughness, topography, charge, functional groups and exposed area. This review will portray how our understanding of the surface reactivity of silicate bioceramics has emerged and evolved in the past four decades, owing to the adoption of many complementary surface characterization tools. The review is organized in sections dedicated to a specific surface property, each describing how the property influences the body's response to the material, and the tools that have been adopted to analyse it. The final section introduces the techniques that have yet to be applied extensively to silicate bioceramics, and the information that they could provide.

  20. Spectroscopic characterization of sixteenth century panel painting references using Raman, surface-enhanced Raman spectroscopy and helium-Raman system for in situ analysis of Ibero-American Colonial paintings

    Science.gov (United States)

    García-Bucio, María Angélica; Casanova-González, Edgar; Ruvalcaba-Sil, José Luis; Arroyo-Lemus, Elsa; Mitrani-Viggiano, Alejandro

    2016-12-01

    Colonial panel paintings constitute an essential part of Latin-American cultural heritage. Their study is vital for understanding the manufacturing process, including its evolution in history, as well as its authorship, dating and other information significant to art history and conservation purposes. Raman spectroscopy supplies a non-destructive characterization tool, which can be implemented for in situ analysis, via portable equipment. Specific methodologies must be developed, comprising the elaboration of reference panel paintings using techniques and materials similar to those of the analysed period, as well as the determination of the best analysis conditions for different pigments and ground preparations. In order to do so, Raman spectroscopy at 532, 785 and 1064 nm, surface-enhanced Raman spectroscopy (SERS) and a helium-Raman system were applied to a panel painting reference, in combination with X-ray fluorescence analysis. We were able to establish the analysis conditions for a number of sixteenth century pigments and dyes, and other relevant components of panel paintings from this period, 1064 nm Raman and SERS being the most successful. The acquired spectra contain valuable specific information for their identification and they conform a very useful database that can be applied to the analysis of Ibero-American Colonial paintings. This article is part of the themed issue "Raman spectroscopy in art and archaeology".

  1. 1-(4-(6-Fluorobenzo [d] isoxazol-3-yl) piperidin-1-yl)-2-(4-(hydroxymethyl)-1H-1,2,3-triazol-1-yl) ethanone: Synthesis, spectroscopic characterization, Hirshfeld surface analysis, cytotoxic studies and docking studies

    Science.gov (United States)

    Govindhan, M.; Viswanathan, V.; Karthikeyan, S.; Subramanian, K.; Velmurugan, D.

    2017-08-01

    Compound 1-(4-(6-fluorobenzo[d] isoxazol-3-yl) piperidin-1-yl)-2-(4-(hydroxymethyl)-1H-1, 2,3-triazol-1-yl) ethanone was synthesized in good yield by using click chemistry approach with 2-azido-1-(4-(6-flurobenzo[d]isooxazol-3-yl)piperidin-1-yl)ethanone as a starting material. The synthesized compound was characterized using IR, NMR and MS studies. Thermal stability of the compound was analyzed by using TGA and DSC technique. The single crystal XRD analysis was taken part, to confirm the structure of the compound. The intercontacts in the crystal structure are analyzed using Hirshfeld surfaces computational method. Cytotoxicity of the synthesized compound was evaluated and the results were reported. The binding analysis carried out between the newly synthesized molecule with human serum albumin using fluorescence spectroscopy technique to understand the pharmacokinetics nature of the compound for further biological application. The molecular docking studies were evaluated for the compound to elucidate insights of new molecules in carrier protein.

  2. Spectroscopic characterization and detection of Ethyl Mercaptan in Orion

    OpenAIRE

    Kolesniková, L.,; Tercero, B.; Cernicharo, J.; Alonso, J. L.; Daly, A. M.; Gordon, B. P.; Shipman, S. T.

    2014-01-01

    New laboratory data of ethyl mercaptan, CH$_{3}$CH$_{2}$SH, in the millimeter and submillimeter-wave domains (up to 880 GHz) provided very precise values of the spectroscopic constants that allowed the detection of $gauche$-CH$_3$CH$_2$SH towards Orion KL. 77 unblended or slightly blended lines plus no missing transitions in the range 80-280 GHz support this identification. A detection of methyl mercaptan, CH$_{3}$SH, in the spectral survey of Orion KL is reported as well. Our column density ...

  3. Spectroscopic characterization and detection of Ethyl Mercaptan in Orion

    CERN Document Server

    Kolesniková, L; Cernicharo, J; Alonso, J L; Daly, A M; Gordon, B P; Shipman, S T

    2014-01-01

    New laboratory data of ethyl mercaptan, CH$_{3}$CH$_{2}$SH, in the millimeter and submillimeter-wave domains (up to 880 GHz) provided very precise values of the spectroscopic constants that allowed the detection of $gauche$-CH$_3$CH$_2$SH towards Orion KL. 77 unblended or slightly blended lines plus no missing transitions in the range 80-280 GHz support this identification. A detection of methyl mercaptan, CH$_{3}$SH, in the spectral survey of Orion KL is reported as well. Our column density results indicate that methyl mercaptan is $\\simeq$ 5 times more abundant than ethyl mercaptan in the hot core of Orion KL.

  4. SPECTROSCOPIC, THERMAL, AND ANATOMICAL CHARACTERIZATION OF CULTIVATED BAMBOO (GIGANTOCHLOA SPP.

    Directory of Open Access Journals (Sweden)

    Irshad ul Haq Bhat

    2011-04-01

    Full Text Available This paper presents spectroscopic, thermal, and morphological properties of two bamboo species viz. Gigantochloa brang and Gigantochloa wrayi. The nature of cell wall structure and distribution of vascular bundles in G. brang and G. wrayi were studied by scanning electron microscopy and transmission electron microscopy techniques. Gigantochloa spp. at various positions and locations showed identical thermal stability and are stable up to 200 °C. The decomposition of cellulose and hemicelluloses component of the culm occurred between 220 °C and 390 °C, while the degradation of lignin takes place above 400 °C.

  5. Life Finder Detectors; Detector Needs and Status for Spectroscopic Biosignature Characterization

    Science.gov (United States)

    Rauscher, Bernard J.; Bolcar, Matthew R.; Clampin, Mark; Domagal-Goldman, Shawn; McElwain, Michael W.; Moseley, Samuel H.; Stahle, Carl; Stark, Christopher C.; Thronson, Harley A.

    2016-01-01

    The search for life on other worlds looms large in NASA's future. Outside our solar system, direct spectroscopic biosignature characterization using very large UV-Optical-IR telescopes with coronagraphs or starshades is a core technique to both AURA's High Definition Space Telescope (HDST) concept and NASA's 30-year strategic plan. These giant space observatories require technological advancements in several areas, one of which is detectors. In this presentation, we review the detector requirements for spectroscopic biosignature characterization and discuss the status of some existing and proposed detector technologies for meeting them.

  6. Spectroscopic characterization of the atmospheres of potentially habitable planets: GL 581 d as a model case study

    CERN Document Server

    von Paris, Philip; Godolt, Mareike; Grenfell, J Lee; Hedelt, Pascal; Rauer, Heike; Schreier, Franz; Stracke, Barbara

    2011-01-01

    (abridged) The Super-Earth candidate GL 581 d is the first potentially habitable extrasolar planet. Therefore, GL 581 d is used to illustrate a hypothetical detailed spectroscopic characterization of such planets. Atmospheric profiles from 1D radiative-convective model scenarios of GL 581 d were used to calculate high-resolution synthetic spectra. From the spectra, signal-to-noise ratios were calculated for a telescope such as the planned James Webb Space Telescope. The presence of the model atmospheres could be clearly inferred from the calculated synthetic spectra due to strong water and carbon dioxide absorption bands. Surface temperatures could be inferred for model scenarios with optically thin spectral windows. Dense, CO2-rich scenarios did not allow for the characterization of surface temperatures and to assess habitability. Degeneracies between CO2 concentration and surface pressure further complicated the interpretation of the calculated spectra, hence the determination of atmospheric conditions. Sti...

  7. SPECTROSCOPIC CHARACTERIZATION AND DETECTION OF ETHYL MERCAPTAN IN ORION

    Energy Technology Data Exchange (ETDEWEB)

    Kolesniková, L.; Alonso, J. L.; Daly, A. M. [Grupo de Espectroscopía Molecular (GEM), Edificio Quifima, Laboratorios de Espectroscopía y Bioespectroscopía, Parque Científico UVa, Unidad Asociada CSIC, Universidad de Valladolid, E-47011 Valladolid (Spain); Tercero, B.; Cernicharo, J. [Departamento de Astrofísica, Centro de Astrobiología CAB, CSIC-INTA, Ctra. de Torrejón a Ajalvir km 4, E-28850 Madrid (Spain); Gordon, B. P.; Shipman, S. T., E-mail: lucie.kolesnikova@uva.es, E-mail: jlalonso@qf.uva.es, E-mail: adammichael.daly@uva.es, E-mail: terceromb@cab.inta-csic.es, E-mail: jcernicharo@cab.inta-csic.es, E-mail: brittany.gordon@ncf.edu, E-mail: shipman@ncf.edu [Division of Natural Sciences, New College of Florida, Sarasota, FL 34243 (United States)

    2014-03-20

    New laboratory data of ethyl mercaptan, CH{sub 3}CH{sub 2}SH, in the millimeter- and submillimeter-wave domains (up to 880 GHz) provided very precise values of the spectroscopic constants that allowed the detection of gauche-CH{sub 3}CH{sub 2}SH toward Orion KL. This identification is supported by 77 unblended or slightly blended lines plus no missing transitions in the range 80-280 GHz. A detection of methyl mercaptan, CH{sub 3}SH, in the spectral survey of Orion KL is reported as well. Our column density results indicate that methyl mercaptan is ≅ 5 times more abundant than ethyl mercaptan in the hot core of Orion KL.

  8. Fourier–transform infrared spectroscopic characterization of naturally occurring glassy fulgurites

    Indian Academy of Sciences (India)

    B J Saikia; G Parthasarathy; N C Sarmah; G D Baruah

    2008-04-01

    We report here for the first time the spectroscopic characterization of natural fulgurites of Garuamukh. On April 22, 2005 at 04 : 00 local time, large amounts of black-brown colour of colloidal solution came out from below the earth’s surface at Garuamukh near Nagaon town (latitude 26°20′39″N, longitude 92°41′39″E, Assam, India) with fire and smoke. This colloidal solution got transformed into fulgurites, glassy material, within a few hours. We present here the characterization of the fulgurites by Fourier transform infrared (FTIR) absorption, X-ray diffraction and X-ray fluorescence methods. The amorphous nature of the substance has been confirmed by Fourier transform infrared spectra of the fulgurites, which exhibit prominent absorption band in the region 400–1200 cm-1, the basic component of amorphous silica. The present study might have significant implications in understanding the thermodynamic properties of naturally occurring glasses, which are formed by shock metamorphism.

  9. Spectroscopic determination of optimal hydration time of zircon surface

    Energy Technology Data Exchange (ETDEWEB)

    Ordonez R, E. [ININ, Departamento de Quimica, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico); Garcia R, G. [Instituto Tecnologico de Toluca, Division de Estudios del Posgrado, Av. Tecnologico s/n, Ex-Rancho La Virgen, 52140 Metepec, Estado de Mexico (Mexico); Garcia G, N., E-mail: eduardo.ordonez@inin.gob.m [Universidad Autonoma del Estado de Mexico, Facultad de Quimica, Av. Colon y Av. Tollocan, 50180 Toluca, Estado de Mexico (Mexico)

    2010-07-01

    When a mineral surface is immersed in an aqueous solution, it develops and electric charge produced by the amphoteric dissociation of hydroxyl groups created by the hydration of the solid surface. This is one influential surface property. The complete hydration process takes a time which is specific for each mineral species. The knowledge of the aqueous solution contact time for complete surface hydration is mandatory for further surface phenomena studies. This study deals with the optimal hydration time of the raw zircon (ZrSiO{sub 4}) surface comparing the classical potentiometric titrations with a fluorescence spectroscopy technique. The latter is easy and rea liable as it demands only one sample batch to determine the optimal time to ensure a total hydration of the zircon surface. The analytical results of neutron activation analysis showed the presence of trace quantities of Dy{sup 3+}, Eu{sup 3+} and Er{sup 3} in the bulk of zircon. The Dy{sup 3+} is structured in the zircon crystalline lattice and undergoes the same chemical reactions as zircon. Furthermore, the Dy{sup 3+} has a good fluorescent response whose intensity is enhanced by hydration molecules. The results show that, according to the potentiometric analysis, the hydration process for each batch (at least 8 sample batches) takes around 2 h, while the spectrometric method indicates only 5 minutes from only one batch. Both methods showed that the zircon surface have a 16 h optimal hydration time. (Author)

  10. Far-infrared Spectroscopic Characterization of Anti-vinyl Alcohol

    Science.gov (United States)

    Bunn, Hayley; Soliday, Rebekah M.; Sumner, Isaiah; Raston, Paul L.

    2017-09-01

    We report a detailed analysis of the high-resolution far-infrared spectrum of anti-vinyl alcohol, which has been previously identified toward Sagittarius B2(N). The ν 15 OH torsional fundamental investigated here is more than 200 cm‑1 removed from the next nearest vibration, making it practically unperturbed and ideal to help refine the ground state rotational constants that were previously determined from 25 microwave lines. We assigned 1335 lines within the ν 15 fundamental centered at 261.5512 cm‑1, with J and K a ranges of 1–59 and 0–16, respectively. The microwave and far-infrared line positions were fit with Watson-type A- and S-reduced Hamiltonians, with the inclusion of quartic and select sextic distortion terms. This resulted in a significant refinement of the ground state constants, in addition to the determination of the {ν }15=1 state constants for the first time. The spectroscopic parameters are in good agreement with the results from anharmonic coupled-cluster calculations, and should be useful in searches for rotationally and/or vibrationally warm anti-vinyl alcohol in interstellar molecular clouds.

  11. Impedance spectroscopic characterization of gadolinium substituted cobalt ferrite ceramics

    Science.gov (United States)

    Rahman, Md. T.; Ramana, C. V.

    2014-10-01

    Gadolinium (Gd) substituted cobalt ferrites (CoFe2-xGdxO4, referred to CFGO) with variable Gd content (x = 0.0-0.4) have been synthesized by solid state ceramic method. The crystal structure and impedance properties of CFGO compounds have been evaluated. X-ray diffraction measurements indicate that CFGO crystallize in the inverse spinel phase. The CFGO compounds exhibit lattice expansion due to substitution of larger Gd ions into the crystal lattice. Impedance spectroscopy analysis was performed under a wide range of frequency (f = 20 Hz-1 MHz) and temperature (T = 303-573 K). Electrical properties of Gd incorporated Co ferrite ceramics are enhanced compared to pure CoFe2O4 due to the lattice distortion. Impedance spectroscopic analysis illustrates the variation of bulk grain and grain-boundary contributions towards the electrical resistance and capacitance of CFGO materials with temperature. A two-layer heterogeneous model consisting of moderately conducting grain interior (ferrite-phase) regions separated by insulating grain boundaries (resistive-phase) accurately account for the observed temperature and frequency dependent electrical characteristic of CFGO ceramics.

  12. High Throughput Spectroscopic Catalyst Screening via Surface Plasmon Spectroscopy

    Science.gov (United States)

    2014-05-10

    transfer from the Pt to gold particles. Below we pictorially summarise how we have tried to use surface plasmon spectroscopy to study H2 interactions with...2014). 3. PI Mulvaney presented some of this work at an invied talk at the ACS Conference in Dallas in March 2014 and also to groups at

  13. Accurate spectroscopic characterization of protonated oxirane: a potential prebiotic species in Titan's atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Puzzarini, Cristina [Dipartimento di Chimica " Giacomo Ciamician," Università di Bologna, Via Selmi 2, I-40126 Bologna (Italy); Ali, Ashraf [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Biczysko, Malgorzata; Barone, Vincenzo, E-mail: cristina.puzzarini@unibo.it [Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa (Italy)

    2014-09-10

    An accurate spectroscopic characterization of protonated oxirane has been carried out by means of state-of-the-art computational methods and approaches. The calculated spectroscopic parameters from our recent computational investigation of oxirane together with the corresponding experimental data available were used to assess the accuracy of our predicted rotational and IR spectra of protonated oxirane. We found an accuracy of about 10 cm{sup –1} for vibrational transitions (fundamentals as well as overtones and combination bands) and, in relative terms, of 0.1% for rotational transitions. We are therefore confident that the spectroscopic data provided herein are a valuable support for the detection of protonated oxirane not only in Titan's atmosphere but also in the interstellar medium.

  14. High Throughput Spectroscopic Catalyst Screening via Surface Plasmon Spectroscopy

    Science.gov (United States)

    2015-07-15

    SPONSOR/MONITOR’S REPORT NUMBER(S) AOARD-144064 l#14IOA060 12. DISTRIBUTION/AVAILABILITY STATEMENT Distribution A: Approved for public...Techniques, Nanoparticles, Morphological Characterization, Defects 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT SAR 18. NUMBER OF...11. SPONSOR/MONITOR’S REPORT NUMBER(S) AOARD-144064 l#14IOA060 12. DISTRIBUTION/AVAILABILITY STATEMENT Approved for public release; distribution

  15. Surface characterization of platinum electrodes.

    Science.gov (United States)

    Solla-Gullón, José; Rodríguez, Paramaconi; Herrero, Enrique; Aldaz, Antonio; Feliu, Juan M

    2008-03-14

    The quantitative analysis of the different surface sites on platinum samples is attempted from pure voltammetric data. This analysis requires independent knowledge of the fraction of two-dimensional (111) and (100) domains. Specific site-probe reactions are employed to achieve this goal. Irreversibly-adsorbed bismuth and tellurium have been revealed to be sensitive to the presence of (111) terrace domains of different width whereas almost all sites involved in (100) ordered domains have been characterized through germanium adatoms. The experimental protocol follows that used with well-defined single-crystal electrodes and, therefore, requires careful control of the surface cleanliness. Platinum basal planes and their vicinal stepped surfaces have been employed to obtain calibration plots between the charge density measured under the adatom redox peak, specific for the type of surface site, and the corresponding terrace size. The evaluation of the (100) bidimensional domains can also be achieved using the voltammetric profiles, once the fraction of (111) ordered domains present in the polyoriented platinum has been determined and their featureless contribution has been subtracted from the whole voltammetric response. Using that curve, it is possible to perform a deconvolution of the adsorption states of the polycrystalline sample different from those related to (111) domains. The fraction of (100)-related states in the deconvoluted voltammogram can then be compared to that expected from the independent estimation coming from the charge involved in the redox process undergone by the irreversibly-adsorbed germanium and thus check the result of the deconvolution. The information about the surface-site distribution can also be applied to analyze the voltammetric profile of nanocrystalline platinum electrodes.

  16. In situ spectroscopic characterization of a terahertz resonant cavity

    DEFF Research Database (Denmark)

    Reichel, Kimberly S.; Iwaszczuk, Krzysztof; Jepsen, Peter Uhd;

    2014-01-01

    In many cases, the characterization of the frequency- dependent electric field profile inside a narrowband res- onator is challenging, either due to limited optical access or to the perturbative effects of invasive probes. An isolated groove inside a terahertz parallel-plate wave- guide provides ...

  17. Raman and surface enhanced Raman spectroscopic investigation on Lamiaceae plants

    Science.gov (United States)

    Rösch, P.; Popp, J.; Kiefer, W.

    1999-05-01

    The essential oils of Thymus vulgaris and Origanum vulgaris are studied by means of micro-Raman spectroscopy. The containing monoterpenes can be identified by their Raman spectra. Further the essential oils are investigated in their natural environment, the so-called oil cells of these Lamiaceae plants, with surface enhanced Raman spectroscopy (SERS). This method has the advantage to enhance Raman signals and furthermore the SERS effect leads to fluorescence quenching.

  18. Silicon Heterojunction Solar Cell Characterization and Optimization Using In Situ and Ex Situ Spectroscopic Ellipsometry: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Levi, D.; Iwaniczko, E.; Page, M.; Branz, H.; Wang, T.

    2006-05-01

    We use in-situ and ex-situ spectroscopic ellipsometry to characterize the optical, electronic, and structural properties of individual layers and completed silicon heterojunction devices. The combination of in-situ measurements during thin film deposition with ex-situ measurements of completed devices allows us to understand both the growth dynamics of the materials and the effects of each processing step on material properties. In-situ ellipsometry measurements enable us to map out how the optical properties change with deposition conditions, pointing the way towards reducing the absorption loss and increasing device efficiency. We use the measured optical properties and thickness of the i-, n-, and p-layers in optical device modeling to determine how the material properties affect device performance. Our best solar energy conversion efficiencies are 16.9% for a non-textured, single-sided device with an aluminum back surface field contact on a p-type float zone silicon wafer, and 17.8% for a textured double-sided device on a p-type float zone silicon wafer.

  19. Spectroscopic link between adsorption site occupation and local surface chemical reactivity

    DEFF Research Database (Denmark)

    Baraldi, A.; Lizzit, S.; Comelli, G.;

    2004-01-01

    In this Letter we show that sequences of adsorbate-induced shifts of surface core level (SCL) x-ray photoelectron spectra contain profound information on surface changes of electronic structure and reactivity. Energy shifts and intensity changes of time-lapsed spectral components follow simple...... rules, from which adsorption sites are directly determined. Theoretical calculations rationalize the results for transition metal surfaces in terms of the energy shift of the d-band center of mass and this proves that adsorbate-induced SCL shifts provide a spectroscopic measure of local surface...... reactivity....

  20. Application of Spectroscopic Ellipsometry and Mueller Ellipsometry to Optical Characterization

    CERN Document Server

    Garcia-Caurel, Enric; Gaston, Jean-Paul; Yan, Li

    2012-01-01

    This article aims to provide a brief overview of both established and novel ellipsometry techniques, as well as their applications. Ellipsometry is an indirect optical technique in that information about the physical properties of a sample is obtained through modeling analysis. Standard ellipsometry is typically used to characterize optically isotropic bulk and/or layered materials. More advanced techniques like Mueller ellipsometry, also known as polarimetry in literature, are necessary for the complete and accurate characterization of anisotropic and/or depolarizing samples which occur in many instances, both in research and "real life" activities. In this article we cover three main areas of subject: basic theory of polarization, standard ellipsometry and Mueller ellipsometry. Section I is devoted to a short and pedagogical introduction of the formalisms used to describe light polarization. The following section is devoted to standard ellipsometry. The focus is on the experimental aspects, including both p...

  1. Moessbauer spectroscopic, chemical and mineralogical characterization of Iberian Pottery

    OpenAIRE

    Ruíz García, Casilda

    1985-01-01

    Characterization of andent pottery is threefold: the provenance of the clay, non-plastics added and firing technology (kiln atmosphere and associated thermal cycle). Very often sherds of different provenance have similar appearance although, conversely, different manufacturing techniques can produce a wide variety of pottery from the sanle clay. Therefore a classification of the sherds based solely upan macroscopic and stylistic grounds could lead to serious mistakes. Physicoch...

  2. Electrical and spectroscopic characterization of a surgical argon plasma discharge

    Science.gov (United States)

    Keller, Sandra; Bibinov, Nikita; Neugebauer, Alexander; Awakowicz, Peter

    2013-01-01

    For electrosurgical procedures, the argon plasma coagulation (APC) discharge is a well-established atmospheric-pressure plasma tool for thermal haemostasis and devitalization of biological tissue. To characterize this plasma source, voltage-current measurements, microphotography, optical emission spectroscopy and numerical simulation are applied. Two discharge modes are established during the operation of the APC plasma source. A short transient spark discharge is ignited within the positive half period of the applied high voltage after a streamer channel connects the APC probe and the counter-electrode. During the second phase, which continues under negative high voltage, a glow discharge is stabilized in the plasma channel.

  3. Electrochemical and spectroscopic characterization of poly (bithiophene + 2-methylfuran) copolymer

    Science.gov (United States)

    Lamiri, Leila; Nessark, Belkacem; Habelhames, Farid; Sibous, Lakhdar

    2017-09-01

    In this work, Poly(bithiophene + 2-methylfuran) copolymer was successfully synthetized by an electrochemical polymerization of two monomers, bithiophene and 2-methylfuran in acetonitrile containing lithium perchlorate. The obtained copolymer was characterized via cyclic voltammetry, impedance spectroscopy, UV-visible, scanning electron microscope, conductivity and photocurrent measurements. The cyclic voltammetry study showed two redox couples characteristic of Poly (bithiophene + 2-methylfuran) copolymer. The impedance spectroscopy study revealed that the resistance of the copolymer film increases with the addition of 2-methylfuran. The photocurrent measurement showed good photoelectrochemical properties, making this copolymer an ideal candidate for photovoltaic cell applications.

  4. Simultaneous electronic and lattice characterization using coupled femtosecond spectroscopic techniques.

    Energy Technology Data Exchange (ETDEWEB)

    Beechem Iii, Thomas Edwin; Serrano, Justin Raymond; Hopkins, Patrick E

    2009-09-01

    High-power electronics are central in the development of radar, solid-state lighting, and laser systems. Large powers, however, necessitate improved heat dissipation as heightened temperatures deleteriously affect both performance and reliability. Heat dissipation, in turn, is determined by the cascade of energy from the electronic to lattice system. Full characterization of the transport then requires analysis of each. In response, this four-month late start effort has developed a transient thermoreflectance (TTR) capability that probes the thermal response of electronic carriers with 100 fs resolution. Simultaneous characterization of the lattice carriers with this electronic assessment was then investigated by equipping the optical arrangement to acquire a Raman signal from radiation discarded during the TTR experiment. Initial results show only tentative acquisition of a Raman response at these timescales. Using simulations of the response, challenges responsible for these difficulties are then examined and indicate that with outlined refinements simultaneous acquisition of TTR/Raman signals remains attainable in the near term.

  5. Simultaneous electronic and lattice characterization using coupled femtosecond spectroscopic techniques.

    Energy Technology Data Exchange (ETDEWEB)

    Beechem Iii, Thomas Edwin; Serrano, Justin Raymond; Hopkins, Patrick E

    2009-09-01

    High-power electronics are central in the development of radar, solid-state lighting, and laser systems. Large powers, however, necessitate improved heat dissipation as heightened temperatures deleteriously affect both performance and reliability. Heat dissipation, in turn, is determined by the cascade of energy from the electronic to lattice system. Full characterization of the transport then requires analysis of each. In response, this four-month late start effort has developed a transient thermoreflectance (TTR) capability that probes the thermal response of electronic carriers with 100 fs resolution. Simultaneous characterization of the lattice carriers with this electronic assessment was then investigated by equipping the optical arrangement to acquire a Raman signal from radiation discarded during the TTR experiment. Initial results show only tentative acquisition of a Raman response at these timescales. Using simulations of the response, challenges responsible for these difficulties are then examined and indicate that with outlined refinements simultaneous acquisition of TTR/Raman signals remains attainable in the near term.

  6. Synthesis and Spectroscopic Characterization of Two Tetrasubstituted Cationic Porphyrin Derivatives

    Directory of Open Access Journals (Sweden)

    Newton M. Barbosa Neto

    2011-07-01

    Full Text Available An imidazolium tetrasubstituted cationic porphyrin derivative (the free base and its Zn(II complex with five-membered heterocyclic groups in the meso-positions were synthesized using microwave irradiation, and the compounds obtained characterized by 1H-NMR and mass spectrometry. We observed that under microwave irradiation the yield is similar to when the synthesis is performed under conventional heating, however, the time required to prepare the porphyrins decreases enormously. In order to investigate the electronic state of these compounds, we employed UV-Vis and fluorescence spectroscopy combined with quantum chemical calculations. The results reveal the presence, in both compounds, of a large number of electronic states involving the association between the Soret and a blue-shifted band. The Soret band in both compounds also shows a considerable solvent dependence. As for emission, these compounds present low quantum yield at room temperature and no solvent influence on the fluorescence spectra was observed.

  7. Infrared Spectroscopic Characterization of Calcium and Barium Hydrazone Complexes

    Directory of Open Access Journals (Sweden)

    *A. Adeniyi

    2013-06-01

    Full Text Available Hydrazones have attracted considerable interest on account of their biological activities. Introduction of calcium and barium metal ions into m- and p-nitrobenzoic hydrazones is expected to modify these biological properties for enhanced activity and versatility. The ligands were synthesized from the parent acids. The complexes have been characterized using C, H and N microanalyses and IR spectrometry. The IR spectral data of the ligands and complexes revealed bonding via the C=O and C=N groups. The suggested metal to ligand stoichiometries are: [M (m-NBHx]Cl2.yH2O, x, y = 1 and 4 for M = Ca; x, y = 2 and 3 for M = Ba respectively. [M(p-NBHx]Cl2.yH2O, x, y = 1 and 12 for M = Ca; x, y = 1 and 3 for M = Ba respectively. The structural deductions are tentative pending future X-ray structural studies.

  8. Characterization of Sorolla's gouache pigments by means of spectroscopic techniques

    Science.gov (United States)

    Roldán, Clodoaldo; Juanes, David; Ferrazza, Livio; Carballo, Jorgelina

    2016-02-01

    This paper presents the characterization of the Joaquín Sorolla's gouache sketches for the oil on canvas series "Vision of Spain" commissioned by A. M. Huntington to decorate the library of the Hispanic Society of America in New York. The analyses were focused on the identification of the elemental composition of the gouache pigments by means of portable EDXRF spectrometry in a non-destructive mode. Additionally, SEM-EDX and FTIR analyses of a selected set of micro-samples were carried out to identify completely the pigments, the paint technique and the binding media. The obtained results have confirmed the identification of lead and zinc white, vermillion, earth pigments, ochre, zinc yellow, chrome yellow, ultramarine, Prussian blue, chromium based and copper-arsenic based green pigments, bone black and carbon based black pigments, and the use of gum arabic as binding media in the gouache pigments.

  9. Spectroscopic Characterizations of the DIII--D Divertor

    Science.gov (United States)

    Isler, R. C.; Klepper, C. C.; Wood, R. D.; Fenstermacher, M. E.; Leonard, A. W.

    1996-11-01

    Radiative losses from the DIII--D divertor have been characterized for various types of discharges by making extensive use of vacuum ultraviolet spectral lines in conjunction with a collisional-radiative model. Carbon and hydrogen account for essentially all the emission with the carbon fraction usually between 50% and 80% of the total. Ion densities are estimated from a simplified approach to modeling using a one-dimensional transport code. The concentrations range from 2%--6% of the electron density in partially detached plasmas, but it appears that carbon may supply most of the electrons in the divertor in attached plasmas. Ion temperatures are measured from Doppler broadening of spectral lines after accounting precisely for the Zeeman/Paschen-Back effect. In general, the ion temperatures agree well with the electron temperatures at the location of the radiating ions as deduced from spectral line ratio measurements and from the modeling.

  10. Spectroscopic characterization of atmospheric pressure um-jet plasma source

    CERN Document Server

    Bibinov, Nikita; Bahre, Hendrik; Awakowicz, Peter; der Gathen, Volker Schulz-von

    2011-01-01

    A radio frequency um-jet plasma source is studied using He/O2 mixture. This um-jet can be used for different applications as a source of chemical active species e.g. oxygen atoms, molecular metastables and ozone. Using absolutely-calibrated optical emission spectroscopy and numerical simulation, the gas temperature in active plasma region and plasma parameters (electron density and electron distribution function) are determined. Concentrations of oxygen atoms and ozone in the plasma channel and in the effluent of the plasma source are measured using emission and absorption spectroscopy. To interpret the measured spatial distributions, the steady-state species' concentrations are calculated using determined plasma parameters and gas temperature. At that the influence of the surface processes and gas flow regime on the loss of the active species in the plasma source are discussed. The measured spatial distributions of oxygen atom and ozone densities are compared with the simulated ones.

  11. Spectroscopic characterization of bioactive carboxyamide with trinuclear lanthanide (III) ions

    Science.gov (United States)

    Singh, Bibhesh K.; Prakash, Anant; Adhikari, Devjani

    2009-10-01

    Complexes of La(III), Sm(III), Eu(III) and Tb(III) with bioactive carboxyamide ligands N',N″-bis(3-caboxy-1-oxophenelenyl)2-amino-N-arylbenzamidine have been synthesized and characterized by various physico-chemical techniques. Mass spectrum explains the successive degradation of the molecular species in solution and justifies ML complexes. Vibrational spectra indicate coordination of Ln(III) with amide and carboxylate oxygen of the ligand along with nitrate ions. The magnetic moment of Sm(III) and Eu(III) complexes showed slightly higher-values which originated due to low J- J separation leading to thermal population of next higher energy J levels and susceptibility due to first order Zeeman effect. The strong luminescence emitting peaks at 587 nm for Eu(III) and 543 nm for Tb(III) can be observed, which could be attributed to the ligand have an enhanced effect to the luminescence intensity of the Eu(III) and Tb(III). The thermal behaviour of complexes shows that water molecules and nitrate ion are removed in first step followed by the removal of two molecules of nitrate ions and then decomposition of the ligand molecule in subsequent step. Kinetic and thermodynamic parameters were computed from the thermal data using Coats and Redferm method, which confirm first order kinetics.

  12. Spectroscopic and morphologic characterization of the dentin/adhesive interface

    Science.gov (United States)

    Lemor, R. M.; Kruger, Michael B.; Wieliczka, David M.; Swafford, Jim R.; Spencer, Paulette

    1999-01-01

    The potential environmental risks associated with mercury release have forced many European countries to ban the use of dental amalgam. Alternative materials such as composite resins do not provide the clinical function for the length of time characteristically associated with dental amalgam. The weak link in the composite restoration is the dentin/adhesive bond. The purpose of this study was to correlate morphologic characterization of the dentin/adhesive bond with chemical analyses using micro- Fourier transform infrared and micro-Raman spectroscopy. A commercial dental adhesive was placed on dentin substrates cut from extracted, unerupted human third molars. Sections of the dentin/adhesive interface were investigated using infrared radiation produced at the Aladdin synchrotron source; visible radiation from a Kr+ laser was used for the micro-Raman spectroscopy. Sections of the dentin/adhesive interface, differentially stained to identify protein, mineral, and adhesive, were examined using light microscopy. Due to its limited spatial resolution and the unknown sample thickness the infrared results cannot be used quantitatively in determining the extent of diffusion. The results from the micro-Raman spectroscopy and light microscopy indicate exposed protein at the dentin/adhesive interface. Using a laser that reduces background fluorescence, the micro-Raman spectroscopy provides quantitative chemical and morphologic information on the dentin/adhesive interface. The staining procedure is sensitive to sites of pure protein and thus, complements the Raman results.

  13. Synthesis, characterization, and spectroscopic investigation of benzoxazole conjugated Schiff bases.

    Science.gov (United States)

    Santos, Fabiano S; Costa, Tania M H; Stefani, Valter; Gonçalves, Paulo F B; Descalzo, Rodrigo R; Benvenutti, Edilson V; Rodembusch, Fabiano S

    2011-11-24

    Two Schiff bases were synthesized by reaction of 2-(4'-aminophenyl)benzoxazole derivatives with 4-N,N-diethylaminobenzaldehyde. UV-visible (UV-vis) and steady-state fluorescence in solution were applied in order to characterize its photophysical behavior. The Schiff bases present absorption in the UV region with fluorescence emission in the blue-green region, with a large Stokes' shift. The UV-vis data indicates that each dye behaves as two different chromophores in solution in the ground state. The fluorescence emission spectra of the dye 5a show that an intramolecular proton transfer (ESIPT) mechanism takes place in the excited state, whereas a twisted internal charge transfer (TICT) state is observed for the dye 5b. Theoretical calculations were performed in order to study the conformation and polarity of the molecules at their ground and excited electronic states. Using density functional theory (DFT) methods at theoretical levels BLYP/Aug-SV(P) for geometry optimizations and B3LYP/6-311++G(2d,p) for single-point energy evaluations, the calculations indicate that the lowest energy conformations are in all cases nonplanar and that the dipole moments of the excited state relaxed structures are much larger than those of the ground state structures, which corroborates the experimental UV-vis absorption results.

  14. Spectroscopic characterization of the DIII-D divertor

    Science.gov (United States)

    Isler, R. C.; Wood, R. W.; Klepper, C. C.; Brooks, N. H.; Fenstermacher, M. E.; Leonard, A. W.

    1997-02-01

    Radiative losses along a fixed view into the divertor chamber of the DIII-D tokamak [Plasma Physics Controlled Nuclear Fusion Research 1986 (International Atomic Energy Agency, Vienna, 1987), Vol I, p. 159] have been characterized for attached and partially detached discharges by analyzing line-integrated vacuum ultraviolet (VUV) signals. Essentially all the emission can be ascribed to carbon and deuterium. Because the majority of the most intense lines, which lie at wavelengths above 1100 Å, are not accessible to the present instrumentation, extensive use has been made of collisional-radiative (CR) calculations for level populations of the important ions in order to relate the total radiated power to shorter wavelength transitions. In beam-heated plasmas, the fraction of radiation detected from carbon along the VUV spectrometer view is usually between 50% and 80% of the total. Carbon densities are estimated from a simplified approach to modelling the emission using a one-dimensional transport code. For partially detached plasmas the concentrations range from 2%-6% of the electron density; but in attached plasmas it appears that carbon may supply most of the electrons in the divertor region just below the X point. Ion temperatures are measured from Doppler broadening of spectral lines by fitting measured profiles to theoretical lineshapes, which account precisely for atomic sublevel splitting caused by the Zeeman/Paschen-Back effect in the tokamak magnetic field.

  15. Nanoprecipitation and Spectroscopic Characterization of Curcumin-Encapsulated Polyester Nanoparticles.

    Science.gov (United States)

    Leung, Mandy H M; Harada, Takaaki; Dai, Sheng; Kee, Tak W

    2015-10-27

    Curcumin-encapsulated polyester nanoparticles (Cur-polyester NPs) of approximately 100 nm diameter with a negatively charged surface were prepared using a one-step nanoprecipitation method. The Cur-polyester NPs were prepared using polylactic acid, poly(D,L-lactic-co-glycolic acid) and poly(ϵ-caprolactone) without any emulsifier or surfactant. The encapsulation of curcumin in these polyester NPs greatly suppresses curcumin degradation in the aqueous environment due to its segregation from water. In addition, the fluorescence of curcumin in polyester NPs has a quantum yield of 4 to 5%, which is higher than that of curcumin in micellar systems and comparable to those in organic solvents, further supporting the idea that the polyester NPs are capable of excluding water from curcumin. Furthermore, the results from femtosecond fluorescence upconversion spectroscopy reveal that there is a decrease in the signal amplitude corresponding to solvent reorganization of excited state curcumin in the polyester NPs compared with curcumin in micellar systems. The Cur-polyester NPs also show a lack of deuterium isotope effect in the fluorescence lifetime. These results indicate that the interaction between curcumin and water in the polyester NPs is significantly weaker than that in micelles. Therefore, the aqueous stability of curcumin is greatly improved due to highly effective segregation from water. The overall outcome suggests that the polyester NPs prepared using the method reported herein are an attractive system for encapsulating and stabilizing curcumin in the aqueous environment.

  16. Optical spectroscopic characterizations of laser irradiated olivine grains

    Science.gov (United States)

    Yang, Yazhou; Zhang, Hao; Wang, Ziwei; Yuan, Ye; Li, Shaolin; Hsu, Weibiao; Liu, Chujian

    2017-01-01

    Context. Visible and near-infrared spectra of asteroids are known to be susceptible to nanophase irons produced by space weathering processes, thus making mineral identifications difficult. Mid-infrared spectroscopy may retain more mineral features owing to its lattice vibrational nature. Aims: We investigate the structure and reflectance spectral feature changes of olivine grains before and after simulated space weathering. Methods: We irradiate olivine grains by using pulsed laser to simulate varying degrees of micrometeorite bombardments. Reflectance measurements from 0.5 to 25 μm and radiative transfer calculations were carried out in order to compare them with each other. Results: Both the experimental simulations and modeling results indicate that the mid-infrared spectral features of olivine grains can survive the intense irradiations. Although the Christansen Feature is slightly shifted to longer wavelength, major vibrational bands remain essentially unchanged, because the lattice structure is quite immune to even the strongest irradiations, as revealed by both the X-ray diffraction and Raman scattering measurements. Conclusions: Mid-infrared spectroscopy is much more immune to productions of nanophase irons and amorphous materials and thus may be used more reliably in remote detections of minerals on asteroid surfaces.

  17. Synthesis and spectroscopic characterization of copper zinc aluminum nanoferrite particles

    Science.gov (United States)

    Lakshmi Reddy, S.; Ravindra Reddy, T.; Roy, Nivya; Philip, Reji; Montero, Ovidio Almanza; Endo, Tamio; Frost, Ray L.

    2014-06-01

    Copper doped zinc aluminum ferrites CuxZn1-x.(AlxFe2-x)O4 are synthesized by the solid-state reaction route and characterized by XRD, TEM, EPR and non linear optical spectroscopy techniques. The average particle size is found to be from 35 to 90 nm and the unit cell parameter “a” is calculated as from 8.39 to 8.89 Å. The cation distributions are estimated from X-ray diffraction intensities of various planes. The XRD studies have verified the quality of the synthesis of compounds and have shown the differences in the positions of the diffraction peaks due to the change in concentration of copper ions. TEM pictures clearly indicating that fundamental unit is composed of octahedral and tetrahedral blocks and joined strongly. The selected area electron diffraction (SAED) of the ferrite system shows best crystallinity is obtained when Cu content is very. Some of the d-plane spacings are exactly coinciding with XRD values. EPR spectra is compositional dependent at lower Al/Cu concentration EPR spectra is due to Fe3+ and at a higher content of Al/Cu the EPR spectra is due to Cu2+. Absence of EPR spectra at room temperature indicates that the sample is perfectly ferromagnetic. EPR results at low temperature indicate that the sample is paramagnetic, and that copper is placed in the tetragonal elongation (B) site with magnetically non-equivalent ions in the unit cell having strong exchange coupling between them. This property is useful in industrial applications. Nonlinear optical properties of the samples studied using 5 ns laser pulses at 532 nm employing the open aperture z-scan technique indicate that these ferrites are potential candidates for optical limiting applications.

  18. Characterization of porcine skin as a model for human skin studies using infrared spectroscopic imaging.

    Science.gov (United States)

    Kong, Rong; Bhargava, Rohit

    2011-06-07

    Porcine skin is often considered a substitute for human skin based on morphological and functional data, for example, for transdermal drug diffusion studies. A chemical, structural and temporal characterization of porcine skin in comparison to human skin is not available but will likely improve our understanding of this porcine skin model. Here, we employ Fourier transform infrared (FT-IR) spectroscopic imaging to holistically measure chemical species as well as spatial structure as a function of time to characterize porcine skin as a model for human skin. Porcine skin was found to resemble human skin spectroscopically and differences are elucidated. Cryo-prepared fresh porcine skin samples for spectroscopic imaging were found to be stable over time and small variations are observed. Hence, we extended characterization to the use of this model for dynamic processes. In particular, the capacity and stability of this model in transdermal diffusion is examined. The results indicate that porcine skin is likely to be an attractive tool for studying diffusion dynamics of materials in human skin.

  19. 13C Solid State Nuclear Magnetic Resonance and µ-Raman Spectroscopic Characterization of Sicilian Amber.

    Science.gov (United States)

    Barone, Germana; Capitani, Donatella; Mazzoleni, Paolo; Proietti, Noemi; Raneri, Simona; Longobardo, Ugo; Di Tullio, Valeria

    2016-08-01

    (13)C cross-polarization magic angle spinning (CPMAS) nuclear magnetic resonance (NMR) and µ-Raman spectroscopy were applied to characterize Sicilian amber samples. The main goal of this work was to supply a complete study of simetite, highlighting discriminating criteria useful to distinguish Sicilian amber from fossil resins from other regions and laying the foundations for building a spectroscopic database of Sicilian amber. With this aim, a private collection of unrefined simetite samples and fossil resins from the Baltic region and Dominican Republic was analyzed. Overall, the obtained spectra permitted simetite to be distinguished from the other resins. In addition, principal component analysis (PCA) was applied to the spectroscopic data, allowing the clustering of simetite samples with respect to the Baltic and Dominican samples and to group the simetite samples in two sets, depending on their maturity. Finally, the analysis of loadings allowed for a better understanding of the spectral features that mainly influenced the discriminating characteristics of the investigated ambers.

  20. Chromate adsorption on selected soil minerals: Surface complexation modeling coupled with spectroscopic investigation

    Energy Technology Data Exchange (ETDEWEB)

    Veselská, Veronika, E-mail: veselskav@fzp.czu.cz [Department of Environmental Geosciences, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcka 129, CZ-16521, Prague (Czech Republic); Fajgar, Radek [Department of Analytical and Material Chemistry, Institute of Chemical Process Fundamentals of the CAS, v.v.i., Rozvojová 135/1, CZ-16502, Prague (Czech Republic); Číhalová, Sylva [Department of Environmental Geosciences, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcka 129, CZ-16521, Prague (Czech Republic); Bolanz, Ralph M. [Institute of Geosciences, Friedrich-Schiller-University Jena, Carl-Zeiss-Promenade 10, DE-07745, Jena (Germany); Göttlicher, Jörg; Steininger, Ralph [ANKA Synchrotron Radiation Facility, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, DE-76344, Eggenstein-Leopoldshafen (Germany); Siddique, Jamal A.; Komárek, Michael [Department of Environmental Geosciences, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcka 129, CZ-16521, Prague (Czech Republic)

    2016-11-15

    Highlights: • Study of Cr(VI) adsorption on soil minerals over a large range of conditions. • Combined surface complexation modeling and spectroscopic techniques. • Diffuse-layer and triple-layer models used to obtain fits to experimental data. • Speciation of Cr(VI) and Cr(III) was assessed. - Abstract: This study investigates the mechanisms of Cr(VI) adsorption on natural clay (illite and kaolinite) and synthetic (birnessite and ferrihydrite) minerals, including its speciation changes, and combining quantitative thermodynamically based mechanistic surface complexation models (SCMs) with spectroscopic measurements. Series of adsorption experiments have been performed at different pH values (3–10), ionic strengths (0.001–0.1 M KNO{sub 3}), sorbate concentrations (10{sup −4}, 10{sup −5}, and 10{sup −6} M Cr(VI)), and sorbate/sorbent ratios (50–500). Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy were used to determine the surface complexes, including surface reactions. Adsorption of Cr(VI) is strongly ionic strength dependent. For ferrihydrite at pH <7, a simple diffuse-layer model provides a reasonable prediction of adsorption. For birnessite, bidentate inner-sphere complexes of chromate and dichromate resulted in a better diffuse-layer model fit. For kaolinite, outer-sphere complexation prevails mainly at lower Cr(VI) loadings. Dissolution of solid phases needs to be considered for better SCMs fits. The coupled SCM and spectroscopic approach is thus useful for investigating individual minerals responsible for Cr(VI) retention in soils, and improving the handling and remediation processes.

  1. Spectroscopic study on variations in illite surface properties after acid-base titration

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    FT-IR, Raman microscopy, XRD, 29 Si and 27 Al MAS NMR, were used to investigate changes in surface properties of a natural illitesample after acid-base potentiometric titration. The characteristic XRD lines indicated the presence of surface Al-Si complexes, preferable to Al(OH)3 precipitates. In the microscopic Raman spectra, the vibration peaks of Si-O and Al-O bonds diminished as a result of treatment withacid, then increased after hydroxide back titration. The varied ratio of signal intensity between Ⅳ Al and Ⅵ At species in 27 Al MAS NMRspectra, together with the stable BET surface area after acidimetric titration, suggested that edge faces and basal planes in the layer structure ofillite participated in dissolution of structural components. The combined spectroscopic evidence demonstrated that the reactions between illitesurfaces and acid-leaching silicic acid and aluminum ions should be considered in the model description of surface acid-base properties of theaqueous illite.

  2. Synthesis, spectroscopic characterizations, crystal structures and DFT studies of nalidixic acid carbonyl hydrazones derivatives

    Science.gov (United States)

    Bergamini, F. R. G.; Ribeiro, M. A.; Lancellotti, M.; Machado, D.; Miranda, P. C. M. L.; Cuin, A.; Formiga, A. L. B.; Corbi, P. P.

    2016-09-01

    This article describes the synthesis and characterization of the 1-ethyl-7-methyl-4-oxo-1,4-dihydro-1,8-naphthyridine-3-carbohydrazide (hzd) and six carbonyl hydrazones derivatives of the nalidixic with 1H-pyrrol-2-ylmethylidene (hpyrr), 1H-imidazol-2-ylmethylidene (h2imi), pyridin-2-ylmethylidene (h2py), pyridin-3-ylmethylidene (h3py), pyridin-4-ylmethylidene(h4py) and (2-hydroxyphenyl)methylidene (hsali). The carbonyl hydrazones were characterized by elemental and ESI-QTOF-MS analyses, IR and detailed NMR spectroscopic measurements. The 2D NMR experiments allowed the unambiguous assignment of the hydrogen, carbon and nitrogen atoms, which have not been reported for nalidixic acid carbonyl hydrazone derivatives so far. Crystal structures of hzd and the new carbonyl hydrazones h2imi, hpyrr and h3py were determined by X-ray diffraction studies. Although the synthesis of hzd was reported decades ago, the hzd crystal structure have not been reported yet. Geometric optimizations of all the characterized structures were performed with the aid of DFT studies. Despite the fact that the hydrazones with 2-pyridine carboxylic acid (h2py) and salicyl aldehyde (hsali) were already reported by literature, a detailed spectroscopic study followed by DFT studies are also reported for such compounds in this manuscript. Antimicrobial studies of the compounds are also presented.

  3. Spectroscopic characterization of both aqueous and solid-state diacerhein/hydroxypropyl-β-cyclodextrin inclusion complexes

    Science.gov (United States)

    Petralito, Stefania; Zanardi, Iacopo; Spera, Romina; Memoli, Adriana; Travagli, Valter

    2014-06-01

    Diacerhein, a poorly water soluble antirheumatic prodrug, was spectroscopically characterized to form inclusion complexes with hydroxypropyl-β-cyclodextrin (HPβCD) in both aqueous solution and in solid phase. Complexation with the hydrophilic carriers was used to improve the solubility and dissolution rate of the compound. The kinetics of the prodrug degradation to the active rhein in aqueous buffer solution were also investigated as a function of HPβCD concentration. The solid complexes prepared by different methods such as physical mixture, kneading, co-evaporation method and freeze dried method in 1:1 M ratio, were characterized by DSC and FTIR. The dissolution profiles of solid complexes were determined and compared with diacerhein alone and their physical mixture, in the simulated intestinal fluid at 37 °C. The accurate molecular spectroscopic characterization of diacerhein in the presence of different amounts of aqueous cyclodextrins was essential to determine the correct binding constants for the diacerhein/HPβCD system. The binding constants were also validated by UV spectrometry and HPLC procedure in order to compare the values from the different methods. Higuchi-Connors phase solubility method has proved not suitable when either the free or/and the complexed prodrug degrade in aqueous solution.

  4. Synthesis and spectroscopic characterization of Yb3+ in Ca1-XYbXF2+X crystals

    Science.gov (United States)

    Ito, M.; Goutaudier, C.; Guyot, Y.; Lebbou, K.; Fukuda, T.; Boulon, G.

    2004-11-01

    Ca1-XYbXF2+X crystals were grown by two different methods: simple melting under CF{4} atmosphere and laser heated pedestal growth (LHPG) method under Ar atmosphere. Spectroscopic characterization has been carried out to separate different crystallographic site in Ca1-XYbXF2+X crystals and to identify Stark's levels of Yb3+ transitions. Experimental decay time dependence of Yb3+ concentration was analyzed by using concentration gradient fiber in order to understand concentration quenching mechanisms. Energy transfer to unexpected rare earth impurities observed by up-conversion emission spectra in visible region under IR Yb3+ ion pumping seems to be an efficient process.

  5. Quantitative surface characterization using a Nomarski microscope

    NARCIS (Netherlands)

    Brug, H. van; Booij, S.M.; Fähnle, O.W.; Bijl, R.J.M. van der

    2000-01-01

    The use of a Nomarski microscope for the characterization of surface features will be presented. Since a Nomarski microscope measures slope values, the shape of a surface can be followed quantitatively. Besides, a Nomarski microscope can be used to analyze surface roughness in terms of rms value and

  6. New Surface Brightness Fluctuations Spectroscopic Technique: NGC4449 and its Stellar Tidal Stream

    CERN Document Server

    Toloba, Elisa; Romanowsky, Aaron; Brodie, Jean; Martinez-Delgado, David; Arnold, Jacob; Ramachandran, Neel; Theakanath, Kuriakose

    2016-01-01

    We present a new spectroscopic technique based in part on targeting the upward fluctuations of the surface brightness for studying the internal stellar kinematics and metallicities of low surface brightness galaxies and streams beyond the Local Group. The distance to these systems makes them unsuitable for targeting individual red giant branch (RGB) stars (tip of RGB at $I\\gtrsim24$~mag) and their surface brightness is too low ($\\mu_r\\gtrsim 25$~mag~arcsec$^{-2}$) for integrated light spectroscopic measurements. This technique overcomes these two problems by targeting individual objects that are brighter than the tip of the RGB. We apply this technique to the star-forming dwarf galaxy NGC 4449 and its stellar stream. We use Keck/DEIMOS data to measure the line-of-sight radial velocity out to $\\sim7$~kpc in the East side of the galaxy and $\\sim8$~kpc along the stream. We find that the two systems are likely gravitationally bound to each other and have heliocentric radial velocities of $227.3\\pm10.7$~km/s and $...

  7. Radioactive Ions for Surface Characterization

    CERN Multimedia

    2002-01-01

    The collaboration has completed a set of pilot experiments with the aim to develop techniques for using radioactive nuclei in surface physics. The first result was a method for thermal deposition of isolated atoms (Cd, In, Rb) on clean metallic surfaces. \\\\ \\\\ Then the diffusion history of deposited Cd and In atoms on two model surfaces, Mo(110) and Pd(111), was followed through the electric field gradients (efg) acting at the probe nuclei as measured with the Perturbed Angular Correlation technique. For Mo(110) a rather simple history of the adatoms was inferred from the experiments: Atoms initially landing at terrace sites diffuse from there to ledges and then to kinks, defects always present at real surfaces. The next stage is desorption from the surface. For Pd a scenario that goes still further was found. Following the kink stage the adatoms get incorporated into ledges and finally into the top surface layer. For all these five sites the efg's could be measured.\\\\ \\\\ In preparation for a further series o...

  8. Surfaces. [characterization of surface properties for predicting bond quality

    Science.gov (United States)

    Buckley, D. H.

    1983-01-01

    Techniques for the characterization of surface cleanliness and roughness for predicting the quality of an adhesive bond are outlined. Generally, smooth surfaces are only available from cleavage of crystalline materials along a natural cleavage plane. Films must be deposited on metal surfaces to achieve the same smoothness. Once the surfaces are clean, however, reaction with the ambient atmosphere becomes likely through diffusive and absorption processes, producing asperities. Electron diffraction, Auger electron, and X ray emission spectroscopy are used to characterize surface condition. Once the surface is observed to be clean, the application of an adhesive will usually prohibit separation along the adhesive; separation is then confined to the weaker of the two materials. Finally, the use of polytetrafluorothylene adhesive to test the adhesion between polymers and metal surfaces is described.

  9. Enhanced Characterization of Niobium Surface Topography

    Energy Technology Data Exchange (ETDEWEB)

    Chen Xu, Hui Tian, Charles Reece, Michael Kelley

    2011-12-01

    Surface topography characterization is a continuing issue for the Superconducting Radio Frequency (SRF) particle accelerator community. Efforts are underway to both to improve surface topography, and its characterization and analysis using various techniques. In measurement of topography, Power Spectral Density (PSD) is a promising method to quantify typical surface parameters and develop scale-specific interpretations. PSD can also be used to indicate how chemical processes modifiesy the roughnesstopography at different scales. However, generating an accurate and meaningful topographic PSD of an SRF surface requires careful analysis and optimization. In this report, polycrystalline surfaces with different process histories are sampled with AFM and stylus/white light interferometer profilometryers and analyzed to indicate trace topography evolution at different scales. evolving during etching or polishing. Moreover, Aan optimized PSD analysis protocol will be offered to serve the SRF surface characterization needs is presented.

  10. Spectroscopic, Electrochemical, and In Silico Characterization of Complex Formed between 2-Ferrocenylbenzoic Acid and DNA

    Directory of Open Access Journals (Sweden)

    Ataf Ali Altaf

    2016-01-01

    Full Text Available We present the synthesis of 2-ferrocenylbenzoic acid (FcOH and its electrochemical and spectroscopic characterization. FcOH was characterized for interaction with DNA using theoretical and experimental methods. UV-visible spectroscopy and cyclic voltammeter (CV were used for the experimental account of FcOH-DNA complex. The experimental results showed that the FcOH interacts by electrostatic mode. The binding constant (Kb and Gibbs free energy (ΔG for the FcOH-DNA complex have been estimated as 5.3 × 104 M−1 and −6.44 kcal/mol, respectively. The theoretical DNA binding of FcOH was studied with AutoDock molecular docking software. The docking studies yield good approximation with experimental data and explain the sites of binding.

  11. Quantitative Ultrasound Spectroscopic Imaging for Characterization of Disease Extent in Prostate Cancer Patients1

    Science.gov (United States)

    Sadeghi-Naini, Ali; Sofroni, Ervis; Papanicolau, Naum; Falou, Omar; Sugar, Linda; Morton, Gerard; Yaffe, Martin J.; Nam, Robert; Sadeghian, Alireza; Kolios, Michael C.; Chung, Hans T.; Czarnota, Gregory J.

    2015-01-01

    Three-dimensional quantitative ultrasound spectroscopic imaging of prostate was investigated clinically for the noninvasive detection and extent characterization of disease in cancer patients and compared to whole-mount, whole-gland histopathology of radical prostatectomy specimens. Fifteen patients with prostate cancer underwent a volumetric transrectal ultrasound scan before radical prostatectomy. Conventional-frequency (~ 5 MHz) ultrasound images and radiofrequency data were collected from patients. Normalized power spectra were used as the basis of quantitative ultrasound spectroscopy. Specifically, color-coded parametric maps of 0-MHz intercept, midband fit, and spectral slope were computed and used to characterize prostate tissue in ultrasound images. Areas of cancer were identified in whole-mount histopathology specimens, and disease extent was correlated to that estimated from quantitative ultrasound parametric images. Midband fit and 0-MHz intercept parameters were found to be best associated with the presence of disease as located on histopathology whole-mount sections. Obtained results indicated a correlation between disease extent estimated noninvasively based on midband fit parametric images and that identified histopathologically on prostatectomy specimens, with an r2 value of 0.71 (P < .0001). The 0-MHz intercept parameter demonstrated a lower level of correlation with histopathology. Spectral slope parametric maps offered no discrimination of disease. Multiple regression analysis produced a hybrid disease characterization model (r2 = 0.764, P < .05), implying that the midband fit biomarker had the greatest correlation with the histopathologic extent of disease. This work demonstrates that quantitative ultrasound spectroscopic imaging can be used for detecting prostate cancer and characterizing disease extent noninvasively, with corresponding gross three-dimensional histopathologic correlation. PMID:25749174

  12. Quantitative Ultrasound Spectroscopic Imaging for Characterization of Disease Extent in Prostate Cancer Patients

    Directory of Open Access Journals (Sweden)

    Ali Sadeghi-Naini

    2015-02-01

    Full Text Available Three-dimensional quantitative ultrasound spectroscopic imaging of prostate was investigated clinically for the noninvasive detection and extent characterization of disease in cancer patients and compared to whole-mount, whole-gland histopathology of radical prostatectomy specimens. Fifteen patients with prostate cancer underwent a volumetric transrectal ultrasound scan before radical prostatectomy. Conventional-frequency (~5 MHz ultrasound images and radiofrequency data were collected from patients. Normalized power spectra were used as the basis of quantitative ultrasound spectroscopy. Specifically, color-coded parametric maps of 0-MHz intercept, midband fit, and spectral slope were computed and used to characterize prostate tissue in ultrasound images. Areas of cancer were identified in whole-mount histopathology specimens, and disease extent was correlated to that estimated from quantitative ultrasound parametric images. Midband fit and 0-MHz intercept parameters were found to be best associated with the presence of disease as located on histopathology whole-mount sections. Obtained results indicated a correlation between disease extent estimated noninvasively based on midband fit parametric images and that identified histopathologically on prostatectomy specimens, with an r2 value of 0.71 (P < .0001. The 0-MHz intercept parameter demonstrated a lower level of correlation with histopathology. Spectral slope parametric maps offered no discrimination of disease. Multiple regression analysis produced a hybrid disease characterization model (r2 = 0.764, P < .05, implying that the midband fit biomarker had the greatest correlation with the histopathologic extent of disease. This work demonstrates that quantitative ultrasound spectroscopic imaging can be used for detecting prostate cancer and characterizing disease extent noninvasively, with corresponding gross three-dimensional histopathologic correlation.

  13. Quantitative ultrasound spectroscopic imaging for characterization of disease extent in prostate cancer patients.

    Science.gov (United States)

    Sadeghi-Naini, Ali; Sofroni, Ervis; Papanicolau, Naum; Falou, Omar; Sugar, Linda; Morton, Gerard; Yaffe, Martin J; Nam, Robert; Sadeghian, Alireza; Kolios, Michael C; Chung, Hans T; Czarnota, Gregory J

    2015-02-01

    Three-dimensional quantitative ultrasound spectroscopic imaging of prostate was investigated clinically for the noninvasive detection and extent characterization of disease in cancer patients and compared to whole-mount, whole-gland histopathology of radical prostatectomy specimens. Fifteen patients with prostate cancer underwent a volumetric transrectal ultrasound scan before radical prostatectomy. Conventional-frequency (~5MHz) ultrasound images and radiofrequency data were collected from patients. Normalized power spectra were used as the basis of quantitative ultrasound spectroscopy. Specifically, color-coded parametric maps of 0-MHz intercept, midband fit, and spectral slope were computed and used to characterize prostate tissue in ultrasound images. Areas of cancer were identified in whole-mount histopathology specimens, and disease extent was correlated to that estimated from quantitative ultrasound parametric images. Midband fit and 0-MHz intercept parameters were found to be best associated with the presence of disease as located on histopathology whole-mount sections. Obtained results indicated a correlation between disease extent estimated noninvasively based on midband fit parametric images and that identified histopathologically on prostatectomy specimens, with an r(2) value of 0.71 (P<.0001). The 0-MHz intercept parameter demonstrated a lower level of correlation with histopathology. Spectral slope parametric maps offered no discrimination of disease. Multiple regression analysis produced a hybrid disease characterization model (r(2)=0.764, P<.05), implying that the midband fit biomarker had the greatest correlation with the histopathologic extent of disease. This work demonstrates that quantitative ultrasound spectroscopic imaging can be used for detecting prostate cancer and characterizing disease extent noninvasively, with corresponding gross three-dimensional histopathologic correlation. Copyright © 2014 Neoplasia Press, Inc. Published by

  14. Traceable surface characterization using replica moulding technology

    DEFF Research Database (Denmark)

    Gasparin, Stefania; Hansen, Hans Nørgaard; Tosello, Guido

    2011-01-01

    Characterization of ultra-finely finished surfaces (e.g. mirrored surfaces or polished specimens) is nowadays challenging due to possible part damage if a contact instrument is used or due to scattered light if the measurements are performed with optical instruments. In order to prevent these pro...

  15. Fractal characterization of fracture surfaces in concrete

    Science.gov (United States)

    Saouma, V.E.; Barton, C.C.; Gamaleldin, N.A.

    1990-01-01

    Fractal geometry is used to characterize the roughness of cracked concrete surfaces through a specially built profilometer, and the fractal dimension is subsequently correlated to the fracture toughness and direction of crack propagation. Preliminary results indicate that the fracture surface is indeed fractal over two orders of magnitudes with a dimension of approximately 1.20. ?? 1990.

  16. Surface characterization based upon significant topographic features

    Energy Technology Data Exchange (ETDEWEB)

    Blanc, J; Grime, D; Blateyron, F, E-mail: fblateyron@digitalsurf.fr [Digital Surf, 16 rue Lavoisier, F-25000 Besancon (France)

    2011-08-19

    Watershed segmentation and Wolf pruning, as defined in ISO 25178-2, allow the detection of significant features on surfaces and their characterization in terms of dimension, area, volume, curvature, shape or morphology. These new tools provide a robust way to specify functional surfaces.

  17. Spectroscopic study of cystine adsorption on pyrite surface: From vacuum to solution conditions

    Science.gov (United States)

    Sanchez-Arenillas, M.; Mateo-Marti, E.

    2015-09-01

    We characterized the adsorption of cystine molecules on pyrite surface via X-ray photoelectron spectroscopy. Anoxic conditions were simulated under ultra-high-vacuum conditions. In contrast, to simulate oxidation conditions, the molecules were adsorbed on pyrite surface from solution. A novel comparative analysis revealed remarkable differences with respect to molecular adsorption and surface chemistry induced by environmental conditions. Molecular adsorption under anoxic conditions was observed to be more favorable, concentrating a large number of molecules on the surface and two different chemical species. In contrast, the presence of oxygen induced an autocatalytic oxidation process on the pyrite surface, which facilitated water binding on pyrite surface and partially blocked molecular adsorption. Pyrite is a highly reactive surface and contains two crucial types of surface functional groups that drive molecular chemistry on the surface depending on the surrounding conditions. Therefore, the system explored in this study holds interesting implications for supporting catalyzed prebiotic chemistry reactions.

  18. Spatiotemporal Characterization of Extracellular Matrix Microstructures in Engineered Tissue: A Whole-Field Spectroscopic Imaging Approach.

    Science.gov (United States)

    Xu, Zhengbin; Ozcelikkale, Altug; Kim, Young L; Han, Bumsoo

    2013-02-01

    Quality and functionality of engineered tissues are closely related to the microstructures and integrity of their extracellular matrix (ECM). However, currently available methods for characterizing ECM structures are often labor-intensive, destructive, and limited to a small fraction of the total area. These methods are also inappropriate for assessing temporal variations in ECM structures. In this study, to overcome these limitations and challenges, we propose an elastic light scattering approach to spatiotemporally assess ECM microstructures in a relatively large area in a nondestructive manner. To demonstrate its feasibility, we analyze spectroscopic imaging data obtained from acellular collagen scaffolds and dermal equivalents as model ECM structures. For spatial characterization, acellular scaffolds are examined after a freeze/thaw process mimicking a cryopreservation procedure to quantify freezing-induced structural changes in the collagen matrix. We further analyze spatial and temporal changes in ECM structures during cell-driven compaction in dermal equivalents. The results show that spectral dependence of light elastically backscattered from engineered tissue is sensitively associated with alterations in ECM microstructures. In particular, a spectral decay rate over the wavelength can serve as an indicator for the pore size changes in ECM structures, which are at nanometer scale. A decrease in the spectral decay rate suggests enlarged pore sizes of ECM structures. The combination of this approach with a whole-field imaging platform further allows visualization of spatial heterogeneity of EMC microstructures in engineered tissues. This demonstrates the feasibility of the proposed method that nano- and micrometer scale alteration of the ECM structure can be detected and visualized at a whole-field level. Thus, we envision that this spectroscopic imaging approach could potentially serve as an effective characterization tool to nondestructively, accurately

  19. Spectroscopic detection, characterization and dynamics of free radicals relevant to combustion processes

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Terry [The Ohio State Univ., Columbus, OH (United States)

    2015-06-04

    Combustion chemistry is enormously complex. The chemical mechanisms involve a multitude of elementary reaction steps and a comparable number of reactive intermediates, many of which are free radicals. Computer simulations based upon these mechanisms are limited by the validity of the mechanisms and the parameters characterizing the properties of the intermediates and their reactivity. Spectroscopy can provide data for sensitive and selective diagnostics to follow their reactions. Spectroscopic analysis also provides detailed parameters characterizing the properties of these intermediates. These parameters serve as experimental gold standards to benchmark predictions of these properties from large-scale, electronic structure calculations. This work has demonstrated the unique capabilities of near-infrared cavity ringdown spectroscopy (NIR CRDS) to identify, characterize and monitor intermediates of key importance in complex chemical reactions. Our studies have focussed on the large family of organic peroxy radicals which are arguably themost important intermediates in combustion chemistry and many other reactions involving the oxidation of organic compounds. Our spectroscopic studies have shown that the NIR Ã - ˜X electronic spectra of the peroxy radicals allows one to differentiate among chemical species in the organic peroxy family and also determine their isomeric and conformic structure in many cases. We have clearly demonstrated this capability on saturated and unsaturated peroxy radicals and β-hydroxy peroxy radicals. In addition we have developed a unique dual wavelength CRDS apparatus specifically for the purpose of measuring absolute absorption cross section and following the reaction of chemical intermediates. The utility of the apparatus has been demonstrated by measuring the cross-section and self-reaction rate constant for ethyl peroxy.

  20. Caracterização química e espectroscópica de ácidos húmicos e fúlvicos isolados da camada superficial de latossolos brasileiros Chemical and spectroscopic characterization of humic and fulvic acids isolated from the surface layer of Brazilian oxisols

    Directory of Open Access Journals (Sweden)

    Leonardo Barros Dobbss

    2009-02-01

    Full Text Available A determinação de características estruturais das substâncias húmicas (SH é essencial para o entendimento do comportamento da química de superfície dos solos altamente intemperizados. Ácidos húmicos (AH e fúlvicos (AF obtidos no horizonte superficial de sete Latossolos de diferentes regiões do Brasil foram caracterizados mediante a análise da composição elementar, da acidez total e carboxílica, da capacidade de oxidação e por métodos espectroscópicos. As substâncias húmicas apresentaram elevado grau de oxidação, acidez e massa molecular relativamente baixas, caracterizando a matéria orgânica alcalina solúvel como bastante reativa. Os AF apresentaram menor teor de C e maior de O do que os AH. Foram observados valores elevados da relação entre absorvância em 465 e 665 nm (E4/E6 e a massa molar média foi estimada em 1.106 e 618 g mol-1 para AH e AF, respectivamente. A menor massa molar estimada para os AF foi compatível com sua menor complexidade química revelada pelos espectros de IV-TF, que apresentaram menor número de bandas de absorção bem definidas. A ressonância magnética nuclear (RMN ¹H mostrou a presença de H mais hidrofóbico nos AH e de H ligado a átomos de O em maior quantidade nos AF, compatível com sua maior acidez e, portanto, solubilidade em qualquer valor de pH. Apesar da mesma funcionalidade química encontrada tanto nos AH como nos AF, a análise estatística permitiu separar a maioria desses ácidos, indicando a presença de frações humificadas de natureza química individual.The determination of structural characteristics of humic substances (HS is essential to understand the behavior of surface chemistry of highly weathered soils. Humic acids (HA and fulvic acids (FA isolated from the surface horizon of seven Oxisols of different locations of Brazil were characterized by analyses of elemental composition, total and carboxylic acidity, oxidation capacity and spectroscopic techniques

  1. Integrated biomechanical and topographical surface characterization (IBTSC)

    Science.gov (United States)

    Löberg, Johanna; Mattisson, Ingela; Ahlberg, Elisabet

    2014-01-01

    In an attempt to reduce the need for animal studies in dental implant applications, a new model has been developed which combines well-known surface characterization methods with theoretical biomechanical calculations. The model has been named integrated biomechanical and topographical surface characterization (IBTSC), and gives a comprehensive description of the surface topography and the ability of the surface to induce retention strength with bone. IBTSC comprises determination of 3D-surface roughness parameters by using 3D-scanning electron microscopy (3D-SEM) and atomic force microscopy (AFM), and calculation of the ability of different surface topographies to induce retention strength in bone by using the local model. Inherent in this integrated approach is the use of a length scale analysis, which makes it possible to separate different size levels of surface features. The IBTSC concept is tested on surfaces with different level of hierarchy, induced by mechanical as well as chemical treatment. Sequential treatment with oxalic and hydrofluoric acid results in precipitated nano-sized features that increase the surface roughness and the surface slope on the sub-micro and nano levels. This surface shows the highest calculated shear strength using the local model. The validity, robustness and applicability of the IBTSC concept are demonstrated and discussed.

  2. Integrated biomechanical and topographical surface characterization (IBTSC)

    Energy Technology Data Exchange (ETDEWEB)

    Löberg, Johanna, E-mail: Johanna.Loberg@dentsply.com [Dentsply Implants, Box 14, SE-431 21 Mölndal (Sweden); Mattisson, Ingela [Dentsply Implants, Box 14, SE-431 21 Mölndal (Sweden); Ahlberg, Elisabet [Department of Chemistry and Molecular Biology, University of Gothenburg, SE-41296 Gothenburg (Sweden)

    2014-01-30

    In an attempt to reduce the need for animal studies in dental implant applications, a new model has been developed which combines well-known surface characterization methods with theoretical biomechanical calculations. The model has been named integrated biomechanical and topographical surface characterization (IBTSC), and gives a comprehensive description of the surface topography and the ability of the surface to induce retention strength with bone. IBTSC comprises determination of 3D-surface roughness parameters by using 3D-scanning electron microscopy (3D-SEM) and atomic force microscopy (AFM), and calculation of the ability of different surface topographies to induce retention strength in bone by using the local model. Inherent in this integrated approach is the use of a length scale analysis, which makes it possible to separate different size levels of surface features. The IBTSC concept is tested on surfaces with different level of hierarchy, induced by mechanical as well as chemical treatment. Sequential treatment with oxalic and hydrofluoric acid results in precipitated nano-sized features that increase the surface roughness and the surface slope on the sub-micro and nano levels. This surface shows the highest calculated shear strength using the local model. The validity, robustness and applicability of the IBTSC concept are demonstrated and discussed.

  3. Spectroscopic characterization of manganese-doped alkaline earth lead zinc phosphate glasses

    Indian Academy of Sciences (India)

    S Sreehari Sastry; B Rupa Venkateswara Rao

    2015-04-01

    Alkaline earth lead zinc phosphate glasses doped with Mn(II) are characterized by spectroscopic techniques like X-ray diffraction (XRD), UV–visible, differential scanning calorimetry (DSC), electron paramagnetic resonance (EPR), Fourier transform infrared (FTIR) and Raman. Optical absorption spectrum exhibits four bands which are characteristic of Mn(II) in distorted octahedral site symmetry. The crystal field parameter Dq and Racah interelectronic-repulsion parameters and have been evaluated. All investigated samples exhibit EPR signals which are characteristic to the Mn2+ ions. The shapes of spectra are also changed with varying alkaline earth ions content. FTIR spectra show specific vibrations of phosphate units. The characteristic Raman bands of these glasses due to stretching and bending vibrations were identified and analysed by varying alkaline earth content. The intensity and frequency variations for the characteristic phosphate group vibrations have been correlated with the changes of the structural units present in these glasses. Depolymerization of the phosphate chains in all the glasses is observed with replacement of alkaline earth content by spectroscopic studies. This leads to a strong decrease of the average chain length and a small decrease of the average P–O–P bridging angle with replacement of alkaline earth content.

  4. FT-IR spectroscopic, thermal analysis of human urinary stones and their characterization

    Science.gov (United States)

    Selvaraju, R.; Raja, A.; Thiruppathi, G.

    2015-02-01

    In the present study, FT-IR, XRD, TGA-DTA spectral methods have been used to investigate the chemical compositions of urinary calculi. Multi-components of urinary calculi such as calcium oxalate, hydroxyl apatite, struvite and uric acid have been studied. The chemical compounds are identified by FT-IR spectroscopic technique. The mineral identification was confirmed by powder X-ray diffraction patterns as compared with JCPDS reported values. Thermal analysis techniques are considered the best techniques for the characterization and detection of endothermic and exothermic behaviors of the urinary stones. The percentages of each hydrate (COM and COD) are present together, in the presences of MAPH or UA. Finally, the present study suggests that the Urolithiasis is significant health problem in children, and is very common in some parts of the world, especially in India. So that present study is so useful and helpful to the scientific community for identification of latest human health problems and their remedies using spectroscopic techniques.

  5. Surface characterization of carbohydrate microarrays.

    Science.gov (United States)

    Scurr, David J; Horlacher, Tim; Oberli, Matthias A; Werz, Daniel B; Kroeck, Lenz; Bufali, Simone; Seeberger, Peter H; Shard, Alexander G; Alexander, Morgan R

    2010-11-16

    Carbohydrate microarrays are essential tools to determine the biological function of glycans. Here, we analyze a glycan array by time-of-flight secondary ion mass spectrometry (ToF-SIMS) to gain a better understanding of the physicochemical properties of the individual spots and to improve carbohydrate microarray quality. The carbohydrate microarray is prepared by piezo printing of thiol-terminated sugars onto a maleimide functionalized glass slide. The hyperspectral ToF-SIMS imaging data are analyzed by multivariate curve resolution (MCR) to discern secondary ions from regions of the array containing saccharide, linker, salts from the printing buffer, and the background linker chemistry. Analysis of secondary ions from the linker common to all of the sugar molecules employed reveals a relatively uniform distribution of the sugars within the spots formed from solutions with saccharide concentration of 0.4 mM and less, whereas a doughnut shape is often formed at higher-concentration solutions. A detailed analysis of individual spots reveals that in the larger spots the phosphate buffered saline (PBS) salts are heterogeneously distributed, apparently resulting in saccharide concentrated at the rim of the spots. A model of spot formation from the evaporating sessile drop is proposed to explain these observations. Saccharide spot diameters increase with saccharide concentration due to a reduction in surface tension of the saccharide solution compared to PBS. The multivariate analytical partial least squares (PLS) technique identifies ions from the sugars that in the complex ToF-SIMS spectra correlate with the binding of galectin proteins.

  6. Evaluation of Mercaptobenzothiazole Anticorrosive Layer on Cu Surface by Spectroscopic Ellipsometry

    Science.gov (United States)

    Nishizawa, Hideaki; Sugiura, Osamu; Matsumura, Yoshiyuki; Kinoshita, Masaharu

    2007-05-01

    Mercaptobenzothiazole (MBT) anticorrosive layer on copper surface prepared in MBT solutions was analyzed by spectroscopic ellipsometry (SE). The results showed that MBT anticorrosive layer was formed on Cu2O layer in the MBT solution at temperatures higher than 50 °C. Additionally, it was confirmed that MBT anticorrosive layer was formed in the MBT solution at room temperature by adding about 20 wt % acetone to the solution. From polishing experiments of MBT anticorrosive layer and benzotriazole (BTA) layer, it was revealed that MBT anticorrosive layer was physically stronger than BTA layer. It is considered that dishing amount in Cu chemical-mechanical polishing (CMP) can be reduced by using MBT. However, MBT anticorrosive layer was not formed in the MBT solution including Hydrogen peroxide (H2O2) suggesting that slurry should be composed without H2O2 in order to use MBT for Cu CMP.

  7. Biodegradable starch-based films containing saturated fatty acids: thermal, infrared and raman spectroscopic characterization

    Directory of Open Access Journals (Sweden)

    Marcelo M. Nobrega

    Full Text Available Biodegradable films of thermoplastic starch and poly (butylene adipate co-terephthalate (PBAT containing fatty acids were characterized thermally and with infrared and Raman spectroscopies. The symmetrical character of the benzene ring in PBAT provided a means to illustrate the difference between these spectroscopic techniques, because a band appeared in the Raman spectrum but not in the infrared. The thermal analysis showed three degradation stages related to fatty acids, starch and PBAT. The incorporation of saturated fatty acids with different molecular mass (caproic, lauric and stearic did not change the nature of the chemical bonds among the components in the blends of starch, PBAT and glycerol, according to the thermal analysis, infrared and Raman spectroscopies.

  8. ATLAST detector needs for direct spectroscopic biosignature characterization in the visible and near-IR

    CERN Document Server

    Rauscher, Bernard J; Clampin, Mark; Domagal-Goldman, Shawn D; McElwain, Michael W; Moseley, S H; Stahle, Carl; Stark, Christopher C; Thronson, Harley A

    2015-01-01

    Are we alone? Answering this ageless question will be a major focus for astrophysics in coming decades. Our tools will include unprecedentedly large UV-Optical-IR space telescopes working with advanced coronagraphs and starshades. Yet, these facilities will not live up to their full potential without better detectors than we have today. To inform detector development, this paper provides an overview of visible and near-IR (VISIR; $\\lambda=0.4-1.8~\\mu\\textrm{m}$) detector needs for the Advanced Technology Large Aperture Space Telescope (ATLAST), specifically for spectroscopic characterization of atmospheric biosignature gasses. We also provide a brief status update on some promising detector technologies for meeting these needs in the context of a passively cooled ATLAST.

  9. Zinc acetylacetonate hydrate adducted with nitrogen donor ligands: Synthesis, spectroscopic characterization, and thermal analysis

    Science.gov (United States)

    Brahma, Sanjaya; Shivashankar, S. A.

    2015-12-01

    We report synthesis, spectroscopic characterization, and thermal analysis of zinc acetylacetonate complex adducted by nitrogen donor ligands, such as pyridine, bipyridine, and phenanthroline. The pyridine adducted complex crystallizes to monoclinic crystal structure, whereas other two adducted complexes have orthorhombic structure. Addition of nitrogen donor ligands enhances the thermal property of these complexes as that with parent metal-organic complex. Zinc acetylacetonate adducted with pyridine shows much higher volatility (106 °C), decomposition temperature (202 °C) as that with zinc acetylacetonate (136 °C, 220 °C), and other adducted complexes. All the adducted complexes are thermally stable, highly volatile and are considered to be suitable precursors for metal organic chemical vapor deposition. The formation of these complexes is confirmed by powder X-ray diffraction, Fourier transform infrared spectroscopy, mass spectroscopy, and elemental analysis. The complexes are widely used as starting precursor materials for the synthesis of ZnO nanostructures by microwave irradiation assisted coating process.

  10. Phenanthro[4,5-fgh]quinoxaline-Fused Subphthalocyanines: Synthesis, Structure, and Spectroscopic Characterization.

    Science.gov (United States)

    Pan, Houhe; Liu, Wenbo; Wang, Chiming; Wang, Kang; Jiang, Jianzhuang

    2016-07-01

    A series of four phenanthro[4,5-fgh]quinoxaline-fused subphthalocyanine derivatives 0-3 containing zero, one, two, and three phenanthro[4,5-fgh]quinoxaline moieties, respectively, were isolated from the mixed cyclotrimerization reaction of 2,9-di-tert-butylphenanthro[4,5-fgh]quinoxaline-5,6-dicarbonitrile with 4,5-bis(2,6-diisopropylphenoxy)phthalonitrile and characterized by a series of spectroscopic methods including MALDI-TOF mass, (1) H NMR, electronic absorption, magnetic circular dichroism (MCD), and fluorescence spectroscopy. The molecular structures for the compounds 0 and 2 were clearly revealed on the basis of single-crystal X-ray diffraction analysis. Their electrochemical properties were also studied by cyclic voltammetry. In particular, theoretical calculations in combination with the electronic absorption and electrochemical analyses revealed the significant influence of the fused-phenanthro[4,5-fgh]quinoxaline units on the electronic structures.

  11. Spectroscopic Characterization of N_{2}O_{5} Halide Clusters and the Formation of HNO_{3}

    Science.gov (United States)

    Denton, Joanna K.; Kelleher, Patrick J.; Menges, Fabian; Johnson, Mark

    2017-06-01

    N_{2}O_{5} is an atmospheric species which serves as night-time sink for NO_{x} species. Its reconversion to NO_{x} products occurs through solvation in atmospheric aerosols. Detection of N_{2}O_{5} and NO_{3}^{-} fragmentation products in such aerosols has previously utilized chemical ionization featuring halides (of which chlorine is ubiquitous in sea-spray aerosols). We examine the solvation behavior of N_{2}O_{5} and the critical number of water molecules to form HNO_{3} from N_{2}O_{5} and water. We have been able to generate and spectroscopically characterize N_{2}O_{5}-halide ions formed from halide-water clusters. We observe X^{-}N_{2}O_{5} species whose spectra best correspond to a calculated (O_{2}NX)(ONO_{2}^{-}) species. Funding for this work was provided by the NSF's Center for Aerosol Impacts on Climate and the Environment.

  12. Optical characterizations of complete TFT-LCD display devices by phase modulated spectroscopic ellipsometry

    Energy Technology Data Exchange (ETDEWEB)

    Gaillet, Melanie [HORIBA Jobin Yvon SAS, Thin Film Division, ZA de la Vigne aux Loups-5 avenue Arago, 91 380 Chilly-Mazarin (France); Yan Yi [HORIBA Jobin Yvon Inc., 3880 Park Ave., Edison, NJ 08820-3012 (United States)], E-mail: Li.Yan@jobinyvon.com; Teboul, Eric [HORIBA Jobin Yvon Inc., 3880 Park Ave., Edison, NJ 08820-3012 (United States)

    2007-12-03

    A commercially available phase modulated spectroscopic ellipsometer (PMSE) has been used to characterize a full thin film transistor-liquid crystal display (TFT-LCD) structure, including the glass substrates coated with transparent conducting indium tin oxide (ITO) layers, the twisted liquid crystal (LC) layer sandwiched in between, and the amorphous silicon (a-Si) TFT device which controls the luminance of a pixel. Due to its unique optical design, PMSE presents an unparallel capability to measure very accurately ultra thin films on transparent substrates as often found in display applications. Results show that the ITO layer is inhomogeneous in depth, corresponding to a graded microstructure. In addition, strong uniaxial anisotropy was determined for the liquid crystal device over the entire measured spectral range. Finally, doping effects on the optical properties of the a-Si layer of the TFT device were also measured.

  13. Spectroscopic microscopy can quantify the statistics of subdiffractional refractive-index fluctuations in media with random rough surfaces

    OpenAIRE

    Zhang, Di; Cherkezyan, Lusik; Capoglu, Ilker; Subramanian, Hariharan; Chandler, John; Thompson, Sebastian; Taflove, Allen; Backman, Vadim

    2015-01-01

    We previously established that spectroscopic microscopy can quantify subdiffraction-scale refractive index (RI) fluctuations in a label-free dielectric medium with a smooth surface. However, to study more realistic samples, such as biological cells, the effect of rough surface should be considered. In this Letter, we first report an analytical theory to synthesize microscopic images of a rough surface, validate this theory by finite-difference time-domain (FDTD) solutions of Maxwell’s equatio...

  14. Infrared Spectroscopic Evidence of Surface Speciation of Amino Acids on Titanium Dioxide

    Science.gov (United States)

    Jonsson, C. M.; Jonsson, C. L.; Parikh, S. J.; Sverjensky, D. A.; Cleaves, H. J.; Hazen, R. M.

    2008-12-01

    investigation of Glu and Asp interactions with the rutile surface using potentiometric titrations, adsorption experiments and FTIR spectroscopy. The spectroscopic evidence integrated with quantitative adsorption data and potentiometric titration data are used to describe the adsorption with surface complexation models. [1] Roddick-Lanzilotta A.D. and McQuillan A.J. (2000) J. Colloid & Interface Sci. 227, 48-54.

  15. Capturing latent fingerprints from metallic painted surfaces using UV-VIS spectroscope

    Science.gov (United States)

    Makrushin, Andrey; Scheidat, Tobias; Vielhauer, Claus

    2015-03-01

    In digital crime scene forensics, contactless non-destructive detection and acquisition of latent fingerprints by means of optical devices such as a high-resolution digital camera, confocal microscope, or chromatic white-light sensor is the initial step prior to destructive chemical development. The applicability of an optical sensor to digitalize latent fingerprints primarily depends on reflection properties of a substrate. Metallic painted surfaces, for instance, pose a problem for conventional sensors which make use of visible light. Since metallic paint is a semi-transparent layer on top of the surface, visible light penetrates it and is reflected off of the metallic flakes randomly disposed in the paint. Fingerprint residues do not impede light beams making ridges invisible. Latent fingerprints can be revealed, however, using ultraviolet light which does not penetrate the paint. We apply a UV-VIS spectroscope that is capable of capturing images within the range from 163 to 844 nm using 2048 discrete levels. We empirically show that latent fingerprints left behind on metallic painted surfaces become clearly visible within the range from 205 to 385 nm. Our proposed streakiness score feature determining the proportion of a ridge-valley pattern in an image is applied for automatic assessment of a fingerprint's visibility and distinguishing between fingerprint and empty regions. The experiments are carried out with 100 fingerprint and 100 non-fingerprint samples.

  16. Absorption mapping for characterization of glass surfaces.

    Science.gov (United States)

    Commandré, M; Roche, P; Borgogno, J P; Albrand, G

    1995-05-01

    The surface quality of bare substrates and preparation procedures take on an important role in optical coating performances. The most commonly used techniques of characterization generally give information about roughness and local defects. A photothermal deflection technique is used for mapping surface absorption of fused-silica and glass substrates. We show that absorption mapping gives specific information on surface contamination of bare substrates. We present experimental results concerning substrates prepared by different cleaning and polishing techniques. We show that highly polished surfaces lead to the lowest values of residual surface absorption. Moreover the cleaning behavior of surfaces of multicomponent glasses and their optical performance in terms of absorption are proved to be different from those of fused silica.

  17. In situ detection and characterization of potable water biofilms on materials by microscopic, spectroscopic and electrochemistry methods

    Energy Technology Data Exchange (ETDEWEB)

    Gamby, Jean [Universite Pierre et Marie Curie - Paris 6, CNRS-UPR 15, Laboratoire Interfaces et Systemes Electrochimiques, 4 Place Jussieu, Case Courrier 133, 75252 Paris Cedex 05 (France)], E-mail: jean.gamby@upmc.fr; Pailleret, Alain [Universite Pierre et Marie Curie - Paris 6, CNRS-UPR 15, Laboratoire Interfaces et Systemes Electrochimiques, 4 Place Jussieu, Case Courrier 133, 75252 Paris Cedex 05 (France); Clodic, Carol Boucher; Pradier, Claire-Marie [Universite Pierre et Marie Curie - Paris 6, CNRS-UMR 7609, Laboratoire de Reactivite de Surface, 4 Place Jussieu, Case Courrier 178, 75252 Paris Cedex 05 (France); Tribollet, Bernard [Universite Pierre et Marie Curie - Paris 6, CNRS-UPR 15, Laboratoire Interfaces et Systemes Electrochimiques, 4 Place Jussieu, Case Courrier 133, 75252 Paris Cedex 05 (France)

    2008-12-01

    We studied biofilm formation on stainless steel occurring in a drinking water distribution system which operated in parallel at 20 and 37 deg. C, in order to focus on the effect of temperature rather than on other operational and water quality parameters. A surface conditioning step was followed as a function of time on this material until adhesion of bacterial colonies by using microscopic methods: scanning electron microscopy (SEM) and atomic force microscopy (AFM); a spectroscopic method: polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS), and an electrochemical method: rotating disk electrode (RDE). Correlations between surface analysis, the duration of immersion of the sample and the influence of temperature have been identified clearly before bacterial adhesion. In cold water, these results showed an initial conditioning step of surface occurring during the first 8 days, with detection of superficial acidic functions grafted on surface, until adsorption of proteins. After 12 days, formation of independent bacteria microcolonies, reaching 2-3 {mu}m in length was observed. In tepid water, the first step was reduced to 2 days during which carbonates, acidic functions, and proteins were detected. After 90 days, the biofilm entered in a stable population state, which appeared as a bacteria rich film, including possibly Legionella. The spatial variation of the biofilm was limited as deduced from the thickness determination (about 4 {mu}m for 3-month period), using a RDE. The combination of these different techniques confirms successive steps for biofilm formation on stainless steel in a tap water. Then, we scrutinized the external near environment of bacteria including extracellular polymeric substances (EPS) and then further characterize the morphology of dominant bacteria (shape, size, flagellum) on gold substrate by AFM in air.

  18. Synthesis and Spectroscopic Characterization of New Ligand and Its Pd(II, Cu(II Metal Complexes

    Directory of Open Access Journals (Sweden)

    Isam Hussain Al-Karkhi

    2013-08-01

    Full Text Available A novel Schiff base ligand containing nitrogen and sulfur donor atoms was synthesized by condensing thioamide (TA with imidothioic acid (IT to form 1, 4 dithiane-2, 3-diamine (TAIT. Metal complexes of this ligand were prepared using Cu (II chloride dihydrates and Pd (III chloride. These complexes have been characterized using various physico-chemical and spectroscopic techniques. Based on physico-chemical and spectroscopic analyses, the structure of Cu (II complex is expected to be octahedral, while Pd (II complex is proposed to be square planner geometry. Schiff base and its metal complexes were expected to show strong bioactivity against microbes and cancer cells.

  19. Spectroscopic Characterization of Key Aromatic and Heterocyclic Molecules: A Route toward the Origin of Life

    Science.gov (United States)

    Puzzarini, Cristina; Baiardi, Alberto; Bloino, Julien; Barone, Vincenzo; Murphy, Thomas E.; Drew, H. Dennis; Ali, Ashraf

    2017-09-01

    To gain information on the abiotic synthesis of the building blocks of life from simple molecules, and their subsequent chemical evolution to biological systems, the starting point is the identification of target species in Titan-like planets; i.e., planets that resemble the primitive Earth, as well as in Earth-like planets in the habitable zone of their star, namely planets where life can be already originated. In this scenario, molecular spectroscopy plays a crucial role because spectroscopic signatures are at the basis of an unequivocal proof for the presence of these target molecules. Thanks to advances in many different techniques and NASA’s successful Kepler exoplanet transit mission, thousands of diverse planets outside of our solar system have been discovered. The James Webb Space Telescope (JWST), scheduled to be launched in 2018, will be very helpful in the identification of biosignature gases in Earth-like planets’ atmospheres and prebiotic molecule signatures in Titan-like atmospheres, by observing their absorption during transits. Although the search for key-target molecules in exoplanet atmospheres can be carried out by the JWST Transit Spectroscopy in the infrared (IR) region (0.6-29 μm wavelength range), opportunities for their detection in protostellar cores, protoplanetary disks, and on Titan are also offered by interferometric high spectral and spatial resolution observations using the Atacama Large Millimeter/submillimeter Array. In the present work, target molecules have been selected, and their spectroscopic characterization presented in view of supporting their infrared and complementary millimeter/submillimeter-wave spectral observations. In detail, the selected target molecules include: (1) the three-membered oxygen-containing heterocycles, oxirane and protonated oxirane; (2) the cyclopropenyl cation and its methyl derivative; (3) two examples of ortho- and peri-fused tri-cyclic aromatic rings, i.e., the phenalenyl cation ({{{C}}}13

  20. Surface science tools for nanomaterials characterization

    CERN Document Server

    2015-01-01

    Fourth volume of a 40volume series on nano science and nanotechnology, edited by the renowned scientist Challa S.S.R. Kumar. This handbook gives a comprehensive overview about Surface Science Tools for Nanomaterials Characterization. Modern applications and state-of-the-art techniques are covered and make this volume an essential reading for research scientists in academia and industry.

  1. Spectroscopic characterization of iron-doped II-VI compounds for laser applications

    Science.gov (United States)

    Martinez, Alan

    The middle Infrared (mid-IR) region of the electromagnetic spectrum between 2 and 15 ?m has many features which are of interest to a variety of fields such as molecular spectroscopy, biomedical applications, industrial process control, oil prospecting, free-space communication and defense-related applications. Because of this, there is a demand for broadly tunable, laser sources operating over this spectral region which can be easily and inexpensively produced. II-VI semiconductor materials doped with transition metals (TM) such as Co 2+, Cr2+, or Fe2+ exhibit highly favorable spectroscopic characteristics for mid-IR laser applications. Among these TM dopants, Fe2+ has absorption and emission which extend the farthest into the longer wavelength portion of the mid-IR. Fe2+:II-VI crystals have been utilized as gain elements in laser systems broadly tunable over the 3-5.5 microm range [1] and as saturable absorbers to Q -switch [2] and mode-lock [3] laser cavities operating over the 2.7-3 microm. TM:II-VI laser gain elements can be fabricated inexpensively by means of post-growth thermal diffusion with large homogeneous dopant concentration and good optical quality[4,5]. The work outlined in this dissertation will focus on the spectroscopic characterization of TM-doped II-VI semiconductors. This work can be categorized into three major thrusts: 1) the development of novel laser materials, 2) improving and extending applications of TM:II-VI crystals as saturable absorbers, and 3) fabrication of laser active bulk crystals. Because current laser sources based on TM:II-VI materials do not cover the entire mid-IR spectral region, it is necessary to explore novel laser sources to extend available emissions toward longer wavelengths. The first objective of this dissertation is the spectroscopic characterization of novel ternary host crystals doped with Fe2+ ions. Using crystal field engineering, laser materials can be prepared with emissions placed in spectral regions not

  2. Role of an Oxidant Mixture as Surface Modifier of Porous Silicon Microstructures Evaluated by Spectroscopic Ellipsometry.

    Science.gov (United States)

    Montiel-González, Zeuz; Escobar, Salvador; Nava, Rocío; del Río, J Antonio; Tagüeña-Martínez, Julia

    2016-04-21

    Current research on porous silicon includes the construction of complex structures with luminescent and/or photonic properties. However, their preparation with both characteristics is still challenging. Recently, our group reported a possible method to achieve that by adding an oxidant mixture to the electrolyte used to produce porous silicon. This mixture can chemically modify their microstructure by changing the thickness and surface passivation of the pore walls. In this work, we prepared a series of samples (with and without oxidant mixture) and we evaluated the structural differences through their scanning electron micrographs and their optical properties determined by spectroscopic ellipsometry. The results showed that ellipsometry is sensitive to slight variations in the porous silicon structure, caused by changes in their preparation. The fitting process, based on models constructed from the features observed in the micrographs, allowed us to see that the mayor effect of the oxidant mixture is on samples of high porosity, where the surface oxidation strongly contributes to the skeleton thinning during the electrochemical etching. This suggests the existence of a porosity threshold for the action of the oxidant mixture. These results could have a significant impact on the design of complex porous silicon structures for different optoelectronic applications.

  3. Vanadium oxide-carbon nanotube composite films characterized by spectroscopic ellipsometry

    Science.gov (United States)

    He, Qiong; Xu, Xiangdong; Gu, Yu; Wang, Meng; Yao, Jie; Jiang, Yadong; Sun, Minghui; Ao, Tianhong; Lian, Yuxiang; Wang, Fu; Li, Xinrong

    2016-10-01

    Spectroscopic ellipsometry (SE) is utilized to characterize the vanadium oxide (VO x )-single walled carbon nanotube (SWCNT) composite films prepared by sol-gel. Five Tauc-Lorentz oscillators model is employed to describe the dispersions in the optical responses of VO x and VO x -SWCNT thin films. Results reveal that if the SWCNT concentration in the composite film is increased, the refractive index is decreased, while the extinction coefficient is increased. Moreover, higher SWCNT content leads to lower optical band gap (E g) but larger localized state (E e). Interestingly, both E g and E e values reach saturated at a SWCNT content of ~8 wt%. Particularly, the peak transition energies of the 5 Tauc-Lorentz oscillators have been assigned to the specific transitions according to the band structures of VO x . This work reveals the feasibility of investigating the optical properties and microstructures of VO x -SWCNT composite films by SE. These experimental results will be helpful for better understanding the VO x -SWCNT composite films, and promoting future characterizations of other SWCNT-based composites by SE.

  4. Solvate Structures and Computational/Spectroscopic Characterization of LiPF6 Electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Han, Sang D.; Yun, Sung-Hyun; Borodin, Oleg; Seo, D. M.; Sommer, Roger D.; Young, Victor G.; Henderson, Wesley A.

    2015-04-23

    Raman spectroscopy is a powerful method for identifying ion-ion interactions, but only if the vibrational band signature for the anion coordination modes can be accurately deciphered. The present study characterizes the PF6- anion P-F Raman symmetric stretching vibrational band for evaluating the PF6-...Li+ cation interactions within LiPF6 crystalline solvates to create a characterization tool for liquid electrolytes. To facilitate this, the crystal structures for two new solvates—(G3)1:LiPF6 and (DEC)2:LiPF6 with triglyme and diethyl carbonate, respectively—are reported. The information obtained from this analysis provides key guidance about the ionic association information which may be obtained from a Raman spectroscopic evaluation of electrolytes containing the LiPF6 salt and aprotic solvents. Of particular note is the overlap of the Raman bands for both solvent-separated ion pair (SSIP) and contact ion pair (CIP) coordination in which the PF6- anions are uncoordinated or coordinated to a single Li+ cation, respectively.

  5. Adhesion to bovine dentin--surface characterization.

    Science.gov (United States)

    Ruse, N D; Smith, D C

    1991-06-01

    X-ray photo-electron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS) were used to characterize the dentin surface, to determine the effects of different pre-conditioning procedures on the elemental composition of the dentin surface, and to investigate the interaction between dentin and a dentin bonding agent (ScotchBond) by studying the changes in the elemental composition of dentin as a result of the interaction. Scanning electron microscopy (SEM) was used to characterize sample surface morphology, which was then correlated with surface elemental composition. The results showed that: (a) the elemental composition of the smear layer was similar to that of the underlying dentin; (b) cleaning with hydrogen-peroxide did not produce any modification in the elemental composition of the dentin surface; and (c) acid-etching led to an almost complete demineralization of the dentin, leaving behind an organic-rich surface. The results suggest that bonding systems that use acid-etching as a pre-conditioning procedure should be based on agents able to interact with the organic components of dentin, since bonding agents that rely on a chelation-to-calcium reaction are unlikely to be successful. The investigation of the interaction between the bonding agent and dentin led to a postulated adhesive-bonding reaction mechanism and suggested a partially cohesive failure in the bonding agent during fracturing of a dentin-bonding-agent-bonded assembly.

  6. Bright lights: disclosures from the optical, spectroscopic and chromatographic characterization of a 19th century Portuguese sedan chair

    Directory of Open Access Journals (Sweden)

    Catarina Miguel

    2016-01-01

    Full Text Available The Fundação Ricardo Espírito Santo Silva (FRESS as the mission of defend, train, study, develop and implement Portuguese Fine Arts in Portugal. This paper reflects the process of Conservation-Restoration training, where students apply the most recent analytical techniques to the characterization of artwork towards enabling and supporting conservation intervention. In this study, the materials used to produce a 19th century sedan chair were characterised by optical microscopy, spectroscopic (SEM-EDS, -Raman and FTIR-imaging and chromatographic (HPLC-DAD/MS techniques. The use of natural and synthetic dyes was identified in textiles found inside the chair, including cochineal, brazilwood and fuchsine. Several paint layers with different colours and compounds, such as barite, calcium carbonate, lead white, hematite and Prussian blue, were identified in the external painted wood surface of the chair. The variety of identified materials, interspersed between layers of animal glue, reflects the different interventions that took place on the chair over time, supporting the intervention strategies reported/prescribed for the conservation-restoration procedure.

  7. Attempted Isolation, Spectroscopic Characterization, and Computational Study of Diazirinone (N2CO), its Analogs, and their Precursors

    Science.gov (United States)

    Esselman, Brian J.; Nolan, Alex M.; Amberger, Brent K.; Shaffer, Chris J.; Woods, R. Claude; Stanton, John F.; McMahon, Robert J.

    2010-11-01

    Intrigued by the 2005 reported synthesis of diazirinone, we carried out further experimental and theoretical studies aimed at the detailed matrix-isolation and millimeter-wave spectroscopic characterizations. Diazirinone is a peculiar isoconjugate of two very stable molecules, CO and N2, which may be of astrochemical interest. Unfortunately, the previous reported methods of diazirinone generation did not yield this species, but rather its decomposition products. Encouraged by the many computational studies of the N2CO potential energy surface that all found diazirinone to be the lowest energy isomer, save its decomposition products, we proposed a new method of preparation of diazirinone from the photolysis or thermolysis of carbonyl diazide by loss of two nitrogen molecules. We were able to generate the highly explosive carbonyl diazide in sufficient yield from the reaction of triphosgene and sodium azide. This has allowed us to obtain a matrix-isolation and gas phase IR spectrum of carbonyl diazide which has a gas-phase lifetime of several days. We are currently engaged in the safe purification and distillation of our sample and obtaining a millimeter-wave spectrum of carbonyl diazide. We will attempt to photolyze or thermolyze this molecule to release diazirinone and characterize it by millimeter-wave spectroscopy to pave the way for possible astrochemical detection. In order to provide better mechanistic insight into the decomposition of carbonyl diazide to diazirinone, we have engaged in a DFT and ab initio computational study of several possible pathways. Our preliminary results suggest that of the pathways studied, a step-wise process in which an acyclic CON4 species is generated by loss of nitrogen followed by possible rearrangement and further loss of N2 is most likely. These results will be compared to the analogous reactions for azirinone (HC2NO), our next likely synthetic and spectroscopic target. The millimeter-wave absorption spectrometer used in this

  8. Planetary Surface Analysis Using Fast Laser Spectroscopic Techniques: Combined Microscopic Raman, LIBS, and Fluorescence Spectroscopy

    Science.gov (United States)

    Blacksberg, J.; Rossman, G. R.; Maruyama, Y.; Charbon, E.

    2011-12-01

    In situ exploration of planetary surfaces has to date required multiple techniques that, when used together, yield important information about their formation histories and evolution. We present a time-resolved laser spectroscopic technique that could potentially collect complementary sets of data providing information on mineral structure, composition, and hydration state. Using a picosecond-scale pulsed laser and a fast time-resolved detector we can simultaneously collect spectra from Raman, Laser Induced Breakdown Spectroscopy (LIBS), and fluorescence emissions that are separated in time due to the unique decay times of each process. The use of a laser with high rep rate (40 KHz) and low pulse energy (1 μJ/pulse) allows us to rapidly collect high signal to noise Raman spectra while minimizing sample damage. Increasing the pulse energy by about an order of magnitude creates a microscopic plasma near the surface and enables the collection of LIBS spectra at an unusually high rep rate and low pulse energy. Simultaneously, broader fluorescence peaks can be detected with lifetimes varying from nanosecond to microsecond. We will present Raman, LIBS, and fluorescence spectra obtained on natural mineral samples such as sulfates, clays, pyroxenes and carbonates that are of interest for Mars mineralogy. We demonstrate this technique using a photocathode-based streak camera detector as well as a newly-developed solid state Single Photon Avalanche Diode (SPAD) sensor array based on Complementary Metal-Oxide Semiconductor (CMOS) technology. We will discuss the impact of system design and detector choice on science return of a potential planetary surface mission, with a specific focus on size, weight, power, and complexity. The research described here was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (NASA).

  9. Characterization of a spectroscopic detector for application in x-ray computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Dooraghi, A. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Fix, B. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Smith, J. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Brown, W. D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Azevedo, S. G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Martz, H. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-04-21

    Recent advances in cadmium telluride (CdTe) energy-discriminating pixelated detectors have enabled the possibility of Multi-Spectral X-ray Computed Tomography (MSXCT) to incorporate spectroscopic information into CT. MultiX ME 100 V2 is a CdTe-based spectroscopic x-ray detector array capable of recording energies from 20 to 160 keV in 1.1 keV energy bin increments. Hardware and software have been designed to perform radiographic and computed tomography tasks with this spectroscopic detector. Energy calibration is examined using the end-point energy of a bremsstrahlung spectrum and radioisotope spectral lines. When measuring the spectrum from Am-241 across 500 detector elements, the standard deviation of the peak-location and FWHM measurements are ±0.4 and ±0.6 keV, respectively. As these values are within the energy bin size (1.1 keV), detector elements are consistent with each other. The count rate is characterized, using a nonparalyzable model with a dead time of 64 ± 5 ns. This is consistent with the manufacturer’s quoted per detector-element linear-deviation at 2 Mpps (million photons per sec) of 8.9% (typical) and 12% (max). When comparing measured and simulated spectra, a low-energy tail is visible in the measured data due to the spectral response of the detector. If no valid photon detections are expected in the low-energy tail, then a background subtraction may be applied to allow for a possible first-order correction. If photons are expected in the low-energy tail, a detailed model must be implemented. A radiograph of an aluminum step wedge with a maximum height of about 20 mm shows an underestimation of attenuation by about 10% at 60 keV. This error is due to partial energy deposition from higher-energy (> 60 keV) photons into a lower-energy (~60 keV) bin, reducing the apparent attenuation. A radiograph of a PTFE cylinder taken using a bremsstrahlung spectrum from an x-ray voltage of 100 kV filtered by 1.3 mm Cu is reconstructed using Abel inversion

  10. Spectroscopic Characterization of Poly(ortho-Aminophenol Film Electrodes: A Review Article

    Directory of Open Access Journals (Sweden)

    Ricardo Tucceri

    2013-01-01

    Full Text Available This paper refers to spectroscopic studies carried out to identify the products of o-aminophenol electro-oxidation and elucidate the structure of electrochemically synthesized poly(o-aminophenol (POAP films. Spectroscopic studies of the redox conversion of POAP are also reviewed.

  11. Corrosion investigation of fire-gilded bronze involving high surface resolution spectroscopic imaging

    Science.gov (United States)

    Masi, G.; Chiavari, C.; Avila, J.; Esvan, J.; Raffo, S.; Bignozzi, M. C.; Asensio, M. C.; Robbiola, L.; Martini, C.

    2016-03-01

    Gilded bronzes are often affected by severe corrosion, due to defects in the Au layer and Au/Cu alloy galvanic coupling, stimulated by large cathodic area of the gilded layer. Galvanic corrosion, triggered by gilding defects, leads to products growth at the Au/bronze interface, inducing blistering or break-up of the Au layer. In this context, fire-gilded bronze replicas prepared by ancient methods (use of spreadable Au-Hg paste) was specifically characterised by compiling complementary spectroscopic and imaging information before/after accelerated ageing with synthetic rain. Fire-gilded bronze samples were chemically imaged in cross-section at nano-metric scale (XPS). We have found a net surface enrichment in Zn and Sn after fire-gilding and presence of metallic Hg, Pb and Cu within the Au layer. Moreover, the composition distribution of the elements together with their oxidation has been determined. It was also revealed that metallic phases including Hg and Pb remain in the gilding after corrosion. Moreover, selective dissolution of Zn and Cu occurs in the crater due to galvanic coupling, which locally induces relative Sn species enrichment (decuprification). The feasibility advantages and disadvantages of chemical imaging using HR-SRPES to study artworks have been investigated on representative replicas.

  12. Computational characterization of ordered nanostructured surfaces

    Science.gov (United States)

    Mohieddin Abukhdeir, Nasser

    2016-08-01

    A vital and challenging task for materials researchers is to determine relationships between material characteristics and desired properties. While the measurement and assessment of material properties can be complex, quantitatively characterizing their structure is frequently a more challenging task. This issue is magnified for materials researchers in the areas of nanoscience and nanotechnology, where material structure is further complicated by phenomena such as self-assembly, collective behavior, and measurement uncertainty. Recent progress has been made in this area for both self-assembled and nanostructured surfaces due to increasing accessibility of imaging techniques at the nanoscale. In this context, recent advances in nanomaterial surface structure characterization are reviewed including the development of new theory and image processing methods.

  13. Spectroscopic Characterization of Intermolecular Interaction of Amyloid β Promoted on GM1 Micelles

    Directory of Open Access Journals (Sweden)

    Maho Yagi-Utsumi

    2011-01-01

    Full Text Available Clusters of GM1 gangliosides act as platforms for conformational transition of monomeric, unstructured amyloid β (Aβ to its toxic β-structured aggregates. We have previously shown that Aβ(1–40 accommodated on the hydrophobic/hydrophilic interface of lyso-GM1 or GM1 micelles assumes α-helical structures under ganglioside-excess conditions. For better understanding of the mechanisms underlying the α-to-β conformational transition of Aβ on GM1 clusters, we performed spectroscopic characterization of Aβ(1–40 titrated with GM1. It was revealed that the thioflavin T- (ThT- reactive β-structure is more populated in Aβ(1–40 under conditions where the Aβ(1–40 density on GM1 micelles is high. Under this circumstance, the C-terminal hydrophobic anchor Val39-Val40 shows two distinct conformational states that are reactive with ThT, while such Aβ species were not generated by smaller lyso-GM1 micelles. These findings suggest that GM1 clusters promote specific Aβ-Aβ interactions through their C-termini coupled with formation of the ThT-reactive β-structure depending on sizes and curvatures of the clusters.

  14. Spectroscopic characterization, antimicrobial activity, DFT computation and docking studies of sulfonamide Schiff bases

    Science.gov (United States)

    Mondal, Sudipa; Mandal, Santi M.; Mondal, Tapan Kumar; Sinha, Chittaranjan

    2017-01-01

    Schiff bases synthesised from the condensation of 2-(hydroxy)naphthaldehyde and sulfonamides (sufathiazole (STZ), sulfapyridine (SPY), sulfadiazine (SDZ), sulfamerazine (SMZ) and sulfaguanidine (SGN)) are characterized by different spectroscopic data (FTIR, UV-Vis, Mass, NMR) and two of them, (E)-4-(((2-hydroxynaphthalen-1-yl)methylene)amino)-N-(thiazol-2-yl)benzenesulfonamide (1a) and (E)-N-(diaminomethylene)-4-(((2-hydroxynaphthalen-1-yl)methylene)amino)benzenesulfonamide (1e) have been confirmed by single crystal X-ray structure determination. Antimicrobial activities of the Schiff bases have been evaluated against certified and resistant Gram positive (Staphylococcus aureus, Enterococcus facelis) and Gram negative (Streptococcus pyogenes, Salmonella typhi, Shigella dysenteriae, Shigella flexneri, Klebsiella pneumonia) pathogens. Performance of Schiff base against the resistant pathogens are better than standard stain and MIC data lie 32-128 μg/ml while parent sulfonamides are effectively inactive (MIC >512 μg/ml). The DFT optimized structures of the Schiff bases have been used to accomplish molecular docking studies with DHPS (dihydropteroate synthase) protein structure (downloaded from Protein Data Bank) to establish the most preferred mode of interaction. ADMET filtration, Cytotoxicity (MTT assay) and haemolysis assay have been examined for evaluation of druglike character.

  15. New quinolone derivative: Spectroscopic characterization and reactivity study by DFT and MD approaches

    Science.gov (United States)

    Ranjith, P. K.; Mary, Y. Sheena; Panicker, C. Yohannan; Anto, P. L.; Armaković, Stevan; Armaković, Sanja J.; Musiol, Robert; Jampilek, Josef; Van Alsenoy, C.

    2017-05-01

    The spectral characterization of ethyl-4-hydroxy-2-oxo-1, 2-dihydroquinoline-3-carboxylate (EHODQ3C) was performed by FT-IR and FT-Raman spectroscopic techniques and density functional theory computations have been carried using B3LYP/6-311++G(d,p) method. On the basis of potential energy distribution the vibrational assignments of the wavenumbers were proposed. Splitting of the Nsbnd H stretching mode and downshifted from the computed value which indicates the weakening of the Nsbnd H bond. NBO analysis was performed to study donor acceptor interactions. DFT calculations and molecular dynamics (MD) simulations have been combined in order to investigate fundamental reactive properties of the title molecule. To determine important reactive molecule sites we have calculated average local ionization energies (ALIE) and Fukui functions. Sensitivity towards autoxidation mechanism has been investigated by calculation of bond dissociation energies, while stability of title molecule in water has been investigated by calculation of radial distribution functions (RDF) after (MD) simulations. EHODQ3C exhibits inhibitory activity against ACP reductase and appears to be highly selective.

  16. Mercury And The Moon: Mid-infrared Spectroscopic Measurements Of The Surface

    Science.gov (United States)

    Donaldson Hanna, Kerri L.; Sprague, A. L.; Kozlowski, R. W.; Boccafolo, K.; Helbert, J.; Maturilli, A.; Warell, J.

    2006-09-01

    Spectroscopic observations (7.5 - 13 μm) of Mercury and the Moon obtained with MIRSI (Mid-Infrared Spectrometer and Imager) at the NASA Infrared Telescope Facility (IRTF) are presented. The spectra were acquired at mercurian W. longitudes 172 - 282° covering north polar to south polar latitudes. Also acquired were lunar surface measurements of the Apollo 16 landing site and Grimaldi basin and highlands. Mercury measurements covered Caloris Basin, Basin S, and other regions on the side not imaged by Mariner 10. Lunar locations were chosen for their known surface compositions determined from near-infrared spectral telescopic observations and Apollo return samples. Spectra for both bodies were reduced with the same calibration star to minimize reduction differences. Spectral differences between the mercurian locations indicate a heterogeneous composition and differences between Mercury and lunar spectra indicate compositional differences between the two bodies. All collected spectra from Mercury and the Moon show distinct and recognizable features including the Christiansen emissivity maximum and one or more transmission minima. Other features have yet to be identified. True emission spectra of rock and mineral powders with varying grain sizes will be presented for comparison with the data. Acknowledgements: The authors of this paper were Visiting Astronomers at the Infrared Telescope Facility, which is operated by the University of Hawaii under Cooperative Agreement no. NCC 5-538 with the National Aeronautics and Space Administration, Science Mission Directorate, Planetary Astronomy Program. We are especially grateful to Alan Tokunaga and Eric Tollestrup for useful engineering time on the telescope and Don Hunten for helpful discussions. This work was supported by NSF grant AST-0406796.

  17. A Multiscale Vibrational Spectroscopic Approach for Identification and Biochemical Characterization of Pollen.

    Directory of Open Access Journals (Sweden)

    Murat Bağcıoğlu

    Full Text Available Analysis of pollen grains reveals valuable information on biology, ecology, forensics, climate change, insect migration, food sources and aeroallergens. Vibrational (infrared and Raman spectroscopies offer chemical characterization of pollen via identifiable spectral features without any sample pretreatment. We have compared the level of chemical information that can be obtained by different multiscale vibrational spectroscopic techniques.Pollen from 15 different species of Pinales (conifers were measured by seven infrared and Raman methodologies. In order to obtain infrared spectra, both reflectance and transmission measurements were performed on ground and intact pollen grains (bulk measurements, in addition, infrared spectra were obtained by microspectroscopy of multigrain and single pollen grain measurements. For Raman microspectroscopy measurements, spectra were obtained from the same pollen grains by focusing two different substructures of pollen grain. The spectral data from the seven methodologies were integrated into one data model by the Consensus Principal Component Analysis, in order to obtain the relations between the molecular signatures traced by different techniques.The vibrational spectroscopy enabled biochemical characterization of pollen and detection of phylogenetic variation. The spectral differences were clearly connected to specific chemical constituents, such as lipids, carbohydrates, carotenoids and sporopollenins. The extensive differences between pollen of Cedrus and the rest of Pinaceae family were unambiguously connected with molecular composition of sporopollenins in pollen grain wall, while pollen of Picea has apparently higher concentration of carotenoids than the rest of the family. It is shown that vibrational methodologies have great potential for systematic collection of data on ecosystems and that the obtained phylogenetic variation can be well explained by the biochemical composition of pollen. Out of the

  18. Characterization of surface hydrophobicity of engineered nanoparticles.

    Science.gov (United States)

    Xiao, Yao; Wiesner, Mark R

    2012-05-15

    The surface chemistry of nanoparticles, including their hydrophobicity, is a key determinant of their fate, transport and toxicity. Engineered NPs often have surface coatings that control the surface chemistry of NPs and may dominate the effects of the nanoparticle core. Suitable characterization methods for surface hydrophobicity at the nano-scale are needed. Three types of methods, surface adsorption, affinity coefficient and contact angle, were investigated in this study with seven carbon and metal based NPs with and without coatings. The adsorption of hydrophobic molecules, Rose Bengal dye and naphthalene, on NPs was used as one measure of hydrophobicity and was compared with the relative affinity of NPs for octanol or water phases, analogous to the determination of octanol-water partition coefficients for organic molecules. The sessile drop method was adapted for measuring contact angle of a thin film of NPs. Results for these three methods were qualitatively in agreement. Aqueous-nC(60) and tetrahydrofuran-nC(60) were observed to be more hydrophobic than nano-Ag coated with polyvinylpyrrolidone or gum arabic, followed by nano-Ag or nano-Au with citrate-functionalized surfaces. Fullerol was shown to be the least hydrophobic of seven NPs tested. The advantages and limitations of each method were also discussed.

  19. Spectroscopic, morphological and electrochromic characterization of layer-by-layer hybrid films of polyaniline and hexaniobate nanoscrolls

    OpenAIRE

    Silva, Claudio H. B.; Galiote, Nelson A.; Huguenin,Fritz; Teixeira-Neto, Erico; Constantino, Vera R. L.; Marcia L. A. Temperini

    2012-01-01

    The combination of semiconducting oxides and polyaniline in the nanoscale range may result in hybrid materials having enhanced properties, such as electrochromism and charge capacity. This paper reports the spectroscopic, morphological and electrochromic characterization of hybrid films made up of hexaniobate one-dimensional (1D) nanoscrolls and polyaniline prepared by the layer-by-layer assembly technique (LbL). Secondary electron imaging and backscattered electron imaging techniques perform...

  20. Characterization of electrochemically modified polycrystalline platinum surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Krebs, L.C.; Ishida, Takanobu.

    1991-12-01

    The characterization of electrochemically modified polycrystalline platinum surfaces has been accomplished through the use of four major electrochemical techniques. These were chronoamperometry, chronopotentiommetry, cyclic voltammetry, and linear sweep voltammetry. A systematic study on the under-potential deposition of several transition metals has been performed. The most interesting of these were: Ag, Cu, Cd, and Pb. It was determined, by subjecting the platinum electrode surface to a single potential scan between {minus}0.24 and +1.25 V{sub SCE} while stirring the solution, that the electrocatalytic activity would be regenerated. As a consequence of this study, a much simpler method for producing ultra high purity water from acidic permanganate has been developed. This method results in water that surpasses the water produced by pyrocatalytic distillation. It has also been seen that the wettability of polycrystalline platinum surfaces is greatly dependent on the quantity of oxide present. Oxide-free platinum is hydrophobic and gives a contact angle in the range of 55 to 62 degrees. We have also modified polycrystalline platinum surface with the electrically conducting polymer poly-{rho}-phenylene. This polymer is very stable in dilute sulfuric acid solutions, even under applied oxidative potentials. It is also highly resistant to electrochemical hydrogenation. The wettability of the polymer modified platinum surface is severely dependent on the choice of supporting electrolyte chosen for the electrochemical polymerization. Tetraethylammonium tetrafluoroborate produces a film that is as hydrophobic as Teflon, whereas tetraethylammonium perchlorate produces a film that is more hydrophilic than oxide-free platinum.

  1. Characterization and flip angle calibration of 13C surface coils for hyperpolarization studies

    DEFF Research Database (Denmark)

    Hansen, Rie Beck; Gutte, Henrik; Larsen, Majbrit M E

    The aim of the present work is to address the challenge of optimal The aim of the present work is to address the challenge of optimal flflip angle calibration of ip angle calibration of C surface coils in C surface coils in hyperpolarization studies. To this end, we characterize the spatial pro h......-to-noise ratio for hyperpolarized C magnetic resonance C magnetic resonance spectroscopic imaging.......The aim of the present work is to address the challenge of optimal The aim of the present work is to address the challenge of optimal flflip angle calibration of ip angle calibration of C surface coils in C surface coils in hyperpolarization studies. To this end, we characterize the spatial pro...

  2. Electron spectroscopic study of electronic and morphological modifications of the WSe{sub 2} surface induced by Rb adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Buck, Jens

    2010-07-20

    The rubidium-covered surface of the semiconducting transition metal dichalcogenide tungsten diselenide (WSe{sub 2}) is examined using photoelectron spectroscopy (PES) and photoemission electron microscopy (PEEM). Adsorbed Rb is known to induce a variety of effects in this system concerning electronic, structural, and mechanical properties. In this work, the surface potential created by charge transfer upon Rb deposition is examined in thermal equilibrium (band bending) and stationary non-equilibrium (surface photovoltage (SPV) effect), which is induced by the absorption of light. It is shown that combined measurements and numerical simulations of the SPV effect as a function of the photon flux can be exploited for the estimation of many material parameters of the system, especially of the unoccupied adsorbate state. Issues of extending a conventional photoelectron spectrometer setup by a secondary light source will be discussed in the context of simulations and calibration measurements. The customization of an existing theoretical model of the SPV effect for the WSe{sub 2}: Rb system is introduced, and a comprehensive validation of the obtained predictions is given in the context of experimental data. In addition, the self-organized formation of Rb domains at room temperature was examined by application of spatially resolved XPS spectroscopy using the PEEM setup at the end station of beamline UE49/PGMa at the BESSY II synchrotron facility. From the obtained results, the arrangement of Rb in surface lattices can be concluded. Furthermore, an X-Ray absorption study of self-organized nanostructure networks, aiming at the chemical characterization, is presented. Based on the interpretation of the examined structures as tension-induced cracks, a statistical approach to analyzing large-scale features was pursued. First accordance with the predictions made by a primitive, mechanical model of crack creation developed here gives gives some evidence for the validity of the

  3. Spectroscopic determination of ground and excited state vibrational potential energy surfaces

    Science.gov (United States)

    Laane, Jaan

    Far-infrared spectra, mid-infrared combination band spectra, Raman spectra, and dispersed fluorescence spectra of non-rigid molecules can be used to determine the energies of many of the quantum states of conformationally important vibrations such as out-of-plane ring modes, internal rotations, and molecular inversions in their ground electronic states. Similarly, the fluorescence excitation spectra of jet-cooled molecules, together with electronic absorption spectra, provide the information for determining the vibronic energy levels of electronic excited states. One- or two-dimensional potential energy functions, which govern the conformational changes along the vibrational coordinates, can be determined from these types of data for selected molecules. From these functions the molecular structures, the relative energies between different conformations, the barriers to molecular interconversions, and the forces responsible for the structures can be ascertained. This review describes the experimental and theoretical methodology for carrying out the potential energy determinations and presents a summary of work that has been carried out for both electronic ground and excited states. The results for the out-of-plane ring motions of four-, five-, and six-membered rings will be presented, and results for several molecules with unusual properties will be cited. Potential energy functions for the carbonyl wagging and ring modes for several cyclic ketones in their S1(n,pi*) states will also be discussed. Potential energy surfaces for the three internal rotations, including the one governing the photoisomerization process, will be examined for trans-stilbene in both its S0 and S1(pi,pi*) states. For the bicyclic molecules in the indan family, the two-dimensional potential energy surfaces for the highly interacting ring-puckering and ring-flapping motions in both the S0 and S1(pi,pi*) states have also been determined using all of the spectroscopic methods mentioned above

  4. Alkynyl functionalized iminopyridine copper(I) phosphine complexes: Synthesis, spectroscopic characterization and photophysical properties

    Energy Technology Data Exchange (ETDEWEB)

    Jadhav, A.N.; Chavan, S.S., E-mail: sanjaycha2@rediffmail.com

    2014-04-15

    Some copper(I) complexes of type [Cu(L{sub 1})(PPh{sub 3}){sub 2}/(dppe)]X (1a–6a) and [Cu(L{sub 2})(PPh{sub 3}){sub 2}/(dppe)]X (1b–6b) [where L{sub 1}=N-(2-pyridylmethylene)-4-(trimethylsilylethynyl)aniline, L{sub 2}=N-(2-pyridylmethylene)-4-(phenylethynyl)aniline, PPh{sub 3}=triphenylphosphine, dppe=1,2-bis(diphenylphosphino)ethane, and X=ClO{sub 4}{sup −}, BF{sub 4}{sup −} and PF{sub 6}{sup −}] have been prepared and characterized on the basis of their elemental analyses and spectroscopic studies (IR, UV–visible, {sup 1}H NMR and {sup 31}P NMR). The representative complex of the series [Cu(L{sub 2})(PPh{sub 3}){sub 2}]ClO{sub 4}{sup −} (1b) has been characterized by single crystal X-ray diffraction which reveals that in the complex the central copper(I) ion assumes highly distorted-tetrahedral geometry. The UV–visible spectra indicate that the ancillary phosphine ligands significantly perturb the MLCT state of copper(I) complexes. Room temperature luminescence is observed for all copper(I) complexes in dichloromethane solution, indicating that alkynyl functionality on iminopyridine ligands enhances the emission property of copper(I) complexes and varies considerably with ancillary phosphine ligands. The thermal behavior of complexes revealed that copper(I) complexes with dppe ligand are thermally more stable than PPh{sub 3} complexes. All the complexes exhibit a quasireversible redox behavior corresponding to Cu(I)/Cu(II) couple and are sensitive to phosphine ligand. -- Highlights: • Synthesis of copper(I) complexes of alkynyl functionalized Schiff base. • Characterization by elemental analyses, IR, {sup 1}H NMR and {sup 31}P NMR spectral studies. • Electrochemical properties indicate a quasireversible redox behavior for all copper(I) complexes • All the copper(I) complexes exhibit intraligand (π→π{sup ⁎}) luminescence in dichloromethane.

  5. Characterization of water molecular state in in-vivo thick tissues using diffuse optical spectroscopic imaging

    Science.gov (United States)

    Chung, So Hyun

    Structural changes in water molecules are related to physiological, anatomical and pathological properties of tissues. Near infrared (NIR) optical absorption methods are sensitive to water; however, detailed characterization of water in thick tissues is difficult to achieve because subtle spectral shifts can be obscured by multiple light scattering. In the NIR, a water absorption peak is observed around 975 nm. The precise NIR peak's shape and position are highly sensitive to water molecular disposition. A bound water index (BWI) was developed that quantifies the spectral shift and shape changes observed in tissue water absorption spectra measured by broadband diffuse optical spectroscopic imaging (DOSI). DOSI quantitatively measures light absorption and scattering spectra in cm-deep tissues and therefore reveals bound water spectral shifts. BWI as a water state index was validated by comparing broadband DOSI to MRI and a conductivity cell using bound water phantoms. Non-invasive BWI measurements of malignant and normal tissues in 18 subjects showed a significantly higher fraction of free water in malignant tissues (pbreast cancer patients. The BWI and ADC correlated (R=0.8, p=<0.01) and both parameters decreased with increasing bulk water content in cancer tissues. Although BWI and ADC are positively correlated in vivo, BWI appears to be more sensitive to free water in the extracellular matrix while ADC reflects increased tumor cellularity. The relationship between ADC, BWI and bulk water concentration suggests that both parameters have potential for assessing tumor histopathological grade. My results confirm the importance of water as a critical tissue component that can potentially provide unique insight into the molecular pathophysiology of cancer.

  6. Spectroscopic Characterization of Dust-Fall Samples Collected from Greater Cairo, Egypt.

    Science.gov (United States)

    Shaltout, Abdallah A; Allam, Mousa A; Mostafa, Nasser Y; Heiba, Zein K

    2016-04-01

    This work aimed to characterize dust-fall samples collected from street's trees in Greater Cairo (GC), Egypt, and its surroundings by different spectroscopic techniques, namely; X-ray diffraction (XRD), attenuated total-reflection Fourier transform infrared (ATR-FTIR), particle-size analyzer, and scanning electron microscopy (SEM) combined with energy dispersive X-ray measurements. Samples were collected from 19 different locations inside and outside of GC. Quantitative phase analysis of the dust-fall samples was performed using the Rietveld method. Results showed that the most frequently observed phases in the dust-fall samples were calcite (CaCO3), dolomite (CaMg(CO3)2), gypsum (CaSO4·2H2O), and quartz (SiO2) with average concentrations of 39 ± 16, 8 ± 7, 22 ± 13, and 33 ± 14 wt%, respectively. The occurrence of these constituents referred to a combination of different anthropogenic and natural sources. The ATR-FTIR results are in good agreements with XRD data of the different observed phases. Based on the SEM and particle-size measurements, quantitative determination of the particle-size distribution was described. It was found that not only the large-sized particles are deposited but also the small-sized ones (PM10 and PM2.5). In addition, the particle size of the collected dust-fall samples varied from 0.1 to 200 µm with an average particle size of 17.36 µm; however, the particle size ranged from 2.5 to 40 µm predominated in all of the dust-fall samples.

  7. Spectroscopic characterization of novel multilayer mirrors intended for astronomical and laboratory applications

    Science.gov (United States)

    Ragozin, Eugene N.; Mednikov, Konstantin N.; Pertsov, Andrei A.; Pirozhkov, Alexander S.; Reva, Anton A.; Shestov, Sergei V.; Ul'yanov, Artem S.; Vishnyakov, Eugene A.

    2009-05-01

    We report measurements of the reflection spectra of (i) concave (spherical and parabolic) Mo/Si, Mg/Si, and Al/Zr multilayer mirrors (MMs) intended for imaging solar spectroscopy in the framework of the TESIS/CORONAS-FOTON Satellite Project and of (ii) an aperiodic Mo/Si MM optimized for maximum uniform reflectivity in the 125-250 Å range intended for laboratory applications. The reflection spectra were measured in the configuration of a transmission grating spectrometer employing the radiation of a tungsten laser-driven plasma as the source. The function of detectors was fulfilled by backside-illuminated CCDs coated with Al or Zr/Si multilayer absorption filters. High-intensity second-order interference reflection peaks at wavelengths of about 160 Å were revealed in the reflection spectra of the 304-Å Mo/Si MMs. By contrast, the second-order reflection peak in the spectra of the new-generation narrow-band (~12 Å FWHM) 304-Å Mg/Si MMs is substantially depressed. Manifestations of the NEXAFS structure of the L2, 3 absorption edges of Al and Al2O3 were observed in the spectra recorded. The broadband Mo/Si MM was employed as the focusing element of spectrometers in experiments involving (i) the charge exchange of multiply charged ions with the donor atoms of a rare-gas jet; (ii) the spectroscopic characterization of a debris-free soft X-ray radiation source excited by Nd laser pulses in a Xe jet (iii) near-IR-to-soft-X-ray frequency conversion (double Doppler effect) occurring in the retroreflection from the relativistic electron plasma wake wave (flying mirror) driven by a multiterawatt laser in a pulsed helium jet.

  8. Spectroscopic characterization of copper(I) binding to apo and metal-reconstituted zinc finger peptides.

    Science.gov (United States)

    Doku, Reginald T; Park, Grace; Wheeler, Korin E; Splan, Kathryn E

    2013-08-01

    Cu(I) exhibits high affinity for thiolate ligands, suggesting that thiol-rich zinc or iron binding sites may be subject to disruption during copper stress conditions. Zinc fingers constitute a large class of metalloproteins that use a combination of cysteine and histidine residues that bind Zn(II) as a structural element. Despite the shared preference of both copper and zinc for thiolate and amine coordination, the susceptibility of zinc finger domains toward copper substitution is not well studied. We report spectroscopic studies that characterize the Cu(I) binding properties of the zinc finger consensus peptides CP-CCHH, CP-CCHC, and CP-CCCC and the C-terminal zinc finger domain of HIV-1 nucleocapsid protein p7 (NCp7_C). Cu(I) binds to both the apopeptides and the Co(II)-substituted peptides, and the stoichiometry of Cu(I) binding is dependent on the number of cysteine thiols at the metal binding site. Fluorescence studies of the Zn(II)-NCp7_C complex indicate that Cu(I) also effectively competes with Zn(II) at the metal binding site, despite the high affinity of Zn(II) for the CCHC binding motif. Circular dichroism studies on both CP-CCHC and NCp7_C show that the conformations of the Cu(I)-bound complexes differ substantially from those of the Zn(II) species, implying that Cu(I) substitution is likely to impact zinc finger function. These results show that for the peptides studied here, Cu(I) is the thermodynamically favored metal despite the known high Zn(II) affinity of zinc finger domains, suggesting that Cu(I)-substituted zinc finger domains might be relevant in the context of both copper toxicity mechanisms and copper-responsive transcription factors.

  9. Absorption and fluorescence spectroscopic characterization of cryptochrome 3 from Arabidopsis thaliana.

    Science.gov (United States)

    Song, S-H; Dick, B; Penzkofer, A; Pokorny, R; Batschauer, A; Essen, L-O

    2006-10-02

    The blue light photoreceptor cryptochrome 3 (cry3) from Arabidopsis thaliana was characterized at room temperature in vitro in aqueous solution by optical absorption and emission spectroscopic studies. The protein non-covalently binds the chromophores flavin adenine dinucleotide (FAD) and N5,N10-methenyl-5,6,7,8-tetrahydrofolate (MTHF). In the dark-adapted state of cry3, the bound FAD is present in the oxidized form (FAD(ox), ca. 38.5%), in the semiquinone form (FADH., ca. 5%), and in the fully reduced neutral form (FAD(red)H2) or fully reduced anionic form (FAD(red)H-, ca. 55%). Some amount of FAD (ca. 1.5%) in the oxidized state remains unbound probably caused by chromophore release and/or denaturation. Förster-type energy transfer from MTHF to FAD(ox) is observed. Photo-excitation reversibly modifies the protein conformation causing a slight rise of the MTHF absorption strength and an increase of the MTHF fluorescence efficiency (efficient protein conformation photo-cycle). Additionally there occurs reversible reduction of bound FAD(ox) to FAD(red)H2 (or FAD(red)H-, FAD(ox) photo-cycle of moderate efficiency), reversible reduction of FADH. to FAD(red)H2 (or FAD(red)H-, FADH. photo-cycle of high efficiency), and modification of re-oxidable FAD(red)H2 (or FAD(red)H-) to permanent FAD(red)H2 (or FAD(red)H-) with low quantum efficiency. Photo-excitation of MTHF causes the reversible formation of a MTHF species (MTHF', MTHF photo-cycle, moderate quantum efficiency) with slow recovery to the initial dark state, and also the formation of an irreversible photoproduct (MTHF'').

  10. Surface Characterization of Virulent Treponema pallidum

    Science.gov (United States)

    Alderete, John F.; Baseman, Joel B.

    1980-01-01

    Characterization of the surface of Treponema pallidum was accomplished by [125I]lactoperoxidase-catalyzed iodination of intact organisms and sensitive radioimmunoprecipitation and gel electrophoresis technology. At least 11 outer membrane proteins with molecular weights ranging from 89,000 (89K) to 20K were identified, and all elicited high titers of antibody in experimentally infected rabbits. Proteins of 89.5K, 29.5K, and 25.5K previously implicated as ligands involved in attachment (J. B. Baseman and E. C. Hayes, J. Exp. Med. 151:573-586, 1980) were found to reside on the treponemal surface. Low levels of the 89.5K treponemal protein were released by high salt concentrations, whereas the remaining comigrating material was neither radioiodinated nor released with selective detergents. Other lower-molecular-weight (60K, 45K, and 30K) surface proteins were extracted with octyl glucoside detergent, suggesting their hydrophobic interaction with the external membrane. The molecular organization of surface proteins was studied by employing the cross-linker dithiobis(succinimidyl)-propionate, and data suggested the presence of a highly fluid envelope resulting in random collisions by the surface proteins. The biological function of the treponemal outer envelope proteins was evaluated using, as the indicator system, adherence of T. pallidum to monolayer cultures of eucaryotic cells. Trypsin treatment of motile, freshly harvested organisms decreased the extent of surface parasitism to normal rabbit testicular cells, reinforcing the idea of the proteinaceous nature and role of treponemal ligands for attachment. Other data supported functional and antigenic relatedness among the implicated ligands. Finally, brief periodate treatment of human epithelial (HEp-2) and normal rat testicular cells as well as casein-elicited rabbit peritoneal macrophages significantly reduced the extent of treponemal parasitism, suggesting a role of specific host membrane molecules as mediators of

  11. Structural insights, protein-ligand interactions and spectroscopic characterization of isoformononetin

    Science.gov (United States)

    Srivastava, Anubha; Singh, Harshita; Mishra, Rashmi; Dev, Kapil; Tandon, Poonam; Maurya, Rakesh

    2017-04-01

    Isoformononetin, a methoxylated isoflavone present in medicinal plants, has non-estrogenic bone forming effect via differential mitogen-activated protein kinase (MAPK) signaling. Spectroscopic (FT-Raman, FT-IR, UV-vis and NMR spectra) and quantum chemical calculations using density functional theory (DFT) and 6-311++G(d,p) as a large basis set have been employed to study the structural and electronic properties of isoformononetin. A detailed conformational analysis is performed to determine the stability among conformers and the various possibilities of intramolecular hydrogen bonding formation. Molecular docking studies with different protein kinases were performed on isoformononetin and previously studied isoflavonoid, formononetin in order to understand their inhibitory nature and the effect of functional groups on osteogenic or osteoporosis associated proteins. It is found that the oxygen atoms of methoxy, hydroxyl groups attached to phenyl rings R1, R3 and carbonyl group attached to pyran ring R2, play a major role in binding with the protein kinases that is responsible for the osteoporosis; however, no hydrophobic interactions are observed between rings of ligand and protein. The electronic properties such as HOMO and LUMO energies were determined by time-dependent TD-DFT which predict that conformer II is a little bit more stable and chemically low reactive than conformer I of isoformononetin. To estimate the structure-activity relationship, the molecular electrostatic potential (MEP) surface map, and reactivity descriptors are calculated from the optimized geometry of the molecule. From these results, it is also found that isoformononetin is kinetically more stable, less toxic, weak electrophile and chemically less reactive than formononetin. The atoms in molecules and natural bond orbital analysis are applied for the detailed analysis of intra and intermolecular hydrogen bonding interactions.

  12. Theoretical spectroscopic characterization at low temperatures of S-methyl thioformate and O-methyl thioformate

    Energy Technology Data Exchange (ETDEWEB)

    Senent, M. L., E-mail: senent@iem.cfmac.csic.es [Departamento de Química y Física Teóricas, Instituto de Estructura de la Materia, IEM-C.S.I.C., Serrano 121, Madrid 28006 (Spain); Puzzarini, C., E-mail: cristina.puzzarini@unibo.it [Dipartimento di Chimica G. Ciamician, Università di Bologna, Via F. Selmi 2, I-40126 Bologna (Italy); Hochlaf, M., E-mail: hochlaf@univ-mlv.fr [Laboratoire de Modélisation et Simulation Multi Echelle, Université Paris-Est, MSME UMR 8208 CNRS, 5 boulevard Descartes, 77454 Marne-la-Vallée (France); Domínguez-Gómez, R., E-mail: rosa.dominguez@upm.es [Departamento de Ingeniería Civil, Cátedra de Química, E.U.I.T. Obras Públicas, Universidad Politécnica de Madrid, Madrid (Spain); Carvajal, M., E-mail: miguel.carvajal@dfa.uhu.es [Departamento de Física Aplicada, Facultad de Ciencias Experimentales, Unidad Asociada IEM-CSIC-U.Huelva, Universidad de Huelva, 21071 Huelva (Spain)

    2014-09-14

    Highly correlated ab initio methods are employed to determine spectroscopic properties at low temperatures of two S-analogs of methyl formate: S-methyl thioformate CH{sub 3}-S-CHO (MSCHO) and O-methyl thioformate CH{sub 3}-O-CHS (MOCHS). Both species are detectable and they are expected to play an important role in Astrochemistry. Molecular properties are compared with those of the O-analog, methyl formate. Both isomers present two conformers cis and trans. cis-CH{sub 3}-S-CHO represents the most stable structure lying 4372.2 cm{sup −1} below cis-CH{sub 3}-O-CHS. The energy difference between the cis and trans forms is drastically lower for MSCHO (1134 cm{sup −1}) than for MOCHS (1963.6 cm{sup −1}). Harmonic and anharmonic fundamentals and the corresponding intensities, as well as the rotational constants for the ground vibrational and first excited torsional states and the centrifugal distortions constants, are provided. Low torsional energy levels have been obtained by solving variationally a two dimensional Hamiltonian expressed in terms of the two torsional degrees of freedom. The corresponding 2D potential energy surfaces have been computed at the CCSD(T)/aug-cc-pVTZ level of theory. The methyl torsional barriers V{sub 3}(cis) are determined to be 139.7 cm{sup −1} (CH{sub 3}-S-CHO) and 670.4 cm{sup −1} (CH{sub 3}-O-CHS). The A/E splitting of ground torsional state has been estimated to be 0.438 cm{sup −1} for CH{sub 3}-S-CHO and negligible for CH{sub 3}-O-CHS.

  13. Analysis of corrosion layers in ancient Roman silver coins with high resolution surface spectroscopic techniques

    Energy Technology Data Exchange (ETDEWEB)

    Keturakis, Christopher J. [Operando Molecular Spectroscopy and Catalysis Research Laboratory, Department of Chemical Engineering, Lehigh University, Bethlehem, PA 18015 (United States); Notis, Ben [Brandeis University, Waltham, MA 02453 (United States); Blenheim, Alex [Department of Mechanical Engineering, Pennsylvania State University, College Park, PA 16802 (United States); Miller, Alfred C.; Pafchek, Rob [Zettlemoyer Center for Surface Studies, Lehigh University, Bethlehem, PA 18015 (United States); Notis, Michael R., E-mail: mrn1@lehigh.edu [Department of Materials Science and Engineering, Lehigh University, Bethlehem, PA 18015 (United States); Wachs, Israel E., E-mail: iew0@lehigh.edu [Operando Molecular Spectroscopy and Catalysis Research Laboratory, Department of Chemical Engineering, Lehigh University, Bethlehem, PA 18015 (United States)

    2016-07-15

    Highlights: • Five ancient silver alloy coins (225 BCE–244 CE) were analyzed using surface characterization techniques. • Both destructive and non-destructive surface characterization methods were developed. • Alloying with copper, even in small amounts, leads to the formation of an outer Cu{sub 2}O corrosion layer. - Abstract: Determination of the microchemistry of surface corrosion layers on ancient silver alloy coins is important both in terms of understanding the nature of archaeological environmental conditions to which these ancient coins were exposed and also to help in their conservation. In this present study, five ancient silver alloy coins (225 BCE–244 CE) were used as test vehicles to measure their immediate surface microchemistry and evaluate the appropriateness and limitations of High Sensitivity-Low Energy Ion Scattering Spectroscopy (HS-LEIS, 0.3 nm depth analysis), High Resolution-X-ray Photoelectron Spectroscopy (HR-XPS, 1–3 nm depth analysis) and High Resolution-Raman Spectroscopy (HR-Raman, ∼1000 nm depth analysis). Additional information about the deeper corrosion layers, up to ∼300–1000 nm, was provided by dynamic HS-LEIS and HR-Raman spectroscopy. While not archeologically significant, the use of these coins of small commercial value provides data that is more representative of the weaker signals typically obtained from ancient corroded objects, which can be in stark contrast to pristine data often obtained from carefully prepared alloys of known composition. The oldest coins, from 225 to 214 BCE, possessed an outermost surface layer containing Cu{sub 2}O, Na, Al, Pb, and adsorbed hydrocarbons, while the more recent coins, from 98 to 244 CE, contained Cu{sub 2}O, Ag, N, F, Na, Al, S, Cl, and adsorbed hydrocarbons in similar corresponding surface layers. It thus appears that alloying with copper, even in small amounts, leads to the formation of an outer Cu{sub 2}O layer. Depth profiling revealed the presence of K, Na, Cl, and

  14. Corrosion investigation of fire-gilded bronze involving high surface resolution spectroscopic imaging

    Energy Technology Data Exchange (ETDEWEB)

    Masi, G., E-mail: giulia.masi5@unibo.it [Dipartimento di Ingegneria Civile, Chimica, Ambientale e dei Materiali, Università di Bologna, via Terracini 28, 40131 Bologna (Italy); Chiavari, C., E-mail: cristina.chiavari@unibo.it [Dipartimento di Ingegneria Civile, Chimica, Ambientale e dei Materiali, Università di Bologna, via Terracini 28, 40131 Bologna (Italy); C.I.R.I. (Centro Interdipartimentale Ricerca Industriale) Meccanica Avanzata e Materiali, Università di Bologna, Bologna, via Terracini 28, 40131 Bologna (Italy); Avila, J., E-mail: jose.avila@synchrotron-soleil.fr [Synchrotron SOLEIL, L’Orme des Merisiers, 91190 Saint-Aubin (France); Esvan, J., E-mail: jerome.esvan@ensiacet.fr [Centre Interuniversitaire de Recherche et d’Ingénierie des Matériaux, Université de Toulouse, 4 allée Emile Monso, 31030 Toulouse (France); Raffo, S., E-mail: simona.raffo2@unibo.it [Dipartimento di Chimica Industriale “Toso Montanari”, Università di Bologna, viale Risorgimento 4, 40136 Bologna (Italy); Bignozzi, M.C., E-mail: maria.bignozzi@unibo.it [Dipartimento di Ingegneria Civile, Chimica, Ambientale e dei Materiali, Università di Bologna, via Terracini 28, 40131 Bologna (Italy); Asensio, M.C., E-mail: maria-carmen.asensio@synchrotron-soleil.fr [Synchrotron SOLEIL, L’Orme des Merisiers, 91190 Saint-Aubin (France); Robbiola, L., E-mail: robbiola@univ-tlse2.fr [TRACES Lab (CNRS UMR5608), Université Toulouse Jean-Jaurès, 5, allées Antonio-Machado, 31058 Toulouse (France); and others

    2016-03-15

    Graphical abstract: - Highlights: • Fire-gilded bronze prepared by ancient methods (Au–Hg layer on Cu–Sn–Zn–Pb–Sb). • Heating during gilding induces Sn and Znenrichment in the top part of the gilded layer. • SR-HRPES mapping of corrosion craters (cross-section) after accelerated ageing. • Selective dissolution of Cu and Zn in the craters induces Sn species enrichment. • The main species in the craters are related to hydroxi-oxide compounds. - Abstract: Gilded bronzes are often affected by severe corrosion, due to defects in the Au layer and Au/Cu alloy galvanic coupling, stimulated by large cathodic area of the gilded layer. Galvanic corrosion, triggered by gilding defects, leads to products growth at the Au/bronze interface, inducing blistering or break-up of the Au layer. In this context, fire-gilded bronze replicas prepared by ancient methods (use of spreadable Au–Hg paste) was specifically characterised by compiling complementary spectroscopic and imaging information before/after accelerated ageing with synthetic rain. Fire-gilded bronze samples were chemically imaged in cross-section at nano-metric scale (<200 nm) using high energy and lateral resolution synchrotron radiation photoemission (HR-SRPES) of core levels and valence band after conventional characterisation of the samples by Glow Discharge optical Emission Spectroscopy (GD-OES) and conventional X-ray photoelectron spectroscopy (XPS). We have found a net surface enrichment in Zn and Sn after fire-gilding and presence of metallic Hg, Pb and Cu within the Au layer. Moreover, the composition distribution of the elements together with their oxidation has been determined. It was also revealed that metallic phases including Hg and Pb remain in the gilding after corrosion. Moreover, selective dissolution of Zn and Cu occurs in the crater due to galvanic coupling, which locally induces relative Sn species enrichment (decuprification). The feasibility advantages and disadvantages of

  15. A plateau-valley separation method for multifunctional surfaces characterization

    DEFF Research Database (Denmark)

    Godi, Alessandro; Kühle, A.; De Chiffre, Leonardo

    2012-01-01

    Turned multifunctional surfaces are a new typology of textured surfaces presenting a flat plateau region and deterministically distributed lubricant reservoirs. Existing standards are not suitable for the characterization of such surfaces, providing at times values without physical meaning. A new...

  16. Spectroscopic and functional characterization of iron-bound forms of Azotobacter vinelandii (Nif)IscA.

    Science.gov (United States)

    Mapolelo, Daphne T; Zhang, Bo; Naik, Sunil G; Huynh, Boi Hanh; Johnson, Michael K

    2012-10-16

    The ability of Azotobacter vinelandii(Nif)IscA to bind Fe has been investigated to assess the role of Fe-bound forms in NIF-specific Fe-S cluster biogenesis. (Nif)IscA is shown to bind one Fe(III) or one Fe(II) per homodimer and the spectroscopic and redox properties of both the Fe(III)- and Fe(II)-bound forms have been characterized using the UV-visible absorption, circular dichroism, and variable-temperature magnetic circular dichroism, electron paramagnetic resonance, Mössbauer and resonance Raman spectroscopies. The results reveal a rhombic intermediate-spin (S = 3/2) Fe(III) center (E/D = 0.33, D = 3.5 ± 1.5 cm(-1)) that is most likely 5-coordinate with two or three cysteinate ligands and a rhombic high spin (S = 2) Fe(II) center (E/D = 0.28, D = 7.6 cm(-1)) with properties similar to reduced rubredoxins or rubredoxin variants with three cysteinate and one or two oxygenic ligands. Iron-bound (Nif)IscA undergoes reversible redox cycling between the Fe(III)/Fe(II) forms with a midpoint potential of +36 ± 15 mV at pH 7.8 (versus NHE). l-Cysteine is effective in mediating release of free Fe(II) from both the Fe(II)- and Fe(III)-bound forms of (Nif)IscA. Fe(III)-bound (Nif)IscA was also shown to be a competent iron source for in vitro NifS-mediated [2Fe-2S] cluster assembly on the N-terminal domain of NifU, but the reaction occurs via cysteine-mediated release of free Fe(II) rather than direct iron transfer. The proposed roles of A-type proteins in storing Fe under aerobic growth conditions and serving as iron donors for cluster assembly on U-type scaffold proteins or maturation of biological [4Fe-4S] centers are discussed in light of these results.

  17. Crystal structure, complexation, spectroscopic characterization and antimicrobial evaluation of 3,4-dihydroxybenzylidene isonicotinyl-hydrazone

    Science.gov (United States)

    Jeragh, Bakir; Ali, Mayada S.; El-Asmy, Ahmed A.

    2015-06-01

    A single crystal of 3,4-dihydroxybenzylidene isonicotinylhydrazone, HBINH, has been grown and solved by X-ray crystallography. The VO2+, Zr4+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Hg2+ and Pd2+ complexes of HBINH have been prepared and spectroscopically characterized. The data confirmed the formulae [Co(HBINH)(H2O)Cl]Cl·H2O, [Pd(HBINH)Cl2], [Zn(HBINH)2Cl2], [Cd(HBINH)(H2O)2Cl2]·1½H2O, [(VO)2(HBINH-3H)(OH)(H2O)], [Ni2(HBINH)(H2O)6Cl2]Cl2, [Cu2(HBINH-3H)(H2O)2(OAc)]·3H2O, [Zr2(HBINH-3H)Cl4]Cl, [Hg2(HBINH)Cl4] and the dimer {[Cu(HBINH)Cl]Cl}2. Most of the complexes have intense colors and high melting points and some are electrolytes in DMSO solution. The ligand behaves as a neutral bidentate in the Co(II), Cu(II), Pd(II), Zn(II) and Cd(II) complexes; dibasic tetradentate in [Ni2(HBINH)(H2O)6Cl2]Cl2 and tribasic tetradentate in [Cu2(HBINH-3H)(OAc)]·5H2O, [(VO)2(HBINH-3H)(OH)(H2O)] and [Zr2(HBINH-3H)Cl4]Cl by the loss of 3H+ due to the deprotonation of the two hydroxyl groups and the enolization of the amide (Odbnd CNH) group. A tetrahedral geometry was proposed for the Co(II), Cu(II), Zn(II) and Hg(II) complexes; square-planar for the Pd(II) complex; square-pyramid for the VO2+ complex and octahedral for the Ni(II) and Cd(II) complexes. The complexes [Cd(HBINH)(H2O)2Cl2]·1½H2O, [(VO)2(HBINH-3H)(OH)(H2O)] and [Cu2(HBINH-3H)-(H2O)2(OAc)]·3H2O have activities against Bacillus sp. M3010, Candida albicans, Escherichia coli, Staphylococcus aureus and Slamonella sp. PA393.

  18. Growth and spectroscopic characterization of monolayer and few-layer hexagonal boron nitride on metal substrates

    Science.gov (United States)

    Feigelson, Boris N.; Bermudez, Victor M.; Hite, Jennifer K.; Robinson, Zachary R.; Wheeler, Virginia D.; Sridhara, Karthik; Hernández, Sandra C.

    2015-02-01

    Atomically thin two dimensional hexagonal boron nitride (2D h-BN) is one of the key materials in the development of new van der Waals heterostructures due to its outstanding properties including an atomically smooth surface, high thermal conductivity, high mechanical strength, chemical inertness and high electrical resistance. The development of 2D h-BN growth is still in the early stages and largely depends on rapid and accurate characterization of the grown monolayer or few layers h-BN films. This paper demonstrates a new approach to characterizing monolayer h-BN films directly on metal substrates by grazing-incidence infrared reflection absorption spectroscopy (IRRAS). Using h-BN films grown by atmospheric-pressure chemical vapor deposition on Cu and Ni substrates, two new sub-bands are found for the A2u out-of-plane stretching mode. It is shown, using both experimental and computational methods, that the lower-energy sub-band is related to 2D h-BN coupled with substrate, while the higher energy sub-band is related to decoupled (or free-standing) 2D h-BN. It is further shown that this newly-observed fine structure in the A2u mode can be used to assess, quickly and easily, the homogeneity of the h-BN-metal interface and the effects of metal surface contamination on adhesion of the layer.

  19. Chemical and spectroscopic characterization of a vegetable oil used as dielectric coolant in distribution transformers

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, Neffer A.; Abonia, Rodrigo, E-mail: rodrigo.abonia@correounivalle.edu.co [Departamento de Quimica, Escuela de Ingenieria Electrica, Universidad del Valle, Cali (Colombia); Cadavid, Hector [Grupo GRALTA, Escuela de Ingenieria Electrica, Universidad del Valle, Cali (Colombia); Vargas, Ines H. [Area de Ingenieria de Distribucion, Empresas Publicas de Medellin (EPM), Medellin (Colombia)

    2011-09-15

    In this work, a complete UV-Vis, IR and (1H, 13C and DEPT) NMR spectroscopic analysis was performed for a FR3 vegetable oil sample used as dielectric coolant in an experimental distribution transformer. The same spectroscopic analysis was performed for three used FR3 oil samples (i.e., 4 months in use, 8 months in use and 7 years in use), removed from several operating distribution transformers. Comparison of the data indicated that no significant spectroscopic changes, and hence, no structural changes occurred to the oils by the use. Chemical transformations like catalytic hydrogenation (hardening) and hydrolysis were performed to the FR3 oil sample and the obtained products were analyzed by spectroscopic methods in order to collect further structural information about the FR3 oil. Accelerated aging tests in laboratory were also performed for three FR3 oil samples affording interesting information about the structure of the degradation products. These findings would be valuable to search for a spectroscopy-based technique for monitoring the lifetime and performance of this insulating vegetable oil. (author)

  20. Characterization of plasmonic effects in thin films and metamaterials using spectroscopic ellipsometry

    NARCIS (Netherlands)

    Oates, T.W.H.; Wormeester, H.; Arwin, H.

    2011-01-01

    In this article, spectroscopic ellipsometry studies of plasmon resonances at metal–dielectric interfaces of thin films are reviewed. We show how ellipsometry provides valuable non-invasive amplitude and phase information from which one can determine the effective dielectric functions, and how these

  1. Spectroscopic characterization of Co3O4 catalyst doped with CeO2 and PdO for methane catalytic combustion.

    Science.gov (United States)

    Jodłowski, P J; Jędrzejczyk, R J; Rogulska, A; Wach, A; Kuśtrowski, P; Sitarz, M; Łojewski, T; Kołodziej, A; Łojewska, J

    2014-10-15

    The study deals with the XPS, Raman and EDX characterization of a series of structured catalysts composed of cobalt oxides promoted by palladium and cerium oxides. The aim of the work was to relate the information gathered from spectroscopic analyses with the ones from kinetic tests of methane combustion to establish the basic structure-activity relationships for the catalysts studied. The most active catalyst was the cobalt oxide doped with little amount of palladium and wins a confrontation with pure palladium oxide catalyst which is commercially used in converters for methane. The analyses Raman and XPS analyses showed that this catalyst is composed of a cobalt spinel and palladium oxide. The quantitative approach to the composition of the catalysts by XPS and EDX methods revealed that the surface of palladium doped cobalt catalyst is enriched with palladium oxide which provides a great number of active centres for methane combustion indicated by kinetic parameters.

  2. Thermal characterization of nanoporous 'black silicon' surfaces

    Science.gov (United States)

    Nichols, Logan; Duan, Wenqi; Toor, Fatima

    2016-09-01

    In this work we characterize the thermal conductivity properties of nanoprous `black silicon' (bSi). We fabricate the nanoporous bSi using the metal assisted chemical etching (MACE) process utilizing silver (Ag) metal as the etch catalyst. The MACE process steps include (i) electroless deposition of Ag nanoparticles on the Si surface using silver nitrate (AgNO3) and hydrofluoric acid (HF), and (ii) a wet etch in a solution of HF and hydrogen peroxide (H2O2). The resulting porosity of bSi is dependent on the ratio of the concentration of HF to (HF + H2O2); the ratio is denoted as rho (ρ). We find that as etch time of bSi increases the thermal conductivity of Si increases as well. We also analyze the absorption of the bSi samples by measuring the transmission and reflection using IR spectroscopy. This study enables improved understanding of nanoporous bSi surfaces and how they affect the solar cell performance due to the porous structures' thermal properties.

  3. Laser Spectroscopic Study on Oxygen Isotope Effects in Ozone Surface Decomposition

    Science.gov (United States)

    Minissale, Marco; Boursier, Corinne; Elandaloussi, Hadj; Te, Yao; Jeseck, Pascal; Rouille, Christian; Zanon-Willette, Thomas; Janssen, Christof

    2016-04-01

    The isotope kinetics of ozone formation in the Chapman reaction [1] O + O2 + M → O3 + M (1) provides the primary example for a chemically induced oxygen isotope anomaly and is associated with large [2] and mass independent [3] oxygen isotope enrichments in the product molecule, linked to a symmetry selection in the ozone formation kinetics [4-5]. The isotopic composition of ozone and its transfer to other molecules is a powerful tracer in the atmospheric and biogeochemical sciences [6] and serves as a primary model for a possible explanation of the oxygen isotopic heterogeneity in the Solar system [7-8]. Recently, the isotope fractionation in the photolytic decomposition process O3 + hν → O2 + O (2) using visible light has been studied in detail [9-10]. Much less is currently known about the isotope fractionation in the dry deposition or in the gas phase thermal decomposition of ozone O3 + M → O2 + O +M. (3) Here we report on first spectroscopic studies of non-photolytic ozone decomposition using a cw-quantum cascade laser at 9.5 μm. The concentration of individual ozone isotopomers (16O3,16O16O17O, and 16O17O16O) in a teflon coated reaction cell is followed in real time at temperatures between 25 and 150 °C. Observed ozone decay rates depend on homogeneous (reaction (3)) processes in the gas phase and on heterogeneous reactions on the wall. A preliminary analysis reveals agreement with currently recommended ozone decay rates in the gas phase and the absence of a large symmetry selection in the surface decomposition process, indicating the absence of a mass independent fractionation effect. This result is in agreement with previous mass spectrometer (MS) studies on heterogeneous ozone formation on pyrex [11], but contradicts an earlier MS study [12] on ozone surface decomposition on pyrex and quartz. Implications for atmospheric chemistry will be discussed. [1] Morton, J., Barnes, J., Schueler, B. and Mauersberger, K. J. Geophys. Res. 95, 901 - 907 (1990

  4. New 1,2,4-triazole-based azo-azomethine dyes. Part I: Synthesis, characterization and spectroscopic studies

    Science.gov (United States)

    Khanmohammadi, Hamid; Erfantalab, Malihe

    2012-02-01

    Four new 1,2,4-triazole-based azo-azomethine dyes were synthesized via condensation of 3,5-diamino-1,2,4-triazole with azo-coupled o-vanillin precursors. The prepared dyes were characterized by IR, UV-vis and 1H NMR spectroscopic methods as well as elemental analyses. Thermal properties of the prepared dyes were examined by thermogravimetric analysis. Results indicated that the framework of the dyes was stable up to 225 °C. Also, the influence of various factors including time and mixed DMSO/EtOH solution on UV-vis spectra of the dyes were investigated.

  5. Spectroscopic and microscopic characterization of portland cement based unleached and leached solidified waste

    Science.gov (United States)

    Salaita, Ghaleb N.; Tate, Philip H.

    1998-05-01

    In this study, portland cement based solidified/stabilized (S/S) waste and a cement-only control were studied before and after leaching. The solidified waste samples were prepared from a mix of organic-containing industrial waste sludge and portland cement. Toxicity characterization leaching procedure (TCLP) was the leaching test employed. The samples were studied using multi-surface analytical techniques including XPS, SIMS, XRD, FE-SEM and EDS. The data obtained from the various techniques show that leaching does not measurably affect the morphology or composition of the solidified waste sample. However, subtle changes in the composition of the cement control sample were observed. While the concentration of the elements observed on the surface of leached and unleached waste samples by XPS are very similar (except for Mg, Na and N), study of the corresponding cement samples exhibit differences in the level of C, Si, S, and Ca. The unleached cement sample shows lower levels of C and Si, but higher levels of O, S, Ca and Mg, indicating that leaching alters the cement sample. EDS analyses of the elemental composition of the bulk of the leached and unleached waste samples are similar, and also are similar for the leached and unleached cement samples, indicating that under the conditions of the TCLP test, leaching has no effect on the bulk. The high level of Ca present on the surface of the solidified waste indicates entrapment of the waste by the cement. The information and results obtained show that the surface analytical techniques used in this work, when combined with environmental wet methods, can provide a more complete picture of the concentration, chemical state and immobility of solidified waste.

  6. Molecular characterization of the plant biopolyester cutin by AFM and spectroscopic techniques.

    Science.gov (United States)

    Benítez, José J; Matas, Antonio J; Heredia, Antonio

    2004-08-01

    Atomic force microscopy, FT-IR spectroscopy, and solid-state nuclear magnetic resonance have been used to improve our current knowledge on the molecular characteristics of the biopolyester cutin, the main component of the plant cuticle. After comparison of samples of cutin isolated from young and mature tomato fruit cuticles has been possible to establish different degrees of cross-linking in the biopolymer and that the polymer is mainly formed after esterification of secondary hydroxyl groups of the monomers that form this type of cutin. Atomic force microscopy gave useful structural information on the molecular topography of the outer surface of the isolated samples. The texture of these samples is a consequence of the cross-linking degree or chemical status of the polymer. Thus, the more dense and cross-linked cutin from ripe or mature tomato fruit is characterized by a flatter and more globular texture in addition to the development of elongated and orientated superstructures.

  7. Characterization of Surface Modification of Polyethersulfone Membrane

    Science.gov (United States)

    Surface modification of polyethersulfone (PES) membrane surface using UV/ozone-treated grafting and interfacial polymerization on membrane surface was investigated in order to improve the resistance of membrane surface to protein adsorption. These methods of surface modification were compared in te...

  8. X-ray micro-beam characterization of a small pixel spectroscopic CdTe detector

    Science.gov (United States)

    Veale, M. C.; Bell, S. J.; Seller, P.; Wilson, M. D.; Kachkanov, V.

    2012-07-01

    A small pixel, spectroscopic, CdTe detector has been developed at the Rutherford Appleton Laboratory (RAL) for X-ray imaging applications. The detector consists of 80 × 80 pixels on a 250 μm pitch with 50 μm inter-pixel spacing. Measurements with an 241Am γ-source demonstrated that 96% of all pixels have a FWHM of better than 1 keV while the majority of the remaining pixels have FWHM of less than 4 keV. Using the Diamond Light Source synchrotron, a 10 μm collimated beam of monochromatic 20 keV X-rays has been used to map the spatial variation in the detector response and the effects of charge sharing corrections on detector efficiency and resolution. The mapping measurements revealed the presence of inclusions in the detector and quantified their effect on the spectroscopic resolution of pixels.

  9. Spectroscopic and thermal characterizations of Yb:LaF3 single crystal

    Science.gov (United States)

    Hong, Jiaqi; Zhang, Lianhan; Hang, Yin; Xu, Min

    2016-10-01

    A Yb3+ doped LaF3 laser crystal was detailed investigated by both spectroscopic and thermal measurements. A peak absorption at 974 nm with FWHM broader than 60 nm makes the crystal suitable to InGaAs LDs. Fluorescence spectrum and calculated spectroscopic parameters show potential of Yb:LaF3 crystal to laser operations around 1009 nm. A relatively long fluorescence lifetime of 2.92 ms was detected for Yb3+:2F5/2 manifold. The thermal diffusivity and specific heat capacity in the range of 300-575 K were studied to calculate the thermal conductivity of Yb:LaF3. The results indicate that the Yb:LaF3 crystal is a good candidate for diode-pumped ∼1 μm solid-state laser applications.

  10. Synthesis and spectroscopic characterization of high-spin mononuclear iron(II) p-semiquinonate complexes.

    Science.gov (United States)

    Baum, Amanda E; Park, Heaweon; Lindeman, Sergey V; Fiedler, Adam T

    2014-12-01

    Two mononuclear iron(II) p-semiquinonate (pSQ) complexes have been generated via one-electron reduction of precursor complexes containing a substituted 1,4-naphthoquinone ligand. Detailed spectroscopic and computational analysis confirmed the presence of a coordinated pSQ radical ferromagnetically coupled to the high-spin Fe(II) center. The complexes are intended to model electronic interactions between (semi)quinone and iron cofactors in biology.

  11. Synthesis and Spectroscopic Characterization of High-Spin Mononuclear Iron(II) p-Semiquinonate Complexes

    OpenAIRE

    Baum, Amanda E.; Park, Heaweon; Lindeman, Sergey V.; Fiedler, Adam T.

    2014-01-01

    Two mononuclear iron(II) p-semiquinonate (pSQ) complexes have been generated via one-electron reduction of precursor complexes containing a substituted 1,4-naphthoquinone ligand. Detailed spectroscopic and computational analysis confirmed the presence of a coordinated pSQ radical ferromagnetically coupled to the high-spin FeII center. The complexes are intended to model electronic interactions between (semi)quinone and iron cofactors in biology.

  12. Spectroscopic ellipsometry characterization of microwave CVD grown silicon nanoparticles embedded in a silicon nitride matrix

    Energy Technology Data Exchange (ETDEWEB)

    Keita, A-S; Naciri, A En [LPMD, Universite Paul Verlaine-Metz, 1 Bd Arago, 57070 Metz - France (France); Delachat, F; Carrada, M; Ferblantier, G; Slaoui, A, E-mail: alsaleh.keita@univ-metz.fr [InESS, CNRS/UdS, 23 rue du Loess, BP 20, 67037, Strasbourg Cedex 2 (France)

    2009-11-15

    Plasma Enhanced Vapour Deposition (PECVD) is used to elaborate silicon nanoparticles (np-Si) embedded in silicon nitride (Si{sub 3}N{sub 4}) layers. The samples have been produced for various NH{sub 3} flows. The np-Si dielectric function (DF) have been determined by spectroscopic ellipsometry (SE) in the wavelength range from 210 nm to 880 nm. Thanks to ellipsometric modeling it has been possible to study the np-Si physical properties.

  13. Mid-infrared vibrational spectroscopic characterization of 5,6-dihydroxyindole and eumelanin derived from it

    Science.gov (United States)

    Hyogo, Ryosuke; Nakamura, Atsushi; Okuda, Hidekazu; Wakamatsu, Kazumasa; Ito, Shosuke; Sota, Takayuki

    2011-12-01

    Mid-infrared vibrational spectroscopic study has been made on 5,6-dihydroxyindole (DHI) and DHI-derived eumelanin. It has been revealed for DHI monomer that measured infrared absorption spectrum is well reproduced by that predicted from ab initio calculations. Thus, vibrational modes of DHI monomer causing dominant absorption bands have been successfully assigned. It has been also reconfirmed that DHI-derived eumelanin includes indolequinone and/or quinone methide units in addition to DHI units.

  14. Anion pairs in room temperature ionic liquids predicted by molecular dynamics simulation, verified by spectroscopic characterization

    Energy Technology Data Exchange (ETDEWEB)

    Schwenzer, Birgit; Kerisit, Sebastien N.; Vijayakumar, M.

    2014-01-01

    Molecular-level spectroscopic analyses of an aprotic and a protic room-temperature ionic liquid, BMIM OTf and BMIM HSO4, respectively, have been carried out with the aim of verifying molecular dynamics simulations that predict anion pair formation in these fluid structures. Fourier-transform infrared spectroscopy, Raman spectroscopy and nuclear magnetic resonance spectroscopy of various nuclei support the theoretically-determined average molecular arrangements.

  15. Spectroscopic characterization and docking studies of ZnO nanoparticle modified with BSA

    Science.gov (United States)

    Ledesma, Ana E.; Chemes, Doly María; Frías, María de los Angeles; Guauque Torres, Maria del Pilar

    2017-08-01

    Nanoparticles (NP) into a biological environment are an interesting topic for diagnosis and therapy in applications for medicine or environment and the knowledge about this interaction is important from the perspective of safe use of nanomaterials. In the current study, we characterized the type of interaction and the orientation of bovine serum albumin (BSA) adsorbed on ZnO nanoparticle surfaces as a function of size, using molecular docking. To probe experimentally different theoretical hypothesis about the interaction, ZnO-NPs were prepared in aqueous solution, and then were bioconjugated with BSA. Transmission electron microscopy (TEM) and Raman spectroscopy confirm the spherical shape of NP and the irreversible adsorption of BSA on NP surface. Raman and Infrared spectroscopy (FTIR) reveal that BSA interaction with ZnO nanoparticle produced a conformational rearrangement into protein, observing changes in Tyr and Trp environment, a minor percentage of α-helix structure and a more extended chain. The fluorescence analysis demonstrated that when BSA concentration higher than 30 μM is used the signal due to the self-oligomerization of protein overlaps with the ZnO nanoparticle emission. The results predicted that the most probable interaction site is near to domain IB and IIA and ionic interactions are the major responsible for the binding. Thermal stability studies reveals that the denaturalization temperature of BSA increase from 57 °C to 65 °C in presence of ZnO NP and their esterase-like activity was improved.

  16. Characterization and robust filtering of multifunctional surfaces using ISO standards

    DEFF Research Database (Denmark)

    Friis, Kasper Storgaard; Godi, Alessandro; De Chiffre, Leonardo

    2011-01-01

    to the multi-process production method involved. A series of MUFU surfaces were characterized by using the ISO 13565 standard for stratified surfaces and it is shown that the standard in some cases is inadequate for the characterization of a MUFU surface. To improve the filtering of MUFU surfaces, the robust...... Gaussian regression filtering technique described in ISO 16610-31 is analyzed and discussed. By slight modifications it is shown how the robust Gaussian regression filter can be applied to remove the form and find a suitable reference surface for further characterization of the MUFU surfaces...

  17. The Application of Marker Based Segmentation for Surface Texture Characterization

    Directory of Open Access Journals (Sweden)

    Che Pin Nuraini binti

    2016-01-01

    Full Text Available Structured surfaces have been increasingly used in industry for a variety of applications, including improving the tribological properties of the surfaces. Surface metrology plays an important role in this discipline since with the help of surface metrology technology, surface texture can be measured, visualize and quantified. Traditional surface texture parameters, such as roughness and waviness, cannot be related to the function for structured surfaces due to the less statistical description and little information. Therefore, a new approaches based on characterizing the structured surface is introduces where this paper focus on type of edges grain surface. To identify features, it is a must to detect the location of the edges and segmented the features based on the detected edges. Hence characterization of surface texture segmentation based on the edges detection is developing using Marker Based segmentation and it is prove that this method is possible to be used in order to characterize the structured surface.

  18. Surface enhanced Raman spectroscopic studies on aspirin : An experimental and theoretical approach

    Science.gov (United States)

    Premkumar, R.; Premkumar, S.; Rekha, T. N.; Parameswari, A.; Mathavan, T.; Benial, A. Milton Franklin

    2016-05-01

    Surface enhanced Raman scattering (SERS) studies on aspirin molecule adsorbed on silver nanoparticles (AgNPs) were investigated by experimental and density functional theory approach. The AgNPs were synthesized by the solution-combustion method and characterized by the X-ray diffraction and high resolution-transmission electron microscopy techniques. The averaged particle size of synthesized AgNPs was calculated as ˜55 nm. The normal Raman spectrum (nRs) and SERS spectrum of the aspirin were recorded. The molecular structure of the aspirin and aspirin adsorbed on silver cluster were optimized by the DFT/ B3PW91 method with LanL2DZ basis set. The vibrational frequencies were calculated and assigned on the basis of potential energy distribution calculation. The calculated nRs and SERS frequencies were correlated well with the observed frequencies. The flat-on orientation was predicted from the nRs and SERS spectra, when the aspirin adsorbed on the AgNPs. Hence, the present studies lead to the understanding of adsorption process of aspirin on the AgNPs, which paves the way for biomedical applications.

  19. Surface enhanced Raman spectroscopic studies on aspirin : An experimental and theoretical approach

    Energy Technology Data Exchange (ETDEWEB)

    Premkumar, R.; Premkumar, S.; Parameswari, A.; Mathavan, T.; Benial, A. Milton Franklin, E-mail: miltonfranklin@yahoo.com [Department of Physics, N.M.S.S.V.N College, Madurai-625019, Tamilnadu, India. (India); Rekha, T. N. [PG and Research Department of Physics, Lady Doak College, Madurai-625 002, Tamilnadu, India. (India)

    2016-05-06

    Surface enhanced Raman scattering (SERS) studies on aspirin molecule adsorbed on silver nanoparticles (AgNPs) were investigated by experimental and density functional theory approach. The AgNPs were synthesized by the solution-combustion method and characterized by the X-ray diffraction and high resolution-transmission electron microscopy techniques. The averaged particle size of synthesized AgNPs was calculated as ∼55 nm. The normal Raman spectrum (nRs) and SERS spectrum of the aspirin were recorded. The molecular structure of the aspirin and aspirin adsorbed on silver cluster were optimized by the DFT/ B3PW91 method with LanL2DZ basis set. The vibrational frequencies were calculated and assigned on the basis of potential energy distribution calculation. The calculated nRs and SERS frequencies were correlated well with the observed frequencies. The flat-on orientation was predicted from the nRs and SERS spectra, when the aspirin adsorbed on the AgNPs. Hence, the present studies lead to the understanding of adsorption process of aspirin on the AgNPs, which paves the way for biomedical applications.

  20. Surface roughness estimation of MBE grown CdTe/GaAs(211)B by ex-situ spectroscopic ellipsometry

    Science.gov (United States)

    Karakaya, Merve; Bilgilisoy, Elif; Arı, Ozan; Selamet, Yusuf

    2016-07-01

    Spectroscopic ellipsometry (SE) ranging from 1.24 eV to 5.05 eV is used to obtain the film thickness and optical properties of high index (211) CdTe films. A three-layer optical model (oxide/CdTe/GaAs) was chosen for the ex-situ ellipsometric data analysis. Surface roughness cannot be determined by the optical model if oxide is included. We show that roughness can be accurately estimated, without any optical model, by utilizing the correlation between SE data (namely the imaginary part of the dielectric function, or phase angle, ψ) and atomic force microscopy (AFM) roughness. and ψ values at 3.31 eV, which corresponds to E1 critical transition energy of CdTe band structure, are chosen for the correlation since E1 gives higher resolution than the other critical transition energies. On the other hand, due to the anisotropic characteristic of (211) oriented CdTe surfaces, SE data ( and ψ) shows varieties for different azimuthal angle measurements. For this reason, in order to estimate the surface roughness by considering these correlations, it is shown that SE measurements need to be taken at the same surface azimuthal angle. Estimating surface roughness in this manner is an accurate way to eliminate cumbersome surface roughness measurement by AFM.

  1. NMR characterization of hydrocarbon adsorption on calcite surfaces: A first principles study

    Energy Technology Data Exchange (ETDEWEB)

    Bevilaqua, Rochele C. A.; Miranda, Caetano R. [Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, UFABC, Santo André, SP (Brazil); Rigo, Vagner A. [Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, UFABC, Santo André, SP (Brazil); Universidade Tecnológica Federal do Paraná, UTFPR, Cornélio Procópio, PR (Brazil); Veríssimo-Alves, Marcos [Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, UFABC, Santo André, SP (Brazil); Departamento de Física, ICEx, Universidade Federal Fluminense, UFF, Volta Redonda, RJ (Brazil)

    2014-11-28

    The electronic and coordination environment of minerals surfaces, as calcite, are very difficult to characterize experimentally. This is mainly due to the fact that there are relatively few spectroscopic techniques able to detect Ca{sup 2+}. Since calcite is a major constituent of sedimentary rocks in oil reservoir, a more detailed characterization of the interaction between hydrocarbon molecules and mineral surfaces is highly desirable. Here we perform a first principles study on the adsorption of hydrocarbon molecules on calcite surface (CaCO{sub 3} (101{sup ¯}4)). The simulations were based on Density Functional Theory with Solid State Nuclear Magnetic Resonance (SS-NMR) calculations. The Gauge-Including Projector Augmented Wave method was used to compute mainly SS-NMR parameters for {sup 43}Ca, {sup 13}C, and {sup 17}O in calcite surface. It was possible to assign the peaks in the theoretical NMR spectra for all structures studied. Besides showing different chemical shifts for atoms located on different environments (bulk and surface) for calcite, the results also display changes on the chemical shift, mainly for Ca sites, when the hydrocarbon molecules are present. Even though the interaction of the benzene molecule with the calcite surface is weak, there is a clearly distinguishable displacement of the signal of the Ca sites over which the hydrocarbon molecule is located. A similar effect is also observed for hexane adsorption. Through NMR spectroscopy, we show that aromatic and alkane hydrocarbon molecules adsorbed on carbonate surfaces can be differentiated.

  2. Ghanaian cocoa bean fermentation characterized by spectroscopic and chromatographic methods and chemometrics.

    Science.gov (United States)

    Aculey, Patrick C; Snitkjaer, Pia; Owusu, Margaret; Bassompiere, Marc; Takrama, Jemmy; Nørgaard, Lars; Petersen, Mikael A; Nielsen, Dennis S

    2010-08-01

    Export of cocoa beans is of great economic importance in Ghana and several other tropical countries. Raw cocoa has an astringent, unpleasant taste, and flavor, and has to be fermented, dried, and roasted to obtain the characteristic cocoa flavor and taste. In an attempt to obtain a deeper understanding of the changes in the cocoa beans during fermentation and investigate the possibility of future development of objective methods for assessing the degree of fermentation, a novel combination of methods including cut test, colorimetry, fluorescence spectroscopy, NIR spectroscopy, and GC-MS evaluated by chemometric methods was used to examine cocoa beans sampled at different durations of fermentation and samples representing fully fermented and dried beans from all cocoa growing regions of Ghana. Using colorimetry it was found that samples moved towards higher a* and b* values as fermentation progressed. Furthermore, the degree of fermentation could, in general, be well described by the spectroscopic methods used. In addition, it was possible to link analysis of volatile compounds with predictions of fermentation time. Fermented and dried cocoa beans from the Volta and the Western regions clustered separately in the score plots based on colorimetric, fluorescence, NIR, and GC-MS indicating regional differences in the composition of Ghanaian cocoa beans. The study demonstrates the potential of colorimetry and spectroscopic methods as valuable tools for determining the fermentation degree of cocoa beans. Using GC-MS it was possible to demonstrate the formation of several important aroma compounds such 2-phenylethyl acetate, propionic acid, and acetoin and the breakdown of others like diacetyl during fermentation. Practical Application: The present study demonstrates the potential of using colorimetry and spectroscopic methods as objective methods for determining cocoa bean quality along the processing chain. Development of objective methods for determining cocoa bean

  3. Multiparametric Characterization of Grade 2 Glioma Subtypes Using Magnetic Resonance Spectroscopic, Perfusion, and Diffusion Imaging1

    Science.gov (United States)

    Bian, Wei; Khayal, Inas S; Lupo, Janine M; McGue, Colleen; Vandenberg, Scott; Lamborn, Kathleen R; Chang, Susan M; Cha, Soonmee; Nelson, Sarah J

    2009-01-01

    BACKGROUND AND PURPOSE: The purpose of this study was to derive quantitative parameters from magnetic resonance (MR) spectroscopic, perfusion, and diffusion imaging of grade 2 gliomas according to the World Health Organization and to investigate how these multiple imaging modalities can contribute to evaluating their histologic subtypes and spatial characteristics. MATERIALS AND METHODS: MR spectroscopic, perfusion, and diffusion images from 56 patients with newly diagnosed grade 2 glioma (24 oligodendrogliomas, 18 astrocytomas, and 14 oligoastrocytomas) were retrospectively studied. Metabolite intensities, relative cerebral blood volume (rCBV), and apparent diffusion coefficient (ADC) were statistically evaluated. RESULTS: The 75th percentile rCBV and median ADC were significantly different between oligodendrogliomas and astrocytomas (P < .0001) and between oligodendrogliomas and oligoastrocytomas (P < .001). Logistic regression analysis identified both 75th percentile rCBV and median ADC as significant variables in the differentiation of oligodendrogliomas from astrocytomas and oligoastrocytomas. Group differences in metabolite intensities were not significant, but there was a much larger variation in the volumes and maximum values of metabolic abnormalities for patients with oligodendroglioma compared with the other tumor subtypes. CONCLUSIONS: Perfusion and diffusion imaging provide quantitative MR parameters that can help to differentiate grade 2 oligodendrogliomas from grade 2 astrocytomas and oligoastrocytomas. The large variations in the magnitude and spatial extent of the metabolic lesions between patients and the fact that their values are not correlated with the other imaging parameters indicate that MR spectroscopic imaging may provide complementary information that is helpful in targeting therapy, evaluating residual disease, and assessing response to therapy. PMID:19956389

  4. Synthesis, spectroscopic and computational characterization of the tautomerism of pyrazoline derivatives from chalcones.

    Science.gov (United States)

    Miguel, Fábio Balbino; Dantas, Juliana Arantes; Amorim, Stefany; Andrade, Gustavo F S; Costa, Luiz Antônio Sodré; Couri, Mara Rubia Costa

    2016-01-05

    In the present study a series of novel pyrazolines derivatives has been synthesized, and their structures assigned on the basis of FT-Raman, (1)H and (13)C NMR spectral data and computational DFT calculations. A joint computational study using B3LYP/6-311G(2d,2p) density functional theory and FT-Raman investigation on the tautomerism of 3-(4-substituted-phenyl)-4,5-dihydro-5-(4-substituted-phenyl)pyrazole-1-carbothioamide and 3-(4-substituted-phenyl)-4,5-dihydro-5-(4-substituted-phenyl)pyrazole-1-carboxamide are presented. The structures were characterized as a minimum in the potential energy surface using DFT. The calculated Raman and NMR spectra were of such remarkable agreement to the experimental results that the equilibrium between tautomeric forms has been discussed in detail. Our study suggests the existence of tautomers, the carboxamide/carbothioamide group may tautomerize, in the solid state or in solution. Thermodynamic data calculated suggests that the R(CS)NH2 and R(CO)NH2 species are more stable than the R(CNH)SH and R(CNH)OH species. Additionally, results found for the (1)H NMR shifting, pointed out to which structure is present.

  5. Synthesis, spectroscopic and computational characterization of the tautomerism of pyrazoline derivatives from chalcones

    Science.gov (United States)

    Miguel, Fábio Balbino; Dantas, Juliana Arantes; Amorim, Stefany; Andrade, Gustavo F. S.; Costa, Luiz Antônio Sodré; Couri, Mara Rubia Costa

    2016-01-01

    In the present study a series of novel pyrazolines derivatives has been synthesized, and their structures assigned on the basis of FT-Raman, 1H and 13C NMR spectral data and computational DFT calculations. A joint computational study using B3LYP/6-311G(2d,2p) density functional theory and FT-Raman investigation on the tautomerism of 3-(4-substituted-phenyl)-4,5-dihydro-5-(4-substituted-phenyl)pyrazole-1-carbothioamide and 3-(4-substituted-phenyl)-4,5-dihydro-5-(4-substituted-phenyl)pyrazole-1-carboxamide are presented. The structures were characterized as a minimum in the potential energy surface using DFT. The calculated Raman and NMR spectra were of such remarkable agreement to the experimental results that the equilibrium between tautomeric forms has been discussed in detail. Our study suggests the existence of tautomers, the carboxamide/carbothioamide group may tautomerize, in the solid state or in solution. Thermodynamic data calculated suggests that the R(Cdbnd S)NH2 and R(Cdbnd O)NH2 species are more stable than the R(Cdbnd NH)SH and R(Cdbnd NH)OH species. Additionally, results found for the 1H NMR shifting, pointed out to which structure is present.

  6. Biochemical, Mechanistic, and Spectroscopic Characterization of Metallo-β-lactamase VIM-2

    Energy Technology Data Exchange (ETDEWEB)

    Aitha, Mahesh [Miami Univ., Oxford, OH (United States); Marts, Amy R. [Miami Univ., Oxford, OH (United States); Bergstrom, Alex [Miami Univ., Oxford, OH (United States); Møller, Abraham Jon [Miami Univ., Oxford, OH (United States); Moritz, Lindsay [Miami Univ., Oxford, OH (United States); Turner, Lucien [Miami Univ., Oxford, OH (United States); Nix, Jay C. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Bonomo, Robert A. [Louis Stokes Cleveland Dept. of Veterans Affairs Medical Center, Cleveland, OH (United States); Case Western Reserve Univ., Cleveland, OH (United States); Page, Richard C. [Miami Univ., Oxford, OH (United States); Tierney, David L. [Miami Univ., Oxford, OH (United States); Crowder, Michael W. [Miami Univ., Oxford, OH (United States)

    2014-11-25

    Our study examines metal binding to metallo-β-lactamase VIM-2, demonstrating the first successful preparation of a Co(II)-substituted VIM-2 analogue. Spectroscopic studies of the half- and fully metal loaded enzymes show that both Zn(II) and Co(II) bind cooperatively, where the major species present, regardless of stoichiometry, are apo- and di-Zn (or di-Co) enzymes. We also determined the di-Zn VIM-2 structure to a resolution of 1.55 Å, and this structure supports results from spectroscopic studies. Kinetics, both steady-state and pre-steady-state, show that VIM-2 utilizes a mechanism that proceeds through a very short-lived anionic intermediate when chromacef is used as the substrate. Comparison with other B1 enzymes shows that those that bind Zn(II) cooperatively are better poised to protonate the intermediate on its formation, compared to those that bind Zn(II) non-cooperatively, which uniformly build up substantial amounts of the intermediate.

  7. The optical characterization of organometallic complex thin films by spectroscopic ellipsometry and photovoltaic diode application

    Energy Technology Data Exchange (ETDEWEB)

    Özaydın, C. [Batman University, Engineering Faculty, Department of Computer Eng., Batman (Turkey); Güllü, Ö., E-mail: omergullu@gmail.com [Batman University, Science and Art Faculty, Department of Physics, Batman (Turkey); Pakma, O. [Batman University, Science and Art Faculty, Department of Physics, Batman (Turkey); Ilhan, S. [Siirt University, Science and Art Faculty, Department of Chemistry, Siirt (Turkey); Akkılıç, K. [Dicle University, Education Faculty, Department of Physics Education, Diyarbakır (Turkey)

    2016-05-15

    Highlights: • Optical properties and thickness of the A novel organometallic complex (OMC) film were investigated by spectroscopic ellipsometry (SE). • Au/OMC/n-Si metal/interlayer/semiconductor (MIS) diode has been fabricated • This paper presents the I–V analysis of Au/OMC/n-Si MIS diode. • Current–voltage and photovoltaic properties of the diode were investigated. - Abstract: In this work, organometallic complex (OMC) films have been deposited onto glass or silicon substrates by spin coating technique and their photovoltaic application potential has been investigated. Optical properties and thickness of the film have been investigated by spectroscopic ellipsometry (SE). Also, transmittance spectrum has been taken by UV/vis spectrophotometer. The optical method has been used to determine the band gap value of the films. Also, Au/OMC/n-Si metal/interlayer/semiconductor (MIS) diode has been fabricated. Current–voltage and photovoltaic properties of the structure were investigated. The ideality factor (n) and barrier height (Φ{sub b}) values of the diode were found to be 2.89 and 0.79 eV, respectively. The device shows photovoltaic behavior with a maximum open-circuit voltage of 396 mV and a short circuit current of 33.8 μA under 300 W light.

  8. Spectroscopic characterization of the quantum wires in titanosilicates ETS-4 and ETS-10

    Energy Technology Data Exchange (ETDEWEB)

    Yilmaz, Bilge; Warzywoda, Juliusz; Sacco, Albert Jr [Center for Advanced Microgravity Materials Processing, Department of Chemical Engineering, Northeastern University, 147 Snell Engineering Center, Boston, MA 02115 (United States)

    2006-08-28

    Titanosilicates ETS-4 and ETS-10 contain octahedrally coordinated monatomic semiconductor ...Ti-O-Ti-O-Ti... (titania) chains in their frameworks. Titania chains are isolated from one another by a siliceous matrix. Thus, these chains can be regarded as one-dimensional nanostructures, i.e., 'quantum wires'. Diffuse reflectance UV-vis (DR-UV-vis) spectroscopy analysis demonstrated a significant blue-shift of the optical absorption edge (>60 nm) for both ETS-4 and ETS-10 compared to bulk titania. This blue-shift is consistent with the hypothesis that the titania chains in ETS-4 and ETS-10 are acting as quantum wires. A broad range of ETS-4 and ETS-10 samples with diverse crystallo-chemical characteristics was prepared. The DR-UV-vis and Raman spectra of various ETS-4 and ETS-10 samples exhibited different characteristics, which were hypothesized to be related to the titania chain 'quality'. Detailed investigation of the spectroscopic bands associated with the titania chains in ETS-4 was performed for the first time. The 'quality' of these titania chains/quantum wires in ETS-4 and ETS-10 was correlated with the crystal growth mechanisms of these materials. Comparison of the growth mechanisms and the spectroscopic behaviour for ETS-4 and ETS-10 suggests that the control of 'quantum wire quality' via hydrothermal synthesis is possible in ETS-4 but would be difficult in ETS-10.

  9. Expression in Escherichia coli, purification, and spectroscopic characterization of two mutant Bet v 1 proteins.

    Science.gov (United States)

    Boehm, M; Rösch, P

    1997-07-01

    Bet v 1 is the major birch pollen allergen. A highly efficient expression and purification scheme for mutant forms of this protein was developed on the basis of the pET expression system in order to provide the high quantities of protein needed for spectroscopic and structural work. Bet v 1 (M139L) protein could be purified at high yield (approx. 30 mg from 1 liter of LB medium) in a two-step procedure by the use of metal-affinity chromatography. Matrix assisted laser desorption ionisation mass spectroscopy, and size exclusion chromatography demonstrate the homogeneity and purity of the prepared protein. Spectroscopic methods were used to show that Bet v 1 (M139L) is structurally similar to wild type Bet v 1. Furthermore, we investigated the influence of the nature of amino acid 139 on the thermodynamic behaviour of the protein by replacing the leucine residue by alanine. While there appears to be no global structural effect of this mutation, the thermostability of Bet v 1 is greatly decreased.

  10. A microfluidic surface enhanced Raman spectroscopic biosensor using aptamer functionalized nanopillars

    DEFF Research Database (Denmark)

    Yang, J.; Palla, M.; Bosco, F. G.

    2013-01-01

    This paper presents a microchip incorporating an aptamer-functionalized nanopillar substrate, enabling the specific detection of low-abundance biomolecules using surface enhanced Raman spectroscopy (SERS). In a temperature controlled microchamber, aptamers immobilized on the nanostructure surface...

  11. Characterization techniques for surface-micromachined devices

    Energy Technology Data Exchange (ETDEWEB)

    Eaton, W.P.; Smith, N.F.; Irwin, L.; Tanner, D.M.

    1998-08-01

    Using a microengine as the primary test vehicle, the authors have examined several aspects of characterization. Parametric measurements provide fabrication process information. Drive signal optimization is necessary for increased microengine performance. Finally, electrical characterization of resonant frequency and quality factor can be more accurate than visual techniques.

  12. [Study on spectroscopic characterization and property of PES/ micro-nano cellulose composite membrane material].

    Science.gov (United States)

    Tang, Huan-Wei; Zhang, Li-Ping; Li, Shuai; Zhao, Guang-Jie; Qin, Zhu; Sun, Su-Qin

    2010-03-01

    In the present paper, the functional groups of PES/micro-nano cellulose composite membrane materials were characterized by Fourier transform infrared spectroscopy (FTIR). Also, changes in crystallinity in composite membrane materials were analyzed using X-ray diffraction (XRD). The effects of micro-nano cellulose content on hydrophilic property of composite membrane material were studied by measuring hydrophilic angle. The images of support layer structure of pure PES membrane material and composite membrane material were showed with scanning electron microscope (SEM). These results indicated that in the infrared spectrogram, the composite membrane material had characteristic peaks of both PES and micro-nano cellulose without appearance of other new characteristics peaks. It revealed that there were no new functional groups in the composite membrane material, and the level of molecular compatibility was achieved, which was based on the existence of inter-molecular hydrogen bond association between PES and micro-nano cellulose. Due to the existence of micro-nano cellulose, the crystallinity of composite membrane material was increased from 37.7% to 47.9%. The more the increase in micro-nano cellulose mass fraction, the better the van de Waal force and hydrogen bond force between composite membrane material and water were enhanced. The hydrophilic angle of composite membrane material was decreased from 55.8 degrees to 45.8 degrees and the surface energy was raised from 113.7 to 123.5 mN x m(-2). Consequently, the hydrophilic property of composite membrane material was improved. The number of pores in the support layer of composite membrane material was lager than that of pure PES membrane. Apparently, pores were more uniformly distributed.

  13. Thermomorphic phase separation in ionic liquid-organic liquid systems--conductivity and spectroscopic characterization.

    Science.gov (United States)

    Riisager, Anders; Fehrmann, Rasmus; Berg, Rolf W; van Hal, Roy; Wasserscheid, Peter

    2005-08-21

    Electrical conductivity, FT-Raman and NMR measurements are demonstrated as useful tools to probe and determine phase behavior of thermomorphic ionic liquid-organic liquid systems. To illustrate the methods, consecutive conductivity measurements of a thermomorphic methoxyethoxyethyl-imidazolium ionic liquid/1-hexanol system are performed in the temperature interval 25-80 degrees C using a specially constructed double-electrode cell. In addition, FT-Raman and 1H-NMR spectroscopic studies performed on the phase-separable system in the same temperature interval confirm the mutual solubility of the components in the system, the liquid-liquid equilibrium phase diagram of the binary mixture, and signify the importance of hydrogen bonding between the ionic liquid and the hydroxyl group of the alcohol.

  14. Spectroscopic characterization and quantitative determination of atorvastatin calcium impurities by novel HPLC method

    Science.gov (United States)

    Gupta, Lokesh Kumar

    2012-11-01

    Seven process related impurities were identified by LC-MS in the atorvastatin calcium drug substance. These impurities were identified by LC-MS. The structure of impurities was confirmed by modern spectroscopic techniques like 1H NMR and IR and physicochemical studies conducted by using synthesized authentic reference compounds. The synthesized reference samples of the impurity compounds were used for the quantitative HPLC determination. These impurities were detected by newly developed gradient, reverse phase high performance liquid chromatographic (HPLC) method. The system suitability of HPLC analysis established the validity of the separation. The analytical method was validated according to International Conference of Harmonization (ICH) with respect to specificity, precision, accuracy, linearity, robustness and stability of analytical solutions to demonstrate the power of newly developed HPLC method.

  15. Characterization of the SEI on a carbon film electrode by combinedEQCM and spectroscopic ellipsometry

    Energy Technology Data Exchange (ETDEWEB)

    evans@socrates.berkeley.edu

    2002-01-01

    The electrochemical quartz crystal microbalance (EQCM) andcyclic voltammetry have been applied simultaneously to characterizeelectron-beam deposited carbon film electrodes in LiClO4 orLiPF6-containing mixed electrolytes of ethylene carbonate (EC) anddimethyl carbonate (DMC). The structure of the carbon electrode was foundto be amorphous/disordered using Raman spectroscopy. Cyclic voltammetryin LiClO4 / EC+DMC demonstrated features typical of Liintercalation/deintercalation into/from the disordered carbon electrode,and EQCM showed a corresponding mass increase/decrease. Contrary to thecase of LiClO4 / EC+DMC electrolyte, LiPF6/EC+DMC electrolyte showed noLi deintercalation out of the thin-film carbon electrode. Combined EQCMand spectroscopic ellipsometry data were compared, and the solidelectrolyte interphase density after the first cycle in LiClO4 /EC+DMCwas estimated to be 1.3 g/cm3.

  16. Conformational, electronic, and spectroscopic characterization of isophthalic acid (monomer and dimer structures) experimentally and by DFT.

    Science.gov (United States)

    Bardak, F; Karaca, C; Bilgili, S; Atac, A; Mavis, T; Asiri, A M; Karabacak, M; Kose, E

    2016-08-05

    Isophthalic acid (C6H4(CO2H)2) is a noteworthy organic compound widely used in coating and synthesis of resins and the production of commercially important polymers such as drink plastic bottles. The effects of isophthalic acid (IPA) on human health, toxicology, and biodegradability are the main focus of many researchers. Because structural and spectroscopic investigation of molecules provides a deep understanding of interactional behaviors of compounds, this study stands for exploring those features. Therefore, the spectroscopic, structural, electronic, and thermodynamical properties of IPA were thoroughly studied in this work experimentally using UV-Vis, (1)H and (13)C NMR, FT-IR, FT-Raman and theoretically via DFT and TD-DFT calculations. The UV-Vis absorption spectrum in water was taken in the region 200-400nm. The NMR chemical shifts ((1)H and (13)C) were recorded in DMSO solution. The infrared and Raman spectra of the solid IPA were recorded in the range of 4000-400cm(-1) and 3500-50cm(-1), respectively. DFT and TD-DFT calculations were performed at the level of B3LYP/6-311++G(d,p) in determination of geometrical structure, electronic structure analysis and normal mode. The (13)C and (1)H nuclear magnetic resonance (NMR) spectra were estimated by using the gauge-invariant atomic orbital (GIAO) method. The scaled quantum mechanics (SQM) method was used to determine the total energy distribution (TED) to assign the vibrational modes accurately. Weak interactions such as hydrogen bonding and Van der Walls were analyzed via reduced density gradient (RDG) analysis in monomeric and dimeric forms. Furthermore, the excitation energies, density of state (DOS) diagram, thermodynamical properties, molecular electro-static potential (MEP), and nonlinear optical (NLO) properties were obtained.

  17. Conformational, electronic, and spectroscopic characterization of isophthalic acid (monomer and dimer structures) experimentally and by DFT

    Science.gov (United States)

    Bardak, F.; Karaca, C.; Bilgili, S.; Atac, A.; Mavis, T.; Asiri, A. M.; Karabacak, M.; Kose, E.

    2016-08-01

    Isophthalic acid (C6H4(CO2H)2) is a noteworthy organic compound widely used in coating and synthesis of resins and the production of commercially important polymers such as drink plastic bottles. The effects of isophthalic acid (IPA) on human health, toxicology, and biodegradability are the main focus of many researchers. Because structural and spectroscopic investigation of molecules provides a deep understanding of interactional behaviors of compounds, this study stands for exploring those features. Therefore, the spectroscopic, structural, electronic, and thermodynamical properties of IPA were thoroughly studied in this work experimentally using UV-Vis, 1H and 13C NMR, FT-IR, FT-Raman and theoretically via DFT and TD-DFT calculations. The UV-Vis absorption spectrum in water was taken in the region 200-400 nm. The NMR chemical shifts (1H and 13C) were recorded in DMSO solution. The infrared and Raman spectra of the solid IPA were recorded in the range of 4000-400 cm- 1 and 3500-50 cm- 1, respectively. DFT and TD-DFT calculations were performed at the level of B3LYP/6-311++G(d,p) in determination of geometrical structure, electronic structure analysis and normal mode. The 13C and 1H nuclear magnetic resonance (NMR) spectra were estimated by using the gauge-invariant atomic orbital (GIAO) method. The scaled quantum mechanics (SQM) method was used to determine the total energy distribution (TED) to assign the vibrational modes accurately. Weak interactions such as hydrogen bonding and Van der Walls were analyzed via reduced density gradient (RDG) analysis in monomeric and dimeric forms. Furthermore, the excitation energies, density of state (DOS) diagram, thermodynamical properties, molecular electro-static potential (MEP), and nonlinear optical (NLO) properties were obtained.

  18. Characterizing the interaction between oridonin and bovine serum albumin by a hybrid spectroscopic approach

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhen [Department of Chemistry, Shantou University, Shantou 515063 (China); Chen, Junhui, E-mail: chenjupush@126.com [Interventional Oncology and Minimally Invasive Therapies Department, Peking University Shenzhen Hospital, Shenzhen 518036 (China); Wang, Shaobin [The Fourth People' s Hospital of Shenzhen, Shenzhen 518033 (China); Chen, Zhanguang, E-mail: kqlu@stu.edu.cn [Department of Chemistry, Shantou University, Shantou 515063 (China)

    2013-02-15

    Oridonin is an effective anticancer drug which has high potency and low systemic toxicity. In this study, the interaction between oridonin and bovine serum albumin (BSA) was investigated by several spectroscopic approaches for the first time. The binding characteristics of oridonin and BSA were determined by fluorescence emission spectra and resonance light scattering spectra. It is showed that the oridonin quenches the fluorescence of BSA and the static quenching constant K{sub SV} is 1.30 Multiplication-Sign 10{sup 4} L mol{sup -1} at 298 K. Moreover, oridonin and BSA form a 1:1 complex with a binding constant of 0.62 Multiplication-Sign 10{sup 4} L mol{sup -1}. On the other hand, the thermodynamic parameters indicate that the binding process was a spontaneous molecular interaction procedure, in which hydrophobic forces played a major role. The structure analysis indicates that oridonin binding results in an increased hydrophobicity around the tryptophan residues of BSA. Additionally, as shown by the UV-vis absorption, synchronous fluorescence and three-dimensional fluorescence results, oridonin could lead to conformational and some microenvironmental changes of BSA. The work provides accurate and full basic data for clarifying the binding mechanism of oridonin with BSA in vitro and is helpful for understanding its effect on protein function during its transportation and distribution in blood. - Highlights: Black-Right-Pointing-Pointer Interaction between oridonin and BSA was evaluated by multi-spectroscopic methods. Black-Right-Pointing-Pointer Binding constant, number of binding sites and thermodynamic parameters were calculated. Black-Right-Pointing-Pointer Oridonin binds to Subdomain II site in BSA and form a 1:1 complex with it. Black-Right-Pointing-Pointer Oridonin-BSA complex is stabilized mainly by hydrophobic force. Black-Right-Pointing-Pointer Oridonin binding induces conformational and microenvironmental changes in BSA.

  19. The effect of shape anisotropy on the spectroscopic characterization of the magneto-optical activity of nanostructures

    CERN Document Server

    Du, Guan-Xiang; Takahashi, Migaku

    2013-01-01

    How to measure magnetic field induced magneto-optical (MO) activity of nonmagnetic elliptical plasmonic nanodisks which rest on a dielectric substrate remains a challenge since the substrate contribute most of the overall MO which varies with light polarization with respect to the orientation of the nanodisks. Here we present a spectroscopic characterization. We find that only when light is incident from the nanostructures side with polarization aligned with one of the two symmetry axes, one can subtract the MO contribution from the substrate by an amount equal to that of a bare one. By a detailed polarizing transmittance measurement we determine the orientation of the two symmetry axes of the nanodisks. Light polarization is then aligned along the axes, enabling measurement of the intrinsic MO activity of gold nanodisks, which is the overall MO activity subtracted by that of a bare glass substrate. The narrow line widths of the plasmonic resonance features in the MO spectra imply a potential application in r...

  20. Semiconductor Surface Characterization by Scanning Probe Microscopies

    Science.gov (United States)

    2001-01-01

    potentiometry (STP)8 and ballistic electron emission microscopy (BEEM)9 which allow mapping of lateral surface potential and local subsurface Schottky...A.P.Fein. "Tunneling Spectroscopy of the Si(1 1 1)2xl Surface", Surf.Sci. 181, 295- 306, 1987. 8. P.Muralt, D.W.Pohl, "Scanning tunneling potentiometry

  1. Egypt satellite images for land surface characterization

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay

    Satellite images provide information on the land surface properties. From optical remote sensing images in the blue, green, red and near-infrared part of the electromagnetic spectrum it is possible to identify a large number of surface features. The report briefly describes different satellite...

  2. In situ surface-enhanced Raman spectroscopic study of formic acid electrooxidation on spontaneously deposited platinum on gold.

    Science.gov (United States)

    Muralidharan, Ranjani; McIntosh, Michael; Li, Xiao

    2013-06-28

    Present formic acid fuel cell efficiency is limited by low kinetics at the anode, indicating the need for effective catalysts to improve the formic acid oxidation. As a prerequisite, the nature of adsorbed species and specifically the reaction intermediates formed in this process needs to be examined. This work focuses on the electrooxidation of formic acid and the nature of the intermediates at a platinum-modified gold surface prepared through spontaneous deposition using a combination of electrochemistry and in situ surface enhanced Raman spectroscopy (SERS). This Pt-modified gold electrode surface assists in oxidizing formic acid at potentials as low as 0.0 V vs. Ag/AgCl which is 0.15 V more negative than a bare Pt surface. The oxidation current obtained on the Pt-modified gold electrode is 72 times higher than on a bare Au surface and 5 times higher than on a bare Pt surface at the same potential. In situ SERS has revealed the involvement of formate at a low frequency as the primary intermediate in this electrooxidation process. While previous studies mainly focused on the formate mode at ca. 1322 cm(-1), it is the first time that a formate peak at ca. 300 cm(-1) was observed on a Pt or Pt-associated surface. A unique relationship has been observed between the formic acid oxidation currents and the SERS intensity of this formate adsorbate. Furthermore, the characteristic Stark effect of the formate proves the strong interaction between the adsorbate and the catalyst. Both electrochemical and spectroscopic results suggest that the formic acid electrooxidation takes place by the dehydrogenation pathway involving a low frequency formate intermediate on the Pt-modified gold electrode catalyst.

  3. Mineralogical and Spectroscopic Characterization of Some Products Resulting from the Weathering Process on the Tomb of Nakht-Djehuty (TT189, Western Thebes, Upper Egypt

    Directory of Open Access Journals (Sweden)

    Hussein Hassan M.H. Mahmoud

    2010-12-01

    Full Text Available The present study deals with the mineralogical and spectroscopic characterization of some weathering products formed on the  decorated surfaces of the tomb of Nakht-Djehuty (TT189, during the time of Ramesses II (the 19th Dynasty, c.1279-1213 BC, western Thebes, Upper Egypt. The wall paintings in the ancient tombs of western Thebes are subjected to salt weathering as a result of the geological structure of the Theban formation and the environmental conditions of the region which enhance the formation of several forms of damage. The weathering forms observed are mainly flakes, salt efflorescence, biofilms and hard crusts. Damaged layers have been collected and investigated using scanning electron microscopy equipped with energy dispersive X-ray analysis system (SEM-EDS, Powder X-ray diffraction analysis (PXRD and Fourier transform spectroscopy (FTIR. The results showed that the main dominant salts affecting the site are sodium chloride (halite, NaCl and phases of sulphates [gypsum, CaSO4 · 2H2O; bassanite, CaSO4 · 0.5H2O and anhydrite, CaSO4] were also detected. FTIR spectra collected on a KBr pellet of thin dark layers covering the decorated surfaces indicated the detection of calcium oxalate probably derived from biodegradation of the organic binders in tempera techniques or the organic coatings used in old restorations of the murals.

  4. FT-IR Spectroscopic characterization of the intermediates in the selective catalytic reduction of NO with methane on Pd/ZrO(formula)-WO(formula) catalyst

    OpenAIRE

    Çayırtepe, İlknur

    2004-01-01

    Cataloged from PDF version of article. This work involves in situ FT-IR spectroscopic study of the routes of formation, composition and thermal stability of strongly bound NOx complexes on the surface of Pd/tungstated zirconia, and transformation of the surface NOx complexes in the presence of methane in order to elucidate the mechanism of selective catalytic reduction of NO with methane. Sol-gel polymer-template synthesis was chosen to obtain high surface area in the prepar...

  5. Characterization and robust filtering of multifunctional surfaces using ISO standards

    Science.gov (United States)

    Friis, K. S.; Godi, A.; De Chiffre, L.

    2011-12-01

    Engineered surfaces containing lubrication pockets and directional surface texture can decrease wear and friction in sliding or rolling contacts. A new generation of multifunctional (MUFU) surfaces has been created by hard machining followed by robot-assisted polishing. The production method allows for a large degree of freedom in specifying surface topography defined by frequency, depth and volume of the lubricant retention valleys, as well as the amount of load bearing area and the surface roughness. The surfaces cannot readily be characterized by means of conventional roughness parameters due to the multi-process production method involved. A series of MUFU surfaces were characterized by using the ISO 13565 standard for stratified surfaces and it is shown that the standard in some cases is inadequate for the characterization of a MUFU surface. To improve the filtering of MUFU surfaces, the robust Gaussian regression filtering technique described in ISO 16610-31 is analyzed and discussed. By slight modifications it is shown how the robust Gaussian regression filter can be applied to remove the form and find a suitable reference surface for further characterization of the MUFU surfaces—even for surfaces with a moderate to small plateau region.

  6. Spectroscopic ellipsometry of SrTiO{sub 3} crystals applied to antiferrodistortive surface phase transition

    Energy Technology Data Exchange (ETDEWEB)

    Dejneka, Alexandr; Jastrabik, Lubomir [Institute of Physics ASCR, Na Slovance 2, 18221 Prague (Czech Republic); Trepakov, Vladimir [Institute of Physics ASCR, Na Slovance 2, 18221 Prague (Czech Republic); Ioffe Physiclal-Technical Institute RAS, 194 021 St-Petersburg (Russian Federation)

    2010-08-15

    This work is devoted to the ellipsometric study of antiferrodistortive (AFD) O{sub h}{sup 1}{yields} D{sub 4h}{sup 18} cubic-to-tetragonal phase transition (PT) of SrTiO{sub 3} surface. Strong influence of surface defect structure on magnitude and temperature evolutions of surface refractive index related to PT was found and investigated. It is shown that even small surface imperfections result in enhancement and strong changes of the surface refractive index when approaching the temperature of PT. This effect is caused by emergence and evolutions in the surface of the structural changes corresponding to order parameter at the temperatures sufficiently higher than transition temperature in the bulk. In the case of structurally perfect crystal surface, the features of the temperature dependence of surface refractive index appeared to be very small and visible at the temperatures a little smaller than transition temperature for bulk that agrees well with predictions of Kaganov-Omel'yanchuk theory. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  7. Spectroscopic and Chromatographic Characterization of Wastewater Organic Matter from a Biological Treatment Plant

    Directory of Open Access Journals (Sweden)

    Min-Hye Park

    2009-12-01

    Full Text Available Spectroscopic and chromatographic changes in dissolved organic matter (DOM characteristics of influent and treated sewage were investigated for a wastewater treatment plant (WWTP with a biological advanced process. Refractory DOM (R-DOM was defined as the dissolved organic carbon concentrations of the samples after 28-day incubation for this study. Specific UV absorbance (SUVA, hydrophobicity, synchronous fluorescence spectra and molecular weight (MW distributions were selected as DOM characteristics. The percent distribution of R-DOM for the effluent was much higher than that of the influent, indicating that biodegradable DOM was selectively removed during the process. Comparison of the influent versus the effluent sewage revealed that SUVA, fulvic-like fluorescence (FLF, humic-like fluorescence (HLF, the apparent MW values were enhanced during the treatment. This suggests that more aromatic and humic-like compounds were enriched during the biological process. No significant difference in the DOM characteristics was observed between the original effluent (i.e., prior to the incubation and the influent sewage after the incubation. This result suggests that the major changes in wastewater DOM characteristics occurring during the biological advanced process were similar to those for simple microbial incubation.

  8. Spectroscopic characterization of Yb:Sc2O3 transparent ceramics

    Institute of Scientific and Technical Information of China (English)

    Lu Shen-Zhou; Yang Qiu-Hong

    2012-01-01

    Yb:Sc2O3 transparent ceramics are fabricated by a conventional ceramic process and sintering in H2 atmosphere.The room-temperature spectroscopic properties are investigated,and the Raman spectrum shows an obvious vibration characteristic band centred at 415 cm-1. There are three broad absorption bands around 891,937,and 971 nm,respectively.The strongest emission peak is centred at 1.04 μm with a broad bandwidth (11 nm) and an emission cross-section of 1.8× 10-20 cm2.The gain coefficient implies a possible laser ability in a range from 990 nm to 1425 nm.The energy-level structure shows that Yb:Sc2O3 ceramics have large Stark splitting at the ground state level due to their strong crystal field.All the results show that Yb:Sc2Oa transparent ceramics are a promising material for short pulse lasers.

  9. Infrared spectroscopic and laser characterization of Tm in disordered double tungstates

    Energy Technology Data Exchange (ETDEWEB)

    Cano-Torres, J.M.; Han, X.; Garcia-Cortes, A.; Serrano, M.D. [Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Cientificas, c/ Sor Juana Ines de la Cruz 3, E-28049 Madrid (Spain); Zaldo, C. [Instituto de Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Cientificas, c/ Sor Juana Ines de la Cruz 3, E-28049 Madrid (Spain)], E-mail: cezaldo@icmm.csic.es; Valle, F.J. [Instituto de Ceramica y Vidrio, Consejo Superior de Investigaciones Cientificas, c/Kelsen 5, E-28049 Madrid (Spain); Mateos, X.; Rivier, S.; Griebner, U.; Petrov, V. [Max-Born-Institute for Nonlinear Optics and Ultrafast Spectroscopy, 2A Max-Born-Street, D-12489 Berlin (Germany)

    2008-01-15

    The relative energy and characteristics of the Tm{sup 3+} levels in tetragonal double tungstate (DT) and double molybdate (DMo) crystals are investigated by low temperature optical spectroscopy with special emphasis on NaLa(WO{sub 4}){sub 2}. In this host the transition bandwidths are intermediate between those found in ordered monoclinic DT and in other disordered tetragonal DT and DMo crystals. This allows for better band resolution of the S{sub 4} site symmetry features in the disordered scheelite-like structure. The potential of such Tm-doped crystals for building infrared tunable lasers is discussed on the basis of the calculated cross sections and their comparison with the experimental photoluminescence. Information on the crystal growth and Tm{sup 3+} spectroscopic details are provided. Tm:NaLa(WO{sub 4}){sub 2} laser operation with the available sample is more efficient for {sigma}-polarized configuration. Up to 200 mW of output power was obtained at {lambda} = 1888 nm and laser tunability extends from 1789 to 1950 nm.

  10. Structural Modifications of Deoxycholic Acid to Obtain Three Known Brassinosteroid Analogues and Full NMR Spectroscopic Characterization.

    Science.gov (United States)

    Herrera, Heidy; Carvajal, Rodrigo; Olea, Andrés F; Espinoza, Luis

    2016-08-27

    An improved synthesis route for obtaining known brassinosteroid analogues, i.e., methyl 2α,3α-dihydroxy-6-oxo-5α-cholan-24-oate (11), methyl 3α-hydroxy-6-oxo-7-oxa-5α-cholan-24-oate (15) and methyl 3α-hydroxy-6-oxa-7-oxo-5α-cholan-24-oate (16), from hyodeoxycholic acid (4) maintaining the native side chain is described. In the alternative procedure, the di-oxidized product 6, obtained in the oxidation of methyl hyodeoxycholate 5, was converted almost quantitatively into the target monoketone 7 by stereoselective reduction with NaBH₄, increasing the overall yield of this synthetic route to 96.8%. The complete ¹H- and (13)C-NMR assignments for all compounds synthesized in this work have been made by 1D and 2D heteronuclear correlation gs-HSQC and gs-HMBC techniques. Thus, it was possible to update the spectroscopic information of ¹H-NMR and to accomplish a complete assignment of all (13)C-NMR signals for analogues 5-16, which were previously reported only in partial form.

  11. Characterization of the binding of nevadensin to bovine serum albumin by optical spectroscopic technique

    Science.gov (United States)

    Yu, Zhaolian; Li, Daojin; Ji, Baoming; Chen, Jianjun

    2008-10-01

    Binding of nevadensin to bovine serum albumin (BSA) has been studied in detail at 298 and 310 K using spectrophotometric technique. The intrinsic fluorescence of BSA was strongly quenched by the addition of nevadensin and spectroscopic observations are mainly rationalized in terms of a static quenching process at lower concentration of nevadensin ( Cdrug/ CBSA drug/ CBSA > 1). The binding parameters for the reaction at a pH above (7.40) or below (3.40) the isoelectric point have been calculated according to the double logarithm regression curve. The thermodynamic parameters Δ H0, Δ G0, Δ S0 at different temperatures and binding mechanism of nevadensin to BSA at pH 7.40 and 3.40 were evaluated. The binding ability of nevadensin to BSA at pH 7.40 was stronger than that at pH 3.40. Steady fluorescence, synchronous fluorescence and circular dichroism (CD) were applied to investigate protein conformation. A value of 2.15 nm for the average distance r between nevadensin (acceptor) and tryptophan residues (Trp) of BSA (donor) was derived from the fluorescence resonance energy transfer. Moreover, influence of pH on the interaction nevadensin with BSA was investigated.

  12. Synthesis, spectroscopic characterization and electrochemical studies of Girard's T chromone complexes

    Science.gov (United States)

    Al-Saeedi, Sameerah I.; Alaghaz, Abdel-Nasser M. A.; Ammar, Reda A.

    2016-05-01

    Complexes of cobalt(II), nickel(II), copper(II) and zinc(II) of general composition [M(L)2] have been. The elemental analyses, molar conductance, spectral, magnetic moment and thermal measurements studies of the compounds led to the conclusion that the ligand acts as a tridentate manner (OON). The molar conductance of the metal complexes in fresh solution of DMSO lies in the range of 8.10-10.18 Ω-1 cm2 mol-1 indicating their non-electrolytic behavior. On the basis of analytical and spectroscopic techniques, octahedral geometry of the complexes was proposed. The ligand field parameters were calculated for Co(II), Ni(II) and Cu(II) complexes and their values were found in the range reported for a octahedral structure. The data show that the complexes have composition of ML2 type. The activation of thermodynamic parameters are calculated using different equations. The octahedral geometry of the complexes is confirmed using DFT method from DMOL3 calculations and ligand field parameters. The cyclic voltammograms of the Cu(II)/Co(II)/Ni(II) complexes investigated in DMSO solution exhibit metal centered electroactivity in the potential range -1.5 to +1.5 V. The electrochemical data obtained for Cu(II) complexes explains the change of structural arrangement of the ligand around Cu(II) ions.

  13. Spectroscopic exploration and thermodynamic characterization of desvenlafaxine interacting with fluorescent bovine serum albumin.

    Science.gov (United States)

    Patgar, Manjanath; Durgannavar, Amar; Nandibewoor, Sharanappa; Chimatadar, Shivamurti

    2017-02-01

    The mechanism of the interaction between bovine serum albumin (BSA) and desvenlafaxine was studied using fluorescence, ultraviolet absorption, 3-dimensional fluorescence spectroscopy, circular dichroism, synchronous fluorescence spectroscopy, cyclic voltametry, differential scanning calorimetry, and attenuated total reflection-Fourier transform infrared spectroscopic techniques under physiological condition at pH 7.4. Stern-Volmer calculations authenticate the fluorescence of BSA that was quenched by desvenlafaxine in a collision quenching mode. The fluorescence quenching method was used to evaluate number of binding sites "n" and binding constant KA that were measured, and various thermodynamic parameters were evaluated at different temperatures by using the van't Hoff equation and differential scanning calorimetry technique, which indicated a spontaneous and hydrophobic interaction between BSA and desvenlafaxine. According to the Förster theory we calculate the distance between the donor, BSA and acceptor, desvenlafaxine molecules. Furthermore, circular dichroism and attenuated total reflection-Fourier transform infrared spectroscopy indicate nominal changes in the secondary structure of the protein.

  14. SEM, EDX, infrared and Raman spectroscopic characterization of the silicate mineral yuksporite.

    Science.gov (United States)

    Frost, Ray L; López, Andrés; Scholz, Ricardo; Theiss, Frederick L; Romano, Antônio Wilson

    2015-02-25

    The mineral yuksporite (K,Ba)NaCa2(Si,Ti)4O11(F,OH)⋅H2O has been studied using the combination of SEM with EDX and vibrational spectroscopic techniques of Raman and infrared spectroscopy. Scanning electron microscopy shows a single pure phase with cleavage fragment up to 1.0 mm. Chemical analysis gave Si, Al, K, Na and Ti as the as major elements with small amounts of Mn, Ca, Fe and REE. Raman bands are observed at 808, 871, 930, 954, 980 and 1087 cm(-1) and are typical bands for a natural zeolite. Intense Raman bands are observed at 514, 643 and 668 cm(-1). A very sharp band is observed at 3668 cm(-1) and is attributed to the OH stretching vibration of OH units associated with Si and Ti. Raman bands resolved at 3298, 3460, 3562 and 3628 cm(-1) are assigned to water stretching vibrations. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Minerals from Macedonia XXIII. Spectroscopic and structural characterization of schorl and beryl cyclosilicates.

    Science.gov (United States)

    Makreski, Petre; Jovanovski, Gligor

    2009-08-01

    IR and Raman spectroscopy study on two collected cyclosilicate species: schorl (from tourmaline group), Na(Fe,Mg)(3)Al(6)(BO(3))(3)Si(6)O(18)(OH,F)(4) and beryl (Be,Mg,Fe)(3)Al(2)Si(6)O(18) were carried out. Although beryl is nominally anhydrous mineral, vibrational results strongly indicate that H(2)O molecules exist in the structural channels. The number of vibrational bands and their frequencies revealed the presence of H(2)O type II, in which C(2) symmetry axis of the water molecule is parallel to the structural channel (and to the c-axis of beryl). On the other hand, it was found that observed bands in the IR and Raman OH stretching region of the other tourmaline varieties appear as a result of the cation combinations involving dominant presence of Mg and Fe cations in the Y structural sites. The strong indication derived from the vibrational spectroscopic results that the studied mineral represents a schorl variety, coincide very well with the results obtained by powder X-ray diffraction and X-ray microprobe analysis. Both minerals show IR spectral similarities in the region below 1500 cm(-1), whereas the resemblance between the Raman spectra (1500-100 cm(-1)) is less expressed confirming that these spectra are more sensitive to compositional changes and to structural disorder. The identification of both minerals was additionally supported by studying the powder X-ray diffraction diagrams.

  16. Electroanalytical and spectroscopic characterization of poly(o-phenylenediamine) grown on highly oriented pyrolytic graphite.

    Science.gov (United States)

    De Giglio, Elvira; Losito, Ilario; Torsi, Luisa; Sabbatini, Luigia; Zambonin, Pier Giorgio

    2003-03-01

    The polymerization of ortho-phenylenediamine (o-PD) on Highly Oriented Pyrolytic Graphite (HOPG) at different pH (1,3,5,7) was investigated by electroanalytical and spectroscopic methods. Cyclic voltammetry was used both to polymerize o-PD and to study the electroactivity of the resulting poly(ortho-phenylenediamine) (PPD) film. A redox couple associated to the PPD electroactivity, deeply influenced by the pH adopted during polymerization, was recorded. A correlation between this feature and the electrochemistry shown by the oligomers of o-PD, generated in solution during the polymer synthesis, was also found. A comparison between the absorption spectra, in the visible region, of the soluble oligomers and of the PPD films was also performed, suggesting that changes in both the polymer and the oligomer structure occur and are highly related to the polymerization pH. In particular, a higher degree of conjugation is exhibited by the PPD films electrosynthesised at lower pH and this likely explains the higher conductivity as well as the higher electroactivity shown by the material obtained in these conditions.

  17. Synthesis, crystal structure, spectroscopic characterization and optical properties of bis(4-acetylanilinium) tetrachlorocobalt (II)

    Science.gov (United States)

    Abkari, A.; Chaabane, I.; Guidara, K.

    2017-02-01

    The chemical preparation, crystal structure, spectroscopic investigations and optical features are given for a novel organic-inorganic hybrid material [C8H10NO]2CoCl4.The compound is crystallized in the orthorhombic space group Cmca, with the following unit cell parameters: a=19.461(2) Å, b=15.523(2) Å, c=13.7436(15) Å, and Z=8. The atomic arrangement shows an alternation of organic and inorganic layers along the b-axis. The cohesion between these entities is performed by N-H…Cl and N-H…O hydrogen bonds and π-π stacking interactions. Infrared and Raman spectra at room temperature are recorded in the 4000-400 and 4000-0 cm-1 frequency regions, respectively and analyzed on the basis of literature data. This study confirms the presence of the organic cation [C8H10NO]+ and of the [CoCl4]2- anion. UV-vis spectroscopy results showed the indirect transition with band gap energy 2.98 eV.

  18. Multi-spectroscopic characterization of bovine serum albumin upon interaction with atomoxetine

    Directory of Open Access Journals (Sweden)

    Arunkumar T. Buddanavar

    2017-06-01

    Full Text Available The quenching interaction of atomoxetine (ATX with bovine serum albumin (BSA was studied in vitro under optimal physiological condition (pH=7.4 by multi-spectroscopic techniques. The mechanism of ATX-BSA system was a dynamic quenching process and was confirmed by the fluorescence spectra and lifetime measurements. The number of binding sites, binding constants and other binding characteristics were computed. Thermodynamic parameters ∆H° and ∆S° indicated that intermolecular hydrophobic forces predominantly stabilized the drug-protein system. The average binding distance between BSA and ATX was studied by Försters theory. UV-absorption, Fourier transform infrared spectroscopy (FT-IR, circular dichroism (CD, synchronous spectra and three-dimensional (3D fluorescence spectral results revealed the changes in micro-environment of secondary structure of protein upon the interaction with ATX. Displacement of site probes and the effects of some common metal ions on the binding of ATX with BSA interaction were also studied.

  19. Spectroscopic characterization of HD 95086 b with the Gemini Planet Imager

    CERN Document Server

    De Rosa, Robert J; Patience, Jenny; Graham, James R; Doyon, René; Lafrenière, David; Macintosh, Bruce; Pueyo, Laurent; Rajan, Abhijith; Wang, Jason J; Ward-Duong, Kimberly; Hung, Li-Wei; Maire, Jérôme; Nielsen, Eric L; Ammons, S Mark; Bulger, Joanna; Cardwell, Andrew; Chilcote, Jeffrey K; Galvez, Ramon L; Gerard, Benjamin L; Goodsell, Stephen; Hartung, Markus; Hibon, Pascale; Ingraham, Patrick; Johnson-Groh, Mara; Kalas, Paul; Konopacky, Quinn M; Marchis, Franck; Marois, Christian; Metchev, Stanimir; Morzinski, Katie M; Oppenheimer, Rebecca; Perrin, Marshall D; Rantakyrö, Fredrik T; Savransky, Dmitry; Thomas, Sandrine

    2016-01-01

    We present new $H$ (1.5-1.8 $\\mu$m) photometric and $K_1$ (1.9-2.2 $\\mu$m) spectroscopic observations of the young exoplanet HD 95086 b obtained with the Gemini Planet Imager. The $H$-band magnitude has been significantly improved relative to previous measurements, whereas the low resolution $K_1$ ($\\lambda/\\delta\\lambda \\approx 66$) spectrum is featureless within the measurement uncertainties, and presents a monotonically increasing pseudo-continuum consistent with a cloudy atmosphere. By combining these new measurements with literature $L^{\\prime}$ photometry, we compare the spectral energy distribution of the planet to other young planetary-mass companions, field brown dwarfs, and to the predictions of grids of model atmospheres. HD 95086 b is over a magnitude redder in $K_1-L^{\\prime}$ color than 2MASS J12073346-3932539 b and HR 8799 c and d, despite having a similar $L^{\\prime}$ magnitude. Considering only the near-infrared measurements, HD 95086 b is most analogous to the brown dwarfs 2MASS J2244316+204...

  20. Thermomorphic phase separation in ionic liquid-organic liquid systems - conductivity and spectroscopic characterization

    DEFF Research Database (Denmark)

    Riisager, Anders; Fehrmann, Rasmus; Berg, Rolf W.

    2005-01-01

    Electrical conductivity, FT-Raman and NMR measurements are demonstrated as useful tools to probe and determine phase behavior of thermomorphic ionic liquid-organic liquid systems. To illustrate the methods, consecutive conductivity measurements of a thermomorphic methoxyethoxyethyl-imidazolium io...... of the components in the system, the liquid-liquid equilibrium phase diagram of the binary mixture, and signify the importance of hydrogen bonding between the ionic liquid and the hydroxyl group of the alcohol.......Electrical conductivity, FT-Raman and NMR measurements are demonstrated as useful tools to probe and determine phase behavior of thermomorphic ionic liquid-organic liquid systems. To illustrate the methods, consecutive conductivity measurements of a thermomorphic methoxyethoxyethyl......-imidazolium ionic liquid/1-hexanol system are performed in the temperature interval 25-80 degrees C using a specially constructed double-electrode cell. In addition, FT-Raman and H-1-NMR spectroscopic studies performed on the phase-separable system in the same temperature interval confirm the mutual solubility...

  1. Spectroscopic and functional characterization of Lampyris turkestanicus Iuciferase: a comparative study

    Institute of Scientific and Technical Information of China (English)

    Mojtaba Mortazavi; Saman Hosseinkhani; Khosro Khajeh; Bijan Ranjbar; A.Rahman Emamzadeh

    2008-01-01

    Functional expression and spectroscopic analysis of luciferases from Lampyris turkestanicus and Photinus pyralis were carried out. cDNA encoding L. turkestanicus luciferase was isolated by reverse transcription-polymerase chain reaction, cloned, and functionally expressed in Escherichia coil. The luciferases were purified to homogeneity using Ni-nitrilotriacetic acid Sepharose, and kinetic properties of luciferase from L. turkestanicus were compared with that from P.pyralis. Amino acid differences in its primary structures in relation to P.pyralis luciferase brought about changes in the kinetic properties of the enzyme as evidenced by substantial lowering of Km for ATP, increased light decay time, and decreased thermostability. Luciferase from L.turkestanicus was used to carry out Michaelis-Menten kinetics with a Km of 95.5 μM for A TP and 20 μM for inciferin.Maximum activity was recorded at pH 8.5, so it might be a suitable reporter for microbial screening at alkaline pH.Tryptophan fluorescence for P.pyralis luciferase was higher than L. turkestanicus luciferase. Substitution of some residues in L. turkestanicus hiciferase appears to change the kinetic properties by inducing a substantial tertiary structural change, without a large effect on secondary structural elements, as revealed by intrinsic and extrinsic fluorescence, Fourier transform infrared spectroscopy, and near-ultraviolet circular dichroism spectra.

  2. Viscoelastic, Spectroscopic, and Microscopic Characterization of Novel Bio-Based Plasticized Poly(vinyl chloride Compound

    Directory of Open Access Journals (Sweden)

    Mei Chan Sin

    2014-01-01

    Full Text Available Plasticized poly(vinyl chloride (PVC is one of the most widely consumed commodity plastics. Nevertheless, the commonly used plasticizers, particularly phthalates, are found to be detrimental to the environment and human health. This study aimed to investigate the ability of an alternative greener material, medium-chain-length polyhydroxyalkanoates (mcl-PHA, a kind of biopolyester and its thermally degraded oligoesters, to act as a compatible bioplasticizer for PVC. In this study, mcl-PHA were synthesized by Pseudomonas putida PGA1 in shake flask fermentation using saponified palm kernel oil (SPKO and subsequently moderately thermodegraded to low molecular weight oligoesters (degPHA. SEM, ATR-FTIR, 1H-NMR, and DMA were conducted to study the film morphology, microstructure, miscibility, and viscoelastic properties of the PVC-PHA and PVC/degPHA binary blends. Increased height and sharpness of tan δmax⁡ peak for all binary blends reveal an increase in chain mobility in the PVC matrix and high miscibility within the system. The PVC-PHA miscibility is possibly due to the presence of specific interactions between chlorines of PVC with the C=O group of PHA as evidenced by spectroscopic analyses. Dynamic viscoelastic measurements also showed that mcl-PHA and their oligoesters could reduce the Tg of PVC, imparting elasticity to the PVC compounds and decreasing the stiffness of PVC.

  3. A spectroscopic experimental and computer-assisted empirical model for the production and energetics of excited oxygen molecules formed by atom recombination on shuttle tile surfaces

    Science.gov (United States)

    Owan, D. A.

    1981-01-01

    A visible emission spectroscopic method was developed. The amounts of excited singlet and triplet oxygen molecules produced by recombination on the Space Shuttle Orbiter thermal protective tiles at elevated temperatures are determined. Rate constants and energetics of the extremely exothermic reaction are evaluated in terms of a chemical and mathematical model. Implications for potential contribution to Shuttle surface reentry heating fluxes are outlined.

  4. Topographic characterization of nanostructures on curved polymer surfaces

    DEFF Research Database (Denmark)

    Feidenhans'l, Nikolaj Agentoft; Petersen, Jan C.; Taboryski, Rafael J.

    2014-01-01

    The availability of portable instrumentation for characterizing surface topography on the micro- and nanometer scale is very limited. Particular the handling of curved surfaces, both concave and convex, is complicated or not possible on current instrumentation. However, the currently growing use ...... surfaces in vibration prone production facilities has not previously been reported in the literature, and therefore has great novelty potential....... that the instrument can characterize and validate the micro- and nanoscale topography directly in the production facility, as the interruptive time delay induced from shipping to an external facility is not compatible with present large-scale production routines. Satisfactory characterization of nanostructured curved...

  5. Nanoscale characterization of surfaces and interfaces

    CERN Document Server

    DiNardo, N John

    2008-01-01

    Derived from the highly acclaimed series Materials Science and Technology, this book provides in-depth coverage of STM, AFM, and related non-contact nanoscale probes along with detailed applications, such as the manipulation of atoms and clusters on a nanometer scale. The methods are described in terms of the physics and the technology of the methods and many high-quality images demonstrate the power of these techniques in the investigation of surfaces and the processes which occur on them.Topics include:Semiconductor Surfaces and Interfaces * Insulators * Layered Compounds * Charg

  6. Influence Factors of Fractal Characterization of Reciprocating Sliding Wear Surfaces

    Institute of Scientific and Technical Information of China (English)

    周新聪; 冯伟; 严新平; 萧汉梁

    2004-01-01

    The principal purpose of this paper is to investigate influence factors of fractal characterization of reciprocating sliding wear surfaces.The wear testing was completed to simulate the real running condition of the diesel engine 8NVD48A-2U.The test results of wear surface morphology dimension characterization show that wear surface profiles have statistical self-affine fractal characteristics.In general, there are no effects of the profilometer sampling spacing and sampling length and evaluation length on the fractal dimensions of the surfaces.However, if the evaluation length is too short, the structure function logarithm of the surface profile is scattered.The sampling length acting as a filter is an important part of the fractal dimension measurement.If the sampling length is too short, the evaluation of the fractal dimension will have a larger standard deviation.The continuous wavelet transform can be used to improve surface profile dimension characterization.

  7. Spectroscopic detection of atom-surface interactions in an atomic vapour layer with nanoscale thickness

    CERN Document Server

    Whittaker, K A; Hughes, I G; Sargsyan, A; Sarkisyan, D; Adams, C S

    2015-01-01

    We measure the resonance line shape of atomic vapor layers with nanoscale thickness confined between two sapphire windows. The measurement is performed by scanning a probe laser through resonance and collecting the scattered light. The line shape is dominated by the effects of Dicke narrowing, self-broadening, and atom-surface interactions. By fitting the measured line shape to a simple model we discuss the possibility to extract information about the atom-surface interaction.

  8. Characterization of multifunctional surfaces during fabrication

    DEFF Research Database (Denmark)

    Godi, Alessandro; Friis, Kasper Storgaard; De Chiffre, Leonardo

    2011-01-01

    The multifunctional surfaces herein studied are intended for carrying high loads as well as providing lubrication. They are produced by hard turning, creating a periodic pattern that will constitute the lubricant channels, followed by accurate Robot Assisted Polishing to smooth the tops...

  9. Synthesis, spectroscopic characterization, crystallographic studies and antibacterial assays of new copper(II) complexes with sulfathiazole and nimesulide

    Science.gov (United States)

    Nunes, Julia Helena Bormio; de Paiva, Raphael Enoque Ferraz; Cuin, Alexandre; da Costa Ferreira, Ana Maria; Lustri, Wilton Rogério; Corbi, Pedro Paulo

    2016-05-01

    New ternary copper(II) complexes of sulfathiazole (SFT, C9H8N3O2S2) or nimesulide (NMS, C13H11N2O5S) and 2,2‧-bipyridine (bipy) were synthesized, and characterized by chemical and spectroscopic techniques. Elemental analyses indicated a 2:1:1 sulfonamide/copper/bipy composition for both complexes. Mass spectrometric measurements permitted identifying the molecular ions [Cu(SFT)2(bipy)+H]+ and [Cu(NMS)2(bipy)+H]+ at m/z 728 and 835, respectively, confirming the proposed compositions. Crystal structure of the [Cu(SFT)2(bipy)] complex was solved by powder X-ray diffraction analysis (PXRD), attesting that the Cu(II) ion is hexacoordinated in a distorted octahedral geometry. Each SFT molecule coordinates to the metal ion by the nitrogen atoms of the SO2-N group and of the heterocyclic ring. The coordination sphere is completed by a bipyridine. Electronic paramagnetic resonance (EPR) studies were carried out for the [Cu(NMS)2(bipy)] complex, indicating a tetragonal environment around the metal ion. It was suggested that NMS coordinates to Cu(II) by the nitrogen and oxygen atoms of the SO2-N group, which was confirmed by infrared spectroscopic studies. Biological studies showed the antibacterial activity of both Cu-SFT and Cu-NMS complexes, with the minimum inhibitory concentration (MIC) values ranging from 0.10 to 0.84 mmol L-1 against Gram-negative bacteria for [Cu(SFT)2(bipy)], and from 1.50 to 3.00 mmol L-1 against Gram-positive and -negative bacteria for [Cu(NMS)2(bipy)].

  10. X-Ray Photoelectron Spectroscopic Characterization of Chemically Modified Electrodes Used as Chemical Sensors and Biosensors: A Review

    Directory of Open Access Journals (Sweden)

    Elio Desimoni

    2015-04-01

    Full Text Available The characterization of chemically modified sensors and biosensors is commonly performed by cyclic voltammetry and electron microscopies, which allow verifying electrode mechanisms and surface morphologies. Among other techniques, X-ray photoelectron spectroscopy (XPS plays a unique role in giving access to qualitative, quantitative/semi-quantitative and speciation information concerning the sensor surface. Nevertheless, XPS remains rather underused in this field. The aim of this paper is to review selected articles which evidence the useful performances of XPS in characterizing the top surface layers of chemically modified sensors and biosensors. A concise introduction to X-ray Photoelectron Spectroscopy gives to the reader the essential background. The application of XPS for characterizing sensors suitable for food and environmental analysis is highlighted.

  11. Fractal characterization of surface electrical discharges

    Energy Technology Data Exchange (ETDEWEB)

    Egiziano, L.; Femia, N.; Lupo' , G.; Tucci, V. (Salerno Univ. (Italy). Ist. di Ingegneria Elettronica Naples Univ. (Italy). Dip. di Ingegneria Elettrica)

    1991-01-01

    The concepts of fractal geometry have been usefully applied to describe several physical processes whose growth mechanisms are characterized by complex topological structures. The fractal characterization of electrical discharges taking place at the air/solid dielectric interface is considered in this paper. A numerical procedure allowing the reproduction the typical discharge patterns, known as Lichtenberg figures, is presented: the growth process of the discharge is simulated by solving iteratively the Laplace equation with moving boundary conditions and by considering two power probability laws whose exponents determine the ramification level of the structure. The discharge patterns are then considered as fractal sets and their characteristic parameters are determined. The dependence of the typical structures on the two exponents of the probability laws are also discussed.

  12. Spectroscopic and nonlinear photophysical characterization of organic octupolar-compounds supported by anodic-alumina nanotube-arrays

    Energy Technology Data Exchange (ETDEWEB)

    Morales-Saavedra, O.G., E-mail: omar.morales@ccadet.unam.mx [Lab. of Nonlinear Optics, Centro de Ciencias Aplicadas y Desarrollo Tecnologico, Universidad Nacional Autonoma de Mexico, CCADET-UNAM Cd. Universitaria, Coyoacan, A.P. 70-186, C.P. 04510 Mexico City (Mexico); Ontiveros-Barrera, F.G. [Lab. of Nonlinear Optics, Centro de Ciencias Aplicadas y Desarrollo Tecnologico, Universidad Nacional Autonoma de Mexico, CCADET-UNAM Cd. Universitaria, Coyoacan, A.P. 70-186, C.P. 04510 Mexico City (Mexico); Hennrich, G. [Departamento de Quimica Organica, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Mata-Zamora, M.E.; Rodriguez-Rosales, A.A.; Banuelos, J.G. [Lab. of Nonlinear Optics, Centro de Ciencias Aplicadas y Desarrollo Tecnologico, Universidad Nacional Autonoma de Mexico, CCADET-UNAM Cd. Universitaria, Coyoacan, A.P. 70-186, C.P. 04510 Mexico City (Mexico)

    2011-11-15

    Highlights: > Preparation of organic-inorganic nanostructured hybrid materials. > Insertion of octupolar compounds in alumina nanotube arrays. > Linear and nonlinear photophysical characterization of solid-state hybrid structures. > Fabrication of photonic materials. - Abstract: Amorphous anodic alumina membranes (AAM) comprising highly ordered nanometric porous arrays (porous anodic aluminas: PAA) with 1D-nanotube dimensions of {approx}75 nm in diameter and 45 microns in depth were successfully prepared and used as nanostructured host networks for different functionalized octupolar chromophores (named here Oct-(n)). Atomic force microscopy (AFM) studies performed on the developed hybrid systems confirmed a homogeneous insertion of these organic molecules into the PAA nanotube-arrays. Samples with high structural quality were selected for several photophysical characterizations: Comprehensive X-ray diffraction (XRD) and optical spectroscopic characterizations performed according to UV-vis absorption, photoluminescent (PL) and Raman measurements revealed the structural and optical performance of these molecules within the PAA-confinement. Since the implemented optical chromophores were specifically functionalized for nonlinear optical (NLO) applications, the obtained Oct-(n)/PAA-based amorphous hybrids were also characterized according to cubic NLO-techniques such as third harmonic generation (THG) and the Z-Scan method. PAA-confined octupolar chromophores have shown interesting linear and NLO optical properties which have not yet been intensively investigated in bulk hybrid systems; hence, the obtained hybrid nanostructures represent a promising field of investigation in the route to functional octupolar-based materials, where different self-assembled molecular structures may be formed, giving rise to enhanced linear and NLO-properties.

  13. Hafnium(IV) chloride complexes with chelating β-ketiminate ligands: Synthesis, spectroscopic characterization and volatility study.

    Science.gov (United States)

    Patil, Siddappa A; Medina, Phillip A; Antic, Aleks; Ziller, Joseph W; Vohs, Jason K; Fahlman, Bradley D

    2015-09-05

    The synthesis and characterization of four new β-ketiminate hafnium(IV) chloride complexes dichloro-bis[4-(phenylamido)pent-3-en-2-one]-hafnium (4a), dichloro-bis[4-(4-methylphenylamido)pent-3-en-2-one]-hafnium (4b), dichloro-bis[4-(4-methoxyphenylamido)pent-3-en-2-one]-hafnium (4c), and dichloro-bis[4-(4-chlorophenylamido)pent-3-en-2-one]-hafnium (4d) are reported. All the complexes (4a-d) were characterized by spectroscopic methods ((1)H NMR, (13)C NMR, IR), and elemental analysis while the compound 4c was further examined by single-crystal X-ray diffraction, revealing that the complex is monomer with the hafnium center in octahedral coordination environment and oxygens of the chelating N-O ligands are trans to each other and the chloride ligands are in a cis arrangement. Volatile trends are established for four new β-ketiminate hafnium(IV) chloride complexes (4a-d). Sublimation enthalpies (ΔHsub) were calculated from thermogravimetric analysis (TGA) data, which show that, the dependence of ΔHsub on the molecular weight (4a-c) and inductive effects from chlorine (4d). Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Synthesis, spectroscopic, structural and thermal characterizations of vanadyl(IV) adenine complex prospective as antidiabetic drug agent

    Science.gov (United States)

    El-Megharbel, Samy M.; Hamza, Reham Z.; Refat, Moamen S.

    2015-01-01

    The vanadyl(IV) adenine complex; [VO(Adn)2]ṡSO4; was synthesized and characterized. The molar conductivity of this complex was measured in DMSO solution that showed an electrolyte nature. Spectroscopic investigation of the green solid complex studied here indicate that the adenine acts as a bidentate ligand, coordinated to vanadyl(IV) ions through the nitrogen atoms N7 and nitrogen atom of amino group. Thus, from the results presented the vanadyl(IV) complex has square pyramid geometry. Further characterizations using thermal analyses and scanning electron techniques was useful. The aim of this paper was to introduce a new drug model for the diabetic complications by synthesized a novel mononuclear vanadyl(IV) adenine complex to mimic insulin action and reducing blood sugar level. The antidiabetic ability of this complex was investigated in STZ-induced diabetic mice. The results suggested that VO(IV)/adenine complex has antidiabetic activity, it improved the lipid profile, it improved liver and kidney functions, also it ameliorated insulin hormone and blood glucose levels. The vanadyl(IV) complex possesses an antioxidant activity and this was clear through studying SOD, CAT, MDA, GSH and methionine synthase. The current results support the therapeutic potentiality of vanadyl(IV)/adenine complex for the management and treatment of diabetes.

  15. Characterization of aluminum surfaces: Sorption and etching

    Science.gov (United States)

    Polkinghorne, Jeannette Clera

    Aluminum, due to its low density and low cost, is a key material for future lightweight applications. However, like other structural materials, aluminum is subject to various forms of corrosion damage that annually costs the United States approximately 5% of its GNP [1]. The main goal is to investigate the effects of various solution anions on aluminum surfaces, and specifically probe pit initiation and inhibition. Using surface analysis techniques including X-ray photoelectron spectroscopy, Auger electron spectroscopy, and scanning electron microscopy, results have been correlated with those obtained from electrochemical methods and a radiolabeling technique developed in the Wieckowski laboratory. Analysis of data has indicated that important variables include type of anion, solution pH, and applied electrode potential. While aggressive anions such as chloride are usually studied to elucidate corrosion processes to work ultimately toward inhibition, its corrosive properties can be successfully utilized in the drive for higher energy and smaller-scale storage devices. Fundamental information gained regarding anion interaction with the aluminum surface can be applied to tailor etch processes. Standard electrochemical techniques and SEM are respectively used to etch and analyze the aluminum substrate. Aluminum electrolytic capacitors are comprised of aluminum anode foil covered by an anodically grown aluminum oxide dielectric film, electrolytic paper impregnated with electrolyte, and aluminum cathode foil. Two main processes are involved in the fabrication of aluminum electrolytic capacitors, namely etching and anodic oxide formation. Etching of the anode foil results in a higher surface area (up to 20 times area enlargement compared to unetched foil) that translates into a higher capacitance gain, permitting more compact and lighter capacitor manufacture. Anodic oxide formation on the anode, creates the required dielectric to withstand high voltage operation. A

  16. Morphological and spectroscopic characterization of laser-ablated tungsten at various laser irradiances

    Energy Technology Data Exchange (ETDEWEB)

    Akram, Mahreen; Bashir, Shazia; Hayat, Asma; Mahmood, Khaliq; Dawood, Asadullah [Government College University, Centre for Advanced Studies in Physics, Lahore (Pakistan); Rafique, Muhammad Shahid [University of Engineering and Technology, Department of Physics, Lahore (Pakistan); Bashir, M.F. [COMSATS Institute of Information Technology, Department of Physics, Lahore (Pakistan)

    2015-06-15

    The variation in surface morphology and plasma parameters of laser irradiated tungsten has been investigated as a function of irradiance. For this purpose, Nd:YAG laser (1064 nm, 10 ns, 10 Hz) is employed. Tungsten targets were exposed to various laser irradiances ranging from 6 to 50 GW/cm{sup 2} under ambient environment of argon at a pressure of 20 Torr. Scanning electron microscope analysis has been performed to analyze the surface modification of irradiated tungsten. It revealed the formation of micro- and nanoscale surface structures. In central ablated area, distinct grains and crack formation are observed, whereas peripheral ablated areas are dominated by cones and pinhole formation. It was observed that at irradiances exceeding a value of 13 GW/cm{sup 2}, the morphological trend of the observed structures has been changed from erosion to melting and re-deposition dominant phase. Ablation efficiency as a function of laser irradiance has also been investigated by measuring the crater depth using surface profilometry analysis. It is found to be maximum at an irradiance of 13 GW/cm{sup 2} and decreases at high laser irradiances. In order to correlate the accumulated effects of plasma parameters with the surface modification, laser-induced breakdown spectroscopy analysis has been performed. The electron temperature and number density of tungsten plasma have been evaluated at various laser irradiances. Initially with the increase of the laser irradiance up to 13 GW/cm{sup 2}, an increasing trend is observed for both plasma parameters due to enhanced energy deposition. Afterward, a decreasing trend is achieved which is attributed to the shielding effect. With further increase in irradiance, a saturation stage comes and insignificant changes are observed in plasma parameters. This saturation is explainable on the basis of the formation of a self-regulating regime near the target surface. Surface modifications of laser irradiated tungsten have been correlated with

  17. Characterization of Organosolv Lignins using Thermal and FT-IR Spectroscopic Analysis

    Science.gov (United States)

    Rhea J. Sammons; David P. Harper; Nicole Labbe; Joseph J. Bozell; Thomas Elder; Timothy G. Rials

    2013-01-01

    A group of biomass-derived lignins isolated using organosolv fractionation was characterized by FT-IR spectral and thermal property analysis coupled with multivariate analysis. The principal component analysis indicated that there were significant variations between the hardwood, softwood, and grass lignins due to the differences in syringyl and guaiacyl units as well...

  18. Green preparation and spectroscopic characterization of plasmonic silver nanoparticles using fruits as reducing agents

    DEFF Research Database (Denmark)

    Hyllested, Jes Ærøe; Espina Palanco, Marta; Hagen, Nicolai;

    2015-01-01

    microscopy shows that the shapes of the nanoparticles are different depending on the fruit used for preparation. The green preparation process results mainly in individual nanoparticles with a very poor tendency to form aggregates with narrow gaps even when aggregation is forced by the addition of Na......Cl. This explains only modest enhancement factors for near-infrared-excited surface enhanced Raman scattering. In addition to the surface plasmon band, UV-visible absorption spectra show features in the UV range which indicates also the presence of small silver clusters, such as Ag42+. The increase of the plasmon...... absorption correlates with the decrease of absorption band in the UV. This confirms the evolution of silver nanoparticles from silver clusters. The presence of various silver clusters on the surface of the “green” plasmonic silver nanoparticles is also supported by a strong multi-color luminesce signal...

  19. Green preparation and spectroscopic characterization of plasmonic silver nanoparticles using fruits as reducing agents

    DEFF Research Database (Denmark)

    Hyllested, Jes Ærøe; Espina Palanco, Marta; Hagen, Nicolai

    2015-01-01

    Chemicals typically available in plants have the capability to reduce silver and gold salts and to create silver and gold nanoparticles. We report the preparation of silver nanoparticles with sizes between 10 and 300 nm from silver nitrate using fruit extract collected from pineapples and oranges...... as reducing agents. The evolvement of a characteristic surface plasmon extinction spectrum in the range of 420 nm to 480 nm indicates the formation of silver nanoparticles after mixing silver nitrate solution and fruit extract. Shifts in plasmon peaks over time indicate the growth of nanoparticles. Electron......Cl. This explains only modest enhancement factors for near-infrared-excited surface enhanced Raman scattering. In addition to the surface plasmon band, UV-visible absorption spectra show features in the UV range which indicates also the presence of small silver clusters, such as Ag42+. The increase of the plasmon...

  20. Micro-spectroscopic techniques applied to characterization of varnished archeological findings

    Science.gov (United States)

    Barone, G.; Ioppolo, S.; Majolino, D.; Migliardo, P.; Ponterio, R.

    2000-04-01

    This work reports an analysis on terracotta varnished finding recovered in east Sicily area (Messina). We have performed FTIR micro-spectroscopy and electronic microscopy (SEM)measurements in order to recognize the elemental constituents of the varnished surfaces. Furthermore, for all the samples, a study on the bulk has been performed by Fourier Transform Infrared Absorption. The analyzed samples consist of a number of pottery fragments belonging to archaic and classical ages, varnished in black and red colors. The obtained data furnished useful information about composition of decorated surfaces and bulk matrixes, about baking temperature, manufacture techniques and alteration mechanisms of findings due to the long burial.

  1. Surface enhanced Raman spectroscopic studies of 1H-indazole on silver sols.

    Science.gov (United States)

    Pergolese, B; Bigotto, A

    2001-05-01

    The SER spectra of 1H-indazole adsorbed on silver hydrosol were recorded in the 1800-100 cm(-1) and in the 3200-2800 cm(-1) regions. The SERS data were interpreted on the basis of previous vibrational assignments, with the help of the results of DFT calculations carried out using the 6-31G** basis. From the comparison of SER and normal Raman spectra it can be deduced that 1H-indazole is non-dissociatively adsorbed on metal surface and that it interacts with silver sol via nitrogen atoms and ring pi-system. The molecular plane assumes a tilted orientation with respect to the silver surface. The effect of varying the concentration of adsorbate was also evaluated. The observed changes of the relative intensities of some enhanced bands suggest that the molecule assumes a more tilted orientation upon lowering the concentration of the adsorbate.

  2. Facile fabrication of dendritic silver structures and their surface enhanced Raman spectroscopic properties

    Indian Academy of Sciences (India)

    Jisheng Yang; Zhengdong Jiang

    2015-01-01

    A simple and efficient approach was developed to fabricate silver dendrites by Cu reducing Ag+ in AgNO3 solution. The growth speed, morphologies and structures of the silver dendrites strongly depend on AgNO3 concentration and reaction time. The silver dendrites were formed from nanosheets and the crystal structure is face-centered cubic. Rhodamine 6G was used as probe molecule to show that the silver dendrites have high sensitivity to surface enhanced Raman spectroscopy response.

  3. Spectroscopic study of surface enhanced Raman scattering of caffeine on borohydride-reduced silver colloids

    Science.gov (United States)

    Chen, Xiaomin; Gu, Huaimin; Shen, Gaoshan; Dong, Xiao; Kang, Jian

    2010-06-01

    The surface enhanced Raman scattering (SERS) of caffeine on borohydride-reduced silver colloids system under different aqueous solution environment has been studied in this paper. The relative intensity of SERS of caffeine significantly varies with different concentrations of sodium chloride and silver particles. However, at too high or too low concentration of sodium chloride and silver particle, the enhancement of SERS spectra is not evident. The SERS spectra of caffeine suggest that the contribution of the charge transfer mechanism to SERS may be dominant. The chloride ions can significantly enhance the efficiency of SERS, while the enhancement is selective, as the efficiency in charge transfer enhancement is higher than in electromagnetic enhancement. Therefore, it can be concluded that the active site of chloride ion locates on the bond between the caffeine and the silver surface. In addition, the SERS spectra of caffeine on borohydride-reduced and citrate-reduced silver colloids are different, which may be due to different states caffeine adsorbed on silver surface under different silver colloids.

  4. A spectroscopic method for the evaluation of surface passivation treatments on metal–oxide–semiconductor structures

    Energy Technology Data Exchange (ETDEWEB)

    Walsh, Lee A., E-mail: lee.walsh36@mail.dcu.ie [School of Physical Sciences, Dublin City University, Glasnevin, Dublin 9 (Ireland); Hurley, Paul K.; Lin, Jun [Tyndall National Institute, University College Cork, Lee Maltings, Cork (Ireland); Cockayne, Eric [National Institute of Standards and Technology, Gaithesburg, MD 20899 (United States); O’Regan, T.P. [U.S. Army Research Laboratory, Adelphi, MD 20783 (United States); Woicik, Joseph C. [National Institute of Standards and Technology, Gaithesburg, MD 20899 (United States); Hughes, Greg [School of Physical Sciences, Dublin City University, Glasnevin, Dublin 9 (Ireland)

    2014-05-01

    Highlights: • Surface potential changes can be detected from HAXPES measurements. • Flat band voltage shifts can be detected from HAXPES measurements. • Agreement between HAXPES and C–V measurements in Si based MOS structures. • Agreement between HAXPES and C–V measurements in GaAs based MOS structures. - Abstract: Combined hard x-ray photoelectron spectroscopy (HAXPES) and electrical characterisation measurements have been shown to provide complementary information on the electrical performance of Si and GaAs based metal–oxide–semiconductor (MOS) structures. The results obtained indicate that surface potential changes at the semiconductor/dielectric interface due to the presence of different work function metals can be detected from HAXPES measurements. Changes in the semiconductor band bending at zero gate voltage and the flat band voltage values derived from C–V measurements are in agreement with the semiconductor core level shifts measured from the HAXPES spectra. These results highlight the potential application of this measurement approach in the evaluation of the efficacy of surface passivation treatments: HAXPES—hard x-ray photoelectron spectroscopy; C–V—capacitance voltage; D{sub it}—interface state density; BE—binding energy, at reducing defect states densities in MOS structures.

  5. Molecular structure, experimental and theoretical spectroscopic characterization and non-linear optical properties studies of a new non-centrosymmetric hybrid material

    Science.gov (United States)

    Chihaoui, Nejla; Hamdi, Besma; Dammak, Thameur; Zouari, Ridha

    2016-11-01

    This paper gathers the synthesis and study of a novel nonlinear organic-inorganic (1,2-diammoniumcyclohexane tetrabromozincate (II) monohydrate; [C6H10(NH3)2]ZnBr4·H2O) hybrid. The newly developed hybrid was characterized by XRD and spectroscopic (FT-IR, Raman, UV-Visible and CP/MAS-NMR) studies. All theoretical calculations and structural optimization parameters were conducted by using DFT approach with B3LYP/6-31G(d) basis set and the vibrational wavenumbers were evaluated for the affectation of [C6H10(NH3)2]ZnBr4·H2O compound by using transferable scale factor. The inspection of intermolecular links in the studied framework has been executed by the Hirshfeld surface analysis. The nonlinear optical characteristics of this compound were theoretically explored also the molecular orbitals (HOMO) and (LUMO) properties are performed to describe the charge transfer within the crystal.

  6. Green preparation and spectroscopic characterization of plasmonic silver nanoparticles using fruits as reducing agents

    Directory of Open Access Journals (Sweden)

    Jes Ærøe Hyllested

    2015-01-01

    Full Text Available Chemicals typically available in plants have the capability to reduce silver and gold salts and to create silver and gold nanoparticles. We report the preparation of silver nanoparticles with sizes between 10 and 300 nm from silver nitrate using fruit extract collected from pineapples and oranges as reducing agents. The evolvement of a characteristic surface plasmon extinction spectrum in the range of 420 nm to 480 nm indicates the formation of silver nanoparticles after mixing silver nitrate solution and fruit extract. Shifts in plasmon peaks over time indicate the growth of nanoparticles. Electron microscopy shows that the shapes of the nanoparticles are different depending on the fruit used for preparation. The green preparation process can result in individual nanoparticles with a very poor tendency to form aggregates with narrow gaps even when aggregation is forced by the addition of NaCl. This explains only modest enhancement factors for near-infrared-excited surface enhanced Raman scattering. In addition to the surface plasmon band, UV–visible absorption spectra show features in the UV range which indicates also the presence of small silver clusters, such as Ag42+. The increase of the plasmon absorption correlates with the decrease of absorption band in the UV. This confirms the evolution of silver nanoparticles from silver clusters. The presence of various silver clusters on the surface of the “green” plasmonic silver nanoparticles is also supported by a strong multicolor luminesce signal emitted by the plasmonic particles during 473 nm excitation.

  7. Spectroscopic constraints on Pluto's coupled surface and atmosphere: context for the New Horizons encounter

    Science.gov (United States)

    Young, Eliot F.

    2017-01-01

    Pluto's bright surface is a direct result of the transport of volatiles on seasonal timescales. Over the course of a Pluto year (248 years), nitrogen, CO and methane frosts migrate over different parts of Pluto's surface. Pluto's atmosphere is predominantly N2 gas, supported by the vapor pressure of nitrogen frost -- the most volatile of Pluto's surface constituents. New Horizons obtained spectral image cubes of Pluto's surface in the 2 - 2.5 µm range, where N2, CO, CH4 and other frosts have diagnostic features. Some of the surprising results from New Horizons were the inhomogeneity of N2 frost distribution (why is there "Tombaugh Regio," a concentration of bright N2 frost?) and CH4 frost features on certain topographic locations. Given that the vapor pressure of N2 frost is about five orders of magnitude higher than that of CH4 at a given temperature, one might expect Pluto's seasonal warming and cooling cycles to act as a massive distillery and separate N2 and CH4 frosts. Ground-based spectroscopy from Keck using NIRSPEC extends our spectroscopy of Pluto to the 2.8 - 3.5 µm range, beyond New Horizon's limit. We see that the 3.3 µm band of methane frost is nearly zero, ruling out any N2 frost on Pluto that does not have CH4 frost mixed in. Furthermore, the edge of the 3.3 µm feature is diagnostic of pure CH4 ice vs. CH4 that is mixed in an N2 matrix. The mixed state of N2 and CH4 ices, a surprise given their drastically different vapor pressures, has changed the paradigm of how Pluto's surface frosts and atmosphere are coupled. In particular, Keck spectra help us extend the snapshot of the New Horizons flyby to models of volatile transport that span an entire Pluto orbit. Certain scenarios are prohibited, such as the case where Pluto's atmosphere freezes out during aphelion. Some of the lessons learned for Pluto's seasonal atmospheric behavior can be applied to other frost-covered TNOs in highly eccentric orbits, like Eris or Makemake.

  8. Complex of hexamethylenetetramine with magnesium-tetraphenylporphyrin: Synthesis, structure, spectroscopic characterizations and electrochemical properties

    Science.gov (United States)

    Ezzayani, Khaireddine; Ben Khelifa, Arbia; Saint-Aman, Eric; Loiseau, Frederique; Nasri, Habib

    2017-06-01

    A new crystalline material of a magnesium (II)-porphyrin complex was prepared and characterized by single crystal X-ray diffraction. The molecular structure is made by (5,10,15,20-tetraphenylporphyrinato-κ4N)bis(hexamethylenetetramine) magnesium dichloromethane disolvate. The title compound crystallizes in the orthorhombic system, space group Pbcn, with a = 19.2932 (6) Å, b = 10.4878 (4) Å, c = 26.0025 (14) Å, V = 5261.4 (4) Å3 and Z = 4. The supramolecular architecture includes weak C__H⋯N hydrogen bond. This magnesium-porphyrin species was also characterized by UV-visible, IR and fluorescence spectroscopy and a cyclic voltammetry investigation was also carried out on this species.

  9. Melanin from the nitrogen-fixing bacterium Azotobacter chroococcum: a spectroscopic characterization.

    Science.gov (United States)

    Banerjee, Aulie; Supakar, Subhrangshu; Banerjee, Raja

    2014-01-01

    Melanins, the ubiquitous hetero-polymer pigments found widely dispersed among various life forms, are usually dark brown/black in colour. Although melanins have variety of biological functions, including protection against ultraviolet radiation of sunlight and are used in medicine, cosmetics, extraction of melanin from the animal and plant kingdoms is not an easy task. Using complementary physicochemical techniques (i.e. MALDI-TOF, FTIR absorption and cross-polarization magic angle spinning solid-state (13)C NMR), we report here the characterization of melanins extracted from the nitrogen-fixing non-virulent bacterium Azotobacter chroococcum, a safe viable source. Moreover, considering dihydroxyindole moiety as the main constituent, an effort is made to propose the putative molecular structure of the melanin hetero-polymer extracted from the bacterium. Characterization of the melanin obtained from Azotobacter chroococcum would provide an inspiration in extending research activities on these hetero-polymers and their use as protective agent against UV radiation.

  10. Characterizing Surface Transport Barriers in the South China Sea

    Science.gov (United States)

    2015-09-30

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Characterizing Surface Transport Barriers in the South...in mathematical methods for detecting key Lagrangian transport structures in velocity field data sets for spatially complex, time- dependent, ocean...surface flows. Such transport structures are typically not inherently obvious in snapshots of the Eulerian velocity field and require analysis

  11. SEM, magnetization and Mössbauer spectroscopic characterization of Fe-U sequestration

    Science.gov (United States)

    Pal, Sangita; Meena, Sher Singh; Chowdhury, Supratik Roy; Prajapat, C. L.; Goswami, D.

    2017-05-01

    The Jekyll and Hyde nature of iron and uranium loaded "IN-HOUSE' resin viz., Polyacrylamide hydroxamic acid (PAAHA) has been characterized by FT-IR, SEM, Mössbauer spectroscopy, EDXRF and magnetization measurements techniques. Among all Mössbauer spectra and magnetization properties indicates supportive documents of characteristic special acquaintance nature of iron w.r.t accumulated U within the matrix even after loading of Fe in vast.

  12. Accurate spectroscopic characterization of ethyl mercaptan and dimethyl sulfide isotopologues: a route toward their astrophysical detection

    Energy Technology Data Exchange (ETDEWEB)

    Puzzarini, C. [Dipartimento di Chimica, " Giacomo Ciamician," Università diBologna, Via F. Selmi 2, I-40126 Bologna (Italy); Senent, M. L. [Departamento de Química y Física Teóricas, Institsuto de Estructura de la Materia, IEM-C.S.I.C., Serrano 121, Madrid E-28006 (Spain); Domínguez-Gómez, R. [Doctora Vinculada IEM-CSIC, Departamento de Ingeniería Civil, Cátedra de Química, E.U.I.T. Obras Públicas, Universidad Politécnica de Madrid (Spain); Carvajal, M. [Departamento de Física Aplicada, Facultad de Ciencias Experimentales, Unidad Asociada IEM-CSIC-U.Huelva, Universidad de Huelva, E-21071 Huelva (Spain); Hochlaf, M. [Université Paris-Est, Laboratoire de Modélisation et Simulation Multi Echelle, MSME UMR 8208 CNRS, 5 boulevard Descartes, F-77454 Marne-la-Vallée (France); Al-Mogren, M. Mogren, E-mail: cristina.puzzarini@unibo.it, E-mail: senent@iem.cfmac.csic.es, E-mail: rosa.dominguez@upm.es, E-mail: miguel.carvajal@dfa.uhu.es, E-mail: majdi.hochlaf@u-pem.fr, E-mail: mmogren@ksu.edu.sa [Chemistry Department, Faculty of Science, King Saud University, PO Box 2455, Riyadh 11451 (Saudi Arabia)

    2014-11-20

    Using state-of-the-art computational methodologies, we predict a set of reliable rotational and torsional parameters for ethyl mercaptan and dimethyl sulfide monosubstituted isotopologues. This includes rotational, quartic, and sextic centrifugal-distortion constants, torsional levels, and torsional splittings. The accuracy of the present data was assessed from a comparison to the available experimental data. Generally, our computed parameters should help in the characterization and the identification of these organo-sulfur molecules in laboratory settings and in the interstellar medium.

  13. Characterization of Pectin Nanocoatings at Polystyrene and Titanium Surfaces

    DEFF Research Database (Denmark)

    Gurzawska, Katarzyna; Dirscherl, Kai; Yihua, Yu;

    2013-01-01

    study was to physically characterize and compare polystyrene and titanium surfaces nanocoated with different Rhamnogalacturonan-Is (RG-I) and to visualize RG-I nanocoatings. RG-Is from potato and apple were coated on aminated surfaces of polystyrene, titianium discs and titanium implants...... wettability, without any major effect on surface roughness (Sa, Sdr). Furthermore, we demonstrated that it is possible to visualize the pectin RG-Is molecules and even the nanocoatings on titanium surfaces, which have not been presented before. The comparison between polystyrene and titanium surface showed...

  14. First fully ab initio potential energy surface of methane with a spectroscopic accuracy

    Science.gov (United States)

    Nikitin, A. V.; Rey, M.; Tyuterev, Vl. G.

    2016-09-01

    Full 9-dimensional ab initio potential energy surfaces for the methane molecule are constructed using extended electronic structure coupled-cluster calculations with various series of basis sets following increasing X cardinal numbers: cc-pVXZ (X = 3, 4, 5, 6), aug-cc-ACVXZ (X = 3, 4, 5), and cc-pCVXZ-F12 (X = 3, 4). High-order dynamic electron correlations including triple and quadrupole excitations as well as relativistic and diagonal Born-Oppenheimer breakdown corrections were accounted for. Analytical potential functions are parametrized as non-polynomial expansions in internal coordinates in irreducible tensor representation. Vibrational energy levels are reported using global variational nuclear motion calculations with exact kinetic energy operator and a full account of the tetrahedral symmetry of CH4. Our best ab initio surface including above-mentioned contributions provides the rms (obs.-calc.) errors of less than 0.11 cm-1 for vibrational band centers below 4700 cm-1, and ˜0.3 cm-1 for all 229 assigned experimentally determined vibrational levels up to the Icosad range <7900 cm-1 without empirically adjusted parameters. These results improve the accuracy of ab initio methane vibrational predictions by more than an order of magnitude with respect to previous works. This is an unprecedented accuracy of first-principles calculations of a five-atomic molecule for such a large data set. New ab initio potential results in significantly better band center predictions even in comparison with best available empirically corrected potential energy surfaces. The issues related to the basis set extrapolation and an additivity of various corrections at this level of accuracy are discussed.

  15. Characterization of micro machined surface from TRIP/TWIP steels

    Directory of Open Access Journals (Sweden)

    Smaga M.

    2015-01-01

    Full Text Available In this contribution micro machining induced changes in surface morphology, including phase transformation from fcc-austenite into hcp- and bcc-martensite as well as defined surface topography of TRIP/TWIP steel was characterized by scanning electron microscopy using electron backscatter diffraction (EBSD technique. For this, applying micro milling and micro grinding processes with tool diameter of 45 µm, structures were machined into flat specimen surfaces of X30MnAl17–1 steel in defined areas previously characterized by EBSD.

  16. Combined X-Ray and Raman Spectroscopic Techniques for the Characterization of Sea Spray Aerosol

    Science.gov (United States)

    Aller, J. Y.; Alpert, P. A.; Knopf, D. A.; Kilthau, W.; Bothe, D.; Charnawskas, J. C.; Gilles, M. K.; OBrien, R. E.; Moffet, R.; Radway, J.

    2014-12-01

    Sea spray aerosol along with mineral dust dominates the global mass flux of particles to the atmosphere. Marine aerosol particles are of particular interest because of their continual impact on cloud formation, precipitation, atmospheric chemical processes, and thus global climate. Here we report on the physical/chemical characteristics of sub-surface waters, aerosolized sea spray particles, and particles/organic species present in surface microlayer (SML) samples collected during oceanic field campaigns and generated during laboratory experiments, revealing a biogenic primary source of the organic fraction of airborne particles. We also report on ice nucleation experiments with aerosolized particles collected during the May 2014 WACS II North Atlantic cruise and with laboratory generated exudate material from diatom cultures with the potential to impact cirrus and mixed phase clouds. Physicochemical analyses using a multi-modal approach which includes Scanning Transmission X-ray Microscopy coupled with Near-Edge Absorption Fine Structure Spectroscopy (STXM/NEXAFS) and Raman spectroscopy confirm the presence and chemical similarity of polysaccharide-rich transparent exopolymer (TEP) material and proteins in both SML sea spray aerosol and ice forming aerosol particles, regardless of the extent of biological activity in surface waters. Our results demonstrate a direct relationship between the marine environment and composition of marine aerosol through primary particle emission.

  17. Auger electron spectroscopic study of CO{sub 2} adsorption on Zircaloy-4 surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Stojilovic, N.; Farkas, N. [Institute for Teaching and Learning and Departments of Physics and Chemistry, University of Akron, Akron, OH 44325-6236 (United States); Ramsier, R.D. [Institute for Teaching and Learning and Departments of Physics and Chemistry, University of Akron, Akron, OH 44325-6236 (United States)], E-mail: rex@uakron.edu

    2008-02-28

    We investigate the adsorption of CO{sub 2} onto Zircaloy-4 (Zry-4) surfaces at 150, 300 and 600 K using Auger electron spectroscopy (AES). Following CO{sub 2} adsorption at 150 K the graphitic form of carbon is detected, whereas upon chemisorption at 300 and 600 K we detect the carbidic phase. As the adsorption temperature is increased, the carbon Auger signal increases, whereas the oxygen signal decreases. Adsorption at all three temperatures results in a shift of the Zr Auger features, indicating surface oxidation. The effect of adsorbed CO{sub 2} on the Zr(MVV) and Zr(MNV) transitions depends on adsorption temperature and is less pronounced at higher temperatures. On the other hand, changes in the Zr(MNN) feature are similar for all three adsorption temperatures. The changes in the Zr Auger peak shapes and positions are attributed to oxygen from dissociated CO{sub 2}, with the differences observed at various temperatures indicative of the diffusion of oxygen into the subsurface region.

  18. Elemental and spectroscopic characterization of fractions of an acidic extract of oil sands process water.

    Science.gov (United States)

    Jones, D; Scarlett, A G; West, C E; Frank, R A; Gieleciak, R; Hager, D; Pureveen, J; Tegelaar, E; Rowland, S J

    2013-11-01

    'Naphthenic acids' (NAs) in petroleum produced water and oil sands process water (OSPW), have been implicated in toxicological effects. However, many are not well characterized. A method for fractionation of NAs of an OSPW was used herein and a multi-method characterization of the fractions conducted. The unfractionated OSPW acidic extract was characterized by elemental analysis, electrospray ionization-Orbitrap-mass spectrometry (ESI-MS), and an esterified extract by Fourier Transform infrared (FTIR) and ultraviolet-visible (UV) absorption spectroscopy and by comprehensive multidimensional gas chromatography-MS (GCxGC-MS). Methyl esters were fractionated by argentation solid phase extraction (Ag(+) SPE) and fractions eluting with: hexane; diethyl ether: hexane and diethyl ether, examined. Each was weighed, examined by elemental analysis, FTIR, UV, GC-MS and GCxGC-MS (both nominal and high resolution MS). The ether fraction, containing sulfur, was also examined by GCxGC-sulfur chemiluminescence detection (GCxGC-SCD). The major ions detected by ESI-MS in the OSPW extract were assigned to alicyclic and aromatic 'O2' acids; sulfur was also present. Components recovered by Ag(+) SPE were also methyl esters of alicyclic and aromatic acids; these contained little sulfur or nitrogen. FTIR spectra showed that hydroxy acids and sulfoxides were absent or minor. UV spectra, along with the C/H ratio, further confirmed the aromaticity of the hexane:ether eluate. The more minor ether eluate contained further aromatics and 1.5% sulfur. FTIR spectra indicated free carboxylic acids, in addition to esters. Four major sulfur compounds were detected by GCxGC-SCD. GCxGC-high resolution MS indicated these were methyl esters of C18 S-containing, diaromatics with ≥C3 carboxylic acid side chains. Copyright © 2013 Crown Copyright and Elsevier Ltd. Published by Elsevier Ltd.. All rights reserved.

  19. Synthesis, spectroscopic characterization and electronic structure of some new Cu(I) carbene complexes

    Indian Academy of Sciences (India)

    Chinnappan Sivasankar; Christina Baskaran; Ashoka G Samuelson

    2006-05-01

    Reaction of oligomeric Cu(I) complexes [Cu{-S-C(=NR)(O-Ar-CH3)}] with Lewis acids gave Cu(I) carbene complexes, which were characterized by 1H and 13C NMR spectroscopy. Cu(I) carbene complexes could be directly generated from RNCS, Cu(I)-OAr and Lewis acids; this method can be used to prepare Cu(I) carbene complexes with different substitutents on the carbene carbon. The complexes were unreactive towards olefins and do not undergo cyclopropanation. Electronic structure calculations (DFT) show that the charge on the carbene carbon plays an important role in controlling the reactivity of the carbene complex.

  20. Synchronous luminescence spectroscopic characterization of blood elements of normal and patients with cervical cancer

    Science.gov (United States)

    Muthuvelu, K.; Shanmugam, Sivabalan; Koteeswaran, Dornadula; Srinivasan, S.; Venkatesan, P.; Aruna, Prakasarao; Ganesan, Singaravelu

    2011-03-01

    In this study the diagnostic potential of synchronous luminescence spectroscopy (SLS) technique for the characterization of normal and different pathological condition of cervix viz., moderately differentiated squamous cell carcinoma (MDSCC), poorly differentiated squamous cell carcinoma (PDSCC) and well differentiated squamous cell carcinoma (WDSSC). Synchronous fluorescence spectra were measured for 70 abnormal cases and 30 normal subjects. Characteristic, highly resolved peaks and significant spectral differences between normal and MDSCC, PDSCC and WDSCC cervical blood formed elements were obtained. The synchronous luminescence spectra of formed elements of normal and abnormal cervical cancer patients were subjected to statistical analysis. Synchronous luminescence spectroscopy provides 90% sensitivity and 92.6% specificity.

  1. EPR, UV-Visible, and Near-Infrared Spectroscopic Characterization of Dolomite

    OpenAIRE

    S. Lakshmi Reddy; Frost, R. L.; G. Sowjanya; Reddy, N. C. G.; G. Siva Reddy; Reddy, B. J.

    2008-01-01

    Dolomite mineral samples having white and light green colors of Indian origin have been characterized by EPR, optical, and NIR spectroscopy. The optical spectrum exhibits a number of electronic bands due to presence of Fe(III) ions in the mineral. From EPR studies, the parameters of g for Fe(III) and g,A, and D for Mn(II) are evaluated and the data confirm that the ions are in distorted octahedron. Optical absorption studies reveal that Fe(III) is in distorted octahedron. The bands in NIR spe...

  2. Theoretical spectroscopic characterization at low temperatures of methyl hydroperoxide and three S-analogs

    Energy Technology Data Exchange (ETDEWEB)

    Dalbouha, S., E-mail: samiradalbouha@gmail.com; Senent, M. L., E-mail: senent@iem.cfmac.csic.es [Departamento de Química y Física Teóricas, Instituto de Estructura de la Materia, IEM-C.S.I.C., Serrano 121, Madrid 28006 (Spain); Komiha, N., E-mail: komiha@fsr.ac.ma [LS3ME-Équipe de Chimie Théorique et Modélisation, Faculté des Sciences, Université Mohamed V—Agdal, Rabat (Morocco)

    2015-02-21

    The low temperature spectra of the detectable species methyl hydroperoxide (CH{sub 3}OOH) and three sulfur analogs, the two isomers of methanesulfenic acid (CH{sub 3}SOH and CH{sub 3}OSH) and the methyl hydrogen disulfide (CH{sub 3}SSH), are predicted from highly correlated ab initio methods (CCSD(T) and CCSD(T)-F12). Rotational parameters, anharmonic frequencies, torsional energy barriers, torsional energy levels, and their splittings are provided. Our computed parameters should help for the characterization and the identification of these organic compounds in laboratory and in the interstellar medium.

  3. Surface Sensitive Techniques for Advanced Characterization of Luminescent Materials.

    Science.gov (United States)

    Swart, Hendrik C

    2017-08-04

    The important role of surface sensitive characterization techniques such as Auger electron spectroscopy (AES), X-ray photo electron spectroscopy (XPS), time of flight scanning ion mass spectrometry (TOF-SIMS) and High resolution transmission electron microscopy (HRTEM) for the characterization of different phosphor materials is discussed in this short review by giving selective examples from previous obtained results. AES is used to monitor surface reactions during electron bombardment and also to determine the elemental composition of the surfaces of the materials, while XPS and TOF-SIMS are used for determining the surface chemical composition and valence state of the dopants. The role of XPS to determine the presence of defects in the phosphor matrix is also stated with the different examples. The role of HRTEM in combination with Energy dispersive spectroscopy (EDS) for nanoparticle characterization is also pointed out.

  4. Application of imaging spectroscopic reflectometry for characterization of gold reduction from organometallic compound by means of plasma jet technology

    Science.gov (United States)

    Vodák, Jiří; Nečas, David; Pavliňák, David; Macak, Jan M.; Řičica, Tomáš; Jambor, Roman; Ohlídal, Miloslav

    2017-02-01

    This work presents a new application of imaging spectroscopic reflectometry to determine a distribution of metallic gold in a layer of an organogold precursor which was treated by a plasma jet. Gold layers were prepared by spin coating from a solution of the precursor containing a small amount of polyvinylpyrrolidone on a microscopy glass, then they were vacuum dried. A difference between reflectivity of metallic gold and the precursor was utilized by imaging spectroscopic reflectometry to create a map of metallic gold distribution using a newly developed model of the studied sample. The basic principle of the imaging spectroscopic reflectometry is also shown together with the data acquisition principles. XPS measurements and microscopy observations were made to complete the imaging spectroscopic reflectometry results. It is proved that the imaging spectroscopic reflectometry represents a new method for quantitative evaluation of local reduction of metallic components from metaloorganic compounds.

  5. Alternating current impedance spectroscopic analysis of biofunctionalized vertically-aligned silica nanospring surface for biosensor applications

    Science.gov (United States)

    Timalsina, Yukta P.

    In this dissertation, a process of vertically-aligned (silica) nanosprings (VANS) based biosensor development is presented. Alternating current (AC) impedance spectroscopy has been used to analyze sensor response as a function of saline phosphate (SP) buffer and biological solutions. The sensor is a parallel plate capacitor consisting of two glass substrates coated with indium tin oxide (ITO), where the VANS [or randomly-aligned nanosprings (RANS)] grown on one substrate serve as the dielectric spacer layer. The response of a VANS device as a function of ionic concentration in SP buffer was examined and an equivalent circuit model was developed. The results demonstrated that VANS sensors exhibited greater sensitivity to the changes in SP concentration relative to the ITO sensors, which serve as controls. The biofunctionalized VANS surface via physisorption and the cross-linker method demonstrates the repeatability, specificity, and selectivity of the binding. The physisorption of biotinylated immunoglobulin G (B-IgG) onto the VANS surface simplifies the whole sensing procedure for the detection of glucose oxidase, since the avidin-conjugated glucose oxidase (Av-GOx) can directly be immobilized on the B-IgG. The cross linker method involves the covalent attachment of antibodies onto the functionalized VANS surface via imine bond. The experiments revealed that the VANS sensor response is solely the result of the interaction of target molecule i.e. mouse IgG with the probe layer, i.e. goat antimouse IgG (GalphaM IgG). It was determined that VANS-based sensors exhibit a greater magnitude of change between successive bio-layers relative to the controls above 100 Hz, which indicates that the addition of biomolecules inhibits the diffusion of ions and changes the effective dielectric response of the VANS via biomolecular polarization. The study of ionic transport in nanosprings suggested that conductance follows a scaling law. It was demonstrated that a VANS-based device

  6. Melanin from the nitrogen-fixing bacterium Azotobacter chroococcum: a spectroscopic characterization.

    Directory of Open Access Journals (Sweden)

    Aulie Banerjee

    Full Text Available Melanins, the ubiquitous hetero-polymer pigments found widely dispersed among various life forms, are usually dark brown/black in colour. Although melanins have variety of biological functions, including protection against ultraviolet radiation of sunlight and are used in medicine, cosmetics, extraction of melanin from the animal and plant kingdoms is not an easy task. Using complementary physicochemical techniques (i.e. MALDI-TOF, FTIR absorption and cross-polarization magic angle spinning solid-state (13C NMR, we report here the characterization of melanins extracted from the nitrogen-fixing non-virulent bacterium Azotobacter chroococcum, a safe viable source. Moreover, considering dihydroxyindole moiety as the main constituent, an effort is made to propose the putative molecular structure of the melanin hetero-polymer extracted from the bacterium. Characterization of the melanin obtained from Azotobacter chroococcum would provide an inspiration in extending research activities on these hetero-polymers and their use as protective agent against UV radiation.

  7. Spectroscopic characterization of metal complexes of novel Schiff base. Synthesis, thermal and biological activity studies.

    Science.gov (United States)

    Omar, M M; Mohamed, Gehad G; Ibrahim, Amr A

    2009-07-15

    Novel Schiff base (HL) ligand is prepared via condensation of 4-aminoantipyrine and 2-aminobenzoic acid. The ligand is characterized based on elemental analysis, mass, IR and (1)H NMR spectra. Metal complexes are reported and characterized based on elemental analyses, IR, (1)H NMR, solid reflectance, magnetic moment, molar conductance and thermal analyses (TGA, DrTGA and DTA). The molar conductance data reveal that all the metal chelates are non-electrolytes. IR spectra show that HL is coordinated to the metal ions in a uninegatively tridentate manner with NNO donor sites of the azomethine N, amino N and deprotonated caroxylic-O. From the magnetic and solid reflectance spectra, it is found that the geometrical structures of these complexes are octahedral. The thermal behaviour of these chelates shows that the hydrated complexes losses water molecules of hydration in the first step followed immediately by decomposition of the anions and ligand molecules in the subsequent steps. The activation thermodynamic parameters, such as, E*, DeltaH*, DeltaS* and DeltaG* are calculated from the DrTG curves using Coats-Redfern method. The synthesized ligands, in comparison to their metal complexes also were screened for their antibacterial activity against bacterial species, Escherichia Coli, Pseudomonas aeruginosa, Staphylococcus Pyogones and Fungi (Candida). The activity data show that the metal complexes to be more potent/antibacterial than the parent Shciff base ligand against one or more bacterial species.

  8. Solvate Structures and Computational/Spectroscopic Characterization of LiBF4 Electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Seo, D. M.; Boyle, Paul D.; Allen, Joshua L.; Han, Sang D.; Jonsson, Erlendur; Johansson, Patrik; Henderson, Wesley A.

    2014-07-21

    Crystal structures have been determined for both LiBF4 and HBF4 solvates—(acetonitrile)2:LiBF4, (ethylene glycol diethyl ether)1:LiBF4, (diethylene glycol diethyl ether)1:LiBF4, (tetrahydrofuran)1:LiBF4, (methyl methoxyacetate)1:LiBF4, (suc-cinonitrile)1:LiBF4, (N,N,N',N",N"-pentamethyldiethylenetriamine)1:HBF4, (N,N,N',N'-tetramethylethylenediamine)3/2:HBF4 and (phenanthroline)2:HBF4. These, as well as other known LiBF4 solvate structures, have been characterized by Raman vibrational spectroscopy to unambiguously assign the anion Raman band positions to specific forms of BF4-...Li+ cation coordination. In addition, complementary DFT calculations of BF4-...Li+ cation complexes have provided additional insight into the challenges associated with accurately interpreting the anion interactions from experimental Raman spectra. This information provides a crucial tool for the characterization of the ionic association interactions within electrolytes.

  9. Synthesis, spectroscopic characterization, DFT optimization and biological activities of Schiff bases and their metal (II) complexes

    Science.gov (United States)

    Rauf, Abdur; Shah, Afzal; Munawar, Khurram Shahzad; Khan, Abdul Aziz; Abbasi, Rashda; Yameen, Muhammad Arfat; Khan, Asad Muhammad; Khan, Abdur Rahman; Qureshi, Irfan Zia; Kraatz, Heinz-Bernhard; Zia-ur-Rehman

    2017-10-01

    A Novel Schiff base, 3-(((4-chlorophenyl)imino)methyl)benzene-1,2-diol (HL1) was successfully synthesized along with a structurally similar Schiff base 3-(((4-bromophenyl)imino)methyl)benzene-1,2-diol (HL2). Both the Schiff bases were used to synthesize their zinc (II) and cobalt (II) complexes. These compounds were characterized by FTIR, 1H NMR, 13C NMR and elemental analysis. Metal complexes were confirmed by TGA. Crystals of Schiff bases were also characterized by X-ray analysis and experimental parameters were found in line with the theoretical parameters. Quantum mechanical approach was also used to fine useful structural parameters and to ensure the geometry of metal complexes. The photometric behaviors of all the synthesized compounds were investigated in a wide pH range using BR buffers. The appearance of isosbestic points indicated the existence of Schiff bases in more than one isomeric form. Moreover, these compounds were screened for enzyme inhibition; antibacterial, cytotoxic and in vivo antidiabetic activities and compounds were found active against one or other activity. Results indicate that ZnL22 is a good inhibitor of alkaline phosphatase enzyme and possess highest potential against diabetes, blood cholesterol level and cancer cells. This effort just provides preliminary data for some biological properties. Further investigations are required to precisely determine mechanistic pathways of their use towards drug development.

  10. Spectroscopic Characterization of Stability and Interaction of Pd-Ag Complexes

    Directory of Open Access Journals (Sweden)

    Sharad V. Lande

    2014-01-01

    Full Text Available Colloidal metal nanoparticles are of great interest because of their use as catalysts, photocatalysts, adsorbents, and sensors as well as their application in optical, electronic, and magnetic devices. Supported bimetallic systems represent a large part of heterogeneous catalysts which have been used in various reactions important in the chemical, petrochemical, and oil industry. Pd-Ag bimetallic nanocatalysts have become vitally important in some of the petrochemical industry’s processes like hydrogenation of C2–C5 olefins. A heat-treatment method for the preparation of well-stable Pd-Ag complexes is demonstrated using water, concentrated HCl and concentrated nitric acid as media. The stability and interaction of Pd-Ag complexes were characterized by UV-vis absorption spectroscopy. Pd-Ag bimetallic nanoparticles of spherical cubic and octahedral shape in the range of average particle size of 20–60 nm have been prepared and characterized by transmission electron microscopy (TEM.

  11. Colored grounds of gilt stucco surfaces as analyzed by a combined microscopic, spectroscopic and elemental analytical approach.

    Science.gov (United States)

    Sansonetti, A; Striova, J; Biondelli, D; Castellucci, E M

    2010-08-01

    A survey of gilts applied to stucco surfaces that specifically focuses on the compositions of their colored grounds is reported. Gilt samples of a common geographical (Lombardy in Italy) and temporal provenance (17th-18th century) were studied in the form of polished cross-sections by optical and electron microscopy (SEM-EDS), micro-Raman (microRaman) spectroscopy and Fourier-transform infrared microspectroscopy (microFTIR). Comparing samples with superimposed grounds and gilts enabled light to be shed on the choice of specific materials, their stratigraphic functions, decorative effects, and technological performances. Iron oxide pigments were found in the older grounds, sometimes in the presence of lead white (2PbCO(3).Pb(OH)(2)) or minium (Pb(3)O(4)). In more recent grounds, chrome yellow (PbCrO(4)), chrome orange (PbCrO(4).PbO), cinnabar (alpha-HgS) and barium white (BaSO(4)), invariably mixed with lead white, were encountered. Evidence for the use of organic mordants (colophony and wax, or siccative oil) was obtained by microFTIR. This combined microFTIR and microRaman spectroscopic and elemental (SEM-EDS) analytical approach enhances knowledge of the composition of gold grounds, their variability and their chronological evolution.

  12. Plasmonic Dimer-Like Nanoassemblies for Surface-Enhanced Raman Spectroscop

    Science.gov (United States)

    Rigo, Maria; Seo, Jaetae; Kim, Wan-Joong; Jung, Sungsoo; Hampton University Team; Etri Collaboration; Kriss Collaboration

    2011-05-01

    We report on the preparation of gold dimers in which the near-field coupling in their subwavelength gap is influenced by the individual gold nanoparticles size and the molecule's length used to assemble the dimers. The nano assemblies display plasmonic modes similar to those observed in rod-like nanoparticles. The longitudinal mode of the gold dimers shift as a function of gold nanoparticles size and concentration and it is influenced by the concentration of Rhodamine 6G (R6G), the molecule used as nanoparticle linker. We report large surface enhanced Raman scattering (SERS) enhancements for R6G when using linked-gold nano-assemblies as a SERS substrate. A discussion about the main origins for the large enhancement of molecular vibrational modes is presented. This work at Hampton University was supported by the National Science Foundation (HRD-0734635 and HRD-0630372).

  13. Spectroscopic study on uranyl carboxylate complexes formed at the surface layer of Sulfolobus acidocaldarius.

    Science.gov (United States)

    Reitz, Thomas; Rossberg, Andre; Barkleit, Astrid; Steudtner, Robin; Selenska-Pobell, Sonja; Merroun, Mohamed L

    2015-02-14

    The complexation of U(vi) at the proteinaceous surface layer (S-layer) of the archaeal strain Sulfolobus acidocaldarius was investigated over a pH range from pH 1.5 to 6 at the molecular scale using time-resolved laser-induced fluorescence spectroscopy (TRLFS) and U L(III)-edge extended X-ray absorption fine structure (EXAFS). The S-layer, which represents the interface between the cell and its environment, is very stable against high temperatures, proteases, and detergents. This allowed the isolation and purification of S-layer ghosts (= empty cells) that maintain the size and shape of the cells. In contrast to many other microbial cell envelope compounds the studied S-layer is not phosphorylated, enabling the investigation of uranyl carboxylate complexes formed at microbial surfaces. The latter are usually masked by preferentially formed uranyl phosphate complexes. We demonstrated that at highly acidic conditions (pH 1.5 to 3) no uranium was bound by the S-layer. In contrast to that, at moderate acidic pH conditions (pH 4.5 and 6) a complexation of U(vi) at the S-layer via deprotonated carboxylic groups was stimulated. Titration studies revealed dissociation constants for the carboxylic groups of glutamic and aspartic acid residues of pK(a) = 4.78 and 6.31. The uranyl carboxylate complexes formed at the S-layer did not show luminescence properties at room temperature, but only under cryogenic conditions. The obtained luminescence maxima are similar to those of uranyl acetate. EXAFS spectroscopy demonstrated that U(vi) in these complexes is mainly coordinated to carboxylate groups in a bidentate binding mode. The elucidation of the molecular structure of these complexes was facilitated by the absence of phosphate groups in the studied S-layer protein.

  14. Spectroscopic characterization of dissolved organic matter in coking wastewater during bio-treatment: full-scale plant study.

    Science.gov (United States)

    Xu, Ronghua; Ou, Huase; Yu, Xubiao; He, Runsheng; Lin, Chong; Wei, Chaohai

    2015-01-01

    This paper taking a full-scale coking wastewater (CWW) treatment plant as a case study aimed to characterize removal behaviors of dissolved organic matter (DOM) by UV spectra and fluorescence excitation-emission matrix-parallel factor analysis (PARAFAC), and investigate the correlations between spectroscopic indices and water quality parameters. Efficient removal rates of chemical oxygen demand (COD), dissolved organic carbon (DOC) and total nitrogen (TN) after the bio-treatment were 91.3%, 87.3% and 69.1%, respectively. UV270 was proven to be a stable UV absorption peak of CWW that could reflect the mixture of phenols, heterocyclics, polynuclear aromatic hydrocarbons and their derivatives. Molecular weight and aromaticity were increased, and also the content of polar functional groups was greatly reduced after bio-treatment. Three fluorescent components were identified by PARAFAC: C1 (tyrosine-like), C2 (tryptophan-like) and C3 (humic-like). The removal rate of protein-like was higher than that of humic-like and C1 was identified as biodegradable substance. Correlation analysis showed UV270 had an excellent correlation with COD (r=0.921, n=60, Ptreatment.

  15. Crystal structure characterization as well as theoretical study of spectroscopic properties of novel Schiff bases containing pyrazole group.

    Science.gov (United States)

    Guo, Jia; Ren, Tiegang; Zhang, Jinglai; Li, Guihui; Li, Weijie; Yang, Lirong

    2012-09-01

    A series of novel Schiff bases containing pyrazole group were synthesized using 1-aryl-3-methyl-4-benzoyl-5-pyrazolone and phenylenediamine as the starting materials. All as-synthesized Schiff bases were characterized by means of NMR, FT-IR, and MS; and the molecular geometries of two Schiff bases as typical examples were determined by means of single crystal X-ray diffraction. In the meantime, the ultraviolet-visible light absorption spectra and fluorescent spectra of various as-synthesized products were also measured. Moreover, the B3LYP/6-1G(d,p) method was used for the optimization of the ground state geometry of the Schiff bases; and the spectroscopic properties of the products were computed and compared with corresponding experimental data based on cc-pVTZ basis set of TD-B3LYP method. It has been found that all as-synthesized Schiff bases show a remarkable absorption peak in a wavelength range of 270-370 nm; and their maximum emission peaks are around 344 nm and 332 nm, respectively.

  16. Spectroscopic Characterization of the Water Oxidation Intermediates in the Blue Dimer Ru-Based Catalyst for Artificial Photosynthesis

    Science.gov (United States)

    Moonshiram, Dooshaye; Pushkar, Yulia; Jurss, Jonah; Concepcion, Javier; Meyer, Thomas; Zakharova, Taisiya; Alperovich, Igor

    2012-02-01

    Utilization of sunlight requires solar capture, light-to-energy conversion and storage. One effective way to store energy is to convert it into chemical energy by fuel-forming reactions, such as water splitting into hydrogen and oxygen. Ruthenium complexes are among few molecular-defined catalysts capable of water splitting. Mechanistic insights about such catalysts can be acquired by spectroscopic analysis of short-lived intermediates of catalytic water oxidation. Use of techniques such as EPR and X-ray absorption spectroscopy (XAS) are used to determine electronic requirements of catalytic water oxidation. About 30 years ago Meyer and coworkers reported first ruthenium-based catalyst for water oxidation, the ``blue dimer''. We performed EPR studies and characterized structures and electronic configurations of intermediates of water oxidation by the ``blue dimer''. Intermediates were prepared chemically by oxidation of Ru-complexes with defined number of Ce (IV) equivalents and freeze-quenched at controlled times. Changes in oxidation state of Ru atom were detected by XANES at Ru K-edges. K-edges are sensitive to changes in Ru oxidation state for Blue Dimer [3,3]^4+, [3,4]^4+, [3,4]'^4+ and [4,5]^3+ allowing a clear assignment of Ru oxidation state in intermediates. EXAFS demonstrated structural changes.

  17. Synthesis and spectroscopic characterization of gallic acid and some of its azo complexes

    Science.gov (United States)

    Masoud, Mamdouh S.; Hagagg, Sawsan S.; Ali, Alaa E.; Nasr, Nessma M.

    2012-04-01

    A series of gallic acid and azo gallic acid complexes were prepared and characterized by elemental analysis, IR, electronic spectra and magnetic susceptibility. The complexes were of different geometries: Octahedral, Tetrahedral and Square Planar. ESR was studied for copper complexes. All of the prepared complexes were of isotropic nature. The thermal analyses of the complexes were studied by DTA and DSC techniques. The thermodynamic parameters and the thermal transitions, such as glass transitions, crystallization and melting temperatures for some ligands and their complexes were evaluated and discussed. The entropy change values, ΔS#, showed that the transition states are more ordered than the reacting complexes. The biological activities of some ligands and their complexes are tested against Gram positive and Gram negative bacteria. The results showed that some complexes have a well considerable activity against different organisms.

  18. Novel aldehyde and thiosemicarbazone derivatives: Synthesis, spectroscopic characterization, structural studies and molecular docking studies

    Science.gov (United States)

    Karakurt, Tuncay; Tahtaci, Hakan; Subasi, Nuriye Tuna; Er, Mustafa; Ağar, Erbil

    2016-12-01

    In this study our purpose is that, synthesis and characterization of compounds containing the aldehyde and thiosemicarbazone groups and comparison of the theoretical results with the experimental results. The structures of all synthesized compounds were elucidated by IR, 1H NMR, 13C NMR, elemental analyses techniques. The structure of compound (4) (C9H8N4O2S) was also elucidated by X-ray diffraction analysis. In addition, the theoretical IR spectrum, 1H NMR and 13C NMR chemical shift values, frontier molecular orbital values (FMO) of these molecules were analyzed by using Becke-3- Lee-Yang-Parr (B3LYP) method with LanL2DZ basis set. Finally, molecular docking studies were performed on synthesized compounds using the 4DKI beta-lactam protein structure to determine the potential binding mode of inhibitors.

  19. EPR, UV-Visible, and Near-Infrared Spectroscopic Characterization of Dolomite

    Directory of Open Access Journals (Sweden)

    S. Lakshmi Reddy

    2008-01-01

    Full Text Available Dolomite mineral samples having white and light green colors of Indian origin have been characterized by EPR, optical, and NIR spectroscopy. The optical spectrum exhibits a number of electronic bands due to presence of Fe(III ions in the mineral. From EPR studies, the parameters of g for Fe(III and g,A, and D for Mn(II are evaluated and the data confirm that the ions are in distorted octahedron. Optical absorption studies reveal that Fe(III is in distorted octahedron. The bands in NIR spectra are due to the overtones and combinations of water molecules. Thus EPR and optical absorption spectral studies have proven useful for the study of the solid state chemistry of dolomite.

  20. X-ray Spectroscopic Characterization of Shock-Ignition-Relevant plasmas

    Directory of Open Access Journals (Sweden)

    Michal Šmíd

    2013-01-01

    Full Text Available Experiments with multilayer plastic/Cu targets performed at a PALS laser system aimed at the study of matter at conditions relevant to a shock ignition ICF scheme, and, in particular, at the investigation of hot electrons generation. Plasma temperature and density were obtained using high-resolution X-ray spectroscopy. 2D-spatially resolved quasi–monochromatic imaging was observing the hot electrons via fluorescence K emission in the copper tracer layer. Found values of plasma temperature 690 ± 10 eV, electron density 3 × 1022 cm-3 and the effective energy of hot electrons 45 ± 20 keV demonstrate the potential of X-ray methods in the characterization of the shock ignition environmental conditions.

  1. Synthesis, spectroscopic characterization and pH dependent photometric and electrochemical fate of Schiff bases.

    Science.gov (United States)

    Rauf, Abdur; Shah, Afzal; Abbas, Saghir; Rana, Usman Ali; Khan, Salah Ud-Din; Ali, Saqib; Zia-Ur-Rehman; Qureshi, Rumana; Kraatz, Heinz-Bernhard; Belanger-Gariepy, Francine

    2015-03-05

    A new Schiff base, 1-((4-bromophenylimino) methyl) naphthalen-2-ol (BPIMN) was successfully synthesized and characterized by (1)H NMR, (13)C NMR, FTIR and UV-Vis spectroscopy. The results were compared with a structurally related Schiff base, 1-((4-chlorophenylimino) methyl) naphthalen-2-ol (CPIMN). The photometric and electrochemical fate of BPIMN and CPIMN was investigated in a wide pH range. The experimental findings were supported by quantum mechanical approach. The redox mechanistic pathways were proposed on the basis of results obtained electrochemical techniques. Moreover, pH dependent UV-Vis spectroscopy of BPIMN and CPIMN was carried out and the appearance of isosbestic points indicated the existence of these compounds in different tautomeric forms.

  2. Synthesis and spectroscopic characterization of palladium-doped titanium dioxide catalyst

    Indian Academy of Sciences (India)

    Fereshteh Chekin; Samira Bagheri; Sharifah Bee Abd Hamid

    2015-04-01

    In this work, we reported synthesis of palladium (Pd)-doped titanium dioxide (TiO2)(Pd-TiO2) nanoparticles by the sol–gel-assisted method. The synthesized Pd-doped TiO2 nanoparticles were characterized using X-ray diffraction, transmission electronic microscopy, energy-dispersive spectroscopy, Fourier transform infrared (FT-IR) spectroscopy and voltammetry techniques. The analysis showed that particles are spherical in shape and pure anatase form with average size about 10 nm. To investigate the catalytic efficiency of Pd-TiO2 nanoparticles, the hydrogen evolution reaction using the deposited film of Pd-TiO2 nanoparticles on glassy carbon electrode (Pd-TiO2/GCE) was studied in 0.1 M H2SO4 solution using linear scanning voltammetry. This study demonstrates the feasibility of using gelatin for the synthesis of Pd-TiO2 catalyst.

  3. Raman spectroscopic characterization of the core-rim structure in reaction bonded boron carbide ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Jannotti, Phillip; Subhash, Ghatu, E-mail: subhash@ufl.edu [Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, Florida 32611 (United States); Zheng, James Q.; Halls, Virginia [Program Executive Office—Soldier Protection and Individual Equipment, US Army, Fort Belvoir, Virginia 22060 (United States); Karandikar, Prashant G.; Salamone, S.; Aghajanian, Michael K. [M-Cubed Technologies, Inc., Newark, Delaware 19711 (United States)

    2015-01-26

    Raman spectroscopy was used to characterize the microstructure of reaction bonded boron carbide ceramics. Compositional and structural gradation in the silicon-doped boron carbide phase (rim), which develops around the parent boron carbide region (core) due to the reaction between silicon and boron carbide, was evaluated using changes in Raman peak position and intensity. Peak shifting and intensity variation from the core to the rim region was attributed to changes in the boron carbide crystal structure based on experimental Raman observations and ab initio calculations reported in literature. The results were consistent with compositional analysis determined by energy dispersive spectroscopy. The Raman analysis revealed the substitution of silicon atoms first into the linear 3-atom chain, and then into icosahedral units of the boron carbide structure. Thus, micro-Raman spectroscopy provided a non-destructive means of identifying the preferential positions of Si atoms in the boron carbide lattice.

  4. Lanthanide amino acid Schiff base complexes: synthesis, spectroscopic characterization, physical properties and in vitro antimicrobial studies

    Institute of Scientific and Technical Information of China (English)

    Samir Alghool; M.Sh.Zoromba; Hanan F.Abd El-Halim

    2013-01-01

    Complexes of La (Ⅲ),Nd(Ⅲ),Gd(Ⅲ),Sm(Ⅲ),and Ce(Ⅳ) were synthesized with Schiff base [(3,5-di-tert-butyl-2-hydroxybenzyl) amino] acetic acid (H3L).The ligand and its complexes were synthesized and characterized based on the following analysis:elemental analyses,FAB-mass,molar conductance measurements,magnetic measurement,UV-visible,IR,and NMR spectral studies.The spectral data revealed that the ligand acted as a neutral tridentate coordinating to metal ion through ONO donor sequence.Thermal degradation studies of the ligand and its complexes showed that the previous lanthanide complexes were more thermally stable than the ligand itself.The Schiff base and its complexes were screened for their antibacterial (Escherichia coli,Staphylococcus aureus) and antifungal (Aspergillus flavus and Candida Albicans).

  5. NMR spectroscopic characterization of β-cyclodextrin inclusion complex with vanillin

    Science.gov (United States)

    Pîrnau, Adrian; Bogdan, Mircea; Floare, Calin G.

    2009-08-01

    The inclusion of vanillin by β-cyclodextrin was investigated by 1H NMR. The continuous variation technique was used to evidence the formation of soluble 1:1 complex in aqueous solution. The association constant of vanillin with β-cyclodextrin has been obtained at 298 K by fitting the experimental chemical shifts differences, Δδobs = δfree - δobs of the observed guest and host protons, with a non-linear regression method. Besides the effective association constant, the fitting procedure allows a precise determination of all chemical shift parameters characterizing the pure complex. They can by used for an analysis of the geometry of the molecular complex in solution.

  6. NMR spectroscopic characterization of {beta}-cyclodextrin inclusion complex with vanillin

    Energy Technology Data Exchange (ETDEWEB)

    Pirnau, Adrian; Bogdan, Mircea; Floare, Calin G, E-mail: adrian.pirnau@itim-cj.r [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath, 400293 Cluj-Napoca (Romania)

    2009-08-01

    The inclusion of vanillin by {beta}-cyclodextrin was investigated by {sup 1}H NMR. The continuous variation technique was used to evidence the formation of soluble 1:1 complex in aqueous solution. The association constant of vanillin with {beta}-cyclodextrin has been obtained at 298 K by fitting the experimental chemical shifts differences, {Delta}{delta}{sub obs} {delta}{sub free} - {delta}{sub obs} of the observed guest and host protons, with a non-linear regression method. Besides the effective association constant, the fitting procedure allows a precise determination of all chemical shift parameters characterizing the pure complex. They can by used for an analysis of the geometry of the molecular complex in solution.

  7. Spectroscopic characterization of magnetic Fe3O4@Au core shell nanoparticles

    Science.gov (United States)

    Fouad, Dina M.; El-Said, Waleed A.; Mohamed, Mona B.

    2015-04-01

    The magnetic nanoparticles iron oxide (Fe3O4) nanoparticles and iron oxide/gold core-shell (Fe3O4/Au) nanoparticles were synthesized and their catalytic photo-degradation activity towards malathion as example of organophosphorus pesticides were reported. Iron oxide (Fe3O4) magnetic nanoparticle was successfully prepared through co-precipitation method by the reduction of ferric chloride (FeCl3) using ascorbic acid. The morphology of the prepared nanoparticles was characterized by the TEM and XRD (X-ray diffraction) techniques. Degradation of 10 ppm of malathion in the presence of these nanoparticles under UV radiation was monitored using (HPLC) and UV-visible spectra. Fe3O4/Au nanoparticles showed higher efficiency in photo-degradation of malathion than Fe3O4 ones.

  8. Synthesis, Spectroscopic Characterization, and Biological Activities of Metal Complexes of 4-((4-Chlorophenyldiazenyl-2-((p-tolyliminomethylphenol

    Directory of Open Access Journals (Sweden)

    C. Anitha

    2013-01-01

    Full Text Available Azo Schiff base complexes of VO(II, Mn(II, Co(II, Ni(II, Cu(II, and Zn(II have been synthesized from 4-((4-chlorophenyldiazenyl-2-((p-tolyliminomethylphenol (CDTMP. The nature of bonding and the structural features of the complexes have been deduced from elemental analysis, molar conductance, magnetic susceptibility measurements, IR, UV-Vis, 1H-NMR, EPR, mass, SEM, and fluorescence spectral studies. Spectroscopic and other analytical studies reveal square-planar geometry for copper, square-pyramidal geometry for oxovanadium, and octahedral geometry for other complexes. The EPR spectra of copper(II complex in DMSO at 300 K and 77 K were recorded, and its salient features are reported. Antimicrobial studies against several microorganisms indicate that the complexes are more potent bactericides and fungicides than the ligand. The electrochemical behavior of the copper(II complex was studied by cyclic voltammetry. All the synthesized compounds can serve as potential photoactive materials as indicated from their characteristic fluorescence properties. The second harmonic conversion efficiency of the synthesized azo Schiff base was found to be higher than that of urea and KDP (potassium dihydrogen phosphate. SEM image of copper(II complex implies the crystalline state and surface morphology of the complex.

  9. Optical, laser spectroscopic, and electrical characterization of transion metal doped zinc selenide and zinc sulfide nano-and-microcrystals

    Science.gov (United States)

    Kim, Changsu

    Middle-infrared lasers operating over a "molecular fingerprint" 2-15 mum spectral range are in great demand for a variety of applications. One of the best choices for lasing in the 2-5 mum spectral range is direct oscillation from divalent transition metal ions (TM2+: Cr 2+, Fe2+, Co2+)-doped wide bandgap II-VI semiconductor crystals. There are three major objectives in this dissertation: (1) Realize and study middle-infrared electroluminescence of n and p-type, Cr doped bulk ZnSe crystals. We have demonstrated a method of ZnSe crystals thermal-diffusion doping with donor (In, Zn, and Al) and acceptor (Cu, Ag, and N through CrN) impurities resulting in n and p-type conductivity of Cr:ZnSe. We are the first to our knowledge to obtain mid-IR electroluminescence in nominally p-type Cr:Ag:ZnSe, which could prove valuable for developing of novel mid-IR laser diodes. (2) En route to low dimensional gain material, develop simple method for making microscopic laser active Cr doped ZnSe, ZnS and CdSe powders, realize and study their laser spectroscopic characteristics. We have demonstrated a simple physical method of Cr2+:ZnSe, ZnS and CdSe powder fabrication with average sizes below ˜ 10mum and ˜1mum (eliminating stage of bulk crystal growth) and demonstrated first ever mid-IR random lasing on these powders under optical excitation. In addition, we have examine suspensions and polymer films impregnated with Cr:II-VI powders for random lasing in the mid-IR. The powder, suspension and polymer samples are fabricated and characterized through the measurement of photoluminescence (PL) spectra, PL kinetics, and lasing threshold energy. (3) En route to low dimensional gain material, develop method for making laser active Cr, Co, and Fe doped ZnSe and ZnS quantum dots (QD), realize and study their laser spectroscopic characteristics. We have demonstrated a novel method of TM doped II-VI QDs fabrication based on laser ablation in liquid and Ar environment. TM doped II-VI QDs

  10. Spectroscopic characterization approach to study surfactants effect on ZnO 2 nanoparticles synthesis by laser ablation process

    Science.gov (United States)

    Drmosh, Q. A.; Gondal, M. A.; Yamani, Z. H.; Saleh, T. A.

    2010-05-01

    Zinc peroxide nanoparticles having grain size less than 5 nm were synthesized using pulsed laser ablation in aqueous solution in the presence of different surfactants and solid zinc target in 3% H 2O 2. The effect of surfactants on the optical and structure of ZnO 2 was studied by applying different spectroscopic techniques. Structural properties and grain size of the synthesized nanoparticles were studied using XRD method. The presence of the cubic phase of zinc peroxide in all samples was confirmed with XRD, and the grain sizes were 4.7, 3.7, 3.3 and 2.8 nm in pure H 2O 2, and H 2O 2 mixed with SDS, CTAB and OGM respectively. For optical characterization, FTIR transmittance spectra of ZnO 2 nanoparticles prepared with and without surfactants show a characteristic ZnO 2 absorption at 435-445 cm -1. FTIR spectrum revealed that the adsorbed surfactants on zinc peroxide disappeared in case of CTAB and OGM while it appears in case of SDS. This could be due to high critical micelles SDS concentration comparing with others which is attributed to the adsorption anionic nature of this surfactant. Both FTIR and UV-vis spectra show a red shift in the presence of SDS and blue shift in the presence of CTAB and OGM. The blue shift in the absorption edge indicates the quantum confinement property of nanoparticles. The zinc peroxide nanoparticles prepared in additives-free media was also characterized by Raman spectra which show the characteristic peaks at 830-840 and 420-440 cm -1.

  11. Spectroscopic characterization approach to study surfactants effect on ZnO{sub 2} nanoparticles synthesis by laser ablation process

    Energy Technology Data Exchange (ETDEWEB)

    Drmosh, Q.A. [Laser Research Group, Physics Department, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Center of Excellence in Nanotechnology (CENT), King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Gondal, M.A., E-mail: magondal@kfupm.edu.sa [Laser Research Group, Physics Department, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Center of Excellence in Nanotechnology (CENT), King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Yamani, Z.H. [Laser Research Group, Physics Department, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Center of Excellence in Nanotechnology (CENT), King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Saleh, T.A. [Center of Excellence in Nanotechnology (CENT), King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Chemistry Department, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)

    2010-05-01

    Zinc peroxide nanoparticles having grain size less than 5 nm were synthesized using pulsed laser ablation in aqueous solution in the presence of different surfactants and solid zinc target in 3% H{sub 2}O{sub 2}. The effect of surfactants on the optical and structure of ZnO{sub 2} was studied by applying different spectroscopic techniques. Structural properties and grain size of the synthesized nanoparticles were studied using XRD method. The presence of the cubic phase of zinc peroxide in all samples was confirmed with XRD, and the grain sizes were 4.7, 3.7, 3.3 and 2.8 nm in pure H{sub 2}O{sub 2}, and H{sub 2}O{sub 2} mixed with SDS, CTAB and OGM respectively. For optical characterization, FTIR transmittance spectra of ZnO{sub 2} nanoparticles prepared with and without surfactants show a characteristic ZnO{sub 2} absorption at 435-445 cm{sup -1}. FTIR spectrum revealed that the adsorbed surfactants on zinc peroxide disappeared in case of CTAB and OGM while it appears in case of SDS. This could be due to high critical micelles SDS concentration comparing with others which is attributed to the adsorption anionic nature of this surfactant. Both FTIR and UV-vis spectra show a red shift in the presence of SDS and blue shift in the presence of CTAB and OGM. The blue shift in the absorption edge indicates the quantum confinement property of nanoparticles. The zinc peroxide nanoparticles prepared in additives-free media was also characterized by Raman spectra which show the characteristic peaks at 830-840 and 420-440 cm{sup -1}.

  12. Structural, Hirshfeld surface and spectroscopic studies of the noncentrosymmetric 1-ethylpiperazinediium pentachloroantimonate (III) monohydrate

    Science.gov (United States)

    Soudani, S.; Zeller, M.; Jelsch, C.; Lefebvre, F.; Ben Nasr, Cherif

    2016-08-01

    1-Ethylpiperazinediium pentachloroantimonate (III) monohydrate, C6H16N2SbCl5·H2O, has been synthesized by the reaction of antimony trioxide (Sb2O3) and 1-ethylpiperazine in an aqueous solution of hydrochloric acid. The structure crystallizes in orthorhombic system, in the non-centrosymmetric space group Pca21 and consists of isolated [C6H16N2]2+ cations, square pyramidal [SbCl5]2- anions and lattice water molecules. Osbnd H⋯Cl hydrogen bonds link the [SbCl5]2- anions and water molecules to form double chains stretching along the [101] direction. The chains in turn are linked to the organic cations via Nsbnd H⋯Cl, Csbnd H⋯Cl, Csbnd H⋯O and Nsbnd H⋯O hydrogen bonds to form a three-dimensional network. This structure presents an example of a general square pyramidal complex ion containing a stereo-chemically active lone pair of electrons. Solid state 13C and 15N CP-MAS NMR spectra are in agreement with the X-ray structure, and vibrational absorption bands were identified by infrared spectroscopy. DFT calculations allowed the attribution of the NMR peaks and IR absorption bands. The interactions variability of the two independent cations and ten chloride atoms is analyzed via Hirshfeld surface analysis.

  13. Spectroscopic study of binding of chlorogenic acid with the surface of ZnO nanoparticles

    Science.gov (United States)

    Belay, Abebe; Kim, Hyung Kook; Hwang, Yoon-Hwae

    2017-09-01

    Understanding the interaction properties of biological materials with ZnO NPs is fundamental interest in the field of biotechnological applications as well as in the formation of optoelectronic devices. In this research, the binding of ZnO NPs and chlorogenic acid (CGA) were investigated using fluorescence quenching, UV-Vis absorption spectroscopy, Fourier transform infrared (FTIR), Raman spectroscopy, scanning electron microscopy (TEM), and dynamic light scattering (DLS) techniques. The study results indicated the fluorescence quenching between ZnO NPs and CGA rationalized in terms of static quenching mechanism or the formation of nonfluorescent CGA-ZnO. From fluorescence quenching spectral analysis the binding constant ( K a ), number of binding sites ( n), and thermodynamic properties, were determined. The quenching constants ( K sv) and binding constant ( K a ), decrease with increasing the temperature and their binding sites n are 2. The thermodynamic parameters determined using Van't Hoff equation indicated binding occurs spontaneously involving the hydrogen bond and van der Walls forces played the major role in the reaction of ZnO NPs with CGA. The Raman, SEM, DLS, and Zeta potential measurements were also indicated the differences in the structure, morphology and sizes of CGA, ZnO NPs, and their corresponding CGA-ZnO due to adsorption of CGA on the surface of ZnO NPs

  14. Green preparation and spectroscopic characterization of plasmonic silver nanoparticles using fruits as reducing agents

    DEFF Research Database (Denmark)

    Hyllested, Jes Ærøe; Espina Palanco, Marta; Hagen, Nicolai

    2015-01-01

    Chemicals typically available in plants have the capability to reduce silver and gold salts and to create silver and gold nanoparticles. We report the preparation of silver nanoparticles with sizes between 10 and 300 nm from silver nitrate using fruit extract collected from pineapples and oranges...... microscopy shows that the shapes of the nanoparticles are different depending on the fruit used for preparation. The green preparation process results mainly in individual nanoparticles with a very poor tendency to form aggregates with narrow gaps even when aggregation is forced by the addition of Na...... absorption correlates with the decrease of absorption band in the UV. This confirms the evolution of silver nanoparticles from silver clusters. The presence of various silver clusters on the surface of the “green” plasmonic silver nanoparticles is also supported by a strong multi-color luminesce signal...

  15. Fractal characterization and wettability of ion treated silicon surfaces

    Science.gov (United States)

    Yadav, R. P.; Kumar, Tanuj; Baranwal, V.; Vandana, Kumar, Manvendra; Priya, P. K.; Pandey, S. N.; Mittal, A. K.

    2017-02-01

    Fractal characterization of surface morphology can be useful as a tool for tailoring the wetting properties of solid surfaces. In this work, rippled surfaces of Si (100) are grown using 200 keV Ar+ ion beam irradiation at different ion doses. Relationship between fractal and wetting properties of these surfaces are explored. The height-height correlation function extracted from atomic force microscopic images, demonstrates an increase in roughness exponent with an increase in ion doses. A steep variation in contact angle values is found for low fractal dimensions. Roughness exponent and fractal dimensions are found correlated with the static water contact angle measurement. It is observed that after a crossover of the roughness exponent, the surface morphology has a rippled structure. Larger values of interface width indicate the larger ripples on the surface. The contact angle of water drops on such surfaces is observed to be lowest. Autocorrelation function is used for the measurement of ripple wavelength.

  16. Characterization of defects in ZnO nanocrystals: Photoluminescence and positron annihilation spectroscopic studies

    Science.gov (United States)

    Mishra, A. K.; Chaudhuri, S. K.; Mukherjee, S.; Priyam, A.; Saha, A.; Das, D.

    2007-11-01

    Defects present in ZnO nanocrystals prepared by a wet chemical method have been characterized by photoluminescence (PL) and positron annihilation spectroscopy (PAS) techniques. The as-prepared sample was heat treated at different temperatures to obtain nanocrystals in the size range of 19-39nm. X ray diffractograms confirmed the single-phase wurtzite structure formation. Photoluminescence measurements showed a strong violet band at 434nm, which has been identified as due to electronic transitions from the zinc interstitial defect level to the top of the valence band. A marked decrease in the intensity of the violet emission with increasing heat-treatment temperature has been observed, which is attributed to recombination of zinc interstitials with zinc vacancies. Positron annihilation spectroscopy has been employed to understand the dynamics of the vacancy-type defects and their annealing behavior. The observed variation of the defect related lifetime components with heat-treatment temperature has been successfully explained by using a three-state trapping model. The results of PL and PAS studies in the present case are found to be complementary to each other.

  17. Structural and spectroscopic characterization of isotypic sodium, rubidium and cesium acesulfamates

    Energy Technology Data Exchange (ETDEWEB)

    Piro, Oscar E.; Echeverria, Gustavo A. [Universidad Nacional de La Plata (Argentina). Dept. de Fisica y Inst. IFLP (CONICET); Castellano, Eduardo E. [Universidade de Sao Paulo, Sao Carlos (Brazil). Inst. de Fisica; Parajon-Costa, Beatriz S.; Baran, Enrique J. [Universidad Nacional de La Plata (Argentina). Centro de Quimica Inorganica (CEQUINOR, CONICET/UNLP)

    2015-11-01

    Three new acesulfamate salts, NaC{sub 4}H{sub 4}NO{sub 4}S, RbC{sub 4}H{sub 4}NO{sub 4}S and CsC{sub 4}H{sub 4}NO{sub 4}S, were prepared by reactions in aqueous solutions and thoroughly characterized. Their crystal and molecular structures were determined by single crystal X-ray diffraction methods. They crystallize in the monoclinic space group P2{sub 1}/a with a = 7.2518(2), b = 8.9414(4), c = 10.5929(4) Aa, β = 99.951(3) , V = 676.52(4) Aa{sup 3} for the Na salt; a = 7.4663(3), b = 9.6962(4), c = 10.4391(4) Aa, β = 95.150(3) , V = 752.68(5) Aa{sup 3} for the Rb salt and a = 7.5995(4), b = 9.9439(4), c = 10.8814(6) Aa, β = 91.298(5) , V = 822.08(7) Aa{sup 3} for the Cs salt, and Z = 4 molecules per unit cell. The three compounds are isotypic to each other and to the previously reported potassium salt. The metal ions are in irregular polyhedral coordination with six neighboring acesulfamate anions through their nitrogen and carbonyl and sulfoxide oxygen atoms. The FTIR spectra of the compounds were also recorded and are briefly discussed.

  18. Efficient MW-Assisted Synthesis, Spectroscopic Characterization, X-ray and Antioxidant Properties of Indazole Derivatives

    Directory of Open Access Journals (Sweden)

    Efrain Polo

    2016-07-01

    Full Text Available A small series of tetrahydroindazoles was prepared, starting from 2-acetylcyclohexanone and different hydrazines using reflux and a focused microwave reactor. Microwave irradiation (MW favored the formation of the desired products with improved yields and shortened reaction times. This is a simple and green method for the synthesis of substituted tetrahydroindazole derivatives. The in vitro antioxidant activity was evaluated using the DPPH and ABTS methods. In these assays, 2-(4-fluorophenyl-3-methyl-4,5,6,7-tetrahydro-2H-indazole (3f showed moderate DPPH decoloring activity, while 3-methyl-4,5,6,7-tetrahydro-1H-indazole (3a, 3-methyl-2-phenyl-4,5,6,7-tetrahydro-2H-indazole (3b and 2-(4-fluorophenyl-3-methyl-4,5,6,7-tetrahydro-2H-indazole (3f were the most active in the ABTS assay. All compounds were well characterized by IR, 1H-, 13C-NMR and GC-MS spectroscopy and physical data, while the structure of 4-(3-methyl-4,5,6,7-tetrahydro-2H-indazol-2-ylbenzoic acid (3e was also determined by single crystal X-ray analysis.

  19. Isolation and spectroscopic characterization of the structural subunits of keyhole limpet hemocyanin.

    Science.gov (United States)

    Schütz, J; Dolashka-Angelova, P; Abrashev, R; Nicolov, P; Voelter, W

    2001-04-07

    Keyhole limpet hemocyanin is a respiratory glycoprotein of high molecular weight from the gastropod mollusc Megathura crenulata. Two subunits, KLH1 and KLH2, were isolated using ion exchange chromatography and their physical properties are compared with the parent molecule. The various proteins are characterized by fluorescence spectroscopy, combined with fluorescence quenching studies, using acrylamide, cesium chloride and potassium iodide as tryptophan quenchers. The conformational stability of the native aggregate and its isolated structural subunits are also studied by circular dichroism and fluorescence spectroscopy as a function of temperature, as well as in the presence of guanidinium hydrochloride and urea. The associated subunits in the hemocyanin aggregates increase considerably the melting temperature to 67 degrees C and the free energy of stabilization in water, DeltaG(H(2)O)(D), towards guanidinium hydrochloride is higher for the decamer as compared to the isolated subunits; this difference can be accounted for by the stabilizing effects of intra-subunit interactions exerted within the oligomer. The copper-dioxygen complex at the active site additionally stabilizes the molecule, and removing of the copper ions increases the tryptophan emission and the quantum yield of the fluorescence.

  20. Functionalized tellurols: synthesis, spectroscopic characterization by photoelectron spectroscopy, and quantum chemical study.

    Science.gov (United States)

    Khater, Brahim; Guillemin, Jean-Claude; Bajor, Gábor; Veszprémi, Tamás

    2008-03-03

    Ethene-, cyclopropane-, 3-butene-, and cyclopropanemethanetellurol have been synthesized by reaction of tributyltin hydride with the corresponding ditellurides and characterized by 1H, 13C, and 125Te NMR spectroscopy and high-resolution mass spectrometry. The tellurols of this series, with a gradually increasing distance between the tellurium atom and the unsaturated group, have been studied by photoelectron spectroscopy and quantum chemical calculations. Two stable conformations of ethenetellurol and cyclopropanetellurol, five of allyltellurol, and four of cyclopropanemethanetellurol were found. In the photoelectron spectrum of vinyltellurol, the huge split between the first two bands indicates a direct interaction between the tellurium lone electron pair and the double bond. In the allyl derivative, a hyperconjugation effect was found for the most stable conformers. In contrast to the vinyl compounds, no direct interaction between the lone electron pair of X (X = O, S, Se, and Te) and the three-membered ring could be observed in the cyclopropyl derivatives. A hyperconjugation-like effect, which is independent of the relative orientation of the X-H group, is found to increase from S to Te. Thus, the type and extent of the interaction between the TeH group and an unsaturated or cyclopropyl moiety are clarified while the first comparison of interactions between the nonradioactive unsaturated chalcogen derivatives is performed.

  1. Spectroscopic and Thermal Characterization of Gliclazide, Glibenclamide and Glimeperide Complexes with Transition and Inner Transition Metals

    Directory of Open Access Journals (Sweden)

    MOHAMMAD TAWKIR

    2012-12-01

    Full Text Available Metal complxes of Gliclazide, Glibenclamide and Glimeperide drugs were prepared and characterized based on elemental analysis, FT-IR, Molar conductance and thermal analysis (TGA and DTG technique. From elemental analysis data, the complexes were proposed to have general formulae (GLZ2Co2H2O, (GLZ2Cu, (GLB2Co2H2O, Cu(GLB 2, (GLM 2Hg and (GLM 2La2H2O. The molar conductance data reveal that all the metal complexes are non-electrolytic, IR spectra shows that GLZ, GLB and GLM are coordinated to metal ions in a neutral bidentate manner from the ESR spectra and XRD-spectra. It is found that the geometrical structures of these complexes are tetrahedral Cu(II ,Hg(II and octrahedral Co(II, La(II. The thermal behavior of these complexes studied using thermogravimetric analysis (TGA and DTG techniques. The results obtained shows that the hydrated complexes lose water molecules of hydration followed immediately by decomposition of the anions and ligand molecules in the successive unseparate steps. Thermogravimetric analysis was carried out to study the decomposition and various kinetic parameters. Freeman Carroll and Sharp Wentworth method have been applied for calculation of kinetic parameters. While data from freeman Carroll method have been used to determine various thermodynamic parameters such as order of reactions, energy of activation, frequency factor, entropy change, free energy change and apparent entropy change and order of reaction..

  2. Syntheses, crystal structure, spectroscopic characterization and antifungal activity of new N-R-sulfonyldithiocarbimate metal complexes.

    Science.gov (United States)

    Alves, Leandro C; Rubinger, Mayura M M; Lindemann, Renata H; Perpétuo, Genivaldo J; Janczak, Jan; Miranda, Liany D L; Zambolim, Laércio; Oliveira, Marcelo R L

    2009-07-01

    Five new compounds with the general formula of (Bu(4)N)(2)[M(RSO(2)NCS(2))(2)], where Bu(4)N=tetrabutylammonium cation, (M=Ni, R=4-FC(6)H(4)) (1), (M=Zn, R=4-FC(6)H(4), 4-ClC(6)H(4), 4-BrC(6)H(4), 4-IC(6)H(4)), (2), (3), (4) and (5), respectively, were obtained by the reaction of the appropriate potassium N-R-sulfonyldithiocarbimate (RSO(2)N=CS(2)K(2)) with nickel(II) chloride hexahydrate or zinc(II) acetate dihydrate in metanol:water 1:1. The elemental analyses and the IR data are consistent with the formation of the expected bis(dithiocarbimato)metal(II) complexes. The (1)H and (13)C NMR spectra showed the signals for the tetrabutylammonium cation and the dithiocarbimate moieties. The compounds 1, 2 and 5 were also characterized by X-ray diffraction techniques. The nickel(II) is coordinated by two N-4-fluorophenylsulphonyldithiocarbimato(2-) ligands forming a planar coordination. The zinc(II) exhibits distorted tetrahedral configuration in compounds 2 and 5 due to the chelation effect of two sulfur atoms of the N-R-sulfonyldithiocarbimate ligands. The antifungal activities of the compounds were tested in vitro against Colletotrichum gloeosporioides, an important fungus that causes the plant disease known as anthracnose in fruit trees. All the complexes were active.

  3. Spectroscopic, Structural, and Computational Characterization of Three Bispidinone Derivatives, as Ligands for Enantioselective Metal Catalyzed Reactions.

    Science.gov (United States)

    Castellano, Carlo; Sacchetti, Alessandro; Meneghetti, Fiorella

    2016-04-01

    Three chiral derivatives of the alkaloid sparteine (bispidines), characterized by the 3,7-diazabicyclo[3.3.1]nonane moiety, were designed as efficient ligands in a number of enantioselective reactions due to their metal coordination properties. A full evaluation of the 3D properties of the compounds was carried out, as the geometrical features of the bicyclic framework are strictly related to the efficiency of the ligands in the asymmetric catalysis. The selected molecules have different molecular complexity for investigating the effects of different chiral groups on the bicycle conformation. We report here a thorough analysis of their molecular arrangement, by NMR spectroscopy, single crystal X-ray crystallography, and computational techniques, which put in evidence their conformational preferences and the parameters needed for the design of more efficient ligands in asymmetric synthetic routes. The results confirmed the high molecular flexibility of the compounds, and indicated how to achieve a control of the chair-chair/boat-chair conformational ratio, by adjusting the relative size of the substituents on the piperidine nitrogens.

  4. Synthesis, spectroscopic characterization and thermogravimetric analysis of two series of substituted (metallo)tetraphenylporphyrins

    Science.gov (United States)

    Al-Shewiki, Rasha K; Mende, Carola; Buschbeck, Roy; Siles, Pablo F; Schmidt, Oliver G; Lang, Heinrich

    2017-01-01

    Subsequent treatment of H2TPP(CO2H)4 (tetra(p-carboxylic acid phenyl)porphyrin, 1) with an excess of oxalyl chloride and HNR2 afforded H2TPP(C(O)NR2)4 (R = Me, 2; iPr, 3) with yields exceeding 80%. The porphyrins 2 and 3 could be converted to the corresponding metalloporphyrins MTPP(C(O)NR2)4 (R = Me/iPr for M = Zn (2a, 3a); Cu (2b, 3b); Ni (2c, 3c); Co (2d, 3d)) by the addition of 3 equiv of anhydrous MCl2 (M = Zn, Cu, Ni, Co) to dimethylformamide solutions of 2 and 3 at elevated temperatures. Metalloporphyrins 2a–d and 3a–d were obtained in yields exceeding 60% and have been, as well as 2 and 3, characterized by elemental analysis, electrospray ionization mass spectrometry (ESIMS) and IR and UV–vis spectroscopy. Porphyrins 2, 2a–d and 3, 3a–d are not suitable for organic molecular beam deposition (OMBD), which is attributed to their comparatively low thermal stability as determined by thermogravimetric analysis (TG) of selected representatives. PMID:28685120

  5. Efficient MW-Assisted Synthesis, Spectroscopic Characterization, X-ray and Antioxidant Properties of Indazole Derivatives.

    Science.gov (United States)

    Polo, Efrain; Trilleras, Jorge; Ramos, Juan; Galdámez, Antonio; Quiroga, Jairo; Gutierrez, Margarita

    2016-07-09

    A small series of tetrahydroindazoles was prepared, starting from 2-acetylcyclohexanone and different hydrazines using reflux and a focused microwave reactor. Microwave irradiation (MW) favored the formation of the desired products with improved yields and shortened reaction times. This is a simple and green method for the synthesis of substituted tetrahydroindazole derivatives. The in vitro antioxidant activity was evaluated using the DPPH and ABTS methods. In these assays, 2-(4-fluorophenyl)-3-methyl-4,5,6,7-tetrahydro-2H-indazole (3f) showed moderate DPPH decoloring activity, while 3-methyl-4,5,6,7-tetrahydro-1H-indazole (3a), 3-methyl-2-phenyl-4,5,6,7-tetrahydro-2H-indazole (3b) and 2-(4-fluorophenyl)-3-methyl-4,5,6,7-tetrahydro-2H-indazole (3f) were the most active in the ABTS assay. All compounds were well characterized by IR, ¹H-, (13)C-NMR and GC-MS spectroscopy and physical data, while the structure of 4-(3-methyl-4,5,6,7-tetrahydro-2H-indazol-2-yl)benzoic acid (3e) was also determined by single crystal X-ray analysis.

  6. Infrared Spectroscopic, X-ray and Nanoscale Characterization of Strontium Titanate Thin Films

    Energy Technology Data Exchange (ETDEWEB)

    Webb, J. D.; Moutinho, H. R.; Kazmerski, L. L.; Mueller, C. H.; Rivkin, T. V.; Treece, R. E.; Dalberth, M.; Rogers, C. T.

    1997-01-01

    Attenuated total reflectance (ATR) measurements were performed using Fourier transform infrared (FTIR) spectroscopy in the ATR mode with a thallium iodobromide (KRS-5) crystal to measure the frequencies of the v{sub 3} and v{sub 4} phonon absorption bands in thin strontium titanate films deposited on single-crystal yttrium-barium copper oxide (YBCO), lanthanum aluminate, magnesium oxide, and strontium titanate substrates. The KRS-5 crystal enabled FTIR-ATR measurements to be made at frequencies above 400 cm-1. Atomic force microscopy (AFM) and X-ray diffraction (XRD) measurements were also made to further characterize the films. The measurements were repeated on single-crystal specimens of strontium titanate and the substrates for comparison. Softening in the frequency of the v{sub 4} transverse optical phonon in the lattice-mismatched films below the established value of 544 cm-1 is indicative of the highly textured, polycrystalline ceramic nature of the films and is consistent with the XRD and AFM results.

  7. Infrared spectroscopic, x-ray, and nanoscale characterization of strontium titanate thin films

    Energy Technology Data Exchange (ETDEWEB)

    Webb, J D; Moutinho, H R; Kazmerski, L L [National Renewable Energy Lab., Golden, CO (United States); Mueller, C H; Rivkin, T V; Treece, R E [Superconducting Core Technologies, Inc., Golden, CO (United States); Dalberth, M; Rogers, C T [Colorado Univ., Boulder, CO (United States). Dept. of Physics

    1996-06-01

    Attenuated total reflectance (ATR) measurements were performed using Fourier transform infrared (FTIR) spectroscopy in the ATR mode with a thallium iodobromide (KRS-5) crystal to measure the frequencies of the v{sub 3} and v{sub 4} phonon absorption bands in thin Sr titanate films deposited on single-crystal Y-Ba Cu oxide (YBCO), La aluminate, Mg oxide, and Sr titanate substrates. The KRS-5 crystal enabled FTIR-ATR measurements at frequencies above 400 cm{sup -1}. Atomic force microscopy (AFM) and x-ray diffraction (XRD) measurements were also made to further characterize the films. The measurements were repeated on single-crystal specimens of Sr titanate and the substrates for comparison. Softening in the frequency of the v{sub 4} transverse optical phonon in the lattice-mismatched films below the established value of 544 cm{sup -1} is indicative of the highly textured, polycrystalline ceramic nature of the films and is consistent with the XRD and AFM results.

  8. Infrared spectroscopic, x-ray, and nanoscale characterization of strontium titanate thin films

    Energy Technology Data Exchange (ETDEWEB)

    Webb, J.D.; Moutinho, H.R.; Kazmerski, L.L. [National Renewable Energy Lab., Golden, CO (United States); Mueller, C.H.; Rivkin, T.V.; Treece, R.E. [Superconducting Core Technologies, Inc., Golden, CO (United States); Dalberth, M.; Rogers, C.T. [Colorado Univ., Boulder, CO (United States). Dept. of Physics

    1996-04-01

    Attenuated total reflectance (ATR) measurements were performed using Fourier transform infrared (FTIR) spectroscopy in the ATR mode with a thallium iodobromide (KRS-5) crystal to measure the frequencies of the {nu}{sub 3} and {nu}{sub 4} phonon absorption bands in thin strontium titanate films deposited on single-crystal yttrium-barium copper oxide (YBCO), lanthanum aluminate, magnesium oxide, and strontium titanate substrates. The KRS-5 crystal enabled FTIR-ATR measurements to be made at frequencies above 400 cm{sup {minus}1}. Atomic force microscopy (AFM) and X-ray diffraction (XRD) measurements were also made to further characterize the films. The measurements were repeated on single-crystal specimens of strontium titanate and the substrates for comparison. Softening in the frequency of the {nu}{sub 4} transverse optical phonon in the lattice- mismatched films below the established value of 544 cm{sup {minus}1} is indicative of the highly textured, polycrystalline ceramic nature of the films and is consistent with the XRD and AFM results.

  9. Crystal structure, spectroscopic characterization and antibacterial activities of a silver complex with sulfameter

    Science.gov (United States)

    Nakahata, Douglas H.; Lustri, Wilton R.; Cuin, Alexandre; Corbi, Pedro P.

    2016-12-01

    A silver complex with the sulfonamide sulfameter, also known as sulfamethoxydiazine (SMTR), was prepared and characterized. Chemical analyses were consistent with the [Ag(C11H11N4O3S)] composition (AgSMTR), while conductivity measurements in DMSO indicated a non-electrolyte behavior of the complex in this solvent. High-resolution ESI(+)-QTOF mass spectrometric experiments revealed the presence of the [Ag(C11H11N4O3S)+H]+ and [Ag2(C11H11N4O3S)2+H]+ species in solution. Infrared and NMR spectroscopies indicated coordination of the ligand to the metal by the nitrogen atoms of the sulfonamide group and of the pyrimidine ring. The structure of AgSMTR was solved by powder X-ray diffraction technique using the Rietveld method. The solved structure confirms the formation of a dimer, where each silver ion is coordinated by one of the nitrogen atoms of the pyrimidine ring, the nitrogen of the sulfonamide group and by an oxygen atom from the sulfonyl group. An argentophilic interaction of 2.901(1) Å is present in this dimeric structure. The AgSMTR complex was assayed over Gram-positive (Staphylococcus aureus) and Gram-negative (Pseudomonas aeruginosa and Escherichia coli) bacterial strains, and it was found that the compound is 8 times more active over the Gram-negative bacteria in DMSO solution, with MIC values in the micromolar range.

  10. Lipoxygenase isoenzymes: a spectroscopic and structural characterization of soybean seed enzymes.

    Science.gov (United States)

    Draheim, J E; Carroll, R T; McNemar, T B; Dunham, W R; Sands, R H; Funk, M O

    1989-02-15

    Applying recent developments in protein purification techniques, a number of lipoxygenase isoenzymes have been isolated in satisfactory quantities for a detailed physical and structural characterization. Four seed isoenzymes from two soybean cultivars have been studied by peptide mapping, free thiol and iron content determinations, and C-terminal analysis as well as by uv-visible absorption and EPR spectroscopy. While differences between the type 1 enzyme and the other isoenzymes were readily detected using proteolytic peptide mapping, digestion with dilute hydrochloric acid and C-terminal analysis both revealed structural features which were similar in all of the isoenzymes. One clear difference between the lipoxygenases was in their free sulfhydryl group content. The uv-visible absorption spectrum of each native isoenzyme was consistent with expectations for the experimental aromatic amino acid content. All of the isoenzymes contained one non-heme iron atom per molecule of protein. The oxidation of each isoenzyme with product hydroperoxide resulted in the conversion of the iron from an EPR silent state into several forms with EPR signals characteristic of high spin iron(III). The EPR spectra of all isoenzymes were remarkably similar. A time course EPR and catalytic activity study revealed that the various EPR active states represent a complex equilibrium between iron atoms in different environments. The pH dependence for the EPR and absorption spectroscopy lends support to the hypothesis that acid/base chemistry represents an important aspect of lipoxygenase catalysis.

  11. Chemical and spectroscopical characterization of humic acids from two south Brazilian coals of different ranks

    Energy Technology Data Exchange (ETDEWEB)

    Dick, D.P.; Mangrich, A.S.; Menezes, S.M.C.; Pereira, B.F. [UFRGS, Porto Alegre (Brazil)

    2002-07-01

    Humic acids (HA) extracted from two coals of different ranks, from their regenerated samples and from a nitrated sample, were characterized by elemental analysis and by infra-red (FTIR), solid state C-13 nuclear magnetic resonance (NMR) and electronic paramagnetic resonance (EPR) spectroscopies. The low rank coal HA presented higher C and lower O contents, higher C/N and lower H/C and O/C ratios than high rank coal HA. NMR results showed that both samples were more aromatic and less carboxylic than common soil HA. Those characteristics may limit the coal HA efficiency as an appropriate soil conditioner and fertilizer. The regeneration process did not produce major alterations in the coal HA, except a decrease of the free radical content as determined by EPR spectroscopy. Probably, the regeneration conditions and time were not adequate to oxidize the samples. The obtained FTIR spectra were much alike, except that from the nitrated sample, where the absorption band at 1533 cm{sup -1} confirms the presence of nitrated groups. The nitration process increased the N content and reduced the C/N ratio to values comparable to those reported for soil HA, but the aromaticity still remained high and the carboxylic content was lowered after the procedure. 27 refs., 2 figs., 3 tabs.

  12. Chemical and Spectroscopical Characterization of Humic Acids from two South Brazilian Coals of Different Ranks

    Directory of Open Access Journals (Sweden)

    Dick Deborah P.

    2002-01-01

    Full Text Available Humic acids (HA extracted from two coals of different ranks, from their regenerated samples and from a nitrated sample, were characterized by elemental analysis and by infra-red (FTIR, solid state 13C nuclear magnetic resonance (NMR and eletronic paramagnetic resonance (EPR spectroscopies. The low rank coal HA presented higher C and lower O contents, higher C/N and lower H/C and O/C ratios than high rank coal HA. NMR results showed that both samples were more aromatic and less carboxylic than common soil HA. Those characteristics may limit the coal HA efficiency as an appropriate soil conditioner and fertilizer. The regeneration process did not produce major alterations in the coal HA, except a decrease of the free radical content as determined by EPR spectroscopy. Probably, the regeneration conditions and time were not adequate to oxidize the samples. The obtained FTIR spectra were much alike, except that from the nitrated sample, where the absorption band at 1533 cm-1 confirms the presence of nitrated groups. The nitration process increased the N content and reduced the C/N ratio to values comparable to those reported for soil HA, but the aromaticity still remained high and the carboxylic content was lowered after the procedure.

  13. NMR-spectroscopic characterization of phosphodiester bond cleavage catalyzed by the minimal hammerhead ribozyme.

    Science.gov (United States)

    Fürtig, Boris; Richter, Christian; Schell, Peter; Wenter, Philipp; Pitsch, Stefan; Schwalbe, Harald

    2008-01-01

    In order to relate the conformational dynamics of the hammerhead ribozyme to its biological function the cleavage reaction catalyzed by the hammerhead ribozyme was monitored by time-resolved nuclear magnetic resonance (NMR) spectroscopy. For this purpose, the two nucleosides around the scissile phosphodiester bond were selectively (13)C labelled in multi-step organic syntheses starting from uniformly (13)C-labelled glucose. The phosphoamidites were incorporated using phosphoamidite chemistry in the hammerhead substrate strand. In addition, the 2'-OH group on the 5'-side of the hammerhead substrate strand was labelled with a photolabile protecting group. This labelling strategy enabled a detailed characterisation of the nucleotides around the scissile phosphodiester bond in the ground state conformation of the hammerhead ribozyme in the absence and presence of Mg(2+) ions as well as of the product state. Photochemical induction of the reaction in situ was further characterized by time-resolved NMR spectroscopy. The detailed structural and dynamic investigations revealed that the conformation of the hammerhead ribozyme is significantly affected by addition of Mg(2+) leading to an ensemble of conformations where dynamic transitions between energetically similar conformations occur on the ms-timescale in the presence of Mg(2+). The dynamic transitions are localized around the catalytic core. Cleavage from this ensemble cannot be described by mono-exponential kinetics but follows bi-exponential kinetics. A model is described to take into account these experimental data.

  14. Synthesis, characterization and spectroscopic investigation of Cr3+ doped wollastonite nanophosphor

    Science.gov (United States)

    Madesh Kumar, M.; Nagabhushana, H.; Nagabhushana, B. M.; Suriyamurthy, N.; Sharma, S. C.; Shivakumara, C.; Hari Krishna, R.

    2014-07-01

    This work explores the preparation of nanocrystalline Cr3+ (1-5 mol%) doped CaSiO3 phosphors by solution combustion process and study of its photoluminescence (PL) behavior. The nanopowders are well characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform infra-red (FTIR) spectroscopy. PXRD results confirm monoclinic phase upon calcination at 950 °C for 3 h. SEM micrographs indicates that the powder is highly porous and agglomerated. The TEM images show the powder to consist of spherical shaped particles of size ∼30-60 nm. Upon 323 nm excitation, the emission profile of CaSiO3:Cr3+ exhibits a narrow red emission peak at 641 nm due to 2E → 4A2 transition and broad band at 722 nm due to 4T2g → 4A2g. It is observed that PL intensity increases with increase in Cr3+ concentration and highest PL intensity is observed for 3 mol% doped sample. The PL intensity decreases with further increase in Cr3+ doping. This decrease in PL intensity beyond 3 mol% is ascribed to concentration quenching. Racah parameters are calculated to describe the effects of electron-electron repulsion within the crystal lattice. The parameters show 21% reduction in the Racah parameter of free ion and the complex, indicating the moderate nephelauxetic effect in the lattice.

  15. Metal complexes of N'-(2-hydroxy-5-phenyldiazenyl benzylideneisonicotinohydrazide: Synthesis, spectroscopic characterization and antimicrobial activity

    Directory of Open Access Journals (Sweden)

    El-Tabl Abdou S.

    2013-01-01

    Full Text Available A new series of Cu(II, Ni(II, Co(II, Mn(II, Zn(II, Cd(II, Hg(II , VO(II, UO2(II , Fe(III and Ru(III complexes of N'-(2-hydroxy-5- phenyldiazenylbenzylideneisonicotinohydrazide(H2L have been synthesized and characterized by elemental,1H-NMR, IR, UV-Vis., ESR, magnetic, thermogravimetric analyses(TG and conductivity measurements. The spectral data show that, the ligand behaves as a neutral bidentate, (2, (4, (5, (6 and (14, monobasic bidentate, (3, (7, (8, (9 and (10, monobasic tridentate (11 and (16 or dibasic tridentate (12, (13 and (15 bonded to metal ions via the carbonyl oxygen atom in ketonic or enolic form, azomethine nitrogen atom and/or deprotonated phenolic hydroxyl oxygen. The ESR spectrum of solid vanadyl(II, complex (2 shows axially anisotropic spectrum with eight lines in the low field region and g?>g||, A||>>A?relationship, which is characteristics of distorted octahedral structure with dxy ground state. However, copper(II complexes (4, (5 and (6 and manganese(II complex (10 show an isotropic type while the copper(II complexes (3 and (7show an axial symmetry type with g||>g?>ge indicating a covalent bond character. The antibacterial and antifungal activities of the ligand and its metal complexes show mild activity compared with standard drugs (Tetracycline for bacteria and amphotricene B for fungi.

  16. New copper(II) complexes with dopamine hydrochloride and vanillymandelic acid: Spectroscopic and thermal characterization

    Science.gov (United States)

    Mohamed, Gehad G.; Nour El-Dien, F. A.; El-Nahas, R. G.

    2011-10-01

    The dopamine derivatives participate in the regulation of wide variety of physiological functions in the human body and in medication life. Increase and/or decrease in the concentration of dopamine in human body reflect an indication for diseases such as Schizophrenia and/or Parkinson diseases. The Cu(II) chelates with coupled products of dopamine hydrochloride (DO.HCl) and vanillymandelic acid (VMA) with 4-aminoantipyrine (4-AAP) are prepared and characterized. Different physico-chemical techniques namely IR, magnetic and UV-vis spectra are used to investigate the structure of these chelates. Cu(II) forms 1:1 (Cu:DO) and 1:2 (Cu:VMA) chelates. DO behave as a uninegative tridentate ligand in binding to the Cu(II) ion while VMA behaves as a uninegative bidentate ligand. IR spectra show that the DO is coordinated to the Cu(II) ion in a tridentate manner with ONO donor sites of the phenolic- OH, -NH and carbonyl- O, while VMA is coordinated with OO donor sites of the phenolic- OH and -NH. Magnetic moment measurements reveal the presence of Cu(II) chelates in octahedral and square planar geometries with DO and VMA, respectively. The thermal decomposition of Cu(II) complexes is studied using thermogravimetric (TG) and differential thermal analysis (DTA) techniques. The activation thermodynamic parameters, such as, energy of activation, enthalpy, entropy and free energy change of the complexes are evaluated and the relative thermal stability of the complexes are discussed.

  17. Surface Characterization: what has been done , what has been learnt?

    Energy Technology Data Exchange (ETDEWEB)

    Peter Kneisel

    2003-09-01

    Electromagnetic fields penetrate only a distance of {approx} 60 nm into the surface of a superconductor such as niobium. Therefore it is obvious that the condition of a cavity surface will affect the performance of this cavity. In at least the last 30 years niobium surfaces as used in superconducting accelerating cavities have been investigated by surface characterization techniques such as scanning electron microscopy (SEM), Auger spectroscopy (AES), X-ray photon spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDX), electron spectroscopy for chemical analysis (ESCA) and secondary ion mass spectrometry (SIMS). The objective of all these investigations was to establish correlations between surface conditions and cavity performances such as surface resistance and accelerating gradients. Much emphasis was placed on investigating surface topography and the oxidation states of niobium under varying conditions such as buffered chemical polishing, electropolishing, oxipolishing, high temperature heat treatment, post-purification heat treatment and in-situ baking. Additional measurements were conducted to characterize the behavior of a niobium surface more relevant to rf cavities such as resonant (multipacting) and non-resonant (field emission) electron loading. A large amount of knowledge has been extracted by all these investigations; nevertheless, there is still a lack of reproducibility in cavity performance when applying the ''best'' process to a cavity surface and no clear correlation has been established between niobium surface features and cavity performance. This contribution gives a review of the attempts to characterize niobium surfaces over the last three decades and tries to extract the ''white spots'' in our knowledge.

  18. Humic acid from Shilajit – a physico-chemical and spectroscopic characterization

    Directory of Open Access Journals (Sweden)

    SURAJ P. AGARWAL

    2010-03-01

    Full Text Available Shilajit is a blackish–brown exudation, consisting of organic substances, metal ions and minerals, from different formations, commonly found in the Himalayan region (1000–3000 m from Nepal to Kashmir. Shilajit can also be collected throughout the mountain regions in Afghanistan, Bhutan, China, Bajkal, throughout Ural, Caucasus and Altai mountains also, at altitudes between 1000 to 5000 m. The major physiological action of shilajit has been attributed to the presence of bioactive dibenzo-α-pyrones together with humic and fulvic acids, which act as carrier molecules for the active ingredients. In this work, the aim was to extract humic acid from Shilajit from various sources and characterised these humic acids based on their physicochemical properties, elemental analysis, UV/Vis and FTIR spectra, X-ray diffraction pattern and DSC thermograms. The spectral features obtained from UV/Vis, FTIR, XRD and DSC studies for samples of different origins showed a distinct similarity amongst themselves and in comparison to soil humic acids. The surfactant properties of the extracted fulvic acids were investigated by determining the effect of increasing concentration on the surface tension of water. The study demonstrated that humic acids extracted from shilajit indeed possessed surfactant properties.

  19. Characterizing infantile hemangiomas with a near-infrared spectroscopic handheld wireless device

    Science.gov (United States)

    Fong, Christopher J.; Hoi, Jennifer W.; Kim, Hyun K.; Behr, Gerald; Geller, Lauren; Antonov, Nina; Flexman, Molly; Garzon, Maria; Hielscher, Andreas H.

    2015-03-01

    Infantile hemangiomas (IH) are common vascular growths that occur in 5-10% of neonates and have the potential to cause disfiguring and even life-threatening complications. Currently, no objective tool exist to monitor either progression or treatment of IH. To address this unmet clinical need, we have developed a handheld wireless device (HWD) that uses diffuse optical spectroscopy for the assessment of IH. The system employs 4 wavelengths (l=780nm, 805nm, 850nm, and 905nm) and 6 source-detector pairs with distances between 0.6 and 20 mm. Placed on the skin surface, backreflection data is obtained and a multispectral evolution algorithm is used to determine total hemoglobin concentration and tissue oxygen saturation. First results of an ongoing pilot study involving 13 patients (average enrollment age = 25 months) suggest that an increase in hypoxic stress over time can lead to the proliferation of IH. Involuting IH lesions showed an increase in tissue oxygen saturation as well as a decrease in total hemoglobin.

  20. Spectroscopic Characterization of Intermediates in the Iron Catalyzed Activation of Alkanes

    Energy Technology Data Exchange (ETDEWEB)

    Edward M. Eyring

    2007-05-28

    The present report begins with a brief survey of recent hypervalent iron chemistry and mentions two previously reported ferrate papers funded by the DOE/BES grant. The focus is then shifted to the seven publications acknowledging support of the grant that have not been reported since the last Progress Report, DOE/ER/14340-9, was prepared. These papers deal with: (a) the successful use of an ATR element in a stopped-flow infrared spectrometer, (b) the rationalization of a depolarization of a LiClO4 solution in polyethylene oxide high polymer, (c) an analysis of several coupled ultrasonic relaxations observed in solutions of pentoses undergoing isomerization, (d) the combination of ultrasonic absorption and Raman scattering measurements to elucidate zinc thiocyanate solutions in water, (e) the use of NMR to determine stability constants when LiClO4:12-crown-4 is dissolved in acetonitrile and in methanol, (f) the possible existence of triple ions in low permittivity solutions, and (g) the properties of a high surface area ceria aerogel. Collectively, these papers illustrate advantages of bringing several modern experimental techniques to bear on complex chemical systems.

  1. Facile wet chemical route synthesis, characterization and spectroscopic analysis of yttrium-doped lanthanum phosphate nanoparticles

    Science.gov (United States)

    Raina, Bindu; Verma, Seema; Bamzai, K. K.

    2017-09-01

    Pure and yttrium-doped lanthanum phosphate nanoparticles were successfully prepared through a simple one-step co-precipitation method. The phase, morphology and composition of Y x La1 - x PO4 powders with varying dopant concentration ( x = 0.00, 0.01, 0.03, 0.05) were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) supplemented with energy dispersive X-ray (EDX) analysis and transmission electron microscopy (TEM). XRD analysis reveals the nanocrystalline nature with monoclinic monazite crystal system. SEM and TEM micrographs indicate the formation of ultrafine particles depicting spherical morphology with slight agglomeration and cluster formation. Fourier transform infrared spectroscopy (FTIR) signifies the presence of water vibration modes in a particular wave number along with phosphate group and a slight shift in wave numbers when yttrium is induced into lanthanum phosphate. Thermogravimetric analysis (TGA) reveals that the structural phase transition takes place above 800 °C. Raman spectra gives insight into the order-disorder in the system and shows relevant peaks for symmetric and anti-symmetric of PO4 3-, O-P-O bending mode, rare earth—oxygen vibrations. The fluorescence spectra of the grown compositions were investigated. The results show strong emission peaks at 270 nm excitation, whose intensity increases along with the increasing dopant concentration. Ultraviolet (UV) spectroscopy reveals that the absorption bands lie in the ultraviolet range and the bands are particularly sensitive to the incorporation of dopant ion, i.e., with effect of doping bands shift towards the lower wavelength side.

  2. Spectroscopic, scanning laser OBIC, and I-V/QE characterizations of browned EVA solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Pern, F.J. [National Renewable Energy Lab., Golden, CO (United States); Eisgruber, I.L. [Materials Research Group, Inc., Wheat Ridge, CO (United States); Micheels, R.H. [Polestar Technologies, Inc., Needham Hts, MA (United States)

    1996-05-01

    The effects of ethylene-vinyl acetate (EVA) discoloration due to accelerated field or laboratory exposure on the encapsulated silicon (Si) solar cells or EVA/glass laminates were characterized quantitatively by using non-invasive, non-destructive ultraviolet-visible (UV-vis) spectrophotometry, spectrocolorimetry, spectrofluorometry, scanning laser OBIC (optical beam induced current) spectroscopy, and current-voltage (I-V) and quantum efficiency (QE) measurements. The results show that the yellowness index (YI) measured directly over the AR-coated solar cells under the glass superstrate increased from the range of -80 to -90 to the range of -20 to 15 as the EVA changed from clear to brown. The ratio of two fluorescence emission peak areas generally increased from 1.45 to 5.69 as browning increased, but dropped to 4.21 on a darker EVA. For a solar cell with brown EVA in the central region, small-area grating QE measurements and scanning laser OBIC analysis between the brown and clear EVA regions showed that the quantum efficiency loss at 633 nm was 42%-48% of the loss at 488 nm, due to a reduced decrease of transmittance in browned EVA at the longer wavelengths. The portion of the solar cell under the browned EVA showed a decrease of {approximately}36% in efficiency, as compared to the cell efficiency under clear EVA. Transmittance loss at 633 nm was 38% of the loss at 488 nm for a light yellow-brown EVA/glass laminate that showed a small increase of 10 in the yellowness index.

  3. (TAML)FeIV O complex in aqueous solution: synthesis and spectroscopic and computational characterization.

    Science.gov (United States)

    Chanda, Arani; Shan, Xiaopeng; Chakrabarti, Mrinmoy; Ellis, W Chadwick; Popescu, Delia L; Tiago de Oliveira, Filipe; Wang, Dong; Que, Lawrence; Collins, Terrence J; Münck, Eckard; Bominaar, Emile L

    2008-05-05

    Recently, we reported the characterization of the S = (1)/ 2 complex [Fe (V)(O)B*] (-), where B* belongs to a family of tetraamido macrocyclic ligands (TAMLs) whose iron complexes activate peroxides for environmentally useful applications. The corresponding one-electron reduced species, [Fe (IV)(O)B*] (2-) ( 2), has now been prepared in >95% yield in aqueous solution at pH > 12 by oxidation of [Fe (III)(H 2O)B*] (-) ( 1), with tert-butyl hydroperoxide. At room temperature, the monomeric species 2 is in a reversible, pH-dependent equilibrium with dimeric species [B*Fe (IV)-O-Fe (IV)B*] (2-) ( 3), with a p K a near 10. In zero field, the Mössbauer spectrum of 2 exhibits a quadrupole doublet with Delta E Q = 3.95(3) mm/s and delta = -0.19(2) mm/s, parameters consistent with a S = 1 Fe (IV) state. Studies in applied magnetic fields yielded the zero-field splitting parameter D = 24(3) cm (-1) together with the magnetic hyperfine tensor A/ g nbeta n = (-27, -27, +2) T. Fe K-edge EXAFS analysis of 2 shows a scatterer at 1.69 (2) A, a distance consistent with a Fe (IV)O bond. DFT calculations for [Fe (IV)(O)B*] (2-) reproduce the experimental data quite well. Further significant improvement was achieved by introducing hydrogen bonding of the axial oxygen with two solvent-water molecules. It is shown, using DFT, that the (57)Fe hyperfine parameters of complex 2 give evidence for strong electron donation from B* to iron.

  4. Synthesis, crystal structure, spectroscopic characterization and nonlinear optical properties of Co(II)- picolinate complex

    Energy Technology Data Exchange (ETDEWEB)

    Tamer, Ömer, E-mail: omertamer@sakarya.edu.tr; Avcı, Davut; Atalay, Yusuf

    2015-11-15

    A cobalt(II) complex of picolinate was synthesized, and its structure was fully characterized by the applying of X-ray diffraction method as well as FT-IR, FT-Raman and UV–vis spectroscopies. In order to both support the experimental results and convert study to more advanced level, density functional theory calculations were performed by using B3LYP level. Single crystal X-ray structural analysis shows that cobalt(II) ion was located to the center of distorted octahedral geometry. The C=O, C=C and C=N stretching vibrations were found as highly active and strong peaks, inducing the molecular charge transfer within Co(II) complex. The small energy gap between frontier molecular orbital energies was another indicator of molecular charge transfer interactions within Co(II) complex. The nonlinear optical properties of Co(II) complex were investigated at DFT/B3LYP level, and the hypepolarizability parameter was found to be decreased due to the presence of inversion symmetry. The natural bond orbital (NBO) analysis was performed to investigate molecular stability, hyperconjugative interactions, intramolecular charge transfer (ICT) and bond strength for Co(II) complex. Finally, molecular electrostatic potential (MEP) and spin density distributions for Co(II) complex were evaluated. - Highlights: • Co(II) complex of picolinate was prepared. • Its FT-IR, FT-Raman and UV–vis spectra were measured. • DFT calculations were performed to support experimental results. • Small HOMO-LUMO energy gap is an indicator of molecular charge transfer. • Spin density localized on Co(II) as well as O and N atoms.

  5. Raman, infrared and near-infrared spectroscopic characterization of the herderite-hydroxylherderite mineral series.

    Science.gov (United States)

    Frost, Ray L; Scholz, Ricardo; López, Andrés; Xi, Yunfei; Queiroz, Camila de Siqueira; Belotti, Fernanda M; Cândido Filho, Mauro

    2014-01-24

    Natural single-crystal specimens of the herderite-hydroxylherderite series from Brazil, with general formula CaBePO4(F,OH), were investigated by electron microprobe, Raman, infrared and near-infrared spectroscopies. The minerals occur as secondary products in granitic pegmatites. Herderite and hydroxylherderite minerals show extensive solid solution formation. The Raman spectra of hydroxylherderite are characterized by bands at around 985 and 998 cm(-1), assigned to ν1 symmetric stretching mode of the HOPO3(3-) and PO4(3-) units. Raman bands at around 1085, 1128 and 1138 cm(-1) are attributed to both the HOP and PO antisymmetric stretching vibrations. The set of Raman bands observed at 563, 568, 577, 598, 616 and 633 cm(-1) are assigned to the ν4 out of plane bending modes of the PO4 and H2PO4 units. The OH Raman stretching vibrations of hydroxylherderite were observed ranging from 3626 cm(-1) to 3609 cm(-1). The infrared stretching vibrations of hydroxylherderites were observed between 3606 cm(-1) and 3599 cm(-1). By using a Libowitzky type function, hydrogen bond distances based upon the OH stretching bands were calculated. Characteristic NIR bands at around 6961 and 7054 cm(-1) were assigned to the first overtone of the fundamental, whilst NIR bands at 10,194 and 10,329 cm(-1) are assigned to the second overtone of the fundamental OH stretching vibration. Insight into the structure of the herderite-hydroxylherderite series is assessed by vibrational spectroscopy. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Spectroscopic characterization of a (6-4) photolyase from the green alga Ostreococcus tauri.

    Science.gov (United States)

    Usman, Anwar; Brazard, Johanna; Martin, Monique M; Plaza, Pascal; Heijde, Marc; Zabulon, Gérald; Bowler, Chris

    2009-07-17

    The cofactor content of OtCPF1, a (6-4) photolyase isolated from the green marine alga Ostreococcus tauri, was characterized by steady-state absorption and fluorescence spectroscopy. The heterologously expressed, GST-fused, purified protein (MW: 89kDa) is non-covalently bound to flavin adenine dinucleotide (FAD), with a flavin to apoprotein molecular ratio of 64%. No light-harvesting chromophore was found in this protein. In freshly purified OtCPF1, FAD is present in three different redox states: the fully oxidized form (FAD(ox), 82%), the neutral semiquinone (FADH*, 14%) and the fully reduced anion (FADH-, 4%). Keeping the sample in the dark, at 5 degrees C, yields oxidation of FADH* and FADH-, partial release of FAD to the solution and slow degradation of the protein. Upon steady-state blue-light irradiation of OtCPF1 at 450nm, photoreduction processes leading to an accumulation of stable FADH* and FADH- species are observed. We demonstrate that this accumulation is due to the presence of an external electron donor agent in the purification buffer. Composition changes observed under steady-state photoexcitation are interpreted in terms of photoinduced reductions of FAD(ox) and FADH* states and competitive back reactions. Specific irradiation by red light at 620 nm shows both photoreduction of FADH* to FADH- and irreversible oxidation of FADH* to FAD(ox). The photoinduced oxidation reaction is believed to be indirectly caused by the external donor agent present in the buffer. Photoexcitation is also shown to stabilize the binding of FAD to the protein. We suggest this effect to be due to slight changes in the protein conformation, possibly strengthening the hydrogen-bonding network surrounding FAD.

  7. Reliable structural, thermodynamic, and spectroscopic properties of organic molecules adsorbed on silicon surfaces from computational modeling: the case of glycine@Si(100).

    Science.gov (United States)

    Carnimeo, Ivan; Biczysko, Malgorzata; Bloino, Julien; Barone, Vincenzo

    2011-10-06

    Chemisorption of glycine on Si(100) has been studied by an integrated computational strategy based on perturbative anharmonic computations employing geometries and harmonic force fields evaluated by hybrid density functionals coupled to purposely tailored basis sets. It is shown that such a strategy allows the prediction of spectroscopic properties of isolated and chemisorbed molecules with comparable accuracy, paving the route toward a detailed analysis of surface-induced changes of glycine vibrational spectra.

  8. Synthesis, spectroscopic characterization, molecular modeling and eukaryotic DNA degradation of new hydrazone complexes

    Directory of Open Access Journals (Sweden)

    Ahmed A. El-Asmy

    2017-02-01

    Full Text Available 2,5-Hexanedione bis(salicyloylhydrazone [H4L] formed novel complexes with some transition metal ions. H4L and its complexes were characterized by elemental analyses, spectral (IR, 1H NMR, ESR and MS, thermal and magnetic measurements. The complexes have the formulae [VO(H2L]·2H2O, [Ni(H2L]·3H2O, [Zn(H2L], [Ni(H4LCl2]·2H2O and [Cr2(H2L(OAc2(OH2]–·2H2O, [Cu(H4L (H2L(EtOH2]·2H2O, [Co2(H2L(OAc2]·H2O, [Mn2(H2L–(OH2]·H2O [Cu2(H2L(OAc2(H2O6], and [Co2(H2L(H2O4Cl2]·2H2O. H4L released its OH or NH protons during the complex formation. Acetate and hydroxo groups bridged the two chromium in [Cr2(H2L(OAc2(OH2]·2H2O. The magnetic moments and electronic spectra of all complexes provide: tetrahedral for [Co2(H2L(OAc2]·H2O, [Ni(H2L]·3H2O and [Zn(H2L]; square-pyramidal for [VO(H2L]·2H2O and octahedral for the rest. In DMF solution, the bands are shifted to higher energy suggesting a weak interaction with the solvent. The ESR spectra support the mononuclear geometry for [VO(H2L]·2H2O and [Cu(H3L2(EtOH2]·2H2O. The thermal decomposition of the complexes revealed the outer and inner solvents as well as the end product which in most cases is metal oxide.

  9. Identification and characterization of the surface proteins of Clostridium difficile

    Energy Technology Data Exchange (ETDEWEB)

    Dailey, D.C.

    1988-01-01

    Several clostridial proteins were detected on the clostridial cell surface by sensitive radioiodination techniques. Two major proteins and six minor proteins comprised the radioiodinated proteins on the clostridial cell surface. Cellular fractionation of surface radiolabeled C. difficile determined that the radioiodinated proteins were found in the cell wall fraction of C. difficile and surprisingly were also present in the clostridial membrane. Furthermore, an interesting phenomenon of disulfide-crosslinking of the cell surface proteins of C. difficile was observed. Disulfide-linked protein complexes were found in both the membrane and cell wall fractions. In addition, the cell surface proteins of C. difficile were found to be released into the culture medium. In attempts to further characterize the clostridial proteins recombinant DNA techniques were employed. In addition, the role of the clostridial cell surface proteins in the interactions of C. difficile with human PMNs was also investigated.

  10. Surface characterization of InP using photoluminescence

    Science.gov (United States)

    Chang, R. R.; Iyer, R.; Lile, D. L.

    1987-01-01

    Photoluminescence (PL) measurements have been performed on InP samples in situ during various surface treatments including chemical etching, wet anodization, and low-pressure chemical vapor deposition. It was found, in agreement with previously published results, that the magnitude of the PL signal varies markedly with surface treatment due presumably to changes in either surface-state density, and/or surface potential. In an attempt to assess the effectiveness of this noninvasive method as a tool for characterizing and monitoring the progressive development of a semiconductor surface during processing, a number of experiments on InP have been performed. The results indicate that although some uncertainty may exist in assigning a mechanism for the PL change in any given experiment, the general trend appears to be that surface degradation results in a reduced signal. As a result, process steps which enhance the PL intensity are likely to be beneficial in the preparation of a high-quality interface.

  11. Spatial characterization of monolithic multi-element Silicon-Drift-Detectors for X-ray spectroscopic applications

    CERN Document Server

    Kappen, P; Hansen, K; Reckleben, C; Lechner, P; Strüder, L; Materlik, G

    2001-01-01

    Spatially resolved spectroscopic measurements with a 10 and 20 mu m pencil beam have been performed on a monolithic 7-element Silicon-Drift-Detector (SDD). Detailed studies are shown of the modification of the spectroscopic response at pixel edges and pixel centre. The results give quantitative insight into the local SDD performance. A simple model predicts global properties (e.g. peak-to-background ratio) of larger SDD arrays, like the 61-element detector currently under development.

  12. Spectroscopic characterizations of non-amphiphilic 2-(4-biphenylyl)-6-phenyl benzoxazole molecules at the air-water interface and in Langmuir-Blodgett films

    Energy Technology Data Exchange (ETDEWEB)

    Hussain, S.A. [Department of Physics, Tripura University, Suryamaninagar, Agartala: 799130 Tripura (India); Deb, S. [Department of Physics, Tripura University, Suryamaninagar, Agartala: 799130 Tripura (India); Bhattacharjee, D. [Department of Physics, Tripura University, Suryamaninagar, Agartala: 799130 Tripura (India)]. E-mail: tuphysic@sancharnet.in

    2005-09-15

    This communication reports about the successful incorporation of a well-known non-amphiphilic derivative of oxazole chromophore 2-(4-biphenylyl)-6-phenyl benzoxazole abbreviated as PBBO, in Langmuir-Blodgett films when mixed with stearic acid (SA) as well as also an inert polymer matrix polymethylmethacrylate (PMMA). The surface pressure versus area per molecule isotherms of the Langmuir films of PBBO mixed with PMMA or SA at different mole fractions reveal that the area per molecule decreases consistently with increasing mole fractions of PBBO. Area per molecule versus mole fraction curve shows that the experimental data points coincide with the ideality curve predicted by the additivity rule, which leads to the conclusion of either ideal mixing or complete demixing of the binary components. The UV-vis absorption and fluorescence spectroscopic studies of mixed LB films of PBBO reveal the nature of complete demixing of the binary components of the sample molecules (PBBO) and PMMA or SA molecules. This complete demixing leads to the formation of clusters and aggregates of PBBO molecules in Langmuir and Langmuir-Blodgett films. J-type aggregates of PBBO molecules in LB films have been confirmed by UV-vis absorption spectroscopic study. Aggregation of PBBO molecules in LB films giving rise to excimeric emission has been demonstrated by fluorescence spectroscopic study. Excitation spectroscopic study clearly confirmed the presence of excimeric sites.

  13. Magnetic Resonance Spectroscopic Imaging of Tumor Metabolic Markers for Cancer Diagnosis, Metabolic Phenotyping, and Characterization of Tumor Microenvironment

    Directory of Open Access Journals (Sweden)

    Qiuhong He

    2004-01-01

    Full Text Available Cancer cells display heterogeneous genetic characteristics, depending on the tumor dynamic microenvironment. Abnormal tumor vasculature and poor tissue oxygenation generate a fraction of hypoxic tumor cells that have selective advantages in metastasis and invasion and often resist chemo- and radiation therapies. The genetic alterations acquired by tumors modify their biochemical pathways, which results in abnormal tumor metabolism. An elevation in glycolysis known as the “Warburg effect” and changes in lipid synthesis and oxidation occur. Magnetic resonance spectroscopy (MRS has been used to study tumor metabolism in preclinical animal models and in clinical research on human breast, brain, and prostate cancers. This technique can identify specific genetic and metabolic changes that occur in malignant tumors. Therefore, the metabolic markers, detectable by MRS, not only provide information on biochemical changes but also define different metabolic tumor phenotypes. When combined with the contrast-enhanced Magnetic Resonance Imaging (MRI, which has a high sensitivity for cancer diagnosis, in vivo magnetic resonance spectroscopic imaging (MRSI improves the diagnostic specificity of malignant human cancers and is becoming an important clinical tool for cancer management and care. This article reviews the MRSI techniques as molecular imaging methods to detect and quantify metabolic changes in various tumor tissue types, especially in extracranial tumor tissues that contain high concentrations of fat. MRI/MRSI methods have been used to characterize tumor microenvironments in terms of blood volume and vessel permeability. Measurements of tissue oxygenation and glycolytic rates by MRS also are described to illustrate the capability of the MR technology in probing molecular information non-invasively in tumor tissues and its important potential for studying molecular mechanisms of human cancers in physiological conditions.

  14. STUDIES ON THE PHYTOCHEMISTRY, SPECTROSCOPIC CHARACTERIZATION AND SCREENING FOR ANTI-MITOTIC EFFICACY OF SALICORNIA BRACHIATA ROXB

    Directory of Open Access Journals (Sweden)

    G.V.Pavan Kumar

    2014-10-01

    Full Text Available Salicorniabrachiata is a euhalopytic plant belonging to the family Chenopodiaceae. The present study investigates the phytochemistry, characterization and antimitotic activity of ethanolic extract of S.brachiata.Plants popularly known as Sea asparagus are cooked and eaten or pickled. It is also a good fodder for cattle, sheep and goat. Plant material is also used as raw material in paper and board factories. Its seeds yield high quality edible oil which is highly polyunsaturated and similar to safflower oil in fatty acid.S.brachiata was collected from the back waters of Bapatla,Guntur district. The collected plant material was shade dried and pulverized. The plant material Was studied for phytochemistry,spectroscopic analysis i.e.,UV- Visible, FT-IR and anti mitotic activity.S. brachiata has been prescribed in traditional medicines for the treatment of intestinal ailments, nephropathy, and hepatitis in Oriental countries. In addition, S.brachiata has recently reported to be effective on the atherosclerosis, hyperlipidemia, and diabetes. A variety of pharmacological experiments have revealed that solvent-extracted fractions of S.brachiata exhibited anti-oxidative, anti-microbial, anti-proliferative, and anti-inflammatory activities,supporting rationale behind its several traditional uses.The phytochemical analysis indicates the presence of Tannins and Flavonoids in the plant. UV-Vis Spectrum, used for the quantitative analysis of the plant extract showed peaks at 280 and 290 nm. Identification of the functional groups was performed by FT-IR spectroscopy which confirmed the presence of phenolic, alcoholic and aromatic compounds.

  15. Surface analytical characterization of Streptavidin/poly(3-hexylthiophene) bilayers for bio-electronic applications

    Science.gov (United States)

    Sportelli, M. C.; Picca, R. A.; Manoli, K.; Re, M.; Pesce, E.; Tapfer, L.; Di Franco, C.; Cioffi, N.; Torsi, L.

    2017-10-01

    The analytical performance of bioelectronic devices is highly influenced by their fabrication methods. In particular, the final architecture of field-effect transistor biosensors combining spin-cast poly(3-hexylthiophene) (P3HT) film and a biomolecule interlayer deposited on a SiO2/Si substrate can lead to the development of highly performing sensing systems, such as for the case of streptavidin (SA) used for biotin sensing. To gain a better understanding of the quality of the interfacial area, critical is the assessment of the morphological features characteristic of the adopted biolayer deposition protocol, namely: the layer-by-layer (LbL) approach and the spin coating technique. The present study relies on a combined surface spectroscopic and morphological characterization. Specifically, X-ray photoelectron spectroscopy operated in the parallel angle-resolved mode allowed the non-destructive investigation of the in-depth chemical composition of the SA film, alone or in the presence of the P3HT overlayer. Spectroscopic data were supported and corroborated by the results obtained with a Scanning Electron and a Helium Ion microscope investigation performed on the SA layer that provided relevant information on the protein structural arrangement or on its surface morphology. Clear differences emerged between the SA layers prepared by the two approaches, with the layer-by-layer deposition resulting in a smoother and better defined bio-electronic interface. Such findings support the superior analytical performance shown by bioelectronic devices based on LbL-deposited protein layers over spin coated ones.

  16. Characterization of complementary electric field coupled resonant surfaces

    Science.gov (United States)

    Hand, Thomas H.; Gollub, Jonah; Sajuyigbe, Soji; Smith, David R.; Cummer, Steven A.

    2008-11-01

    We present angle-resolved free-space transmission and reflection measurements of a surface composed of complementary electric inductive-capacitive (CELC) resonators. By measuring the reflection and transmission coefficients of a CELC surface with different polarizations and particle orientations, we show that the CELC only responds to in-plane magnetic fields. This confirms the Babinet particle duality between the CELC and its complement, the electric field coupled LC resonator. Characterization of the CELC structure serves to expand the current library of resonant elements metamaterial designers can draw upon to make unique materials and surfaces.

  17. Characterization of novel silane coatings on titanium implant surfaces

    NARCIS (Netherlands)

    Matinlinna, Jukka P; Tsoi, James Kit‐Hon; de Vries, Jacob; Busscher, Hendrik

    2013-01-01

    Objectives This in vitro study describes and characterizes a developed novel method to produce coatings on Ti. Hydrophobic coatings on substrates are needed in prosthetic dentistry to promote durable adhesion between luting resin cements and coated Ti surfaces. In implant dentistry the hydrophobic c

  18. Bulk and surface characterization of novel photoresponsive polymeric systems

    Science.gov (United States)

    Venkataramani, Shivshankar

    This dissertation presents a detailed characterization of two important classes of photoresponsive polymers-polydiacetylenes (PDAs) and azopolymers. Bulk and surface characterization techniques were used to evaluate the structure-property relationships of the PDAs and surface characterization, in particular-atomic force microscopy (AFM) was used to characterize the azopolymers. PDAs from bis-alkylurethanes of 5,7 dodecadiyn 1,12-diol (viz.,) ETCD, IPUDO and PUDO are of particular interest in view of reports of reversible thermochromic and photochromic phase transitions in these materials. Thermochromism in the above PDAs is associated with a first order phase transition involving expansion of the crystallographic unit cell, the preservation of the urethane hydrogen bonding and possibly some relief of mechanical strain upon heating. Insights into thermochromism obtained from studies of nonthermochromic forms of PDA-ETCD are discussed. Some of the bulk characterization experiments reported In the literature are repeated. The motivation to investigate the surface morphology of the PDA single crystals using AFM was derived from Raman spectroscopy studies of various PDAs in which dispersion of the Raman spectrum indicating surface heterogeneity was observed. Micron scale as well as molecularly resolved images were obtained The micron scale images indicated a variable surface of the crystals. The molecularly resolved images showed a well defined 2-D lattice and are interpreted in terms of known crystallographic data. The surface parameters obtained from AFM measurements are similar to those determined from X-ray diffraction. During an attempt of AFM imaging of IPUDO crystals exposed to 254 nm ultraviolet light, it was observed that these crystals undergo a "macroscopic shattering". In the interest of rigorously defining conditions for photochromism, this research has undertaken a combined study of the surface morphology of the above mentioned PDA crystals by AFM and the

  19. Material, Mechanical, and Tribological Characterization of Laser-Treated Surfaces

    Science.gov (United States)

    Yilbas, Bekir Sami; Kumar, Aditya; Bhushan, Bharat; Aleem, B. J. Abdul

    2014-10-01

    Laser treatment under nitrogen assisting gas environment of cobalt-nickel-chromium-tungsten-based superalloy and high-velocity oxygen-fuel thermal spray coating of nickel-chromium-based superalloy on carbon steel was carried out to improve mechanical and tribological properties. Superalloy surface was preprepared to include B4C particles at the surface prior to the laser treatment process. Material and morphological changes in the laser-treated samples were examined using scanning electron microscopy, energy-dispersive spectroscopy, and x-ray diffraction (XRD) analysis. Residual stresses present at the surface region of the laser-treated layer were determined from the XRD data. The microhardness of the laser-treated surface was measured by indentation tests. Fracture toughness of the coating surfaces before and after laser treatment were also measured using overload indentation tests. Macrowear and macrofriction characterization were carried out using pin-on-disk tests.

  20. Accurate spectroscopic characterization of oxirane: A valuable route to its identification in Titan's atmosphere and the assignment of unidentified infrared bands

    Energy Technology Data Exchange (ETDEWEB)

    Puzzarini, Cristina [Dipartimento di Chimica " Giacomo Ciamician," Università di Bologna, Via Selmi 2, I-40126 Bologna (Italy); Biczysko, Malgorzata; Bloino, Julien; Barone, Vincenzo, E-mail: cristina.puzzarini@unibo.it [Scuola Normale Superiore, Piazza dei Cavalieri 7, I-56126 Pisa (Italy)

    2014-04-20

    In an effort to provide an accurate spectroscopic characterization of oxirane, state-of-the-art computational methods and approaches have been employed to determine highly accurate fundamental vibrational frequencies and rotational parameters. Available experimental data were used to assess the reliability of our computations, and an accuracy on average of 10 cm{sup –1} for fundamental transitions as well as overtones and combination bands has been pointed out. Moving to rotational spectroscopy, relative discrepancies of 0.1%, 2%-3%, and 3%-4% were observed for rotational, quartic, and sextic centrifugal-distortion constants, respectively. We are therefore confident that the highly accurate spectroscopic data provided herein can be useful for identification of oxirane in Titan's atmosphere and the assignment of unidentified infrared bands. Since oxirane was already observed in the interstellar medium and some astronomical objects are characterized by very high D/H ratios, we also considered the accurate determination of the spectroscopic parameters for the mono-deuterated species, oxirane-d1. For the latter, an empirical scaling procedure allowed us to improve our computed data and to provide predictions for rotational transitions with a relative accuracy of about 0.02% (i.e., an uncertainty of about 40 MHz for a transition lying at 200 GHz).

  1. Ultrasonic characterization of shot-peened metal surfaces

    Science.gov (United States)

    Lavrentyev, Anton I.; Veronesi, William A.

    2001-08-01

    Shot peening is a well-known method for extending the fatigue life of metal components by introducing near-surface compressive residual stresses. The capability to nondestructively evaluate near-surface residual stress would greatly aid the assurance of proper fatigue life in shot-peened components. This paper describes our work on near-surface residual stress measurement by an ultrasonic surface wave method. In this method, a variation of ultrasonic surface wave speed with shot peening intensity is measured. Since the effective wave penetration depth is inversely related to the excitation frequency, the method has the potential to provide the stress-depth profile. The paper presents results from an ultrasonic characterization study of shot peened Al-7075 and Waspaloy surfaces. Rayleigh wave velocity measurements by a V(z)-curve method were made on smooth and shot peened samples using line-focus ultrasonic transducers. Several factors were found to contribute to the surface wave velocity measurements: surface roughness, near-surface grain reorientation (texture), dislocation density increase, and residual stress. In this paper we estimate quantitatively the effects of each factor and discuss how these effects can be separated and accounted for during residual stress measurement.

  2. 16-Channel surface coil for 13C-hyperpolarized spectroscopic imaging of cardiac metabolism in pig heart

    DEFF Research Database (Denmark)

    Frijia, Francesca; Santarelli, Maria Filomena; Koellisch, Ulrich;

    2016-01-01

    both targets. In this study, a 16-channel receive surface coil was designed for 13C hyperpolarized studies of the pig heart with a clinical 3-T scanner. The coil performance was characterized by phantom experiments and compared with that of a birdcage coil used in transmit/receive mode. Segmental...... limitation due to the low molar concentration of certain metabolites as well as the low flux of conversion. Since 13C-MRS is essentially a semi-quantitative technique, the SNR of the spectra acquired in different myocardial segments should be homogeneous. MRS coil design plays an important role in achieving...... signal distribution in the left ventricle (LV) was assessed by experiments on six healthy mini pigs. The proposed coil showed a significant increase in SNR for the LV wall close to the coil surface with respect to that for the birdcage but also significant segmental inhomogeneity. Hence, the use...

  3. Spectroscopic Characterization of Microplasmas

    Science.gov (United States)

    2009-09-20

    solution of electrolyte was used and the discharge phenomenon in bubbles generated by electrolysis using optical emission spectroscopy was studied. The...in bubbles generated by electrolysis using optical emission spectroscopy. We also observed the plasma emission spectrum in the discharge in bubbled...iti on ra te (n m /s ) Frequency (kHz) Si Substrate SiO2/Si Substrate Glass SiO2/Si Si Copper (a) (b) D ep os iti on ra te (n m /s ) 5 mm 25 mm

  4. Surface Characterization of Plasma-modified Poplar Veneer: Dynamic Wettability

    Directory of Open Access Journals (Sweden)

    Lijuan Tang

    2014-11-01

    Full Text Available The dynamic wettability of plasma-modified poplar veneer was investigated with sessile adhesive droplets using a wetting model. Dynamic contact angle, instantaneous and equilibrium contact angles, and their rates of change (K-value were used to illustrate the dynamic wetting process. The experiment consisted of selecting treatment parameters (type of gas, power that would lead to the increased wettability of wood. Three resin systems, urea-formaldehyde (UF, phenol-formaldehyde (PF, and diphenylmethylene diisocyanate (MDI, were evaluated. Based on the wetting model, the K-value was used to interpret the kinetics of wetting. The higher the K-value, the faster the contact angle reaches equilibrium, and the faster the liquid penetrates and spreads. Therefore, the model was helpful for characterizing the dynamic wettability of wood surfaces modified with different plasma treatments. The K-values of plasma-treated veneer surfaces at different plasma power levels and with different gases (such as O2, N2, Ar, air, and NH3 were 458% to 653% and 332% to 528% higher than those of untreated veneer surfaces, respectively. In addition, the K-values of the three resins on the oxygen plasma-treated veneer surfaces were 38% to 1204% higher than those on the untreated veneer surfaces. Therefore, this method was helpful for characterizing the dynamic wettability of veneer surfaces modified with plasma treatment.

  5. Fabrication and characterization of hierarchical nanostructured smart adhesion surfaces.

    Science.gov (United States)

    Lee, Hyungoo; Bhushan, Bharat

    2012-04-15

    The mechanics of fibrillar adhesive surfaces of biological systems such as a Lotus leaf and a gecko are widely studied due to their unique surface properties. The Lotus leaf is a model for superhydrophobic surfaces, self-cleaning properties, and low adhesion. Gecko feet have high adhesion due to the high micro/nanofibrillar hierarchical structures. A nanostructured surface may exhibit low adhesion or high adhesion depending upon fibrillar density, and it presents the possibility of realizing eco-friendly surface structures with desirable adhesion. The current research, for the first time uses a patterning technique to fabricate smart adhesion surfaces: single- and two-level hierarchical synthetic adhesive structure surfaces with various fibrillar densities and diameters that allows the observation of either the Lotus or gecko adhesion effects. Contact angles of the fabricated structured samples were measured to characterize their wettability, and contamination experiments were performed to study for self-cleaning ability. A conventional and a glass ball attached to an atomic force microscope (AFM) tip were used to obtain the adhesive forces via force-distance curves to study scale effect. A further increase of the adhesive forces on the samples was achieved by applying an adhesive to the surfaces.

  6. Surface characterization of self-assembled N-Cu nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Cristina, Lucila J.; Moreno-Lopez, Juan C. [Laboratorio de Superficies e Interfaces, Instituto de Desarrollo Tecnologico para la Industria Quimica (CONICET-UNL), Gueemes 3450, (S3000GLN) Santa Fe (Argentina); Sferco, Silvano J. [Laboratorio de Superficies e Interfaces, Instituto de Desarrollo Tecnologico para la Industria Quimica (CONICET-UNL), Gueemes 3450, (S3000GLN) Santa Fe (Argentina); Departamento de Fisica, Facultad de Bioquimica y Ciencias Biologicas, Universidad Nacional del Litoral, Ciudad Universitaria, C.C. 242, (S3000ZAA) Santa Fe (Argentina); Passeggi, Mario C.G.; Vidal, Ricardo A. [Laboratorio de Superficies e Interfaces, Instituto de Desarrollo Tecnologico para la Industria Quimica (CONICET-UNL), Gueemes 3450, (S3000GLN) Santa Fe (Argentina); Ferron, Julio, E-mail: jferron@intec.unl.edu.ar [Laboratorio de Superficies e Interfaces, Instituto de Desarrollo Tecnologico para la Industria Quimica (CONICET-UNL), Gueemes 3450, (S3000GLN) Santa Fe (Argentina); Departamento de Materiales, Facultad de Ingenieria Quimica, Universidad Nacional del Litoral, Santiago del Estero 2829,(S3000AOM) Santa Fe (Argentina)

    2012-01-01

    We report on the process of low energy N{sub 2}{sup +} implantation and annealing of a Cu(0 0 1) surface. Through AES we study the N diffusion process as a function of the substrate temperature. With STM and LEIS we characterize the surface morphology and the electronic structure is analyzed with ARUPS. Under annealing (500 < T < 700 K) N migrates to the surface and reacts forming a Cu{sub x}N compound that decomposes at temperatures above 700 K. LEIS measurements show that N locates on the four-fold hollow sites of the Cu(0 0 1) surface in a c(2 Multiplication-Sign 2) arrangement. Finally, a gap along the [0 0 1] azimuthal direction is determined by ARUPS. DFT calculations provide support to our conclusions.

  7. Evolution of the transfer function characterization of surface scatter phenomena

    Science.gov (United States)

    Harvey, James E.; Pfisterer, Richard N.

    2016-09-01

    Based upon the empirical observation that BRDF measurements of smooth optical surfaces exhibited shift-invariant behavior when plotted versus    o , the original Harvey-Shack (OHS) surface scatter theory was developed as a scalar linear systems formulation in which scattered light behavior was characterized by a surface transfer function (STF) reminiscent of the optical transfer function (OTF) of modern image formation theory (1976). This shift-invariant behavior combined with the inverse power law behavior when plotting log BRDF versus log   o was quickly incorporated into several optical analysis software packages. Although there was no explicit smooth-surface approximation in the OHS theory, there was a limitation on both the incident and scattering angles. In 1988 the modified Harvey-Shack (MHS) theory removed the limitation on the angle of incidence; however, a moderate-angle scattering limitation remained. Clearly for large incident angles the BRDF was no longer shift-invariant as a different STF was now required for each incident angle. In 2011 the generalized Harvey-Shack (GHS) surface scatter theory, characterized by a two-parameter family of STFs, evolved into a practical modeling tool to calculate BRDFs from optical surface metrology data for situations that violate the smooth surface approximation inherent in the Rayleigh-Rice theory and/or the moderate-angle limitation of the Beckmann-Kirchhoff theory. And finally, the STF can be multiplied by the classical OTF to provide a complete linear systems formulation of image quality as degraded by diffraction, geometrical aberrations and surface scatter effects from residual optical fabrication errors.

  8. Surface characterization of commercial oral implants on the nanometer level.

    Science.gov (United States)

    Svanborg, Lory Melin; Andersson, Martin; Wennerberg, Ann

    2010-02-01

    Lately, there has been a growing interest in how the presence of nanometer structures on a bone integrated implant surface influences the healing process. Recent in vitro studies have revealed an increased osteoblast response to different nanophase surfaces. Some commercial implant brands claim their implants have nanometer structures. However, at present, there are no studies where the nano topography of today's commercially available oral implants has been investigated. The aim of this study was to characterize commercial oral implants on the nanometer level and to investigate whether or not the nanometer surface roughness was correlated to the more well-known micrometer roughness on the implants. Twelve different commercial screw-shaped oral implants with various surface modifications were examined using scanning electron microscopy and a white light interferometer. The interferometer is suitable for detection of nanoscale roughness in the vertical dimension; however, limitation exists on the horizontal due to the wavelength of the light. A 1 x 1 microm Gaussian filter was found to be useful for identifying nm roughness with respect to height deviation. The results demonstrated that an implant that was smooth on the micrometer level was not necessarily smooth on the nanometer level. Different structures in the nanometer scale was found on some of the implants, indicating that to fully understand the relationship between the properties of an implant surface and its osseointegration behavior, a characterization at the nanometer scale might be relevant.

  9. Comparison of optical methods for surface roughness characterization

    DEFF Research Database (Denmark)

    Feidenhans'l, Nikolaj Agentoft; Hansen, Poul Erik; Pilny, Lukas;

    2015-01-01

    We report a study of the correlation between three optical methods for characterizing surface roughness: a laboratory scatterometer measuring the bi-directional reflection distribution function (BRDF instrument), a simple commercial scatterometer (rBRDF instrument), and a confocal optical profiler....... For each instrument, the effective range of spatial surface wavelengths is determined, and the common bandwidth used when comparing the evaluated roughness parameters. The compared roughness parameters are: the root-mean-square (RMS) profile deviation (Rq), the RMS profile slope (Rdq), and the variance...

  10. Surface characterization of silver and palladium modified glassy carbon

    Indian Academy of Sciences (India)

    Aleksandra A Perić-Grujić; Olivera M Nešković; Miomir V Veljković; Zoran V Laušević; Mila D Laušević

    2007-12-01

    In this work, the influence of silver and palladium on the surface of undoped, boron doped and phosphorus doped glassy carbon has been studied. The silver and palladium concentrations in solution, after metal deposition, were measured by atomic absorption spectrophotometer. The morphology of metal coatings was characterized by scanning electron microscopy. In order to investigate the nature and thermal stability of surface oxygen groups, temperature-programmed desorption method combined with mass spectrometric analyses, was performed. The results obtained have shown that silver and palladium spontaneously deposit from their salt solutions at the surface of glassy carbon samples. Silver deposits have dendrite structure, whilst palladium forms separate clusters. The highest amount of both silver and palladium deposits at the surface of sample containing the highest quantity of surface oxide complexes. It has been concluded that carboxyl groups and structure defects are responsible for metal reduction. Calculated desorption energies have shown that the surface modification by metal deposition leads to the formation of more stable surface of undoped and doped glassy carbon samples.

  11. Isolation and characterization of bacteria resistant to metallic copper surfaces.

    Science.gov (United States)

    Santo, Christophe Espírito; Morais, Paula Vasconcelos; Grass, Gregor

    2010-03-01

    Metallic copper alloys have recently attracted attention as a new antimicrobial weapon for areas where surface hygiene is paramount. Currently it is not understood on a molecular level how metallic copper kills microbes, but previous studies have demonstrated that a wide variety of bacteria, including Escherichia coli, Staphylococcus aureus, and Clostridium difficile, are inactivated within minutes or a few hours of exposure. In this study, we show that bacteria isolated from copper alloy coins comprise strains that are especially resistant against the toxic properties exerted by dry metallic copper surfaces. The most resistant of 294 isolates were Gram-positive staphylococci and micrococci, Kocuria palustris, and Brachybacterium conglomeratum but also included the proteobacterial species Sphingomonas panni and Pseudomonas oleovorans. Cells of some of these bacterial strains survived on copper surfaces for 48 h or more. Remarkably, when these dry-surface-resistant strains were exposed to moist copper surfaces, resistance levels were close to those of control strains and MICs for copper ions were at or below control strain levels. This suggests that mechanisms conferring resistance against dry metallic copper surfaces in these newly isolated bacterial strains are different from well-characterized copper ion detoxification systems. Furthermore, staphylococci on coins did not exhibit increased levels of resistance to antibiotics, arguing against coselection with copper surface resistance traits.

  12. Electrochemical characterization of organosilane-functionalized nanostructured ITO surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Pruna, R., E-mail: rpruna@el.ub.edu; Palacio, F.; López, M. [SIC, Departament d' Enginyeries: Electrònica, Universitat de Barcelona, C/ Martí i Franquès 1, E-08028 Barcelona (Spain); Pérez, J. [Nanobioengineering Group, Institute for Bioengineering of Catalonia (IBEC), Baldiri Reixac 15-21, E-08028 Barcelona (Spain); Mir, M. [Nanobioengineering Group, Institute for Bioengineering of Catalonia (IBEC), Baldiri Reixac 15-21, E-08028 Barcelona (Spain); Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Monforte de Lemos 3-5 Pabellón 11, E-28029 Madrid (Spain); Blázquez, O.; Hernández, S.; Garrido, B. [MIND-IN" 2UB, Departament d' Enginyeries: Electrònica, Universitat de Barcelona, C/ Martí i Franquès 1, E-08028 Barcelona (Spain)

    2016-08-08

    The electroactivity of nanostructured indium tin oxide (ITO) has been investigated for its further use in applications such as sensing biological compounds by the analysis of redox active molecules. ITO films were fabricated by using electron beam evaporation at different substrate temperatures and subsequently annealed for promoting their crystallization. The morphology of the deposited material was monitored by scanning electron microscopy, confirming the deposition of either thin films or nanowires, depending on the substrate temperature. Electrochemical surface characterization revealed a 45 % increase in the electroactive surface area of nanostructured ITO with respect to thin films, one third lower than the geometrical surface area variation determined by atomic force microscopy. ITO surfaces were functionalized with a model organic molecule known as 6-(ferrocenyl)hexanethiol. The chemical attachment was done by means of a glycidoxy compound containing a reactive epoxy group, the so-called 3-glycidoxypropyltrimethoxy-silane. ITO functionalization was useful for determining the benefits of nanostructuration on the surface coverage of active molecules. Compared to ITO thin films, an increase in the total peak height of 140 % was observed for as-deposited nanostructured electrodes, whereas the same measurement for annealed electrodes resulted in an increase of more than 400 %. These preliminary results demonstrate the ability of nanostructured ITO to increase the surface-to-volume ratio, conductivity and surface area functionalization, features that highly benefit the performance of biosensors.

  13. Characterization and reactivity of sodium aluminoborosilicate glass fiber surfaces

    Science.gov (United States)

    Ortiz Rivera, Lymaris; Bakaev, Victor A.; Banerjee, Joy; Mueller, Karl T.; Pantano, Carlo G.

    2016-05-01

    Multicomponent complex oxides, such as sodium aluminoborosilicate glass fibers, are important materials used for thermal insulation in buildings and homes. Although the surface properties of single oxides, such as silica, have been extensively studied, less is known about the distribution of reactive sites at the surface of multicomponent oxides. Here, we investigated the reactivity of sodium aluminoborosilicate glass fiber surfaces for better understanding of their interface chemistry and bonding with acrylic polymers. Acetic acid (with and without a 13C enrichment) was used as a probe representative of the carboxylic functional groups in many acrylic polymers and adhesives. Inverse gas chromatography coupled to a mass spectrometer (IGC-MS), and solid state nuclear magnetic resonance (NMR), were used to characterize the fiber surface reactions and surface chemical structure. In this way, we discovered that both sodium ions in the glass surface, as well as sodium carbonate salts that formed on the surface due to the intrinsic reactivity of this glass in humid air, are primary sites of interaction with the carboxylic acid. Surface analysis by X-ray photoelectron spectroscopy (XPS) confirmed the presence of sodium carbonates on these surfaces. Computer simulations of the interactions between the reactive sites on the glass fiber surface with acetic acid were performed to evaluate energetically favorable reactions. The adsorption reactions with sodium in the glass structure provide adhesive bonding sites, whereas the reaction with the sodium carbonate consumes the acid to form sodium-carboxylate, H2O and CO2 without any contribution to chemical bonding at the interface.

  14. Semiconductor Surface Characterization Using Transverse Acoustoelectric Voltage versus Voltage Measurements.

    Science.gov (United States)

    1982-10-01

    Das, R. T. Webster and B. Davari, "SAW Characterization of Photo- Voltaic Solar Cell", Electrochemical Society Extended Abstracts, Vol. 79-1, Spring...Measurement of Carrier Generation Rate in Semiconductors", presented at the 153rd Meeting of the Electrochemical Society , Seattle, Washington, May 21-26...Ion-implanted Silicon by Surface Acoustic Waves", presented at the Electrochemical Society Meeting, May 6-11, 1979, Boston, Massachusetts. 6. P. Das, M

  15. Surface topography characterization of automotive cylinder liner surfaces using fractal methods

    Science.gov (United States)

    Lawrence K, Deepak; Ramamoorthy, B.

    2013-09-01

    This paper explores the use of fractal approaches for the possible characterization of automotive cylinder bore surface topography by employing methods such as differential box counting method, power spectral method and structure function method. Three stage plateau honing experiments were conducted to manufacture sixteen cylinder liner surfaces with different surface topographies, for the study. The three fractal methods are applied on the image data obtained using a computer vision system and 3-D profile data obtained using vertical scanning white light interferometer from the cylinder liner surfaces. The computed fractal parameters (fractal dimension and topothesy) are compared and correlated with the measured 3-D Abbott-Firestone curve parameters (Sk, Spk, Svk, Sr1 and Sr2) that are currently used for the surface topography characterization cylinder liner surfaces. The analyses of the results indicated that the fractal dimension (D) computed using the vision data as well as 3-D profile data by employing three different fractal methods consistantly showed a negative correlation with the functional surface topographical parameters that represents roughness at peak (Spk),core (Sk) and valley (Svk) regions and positive correlation with the upper bearing area (Sr1) and lower bearing area (Sr2) of the automotive of cylinder bore surface.

  16. Molecular engineering and characterization of self-assembled biorecognition surfaces

    Science.gov (United States)

    Pan, Sheng

    . The surface reaction process was systematically characterized by ESCA. In vitro cell adhesion studies demonstrated that the designed surfaces had the capability to stimulate cell attachment and spreading, even in the absence of serum proteins. The biospecific recognition between the surface and the cell receptors was attributed to the appropriate chemical environment and statistical pattern matching between the randomly distributed R+G+D groups on the surface and cell receptors.

  17. Synthesis, spectroscopic characterization and catalytic oxidation properties of ONO/ONS donor Schiff base ruthenium(III) complexes containing PPh3/AsPh3

    Indian Academy of Sciences (India)

    Priyarega; M Muthu Tamizh; R Karvembu; R Prabhakaran; K Natarajan

    2011-05-01

    Six different ruthenium(III) complexes of Schiff bases derived from 2-hydroxy-1-naphthaldehyde and -aminophenol/-aminothiophenol have been synthesized. The compounds with the general formula [RuX(EPh3)2(L)] (X = Cl or Br; E = P or As; L = bifunctional tridentate ONO/ONS donor Schiff base ligand) were characterized by infrared, electronic, electron paramagnetic resonance spectroscopy and elemental analyses. Spectroscopic investigation reveals coordination of Schiff base ligand through ONO/ONS donor atoms and octahedral geometry around ruthenium metal. Redox property of complexes has been examined by using cyclic voltammetry. The catalytic oxidation property of ruthenium(III) complexes were also investigated.

  18. Synthesis, Characterization and Spectroscopic Studies of A Novel 2-[(E-[(2,4-dichlorophenylimino]methyl]phenol Schiff Base and Its Metal Complexes

    Directory of Open Access Journals (Sweden)

    Eman Turky Shamkhy

    2012-01-01

    Full Text Available A novel Schiff base 2-{(E-[(2,4-dichlorophenylimino]methyl}phenol (LB was synthesized from the condensation reaction of 2,4-dichloroaniline with salicyladehyde in [1:1] ratio in the presence of glacial acetic acid as catalyst. Complexation reaction of this Schiff base with copper (II, cobalt (II as nitrate salts and with Rhodium (III as chloride salt to produce three coordinate metal complexes, with a Schiff base: Metal ion ratio of 2:1. These compounds have been characterized by a variety of physico-chemical and spectroscopic techniques. The ligand and its metal complexes were expected to show an interesting bioactivity and cytotoxicity.

  19. Multiple focused EMAT designs for improved surface breaking defect characterization

    Science.gov (United States)

    Thring, C. B.; Fan, Y.; Edwards, R. S.

    2017-02-01

    Ultrasonic Rayleigh waves can be employed for the detection of surface breaking defects such as rolling contact fatigue and stress corrosion cracking. Electromagnetic Acoustic Transducers (EMATs) are well suited to this technique as they can directly generate Rayleigh waves within the sample without the requirement for wedges, and they are robust and inexpensive compared to laser ultrasonics. Three different EMAT coil types have been developed, and these are compared to assess their ability to detect and characterize small (down to 0.5 mm depth, 1 mm diameter) surface breaking defects in aluminium. These designs are: a pair of linear meander coils used in a pseudo-pulse-echo mode, a pair of focused meander coils also used in pseudo-pulse-echo mode, and a pair of focused racetrack coils used in pitch-catch mode. The linear meander coils are able to detect most of the defects tested, but have a much lower signal to noise ratio and give limited sizing information. The focused meander coils and the focused racetrack coils can detect all defects tested, but have the advantage that they can also characterize the defect sizes on the sample surface, and have a stronger sensitivity at their focal point. Measurements using all three EMAT designs are presented and compared for high resolution imaging of surface-breaking defects.

  20. Characterization of treated porcelain surfaces via dynamic contact angle analysis.

    Science.gov (United States)

    Phoenix, R D; Shen, C

    1995-01-01

    Successful porcelain repair requires conditioning of porcelain surfaces. Conditioning is intended to facilitate wetting by repair materials and improve interfacial bonding. The objective of this investigation was to determine the effects of selected surface treatments upon the wettability of a representative feldspathic porcelain. Dynamic contact angle analysis and scanning electron microscopy were used to characterize the effects of such treatments. Standardized porcelain specimens were subjected to the following five treatment regimens: (1) control (no treatment); (2) airborne particle abrasion using 50 microns aluminum oxide; (3) etching with ammonium bifluoride gel; (4) etching with acidulated phosphate fluoride gel; and (5) etching with hydrofluoric acid gel. Following treatment, specimens were cleansed and dried. Advancing contact angles were quantified using dynamic contact angle analysis. Mean values and 95% confidence intervals were (in degrees): control, 63.8 +/- 2.7; ammonium bifluoride, 39.4 +/- 2.0; airborne particle abrading, 29.1 +/- 2.9; acidulated phosphate fluoride, 24.9 +/- 1.7; and hydrofluoric acid, 16.5 +/- 1.2. Significant differences were found between all treatment groups (P = .05). Subsequent scanning electron microscopy examination of treated surfaces indicated lesser contact angles were associated with surfaces displaying deeper and wider grooves. Apparently, the resultant increase in surface area produces increased wettability. It is inferred that an increase in surface area may correspond to enhanced resin-porcelain bonding.

  1. Surface characterization and surface electronic structure of organic quasi-one-dimensional charge transfer salts

    DEFF Research Database (Denmark)

    Sing, M.; Schwingenschlögl, U.; Claessen, R.

    2003-01-01

    We have thoroughly characterized the surfaces of the organic charge-transfer salts TTF-TCNQ and (TMTSF)(2)PF6 which are generally acknowledged as prototypical examples of one-dimensional conductors. In particular x-ray-induced photoemission spectroscopy turns out to be a valuable nondestructive d...

  2. A Hirshfeld surface analysis, crystal structure and spectroscopic properties of new Zn(II) complex with N-aminoethylpiperazine ligand

    Science.gov (United States)

    El Glaoui, Maroua; El Glaoui, Maher; Jelsch, Christian; Aubert, Emmanuel; Lefebvre, Frédéric; Ben Nasr, Chérif

    2017-04-01

    A new organic-inorganic hybrid material, 1-amonioethylpiperazine-1, 4-diium tetrachloridozincate(II) chloride, (C6H18N3)[ZnCl4]Cl, has been synthesized and characterized by various physicochemical techniques including UV-visible absorption, Infra-Red (IR), Raman and NMR spectroscopies. The compound crystallizes in the monoclinic system and P21 space group with Z = 2 and the following unit cell dimensions: a = 7.1728 (6), b = 12.4160 (11), c = 8.0278 (7) Å, β = 97.513 (1)°, V = 708.80 (11) Å3. In this structure, the Zn2+ ion, surrounded by four chlorides, adopts a distorted tetrahedral coordination geometry. The structure of this compound consists of monomeric 1-amonioethylpiperazine-1, 4-diium trications and monomeric [ZnCl4]2- and Cl- anions. These entities are interconnected by means of hydrogen bonding contacts [Nsbnd H⋯Cl, Csbnd H⋯Cl], forming a three-dimensional network. Intermolecular interactions were investigated by Hirshfeld surfaces. More than three quarters of the interaction surface in the crystal packing is constituted by attractive and favored H⋯Cl hydrogen bonds. The 13C and 15N CP-MAS NMR spectra are discussed and the vibrational absorption bands were identified by infrared and Raman spectroscopy.

  3. The CoRoT-GES Collaboration: Improving red giants spectroscopic surface gravitity and abundances with asteroseismology

    Science.gov (United States)

    Valentini, M.; Chiappini, C.; Miglio, A.; Montalbán, J.; Rodrigues, T.; Mosser, B.; Anders, F.; the CoRoT RG Group; GES Consortium, the

    2016-09-01

    Nowadays large spectroscopic surveys, like the Gaia-ESO Survey (GES), provide unique stellar databases for better investigating the formation and evolution of our Galaxy. Great attention must be paid to the accuracy of the basic stellar properties derived: large uncertainties in stellar parameters lead to large uncertainties in abundances, distances and ages. Asteroseismology has a key role in this context: when seismic information is combined with information derived from spectroscopic analysis, highly precise constraints on distances, masses, extinction and ages of red giants can be obtained. In the light of this promising joint action, we started the CoRoT-GES collaboration. We present a set of 1111 CoRoT stars, observed by GES from December 2011 to July 2014, these stars belong to the CoRoT field LRc01, pointing at the inner Galactic disk. Among these stars, 534 have reliable global seismic parameters. By combining seismic informations and spectroscopy, we derived precise stellar parameters, ages, kinematic and orbital parameters and detailed element abundances for this sample of stars. We also show that, thanks to asteroseismology, we are able to obtain a higher precision than what can be achieved by the standard spectroscopic means. This sample of CoRoT red giants, spanning Galactocentric distances from 5 to 8 kpc and a wide age interval (1-13 Gyr), provides us a representative sample for the inner disk population.

  4. A simple surface treatment and characterization of AA 6061 aluminum alloy surface for adhesive bonding applications

    Energy Technology Data Exchange (ETDEWEB)

    Saleema, N., E-mail: saleema.noormohammed@imi.cnrc-nrc.gc.ca [National Research Council of Canada (ATC-NRC), 501 Boulevard University East, Saguenay, Quebec G7H 8C3 (Canada); Sarkar, D.K. [Centre Universitaire de Recherche sur l' Aluminium (CURAL), University of Quebec at Chicoutimi (UQAC), 555 Boulevard University East, Saguenay, Quebec G7H 2B1 (Canada); Paynter, R.W. [Institut National de la Recherche Scientifique Energie Materiaux Telecommunications (INRS-EMT), 1650 Boulevard Lionel-Boulet, Varennes, Quebec J3X 1S2 (Canada); Gallant, D.; Eskandarian, M. [National Research Council of Canada (ATC-NRC), 501 Boulevard University East, Saguenay, Quebec G7H 8C3 (Canada)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer A very simple surface treatment method to achieve excellent and durable aluminum adhesive bonding. Black-Right-Pointing-Pointer Our method involves simple immersion of aluminum in very dilute NaOH solution at room temperature with no involvement of strong acids or multiple procedures. Black-Right-Pointing-Pointer Surface analysis via various surface characterization techniques showed morphological and chemical modifications favorable for obtaining highly durable bond strengths on the treated surface. Black-Right-Pointing-Pointer Safe, economical, reproducible and simple method, easily applicable in industries. - Abstract: Structural adhesive bonding of aluminum is widely used in aircraft and automotive industries. It has been widely noted that surface preparation of aluminum surfaces prior to adhesive bonding plays a significant role in improving the strength of the adhesive bond. Surface cleanliness, surface roughness, surface wettability and surface chemistry are controlled primarily by proper surface treatment methods. In this study, we have employed a very simple technique influencing all these criteria by simply immersing aluminum substrates in a very dilute solution of sodium hydroxide (NaOH) and we have studied the effect of varying the treatment period on the adhesive bonding characteristics. A bi-component epoxy adhesive was used to join the treated surfaces and the bond strengths were evaluated via single lap shear (SLS) tests in pristine as well as degraded conditions. Surface morphology, chemistry, crystalline nature and wettability of the NaOH treated surfaces were characterized using various surface analytical tools such as scanning electron microscopy and energy dispersive X-ray analysis (SEM/EDX), optical profilometry, infrared reflection absorption spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction and contact angle goniometry. Excellent adhesion characteristics with complete cohesive failure

  5. Electrochemical synthesis and spectroscopic characterization of poly(N-phenylpyrrole coatings in an organic medium on iron and platinum electrodes

    Directory of Open Access Journals (Sweden)

    A.K.D. Diaw

    2008-12-01

    Full Text Available The electrochemical synthesis of poly(N-phenylpyrrole film was achieved on pretreated iron and platinum electrodes in acetonitrile solutions containing 0.1 M N-phenylpyrrole as the monomer and 0.1 M tetrabutylammonium trifluoromethane sulfonate (Bu4NCF3SO3 as the supporting-salt. The results showed that a surface treatment by 10 % aqueous nitric acid inhibits iron dissolution without preventing the N-phenylpyrrole oxidation. Very strongly adherent films were obtained at constant-potential, constant-current and cyclic voltammetry. XPS measurements, infrared (FT-IR and electronic absorption (UV-vis spectroscopies were used to characterize the iron and platinum-coated electrodes. Finally the anticorrosion properties of the PΦP film were evidenced.

  6. Spectroscopic characterization of cell membranes and their constituents of the plant-associated soil bacterium Azospirillum brasilense

    Science.gov (United States)

    Kamnev, A. A.; Antonyuk, L. P.; Matora, L. Yu.; Serebrennikova, O. B.; Sumaroka, M. V.; Colina, M.; Renou-Gonnord, M.-F.; Ignatov, V. V.

    1999-05-01

    Structural and compositional features of bacterial membranes and some of their isolated constituents (cell surface lipopolysaccharide, phospholipids) of the plant-growth-promoting diazotrophic rhizobacterium Azospirillum brasilense (wild-type strain Sp245) were characterized using Fourier transform infrared (FTIR) spectroscopy and some other techniques. FTIR spectra of the cell membranes were shown to comprise the main vibration modes of the relevant lipopolysaccharide and protein components which are believed to be involved in associative plant-bacterium interactions, as well as of phospholipid constituents. The role and functions of metal cations in the structural organization and physicochemical properties of bacterial cell membranes are also discussed considering their accumulation in the membranes from the culture medium.

  7. Mineralogical Characterization Studies on Unburnt Ceramic Product Made from Rock Residue Additives by Ft-Ir Spectroscopic Technique

    Science.gov (United States)

    Vijayaragavan, R.; Mullainathan, S.; Balachandramohan, M.; Krishnamoorthy, N.; Nithiyanantham, S.; Murugesan, S.; Vanathi, V.

    2013-10-01

    The usability of waste rock (rock residue) powder as an additive material in ceramic samples was investigated. Qualitative analysis was carried out to determine the major and minor constituent minerals present in ceramic bodies made from rock residue powder by using FT-IR spectroscopic technique. Further, the representative ceramic bodies are analyzed by FT-IR technique to yield more information about the functional groups and also to estimate the order or disorder of kaolinite structure.

  8. Chemical characterization of the surface sites of coal

    Energy Technology Data Exchange (ETDEWEB)

    Fowkes, F.M.; Kardos, K.; Riddle, F.L. Jr.; Cole, D.A.

    1990-08-01

    We propose to do experimental studies in four related areas concerning the acid-base properties of coal surfaces: (1) develop high precision flow microcalorimetric methods for determining the concentrations and strengths of the acidic and basic surface sites of coal powders: (2) develop photo-acoustic FTIR and solid-state NMR spectral shift techniques for determination of the concentrations and strengths of acidic and basic surface sites of coal powders; (3) determine the concentrations and strengths of the acidic and basic surface sites of some of the well-characterized coal samples from Argonne National Labs., comparing the coal samples before and after demineralization treatments with HCl and HF; (4) study the effects of surface acidity and basicity on the coal/water interface, with emphasis on the role of interfacial acid-base interactions in the adsorption of ions, surfactants and coal/water slurry stabilizers. From measured heats of interaction, a reasonable estimate can be made of the most prevalent functional groups in coal. This quarter, heats of adsorption of phenols and pyridines were investigated. 2 tabs. (CBS)

  9. Preparation and Characterization of Plasma Cu Surface Modified Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiangyu; TANG Bin; FAN Ailan; MA Yong; TIAN Linhai

    2012-01-01

    Cu modified layer was prepared on the surface of AISI304 stainless steel by plasma surface alloying technique.The effects of processing parameters on the thickness,surface topography,microstructure and chemical composition of Cu modified layer were characterized using glow discharge optical emission spectroscopy (GDOES),scanning electron microscopy (SEM) and X-ray diffraction (XRD).The experimental results show that the surface modified layer is a duplex layer (deposited + diffused layer) with thickness of about 26 μm under the optimum process parameters.The modified layer is mainly composed of a mixture of Cu and expanded austenite phase.The ball-on-disk results show that the modified layer possesses low friction coefficients (0.25) and excellent wear resistance (wear volume 0.005× 109 μm3).The Cu modified layer is very effective in killing the bacteria S.aureus.Meanwhile,no viable S.aureus is found after 3 h (100% killed) by contact with the Cu alloyed surface.

  10. Surface-enhanced Raman scattering (SERS) characterization of trace organoarsenic antimicrobials using silver/polydimethylsiloxane nanocomposites.

    Science.gov (United States)

    Olavarría-Fullerton, Jenifier; Wells, Sabrina; Ortiz-Rivera, William; Sepaniak, Michael J; De Jesús, Marco A

    2011-04-01

    Organoarsenic drugs such as roxarsone and 4-arsanilic acid are poultry feed additives widely used in US broilers to prevent coccidosis and to enhance growth and pigmentation. Despite their veterinary benefits there has been growing concern about their use because over 90% of these drugs are released intact into litter, which is often sold as a fertilizing supplement. The biochemical degradation of these antimicrobials in the litter matrix can release significant amounts of soluble As(III) and As(V) to the environment, representing a potential environmental risk. Silver/polydimethylsiloxane (Ag/PDMS) nanocomposites are a class of surfaceenhanced Raman scattering (SERS) substrates that have proven effective for the sensitive, reproducible, and field-adaptable detection of aromatic acids in water. The work presented herein uses for the first time Ag/PDMS nanocomposites as substrates for the detection and characterization of trace amounts of roxarsone, 4-arsanilic acid, and acetarsone in water. The results gathered in this study show that organoarsenic species are distributed into the PDMS surface where the arsonic acid binds onto the embedded silver nanoparticles, enhancing its characteristic 792 cm(-1) stretching band. The chemisorption of the drugs to the metal facilitates its detection and characterization in the parts per million to parts per billion range. An extensive analysis of the distinct spectroscopic features of each drug is presented with emphasis on the interactions of the arsonic acid, amino, and nitro groups with the metal surface. The benefits of SERS based methods for the study of arsenic drugs are also discussed.

  11. Surface microstructure of bitumen characterized by atomic force microscopy.

    Science.gov (United States)

    Yu, Xiaokong; Burnham, Nancy A; Tao, Mingjiang

    2015-04-01

    Bitumen, also called asphalt binder, plays important roles in many industrial applications. It is used as the primary binding agent in asphalt concrete, as a key component in damping systems such as rubber, and as an indispensable additive in paint and ink. Consisting of a large number of hydrocarbons of different sizes and polarities, together with heteroatoms and traces of metals, bitumen displays rich surface microstructures that affect its rheological properties. This paper reviews the current understanding of bitumen's surface microstructures characterized by Atomic Force Microscopy (AFM). Microstructures of bitumen develop to different forms depending on crude oil source, thermal history, and sample preparation method. While some bitumens display surface microstructures with fine domains, flake-like domains, and dendrite structuring, 'bee-structures' with wavy patterns several micrometers in diameter and tens of nanometers in height are commonly seen in other binders. Controversy exists regarding the chemical origin of the 'bee-structures', which has been related to the asphaltene fraction, the metal content, or the crystallizing waxes in bitumen. The rich chemistry of bitumen can result in complicated intermolecular associations such as coprecipitation of wax and metalloporphyrins in asphaltenes. Therefore, it is the molecular interactions among the different chemical components in bitumen, rather than a single chemical fraction, that are responsible for the evolution of bitumen's diverse microstructures, including the 'bee-structures'. Mechanisms such as curvature elasticity and surface wrinkling that explain the rippled structures observed in polymer crystals might be responsible for the formation of 'bee-structures' in bitumen. Despite the progress made on morphological characterization of bitumen using AFM, the fundamental question whether the microstructures observed on bitumen surfaces represent its bulk structure remains to be addressed. In addition

  12. Nucleation and initial growth of atomic layer deposited titanium oxide determined by spectroscopic ellipsometry and the effect of pretreatment by surface barrier discharge

    Energy Technology Data Exchange (ETDEWEB)

    Cameron, David C., E-mail: dccameron@mail.muni.cz [R& D Centre for Low-Cost Plasma and Nanotechnology Surface Modification, Masaryk University, Kotlářská 267/2, 611 37 Brno (Czech Republic); Krumpolec, Richard, E-mail: richard.krumpolec@fmph.uniba.sk [Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University, Mlynská dolina, 842 4 Bratislava (Slovakia); Ivanova, Tatiana V., E-mail: tatiana.ivanova@lut.fi [ASTRaL team, Laboratory of Green Chemistry, Lappeenranta University of Technology, Sammonkatu 12, 50130 Mikkeli (Finland); Homola, Tomáš, E-mail: tomas.homola@mail.muni.cz [R& D Centre for Low-Cost Plasma and Nanotechnology Surface Modification, Masaryk University, Kotlářská 267/2, 611 37 Brno (Czech Republic); Černák, Mirko, E-mail: cernak@physics.muni.cz [R& D Centre for Low-Cost Plasma and Nanotechnology Surface Modification, Masaryk University, Kotlářská 267/2, 611 37 Brno (Czech Republic)

    2015-08-01

    Highlights: • Spectroscopic ellipsometry shows initial nucleation and growth process in atomic layer deposited titanium dioxide. • Quantum confinement effects were used to measure evolution of crystallite size. • Crystallite surface density can be extracted from ellipsometric surface roughness data and crystallite size. • Pretreatment of silicon substrates by diffuse coplanar surface barrier discharge has only minor effects on titanium dioxide film nucleation and growth. - Abstract: This paper reports on the use of spectroscopic ellipsometry to characterise the initial nucleation stage of the atomic layer deposition of the anatase phase of titanium dioxide on silicon substrates. Careful control and analysis of the ellipsometric measurements enables the determination of the evolution of crystallite diameter and surface density in the nucleation stage before a continuous film is formed. This growth behaviour is in line with atomic force microscopy measurements of the crystallite size. The crystallite diameter is a linear function of the number of ALD cycles with a slope of approximately 1.7 Å cycle{sup −1} which is equivalent to a layer growth rate of 0.85 Å cycle{sup −1} consistent with a ripening process which increases the crystallite size while reducing their density. The crystallite density decreases from ∼3 × 10{sup 17} m{sup −3} in the initial nucleation stages to ∼3 × 10{sup 15} m{sup −3} before the film becomes continuous. The effect of exposing the substrate to a diffuse coplanar surface barrier discharge in an air atmosphere before deposition was measured and only small differences were found: the plasma treated samples were slightly rougher in the initial stages and required a greater number of cycles to form a continuous film (∼80) compared to the untreated films (∼50). A thicker layer of native oxide was found after plasma treatment.

  13. Spectroscopic properties of MgH2, MgD2, and MgHD calculated from a new ab initio potential energy surface.

    Science.gov (United States)

    Li, Hui; Le Roy, Robert J

    2007-07-19

    A three-dimensional potential energy surface for the ground electronic state of MgH2 has been constructed from 9030 symmetry-unique ab initio points calculated using the icMRCI+Q method with aug-cc-pVnZ basis sets for n=3, 4, and 5, with core-electron correlation calculated at the MR-ACPF level of theory using cc-pCVnZ basis sets, with both calculations being extrapolated to the complete basis set limit. Calculated spectroscopic constants of MgH2 and MgD2 are in excellent agreement with recent experimental results: for four bands of MgH2 and one band of MgD2 the root-mean-square (rms) band origin discrepancies were only 0.44 and 0.06 cm(-1), respectively, and the rms relative discrepancies in the inertial rotational constants (B[v]) were only 0.0196% and 0.0058%, respectively. Spectroscopic constants for MgHD were predicted using the same potential surface.

  14. Facet Model and Mathematical Morphology for Surface Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Abidi, B.R.; Goddard, J.S.; Hunt, M.A.; Sari-Sarraf, H.

    1999-11-13

    This paper describes an algorithm for the automatic segmentation and representation of surface structures and non-uniformities in an industrial setting. The automatic image processing and analysis algorithm is developed as part of a complete on-line web characterization system of a papermaking process at the wet end. The goal is to: (1) link certain types of structures on the surface of the web to known machine parameter values, and (2) find the connection between detected structures at the beginning of the line and defects seen on the final product. Images of the pulp mixture (slurry), carried by a fast moving table, are obtained using a stroboscopic light and a CCD camera. This characterization algorithm succeeded where conventional contrast and edge detection techniques failed due to a poorly controlled environment. The images obtained have poor contrast and contain noise caused by a variety of sources. After a number of enhancement steps, conventional segmentation methods still f ailed to detect any structures and are consequently discarded. Techniques tried include the Canny edge detector, the Sobel, Roberts, and Prewitt's filters, as well as zero crossings. The facet model algorithm, is then applied to the images with various parameter settings and is found to be successful in detecting the various topographic characteristics of the surface of the slurry. Pertinent topographic elements are retained and a filtered image computed. Carefully tailored morphological operators are then applied to detect and segment regions of interest. Those regions are then selected according to their size, elongation, and orientation. Their bounding rectangles are computed and represented. Also addressed in this paper are aspects of the real time implementation of this algorithm for on-line use. The algorithm is tested on over 500 images of slurry and is found to segment and characterize nonuniformities on all 500 images.

  15. Characterization of Floating Surface Layers of Lipids and Lipopolymers by Surface-Sensitive Scattering

    Science.gov (United States)

    Krüger, Peter; Lösche, Mathias

    Nanotechnology and molecular (bio-)engineering are making ever deepening inroads into everybodys daily life. Physicochemical and biotechnological achievements in the design of physiologically active supramolecular assemblies have brought about the quest for their submolecular-level characterization. We employ surface-sensitive scattering techniques for the investigation of planar lipid membranes - floating monolayers on aqueous surfaces - to correlate structural, functional and dynamic aspects of biomembrane models. This chapter surveys recent work on the submolecular structure of floating phospholipid monolayers - where the advent of third-generation synchrotron X-ray sources has driven the development of realistic, submolecular-scale quasi-chemical models - as well as of more complex systems: cation binding to anionic lipid surfaces; conformational changes of lipopolymers undergoing phase transitions; the conformational organization of phosphatidylinositol and phosphatidylinositides, as examples of physiologically important lipids; and the adsorption of peptides (neuropeptide Y, NPY) or solvents (dimethylsulfoxide, DMSO) onto phospholipid surface layers.

  16. Fast Characterization of Moving Samples with Nano-Textured Surfaces

    CERN Document Server

    Madsen, Morten Hannibal; Zalkovskij, Maksim; Karamehmedović, Mirza; Garnæs, Jørgen

    2015-01-01

    We characterize nano-textured surfaces by optical diffraction techniques using an adapted commercial light microscope with two detectors, a CCD camera and a spectrometer. The acquisition and analyzing time for the topological parameters height, width, and sidewall angle is only a few milliseconds of a grating. We demonstrate that the microscope has a resolution in the nanometer range, also in an environment with many vibrations, such as a machine floor. Furthermore, we demonstrate an easy method to find the area of interest with the integrated CCD camera.

  17. Microanalytical characterization of surface decoration in Majolica pottery

    Energy Technology Data Exchange (ETDEWEB)

    Padilla, R. [Centro de Aplicaciones Tecnologicas y Desarrollo Nuclear (CEADEN), Havana (Cuba); Schalm, O. [Micro and Trace Analysis Center, University of Antwerp (Belgium); Janssens, K. [Micro and Trace Analysis Center, University of Antwerp (Belgium); Arrazcaeta, R. [Gabinete de Arqueologia, Oficina del Historiador de la Ciudad de la Habana (OHCH) (Cuba); Espen, P. van [Micro and Trace Analysis Center, University of Antwerp (Belgium)]. E-mail: piet.vanespen@ua.ac.be

    2005-04-11

    This paper presents the results of the characterization of the surface finishing works in archaeological pottery fragments belonging to several Majolica types. The homogeneity, thickness and inclusions of both ground glaze and color decorations were, among other characteristics, inspected by scanning electron microscopy X-ray analysis (SEM-EDX). The identification of the main constituents in the decoration motifs was performed by means of scanning micro X-ray fluorescence analysis. Additionally, compositional classification based on non-destructive quantitative analysis of the ground glaze was performed.

  18. Characterization of surface EMG signals using improved approximate entropy

    Institute of Scientific and Technical Information of China (English)

    CHEN Wei-ting; WANG Zhi-zhong; REN Xiao-mei

    2006-01-01

    An improved approximate entropy (ApEn) is presented and applied to characterize surface electromyography (sEMG)signals. In most previous experiments using nonlinear dynamic analysis, this certain processing was often confronted with the problem of insufficient data points and noisy circumstances, which led to unsatisfactory results. Compared with fractal dimension as well as the standard ApEn, the improved ApEn can extract information underlying sEMG signals more efficiently and accurately. The method introduced here can also be applied to other medium-sized and noisy physiological signals.

  19. Surface characterization of silver-doped bioactive glass.

    Science.gov (United States)

    Vernè, E; Di Nunzio, S; Bosetti, M; Appendino, P; Brovarone, C Vitale; Maina, G; Cannas, M

    2005-09-01

    A bioactive glass belonging to the system SiO(2)-CaO-Na(2)O was doped with silver ions by ion exchange in molten salts as well as in aqueous solution. The ion exchange in the solution was done to check if it is possible to prepare an antimicrobial material using a low silver content. The doped glass was characterized by means of X-ray diffraction, SEM observation, EDS analysis, bioactivity test (soaking in a simulated body fluid), leaching test (GFAAS analyses) and cytotoxicity test. It is demonstrated that these surface silver-doped glasses maintain, or even improve, the bioactivity of the starting glass. The measured quantity of released silver into simulated body fluid compares those reported in literature for the antibacterial activity and the non-cytotoxic effect of silver. Cytotoxicity tests were carried out to understand the effect of the doped surfaces on osteogenic cell adhesion and proliferation.

  20. Surface Characterization of Glass Fiber by Inverse Gas Chromatography

    Institute of Scientific and Technical Information of China (English)

    HUANG Xiaohua; LI Bin; SHI Baoli; GUO Xuefei; JIA Lina

    2008-01-01

    The surface properties of glass fiber were quantificationally analyzed by inverse gas chromatography (IGC). Five n-alkanes (C6, C7, C8, C9, and C10) were chosen as apolar probes to characterize the dispersive component of surface free energy. Trichloromethane (CHCl3), acetone,and tetrahydrofuran (THF) were chosen as polar probes to detect the Lewis acid-base parameters. It is found that the dispersive components of free energy are 32.3, 30.5, 27.5, and 26.9 Mj/m2 at 70,80, 90, and 100 ℃, respectively. The Lewis acidic number Ka of the glass fiber is 0.512 4, and the basic number Kb is 2.862. The results mean the glass fiber is a Lewis basic material.

  1. Characterization of Flexible RF Microcoil Dedicated to Surface Mri

    CERN Document Server

    Woytasik, M; Raynaud, J -S; Poirier-Quinot, M; Dufour-Gergam, E; Grandchamp, J -P; Darrasse, L; Robert, P; Gilles, J -P; Martincic, E; Girard, O

    2007-01-01

    In Magnetic Resonance Imaging (MRI), to achieve sufficient Signal to Noise Ratio (SNR), the electrical performance of the RF coil is critical. We developed a device (microcoil) based on the original concept of monolithic resonator. This paper presents the used fabrication process based on micromoulding. The dielectric substrates are flexible thin films of polymer, which allow the microcoil to be form fitted to none-plane surface. Electrical characterizations of the RF coils are first performed and results are compared to the attempted values. Proton MRI of a saline phantom using a flexible RF coil of 15 mm in diameter is performed. When the coil is conformed to the phantom surface, a SNR gain up to 2 is achieved as compared to identical but planar RF coil. Finally, the flexible coil is used in vivo to perform MRI with high spatial resolution on a mouse using a small animal dedicated scanner operating at in a 2.35 T.

  2. Theoretical characterization of formamide on the inner surface of montmorillonite

    Science.gov (United States)

    Shi, Jing; Lou, Zhaoyang; Yang, Mingli; Zhang, Yao; Liu, Houbin; Meng, Yingfeng

    2014-06-01

    Density functional theory calculations were performed to characterize the low-lying structures of formamide (FA) and protonated formamide (FAH) in the interlayer space of montmorillonite (MMT). The interactions among FA/FAH, H2O, Na+, and the inner surface of MMT were systematically analyzed. The carbonyl-O of FA/FAH has strong coulomb interaction with Na+, while its amide-H forms hydrogen bonds (HBs) with water and MMT surface. The adsorption of FA is promoted by H2O, which exhibits a cooperative adsorption effect by enhancing the FA-Na+ coulomb interaction and by forming HBs with FA. Our study reveals the structural basis of FA/FAH as an intercalator for MMT splitting.

  3. Formation and characterization of infrared absorbing copper oxide surfaces

    Science.gov (United States)

    Arslan, Burcu; Demirci, Gökhan; Erdoğan, Metehan; Karakaya, İshak

    2017-04-01

    Copper oxide formation has been investigated to combine the advantages of producing different size and shapes of coatings that possess good light absorbing properties. An aqueous blackening solution was investigated and optimum composition was found as 2.5 M NaOH and 0.225 M NaClO to form velvet copper oxide films. A two-step oxidation mechanism was proposed for the blackening process by carefully examining the experimental results. Formation of Cu2O was observed until the entire copper surface was covered at first. In the second step, Cu2O surface was further oxidized to CuO until the whole Cu2O surface was covered by CuO. Therefore, blackened copper surfaces consisted of Cu2O/CuO duplex oxides. Characterization of the coatings were performed in terms of microstructure, phase analysis, chemical state, infrared specular and total reflectivity by SEM, XRD, XPS, FTIR and UV-vis spectrophotometry, respectively.

  4. Molecular layer deposition of APTES on silicon nanowire biosensors: Surface characterization, stability and pH response

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Yuchen [Department of Electrical Engineering, University of Texas at Dallas, Richardson, TX 75080 (United States); Huang, Jie [Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, TX 75080 (United States); Zang, Pengyuan [Department of Electrical Engineering, University of Texas at Dallas, Richardson, TX 75080 (United States); Kim, Jiyoung [Department of Materials Science and Engineering, University of Texas at Dallas, Richardson, TX 75080 (United States); Hu, Walter, E-mail: walter.hu@utdallas.edu [Department of Electrical Engineering, University of Texas at Dallas, Richardson, TX 75080 (United States)

    2014-12-15

    Graphical abstract: - Abstract: We report the use of molecular layer deposition (MLD) for depositing 3-aminopropyltriethoxysilane (APTES) on a silicon dioxide surface. The APTES monolayer was characterized using spectroscopic ellipsometry, contact angle goniometry, and atomic force microscopy. Effects of reaction time of repeating pulses and simultaneous feeding of water vapor with APTES were tested. The results indicate that the synergistic effects of water vapor and reaction time are significant for the formation of a stable monolayer. Additionally, increasing the number of repeating pulses improved the APTES surface coverage but led to saturation after 10 pulses. In comparing MLD with solution-phase deposition, the APTES surface coverage and the surface quality were nearly equivalent. The hydrolytic stability of the resulting films was also studied. The results confirmed that the hydrolysis process was necessary for MLD to obtain stable surface chemistry. Furthermore, we compared the pH sensing results of Si nanowire field effect transistors (Si NWFETs) modified by both the MLD and solution methods. The highly repeatable pH sensing results reflected the stability of APTES monolayers. The results also showed an improved pH response of the sensor prepared by MLD compared to the one prepared by the solution treatment, which indicated higher surface coverage of APTES.

  5. Molecular layer deposition of APTES on silicon nanowire biosensors: Surface characterization, stability and pH response

    Science.gov (United States)

    Liang, Yuchen; Huang, Jie; Zang, Pengyuan; Kim, Jiyoung; Hu, Walter

    2014-12-01

    We report the use of molecular layer deposition (MLD) for depositing 3-aminopropyltriethoxysilane (APTES) on a silicon dioxide surface. The APTES monolayer was characterized using spectroscopic ellipsometry, contact angle goniometry, and atomic force microscopy. Effects of reaction time of repeating pulses and simultaneous feeding of water vapor with APTES were tested. The results indicate that the synergistic effects of water vapor and reaction time are significant for the formation of a stable monolayer. Additionally, increasing the number of repeating pulses improved the APTES surface coverage but led to saturation after 10 pulses. In comparing MLD with solution-phase deposition, the APTES surface coverage and the surface quality were nearly equivalent. The hydrolytic stability of the resulting films was also studied. The results confirmed that the hydrolysis process was necessary for MLD to obtain stable surface chemistry. Furthermore, we compared the pH sensing results of Si nanowire field effect transistors (Si NWFETs) modified by both the MLD and solution methods. The highly repeatable pH sensing results reflected the stability of APTES monolayers. The results also showed an improved pH response of the sensor prepared by MLD compared to the one prepared by the solution treatment, which indicated higher surface coverage of APTES.

  6. Vibrational spectroscopic (FT-IR, FT-Raman) studies, Hirshfeld surfaces analysis, and quantum chemical calculations of m-acetotoluidide and m-thioacetotoluidide

    Science.gov (United States)

    Śmiszek-Lindert, Wioleta Edyta; Chełmecka, Elżbieta; Góralczyk, Stefan; Kaczmarek, Marian

    2017-01-01

    Theoretical calculations of the m-acetotoluidide and m-thioacetotoluidide isolated molecules were performed by using density functional theory (DFT) method at B3LYP/6-311++G (d,p) and B3LYP/6-311++G (3df,2pd) basis set levels. The Hirshfeld surfaces analysis and FT-IR and FT-Raman spectroscopy studies have been reported. The geometrical parameters of the title amide and thioamide are in a good agreement with the XRD experiment. The vibrational frequencies were calculated and scaled, and subsequently values have been compared with the experimental Infrared and Raman spectra. The observed and calculated frequencies are found to be in good agreement. The analysis of the Hirshfeld surface has been well correlated to the spectroscopic studies. Additionally, the highest occupied molecular orbital energy (EHOMO), lowest unoccupied molecular orbital energy (ELUMO) and the energy gap between EHOMO and ELUMO (ΔEHOMO-LUMO) have been calculated.

  7. Surface characterization and stability of an epoxy resin surface modified with polyamines grafted on polydopamine

    Energy Technology Data Exchange (ETDEWEB)

    Schaubroeck, David, E-mail: David.Schaubroeck@elis.ugent.be [Center for Microsystems Technology (CMST), imec and Ghent University, Technologiepark 914A, B-9052 Ghent (Belgium); Vercammen, Yannick; Van Vaeck, Luc [Biomolecular and Analytical Mass Spectrometry, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk (Belgium); Vanderleyden, Els; Dubruel, Peter [Polymer Chemistry and Biomaterials Research Group, Ghent University, Krijgslaan 281 S4 bis, B-9000 Ghent (Belgium); Vanfleteren, Jan [Center for Microsystems Technology (CMST), imec and Ghent University, Technologiepark 914A, B-9052 Ghent (Belgium)

    2014-06-01

    This paper reports on polydopamine and polyamine surface modifications of an etched epoxy cresol novolac (ECN) resin using the ‘grafting to’ method. Three different polyamines are used for the grafting reactions: branched polyethyleneimine (B-PEI), linear polyethyleneimine (L-PEI) and diethylenetriamine (DETA). These modifications are compared to control materials prepared via direct deposition of polyamines. The stability of the modifications toward a concentrated hydrochloric acid (HCl) environment is evaluated. The modified surfaces are characterized with scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and time-of-flight static secondary ion mass spectroscopy (TOF-S-SIMS).

  8. Electrochemical and spectroscopic characterization of lithium titanate spinel Li{sub 4}Ti{sub 5}O{sub 12}

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, Holger; Maire, Pascal [Paul Scherrer Institut, Electrochemistry Laboratory, Section Electrochemical Energy Storage, CH-5232 Villigen PSI (Switzerland); Novak, Petr, E-mail: petr.novak@psi.ch [Paul Scherrer Institut, Electrochemistry Laboratory, Section Electrochemical Energy Storage, CH-5232 Villigen PSI (Switzerland)

    2011-10-30

    Herein we describe electrochemical and spectroscopic properties of lithium titanate spinel as well as an easy method based on colorimetry to determine the lithium content of electrodes containing lithium titanate spinel as active material. Raman microspectrometry measurements have been performed to follow lithium insertion into and extraction from the active material, respectively. The Raman signals display a pronounced fading of intensity already at low levels of lithium intercalation and disappear at a SOC higher than {approx}10%. However, the colorimetric method can be used up to a SOC of 50%.

  9. The CoRoT-GES Collaboration. Improving Red Giants spectroscopic surface gravity and abundances with asteroseismology

    CERN Document Server

    Valentini, M; Miglio, A; Montalbán, J; Rodrigues, T; Mosser, B; Anders, F

    2016-01-01

    Nowadays large spectroscopic surveys, like the Gaia-ESO Survey (GES), provide unique stellar databases for better investigating the formation and evolution of our Galaxy. Great attention must be paid to the accuracy of the basic stellar properties derived: large uncertainties in stellar parameters lead to large uncertainties in abundances, distances and ages. Asteroseismology has a key role in this context: when seismic information is combined with information derived from spectroscopic analysis, highly precise constraints on distances, masses, extinction and ages of Red Giants can be obtained. In the light of this promising joint-action, we started the CoRoT-GES collaboration. We present a set of 1,111 CoRoT stars, observed by GES from December 2011 to July 2014, these stars belong to the CoRoT field LRc01, pointing at the inner Galactic Disk. Among these stars, 534 have reliable global seismic parameters. By combining seismic informations and spectroscopy, we derived precise stellar parameters, ages, kinema...

  10. Structural and Spectroscopic Characterization of A Nanosized Sulfated TiO2 Filler and of Nanocomposite Nafion Membranes

    Directory of Open Access Journals (Sweden)

    Valentina Allodi

    2016-03-01

    Full Text Available A large number of nano-sized oxides have been studied in the literature as fillers for polymeric membranes, such as Nafion®. Superacidic sulfated oxides have been proposed and characterized. Once incorporated into polymer matrices, their beneficial effect on peculiar membrane properties has been demonstrated. The alteration of physical-chemical properties of composite membranes has roots in the intermolecular interaction between the inorganic filler surface groups and the polymer chains. In the attempt to tackle this fundamental issue, here we discuss, by a multi-technique approach, the properties of a nanosized sulfated titania material as a candidate filler for Nafion membranes. The results of a systematic study carried out by synchrotron X-ray diffraction, transmission electron microscopy, thermogravimetry, Raman and infrared spectroscopies are presented and discussed to get novel insights about the structural features, molecular properties, and morphological characteristics of sulphated TiO2 nanopowders and composite Nafion membranes containing different amount of sulfated TiO2 nanoparticles (2%, 5%, 7% w/w.

  11. Spectroscopic characterization of dissolved organic matter derived from different biochars and their polycylic aromatic hydrocarbons (PAHs) binding affinity.

    Science.gov (United States)

    Tang, Jianfeng; Li, Xinhu; Luo, Yan; Li, Gang; Khan, Sardar

    2016-06-01

    In recent years, biochar has received a great attention due to its high application in different sectors of environment. The feasibility of biochar applications is depended on its physical and chemical properties and biochar-derived dissolved organic matter (DOM) characteristics. This study was conducted to investigate the spectroscopic characteristics of biochar-derived DOM and its binding capacity of hydrophobic organic chemicals (HOCs). DOM solutions were isolated from five different biochars prepared through pyrolysis and analyzed for dissolved organic carbon (DOC) contents. The optical analysis with UV-visible absorption and excitation-emission matrix (EEM) fluorescence spectroscopes and DOC water distribution coefficient (KDOC) were calculated in the presence of PAHs and DOM. The DOC contents and the estimated aromaticity (SUVA254) were different for selected biochars. The DOM derived from soybean straw biochar (SBBC) showed the highest DOC contents followed by rice straw biochar (RSBC). The SBBC and RSBC peak position in the fluorescence excitation/emission matrix at longer wavelength corresponded to the peak position of other three biochars indicating that SBBC and RSBC had relatively higher degree of humification. This was well correlated with the observed KDOC values, suggesting that the KDOC value(')s dominant factor was the degree of biochar-derived DOM humification. The results of this study indicate that the optical analysis may provide valuable information regarding the characteristics of biochar-derived DOM and its application as environmental amendments for minimization of toxic organic compounds.

  12. Chemical surface modification of porous silicon with palladium and characterizations

    Energy Technology Data Exchange (ETDEWEB)

    Kanungo, J.; Maji, S.; Saha, H. [IC Design and Fabrication Centre, Department of Electronics and Telecommunication Engineering, Jadavpur University, Kolkata 700032 (India); Basu, S., E-mail: sukumar_basu@yahoo.co.u [IC Design and Fabrication Centre, Department of Electronics and Telecommunication Engineering, Jadavpur University, Kolkata 700032 (India)

    2010-03-15

    Porous silicon (PS) was formed on p-type crystalline silicon of (1 0 0) orientation and 2-5 OMEGA cm resistivity by the electrochemical anodization method using HF and ethanol as the electrolyte. Adjusting the current density and the HF concentration in the electrolyte the porosity of the samples were varied from 40% to 60%. The porous silicon surface was modified with PdCl{sub 2} solution by a low cost chemical method. Both the unmodified and the modified PS were thoroughly characterized by the EDAX analysis, the digital X-ray image mapping and the XPS study. Electrical characteristics were performed by the I-V measurements for both the lateral and the sandwich structures using Al metal contact. The I-V characteristics of the modified PS for all the porosity were more reproducible compared to the unmodified PS surfaces. It was further observed that the conductivity increased with the increasing porosity for the Pd-modified surfaces whereas it decreased for the unmodified PS.

  13. A high throughput approach to quantify protein adsorption on combinatorial metal/metal oxide surfaces using electron microprobe and spectroscopic ellipsometry

    Science.gov (United States)

    Byrne, T.; Lohstreter, L.; Filiaggi, M. J.; Bai, Zhijun; Dahn, J. R.

    2008-09-01

    Although metallic biomaterials are widely used, systematic studies of protein adsorption onto such materials are generally lacking. Combinatorial binary films of Al 1-xTi x and Al 1-xNb x (0 ⩽ x ⩽ 1) and corresponding pure element films were produced on glass substrates using a unique magnetron sputtering technique. Fibrinogen and albumin adsorption amounts were measured by wavelength-dispersive spectroscopy (WDS) and spectroscopic ellipsometry (SE) equipment, both high throughput techniques with automated motion stage capabilities. X-ray diffraction revealed that the binary films have crystalline phases present near the ends of the compositional gradient with an amorphous region throughout the interior of the gradient. X-ray photoelectron spectroscopy provided the surface chemistry along the binary films and showed that Al 2O 3 preferentially formed at the surface. Protein adsorption onto these films was found to be closely correlated to the alumina surface fraction, with high alumina content at the surface leading to low amounts of adsorbed fibrinogen and albumin. Protein adsorption amounts obtained with WDS and SE were in excellent agreement for all films. This suggests that this combinatorial materials approach combined with these state-of-the-art, automated high throughput instruments provides a novel way to accurately monitor protein adsorption taking place at the surfaces of these metal/metal oxide materials.

  14. Electrochemical synthesis and surface characterization of (pyrrole+2-methylfuran) copolymer

    Science.gov (United States)

    Djaouane, Linda; Nessark, Belkacem; Sibous, Lakhdar

    2017-02-01

    Electrochemical copolymerization of pyrrole (Py) and 2-methylfuran (2 MF) was performed on platinum and ITO substrates in acetonitrile/lithium perchlorate solution, using cyclic voltammetry method. The electrochemical behavior of the modified electrode surface by polypyrrole, poly(2-methylfuran) homopolymers and (pyrrole+2-methylfuran) copolymer was characterized by cyclic voltammetry, electrochemical impedance spectroscopy (EIS), UV-visible spectroscopy, atomic force microscopy (AFM) and scanning electron microscopy (SEM). The cyclic voltammetry shows anodic and cathodic peaks which are characteristic of the oxidation and the reduction of the formed films. The electrochemical impedance spectroscopy confirmed the results obtained by cyclic voltammetry. AFM and SEM analyses proved as well that the morphology and the electrochemical properties of the polypyrrole film are modified in the presence of 2-methylfuran.

  15. Structural, spectroscopic characterization of (E)-4-chloro-2-((4-methoxybenzylidene)amino)phenol as potential antioxidant compound

    Science.gov (United States)

    Şen, Fatih; Efil, Kürşat; Bekdemir, Yunus; Dinçer, Muharrem

    2017-01-01

    A new imine derivative, (E)-4-chloro-2-((4-methoxybenzylidene)amino)phenol has been synthesized from the reaction of 4-Anisaldehyde with benzoyl 2-Amino-4-chlorophenol. The results of a combined experimental and DFT investigations of the structural and spectroscopic properties of the title compound are given. The crystal and molecular investigations are performed by X-ray diffraction and spectral results obtained by IR, NMR and UV-Vis spectrometers. The structural geometry, vibration frequencies, 1H and 13C NMR chemical shifts, UV-Vis spectral analysis and HOMO-LUMO of molecule in the ground state have been also calculated using the density functional theory (DFT) employing B3LYP exchange correlation with the 6-311G+(d, p) basis set, and check aganist the experimental data. The stability of antioxidant at different concentrations of compound are evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical method and determined its specific absorbance properties.

  16. Spectroscopic characterization of a sample of metal-poor solar-type stars from the HARPS planet search program

    CERN Document Server

    Sousa, Sérgio G; Israelian, Garik; Lovis, C; Mayor, Michel; Silva, Pedro B; Udry, Stephane

    2010-01-01

    Stellar metallicity strongly correlates with the presence of planets and their properties. To check for new correlations between stars and the existence of an orbiting planet, we determine precise stellar parameters for a sample of metal-poor solar-type stars. This sample was observed with the HARPS spectrograph and is part of a program to search for new extrasolar planets. The stellar parameters were determined using an LTE analysis based on equivalent widths (EW) of iron lines and by imposing excitation and ionization equilibrium. The ARES code was used to allow automatic and systematic derivation of the stellar parameters. Precise stellar parameters and metallicities were obtained for 97 low metal-content stars. We also present the derived masses, luminosities, and new parallaxes estimations based on the derived parameters, and compare our spectroscopic parameters with an infra-red flux method calibration to check the consistency of our method in metal poor stars. Both methods seems to give the same effect...

  17. Surface Characterization of a Paper Web at the Wet End

    Energy Technology Data Exchange (ETDEWEB)

    Abidi, B.R.; Goddard, J.S.; Sari-Sarraf, H.

    1999-06-23

    We present an algorithm for the detection and representation of structures and non-uniformities on the surface of a paper web at the wet end (slurry). This image processing/analysis algorithm is developed as part of a complete on-line web characterization system. Images of the slurry, carried by a fast moving table, are obtained using a stroboscopic light and a CCD camera. The images have very poor contrast and contain noise from a variety of sources. Those sources include the acquisition system itself, the lighting, the vibrations of the moving table being imaged, and the scattering water from the same table's movement. After many steps of enhancement, conventional edge detection methods were still inconclusive and were discarded. The facet model algorithm, is applied to the images and is found successful in detecting the various topographic characteristics of the surface of the slurry. Pertinent topographic elements are retained and a filtered image is computed based on the general appearance and characteristics of the structures in question. Morphological operators are applied to detect and segment regions of interest. Those regions are then filtered according to their size, elongation, and orientation.Their bounding rectangles are computed and superimposed on the original image. Real time implementation of this algorithm for on-line use is also addressed in this paper. The algorithm is tested on over 500 images of slurry and is found to detect nonuniformities on all 500 images. Locating and characterizing all different size structures is also achieved on all 500 images of the web.

  18. The purple Codex Rossanensis: spectroscopic characterization and first evidence of the use of the elderberry lake in a 6th century manuscript

    CERN Document Server

    Bicchieri, Marina

    2014-01-01

    The Codex Rossanensis is a 6th century Bizantine illuminated manuscript written on purple parchment and conserved at the Museo Diocesano in Rossano Calabro, Italy. It is one of the oldest surviving illuminated manuscripts of the New Testament. The challenge of the analysis of the Codex Rossanensis lies in the lack of analytical information on the pictorial media used in the Early Middle Ages. Even though old-medieval illuminated manuscripts have been deeply studied from the historical standpoint, they have been rarely described in their material composition. This paper presents the results obtained during the measurements campaign (June 2012 - November 2013). The spectroscopic analyses performed by Raman, micro-FTIR and XRF allowed for the complete characterization of the pictorial palette, the inks, the support and the material used in a previous restoration treatment. To the author knowledge the article shows the first experimental evidence of the usage of the elderberry lake in a 6th century illuminated ma...

  19. Synthesis, spectroscopic characterization, potentiometric studies, cytotoxic studies and molecular docking studies of DNA binding of transition metal complexes with 1,1-diaminopropane-Schiff base

    Science.gov (United States)

    Alaghaz, Abdel-Nasser M. A.; El-Sayed, Badr A.; El-Henawy, Ahmed A.; Ammar, Reda A. A.

    2013-03-01

    A new series of Schiff base transition metal complexes with N,N'-bis(2-hydroxybenzylidene)-1,1-diaminopropane (H2BHBDAP) have been prepared and characterized by elemental analysis, spectroscopic and magnetic measurements. Protonation constants of Schiff base and stability constants of their binary metal complexes have been determined potentiometrically in 50% DMSO-water media at 25 °C and ionic strength 0.10 M sodium perchlorate. Quantum chemical calculations were performed with semi-empirical method to find the optimum geometry of the ligand and its complexes. Additionally in silico, the Docking studies and the calculated pharmacokinetic parameters show promising futures for application of the ligand and complexes as high potency agents for DNA binding activity.

  20. 2.2.1. Synthesis, spectroscopic characterization and crystal structure of [ReV(O2(pyz4][ReII(NOBr4(pyz] (pyz = pyrazine

    Directory of Open Access Journals (Sweden)

    Mario Pacheco, Alicia Cuevas, Javier González-Platas, Carlos Kremer*

    2015-03-01

    Full Text Available Abstract: A novel Re(V-Re(II nitrosyl complex, [Re(O2(pyz 4][Re(NOBr4(pyz] (pyz = pyrazine was prepared and characterized by X-ray diffraction, elemental analysis, infrared and ultraviolet-visible absorption spectra. This product is obtained in the initial steps of the reaction of (NBu4[Re(NOBr4(EtOH] with pyrazine. Both, the cation and the anion are mononuclear complexes. The Re(V atom in the cation is six-coordinate with four nitrogen atoms from pyrazine ligands, and two oxo ligands. The Re(II anion is also six-coordinate, with four bromide ligands, a linear nitrosyl group and one nitrogen from pyrazine. The spectroscopic studies are discussed and compared with those already reported separately for the cation and the anion. Supporting information: X-Ray (CIF file

  1. Interfacial characterization and analytical applications of chemically-modified surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jianhong [Iowa State Univ., Ames, IA (United States)

    1998-02-23

    The goal of this work is to explore several new strategies and approaches to the surface modification and the microscopic characterization of interfaces in the areas mainly targeting sensor technologies that are of interest to environmental control or monitoring, and scanning probe microscopies techniques that can monitor interfacial chemical reactions in real time. Centered on the main theme, four specific topics are presented as four chapters in this dissertation following the general introduction. Chapter 1 describes the development of two immobilization schemes for covalently immobilizing fluoresceinamine at cellulose acetate and its application as a pH sensing film. Chapter 2 investigates the applicability of SFM to following the base-hydrolysis of a dithio-bis(succinimidylundecanoate) monolayer at gold in situ. Chapter 3 studies the mechanism for the accelerated rate of hydrolysis of the dithio-bis(succinimidylundecanoate) monolayer at Au(111) surface. Chapter 4 focuses on the development of an electrochemical approach to the elimination of chloride interference in Chemical Oxygen Demand (COD) analysis of waste water. The procedures, results and conclusions are described in each chapter. This report contains the introduction, references, and general conclusions. Chapters have been processed separately for inclusion on the data base. 95 refs.

  2. Surface characterization after subaperture reactive ion beam etching

    Energy Technology Data Exchange (ETDEWEB)

    Miessler, Andre; Arnold, Thomas; Rauschenbach, Bernd [Leibniz-Institut fuer Oberflaechenmodifizierung (IOM), Leipzig (Germany)

    2010-07-01

    In usual ion beam etching processes using inert gas (Ar, Xe, Kr..) the material removal is determined by physical sputtering effects on the surface. The admixture of suitable gases (CF{sub 4}+O{sub 2}) into the glow discharge of the ion beam source leads to the generation of reactive particles, which are accelerated towards the substrate where they enhance the sputtering process by formation of volatile chemical reaction products. During the last two decades research in Reactive Ion Beam Etching (RIBE) has been done using a broad beam ion source which allows the treatment of smaller samples (diameter sample < diameter beam). Our goal was to apply a sub-aperture Kaufman-type ion source in combination with an applicative movement of the sample with respect to the source, which enables us to etch areas larger than the typical lateral dimensions of the ion beam. Concerning this matter, the etching behavior in the beam periphery plays a decisive role and has to be investigated. We use interferometry to characterize the final surface topography and XPS measurements to analyze the chemical composition of the samples after RIBE.

  3. Surface Material Characterization from Multi-band Optical Observations

    Science.gov (United States)

    Hall, D.

    2010-09-01

    Ground-based optical and radar sites routinely acquire resolved images of satellites. These resolved images provide the means to construct accurate wire-frame models of the observed body, as well as an understanding of its orientation as a function of time. Unfortunately, because such images are typically acquired in a single spectral band, they provide little information on the types of materials covering the satellite's various surfaces. Detailed surface material characterization generally requires spectrometric and/or multi-band photometric measurements. Fortunately, many instruments provide such multi-band information (e.g., spectrographs and multi-channel photometers). However, these sensors often measure the brightness of the entire satellite, with no spatial resolution at all. Because such whole-body measurements represent a summation of contributions from many reflecting surfaces, an ―un-mixing‖ or inversion process must be employed to determine the materials covering each of the satellite's individual sub-components. The first section of this paper describes the inversion theory required to retrieve satellite surface material properties from temporal sequences of whole-body multi-band brightness measurements. The inversion requires the following as input: 1) a set of multi-band measurements of a satellite's reflected-sunlight brightness, 2) the satellite's wire-frame model, including each major component capable of reflecting sunlight, 3) the satellite's attitude, specifying the body’s orientation at the time of each multi-band measurement, and 4) a database of bi-directional reflection distribution functions for a set of candidate surface materials. As output, the inversion process yields estimates of the fraction of each major satellite component covered by each candidate material. The second section of the paper describes several tests of the method by applying it to simulated multi-band observations of a cubical satellite with different materials

  4. Spectroscopic characterization of lycopene extract from Lycopersicum esculentum (Tomato) and its evaluation as a chemopreventive agent against experimental hepatocarcinogenesis in mice.

    Science.gov (United States)

    Gupta, Prachi; Bansal, Mohinder Pal; Koul, Ashwani

    2013-03-01

    The present study was designed to characterize the lycopene extract (LycT) prepared from tomatoes (Lycopersicum esculentum) and then to evaluate its chemopreventive efficacy in N-diethylnitrosamine (NDEA)-induced experimental hepatocarcinogenesis in female Balb/c mice. The extraction of lycopene was carried out using hexane/acetone/ethanol as an extracting medium and then characterized by ultraviolet-visible, nuclear magnetic resonance and Fourier transform infrared spectroscopy. Chemopreventive efficacy of characterized LycT in vivo was evaluated in terms of hepatic tumour incidence, multiplicity, burden, hepatosomatic index and animal survival rate. Results indicated that average lycopene content of the tomato was 11.6-14 mg/kg tomato weight. Spectroscopic data confirmed the structural characteristics of lycopene in the extract. In the animal study, reduction in tumour incidence (42.05%), tumour burden (1.39) and tumour multiplicity (3.42) was observed upon LycT pretreatment to NDEA-treated animals. Histopathological analysis unravelled that the increased survival rate in LycT + NDEA-treated animals was due to the delay in the formation of aggressive tumour nodules. These observations indicate that lycopene seems to be an able candidate for chemoprevention in hepatocarcinogenesis resulting from NDEA insults.

  5. Synchrotron Spectroscopic Studies of the Reaction of Cleaved Pyrite ( {FeS2}) Surfaces with Cr(VI) Solutions

    Science.gov (United States)

    Doyle, C. S.; Kendelewicz, T.; Bostick, B. C.; Brown, G. E.

    2002-12-01

    Pyrite is one of the most common sulfide ores, and the separation of valuable sulfide minerals from it has been an area of considerable interest for a long time. This extraction has led to a large quantity of pyrite waste, typically remaining in mine tailings piles which can interact with oxygen and surface water. The oxidation of pyrite under these conditions leads to the commonly known environmental problem of acid mine drainage, with acidification of surface waters, and the release of potentially toxic metals remaining within the pyrite matrix. A microscopic understanding of this oxidation process is extremely important and has been the aim of a number of studies. We apply the methods of synchrotron based surface science to this problem, utilizing surface sensitive photoemission and X-ray absorption spectroscopy to study the surface species present on the pyrite surface at the initial stages of oxidation. We have reacted pyrite surfaces with solutions containing chromate. Chromium exists in solution in two principal valence states, trivalent Cr(III) and hexavalent Cr(VI). Hexavalent chromium is itself considered an environmental problem due to its high toxicity and solubility, and thus mobility, whilst trivalent chromium is much less toxic and relatively insoluble. Hexavalent chromate is a strong oxidizing agent, and will react rapidly with the pyrite surface allowing the identification of oxidized iron and sulfur surface species. The possibility of using pyrite as a means of reducing chromate, and at the same time using chromate to passivate the pyrite surface to further oxidation through the buildup of a non-reactive iron-chromium (oxy)hydroxide layer will be investigated. The work was performed on rods cut from a natural pyrite single crystal from the Logroño region of Spain. The rods were then fractured over a reaction vessel, producing a fresh (100) surface for each experiment. The pyrite surfaces were reacted with 50 μM Cr(VI) solutions for 5 minutes at

  6. Structural characterization of surface glycans from Clostridium difficile.

    Science.gov (United States)

    Reid, Christopher W; Vinogradov, Evgeny; Li, Jianjun; Jarrell, Harold C; Logan, Susan M; Brisson, Jean-Robert

    2012-06-01

    Whole-cell high-resolution magic angle spinning (HR-MAS) NMR was employed to survey the surface polysaccharides of a group of clinical and environmental isolates of Clostridium difficile. Results indicated that a highly conserved surface polysaccharide profile among all strains studied. Multiple additional peaks in the anomeric region were also observed which prompted further investigation. Structural characterization of the isolated surface polysaccharides from two strains confirmed the presence of the conserved water soluble polysaccharide originally described by Ganeshapillai et al. which was composed of a hexaglycosyl phosphate repeat consisting of [→6)-β-D-Glcp-(1-3)-β-D-GalpNAc-(1-4)-α-D-Glcp-(1-4)-[β-D-Glcp(1-3]-β-D-GalpNAc-(1-3)-α-D-Manp-(1-P→]. In addition, analysis of phenol soluble polysaccharides revealed a similarly conserved lipoteichoic acid (LTA) which could be detected on whole cells by HR-MAS NMR. Conventional NMR and mass spectrometry analysis indicated that the structure of this LTA consisted of the repeat unit [→6)-α-D-GlcpNAc-(1-3)-[→P-6]-α-D-GlcpNAc-(1-2)-D-GroA] where GroA is glyceric acid. The repeating units were linked by a phosphodiester bridge between C-6 of the two GlcNAc residues (6-P-6). A minor component consisted of GlcpN-(1-3) instead of GlcpNAc-(1-3) in the repeat unit. Through a 6-6 phosphodiester bridge this polymer was linked to →6)-β-D-Glcp-(1-6)-β-D-Glcp-(1-6)-β-D-Glcp-(1-1)-Gro, with glycerol (Gro) substituted by fatty acids. This is the first report of the utility of HR-MAS NMR in the examination of surface carbohydrates of Gram positive bacteria and identification of a novel LTA structure from Clostridium difficile.

  7. State-of-the-art in analytical characterization of high purity solid samples by different spectroscopic methods

    Indian Academy of Sciences (India)

    S S Grazhulene

    2005-07-01

    Facilities and some results of several spectroscopic methods which have potential applications in the field of analysis of solid high purity substances and which have been elaborated in Russia, will be discussed in this paper. Laser nondispersive atomic fluorescence method with glow discharge cathode sputtering atomiser, may be used for trace element determination as well as a tool for the investigation of technological processes, viz. deposition of thin films. Investigations on reduction of a background level in the new hollow cathode ion source for mass-spectrometry have been carried out. Laser mass spectrometry with tandem laser mass reflectron is successfully designed and applied for gaseous impurities determination in high pure silicon with limit of detection of 10-3–10-5 ppm wt. Several results of the layer-by-layer and bulk trace analysis of solids by high resolution mass spectrometry with radio frequency powered glow discharge ion source with the limits of detection at 10-1–10-3 ppm wt will be presented here. The traditional arc and spark emission technique still finds considerable use. One of the examples considered in the paper is the analysis of metalfullerenes. To overcome the calibration problem the fluorination process inside the electrode crater using zinc fluoride has been investigated.

  8. Some new [(thione)2Au(diamine)]Cl3 complexes: synthesis, spectroscopic characterization, computational and in vitro cytotoxic studies.

    Science.gov (United States)

    Al-Maythalony, Bassem A; Monim-ul-Mehboob, M; Altaf, Muhammad; Wazeer, Mohammed I M; Isab, Anvarhusein A; Altuwaijri, Saleh; Ahmed, Ayesha; Dhuna, Vikram; Bhatia, Gaurav; Dhuna, Kshitija; Kamboj, Sukhdev Singh

    2013-11-01

    Recent advances in oncology are focused on developing new complexes of gold(III) with various ligands that show augmented anti-proliferative potential and reduced toxicity as compared to cis-platin. In this study, new Au(III) complexes of the type [(thione)2Au(diamine)]Cl3 are reported, where thione=1,3-imidazolidine-2-thione (Imt), 1,3-Diazinane-2-thione (Diaz) and diamine=1,2-diaminoethane (en), 1,3-diaminopropane (pn) or 1,4-diaminobutane (bn). The solid state IR as well as (13)C and (15)N NMR data indicate that Au(III) center is bonded via sulfur of thiocarbonyl SC site of the thiones and also chelated by the diamines from the trans side of coordinated thiones. Spectroscopic data are evaluated by comparisons with calculated data from the built and optimized structure by GAUSSIAN 09 at the RB3LYP level with LanL2DZ bases set. These new Au(III) complexes based on mixed thione and diamine ligands are very similar to the square planar structure of tetracoordinate [Au(en)2]Cl3complex. In this study, cytotoxicity data for these gold(III) complexes against C6 glioma cell lines are also reported, and the results indicate some complexes have cytotoxicity comparable to cis-platin.

  9. Spectroscopic, structural characterizations and antioxidant capacity of the chromium (III) niacinamide compound as a diabetes mellitus drug model.

    Science.gov (United States)

    Refat, Moamen S; El-Megharbel, Samy M; Hussien, M A; Hamza, Reham Z; Al-Omar, Mohamed A; Naglah, Ahmed M; Afifi, Walid M; Kobeasy, Mohamed I

    2017-02-15

    New binuclear chromium (III) niacinamide compound with chemical formula [Cr2(Nic)(Cl)6(H2O)4]·H2O was obtained upon the reaction of chromium (III) chloride with niacinamide (Nic) in methanol solvent at 60°C. The proposed structure was discussed with the help of microanalytical analyses, conductivity, spectroscopic (FT-IR and UV-vis.), magnetic calculations, thermogravimetric analyses (TG/TGA), and morphological studies (X-ray of solid powder and scan electron microscopy. The infrared spectrum of free niacinamide in comparison with its chromium (III) compound indicated that the chelation mode occurs via both nitrogen atoms of pyridine ring and primary -NH2 group. The efficiency of chromium (III) niacinamide compound in decreasing of glucose level of blood and HbA1c in case of diabetic rats was checked. The ameliorating gluconeogenic enzymes, lipid profile and antioxidant defense capacities are considered as an indicator of the efficiency of new chromium (III) compound as antidiabetic drug model.

  10. Spectroscopic, structural characterizations and antioxidant capacity of the chromium (III) niacinamide compound as a diabetes mellitus drug model

    Science.gov (United States)

    Refat, Moamen S.; El-Megharbel, Samy M.; Hussien, M. A.; Hamza, Reham Z.; Al-Omar, Mohamed A.; Naglah, Ahmed M.; Afifi, Walid M.; Kobeasy, Mohamed I.

    2017-02-01

    New binuclear chromium (III) niacinamide compound with chemical formula [Cr2(Nic)(Cl)6(H2O)4]·H2O was obtained upon the reaction of chromium (III) chloride with niacinamide (Nic) in methanol solvent at 60 °C. The proposed structure was discussed with the help of microanalytical analyses, conductivity, spectroscopic (FT-IR and UV-vis.), magnetic calculations, thermogravimetric analyses (TG/TGA), and morphological studies (X-ray of solid powder and scan electron microscopy. The infrared spectrum of free niacinamide in comparison with its chromium (III) compound indicated that the chelation mode occurs via both nitrogen atoms of pyridine ring and primary -NH2 group. The efficiency of chromium (III) niacinamide compound in decreasing of glucose level of blood and HbA1c in case of diabetic rats was checked. The ameliorating gluconeogenic enzymes, lipid profile and antioxidant defense capacities are considered as an indicator of the efficiency of new chromium (III) compound as antidiabetic drug model.

  11. Spectroscopic characterization of the alternate form of S-methylcoenzyme M reductase from Methanobacterium thermoautotrophicum (strain delta H).

    Science.gov (United States)

    Brenner, M C; Ma, L; Johnson, M K; Scott, R A

    1992-04-08

    Two forms (MR1 and MR2) of S-methylcoenzyme M reductase were purified from Methanobacterium thermoautotrophicum (strain delta H) as recently described (Rospert, S., Linder, D., Ellerman, J. and Thauer, R.K. (1990) Eur. J. Biochem. 194, 871-877). MR2 was at least 50-fold more active than MR1, independent of assay conditions. The two forms are spectroscopically similar, but not identical, by UV-visible, magnetic circular dichroism and resonance Raman spectroscopies. MR2 exhibited an EPR signal corresponding to 20% of the enzyme-bound nickel. Strong EPR signals similar to those previously assigned to Ni(I)F430 bound to methylreductase in Methanobacterium thermoautotrophicum (strain Marburg) (Albracht, S.P.J., Ankel-Fuchs, D., Bocher, R., Ellerman, J., Moll, J., Van der Zwann, J.W. and Thauer, R.K. (1988) Biochim. Biophys. Acta 955, 86-102) were observed in MR2-rich, log-phase, as well as in MR1-rich, slow-growing bacteria. Log-phase cells had dramatically different EPR spectra depending on whether they were removed from the fermenter (under gas flow) before or after cooling to 10 degrees C. EPR spectra of slow-growing cells were insensitive to harvesting conditions. The possible biological significance of the alternate form of methylreductase is discussed.

  12. Complex of manganese (II) with curcumin: Spectroscopic characterization, DFT study, model-based analysis and antiradical activity

    Science.gov (United States)

    Gorgannezhad, Lena; Dehghan, Gholamreza; Ebrahimipour, S. Yousef; Naseri, Abdolhossein; Nazhad Dolatabadi, Jafar Ezzati

    2016-04-01

    The complex formation between curcumin (Cur) and Manganese (II) chloride tetrahydrate (MnCl2.4H2O) was studied by UV-Vis and IR spectroscopy. Spectroscopic data suggest that Cur can chelate Manganese cations. A simple multi-wavelength model-based method was used to define stability constant for complexation reaction regardless of the spectra overlapping of components. Also, pure spectra and concentration profiles of all components were extracted using this method. Density functional theory (DFT) was also used to view insight into complexation mechanism. Antioxidant activity of Cur and Cur-Mn(II) complex was evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging method. Bond dissociation energy (BDE), the highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO) and Molecular electrostatic potential (MEP) of Cur and the complex also were calculated at PW91/TZ2P level of theory using ADF 2009.01 package. The experimental results show that Cur has a higher DPPH radical scavenging activity than Cur-Mn(II). This observation is theoretically justified by means of lower BDE and higher HOMO and LUMO energy values of Cur ligand as compared with those of Cur-Mn(II) complex.

  13. Characterization of the Eimeria maxima sporozoite surface protein IMP1.

    Science.gov (United States)

    Jenkins, M C; Fetterer, R; Miska, K; Tuo, W; Kwok, O; Dubey, J P

    2015-07-30

    The purpose of this study was to characterize Eimeria maxima immune-mapped protein 1 (IMP1) that is hypothesized to play a role in eliciting protective immunity against E. maxima infection in chickens. RT-PCR analysis of RNA from unsporulated and sporulating E. maxima oocysts revealed highest transcription levels at 6-12h of sporulation with a considerable downregulation thereafter. Alignment of IMP1 coding sequence from Houghton, Weybridge, and APU-1 strains of E. maxima revealed single nucleotide polymorphisms that in some instances led to amino acid changes in the encoded protein sequence. The E. maxima (APU-1) IMP1 cDNA sequence was cloned and expressed in 2 different polyHis Escherichia coli expression vectors. Regardless of expression vector, recombinant E. maxima IMP1 (rEmaxIMP1) was fairly unstable in non-denaturing buffer, which is consistent with stability analysis of the primary amino acid sequence. Antisera specific for rEmaxIMP1 identified a single 72 kDa protein or a 61 kDa protein by non-reducing or reducing SDS-PAGE/immunoblotting. Immunofluorescence staining with anti-rEmaxIMP1, revealed intense surface staining of E. maxima sporozoites, with negligible staining of merozoite stages. Immuno-histochemical staining of E. maxima-infected chicken intestinal tissue revealed staining of E. maxima developmental stages in the lamnia propia and crypts at both 24 and 48 h post-infection, and negligible staining thereafter. The expression of IMP1 during early stages of in vivo development and its location on the sporozoite surface may explain in part the immunoprotective effect of this protein against E. maxima infection.

  14. A surface enhanced Raman scattering spectroscopic study of UO{sub 2}{sup 2+} at trace concentration

    Energy Technology Data Exchange (ETDEWEB)

    Franzen, Carola [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Surface Processes; Carstensen, Lale [Technische Univ. Dresden (Germany); Firkala, T. [Helmholtz Institute Freiberg for Resource Technology, Freiberg (Germany); Steudtner, Robin [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Inst. of Resource Ecology

    2017-06-01

    Techniques for rapid screening of uranium in environmental samples are needed. This study entails the development of Surface-Enhanced Raman scattering (SERS) spectroscopy for analyzing uranium(VI) in aqueous media with improved sensitivity.

  15. Spectroscopic measurements of the surface waters for evaluating the fresh-water transport to marine environments in the Southern Baltic

    Science.gov (United States)

    Drozdowska, Violetta; Markuszewski, Piotr; Kowalczyk, Jakub; Makuch, Przemysław; Pakszyc, Paulina; Strzałkowska, Agata; Piskozub, Jacek; Petelski, Tomasz; Zieliński, Tymon; Gutowska, Dorota

    2014-05-01

    To asses concentration and spatial distribution of surface-active molecules (surfactants) the spectrophotometric and spectrofluorometric measurements of water samples taken from a surface film and a depth 0.5 m were carried out during three cruises of r/v Oceania in Springs' 2010-2011 and Autumn' 2012. Measurements were conducted along the transects from the river outlets to the open waters of the Southern Baltic Sea. Surfactants consist of polar molecules of marine dissolved organic matter and are chemically not entirely classified. However, fractions of dissolved organic matter having chromophores or fluorophores (CDOM or FDOM) are recognized through their specific absorption and fluorescence spectra. The sea surface is a layer of transition between the atmosphere and the sea, where there is a variety of biological, physical and chemical processes which contribute to the accumulation and exchange of surfactants, the chemical species concentrated in the surface layer (surface active agents). The main source of marine surfactants are remains of phytoplankton and its degradation products, created by bacterial activity, and as a result of condensation of molecules of low molecular weight to form of surface-active macromolecules. The presence of surfactants in the surface layers can significantly affect the access of solar energy into the sea as well as the air-sea interaction processes. The main objective of the research was to investigate the luminescent properties of surfactants, sampled in different regions of the Southern Baltic, and to find the differences between a surface film and a subsurface layer (of 50 cm). The next aim was to combine the differences in optical properties with the different dynamics for various river outlets. The results of spectrophotometric studies show the differences in the intensity of spectral bands, particularly between coastal (estuaries) and the open sea zones. Also, analysis of the spectra shows differences between areas of the

  16. Spectroscopic and Kinetic Characterization of Peroxidase-Like π-Cation Radical Pinch-Porphyrin-Iron(III Reaction Intermediate Models of Peroxidase Enzymes

    Directory of Open Access Journals (Sweden)

    Samuel Hernández Anzaldo

    2016-06-01

    Full Text Available The spectroscopic and kinetic characterization of two intermediates from the H2O2 oxidation of three dimethyl ester [(proto, (meso, (deuteroporphyrinato (picdien]Fe(III complexes ([FePPPic], [FeMPPic] and [FeDPPic], respectively pinch-porphyrin peroxidase enzyme models, with s = 5/2 and 3/2 Fe(III quantum mixed spin (qms ground states is described herein. The kinetic study by UV/Vis at λmax = 465 nm showed two different types of kinetics during the oxidation process in the guaiacol test for peroxidases (1–3 + guaiacol + H2O2 → oxidation guaiacol products. The first intermediate was observed during the first 24 s of the reaction. When the reaction conditions were changed to higher concentration of pinch-porphyrins and hydrogen peroxide only one type of kinetics was observed. Next, the reaction was performed only between pinch-porphyrins-Fe(III and H2O2, resulting in only two types of kinetics that were developed during the first 0–4 s. After this time a self-oxidation process was observed. Our hypotheses state that the formation of the π-cation radicals, reaction intermediates of the pinch-porphyrin-Fe(III family with the ligand picdien [N,N’-bis-pyridin-2-ylmethyl-propane-1,3-diamine], occurred with unique kinetics that are different from the overall process and was involved in the oxidation pathway. UV-Vis, 1H-NMR and ESR spectra confirmed the formation of such intermediates. The results in this paper highlight the link between different spectroscopic techniques that positively depict the kinetic traits of artificial compounds with enzyme-like activity.

  17. Surface characterization and direct bioelectrocatalysis of multicopper oxidases

    Energy Technology Data Exchange (ETDEWEB)

    Ivnitski, Dmitri M., E-mail: ivnitski@unm.ed [Chemical and Nuclear Engineering, University of New Mexico, Albuquerque 87131 (United States)] [Air Force Research Laboratory, AFRL/RXQL, Microbiology and Applied Biochemistry, Tyndall Air Force Base, FL 32403 (United States); Khripin, Constantine [Chemical and Nuclear Engineering, University of New Mexico, Albuquerque 87131 (United States); Luckarift, Heather R. [Air Force Research Laboratory, AFRL/RXQL, Microbiology and Applied Biochemistry, Tyndall Air Force Base, FL 32403 (United States)] [Universal Technology Corporation, 1270 N. Fairfield Road, Dayton, OH 45432 (United States); Johnson, Glenn R. [Air Force Research Laboratory, AFRL/RXQL, Microbiology and Applied Biochemistry, Tyndall Air Force Base, FL 32403 (United States); Atanassov, Plamen, E-mail: plamen@unm.ed [Chemical and Nuclear Engineering, University of New Mexico, Albuquerque 87131 (United States)

    2010-10-01

    Multicopper oxidases (MCO) have been extensively studied as oxygen reduction catalysts for cathodic reactions in biofuel cells. Theoretically, direct electron transfer between an enzyme and electrode offers optimal energy conversion efficiency providing that the enzyme/electrode interface can be engineered to establish efficient electrical communication. In this study, the direct bioelectrocatalysis of three MCO (Laccase from Trametes versicolor, bilirubin oxidase (BOD) from the fungi Myrothecium verrucaria and ascorbate oxidase (AOx) from Cucurbita sp.) was investigated and compared as oxygen reduction catalysts. Protein film voltammetry and electrochemical characterization of the MCO electrodes showed that DET had been successfully established in all cases. Atomic force microscopy imaging and force measurements indicated that enzyme was immobilized as a monolayer on the electrode surface. Evidence for three clearly separated anodic and cathodic redox events related to the Type 1 (T1) and the trinculear copper centers (T2, T3) of various MCO was observed. The redox potential of the T1 center was strongly modulated by physiological factors including pH, anaerobic and aerobic conditions and the presence of inhibitors.

  18. Spectroscopic studies of surface-gas interactions and catalyst restructuring at ambient pressure: mind the gap{exclamation_point}

    Energy Technology Data Exchange (ETDEWEB)

    Rupprechter, Guenther; Weilach, Christian [Institute of Materials Chemistry, Vienna University of Technology, Veterinaerplatz 1, A-1210 Vienna (Austria)], E-mail: grupp@imc.tuwien.ac.at

    2008-05-07

    Recent progress in the application of surface vibrational spectroscopy at ambient pressure allows us to monitor surface-gas interactions and heterogeneous catalytic reactions under conditions approaching those of technical catalysis. The surface specificity of photon-based methods such as polarization modulation infrared reflection absorption spectroscopy (PM-IRAS) and sum frequency generation (SFG) spectroscopy is utilized to monitor catalytically active surfaces while they function at high pressure and high temperature. Together with complementary information from high-pressure x-ray photoelectron spectroscopy (HP-XPS) and high-resolution transmission electron microscopy (HRTEM), reaction mechanisms can be deduced on a molecular level. Well defined model catalysts, prepared under ultrahigh vacuum (UHV), are typically employed in such studies, including smooth and stepped single crystals, thin oxide films, and oxide-supported nanoparticles. A number of studies on unsupported and supported noble metal (Pd, Rh) catalysts are presented, focusing on the transformation of the catalysts from the 'as-prepared' to the 'active state'. This often involves pronounced alterations in catalyst structure and composition, for example the creation of surface carbon phases, surface oxides or surface alloys, as well as nanoparticle restructuring. The reactivity studies include CH{sub 3}OH, CH{sub 4} and CO oxidation with gas phase analysis by gas chromatography and mass spectrometry. Differing results between studies under ultrahigh vacuum and ambient pressure, and between studies on single crystals and supported nanoparticles, demonstrate the importance of 'minding the gap' between idealized and realistic conditions.

  19. CHARACTERIZATION OF A SAMPLE OF INTERMEDIATE-TYPE AGNs. I. SPECTROSCOPIC PROPERTIES AND SERENDIPITOUS DISCOVERY OF NEW DUAL AGNs

    Energy Technology Data Exchange (ETDEWEB)

    Benitez, Erika; Cruz-Gonzalez, Irene; Martinez, Benoni; Jimenez-Bailon, Elena [Instituto de Astronomia, Universidad Nacional Autonoma de Mexico, Apdo. Postal 70-264, Mexico D.F. 04510 (Mexico); Mendez-Abreu, Jairo; Lopez-Martin, Luis [Instituto de Astrofisica de Canarias, E-38200 La Laguna, Tenerife (Spain); Fuentes-Carrera, Isaura [Escuela Superior de Fisica y Matematicas, Instituto Politecnico Nacional (ESFM-IPN), U.P. Adolfo Lopez Mateos, Mexico D.F. 07730 (Mexico); Leon-Tavares, Jonathan [Aalto University Metsaehovi Radio Observatory, Metsaehovintie 114, FI-02540, Kylmaelae (Finland); Chavushyan, Vahram H., E-mail: erika@astro.unam.mx [Instituto Nacional de Astrofisica, Optica y Electronica, Apdo. Postal 51-216, 72000 Puebla (Mexico)

    2013-01-20

    A sample of 10 nearby intermediate-type active galactic nuclei (AGNs) drawn from the Sloan Digital Sky Survey is presented. The aim of this work is to provide estimations of the black hole (BH) mass for the sample galaxies from the dynamics of the broad-line region. For this purpose, a detailed spectroscopic analysis of the objects was done. Using Baldwin-Phillips-Terlevich diagnostic diagrams, we have carefully classified the objects as true intermediate-type AGNs and found that 80%{sup +7.2%} {sub -17.3%} are composite AGNs. The BH mass estimated for the sample is within 6.54 {+-} 0.16 < log M {sub BH} < 7.81 {+-} 0.14. Profile analysis shows that five objects (J120655.63+501737.1, J121607.08+504930.0, J141238.14+391836.5, J143031.18+524225.8, and J162952.88+242638.3) have narrow double-peaked emission lines in both the red (H{alpha}, [N II] {lambda}{lambda}6548,6583 and [S II] {lambda}{lambda}6716, 6731) and the blue (H{beta} and [O III] {lambda}{lambda}4959, 5007) regions of the spectra, with velocity differences ({Delta}V) between the double peaks within 114 km s{sup -1} < {Delta}V < 256 km s{sup -1}. Two of them, J121607.08+504930.0 and J141238.14+391836.5, are candidates for dual AGNs since their double-peaked emission lines are dominated by AGN activity. In searches of dual AGNs, type 1, type II, and intermediate-type AGNs should be carefully separated, due to the high serendipitous number of narrow double-peaked sources (50% {+-} 14.4%) found in our sample.

  20. Low-temperature and time-resolved spectroscopic characterization of the LOV2 domain of Avena sativa phototropin 1

    Science.gov (United States)

    Gauden, Magdalena; Crosson, Sean; van Stokkum, I. H. M.; van Grondelle, Rienk; Moffat, Keith; Kennis, John T. M.

    2004-09-01

    The phototropins are plant blue-light receptors that base their light-dependent action on the reversible formation of a covalent bond between a flavin mononucleotide (FMN) cofactor and a conserved cysteine residue in light, oxygen or voltage (LOV) domains. The spectroscopic properties of the LOV2 domain of phototropin 1 of Avena sativa (oat) have been investigated by means of low-temperature absorption and fluorescence spectroscopy and by time-resolved fluorescence spectroscopy. The low-temperature absorption spectrum of the LOV2 domain showed a fine structure around 473 nm, indicating heterogeneity in the flavin binding pocket. The fluorescence quantum yield of the flavin cofactor increased from 0.13 to 0.41 upon cooling the sample from room temperature to 77 K. A pronounced phosphorescence emission around 600 nm was observed in the LOV2 domain between 77 and 120 K, allowing for an accurate positioning of the flavin triplet state in the LOV2 domain at 16900 cm-1. Fluorescence from the cryotrapped covalent adduct state was extremely weak, with a fluorescence spectrum showing a maximum at 440 nm. Time-resolved fluorescence experiments utilizing a synchroscan streak camera revealed a singlet-excited state lifetime of the LOV2 domain of 2.4 ns. FMN dissolved in aqueous solution showed a pH-dependent lifetime ranging between 2.9 ns at pH 2.0 to 4.7 ns at pH 8.0. No spectral shifting of the flavin emission was observed in the LOV2 domain nor in FMN in aqueous solution.

  1. Spectroscopic characterization of enzymatic flax retting: Factor analysis of FT-IR and FT-Raman data

    Science.gov (United States)

    Archibald, D. D.; Henrikssen, G.; Akin, D. E.; Barton, F. E.

    1998-06-01

    Flax retting is a chemical, microbial or enzymatic process which releases the bast fibers from the stem matrix so they can be suitable for mechanical processing before spinning into linen yarn. This study aims to determine the vibrational spectral features and sampling methods which can be used to evaluate the retting process. Flax stems were retted on a small scale using an enzyme mixture known to yield good retted flax. Processed stems were harvested at various time points in the process and the retting was evaluated by conventional methods including weight loss, color difference and Fried's test, a visual ranking of how the stems disintegrate in hot water. Spectroscopic measurements were performed on either whole stems or powders of the fibers that were mechanically extracted from the stems. Selected regions of spectra were baseline and amplitude corrected using a variant of the multiplicative signal correction method. Principal component regression and partial least-squares regression with full cross-validation were used to determine the spectral features and rate of spectral transformation by regressing the spectra against the retting time in hours. FT-Raman of fiber powders and FT-IR reflectance of whole stems were the simplest and most precise methods for monitoring the retting transformation. Raman tracks the retting by measuring the decrease in aromatic signal and subtle changes in the C-H stretching vibrations. The IR method uses complex spectral features in the fingerprint and carbonyl region, many of which are due to polysaccharide components. Both spectral techniques monitor the retting process with greater precision than the reference method.

  2. Characterization of the interaction between human lactoferrin and lomefloxacin at physiological condition: Multi-spectroscopic and modeling description

    Energy Technology Data Exchange (ETDEWEB)

    Chamani, J., E-mail: Chamani@ibb.ut.ac.i [Department of Biology, Faculty of Science, Islamic Azad University-Mashhad Branch, Mashhad (Iran, Islamic Republic of); Tafrishi, N. [Department of Biology, Faculty of Science, Islamic Azad University-Mashhad Branch, Mashhad (Iran, Islamic Republic of); Momen-Heravi, M. [Department of Chemistry, Faculty of Science, Islamic Azad University-Mashhad Branch, Mashhad (Iran, Islamic Republic of)

    2010-07-15

    The interaction between lomefloxacin (LMF) and human lactoferrin (Hlf) was studied by using fluorescence, circular dichroism (CD) spectroscopic and molecular modeling measurements. By the fluorescence quenching results, it was found that the binding constant K{sub A}=8.69x10{sup 5} L mol{sup -1}, and number of binding sites n=1.75 at physiological condition. Experimental results observed showed that the binding of LMF to Hlf induced conformational changes of Hlf. The participation of tyrosyl and tryptophanyl residues of protein was also estimated in the drug-Hlf complex by synchronous fluorescence. The quantitative analysis data of far-UV CD spectra from that of the alpha-helix 37.4% in free Hlf to 30.2% in the LMF-Hlf complex further confirmed that secondary structure of the protein was changed by LMF. Near-UV CD showed perturbations around tryptophan and tyrosine residues which involves perturbations of tertiary structure. The thermodynamic parameters like, DELTAH{sup o} and DELTAS{sup o}, have been calculated to be 63.411 kJ mol{sup -1} and 231.104 J mol{sup -1} K{sup -1}, respectively. Thermodynamic analysis showed that hydrophobic interactions were the main force in the binding site but the hydrogen bonding and electrostatic interaction could not be excluded which in agreement with the result of molecular docking study. The distance r between donor and acceptor was obtained according to fluorescence resonance energy transfer (FRET) and found to be 1.78 nm. The interaction between LMF and Hlf has been verified as consistent with the static quenching procedure and the quenching mechanism is related to the energy transfer. Furthermore, the study of molecular modeling that LMF could bind to the alpha-helixes between Pro145-Asn152 and Phe167-Gln172 regions and hydrophobic interaction was the major acting force for the binding site, which was in agreement with the thermodynamic analysis.

  3. A contribution to the surface characterization of alkali metal sulfates

    Energy Technology Data Exchange (ETDEWEB)

    Fantauzzi, Marzia; Rigoldi, Americo; Elsener, Bernhard; Atzei, Davide; Rossi, Antonella, E-mail: rossi@unica.it

    2014-03-01

    Highlights: • Full electronic characterization of alkali metals sulfates by X-ray photoelectron spectroscopy and X-ray induced Auger electron spectroscopy. • Curve-fitting of SKLL signals makes possible to clarify the role of the cation in the series of alkali metal sulfates. • Differences in the binding energies and Auger parameter are discussed in terms of the electronic properties and the polarizability of the cation. • The line intensities are analyzed and a thorough quantitative analysis is presented. - Abstract: The analytical characterization of surfaces of sulfur-bearing samples that present sulfides, polysulfides and/or elemental sulfur as reaction products can be difficult by simply relying on the binding energy of the S2p X-ray photoelectron signals, due to the small chemical shifts. In such cases the Auger parameter concept can be used to distinguish among different chemical states, but this requires a model to curve fit complex Auger SKLL signals in order to resolve the contributions arising from sulfur in different chemical states on the surface. With this scope a detailed X-ray photoelectron spectroscopy (XPS) and X-ray induced Auger electron spectroscopy (XAES) surface analytical study of the group IA sulfates is presented in this paper. Sulfates were chosen as model compounds for curve fitting the X-ray induced SKLL spectra since in these compounds sulfur is present in a unique chemical state. For the first time the multicomponent SKLL spectra are fitted with model functions consisting of an intense {sup 1}D and a low intensity {sup 1}S contribution with constant energy difference of 8 eV. It was found that the kinetic energy of the SK{sub 2,3}L{sub 2,3} ({sup 1}D) line increases from 2105.1 ± 0.1 to 2107.5 ± 0.2 eV whereas the corresponding S2p{sub 3/2} binding energy decreases from 169.5 ± 0.1 eV for Li{sub 2}SO{sub 4} to 167.8 ± 0.1 eV for Cs{sub 2}SO{sub 4}. Shifts to lower binding energy values are observed also for S2p, S2s and O1

  4. STUDIES ON SURFACE CHARACTERIZATION AND ECOMATERIAL SHEET DEGRADATION OF BASALT FIBERS BY PLASMA TREATMENTS AND WOOD FIBERS

    Institute of Scientific and Technical Information of China (English)

    Guangjian Wang; Yajie Guo; Deku Shang; linna Hu; Zhenhua Guo; Kailiang Zhang

    2004-01-01

    Plasma surface modification (Argon: Hydrogen =0.6:0.4) of basalt fibers was investigated and the element contents of basalt and wood fibers were determined by X-ray energy dispersion spectroscope (EDS).Configuration of basalt fibers was described by means of confocal Laser Raman microRaman spectrometer and Fourier transform infrared spectroscopy. And the morphology of fiber surface was studied with scanning electron microscope(SEM). The modified samples were characterized by X-ray photoelectron spectra (XPS). The results showed that the roughness of basalt fibers was increased with the increase of exposure time of plasma. At the same time the wettability and surface characteristics such as active groups of NH2, OH were improved as well. Basaltfibers were of good chemical stability, better mechanism intension and thermo-stability etc. They mainly consist of [SiO4]4-,[Si2O6]4-, [Si2O5]2-. Further experiments demostrated that they were degraded into edaphic matrix after use.Therefore, they were environmentally friendly.

  5. Synthesis, crystal structure, spectroscopic characterization and nonlinear optical properties of manganese (II) complex of picolinate: A combined experimental and computational study

    Science.gov (United States)

    Tamer, Ömer; Avcı, Davut; Atalay, Yusuf; Çoşut, Bünyemin; Zorlu, Yunus; Erkovan, Mustafa; Yerli, Yusuf

    2016-02-01

    A novel manganese (II) complex with picolinic acid (pyridine 2-carboxylic acid, Hpic), namely, [Mn(pic)2(H2O)2] was prepared and its crystal structure was fully characterized by using single crystal X-ray diffraction. Picolinate (pic) ligands were coordinated to the central manganese(II) ion as bidentate N,O-donors through the nitrogen atoms of pyridine rings and the oxygen atoms of carboxylate groups forming five-membered chelate rings. The spectroscopic characterization of Mn(II) complex was performed by the applications of FT-IR, Raman, UV-vis and EPR techniques. In order to support these studies, density functional theory (DFT) calculations were carried out by using B3LYP level. IR and Raman spectra were simulated at B3LYP level, and obtained results indicated that DFT calculations generally give compatible results to the experimental ones. The electronic structure of the Mn(II) complex was predicted using time dependent DFT (TD-DFT) method with polarizable continuum model (PCM). Molecular stability, hyperconjugative interactions, intramolecular charge transfer (ICT) and bond strength were investigated by applying natural bond orbital (NBO) analysis. Nonlinear optical properties of Mn(II) complex were investigated by the determining of molecular polarizability (α) and hyperpolarizability (β) parameters.

  6. Physicochemical properties of surfaces of SBA-15 silicas, according to adsorption-static, gas-chromatographic, and IR spectroscopic data

    Science.gov (United States)

    Roshchina, T. M.; Shoniya, N. K.; Tegina, O. Ya.; Tkachenko, O. P.; Kustov, L. M.

    2016-01-01

    Interaction between vapors of organic compounds and water with surfaces of mesoporous silica SBA-15 and silica SBA-15 modified with n-C6F13(CH2)2Si(CH3)2Cl via adsorption under static conditions is studied by means of gas chromatography and IR diffuse reflectance spectroscopy. It is shown that modification notably reduces the energy of disperse and specific interactions, along with the acidity of adsorption centers. Even low concentrations of the grafted groups (0.76 nm-2) allows us to obtain highly hydrophobic coatings on SBA-15 surfaces.

  7. 77 FR 5813 - Cardiovascular Metallic Implants: Corrosion, Surface Characterization, and Nickel Leaching...

    Science.gov (United States)

    2012-02-06

    ... HUMAN SERVICES Food and Drug Administration Cardiovascular Metallic Implants: Corrosion, Surface... public workshop entitled ``Cardiovascular Metallic Implants: Corrosion, Surface Characterization, and... implants are made of metals and may be susceptible to corrosion, it is unclear whether the...

  8. Spectroscopic and functional characterization of iron-sulfur cluster-bound forms of Azotobacter vinelandii (Nif)IscA.

    Science.gov (United States)

    Mapolelo, Daphne T; Zhang, Bo; Naik, Sunil G; Huynh, Boi Hanh; Johnson, Michael K

    2012-10-16

    The mechanism of [4Fe-4S] cluster assembly on A-type Fe-S cluster assembly proteins, in general, and the specific role of (Nif)IscA in the maturation of nitrogen fixation proteins are currently unknown. To address these questions, in vitro spectroscopic studies (UV-visible absorption/CD, resonance Raman and Mössbauer) have been used to investigate the mechanism of [4Fe-4S] cluster assembly on Azotobacter vinelandii(Nif)IscA, and the ability of (Nif)IscA to accept clusters from NifU and to donate clusters to the apo form of the nitrogenase Fe-protein. The results show that (Nif)IscA can rapidly and reversibly cycle between forms containing one [2Fe-2S](2+) and one [4Fe-4S](2+) cluster per homodimer via DTT-induced two-electron reductive coupling of two [2Fe-2S](2+) clusters and O(2)-induced [4Fe-4S](2+) oxidative cleavage. This unique type of cluster interconversion in response to cellular redox status and oxygen levels is likely to be important for the specific role of A-type proteins in the maturation of [4Fe-4S] cluster-containing proteins under aerobic growth or oxidative stress conditions. Only the [4Fe-4S](2+)-(Nif)IscA was competent for rapid activation of apo-nitrogenase Fe protein under anaerobic conditions. Apo-(Nif)IscA was shown to accept clusters from [4Fe-4S] cluster-bound NifU via rapid intact cluster transfer, indicating a potential role as a cluster carrier for delivery of clusters assembled on NifU. Overall the results support the proposal that A-type proteins can function as carrier proteins for clusters assembled on U-type proteins and suggest that they are likely to supply [2Fe-2S] clusters rather than [4Fe-4S] for the maturation of [4Fe-4S] cluster-containing proteins under aerobic or oxidative stress growth conditions.

  9. Surface mineralization and characterization of tobacco mosaic virus biotemplated nanoparticles

    Science.gov (United States)

    Freer, Alexander S.

    The genetically engineered tobacco mosaic virus (TMV) has been utilized as a biotemplate in the formation of nanoparticles with the intent of furthering the understanding of the biotemplated nanoparticles formed in the absence of an external reducing agent. Specifically, the work aims to provide better knowledge of the final particle characteristics and how these properties could be altered to better fit the need of functional devices. Three achievements have been accomplished including a method for controlling final particle size, characterizing the resistivity of palladium coated TMV, and the application of TMV as an additive in nanometric calcium carbonate synthesis. Until the last 5 years, formation of metal nanoparticles on the surface of TMV has always occurred with the addition of an external reducing agent. The surface functionalities of genetically engineered TMV allow for the reduction of palladium in the absence of an external reducing agent. This process has been furthered to understand how palladium concentration affects the final coating uniformity and thickness. By confirming an ideal ratio of palladium and TMV concentrations, a uniform coat of palladium is formed around the viral nanorod. Altering the number of palladium coating cycles at these concentrations allows for a controllable average diameter of the final nanorods. The average particle diameter was determined by small angle x-ray scattering (SAXS) analysis by comparing the experimental results to the model of scattering by an infinitely long cylinder. The SAXS results were confirmed through transmission electron microscopy images of individual Pd-TMV nanorods. Secondly, methodologies to determine the electrical resistivity of the genetically engineered TMV biotemplated palladium nanoparticles were created to provide valuable previously missing information. Two fairly common nanoelectronic characterization techniques were combined to create the novel approach to obtain the desired

  10. Spectroscopic data

    CERN Document Server

    Melzer, J

    1976-01-01

    During the preparation of this compilation, many people contributed; the compilers wish to thank all of them. In particular they appreciate the efforts of V. Gilbertson, the manuscript typist, and those of K. C. Bregand, J. A. Kiley, and W. H. McPherson, who gave editorial assistance. They would like to thank Dr. J. R. Schwartz for his cooperation and encouragement. In addition, they extend their grati­ tude to Dr. L. Wilson of the Air Force Weapons Laboratory, who gave the initial impetus to this project. v Contents I. I ntroduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 . . . . . . . . . . . . . . . . 11. Organization ofthe Spectroscopic Table. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Methods of Production and Experimental Technique . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Band Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2...

  11. Macroscopic and spectroscopic characterization of selenate, selenite, and chromate adsorption at the solid-water interface of gamma-Al(2)O(3).

    Science.gov (United States)

    Elzinga, Evert J; Tang, Yuanzhi; McDonald, Jason; DeSisto, Stephanie; Reeder, Richard J

    2009-12-15

    The interaction of selenate, selenite, and chromate with the hydrated surface of gamma-Al(2)O(3) was studied using a combination of macroscopic pH edge data, electrophoretic mobility measurements, and X-ray absorption spectroscopic analyses. The pH edge data show generally increased oxyanion adsorption with decreasing pH, and indicate ionic strength-(in)dependent adsorption of chromate and selenate across the pH range 4-9, and ionic strength-(in)dependent adsorption of selenite in this pH range. The adsorption of chromate peaks at pH 5.0, whereas for selenate and selenite no pH adsorption maxima are observed. Electrophoretic mobility measurements show that all three oxyanions decrease the zeta potential of gamma-Al(2)O(3) upon adsorption; however, only selenite decreased the pH(PZC) of the gamma-Al(2)O(3) sorbent. EXAFS data indicate that selenite ions are coordinated in a bridging bidentate fashion to surface AlO(6) octahedra, whereas no second-neighbor Al scattering was observed for adsorbed selenate ions. Combined, the results presented here show that pH is a major factor in determining the extent of adsorption of selenate, selenite, and chromate on hydrated gamma-Al(2)O(3). The results point to substantial differences between these anions as to the mode of adsorption at the hydrated gamma-Al(2)O(3) surface, with selenate adsorbing as nonprotonated outer-sphere complexes, chromate forming a mixture of monoprotonated and nonprotonated outer-sphere adsorption complexes, and selenite coordinating as inner-sphere surface complexes in bridging configuration.

  12. Immobilization of oligonucleotide probes on silicon surfaces using biotin–streptavidin system examined with microscopic and spectroscopic techniques

    Energy Technology Data Exchange (ETDEWEB)

    Awsiuk, K., E-mail: kamil.awsiuk@uj.edu.pl [M. Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, Kraków 30-059 (Poland); Rysz, J. [M. Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, Kraków 30-059 (Poland); Petrou, P. [Institute of Nuclear and Radiological Sciences and Technology, Energy and Safety, NCSR “Demokritos”, End Patriarchou Gregoriou Str., Aghia Paraskevi 15310 (Greece); Budkowski, A. [M. Smoluchowski Institute of Physics, Jagiellonian University, Reymonta 4, Kraków 30-059 (Poland); Bernasik, A. [Faculty of Physics and Applied Computer Science, AGH-University of Science and Technology, Al. Mickiewicza 30, Kraków 30-059 (Poland); Kakabakos, S. [Institute of Nuclear and Radiological Sciences and Technology, Energy and Safety, NCSR “Demokritos”, End Patriarchou Gregoriou Str., Aghia Paraskevi 15310 (Greece); Marzec, M.M. [Faculty of Physics and Applied Computer Science, AGH-University of Science and Technology, Al. Mickiewicza 30, Kraków 30-059 (Poland); Raptis, I. [Institute for Advanced Materials, Physicochemical Processes, Nanotechnology and Microsystems, NCSR “Demokritos”, End Patriarchou Gregoriou Str., Aghia Paraskevi 15310 (Greece)

    2014-01-30

    To immobilize effectively oligonucleotide probes on SiO{sub 2} modified with (3-aminopropyl)triethoxysilane, four procedures based on streptavidin–biotin system are compared with Atomic Force Microscopy, Angle-Resolved X-ray Photoelectron Spectroscopy and Time-of-Flight Secondary Ion Mass Spectrometry. The first approach involves: adsorption of biotinylated Bovine Serum Albumin, blocking free surface sites with BSA, binding of streptavidin and biotinylated oligonucleotide (b-oligo). Final steps are exchanged in the second procedure with immobilization of preformed streptavidin–b-oligo conjugate. The third approach consists of streptavidin adsorption, blocking with BSA and b-oligo binding. Finally, streptavidin–b-oligo conjugate is immobilized directly within the fourth method. Surface coverage with biomolecules, determined from ARXPS, accords with average AFM height, and is anti-correlated with the intensity of Si+ ions. Higher biomolecular coverage was achieved during the last steps of the first (2.45(±0.38) mg/m{sup 2}) and second (1.31(±0.22) mg/m{sup 2}) approach, as compared to lower surface density resulting from the third (0.58(±0.20) mg/m{sup 2}) and fourth (0.41(±0.11) mg/m{sup 2}) method. Phosphorus atomic concentration indicates effectiveness of oligonucleotide immobilization. Secondary ions intensities, characteristic for oligonucleotides, streptavidin, BSA, and proteins, allow additional insight into overlayer composition. These measurements verify the ARXPS results and show the superiority of the first two immobilization approaches in terms of streptavidin and oligonucleotide density achieved onto the surface.

  13. Spectroscopic characterization and energy transfer process in cobalt and cobalt-iron co-doped ZnSe/ZnS crystals

    Science.gov (United States)

    Peppers, J.; Martyshkin, D. V.; Fedorov, V. V.; Mirov, S. B.

    2014-02-01

    Cobalt doped II-VI wide band semiconductors (e.g. ZnSe, ZnS, CdSe) are promising media for infrared (IR) laser applications. They could be utilized as effective passive Q-switches for cavities of Alexandrite as well as Nd and Er lasers operating over 0.7-0.8, 1.3-1.6, and ~2.8 μm spectral ranges. We report spectroscopic characterization of Co:ZnSe and Co:ZnS crystals. Absorption cross-sections were measured for 4A2(F) → 4T1(P), 4A2(F) → 4T1(F), and 4A2(F) → 4T2(F) transitions with maximum absorption at 768(726), 1615(1500), 2690(2740) nm for ZnSe(ZnS) crystals, respectively. The calculated absorption cross-sections of the above transitions were estimated to be 64(56)×1019, 7.5(7.8)×1019, and 0.52(0.49)×1019 cm2 for ZnSe(ZnS) crystal hosts. In addition to the above applications the cobalt ions could be utilized for excitation of Fe2+ ions via resonance energy transfer process. Tunable room temperature lasing of Fe 2+ doped binary and ternary chalcogenides has been successfully demonstrated over 3.5-6 μm spectral range. However, II-VI lasers based on Fe2+ active ions don't feature convenient commercially available pump sources (e.g. some Fe doped crystal hosts require pump wavelengths longer than 3 μm). Therefore, the process of energy transfer from Co2+ to Fe2+ ions could enable utilization of commercially available visible and near-infrared pump sources. We report a spectroscopic characterization of iron-cobalt co-doped ZnS and ZnSe crystals over 14-300K temperature range. Mid-IR laser oscillation at 3.9 μm(3.6 μm) via energy transfer in the Co:Fe:ZnSe (Co:Fe:ZnS) co-doped crystals was demonstrated under cobalt excitation at 4A2(F) → 4T1(P) (~0.7μm) and 4A2(F) → 4T1(F) (~1.56 μm) transitions.

  14. Single-Cell Imaging and Spectroscopic Analyses of Cr(VI) Reduction on the Surface of Bacterial Cells

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yuanmin; Sevinc, Papatya C.; Belchik, Sara M.; Fredrickson, Jim K.; Shi, Liang; Lu, H. Peter

    2013-01-22

    We investigate single-cell reduction of toxic Cr(VI) by the dissimilatory metal-reducing bacterium Shewanella oneidensis MR-1 (MR-1), an important bioremediation process, using Raman spectroscopy and scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDX). Our experiments indicate that the toxic and highly soluble Cr(VI) can be efficiently reduced to the less toxic and non-soluble Cr2O3 nanoparticles by MR-1. Cr2O3 is observed to emerge as nanoparticles adsorbed on the cell surface and its chemical nature is identified by EDX imaging and Raman spectroscopy. Co-localization of Cr2O3 and cytochromes by EDX imaging and Raman spectroscopy suggests a terminal reductase role for MR-1 surface-exposed cytochromes MtrC and OmcA. Our experiments revealed that the cooperation of surface proteins OmcA and MtrC makes the reduction reaction most efficient, and the sequence of the reducing reactivity of the MR-1 is: wild type > single mutant @mtrC or mutant @omcA > double mutant (@omcA-@mtrC). Moreover, our results also suggest that the direct microbial Cr(VI) reduction and Fe(II) (hematite)-mediated Cr(VI) reduction mechanisms may co-exist in the reduction processes.

  15. A surface-enhanced infrared absorption spectroscopic study of pH dependent water adsorption on Au

    Science.gov (United States)

    Dunwell, Marco; Yan, Yushan; Xu, Bingjun

    2016-08-01

    The potential dependent behavior of near-surface water on Au film electrodes in acidic and alkaline solutions is studied using a combination of attenuated total reflectance surface enhanced infrared spectroscopy and chronoamperometry. In acid, sharp νOH peaks appear at 3583 cm- 1 at high potentials attributed to non-H-bonded water coadsorbed in the hydration sphere of perchlorate near the electrode surface. Adsorbed hydronium bending mode at near 1680 cm- 1 is observed at low potentials in low pH solutions (1.4, 4.0, 6.8). At high pH (10.0, 12.3), a potential-dependent OH stretching band assigned to adsorbed hydroxide emerges from 3400-3506 cm- 1. The observation of adsorbed hydroxide, even on a weakly oxophilic metal such as Au, provides the framework for further studies of hydroxide adsorption on other electrodes to determine the role of adsorbed hydroxide on important reactions such as the hydrogen oxidation reaction.

  16. Synthesis and spectroscopic characterization of pyrrole-2,3-diones and their following reactions with 1,2-aromatic diamines

    Directory of Open Access Journals (Sweden)

    İrfan Koca

    2012-01-01

    Full Text Available 4-aroyl-5-aryl-2,3-furandiones and N,N-dialkyl urea combine with loss of water yielding the pyrrole-2,3-dione derivatives in moderate yields (47-68%. Then, these compounds were converted into 2(1H-quinoxalinones with various 1,2-phenylenediamines. The structures and characterizations of the synthesized compounds were established by the 1H- and 13C-NMR, IR and elemental analysis.

  17. Characterization of Sea Lettuce Surface Functional Groups by Potentiometric Titrations

    Science.gov (United States)

    Ebling, A. M.; Schijf, J.

    2008-12-01

    In pursuit of our ultimate goal to better understand the prodigious capacity of the marine macroalga Ulva lactuca (sea lettuce) for adsorbing a broad range of dissolved trace metals from seawater, we performed an initial characterization of its surface functional groups. Specifically, the number of distinct functional groups as well as their individual bulk concentrations and acid dissociation constants (pKas) were determined by potentiometric titrations in NaCl solutions of various ionic strengths (I = 0.01-5.0 M), under inert nitrogen atmosphere at 25°C. Depending on the ionic strength, Ulva samples were manually titrated down to pH 2 or 3 with 1 N HCl and then up to pH 10 with 1 N NaOH in steps of 0.1-0.2 units, continuously monitoring pH with a glass combination electrode. Titrations of a dehydrated Ulva standard reference material (BCR-279) were compared with fresh Ulva tissue cultured in our laboratory. A titration in filtered natural seawater was also compared with one in an NaCl solution of equal ionic strength. Equilibrium constants for the ionization of water in NaCl solutions as a function of ionic strength were obtained from the literature. Fits to the titration data ([H]T vs. pH) were performed with the FITEQL4.0 computer code using non-electrostatic 3-, 4-, and 5-site models, either by fixing ionic strength at its experimental value or by allowing it to be extrapolated to zero, while considering all functional group pKas and bulk concentrations as adjustable parameters. Since pKas and bulk concentrations were found to be strongly correlated, the latter were also fixed in some cases to further constrain the pKas. Whereas these calculations are currently ongoing, preliminary results point to three, possibly four, functional groups with pKas of about 4.1, 6.3, and 9.5 at I = 0. Bulk concentrations of the three groups are very similar, about 5-6×10-4 mol/g based on dry weight, which suggests that all are homogeneously distributed over the surface and

  18. Microscopic and Spectroscopic Characterization of Calcified Microorganisms at the Nanometer-Scale in Experimental and Field Samples.

    Science.gov (United States)

    Benzerara, K.; Yoon, T.; Menguy, N.; Tyliszczak, T.; Brown, G. E.

    2004-12-01

    Calcium phosphates and calcium carbonates are the most prevalent minerals involved in microbial fossilization. Structural characterization of both the organic and mineral components in such samples is, however, usually difficult at the appropriate spatial resolution, i.e., at the submicrometer scale. We have used a combination of Scanning Transmission X-ray microscopy (STXM), a synchrotron-based technique, and High-Resolution Transmission Electron Microscopy (HRTEM) to characterize both the Ca-containing biominerals and the functional groups present in the organic components associated with them (STXM). These data, in turn, provide a better understanding of the mechanisms, products, and biomolecules involved in microbial calcification. We have studied the experimental biomineralization of the model strain Caulobacter crescentus by calcium phosphates, and the calcification of natural biofilms by aragonite in an alkaline lake in Turkey. The precipitation of calcium phosphate and calcium carbonate by microorganisms likely involves different mechanisms. The resulting biominerals were found to have unique features with dimensions in the nanometer-range, preferential crystallographic orientations or unusual morphologies, which provide potential biosignatures. By using C K-edge NEXAFS spectroscopy at a submicrometer scale, we were also able to document the evolution of the organic molecules during the fossilization process and to characterize those involved as templates in the formation of calcium phosphate and carbonate minerals.

  19. Atomic scale characterization and surface chemistry of metal modified titanate nanotubes and nanowires

    Science.gov (United States)

    Kukovecz, Ákos; Kordás, Krisztián; Kiss, János; Kónya, Zoltán

    2016-10-01

    Titanates are salts of polytitanic acid that can be synthesized as nanostructures in a great variety concerning crystallinity, morphology, size, metal content and surface chemistry. Titanate nanotubes (open-ended hollow cylinders measuring up to 200 nm in length and 15 nm in outer diameter) and nanowires (solid, elongated rectangular blocks with length up to 1500 nm and 30-60 nm diameter) are the most widespread representatives of the titanate nanomaterial family. This review covers the properties and applications of these two materials from the surface science point of view. Dielectric, vibrational, electron and X-ray spectroscopic results are comprehensively discussed first, then surface modification methods including covalent functionalization, ion exchange and metal loading are covered. The versatile surface chemistry of one-dimensional titanates renders them excellent candidates for heterogeneous catalytic, photocatalytic, photovoltaic and energy storage applications, therefore, these fields are also reviewed.

  20. Characterization of Pectin Nanocoatings at Polystyrene and Titanium Surfaces

    DEFF Research Database (Denmark)

    Gurzawska, Katarzyna; Dirscherl, Kai; Yihua, Yu

    2013-01-01

    wettability, without any major effect on surface roughness (Sa, Sdr). Furthermore, we demonstrated that it is possible to visualize the pectin RG-Is molecules and even the nanocoatings on titanium surfaces, which have not been presented before. The comparison between polystyrene and titanium surface showed...

  1. Experimental characterization of micromilled surfaces by large range AFM

    DEFF Research Database (Denmark)

    Bariani, Paolo; Bissacco, Giuliano; Hansen, Hans Nørgaard

    2004-01-01

    Surface generation by ball nose micromilling can be simulated based on technological parameters (ball nose radius, axial and radial depth of cut, feed rate, cutting speed). However, surface 3D topography of such surfaces often widely differs from the simulated one due to the distinctive behaviour...

  2. Spectroscopic characterization of the coordination chemistry and hydrolysis of gallium(III) in the presence of aquatic organic matter

    Science.gov (United States)

    Hagvall, Kristoffer; Persson, Per; Karlsson, Torbjörn

    2014-12-01

    Interactions between metals and natural organic matter (NOM) are of great environmental importance and one of the key factors influencing hydrolysis, solubility, and speciation of the metals. However, studying geochemically relevant metals like Al, Fe, and Cu is sometimes associated with analytical problems; for example Fe and Cu are both redox active. Gallium (Ga) is a non-redox active metal that usually occurs at very low concentrations in environmental samples and therefore a wide concentration range of metal(III)-NOM species can be explored by adding Ga(III) to such samples. This makes Ga(III) a good probe and analogue for other metal ions, in particular Al. In addition, due to the increased usage of Ga in society, a better understanding of how Ga interacts with NOM is of importance but such studies are scarce. In this work, Ga(III) interactions with two different organic materials (Suwannee River natural organic matter and Suwannee River fulvic acid) were studied using infrared (IR) and extended X-ray absorption fine structure (EXAFS) spectroscopy in a large experimental range (101-84,076 μg Ga g-1 dry weight; pH 3-8). Our IR spectroscopic results showed that Ga(III) is bonded mainly to carboxylic functional groups and suggested that only a fraction of the total number of carboxylic sites in the samples was actively involved in the bonding. Modeling of the EXAFS data revealed that Ga(III) formed mononuclear chelate complexes with NOM that strongly suppressed the hydrolysis and polymerization of Ga(III). At low Ga(III) concentrations (1675-16,649 μg g-1) organic complexes, consisting of 1-3 chelate ring structures, were the dominating species in the entire pH range while at higher concentrations (67,673-84,076 μg g-1, pH 3.0-7.0) we detected mixtures of mononuclear organic Ga(III) complexes, Ga(III) (hydr)oxide, and free Ga(III) (here defined as the hydrated Ga(III) ion and its soluble hydrolysis products). Moreover, the EXAFS results showed significantly

  3. Modeling the acid-base properties of bacterial surfaces: A combined spectroscopic and potentiometric study of the gram-positive bacterium Bacillus subtilis.

    Science.gov (United States)

    Leone, Laura; Ferri, Diego; Manfredi, Carla; Persson, Per; Shchukarev, Andrei; Sjöberg, Staffan; Loring, John

    2007-09-15

    In this study, macroscopic and spectroscopic data were combined to develop a surface complexation model that describes the acid-base properties of Bacillus subtilis. The bacteria were freeze-dried and then resuspended in 0.1 M NaCl ionic medium. Macroscopic measurements included potentiometric acid-base titrations and electrophoretic mobility measurements. In addition, ATR-FTIR spectra of wet pastes from suspensions of Bacillus subtilis at different pH values were collected. The least-squares program MAGPIE was used to generate a surface complexation model that takes into account the presence of three acid-base sites on the surface: tripple bond COOH, tripple bond NH+, and tripple bond PO-, which were identified previously by XPS measurements. Both potentiometric titration data and ATR-FTIR spectra were used quantitatively, and electrostatic effects at the charged bacterial surface were accounted for using the constant capacitance model. The model was calculated using two different approaches: in the first one XPS data were used to constrain the ratio of the total concentrations of all three surface sites. The capacitance of the double layer, the total buffer capacity, and the deprotonation constants of the tripple bond NH+, tripple bond POH, and tripple bond COOH species were determined in the fit. A second approach is presented in which the ratio determined by XPS of the total concentrations of tripple bond NH+ to tripple bond PO- sites is relaxed. The total concentration of tripple bond PO- sites was determined in the fit, while the deprotonation constant for tripple bond POH was manually varied until the minimization led to a model which predicted an isoelectric point that resulted in consistency with electrophoretic mobility data. The model explains well the buffering capacity of Bacillus subtilis suspensions in a wide pH range (between pH=3 and pH=9) which is of considerable environmental interest. In particular, a similar quantitative use of the IR data

  4. Characterization of neutrophil adhesion to different titanium surfaces

    Indian Academy of Sciences (India)

    V Campos; R C N Melo; L P Silva; E N Aquino; M S Castro; W Fontes

    2014-02-01

    Although titanium (Ti) is known to elicit a foreign body response when implanted into humans, Ti implant healing resembles normal wound healing in terms of inflammatory cell recruitment and inflammation persistence. Rough implant surfaces may present better conditions for protein adsorption and for the adhesion of platelets and inflammatory cells such as neutrophils. Implanted biomedical devices initially interact with coagulating blood; however, direct contact between the oxide layer of the implant and neutrophils has not been completely described. The aim of the present study is to compare the behaviours of neutrophils in direct contact with different Ti surfaces. Isolated human neutrophils were placed into contact with Ti discs, which had been rendered as `smooth' or `rough', following different surface treatments. Scanning electron microscopy and flow cytometry were used to measure cell adhesion to the surfaces and exposure of membrane proteins such as CD62L and CD11b. Topographic roughness was demonstrated as higher for SLA treated surfaces, measured by atomic force microscopy and elemental analysis was performed by energy dispersive X-ray, showing a similar composition for both surfaces. The adhesion of neutrophils to the `rough' Ti surface was initially stronger than adhesion to the `smooth' surface. The cell morphology and adhesion marker results revealed clear signs of neutrophil activation by either surface, with different neutrophil morphological characteristics being observed between the two surface types. Understanding the cellular mechanisms regulating cell–implant interactions should help researchers to improve the surface topography of biomedical implant devices.

  5. X-ray, Hirshfeld surface analysis, spectroscopic and DFT studies of polycyclic aromatic hydrocarbons: Fluoranthene and acenaphthene

    Directory of Open Access Journals (Sweden)

    Śmiszek-Lindert Wioleta

    2015-01-01

    Full Text Available The X-ray structure, theoretical calculation, Hirshfeld surfaces analysis, IR and Raman spectra of fluoranthene and acenaphthene were reported. Acenaphthene crystallizes in the orthorhombic crystal system and space group P21ma, with crystal parameters a = 7.2053 (9 Å, b = 13.9800 (15 Å, c = 8.2638 (8 Å, Z = 4 and V = 832.41 (16 Å3. In turn, the grown crystals of fluoranthene are in monoclinic system with space group P21/n. The unit cell parameters are a = 18.3490 (2 Å, b = 6.2273 (5 Å, c = 19.8610 (2 Å, β = 109.787 (13°, Z = 8 and unit cell volume is 2135.50 (4 Å3. Theoretical calculations of the title compounds isolated molecule have been carried out using DFT at the B3LYP level. The intermolecular interactions in the crystal structure, for both the title PAHs, were analyzed using Hirshfeld surfaces computational method.

  6. Density, viscosity, surface tension, and spectroscopic properties for binary system of 1,2-ethanediamine + diethylene glycol

    Energy Technology Data Exchange (ETDEWEB)

    Li, Lihua; Zhang, Jianbin, E-mail: tadzhang@pku.edu.cn; Li, Qiang; Guo, Bo; Zhao, Tianxiang; Sha, Feng

    2014-08-20

    Graphical abstract: Excess property of the binary system 1,2-ethanediamine (EDA) + diethylene glycol (DEG). - Highlights: • Densities and viscosities of EDA + DEG at 298.15–318.150 K were listed. • Thermodynamics data of EDA + DEG at 298.15–318.15 K were calculated. • Surface tension of EDA + DEG at 298.15 K was measured. • Intermolecular interaction of EDA with DEG was discussed. - Abstract: This paper reports density and viscosity data at T = 298.15, 303.15, 308.15, 313.15, and 318.15 K and surface tension data at 298.15 K for the binary system 1,2-ethanediamine (EDA) + diethylene glycol (DEG) as a function of composition under atmospheric pressure. From the experimental density and viscosity data, the excess molar volume and viscosity deviation were calculated, and the results were fitted to a Redlich–Kister equation to obtain the coefficients and to estimate the standard deviations between the experimental and calculated quantities. Based on the kinematic viscosity data, enthalpy of activation for viscous flow, entropy of activation for the viscous flow, and Gibbs energies of activation of viscous flow were calculated. In addition, based on Fourier transform infrared spectra, UV–vis spectra, and electrical conductivity for the system EDA + DEG with various concentrations, intermolecular interaction of EDA with DEG was discussed.

  7. Spectroscopic and Structural Studies of a Surface Active Porphyrin in Solution and in Langmuir-Blodgett Films.

    Science.gov (United States)

    Ponce, Concepcion P; Araghi, Hessamaddin Younesi; Joshi, Neeraj K; Steer, Ronald P; Paige, Matthew F

    2015-12-22

    Controlling aggregation of the dual sensitizer-emitter (S-E) zinc tetraphenylporphyrin (ZnTPP) is an important consideration in solid state noncoherent photon upconversion (NCPU) applications. The Langmuir-Blodgett (LB) technique is a facile means of preparing ordered assemblies in thin films to study distance-dependent energy transfer processes in S-E systems and was used in this report to control the aggregation of a functionalized ZnTPP on solid substrates. This was achieved by synthetic addition of a short polar tail to one of the pendant phenyl rings in ZnTPP in order to make it surface active. The surface active ZnTPP derivative formed rigid films at the air-water interface and exhibited mean molecular areas consistent with approximately vertically oriented molecules under appropriate film compression. A red shift in the UV-vis spectra as well as unquenched fluorescence emission of the LB films indicated formation of well-ordered aggregates. However, NCPU, present in the solution phase, was not observed in the LB films, suggesting that NCPU from ZnTPP as a dual S-E required not just a controlled aggregation but a specific orientation of the molecules with respect to each other.

  8. Discovery of starspots on Vega - First spectroscopic detection of surface structures on a normal A-type star

    CERN Document Server

    Böhm, T; Lignières, F; Petit, P; Rainer, M; Paletou, F; Wade, G; Alecian, E; Carfantan, H; Blazère, A; Mirouh, G M

    2014-01-01

    The theoretically studied impact of rapid rotation on stellar evolution needs to be confronted with the results of high resolution spectroscopy-velocimetry observations. A weak surface magnetic field had recently been detected in the A0 prototype star Vega, potentially leading to a (yet undetected) structured surface. The goal of this article is to present a thorough analysis of the line profile variations and associated estimators in the early-type standard star Vega (A0) in order reveal potential activity tracers, exoplanet companions and stellar oscillations. Vega was monitored in high-resolution spectroscopy with the velocimeter Sophie/OHP. A total of 2588 high S/N spectra was obtained during 5 nights (August 2012) at R = 75000 and covering the visible domain. For each reduced spectrum, Least Square Deconvolved (LSD) equivalent photospheric profiles were calculated with a Teff = 9500 and logg = 4.0 spectral line mask. Several methods were applied to study the dynamic behavior of the profile variations (ev...

  9. Raman and surface enhanced Raman spectroscopic studies of specific, small molecule activator of histone acetyltransferase p300

    Science.gov (United States)

    Kundu, Partha P.; Pavan Kumar, G. V.; Mantelingu, Kempegowda; Kundu, Tapas K.; Narayana, Chandrabhas

    2011-07-01

    We report for the first time, the Raman and surface enhanced Raman scattering (SERS) studies of N-(4-chloro-3-trifluoromethyl-phenyl)-2-ethoxy-benzamide (CTB). This molecule is specific activator of human histone acetyltransferase (HAT), p300, and serves as lead molecule to design anti-neoplastic therapeutics. A detailed Raman and SERS band assignments have been performed for CTB, which are compared with the density functional theory calculations. The observed red shift of N sbnd H stretching frequency from the computed wavenumber indicates the weakening of N sbnd H bond resulting from proton transfer to the neighboring oxygen atom. We observe Ag sbnd N vibrational mode at 234 cm -1 in SERS of CTB. This indicates there is a metal-molecule bond leading to chemical enhancement in SERS. We also observe, enhancement in the modes pertaining to substituted benzene rings and methyl groups. Based on SERS analysis we propose the adsorption sites and the orientation of CTB on silver surface.

  10. Control and characterization of textured, hydrophobic ionomer surfaces

    Science.gov (United States)

    Wang, Xueyuan

    Polymer thin films are of increasing interest in many industrial and technological applications. Superhydrophobic, self-cleaning surfaces have attracted a lot of attention for their application in self-cleaning, anti-sticking coatings, stain resistance, or anti-contamination surfaces in diverse technologies, including medical, transportation, textiles, electronics and paints. This thesis focuses on the preparation of nanometer to micrometer-size particle textured surfaces which are desirable for super water repellency. Textured surfaces consisting of nanometer to micrometer-sized lightly sulfonated polystyrene ionomer (SPS) particles were prepared by rapid evaporation of the solvent from a dilute polymer solution cast onto silica. The effect of the solvent used to spin coat the film, the molecular weight of the ionomer, and the rate of solvent evaporation were investigated. The nano-particle or micron-particle textured ionomer surfaces were prepared by either spin coating or solution casting ionomer solutions at controlled evaporation rates. The surface morphologies were consistent with a spinodal decomposition mechanism where the surface first existed as a percolated-like structure and then ripened into droplets if molecular mobility was retained for sufficient time. The SPS particles or particle aggregates were robust and resisted deformation even after annealing at 120°C for one week. The water contact angles on as-prepared surfaces were relatively low, ~ 90° since the polar groups in ionomer reduce the surface hydrophobicity. After chemical vapor deposition of 1H,1H,2H,2H-perfluorooctyltrichlorosilane, the surface contact angles increased to ~ 109° on smooth surfaces and ~140° on the textured surfaces. Water droplets stuck to these surfaces even when tilted 90 degrees. Superhydrophobic surfaces were prepared by spraying coating ionomer solutions and Chemical Vapor Deposition (CVD) of 1H,1H,2H,2H-perfluorooctyltrichlorosilane onto textured surfaces. The

  11. Modern spectroscopic technique in the characterization of biosensitive macrocyclic Schiff base ligand and its complexes: Inhibitory activity against plantpathogenic fungi

    Science.gov (United States)

    Tyagi, Monika; Chandra, Sulekh; Akhtar, Jameel; Chand, Dinesh

    2014-01-01

    Complexes of the type [M(L)Cl2], where M = Co(II), Ni(II) and Cu(II) have been synthesized with a macrocyclic Schiff base ligand (1,4,5,7,10,11,12,15-octaaza,5,11,16,18-tetraphenyl, 3,4,12,13-tetramethyl cyclo-octadecane) derived from Schiff base (obtained by the condensation of 4-aminoantipyrine and dibenzoyl methane) and ethylenediamine. The ligand was characterized on the basis of elemental analysis, IR, 1H NMR, EI Mass and molecular modeling studies while the complexes were characterized by elemental analysis, molar conductance measurements, magnetic susceptibility measurements, IR, electronic and EPR spectral studies. All the complexes are non-electrolyte in nature. The covalency factor (β) and coefficient factor (α) suggest the covalent nature of the complexes. The ligand and its metal complexes have shown antifungal activity with their LD50 values determined by probit analysis against two economically important fungal plant pathogens i.e. Macrophomina phaseolina and Fusarium solani.

  12. Spectroscopic and thermal characterization of alternative model biomembranes from shed skins of Bothrops jararaca and Spilotis pullatus

    Directory of Open Access Journals (Sweden)

    André Rolim Baby

    2009-09-01

    Full Text Available Recently, there has been an interest in the use of shed snake skin as alternative model biomembrane for human stratum corneum. This research work presented as objective the qualitative characterization of alternative model biomembranes from Bothrops jararaca and Spilotis pullatus by FT-Raman, PAS-FTIR and DSC. The employed biophysical techniques permitted the characterization of the biomembranes from shed snake skin of B. jararaca and S. pullatus by the identification of vibrational frequencies and endothermic transitions that are similar to those of the human stratum corneum.Existe atualmente interesse no uso da muda de pele de cobra como modelos alternativos de biomembranas da pele humana. O presente trabalho apresentou como objetivo a caracterização qualitativa de modelos alternativos de biomembranas provenientes de mudas de pele de cobra da Bothrops jararaca e Spilotis pullatus por espectroscopia Raman (FT-Raman, espectroscopia fotoacústica no infravermelho (PAS-FTIR e calorimetria exploratória diferencial (DSC. As técnicas biofísicas FT-Raman, PAS-FTIR e DSC permitiram caracterizar qualitativamente os modelos alternativos de biomembranas provenientes das mudas de pele de cobra da B. jararaca e S. pullatus e identificar freqüências vibracionais e transições endotérmicas similares ao estrato córneo humano.

  13. Optical characterization of HfO{sub 2} by spectroscopic ellipsometry: Dispersion models and direct data inversion

    Energy Technology Data Exchange (ETDEWEB)

    Sancho-Parramon, Jordi [Ruder Boskovic Institute, Bijenicka 54, Zagreb 10000 (Croatia)], E-mail: j.sancho.parramon@gmail.com; Modreanu, Mircea [University College Cork, Tyndall National Institute (TYNDALL), Lee Maltings, Prospect Row, Cork (Ireland); Bosch, Salvador [Universitat de Barcelona, Marti i Franques 1, Barcelona 08930 (Spain); Stchakovsky, Michel [HORIBA Jobin Yvon, Thin Film Division, Chilly-Mazarin 91380 (France)

    2008-09-30

    Hafnium oxide (HfO{sub 2}) has attracted much interest as high-k material of choice for gate oxide replacement in future CMOS technologies and for its use in optical coating technology. The determination of optical properties, like refractive index and bandgap, is focus of intense research, since the optical constants of HfO{sub 2} depend on the physical microstructure and the deposition methods and conditions. In the present study optical characterization of very thin HfO{sub 2} films deposited by plasma ion assisted deposition and annealed at different temperatures is carried out. The characterization is performed using ellipsometric measurements in the spectral range from 1.5 to 8 eV and by using the Tauc-Lorentz and Cody-Lorentz dispersion models. In addition, direct inversion of the ellipsometric data is also carried out. The combination of the Cody-Lorentz model with Urbach tail results in the best description of the data and enables to determine meaningful parameters. On the other hand, the direct data inversion is shown to be useful to provide additional information like the presence of subgap absorption peaks and points out features associated to the crystallinity of the material.

  14. Thermal analysis and vibrational spectroscopic characterization of the boro silicate mineral datolite - CaBSiO4(OH).

    Science.gov (United States)

    Frost, Ray L; Xi, Yunfei; Scholz, Ricardo; Lima, Rosa Malena Fernandes; Horta, Laura Frota Campos; Lopez, Andres

    2013-11-01

    The objective of this work is to determine the thermal stability and vibrational spectra of datolite CaBSiO4(OH) and relate these properties to the structure of the mineral. The thermal analysis of datolite shows a mass loss of 5.83% over a 700-775°C temperature range. This mass loss corresponds to 1 water (H2O) molecules pfu. A quantitative chemical analysis using electron probe was undertaken. The Raman spectrum of datolite is characterized by bands at 917 and 1077cm(-1) assigned to the symmetric stretching modes of BO and SiO tetrahedra. A very intense Raman band is observed at 3498cm(-1) assigned to the stretching vibration of the OH units in the structure of datolite. BOH out-of-plane vibrations are characterized by the infrared band at 782cm(-1). The vibrational spectra are based upon the structure of datolite based on sheets of four- and eight-membered rings of alternating SiO4 and BO3(OH) tetrahedra with the sheets bonded together by calcium atoms.

  15. Synthesis, crystal structures, spectroscopic characterization and in vitro antidiabetic studies of new Schiff base Copper(II) complexes

    Indian Academy of Sciences (India)

    SUNDARAMURTHY SANTHA LAKSHMI; KANNAPPAN GEETHA; M GAYATHRI; GANESH SHANMUGAM

    2016-07-01

    Two new Schiff base copper(II) complexes, [CuL¹(tmen)] (1) and [Cu₂L₂² (tmen)] (2) {where, H₂L¹ = N-(salicylidene)-L-valine, H₂L² = N-(3,5-dichlorosalicylidene)-L-valine and tmen = N,N,N',N'- tetramethylethylene-1,2-diamine} have been synthesized and characterized by molar conductance, elemental analyses, VSM-RT, UV-Vis, FTIR, EPR, and CD spectra. Both the complexes were structurally characterized by single crystal XRD. The crystal structure of complex 1 displays a distorted square pyramidal geometry in which Schiff base is coordinated to the Cu(II) ion via ONO-donor in the axial mode, whereas, the chelating diamine displays axial and equatorial mode of binding via NN-donor atoms. The crystal structure of the complex 2 reveals a syn-anti mode of carboxylate bridged dinuclear complex, in which, the coordination geometry around Cu(1) is square pyramid and distorted square planar around Cu(2). The target complexes were screened for in vitro antidiabetic activity. Both the complexes showed good inhibitory activity for α-amylase and α-glucosidase.

  16. In situ characterization and analysis of Salmonella biofilm formation under meat processing environments using a combined microscopic and spectroscopic approach.

    Science.gov (United States)

    Wang, Huhu; Ding, Shijie; Wang, Guangyu; Xu, Xinglian; Zhou, Guanghong

    2013-11-01

    Salmonella biofilm on food-contact surfaces present on food processing facilities may serve as a source of cross-contamination. In our work, biofilm formation by multi-strains of meat-borne Salmonella incubated at 20 °C, as well as the composition and distribution of extracellular polymeric substances (EPS), were investigated in situ by combining confocal laser scanning microscopy (CLSM), scanning electron microscope (SEM), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and Raman spectroscopy. A standard laboratory culture medium (tryptic soy broth, TSB) was used and compared with an actual meat substrate (meat thawing-loss broth, MTLB). The results indicated that Salmonella grown in both media were able to form biofilms on stainless steel surfaces via building a three-dimensional structure with multilayers of cells. Although the number of biofilm cells grown in MTLB was less than that in TSB, the cell numbers in MTLB was adequate to form a steady and mature biofilm. Salmonella grown in MTLB showed "cloud-shaped" morphology in the mature biofilm, whereas when grown in TSB appeared "reticular-shaped". The ATR-FTIR and Raman analysis revealed a completely different chemical composition between biofilms and the corresponding planktonic cells, and some important differences in biofilms grown in MTLB and in TSB. Importantly, our findings suggested that the progress towards a mature Salmonella biofilm on stainless steel surfaces may be associated with the production of the EPS matrix, mainly consisting of polysaccharides and proteins, which may serve as useful markers of biofilm formation. Our work indicated that a combination of these non-destructive techniques provided new insights into the formation of Salmonella biofilm matrix. © 2013.

  17. Macroscopic and spectroscopic characterization of uranium(VI) sorption onto orthoclase and muscovite and the influence of competing Ca2+

    Science.gov (United States)

    Richter, Constanze; Müller, Katharina; Drobot, Björn; Steudtner, Robin; Großmann, Kay; Stockmann, Madlen; Brendler, Vinzenz

    2016-09-01

    The uranium(VI) sorption onto orthoclase and muscovite, representing the mineral groups of feldspars and micas as important components of the earth crust, was investigated in the presence and absence of Ca2+ under aerobic conditions. Batch experiments were accompanied by time-resolved laser-induced fluorescence spectroscopy (TRLFS) as well as in situ attenuated total reflection Fourier-transform infrared (ATR FT-IR) spectroscopy. The results indicate that the U(VI) sorption is reduced by Ca2+ at pH ⩾ 8 up to 30% due to the formation of the neutral aqueous Ca2UO2(CO3)3 (aq) complex. TRLFS measurements on the supernatant confirmed the predominance of this Ca2UO2(CO3)3 (aq) complex in accordance with thermodynamic calculations. Furthermore, TRLFS measurements on the mineral suspension as a function of pH (4-9) and Ca2+ revealed the existence of several species. Parallel factor analysis (PARAFAC) indicated the formation of three surface species totally. In the absence of Ca2+, the tbnd XOsbnd UO2+ and tbnd XOsbnd UO2CO3- surface complexes were formed, whereas the presence of Ca2+ leads to the formation of tbnd XOsbnd UO2+ and tbnd XOsbnd UO2OH as the formation of the aqueous Ca2UO2(CO3)3 (aq) complex reduces the free UO22+ concentration in the solution. In addition, ATR FT-IR spectroscopy confirmed an outer-sphere surface species in the absence of Ca2+. These experimental results were used for the assessment of surface complexation parameters to improve the basis for a mechanistic modeling of the sorption processes of U(VI) onto orthoclase and muscovite including the influence of Ca2+. Namely, logK tbnd XOsbnd UO2+ = 1.69 and logK tbnd XOsbnd UO2CO3- = 8.96 were determined for sorption onto orthoclase, whereas logK tbnd XOsbnd UO2+ = 0.41 and logK tbnd XOsbnd UO2CO3- = 8.71 best describe sorption onto muscovite in the absence of Ca2+.

  18. Isolation and spectroscopic characterization of Zn(II), Cu(II), and Pd(II) complexes of 1,3,4-thiadiazole-derived ligand

    Science.gov (United States)

    Karcz, Dariusz; Matwijczuk, Arkadiusz; Boroń, Bożena; Creaven, Bernadette; Fiedor, Leszek; Niewiadomy, Andrzej; Gagoś, Mariusz

    2017-01-01

    A series of complexes incorporating Zn(II), Cu(II), and Pd(II) ions, and 4-(5-heptyl-1,3,4-thiadiazol-2-yl)benzene-1,3-diol (L1) as model ligand, was synthesized in order to examine the nature of potential interactions between biologically active ligands, 1,3,4-thiadiazoles and metal ions with proven biological relevance. The structures of the compounds isolated were characterized using a number of spectroscopic methods including IR, Uv-vis, AAS, steady state and time-resolved fluorescence (TRF). The results obtained suggest that the L1-Zn(II) and L1-Pd(II) complexes consist of one molecule of L1 and one acetate ion acting as ligands, while the L1-Cu(II) complex adapts a 2:1 (L1: metal) stoichiometry. The coordination of L1 to metal ions occurs most likely via one of the deprotonated hydroxyl groups of the resorcinyl moiety and one of the N atoms of the thiadiazole heterocycle.

  19. Charge-transfer interaction of drug quinidine with quinol, picric acid and DDQ:Spectroscopic characterization and biological activity studies towards understanding the drug-receptor mechanism

    Institute of Scientific and Technical Information of China (English)

    Hala H. Eldaroti; Suad A. Gadir; Moamen S. Refat; Abdel Majid A. Adam

    2014-01-01

    Investigation of charge-transfer (CT) complexes of drugs has been recognized as an important phenomenon in understanding of the drug-receptor binding mechanism. Structural, thermal, morpholo-gical and biological behavior of CT complexes formed between drug quinidine (Qui) as a donor and quinol (QL), picric acid (PA) or dichlorodicyanobenzoquinone (DDQ) as acceptors were reported. The newly synthesized CT complexes have been spectroscopically characterized via elemental analysis;infrared (IR), Raman, 1H NMR and electronic absorption spectroscopy; powder X-ray diffraction (PXRD);thermogravimetric (TG) analysis and scanning electron microscopy (SEM). It was found that the obtained complexes are nanoscale, semi-crystalline particles, thermally stable and spontaneous. The molecular composition of the obtained complexes was determined using spectrophotometric titration method and was found to be 1:1 ratios (donor:acceptor). Finally, the biological activities of the obtained CT complexes were tested for their antibacterial activities. The results obtained herein are satisfactory for estimation of drug Qui in the pharmaceutical form.

  20. From nicotinate-containing layered double hydroxides (LDHs) to NAD coenzyme-LDH nanocomposites - Syntheses and structural characterization by various spectroscopic methods

    Science.gov (United States)

    Muráth, Szabolcs; Dudás, Csilla; Kukovecz, Ákos; Kónya, Zoltán; Sipos, Pál; Pálinkó, István

    2017-07-01

    The syntheses of nicotinate anion- and NAD coenzyme-layered double hydroxide (LDH) composites were performed with the aim of having the organic component among the layers. In-house prepared CaAl-LDHs were the host materials. Intercalation was attempted by direct ion exchange or by the dehydration-rehydration method applying aqueous solvent mixtures (containing ethanol, propanol, acetone, N,N-dimethylformamide). For structural characterization, beside X-ray diffractometry, X-ray photoelectron and IR spectroscopies, transmission and scanning electron microscopies as well as energy-dispersive X-ray analysis were used. Molecular modelling served for the visualization of the arrangements of the intercalated ions among the layers of the LDH samples. Although not all the intercalation methods and solvent mixtures led to intercalated composite materials, successful ones could be identified. The combination of spectroscopic methods helped in proposing sensible spatial arrangements for the intercalated anions. The NAD-CaAl-LDH composite proved to be an active catalyst in the oxidation of hydroquinone to 1,4-bezoquinoe in the presence of H2O2.

  1. Spectroscopic characterization of the competitive binding of Eu(III), Ca(II), and Cu(II) to a sedimentary originated humic acid

    Energy Technology Data Exchange (ETDEWEB)

    Marang, L.; Reiller, P.E. [CEA Saclay, Nucl Energy Div, DPC SECR, Lab Speciat Radionucleides and Mol, 91 - Gif sur Yvette (France); Marang, L.; Benedetti, M.F. [Univ Paris 07, Lab Geochim Eaux, IPGP UMR CNRS 7154, F-75205 Paris 13 (France); Eidner, S.; Kumke, M.U. [Univ Potsdam, Inst Chem, D-14476 Potsdam (Germany)

    2009-06-15

    The competition between REE, alkaline earth and d-transition metals for organic matter binding sites is still an open field of research; particularly, the mechanisms governing these phenomena need to be characterized in more detail. In this study, we examine spectroscopically the mechanisms of competitive binding of Eu(III)/Cu(II) and Eu(III)/Ca(II) pair to Gorleben humic acid (HA), as previously proposed in the framework of the NICA-Donnan model. The evolution of time-resolved laser induced luminescence spectra of humic-complexed Eu(Ill) showed two strikingly different environments for a comparable bound proportion for Cu(II) and Ca(II). Cu(II) seems to compete more effectively with Eu(III) inducing its release into the Donnan phase, and into the bulk solution as free Eu{sup 3+}. This is evidenced both by the shapes of the spectra and by the decrease in the luminescence decay times. In contrast with that, Ca(II) induces a modification of the HA structure, which enhances the luminescence of humic-bound Eu(III), and causes a minor modification of the chemical environment of the complexed rare earth ion. (authors)

  2. Spectroscopic and structural characterizations of novel water-soluble tetraperoxo and diperoxo[polyaminocarboxylato bis(N-oxido)]tantalate(V) complexes.

    Science.gov (United States)

    Bayot, Daisy; Tinant, Bernard; Devillers, Michel

    2004-09-20

    New water-soluble homoleptic peroxo complexes and heteroleptic peroxo-polyaminocarboxylato (PAC) complexes of tantalum(V) have been prepared. In the case of the peroxo-PAC complexes, the synthesis in the presence of excess H2O2 leads to the oxidation of the nitrogen atoms of the ligand into N-oxides. The compounds correspond to the general formula (gu)3[Ta(O2)2(LO2)] x xH2O (gu = guanidinium, L = edta or pdta) in which H4LO2 refers to the bis(N-oxide) derivative of the PAC ligand. The TaV complexes have been characterized on the basis of elemental and thermal analysis and by IR and 13C and 15N NMR spectroscopy. These last two spectroscopic methods have been used to suggest the coordination mode of the PAC ligand in the complexes. ESI mass spectrometry measurements have also been carried out for the peroxo-PAC compounds. The crystal structures of the homoleptic tetraperoxotantalate, (gu)3[Ta(O2)4] (1), and the heteroleptic complex, (gu)3[Ta(O2)2(edtaO2)] x 2.32H2O x 0.68H2O2 (2b), have been determined, showing, for both cases, an 8-fold-coordinated Ta atom surrounded either by four bidentate peroxides or by two peroxides and one tetradentate edtaO2 ligand. Copyright 2004 American Chemical Society

  3. Synthesis, physicochemical and spectroscopic characterization of copper(II)-polysaccharide pullulan complexes by UV-vis, ATR-FTIR, and EPR.

    Science.gov (United States)

    Mitić, Zarko; Cakić, Milorad; Nikolić, Goran M; Nikolić, Ružica; Nikolić, Goran S; Pavlović, Radmila; Santaniello, Enzo

    2011-02-15

    Bioactive copper(II) complexes with polysaccharides, like pullulan and dextran, are important in both veterinary and human medicine for the treatment of hypochromic microcitary anemia and hypocupremia. In aqueous alkaline solutions, Cu(II) ion forms complexes with the exopolysaccharide pullulan and its reduced low-molecular derivative. The metal content and the solution composition depend on pH, temperature, and time of the reaction. The complexing process begins in a weak alkali solution (pH >7) and involves OH groups of pullulan monomer (glucopyranose) units. Complexes of Cu(II) ion with reduced low-molecular pullulan (RLMP, M(w) 6000 g mol(-1)) were synthesized in water solutions, at the boiling temperature and at different pH values ranging from 7.5 to 12. The Cu(II) complex formation with RLMP was analyzed by UV-vis spectrophotometry and other physicochemical methods. Spectroscopic characterizations (ATR-FTIR, FT-IRIS, and EPR) and spectra-structure correlation of Cu(II)-RLMP complexes were also carried out.

  4. Cytotoxic activity, X-ray crystal structures and spectroscopic characterization of cobalt(II), copper(II) and zinc(II) coordination compounds with 2-substituted benzimidazoles.

    Science.gov (United States)

    Sánchez-Guadarrama, Obdulia; López-Sandoval, Horacio; Sánchez-Bartéz, Francisco; Gracia-Mora, Isabel; Höpfl, Herbert; Barba-Behrens, Noráh

    2009-09-01

    Herein we present the synthesis, structural and spectroscopic characterization of coordination compounds of cobalt(II), copper(II) and zinc(II) with 2-methylbenzimidazole (2mbz), 2-phenylbenzimidazole (2phbz), 2-chlorobenzimidazole (2cbz), 2-benzimidazolecarbamate (2cmbz) and 2-guanidinobenzimidazole (2gbz). Their cytotoxic activity was evaluated using human cancer cell lines, PC3 (prostate), MCF-7 (breast), HCT-15 (colon), HeLa (cervic-uterine), SKLU-1 (lung) and U373 (glioblastoma), showing that the zinc(II) and copper(II) compounds [Zn(2mbz)(2)Cl(2)].0.5H(2)O, [Zn(2cmbz)(2)Cl(2)].EtOH, [Cu(2cmbz)Br(2)].0.7H(2)O and [Cu(2gbz)Br(2)] had significant cytotoxic activity. The isostructural cobalt(II) complexes showed not significant activity. The cytotoxic activity is related to the presence of halides in the coordination sphere of the metal ion. Recuperation experiments with HeLa cells, showed that the cells recuperated after removing the copper(II) compounds and, on the contrary, the cells treated with the zinc(II) compounds did not. These results indicate that the mode of action of the coordination compounds is different.

  5. Redox properties of structural Fe in clay minerals. 2. Electrochemical and spectroscopic characterization of electron transfer irreversibility in ferruginous smectite, SWa-1.

    Science.gov (United States)

    Gorski, Christopher A; Klüpfel, Laura; Voegelin, Andreas; Sander, Michael; Hofstetter, Thomas B

    2012-09-04

    Structural Fe in clay minerals is an important, albeit poorly characterized, redox-active phase found in many natural and engineered environments. This work develops an experimental approach to directly assess the redox properties of a natural Fe-bearing smectite (ferruginous smectite, SWa-1, 12.6 wt % Fe) with mediated electrochemical reduction (MER) and oxidation (MEO). By utilizing a suite of one-electron-transfer mediating compounds to facilitate electron transfer between structural Fe in SWa-1 and a working electrode, we show that the Fe2+/Fe3+ couple in SWa-1 is redox-active over a large range of potentials (from E(H) = -0.63 V to +0.61 V vs SHE). Electrochemical and spectroscopic analyses of SWa-1 samples that were subject to reduction and re-oxidation cycling revealed both reversible and irreversible structural Fe rearrangements that altered the observed apparent standard reduction potential (E(H)(ø)) of structural Fe. E(H)(ø)-values vary by as much as 0.56 V between SWa-1 samples with different redox histories. The wide range of E(H)-values over which SWa-1 is redox-active and redox history-dependent E(H)(ø)-values underscore the importance of Fe-bearing clay minerals as redox-active phases in a wide range of redox regimes.

  6. Platinum(II) complexes with 5,7-disubstituted-1,2,4-triazolo [1,5-a]pyrimidines: Spectroscopical characterization and cytotoxic activity in vitro

    Science.gov (United States)

    Łakomska, Iwona; Fandzloch, Marzena; Popławska, Beata; Sitkowski, Jerzy

    2012-06-01

    Complexes of the types: cis-[PtI2(dptp)2] (1), cis-[PtI2(NH3)(dptp)] (2), trans-[PtI2(dptp)(dmso)] (3) and trans-[PtI2(dbtp)(dmso)] (4), where dptp = 5,7-diphenyl-1,2,4-triazolo[1,5-a]pyrimidine (dptp), dbtp = 5,7-ditertbutyl-1,2,4-triazolo[1,5-a]pyrimidine have been synthesized and characterized by infrared and multinuclear magnetic resonance spectroscopic techniques (1H, 13C, 15N, 195Pt). In 195Pt NMR, the cis-diiodo complexes were observed between -2601 ppm and -3261 ppm, while the trans coordination compounds were found at higher field (ca. -4389 ppm). In all cases significant 15N NMR shielding (92-95 ppm) were observed for N(3) atom indicating this nitrogen atom as a coordination site. The cis complexes have been assayed for antitumor activity in vitro against two human cell lines: A549 (non-small cell lung carcinoma) and T47D (breast cancer). The results indicate a moderate antiproliferative activity of (2) against human cancer lines.

  7. Analysis of bound-free fluorescence and improved characterization of the electronic and spectroscopic properties of the 11Σ{/u +} state of Cl2

    Science.gov (United States)

    Wörmer, J.; Möller, T.; Stapelfeldt, J.; Zimmerer, G.; Haaks, D.; Kampf, S.; Le Calvé, J.; Castex, M. C.

    1988-12-01

    Synchrotron radiation is used to selectively excite the chlorine molecule in the VUV spectral range. Stationary fluorescence spectra of the 11Σ{/u +} state are observed following primary excitation of 11Σ{/u +} and 21Σ{/u +}. The bound-free part of the spectra is analysed with the aid of quantum mechanical computer simulations. A potential energy curve is constructed which is an approximation of the adiabatic double well potential energy curve of the 11Σ{/u +} state. The inner well is characterized by T e =(73428±50) cm-1, r e =(1.85 ± 0.05) Å; for the outer well hold T e =(64631±50) cm-1, r e =(2.57±0.05) Å, ω e =(261±5) cm-1, ω e x e =(0.668±0.01) cm-1 (35Cl2; v'<30). The potential energy curve is successfully checked with fluorescence excitation spectra. Within the error limits, the results of a former synchrotron radiation study are verified. It is ruled out, that the Cl2 “γ-state” recently observed with laser spectroscopic methods, can be attributed to the outer well of 11Σ{/u +}.

  8. Structural and spectroscopic characterization of 2-mesityl-1H-benzo[d]imidazol-3-ium chloride: a combined experimental and theoretical analysis.

    Science.gov (United States)

    Özdemir, Namık

    2012-06-01

    The title molecular salt, 2-mesityl-1H-benzo[d]imidazol-3-ium chloride (C(16)H(17)N(2)(+)·Cl-), was synthesized unexpectedly from the reaction of N-[(1E)-mesitylmethylene]benzene-1,2-diamine and CoCl(2)·6H(2)O, and characterized by elemental analysis, (1)H NMR and FT-IR spectroscopies, and single-crystal X-ray diffraction technique. In addition, quantum chemical calculations employing density functional theory (DFT) method with the 6-311++G(d,p) basis set were performed to study the molecular, spectroscopic and some electronic structure properties of the title compound, and the results were compared with the experimental findings. The computational result shows that the optimized geometry can well reproduce the crystal structural parameters. The intermolecular proton transfer process between the ionic (C(16)H(17)N(2)(+)·Cl-) and nonionic forms (C(16)H(16)N(2)·HCl) of the title salt is investigated and found to be almost barierless with an energy value of 0.20 kcal mol(-1). The NLO properties of the compound are bigger than those of urea. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. Synthesis, spectroscopic characterization and structural investigations of a new charge transfer complex of 2,6-diaminopyridine with 3,5-dinitrobenzoic acid: DNA binding and antimicrobial studies

    Science.gov (United States)

    Khan, Ishaat M.; Ahmad, Afaq; Kumar, Sarvendra

    2013-03-01

    A new charge transfer (CT) complex [(DAPH)+(DNB)-] consisting of 2,6-diaminopyridine (DAP) as donor and 3,5-dinitrobenzoic acid (DNB-H) as acceptor, was synthesized and characterized by FTIR, 1H and 13C NMR, ESI mass spectroscopic and X-ray crystallographic techniques. The hydrogen bonding (N+-H⋯O-) plays an important role to consolidate the cation and anion together. CT complex shows a considerable interaction with Calf thymus DNA. The CT complex was also tested for its antibacterial activity against two Gram-positive bacteria Staphylococcus aureus and Bacillus subtilis and two Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa strains by using Tetracycline as standard, and antifungal property against Aspergillus niger, Candida albicans, and Penicillium sp. by using Nystatin as standard. The results were compared with standard drugs and significant conclusions were obtained. A polymeric net work through H-bonding interactions between neighboring moieties was observed. This has been attributed to the formation of 1:1 type CT complex.

  10. Pyridine adsorption on NiSn/MgO-Al2O3: An FTIR spectroscopic study of surface acidity

    Science.gov (United States)

    Penkova, Anna; Bobadilla, Luis F.; Romero-Sarria, Francisca; Centeno, Miguel A.; Odriozola, José A.

    2014-10-01

    The acid-base properties of MgO-Al2O3 supports and NiSn/MgO-Al2O3 catalysts were evaluated by IR spectroscopy using pyridine as a probe molecule. The results indicate that only Lewis acid sites were detected on the surface of the supports as well as on the catalysts. Nevertheless, Brønsted acid sites were not detected. In the support without MgO three kinds of coordinatively unsaturated acid sites were detected: Al3+ cations occupying octahedral, tetrahedral and tetrahedral with cationic vacancy in the neighbourhood. The last sites appear as the strongest. Moreover, they are able to activate the pyridine molecules leading to the formation of an intermediate α-pyridone complex. When MgO or NiO were added to the alumina, the number and strength of the Lewis acid sites decreased and significant changes were observed in the tetrahedral sites with adjoining cation vacancies. The incorporation of the Mg2+ cations into the alumina's structure takes place on the vacant tetrahedral positions, forming spinel MgAl2O4. As a result, the fraction of tetrahedral sites with adjoining cationic vacancy diminished and the intermediate α-pyridone complex in the support with the highest MgO loading was hardly detected. The addition of Ni2+ cations leads to the filling of the free octahedral positions, resulting in the formation of a NiAl2O4 spinel structure and the thermal stability of the α-pyridone species decreases. In the catalysts, the progressive reduction of the number and strength of the Lewis acid sites is due to a competitive formation of the two types of MgAl2O4 and NiAl2O4 spinels. In the catalyst NiSn/30MgO-Al2O3 no cationic vacancies were detected and the surface reaction with α-pyridone formation did not occur.

  11. Infrared and Fluorescence Spectroscopic Investigations of the Acyl Surface Modification of Hydrogel Beads for the Deposition of a Phospholipid Coating.

    Science.gov (United States)

    Grossutti, Michael; Seenath, Ryan; Lipkowski, Jacek

    2015-10-27

    The scaffolded vesicle has been employed as an alternative means of developing natural model membranes and envisioned as a potential nutraceutical transporter. Furthering the research of the scaffolded vesicle system, a nucleophilic substitution reaction was implemented to form an ester linkage between palmitate and terminal hydroxyl groups of dextran in order to hydrophobically modify the hydrogel scaffold. An average tilt angle of 38° of the hydrophobic palmitate modifying layer on the surface of the hydrogel was determined from dichroic ratios obtained from infrared spectra collected in the attenuated total reflection (ATR) configuration. ATR-IR studies of the DMPC-coated acylated hydrogel demonstrated that the hydrocarbon chains of the DMPC coating was similar to those of the DMPC bilayers and that the underlying palmitate layer had a negligible effect on the average tilt angle (26°) of the DMPC coating. The permeability of this acylated hydrogel was investigated with fluorescence spectroscopy and the terbium/dipicolinic acid assay. The hydrophobic modification on the surface of the hydrogel bead allowed for an efficient deposition of a DMPC layer that served as an impermeable barrier to terbium efflux. About 72% of DMPC-coated acylated hydrogel beads showed ideal barrier properties. The remaining 28% were leaking, but the half-life of terbium efflux of the DMPC-coated acylated hydrogel was increasing, and the total amount of leaked terbium was decreasing with the incubation time. The half-life time and the retention were considered a marked improvement relative to past scaffolded vesicle preparations. The process of acylating hydrogel beads for efficient DMPC deposition has been identified as another viable method for controlling the permeability of the scaffolded vesicle.

  12. STUDIES ON SURFACE CHARACTERIZATION AND ECOMATERIAL SHEET DEGRADATION OF BASALT FIBERS BY PLASMA TREATMENTS AND WOOD FIBERS

    Institute of Scientific and Technical Information of China (English)

    GuangjianWang; YajieGuo; DekuShang; linnaHu; ZhenhuaGuo; KailiangZhang

    2004-01-01

    plasma surtace modification (Argon: Hydrogen=0.6:0.4) of basalt fibers was mvestigated and the element contents of basalt and wood fibers were determined by X-ray energy dispersion spectroscope (EDS). configuration of basalt fibers was described by means of confocal Laser Raman microRaman spectrometer and Fourier transform infrared spectroscopy. And the morphology of fiber surface was studied with scanning electron microscope (SEM). The modified samples were characterized by X-ray photoelectron spectra (XPS). The results showed that the roughness of basalt fibers was increased with the increase of exposure time of plasma. At the same time the wettability and surface characteristics such as active groups of NH2, OH were improved as well. Basalt fibers were of good chemical stability, better mechanism intension and thermo-stability etc. They mainly consist of [SiO4]4-, [Si2O6]4-,[Si2O5]2-. Further experiments demostrated that they were degraded into edaphic matrix after use. Therefore, they were environmentally friendly.

  13. Surface characterization of polymers by inverse gas chromatography

    Directory of Open Access Journals (Sweden)

    ALEKSANDRA B. NASTASOVIC

    2007-04-01

    Full Text Available An inverse gas chromatographic (IGC study of the sorption properties of macroporous crosslinked poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate, PGME, and PGME modified with ethylene diamine, PGME-en, was presented. At infinite dilution, the thermodynamic parameters of adsorption, the dispersive components of the surface free energies, the acid/base constants and the interaction parameters for the initial and modified copolymer samples were investigated. The adsorption isotherms determined by IGC under conditions of finite surface coverage were used to estimate the surface area, the isosteric heat of adsorption and the adsorption energy distribution on the surface of the initial and modified copolymer samples.

  14. Study of a controlled release polymeric system based on Pluronic P123: Spectroscopic characterization and theoretical model approach

    Science.gov (United States)

    Arroyo, E.; Luque, P. A.; Cosio, M.; Soto, C.; Villarreal, R.; Nava, O.; Olivas, A.

    2017-06-01

    This work reports the profiles of drug release systems based on different polymers for the potential use as a skin anti-inflammatory. The materials used for the encapsulation of indomethacin were Pluronic P123 with various combinations of poly-ethylene-glycol and poly-N-vinyl pyrrolidone. These systems were characterized via Fourier transform infrared spectrometry and high resolution transmission electron microscopy. The morphology showed the treated polymers as spheres. Drug loadings were carried out via the absorption in solution method; this load was of a 1:10 wt ratio indomethacin to polymers. Drug release tests were performed via the dialysis method pH 7.2 phosphate buffered saline at 32 °C. The drug concentration was determined via UV-Vis spectroscopy, and additionally, a theoretical model was developed based on diffusion equations to describe the phenomenon. Comparison between the experimental results and theory was close to 5%.

  15. Synthesis, spectroscopic characterization and solution behavior of new tin tetrachloride adducts with γ-keto allyl phosphonates

    Science.gov (United States)

    Elleuch, Haitham; Sanhoury, M. A. K.; Rezgui, F.

    2017-01-01

    Four new octahedral complexes of the type [SnCl4L2] (L = γ-keto allyl phosphonate) (1-4) were prepared and characterized by multinuclear (1H, 13C, 31P and 119Sn) NMR, IR spectroscopy and elemental analysis. The NMR data show, as expected, that these complexes exist in solution as mixtures of cis and trans isomers. More importantly, the solution structure was confirmed by 119Sn NMR spectra which show two triplets corresponding to the two isomers. In addition, the solution behavior of these complexes in the presence of excess ligand was studied by variable temperature NMR using the coalescence temperature method. The metal-ligand exchange activation energies were therefore determined and found to be in the range 57-60 kJ/mol. The effect of remote substituents on the metal-ligand interaction was studied and compared with closely related tin-phosphoryl complexes.

  16. Spectroscopic and computational characterization of CuII-OOR (R = H or cumyl) complexes bearing a Me6-tren ligand.

    Science.gov (United States)

    Choi, Yu Jin; Cho, Kyung-Bin; Kubo, Minoru; Ogura, Takashi; Karlin, Kenneth D; Cho, Jaeheung; Nam, Wonwoo

    2011-03-14

    A copper(II)-hydroperoxo complex, [Cu(Me(6)-tren)(OOH)](+) (2), and a copper(ii)-cumylperoxo complex, [Cu(Me(6)-tren)(OOC(CH(3))(2)Ph)](+) (3), were synthesized by reacting [Cu(Me(6)-tren)(CH(3)CN)](2+) (1) with H(2)O(2) and cumyl-OOH, respectively, in the presence of triethylamine. These intermediates, 2 and 3, were successfully characterized by various physicochemical methods such as UV-vis, ESI-MS, resonance Raman and EPR spectroscopies, leading us to propose structures of the Cu(II)-OOR species with a trigonal-bipyramidal geometry. Density functional theory (DFT) calculations provided geometric and electronic configurations of 2 and 3, showing trigonal bipyramidal copper(II)-OOR geometries. These copper(II)-hydroperoxo and -cumylperoxo complexes were inactive in electrophilic and nucleophilic oxidation reactions.

  17. Preparation, spectroscopic characterization and antimicrobial activities of mixed metal (Sb and Bi) bridged derivatives with mixed sulfur donor ligands

    Science.gov (United States)

    Joshi, Sapana; Chauhan, H. P. S.; Carpenter, Nitin

    2017-01-01

    This article explores the syntheses of six mixed metal derivatives of antimony(III) and bismuth(III) by the reaction of ethane-1,2-dithiol and metal bis derivatives of dithiocarbamates and/or dithiophosphates ligands in 1:1:1 M stoichiometry. These derivatives have been characterized by physicochemical [elemental analysis (C, H, N, S, Sb and Bi), molecular weight and melting point determinations], spectral [UV-Visible, FTIR, NMR (1H, 13C and 31P)], powder X-ray diffraction studies. These derivatives have nano-ranged crystallite size (8.18-18.04 nm) with monoclinic crystal system. All the synthesized derivatives have two metal centers (Sb and Bi) which elevate the zone of inhibition against four bacterial and two fungal species as compared to single metal species (metal precursors) as well as standard drugs.

  18. AFM characterization of the shape of surface structures with localization factor.

    Science.gov (United States)

    Bonyár, Attila

    2016-08-01

    Although with the use of scanning probe microscopy (SPM) methods the topographical imaging of surfaces is now widely available, the characterization of surface structures, especially their shape, and the processes which change these features is not trivial with the existing surface describing parameters. In this work the application of a parameter called localization factor is demonstrated for the quantitative characterization of surface structures and for processes which alter the shape of these structures. The theory and optimal operation range of this parameter are discussed with three application examples: microstructure characterization of gold thin films, characterization of the changes in the grain structure of these films during thermal annealing, and finally, characterization of the oxidation processes on a polished tin surface.

  19. Acid/base bifunctional carbonaceous nanomaterial with large surface area: Preparation, characterization, and adsorption properties for cationic and anionic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Li, Kai; Ma, Chun–Fang; Ling, Yuan; Li, Meng [Department of Chemistry, Faculty of Material Science and Chemistry, China University of Geosciences, Wuhan 430074 (China); Gao, Qiang, E-mail: gaoqiang@cug.edu.cn [Department of Chemistry, Faculty of Material Science and Chemistry, China University of Geosciences, Wuhan 430074 (China); Engineering Research Center of Nano-Geo Materials of Ministry of Education, China University of Geosciences, Wuhan 430074 (China); Luo, Wen–Jun, E-mail: heartnohome@yahoo.com.cn [Department of Chemistry, Faculty of Material Science and Chemistry, China University of Geosciences, Wuhan 430074 (China)

    2015-07-15

    Nanostructured carbonaceous materials are extremely important in the nano field, yet developing simple, mild, and “green” methods that can make such materials possess large surface area and rich functional groups on their surfaces still remains a considerable challenge. Herein, a one-pot and environment-friendly method, i.e., thermal treatment (180 °C; 18 h) of water mixed with glucose and chitosan (CTS), has been proposed. The resultant carbonaceous nanomaterials were characterized by field emitting scanning electron microscope, N{sub 2} adsorption/desorption, Fourier transform infrared spectroscope, X-ray photoelectron spectroscopy, and zeta-potential analysis. It was found that, in contrast to the conventional hydrothermally carbonized product from pure glucose, with low surface area (9.3 m{sup 2} g{sup −1}) and pore volume (0.016 cm{sup 3} g{sup −1}), the CTS-added carbonaceous products showed satisfactory textural parameters (surface area and pore volume up to 254 m{sup 2} g{sup −1} and 0.701 cm{sup 3} g{sup −1}, respectively). Moreover, it was also interestingly found that these CTS-added carbonaceous products possessed both acidic (–COOH) and basic (–NH{sub 2}) groups on their surfaces. Taking the advantages of large surface area and –COOH/–NH{sub 2} bifunctional surface, the carbonaceous nanomaterials exhibited excellent performance for adsorptions of cationic compound (i.e., methylene blue) at pH 10 and anionic compound (i.e., acid red 18) at pH 2, respectively. This work not only provides a simple and green route to prepare acid/base bifunctional carbonaceous nanomaterials with large surface area but also well demonstrates their potential for application in adsorption. - Highlights: • A simple and green method was proposed to prepare carbon nanomaterials. • The carbon product showed acid/base bifunctional surface with large surface area. • The carbon material could efficiently adsorb both cationic and anionic compounds.

  20. {sup 13}C-METHYL FORMATE: OBSERVATIONS OF A SAMPLE OF HIGH-MASS STAR-FORMING REGIONS INCLUDING ORION-KL AND SPECTROSCOPIC CHARACTERIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Favre, Cécile; Bergin, Edwin A.; Crockett, Nathan R.; Neill, Justin L. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Carvajal, Miguel [Dpto. Física Aplicada, Unidad Asociada CSIC, Facultad de Ciencias Experimentales, Universidad de Huelva, E-21071 Huelva (Spain); Field, David [Department of Physics and Astronomy, University of Aarhus, Ny Munkegade 120, DK-8000 Aarhus C (Denmark); Jørgensen, Jes K.; Bisschop, Suzanne E. [Centre for Star and Planet Formation, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen Ø (Denmark); Brouillet, Nathalie; Despois, Didier; Baudry, Alain [Univ. Bordeaux, LAB, UMR 5804, F-33270, Floirac (France); Kleiner, Isabelle [Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA), CNRS, UMR 7583, Université de Paris-Est et Paris Diderot, 61, Av. du Général de Gaulle, F-94010 Créteil Cedex (France); Margulès, Laurent; Huet, Thérèse R.; Demaison, Jean, E-mail: cfavre@umich.edu, E-mail: miguel.carvajal@dfa.uhu.es [Laboratoire de Physique des Lasers, Atomes et Molécules, UMR CNRS 8523, Université Lille I, F-59655 Villeneuve d' Ascq Cedex (France)

    2015-01-01

    We have surveyed a sample of massive star-forming regions located over a range of distances from the Galactic center for methyl formate, HCOOCH{sub 3}, and its isotopologues H{sup 13}COOCH{sub 3} and HCOO{sup 13}CH{sub 3}. The observations were carried out with the APEX telescope in the frequency range 283.4-287.4 GHz. Based on the APEX observations, we report tentative detections of the {sup 13}C-methyl formate isotopologue HCOO{sup 13}CH{sub 3} toward the following four massive star-forming regions: Sgr B2(N-LMH), NGC 6334 IRS 1, W51 e2, and G19.61-0.23. In addition, we have used the 1 mm ALMA science verification observations of Orion-KL and confirm the detection of the {sup 13}C-methyl formate species in Orion-KL and image its spatial distribution. Our analysis shows that the {sup 12}C/{sup 13}C isotope ratio in methyl formate toward the Orion-KL Compact Ridge and Hot Core-SW components (68.4 ± 10.1 and 71.4 ± 7.8, respectively) are, for both the {sup 13}C-methyl formate isotopologues, commensurate with the average {sup 12}C/{sup 13}C ratio of CO derived toward Orion-KL. Likewise, regarding the other sources, our results are consistent with the {sup 12}C/{sup 13}C in CO. We also report the spectroscopic characterization, which includes a complete partition function, of the complex H{sup 13}COOCH{sub 3} and HCOO{sup 13}CH{sub 3} species. New spectroscopic data for both isotopomers H{sup 13}COOCH{sub 3} and HCOO{sup 13}CH{sub 3}, presented in this study, have made it possible to measure this fundamentally important isotope ratio in a large organic molecule for the first time.

  1. Extraction and coordination studies of a carbonyl-phosphine oxide scorpionate ligand with uranyl and lanthanide(III) nitrates: structural, spectroscopic and DFT characterization of the complexes.

    Science.gov (United States)

    Matveeva, Anna G; Vologzhanina, Anna V; Goryunov, Evgenii I; Aysin, Rinat R; Pasechnik, Margarita P; Matveev, Sergey V; Godovikov, Ivan A; Safiulina, Alfiya M; Brel, Valery K

    2016-03-28

    Hybrid scorpionate ligand (OPPh2)2CHCH2C(O)Me (L) was synthesized and characterized by spectroscopic methods and X-ray diffraction. The selected coordination chemistry of L with UO2(NO3)2 and Ln(NO3)3 (Ln = La, Nd, Lu) has been evaluated. The isolated mono- and binuclear complexes, namely, [UO2(NO3)2L] (1), [{UO2(NO3)L}2(μ2-O2)]·EtOH (2), [La(NO3)3L2]·2.33MeCN (3), [Nd(NO3)3L2]·3MeCN (4), [Nd(NO3)2L2]+·(NO3)−·EtOH (5) and [Lu(NO3)3L2] (6) have been characterized by IR spectroscopy and elemental analysis. Single-crystal X-ray structures have been determined for complexes 1-5. Intramolecular intraligand π-stacking interactions between two phenyl fragments of the coordinated ligand(s) were observed in all complexes 1-5. The π-stacking interaction energy was estimated from Bader's AIM theory calculations performed at the DFT level. Solution properties have been examined using IR and multinuclear ((1)H, (13)C, and (31)P) NMR spectroscopy in CD3CN and CDCl3. Coordination modes of L vary with the coordination polyhedron of the metal and solvent nature showing many coordination modes: P(O),P(O), P(O),P(O),C(O), P(O),C(O), and P(O). Preliminary extraction studies of U(VI) and Ln(III) (Ln = La, Nd, Ho, Yb) from 3.75 M HNO3 into CHCl3 show that scorpionate L extracts f-block elements (especially uranium) better than its unmodified prototype (OPPh2)2CH2.

  2. Electrical characterization, phase transition and vibrational spectroscopic investigations of a new organic-inorganic material (C7H10NO)SnCl3

    Science.gov (United States)

    Karoui, Sahel; Chouaib, Hassen; Kamoun, Slaheddine

    2017-10-01

    The X-ray powder analysis, thermogravimetric analysis, differential scanning calorimetry analysis, solid CP-MAS 13C NMR characterization, vibrational spectroscopy and complex impedance spectroscopic data have been carried out on (C7H10NO)SnCl3 compound. The results show that this compound exhibits a phase transition at 314 K which was characterized by 1H NMR between 298 and 336 K, differential scanning calorimetry (DSC), X-rays powder diffraction, Raman spectroscopy and dielectric measurements. The temperature dependence of the 1H NMR spectrum for (C7H10NO)SnCl3 could be explained by invoking reorientation of ammonium group of the 2-methoxyanilinium cation. The most important changes are observed for two lines at 3087 cm-1 and 3175 cm-1 (at room temperature) issued from asymmetric and symmetric stretching vibrations of νs(NH3) and νas(NH3) band, respectively. AC and DC conductivities, complex dielectric permittivity ε*(ω) and complex electrical modulus M*(ω) were respectively studied as temperature and frequency functions. Moreover, the temperature dependence of the DC conductivity and relaxation frequency followed the Arrhenius relation. The frequency dependence of the real part of the AC conductivity in both phases follows the Jonscher's universal dynamic law: σTot.(ω,T) = σDC(T) + B(T) ωS(T). The close values of activation energies, obtained from the thermal behavior of the conductivity and the relaxation time confirm that the transport is through ion-hopping mechanism.

  3. Structural and spectroscopic characterization of iron(II), cobalt(II), and nickel(II) ortho-dihalophenolate complexes: insights into metal-halogen secondary bonding.

    Science.gov (United States)

    Machonkin, Timothy E; Boshart, Monica D; Schofield, Jeremy A; Rodriguez, Meghan M; Grubel, Katarzyna; Rokhsana, Dalia; Brennessel, William W; Holland, Patrick L

    2014-09-15

    Metal complexes incorporating the tris(3,5-diphenylpyrazolyl)borate ligand (Tp(Ph2)) and ortho-dihalophenolates were synthesized and characterized in order to explore metal-halogen secondary bonding in biorelevant model complexes. The complexes Tp(Ph2)ML were synthesized and structurally characterized, where M was Fe(II), Co(II), or Ni(II) and L was either 2,6-dichloro- or 2,6-dibromophenolate. All six complexes exhibited metal-halogen secondary bonds in the solid state, with distances ranging from 2.56 Å for the Tp(Ph2)Ni(2,6-dichlorophenolate) complex to 2.88 Å for the Tp(Ph2)Fe(2,6-dibromophenolate) complex. Variable temperature NMR spectra of the Tp(Ph2)Co(2,6-dichlorophenolate) and Tp(Ph2)Ni(2,6-dichlorophenolate) complexes showed that rotation of the phenolate, which requires loss of the secondary bond, has an activation barrier of ~30 and ~37 kJ/mol, respectively. Density functional theory calculations support the presence of a barrier for disruption of the metal-halogen interaction during rotation of the phenolate. On the other hand, calculations using the spectroscopically calibrated angular overlap method suggest essentially no contribution of the halogen to the ligand-field splitting. Overall, these results provide the first quantitative measure of the strength of a metal-halogen secondary bond and demonstrate that it is a weak noncovalent interaction comparable in strength to a hydrogen bond. These results provide insight into the origin of the specificity of the enzyme 2,6-dichlorohydroquinone 1,2-dioxygenase (PcpA), which is specific for ortho-dihalohydroquinone substrates and phenol inhibitors.

  4. Synthesis, characterization, and spectroscopic investigation of new iron(III) and copper(II) complexes of a carboxylate rich ligand and their interaction with carbohydrates in aqueous solution.

    Science.gov (United States)

    Stewart, Christopher D; Arman, Hadi; Bawazir, Huda; Musie, Ghezai T

    2014-10-20

    New tetra-iron(III) (K4[1]·25H2O·(CH3)2CO and K3[2]·3H2O·(OH)) and di-copper(II) (Na3[3]·5H2O) complexes as carbohydrate binding models have been synthesized and fully characterized used several techniques including single crystal X-ray crystallography. Whereas K4[1]·25H2O·(CH3)2CO and Na3[3]·5H2O are completely water-soluble, K3[2]·3H2O·(OH) is less soluble in all common solvents including water. The binding of substrates, such as d-mannose, d-glucose, d-xylose, and xylitol with the water-soluble complexes in different reaction conditions were investigated. In aqueous alkaline media, complexes K4[1]·25H2O·(CH3)2CO and Na3[3]·5H2O showed coordination ability toward the applied substrates. Even in the presence of stoichiometric excess of the substrates, the complexes form only 1:1 (complex/substrate) molar ratio species in solution. Apparent binding constants, pKapp, values between the complexes and the substrates were determined and specific mode of substrate binding is proposed. The pKapp values showed that d-mannose coordinates strongest to K4[1]·25H2O·(CH3)2CO and Na3[3]·5H2O. Syntheses, characterizations and detailed substrate binding study using spectroscopic techniques and single crystal X-ray diffraction are reported.

  5. Surface-enhanced Raman spectroscopic studies of the Au-pentacene interface: A combined experimental and theoretical investigation

    Science.gov (United States)

    Adil, D.; Guha, S.

    2013-07-01

    It has recently been shown [D. Adil and S. Guha, J. Phys. Chem. C 116, 12779 (2012)], 10.1021/jp3031804 that a large enhancement in the Raman intensity due to surface-enhanced Raman scattering (SERS) is observed from pentacene when probed through the Au contact in organic field-effect transistors (OFET) structures. Here, the SERS spectrum is shown to exhibit a high sensitivity to disorder introduced in the pentacene film by Au atoms. The Raman signature of the metal-semiconductor interface in pentacene OFETs is calculated with density-functional theory by explicitly considering the Au-pentacene interaction. The observed enhancement in the 1380 cm-1 and the 1560 cm-1 regions of the experimental Raman spectrum of pentacene is successfully modeled by Au-pentacene complexes, giving insights into the nature of disorder in the pentacene sp2 network. Finally, we extend our previous work on high-operating voltage pentacene OFETs to low-operating voltage pentacene OFETs. No changes in the SERS spectra before and after subjecting the OFETs to a bias stress are observed, concurrent with no degradation in the threshold voltage. This shows that bias stress induced performance degradation is, in part, caused by field-induced structural changes in the pentacene molecule. Thus, we confirm that the SERS spectrum can be used as a visualization tool for correlating transport properties to structural changes, if any, in organic semiconductor based devices.

  6. Infrared reflection absorption spectroscopic study on the adsorption structures of acrylonitrile on Ag(111) and Ag(110) surfaces

    Science.gov (United States)

    Osaka, Naoki; Akita, Masato; Hiramoto, Shuji; Itoh, Koichi

    1999-06-01

    Infrared reflection-absorption spectra in CN stretching, CH 2 out-of-plane wagging and CH 2 twisting vibration regions were measured for acrylonitrile (CH 2CHCN) exposed to Ag(111) and Ag(110) in increasing amounts at 77 K. The adsorbate on Ag(111) takes on a series of discrete adsorption states; i.e., an isolated state, associated states, and ordered and amorphous multilayer states. The adsorbate on Ag(110) at lower exposures is in a state with the CN group weakly coordinated to a silver atom (or silver atoms). The adsorbate on Ag(110) takes the associated state and the amorphous multilayer at larger exposures. On raising the temperature to 96 K, the amorphous states on both Ag(111) and Ag(110) are converted to the ordered multilayer. The desorption temperature of the ordered multilayer is below 99 K for Ag(110), while the temperature is above 107 K for Ag(111); the result indicates the effect of the surface morphology on the stability of the ordered state.

  7. STM characterization of MOVPE-prepared silicon surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Kleinschmidt, Peter; Brueckner, Sebastian; Luczak, Johannes; Supplie, Oliver; Dobrich, Anja; Doescher, Henning; Hannappel, Thomas [Helmholtz-Zentrum Berlin fuer Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin (Germany)

    2011-07-01

    The clean Si(100) surface reconstructs by forming dimers, thus reducing the number of dangling bonds at the surface. In the MOVPE environment hydrogen is commonly used as process gas, which leads to a monohydride silicon surface with a 2 x 1 unit cell consisting of H-Si-Si-H dimers. Even so, the quality of the surface can vary dramatically depending on process conditions. In general, annealing in hydrogen leads to a two-domain surface structure with monoatomic steps, where the resulting structure also strongly depends on misorientation. We find process conditions for preparation of Si(100) surfaces with 0.1 , 2 and 6 offcut where a strong preference for one domain is obtained, making the resulting surfaces ideal substrates for III-V-on-Si epitaxy. A process consisting of deoxidation, homoepitaxial buffer layer growth and annealing is found to result in D{sub A}-type double layer steps for 0.1 , and D{sub B}-type double layer steps for 6 offcut. The identical process leads to single layer steps for 2 offcut. Here, we obtain D{sub A}-type double layer steps by a modified process which includes a slow cooling phase after the annealing step. Our results, verified by scanning tunneling microscopy, low energy electron diffraction and Fourier-transform infrared spectroscopy, are in sharp contrast to the clean and the hydrogenated Si(100) surface prepared in UHV.

  8. AKD AND ASA MODEL SURFACES: PREPARATION AND CHARACTERIZATION

    Directory of Open Access Journals (Sweden)

    Janne Laine

    2007-11-01

    Full Text Available Model surfaces of alkyl ketene dimer (AKD and alkenyl succinic anhyd-ride (ASA were prepared by casting and spin-coating methods. The surface chemical composition and surface topography were investigated by XPS, ellipsometry, AFM and contact angle studies. Spin-coating resulted in layered structure of AKD and ASA surfaces; the molecular layer thickness of both AKD and ASA was found to be ca. 2.5 nm. To achieve a covering surface layer, an average thickness of ca. 35 nm was required. The rms roughness of the created surfaces was 1 - 6 nm. Colloidal probe adhesion measurements were performed to verify that the roughness was in a range suitable for these measurements. The high reactivity of ASA with water generated stability problems with the ASA layers and it has to be recognized that surface force measurements with ASA in aqueous environment are very difficult, if not impossible. How-ever, surfaces created in this way were found to be useful in providing explanations of earlier ASA adhesion studies. The contact angle measurements on ASA layers also indicated that it might be possible to asses the hydrolysis rate issues through a set of similar measurements.

  9. Preparation and characterization of low-defect surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, T.O.

    1991-12-01

    Silver crystal surfaces with low defect densities were prepared electrochemically from aqueous solutions using capillary-growth techniques. These surfaces had low rates for the nucleation of new silver layers. The impedance of these inert silver/aqueous silver nitrate interfaces was used to determine silver adatom concentration and water dipole reorientation energetics.

  10. Characterization of the normal microbiota of the ocular surface.

    Science.gov (United States)

    Willcox, Mark D P

    2013-12-01

    The ocular surface is continually exposed to the environment and as a consequence to different types of microbes, but whether there is a normal microbiota of the ocular surface remains unresolved. Using traditional microbial culture techniques has shown that microbiota, or whether the microbiota are only transiently present. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. In situ Fourier transform-infrared internal reflection spectroscopic analysis of hydrocarbon chain ordering of surfactants adsorbed at mineral oxide surfaces

    Science.gov (United States)

    Cross, William Murray

    The adsorption of surfactants at mineral oxide surfaces was investigated by in situ Fourier transform infrared internal reflection spectroscopy (FT-IR/IRS), and contact angle goniometry. FT-IR/IRS was used to determine both adsorption isotherms and the enthalpy of adsorption. Furthermore, the conformation and orientation of the hydrocarbon chain of SDS adsorbed at a sapphire internal reflection element (IRE) were determined. Contact angle goniometry was used to measure the effect of the surface phase of the surfactant on the hydrophobic character of sapphire surfaces in aqueous solutions. For SDS adsorbed by sapphire, in situ FT-IR/IRS experiments indicate that a surface phase transition occurs at an adsorption density of 2 to 3 x 10-10 mol/cm2 for both pD 2.9 and 6.9. This transition is characterized by a two to four wavenumber shift in the position of the asymmetric -CH2 stretching band. Based on solution spectroscopy studies, the surface phase was found to be similar to solution phase micelles and liquid crystals for adsorption densities less than the adsorption density of the surface phase transition. Whereas for adsorption densities in excess of the adsorption density of the surface phase transition, the surface phase resembled a solution phase coagel species. It was also found that the contact angle of an air bubble at the sapphire surface exhibited a sharp