WorldWideScience

Sample records for 2d ir spectroscopy

  1. Structure of a model salt bridge in solution investigated with 2D-IR spectroscopy

    CERN Document Server

    Huerta-Viga, Adriana; Amirjalayer, Saeed; Woutersen, Sander

    2013-01-01

    Salt bridges are known to be important for the stability of protein conformation, but up to now it has been difficult to study their geometry in solution. Here we characterize the spatial structure of a model salt bridge between guanidinium (Gdm+) and acetate (Ac-) using two-dimensional vibrational (2D-IR) spectroscopy. We find that as a result of salt bridging the infrared response of Gdm+ and Ac- change significantly, and in the 2D-IR spectrum, salt bridging of the molecules appears as cross peaks. From the 2D-IR spectrum we determine the relative orientation of the transition-dipole moments of the vibrational modes involved in the salt bridge, as well as the coupling between them. In this manner we reconstruct the geometry of the solvated salt bridge.

  2. A salt-bridge structure in solution revealed by 2D-IR spectroscopy.

    Science.gov (United States)

    Huerta-Viga, Adriana; Domingos, Sérgio R; Amirjalayer, Saeed; Woutersen, Sander

    2014-08-14

    Salt bridges are important interactions for the stability of protein conformations, but up to now it has been difficult to determine salt-bridge geometries in solution. Here we characterize the spatial structure of a salt bridge between guanidinium (Gdm(+)) and acetate (Ac(-)) using two-dimensional vibrational (2D-IR) spectroscopy. We find that as a result of salt bridge formation there is a significant change in the infrared response of Gdm(+) and Ac(-), and cross peaks between them appear in the 2D-IR spectrum. From the 2D-IR spectrum we determine the relative orientation of the transition-dipole moments of the vibrational modes of Gdm(+) and Ac(-), as well as the coupling between them. PMID:24676430

  3. Water of Hydration Dynamics in Minerals Gypsum and Bassanite: Ultrafast 2D IR Spectroscopy of Rocks.

    Science.gov (United States)

    Yan, Chang; Nishida, Jun; Yuan, Rongfeng; Fayer, Michael D

    2016-08-01

    Water of hydration plays an important role in minerals, determining their crystal structures and physical properties. Here ultrafast nonlinear infrared (IR) techniques, two-dimensional infrared (2D IR) and polarization selective pump-probe (PSPP) spectroscopies, were used to measure the dynamics and disorder of water of hydration in two minerals, gypsum (CaSO4·2H2O) and bassanite (CaSO4·0.5H2O). 2D IR spectra revealed that water arrangement in freshly precipitated gypsum contained a small amount of inhomogeneity. Following annealing at 348 K, water molecules became highly ordered; the 2D IR spectrum became homogeneously broadened (motional narrowed). PSPP measurements observed only inertial orientational relaxation. In contrast, water in bassanite's tubular channels is dynamically disordered. 2D IR spectra showed a significant amount of inhomogeneous broadening caused by a range of water configurations. At 298 K, water dynamics cause spectral diffusion that sampled a portion of the inhomogeneous line width on the time scale of ∼30 ps, while the rest of inhomogeneity is static on the time scale of the measurements. At higher temperature, the dynamics become faster. Spectral diffusion accelerates, and a portion of the lower temperature spectral diffusion became motionally narrowed. At sufficiently high temperature, all of the dynamics that produced spectral diffusion at lower temperatures became motionally narrowed, and only homogeneous broadening and static inhomogeneity were observed. Water angular motions in bassanite exhibit temperature-dependent diffusive orientational relaxation in a restricted cone of angles. The experiments were made possible by eliminating the vast amount of scattered light produced by the granulated powder samples using phase cycling methods. PMID:27385320

  4. Probing Intermolecular Interactions in Polycyclic Aromatic Hydrocarbons with 2D IR Spectroscopy

    Science.gov (United States)

    Krummel, Amber

    2014-03-01

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in the environment and impact geochemical processes that are critical to sustainable energy resources. For example, asphaltenes exist naturally in geologic formations and their aggregates heavily impact the petroleum economy. Unfortunately, the chemical dynamics that drive asphaltene nanoaggregation processes are still poorly understood. Solvent dynamics and intermolecular interactions such as π-stacking interactions play integral roles in asphaltene nanoaggregation. Linear and nonlinear vibrational spectroscopy including two-dimensional infrared spectroscopy (2DIR), are well suited to explore these fundamental interactions. Teasing apart the vibrational characteristics in PAHs that model asphaltenic compounds represents an important step towards utilizing 2D IR spectroscopy to understand the intermolecular interactions that are prevalent in asphaltene nanoaggregation. A solar dye, N,N'-Dioctyl-3,4,9,10-perylenedicarboximide, is used in this work to model aphaltenes. Carbonyl and ring vibrations are used to probe the nanoaggregates of the model compounds. However, the characteristics of these normal modes change as a function of the size of the conjugated ring system. Thus, in order to fully understand the nature of these normal modes, we include a systematic study of a series of quinones. Our investigation employs a combination of 2DIR spectroscopy and electronic structure calculations to explore vibrational coupling in quinones and PAHs. We compare the calculated vibrational characteristics to those extracted from 2DIR spectra. ATK acknowledges the Donors of the American Chemical Society Petroleum Research Fund for support of this research.

  5. Interrogating Fiber Formation Kinetics with Automated 2D-IR Spectroscopy

    Science.gov (United States)

    Strasfeld, David B.; Ling, Yun L.; Shim, Sang-Hee; Zanni, Martin T.

    A new method for collecting 2D-IR spectra that utilizes both a pump-probe beam geometry and a mid-IR pulse shaper is used to gain a fuller understanding of fiber formation in the human islet amyloid polypeptide (hIAPP). We extract structural kinetics in order to better understand aggregation in hIAPP, the protein component of the amyloid fibers found to inhibit insulin production in type II diabetes patients.

  6. Structural modifications of Tilia cordata wood during heat treatment investigated by FT-IR and 2D IR correlation spectroscopy

    Science.gov (United States)

    Popescu, Maria-Cristina; Froidevaux, Julien; Navi, Parviz; Popescu, Carmen-Mihaela

    2013-02-01

    It is known that heat treatment of wood combined with a low percent of relative humidity causes transformations in the chemical composition of it. The modifications and/or degradation of wood components occur by hydrolysis, oxidation, and decarboxylation reactions. The aim of this study was to give better insights on wood chemical modifications during wood heat treatment under low temperature at about 140 °C and 10% percentage of relative humidity, by infrared, principal component analysis and two dimensional infrared correlation spectroscopy. For this purpose, hardwood samples of lime (Tilia cordata) were investigated and analysed. The infrared spectra of treated samples were compared with the reference ones, the most important differences being observed in the "fingerprint" region. Due to the complexity of this region, which have contributions from all the wood constituents the chemical changes during hydro-thermal treatment were examined in detail using principal component analysis and 2D IR correlation spectroscopy. By hydro-thermal treatment of wood results the formation of acetic acid, which catalyse the hydrolysis reactions of hemicelluloses and amorphous cellulose. The cleavage of the β-O-4 linkages and splitting of the aliphatic methoxyl chains from the aromatic lignin ring was also observed. For the first treatment interval, a higher extent of carbohydrates degradation was observed, then an increase of the extent of the lignin degradation also took place.

  7. Earle K. Plyler Prize for Molecular Spectroscopy and Dynamics Lecture: 2D IR Spectroscopy of Peptide Conformation

    Science.gov (United States)

    Tokmakoff, Andrei

    2012-02-01

    Descriptions of protein and peptide conformation are colored by the methods we use to study them. Protein x-ray and NMR structures often lead to impressions of rigid or well-defined conformations, even though these are dynamic molecules. The conformational fluctuations and disorder of proteins and peptides is more difficult to quantify. This presentation will describe an approach toward characterizing and quantifying structural heterogeneity and disorder in peptides using 2D IR spectroscopy. Using amide I vibrational spectroscopy, isotope labeling strategies, and computational modeling based on molecular dynamics simulations and Markov state models allows us to characterize distinct peptide conformers and conformational variation. The examples illustrated include the beta-hairpin tripzip2 and elastin-like peptides.

  8. Observation of kinetic networks of hydrogen-bond exchange using 2D IR echo spectroscopy

    Science.gov (United States)

    Kim, Yung Sam; Hochstrasser, Robin M.

    The ultrafast H-bond motion in acetonitrile/methanol and of methanol and water around a dicarbonyl (piperidone) dominates the mechanism of vibrational coherence transfer in linear and 2D IR echo spectra. Multiple state coherence transfer and energy transfer are seen at and between the two carbonyl groups of the piperidone in both water and methanol.

  9. Study on antibacterial alginate-stabilized copper nanoparticles by FT-IR and 2D-IR correlation spectroscopy

    Directory of Open Access Journals (Sweden)

    Díaz-Visurraga J

    2012-07-01

    Full Text Available Judith Díaz-Visurraga,1,2 Carla Daza,2 Claudio Pozo,2 Abraham Becerra,2 Carlos von Plessing,1,2 Apolinaria García31Department of Pharmacy, Faculty of Pharmacy, University of Concepcion; 2Research Center of Advanced Polymers (CIPA, CONICYT REGIONAL/CIPA R08C1002; 3Department of Microbiology, Faculty of Biological Sciences, University of Concepcion, Concepción, ChileBackground: The objective of this study was to clarify the intermolecular interaction between antibacterial copper nanoparticles (Cu NPs and sodium alginate (NaAlg by Fourier transform infrared spectroscopy (FT-IR and to process the spectra applying two-dimensional infrared (2D-IR correlation analysis. To our knowledge, the addition of NaAlg as a stabilizer of copper nanoparticles has not been previously reported. It is expected that the obtained results will provide valuable additional information on: (1 the influence of reducing agent ratio on the formation of copper nanoparticles in order to design functional nanomaterials with increased antibacterial activity, and (2 structural changes related to the incorporation of Cu NPs into the polymer matrix.Methods: Cu NPs were prepared by microwave heating using ascorbic acid as reducing agent and NaAlg as stabilizing agent. The characterization of synthesized Cu NPs by ultraviolet visible spectroscopy, transmission electron microscopy (TEM, electron diffraction analysis, X-ray diffraction (XRD, and semiquantitative analysis of the weight percentage composition indicated that the average particle sizes of Cu NPs are about 3–10 nm, they are spherical in shape, and consist of zerovalent Cu and Cu2O. Also, crystallite size and relative particle size of stabilized Cu NPs were calculated by XRD using Scherrer’s formula and FT from the X-ray diffraction data. Thermogravimetric analysis, differential thermal analysis, differential scanning calorimetry (DSC, FT-IR, second-derivative spectra, and 2D-IR correlation analysis were applied to

  10. Rapid identification of Pterocarpus santalinus and Dalbergia louvelii by FTIR and 2D correlation IR spectroscopy

    Science.gov (United States)

    Zhang, Fang-Da; Xu, Chang-Hua; Li, Ming-Yu; Huang, An-Min; Sun, Su-Qin

    2014-07-01

    Since Pterocarpus santalinus and Dalbergia louvelii, which are of precious Rosewood, are very similar in their appearance and anatomy characteristics, cheaper Hongmu D. louvelii is often illegally used to impersonate valuable P. santalinus, especially in Chinese furniture manufacture. In order to develop a rapid and effective method for easy confused wood furniture differentiation, we applied tri-step identification method, i.e., conventional infrared spectroscopy (FT-IR), second derivative infrared (SD-IR) spectroscopy and two-dimensional correlation infrared (2DCOS-IR) spectroscopy to investigate P. santalinus and D. louvelii furniture. According to FT-IR and SD-IR spectra, it has been found two unconditional stable difference at 848 cm-1 and 700 cm-1 and relative stable differences at 1735 cm-1, 1623 cm-1, 1614 cm-1, 1602 cm-1, 1509 cm-1, 1456 cm-1, 1200 cm-1, 1158 cm-1, 1055 cm-1, 1034 cm-1 and 895 cm-1 between D. louvelii and P. santalinus IR spectra. The stable discrepancy indicates that the category of extractives is different between the two species. Besides, the relative stable differences imply that the content of holocellulose in P. santalinus is more than that of D. louvelii, whereas the quantity of extractives in D. louvelii is higher. Furthermore, evident differences have been observed in their 2DCOS-IR spectra of 1550-1415 cm-1 and 1325-1030 cm-1. P. santalinus has two strong auto-peaks at 1459 cm-1 and 1467 cm-1, three mid-strong auto-peaks at 1518 cm-1, 1089 cm-1 and 1100 cm-1 and five weak auto-peaks at 1432 cm-1, 1437 cm-1, 1046 cm-1, 1056 cm-1 and 1307 cm-1 while D. louvelii has four strong auto-peaks at 1465 cm-1, 1523 cm-1, 1084 cm-1 and 1100 cm-1, four mid-strong auto-peaks at 1430 cm-1, 1499 cm-1, 1505 cm-1 and 1056 cm-1 and two auto-peaks at 1540 cm-1 and 1284 cm-1. This study has proved that FT-IR integrated with 2DCOS-IR could be applicable for precious wood furniture authentication in a direct, rapid and holistic manner.

  11. Characterization by Fourier transform infrared spectroscopy (FT-IR) and 2D IR correlation spectroscopy of a carbosilane dendrimer with peripheral ammonium groups

    Energy Technology Data Exchange (ETDEWEB)

    Popescu, Maria-Cristina, E-mail: cpopescu@icmpp.ro [' Petru Poni' Institute of Macromolecular Chemistry (Romania); Gomez, Rafael; Mata, Fco Javier de la; Rasines, Beatriz [Universidad de Alcala, Departamento de Quimica Inorganica (Spain); Simionescu, Bogdan C. [' Petru Poni' Institute of Macromolecular Chemistry (Romania)

    2013-06-15

    Fourier transform infrared spectroscopy and 2D correlation spectroscopy were used to study the microstructural changes occurring on heating of a new carbosilane dendrimer with peripheral ammonium groups. Temperature-dependent spectral variations in the 3,010-2,710, 1,530-1,170, and 1,170-625 cm{sup -1} regions were monitored during the heating process. The dependence, on temperature, of integral absorptions and position of spectral bands was established and the spectral modifications associated with molecular conformation rearrangements, allowing molecular shape changes, were found. Before 180 Degree-Sign C, the studied carbosilane dendrimer proved to be stable, while at higher temperatures it oxidizes and Si-O groups appear. 2D IR correlation spectroscopy gives new information about the effect of temperature on the structure and dynamics of the system. Synchronous and asynchronous spectra indicate that, at low temperature, conformational changes of CH{sub 3} and CH{sub 3}-N{sup +} groups take place first. With increasing temperature, the intensity variation of the CH{sub 2}, C-N, Si-C and C-C groups from the dendritic core is faster than that of the terminal units. This indicates that, with increasing temperature, the segments of the dendritic core obtain enough energy to change their conformation more easily as compared to the terminal units, due to their internal flexibility.

  12. Electrostatic interactions in phospholipid membranes revealed by coherent 2D IR spectroscopy

    Science.gov (United States)

    Volkov, V. V.; Chelli, R.; Zhuang, W.; Nuti, F.; Takaoka, Y.; Papini, A. M.; Mukamel, S.; Righini, R.

    2007-01-01

    The inter- and intramolecular interactions of the carbonyl moieties at the polar interface of a phospholipid membrane are probed by using nonlinear femtosecond infrared spectroscopy. Two-dimensional IR correlation spectra separate homogeneous and inhomogeneous broadenings and show a distinct cross-peak pattern controlled by electrostatic interactions. The inter- and intramolecular electrostatic interactions determine the inhomogeneous character of the optical response. Using molecular dynamics simulation and the nonlinear exciton equations approach, we extract from the spectra short-range structural correlations between carbonyls at the interface. PMID:17881567

  13. Ultrafast slaving dynamics at the protein-water interface studied with 2D-IR spectroscopy

    Directory of Open Access Journals (Sweden)

    Kubarych K. J.

    2013-03-01

    Full Text Available The dynamics of hen egg white lysozyme in D2O/glycerol mixtures is studied using two-dimensional infrared spectroscopy. The hydration dynamics and the protein dynamics are studied simultaneously through vibrational probes attached to the protein surface.

  14. Azide-water intermolecular coupling measured by 2-color 2D IR spectroscopy

    Directory of Open Access Journals (Sweden)

    Perakis F.

    2013-03-01

    Full Text Available We present 2-color two-dimensional infrared spectroscopy of intermolecular coupling between azide ions and their solvation shell water molecules. The cross-peak between azide asymmetric stretch vibration and the OD-stretch vibration is a result of low- probability uphill population transfer. Narrow bleach/excited state absorption peak shows selectivity to solvation shell water molecules only and the characteristics of the cross-peak suggest that the solvation shell hydrogen bond potential has similar anharmonic properties as the hydrogen bond in ice Ih. Population and depopulation of the excited state of the OD-stretch vibration happen on 150 fs and 1.7 ps timescales, respectively, with early manifesting heating effects that limit the selectivity to population times up to 1 ps.

  15. 2D-IR spectroscopy of hydrogen-bond-mediated vibrational excitation transfer.

    Science.gov (United States)

    Chuntonov, Lev

    2016-05-18

    Vibrational excitation transfer along the hydrogen-bond-mediated pathways in the complex of methyl acetate (MA) and 4-cyanophenol (4CP) was studied by dual-frequency femtosecond two-dimensional infrared spectroscopy. We excited the energy-donating ester carbonyl stretching vibrational mode and followed the transfer to the energy-accepting benzene ring and cyano stretching vibrations. The complexes with no, one, and two hydrogen-bonded 4CP molecules were studied. Vibrational relaxation of the carbonyl mode is more efficient in both hydrogen-bonded complexes as compared with free MA molecules. The inter-molecular transport in a hydrogen-bonded complex involving a single 4CP molecule is slower than that in a complex with two 4CP molecules. In the former, vibrational relaxation leads to local heating, as shown by the spectroscopy of the carbonyl mode, whereas the local heating is suppressed in the latter because the excitation redistribution is more efficient. At early times, the transfer to the benzene ring is governed by its direct coupling with the energy-donating carbonyl mode, whereas at later times intermediate states are involved. The transfer to a more distant site of the cyano group in 4CP involves intermediate states at all times, since no direct coupling between the energy-donating and accepting modes was observed. We anticipate that our findings will be of importance for spectroscopic studies of bio-molecular structures and dynamics, and inter- and intra-molecular signaling pathways, and for developing molecular networking applications. PMID:27145861

  16. Communication: Nanosecond folding dynamics of an alpha helix: Time-dependent 2D-IR cross peaks observed using polarization-sensitive dispersed pump-probe spectroscopy

    NARCIS (Netherlands)

    M.R. Panman; C.N. van Dijk; H. Meuzelaar; S. Woutersen

    2015-01-01

    We present a simple method to measure the dynamics of cross peaks in time-resolved two-dimensional vibrational spectroscopy. By combining suitably weighted dispersed pump-probe spectra, we eliminate the diagonal contribution to the 2D-IR response, so that the dispersed pump-probe signal contains the

  17. 2D IR Spectroscopy of Histidine: Probing Side-Chain Structure and Dynamics via Backbone Amide Vibrations

    OpenAIRE

    Ghosh, Ayanjeet; Tucker, Matthew J.; Gai, Feng

    2014-01-01

    It is well known that histidine is involved in many biological functions due to the structural versatility of its side chain. However, probing the conformational transitions of histidine in proteins, especially those occurring on an ultrafast time scale, is difficult. Herein we show, using a histidine dipeptide as a model, that it is possible to probe the tautomer and protonation status of a histidine residue by measuring the two-dimensional infrared (2D IR) spectrum of its amide I vibrationa...

  18. Two Keggin-type heteropolytungstates with transition metal as a central atom: Crystal structure and magnetic study with 2D-IR correlation spectroscopy

    International Nuclear Information System (INIS)

    Two Keggin-type heteropolytungstates, [Co(phen)3]3[CoW12O40]·9H2O 1 (phen=1,10-phenanthroline) and [Fe(phen)3]2[FeW12O40]·H3O·H2O 2, have been synthesized via the hydrothermal technique and characterized by single crystal X-ray diffraction analyses, IR, XPS, TG analysis, UV–DRS, XRD, thermal-dependent and magnetic-dependent 2D-COS IR (two-dimensional infrared correlation spectroscopy). Crystal structure analysis reveals that the polyanions in compound 1 are linked into 3D supramolecule through hydrogen bonding interactions between lattice water molecules and terminal oxygen atoms of polyanion units, and [Co(phen)3]2+ cations distributed in the polyanion framework with many hydrogen bonding interactions. The XPS spectra indicate that all the Co atoms in 1 are +2 oxidation state, the Fe atoms in 2 existing with +2 and +3 mixed oxidation states. - Graphical abstract: The magnetic-dependent synchronous 2D correlation IR spectra of 1 (a), 2 (b) over 0–50 mT in the range of 600–1000 cm−1, the obvious response indicate two Keggin polyanions skeleton susceptible to applied magnetic field. - Highlights: • Two Keggin-type heteropolytungstates with transition metal as a central atom has been obtained. • Compound 1 forms into 3D supramolecular architecture through hydrogen bonding between water molecules and polyanions. • Magnetic-dependent 2D-IR correlation spectroscopy was introduced to discuss the magnetism of polyoxometalate

  19. 2D IR spectroscopy reveals the role of water in the binding of channel-blocking drugs to the influenza M2 channel

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Ayanjeet, E-mail: ayanjeet@sas.upenn.edu, E-mail: gai@sas.upenn.edu; Gai, Feng, E-mail: ayanjeet@sas.upenn.edu, E-mail: gai@sas.upenn.edu; Hochstrasser, Robin M. [Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States); Wang, Jun; DeGrado, William F. [Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California 94143 (United States); Moroz, Yurii S.; Korendovych, Ivan V. [Department of Chemistry, Syracuse University, Syracuse, New York 13244 (United States); Zanni, Martin [Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706 (United States)

    2014-06-21

    Water is an integral part of the homotetrameric M2 proton channel of the influenza A virus, which not only assists proton conduction but could also play an important role in stabilizing channel-blocking drugs. Herein, we employ two dimensional infrared (2D IR) spectroscopy and site-specific IR probes, i.e., the amide I bands arising from isotopically labeled Ala30 and Gly34 residues, to probe how binding of either rimantadine or 7,7-spiran amine affects the water dynamics inside the M2 channel. Our results show, at neutral pH where the channel is non-conducting, that drug binding leads to a significant increase in the mobility of the channel water. A similar trend is also observed at pH 5.0 although the difference becomes smaller. Taken together, these results indicate that the channel water facilitates drug binding by increasing its entropy. Furthermore, the 2D IR spectral signatures obtained for both probes under different conditions collectively support a binding mechanism whereby amantadine-like drugs dock in the channel with their ammonium moiety pointing toward the histidine residues and interacting with a nearby water cluster, as predicted by molecular dynamics simulations. We believe these findings have important implications for designing new anti-influenza drugs.

  20. Solvation of fluoro-acetonitrile in water by 2D-IR spectroscopy: A combined experimental-computational study

    Energy Technology Data Exchange (ETDEWEB)

    Cazade, Pierre-André; Das, Akshaya K. [Department of Chemistry, University of Basel, Klingelbergstrasse 80, 4056 Basel (Switzerland); Tran, Halina; Kläsi, Felix; Hamm, Peter [Department of Chemistry, University of Zurich, Winterthurerstr. 190, 8057 Zurich (Switzerland); Bereau, Tristan [Max-Planck-Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz (Germany); Meuwly, Markus, E-mail: m.meuwly@unibas.ch [Department of Chemistry, University of Basel, Klingelbergstrasse 80, 4056 Basel (Switzerland); Department of Chemistry, Brown University, Providence, Rhode Island 02912 (United States)

    2015-06-07

    The solvent dynamics around fluorinated acetonitrile is characterized by 2-dimensional infrared spectroscopy and atomistic simulations. The lineshape of the linear infrared spectrum is better captured by semiempirical (density functional tight binding) mixed quantum mechanical/molecular mechanics simulations, whereas force field simulations with multipolar interactions yield lineshapes that are significantly too narrow. For the solvent dynamics, a relatively slow time scale of 2 ps is found from the experiments and supported by the mixed quantum mechanical/molecular mechanics simulations. With multipolar force fields fitted to the available thermodynamical data, the time scale is considerably faster—on the 0.5 ps time scale. The simulations provide evidence for a well established CF–HOH hydrogen bond (population of 25%) which is found from the radial distribution function g(r) from both, force field and quantum mechanics/molecular mechanics simulations.

  1. Interplay of Ion-Water and Water-Water Interactions within the Hydration Shells of Nitrate and Carbonate Directly Probed with 2D IR Spectroscopy.

    Science.gov (United States)

    Fournier, Joseph A; Carpenter, William; De Marco, Luigi; Tokmakoff, Andrei

    2016-08-01

    The long-range influence of ions in solution on the water hydrogen-bond (H-bond) network remains a topic of vigorous debate. Recent spectroscopic and theoretical studies have, for the most part, reached the consensus that weakly coordinating ions only affect water molecules in the first hydration shell. Here, we apply ultrafast broadband two-dimensional infrared (2D IR) spectroscopy to aqueous nitrate and carbonate in neat H2O to study the solvation structure and dynamics of ions on opposite ends of the Hofmeister series. By exciting both the water OH stretches and ion stretches and probing the associated cross-peaks between them, we are afforded a comprehensive view into the complex nature of ion hydration. We show in aqueous nitrate that weak ion-water H-bonding leads to water-water interactions in the ion solvation shells dominating the dynamics. In contrast, the carbonate CO stretches show significant mixing with the water OH stretches due to strong ion-water H-bonding such that the water and ion modes are intimately correlated. Further, the excitonic nature of vibrations in neat H2O, which spans multiple water molecules, is an important factor in describing ion hydration. We attribute these complex dynamics to the likely presence of intermediate-range effects influenced by waters beyond the first solvation shell. PMID:27404015

  2. Ultrafast vibrational spectroscopy (2D-IR) of CO2 in ionic liquids: Carbon capture from carbon dioxide's point of view

    Science.gov (United States)

    Brinzer, Thomas; Berquist, Eric J.; Ren, Zhe; Dutta, Samrat; Johnson, Clinton A.; Krisher, Cullen S.; Lambrecht, Daniel S.; Garrett-Roe, Sean

    2015-06-01

    The CO2ν3 asymmetric stretching mode is established as a vibrational chromophore for ultrafast two-dimensional infrared (2D-IR) spectroscopic studies of local structure and dynamics in ionic liquids, which are of interest for carbon capture applications. CO2 is dissolved in a series of 1-butyl-3-methylimidazolium-based ionic liquids ([C4C1im][X], where [X]- is the anion from the series hexafluorophosphate (PF 6- ), tetrafluoroborate (BF 4- ), bis-(trifluoromethyl)sulfonylimide (Tf2N-), triflate (TfO-), trifluoroacetate (TFA-), dicyanamide (DCA-), and thiocyanate (SCN-)). In the ionic liquids studied, the ν3 center frequency is sensitive to the local solvation environment and reports on the timescales for local structural relaxation. Density functional theory calculations predict charge transfer from the anion to the CO2 and from CO2 to the cation. The charge transfer drives geometrical distortion of CO2, which in turn changes the ν3 frequency. The observed structural relaxation timescales vary by up to an order of magnitude between ionic liquids. Shoulders in the 2D-IR spectra arise from anharmonic coupling of the ν2 and ν3 normal modes of CO2. Thermal fluctuations in the ν2 population stochastically modulate the ν3 frequency and generate dynamic cross-peaks. These timescales are attributed to the breakup of ion cages that create a well-defined local environment for CO2. The results suggest that the picosecond dynamics of CO2 are gated by local diffusion of anions and cations.

  3. Ultrafast vibrational spectroscopy (2D-IR) of CO{sub 2} in ionic liquids: Carbon capture from carbon dioxide’s point of view

    Energy Technology Data Exchange (ETDEWEB)

    Brinzer, Thomas; Berquist, Eric J.; Ren, Zhe; Dutta, Samrat; Johnson, Clinton A.; Krisher, Cullen S.; Lambrecht, Daniel S.; Garrett-Roe, Sean, E-mail: sgr@pitt.edu [Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, Pennsylvania 15260 (United States)

    2015-06-07

    The CO{sub 2}ν{sub 3} asymmetric stretching mode is established as a vibrational chromophore for ultrafast two-dimensional infrared (2D-IR) spectroscopic studies of local structure and dynamics in ionic liquids, which are of interest for carbon capture applications. CO{sub 2} is dissolved in a series of 1-butyl-3-methylimidazolium-based ionic liquids ([C{sub 4}C{sub 1}im][X], where [X]{sup −} is the anion from the series hexafluorophosphate (PF{sub 6}{sup −}), tetrafluoroborate (BF{sub 4}{sup −}), bis-(trifluoromethyl)sulfonylimide (Tf{sub 2}N{sup −}), triflate (TfO{sup −}), trifluoroacetate (TFA{sup −}), dicyanamide (DCA{sup −}), and thiocyanate (SCN{sup −})). In the ionic liquids studied, the ν{sub 3} center frequency is sensitive to the local solvation environment and reports on the timescales for local structural relaxation. Density functional theory calculations predict charge transfer from the anion to the CO{sub 2} and from CO{sub 2} to the cation. The charge transfer drives geometrical distortion of CO{sub 2}, which in turn changes the ν{sub 3} frequency. The observed structural relaxation timescales vary by up to an order of magnitude between ionic liquids. Shoulders in the 2D-IR spectra arise from anharmonic coupling of the ν{sub 2} and ν{sub 3} normal modes of CO{sub 2}. Thermal fluctuations in the ν{sub 2} population stochastically modulate the ν{sub 3} frequency and generate dynamic cross-peaks. These timescales are attributed to the breakup of ion cages that create a well-defined local environment for CO{sub 2}. The results suggest that the picosecond dynamics of CO{sub 2} are gated by local diffusion of anions and cations.

  4. Ultrafast vibrational spectroscopy (2D-IR) of CO2 in ionic liquids: Carbon capture from carbon dioxide’s point of view

    International Nuclear Information System (INIS)

    The CO2ν3 asymmetric stretching mode is established as a vibrational chromophore for ultrafast two-dimensional infrared (2D-IR) spectroscopic studies of local structure and dynamics in ionic liquids, which are of interest for carbon capture applications. CO2 is dissolved in a series of 1-butyl-3-methylimidazolium-based ionic liquids ([C4C1im][X], where [X]− is the anion from the series hexafluorophosphate (PF6−), tetrafluoroborate (BF4−), bis-(trifluoromethyl)sulfonylimide (Tf2N−), triflate (TfO−), trifluoroacetate (TFA−), dicyanamide (DCA−), and thiocyanate (SCN−)). In the ionic liquids studied, the ν3 center frequency is sensitive to the local solvation environment and reports on the timescales for local structural relaxation. Density functional theory calculations predict charge transfer from the anion to the CO2 and from CO2 to the cation. The charge transfer drives geometrical distortion of CO2, which in turn changes the ν3 frequency. The observed structural relaxation timescales vary by up to an order of magnitude between ionic liquids. Shoulders in the 2D-IR spectra arise from anharmonic coupling of the ν2 and ν3 normal modes of CO2. Thermal fluctuations in the ν2 population stochastically modulate the ν3 frequency and generate dynamic cross-peaks. These timescales are attributed to the breakup of ion cages that create a well-defined local environment for CO2. The results suggest that the picosecond dynamics of CO2 are gated by local diffusion of anions and cations

  5. Study on the Processing of Leech by FTIR and 2D-IR Correlation Spectroscopy%应用红外光谱技术研究中药水蛭的炮制过程

    Institute of Scientific and Technical Information of China (English)

    李冰宁; 武彦文; 欧阳杰; 孙素琴; 陈舜琮

    2011-01-01

    考察水蚝炮制前后化学成分产生的变化,文章采用红外光谱(FTlR)二维相关红外谱图(2D-IR)对中药水蛭鲜品和制品进行了研究.结果表明:水蛭具有明显的酰胺Ⅰ和Ⅱ带蛋白质特征峰,其中鲜品的酰胺Ⅱ带吸收峰在1543 cm-1,而生品和炮制品的向低频位移至1 535cm-1;采用热微扰模拟水蛭炮制过程并分析水蛭的2D-IR,结果显示水蛭鲜品中的酰胺Ⅰ带与酰胺Ⅱ带的自动峰的强度比炮制品的更为显著.说明水蛭在炮制过程中蛋白质的空间构象破损、氢键断裂,导致变性失活,部分脂肪酸和甾醇类组分在炮制中发生氧化分解.%The chemical differences of traditional Chinese medicine leech before and after processing were analyzed by FTIR and two-dimensional correlation infrared (2D-IR) spectroscopy. The result showed that the leech was high in protein, with characteristic peaks of amide Ⅰ, Ⅱ bands. Comparing the IR spectra of samples, the primary difference was that the characteristic peak of fresh leech was at 1 543 cm-1, while that of crude and processed leech was at 1 535 cm-1. A 2D-IR spectrum with heating perturbation was used to track the processing dynamics of leech. In the 2D-IR correlation spectra, fresh leech exhibited stronger automatic peaks of the amide Ⅰ and Ⅱ hands than that of processed leech, which indicates that the protein components of the fresh leech were more sensitive to heat perturhation than the processed one. Moreover, the result of FTIR and 2D-IR correlation spectra validated that the 3-dimensional structure of protein was damaged and hydrogen bonds were broken after processing, which resulted in the inactivation of protein. The fatty acids and cholesterol components of leech were also oxidized in this process.

  6. Identification of Serine Conformers by Matrix-Isolation IR Spectroscopy Aided by Near-Infrared Laser-Induced Conformational Change, 2D Correlation Analysis, and Quantum Mechanical Anharmonic Computations.

    Science.gov (United States)

    Najbauer, Eszter E; Bazsó, Gábor; Apóstolo, Rui; Fausto, Rui; Biczysko, Malgorzata; Barone, Vincenzo; Tarczay, György

    2015-08-20

    The conformers of α-serine were investigated by matrix-isolation IR spectroscopy combined with NIR laser irradiation. This method, aided by 2D correlation analysis, enabled unambiguously grouping the spectral lines to individual conformers. On the basis of comparison of at least nine experimentally observed vibrational transitions of each conformer with empirically scaled (SQM) and anharmonic (GVPT2) computed IR spectra, six conformers were identified. In addition, the presence of at least one more conformer in Ar matrix was proved, and a short-lived conformer with a half-life of (3.7 ± 0.5) × 10(3) s in N2 matrix was generated by NIR irradiation. The analysis of the NIR laser-induced conversions revealed that the excitation of the stretching overtone of both the side chain and the carboxylic OH groups can effectively promote conformational changes, but remarkably different paths were observed for the two kinds of excitations. PMID:26201050

  7. Internal Photoemission Spectroscopy of 2-D Materials

    Science.gov (United States)

    Nguyen, Nhan; Li, Mingda; Vishwanath, Suresh; Yan, Rusen; Xiao, Shudong; Xing, Huili; Cheng, Guangjun; Hight Walker, Angela; Zhang, Qin

    Recent research has shown the great benefits of using 2-D materials in the tunnel field-effect transistor (TFET), which is considered a promising candidate for the beyond-CMOS technology. The on-state current of TFET can be enhanced by engineering the band alignment of different 2D-2D or 2D-3D heterostructures. Here we present the internal photoemission spectroscopy (IPE) approach to determine the band alignments of various 2-D materials, in particular SnSe2 and WSe2, which have been proposed for new TFET designs. The metal-oxide-2-D semiconductor test structures are fabricated and characterized by IPE, where the band offsets from the 2-D semiconductor to the oxide conduction band minimum are determined by the threshold of the cube root of IPE yields as a function of photon energy. In particular, we find that SnSe2 has a larger electron affinity than most semiconductors and can be combined with other semiconductors to form near broken-gap heterojunctions with low barrier heights which can produce a higher on-state current. The details of data analysis of IPE and the results from Raman spectroscopy and spectroscopic ellipsometry measurements will also be presented and discussed.

  8. Localised IR spectroscopy of hemoglobin

    CERN Document Server

    Yarrow, Fiona

    2010-01-01

    IR absorption spectroscopy of hemoglobin was performed using an IR optical parametric oscillator laser and a commercial atomic force microscope in a novel experimental arrangement based on the use of a bottom-up excitation alignment. This experimental approach enables detection of protein samples with a resolution that is much higher than that of standard IR spectroscopy. Presented here are AFM based IR absorption spectra of micron sized hemoglobin features

  9. Photocurrent spectroscopy of 2D materials

    Science.gov (United States)

    Cobden, David

    Confocal photocurrent measurements provide a powerful means of studying many aspects of the optoelectronic and electrical properties of a 2D device or material. At a diffraction-limited point they can provide a detailed absorption spectrum, and they can probe local symmetry, ultrafast relaxation rates and processes, electron-electron interaction strengths, and transport coefficients. We illustrate this with several examples, once being the photo-Nernst effect. In gapless 2D materials, such as graphene, in a perpendicular magnetic field a photocurrent antisymmetric in the field is generated near to the free edges, with opposite sign at opposite edges. Its origin is the transverse thermoelectric current associated with the laser-induced electron temperature gradient. This effect provides an unambiguous demonstration of the Shockley-Ramo nature of long-range photocurrent generation in gapless materials. It also provides a means of investigating quasiparticle properties. For example, in the case of graphene on hBN, it can be used to probe the Lifshitz transition that occurs due to the minibands formed by the Moire superlattice. We also observe and discuss photocurrent generated in other semimetallic (WTe2) and semiconducting (WSe2) monolayers. Work supported by DoE BES and NSF EFRI grants.

  10. 不同产地茯苓皮药材红外光谱的识别%Analysis and Identification of Poria Cocos Peels Harvested form Different Producing Areas by FTIR and 2D-IR Correlation Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    马芳; 张方; 汤进; 陈平; 陈建波; 周群; 孙素琴

    2014-01-01

    Different geographical regions of traditional Chinese medicine (TCM ) ,its chemical composition is different ,the accu-mulation of drug and medicinal properties is different .The accurate identification and analysis of different production area of me-dicinal herbs is critical for the quality control and pharmacological research of TCM .In this paper ,a tri-step infrared spectrosco-py (Fourier transform infrared spectroscopy (FTIR) combined with second derivative spectra and two-dimensional correlation in-frared spectroscopy (2D-COS) were employed to identify and analyze the main components of Hubei(HB) ,Anhui(AH) ,Yun-nan(YN) genuine Poria Cocos peels .The emergence of several characteristic absorption peaks of carbohydrates including 1 149 , 1 079 1 036 cm -1 ,peaks around 1 619 ,1 315 ,780 cm -1 belonged to calcium oxalate suggested that HB and AH Poria Cocos peels contained calcium oxalate ,but peaks around 797 ,779 ,537 ,470 cm -1 belonged to kaoline suggested that YN Poria Cocos peels contained kaoline .Their carbohydrates were different by comparing the second derivative infrared spectra in the range of 1 640~450 cm -1 and Yongping come from YN contains both calcium oxalate and kaoline .Furthermore ,the above differences were visually validated by two-dimensional correlation spectroscopy (2D-COS) .It was demonstrated that the Tri-step infrared spectroscopy were successfully applied to fast analyze and identify Poria Cocos peels from different geographical regions and sub-sequently would be applicable to explain the relevance of geographical regions and medicinal properties for the TCM .%采用红外光谱、二阶导数光谱和二维相关红外光谱对大别山地区和云南省两大道地主产区的茯苓皮进行鉴别分析。结果表明,不同产地茯苓皮的红外光谱都有1149,1079和1036 cm -1等表征糖类成分的特征吸收峰,其中大别山产区(湖北省、安徽省)的茯苓皮中1619,1315和780 cm -1等表征草酸钙

  11. Double resonance rotational spectroscopy of CH2D+

    Science.gov (United States)

    Töpfer, Matthias; Jusko, Pavol; Schlemmer, Stephan; Asvany, Oskar

    2016-09-01

    Context. Deuterated forms of CH are thought to be responsible for deuterium enrichment in lukewarm astronomical environments. There is no unambiguous detection of CH2D+ in space to date. Aims: Four submillimetre rotational lines of CH2D+ are documented in the literature. Our aim is to present a complete dataset of highly resolved rotational lines, including millimetre (mm) lines needed for a potential detection. Methods: We used a low-temperature ion trap and applied a novel IR-mm-wave double resonance method to measure the rotational lines of CH2D+. Results: We measured 21 low-lying (J ≤ 4) rotational transitions of CH2D+ between 23 GHz and 1.1 THz with accuracies close to 2 ppb.

  12. Picosecond dynamics of a membrane protein revealed by 2D IR

    Science.gov (United States)

    Mukherjee, Prabuddha; Kass, Itamar; Arkin, Isaiah T.; Zanni, Martin T.

    2006-03-01

    Fast protein dynamics can be missed with techniques that have relatively slow observation times. Using 2D IR spectroscopy and isotope labeling, we have probed the rapid, picosecond dynamics of a membrane protein in its native environment. By measuring the homogeneous and inhomogeneous IR linewidths of 11 amide I modes (backbone carbonyl stretch), we have captured the structural distributions and dynamics of the CD3 protein along its transmembrane segment that are lost with slower time-scale techniques. We find that the homogeneous lifetimes and population relaxation times are the same for almost all of the residues. In contrast, the inhomogeneous linewidths vary significantly with the largest inhomogeneous distribution occurring for residues near the N terminus and the narrowest near the center. This behavior is highly consistent with a recently reported experimental model of the protein and water accessibility as observed by molecular dynamics simulations. The data support the proposed CD3 peptide structure, and the simulations point to the structural disorder of water and lipid head-groups as the main source of inhomogeneous broadening. Taken together, this rigorous analysis of the vibrational dynamics of a membrane peptide provides experimental insight into a time regime of motions that has so far been largely unexplored. spectroscopy | ultrafast | vibrational

  13. Determining Transition State Geometries in Liquids Using 2D-IR

    Energy Technology Data Exchange (ETDEWEB)

    Harris, Charles; Cahoon, James F.; Sawyer, Karma R.; Schlegel, Jacob P.; Harris, Charles B.

    2007-12-11

    Many properties of chemical reactions are determined by the transition state connecting reactant and product, yet it is difficult to directly obtain any information about these short-lived structures in liquids. We show that two-dimensional infrared (2D-IR) spectroscopy can provide direct information about transition states by tracking the transformation of vibrational modes as a molecule crossed a transition state. We successfully monitored a simple chemical reaction, the fluxional rearrangement of Fe(CO)5, in which the exchange of axial and equatorial CO ligands causes an exchange of vibrational energy between the normal modes of the molecule. This energy transfer provides direct evidence regarding the time scale, transition state, and mechanism of the reaction.

  14. Isolated Gramicidin Peptides Probed by IR Spectroscopy

    NARCIS (Netherlands)

    Rijs, A. M.; Kabelac, M.; Abo-Riziq, A.; Hobza, P.; de Vries, M. S.

    2011-01-01

    We report double-resonant IR/UV ion-dip spectroscopy of neutral gramicidin peptides in the gas phase. The IR spectra of gramicidin A and C, recorded in both the 1000 cm(-1) to 1800 cm(-1) and the 2700 to 3750 cm(-1) region, allow structural analysis. By studying this broad IR range, various local in

  15. Biochemical applications of FT-IR spectroscopy

    NARCIS (Netherlands)

    Pistorius, A.M.A.

    1996-01-01

    This thesis describes the use of (FT-)IR spectroscopy in general biochemical research. In chapter 3, IR spectroscopy is used in the quantitation of residual detergent after reconstitution of an integral membrane protein in a pre-defined lipid matrix. This chapter discusses the choice of the vibratio

  16. IR nanoscale spectroscopy and imaging

    Science.gov (United States)

    Kennedy, Eamonn; Yarrow, Fiona; Rice, James H.

    2011-10-01

    Sub diffraction limited infrared absorption imaging was applied to hemoglobin by coupling IR optics with an atomic force microscope. Comparisons between the AFM topography and IR absorption images of micron sized hemoglobin features are presented, along with nanoscale IR spectroscopic analysis of the metalloprotein.

  17. Quantum process tomography by 2D fluorescence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Pachón, Leonardo A. [Grupo de Física Atómica y Molecular, Instituto de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín (Colombia); Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138 (United States); Marcus, Andrew H. [Department of Chemistry and Biochemistry, Oregon Center for Optics, Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403 (United States); Aspuru-Guzik, Alán [Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138 (United States)

    2015-06-07

    Reconstruction of the dynamics (quantum process tomography) of the single-exciton manifold in energy transfer systems is proposed here on the basis of two-dimensional fluorescence spectroscopy (2D-FS) with phase-modulation. The quantum-process-tomography protocol introduced here benefits from, e.g., the sensitivity enhancement ascribed to 2D-FS. Although the isotropically averaged spectroscopic signals depend on the quantum yield parameter Γ of the doubly excited-exciton manifold, it is shown that the reconstruction of the dynamics is insensitive to this parameter. Applications to foundational and applied problems, as well as further extensions, are discussed.

  18. Ultrafast 2D NMR: An Emerging Tool in Analytical Spectroscopy

    Science.gov (United States)

    Giraudeau, Patrick; Frydman, Lucio

    2014-06-01

    Two-dimensional nuclear magnetic resonance (2D NMR) spectroscopy is widely used in chemical and biochemical analyses. Multidimensional NMR is also witnessing increased use in quantitative and metabolic screening applications. Conventional 2D NMR experiments, however, are affected by inherently long acquisition durations, arising from their need to sample the frequencies involved along their indirect domains in an incremented, scan-by-scan nature. A decade ago, a so-called ultrafast (UF) approach was proposed, capable of delivering arbitrary 2D NMR spectra involving any kind of homo- or heteronuclear correlation, in a single scan. During the intervening years, the performance of this subsecond 2D NMR methodology has been greatly improved, and UF 2D NMR is rapidly becoming a powerful analytical tool experiencing an expanded scope of applications. This review summarizes the principles and main developments that have contributed to the success of this approach and focuses on applications that have been recently demonstrated in various areas of analytical chemistry—from the real-time monitoring of chemical and biochemical processes, to extensions in hyphenated techniques and in quantitative applications.

  19. Volatility-dependent 2D IR correlation analysis of traditional Chinese medicine ‘Red Flower Oil’ preparation from different manufacturers

    Science.gov (United States)

    Wu, Yan-Wen; Sun, Su-Qin; Zhou, Qun; Tao, Jia-Xun; Noda, Isao

    2008-06-01

    As a traditional Chinese medicine (TCM), 'Red Flower Oil' preparation is widely used as a household remedy in China and Southeast Asia. Usually, the preparation is a mixture of several plant essential oils with different volatile features, such as wintergreen oil, turpentine oil and clove oil. The proportions of these plant essential oils in 'Red Flower Oil' vary from different manufacturers. Thus, it is important to develop a simple and rapid evaluation method for quality assurance of the preparations. Fourier transform infrared (FT-IR) was applied and two-dimensional correlation infrared spectroscopy (2D IR) based on the volatile characteristic of samples was used to enhance the resolution of FT-IR spectra. 2D IR technique could, not only easily provide the composition and their volatile sequences in 'Red flower Oil' preparations, but also rapidly discriminate the subtle differences in products from different manufacturers. Therefore, FT-IR combined with volatility-dependent 2D IR correlation analysis provides a very fast and effective method for the quality control of essential oil mixtures in TCM.

  20. IR Cards: Inquiry-Based Introduction to Infrared Spectroscopy

    Science.gov (United States)

    Bennett, Jacqueline; Forster, Tabetha

    2010-01-01

    As infrared spectroscopy (IR) is frequently used in undergraduate organic chemistry courses, an inductive introduction to IR spectroscopy that uses index cards printed with spectra, structures, and chemical names is described. Groups of students are given an alphabetized deck of these "IR cards" to sort into functional groups. The students then…

  1. Supercontinuum based mid-IR imaging spectroscopy for cancer detection

    DEFF Research Database (Denmark)

    Bang, Ole; Møller, Uffe Visbech; Kubat, Irnis;

    2014-01-01

    The mid-infrared (IR) spectral region is of significant technical and scientific interest because most molecules display fundamental vibrational absorptions in this region, leaving distinct spectral fingerprints. To date, the limitations of mid-IR light sources, such as thermal emitters, low...... cancer detection with mid-IR imaging spectroscopy....

  2. Coherent 2D Spectroscopy and Control of Molecular Complexes

    Science.gov (United States)

    Brixner, Tobias

    2007-03-01

    Coherent two-dimensional femtosecond spectroscopy is used to investigate electronic couplings within molecular complexes. Third-order optical response functions are measured in a non-collinear three-pulse photon echo geometry with heterodyne signal detection. In combination with suitable simulations this allows recovering the delocalization of excited-state wavefunctions, their coupling, and the corresponding energy transport pathways, with nanometer spatial and femtosecond temporal resolution. Examples of multichromophoric systems are the FMO and the LH3 light-harvesting complexes from green sulfur bacteria and purple bacteria, respectively, for which energy transfer processes have been determined. Additional challenges arise if one is interested in the spectroscopy of photochemical rather than photophysical processes in molecular complexes: The product yields attained by a single femtosecond laser pulse are often very small, and hence time-dependent signals are hard to measure with good signal-to-noise ratio. In the context of coherent control, this implies that bond-breaking photochemistry in liquids is still difficult despite the many successes of optimal control in gas-phase photodissociation. In a novel accumulative scheme, macroscopic amounts of stable photoproducts are generated in an optimal fashion and with high product detection sensitivity. In connection with time-resolved spectroscopy, the accumulative scheme furthermore provides kinetic information on the pathways of low-efficiency chemical reaction channels. This was applied to investigate the photoconversion of green fluorescent protein.

  3. Distinction of three wood species by Fourier transform infrared spectroscopy and two-dimensional correlation IR spectroscopy

    Science.gov (United States)

    Huang, Anmin; Zhou, Qun; Liu, Junliang; Fei, Benhua; Sun, Suqin

    2008-07-01

    Dalbergia odorifera T. Chen, Pterocarpus santalinus L.F. and Pterocarpus soyauxii are three kinds of the most valuable wood species, which are hard to distinguish. In this paper, differentiation of D. odorifera, P. santalinus and P. soyauxii was carried out by using Fourier transform infrared spectroscopy (FT-IR), second derivative IR spectra and two-dimensional correlation infrared (2D-IR) spectroscopy. The three woods have their characteristic peaks in conventional IR spectra. For example, D. odorifera has obvious absorption peaks at 1640 and 1612 cm -1; P. santalinus has only one peak at 1614 cm -1; and P. soyauxii has one peak at 1619 cm -1 and one shoulder peak at 1597 cm -1. To enhance spectrum resolution and amplify the differences between the IR spectra of different woods, the second derivative technology was adopted to examine the three wood samples. More differences could be observed in the region of 800-1700 cm -1. Then, the thermal perturbation is applied to distinguish different wood samples in an easier way, because of the spectral resolution being enhanced by the 2D correlation spectroscopy. In the region of 1300-1800 cm -1, D. odorifera has five auto-peaks at 1518, 1575, 1594, 1620 and 1667 cm -1; P. santalinus has four auto-peaks at 1469, 1518, 1627 and 1639 cm -1 and P. soyauxii has only two auto-peaks at 1627 and 1639 cm -1. It is proved that the 2D correlation IR spectroscopy can be a new method to distinguish D. odorifera, P. santalinus and P. soyauxii.

  4. Resonant photothermal IR spectroscopy of picogram samples with microstring resonator

    DEFF Research Database (Denmark)

    Yamada, Shoko; Schmid, Silvan; Boisen, Anja

    2013-01-01

    an in-situ sampling method and the resonance frequency of the string is measured optically. Resonance frequency shifts, proportional to the absorbed heat, are recorded in real time as monochromatic infrared light is being scanned over the mid-infrared range. These resonant photothermal IR spectroscopy......Here, we report a demonstration of resonant photothermal IR spectroscopy using microstrings in mid-infrared region providing rapid identification of picogram samples. In our microelectromechanical resonant photothermal IR spectroscopy system, samples are deposited directly on microstrings using...... spectra, obtained from picogram samples, suggest promising future applications of this approach....

  5. A 2-D Array of Superconducting Magnesium Diboride (MgB2) Far-IR Thermal Detectors for Planetary Exploration

    Science.gov (United States)

    Lakew, Brook

    2009-01-01

    A 2-D array of superconducting Magnesium Diboride(MgB2) far IR thermal detectors has been fabricated. Such an array is intended to be at the focal plane of future generation thermal imaging far-IR instruments that will investigate the outer planets and their icy moons. Fabrication and processing of the pixels of the array as well as noise characterization of architectured MgB2 thin films will be presented. Challenges and solutions for improving the performance of the array will be discussed.

  6. Linearly Polarized IR Spectroscopy Theory and Applications for Structural Analysis

    CERN Document Server

    Kolev, Tsonko

    2011-01-01

    A technique that is useful in the study of pharmaceutical products and biological molecules, polarization IR spectroscopy has undergone continuous development since it first emerged almost 100 years ago. Capturing the state of the science as it exists today, "Linearly Polarized IR Spectroscopy: Theory and Applications for Structural Analysis" demonstrates how the technique can be properly utilized to obtain important information about the structure and spectral properties of oriented compounds. The book starts with the theoretical basis of linear-dichroic infrared (IR-LD) spectroscop

  7. Organic structure determination using 2-D NMR spectroscopy a problem-based approach

    CERN Document Server

    Simpson, Jeffrey H

    2011-01-01

    Organic Structure Determination Using 2-D NMR Spectroscopy: A Problem-Based Approach, Second Edition, provides an introduction to the use of two-dimensional (2-D) nuclear magnetic resonance (NMR) spectroscopy to determine organic structure. The book begins with a discussion of the NMR technique, while subsequent chapters cover instrumental considerations; data collection, processing, and plotting; chemical shifts; symmetry and topicity; through-bond effects; and through-space effects. The book also covers molecular dynamics; strategies for assigning resonances to atoms within a molecule; s

  8. Combination of transient 2D-IR experiments and ab initio computations sheds light on the formation of the charge-transfer state in photoexcited carbonyl carotenoids.

    Science.gov (United States)

    Di Donato, Mariangela; Segado Centellas, Mireia; Lapini, Andrea; Lima, Manuela; Avila, Francisco; Santoro, Fabrizio; Cappelli, Chiara; Righini, Roberto

    2014-08-14

    The excited state dynamics of carbonyl carotenoids is very complex because of the coupling of single- and doubly excited states and the possible involvement of intramolecular charge-transfer (ICT) states. In this contribution we employ ultrafast infrared spectroscopy and theoretical computations to investigate the relaxation dynamics of trans-8'-apo-β-carotenal occurring on the picosecond time scale, after excitation in the S2 state. In a (slightly) polar solvent like chloroform, one-dimensional (T1D-IR) and two-dimensional (T2D-IR) transient infrared spectroscopy reveal spectral components with characteristic frequencies and lifetimes that are not observed in nonpolar solvents (cyclohexane). Combining experimental evidence with an analysis of CASPT2//CASSCF ground and excited state minima and energy profiles, complemented with TDDFT calculations in gas phase and in solvent, we propose a photochemical decay mechanism for this system where only the bright single-excited 1Bu(+) and the dark double-excited 2Ag(-) states are involved. Specifically, the initially populated 1Bu(+) relaxes toward 2Ag(-) in 200 fs. In a nonpolar solvent 2Ag(-) decays to the ground state (GS) in 25 ps. In polar solvents, distortions along twisting modes of the chain promote a repopulation of the 1Bu(+) state which then quickly relaxes to the GS (18 ps in chloroform). The 1Bu(+) state has a high electric dipole and is the main contributor to the charge-transfer state involved in the dynamics in polar solvents. The 2Ag(-) → 1Bu(+) population transfer is evidenced by a cross peak on the T2D-IR map revealing that the motions along the same stretching of the conjugated chain on the 2Ag(-) and 1Bu(+) states are coupled.

  9. A post-processing framework for localized 2D MR spectroscopy in vivo

    International Nuclear Information System (INIS)

    We propose a post-processing framework for localized two-dimensional (2D) magnetic resonance spectroscopy (MRS) in vivo. Our framework consists of corrections on eddy current and subject motion along with the framework used in conventional analytical 2D nuclear magnetic resonance (NMR) spectroscopy. In the eddy current correction, the phases of the free induction decays (FIDs) of the metabolite 1H are corrected along the t2 direction by the phase of the FID of water 1H. The corrected FIDs are Fourier transformed along the t2 direction, and interferograms of F(t1, ω2) are calculated. In the motion correction, the zero-order phase of the N-acetyl aspartate (NAA) singlet peak for each t1 axis is corrected after correction of frequency drift. We applied this framework in phantom and human brain measurements in a 4.7 T whole-body MR system. Two-dimensional data were collected by the localized 2D constant-time correlation spectroscopy (CT-COSY) sequence. We used a phantom containing a brain metabolite mixture of NAA, creatine (Cr), glutamate (Glu), glutamine (Gln) and γ-amino butyric acid (GABA). We demonstrated the eddy current correction procedure in the phantom experiments and the subject motion correction in human measurements. Though asymmetric patterns of the singlets of NAA and Cr were shown around the peak along the F2 direction in the reconstructed phantom spectra without eddy current correction, symmetric patterns arose after the correction. The t1 noise caused by those singlets was found in the human brain spectra without motion correction. The t1 noise was sufficiently suppressed by the motion correction. Our proposed post-processing framework for localized 2D MRS can improve the quality of in vivo 2D spectra and may allow improved quantitation and robustness of in vivo 2D spectroscopy. (author)

  10. Characterization of Hydrogen Bonds by IR Spectroscopy

    Directory of Open Access Journals (Sweden)

    Vojta, D.

    2012-05-01

    Full Text Available In the identification and quantification of hydrogen bond, as one of the most abundant non-covalent interactions in phenomena like self-assembly and molecular recognition, IR spectrosopy has been employed as the most sensitive method. The performance of the high dilution method enables determination of the stability constant of hydrogen-bonded complex as one of the most important thermodynamic quantities used in their characterization. However, the alleged experimental simplicity of the mentioned method is loaded with errors originating not only from researcher intervention but also independent from it. The second source of error is particularly emphasized and elaborated in this paper, which is designed as the recipe for the successful characterization of hydrogen bonds. Besides the enumeration of all steps in the determination of hydrogen-bonded stability constants, the reader can be acquainted with the most important ex perimental conditions that should be fulfilled in order to minimize the naturally occurring errors in this type of investigation. In the spectral analysis, the application of both uni- and multivariate approach has been discussed. Some computer packages, considering the latter, are mentioned, described, and recommended. KUI -10/2012Received August 1, 2011Accepted October 24, 2011

  11. 2D-Cosy NMR Spectroscopy as a Quantitative Tool in Biological Matrix: Application to Cyclodextrins.

    Science.gov (United States)

    Dufour, Gilles; Evrard, Brigitte; de Tullio, Pascal

    2015-11-01

    Classical analytical quantifications in biological matrices require time-consuming sample pre-treatments and extractions. Nuclear magnetic resonance (NMR) analysis does not require heavy sample treatments or extractions which therefore increases its accuracy in quantification. In this study, even if quantitative (q)NMR could not be applied to 2D spectra, we demonstrated that cross-correlations and diagonal peak intensities have a linear relationship with the analyzed pharmaceutical compound concentration. This work presents the validation process of a 2D-correlation spectroscopy (COSY) NMR quantification of 2-hydroxypropyl-β-cyclodextrin in plasma. Specificity, linearity, precision (repeatability and intermediate precision), trueness, limits of quantification (LOQs), and accuracy were used as validation criteria. 2D-NMR could therefore be used as a valuable and accurate analytical technique for the quantification of pharmaceutical compounds, including hardly detectable compounds such as cyclodextrins or poloxamers, in complex biological matrices based on a calibration curve approach.

  12. Stable and high-power few cycle supercontinuum for 2D ultrabroadband electronic spectroscopy.

    Science.gov (United States)

    Spokoyny, Boris; Koh, Christine J; Harel, Elad

    2015-03-15

    Broadband supercontinuum (SC) pulses in the few cycle regime are a promising source for spectroscopic and imaging applications. However, SC sources are plagued by poor stability, greatly limiting their utility in phase-resolved nonlinear experiments such as 2D photon echo spectroscopy (2D PES). Here, we generated SC by two-stage filamentation in argon and air starting from 100 fs input pulses, which are sufficiently high-power and stable to record time-resolved 2D PE spectra in a single laser shot. We obtain a total power of 400 μJ/pulse in the visible spectral range of 500-850 nm and, after compression, yield pulses with duration of 6 fs according to transient-grating frequency-resolved optical gating (TG-FROG) measurements. We demonstrate the method on the laser dye, Cresyl Violet, and observe coherent oscillations indicative of nuclear wavepacket dynamics.

  13. Location Detection and Tracking of Moving Targets by a 2D IR-UWB Radar System

    Directory of Open Access Journals (Sweden)

    Van-Han Nguyen

    2015-03-01

    Full Text Available In indoor environments, the Global Positioning System (GPS and long-range tracking radar systems are not optimal, because of signal propagation limitations in the indoor environment. In recent years, the use of ultra-wide band (UWB technology has become a possible solution for object detection, localization and tracking in indoor environments, because of its high range resolution, compact size and low cost. This paper presents improved target detection and tracking techniques for moving objects with impulse-radio UWB (IR-UWB radar in a short-range indoor area. This is achieved through signal-processing steps, such as clutter reduction, target detection, target localization and tracking. In this paper, we introduce a new combination consisting of our proposed signal-processing procedures. In the clutter-reduction step, a filtering method that uses a Kalman filter (KF is proposed. Then, in the target detection step, a modification of the conventional CLEAN algorithm which is used to estimate the impulse response from observation region is applied for the advanced elimination of false alarms. Then, the output is fed into the target localization and tracking step, in which the target location and trajectory are determined and tracked by using unscented KF in two-dimensional coordinates. In each step, the proposed methods are compared to conventional methods to demonstrate the differences in performance. The experiments are carried out using actual IR-UWB radar under different scenarios. The results verify that the proposed methods can improve the probability and efficiency of target detection and tracking.

  14. Location detection and tracking of moving targets by a 2D IR-UWB radar system.

    Science.gov (United States)

    Nguyen, Van-Han; Pyun, Jae-Young

    2015-01-01

    In indoor environments, the Global Positioning System (GPS) and long-range tracking radar systems are not optimal, because of signal propagation limitations in the indoor environment. In recent years, the use of ultra-wide band (UWB) technology has become a possible solution for object detection, localization and tracking in indoor environments, because of its high range resolution, compact size and low cost. This paper presents improved target detection and tracking techniques for moving objects with impulse-radio UWB (IR-UWB) radar in a short-range indoor area. This is achieved through signal-processing steps, such as clutter reduction, target detection, target localization and tracking. In this paper, we introduce a new combination consisting of our proposed signal-processing procedures. In the clutter-reduction step, a filtering method that uses a Kalman filter (KF) is proposed. Then, in the target detection step, a modification of the conventional CLEAN algorithm which is used to estimate the impulse response from observation region is applied for the advanced elimination of false alarms. Then, the output is fed into the target localization and tracking step, in which the target location and trajectory are determined and tracked by using unscented KF in two-dimensional coordinates. In each step, the proposed methods are compared to conventional methods to demonstrate the differences in performance. The experiments are carried out using actual IR-UWB radar under different scenarios. The results verify that the proposed methods can improve the probability and efficiency of target detection and tracking. PMID:25808773

  15. Critical Slowing of Density Fluctuations Approaching the Isotropic-Nematic Transition in Liquid Crystals: 2D IR Measurements and Mode Coupling Theory.

    Science.gov (United States)

    Sokolowsky, Kathleen P; Bailey, Heather E; Hoffman, David J; Andersen, Hans C; Fayer, Michael D

    2016-07-21

    Two-dimensional infrared (2D IR) data are presented for a vibrational probe in three nematogens: 4-cyano-4'-pentylbiphenyl, 4-cyano-4'-octylbiphenyl, and 4-(trans-4-amylcyclohexyl)-benzonitrile. The spectral diffusion time constants in all three liquids in the isotropic phase are proportional to [T*/(T - T*)](1/2), where T* is 0.5-1 K below the isotropic-nematic phase transition temperature (TNI). Rescaling to a reduced temperature shows that the decays of the frequency-frequency correlation function (FFCF) for all three nematogens fall on the same curve, suggesting a universal dynamic behavior of nematogens above TNI. Spectral diffusion is complete before significant orientational relaxation in the liquid, as measured by optically heterodyne detected-optical Kerr effect (OHD-OKE) spectroscopy, and before any significant orientational randomization of the probe measured by polarization selective IR pump-probe experiments. To interpret the OHD-OKE and FFCF data, we constructed a mode coupling theory (MCT) schematic model for the relationships among three correlation functions: ϕ1, a correlator for large wave vector density fluctuations; ϕ2, the orientational correlation function whose time derivative is the observable in the OHD-OKE experiment; and ϕ3, the FFCF for the 2D IR experiment. The equations for ϕ1 and ϕ2 match those in the previous MCT schematic model for nematogens, and ϕ3 is coupled to the first two correlators in a straightforward manner. Resulting models fit the data very well. Across liquid crystals, the temperature dependences of the coupling constants show consistent, nonmonotonic behavior. A remarkable change in coupling occurs at ∼5 K above TNI, precisely where the rate of spectral diffusion in 5CB was observed to deviate from that of a similar nonmesogenic liquid. PMID:27363680

  16. Differentiation of enantiomers by 2D NMR spectroscopy at 1 T using residual dipolar couplings.

    Science.gov (United States)

    Koos, Martin R M; Danieli, Ernesto; Casanova, Federico; Blümich, Bernhard; Luy, Burkhard

    2016-06-01

    Differentiating enantiomers using 2D bench-top NMR spectroscopy. Spectrometers working with permanent magnets at 1 T field strength allow the acquisition of 2D data sets. In conjunction with previously reported chiral alignment media, this setup allows the measurement of enantiomeric excess via residual dipolar couplings in stretched gelatine as a result of the reduced line width obtained by 2D J-resolved spectroscopy. PMID:25773020

  17. Terahertz Spectroscopy and Global Analysis of the Bending Vibrations of Acetylene 12C2D2

    Science.gov (United States)

    Yu, Shanshan; Drouin, Brian J.; Pearson, John C.; Pickett, Herbert M.; Lattanzi, Valerio; Walters, Adam

    2009-06-01

    Two hundred and fifty-one 12C2D2 transitions have been measured in the 0.2-1.6 THz region of its ν5-ν4 difference band and 202 of them were observed for the first time. The accuracy of these measurements is estimated to be ranging from 50 kHz to 100 kHz. The 12C2D2 molecules were generated under room temperature by passing 120-150 mTorr D2O vapor through calcium carbide (CaC2) powder. A multistate analysis was carried out for the bending vibrational modes ν4 and ν5 of 12C2D2, which includes the lines observed in this work and prior microwave, far-infrared and infrared data on the pure bending levels. Significantly improved molecular parameters were obtained for 12C2D2 by adding the new measurements to the old data set, which had only 10 lines with microwave measurement precision. New frequency and intensity predictions have been made based on the obtained molecular parameters. The more precise measurements and new predictions reported here will support the analyses of astronomical observations by the future high-resolution spectroscopy telescopes such as Herschel, SOFIA, and ALMA, which will work in the terahertz spectral region.

  18. Broadband 2D electronic spectroscopy reveals a carotenoid dark state in purple bacteria.

    Science.gov (United States)

    Ostroumov, Evgeny E; Mulvaney, Rachel M; Cogdell, Richard J; Scholes, Gregory D

    2013-04-01

    Although the energy transfer processes in natural light-harvesting systems have been intensively studied for the past 60 years, certain details of the underlying mechanisms remain controversial. We performed broadband two-dimensional (2D) electronic spectroscopy measurements on light-harvesting proteins from purple bacteria and isolated carotenoids in order to characterize in more detail the excited-state manifold of carotenoids, which channel energy to bacteriochlorophyll molecules. The data revealed a well-resolved signal consistent with a previously postulated carotenoid dark state, the presence of which was confirmed by global kinetic analysis. The results point to this state's role in mediating energy flow from carotenoid to bacteriochlorophyll.

  19. Electron spectroscopy of rubber and resin-based composites containing 2D carbon

    Energy Technology Data Exchange (ETDEWEB)

    Kaciulis, S., E-mail: saulius.kaciulis@ismn.cnr.it [Institute for the Study of Nanostructured Materials, ISMN-CNR, P.O. Box 10, Monterotondo Stazione, 00015 Roma (Italy); Mezzi, A.; Balijepalli, S.K. [Institute for the Study of Nanostructured Materials, ISMN-CNR, P.O. Box 10, Monterotondo Stazione, 00015 Roma (Italy); Lavorgna, M. [Institute of Polymers, Composites and Biomaterials, IPCB-CNR, P.le Fermi, 80055 Napoli (Italy); Xia, H.S. [State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, 610065 Sichuan (China)

    2015-04-30

    Composite materials with 2D carbon (graphene and/or single wall carbon nanotubes) are very promising due to their extraordinary electrical and mechanical properties. Graphene and natural rubber composites, which may be used for the gaskets or sealants, were prepared by ultrasonically assisted latex-mixing exfoliation and in-situ reduction process, with two vulcanization approaches: roll-mixing and hot-pressing. Also the resin-based composites, filled with micro-particles of Ag and graphene or carbon nanotubes, have been studied. The standards for the compositional characterization of these materials still are not established. In addition to the mostly used techniques, such as Raman spectroscopy and electron microscopy, also Auger electron spectroscopy can be employed for the identification of graphene. In this study, the shape of C KVV peak, excited by electron beam and X-ray photons, has been investigated in different composite materials containing graphene and carbon nanotubes. A spectroscopic method for 2D carbon recognition, based on the D{sub x} parameter which is determined from C KVV signal excited by X-ray photons, was proposed and verified. Even a small content of graphene in different types of composites was sufficient for this recognition due to the dominating presence of graphene on the surface of composites. - Highlights: • Chemical composition of the rubber composites was determined by XPS. • Auger spectrum of carbon was used for graphene identification in composites. • Small content of graphene was sufficient for its recognition from the D parameter.

  20. Broadband 2D Electronic Spectroscopy Reveals Coupling Between Dark 1Bu- State of Carotenoid and Qx State of Bacteriochlorophyll

    Directory of Open Access Journals (Sweden)

    Scholes Gregory D.

    2013-03-01

    Full Text Available The study of LH2 protein of purple bacteria by broadband 2D electronic spectroscopy is presented. The dark 1Bu- carotenoid state is directly observed in 2D spectra and its role in carotenoid-bacteriochlorophyll interaction is discussed.

  1. Detection of 2D phase transitions at the electrode/electrolyte interface using electrochemical impedance spectroscopy

    Science.gov (United States)

    Tymoczko, Jakub; Colic, Viktor; Bandarenka, Aliaksandr S.; Schuhmann, Wolfgang

    2015-01-01

    The capacitance of the electric double layer, CDL, formed at the electrode/electrolyte interface is generally determined by electrochemical impedance spectroscopy (EIS). However, CDL values obtained using EIS data often depend on the ac frequency of the potential perturbation used in EIS. The reasons for the observed frequency dispersions can be various, and hence extracting valuable information about the status of the electrified interface is not possible with the required certainty. In this work, using well-understood electrochemical systems, namely Pt(111) electrodes in contact with a series of acidic sulfate ions containing electrolytes, we provide strong evidence that 2D phase transitions in the adsorbate layers and, in general, structural effects at the electrode/electrolyte interface are in many cases responsible for the frequency dispersion of the double layer capacitance. These empirical findings open new opportunities for the detection and evaluation of 2D phase transition processes and other structural effects using EIS, even in presence of simultaneously occurring electrochemical processes. However, further theoretical elaboration of this effect is necessary.

  2. Structural Characterization of Lignins Isolated from Caragana sinica Using FT-IR and NMR Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    XIAOLing-ping; SHIZheng-jun; XUFeng; SUN Run-cang; Amar Kmohanty

    2011-01-01

    In order to efficiently explore and use woody biomass,six lignin fractions were isolated from dewaxed Caragana sinica via successive extraction with organic.solvents and alkaline solutions.The lignin structures were characterized by Fourier transform infrared spectroscopy (FT-IR) and 1D and 2D Nuclear Magnetic Resonance (NMR).FT-IR spectra revealed that the “core” of the lignin structure did not significantly change during the treatment under the conditions given.The results of 1 H and 13C NMR demonstrated that the lignin fraction L2,isolated with 70% ethanol containing 1% NaOH,was mainly composed of β-O-4 ether bonds together with G and S units and trace p-hydroxyphenyl unit.Based on the 2D HSQC NMR spectrum,the ethanol organosolv lignin fraction L1,extracted with 70% ethanol,presents a predominance of β-O-4' arylether linkages (61% of total side chains),and a low abundance of condensed carbon-carbon linked structures (such as β-β',β-1',and β-5') and a lower S/G ratio.Furthermore,a small percentage (ca.9%) of the linkage side chain was found to be acylated at the γ-carbon.

  3. Study of the deuterated albumin by FT-IR spectroscopy

    International Nuclear Information System (INIS)

    The albumin is a protein from the soluble or corpuscular protein class, which exists in cells, in dissolved state or in form of a hydrated gel. Proteins are essential constituents beside water, inorganic salts, lipids, carbon hydrates, vitamins, enzymes. The albumin is also a protein soluble in water and in diluted electrolyte solutions (acids, bases and salts). The investigation of the vibration isotopic effect has a great importance both for the diatomic molecules and for the polyatomic molecules. This paper is the first from a series of works which are intended to study the physico-chemical properties of the deuterated albumin and of the albumin solutions in heavy water by an isotopic exchange method. To put in evidence H-D exchange, the FT-IR spectroscopy is used when the deuterated albumin has different layer thickness. It is also of interest to elucidate the isotopic exchange between the hydrogen and oxygen atoms in bovine serum albumin macromolecules. (authors)

  4. Investigating the Hydration of CM2 meteorites by IR spectroscopy

    CERN Document Server

    Góbi, S; Beck, P; Quirico, E; Schmidt, B

    2014-01-01

    Chondritic meteorites are of great interest since they are one of the most ancient remnants of the early solar system. Some of them, like the carbonaceous CM meteorites experienced aqueous alteration thus their olivine content transformed more or less into hydrated silicates such as phyllosilicates. These hydrated CM2 meteorites have been investigated in KBr pellets by means of Fourier transform infrared (FT-IR) spectroscopy. In our focus of interest was to study the 3 and 10 $\\mu$m (3000 and 1000 cm$^{-1}$, the O$-$H and silicate streching) bands of several CM2 chondrites. By investigating these signals the water content and the extent of hydration can be determined. In order to achieve this, development of a new pellet production method was essential. This technique facilitates the elimination of adsorbed water coming from the surrounding environment, which would complicate correct interpretation of the results.

  5. Differentiation of Leishmania species by FT-IR spectroscopy

    Science.gov (United States)

    Aguiar, Josafá C.; Mittmann, Josane; Ferreira, Isabelle; Ferreira-Strixino, Juliana; Raniero, Leandro

    2015-05-01

    Leishmaniasis is a parasitic infectious disease caused by protozoa that belong to the genus Leishmania. It is transmitted by the bite of an infected female Sand fly. The disease is endemic in 88 countries Desjeux (2001) [1] (16 developed countries and 72 developing countries) on four continents. In Brazil, epidemiological data show the disease is present in all Brazilian regions, with the highest incidences in the North and Northeast. There are several methods used to diagnose leishmaniasis, but these procedures have many limitations, are time consuming, have low sensitivity, and are expensive. In this context, Fourier Transform Infrared Spectroscopy (FT-IR) analysis has the potential to provide rapid results and may be adapted for a clinical test with high sensitivity and specificity. In this work, FT-IR was used as a tool to investigate the promastigotes of Leishmaniaamazonensis, Leishmaniachagasi, and Leishmaniamajor species. The spectra were analyzed by cluster analysis and deconvolution procedure base on spectra second derivatives. Results: cluster analysis found four specific regions that are able to identify the Leishmania species. The dendrogram representation clearly indicates the heterogeneity among Leishmania species. The band deconvolution done by the curve fitting in these regions quantitatively differentiated the polysaccharides, amide III, phospholipids, proteins, and nucleic acids. L. chagasi and L. major showed a greater biochemistry similarity and have three bands that were not registered in L. amazonensis. The L. amazonensis presented three specific bands that were not recorded in the other two species. It is evident that the FT-IR method is an indispensable tool to discriminate these parasites. The high sensitivity and specificity of this technique opens up the possibilities for further studies about characterization of other microorganisms.

  6. VLT/VIMOS integral field spectroscopy of luminous and ultraluminous infrared galaxies: 2D kinematic properties

    CERN Document Server

    Bellocchi, Enrica; Colina, Luis; Miralles-Caballero, Daniel

    2013-01-01

    We present and discuss the 2D kinematic properties of the ionized gas (Halpha) in a sample of 38 local (ultra) luminous infrared galaxies [(U)LIRGs] (31 LIRGs and 7 ULIRGs) observed with VIMOS at the VLT using integral field spectroscopy. This sample covers well the less studied LIRG luminosity range and includes isolated disks, interacting systems, and mergers. The majority of the galaxies have two main kinematically distinct components. One component (i.e., narrow or systemic) extends over the whole line-emitting region and is characterized by small to intermediate velocity dispersions (i.e., sigma from 30 to 160 km s^-1). It traces the overall velocity field. The second component (broad) has in general a larger velocity dispersion (up to 320 km s^-1), mainly found in the inner regions and generally blueshifted with respect to the systemic component. Most of the objects (76%) are dominated by rotation, more relevant in LIRGs than in ULIRGs. Isolated disks, interacting galaxies, and merging systems define a ...

  7. Study of aging in oil paintings by 1D and 2D NMR spectroscopy.

    Science.gov (United States)

    Spyros, Apostolos; Anglos, Demetrios

    2004-09-01

    Nuclear magnetic resonance spectroscopy is proposed as an efficient analytical tool in the study of painted artworks. The binding medium from two original oil paintings, dated from the early 20th and the late 17th century, was studied via high-resolution 1D and 2D NMR, establishing the advanced state of hydrolysis and oxidation of the oil paint. Studies of the solvent-extractable component from model samples of various drying oils, raw oil paints, and aged oil paints allowed the definition of several markers based on the integral ratios of various chemical species present in the 1H and 13C NMR spectra. These markers are sensitive to hydrolytic and oxidative processes that reflect the extent of aging in oil paintings. The rapidity, simplicity, and nondestructive nature of the proposed analytical NMR methodology represents a great advantage, since the usually minute sample quantities available from original artwork can be subsequently analyzed further by other analytical techniques, if necessary. PMID:15373425

  8. Rapid authentication of different ages of tissue-cultured and wild Dendrobium huoshanense as well as wild Dendrobium henanense using FTIR and 2D-COS IR

    Science.gov (United States)

    Chen, Nai-Dong; Chen, Nai-Fu; Li, Jun; Cao, Cai-Yun; Wang, Jin-Mei

    2015-12-01

    The accumulating of pharmaceutical chemicals in medicinal plants would greatly be affected by their ages and establishing a fast quality-identification method to evaluate the similarity of medicinal herbs at different cultivated ages is a critical step for assurance of quality and safety in the TCM industry. In this work, tri-step IR macro-fingerprinting and 2D-COS IR spectrum techniques combined with statistical pattern recognition were applied for discrimination and similarity evaluation of different ages of tissue-cultured and wild Dendrobium huoshanense C. Z. Tang et S. J. Cheng as well as Dendrobium henanense J.L.Lu et L.X Gao. Both tissue-cultured and wild D. huoshanense were easily differentiated from D. henanense by FTIR and SD-IR spectra, while it's quite difficult to discriminate different cultivated years of the three investigated Dendrobiums. In 2D-COS IR spectra, 1-5 auto-peaks with different indensity and positions were located in the region 1160-1030 cm-1 of the twelve Dendrobium samples and thus could be used to identify Dendrobium samples at different ages. Principle component analysis (PCA) of synchronous 2D-COS data showed that the twelve samples were effectively identified and evaluated. The results indicated that the tri-step infrared macro-fingerprinting combined with PCA method was suitable to differentiate the cultivated ages of Dendrobiums with species and orgins rapidly and nondestructively.

  9. Impedance- and IR-spectroscopy on sputtered borate glasses

    International Nuclear Information System (INIS)

    Ion-conducting oxide glasses are considered as components of thin film batteries. In our study, glass films of the compositions xLi2O.(1-x)B2O3 with x=0.15, 0.20, 0.25, 0.30, and 0.35 are prepared by ion beam sputtering in a thickness range between 100 and 1000 nm. TEM cross section investigations show a homogeneous, amorphous structure of the films, while the correspondence of their chemical composition with the glass targets is proved by EELS analysis. The specific dc-conductivity of the glass films is determined by temperature-dependent impedance spectroscopy and found to be up to three orders of magnitude higher compared to the conductivity of the corresponding bulk glasses prepared from the melt. This conductivity increase is explained by a modification of the network structure of the thin glass films. The concentration of the Non-Bridging Oxygen atoms of the network is assumed to be increased by the sputter process. This increase is expected to be the main reason for the observed conductivity enhancement. IR-spectroscopy is used to determine the content of the Non-Bridging Oxygen atoms of the network, to correlate structural and electrical properties of the thin film glasses

  10. Structure of a model salt bridge in solution investigated with 2D-​IR spectroscopy

    NARCIS (Netherlands)

    A. Huerta-Viga; S.R. Domingos; S. Amirjalayer; S. Woutersen

    2013-01-01

    Salt bridges are known to be important for the stability of protein conformation, but up to now it has been difficult to study their geometry in soln. Here we characterize the spatial structure of a model salt bridge between guanidinium (Gdm+) and acetate (Ac-​) using two-​dimensional vibrational (2

  11. Acid epimerization of 20-keto pregnane glycosides is determined by 2D-NMR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Victor P., E-mail: vpergarw@gobiernodecanarias.org [Instituto de Productos Naturales de Canarias, Departamento de Quimica de Productos Naturales y Biotecnologia (Spain)

    2011-05-15

    Carbohydrates influence many essential biological events such as apoptosis, differentiation, tumor metastasis, cancer, neurobiology, immunology, development, host-pathogen interactions, diabetes, signal transduction, protein folding, and many other contexts. We now report on the structure determination of pregnane glycosides isolated from the aerial parts of Ceropegia fusca Bolle (Asclepiadaceae). The observation of cicatrizant, vulnerary and cytostatic activities in some humans and animals of Ceropegia fusca Bolle, a species endemic to the Canary Islands, encouraged us to begin a pharmacological study to determine their exact therapeutic properties. High resolution {sup 1}H-NMR spectra of pregnane glycosides very often display well-resolved signals that can be used as starting points in several selective NMR experiments to study scalar (J coupling), and dipolar (NOE) interactions. ROESY is especially suited for molecules such that {omega}{tau}{sub c} {approx} 1, where {tau}{sub c} are the motional correlation times and {omega} is the angular frequency. In these cases the NOE is nearly zero, while the rotating-frame Overhauser effect spectroscopy (ROESY) is always positive and increases monotonically for increasing values of {tau}{sub c}. The ROESY shows dipolar interactions cross peaks even in medium-sized molecules which are helpful in unambiguous assignment of all the interglycosidic linkages. Selective excitation was carried out using a double pulsed-field gradient spin-echo sequence (DPFGSE) in which 180 Degree-Sign Gaussian pulses are sandwiched between sine shaped z-gradients. Scalar interactions were studied by homonuclear DPFGSE-COSY and DPFGSE-TOCSY experiments, while DPFGSE-ROESY was used to monitor the spatial environment of the selectively excited proton. Dipolar interactions between nuclei close in space can be detected by the 1D GROESY experiment, which is a one-dimensional counterpart of the 2D ROESY method. The C-12 and C-17 configurations were

  12. Moving-window 2D correlation spectroscopy in studies of fluphenazine-DPPC dehydrated film as a function of temperature

    Science.gov (United States)

    Szwed, Joanna; Cieślik-Boczula, Katarzyna; Czarnik-Matusewicz, Bogusława; Jaszczyszyn, Agata; Gąsiorowski, Kazimierz; Świątek, Piotr; Malinka, Wiesław

    2010-06-01

    The effect of incorporating fluphenazine (FPh) into the dipalmitoylphosphatidylcholine (DPPC) multibilayers was studied by means of two-dimensional correlation spectroscopy (2DCOS) applied to attenuated total reflection (ATR) infrared spectra. DPPC is used as a model membrane that mimics the organization of lipids in biological membranes and their interaction with FPh. ATR-IR spectra for both DPPC dry film alone and the film doped with FPh were recorded as a function of temperature to provide information about the interaction between FPh molecules and DPPC lipid. The chain-melting phase-transition temperature changes are strictly correlated with the conformational order of the lipid hydrocarbon chains. To gain deeper insight into the accompanying spectral changes, we employed moving-window 2D correlation spectroscopy. Subdividing all the measurements from 10 to 90 °C into 20° subsets enables a detailed identification of spectral features induced by embedding FPh into DPPC multilayers. Moving-window analysis of the power spectra for the ν asym,symCH 2, δ sCH 2, and δ rCH 2 vibrations provides evidence that FPh is embedded in the region between the bilayers, penetrating their hydrophilic part, which destabilizes the interchain interaction. Above 60 °C the FPh-DPPC system reaches the liquid crystalline phase with the well-established location of FPh. A further temperature increase to 90 °C has little effect on the intrachain conformational order and the packing character of the FPh-DPPC system in the liquid crystalline phase. In addition, FPh hinders the formation of large domains. Comparison of the moving-window analysis done by using slice spectra for DPPC and FPh-doped DPPC dry film for ν asym,symCH 2, νC dbnd O, and νPO2- shows that the interaction between the DPPC and FPh molecules is accompanied by very distinct spectral changes located in a both lower and narrower temperature range than those observed in pure DPPC film.

  13. Stereochemistry of 16a-Hydroxyfriedelin and 3-Oxo-16-methylfriedel-16-ene Established by 2D NMR Spectroscopy

    Directory of Open Access Journals (Sweden)

    Vagner Fernandes Knupp

    2009-02-01

    Full Text Available Friedelin (1, 3b-friedelinol (2, 28-hydroxyfriedelin (3, 16a-hydroxyfriedelin (4, 30-hydroxyfriedelin (5 and 16a,28-dihydroxyfriedelin (6 were isolated through fractionation of the hexane extract obtained from branches of Salacia elliptica. After a week in CDCl3 solution, 16a-hydroxyfriedelin (4 reacted turning into 3-oxo-16-methylfriedel-16-ene (7. This is the first report of a dehydration followed by a Nametkin rearrangement of a pentacyclic triterpene in CDCl3 solution occurring in the NMR tube. These seven pentacyclic triterpenes was identified through NMR spectroscopy and the stereochemistry of compound 4 and 7 was established by 2D NMR (NOESY spectroscopy and mass spectrometry (GC-MS. It is also the first time that all the 13C-NMR and 2D NMR spectral data are reported for compounds 4 and 7.

  14. 2D-Raman-THz spectroscopy: A sensitive test of polarizable water models

    Energy Technology Data Exchange (ETDEWEB)

    Hamm, Peter, E-mail: peter.hamm@chem.uzh.ch [Department of Chemistry, University of Zurich, Winterthurerstr. 190, CH-8057 Zürich (Switzerland)

    2014-11-14

    In a recent paper, the experimental 2D-Raman-THz response of liquid water at ambient conditions has been presented [J. Savolainen, S. Ahmed, and P. Hamm, Proc. Natl. Acad. Sci. U. S. A. 110, 20402 (2013)]. Here, all-atom molecular dynamics simulations are performed with the goal to reproduce the experimental results. To that end, the molecular response functions are calculated in a first step, and are then convoluted with the laser pulses in order to enable a direct comparison with the experimental results. The molecular dynamics simulation are performed with several different water models: TIP4P/2005, SWM4-NDP, and TL4P. As polarizability is essential to describe the 2D-Raman-THz response, the TIP4P/2005 water molecules are amended with either an isotropic or a anisotropic polarizability a posteriori after the molecular dynamics simulation. In contrast, SWM4-NDP and TL4P are intrinsically polarizable, and hence the 2D-Raman-THz response can be calculated in a self-consistent way, using the same force field as during the molecular dynamics simulation. It is found that the 2D-Raman-THz response depends extremely sensitively on details of the water model, and in particular on details of the description of polarizability. Despite the limited time resolution of the experiment, it could easily distinguish between various water models. Albeit not perfect, the overall best agreement with the experimental data is obtained for the TL4P water model.

  15. In vivo 1D and 2D correlation MR spectroscopy of the soleus muscle at 7T

    Science.gov (United States)

    Ramadan, Saadallah; Ratai, Eva-Maria; Wald, Lawrence L.; Mountford, Carolyn E.

    2010-05-01

    AimThis study aims to (1) undertake and analyse 1D and 2D MR correlation spectroscopy from human soleus muscle in vivo at 7T, and (2) determine T1 and T2 relaxation time constants at 7T field strength due to their importance in sequence design and spectral quantitation. MethodSix healthy, male volunteers were consented and scanned on a 7T whole-body scanner (Siemens AG, Erlangen, Germany). Experiments were undertaken using a 28 cm diameter detunable birdcage coil for signal excitation and an 8.5 cm diameter surface coil for signal reception. The relaxation time constants, T1 and T2 were recorded using a STEAM sequence, using the 'progressive saturation' method for the T1 and multiple echo times for T2. The 2D L-Correlated SpectroscopY (L-COSY) method was employed with 64 increments (0.4 ms increment size) and eight averages per scan, with a total time of 17 min. ResultsT1 and T2 values for the metabolites of interest were determined. The L-COSY spectra obtained from the soleus muscle provided information on lipid content and chemical structure not available, in vivo, at lower field strengths. All molecular fragments within multiple lipid compartments were chemically shifted by 0.20-0.26 ppm at this field strength. 1D and 2D L-COSY spectra were assigned and proton connectivities were confirmed with the 2D method. ConclusionIn vivo 1D and 2D spectroscopic examination of muscle can be successfully recorded at 7T and is now available to assess lipid alterations as well as other metabolites present with disease. T1 and T2 values were also determined in soleus muscle of male healthy volunteers.

  16. Transmittance, Reflectance, and Emission Spectroscopy of Meteorites from the UV to the IR Spectral Range

    Science.gov (United States)

    Maturilli, A.; Helbert, J.; Koulen, J. M.; Ferrari, S.; Martellato, E.

    2016-08-01

    Transmittance, reflectance, and emissivity Spectra of six meteorites have been collected at the Planetary Spectroscopy Laboratory (PSL) of DLR in Berlin in the whole spectral range from the UV to the IR.

  17. Infrared spectroscopy of radio-luminous OH/IR stars

    Science.gov (United States)

    Jones, Terry Jay; Hyland, A. R.; Fix, John D.; Cobb, Michael L.

    1988-01-01

    Low-resolution 1.5-2.5-micron spectra for 21 radio-luminous OH/IR stars are presented. These spectra divide into two broad classes. Those with very strong water-vapor absorption closely resemble the spectra of classical Mira variables and are classified Type VM. Those with weaker water-vapor absorption, but still showing strong CO absorption, resemble the spectra of true core-burning supergiants and are classified Type SG. Comparison of the classification of 30 radio-luminous OH/IR stars with their Delta(V)s and luminosities suggests this classification is a good indicator of the intrinsic nature of the underlying star. There is some evidence, however, that some true supergiants (massive main-sequence progenitors) develop the pulsation properties and photospheric characteristics of the Mira-like OH/IR stars when they become optically obscured OH/IR stars.

  18. Recovering the Fermi surface with 2D-ACAR spectroscopy in samples with defects

    International Nuclear Information System (INIS)

    When two-dimensional angular correlation of positron annihilation radiation (2D-ACAR) experiments are performed in metals containing defects, conventional analysis in which the measured momentum distribution is folded back into the first Brillouin zone is rendered ineffective due to the contribution from positrons annihilating from the defect. However, by working with the radial anisotropy of the spectrum, it is shown that an image of the Fermi surface can be recovered since the defect contribution is essentially isotropic.

  19. Recovering the Fermi surface with 2D-ACAR spectroscopy in samples with defects

    Science.gov (United States)

    Dugdale, S. B.; Laverock, J.

    2014-04-01

    When two-dimensional angular correlation of positron annihilation radiation (2D-ACAR) experiments are performed in metals containing defects, conventional analysis in which the measured momentum distribution is folded back into the first Brillouin zone is rendered ineffective due to the contribution from positrons annihilating from the defect. However, by working with the radial anisotropy of the spectrum, it is shown that an image of the Fermi surface can be recovered since the defect contribution is essentially isotropic.

  20. Nanomechanical IR Spectroscopy for the fast analysis of picogram samples of engineered nanomaterials

    DEFF Research Database (Denmark)

    Andersen, Alina Joukainen; Ek, Pramod Kumar; Andresen, Thomas Lars;

    2014-01-01

    The proliferation of engineered nanomaterials (ENMs), e.g. in nanomedicine, demands for novel sensitive techniques allowing for the analysis of minute samples. We present nanoelectromechanical system-based IR spectroscopy (NEMS-IR) of picograms of polymeric micelles. The micelles are nebulized...

  1. A new sequence for shaped voxel spectroscopy in the human brain using 2D spatially selective excitation and parallel transmission.

    Science.gov (United States)

    Waxmann, Patrick; Mekle, Ralf; Schubert, Florian; Brühl, Rüdiger; Kuehne, Andre; Lindel, Tomasz D; Seifert, Frank; Speck, Oliver; Ittermann, Bernd

    2016-08-01

    Spatially selective excitation in two dimensions (2D-SSE) utilizing parallel transmission was applied as a means to acquire signal from voxels adapted to the anatomy of interest for in vivo (1) H MR spectroscopy. A novel method to select spectroscopy voxels with arbitrary shapes in two dimensions was investigated. An on-off scheme with an adiabatic slice selective inversion pulse preceding a 2D-SSE pulse together with a segmented inward spiral excitation k-space trajectory enabled rapid free induction decay acquisitions. Performance of the sequence was evaluated in simulations, phantom experiments, and in vivo measurements at 3 T. High spatial fidelity of the excitation profile was achieved for different target shapes and with little off-resonance deterioration. Metabolite concentrations in human brain determined with the new sequence were quantified with Cramér-Rao lower bounds less than 20%. They were in the physiological range and did not deviate systematically from results acquired with a conventional SPECIAL sequence. In conclusion, a new approach for shaped voxel MRS in the human brain is presented, which complements existing sequences. Simulations show that 2D-SSE pulses yield reduced chemical shift artifact when compared with conventional localization methods. Copyright © 2016 John Wiley & Sons, Ltd. PMID:27254102

  2. FT-IR spectroscopy characterization of schwannoma: a case study

    Science.gov (United States)

    Ferreira, Isabelle; Neto, Lazaro P. M.; das Chagas, Maurilio José; Carvalho, Luís. Felipe C. S.; dos Santos, Laurita; Ribas, Marcelo; Loddi, Vinicius; Martin, Airton A.

    2016-03-01

    Schwannoma are rare benign neural neoplasia. The clinical diagnosis could be improved if novel optical techniques are performed. Among these techniques, FT-IR is one of the currently techniques which has been applied for samples discrimination using biochemical information with minimum sample preparation. In this work, we report a case of a schwannoma in the cervical region. A histological examination described a benign process. An immunohistochemically examination demonstrated positivity to anti-S100 protein antibody, indicating a diagnosis of schwannoma. The aim of this analysis was to characterize FT-IR spectrum of the neoplastic and normal tissue in the fingerprint (1000-1800 cm-1) and high wavenumber region (2800-3600 cm-1). The IR spectra were collect from tumor tissue and normal nerve samples by a FT-IR spectrophotometer (Spotlight Perkin Elmer 400, USA) with 64 scans, and resolution of 4 cm-1. A total of twenty spectra were recorded (10 from schwannoma and 10 from nerve). Multivariate Analysis was used to classify the data. Through average and standard deviation analysis we observed that the main spectral change occurs at ≍1600 cm-1 (amide I) and ≍1400 cm-1 (amide III) in the fingerprint region, and in CH2/CH3 protein-lipids and OH-water vibrations for the high wavenumber region. In conclusion, FT-IR could be used as a technique for schwannoma analysis helping to establish specific diagnostic.

  3. 2D-correlation analysis applied to in situ and operando Mossbauer spectroscopy

    OpenAIRE

    Aldon, Laurent; Perea, Alexis

    2011-01-01

    In this paper we propose a new way for Mossbauer data treatment when numerous experimental spectra are recorded in operando conditions depending on a perturbation. In our example, the perturabation is the Li amount extracted from a positive electrode material LiFe(0.75)Mn(0.25)PO(4). In other cases perturbation could be the recording temperature, the pressure or kinetic parameter or even time for isothermal experiments. From analysis of both synchronous and asynchronous 2D-correlation spectra...

  4. Nanomechanical IR spectroscopy for fast analysis of liquid-dispersed engineered nanomaterials

    DEFF Research Database (Denmark)

    Andersen, Alina Joukainen; Yamada, Shoko; Ek, Pramod Kumar;

    2016-01-01

    The proliferated use of engineered nanomaterials (ENMs), e.g. in nanomedicine, calls for novel techniques allowing for fast and sensitive analysis of minute samples. Here we present nanomechanical IR spectroscopy (NAM-IR) for chemical analysis of picograms of ENMs. ENMs are nebulized directly from...... dispersion and efficiently collected on nanomechanical string resonators through a non-diffusion limited sampling method. Even very small amounts of sample can convert absorbed IR light into a measurable frequency detuning of the string through photothermal heating. An IR absorption spectrum is thus readily...

  5. Determination of Dihydrobenzoacridinone Structures by NMR, IR, and UV Spectroscopy and Mass Spectrometry

    Science.gov (United States)

    Kozlov, N. G.; Zhiharko, Yu. D.; Skakovsky, E. D.; Baranovsky, A. V.; Ogorodnikova, M. M.; Basalaeva, L. I.

    2016-01-01

    Condensation of 2-naphthylamine, aromatic aldehydes, and dimedone was found to produce 9,10-dihydrobenzo[a] acridin-11-one derivatives according to PMR, 13C NMR, and IR spectroscopy and mass spectrometry. Correlation spectroscopy showed that the carbonyl in the synthesized dihydrobenzoacridinone derivatives was located on C11.

  6. [Analysis of streamer properties and emission spectroscopy of 2-D OH distribution of pulsed corona discharge].

    Science.gov (United States)

    Zhao, Lei; Gao, Xiang; Luo, Zhong-Yang; Xuan, Jian-Yong; Jiang, Jian-Ping; Cen, Ke-Fa

    2011-11-01

    Streamer plays a key role in the process of OH radical generation. The propagation of primary and secondary streamers of positive wire-plate pulsed corona discharge was observed using a short gate ICCD in air environment. The influence of the applied voltage on the properties was investigated. It was shown that the primary streamer propagation velocity, electric coverage and length of secondary streamer increased significantly with increasing the applied voltage. Then 2-D OH distribution was investigated by the emission spectrum. With the analysis of the OH emission spectra, the distribution of OH radicals showed a trend of decreasing from the wire electrode to its circumambience. Compared with the streamer propagation trace, the authors found that OH radical distribution and streamer are in the same area. Both OH radical concentration and the intensity of streamer decreased when far away from the wire electrode. PMID:22242481

  7. 2D-correlation analysis applied to in situ and operando Moessbauer spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Aldon, Laurent; Perea, Alexis [ICGM/AIME (UMR 5253 CNRS), CC 15-02, Universite Montpellier II, Place E. Bataillon, 34095 Montpellier Cedex 5 (France)

    2011-02-01

    In this paper we propose a new way for Moessbauer data treatment when numerous experimental spectra are recorded in operando conditions depending on a perturbation. In our example, the perturbation is the Li amount extracted from a positive electrode material LiFe{sub 0.75}Mn{sub 0.25}PO{sub 4}. In other cases perturbation could be the recording temperature, the pressure or kinetic parameter or even time for isothermal experiments. From analysis of both synchronous and asynchronous 2D-correlation spectra, we can focus our attention on the intensity variations at some specific positions deduced from cross-peaks. This analytical method is very powerful when overlap between absorption lines is observed. This is typically the case when Fe{sup 2+}/Fe{sup 3+} contributions are simultaneously present in a Moessbauer spectrum at lower velocities. (author)

  8. Spatially-resolved mid-ir spectroscopy of ngc 1068

    Directory of Open Access Journals (Sweden)

    R. E. Mason

    2006-01-01

    Full Text Available Presentamos espectros espacialmente resueltos, cercanos al l mite de difracci on, de 10 m, del n ucleo de la galaxia Seyfert 2 NGC 1068. Estos revelan variaciones notables en la pendiente del cont nuo, el per l y la profundidad del rasgo de silicato, y ujos de l neas de estructura na en escalas de subsegundos de arco, que ilustran en detalles sin precedente la complejidad de las regiones circunnuclares de esta galaxia en longitudes de onda del IR medio. Las im agenes de adquisici on muestran dos componentes distintos: una fuente brillante compacta (radio < 15 pc dentro de los 0.4 segarc centrales, identi cada con el toro obscurecedor de AGN, y una emisi on extendida, de brillo m as bajo proveniente del polvo de los conos de ionizaci on. El espectro observado de la fuente compacta se compara con modelos de toro grumoso, siendo esta la primera comparaci on detallada de estos modelos con observaciones. Los modelos requieren que la mayor parte de las nubes se localice dentro de unos cuantos parsecs de la m aquina central, lo cual concuerda muy bien con observaciones interferom etricas recientes del IR medio. Sin embargo, el ujo del IR medio medido con aperturas mayores de alrededor de 1 segarc est a dominado por la emisi on de polvo procedente de los conos de ionizaci on. Muchos de los intentos previos para determinar la distribuci on de la energ a espectral del toro estar an probablemente afectados por la contaminaci on procedente de la emisi on extendida, lo cual pone de relieve la importancia que la resoluci on espacial tiene para estudios IR de AGN cercanos.

  9. (13)C NMR assignments of regenerated cellulose from solid-state 2D NMR spectroscopy.

    Science.gov (United States)

    Idström, Alexander; Schantz, Staffan; Sundberg, Johan; Chmelka, Bradley F; Gatenholm, Paul; Nordstierna, Lars

    2016-10-20

    From the assignment of the solid-state (13)C NMR signals in the C4 region, distinct types of crystalline cellulose, cellulose at crystalline surfaces, and disordered cellulose can be identified and quantified. For regenerated cellulose, complete (13)C assignments of the other carbon regions have not previously been attainable, due to signal overlap. In this study, two-dimensional (2D) NMR correlation methods were used to resolve and assign (13)C signals for all carbon atoms in regenerated cellulose. (13)C-enriched bacterial nanocellulose was biosynthesized, dissolved, and coagulated as highly crystalline cellulose II. Specifically, four distinct (13)C signals were observed corresponding to conformationally different anhydroglucose units: two signals assigned to crystalline moieties and two signals assigned to non-crystalline species. The C1, C4 and C6 regions for cellulose II were fully examined by global spectral deconvolution, which yielded qualitative trends of the relative populations of the different cellulose moieties, as a function of wetting and drying treatments. PMID:27474592

  10. Performance improvements in temperature reconstructions of 2-D tunable diode laser absorption spectroscopy (TDLAS)

    Science.gov (United States)

    Choi, Doo-Won; Jeon, Min-Gyu; Cho, Gyeong-Rae; Kamimoto, Takahiro; Deguchi, Yoshihiro; Doh, Deog-Hee

    2016-02-01

    Performance improvement was attained in data reconstructions of 2-dimensional tunable diode laser absorption spectroscopy (TDLAS). Multiplicative Algebraic Reconstruction Technique (MART) algorithm was adopted for data reconstruction. The data obtained in an experiment for the measurement of temperature and concentration fields of gas flows were used. The measurement theory is based upon the Beer-Lambert law, and the measurement system consists of a tunable laser, collimators, detectors, and an analyzer. Methane was used as a fuel for combustion with air in the Bunsen-type burner. The data used for the reconstruction are from the optical signals of 8-laser beams passed on a cross-section of the methane flame. The performances of MART algorithm in data reconstruction were validated and compared with those obtained by Algebraic Reconstruction Technique (ART) algorithm.

  11. Far-field infrared super-resolution microscopy using picosecond time-resolved transient fluorescence detected IR spectroscopy

    Science.gov (United States)

    Sakai, Makoto; Kawashima, Yasutake; Takeda, Akihiro; Ohmori, Tsutomu; Fujii, Masaaki

    2007-05-01

    A new far-field infrared super-resolution microscopy combining laser fluorescence microscope and picosecond time-resolved transient fluorescence detected IR (TFD-IR) spectroscopy is proposed. TFD-IR spectroscopy is a kind of IR-visible/UV double resonance spectroscopy, and detects IR transitions by the transient fluorescence due to electronic transition originating from vibrationally excited level populated by IR light. IR images of rhodamine-6G solution and of fluorescent beads were clearly observed by monitoring the transient fluorescence. Super-resolution twice higher than the diffraction limit for IR light was achieved. The IR spectrum due to the transient fluorescence was also measured from spatial domains smaller than the diffraction limit.

  12. The performance of 2D array detectors for light sheet based fluorescence correlation spectroscopy.

    Science.gov (United States)

    Singh, Anand Pratap; Krieger, Jan Wolfgang; Buchholz, Jan; Charbon, Edoardo; Langowski, Jörg; Wohland, Thorsten

    2013-04-01

    Single plane illumination microscopy based fluorescence correlation spectroscopy (SPIM-FCS) is a new method for imaging FCS in 3D samples, providing diffusion coefficients, transport, flow velocities and concentrations in an imaging mode. SPIM-FCS records correlation functions over a whole plane in a sample, which requires array detectors for recording the fluorescence signal. Several types of image sensors are suitable for FCS. They differ in properties such as effective area per pixel, quantum efficiency, noise level and read-out speed. Here we compare the performance of several low light array detectors based on three different technologies: (1) Single-photon avalanche diode (SPAD) arrays, (2) passive-pixel electron multiplying charge coupled device (EMCCD) and (3) active-pixel scientific-grade complementary metal oxide semiconductor cameras (sCMOS). We discuss the influence of the detector characteristics on the effective FCS observation volume, and demonstrate that light sheet based SPIM-FCS provides absolute diffusion coefficients. This is verified by parallel measurements with confocal FCS, single particle tracking (SPT), and the determination of concentration gradients in space and time. While EMCCD cameras have a temporal resolution in the millisecond range, sCMOS cameras and SPAD arrays can extend the time resolution of SPIM-FCS down to 10 μs or lower. PMID:23571955

  13. Picosecond ir hole-burning spectroscopy on HDO ice Ih

    Science.gov (United States)

    Seifert, G.; Weidlich, K.; Graener, H.

    1997-12-01

    Transient hole-burning experiments using picosecond ir pulses in the region of the OH stretching vibration of crystalline HDO (in D2O) ice are reported; holes with a minimum width of 26 cm-1 are measured, proving the OH band to be inhomogeneously broadened. The inhomogeneous distribution having a half width of approximately 25 cm-1 can be related to structural disorder in ice. A vibrational lifetime of 0.5 ps<=T1<=2 ps is found for the OH stretching mode. Additional features in the transient data are attributed to the dissipation of excess energy; particularly microscopic energy flow in the immediate surroundings of primarily excited OH groups can be monitored.

  14. Comparison between ATR-IR, Raman, concatenated ATR-IR and Raman spectroscopy for the determination of total antioxidant capacity and total phenolic content of Chinese rice wine.

    Science.gov (United States)

    Wu, Zhengzong; Xu, Enbo; Long, Jie; Pan, Xiaowei; Xu, Xueming; Jin, Zhengyu; Jiao, Aiquan

    2016-03-01

    The application of attenuated total reflectance infrared spectroscopy (ATR-IR), Raman spectroscopy (RS) and combination of ATR-IR and RS for measurements of total antioxidant capacity (TAC) and total phenolic content (TPC) of Chinese rice wine (CRW) were investigated in this study. Synergy interval partial least-squares (SiPLS), support vector machine (SVM) and principal component analysis (PCA) were applied to process the merged data from two individual instruments. It was observed that the performances of models based on the RS spectra were better than those based on the ATR-IR spectra. In addition, SVM models based on the efficient information extracted from ATR-IR and RS spectra were superior to PLS models based on the same information and PLS models based on ATR-IR or RS spectra. The overall results demonstrated that integrating ATR-IR and RS was possible and could improve the prediction accuracy of TAC and TPC in CRWs.

  15. Detection of starch adulteration in onion powder by FT-NIR and FT-IR spectroscopy

    Science.gov (United States)

    Adulteration of onion powder with cornstarch was identified by Fourier transform near-infrared (FT-NIR) and Fourier transform infrared (FT-IR) spectroscopy. The reflectance spectra of 180 pure and adulterated samples (1–35 wt% starch) were collected and preprocessed to generate calibration and predi...

  16. Preparation of Phenolized Calcium Lignosulfonate andCharacterization of the Reaction by IR Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A kind of calcium lignosulfonate was phenolized by phenol with sulfuric acid as catalyst. The calcium lignosulfonate and its phenolized derivatives were characterized by infrared spectroscopy. It is proved that the extent and type of the phenolizing reaction can be deduced from the IR spectra of the calcium lignosulfonate and its phenolized derivatives.

  17. Monitoring lipase-catalyzed interesterification for bulky fats modification with FT-IR/NIR spectroscopy

    DEFF Research Database (Denmark)

    Chang, Tinghong; Lai, Xuxin; Zhang, Hong;

    2005-01-01

    This work demonstrates the application of FT-IR and FT-NIR spectroscopy to monitor the enzymatic interesterification process for bulky fat modification. The reaction was conducted between palm stearin and coconut oil (70/30, w/w) with the catalysis of Lipozyme TL IM at 70°C in a batch reactor...

  18. Solid Acid-Catalyzed Cellulose Hydrolysis Monitored by In Situ ATR-IR Spectroscopy

    NARCIS (Netherlands)

    Zakzeski, J.; Grisel, R.J.H.; Smit, A.T.; Weckhuysen, B.M.

    2012-01-01

    The solid acid-catalyzed hydrolysis of cellulose was studied under elevated temperatures and autogenous pressures using in situ ATR-IR spectroscopy. Standards of cellulose and pure reaction products, which include glucose, fructose, hydroxymethylfurfural (HMF), levulinic acid (LA), formic acid, and

  19. Structure Determination of Unknown Organic Liquids Using NMR and IR Spectroscopy: A General Chemistry Laboratory

    Science.gov (United States)

    Pavel, John T.; Hyde, Erin C.; Bruch, Martha D.

    2012-01-01

    This experiment introduced general chemistry students to the basic concepts of organic structures and to the power of spectroscopic methods for structure determination. Students employed a combination of IR and NMR spectroscopy to perform de novo structure determination of unknown alcohols, without being provided with a list of possible…

  20. Preliminary Discrimination of Cheese Adulteration by FT-IR Spectroscopy

    Directory of Open Access Journals (Sweden)

    Lucian Cuibus

    2014-11-01

    Full Text Available The present work describes a preliminary study to compare some traditional Romanian cheeses and adulterated cheeses using Attenuated Total Reflectance-Fourier transform infrared spectroscopy (ATR-FTIR. For PLS model calibration (6 concentration levels and validation (5 concentration levels sets were prepared from commercial Dalia Cheese from different manufacturers by spiking it with palm oil at concentrations ranging 2-50 % and 5-40 %, respectively. Fifteen Dalia Cheese were evaluated as external set. The spectra of each sample, after homogenization, were acquired in triplicate using a FTIR Shimatsu Prestige 21 Spectrophotometer, with a horizontal diamond ATR accessory in the MIR region 4000-600 cm-1. Statistical methods as PLS were applied using MVC1 routines written for Matlab R2010a. As first step the optimal condition for PLS model were obtained using cross-validation on the Calibration set. Spectral region in 3873-652 cm-1, and 3 PLS-factors were stated as the best conditions and showed an R2 value of 0.9338 and a relative error in the calibration of 17.2%. Then validation set was evaluated, obtaining good recovery rates (108% and acceptable dispersion of the data (20%. The curve of actual vs. predicted values shows slope near to 1 and origin close to 0, with an R2 of 0.9695. When the external sample set was evaluated, samples F19, F21, F22 and F24, showed detectable levels of palm fats. The results proved that FTIR-PLS is a reliable non-destructive technique for a rapid quantification the level of adulteration in cheese.  The spectroscopic methods could assist the quality control authority, traders and the producers to discriminate the adulterated cheeses with palm oil.

  1. Energy transfer dynamics in trimers and aggregates of light-harvesting complex II probed by 2D electronic spectroscopy

    International Nuclear Information System (INIS)

    The pathways and dynamics of excitation energy transfer between the chlorophyll (Chl) domains in solubilized trimeric and aggregated light-harvesting complex II (LHCII) are examined using two-dimensional electronic spectroscopy (2DES). The LHCII trimers and aggregates exhibit the unquenched and quenched excitonic states of Chl a, respectively. 2DES allows direct correlation of excitation and emission energies of coupled states over population time delays, hence enabling mapping of the energy flow between Chls. By the excitation of the entire Chl b Qy band, energy transfer from Chl b to Chl a states is monitored in the LHCII trimers and aggregates. Global analysis of the two-dimensional (2D) spectra reveals that energy transfer from Chl b to Chl a occurs on fast and slow time scales of 240–270 fs and 2.8 ps for both forms of LHCII. 2D decay-associated spectra resulting from the global analysis identify the correlation between Chl states involved in the energy transfer and decay at a given lifetime. The contribution of singlet–singlet annihilation on the kinetics of Chl energy transfer and decay is also modelled and discussed. The results show a marked change in the energy transfer kinetics in the time range of a few picoseconds. Owing to slow energy equilibration processes, long-lived intermediate Chl a states are present in solubilized trimers, while in aggregates, the population decay of these excited states is significantly accelerated, suggesting that, overall, the energy transfer within the LHCII complexes is faster in the aggregated state

  2. Energy transfer dynamics in trimers and aggregates of light-harvesting complex II probed by 2D electronic spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Enriquez, Miriam M.; Zhang, Cheng; Tan, Howe-Siang, E-mail: howesiang@ntu.edu.sg [Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371 (Singapore); Akhtar, Parveen; Garab, Győző; Lambrev, Petar H., E-mail: lambrev@brc.hu [Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, P.O. Box 521, H-6701 Szeged (Hungary)

    2015-06-07

    The pathways and dynamics of excitation energy transfer between the chlorophyll (Chl) domains in solubilized trimeric and aggregated light-harvesting complex II (LHCII) are examined using two-dimensional electronic spectroscopy (2DES). The LHCII trimers and aggregates exhibit the unquenched and quenched excitonic states of Chl a, respectively. 2DES allows direct correlation of excitation and emission energies of coupled states over population time delays, hence enabling mapping of the energy flow between Chls. By the excitation of the entire Chl b Q{sub y} band, energy transfer from Chl b to Chl a states is monitored in the LHCII trimers and aggregates. Global analysis of the two-dimensional (2D) spectra reveals that energy transfer from Chl b to Chl a occurs on fast and slow time scales of 240–270 fs and 2.8 ps for both forms of LHCII. 2D decay-associated spectra resulting from the global analysis identify the correlation between Chl states involved in the energy transfer and decay at a given lifetime. The contribution of singlet–singlet annihilation on the kinetics of Chl energy transfer and decay is also modelled and discussed. The results show a marked change in the energy transfer kinetics in the time range of a few picoseconds. Owing to slow energy equilibration processes, long-lived intermediate Chl a states are present in solubilized trimers, while in aggregates, the population decay of these excited states is significantly accelerated, suggesting that, overall, the energy transfer within the LHCII complexes is faster in the aggregated state.

  3. Analysis of NMR spectra of sugar chains of glycolipids by multiple relayed COSY and 2D homonuclear Hartman-Hahn spectroscopy

    International Nuclear Information System (INIS)

    The authors applied multiple relayed COSY and 2D homonuclear Hartman-Hahn spectroscopy to globoside, a glycolipid purified from human red blood cells. The subspectra corresponding to individual sugar components were extracted even from overlapping proton resonances by taking the cross sections of 2D spectra parallel to the F2 axis at anomeric proton resonances, so that unambiguous assignments of sugar proton resonances were accomplished. (Auth.)

  4. Investigation of Catalytic NOx, reduction with transient techniques, isotopic exchange and FT-IR spectroscopy

    International Nuclear Information System (INIS)

    Emissions from vehicles are suppressed by catalytic conversion, i.e. total oxidation of carbon monoxide and hydrocarbons and reduction of nitrogen oxides. The on-going demand for lower emissions requires more detailed knowledge about the catalytic reaction mechanisms and kinetics on the level of elementary steps, especially because of the mutual interactions in the complex reaction mixture. The reaction mechanisms for the abatement of nitrogen oxides (NOx) are of particular interest, since they are environmentally very unfriendly compounds. Transient experimental techniques can be used as a tool to understand the reaction mechanisms and to develop mathematical models allowing simulation and optimisation of the behaviour of three-way catalyst converters. In chemical kinetics, isotope-labelled reactants are frequently employed to follow reaction pathways and to determine reaction mechanisms. The kinetics and mechanisms of the catalytic reduction of nitrogen oxide (NO) by hydrogen as well as self-decomposition of NO and N2O were studied over alumina based palladium and rhodium-alumina monoliths. In addition, NO reduction with H2 and D2, isotope exchange of hydrogen atoms in water, ammonia and hydrogen with deuterium, as well as adsorption of ammonia and water on the Pd-monolith were studied with transient experiments. Transient step-response experiments, isotopic jumping techniques, steady- state isotopic-transient analysis, temperature programmed desorption (TPD) and Fourier-transformed infrared spectroscopy (FT-IR) were used as experimental techniques. The catalysts were characterised by carbon monoxide chemisorption, nitrogen physisorption and X-ray photoelectron spectroscopy (XPS). Nitrogen, nitrous oxide, ammonia, and water were detected as reaction products in NO reduction by hydrogen. The transient and FT-IR experiments yielded information about the surface reaction mechanisms. The dissociation of NO on the catalyst surface is the crucial step, dominating the

  5. Monitoring lipase-catalyzed interesterification for bulky fats modification with FT-IR/NIR spectroscopy

    DEFF Research Database (Denmark)

    Chang, Tinghong; Lai, Xuxin; Zhang, Hong;

    2005-01-01

    least squares (PLS) regression. High correlations (r > 0.96) were obtained from cross validations of the data estimated by FT-IR, FT-NIRand above-mentioned conventional analytical methods, except for correlations (r = 0.90-0,95) between FT-IR and SFC profiles. Overall, FT-NIR spectroscopy coupled with...... transmission mode measured at 70 °C had the highest correlations which also had the most close conditions to the sampled products in the process, indicating a big potential to implement as online control for monitoring enzymatic interesterification process....

  6. Analyzing 2D THz-Raman spectroscopy using a non-Markovian Brownian oscillator model with nonlinear system-bath interactions

    CERN Document Server

    Ikeda, Tatsushi; Tanimura, Yoshitaka

    2015-01-01

    We explore and describe the roles of inter-molecular vibrations in terms of a Brownian oscillator (BO) model with linear-linear (LL) and square-linear (SL) system-bath interactions, which we use to analyze two-dimensional (2D) THz-Raman spectra obtained by means of molecular dynamics (MD) simulations. In addition to linear absorption (1D IR), we calculate 2D Raman-THz-THz, THz-Raman-THz, and THz-THz-Raman signals for liquid formamide, water, and methanol using an equilibrium non-equilibrium hybrid MD simulation. The calculated 1D IR and 2D THz-Raman signals are then accounted by the LL+SL BO model with the use of the hierarchal Fokker-Planck equations for a non-perturbative and non-Markovian noise. All of the characteristic 2D profiles of the simulated signals are reproduced using the LL+SL BO model, indicating that the present model captures the essential features of the inter-molecular motion. We analyze the fitted the 2D profiles in terms of anharmonicity, nonlinear polarizability, and dephasing time. The ...

  7. Analysis of 2D THz-Raman spectroscopy using a non-Markovian Brownian oscillator model with nonlinear system-bath interactions.

    Science.gov (United States)

    Ikeda, Tatsushi; Ito, Hironobu; Tanimura, Yoshitaka

    2015-06-01

    We explore and describe the roles of inter-molecular vibrations employing a Brownian oscillator (BO) model with linear-linear (LL) and square-linear (SL) system-bath interactions, which we use to analyze two-dimensional (2D) THz-Raman spectra obtained by means of molecular dynamics (MD) simulations. In addition to linear infrared absorption (1D IR), we calculated 2D Raman-THz-THz, THz-Raman-THz, and THz-THz-Raman signals for liquid formamide, water, and methanol using an equilibrium non-equilibrium hybrid MD simulation. The calculated 1D IR and 2D THz-Raman signals are compared with results obtained from the LL+SL BO model applied through use of hierarchal Fokker-Planck equations with non-perturbative and non-Markovian noise. We find that all of the qualitative features of the 2D profiles of the signals obtained from the MD simulations are reproduced with the LL+SL BO model, indicating that this model captures the essential features of the inter-molecular motion. We analyze the fitted 2D profiles in terms of anharmonicity, nonlinear polarizability, and dephasing time. The origins of the echo peaks of the librational motion and the elongated peaks parallel to the probe direction are elucidated using optical Liouville paths. PMID:26049441

  8. High resolution spectroscopy of the Cs2 D 1Sigma u + -X 1Sigma g + transition and hyperfine structure

    Science.gov (United States)

    Kobayashi, Tooru; Usui, Takashi; Kumauchi, Takahiro; Baba, Masaaki; Ishikawa, Kiyoshi; Katô, Hajime

    1993-02-01

    The Doppler-free high resolution laser spectroscopy of Cs2 D 1Σu+-X 1Σg+ transition is extended up to v'=65. By comparing the spectral linewidth and the time-resolved fluorescence intensity, the line broadening observed for transitions to the D 1Σu+(v'=63,J'≤70) levels is identified as the lifetime broadening originating from the predissociation. Line splittings are observed for the D 1Σu+(v'=46,J'≥95)-X 1Σg+(v`= 1,J`) transitions and are identified as the hyperfine splitting due to a magnetic dipole interaction between nuclear spin and electron. The hyperfine splitting is attributed to mixing of the (2) 3Πu state, whose wave function changes from Hund's case (a) to case (b) at large J. The dependence of the electric dipole transition moment on the internuclear distance for the D 1Σu+-X 1Σg+ transition is determined by comparing the observed and calculated line intensities of the dispersed fluorescence.

  9. Detection of metanil yellow contamination in turmeric using FT-Raman and FT-IR spectroscopy

    Science.gov (United States)

    Dhakal, Sagar; Chao, Kuanglin; Qin, Jianwei; Kim, Moon; Schmidt, Walter; Chan, Dian

    2016-05-01

    Turmeric is well known for its medicinal value and is often used in Asian cuisine. Economically motivated contamination of turmeric by chemicals such as metanil yellow has been repeatedly reported. Although traditional technologies can detect such contaminants in food, high operational costs and operational complexities have limited their use to the laboratory. This study used Fourier Transform Raman Spectroscopy (FT-Raman) and Fourier Transform - Infrared Spectroscopy (FT-IR) to identify metanil yellow contamination in turmeric powder. Mixtures of metanil yellow in turmeric were prepared at concentrations of 30%, 25%, 20%, 15%, 10%, 5%, 1% and 0.01% (w/w). The FT-Raman and FT-IR spectral signal of pure turmeric powder, pure metanil yellow powder and the 8 sample mixtures were obtained and analyzed independently to identify metanil yellow contamination in turmeric. The results show that FT-Raman spectroscopy and FT-IR spectroscopy can detect metanil yellow mixed with turmeric at concentrations as low as 1% and 5%, respectively, and may be useful for non-destructive detection of adulterated turmeric powder.

  10. Rapid detection of talcum powder in tea using FT-IR spectroscopy coupled with chemometrics.

    Science.gov (United States)

    Li, Xiaoli; Zhang, Yuying; He, Yong

    2016-01-01

    This paper investigated the feasibility of Fourier transform infrared transmission (FT-IR) spectroscopy to detect talcum powder illegally added in tea based on chemometric methods. Firstly, 210 samples of tea powder with 13 dose levels of talcum powder were prepared for FT-IR spectra acquirement. In order to highlight the slight variations in FT-IR spectra, smoothing, normalize and standard normal variate (SNV) were employed to preprocess the raw spectra. Among them, SNV preprocessing had the best performance with high correlation of prediction (RP = 0.948) and low root mean square error of prediction (RMSEP = 0.108) of partial least squares (PLS) model. Then 18 characteristic wavenumbers were selected based on a hybrid of backward interval partial least squares (biPLS) regression, competitive adaptive reweighted sampling (CARS) algorithm and successive projections algorithm (SPA). These characteristic wavenumbers only accounted for 0.64% of the full wavenumbers. Following that, 18 characteristic wavenumbers were used to build linear and nonlinear determination models by PLS regression and extreme learning machine (ELM), respectively. The optimal model with RP = 0.963 and RMSEP = 0.137 was achieved by ELM algorithm. These results demonstrated that FT-IR spectroscopy with chemometrics could be used successfully to detect talcum powder in tea. PMID:27468701

  11. DME Dissociation Reaction on Platinum Electrode Surface : A Quantitative Kinetic Analysis by In Situ IR Spectroscopy

    OpenAIRE

    Zhang, Yi; Tong, Yujin; Lu, Leilei; Osawa, Masatoshi; Ye, Shen

    2010-01-01

    The kinetics of electrocatalytic dissociation reaction of dimethyl ether (DME) on a platinum (Pt) polycrystalline electrode in an acidic solution yielding carbon monoxide (CO) has been quantitatively analyzed by in situ IR spectroscopy in the potential region between 100 and 500 mV (vs reversible hydrogen electrode). A two-step consecutive reaction model, an initial dehydrogenation step followed by a CO formation step, is proposed for the dissociation process of the DME molecule. The mechanis...

  12. Breath air measurement using wide-band frequency tuning IR laser photo-acoustic spectroscopy

    Science.gov (United States)

    Kistenev, Yury V.; Borisov, Alexey V.; Kuzmin, Dmitry A.; Bulanova, Anna A.; Boyko, Andrey A.; Kostyukova, Nadezhda Y.; Karapuzikov, Alexey A.

    2016-03-01

    The results of measuring of biomarkers in breath air of patients with broncho-pulmonary diseases using wide-band frequency tuning IR laser photo-acoustic spectroscopy and the methods of data mining are presented. We will discuss experimental equipment and various methods of intellectual analysis of the experimental spectra in context of above task. The work was carried out with partial financial support of the FCPIR contract No 14.578.21.0082 (ID RFMEFI57814X0082).

  13. Potential of mid IR spectroscopy in the rapid label free identification of skin malignancies

    Science.gov (United States)

    Kastl, Lena; Kemper, Björn; Lloyd, Gavin R.; Nallala, Jayakrupakar; Stone, Nick; Naranjo, Valery; Penaranda, Francisco; Schnekenburger, Jürgen

    2016-03-01

    The rapid inspection of suspicious skin lesions for pathological cell types is the objective of optical point of care diagnostics technologies. A marker free fast diagnosis of skin malignancies would overcome the limitations of the current gold standard surgical biopsy. The time consuming and costly biopsy procedure requires the inspection of each sample by a trained pathologist, which limits the analysis of potentially malignant lesions. Optical technologies like RAMAN or infrared spectroscopy, which provide both, localization and chemical information, can be used to differentiate malignant from healthy tissue by the analysis of multi cell structures and cell type specific spectra. We here report the application of midIR spectroscopy towards fast and reliable skin diagnostics. Within the European research project MINERVA we developed standardized in vitro skin systems with increasing complexity, from single skin cell types as fibroblasts, keratinocytes and melanoma cells, to mixtures of these and finally three dimensional human skin equivalents. The standards were characterized in the established midIR range and also with newly developed systems for fast imaging up to 12 μm. The analysis of the spectra by novel data processing algorithms demonstrated the clear separation of all cell types, especially the tumor cells. The signals from single cell layers were sufficient for cell type differentiation. We have compared different midIR systems and found all of them suitable for specific cell type identification. Our data demonstrate the potential of midIR spectroscopy for fast image acquisition and an improved data processing as sensitive and specific optical biopsy technology.

  14. Mid-IR fiber-optic reflectance spectroscopy for identifying the finish on wooden furniture.

    Science.gov (United States)

    Poli, T; Chiantore, O; Nervo, M; Piccirillo, A

    2011-05-01

    Mid-IR fiber-optic reflectance spectroscopy (FORS) is a totally noninvasive infrared analytical technique allowing the investigation of artworks without the need for any sampling. The development and optimization of this analytical methodology can provide a tool that is capable of supporting conservators during the first steps of their interventions, yielding fast results and dramatically reducing the number of samples needed to identify the materials involved. Furthermore, since reflection IR spectra suffer from important spectral anomalies that complicate accurate spectral interpretation, it is important to characterize known reference materials and substrates in advance. This work aims to verify the possibility of investigating and identifying the most widely used wood finishes by means of fiber-optic (chalcogenide and metal halides) mid-infrared spectroscopy. Two historically widely employed wood finishes (beeswax, shellac) and two modern ones (a hydrogenated hydrocarbon resin and a microcrystalline wax) were investigated in an extended IR range (from 1000 to 6000 cm(-1)) with reflectance spectroscopy and with FORS. The broad spectral response of the MCT detector was exploited in order to include overtones and combination bands from the NIR spectral range in the investigation. The reflectance spectra were compared with those collected in transmission mode in order to highlight modifications to shapes and intensities, to assign absorptions, and finally to select "marker" bands indicating the presence of certain finishing materials, even when applied onto a substrate such as wood, which shows many absorptions in the mid-infrared region. After the characterization, the different products were applied to samples of aged pear wood and investigated with the same techniques in order to check the ability of mid-IR FORS to reveal the presence and composition of the product on the wooden substrate.

  15. UV–UV hole burning and IR dip spectroscopy of homophenylalanine by laser desorption supersonic jet technique

    Energy Technology Data Exchange (ETDEWEB)

    Sohn, Woon Yong; Ishiuchi, Shun-ichi [Chemical Resources Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503 (Japan); Çarçabal, Pierre [Institut des Sciences Moléculaires d’Orsay, CNRS, Université Paris Sud XI, Bâtiment 210, 91405 Orsay (France); Oba, Hikari [Chemical Resources Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503 (Japan); Fujii, Masaaki, E-mail: mfujii@res.titech.ac.jp [Chemical Resources Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503 (Japan)

    2014-12-05

    Highlights: • Homophenylalanine was measured by laser desorption supersonic jet spectroscopy. • Ten conformers were found by UV–UV hole burning spectroscopy. • The observed conformers were assigned by the combination of UV and IR spectra. • Franck–Condon simulations were employed to assign the flexible molecule. - Abstract: Conformer selected electronic and vibrational spectra of homophenylalanine, phenylalanine analogue molecule, were measured by UV–UV hole burning and IR dip spectroscopy combined with laser desorption technique. 10 conformers were found by UV–UV hole burning spectroscopy and their structures were assigned by IR dip and UV absorption spectra with aid of quantum chemical calculations in both S{sub 0} and S{sub 1}. This study shows that the combination of simulated IR and UV spectra is powerful to assign flexible molecules.

  16. Weak carbonyl-methyl intermolecular interactions in acetone clusters explored by IR plus VUV spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Guan, Jiwen [MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631 (China); Hu, Yongjun, E-mail: yjhu@scnu.edu.cn [MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631 (China); Xie, Min [MOE Key Laboratory of Laser Life Science and Institute of Laser Life Science, College of Biophotonics, South China Normal University, Guangzhou 510631 (China); Bernstein, Elliot R. [Department of Chemistry, Colorado State University, Fort Collins, CO 80523-1872 (United States)

    2012-09-11

    Highlights: Black-Right-Pointing-Pointer The carbonyl overtone of acetone clusters is observed by IR-VUV spectroscopy. Black-Right-Pointing-Pointer Acetone molecules in the dimer are stacked with an antiparallel way. Black-Right-Pointing-Pointer The structure of the acetone trimer and the tetramer are the cyclic structures. Black-Right-Pointing-Pointer The carbonyl groups would interact with the methyl groups in acetone clusters. Black-Right-Pointing-Pointer These weak interactions are further confirmed by H/D substitution experiment. -- Abstract: Size-selected IR-VUV spectroscopy is employed to detect vibrational characteristics in the region 2850 {approx} 3550 cm{sup -1} of neutral acetone and its clusters (CH{sub 3}COCH{sub 3}){sub n} (n = 1-4). Features around 3440 cm{sup -1} in the spectra of acetone monomer and its clusters are assigned to the carbonyl stretch (CO) overtone. These features red-shift from 3455 to 3433 cm{sup -1} as the size of the clusters increases from the monomer to the tetramer. Based on calculations, the experimental IR spectra in the C=O overtone region suggest that the dominant structures for the acetone trimer and tetramer should be cyclic in the supersonic expansion sample. This study also suggests that the carbonyl groups interact with the methyl groups in the acetone clusters. These weak interactions are further confirmed by the use of deuterium substitution.

  17. Tunable diode and fibre laser spectroscopy in the near-IR for measurement of gas parameters

    Science.gov (United States)

    Stewart, George; Johnstone, Walter; Arsad, Norhana; Duffin, Kevin

    2008-04-01

    There has been much research performed in recent years on tunable diode laser spectroscopy for detection of gases such as methane, carbon dioxide, acetylene, etc., which possess near-IR absorption lines. To attain adequate sensitivity with weak near-IR lines, wavelength modulation spectroscopy with phase-sensitive detection is normally employed. However injection current modulation of diode lasers produces both wavelength and amplitude modulation, with a phase shift dependent on the modulation frequency. This results in residual amplitude modulation on the output and in distortion of the harmonic signals derived from the absorption line. These are important issues for calibration and where it is desired to accurately recover the line-shape function in order to make simultaneous measurements of gas concentration, pressure or temperature in industrial applications. Here we discuss how calibration-free measurements may be obtained with diode lasers and explore the implications for fibre laser based systems for spectroscopy which conventionally employ thermal or piezoelectric tuning of the wavelength. In particular, we consider modulation techniques which may be applied to ring fibre lasers which use un-pumped erbium fibre as a saturable absorber to prevent mode-hopping or to DFB fibre lasers which use a short cavity with a Bragg grating to ensure single mode operation.

  18. FT-IR and FT-NIR Raman spectroscopy in biomedical research

    Science.gov (United States)

    Naumann, D.

    1998-06-01

    FT-IR and FT-NIR Raman spectra of intact microbial, plant animal or human cells, tissues, and body fluids are highly specific, fingerprint-like signatures which can be used to discriminate between diverse microbial species and strains, characterize growth-dependent phenomena and cell-drug interactions, and differentiate between various disease states. The spectral information potentially useful for biomedical characterizations may be distributed over the entire infrared region of the electromagnetic spectrum, i.e. over the near-, mid-, and far-infrared. It is therefore a key problem how the characteristic vibrational spectroscopic information can be systematically extracted from the infrared spectra of complex biological samples. In this report these questions are addressed by applying factor and cluster analysis treating the classification problem of microbial infrared spectra as a model task. Particularly interesting applications arise by means of a light microscope coupled to the FT-IR spectrometer. FT-IR spectra of single microcolonies of less than 40 μm in diameter can be obtained from colony replica applying a stamping technique that transfers the different, spatially separated microcolonies from the culture plate to a special IR-sample holder. Using a computer controlled x,y-stage together with mapping and video techniques, the fundamental tasks of microbiological analysis, namely detection, enumeration, and differentiation of micro-organisms can be integrated in one single apparatus. Since high quality, essentially fluorescence free Raman spectra may now be obtained in relatively short time intervals on previously intractable biological specimens, FT-IR and NIR-FT-Raman spectroscopy can be used in tandem to characterize biological samples. This approach seems to open up new horizons for biomedical characterizations of complex biological systems.

  19. Using FT-IR Spectroscopy to Elucidate the Structures of Ablative Polymers

    Science.gov (United States)

    Fan, Wendy

    2011-01-01

    The composition and structure of an ablative polymer has a multifaceted influence on its thermal, mechanical and ablative properties. Understanding the molecular level information is critical to the optimization of material performance because it helps to establish correlations with the macroscopic properties of the material, the so-called structure-property relationship. Moreover, accurate information of molecular structures is also essential to predict the thermal decomposition pathways as well as to identify decomposition species that are fundamentally important to modeling work. In this presentation, I will describe the use of infrared transmission spectroscopy (FT-IR) as a convenient tool to aid the discovery and development of thermal protection system materials.

  20. An add-on system for photochemical ATR-IR spectroscopy studies

    DEFF Research Database (Denmark)

    2014-01-01

    The invention relates to an add-on system for a unit mainly adapted for attenuated total reflectance infrared (ATR-IR) spectroscopy. The add-on system enables time-resolved in-situ measurements of different sample types in an easy, simple and inexpensive way. The add-on system includes a cap (300G......) and the cap (300B,300H,300J), a source of light, e.g. a light emitting diode (418) or an optical fibre (416) connectable to a laser, and a light source containing cavity....

  1. Pharmacologic application of fourier transform IR spectroscopy: in vivo toxicity of carbon tetrachloride on rat liver.

    Science.gov (United States)

    Melin, A M; Perromat, A; Déléris, G

    2000-01-01

    Microsomal fractions from rat liver were examined by means of Fourier transform IR (FTIR) spectroscopy to study the in vivo toxic effect of carbon tetrachloride administered by intraperitoneal injection. Lipid content was significantly enhanced in the liver of treated rats compared with untreated ones. The level of saturated fatty acids largely increased while that of unsaturated acids slightly decreased as a consequence of lipid peroxidation induced by the xenobiotic compound. The conformational structure of membrane proteins was changed, which was shown by the large decrease in the alpha-helical configuration. In the polysaccharide region we observed an important loss in glucidic structures that could be related to the metabolic changes caused by carbon tetrachloride intoxication. Thus, FTIR spectroscopy appears to be a useful tool to rapidly investigate the chemical alterations induced by this drug in liver microsomes and to correlate them with biochemical and physiological data.

  2. Interaction of mineral surfaces with simple organic molecules by diffuse reflectance IR spectroscopy (DRIFT)

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Joan E.; Kelley, Michael J.

    2008-06-01

    Diffuse reflectance Fourier-transform infrared spectroscopy (DRIFTS) was used to characterize multi-layers of lysine, glutamic acid and salicylic acid on -alumina and kaolinite surfaces. The results agreed well with those previously obtained by ATR-IR in aqueous media where available, indicating that DRIFT may be regarded as effectively an in-situ spectroscopy for these materials. In the case of salicylic acid adsorption onto γ-alumina, DRIFTS was used to identify monolayer coverage and to detect molecules down to coverage of 3% of a monolayer. The spectroscopic results as to coverage were confirmed by analysis of the solutions used for treatment. The spectra obtained allowed identification of changes in the bonding environment with increasing surface coverage. DRIFTS, offers several advantages in terms of materials, experimental technique and data treatment, motivating further investigations.

  3. Identification of authentic and adulterated Aquilariae Lignum Resinatum by Fourier transform infrared (FT-IR) spectroscopy and two-dimensional correlation analysis

    Science.gov (United States)

    Qu, Lei; Chen, Jian-bo; Zhou, Qun; Zhang, Gui-jun; Sun, Su-qin; Guo, Yi-zhen

    2016-11-01

    As a kind of expensive perfume and valuable herb, the commercial Aquilariae Lignum Resinatum (ALR) is often adulterated for economic motivations. In this research, Fourier transform infrared (FT-IR) spectroscopy and two-dimensional (2D) correlation analysis are employed to establish a simple and quick identification method for the authentic and adulterated ALR. In the conventional infrared spectra, the standard ALR has a strong peak at 1658 cm-1 referring to the conjugated carbonyl of resin, while this peak is absent in the adulterated samples. The position, intensity, and shape of the auto-peaks and cross-peaks of the authentic and adulterated ALR are much different in the synchronous 2D correlation spectra with thermal perturbation. In the range of 1700-1500 cm-1, the standard ALR has four obvious auto-peaks, while the strongest one is at 1659 cm-1. The adulterated sample w-1 has three obvious auto-peaks and the strongest one is at 1647 cm-1. The adulterated sample w-2 has three obvious auto-peaks and the strongest one is at 1519 cm-1. The adulterated sample w-3 has four obvious auto-peaks and the strongest one is at 1690 cm-1. The above auto-peaks confirm that the standard ALR contains a certain content of resin compounds, while the three counterfeits contain little or different resins. The results show the potential of FT-IR spectroscopy and 2D correlation analysis in the simple and quick identification of authentic and adulterated ALR.

  4. Cyclohexene Photo-oxidation over Vanadia Catalyst Analyzed by Time Resolved ATR-FT-IR Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Frei, Heinz; Mul, Guido; Wasylenko, Walter; Hamdy, M. Sameh; Frei, Heinz

    2008-06-04

    Vanadia was incorporated in the 3-dimensional mesoporous material TUD-1 with a loading of 2percent w/w vanadia. The performance in the selective photo-oxidation of liquid cyclohexene was investigated using ATR-FT-IR spectroscopy. Under continuous illumination at 458 nm a significant amount of product, i.e. cyclohexenone, was identified. This demonstrates for the first time that hydroxylated vanadia centers in mesoporous materials can be activated by visible light to induce oxidation reactions. Using the rapid scan method, a strong perturbation of the vanadyl environment could be observed in the selective oxidation process induced by a 458 nm laser pulse of 480 ms duration. This is proposed to be caused by interaction of the catalytic centre with a cyclohexenyl hydroperoxide intermediate. The restoration of the vanadyl environment could be kinetically correlated to the rate of formation of cyclohexenone, and is explained by molecular rearrangement and dissociation of the peroxide to ketone and water. The ketone diffuses away from the active center and ATR infrared probing zone, resulting in a decreasing ketone signal on the tens of seconds time scale after initiation of the photoreaction. This study demonstrates the high potential of time resolved ATR FT-IR spectroscopy for mechanistic studies of liquid phase reactions by monitoring not only intermediates and products, but by correlating the temporal behavior of these species to molecular changes of the vanadyl catalytic site.

  5. Determination of leachate compounds relevant for landfill aftercare using FT-IR spectroscopy.

    Science.gov (United States)

    Lenz, Sabine; Böhm, Katharina; Ottner, Reinhold; Huber-Humer, Marion

    2016-09-01

    Controlling and monitoring of emissions from municipal solid waste (MSW) landfills is important to reduce environmental damage and health risks. Therefore, simple and meaningful monitoring tools are required. This paper presents how Fourier Transform Infrared (FT-IR) Spectroscopy can be used to monitor leachate from various landfill sites. The composition of percolated leachate provides information about reactivity or stability of organic matter in landfills. Chemical compounds of investigated leachate are depicted by distinct spectral pattern. Partial least squares regression (PLS-R) models, a multivariate analysis tool, were developed based on infrared spectra to determine simultaneously conventional parameters such as ammonium, nitrate, sulfate, and dissolved organic carbon. The developed models are appropriate for application in waste management practice with respect to their excellent coefficients of determination, namely R(2)=0.99, 0.99, 0.98, and 0.98, their low errors of cross-validation and their high ratios of performance to deviation (RPD=9.3, 12.5, 6.5, 7.3). Thus, FT-IR spectroscopy turned out to be a reliable, time-saving tool to determine four parameters relevant for landfill aftercare monitoring by one single easy adaptable measurement. PMID:26951718

  6. New ultrarapid-scanning interferometer for FT-IR spectroscopy with microsecond time-resolution

    Science.gov (United States)

    Süss, B.; Ringleb, F.; Heberle, J.

    2016-06-01

    A novel Fourier-transform infrared (FT-IR) rapid-scan spectrometer has been developed (patent pending EP14194520.4) which yields 1000 times higher time resolution as compared to conventional rapid-scanning spectrometers. The central element to achieve faster scanning rates is based on a sonotrode whose front face represents the movable mirror of the interferometer. A prototype spectrometer with a time resolution of 13 μs was realized, capable of fully automated long-term measurements with a flow cell for liquid samples, here a photosynthetic membrane protein in solution. The performance of this novel spectrometer is demonstrated by recording the photoreaction of bacteriorhodopsin initiated by a short laser pulse that is synchronized to the data recording. The resulting data are critically compared to those obtained by step-scan spectroscopy and demonstrate the relevance of performing experiments on proteins in solution. The spectrometer allows for future investigations of fast, non-repetitive processes, whose investigation is challenging to step-scan FT-IR spectroscopy.

  7. Evaluation of Polymerization Efficacy in Composite Resins via FT-IR Spectroscopy and Vickers Microhardness Test.

    Science.gov (United States)

    Jafarzadeh, Tahereh-Sadat; Erfan, Mohammad; Behroozibakhsh, Marjan; Fatemi, Mostafa; Masaeli, Reza; Rezaei, Yashar; Bagheri, Hossein; Erfan, Yasaman

    2015-01-01

    Background and aims. Polymerization efficacy affects the properties and performance of composite resin restorations.The purpose of this study was to evaluate the effectiveness of polymerization of two micro-hybrid, two nano-hybrid and one nano-filled ormocer-based composite resins, cured by two different light-curing systems, using Fourier transformation infrared (FT-IR) spectroscopy and Vickers microhardness testing at two different depths (top surface, 2 mm). Materials and methods. For FT-IR spectrometry, five cylindrical specimens (5mm in diameter × 2 mm in length) were prepared from each composite resin using Teflon molds and polymerized for 20 seconds. Then, 70-μm wafers were sectioned at the top surface and at2mm from the top surface. The degree of conversion for each sample was calculated using FT-IR spectroscopy. For Vickers micro-hardness testing, three cylindrical specimens were prepared from each composite resin and polymerized for 20 seconds. The Vickers microhardness test (Shimadzu, Type M, Japan) was performed at the top and bottom (depth=2 mm) surfaces of each specimen. Three-way ANOVA with independent variables and Tukey tests were performed at 95% significance level. Results. No significant differences were detected in degree of conversion and microhardness between LED and QTH light-curing units except for the ormocer-based specimen, CeramX, which exhibited significantly higher DC by LED. All the composite resins showed a significantly higher degree of conversion at the surface. Microhardness was not significantly affected by depth, except for Herculite XRV Ultra and CeramX, which showed higher values at the surface. Conclusion. Composite resins containing nano-particles generally exhibited more variations in degree of conversion and microhardness. PMID:26889359

  8. Effect of Water on HEMA Conversion by FT-IR Spectroscopy

    Directory of Open Access Journals (Sweden)

    TS. Jafarzadeh Kashi

    2007-09-01

    Full Text Available Objective: The use of HEMA as a biocompatible material in dentin bonding systems and its potential for clinical applications has been well established. Excess water can affect conversion of bonding resins. The aim of this study was to survey the effect of water on the degree of conversion of HEMA by Fourier Transform Infra-red Spectroscopy (FT-IR.Materials and Methods: In this experimental study, distilled water was added in amounts of 0, 0.05, 0.1, 0.2, and 0.4 ml to 1 ml of curable HEMA solution. Six repetitions per wa-ter ratio were made and investigated. Each sample was polymerized for 60 seconds. De-gree of conversion was obtained from the absorbance IR-Spectrum of the materials before and after polymerization by FT-IR spectroscopy. One way ANOVA and Tukey-HSD were carried out to compare and detect any differences among groups.Results: Statistical analysis indicates highly significant difference between pairs of groups at level (P<0.001. The results showed a trend of decreasing in HEMA conversion with increasing water. Degree of conversion changes significantly within the 0.05 ml to 0.2 ml water range. However, degree of conversion did not change after reaching 0.02 ml and before 0.05.Conclusion: Degree of conversion of HEMA decreased by increasing water. The most dramatic effect of water on the polymerization process occurs within a range which exists under clinical conditions. The reason that the degree of conversion did not show signifi-cant result before 0.05 ml may be related to the hydrophilic nature of HEMA.

  9. Near-IR spectroscopy of the highly inflated, hottest known Jupiter KOI-13.01

    Science.gov (United States)

    Zhao, Ming

    2013-10-01

    We propose to use the WFC3 IR-G141 grism to measure the near-IR dayside emission spectrum of the highly inflated, hottest known Jupiter KOI-13.01 via secondary eclipses. The A-type host star of KOI-13.01 has the highest temperature among all known hot Jupiter hosts, producing extreme irradiation and making the planet's atmosphere probably quite different from others'. It is therefore an extreme and unique target to test exoplanetary atmosphere models and observed correlation between thermal inversion and irradiation. The host star of KOI-13.01 has a companion of same brightness and spectral type at 1.2 arcsec. Because the two stars will be well-resolved by WFC3, the stellar companion provides a unique advantage to calibrate the common-mode systematics of the eclipse light curves, enabling high precision and high fidelity spectroscopy of the planet's dayside emission. The WFC3 observations will definitively determine the presence or absence of a thermal inversion in the planet's upper atmosphere by probing the water bands between 1.1 - 1.7 microns. When combined with the Kepler nightside thermal emission measurement in visible light, the near-IR spectroscopy from WFC3 will also help tightly constrain its albedo and heat transport efficiency. Furthermore, resolving the binary and measuring the secondary eclipses will allow us to definitively verify whether the brigher star is indeed the host of the planet. This study can only be done with HST because of the ultra-high precision requisite and the coverage of water bands unavailable from ground.

  10. Drift and transmission FT-IR spectroscopy of forest soils: an approach to determine decomposition processes of forest litter

    International Nuclear Information System (INIS)

    A method is described to characterize organic soil layers using Fourier transformed infrared spectroscopy. The applicability of FT-IR, either dispersive or transmission, to investigate decomposition processes of spruce litter in soil originating from three different forest sites in two climatic regions was studied. Spectral information of transmission and diffuse reflection FT-IR spectra was analyzed and compared. For data evaluation Kubelka Munk (KM) transformation was applied to the DRIFT spectra. Sample preparation for DRIFT is simpler and less time consuming in comparison to transmission FT-IR, which uses KBr pellets. A variety of bands characteristics of molecular structures and functional groups has been identified for these complex samples. Analysis of both transmission FT-IR and DRIFT, showed that the intensity of distinct bands is a measure of the decomposition of forest litter. Interferences due to water adsorption spectra were reduced by DRIFT measurement in comparison to transmission FT-IR spectroscopy. However, data analysis revealed that intensity changes of several bands of DRIFT and transmission FT-IR were significantly correlated with soil horizons. The application of regression models enables identification and differentiation of organic forest soil horizons and allows to determine the decomposition status of soil organic matter in distinct layers. On the basis of the data presented in this study, it may be concluded that FT-IR spectroscopy is a powerful tool for the investigation of decomposition dynamics in forest soils. (author)

  11. An add-on cap for ATR-IR spectroscopy studies

    DEFF Research Database (Denmark)

    2014-01-01

    The invention relates to a cap (300B) for an attenuated total reflectance infrared (ATR-IR) spectrometer, the ATR-IR spectrometer comprising an ATR-IR plate (200). The cap (300B) comprises an ATR- IR plate facing cap surface. When the ATR-IR plate facing cap surface is placed on the sample surfac...

  12. Cold, Gas-Phase UV and IR Spectroscopy of Protonated Leucine Enkephalin and its Analogues

    Science.gov (United States)

    Burke, Nicole L.; Redwine, James; Dean, Jacob C.; McLuckey, Scott A.; Zwier, Timothy S.

    2014-06-01

    The conformational preferences of peptide backbones and the resulting hydrogen bonding patterns provide critical biochemical information regarding the structure-function relationship of peptides and proteins. The spectroscopic study of cryogenically-cooled peptide ions in a mass spectrometer probes these H-bonding arrangements and provides information regarding the influence of a charge site. Leucine enkephalin, a biologically active endogenous opiod peptide, has been extensively studied as a model peptide in mass spectrometry. This talk will present a study of the UV and IR spectroscopy of protonated leucine enkephalin [YGGFL+H]+ and two of its analogues: the sodiated [YGGFL+Na]+ and C-terminally methyl esterified [YGGFL-OMe+H]+ forms. All experiments were performed in a recently completed multi-stage mass spectrometer outfitted with a cryocooled ion trap. Ions are generated via nano-electrospray ionization and the analyte of interest is isolated in a linear ion trap. The analyte ions are trapped in a 22-pole ion trap held at 5 K by a closed cycle helium cryostat and interrogated via UV and IR lasers. Photofragments are trapped and isolated in a second LIT and mass analyzed. Double-resonance UV and IR methods were used to assign the conformation of [YGGFL+H]+, using the NH/OH stretch, Amide I, and Amide II regions of the infrared spectrum. The assigned structure contains a single backbone conformation at vibrational/rotational temperatures of 10 K held together with multiple H-bonds that self-solvate the NH3+ site. A "proton wire" between the N and C termini reinforces the H-bonding activity of the COO-H group to the F-L peptide bond, whose cleavage results in formation of the b4 ion, which is a prevalent, low-energy fragmentation pathway for [YGGFL+H]+. The reinforced H-bonding network in conjunction with the mobile proton theory may help explain the prevalence of the b4 pathway. In order to elucidate structural changes caused by modifying this H-bonding activity

  13. Sensing the Structural Differences in Cellulose from Apple and Bacterial Cell Wall Materials by Raman and FT-IR Spectroscopy

    OpenAIRE

    Artur Zdunek; Monika Szymańska-Chargot; Justyna Cybulska

    2011-01-01

    Raman and Fourier Transform Infrared (FT-IR) spectroscopy was used for assessment of structural differences of celluloses of various origins. Investigated celluloses were: bacterial celluloses cultured in presence of pectin and/or xyloglucan, as well as commercial celluloses and cellulose extracted from apple parenchyma. FT-IR spectra were used to estimate of the Iβ content, whereas Raman spectra were used to evaluate the degree of crystallinity of the cellulose. The crystallinity index (XC R...

  14. A Practical Deconvolution Computation Algorithm to Extract 1D Spectra from 2D Images of Optical Fiber Spectroscopy

    CERN Document Server

    Li, Guangwei; Bai, Zhongrui

    2015-01-01

    Bolton and Schlegel presented a promising deconvolution method to extract 1D spectra from a 2D optical fiber spectral CCD image. The method could eliminate the PSF difference between fibers, extract spectra to the photo noise level, as well as improve the resolution. But the method is limited by its huge computation requirement and thus cannot be implemented in actual data reduction. In this article, we develop a practical computation method to solve the computation problem. The new computation method can deconvolve a 2D fiber spectral image of any size with actual PSFs, which may vary with positions. Our method does not require large amounts of memory and can extract a 4k multi 4k noise-free CCD image with 250 fibers in 2 hr. To make our method more practical, we further consider the influence of noise, which is thought to be an intrinsic illposed problem in deconvolution algorithms. We modify our method with a Tikhonov regularization item to depress the method induced noise. Compared with the results of tra...

  15. Comparing the photophysics of the two forms of the Orange Carotenoid Protein using 2D electronic spectroscopy

    Directory of Open Access Journals (Sweden)

    Mathies R.A.

    2013-03-01

    Full Text Available Broadband two-dimensional electronic spectroscopy is applied to investigate the photophysics of the photoactive orange carotenoid protein, which is involved in nonphotochemical quenching in cyanobacteria. Differences in dynamics between the light and dark forms arise from the different structure of the carotenoid in the protein pocket, with consequences for the biological role of the two forms.

  16. Monitoring wine aging with Fourier transform infrared spectroscopy (FT-IR

    Directory of Open Access Journals (Sweden)

    Basalekou Marianthi

    2015-01-01

    Full Text Available Oak wood has commonly been used in wine aging but recently other wood types such as Acacia and Chestnut, have attracted the interest of the researchers due to their possible positive contribution to wine quality. However, only the use of oak and chestnut woods is approved by the International Enological Codex of the International Organisation of Vine and Wine. In this study Fourier Transform (FT-mid-infrared spectroscopy combined with Discriminant Analysis was used to differentiate wines aged in barrels made from French oak, American oak, Acacia and Chestnut and in tanks with oak chips, over a period of 12 months. Two red (Mandilaria, Kotsifali and two white (Vilana, Dafni native Greek grape varieties where used to produce four wines. The Fourier Transform Infrared (FT-IR spectra of the samples were recorded on a Zinc Selenide (ZnSe window after incubation at 40 °C for 30 min. A complete differentiation of the samples according to both the type of wood used and the contact time was achieved based on their FT-IR spectra.

  17. Synthesis and structure elucidation of a series of pyranochromene chalcones and flavanones using 1D and 2D NMR spectroscopy and X-ray crystallography.

    Science.gov (United States)

    Pawar, Sunayna S; Koorbanally, Neil A

    2014-06-01

    A series of novel pyranochromene chalcones and corresponding flavanones were synthesized. This is the first report on the confirmation of the absolute configuration of chromene-based flavanones using X-ray crystallography. These compounds were characterized by 2D NMR spectroscopy, and their assignments are reported herein. The 3D structure of the chalcone 3b and flavanone 4g was determined by X-ray crystallography, and the structure of the flavanone was confirmed to be in the S configuration at C-2.

  18. Study of the cyclodextrin and its complexation with 2,4-dinitrobenzoic acid through photophysical properties and 2D NMR spectroscopy

    Science.gov (United States)

    Stalin, T.; Srinivasan, K.; Sivakumar, K.

    2014-02-01

    The host-guest inclusion complex formation of 2,4-dinitrobenzoic acid (2,4-DNB) with nano-hydrophobic cavity of β-cyclodextrin (β-CD) in solution phase were studied by UV-visible spectrophotometer and electrochemical method (cyclic voltammetry, CV). The prototropic behaviors of 2,4-DNB with and without β-CD and the ground state acidity constant (pKa) of host-guest inclusion complex (2,4-DNB-β-CD) was studied. The binding constant of the inclusion complex at 303 K was calculated using Benesi-Hildebrand plot. The solid inclusion complex formation between β-CD and 2,4-DNB was confirmed by 1H NMR, 2D 1H NMR (ROESY), FT-IR, XRD and SEM analysis. A schematic representation of this inclusion process is proposed by molecular docking studies using the patch dock server.

  19. Development and testing of an image-guided FT-IR instrument for field spectroscopy

    Science.gov (United States)

    Dai, Xiaobing; Liu, Xiangyan; Liu, Li

    2015-09-01

    Standoff detection, identification and quantification of chemicals require sensitive spectrometers with calibration capabilities. We have developed a compact novel instrument that can not only provide imaging capability, bust also one that provides spectral capability of the field of view (FOV) center under the image-guided. The system employs a Fourier transform infrared (FT-IR) spectrometer, coupled with chalcogenide glass optical fiber, and a specially designed infrared optic lens. A special kit provided by Bruker Optics is connected on the spectrometer to focus the infrared beam from the lens at the entry of the fiber. Its spectral range covers the infrared band from 1850cm-1 to 5000cm-1 and its spectral resolution could be chosen among six selected values 1, 2, 4, 8, 16, 32cm-1. This paper will address the issues of image-guided spectroscopy and will show how an instrument designed for specifically imaging applications can dramatically improve the performance of the system and quality of the data acquired. The benefit of these technologies in spectroscopy can be demonstrated with a system optimally designed for detecting spectral characteristics of moving targets.

  20. Analysis of a Brazilian baroque sculpture using Raman spectroscopy and FT-IR

    Science.gov (United States)

    Freitas, Renato P.; Ribeiro, Iohanna M.; Calza, Cristiane; Oliveira, Ana L.; Felix, Valter S.; Ferreira, Douglas S.; Pimenta, André R.; Pereira, Ronaldo V.; Pereira, Marcelo O.; Lopes, Ricardo T.

    2016-02-01

    In this study, samples were taken from the sculpture of Our Lady of Sorrows and analyzed by Raman spectroscopy and FT-IR. This sculpture has been dated to the early eighteenth century. Samples were also examined using optical microscopy and Energy Dispersive Spectroscopy (EDS). Based on chemical analysis, the pigments vermilion [HgS], massicot [PbO] and azurite [Cu3(CO3)2(OH)2] were found in the sculpture polychrome. The results indicate that the green polychrome of the sculpture's mantle comes from the blending of massicot and azurite. Because the literature reports that the mantle of the Our Lady of Sorrows sculpture is blue, the mixing of these pigments results from a production error. The results also indicate the presence of Au in the sculpture, which indicates the originality of the piece. The results from this study helped restorers to choose the appropriate procedures for intervening in the sculpture and contributed to the knowledge about the manufacturing process of Brazilian baroque sculptures.

  1. Half-sandwich (6-arene)ruthenium(II) chiral Schiff base complexes: Analysis of the diastereomeric mixtures in solution by 2D-NMR spectroscopy

    Indian Academy of Sciences (India)

    Rakesh K Rath; G A Nagana Gowda; Akhil R Chakravarty

    2002-10-01

    2D NMR spectroscopy has been used to determine the metal configuration in solution of three complexes, viz. [($\\eta^6$--cymene)Ru(L∗)Cl] (1) and [(6--cymene)Ru(L∗)(L')] (ClO4) (L' = H2O, 2; PPh3, 3), where L∗ is the anion of ()-(1-phenylethyl)salicylaldimine. The complexes exist in two diastereomeric forms in solution. Both the (Ru, C)- and (Ru, C)-diastereomers display the presence of attractive CH/ interaction involving the phenyl group attached to the chiral carbon and the cymene ring hydrogens. This interaction restricts the rotation of the C∗-N single bond and, as a result, two structural types with either the hydrogen atom attached to the chiral carbon (C∗) or the methyl group attached to C∗ in close proximity of the cymene ring protons get stabilized. Using 2D NMR spectroscopy as a tool, the spatial interaction involving these protons are studied in order to obtain the metal configuration(s) of the diastereomeric complexes in solution. This technique has enabled us to determine the metal configuration as (Ru, C) for the major isomers of 1-3 in solution.

  2. CO Adsorption on Pt Nanoparticles in Low E-Fields Studied by ATR-IR Spectroscopy in a Microreactor

    NARCIS (Netherlands)

    Susarrey Arce, A.; Tiggelaar, R.M.; Gardeniers, J.G.E.; Houselt, van A.; Lefferts, L.

    2015-01-01

    The adsorption of carbon monoxide (CO) on platinum (Pt) nanoparticles under the influence of a low electrical field (E-field) is studied. The adsorption of CO is monitored by attenuated total reflection infrared (ATR-IR) spectroscopy, while an external electrical field is applied over the microreact

  3. Detection and classification of salmonella serotypes using spectral signatures collected by fourier transform infrared (FT-IR) spectroscopy

    Science.gov (United States)

    Spectral signatures of Salmonella serotypes namely Salmonella Typhimurium, Salmonella Enteritidis, Salmonella Infantis, Salmonella Heidelberg and Salmonella Kentucky were collected using Fourier transform infrared spectroscopy (FT-IR). About 5-10 µL of Salmonella suspensions with concentrations of 1...

  4. NMR and IR Spectroscopy for the Structural Characterization of Edible Fats and Oils: An Instrumental Analysis Laboratory

    Science.gov (United States)

    Crowther, Molly W.

    2008-01-01

    This article describes an upper-level instrumental laboratory for undergraduates that explores the complementary nature of IR and NMR spectroscopy for analysis of several edible fats and oils that are structurally similar but differ in physical properties and health implications. Five different fats and oils are analyzed for average chain length,…

  5. Photoinduced FT-IR spectroscopy of conjugated polymer/fullerene composites embedded into conventional host polymer matrices

    OpenAIRE

    Johansson, H; Brabec, C. J.; H. Neugebauer; Kvarnström, C.; J. C. Hummelen; Janssen, R.A.J.; Sariciftci, N.S.

    1999-01-01

    In this work, we report on the investigation of photoexcited states in conjugated polymer (donor) - fullerene (acceptor) interpenetrating networks (polythiophene derivatives - PC61BM) embedded into conventional polymer hosts like polystyrene, polyvinylcarbazole, polycarbonate or polyvinylbenzenechloride, using photoinduced FT-IR spectroscopy. We discuss the influence of specific host polymer matrices on photoexcited states of the photoactive guests via photoinduced infrared activated (IRAV) m...

  6. Molecular orientation of molybdate ions adsorbed on goethite nanoparticles revealed by polarized in situ ATR-IR spectroscopy

    Science.gov (United States)

    Davantès, Athénaïs; Lefèvre, Grégory

    2016-11-01

    The speciation of species adsorbed on nanoparticles is a major concern for several fields, as environmental pollution and remediation, surface functionalization, or catalysis. Attenuated total reflectance infrared spectroscopy (ATR-IR) was amongst the rare methods able to give in situ information about the geometry of surface complexes on nanoparticles. A new possibility using this technique is illustrated here with the MoO42 -/goethite system. Using deuterated goethite to avoid spectral interferences, adsorption of molybdate ions on a spontaneous oriented film of nanoparticles has been followed using a polarized infrared beam. From the decomposition of spectra in the x, y and z directions, a monodentate surface complex on the {101} faces has been found as the most probable geometry. This result demonstrates that polarized ATR-IR allows to characterize in more details adsorption mode at the atomic scale, in comparison with usual ATR-IR spectroscopy.

  7. Characterization of Paracoccidioides brasiliensis by FT-IR spectroscopy and nanotechnology.

    Science.gov (United States)

    Ferreira, Isabelle; Ferreira-Strixino, Juliana; Castilho, Maiara L; Campos, Claudia B L; Tellez, Claudio; Raniero, Leandro

    2016-01-01

    Paracoccidioides brasiliensis, the etiological agent of paracoccidioidomycosis, is a dimorphic fungus existing as mycelia in the environment (or at 25°C in vitro) and as yeast cells in the human host (or at 37°C in vitro). Because mycological examination of lesions in patients frequently is unable to show the presence of the fungus and serological tests can misdiagnose the disease with other mycosis, the development of new approach's for molecular identification of P. brasiliensis spurges is needed. This study describes the use of a gold nanoprobe of a known gene sequence of P. brasiliensis as a molecular tool to identify P. brasiliensis by regular polymerase chain reaction (PCR) associated with a colorimetric methods. This approach is suitable for testing in remote areas because it does not require any further step than gene amplification, being safer and cheaper than electrophoresis methods. The proposed test showed a color change of the PCR reaction mixture from red to blue in negative samples, whereas the solution remains red in positive samples. We also performed a Fourier Transform Infrared (FT-IR) Spectroscopy analysis to characterize and compare the chemical composition between yeast and mycelia forms, which revealed biochemical differences between these two forms. The analysis of the spectra showed that differences were distributed in chemical bonds of proteins, lipids and carbohydrates. The most prominent difference between both forms was vibration modes related to 1,3-β-glucan usually found in mycelia and 1,3-α-glucan found in yeasts and also chitin forms. In this work, we introduce FT-IR as a new method suitable to reveal overall differences that biochemically distinguish each form of P. brasiliensis that could be additionally used to discriminate biochemical differences among a single form under distinct environmental conditions.

  8. Characterization of Paracoccidioides brasiliensis by FT-IR spectroscopy and nanotechnology

    Science.gov (United States)

    Ferreira, Isabelle; Ferreira-Strixino, Juliana; Castilho, Maiara L.; Campos, Claudia B. L.; Tellez, Claudio; Raniero, Leandro

    2016-01-01

    Paracoccidioides brasiliensis, the etiological agent of paracoccidioidomycosis, is a dimorphic fungus existing as mycelia in the environment (or at 25 °C in vitro) and as yeast cells in the human host (or at 37 °C in vitro). Because mycological examination of lesions in patients frequently is unable to show the presence of the fungus and serological tests can misdiagnose the disease with other mycosis, the development of new approach's for molecular identification of P. brasiliensis spurges is needed. This study describes the use of a gold nanoprobe of a known gene sequence of P. brasiliensis as a molecular tool to identify P. brasiliensis by regular polymerase chain reaction (PCR) associated with a colorimetric methods. This approach is suitable for testing in remote areas because it does not require any further step than gene amplification, being safer and cheaper than electrophoresis methods. The proposed test showed a color change of the PCR reaction mixture from red to blue in negative samples, whereas the solution remains red in positive samples. We also performed a Fourier Transform Infrared (FT-IR) Spectroscopy analysis to characterize and compare the chemical composition between yeast and mycelia forms, which revealed biochemical differences between these two forms. The analysis of the spectra showed that differences were distributed in chemical bonds of proteins, lipids and carbohydrates. The most prominent difference between both forms was vibration modes related to 1,3-β-glucan usually found in mycelia and 1,3-α-glucan found in yeasts and also chitin forms. In this work, we introduce FT-IR as a new method suitable to reveal overall differences that biochemically distinguish each form of P. brasiliensis that could be additionally used to discriminate biochemical differences among a single form under distinct environmental conditions.

  9. Impact and radiation influence on solid hydrocarbon transformation and structuring (by IR-spectroscopy)

    Science.gov (United States)

    Kovaleva, O.

    2009-04-01

    Solid hydrocarbons (bitumens)-typical specimens of natural organic minerals-are one of the most essential objects of petroleum geology and at the same time-one of the least investigated objects of organic mineralogy. Moreover they can be treated as admissible analogs of meteorite carbonaceous materials. According to terrestrial analog of meteoritic organic matter it's possible to estimate the chemical structure of extraterrestrial matter. Further investigation of impact force and radiation influence on the bitumen chemical structure change will make it possible to connect them with extraterrestrial organic matter. This work represents the research of impact influence on the processes of transformation and structuring of asphaltite and changes in the molecular structure of solid bitumens constituting the carbonization series (asphaltite--kerite--anthraxolite), which were subjected to the impact of high radiation doses (10 and 100 Mrad) by infrared spectroscopy (IRS). In percussion experiments peak pressure varied from 10 to 63.4 GPa; temperature - from the first tens degrees to several hundreds degrees Celsius. The radiation experiment was performed in the Arzamas-16 Federal Nuclear Center in line with conditions described in [1]. Asphaltite, which sustained shock load from 17.3 to 23 GPa, didn't undergo considerable changes in its element composition. Though their IR-spectra differ from the spectrum of initial asphaltite by heightened intensity of absorption bands of aromatic groups, as well as by insignificant rise of heterogroups and condensed structures oscillation strength. At the same time the intensity of aliphatic (СН2 and СН3) groups absorption hasn't changed. Probably there've just been the carbon and hydrogen atomic rearrangement. However, shock load up to 26.7 GPa leads to asphaltite transformation into the albertite. There've been observed the intensity decrease of aliphatic groups on its IR-spectrum. Under growth of shock load up to 60 GPa bitumen

  10. The deposition characteristics of copper(I) compounds for CVD by FT-IR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hardcastle, F.D.; Peden, C.H.F.; Omstead, T.R.; Blewer, R.S. [Sandia National Labs., Albuquerque, NM (United States); Farkas, J.; Hampden-Smith, M.J.; Kodas, T.T. [New Mexico Univ., Albuquerque, NM (United States)

    1991-12-31

    Fourier transform-infrared spectroscopy (FT-IR) was used to investigate the adsorption and thermally-induced decomposition of copper (I) {beta}-diketonate precursors of the type (hfac)CuL, where hfac is the hexafluoroacetylacetonate bidentate ligand and L is trimethylphosphine or 1,5-cyclooctadiene. The (hfac)CuPMe{sub 3} precursor desorbs from the surface at very low temperatures whereas the (hfac)Cu(1,5-COD) dissociates on adsorption, liberating 1,5-COD and leaving a surface(hfac)Cu complex which can subsequently disproportionate. Evidence is provided for hydrogen-bonding between the hfac ligand and the surface silanols for (hfac)CuPMe{sub 3}, but not for (hfac)Cu(1,5-COD). These results are consistent with the selective behavior of these precursors for copper deposition and suggest that the selectivity of the (hfac)CuPMe{sub 3} and (hfac)Cu(1, 5-COD) precursors may be due to the ability of the hfac ligand to hydrogen bond to the surface silanol groups.

  11. The deposition characteristics of copper(I) compounds for CVD by FT-IR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hardcastle, F.D.; Peden, C.H.F.; Omstead, T.R.; Blewer, R.S. (Sandia National Labs., Albuquerque, NM (United States)); Farkas, J.; Hampden-Smith, M.J.; Kodas, T.T. (New Mexico Univ., Albuquerque, NM (United States))

    1991-01-01

    Fourier transform-infrared spectroscopy (FT-IR) was used to investigate the adsorption and thermally-induced decomposition of copper (I) {beta}-diketonate precursors of the type (hfac)CuL, where hfac is the hexafluoroacetylacetonate bidentate ligand and L is trimethylphosphine or 1,5-cyclooctadiene. The (hfac)CuPMe{sub 3} precursor desorbs from the surface at very low temperatures whereas the (hfac)Cu(1,5-COD) dissociates on adsorption, liberating 1,5-COD and leaving a surface(hfac)Cu complex which can subsequently disproportionate. Evidence is provided for hydrogen-bonding between the hfac ligand and the surface silanols for (hfac)CuPMe{sub 3}, but not for (hfac)Cu(1,5-COD). These results are consistent with the selective behavior of these precursors for copper deposition and suggest that the selectivity of the (hfac)CuPMe{sub 3} and (hfac)Cu(1, 5-COD) precursors may be due to the ability of the hfac ligand to hydrogen bond to the surface silanol groups.

  12. Investigation of calcium aluminates by IR spectroscopy in diffusely scattered light

    Energy Technology Data Exchange (ETDEWEB)

    Medin, A.S.; Borovkov, V.Yu.; Nissenbaum, V.D.; Yakerson, V.I.; Kazanskii, V.B.

    1989-01-01

    The hydroxyl covering and the adsorption sites for CO and H/sub 2/O on aluminum-calcium catalysts and supports with developed surfaces have been studied by IR spectroscopy in diffusely scattered light. The presence of several types of surface OH groups, viz., terminal groups bonded to calcium ions with different types of coordination, bridging OH groups, and groups appearing in (CaOH)/sup +/ groupings, which perform the role of compensating cations in the zeolite-like structure of calcium aluminates, has been established. The shifts of the bands of the OH groups upon the adsorption of C/sub 6/H/sub 6/ and cyclo-C/sub 6/H/sub 12/ point out their weakly acidic or basic character. When calcium aluminates are dehydroxylated, aprotic sites appear on their surfaces, and the rehydration of such surfaces is accompanied by the formation of OH groups and the weakening of the Al-O-M bonds (M = Al, Ca) with the appearance of additional sites for the strong adsorption of water.

  13. IR spectroscopy of monohydrated tryptamine cation: Rearrangement of the intermolecular hydrogen bond induced by photoionization

    Science.gov (United States)

    Sakota, Kenji; Kouno, Yuuki; Harada, Satoshi; Miyazaki, Mitsuhiko; Fujii, Masaaki; Sekiya, Hiroshi

    2012-12-01

    Rearrangement of intermolecular hydrogen bond in a monohydrated tryptamine cation, [TRA(H2O)1]+, has been investigated in the gas phase by IR spectroscopy and quantum chemical calculations. In the S0 state of TRA(H2O)1, a water molecule is hydrogen-bonded to the N atom of the amino group of a flexible ethylamine side chain [T. S. Zwier, J. Phys. Chem. A 105, 8827 (2001), 10.1021/jp011659+]. A remarkable change in the hydrogen-bonding motif of [TRA(H2O)]+ occurs upon photoionization. In the D0 state of [TRA(H2O)1]+, the water molecule is hydrogen-bonded to the NH group of the indole ring of TRA+, indicating that the water molecule transfers from the amino group to NH group. Quantum chemical calculations are performed to investigate the pathway of the water transfer. Two potential energy barriers emerge in [TRA(H2O)1]+ along the intrinsic reaction coordinate of the water transfer. The water transfer event observed in [TRA(H2O)1]+ is not an elementary but a complex process.

  14. Conformations of 1-heptene secondary ozonide as studied by low temperature FT-IR spectroscopy

    Science.gov (United States)

    Bariseviciute, R.; Ceponkus, J.; Sablinskas, V.; Kimtys, L.

    2007-11-01

    Conformational diversity of the 1-heptene secondary ozonides (SOZ) in solid neat films as well as isolated in Ar or CO 2 matrices was studied by the means of FT-IR absorption spectroscopy. The ozonization reaction was performed at 77 K in the neat films of the reactants. The spectra of the ozonide were analyzed by combining the experimental data with the results of theoretical calculations performed at B3LYP 6-311++G (3df, 3pd) level. It was found that the samples of 1-heptene secondary ozonide exist as a mixture of three dominating conformers. The most stable conformer is the one with O-O half-chair configuration of the five membered ring, the aliphatic radical attached to the ring in equatorial position and the aliphatic chain being in gauche (∠OCCC ≈ -60°) position. The other two stable conformers are equatorial with aliphatic chain in anti (∠OCCC ≈ 180°) and gauche (∠OCCC ≈ 60°) positions. It was found from Van't Hoff plots that Δ H of the equatorial anti conformer is equal to 0.24 ± 0.03 kJ/mol. The experimental value of Δ H is in reasonable accordance to the calculated one - 0.5 kJ/mol.

  15. Investigation of the hydrated 7-hydroxy-4-methylcoumarin dimer by combined IR/UV spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Stamm, A.; Schwing, K.; Gerhards, M., E-mail: gerhards@chemie.uni-kl.de [TU Kaiserslautern, Fachbereich Chemie and Research Center Optimas, Erwin-Schroedinger-Straße 52, D-67663 Kaiserslautern (Germany)

    2014-11-21

    The first molecular beam investigations on a coumarin dimer and clusters of a coumarin dimer with water both in the neutral (S{sub 0}) and cationic (D{sub 0}) electronic ground state are performed. The structure and structural changes due to ionization of the isolated 7-hydroxy-4-methylcoumarin dimer (7H4MC){sub 2} as well as its mono- and dihydrate (7H4MC){sub 2}(H{sub 2}O){sub 1-2} are analyzed by applying combined IR/UV spectroscopy compared with density functional theory calculations. In case of the neutral dimer of 7H4MC a doubly hydrogen-bonded structure is formed. This doubly hydrogen-bonded arrangement opens to a singly hydrogen-bonded structure in the ion presenting a rearrangement reaction within an isolated dimer. By attaching one or two water molecules to the neutral 7H4MC dimer water is inserted into the hydrogen bonds. In contrast to the non-hydrated species this general binding motif with water in a bridging function does not change via ionization but especially for the dihydrate the spatial arrangement of the two 7H4MC units changes strengthening the interaction between the aromatic chromophores. The presented analyses illustrate the strong dependence of binding motifs as a function of successive hydration and charge including a rearrangement reaction.

  16. Characteristics of the complexing of chitosan with sodium dodecyl sulfate, according to IR spectroscopy data and quantum-chemical calculations

    Science.gov (United States)

    Shilova, S. V.; Romanova, K. A.; Galyametdinov, Yu. G.; Tret'yakova, A. Ya.; Barabanov, V. P.

    2016-06-01

    The complexing of protonated chitosan with dodecyl sulfate ions in water solutions is studied using IR spectroscopy data and quantum-chemical calculations. It is established that the electrostatic interaction between the protonated amino groups of chitosan and dodecyl sulfate ions is apparent in the IR spectrum as a band at 833 cm-1. The need to consider the effect the solvent has on the formation of hydrogen-bound ion pairs [CTS+ ṡ C12H25O 3 - ] is shown via a quantum-chemical simulation of the equilibrium geometry and the energy characteristics of complexing and hydration.

  17. Near-infrared (NIR) imaging analysis of polylactic acid (PLA) nanocomposite by multiple-perturbation two-dimensional (2D) correlation spectroscopy

    Science.gov (United States)

    Shinzawa, Hideyuki; Murakami, Takurou N.; Nishida, Masakazu; Kanematsu, Wataru; Noda, Isao

    2014-07-01

    Multiple-perturbation two-dimensional (2D) correlation spectroscopy was applied to sets of near-infrared (NIR) imaging data of polylactic acid (PLA) nanocomposite samples undergoing UV degradation. Incorporation of clay nanoparticles substantially lowers the surface free energy barrier for the nucleation of PLA and eventually increases the frequency of the spontaneous nucleation of PLA crystals. Thus, when exposed to external stimuli such as UV light, PLA nanocomposite may show different structure alternation depending on the clay dispersion. Multiple-perturbation 2D correlation analysis of the PLA nanocomposite samples revealed different spatial variation between crystalline and amorphous structure of PLA, and the phenomenon especially becomes acute in the region where the clay particles are coagulated. The incorporation of the clay leads to the cleavage-induced crystallization of PLA when the sample is subjected to the UV light. The additional development of the ordered crystalline structure then works favorably to restrict the initial degradation of the polymer, providing the delay in the weight loss of the PLA.

  18. Mid-IR properties of Seyferts: Spitzer/IRS spectroscopy of the IRAS 12micron Seyfert sample

    CERN Document Server

    Charmandaris, V; Huang, J; Spinoglio, L; Tommasin, S

    2009-01-01

    We performed an analysis of the mid-infared properties of the 12micron Seyfert sample, a complete unbiased 12micron flux limited sample of local Seyfert galaxies selected from the IRAS Faint Source Catalog, based on low resolution spectra obtained with the Infrared Spectrograph (IRS) on-board Spitzer Space Telescope. A detailed presentation of this analysis is dicussed in Wu et al. (2009). We find that on average, the 15-30micron slope of the continuum is -0.85+/-0.61 for Seyfert 1s and -1.53+/-0.84 for Seyfert 2s, and there is substantial scatter in each type. Moreover, nearly 32% of Seyfert 1s, and 9% of Seyfert 2s, display a peak in the mid-infrared spectrum at 20micron, which is attributed to an additional hot dust component. The Polycyclic Aromatic Hydrocarbon (PAH) equivalent width decreases with increasing dust temperature, as indicated by the global infrared color of the host galaxies. However, no statistical difference in PAH equivalent width is detected between the two Seyfert types, 1 and 2, of the...

  19. Tunable Microcavity-Stabilized Quantum Cascade Laser for Mid-IR High-Resolution Spectroscopy and Sensing

    Directory of Open Access Journals (Sweden)

    Simone Borri

    2016-02-01

    Full Text Available The need for highly performing and stable methods for mid-IR molecular sensing and metrology pushes towards the development of more and more compact and robust systems. Among the innovative solutions aimed at answering the need for stable mid-IR references are crystalline microresonators, which have recently shown excellent capabilities for frequency stabilization and linewidth narrowing of quantum cascade lasers with compact setups. In this work, we report on the first system for mid-IR high-resolution spectroscopy based on a quantum cascade laser locked to a CaF2 microresonator. Electronic locking narrows the laser linewidth by one order of magnitude and guarantees good stability over long timescales, allowing, at the same time, an easy way for finely tuning the laser frequency over the molecular absorption line. Improvements in terms of resolution and frequency stability of the source are demonstrated by direct sub-Doppler recording of a molecular line.

  20. Tunable Microcavity-Stabilized Quantum Cascade Laser for Mid-IR High-Resolution Spectroscopy and Sensing

    Science.gov (United States)

    Borri, Simone; Siciliani de Cumis, Mario; Insero, Giacomo; Bartalini, Saverio; Cancio Pastor, Pablo; Mazzotti, Davide; Galli, Iacopo; Giusfredi, Giovanni; Santambrogio, Gabriele; Savchenkov, Anatoliy; Eliyahu, Danny; Ilchenko, Vladimir; Akikusa, Naota; Matsko, Andrey; Maleki, Lute; De Natale, Paolo

    2016-01-01

    The need for highly performing and stable methods for mid-IR molecular sensing and metrology pushes towards the development of more and more compact and robust systems. Among the innovative solutions aimed at answering the need for stable mid-IR references are crystalline microresonators, which have recently shown excellent capabilities for frequency stabilization and linewidth narrowing of quantum cascade lasers with compact setups. In this work, we report on the first system for mid-IR high-resolution spectroscopy based on a quantum cascade laser locked to a CaF2 microresonator. Electronic locking narrows the laser linewidth by one order of magnitude and guarantees good stability over long timescales, allowing, at the same time, an easy way for finely tuning the laser frequency over the molecular absorption line. Improvements in terms of resolution and frequency stability of the source are demonstrated by direct sub-Doppler recording of a molecular line. PMID:26901199

  1. Rapid evaluation and quantitative analysis of thyme, origano and chamomile essential oils by ATR-IR and NIR spectroscopy

    Science.gov (United States)

    Schulz, Hartwig; Quilitzsch, Rolf; Krüger, Hans

    2003-12-01

    The essential oils obtained from various chemotypes of thyme, origano and chamomile species were studied by ATR/FT-IR as well as NIR spectroscopy. Application of multivariate statistics (PCA, PLS) in conjunction with analytical reference data leads to very good IR and NIR calibration results. For the main essential oil components (e.g. carvacrol, thymol, γ-terpinene, α-bisabolol and β-farnesene) standard errors are in the range of the applied GC reference method. In most cases the multiple coefficients of determination ( R2) are >0.97. Using the IR fingerprint region (900-1400 cm -1) a qualitative discrimination of the individual chemotypes is possible already by visual judgement without to apply any chemometric algorithms.The described rapid and non-destructive methods can be applied in industry to control very easily purifying, blending and redistillation processes of the mentioned essential oils.

  2. Tunable Microcavity-Stabilized Quantum Cascade Laser for Mid-IR High-Resolution Spectroscopy and Sensing.

    Science.gov (United States)

    Borri, Simone; Siciliani de Cumis, Mario; Insero, Giacomo; Bartalini, Saverio; Cancio Pastor, Pablo; Mazzotti, Davide; Galli, Iacopo; Giusfredi, Giovanni; Santambrogio, Gabriele; Savchenkov, Anatoliy; Eliyahu, Danny; Ilchenko, Vladimir; Akikusa, Naota; Matsko, Andrey; Maleki, Lute; De Natale, Paolo

    2016-01-01

    The need for highly performing and stable methods for mid-IR molecular sensing and metrology pushes towards the development of more and more compact and robust systems. Among the innovative solutions aimed at answering the need for stable mid-IR references are crystalline microresonators, which have recently shown excellent capabilities for frequency stabilization and linewidth narrowing of quantum cascade lasers with compact setups. In this work, we report on the first system for mid-IR high-resolution spectroscopy based on a quantum cascade laser locked to a CaF₂ microresonator. Electronic locking narrows the laser linewidth by one order of magnitude and guarantees good stability over long timescales, allowing, at the same time, an easy way for finely tuning the laser frequency over the molecular absorption line. Improvements in terms of resolution and frequency stability of the source are demonstrated by direct sub-Doppler recording of a molecular line. PMID:26901199

  3. ATR-FT-IR spectroscopy in the region of 500-230 cm -1 for identification of inorganic red pigments

    Science.gov (United States)

    Vahur, Signe; Knuutinen, Ulla; Leito, Ivo

    2009-08-01

    It is demonstrated that micro-ATR-FT-IR in the low wave number range (500-230 cm -1) can be well used for identification of pigments in paint samples thereby markedly extending the possibilities of pigment identification by ATR-IR spectroscopy into the realm of pigments having no absorptions in the mid-IR region. Reference spectra of pigments can be conveniently obtained by mixing them with linseed oil in approximately 1:1 mass ratio. Vermilion (or cinnabar), read lead, different red iron oxide pigments and cadmium red can be identified. In some cases the method can be used alone for pigment identification and in many cases it provides useful additional evidence for pigment identification using other instrumental techniques (electron microprobe analysis, XRF, optical microscopy).

  4. Aminophenol isomers unraveled by conformer-specific far-IR action spectroscopy.

    Science.gov (United States)

    Yatsyna, Vasyl; Bakker, Daniël J; Feifel, Raimund; Rijs, Anouk M; Zhaunerchyk, Vitali

    2016-02-17

    Spectroscopic studies of molecular structure can strongly benefit from extending the conventional mid-IR range to the far-IR and THz regions, as low-frequency molecular vibrations provide unique fingerprints and high sensitivity to intra- and intermolecular interactions. In this work, the gas-phase conformer specific far-IR spectra of aminophenol isomers, recorded in the spectral range of 220-800 cm(-1) at the free-electron laser laboratory FELIX in Nijmegen (the Netherlands), are reported. Many distinct far-IR vibrational signatures which are specific for the molecular structure of the different aminophenol isomers are revealed and assigned. The observed far-IR transitions of the NH2 wagging (inversion) motion have been treated with a double-minimum harmonic well potential model that has enabled us to obtain the inversion barrier values. Moreover, we discuss the limitations and capability of conventional DFT frequency calculations to describe the far-IR vibrational modes. PMID:26854118

  5. Formation of host–guest complexes on gold surface investigated by surface-enhanced IR absorption spectroscopy

    OpenAIRE

    Inokuchi, Yoshiya; Mizuuchi, Takahiro; Ebata, Takayuki; Ikeda, Toshiaki; Haino, Takeharu; Kimura, Tetsunari; Guo, Hao; Furutani, Yuji

    2014-01-01

    We apply surface-enhanced infrared absorption (SEIRA) spectroscopy to host-guest complexes in liquid phase to examine the structural change in the complex formation. Two thiol derivatives of 18-crown-6 (18C6) are chemisorbed on a gold surface, and aqueous solutions of MCl salts (M = Li, Na, K, Rb, and Cs) are put to form M+・18C6 complexes. Infrared spectra of these complexes in the 900-2000 cm-1 region are obtained by SEIRA spectroscopy. The observed IR spectra show noticeable peaks due to th...

  6. The application of the derivative IR-spectroscopy and HPLC-ESI-MS/MS in the analysis of archaeology resin

    Science.gov (United States)

    Zareva, S.; Kuleff, I.

    2010-07-01

    The applicability of the reducing-difference procedure for the interpretation of the conventional IR-spectroscopy as successful scientific technique for the analysis of ancient and modern resins has been demonstrated. The new temperature tool for modeling of the ancient resin samples has also been shown. The experimental infrared data are supported by the hydride approach of HPLC-MS-MS with ES-ionisation.

  7. Cellulose Structural Polymorphism in Plant Primary Cell Walls Investigated by High-Field 2D Solid-State NMR Spectroscopy and Density Functional Theory Calculations.

    Science.gov (United States)

    Wang, Tuo; Yang, Hui; Kubicki, James D; Hong, Mei

    2016-06-13

    The native cellulose of bacterial, algal, and animal origins has been well studied structurally using X-ray and neutron diffraction and solid-state NMR spectroscopy, and is known to consist of varying proportions of two allomorphs, Iα and Iβ, which differ in hydrogen bonding, chain packing, and local conformation. In comparison, cellulose structure in plant primary cell walls is much less understood because plant cellulose has lower crystallinity and extensive interactions with matrix polysaccharides. Here we have combined two-dimensional magic-angle-spinning (MAS) solid-state nuclear magnetic resonance (solid-state NMR) spectroscopy at high magnetic fields with density functional theory (DFT) calculations to obtain detailed information about the structural polymorphism and spatial distributions of plant primary-wall cellulose. 2D (13)C-(13)C correlation spectra of uniformly (13)C-labeled cell walls of several model plants resolved seven sets of cellulose chemical shifts. Among these, five sets (denoted a-e) belong to cellulose in the interior of the microfibril while two sets (f and g) can be assigned to surface cellulose. Importantly, most of the interior cellulose (13)C chemical shifts differ significantly from the (13)C chemical shifts of the Iα and Iβ allomorphs, indicating that plant primary-wall cellulose has different conformations, packing, and hydrogen bonding from celluloses of other organisms. 2D (13)C-(13)C correlation experiments with long mixing times and with water polarization transfer revealed the spatial distributions and matrix-polysaccharide interactions of these cellulose structures. Celluloses f and g are well mixed chains on the microfibril surface, celluloses a and b are interior chains that are in molecular contact with the surface chains, while cellulose c resides in the core of the microfibril, outside spin diffusion contact with the surface. Interestingly, cellulose d, whose chemical shifts differ most significantly from those of

  8. UV and IR Spectroscopy of Cold H2O(+)-Benzo-Crown Ether Complexes.

    Science.gov (United States)

    Inokuchi, Yoshiya; Ebata, Takayuki; Rizzo, Thomas R

    2015-11-12

    The H2O(+) radical ion, produced in an electrospray ion source via charge transfer from Eu(3+), is encapsulated in benzo-15-crown-5 (B15C5) or benzo-18-crown-6 (B18C6). We measure UV photodissociation (UVPD) spectra of the (H2O·B15C5)(+) and (H2O·B18C6)(+) complexes in a cold, 22-pole ion trap. These complexes show sharp vibronic bands in the 35 700-37 600 cm(-1) region, similar to the case of neutral B15C5 or B18C6. These results indicate that the positive charge in the complexes is localized on H2O, giving the forms H2O(+)·B15C5 and H2O(+)·B18C6, in spite of the fact that the ionization energy of B15C5 and B18C6 is lower than that of H2O. The formation of the H2O(+) complexes and the suppression of the H3O(+) production through the reaction of H2O(+) and H2O can be attributed to the encapsulation of hydrated Eu(3+) clusters by B15C5 and B18C6. On the contrary, the main fragment ions subsequent to the UV excitation of these complexes are B15C5(+) and B18C6(+) radical ions; the charge transfer occurs from H2O(+) to B15C5 and B18C6 after the UV excitation. The position of the band origin for the H2O(+)·B18C6 complex (36323 cm(-1)) is almost the same as that for Rb(+)·B18C6 (36315 cm(-1)); the strength of the intermolecular interaction of H2O(+) with B18C6 is similar to that of Rb(+). The spectral features of the H2O(+)·B15C5 complex also resemble those of the Rb(+)·B15C5 ion. We measure IR-UV spectra of these complexes in the CH and OH stretching region. Four conformers are found for the H2O(+)·B15C5 complex, but there is one dominant form for the H2O(+)·B18C6 ion. This study demonstrates the production of radical ions by charge transfer from multivalent metal ions, their encapsulation by host molecules, and separate detection of their conformers by cold UV spectroscopy in the gas phase.

  9. Formation of host-guest complexes on gold surface investigated by surface-enhanced IR absorption spectroscopy

    Science.gov (United States)

    Inokuchi, Yoshiya; Mizuuchi, Takahiro; Ebata, Takayuki; Ikeda, Toshiaki; Haino, Takeharu; Kimura, Tetsunari; Guo, Hao; Furutani, Yuji

    2014-01-01

    We apply surface-enhanced infrared absorption (SEIRA) spectroscopy to host-guest complexes in liquid phase to examine the structural change in the complex formation. Two thiol derivatives of 18-crown-6 (18C6) are chemisorbed on a gold surface, and aqueous solutions of MCl salts (M = Li, Na, K, Rb, and Cs) are put to form M+·18C6 complexes. Infrared spectra of these complexes in the 900-2000 cm-1 region are obtained by SEIRA spectroscopy. The observed IR spectra show noticeable peaks due to the complex formation, demonstrating that SEIRA spectroscopy will be a powerful method to investigate the structure of host-guest complexes in supramolecular chemistry.

  10. Spitzer/IRS spectroscopy of high mass precursors to planetary nebulae

    OpenAIRE

    Garcia-Hernandez, D. A.; Perea-Calderon, J. V.; Bobrowsky, M.; Garcia-Lario, P.

    2007-01-01

    We present Spitzer/IRS observations of a small sample of heavily obscured IRAS sources displaying both the infrared and OH maser emission characteristic of OH/IR stars on the asymptotic giant branch (AGB), but also radio continuum emission typical of ionized planetary nebulae (PNe), the so-called OHPNe. Our observations show that their mid-infrared spectra are dominated by the simultaneous presence of strong and broad amorphous silicate absorption features together with crystalline silicate f...

  11. Evaluation of Turmeric Powder Adulterated with Metanil Yellow Using FT-Raman and FT-IR Spectroscopy

    Directory of Open Access Journals (Sweden)

    Sagar Dhakal

    2016-05-01

    Full Text Available Turmeric powder (Curcuma longa L. is valued both for its medicinal properties and for its popular culinary use, such as being a component in curry powder. Due to its high demand in international trade, turmeric powder has been subject to economically driven, hazardous chemical adulteration. This study utilized Fourier Transform-Raman (FT-Raman and Fourier Transform-Infra Red (FT-IR spectroscopy as separate but complementary methods for detecting metanil yellow adulteration of turmeric powder. Sample mixtures of turmeric powder and metanil yellow were prepared at concentrations of 30%, 25%, 20%, 15%, 10%, 5%, 1%, and 0.01% (w/w. FT-Raman and FT-IR spectra were acquired for these mixture samples as well as for pure samples of turmeric powder and metanil yellow. Spectral analysis showed that the FT-IR method in this study could detect the metanil yellow at the 5% concentration, while the FT-Raman method appeared to be more sensitive and could detect the metanil yellow at the 1% concentration. Relationships between metanil yellow spectral peak intensities and metanil yellow concentration were established using representative peaks at FT-Raman 1406 cm−1 and FT-IR 1140 cm−1 with correlation coefficients of 0.93 and 0.95, respectively.

  12. Fine Structure of Hydrogen Bond in Cholic Acid Revealed by 2DIR Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Based on cryogenic FT-IR spectroscopic studies of hydrogen bonds in cholic acid, two-dimensional FT-IR spectroscopy was applied to enhance our understanding of the hydrogen bonds of cholic acid. Fine spectral structures were revealed by asynchronous 2D FT-IR spectra. The co-relationship among various bands was discussed according to the synchronous 2D FT-IR spectrum.

  13. Non-destructive and in situ identification of rice paper, seals and pigments by FT-IR and XRD spectroscopy.

    Science.gov (United States)

    Na, Na; Ouyang, Qi-Ming; Ma, Hui; Ouyang, Jin; Li, Yanping

    2004-11-15

    This paper studied the chemical characteristics of rice paper, pigments and seals on Chinese calligraphies and traditional Chinese paintings. The techniques used here were Fourier transform infrared (FT-IR) spectroscopy and X-ray diffraction (XRD). FT-IR allows good identification of the substances present in pigments and inkpads and differentiates each era of rice paper. This can be the base of estimating the age of rice paper. Different crystalline phases can be identified by XRD, which is further evidence to separate different kinds of pigments or inkpads. Both of these methods were non-destructive in situ analysis and can be used in the identification in calligraphies and traditional Chinese paintings. These results confirmed that the applied techniques are relatively quicker and more reliable than traditional approaches authenticated by years of experience. PMID:18969703

  14. Constant-time 2D and 3D through-bond correlation NMR spectroscopy of solids under 60 kHz MAS

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Rongchun; Ramamoorthy, Ayyalusamy, E-mail: ramamoor@umich.edu [Biophysics and Department of Chemistry, The University of Michigan, Ann Arbor, Michigan 48109-1055 (United States)

    2016-01-21

    Establishing connectivity and proximity of nuclei is an important step in elucidating the structure and dynamics of molecules in solids using magic angle spinning (MAS) NMR spectroscopy. Although recent studies have successfully demonstrated the feasibility of proton-detected multidimensional solid-state NMR experiments under ultrafast-MAS frequencies and obtaining high-resolution spectral lines of protons, assignment of proton resonances is a major challenge. In this study, we first re-visit and demonstrate the feasibility of 2D constant-time uniform-sign cross-peak correlation (CTUC-COSY) NMR experiment on rigid solids under ultrafast-MAS conditions, where the sensitivity of the experiment is enhanced by the reduced spin-spin relaxation rate and the use of low radio-frequency power for heteronuclear decoupling during the evolution intervals of the pulse sequence. In addition, we experimentally demonstrate the performance of a proton-detected pulse sequence to obtain a 3D {sup 1}H/{sup 13}C/{sup 1}H chemical shift correlation spectrum by incorporating an additional cross-polarization period in the CTUC-COSY pulse sequence to enable proton chemical shift evolution and proton detection in the incrementable t{sub 1} and t{sub 3} periods, respectively. In addition to through-space and through-bond {sup 13}C/{sup 1}H and {sup 13}C/{sup 13}C chemical shift correlations, the 3D {sup 1}H/{sup 13}C/{sup 1}H experiment also provides a COSY-type {sup 1}H/{sup 1}H chemical shift correlation spectrum, where only the chemical shifts of those protons, which are bonded to two neighboring carbons, are correlated. By extracting 2D F1/F3 slices ({sup 1}H/{sup 1}H chemical shift correlation spectrum) at different {sup 13}C chemical shift frequencies from the 3D {sup 1}H/{sup 13}C/{sup 1}H spectrum, resonances of proton atoms located close to a specific carbon atom can be identified. Overall, the through-bond and through-space homonuclear/heteronuclear proximities determined from the

  15. DIFERENCIACIÓN DE ESPECIE MICOBACTERIANA POR FT-IR (ESPECTROSCOPIA INFRARROJA CON TRANSFORMADA DE FOURIER Differentiation of Mycobacterial Species by FT-IR (Fourier Transform Infrared Spectroscopy

    Directory of Open Access Journals (Sweden)

    JORGE ANDRÉS CUÉLLAR GIL

    2011-08-01

    Full Text Available Se trabajó con espectroscopía infrarroja transformada de Fourier (FT-IR para diferenciar diez especies de micobacterias. Mycobacterium intracelullare y M. fortuitum (ATCC, M. flavensces, M. smegmatis, M. chelone, M. gordonae, M. triviale, M. vaccae, M. terrae y M. nonchromogenicum (IP. Como control de diferenciación de género se incluyó Staphylococcus aureus, Streptococcus viridans y Streptococcus pyogenes, Klebsiella pneumoniae y Escherichia coli, cada especie se corrió por triplicado en KBr y ATR. Los espectros se analizaron según el método de diferenciación de componentes principales, y se realizaron derivadas de primer orden (D1 en modalidad de transmisión usando la pastilla de KBr y la base ATR, además se diseñó una biblioteca espectral con la primera derivada de ATR. La sensibilidad de detección fue de 100% al trabajar con KBr y el nivel de diferenciación fue de 100% en tres de cuatro muestras problema.Spectroscopy Fourier Transform infrared (FT-IR was used to differentiate 10 species of mycobacteria. Mycobacterium intracelullare and M. fortuitum (ATCC. M. flavensces, M. smegmatis, M. chelone, M. gordonae, M. triviale, M. vaccae, M. terrae and M. nonchromogenicum (IP. For gender differentiation Staphylococcus aureus, Streptococcus viridans and Streptococcus pyogenes, Klebsiella pneumoniae y Escherichia coli were incluided as controls, each species was run for triplicate in KBr and ATR. The spectra were analyzed with the method of principal components to make the first derivatives of first order (D1 in the transmission mode using KBr pellet and ATR base, and a spectral library of the first derivative of ATR was kept. The detection sensitivity was 100% with KBr and the level of differentiation was 100% in three of the four samples problems.

  16. Impact of Humidity on Quartz-Enhanced Photoacoustic Spectroscopy Based CO Detection Using a Near-IR Telecommunication Diode Laser

    OpenAIRE

    Xukun Yin; Lei Dong; Huadan Zheng; Xiaoli Liu; Hongpeng Wu; Yanfang Yang; Weiguang Ma; Lei Zhang; Wangbao Yin; Liantuan Xiao; Suotang Jia

    2016-01-01

    A near-IR CO trace gas sensor based on quartz-enhanced photoacoustic spectroscopy (QEPAS) is evaluated using humidified nitrogen samples. Relaxation processes in the CO-N2-H2O system are investigated. A simple kinetic model is used to predict the sensor performance at different gas pressures. The results show that CO has a ~3 and ~5 times slower relaxation time constant than CH4 and HCN, respectively, under dry conditions. However, with the presence of water, its relaxation time constant can ...

  17. NEAR-IR Spectroscopy of Young Stars in the Braid Nebula Star Formation Region in Cygnus Ob7

    OpenAIRE

    Aspin, Colin; Beck, Tracy L.; Pyo, Tae-Soo; Davis, Chris J.; Schieven, G. M.; Khanzadyan, Tigran; Magakian, Tigran; Movsessian, Tigran; NIkogossian, Elena G.; Mitchison, Sharon; Smith, Michael D.

    2008-01-01

    We present 1.4 to 2.5 um integral field spectroscopy of 16 stars in the Braid Nebula star formation region in Cygnus OB7. These data forms one aspect of a large-scale multi-wavelength survey aimed at determining an unbiased estimate of the number, mass distribution, and evolutionary state of the young stars within this one square degree area of the previously poorly studied Lynds 1003 molecular cloud. Our new spectroscopic data, when combined with 2MASS near-IR photometry, provide evidence of...

  18. MRI and 2D-CSI MR spectroscopy of the brain in the evaluation of patients with acute onset of neuropsychiatric systemic lupus erythematosus

    International Nuclear Information System (INIS)

    MRI and 2D-CSI spectroscopy were performed in eight patients with systemic lupus erythematosus who presented with acute onset of neuropsychiatric lupus (NP-SLE), and in seven normal controls to evaluate for differences in metabolic peaks and metabolic ratios between the two groups. Also, the interval change of the metabolic peaks and their ratios during treatment in the NP-SLE patient group was evaluated. Metabolic peaks for N-acetyl-aspartate (NAA), choline (Cho), creatine (Cr), and lactate/lipids (LL) and their ratios (NAA/Cr, NAA/Cho, Cho/Cr, LL/Cr) were determined at initial presentation and 3 and 6 months later. In the eight lupus patients compared to the seven normal controls, NAA/Cho ratios were lower at presentation (1.05 vs 1.25; p = 0.004) and decreased even further at the three month follow-up (0.92 vs 1.05; p = 0.008). In contrast, both Cho/Cr (1.42 vs 1.26; p = 0.026) and LL/Cr ratios (0.26 vs 0.19; p = 0.002) were higher in the lupus patients at presentation compared to the controls and did not significantly change at three and six months follow-up. The NAA/Cr ratios were lower in the lupus patients compared to the controls at presentation but the difference was not statistically significant. However, the mean NAA/Cr significantly decreased from the initial examination to the three month follow-up (1.42 vs 1.32; p = 0.049) but did not significantly change from the three to the six month follow-up examinations. The NAA/Cr, Cho/Cr, and NAA/Cho ratios varied significantly (p < 0.05, p < 0.05, p < 0.05, respectively) between the 17 different locations measured in the brain in all eight patients and seven controls. Both the NAA/Cr ratios and the Cho/Cr ratios were also significantly lower in the gray matter than in the white matter (p < 0.0001) in both patients and controls, whereas the LL/Cr and NAA/Cho ratios were not significantly different. In conclusion, 2D-CSI MR spectroscopy may be useful in the early detection of metabolic CNS changes in NP

  19. MRI and 2D-CSI MR spectroscopy of the brain in the evaluation of patients with acute onset of neuropsychiatric systemic lupus erythematosus

    Energy Technology Data Exchange (ETDEWEB)

    Sundgren, P.C.; Jennings, J.; Gebarski, S.; Pang, Y.; Maly, P. [University of Michigan Health Systems, Department of Radiology, Ann Arbor, MI (United States); Attwood, J.T.; McCune, W.J. [University of Michigan Health Systems, Department of and Rheumatology, Ann Arbor, MI (United States); Nan, B. [University of Michigan Health Systems, School of Public Health, Ann Arbor, MI (United States)

    2005-08-01

    MRI and 2D-CSI spectroscopy were performed in eight patients with systemic lupus erythematosus who presented with acute onset of neuropsychiatric lupus (NP-SLE), and in seven normal controls to evaluate for differences in metabolic peaks and metabolic ratios between the two groups. Also, the interval change of the metabolic peaks and their ratios during treatment in the NP-SLE patient group was evaluated. Metabolic peaks for N-acetyl-aspartate (NAA), choline (Cho), creatine (Cr), and lactate/lipids (LL) and their ratios (NAA/Cr, NAA/Cho, Cho/Cr, LL/Cr) were determined at initial presentation and 3 and 6 months later. In the eight lupus patients compared to the seven normal controls, NAA/Cho ratios were lower at presentation (1.05 vs 1.25; p = 0.004) and decreased even further at the three month follow-up (0.92 vs 1.05; p = 0.008). In contrast, both Cho/Cr (1.42 vs 1.26; p = 0.026) and LL/Cr ratios (0.26 vs 0.19; p = 0.002) were higher in the lupus patients at presentation compared to the controls and did not significantly change at three and six months follow-up. The NAA/Cr ratios were lower in the lupus patients compared to the controls at presentation but the difference was not statistically significant. However, the mean NAA/Cr significantly decreased from the initial examination to the three month follow-up (1.42 vs 1.32; p = 0.049) but did not significantly change from the three to the six month follow-up examinations. The NAA/Cr, Cho/Cr, and NAA/Cho ratios varied significantly (p < 0.05, p < 0.05, p < 0.05, respectively) between the 17 different locations measured in the brain in all eight patients and seven controls. Both the NAA/Cr ratios and the Cho/Cr ratios were also significantly lower in the gray matter than in the white matter (p < 0.0001) in both patients and controls, whereas the LL/Cr and NAA/Cho ratios were not significantly different. In conclusion, 2D-CSI MR spectroscopy may be useful in the early detection of metabolic CNS changes in NP

  20. Dynamics-based selective 2D {sup 1}H/{sup 1}H chemical shift correlation spectroscopy under ultrafast MAS conditions

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Rongchun; Ramamoorthy, Ayyalusamy, E-mail: ramamoor@umich.edu [Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055 (United States)

    2015-05-28

    Dynamics plays important roles in determining the physical, chemical, and functional properties of a variety of chemical and biological materials. However, a material (such as a polymer) generally has mobile and rigid regions in order to have high strength and toughness at the same time. Therefore, it is difficult to measure the role of mobile phase without being affected by the rigid components. Herein, we propose a highly sensitive solid-state NMR approach that utilizes a dipolar-coupling based filter (composed of 12 equally spaced 90° RF pulses) to selectively measure the correlation of {sup 1}H chemical shifts from the mobile regions of a material. It is interesting to find that the rotor-synchronized dipolar filter strength decreases with increasing inter-pulse delay between the 90° pulses, whereas the dipolar filter strength increases with increasing inter-pulse delay under static conditions. In this study, we also demonstrate the unique advantages of proton-detection under ultrafast magic-angle-spinning conditions to enhance the spectral resolution and sensitivity for studies on small molecules as well as multi-phase polymers. Our results further demonstrate the use of finite-pulse radio-frequency driven recoupling pulse sequence to efficiently recouple weak proton-proton dipolar couplings in the dynamic regions of a molecule and to facilitate the fast acquisition of {sup 1}H/{sup 1}H correlation spectrum compared to the traditional 2D NOESY (Nuclear Overhauser effect spectroscopy) experiment. We believe that the proposed approach is beneficial to study mobile components in multi-phase systems, such as block copolymers, polymer blends, nanocomposites, heterogeneous amyloid mixture of oligomers and fibers, and other materials.

  1. Organic Spectroscopy Laboratory: Utilizing IR and NMR in the Identification of an Unknown Substance

    Science.gov (United States)

    Glagovich, Neil M.; Shine, Timothy D.

    2005-01-01

    A laboratory experiment that emphasizes the interpretation of both infrared (IR) and nuclear magnetic resonance (NMR) spectra in the elucidation of the structure of an unknown compound was developed. The method helps students determine [to the first power]H- and [to the thirteenth power]C-NMR spectra from the structures of compounds and to…

  2. Kinetics of the reaction F+NO+M->FNO+M studied by pulse radiolysis combined with time-resolved IR and UV spectroscopy

    DEFF Research Database (Denmark)

    Pagsberg, Palle Bjørn; Sillesen, A.; Jodkowski, J.T.;

    1996-01-01

    The title reaction was initiated by pulse radiolysis of SF6/NO gas mixtures, and the formation of FNO was studied by time-resolved IR and UV spectroscopy. At SF6 pressures of 10-320 mbar at 298 K, the formation of FNO was studied by infrared diode laser spectroscopy at 1857.324 cm(-1). Comparative...

  3. Classification of edible oils and modeling of their physico-chemical properties by chemometric methods using mid-IR spectroscopy

    Science.gov (United States)

    Luna, Aderval S.; da Silva, Arnaldo P.; Ferré, Joan; Boqué, Ricard

    This research work describes two studies for the classification and characterization of edible oils and its quality parameters through Fourier transform mid infrared spectroscopy (FT-mid-IR) together with chemometric methods. The discrimination of canola, sunflower, corn and soybean oils was investigated using SVM-DA, SIMCA and PLS-DA. Using FT-mid-IR, DPLS was able to classify 100% of the samples from the validation set, but SIMCA and SVM-DA were not. The quality parameters: refraction index and relative density of edible oils were obtained from reference methods. Prediction models for FT-mid-IR spectra were calculated for these quality parameters using partial least squares (PLS) and support vector machines (SVM). Several preprocessing alternatives (first derivative, multiplicative scatter correction, mean centering, and standard normal variate) were investigated. The best result for the refraction index was achieved with SVM as well as for the relative density except when the preprocessing combination of mean centering and first derivative was used. For both of quality parameters, the best results obtained for the figures of merit expressed by the root mean square error of cross validation (RMSECV) and prediction (RMSEP) were equal to 0.0001.

  4. Biochemical Monitoring of Spinal Cord Injury by FT-IR Spectroscopy--Effects of Therapeutic Alginate Implant in Rat Models.

    Directory of Open Access Journals (Sweden)

    Sandra Tamosaityte

    Full Text Available Spinal cord injury (SCI induces complex biochemical changes, which result in inhibition of nervous tissue regeneration abilities. In this study, Fourier-transform infrared (FT-IR spectroscopy was applied to assess the outcomes of implants made of a novel type of non-functionalized soft calcium alginate hydrogel in a rat model of spinal cord hemisection (n = 28. Using FT-IR spectroscopic imaging, we evaluated the stability of the implants and the effects on morphology and biochemistry of the injured tissue one and six months after injury. A semi-quantitative evaluation of the distribution of lipids and collagen showed that alginate significantly reduced injury-induced demyelination of the contralateral white matter and fibrotic scarring in the chronic state after SCI. The spectral information enabled to detect and localize the alginate hydrogel at the lesion site and proved its long-term persistence in vivo. These findings demonstrate a positive impact of alginate hydrogel on recovery after SCI and prove FT-IR spectroscopic imaging as alternative method to evaluate and optimize future SCI repair strategies.

  5. ATR FT-IR spectroscopy on Vmh2 hydrophobin self-assembled layers for Teflon membrane bio-functionalization

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • Hydrophobin self-assembled layers on Teflon in different preparation conditions were investigated. • ATR collection data geometry allowed samples examination without any particular preparation. • Amide content, lipid/amide and carbohydrate/amide ratios of the protein layer were estimated. • Secondary structure of protein was determined for the examined samples. • FT-IR demonstrated to be of extreme relevance in monitoring hydrophobin self-assembled layers preparation. - Abstract: Surface functionalization by layers of hydrophobins, amphiphilic proteins produced by fungi offers a promising and green strategy for fabrication of biomedical and bioanalytical devices. The layering process of the Vmh2 hydrophobin from Pleurotus ostreatus on Teflon membrane has been investigated by Attenuated Total Reflection Fourier Transform Infrared (ATR FT-IR) spectroscopy. In particular, protein layers obtained with hydrophobin purified with two different procedures and in various coating conditions have been examined. The layers have been characterized by quantifying the amide I and amide II band area together with the lipid/amide ratio and carbohydrate/amide ratio. This characterization can be very useful in evaluating the best purification strategy and coating conditions. Moreover the analysis of the secondary structure of the layered protein using the deconvolution procedure of amide I band indicate the prevalent contribution from β-sheet state. The results inferred by infrared spectroscopy have been also confirmed by scanning electron microscopy imaging

  6. ATR FT-IR spectroscopy on Vmh2 hydrophobin self-assembled layers for Teflon membrane bio-functionalization

    Energy Technology Data Exchange (ETDEWEB)

    Portaccio, M., E-mail: marianna.portaccio@unina2.it [Dipartimento di Medicina Sperimentale – Seconda Università di Napoli, Via S.M. di Costantinopoli, 16-80134 Napoli (Italy); Gravagnuolo, A.M., E-mail: alfredomaria.gravagnuolo@unina.it [Dipartimento di Scienze Chimiche, Università “Federico II”, Via Cintia, 21- 80126 Napoli (Italy); Longobardi, S., E-mail: sara.longobardi@unina.it [Dipartimento di Scienze Chimiche, Università “Federico II”, Via Cintia, 21- 80126 Napoli (Italy); Giardina, P., E-mail: paola.giardina@unina.it [Dipartimento di Scienze Chimiche, Università “Federico II”, Via Cintia, 21- 80126 Napoli (Italy); Rea, I., E-mail: ilaria.rea@na.imm.cnr.it [Institute for Microelectronics and Microsystems, CNR, Via P. Castellino, 111-80131 Napoli (Italy); De Stefano, L., E-mail: luca.destefano@na.imm.cnr.it [Institute for Microelectronics and Microsystems, CNR, Via P. Castellino, 111-80131 Napoli (Italy); Cammarota, M., E-mail: marcella.cammarota@unina2.it [Dipartimento di Medicina Sperimentale – Seconda Università di Napoli, Via S.M. di Costantinopoli, 16-80134 Napoli (Italy); Lepore, M., E-mail: maria.lepore@unina2.it [Dipartimento di Medicina Sperimentale – Seconda Università di Napoli, Via S.M. di Costantinopoli, 16-80134 Napoli (Italy)

    2015-10-01

    Graphical abstract: - Highlights: • Hydrophobin self-assembled layers on Teflon in different preparation conditions were investigated. • ATR collection data geometry allowed samples examination without any particular preparation. • Amide content, lipid/amide and carbohydrate/amide ratios of the protein layer were estimated. • Secondary structure of protein was determined for the examined samples. • FT-IR demonstrated to be of extreme relevance in monitoring hydrophobin self-assembled layers preparation. - Abstract: Surface functionalization by layers of hydrophobins, amphiphilic proteins produced by fungi offers a promising and green strategy for fabrication of biomedical and bioanalytical devices. The layering process of the Vmh2 hydrophobin from Pleurotus ostreatus on Teflon membrane has been investigated by Attenuated Total Reflection Fourier Transform Infrared (ATR FT-IR) spectroscopy. In particular, protein layers obtained with hydrophobin purified with two different procedures and in various coating conditions have been examined. The layers have been characterized by quantifying the amide I and amide II band area together with the lipid/amide ratio and carbohydrate/amide ratio. This characterization can be very useful in evaluating the best purification strategy and coating conditions. Moreover the analysis of the secondary structure of the layered protein using the deconvolution procedure of amide I band indicate the prevalent contribution from β-sheet state. The results inferred by infrared spectroscopy have been also confirmed by scanning electron microscopy imaging.

  7. Accelerated Aging of BKC 44306-10 Rigid Polyurethane Foam: FT-IR Spectroscopy, Dimensional Analysis, and Micro Computed Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Gilbertson, Robert D. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Patterson, Brian M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Smith, Zachary [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-01-02

    An accelerated aging study of BKC 44306-10 rigid polyurethane foam was carried out. Foam samples were aged in a nitrogen atmosphere at three different temperatures: 50 °C, 65 °C, and 80 °C. Foam samples were periodically removed from the aging canisters at 1, 3, 6, 9, 12, and 15 month intervals when FT-IR spectroscopy, dimensional analysis, and mechanical testing experiments were performed. Micro Computed Tomography imaging was also employed to study the morphology of the foams. Over the course of the aging study the foams the decreased in size by a magnitude of 0.001 inches per inch of foam. Micro CT showed the heterogeneous nature of the foam structure likely resulting from flow effects during the molding process. The effect of aging on the compression and tensile strength of the foam was minor and no cause for concern. FT-IR spectroscopy was used to follow the foam chemistry. However, it was difficult to draw definitive conclusions about the changes in chemical nature of the materials due to large variability throughout the samples.

  8. Post-Starburst Populations Near and Far - The Potential of Near-IR Spectroscopy

    CERN Document Server

    Lançon, A

    2000-01-01

    The efficient use of near-IR data in studies of external stellar populations depends on our ability to recognize the nature of the predominant sources of light, and to interprete these findings in terms of age and metallicity. Here we focus on elderly post-starburst populations, with ages of 0.1-1 Gyr. New models confirm that they are indeed expected to display specific spectral signatures in the near-IR, due to variable M stars of the asymptotic giant branch and to carbon stars. The signatures depend on age and metallicity. We summarize the status of current quantitative predictions and emphasize the importance of an empirical calibration of the spectral synthesis models.

  9. Recent applications of vibrational mid-Infrared (IR spectroscopy for studying soil components: a review

    Directory of Open Access Journals (Sweden)

    Anna Tinti

    2015-03-01

    Full Text Available The present review highlights the recent applications of mid-infrared spectroscopy and in particular of diffuse reflectance spectroscopy (DRIFT and attenuated total reflectance (ATR and processing methods (e.g., deconvolution, derivative and chemometrics to rapidly provide valuable information on soil composition and organic geochemistry. Research has demonstrated that both DRIFT and ATR techniques can be considered useful tools for the analysis of a large number of soil samples, giving not only typical spectral patterns but permitting an accurate prediction of quantitative parameters such as, e.g., total carbon, total nitrogen, C/N ratio, lignin, dissolved OC, carbonyl-C, aromatic-C, O-alkyl-C, and alkyl-C contents. Based on literature results, infrared spectroscopy can be recognized as one of the most promising analytical techniques for investigating soil science.

  10. Compact large-aperture Fabry-Perot interferometer modules for gas spectroscopy at mid-IR

    Science.gov (United States)

    Kantojärvi, Uula; Varpula, Aapo; Antila, Tapani; Holmlund, Christer; Mäkynen, Jussi; Näsilä, Antti; Mannila, Rami; Rissanen, Anna; Antila, Jarkko; Disch, Rolf J.; Waldmann, Torsten A.

    2014-03-01

    VTT has developed Fabry-Pérot Interferometers (FPI) for visible and infrared wavelengths since 90's. Here we present two new platforms for mid-infrared gas spectroscopy having a large optical aperture to provide high optical throughput but still enabling miniaturized instrument size. First platform is a tunable filter that replaces a traditional filter wheel, which operates between wavelengths of 4-5 um. Second platform is for correlation spectroscopy where the interferometer provides a comb-like transmission pattern mimicking absorption of diatomic molecules at the wavelength range of 4.7-4.8 um. The Bragg mirrors have 2-4 thin layers of polysilicon and silicon oxide.

  11. Ultrafast IR Spectroscopy on Aqueous Reverse-Micellar Nano-Droplets

    NARCIS (Netherlands)

    Cringus, Dan; Milder, Maaike T.W.; Pshenichnikov, Maxim S.; Wiersma, Douwe A.; Lindner, Jörg; Vöhringer, Peter; Kobayashi, Takayoshi; Kobayashi, Tetsuro; Nelson, Keith A.; Okada, Tadashi; Silvestri, Sandro De

    2005-01-01

    The ultrafast dynamics of water nano-droplets (1-10 nm size) of the L2-phase of the ternary mixture H2O-AOT-CCl4 have been studied using frequency-resolved mid-infrared pump-probe spectroscopy in the spectral region of the OH-stretching vibration.

  12. Chemical Sensors Based on IR Spectroscopy and Surface-Modified Waveguides

    Science.gov (United States)

    Lopez, Gabriel P.; Niemczyk, Thomas

    1999-01-01

    Sol-gel processing techniques have been used to apply thin porous films to the surfaces of planar infrared (IR) waveguides to produce widely useful chemical sensors. The thin- film coating serves to diminish the concentration of water and increase the concentration of the analyte in the region probed by the evanescent IR wave. These porous films are composed of silica, and therefore, conventional silica surface modification techniques can be used to give the surface a specific functional character. The sol-gel film was surface-modified to make the film highly hydrophobic. These sensors were shown to be capable of detecting non-polar organic analytes, such as benzonitrile, in aqueous solution with detection limits in the ppb range. Further, these porous sol-gel structures allow the analytes to diffuse into and out of the films rapidly, thus reaching equilibrium in less than ten seconds. These sensors are unique because of the fact that their operation is based on the measurement of an IR absorption spectrum. Thus, these sensors are able to identify the analytes as well as measure concentration with high sensitivity. These developments have been documented in previous reports and publications. Recently, we have also targeted detection of the polar organic molecules acetone and isopropanol in aqueous solution. Polar organics are widely used in industrial and chemical processes, hence it is of interest to monitor their presence in effluents or decontamination process flows. Although large improvements in detection limits were expected with non-polar organic molecules in aqueous solutions using very hydrophobic porous sol-gel films on silicon attenuated total reflectance (Si ATR) waveguides, it was not as clear what the detection enhancements might be for polar organic molecules. This report describes the use of modified sol-gel-coated Si ATR sensors for trace detection and quantitation of small polar organic molecules in aqueous solutions. The detection of both acetone

  13. Activation and deactivation of a robust immobilized Cp*Ir-transfer hydrogenation catalyst: a multielement in situ X-ray absorption spectroscopy study.

    Science.gov (United States)

    Sherborne, Grant J; Chapman, Michael R; Blacker, A John; Bourne, Richard A; Chamberlain, Thomas W; Crossley, Benjamin D; Lucas, Stephanie J; McGowan, Patrick C; Newton, Mark A; Screen, Thomas E O; Thompson, Paul; Willans, Charlotte E; Nguyen, Bao N

    2015-04-01

    A highly robust immobilized [Cp*IrCl2]2 precatalyst on Wang resin for transfer hydrogenation, which can be recycled up to 30 times, was studied using a novel combination of X-ray absorption spectroscopy (XAS) at Ir L3-edge, Cl K-edge, and K K-edge. These culminate in in situ XAS experiments that link structural changes of the Ir complex with its catalytic activity and its deactivation. Mercury poisoning and "hot filtration" experiments ruled out leached Ir as the active catalyst. Spectroscopic evidence indicates the exchange of one chloride ligand with an alkoxide to generate the active precatalyst. The exchange of the second chloride ligand, however, leads to a potassium alkoxide-iridate species as the deactivated form of this immobilized catalyst. These findings could be widely applicable to the many homogeneous transfer hydrogenation catalysts with Cp*IrCl substructure. PMID:25768298

  14. Following [FeFe] Hydrogenase Active Site Intermediates by Time-Resolved Mid-IR Spectroscopy.

    Science.gov (United States)

    Mirmohades, Mohammad; Adamska-Venkatesh, Agnieszka; Sommer, Constanze; Reijerse, Edward; Lomoth, Reiner; Lubitz, Wolfgang; Hammarström, Leif

    2016-08-18

    Time-resolved nanosecond mid-infrared spectroscopy is for the first time employed to study the [FeFe] hydrogenase from Chlamydomonas reinhardtii and to investigate relevant intermediates of the enzyme active site. An actinic 355 nm, 10 ns laser flash triggered photodissociation of a carbonyl group from the CO-inhibited state Hox-CO to form the state Hox, which is an intermediate of the catalytic proton reduction cycle. Time-resolved infrared spectroscopy allowed us to directly follow the subsequent rebinding of the carbonyl, re-forming Hox-CO, and determine the reaction half-life to be t1/2 ≈ 13 ± 5 ms at room temperature. This gives direct information on the dynamics of CO inhibition of the enzyme. PMID:27494400

  15. Following [FeFe] Hydrogenase Active Site Intermediates by Time-Resolved Mid-IR Spectroscopy.

    Science.gov (United States)

    Mirmohades, Mohammad; Adamska-Venkatesh, Agnieszka; Sommer, Constanze; Reijerse, Edward; Lomoth, Reiner; Lubitz, Wolfgang; Hammarström, Leif

    2016-08-18

    Time-resolved nanosecond mid-infrared spectroscopy is for the first time employed to study the [FeFe] hydrogenase from Chlamydomonas reinhardtii and to investigate relevant intermediates of the enzyme active site. An actinic 355 nm, 10 ns laser flash triggered photodissociation of a carbonyl group from the CO-inhibited state Hox-CO to form the state Hox, which is an intermediate of the catalytic proton reduction cycle. Time-resolved infrared spectroscopy allowed us to directly follow the subsequent rebinding of the carbonyl, re-forming Hox-CO, and determine the reaction half-life to be t1/2 ≈ 13 ± 5 ms at room temperature. This gives direct information on the dynamics of CO inhibition of the enzyme.

  16. Studies of Eu2O3 - Bi2O3 - B2O3 glasses using Raman and IR spectroscopy

    International Nuclear Information System (INIS)

    The bismuth borate (3Bi2O3·B2O3) glasses were prepared with different concentrations of Eu3+. The structure of these systems were investigated by Raman and IR spectroscopy. The structural study reveals that the glasses contain BiO3, BiO6, BO3, BO4 and Eu-O structural units. For the samples with a higher content of Eu2O3, the spectra became very large indicating a more disordered structure. The hygroscopic character of the 3Bi2O3·B2O3 glass matrix and the progressive decrease of this behaviour with increasing the Eu2O3 content was observed. Therefore, we conclude that the europium oxide acts as a network modifier in these glasses. (authors)

  17. Impact of Humidity on Quartz-Enhanced Photoacoustic Spectroscopy Based CO Detection Using a Near-IR Telecommunication Diode Laser.

    Science.gov (United States)

    Yin, Xukun; Dong, Lei; Zheng, Huadan; Liu, Xiaoli; Wu, Hongpeng; Yang, Yanfang; Ma, Weiguang; Zhang, Lei; Yin, Wangbao; Xiao, Liantuan; Jia, Suotang

    2016-01-01

    A near-IR CO trace gas sensor based on quartz-enhanced photoacoustic spectroscopy (QEPAS) is evaluated using humidified nitrogen samples. Relaxation processes in the CO-N2-H2O system are investigated. A simple kinetic model is used to predict the sensor performance at different gas pressures. The results show that CO has a ~3 and ~5 times slower relaxation time constant than CH4 and HCN, respectively, under dry conditions. However, with the presence of water, its relaxation time constant can be improved by three orders of magnitude. The experimentally determined normalized detection sensitivity for CO in humid gas is 1.556 × 10(-8) W ⋅ cm (-1)/Hz(1/2).

  18. Selective modification of polylactide by introducing acrylate groups: IR spectroscopy, gel permeation chromatography, and differential thermal analysis

    Science.gov (United States)

    Shashkova, V. T.; Matveeva, I. A.; Glagolev, N. N.; Zarkhina, T. S.; Timashev, P. S.; Bagratashvili, V. N.; Solov'eva, A. B.

    2016-10-01

    One-stage modification of polylactide has been performed to obtain the acrylate derivatives of the polymer capable of further polymerization and preparation of cross-linked polymer materials suitable for creating implants. The reaction mechanism was determined by IR spectroscopy, gel permeation chromatography, and differential thermal analysis. It was shown for the first time that the reaction path changes depending on the ratio of components so that the desired product polylactide acrylate forms with a ~90% yield only in the presence of large (approximately tenfold) excesses of the isocyanate and acrylate components; at the equimolar ratio of components generally used in urethane formation, a mixture of the desired product (~30%), oligourethane diacrylates, and unchanged polylactide forms.

  19. Nitriles as directionally tolerant hydrogen bond acceptors: IR-UV ion depletion spectroscopy of benzenepropanenitrile and its hydrate clusters

    Science.gov (United States)

    Robertson, Patrick A.; Lobo, Isabella A.; Wilson, David J. D.; Robertson, Evan G.

    2016-09-01

    Benzenepropanenitrile (BPN) and its hydrate clusters are studied by R2PI and IR-UV ion-depletion spectroscopy in the CH/OH stretch regions, aided by theoretical calculations. A single water molecule binds to the terminal nitrile 'lone-pair' of the anti-BPN host, but there is also evidence for a side-type structure with OH donating to the nitrile π-electrons. In the gauche-BPN cluster, water is located at an intermediate angle that facilitates O⋯HC(ortho) interaction. A wide range of attachment angles is possible, as the intrinsic preference for linear hydrogen bonding is mediated by additional CH⋯O interactions that depend on molecular geometry near the nitrile group.

  20. Impact of Humidity on Quartz-Enhanced Photoacoustic Spectroscopy Based CO Detection Using a Near-IR Telecommunication Diode Laser

    Directory of Open Access Journals (Sweden)

    Xukun Yin

    2016-01-01

    Full Text Available A near-IR CO trace gas sensor based on quartz-enhanced photoacoustic spectroscopy (QEPAS is evaluated using humidified nitrogen samples. Relaxation processes in the CO-N2-H2O system are investigated. A simple kinetic model is used to predict the sensor performance at different gas pressures. The results show that CO has a ~3 and ~5 times slower relaxation time constant than CH4 and HCN, respectively, under dry conditions. However, with the presence of water, its relaxation time constant can be improved by three orders of magnitude. The experimentally determined normalized detection sensitivity for CO in humid gas is 1.556 × 10 − 8   W ⋅ cm − 1 / Hz 1 / 2 .

  1. Vibrational structure of C 84 and Sc 2@C 84 analyzed by IR spectroscopy

    Science.gov (United States)

    Hulman, M.; Pichler, T.; Kuzmany, H.; Zerbetto, F.; Yamamoto, E.; Shinohara, H. N.

    1997-06-01

    The isomer III of Sc 2@C 84 was separated by multi-cycle HPLC purification. We present temperature dependent IR absorption measurements of Sc 2@C 84 which have been performed between 50 and 300 K and between 400 and 5000 cm -1, respectively. The vibrational structure of the endohedral compound is compared to the structure of unfilled C 84. We find a strong overall broadening of the vibrational modes in Sc 2@C 84. Also some of the vibrational absorption lines are strongly enhanced if compared to the spectrum for the empty cage. With decreasing temperature, a dramatic narrowing of the lines in the spectral range between 700 and 800 cm -1 is observed.

  2. High-resolution IR absorption spectroscopy of polycyclic aromatic hydrocarbons: the realm of anharmonicity

    CERN Document Server

    Maltseva, Elena; Candian, Alessandra; Mackie, Cameron J; Huang, Xinchuan; Lee, Timothy J; Tielens, Alexander G G M; Oomens, Jos; Buma, Wybren Jan

    2015-01-01

    We report on an experimental and theoretical investigation of the importance of anharmonicity in the 3 micron CH stretching region of Polycyclic Aromatic Hydrocarbon (PAH) molecules. We present mass-resolved, high-resolution spectra of the gas-phase cold (~4K) linear PAH molecules naphthalene, anthracene, and tetracene. The measured IR spectra show a surprisingly high number of strong vibrational bands. For naphthalene, the observed bands are well separated and limited by the rotational contour, revealing the band symmetries. Comparisons are made to the harmonic and anharmonic approaches of the widely used Gaussian software. We also present calculated spectra of these acenes using the computational program SPECTRO, providing anharmonic predictions enhanced with a Fermi-resonance treatment that utilises intensity redistribution. We demonstrate that the anharmonicity of the investigated acenes is strong, dominated by Fermi resonances between the fundamental and double combination modes, with triple combination ...

  3. Detection of no and S-Nitrosocompounds Using Mid-Ir Cavity Ring-Down Spectroscopy

    Science.gov (United States)

    Stsiapura, Vitali; Shuali, Vincent K.; Ziegler, Angela; Lehmann, Kevin K.; Gaston, Benjamin M.

    2013-06-01

    Metabolic reactions of S-nitrosothiols have received much attention in biochemistry and medicine since S-nitrosocompounds can act not only as donors of nitric oxide (NO) in an organism but can themselves be involved in signal transduction. In the past few decades, the primary means of detecting S-nitrosocompounds in biological media has been through chemiluminescence detection of NO, a technique that limits the sensitivity to ppb levels and is not able to trace isotopologues of NO. Here we present a cw-CRD instrument for detection of NO isotopologues released from S-nitrosocompounds with a sensitivity of 27 pptv of NO in 100 torr He (after averaging of ˜400 ringdowns). A mid-IR ec-QCL laser (Daylight Solutions) is used to excite the ringdown cavity of finesse ˜10000 and probe the NO fundamental ro-vibrational band in the 5.2 - 5.3 μm range.

  4. A Concept for Seeing-Limited Near-IR Spectroscopy on the Giant Magellan Telescope

    Science.gov (United States)

    Simcoe, Robert A.; Furesz, Gabor; Egan, Mark; Malonis, Andrew; Hellickson, Tim

    2016-09-01

    We present a simple seeing-limited IR spectrometer design for the Giant Magellan Telescope, with continuous R = 6000 coverage from 0.87-2.50 microns for a 0:7" slit. The instrument's design is based on an asymmetric white pupil echelle layout, with dichroics splitting the optical train into yJ, H, and K channels after the pupil transfer mirror. A separate low-dispersion mode offers single-object R ~ 850 spectra which also cover the full NIR bandpass in each exposure. Catalog gratings and H2RG detectors are used to minimize cost, and only two cryogenic rotary mechanisms are employed, reducing mechanical complexity. The instrument dewar occupies an envelope of 1:8×1:5×1:2 meters, satisfying mass and volume requirements for GMT with comfortable margin. We estimate the system throughput at ~35% including losses from the atmosphere, telescope, and instrument (i.e. all coatings, gratings, and sensors). This optical efficiency is comparable to the FIRE spectrograph on Magellan, and we have specified and designed fast cameras so the GMT instrument will have an almost identical pixel scale as FIRE. On the 6.5 meter Magellan telescopes, FIRE is read-noise limited in the y and J bands, similar to other existing near-IR spectrometers and also to JWST/NIRSPEC. GMT's twelve-fold increase in collecting area will therefore offer gains in signal-to-noise per exposure that exceed those of moderate resolution optical instruments, which are already sky-noise limited on today's telescopes. Such an instrument would allow GMT to pursue key early science programs on the Epoch of Reionization, galaxy formation, transient astronomy, and obscured star formation environments prior to commissioning of its adaptive optics system. This design study demonstrates the feasibility of developing relatively affordable spectrometers at the ELT scale, in response to the pressures of joint funding for these telescopes and their associated instrument suites.

  5. Rapid Quantitative Determination of Squalene in Shark Liver Oils by Raman and IR Spectroscopy.

    Science.gov (United States)

    Hall, David W; Marshall, Susan N; Gordon, Keith C; Killeen, Daniel P

    2016-01-01

    Squalene is sourced predominantly from shark liver oils and to a lesser extent from plants such as olives. It is used for the production of surfactants, dyes, sunscreen, and cosmetics. The economic value of shark liver oil is directly related to the squalene content, which in turn is highly variable and species-dependent. Presented here is a validated gas chromatography-mass spectrometry analysis method for the quantitation of squalene in shark liver oils, with an accuracy of 99.0 %, precision of 0.23 % (standard deviation), and linearity of >0.999. The method has been used to measure the squalene concentration of 16 commercial shark liver oils. These reference squalene concentrations were related to infrared (IR) and Raman spectra of the same oils using partial least squares regression. The resultant models were suitable for the rapid quantitation of squalene in shark liver oils, with cross-validation r (2) values of >0.98 and root mean square errors of validation of ≤4.3 % w/w. Independent test set validation of these models found mean absolute deviations of the 4.9 and 1.0 % w/w for the IR and Raman models, respectively. Both techniques were more accurate than results obtained by an industrial refractive index analysis method, which is used for rapid, cheap quantitation of squalene in shark liver oils. In particular, the Raman partial least squares regression was suited to quantitative squalene analysis. The intense and highly characteristic Raman bands of squalene made quantitative analysis possible irrespective of the lipid matrix.

  6. Sensing the Structural Differences in Cellulose from Apple and Bacterial Cell Wall Materials by Raman and FT-IR Spectroscopy

    Directory of Open Access Journals (Sweden)

    Artur Zdunek

    2011-05-01

    Full Text Available Raman and Fourier Transform Infrared (FT-IR spectroscopy was used for assessment of structural differences of celluloses of various origins. Investigated celluloses were: bacterial celluloses cultured in presence of pectin and/or xyloglucan, as well as commercial celluloses and cellulose extracted from apple parenchyma. FT-IR spectra were used to estimate of the Iβ content, whereas Raman spectra were used to evaluate the degree of crystallinity of the cellulose. The crystallinity index (XCRAMAN% varied from −25% for apple cellulose to 53% for microcrystalline commercial cellulose. Considering bacterial cellulose, addition of xyloglucan has an impact on the percentage content of cellulose Iβ. However, addition of only xyloglucan or only pectins to pure bacterial cellulose both resulted in a slight decrease of crystallinity. However, culturing bacterial cellulose in the presence of mixtures of xyloglucan and pectins results in an increase of crystallinity. The results confirmed that the higher degree of crystallinity, the broader the peak around 913 cm−1. Among all bacterial celluloses the bacterial cellulose cultured in presence of xyloglucan and pectin (BCPX has the most similar structure to those observed in natural primary cell walls.

  7. Thermal decomposition of methyl 2-azidopropionate studied by UV photoelectron spectroscopy and matrix isolation IR spectroscopy: heterocyclic intermediate vs imine formation.

    Science.gov (United States)

    Pinto, R M; Dias, A A; Costa, M L; Rodrigues, P; Barros, M T; Ogden, J S; Dyke, J M

    2011-08-01

    Methyl 2-azidopropionate (N(3)CH(3)CHCOOCH(3), M2AP) has been synthesized and characterized by different spectroscopic methods, and the thermal decomposition of this molecule has been investigated by matrix isolation infrared (IR) spectroscopy and ultraviolet photoelectron spectroscopy (UVPES). Computational methods have been employed in the spectral simulation of both UVPES and matrix IR spectra and in the rationalization of the thermal decomposition results. M2AP presents a HOMO vertical ionization energy (VIE) of 9.60 ± 0.03 eV and contributions from all four lowest-energy conformations of this molecule are detected in the gas phase. Its thermal decomposition starts at ca. 400 °C and is complete at ca. 650 °C, yielding N(2), CO, CO(2), CH(3)CN, and CH(3)OH as the final decomposition products. Methyl formate (MF) and CH(4) are also found during the pyrolysis process. Analysis of the potential energy surface of the decomposition of M2AP indicates that M2AP decomposes preferentially into the corresponding imine (M2IP), through a 1,2-H shift synchronous with the N(2) elimination (Type 1 mechanism), requiring an activation energy of 160.8 kJ/mol. The imine further decomposes via two competitive routes: one accounting for CO, CH(3)OH, and CH(3)CN (ΔE(G3) = 260.2 kJ/mol) and another leading to CO(2), CH(4), and CH(3)CN (ΔE(G3) = 268.6 kJ/mol). A heterocyclic intermediate (Type 2 mechanism)-4-Me-5-oxazolidone-can also be formed from M2AP via H transfer from the remote O-CH(3) group, together with the N(2) elimination (ΔE(G3) = 260.2 kJ/mol). Finally, a third pathway which accounts for the formation of MF through an M2AP isomer is envisioned.

  8. INVESTIGATION OF RADIUM ORTHOSILICATES BY METHODS OF FT-IR SPECTROSCOPY AND DERIVATOGRAPHY

    OpenAIRE

    Garibov, Adil; Agayev, Teymur; Mansimov, Zaur; Melikova, Sevinj; Eyubov, Kerim

    2014-01-01

    Synthesized radium orthosilicates with various concentrations of radium and activity of samples were researched by methods of infrared spectroscopy and derivatography. There was researched a change of relative optic densities of absorption bonds of stretching vibrations RaO and Si-O bonds and Si-O2 tetrahedrons with maximums at 930 and 960cm-1 dependent on radium weight concentration. In this case maximal specific activity of bound radium is 2500Bk/g. According to DTA-analysis, RaO·Si-O2·2H2O...

  9. FT-IR Photoacoustic Spectroscopy Applied to the Curing and Aging of Composites

    Science.gov (United States)

    Jones, Roger W.; Sweterlitsch, Jeffrey J.; Wagner, Anthony J.; McClelland, John F.; Hsu, David K.; Polis, Daniel L.; Sovinski, Marjorie F.

    2005-04-01

    Fourier-transform infrared photoacoustic spectroscopy has been applied to carbon-fiber composites to test whether bulk physical properties of the composites could be determined using the near-surface-sensitive photoacoustic approach. Both the cure levels of carbon fiber/cyanate ester composites and the interlaminar shear strengths of artificially aged carbon fiber/epoxy composites were successfully measured. Standard errors of cross validation were 3.46% cure for a sample set ranging from 8% to 95% cured and 1.60 MPa for aged samples with strengths ranging from 22 to 77 MPa.

  10. IR-spectroscopy as an analytical method for identification of horticultural peat

    International Nuclear Information System (INIS)

    The process of selecting different peat types for horticultural purposes involves many physical and chemical determinations. Infrared spectroscopy could be used together with the usual methods for the evaluation of peat quality. Due to the fact that different peats contain different amounts of infrared absorbing functional groups, each peat produces a characteristic spectrum. From the spectrum, one may determine the botanical composition, degree of humification, ash content, cation exchange capacity, nitrogen content and carbon content, of the natural peat. The spectrum also shows whether the peat has been fertilized and limed and in some cases the presence of mineral soil or wetting agent mixed in the peat may be detected

  11. GEL-STATE NMR OF BALL-MILLED WHOLE CELL WALLS IN DMSO-d6 USING 2D SOLUTION-STATE NMR SPECTROSCOPY

    Science.gov (United States)

    Plant cell walls were used for obtaining 2D solution-state NMR spectra without actual solubilization or structural modification. Ball-milled whole cell walls were swelled directly in the NMR tube with DMSO-d6 where they formed a gel. There are relatively few gel-state NMR studies. Most have involved...

  12. Synthesis and Resolution of the Atropisomeric 1,1'-Bi-2-Naphthol: An Experiment in Organic Synthesis and 2-D NMR Spectroscopy

    Science.gov (United States)

    Mak, Kendrew K. W.

    2004-01-01

    NMR spectroscopy is presented. It is seen that the experiment regarding the synthesis and resolution of 1,1'-Bi-2-naphtol presents a good experiment for teaching organic synthesis and NMR spectroscopy and provides a strategy for obtaining enantiopure compounds from achiral starting materials.

  13. Investigation of trap levels in HgCdTe IR detectors through low frequency noise spectroscopy

    International Nuclear Information System (INIS)

    Low frequency noise spectroscopy is a valuable tool for studying narrow gap semiconductor materials and devices. In the paper, the method of traps investigation with low frequency noise spectroscopy was presented, together with quantitative analysis of the results obtained for high-operating-temperature, fast response, Hg1−xCdxTe mid-wavelength infrared detectors. The hole trap levels in these devices are Cd-content independent and take the value E T ≅ 140 meV or E T ≅ 40 meV. The level at E T ≅ 140 meV was found for almost all tested detectors. The level around E T = 40 meV was found in two samples. Apart from the hole traps, three electron traps were also found. Their energy levels follow the trend lines E T = 0.35E g(x) and E T = 0.75E g(x). All trap energies are consistent with the results reported in the literature for Hg1−xCdxTe devices. (paper)

  14. Spatially Resolved Spitzer-IRS Spectroscopy of the Central Region of M82

    CERN Document Server

    Beirão, P; Appleton, P N; Groves, B; Armus, L; Förster-Schreiber, N M; Smith, J D; Charmandaris, V; Houck, J R

    2007-01-01

    We present high spatial resolution (~ 35 parsec) 5-38 um spectra of the central region of M82, taken with the Spitzer Infrared Spectrograph. From these spectra we determined the fluxes and equivalent widths of key diagnostic features, such as the [NeII]12.8um, [NeIII]15.5um, and H_2 S(1)17.03um lines, and the broad mid-IR polycyclic aromatic hydrocarbon (PAH) emission features in six representative regions and analysed the spatial distribution of these lines and their ratios across the central region. We find a good correlation of the dust extinction with the CO 1-0 emission. The PAH emission follows closely the ionization structure along the galactic disk. The observed variations of the diagnostic PAH ratios across M82 can be explained by extinction effects, within systematic uncertainties. The 16-18um PAH complex is very prominent, and its equivalent width is enhanced outwards from the galactic plane. We interpret this as a consequence of the variation of the UV radiation field. The EWs of the 11.3um PAH fe...

  15. High-Resolution IR Absorption Spectroscopy of Polycyclic Aromatic Hydrocarbons: The Realm of Anharmonicity

    Science.gov (United States)

    Maltseva, Elena; Petrignani, Annemieke; Candian, Alessandra; Mackie, Cameron J.; Huang, Xinchuan; Lee, Timothy J.; Tielens, Alexander G. G. M.; Oomens, Jos; Buma, Wybren Jan

    2016-01-01

    We report on an experimental and theoretical investigation of the importance of anharmonicity in the 3 micrometers CH stretching region of Polycyclic Aromatic Hydrocarbon (PAH) molecules. We present mass-resolved, high-resolution spectra of the gas-phase cold ((is) approximately 4K) linear PAH molecules naphthalene, anthracene, and tetracene. The measured IR spectra show a surprisingly high number of strong vibrational bands. For naphthalene, the observed bands are well separated and limited by the rotational contour, revealing the band symmetries. Comparisons are made to the harmonic and anharmonic approaches of the widely used Gaussian software. We also present calculated spectra of these acenes using the computational program SPECTRO, providing anharmonic predictions enhanced with a Fermi-resonance treatment that utilizes intensity redistribution. We demonstrate that the anharmonicity of the investigated acenes is strong, dominated by Fermi resonances between the fundamental and double combination modes, with triple combination bands as possible candidates to resolve remaining discrepancies. The anharmonic spectra as calculated with SPECTRO lead to predictions of the main modes that fall within 0.5% of the experimental frequencies. The implications for the Aromatic Infrared Bands, specifically the 3-m band are discussed.

  16. Chemical curing in alkyd paints: An evaluation via FT-IR and NMR spectroscopies

    Science.gov (United States)

    Bartolozzi, G.; Marchiafava, V.; Mirabello, V.; Peruzzini, M.; Picollo, M.

    2014-01-01

    A study aimed at determining the time necessary for an alkyd paint to attain chemical curing is presented. In particular, the object of our investigation was an oil paint made by Winsor & Newton, namely French ultramarine (PB29) in the Griffin Alkyd “fast drying oil colour” series. Using this paint, we prepared several mock-ups on glass. These were left in the laboratory at room temperature in a piece of furniture with glass doors for a total of 70 days. Samples were taken at different times, and the changes in their composition were monitored by means of FT-IR and multinuclear NMR spectroscopic analyses. Since the cross-linking reactions involved in the formation of the pictorial film mainly affect the amount of carbon-carbon double bonds, we monitored the decrease in allyl, diallyl and vinyl protons and carbons. The data obtained from the use of both techniques led us to conclude that, in our particular experimental conditions, the chemical curing of the paint layer is reached within the first 70 days, thus establishing the beginning of the ageing phenomena.

  17. High Spatial Resolution Spectroscopy of W51 IRS2E and IRS2W: Two Very Massive Young Stars in Early Formation Stages

    CERN Document Server

    Barbosa, C L; Conti, P S; Damineli, A; Figueredo, E

    2008-01-01

    We present $K$-band spectra of the near infrared counterparts to IRS2E and IRS2W which is associated with the ultracompact HII region W51d, both of them embedded sources in the Galactic compact HII region W51 IRS2. The high spatial resolution observations were obtained with the laser guide star facility and Near infrared Integral Field Spectrograph (NIFS) mounted at the Gemini North observatory. The spectrum of the ionizing source of W51d shows the photospheric features NIII (21155 \\AA) in emission and HeII (21897 \\AA) in absorption which lead us to classify it as an young O3 type star. We detected CO overtone in emission at 23000 \\AA in the spectrum of IRS2E, suggesting that it is a massive young object still surrounded by an accretion disc, probably transitioning from the hot core phase to an ultracompact HII region.

  18. Carbonization and demineralization of coals: A study by means of FT–IR spectroscopy

    Indian Academy of Sciences (India)

    V Gómez-Serrano; M C Fernández-González; M L Rojas-Cervantes; M F Alexandre-Franco; A Macías-García

    2003-12-01

    Coal basically consists of two parts-a crystalline, inorganic part, and an amorphous, organic part. Based on this, we intended to study the changes that occurred on the composition and on the chemical structure of coals after carbonization at 1000 or 900°C and demineralization treatments with hydrochloric and hydrofluoric acids. For this, four coals of different categories (or levels) were chosen: semianthracite (A–O) and high volatile bituminous coal (B–O), which are high level coals, and lignite (Li–O) and leonardite (Le–O), these being low level coals. The coals were first analysed in terms of their proximate and elemental compositions and then carbonized and demineralized. Also, the starting coals and the prepared samples were examined by infrared spectroscopy. In addition, a study of the optimization of the application of this technique for only A–O was carried out. For A–O and B–O, the spectra recorded intense absorption bands that are ascribable to vibration modes in mineral components as quartz and aluminosilicates, such as kaolinite. For Li–O and Le–O, the spectra displayed some other bands as well, also quite intense, which have been assigned to bond vibrations in functional groups and structures of their organic part. The carbonization of the coals resulted in significant changes in their inorganic part as the content of quartz increased and the content of aluminosilicates decreased. In addition, the thermal decomposition of mineral carbonates occurred. The carbonization greatly affects the organic part of the coals, especially in Li–O and Le–O, as most functional groups and structures are not thermally stable under heating conditions. With regard to demineralization, HF is a more effective agent than HCl, achieving products with higher organic content. The mass losses are higher in Li–O and Le–O than in A–O and B–O. So, the infrared spectroscopy allows the analysis of both inorganic and organic parts of the coals and of

  19. Qualitative application based on IR spectroscopy for bone sample quality control in radiocarbon dating

    International Nuclear Information System (INIS)

    Bone samples suffer from contamination and deterioration, depending on their conservation state and previous restoration and consolidation processes. The sample preparation laboratory of the CEDAD (Center for Dating and Diagnostics) of University of Lecce is developing a quality control protocol for bone samples based on Fourier transform infrared (FTIR) spectroscopy to identify the presence of collagen in bone samples and to assess its quality. FTIR measurements were carried out on collagen extracted from many ancient samples dated at CEDAD. Efforts to shift the FTIR quality control test from the filtration step to a check-in treatment are proceeding to optimize the time for preparation and to reduce the overall turnaround time. A standard fast demineralization treatment was set up and applied to a variety of ancient samples of different origin and age

  20. Qualitative application based on IR spectroscopy for bone sample quality control in radiocarbon dating

    Science.gov (United States)

    Gianfrate, G.; D'Elia, M.; Quarta, G.; Giotta, L.; Valli, L.; Calcagnile, L.

    2007-06-01

    Bone samples suffer from contamination and deterioration, depending on their conservation state and previous restoration and consolidation processes. The sample preparation laboratory of the CEDAD (Center for Dating and Diagnostics) of the University of Lecce is developing a quality control protocol for bone samples based on Fourier transform infrared (FTIR) spectroscopy to identify the presence of collagen in bone samples and to assess its quality. FTIR measurements were carried out on collagen extracted from many ancient samples dated at CEDAD. Efforts to shift the FTIR quality control test from the filtration step to a check-in treatment are proceeding to optimize the time for preparation and to reduce the overall turnaround time. A standard fast demineralization treatment was set up and applied to a variety of ancient samples of different origin and age.

  1. Action spectroscopy of gas-phase carboxylate anions by multiple photon IR electron detachment/attachment

    CERN Document Server

    Steill, Jeffrey D

    2008-01-01

    We report on a form of gas-phase anion action spectroscopy based on infrared multiple photon electron detachment and subsequent capture of the free electrons by a neutral electron scavenger in a Fourier Transform Ion Cyclotron Resonance (FTICR) mass spectrometer. This method allows one to obtain background-free spectra of strongly bound anions, for which no dissociation channels are observed. The first gas-phase spectra of the acetate and propionate anions are presented using SF6 as electron scavenger and a free electron laser as source of intense and tunable infrared radiation. To validate the method, we compare infrared spectra obtained through multiple photon electron detachment/attachment and multiple photon dissociation for the benzoate anion. In addition, different electron acceptors are used, comparing both associative and dissociative electron capture. The relative energies of dissociation (by CO2 loss) and electron detachment are investigated for all three anions by DFT and CCSD(T) methods. DFT calcu...

  2. Endohedral fullerenes: a concurrent characterization by means of synchrotron radiation X-ray and IR spectroscopy

    Science.gov (United States)

    Xu, Wei; Marcelli, Augusto; Liu, Lei; Wang, Chunru; Wu, Ziyu

    2013-04-01

    Endohedral Metal Fullerenes exhibit a great variety of physical and chemical properties depending on the metal inserted into the cage. These systems are molecular conductors, magnets, ferroelectrics and also superconductors representing extremely promising materials for advanced technologies such as nano-medicine. Here we present temperature-dependent XANES and FTIR investigations of two La@C82 EMF isomers. The combinatorial investigation shows that guest ions move inside the cage perturbing the vibrational states of the carbon cage due to the charge transfer dynamics. Moreover, the principal component analysis points out a discrepancy between temperature-dependent FTIR and XANES based on the occurrence of a non-equilibrium process between charge transfer and cage dynamics. We propose to perform simultaneous time-resolved X-ray and infrared spectroscopy studies to resolve the complex interplay among charge, structure and electric properties of these systems.

  3. UV and IR spectroscopy of cold 1,2-dimethoxybenzene complexes with alkali metal ions.

    Science.gov (United States)

    Inokuchi, Yoshiya; Boyarkin, Oleg V; Ebata, Takayuki; Rizzo, Thomas R

    2012-04-01

    We report UV photodissociation (UVPD) and IR-UV double-resonance spectra of 1,2-dimethoxybenzene (DMB) complexes with alkali metal ions, M(+)·DMB (M = Li, Na, K, Rb, and Cs), in a cold, 22-pole ion trap. The UVPD spectrum of the Li(+) complex shows a strong origin band. For the K(+)·DMB, Rb(+)·DMB, and Cs(+)·DMB complexes, the origin band is very weak and low-frequency progressions are much more extensive than that of the Li(+) ion. In the case of the Na(+)·DMB complex, spectral features are similar to those of the K(+), Rb(+), and Cs(+) complexes, but vibronic bands are not resolved. Geometry optimization with density functional theory indicates that the metal ions are bonded to the oxygen atoms in all the M(+)·DMB complexes. For the Li(+) complex in the S(0) state, the Li(+) ion is located in the same plane as the benzene ring, while the Na(+), K(+), Rb(+), and Cs(+) ions are located off the plane. In the S(1) state, the Li(+) complex has a structure similar to that in the S(0) state, providing the strong origin band in the UV spectrum. In contrast, the other complexes show a large structural change in the out-of-plane direction upon S(1)-S(0) excitation, which results in the extensive low-frequency progressions in the UVPD spectra. For the Na(+)·DMB complex, fast charge transfer occurs from Na(+) to DMB after the UV excitation, making the bandwidth of the UVPD spectrum much broader than that of the other complexes and producing the photofragment DMB(+) ion.

  4. Simultaneous near-IR spectroscopy and magnetic resonance imaging to assess cerebral oxygenation and brain water during hypoxia-ischemia in two-week-old rats

    Science.gov (United States)

    Shaw, R. A.; Tuor, U. I.; Foniok, T.; Bascaramurty, S.; Ringland, K.; McKenzie, E.; Qiao, M.; Tomanek, B.; Mantsch, Henry H.

    2001-10-01

    Cerebral near-infrared spectroscopy can potentially probe several parameters related to the onset of stroke and the ensuing tissue damage. One obvious marker of ischemia is cerebral oxygenation, which can be lowered sharply in stroke-affected tissue. Also commonly assessed, though less straightforward to recover, is the redox state of the cytochrome aa3 copper center. Finally, parameters that are in principle available but seldom recovered from in vivo near-IR spectra are changes in water concentration and scattering properties of the tissue. We have evaluated the potential for near-IR spectroscopy to detect relevant changes in cerebral oxygenation, blood volume, water content, and scattering properties in an infant rat stroke model that is well characterized by magnetic resonance imaging methods. The specific aim was to acquire near-IR spectra simultaneously with MR images and to correlate stroke-associated changes detected via these two modalities prior to, during and after a hypoxia-ischemia episode within this stroke model. Presented here are results from the design and testing of a near-IR illumination/detection system that is compatible with an MR imaging system, and the recovery of trends in the near-IR spectra that complement the hypoxic-ischemic changes observed in the MR images. Unexpectedly large intensity changes observed for the in vivo near-IR water absorptions are ascribed to hypoxia-induced variations in effective optical pathlength, suggesting that the water absorptions may prove generally useful as a means to track such changes.

  5. Evaluation of fourier transform infrared (FT-IR) spectroscopy and chemometrics as a rapid approach for subtyping E. coli O157:H7 isolates

    Science.gov (United States)

    The importance of tracking outbreaks of foodborne illness and the emergence of new virulent subtypes of foodborne pathogens have created the need for rapid and reliable subtyping methods for Escherichia coli O157:H7. Fourier transform infrared (FT-IR) spectroscopy coupled with multivariate statistic...

  6. Classification and structural analysis of live and dead salmonella cells using fourier transform infrared (FT-IR) spectroscopy and principle component analysis (PCA)

    Science.gov (United States)

    Fourier Transform Infrared Spectroscopy (FT-IR) was used to detect Salmonella typhimurium and Salmonella enteritidis foodborne bacteria and distinguish between live and dead cells of both serotypes. Bacteria were loaded individually on the ZnSe Attenuated Total Reflection (ATR) crystal surface and s...

  7. The studies of FT-IR and CD spectroscopy on catechol oxidase I from tobacco

    Science.gov (United States)

    Xiao, Hourong; Xie, Yongshu; Liu, Qingliang; Xu, Xiaolong; Shi, Chunhua

    2005-10-01

    A novel copper-containing enzyme named COI (catechol oxidase I) has been isolated and purified from tobacco by extracting acetone-emerged powder with phosphate buffer, centrifugation at low temperature, ammonium sulfate fractional precipitation, and column chromatography on DEAE-sephadex (A-50), sephadex (G-75), and DEAE-celluse (DE-52). PAGE, SDS-PAGE were used to detect the enzyme purity, and to determine its molecular weight. Then the secondary structures of COI at different pH, different temperatures and different concentrations of guanidine hydrochloride (GdnHCl) were studied by the FT-IR, Fourier self-deconvolution spectra, and circular dichroism (CD). At pH 2.0, the contents of both α-helix and anti-parallel β-sheet decrease, and that of random coil increases, while β-turn is unchanged compared with the neutral condition (pH 7.0). At pH 11.0, the results indicate that the contents of α-helix, anti-parallel β-sheet and β-turn decrease, while random coil structure increases. According to the CD measurements, the relative average fractions of α-helix, anti-parallel β-sheet, β-turn/parallel β-sheet, aromatic residues and disulfide bond, and random coil/γ-turn are 41.7%, 16.7%, 23.5%, 11.3%, and 6.8% at pH 7.0, respectively, while 7.2%, 7.7%, 15.2%, 10.7%, 59.2% at pH 2.0, and 20.6%, 9.5%, 15.2%, 10.5%, 44.2% at pH 11.0. Both α-helix and random coil decrease with temperature increasing, and anti-parallel β-sheet increases at the same time. After incubated in 6 mol/L guanidine hydrochloride for 30 min, the fraction of α-helix almost disappears (only 1.1% left), while random coil/γ-turn increases to 81.8%, which coincides well with the results obtained through enzymatic activity experiment.

  8. Far IR Transmission Characteristics of Silicon Nitride Films using Fourier Transform Spectroscopy

    Science.gov (United States)

    Ferrusca, D.; Castillo-Domínguez, E.; Velázquez, M.; Hughes, D.; Serrano, A.; Torres-Jácome, A.

    2009-12-01

    We are fabricating amorphous Silicon (a-Si) bolometers doped with boron with a measured NEP˜1.5×10-16 W/Hz1/2 suitable for use in millimeter and sub-millimeter astronomy. In this paper we present the preliminary results of the absorber optimization for the a-Si bolometers. A film of Silicon Nitride (SiN), deposited by LPCVD (Low Pressure Chemical Vapor Deposition) process at INAOE, with or without metallic coating is used as a weak thermal link to the heat sink as well as an absorber. We have measured the transmission spectrum of thin films of SiN in the range of 200 to 1000 GHz using Fourier Transform Spectroscopy (FTS) and a bolometric system with a NEP˜1.26×10-13. The transmission of thin films of SiN with a thickness of 0.4 μn has been measured at temperatures of 290 K and 4 K. The uncoated SiN films have a transmission of 80% and we expect a 50% transmission for the metallic (e.g. Titanium) coated films.

  9. IR-spectroscopy of CO adsorption on mixed-terminated ZnO surfaces

    Science.gov (United States)

    Buchholz, Maria; Yu, Xiaojuan; Yang, Chengwu; Heißler, Stefan; Nefedov, Alexei; Wang, Yuemin; Wöll, Christof

    2016-10-01

    The adsorption of CO on two different mixed-terminated, single-crystal surfaces of zinc oxide, ZnO(10 1 -0) and ZnO(11 2 -0), was investigated by employing infrared reflection absorption spectroscopy (IRRAS) using p- and s-polarized light. For both surfaces, one negative CO band was observed only for p-polarized light, indicating that CO is bound to the surface Zn2 + sites in a nearly upright geometry. In addition, we observed a substantial coverage-induced frequency shift for CO adsorption on both ZnO surfaces. For ZnO(10 1 -0), the ν(C-O) band shows a red shift of 16 cm- 1 when increasing the CO coverage from 0.5 ML (2185 cm- 1) to 1 ML (2169 cm- 1). On the ZnO(11 2 -0) surface, for isolated CO molecules, a frequency of 2192 cm- 1 was detected. The CO band shifts to 2170 cm- 1 at full monolayer. On both surfaces, the coverage-dependent frequency shift is attributed to a combination of dynamic and substrate-mediated static adsorbate-adsorbate interactions.

  10. Hubble Space Telescope Near-IR Transmission Spectroscopy of the Super-Earth HD 97658b

    CERN Document Server

    Knutson, Heather A; Kreidberg, Laura; Kempton, Eliza M -R; McCullough, P R; Fortney, Jonathan J; Bean, Jacob L; Gillon, Michael; Homeier, Derek; Howard, Andrew W

    2014-01-01

    Recent results from the Kepler mission indicate that super-Earths (planets with masses between 1-10 times that of the Earth) are the most common kind of planet around nearby Sun-like stars. These planets have no direct solar system analogue, and are currently one of the least well-understood classes of extrasolar planets. Many super-Earths have average densities that are consistent with a broad range of bulk compositions, including both water-dominated worlds and rocky planets covered by a thick hydrogen and helium atmosphere. Measurements of the transmission spectra of these planets offer the opportunity to resolve this degeneracy by directly constraining the scale heights and corresponding mean molecular weights of their atmospheres. We present Hubble Space Telescope near-infrared spectroscopy of two transits of the newly discovered transiting super-Earth HD 97658b. We use the Wide Field Camera 3's scanning mode to measure the wavelength-dependent transit depth in thirty individual bandpasses. Our averaged ...

  11. Application of FT-IR spectroscopy for control of the medium composition during the biodegradation of nitro aromatic compounds.

    Science.gov (United States)

    Grube, Mara; Muter, Olga; Strikauska, Silvija; Gavare, Marita; Limane, Baiba

    2008-11-01

    Previous studies showed that cabbage leaf extract (CLE) added to the growth medium can noticeably promote the degradation of nitro aromatic compounds by specific consortium of bacteria upon their growth. For further development of the approach for contaminated soil remediation it was necessary to evaluate the qualitative and/or quantitative composition of different origin CLE and their relevance on the growth of explosives-degrading bacteria. Six CLE (different by species, cultivars and harvesting time) were tested and used as additives to the growth medium. It was shown that nitro aromatic compounds can be identified in the FT-IR absorption spectra by the characteristic band at 1,527 cm(-1), and in CLE by the characteristic band at 1,602 cm(-1). The intensity of the CLE band at 1,602 cm(-1) correlated with the concentration of total nitrogen (R2=0.87) and decreased upon the growth of bacteria. The content of nitrogen in CLE differed (0.22-1.00 vol.%) and significantly influenced the content of total carbohydrates (9.50-16.00% DW) and lipids [3.90-9.90% dry weight (DW)] accumulated in bacterial cells while the content of proteins was similar in all samples. Though this study showed quantitative differences in the composition of the studied CLE and the response of bacterial cells to the composition of the growth media, and proved the potential of this additive for remediation of contaminated soil. It was shown that analysis of CLE and monitoring of the conversion of nitro aromatic compounds can be investigated by FT-IR spectroscopy as well as by conventional chemical methods.

  12. Hubble space telescope near-ir transmission spectroscopy of the super-Earth HD 97658B

    Energy Technology Data Exchange (ETDEWEB)

    Knutson, Heather A. [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Dragomir, Diana [Las Cumbres Observatory Global Telescope Network, Goleta, CA 93117 (United States); Kreidberg, Laura; Bean, Jacob L. [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States); Kempton, Eliza M.-R. [Department of Physics, Grinnell College, Grinnell, IA 50112 (United States); McCullough, P. R. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Fortney, Jonathan J. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Gillon, Michael [Institut d' Astrophysique et de Géophysique, Universiteé de Liége, Liége 1 (Belgium); Homeier, Derek [Centre de Recherche Astrophysique de Lyon, F-69364 Lyon (France); Howard, Andrew W., E-mail: hknutson@caltech.edu [Institute for Astronomy, University of Hawaii at Manoa, Honolulu, HI 96822 (United States)

    2014-10-20

    Recent results from the Kepler mission indicate that super-Earths (planets with masses between 1-10 times that of the Earth) are the most common kind of planet around nearby Sun-like stars. These planets have no direct solar system analogue, and are currently one of the least well-understood classes of extrasolar planets. Many super-Earths have average densities that are consistent with a broad range of bulk compositions, including both water-dominated worlds and rocky planets covered by a thick hydrogen and helium atmosphere. Measurements of the transmission spectra of these planets offer the opportunity to resolve this degeneracy by directly constraining the scale heights and corresponding mean molecular weights of their atmospheres. We present Hubble Space Telescope near-infrared spectroscopy of two transits of the newly discovered transiting super-Earth HD 97658b. We use the Wide Field Camera 3's (WFC3) scanning mode to measure the wavelength-dependent transit depth in 30 individual bandpasses. Our averaged differential transmission spectrum has a median 1σ uncertainty of 23 ppm in individual bins, making this the most precise observation of an exoplanetary transmission spectrum obtained with WFC3 to date. Our data are inconsistent with a cloud-free solar metallicity atmosphere at the 10σ level. They are consistent at the 0.4σ level with a flat line model, as well as effectively flat models corresponding to a metal-rich atmosphere or a solar metallicity atmosphere with a cloud or haze layer located at pressures of 10 mbar or higher.

  13. Hubble space telescope near-ir transmission spectroscopy of the super-Earth HD 97658B

    International Nuclear Information System (INIS)

    Recent results from the Kepler mission indicate that super-Earths (planets with masses between 1-10 times that of the Earth) are the most common kind of planet around nearby Sun-like stars. These planets have no direct solar system analogue, and are currently one of the least well-understood classes of extrasolar planets. Many super-Earths have average densities that are consistent with a broad range of bulk compositions, including both water-dominated worlds and rocky planets covered by a thick hydrogen and helium atmosphere. Measurements of the transmission spectra of these planets offer the opportunity to resolve this degeneracy by directly constraining the scale heights and corresponding mean molecular weights of their atmospheres. We present Hubble Space Telescope near-infrared spectroscopy of two transits of the newly discovered transiting super-Earth HD 97658b. We use the Wide Field Camera 3's (WFC3) scanning mode to measure the wavelength-dependent transit depth in 30 individual bandpasses. Our averaged differential transmission spectrum has a median 1σ uncertainty of 23 ppm in individual bins, making this the most precise observation of an exoplanetary transmission spectrum obtained with WFC3 to date. Our data are inconsistent with a cloud-free solar metallicity atmosphere at the 10σ level. They are consistent at the 0.4σ level with a flat line model, as well as effectively flat models corresponding to a metal-rich atmosphere or a solar metallicity atmosphere with a cloud or haze layer located at pressures of 10 mbar or higher.

  14. A spectroelectrochemical cell for ultrafast two-dimensional infrared spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    El Khoury, Youssef; Van Wilderen, Luuk J. G. W.; Vogt, Tim; Winter, Ernst; Bredenbeck, Jens, E-mail: bredenbeck@biophysik.uni-frankfurt.org, E-mail: bredenbeck@biophysik.uni-frankfurt.de [Institut für Biophysik, Johann Wolfgang Goethe-Universität, Max-von-Laue-Strasse 1, 60438 Frankfurt (Germany)

    2015-08-15

    A spectroelectrochemical cell has been designed to combine electrochemistry and ultrafast two-dimensional infrared (2D-IR) spectroscopy, which is a powerful tool to extract structure and dynamics information on the femtosecond to picosecond time scale. Our design is based on a gold mirror with the dual role of performing electrochemistry and reflecting IR light. To provide the high optical surface quality required for laser spectroscopy, the gold surface is made by electron beam evaporation on a glass substrate. Electrochemical cycling facilitates in situ collection of ultrafast dynamics of redox-active molecules by means of 2D-IR. The IR beams are operated in reflection mode so that they travel twice through the sample, i.e., the signal size is doubled. This methodology is optimal for small sample volumes and successfully tested with the ferricyanide/ferrocyanide redox system of which the corresponding electrochemically induced 2D-IR difference spectrum is reported.

  15. An investigation of the effect of silicone oil on polymer intraocular lenses by means of PALS, FT-IR and Raman spectroscopies.

    Science.gov (United States)

    Chamerski, Kordian; Lesniak, Magdalena; Sitarz, Maciej; Stopa, Marcin; Filipecki, Jacek

    2016-10-01

    The effect of the polydimethylsiloxane (PDMS) based silicone oil, that is widely used in vitreoretinal surgery, on internal structures of the polymer intraocular lenses was investigated. The effect of PDMS was studied on the polymethyl methacrylate (PMMA) rigid lenses and poly(2-hydroxyethyl methacrylate) (PHEMA) flexible lenses. The research was carried out by means of the positron lifetime spectroscopy (PALS) as well as the infrared spectroscopy (FT-IR) and the Raman spectroscopy (RS). The studies involving the use of PALS and FT-IR methods have revealed that the PHEMA based lenses absorbed, whereas the PMMA lenses did not absorb, silicone oil. The results obtained with the use of the RS method were inconclusive, probably due to the too low intensity of the characteristic PDMS bands. The evidence from this study was discussed in terms of physics and related to the clinical use of both silicone oil and intraocular lenses. PMID:27261889

  16. An investigation of the effect of silicone oil on polymer intraocular lenses by means of PALS, FT-IR and Raman spectroscopies

    Science.gov (United States)

    Chamerski, Kordian; Lesniak, Magdalena; Sitarz, Maciej; Stopa, Marcin; Filipecki, Jacek

    2016-10-01

    The effect of the polydimethylsiloxane (PDMS) based silicone oil, that is widely used in vitreoretinal surgery, on internal structures of the polymer intraocular lenses was investigated. The effect of PDMS was studied on the polymethyl methacrylate (PMMA) rigid lenses and poly(2-hydroxyethyl methacrylate) (PHEMA) flexible lenses. The research was carried out by means of the positron lifetime spectroscopy (PALS) as well as the infrared spectroscopy (FT-IR) and the Raman spectroscopy (RS). The studies involving the use of PALS and FT-IR methods have revealed that the PHEMA based lenses absorbed, whereas the PMMA lenses did not absorb, silicone oil. The results obtained with the use of the RS method were inconclusive, probably due to the too low intensity of the characteristic PDMS bands. The evidence from this study was discussed in terms of physics and related to the clinical use of both silicone oil and intraocular lenses.

  17. Hyperfine structure and lifetime measurements in the 4s2nd 2D3/2 Rydberg sequence of Ga I by time-resolved laser spectroscopy

    Science.gov (United States)

    Liu, Chunqing; Tian, Yanshan; Yu, Qi; Bai, Wanshuang; Wang, Xinghao; Wang, Chong; Dai, Zhenwen

    2016-05-01

    The hyperfine structure (HFS) constants of the 4s2nd 2D3/2 (n=6-18) Rydberg sequence and the 4s26p 2P3/2 level for two isotopes of 69Ga and 71Ga atoms were measured by means of the time-resolved laser-induced fluorescence (TR-LIF) technique and the quantum beat method. The observed hyperfine quantum beat spectra were analyzed and the magnetic-dipole HFS constants A as well as the electric-quadrupole HFS constants B of these levels were obtained by Fourier transform and a program for multiple regression analysis. Also using TR-LIF method radiative lifetimes of the above sequence states were determined at room temperature. The measured lifetime values range from 69 to 2279 ns with uncertainties no more than 10%. To our knowledge, the HFS constants of this Rydberg sequence and the lifetimes of the 4s2nd 2D3/2 (n=10-18) levels are reported for the first time. Good agreement between our results and the previous is achieved.

  18. Advance of Reaserch on Vegetable Oil and Fat Analysis Using IR Spectroscopy%红外光谱法植物油脂分析研究进展

    Institute of Scientific and Technical Information of China (English)

    王庆; 牛涛涛; 李娟; 杜秀转

    2012-01-01

    The basic principles and application of IR spectroscopy in the qualitative identification and the quantitative analysis of vegetable oil and fat were summerized.The advance of reaserch on the physical and chemical parameters of oil and fat using IR spectroscopy was discussed.The application prospect of the development on the detection of vegetable oil and fat by IR spectroscopy was put furward.An new idea was proposed that was the detection of oil and fat by several methods combination,which had great value of reference for applying generalized IR methods in oil and fat repid quantitative analysis and qualitative identification.%综述了红外光谱法在植物油脂油定性识别及定量分析中的应用。介绍了红外光谱法分析植物油脂的基本原理。论述了红外光谱法在油脂理化参数的定量分析的研究进展。展望了红外光谱法在油脂检测中的应用前景。提出多种方法联合运用的检测油脂的新思路,为红外光谱法油脂快速分析检以及定性识别分析提供参考。

  19. IR and Vibrational Circular Dichroism Spectroscopy of Matrine- and Artemisinin-Type Herbal Products: Stereochemical Characterization and Solvent Effects.

    Science.gov (United States)

    Zhang, Yuefei; Poopari, M Reza; Cai, Xiaoli; Savin, Aliaksandr; Dezhahang, Zahra; Cheramy, Joseph; Xu, Yunjie

    2016-04-22

    Five Chinese herbal medicines--matrine, oxymatrine, sophoridine, artemisinin, and dihydroartemisinin--were investigated using vibrational circular dichroism (VCD) experiments and density functional theory calculations to extract their stereochemical information. The three matrine-type alkaloids are available from the dry roots of Sophora flavescens and have long been used in various traditional Chinese herbal medicines to combat diseases such as cancer and cardiac arrhythmia. Artemisinin and the related dihydroartemisinin, discovered in 1979 by Professor Youyou Tu, a 2015 Nobel laureate in medicine, are effective drugs for the treatment of malaria. The VCD measurements were carried out in CDCl3 and DMSO-d6, two solvents with different dielectric constants and hydrogen-bonding characteristics. A "clusters-in-a-liquid" approach was used to model both explicit and implicit solvent effects. The studies show that effectively accounting for solvent effects is critical to using IR and VCD spectroscopy to provide unique spectroscopic features to differentiate the potential stereoisomers of these Chinese herbal medicines. PMID:27070079

  20. IR and Vibrational Circular Dichroism Spectroscopy of Matrine- and Artemisinin-Type Herbal Products: Stereochemical Characterization and Solvent Effects.

    Science.gov (United States)

    Zhang, Yuefei; Poopari, M Reza; Cai, Xiaoli; Savin, Aliaksandr; Dezhahang, Zahra; Cheramy, Joseph; Xu, Yunjie

    2016-04-22

    Five Chinese herbal medicines--matrine, oxymatrine, sophoridine, artemisinin, and dihydroartemisinin--were investigated using vibrational circular dichroism (VCD) experiments and density functional theory calculations to extract their stereochemical information. The three matrine-type alkaloids are available from the dry roots of Sophora flavescens and have long been used in various traditional Chinese herbal medicines to combat diseases such as cancer and cardiac arrhythmia. Artemisinin and the related dihydroartemisinin, discovered in 1979 by Professor Youyou Tu, a 2015 Nobel laureate in medicine, are effective drugs for the treatment of malaria. The VCD measurements were carried out in CDCl3 and DMSO-d6, two solvents with different dielectric constants and hydrogen-bonding characteristics. A "clusters-in-a-liquid" approach was used to model both explicit and implicit solvent effects. The studies show that effectively accounting for solvent effects is critical to using IR and VCD spectroscopy to provide unique spectroscopic features to differentiate the potential stereoisomers of these Chinese herbal medicines.

  1. A Study on the Surface Structures of Viscose-based Activated Carbon Fiber by FT-IR Spectroscopy and XPS

    Institute of Scientific and Technical Information of China (English)

    黄强; 黄永秋; 潘鼎

    2004-01-01

    Using viscose fiber (VF) as starting material and common steam as activating agent, formation of oxygen structures in activated carbon fiber is investigated. In the preparation of samples, VF was first heated at temperatures between 450℃ and 900℃ in N2 artmosphere. Then, in a successive activation stage, the product carbonized at 600℃ was activated in steam at 450 - 900℃ for 30 min, and at 600℃for 5- 30 min. The other carbonization products were activated at 600 and 900℃ for 30 min respectively. The products activated at 900℃ were then activated at 450℃ for 30 min again. The starting material, carbonized products and all activation products were examined by FT-IR spectroscopy and some products were examined by X-ray photoelectron spectroscope (XPS). And the yields of the carbonized and activated products were calculated. By analysing these spectra, the amount of oxygen-containing functional groups of the activated products attained under various activation time, various activation temperature and various previous carbonization temperature was determined.

  2. Evaluation of Salmon Adhesion on PET-Metal Interface by ATR, FT-IR, and Raman Spectroscopy

    Directory of Open Access Journals (Sweden)

    E. Zumelzu

    2015-01-01

    Full Text Available The material employed in this study is an ecoefficient, environmentally friendly, chromium (VI-free (noncarcinogenic metal polymer. The originality of the research lies in the study of the effect of new production procedures of salmon on metal packaging with multilayer polyethylene terephthalate (PET polymer coatings. Our hypothesis states that the adhesion of postmortem salmon muscles to the PET polymer coating produces surface and structural changes that affect the functionality and limit the useful life of metal containers, compromising therefore their recycling capacity as ecomaterials. This work is focused on studying the effects of the biochemical changes of postmortem salmon on the PET coating and how muscle degradation favors adhesion to the container. The experimental design considered a series of laboratory tests of containers simulating the conditions of canned salmon, chemical and physical tests of food-contact canning to evaluate the adhesion, and characterization of changes in the multilayer PET polymer by electron microscopy, ATR, FT-IR, and Raman spectroscopy analyses. The analyses determined the effect of heat treatment of containers on the loss of freshness of canned fish and the increased adhesion to the container wall, and the limited capability of the urea treatment to remove salmon muscle from the container for recycling purposes.

  3. FT-IR spectroscopy and multivariate analysis as an auxiliary tool for diagnosis of mental disorders: Bipolar and schizophrenia cases

    Science.gov (United States)

    Ogruc Ildiz, G.; Arslan, M.; Unsalan, O.; Araujo-Andrade, C.; Kurt, E.; Karatepe, H. T.; Yilmaz, A.; Yalcinkaya, O. B.; Herken, H.

    2016-01-01

    In this study, a methodology based on Fourier-transform infrared spectroscopy and principal component analysis and partial least square methods is proposed for the analysis of blood plasma samples in order to identify spectral changes correlated with some biomarkers associated with schizophrenia and bipolarity. Our main goal was to use the spectral information for the calibration of statistical models to discriminate and classify blood plasma samples belonging to bipolar and schizophrenic patients. IR spectra of 30 samples of blood plasma obtained from each, bipolar and schizophrenic patients and healthy control group were collected. The results obtained from principal component analysis (PCA) show a clear discrimination between the bipolar (BP), schizophrenic (SZ) and control group' (CG) blood samples that also give possibility to identify three main regions that show the major differences correlated with both mental disorders (biomarkers). Furthermore, a model for the classification of the blood samples was calibrated using partial least square discriminant analysis (PLS-DA), allowing the correct classification of BP, SZ and CG samples. The results obtained applying this methodology suggest that it can be used as a complimentary diagnostic tool for the detection and discrimination of these mental diseases.

  4. IGRINS Near-IR High-Resolution Spectroscopy of Multiple Jets around LkH$\\alpha$ 234

    CERN Document Server

    Oh, Heeyoung; Yuk, In-Soo; Park, Byeong-Gon; Park, Chan; Chun, Moo-Young; Pak, Soojong; Kim, Kang-Min; Oh, Jae Sok; Jeong, Ueejeong; Yu, Young Sam; Lee, Jae-Joon; Kim, Hwihyun; Hwang, Narae; Kaplan, Kyle; Pavel, Michael; Mace, Gregory; Lee, Hye-In; Le, Huynh Anh Nguyen; Lee, Sungho; Jaffe, Daniel T

    2016-01-01

    We present the results of high-resolution near-IR spectroscopy toward the multiple outflows around the Herbig Be star Lk{\\Ha} 234 using the Immersion Grating Infrared Spectrograph (IGRINS). Previous studies indicate that the region around Lk{\\Ha} 234 is complex, with several embedded YSOs and the outflows associated with them. In simultaneous H$-$ and K$-$band spectra from HH 167, we detected 5 {\\FeII} and 14 H$_{2}$ emission lines. We revealed a new {\\FeII} jet driven by radio continuum source VLA 3B. Position-velocity diagrams of H$_{2}$ 1$-$0 S(1) $\\lambda$2.122 $\\micron$ line show multiple velocity peaks. The kinematics may be explained by a geometrical bow shock model. We detected a component of H$_{2}$ emission at the systemic velocity (V$_{LSR}$ $=$ $-$10.2 {\\kms}) along the whole slit in all slit positions, which may arise from the ambient photodissociation region. Low-velocity gas dominates the molecular hydrogen emission from knots A and B in HH 167, which is close to the systemic velocity, {\\FeII} ...

  5. Investigation of multilayered polyelectrolyte thin films by means of refractive index measurements, FT-IR spectroscopy and SEM

    Science.gov (United States)

    Bodurov, I.; Vlaeva, I.; Exner, G.; Uzunova, Y.; Russev, S.; Pilicheva, B.; Viraneva, A.; Yovcheva, T.; Grancharova, Ts; Sotirov, S.; Marudova, M.

    2016-02-01

    Multilayered polyelectrolyte films are promising structures in the biomedical field. In order to meet the demands for biomedical applications, the structures have to be built from biocompatible and/or biodegradable, nontoxic starting materials, possessing some specific functional properties, depending on the particular application. In the present study, the multilayered polyelectrolyte films with potential use as buccal bioadhesive drug delivery systems were investigated. They were prepared via layer-by-layer deposition of successive nanolayers onto substrate. Three different biopolymers were used. The substrate, from poly(lactic acid), was solvent casted. After that, it was subjected to corona treatment, which ensures surface charge excess for the multilayer deposition. The nanolayers were prepared either from 0.01 g/L solutions of chitosan or 0.05 g/L xanthan. Acetate buffer (pH 4.5 and ionic strength 1 M) was used as a solvent. The substrate was dipped successively into one of the solutions, allowing formation of polyelectrolyte complexes of chitosan (polycation) and xanthan (polyanion). The substrates was treated in negative corona. The multilayered structures consisted of 8, 9, 14, 15 or 20 nanolayers. Number of techniques, such refractive index measurements, FT- IR spectroscopy and SEM morphology were employed in order to monitor the properties of the so prepared multilayered polyelectrolyte films.

  6. Quantification of water and silanol species on various silicas by coupling IR spectroscopy and in-situ thermogravimetry.

    Science.gov (United States)

    Gallas, Jean-Paul; Goupil, Jean-Michel; Vimont, Alexandre; Lavalley, Jean-Claude; Gil, Barbara; Gilson, Jean-Pierre; Miserque, Olivier

    2009-05-19

    Five silica samples (four precipitated silicas provided by commercial suppliers and one with the MCM-41 structure) have been studied by infrared spectroscopy and by a homemade thermogravimetry-infrared spectrum (TG-IR) setup. The silanol amount, accessibility to water, and different alcohols, and the affinity to water of these various silicas were compared and quantified. TG-IR measurements allowed the precise determination of the integrated molar absorption coefficient of the (nu+delta)OH band, epsilon(nu+delta)OH=(0.16+/-0.01) cm micromol(-1). It is independent of the sample origin and the concentration of silanol groups on silicas. For the precipitated dried samples evacuated at room temperature, the silanol concentration COH varies between 3.6 and 7.0 mmol g(-1). It is 5.3 mmol g(-1) in the case of the MCM-41 sample. Exchange experiments with D2O, followed by back-exchanges with different alcohols (methanol, propan-2-ol, 2-methyl-propan-2-ol, and 3-ethyl-pentan-3-ol) have been followed by infrared spectroscopy. All of the silanols of the MCM-41 sample are accessible to water and alcohol molecules. By contrast, about 20% of the silanols in precipitated samples are not exchanged by D2O (internal silanols). Accessibility decreases with alcohol size; the main effect is relative to methanol. Taking into account the sample specific surface areas and the silanol accessibility to D2O, the surface silanol density of precipitated silicas is close to 8 OH per nm2, at maximum coverage. At variance, the silanol surface density of the MCM silica is much lower, 4 OH per nm2. The TG-IR setup has also been used to determine the amount of water adsorbed on silicas through the intensity of the deltaH2O band. It varies linearly with the concentration of adsorbed water, whatever the silica sample. The integrated molar absorption coefficient of two bands, epsilondeltaH2O=(1.53+/-0.03) cm micromol(-1) and epsilon(nu+delta)H2O=(0.22+/-0.01) cm micromol(-1), have been determined. The

  7. Quantitative analysis of surface amine groups on plasma-polymerized ethylenediamine films using UV-visible spectroscopy compared to chemical derivatization with FT-IR spectroscopy, XPS and TOF-SIMS

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jinmo [Department of Physics, Brain Korea 21 Physics Research Division and Institute of Basic Science, Sungkyunkwan University (SKKU), Suwon 440-746 (Korea, Republic of); Division of Advanced Technology, Korea Research Institute of Standards and Science (KRISS), Daejeon 305-600 (Korea, Republic of); Jung, Donggeun [Department of Physics, Brain Korea 21 Physics Research Division and Institute of Basic Science, Sungkyunkwan University (SKKU), Suwon 440-746 (Korea, Republic of); Park, Yongsup [Division of Advanced Technology, Korea Research Institute of Standards and Science (KRISS), Daejeon 305-600 (Korea, Republic of); Kim, Yongki [Department of Physics, Brain Korea 21 Physics Research Division and Institute of Basic Science, Sungkyunkwan University (SKKU), Suwon 440-746 (Korea, Republic of); Division of Advanced Technology, Korea Research Institute of Standards and Science (KRISS), Daejeon 305-600 (Korea, Republic of); Moon, Dae Won [Division of Advanced Technology, Korea Research Institute of Standards and Science (KRISS), Daejeon 305-600 (Korea, Republic of); Lee, Tae Geol [Division of Advanced Technology, Korea Research Institute of Standards and Science (KRISS), Daejeon 305-600 (Korea, Republic of)]. E-mail: tglee@kriss.re.kr

    2007-02-28

    A quantitative analysis of the surface density of amine groups on a plasma-polymerized ethylenediamine thin film deposited on a platinum surface using inductively coupled plasma chemical vapor deposition method is described. UV-visible spectroscopy together with a chemical derivatization technique using Fourier transform infrared (FT-IR) spectroscopy was used to obtain the quantitative information. Chemical tags of pentafluorobenzaldehyde were hybridized with the surface amine groups and were easily detected due to the characteristic absorption bands of C-F stretching, aromatic ring and C=N stretching vibrations in the reflection-absorption FT-IR spectra. The surface amine density was reproducibly controlled as a function of deposition plasma power and quantified using UV-visible spectroscopy. A good linear correlation was observed between the FT-IR intensities of the characteristic absorption bands and the surface amine densities, suggesting the possibility of using this chemical derivatization technique to quantify the surface densities of specific functional groups on an organic surface. Chemical derivatization was also used with X-ray photoelectron spectroscopy on the same samples, and the results were compared with those obtained from FT-IR and time-of-flight secondary ion mass spectrometry. Although each analysis technique has different probing depths from the surface, the three different data sets obtained from the chemical tags correlated well with each other since each analysis technique measured the chemical tags on the sample surface.

  8. Study on Senna alata and its different extracts by Fourier transform infrared spectroscopy and two-dimensional correlation infrared spectroscopy

    Science.gov (United States)

    Adiana, M. A.; Mazura, M. P.

    2011-04-01

    Senna alata L. commonly known as candle bush belongs to the family of Fabaceae and the plant has been reported to possess anti-inflammatory, analgesic, laxative and antiplatelet-aggregating activity. In order to develop a rapid and effective analysis method for studying integrally the main constituents in the medicinal materials and their extracts, discriminating the extracts from different extraction process, comparing the categories of chemical constituents in the different extracts and monitoring the qualities of medicinal materials, we applied Fourier transform infrared spectroscopy (FT-IR) associated with second derivative infrared spectroscopy and two-dimensional infrared correlation spectroscopy (2D-IR) to study the main constituents of S. alata and its different extracts (extracted by hexane, dichloromethane, ethyl acetate and methanol in turn). The findings indicated that FT-IR and 2D-IR can provide many holistic variation rules of chemical constituents. Use of the macroscopical fingerprint characters of FT-IR and 2D-IR spectrum can identify the main chemical constituents in medicinal materials and their extracts, but also compare the components differences among similar samples. In a conclusion, FT-IR spectroscopy combined with 2D correlation analysis provides a powerful method for the quality control of traditional medicines.

  9. Real-time feedback control using online attenuated total reflection Fourier transform infrared (ATR FT-IR) spectroscopy for continuous flow optimization and process knowledge.

    Science.gov (United States)

    Skilton, Ryan A; Parrott, Andrew J; George, Michael W; Poliakoff, Martyn; Bourne, Richard A

    2013-10-01

    The use of automated continuous flow reactors is described, with real-time online Fourier transform infrared spectroscopy (FT-IR) analysis to enable rapid optimization of reaction yield using a self-optimizing feedback algorithm. This technique has been applied to the solvent-free methylation of 1-pentanol with dimethyl carbonate using a γ-alumina catalyst. Calibration of the FT-IR signal was performed using gas chromatography to enable quantification of yield over a wide variety of flow rates and temperatures. The use of FT-IR as a real-time analytical technique resulted in an order of magnitude reduction in the time and materials required compared to previous studies. This permitted a wide exploration of the parameter space to provide process understanding and validation of the optimization algorithms. PMID:24067568

  10. Adsorption and oxidation of formaldehyde on a polycrystalline Pt film electrode: An in situ IR spectroscopy search for adsorbed reaction intermediates.

    Science.gov (United States)

    Jusys, Zenonas; Behm, R Jürgen

    2014-01-01

    As part of a mechanistic study of the electrooxidation of C1 molecules we have systematically investigated the dissociative adsorption/oxidation of formaldehyde on a polycrystalline Pt film electrode under experimental conditions optimizing the chance for detecting weakly adsorbed reaction intermediates. Employing in situ IR spectroscopy in an attenuated total reflection configuration (ATR-FTIRS) with p-polarized IR radiation to further improve the signal-to-noise ratio, and using low reaction temperatures (3 °C) and deuterium substitution to slow down the reaction kinetics and to stabilize weakly adsorbed reaction intermediates, we could detect an IR absorption band at 1660 cm(-1) characteristic for adsorbed formyl intermediates. This assignment is supported by an isotope shift in wave number. Effects of temperature, potential and deuterium substitution on the formation and disappearance of different adsorbed species (COad, adsorbed formate, adsorbed formyl), are monitored and quantified. Consequences on the mechanism for dissociative adsorption and oxidation of formaldehyde are discussed.

  11. IR spectroscopy together with multivariate data analysis as a process analytical tool for in-line monitoring of crystallization process and solid-state analysis of crystalline product

    DEFF Research Database (Denmark)

    Pöllänen, Kati; Häkkinen, Antti; Reinikainen, Satu-Pia;

    2005-01-01

    Crystalline product should exist in optimal polymorphic form. Robust and reliable method for polymorph characterization is of great importance. In this work, infra red (IR) spectroscopy is applied for monitoring of crystallization process in situ. The results show that attenuated total reflection...... Fourier transform infra red (ATR-FTIR) spectroscopy provides valuable information on process, which can be utilized for more controlled crystallization processes. Diffuse reflectance Fourier transform infra red (DRIFT-IR) is applied for polymorphic characterization of crystalline product using X...... techniques provide the powerful tool for rapid evaluation of spectral data and also enable more reliable quantification of polymorphic composition of samples being mixtures of two or more polymorphs. This opens new perspectives for understanding crystallization processes and increases the level of safety...

  12. Light propagation in paint and prostate human tissues using visible to mid-IR spectroscopy and imaging techniques

    Science.gov (United States)

    Ali, Jamal Hafiez

    The topic of the thesis is to understand the structural and molecular changes in scattering media for bio-medical applications such as animal, and human prostate tissues and non-biomedical applications such as corrosion and cracks beneath paint using steady and time-resolved light spectroscopy and imaging techniques in the visible to mid-IR spectral region. The thesis focuses also on understanding the randomization of coherence and polarization in thin scattering paint medium. Temporal polarization emission profiles of Fluorescein dye attached to different molecular weight ranging from 4 K to 500 K were measured. Images of an object containing varying molecular weight of Fluorescein dye embedded inside intralipid media were investigated. The non-invasive spectral polarization difference imaging and the fluorescence polarization difference imaging techniques using Cardio Green dye are introduced in the optical imaging studies to enhance the image quality. The measured transport length for prostate tissues using time-resolved pulse transmission is ℓtr = 0.86 mm. Four modeling samples of human rectum-membrane-prostate tissue were investigated using the near-infrared spectral polarization imaging technique to detect small foreign objects at different depths inside prostate tissues. The content of water in cancerous and normal human prostate tissues was shown to be different using near infrared spectroscopy and imaging techniques. The OH stretching vibrational overtone mode at 980 nm, 1195 nm, 1444 nm and other water overtone modes provide key spectroscopic fingerprints to detect non-invasively cancer in prostate tissue. The value of the transport length (ℓtr) for paint medium obtained from time-resolved pulse transmission, steady state, and degree of polarization measurements is 28mum, 34mu m, and 29mum, respectively. The correlation of time-resolved interference (coherence) and polarization in a scattering thin paint medium has been determined for the first time

  13. Ir-Uv Double Resonance Spectroscopy of a Cold Protonated Fibril-Forming Peptide: NNQQNY\\cdotH+

    Science.gov (United States)

    DeBlase, Andrew F.; Harrilal, Christopher P.; Walsh, Patrick S.; McLuckey, Scott A.; Zwier, Timothy S.

    2016-06-01

    Protein aggregation to form amyloid-like fibrils is a purported molecular manifestation that leads to Alzheimer's, Huntington's, and other neurodegenerative diseases. The propensity for a protein to aggregate is often driven by the presence of glutamine (Q) and asparagine (N) rich tracts within the primary sequence. For example, Eisenberg and coworkers [Nature 2006, 435, 773] have shown by X-ray crystallography that the peptides NNQQNY and GNNQQNY aggregate into a parallel β-sheet configuration with side chains that intercalate into a "steric zipper". These sequences are commonly found at the N-terminus of the prion-determining domain in the yeast protein Sup35, a typical fibril-forming protein. Herein, we invoke recent advances in cold ion spectroscopy to explore the nascent conformational preferences of the protonated peptides that are generated by electrospray ionization. Towards this aim, we have used UV and IR spectroscopy to record conformation-specific photofragment action spectra of the NNQQNY monomer cryogenically cooled in an octopole ion trap. This short peptide contains 20 hydride stretch oscillators, leading to a rich infrared spectrum with at least 18 resolved transitions in the 2800-3800 cm-1 region. The infrared spectrum suggests the presence of both a free acid OH moiety and an H-bonded tyrosine OH group. We compare our results with resonant ion dip infrared spectra (RIDIRS) of the acyl/NH-benzyl capped neutral glutamine amino acid and its corresponding dipeptide: Ac-Q-NHBn and Ac-QQ-NHBn, respectively. These comparisons bring empirical insight to the NH stretching region of the spectrum, which contains contributions from free and singly H-bonded NH2 side-chain groups, and from peptide backbone amide NH groups. We further compare our spectrum to harmonic calculations at the M05-2X/6-31+G* level of theory, which were performed on low energy structures obtained from Monte Carlo conformational searches using the Amber* and OPLS force fields to assess

  14. Surface-enhanced IR absorption spectroscopy of the KcsA potassium channel upon application of an electric field.

    Science.gov (United States)

    Yamakata, Akira; Shimizu, Hirofumi; Oiki, Shigetoshi

    2015-09-01

    Surface-enhanced IR absorption spectroscopy (SEIRAS) is a powerful tool for studying the structure of molecules adsorbed on an electrode surface (ATR-SEIRA). Coupled with an electrochemical system, structural changes induced by changes in the electric field can be detected. All the membrane proteins are subjected to the effect of membrane electric field, but conformational changes at different membrane potentials and their functional relevance have not been studied extensively except for channel proteins. In this contribution, background information of potential-dependent functional and structural changes of a prototypical channel, the KcsA channel, is summarized, and SEIRAS applied to the KcsA channel under the application of the potential is shown. The potassium channels allow K(+) to permeate selectively through the structural part called the selectivity filter, in which dehydrated K(+) ions interact with backbone carbonyls. In the absence of K(+), the selectivity filter undergoes conformational changes to the non-conductive collapsed conformation. To apply the electric field, the KcsA channels were fixed on the gold surface in either upside or reverse orientation. The SEIRA spectrum in K(+) or Na(+) solution revealed both backbone structural changes and local changes in the OCO-carboxylate groups. Upon application of the negative electric field, the spectrum of OCO was enhanced only in the K(+) solution. These results indicate that the negative electric field accumulates local K(+) concentration, which turned the collapsed filter to the conductive conformation. ATR-SEIRA serves as an unprecedented experimental system for examining membrane proteins under an electric field.

  15. Discrimination of edible oils and fats by combination of multivariate pattern recognition and FT-IR spectroscopy: A comparative study between different modeling methods

    Science.gov (United States)

    Javidnia, Katayoun; Parish, Maryam; Karimi, Sadegh; Hemmateenejad, Bahram

    2013-03-01

    By using FT-IR spectroscopy, many researchers from different disciplines enrich the experimental complexity of their research for obtaining more precise information. Moreover chemometrics techniques have boosted the use of IR instruments. In the present study we aimed to emphasize on the power of FT-IR spectroscopy for discrimination between different oil samples (especially fat from vegetable oils). Also our data were used to compare the performance of different classification methods. FT-IR transmittance spectra of oil samples (Corn, Colona, Sunflower, Soya, Olive, and Butter) were measured in the wave-number interval of 450-4000 cm-1. Classification analysis was performed utilizing PLS-DA, interval PLS-DA, extended canonical variate analysis (ECVA) and interval ECVA methods. The effect of data preprocessing by extended multiplicative signal correction was investigated. Whilst all employed method could distinguish butter from vegetable oils, iECVA resulted in the best performances for calibration and external test set with 100% sensitivity and specificity.

  16. Solution structure of the 45-residue ATP-binding peptide of adenylate kinase as determined by 2-D NMR, FTIR, and CD spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Fry, D.C.; Byler, D.M.; Susi, H.; Brown, E.M.; Kuby, S.A.; Mildyan, A.S.

    1986-05-01

    In the X-ray structure of adenylate kinase residues 1-45 exist as 47% ..cap alpha..-helix, 29% ..beta..-structure (strands and turns) and 24% coil. The solution structure of a synthetic peptide corresponding to residues 1-45, which constitutes the MgATP binding site was studied by 3 independent spectroscopic methods. Globularity of the peptide was shown by its broad NMR resonances which narrow upon denaturation, and by its ability to bind MgATP with similar affinity and conformation as the intact enzyme does. COSY and NOESY NMR methods at 250 and 500 MHz reveal proximities among NH, C..cap alpha.., and C..beta.. protons indicative of >20% ..cap alpha..-helix, and >20% ..beta..-structure. Correlation of regions of secondary structure with the primary sequence by 2D NMR indicates at least one ..cap alpha..-helix (res. 23 to 29) and two ..beta..-strands (res. 12 to 15 and 34 to 38). The broad amide I band in the deconvoluted FTIR spectrum could be fit as the sum of 4 peaks due to specific secondary structures, yielding less than or equal to=45% ..cap alpha..-helix, less than or equal to=40% ..beta..-structure and greater than or equal to=15% coil. The CD spectrum, from 185-250 nm, interpreted with a 3-parameter basis set, yielded 20 +/- 5% ..cap alpha..=helix, and less than or equal to=20% ..beta..-structure. The solution structure of peptide 1-45 thus approximates that of residues 1-45 in the crystal.

  17. An X-ray photoelectron spectroscopy study of the products of the interaction of gaseous IrF6 with fine UO2F2

    Directory of Open Access Journals (Sweden)

    Prusakov Vladimir N.

    2007-01-01

    Full Text Available Nuclear fuel reprocessing by fluorination, a dry method of regeneration of spent nuclear fuel, uses UO2F2 for the separation of plutonium from gaseous mixtures. Since plutonium requires special treatment, IrF6 was used as a thermodynamic model of PuF6. The model reaction of the interaction of gaseous IrF6 with fine UO2F2 in the sorption column revealed a change of color of the sorption column contents from pale-yellow to gray and black, indicating the formation of products of such an interaction. The X-ray photoelectron spectroscopy study showed that the interaction of gaseous IrF6 with fine UO2F2 at 125 °C results in the formation of stable iridium compounds where the iridium oxidation state is close to Ir3+. The dependence of the elemental compositions of the layers in the sorption column on the penetration depth of IrF6 was established.

  18. Friction behaviour of TiAlN films around cubic/hexagonal transition: A 2D grazing incidence X-ray diffraction and electron energy loss spectroscopy study

    Energy Technology Data Exchange (ETDEWEB)

    Pinot, Y. [Université de Haute Alsace, Laboratoire Physique et Mécanique Textiles (EA 4365), F-68093 Mulhouse (France); Pac, M.-J., E-mail: marie-jose.pac@uha.fr [Université de Haute Alsace, Laboratoire Physique et Mécanique Textiles (EA 4365), F-68093 Mulhouse (France); Henry, P. [Université de Haute Alsace, Laboratoire Physique et Mécanique Textiles (EA 4365), F-68093 Mulhouse (France); Rousselot, C. [Université de Franche-Comté, FEMTO-ST (UMR CNRS 6174), F-25211 Montbéliard (France); Odarchenko, Ya.I.; Ivanov, D.A. [Université de Haute Alsace, Institut de Science des Matériaux de Mulhouse (UMR 7361 CNRS), F-68093 Mulhouse (France); Ulhaq-Bouillet, C.; Ersen, O. [Université de Strasbourg, Institut de Physique et Chimie des Matériaux de Strasbourg (UMR CNRS 7504), F-67087 Strasbourg (France); Tuilier, M.-H. [Université de Haute Alsace, Laboratoire Physique et Mécanique Textiles (EA 4365), F-68093 Mulhouse (France)

    2015-02-27

    The properties at different scales of Ti{sub 1−x}Al{sub x}N films deposited by reactive magnetron sputtering from TiAl sintered (S) targets produced by powder metallurgy are compared with those of a set of films previously deposited in the same conditions from mosaic targets (M) made of pure Ti and Al metals. For compositions close to the hcp/fcc transition (around x = 0.6), the friction behaviour, growth directions and organization of crystallized domains are found to be sensitive to the type of target used. The resistance to crack creation is higher for Ti{sub 0.54}Al{sub 0.46}N (S) and Ti{sub 0.38}Al{sub 0.62}N (S) than for Ti{sub 0.50}Al{sub 0.50}N (M) and Ti{sub 0.32}Al{sub 0.68}N (M). From the measurement of mechanical properties, toughness, and wear volumes and from the observation of wear tracks, it is found that films prepared from sintered targets exhibit a better wear resistance. Grazing incidence X-ray diffraction and electron energy loss spectroscopy in Transmission Electronic Microscopy are used to investigate the long- and short-range orders within the films. The morphology of Ti{sub 0.54}Al{sub 0.46}N (S) film can be considered as an array of crystalline domains having reciprocal-space vectors 111 and 200 directed along the meridian but with random in-plane orientation. Ti{sub 0.38}Al{sub 0.62}N (S) Al-rich film presents a random orientation of the crystalline domains whereas Ti{sub 0.32}Al{sub 0.68}N (M) deposited from composite targets exhibits a well-oriented fibrillar structure. The N K-edge Electron Energy Loss Near Edge Spectra are discussed with previous results of Extended X-ray Absorption Fine Structure Spectroscopy, which has evidenced different values of Al–N and Ti–N bond lengths, either octahedral (cubic-like) or tetrahedral (hexagonal-like) within Ti{sub 0.50}Al{sub 0.50}N (M) and Ti{sub 0.32}Al{sub 0.68}N (M) films. For similar compositions, films deposited from sintered alloys contain more nitrogen atoms in octahedral cubic

  19. Cerebral gliomas: prospective comparison of multivoxel 2D chemical-shift imaging proton MR spectroscopy, echoplanar perfusion and diffusion-weighted MRI

    International Nuclear Information System (INIS)

    Developments in MRI have made it possible to use diffusion-weighted MRI, perfusion MRI and proton MR spectroscopy (MRS) to study lesions in the brain. We evaluated whether these techniques provide useful, complementary information for grading gliomas, in comparison with conventional MRI. We studied 17 patients with histologically verified gliomas, adding multivoxel proton MRS, echoplanar diffusion and perfusion MRI the a routine MRI examination. The maximum relative cerebral blood volume (CBV), minimum apparent diffusion coefficient (ADC) and metabolic peak area ratios in proton MRS were calculated in solid parts of tumours on the same slice from each imaging data set. The mean minimum ADC of the 13 high-grade gliomas (0.92±0.27 x 10-3 mm2/s) was lower than that of the four low-grade gliomas (1.28±0.15 x 10-3 mm2/s) (P<0.05). Means of maximum choline (Cho)/N-acetylaspartate (NAA), Cho/creatine (Cr), Cho/Cr in normal brain (Cr-n) and minimum NAA/Cr ratios were 5.90±2.62, 4.73±2.22, 2.66±0.68 and 0.40±0.06, respectively, in the high-grade gliomas, and 1.65±1.37, 1.84±1.20, 1.61±1.29 and 1.65±1.61, respectively, in the low-grade gliomas. Significant differences were found on spectroscopy between the high- and low-grade gliomas (P<0.05). Mean maximum relative CBV in the high-grade gliomas (6.10±3.98) was higher than in the low-grade gliomas (1.74±0.57) (P<0.05). Echoplanar diffusion, perfusion MRI and multivoxel proton MRS can offer diagnostic information, not available with conventional MRI, in the assessment of glioma grade. (orig.)

  20. Ultra-broadband 2D electronic spectroscopy of carotenoid-bacteriochlorophyll interactions in the LH1 complex of a purple bacterium.

    Science.gov (United States)

    Maiuri, Margherita; Réhault, Julien; Carey, Anne-Marie; Hacking, Kirsty; Garavelli, Marco; Lüer, Larry; Polli, Dario; Cogdell, Richard J; Cerullo, Giulio

    2015-06-01

    We investigate the excitation energy transfer (EET) pathways in the photosynthetic light harvesting 1 (LH1) complex of purple bacterium Rhodospirillum rubrum with ultra-broadband two-dimensional electronic spectroscopy (2DES). We employ a 2DES apparatus in the partially collinear geometry, using a passive birefringent interferometer to generate the phase-locked pump pulse pair. This scheme easily lends itself to two-color operation, by coupling a sub-10 fs visible pulse with a sub-15-fs near-infrared pulse. This unique pulse combination allows us to simultaneously track with extremely high temporal resolution both the dynamics of the photoexcited carotenoid spirilloxanthin (Spx) in the visible range and the EET between the Spx and the B890 bacterio-chlorophyll (BChl), whose Qx and Qy transitions peak at 585 and 881 nm, respectively, in the near-infrared. Global analysis of the one-color and two-color 2DES maps unravels different relaxation mechanisms in the LH1 complex: (i) the initial events of the internal conversion process within the Spx, (ii) the parallel EET from the first bright state S2 of the Spx towards the Qx state of the B890, and (iii) the internal conversion from Qx to Qy within the B890.

  1. Ultra-broadband 2D electronic spectroscopy of carotenoid-bacteriochlorophyll interactions in the LH1 complex of a purple bacterium

    Energy Technology Data Exchange (ETDEWEB)

    Maiuri, Margherita [CNR-IFN, Dipartimento di Fisica, Politecnico di Milano, P.zza L. da Vinci 32, Milano 20133 (Italy); Department of Chemistry, Princeton University, Washington Road, Princeton, New Jersey 08544 (United States); Réhault, Julien; Polli, Dario; Cerullo, Giulio, E-mail: giulio.cerullo@polimi.it [CNR-IFN, Dipartimento di Fisica, Politecnico di Milano, P.zza L. da Vinci 32, Milano 20133 (Italy); Carey, Anne-Marie; Hacking, Kirsty; Cogdell, Richard J. [Glasgow Biomedical Research Centre, IBLS, University of Glasgow, 126 Place, Glasgow G12 8TA, Scotland (United Kingdom); Garavelli, Marco [Dipartimento di Chimica “G. Ciamician,” Università di Bologna, Via Selmi 2, IT-40126 Bologna (Italy); CNRS, Institut de Chimie de Lyon, École Normale Supérieure de Lyon, Université de Lyon, 46 Allée d’Italie, F-69364 Lyon Cedex 07 (France); Lüer, Larry [Madrid Institute for Advanced Studies, IMDEA Nanociencia, Madrid (Spain)

    2015-06-07

    We investigate the excitation energy transfer (EET) pathways in the photosynthetic light harvesting 1 (LH1) complex of purple bacterium Rhodospirillum rubrum with ultra-broadband two-dimensional electronic spectroscopy (2DES). We employ a 2DES apparatus in the partially collinear geometry, using a passive birefringent interferometer to generate the phase-locked pump pulse pair. This scheme easily lends itself to two-color operation, by coupling a sub-10 fs visible pulse with a sub-15-fs near-infrared pulse. This unique pulse combination allows us to simultaneously track with extremely high temporal resolution both the dynamics of the photoexcited carotenoid spirilloxanthin (Spx) in the visible range and the EET between the Spx and the B890 bacterio-chlorophyll (BChl), whose Q{sub x} and Q{sub y} transitions peak at 585 and 881 nm, respectively, in the near-infrared. Global analysis of the one-color and two-color 2DES maps unravels different relaxation mechanisms in the LH1 complex: (i) the initial events of the internal conversion process within the Spx, (ii) the parallel EET from the first bright state S{sub 2} of the Spx towards the Q{sub x} state of the B890, and (iii) the internal conversion from Q{sub x} to Q{sub y} within the B890.

  2. Solution structure of the 45-residue MgATP-binding peptide of adenylate kinase as examined by 2-D NMR, FTIR, and CD spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Fry, D.C.; Byler, D.M.; Susi, H.; Brown, M.; Kuby, S.A.; Mildvan A.S.

    1988-05-17

    The structure of a synthetic peptide corresponding to residues 1-45 of rabbit muscle adenylate kinase has been studied in aqueous solution by two-dimensional NMR, FTIR, and CD spectroscopy. This peptide, which binds MgATP and is believed to represent most of the MgATP-binding site of the enzyme, appears to maintain a conformation similar to that of residues 1-45 in the X-ray structure of intact porcine adenylate kinase, with 42% of the residues of the peptide showing NOEs indicative of phi and psi angles corresponding to those found in the protein. The NMR studies suggest that the peptide is composed of two helical regions of residues 4-7 and 23-29, and three stretches of ..beta..-strand at residues 8-15, 30-32, and 35-40, yielding an overall secondary structure consisting of 24% ..cap alpha..-helix, 38% ..beta..-structure, and 38% aperiodic. Although the resolution-enhanced amide I band of the peptide FTIR spectrum is broad and rather featureless, possible due to disorder, it can be fit by using methods developed on well-characterized globular proteins. The CD spectrum is best fit by assuming the presence of at most 13% ..cap alpha..-helix in the peptide, 24 +/- 2% ..beta..-structure, and 66 +/- 4% aperiodic. The inability of the high-frequency FTIR and CD methods to detect helices in the amount found by NMR may result from the short helical lengths as well as from static and dynamic disorder in the peptide. Upon binding of MgATP, numerous conformation changes in the backbone of the peptide are detected by NMR, with smaller alterations in the overall secondary structure as assess by CD.

  3. Application of Fourier transform infrared (FT-IR) spectroscopy to the study of the modification of epoxidized sunflower oil by acrylation.

    Science.gov (United States)

    Irinislimane, Ratiba; Belhaneche-Bensemra, Naima

    2012-12-01

    Commercial sunflower oil was epoxidized at the laboratory-scale. The epoxidized sunflower oil (ESFO) was modified following the acrylation reaction. Modification was carried out simultaneously using acrylic acid (AA) and triethylamine (TEA). To optimize the reaction conditions, the effects of four temperatures (40, 60, 80, and 100 °C), the ESFO:AA (100:100) ratio, and 0.2% TEA were investigated. The rate of conversion was analyzed with both FT-IR and titration of the oxirane ring. After that, the temperature with the highest conversion was selected and used throughout for all modification reactions. Then, four ratios (100:100, 100:90, 100:80, and 100:75) of ESFO:AA were analyzed at four different concentrations of TEA (0.2, 0.3, 0.4, and 0.5%) to determine the best estimate for both the ESFO:AA ratio and the catalyst concentration. Conversion rate was analyzed using FT-IR spectroscopy by measuring the concentrations of ester, carbonyl, and alcohol groups. Moreover, oxirane-ring concentration was estimated using the titration method (with gentian violet as indicator) and FT-IR spectroscopy (epoxy ring absorptions at 1270 cm(-1) and 877 cm(-1)). Based on conversion yield, the optimum ESFO:AA ratio corresponds to 100:80; the best temperature reaction was at 60 °C, and the best TEA concentration was 0.2%. The critical amounts of reactants needed to reach maximum conversion were established. The final acid value of the acrylated ESFO after washing (pH = 7) was 2.1 mg potassium hydroxide (KOH)·g(-1). All results show that FT-IR spectroscopy is a simple, low-cost, rapid method for investigating the kinetics of a reaction. PMID:23231904

  4. Synthesis, structural characterization, IR- and Raman spectroscopy, magnetic properties of new organically templated metal sulfates with 4-aminopyridinium

    Science.gov (United States)

    Bednarchuk, Tamara J.; Kinzhybalo, Vasyl; Bednarchuk, Oleksandr; Pietraszko, Adam

    2016-09-01

    Crystal structures of the series of twelve 4-aminopyridinium templated metal sulfates: (C5H7N2)2[MeII(H2O)6](SO4)2 (MeII = Cu (1), Co (2), Mg (3), Zn (4), Fe (5), Mn (6a)), (C5H7N2)2[MeII(H2O)4(SO4)2]·4H2O (MeII = Mn (6b), Cd (7a)), (C5H7N2)2[MnII(H2O)4(SO4)2] (6c), (C5H7N2)2[Cd(H2O)4(SO4)2] (7b), (C5H7N2)[Al(H2O)6](SO4)2·4H2O (low (8lt) and room temperature (8rt) phases) and (C5H7N2)[FeIII(H2O)4(SO4)2] (9) were determined by single-crystal X-ray diffraction. Compounds 1-6a are isostructural, crystal structure consists of [Me(H2O)6]2+ octahedra, 4-aminopyridinium cations (4ap) and sulfate anions. Crystal packing in 1-6a series is characterized by alternating 4ap and inorganic layers. In the structure of 1 Cu2+ coordination environment is axially deformed due to Jahn-Teller effect to tetragonal bipyramidal. Compounds 6 (a, b) and 7a at ambient conditions dehydrate to produce isostructural complexes 6c and 7b, respectively. In structures of 6c, 7b and 9 sulfate anions are involved in slightly distorted octahedral metal coordination composed of six O atoms from four water molecules and two sulfate anions. Room temperature phase of 8 is characterized by disorder of 4ap around center of inversion. Continuous phase transition at ≈185 K leads to the cell doubling and ordering of 4ap. All of the structures are governed by an extensive three-dimensional hydrogen bond networks, as well as π-π interactions visualized by Hirshfeld surface analysis. Moreover, selected compounds were characterized by the IR and Raman spectroscopy and magnetic measurement studies.

  5. Faecal near-IR spectroscopy to determine the nutritional value of diets consumed by beef cattle in east Mediterranean rangelands.

    Science.gov (United States)

    Landau, S Y; Dvash, L; Roudman, M; Muklada, H; Barkai, D; Yehuda, Y; Ungar, E D

    2016-02-01

    Rapid assessment of the nutritional quality of diets ingested by grazing animals is pivotal for successful cow-calf management in east Mediterranean rangelands, which receive unpredictable rainfall and are subject to hot-spells. Clipped vegetation samples are seldom representative of diets consumed, as cows locate and graze selectively. In contrast, faeces are easily sampled and their near-IR spectra contain information about nutrients and their utilization. However, a pre-requisite for successful faecal near-infrared reflectance spectroscopy (FNIRS) is that the calibration database encompass the spectral variability of samples to be analyzed. Using confined beef cows in Northern and Southern Israel, we calibrated prediction equations based on individual pairs of known dietary attributes and the NIR spectra of associated faeces (n=125). Diets were composed of fresh-cut green fodder of monocots (wheat and barley), dicots (safflower and garden pea) and natural pasture collected at various phenological states over 2 consecutive years, and, optionally, supplements of barley grain and dried poultry litter. A total of 48 additional pairs of faeces and diets sourced from cows fed six complete mixed rations covering a wide range of energy and CP concentrations. Precision (linearity of calibration, R2cal, and of cross-validation, R2cv) and accuracy (standard error of cross-validation, SEcv) were criteria for calibration quality. The calibrations for dietary ash, CP, NDF and in vitro dry matter digestibility yielded R2cal values >0.87, R2cv of 0.81 to 0.89 and SEcv values of 16, 13, 39 and 31 g/kg dry matter, respectively. Equations for nutrient intake were of low quality, with the exception of CP. Evaluation of FNIRS predictions was carried out with grazing animals supplemented or not with poultry litter, and implementation of the method in one herd over 2 years is presented. The potential usefulness of equations was also established by calculating the Mahalanobis (H

  6. Solution structure of the 45-residue MgATP-binding peptide of adenylate kinase as examined by 2-D NMR, FTIR, and CD spectroscopy.

    Science.gov (United States)

    Fry, D C; Byler, D M; Susi, H; Brown, E M; Kuby, S A; Mildvan, A S

    1988-05-17

    The structure of a synthetic peptide corresponding to residues 1-45 of rabbit muscle adenylate kinase has been studied in aqueous solution by two-dimensional NMR, FTIR, and CD spectroscopy. This peptide, which binds MgATP and is believed to represent most of the MgATP-binding site of the enzyme [Fry, D.C., Kuby, S.A., & Mildvan, A.S. (1985) Biochemistry 24, 4680-4694], appears to maintain a conformation similar to that of residues 1-45 in the X-ray structure of intact porcine adenylate kinase [Sachsenheimer, W., & Schulz, G.E. (1977) J. Mol. Biol. 114, 23-26], with 42% of the residues of the peptide showing NOEs indicative of phi and psi angles corresponding to those found in the protein. The NMR studies suggest that the peptide is composed of two helical regions of residues 4-7 and 23-29, and three stretches of beta-strand at residues 8-15, 30-32, and 35-40, yielding an overall secondary structure consisting of 24% alpha-helix, 38% beta-structure, and 38% aperiodic. Although the resolution-enhanced amide I band of the peptide FTIR spectrum is broad and rather featureless, possibly due to disorder, it can be fit by using methods developed on well-characterized globular proteins. On this basis, the peptide consists of 35 +/- 10% beta-structure, 60 +/- 12% turns and aperiodic structure, and not more than 10% alpha-helix. The CD spectrum is best fit by assuming the presence of at most 13% alpha-helix in the peptide, 24 +/- 2% beta-structure, and 66 +/- 4% aperiodic. The inability of the high-frequency FTIR and CD methods to detect helices in the amount found by NMR may result from the short helical lengths as well as from static and dynamic disorder in the peptide. Upon binding of MgATP, numerous conformational changes in the backbone of the peptide are detected by NMR, with smaller alterations in the overall secondary structure as assessed by CD. Detailed assignments of resonances in the peptide spectrum and intermolecular NOEs between protons of bound MgATP and

  7. Direct spectroscopy of the $^2$S$_{1/2}-^2$P$_{1/2}$ and $^2$D$_{3/2}-^2$P$_{1/2}$ transitions and observation of micromotion modulated spectra in trapped \\Ca

    CERN Document Server

    Pruttivarasin, Thaned; Haeffner, Hartmut

    2013-01-01

    We present an experimental scheme to perform spectroscopy of the $^2$S$_{1/2}-^2$P$_{1/2}$ and $^2$D$_{3/2}-^2$P$_{1/2}$ transitions in \\Ca. By rapidly switching lasers between both transitions, we circumvent the complications of both dark resonances and Doppler heating. We apply this method to directly observe the micromotion modulated fluorescence spectra of both transitions and measure the dependence of the micromotion modulation index on the trap frequency. With a measurement time of 10 minutes, we can detect the center frequencies of both dipole transitions with a precision on the order of 200 kHz even in the presence of strong micromotion.

  8. A Q-switched Ho:YAG laser assisted nanosecond time-resolved T-jump transient mid-IR absorbance spectroscopy with high sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Li, Deyong; Li, Yunliang; Li, Hao; Weng, Yuxiang, E-mail: yxweng@iphy.ac.cn [Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Wu, Xianyou [Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031 (China); Yu, Qingxu [School of Physics and Optoelectronic Technology, Dalian University of Technology, No. 2, Linggong Road, Dalian 116023 (China)

    2015-05-15

    Knowledge of dynamical structure of protein is an important clue to understand its biological function in vivo. Temperature-jump (T-jump) time-resolved transient mid-IR absorbance spectroscopy is a powerful tool in elucidating the protein dynamical structures and the folding/unfolding kinetics of proteins in solution. A home-built setup of T-jump time-resolved transient mid-IR absorbance spectroscopy with high sensitivity is developed, which is composed of a Q-switched Cr, Tm, Ho:YAG laser with an output wavelength at 2.09 μm as the T-jump heating source, and a continuous working CO laser tunable from 1580 to 1980 cm{sup −1} as the IR probe. The results demonstrate that this system has a sensitivity of 1 × 10{sup −4} ΔOD for a single wavelength detection, and 2 × 10{sup −4} ΔOD for spectral detection in amide I′ region, as well as a temporal resolution of 20 ns. Moreover, the data quality coming from the CO laser is comparable to the one using the commercial quantum cascade laser.

  9. A Q-switched Ho:YAG laser assisted nanosecond time-resolved T-jump transient mid-IR absorbance spectroscopy with high sensitivity.

    Science.gov (United States)

    Li, Deyong; Li, Yunliang; Li, Hao; Wu, Xianyou; Yu, Qingxu; Weng, Yuxiang

    2015-05-01

    Knowledge of dynamical structure of protein is an important clue to understand its biological function in vivo. Temperature-jump (T-jump) time-resolved transient mid-IR absorbance spectroscopy is a powerful tool in elucidating the protein dynamical structures and the folding/unfolding kinetics of proteins in solution. A home-built setup of T-jump time-resolved transient mid-IR absorbance spectroscopy with high sensitivity is developed, which is composed of a Q-switched Cr, Tm, Ho:YAG laser with an output wavelength at 2.09 μm as the T-jump heating source, and a continuous working CO laser tunable from 1580 to 1980 cm(-1) as the IR probe. The results demonstrate that this system has a sensitivity of 1 × 10(-4) ΔOD for a single wavelength detection, and 2 × 10(-4) ΔOD for spectral detection in amide I' region, as well as a temporal resolution of 20 ns. Moreover, the data quality coming from the CO laser is comparable to the one using the commercial quantum cascade laser.

  10. The Use and Evaluation of Scaffolding, Student Centered-Learning, Behaviorism, and Constructivism to Teach Nuclear Magnetic Resonance and IR Spectroscopy in a Two-Semester Organic Chemistry Course

    Science.gov (United States)

    Livengood, Kimberly; Lewallen, Denver W.; Leatherman, Jennifer; Maxwell, Janet L.

    2012-01-01

    Since 2002, infrared spectroscopy (IR) and nuclear magnetic resonance (NMR) spectrometry have been introduced at the beginning of the first-semester organic chemistry lab course at this university. Starting in 2008, each individual student was given 20 unique homework problems that consisted of multiple-choice [superscript 1]H NMR and IR problems…

  11. Cross-strand coupling of a beta-hairpin peptide stabilized with an Aib-Gly turn studied using isotope-edited IR spectroscopy.

    Science.gov (United States)

    Huang, Rong; Setnicka, Vladimir; Etienne, Marcus A; Kim, Joohyun; Kubelka, Jan; Hammer, Robert P; Keiderling, Timothy A

    2007-11-01

    Isotope-edited IR spectroscopy was used to study a series of singly and doubly 13C=O-labeled beta-hairpin peptides stabilized by an Aib-Gly turn sequence. The double-labeled peptides have amide I' IR spectra that show different degrees of vibrational coupling between the 13C-labeled amides due to variations in the local geometry of the peptide structure. The single-labeled peptides provide controls to determine frequencies characteristic of the diagonal force field (FF) contributions at each position for the uncoupled 13C=O modes. Separation of diagonal FF and coupling effects on the spectra are used to explain the cross-strand labeled spectral patterns. DFT calculations based on an idealized model beta-hairpin peptide correctly predict the vibrational coupling patterns. Extending these model results by consideration of frayed ends and the hairpin conformational flexibility yields an alternate interpretation of details of the spectra. Temperature-dependent isotopically labeled IR spectra reveal differences in the thermal stabilities of the individual isotopically labeled sites. This is the first example of using an IR-based isotopic labeling technique to differentiate structural transitions at specific sites along the peptide backbone in model beta-hairpin peptides.

  12. Spectroscopy and electronic structure of Sr2YRuO6 and Sr2YRu0.75Ir0.25O6

    Science.gov (United States)

    Guedes, E. B.; Abbate, M.; Abud, F.; Jardim, R. F.; Vicentin, F. C.; Mossanek, R. J. O.

    2016-07-01

    We study the electronic structure of the Sr2YRuO6 and Sr2YRu0.75Ir0.25O6 compounds using x-ray (resonant) photoemission and absorption spectroscopies. The experimental results are interpreted with first-principles calculations, which give a good agreement with all the spectra. These results show that, although the spin-orbit coupling does not induce orbital anisotropies in these systems, it is responsible for the reduction of magnetic moments within the the Ir5 +O6 octahedra, weakening the magnetic ordering in the substituted system. Finally, our findings support the idea that the canting of Ru5 + magnetic moments actually plays an important role in the stabilization of the intriguing magnetic ordering in the Sr2YRuO6 compound.

  13. Detection of Soluble and Fixed NH4+ in Clay Minerals by DTA and IR Reflectance Spectroscopy : A Potential Tool for Planetary Surface Exploration

    Science.gov (United States)

    Janice, Bishop; Banin, A.; Mancinelli, R. L.; Klovstad, M. R.; DeVincenzi, Donald L. (Technical Monitor)

    2001-01-01

    Nitrogen is an essential element for life. It is the only element among the six major biogenic elements, C, O, S, O, P, H, whose presence in the Martian soil has not been positively and directly established. We describe here a study assessing the ability to detect NH4 in soils by two methods: differential thermal analysis (DTA) and infrared (IR) reflectance spectroscopy. Four standard clay minerals (kaolinite, montmorillonite, illite and attapulgite) and an altered tephra sample from Mauna Kea were treated with NH4 in this study. Samples of the NH4-treated and leached clays were analyzed by DTA and infrared (IR) reflectance spectroscopy to quantify the delectability of soluble and sorbed/fixed NH4. An exotherm at 270-280 C was clearly detected in the DTA curves of NH4-treated (non-leached) samples. This feature is assigned to the thermal decomposition reaction of NH4. Spectral bands observed at 1.56, 2.05, 2.12, 3.06, 3.3, 3.5, 5.7 and 7.0 microns in the reflectance spectra of NH4-treated and leached samples are assigned to the sorbed/fixed ammonium in the clays. The montmorillonite has shown the most intense absorbance due to fixed ammonium among the leached samples in this study, as a result of its high cation sorption capacity. It is concluded that the presence of sorbed or fixed NH4 in clays may be detected by infrared (IR) reflectance or emission spectroscopy. Distinction between soluble and sorbed NH4 may be achieved through the presence or absence of several spectral features assigned to the sorbed NH4 moietyi and, specifically, by use of the 4.2 micrometer feature assigned to solution NH4. Thermal analyses furnish supporting evidence of ammonia in our study through detection of N released at temperatures of 270-330 C. Based on these results it is estimated that IR spectra measured from a rover should be able to detect ammonia if present above 20 mg NH4/g sample in the surface layers. Orbital IR spectra and thermal analyses measured on a rover may be able to

  14. FT-IR spectroscopy and DFT calculation study on the solvent effects of benzaldehyde in organic solvents.

    Science.gov (United States)

    Li, Yi; Zhang, Hui; Liu, Qing

    2012-02-01

    FT-IR spectra of benzaldehyde in 11 different organic solvents were recorded and analyzed. The density functional theory (DFT) B3LYP/6-31G* method was chosen to calculate the infrared spectrum of benzaldehyde in gaseous state. The electrostatic effects of different solvents in benzaldehyde solutions were calculated using DFT with the self-consistent isodensity polarizable continuum model (SCI-PCM). Two remarkable carbonyl (C=O) peaks of benzaldehyde were observed by FT-IR in alcohol solvents, which were caused by different hydrogen bond species and explained by ab initio calculation. The results showed that the combination of SCI-PCM model and ab initio calculation could give excellent agreements with FT-IR spectra of title compound in solutions.

  15. Development and application of UV-visible and mid-IR differential absorption spectroscopy techniques for pollutant trace gas monitoring

    OpenAIRE

    Jiménez Pizarro, Rodrigo; Calpini, Bertrand

    2005-01-01

    Spatial representativeness is an important quality criterion in trace gas monitoring, especially if measurements are intended for regulatory and model validation purposes. Open-path absorption spectroscopy techniques meet the representativeness requirement by providing concentrations averaged over atmospheric paths ranging from some hundred meters to some kilometers. This research concerns the characterization and application of a UV-visible differential optical absorption spectroscopy (DOAS)...

  16. Development and application of UV-visible and mid-IR differential absorption spectroscopy techniques for pollutant trace gas monitoring

    OpenAIRE

    Jiménez Pizarro, Rodrigo

    2004-01-01

    Spatial representativeness is an important quality criterion in trace gas monitoring, especially if measurements are intended for regulatory and model validation purposes. Open-path absorption spectroscopy techniques meet the representativeness requirement by providing concentrations averaged over atmospheric paths ranging from some hundred meters to some kilometers. This research concerns the characterization and application of a UV-visible differential optical absorption spectroscopy (DOAS)...

  17. Intense Terahertz Sources for 2D Spectroscopy

    DEFF Research Database (Denmark)

    Pedersen, Pernille Klarskov

    and 2-color air plasmas are investigated, capable of generating high pulse energies i.e. up to several µJ when pumped by fs pulses with energies on the order of ~mJ. Beam profiles are measured with a commercial THz camera, and it is found that the crystalbased sources have Gaussian beams, while the...... has been observed having a Gaussian beam profile. In addition to the intense THz pulses focused in free-space in order to achieve the highest possible field strength, it is shown that resonant microslit arrays can be used to enhance the THz field, and with the possibility of mounting crystalline...... sucrose induced by the intense THz pulses....

  18. Body composition in Mexican adults by air displacement plethysmography (ADP) with the BOD-POD and deuterium oxide dilution using infrared spectroscopy (IRS-DOD).

    Science.gov (United States)

    Macías, Nayeli; Calderón de la Barca, Ana María; Bolaños, Adriana V; Alemán, Heliodoro; Esparza, Julián; Valencia, Mauro E

    2002-09-01

    Thirty four subjects (13 men and 21 women), 24 to 70 years old from northern Mexico, were measured for body density by air displacement plethysmography (ADP) with the BOD-POD, and for total body water by deuterium oxide dilution and infrared spectroscopy (IRS-DOD). Subjects were given a 30 g dose of deuterium oxide. Saliva samples were filtered, sublimated, and deuterium was measured using a Miran 1 FF, IRS. Linear regression of the fat mass (FM) derived from both methods showed that the intercept (0.071) was not different from zero (p = .96) and the slope was 0.96 (p < .0001) demonstrating the techniques to be equivalent. Further, mean FM was 26.7 +/- 12.4 and 25.6 +/- 12.4 kg, for IRS-DOD and ADP techniques, respectively (p = .08). Precision analysis by the model R2 showed that 92.3% of the variability was explained (SEM = 3.4 kg). Bland-Altman analysis showed no significant bias (r = 0.017; p = .93). Mean difference between methods was -1.08 (CI: -2.3 to + 0.13) kg FM.

  19. Studies on the Hydrogenation of Acetonitrile over Fresh Mo2C/γ-Al2O3 Catalyst by In-situ IR Spectroscopy

    Institute of Scientific and Technical Information of China (English)

    Zhang Jing; Wu Weicheng; Liu Chuang; Ding Xiaoguang; Chu Gang; Zhang Jianguo

    2015-01-01

    The adsorption of acetonitrile, the co-adsorption of acetonitrile with CO, and hydrogenation of acetonitrile on fresh Mo2C/γ-Al2O3 catalyst were studied by in situ IR spectroscopy. It was found out that CH3CN exhibited strong interac-tion with the fresh Mo2C/γ-Al2O3 catalyst and was adsorbed mainly on Moδ+sites of fresh Mo2C/γ-Al2O3 catalyst. Moreover, CH3CN could affect the shifting of IR spectra for CO adsorption towards a lower wave number. The IR spectroscopic study on acetonitrile hydrogenation showed that CH3CN could be easily hydrogenated in the presence of H2 on the Mo2C/γ-Al2O3 catalyst. Furthermore, it was observed that CH3CN could be selectively hydrogenated to imines on fresh Mo2C/γ-Al2O3 catalyst. Additionally, the active sites of fresh Mo2C/γ-Al2O3 catalyst might be covered with coke during the hydrogenation reaction of acetonitrile. The treatment of catalyst with hydrogen at 673 K could not completely remove coke deposits on the surface of the Mo2C/γ-Al2O3 catalyst.

  20. Adsorption and oxidation of formaldehyde on a polycrystalline Pt film electrode: An in situ IR spectroscopy search for adsorbed reaction intermediates

    Directory of Open Access Journals (Sweden)

    Zenonas Jusys

    2014-05-01

    Full Text Available As part of a mechanistic study of the electrooxidation of C1 molecules we have systematically investigated the dissociative adsorption/oxidation of formaldehyde on a polycrystalline Pt film electrode under experimental conditions optimizing the chance for detecting weakly adsorbed reaction intermediates. Employing in situ IR spectroscopy in an attenuated total reflection configuration (ATR-FTIRS with p-polarized IR radiation to further improve the signal-to-noise ratio, and using low reaction temperatures (3 °C and deuterium substitution to slow down the reaction kinetics and to stabilize weakly adsorbed reaction intermediates, we could detect an IR absorption band at 1660 cm−1 characteristic for adsorbed formyl intermediates. This assignment is supported by an isotope shift in wave number. Effects of temperature, potential and deuterium substitution on the formation and disappearance of different adsorbed species (COad, adsorbed formate, adsorbed formyl, are monitored and quantified. Consequences on the mechanism for dissociative adsorption and oxidation of formaldehyde are discussed.

  1. Identification of Quercus agrifolia (coast live oak resistant to the invasive pathogen Phytophthora ramorum in native stands using Fourier-transform infrared (FT-IR spectroscopy

    Directory of Open Access Journals (Sweden)

    Anna Olivia Conrad

    2014-10-01

    Full Text Available Over the last two decades coast live oak (CLO dominance in many California coastal ecosystems has been threatened by the alien invasive pathogen Phytophthora ramorum, the causal agent of sudden oak death. In spite of high infection and mortality rates in some areas, the presence of apparently resistant trees has been observed, including trees that become infected but recover over time. However, identifying resistant trees based on recovery alone can take many years. The objective of this study was to determine if Fourier-transform infrared (FT-IR spectroscopy, a chemical fingerprinting technique, can be used to identify CLO resistant to P. ramorum prior to infection. Soft independent modeling of class analogy identified spectral regions that differed between resistant and susceptible trees. Regions most useful for discrimination were associated with carbonyl group vibrations. Additionally, concentrations of two putative phenolic biomarkers of resistance were predicted using partial least squares regression; > 99% of the variation was explained by this analysis. This study demonstrates that chemical fingerprinting can be used to identify resistance in a natural population of forest trees prior to infection with a pathogen. FT-IR spectroscopy may be a useful approach for managing forests impacted by sudden oak death, as well as in other situations where emerging or existing forest pests and diseases are of concern.

  2. Applications of FT-IR spectroscopy to the studies of esterification and crosslinking of cellulose by polycarboxylic acids: Part II. The performance of the crosslinked cotton fabrics

    Science.gov (United States)

    Wei, Weishu; Yang, Charles Q.

    1998-06-01

    Durable press finishing processes are commonly used in the textile industry to produce wrinkle-free cotton fabrics and garments. A durable press finishing agent forms covalent bands with cellulosic hydroxyl groups, thus crosslinking the cellulose molecules. The crosslinking of cellulose increases wrinkle resistance of the treated cotton fabric and reduces fabric mechanical strength. Wrinkle recovery angle (WRA) and tensile strength are the two most important parameters used to evaluate the performance of the crosslinked cotton fabrics and garments. In this study, we investigated the correlation between WRA and tensile strength on one hand, and the amount of crosslinkages formed by the crosslinking agents including dimethyloldihydroxylethyleneurea (DMDHEU) and 1,2,3,4-butanetetracarboxylic acid (BTCA) determined by FT-IR spectroscopy on the other hand. Linear regression curves between the carbonyl band absorbance, and WRA and tensile strength of the treated cotton fabric were developed. The data indicated that FT-IR spectroscopy is a reliable technique for predicting the performance of durable press finished cotton fabrics, therefore can be used as a convenient instrumental method for quality control in the textile and garment industry.

  3. Site-specific thermodynamic stability and unfolding of a de novo designed protein structural motif mapped by 13C isotopically edited IR spectroscopy.

    Science.gov (United States)

    Kubelka, Ginka S; Kubelka, Jan

    2014-04-23

    The mechanism of protein folding remains poorly understood, in part due to limited experimental information available about partially folded states. Isotopically edited infrared (IR) spectroscopy has emerged as a promising method for studying protein structural changes with site-specific resolution, but its full potential to systematically probe folding at multiple protein sites has not yet been realized. We have used (13)C isotopically edited IR spectroscopy to investigate the site-specific thermal unfolding at seven different locations in the de novo designed helix-turn-helix protein αtα. As one of the few stable helix-turn-helix motifs, αtα is an excellent model for studying the roles of secondary and tertiary interactions in folding. Circular dichroism (CD) experiments on the full αtα motif and its two peptide fragments show that interhelical tertiary contacts are critical for stabilization of the secondary structure. The site-specific thermal unfolding probed by (13)C isotopically edited IR is likewise consistent with primarily tertiary stabilization of the local structure. The least thermally stable part of the αtα motif is near the turn where the interhelical contacts are rather loose, while the motif's center with best established core packing has the highest stability. Similar correlation between the local thermal stability and tertiary contacts was found previously for a naturally occurring helix-turn-helix motif. These results underline the importance of native-like tertiary stabilizing interactions in folding, in agreement with recent state-of-the art folding simulations as well as simplified, native-centric models.

  4. 500 nm Continuous Wave Tunable SingleFrequency MidIR Light Source for C–H Spectroscopy

    DEFF Research Database (Denmark)

    Høgstedt, Lasse; Jensen, Ole Bjarlin; Dam, Jeppe Seidelin;

    2012-01-01

    A computer controlled tunable mid-IR light source, based on single resonant difference frequency generation (DFG), is experimentally investigated. The DFG process is pumped by an external cavity tapered diode laser, tunable over a spectral range of 30 nm. Grating feedback to the single mode channel...... of the tapered diode narrows the spectrum and allows for tuning of the emitted spectrum in the range from 780 to 810 nm. The DFG process takes place intra-cavity in a high finesse diode pumped 1064 nm solid state Nd:YVO4 laser cavity, using periodically poled LiNbO3 as the nonlinear material. Based on this new...... approach, a tunable single-frequency output power exceeding 3 mW was obtained in the mid-IR tuning range from 2.9 to 3.4 μm....

  5. Spectroscopy of A˜190 Ir-Pt-Au Nuclei Near Stability from Complete and Incomplete Fusion Reaction

    Science.gov (United States)

    Fang, Y. D.; Zhang, Y. H.; Zhou, X. H.; Liu, M. L.; Wang, J. G.; Guo, Y. X.; Lei, X. G.; Hua, W.; Ma, F.; Wang, S. C.; Gao, B. S.; Li, S. C.; Wu, X. G.; He, C. Y.; Zheng, Y.; Wang, Z. M.; Shi, Y.; Xu, F. R.

    2013-11-01

    High-spin states of 194, 195Au, 195Pt and 193Ir have been studied using an in-beam γ-ray spectroscopic technique following the reaction of 7Li on an 192Os target at 44 MeV. The emitted γ rays were observed using an array of 14 Compton-suppressed HPGe detectors. Several bands in these nuclei have been identified and extended up to high-spin states. The α and t emission channels leading to 193Ir and 195Pt, respectively, are strongly enhanced which may be explained by incomplete fusion reaction; the t and α fragments from the break-up of weakly bound 7Li nucleus fusion with 192Os target.

  6. Spectroscopy and mid-IR lasing of Cr2+ ions in ZnSe/ZnS crystals under visible excitation

    Science.gov (United States)

    Peppers, J.; Konak, T.; Martyshkin, D. V.; Fedorov, V. V.; Mirov, S. B.

    2014-02-01

    Recent efforts have demonstrated efficient Cr2+ :II-VI chalcogenide (e.g. ZnSe, ZnS) broadly tunable (1.9-3.3μm) lasers under direct intra-shell Cr2+ optical excitation. We report on the spectroscopic study of Cr2++:ZnSe/ZnS under visible excitation into the charge transfer band of Cr2+ ions. Polycrystalline samples prepared by thermal diffusion method were studied. Middle-infrared (mid-IR) photo-luminescence (PL) of Cr2+ ions was compared under continuous wave (CW) direct 1532nm (5T2→5E) excitation and under 532nm excitation into charge transfer band. The quantum yield of Cr:ZnSe mid-IR luminescence under CW green excitation was estimated as close to 100% at room temperature. To estimate Cr excitation rate via charge transfer band under short pulse excitation, mid-IR PL kinetic measurements were performed with the use of 532nm picosecond and nanosecond pumping. Mid-IR PL kinetics of Cr:ZnSe under pulsed green excitation exhibit a relatively slow growth reaching a peak at ~5-10μs for nanosecond and picosecond excitations, respectively, while PL kinetics in Cr:ZnS reveal shorter measured rise time (BBO based optical parametric oscillator tunable over 450-700nm. Cr:ZnSe lasing at 2.5μm induced by 2+→1+→2+ ionization transitions of chromium under visible excitation was achieved.

  7. 8-13 micron spectroscopy and IR photometry of Comet P/Brorsen-Metcalf (1989o) near perihelion

    Science.gov (United States)

    Lynch, David K.; Hanner, Martha S.; Russell, Ray W.

    1992-01-01

    Thermal IR spectrophotometry of Comet P/Brorsen-Metcalf near perihelion was obtained during August 28-September 6, 1989, by the NASA IRTF; these data are presently compared with results for Comet P/Halley. The spectra, which lacked silicate emission, are consistent with 400-430 K grey body emission. The grains are on these bases inferred to have been larger than typical for either new comets or P/Halley. Attention is given to the composition, mass, temperature, and character of the cometary dust in view of Comet P/Halley study results.

  8. Study on clathrate formation of schaeffer's complexes with 4-methylpyridine (4-MePy) by IR-spectroscopy method

    International Nuclear Information System (INIS)

    IR-spectra of Schaeffer's complex compounds [M(4-MePy)n(NCS)2] (M-Co(2), Ni(2), Zn(2), Cd(2); n=2 or 4) and their clathrates with 4-MePy have been obtained. These data indicate of the presence both ''free'' and bonded 4-MePy in the structure of clathrates. To put in another way, the enclosing of 4-MePy in the cavities of the host framework takes place without appreciable chemical interaction between the guest and the host, and reforming of crystalline modification doesn't bring to changing of the spectrum in examined area

  9. Proteolytically-induced changes of secondary structural protein conformation of bovine serum albumin monitored by Fourier transform infrared (FT-IR) and UV-circular dichroism spectroscopy

    Science.gov (United States)

    Güler, Günnur; Vorob'ev, Mikhail M.; Vogel, Vitali; Mäntele, Werner

    2016-05-01

    Enzymatically-induced degradation of bovine serum albumin (BSA) by serine proteases (trypsin and α-chymotrypsin) in various concentrations was monitored by means of Fourier transform infrared (FT-IR) and ultraviolet circular dichroism (UV-CD) spectroscopy. In this study, the applicability of both spectroscopies to monitor the proteolysis process in real time has been proven, by tracking the spectral changes together with secondary structure analysis of BSA as proteolysis proceeds. On the basis of the FTIR spectra and the changes in the amide I band region, we suggest the progression of proteolysis process via conversion of α-helices (1654 cm- 1) into unordered structures and an increase in the concentration of free carboxylates (absorption of 1593 and 1402 cm- 1). For the first time, the correlation between the degree of hydrolysis and the concentration of carboxylic groups measured by FTIR spectroscopy was revealed as well. The far UV-CD spectra together with their secondary structure analysis suggest that the α-helical content decreases concomitant with an increase in the unordered structure. Both spectroscopic techniques also demonstrate that there are similar but less spectral changes of BSA for the trypsin attack than for α-chymotrypsin although the substrate/enzyme ratio is taken the same.

  10. Distant analysis of the isotopic composition of H{sub 2}, D{sub 2}, T{sub 2} and H{sub 2}O, D{sub 2}O, T{sub 2}O mixtures by spontaneous Raman spectroscopy; Analyse a distance de la composition isotopique de melanges (H{sub 2}, D{sub 2}, T{sub 2}) et (H{sub 2}O, D{sub 2}O, T{sub 2}O) par spectroscopie Raman spontanee

    Energy Technology Data Exchange (ETDEWEB)

    Chaufour, Y

    1996-01-10

    This work concerns the quantitative analysis of hydrogen isotopes in of H2/D2/T2 and H20/D20/T20 mixtures. The radioactivity of tritium and its nuclear environment explain the need for distant analysis. Spontaneous Raman spectroscopy has been chosen as analytical tool because it can differentiate all the isotopic molecules we are interested in. The possibility to record spectra distantly with optical fibers makes it a good solution for the two cases we are presenting. For tritiated water analysis we have used a multi-fiber probe which penetrates the glovebox and allows to record the water spectrum through the closed glass flask which contains it. In two minutes we can detect 0.56 molar % of H20 and D20, and 0.056 molar % of 120 (1800 i/l). For gaseous hydrogen mixtures we have developed a multipass cell connected to the Raman installation with one hundred meter optical fibers. Each of the six molecular species resulting of isotopic exchanges are detected in two minutes until partial pressures of 2O mbar. (author) 80 refs.

  11. A novel setup for femtosecond pump-repump-probe IR spectroscopy with few cycle CEP stable pulses.

    Science.gov (United States)

    Bradler, Maximilian; Werhahn, Jasper C; Hutzler, Daniel; Fuhrmann, Simon; Heider, Rupert; Riedle, Eberhard; Iglev, Hristo; Kienberger, Reinhard

    2013-08-26

    We present a three-color mid-IR setup for vibrational pump-repump-probe experiments with a temporal resolution well below 100 fs and a freely selectable spectral resolution of 20 to 360 cm(-1) for the pump and repump. The usable probe range without optical realignment is 900 cm(-1). The experimental design employed is greatly simplified compared to the widely used setups, highly robust and includes a novel means for generation of tunable few-cycle pulses with stable carrier-envelope phase. A Ti:sapphire pump system operating with 1 kHz and a modest 150 fs pulse duration supplies the total pump energy of just 0.6 mJ. The good signal-to-noise ratio of the setup allows the determination of spectrally resolved transient probe changes smaller than 6·10(-5) OD at 130 time delays in just 45 minutes. The performance of the spectrometer is demonstrated with transient IR spectra and decay curves of HDO molecules in lithium nitrate trihydrate and ice and a first all MIR pump-repump-probe measurement. PMID:24105560

  12. Development of simple algorithm for direct and rapid determination of cotton maturity from FT-IR spectroscopy

    Science.gov (United States)

    Liu, Yongliang; Thibodeaux, Devron; Gamble, Gary R.

    2011-06-01

    Fourier transform infrared (FT-IR) spectra of seed and lint cottons were collected to explore the potential for the discrimination of immature cottons from mature ones and also for the determination of actual cotton maturity. Spectral features of immature and mature cottons revealed large differences in the 1200-900 cm-1 region, and such spectral distinctions formed the basis on which to develop simple three-band ratio algorithm for classification analysis. Next, an additional formula was created to assess the degree of cotton fiber maturity by converting the three-band ratios into an appropriate FT-IR maturity (MIR) index. Furthermore, the MIR index was compared with parameters derived from traditional image analysis (IA) and advanced fiber information system (AFIS) measurements. Results indicated strong correlations (R2 > 0.89) between MIR and MAFIS and between MIR and MIA among either International Cotton Calibration (ICC) standards or selected cotton maturity references. On the other hand, low correlations between the pairs were observed among regular cotton fibers, which likely resulted from the heterogeneous distribution of structural, physical, and chemical characteristics in cotton fibers and subsequent different sampling specimens for individual and independent measurement.

  13. Absorption Spectroscopy and Imaging from the Visible through Mid-IR with 20 nm Resolution Using AFM probes

    Science.gov (United States)

    Centrone, Andrea

    2015-03-01

    Correlated nanoscale composition and optical property maps are important to engineer nanomaterials in applications ranging from photovoltaics to sensing and therapeutics. Wavelengths (λs) from the visible to near-IR probe electronic transitions in materials, providing information regarding band gap and defects while light in mid-IR probes vibrational transitions and provide chemical composition. However, light diffraction limits the lateral resolution of conventional micro-spectroscopic techniques to approximately λ/2, which is insufficient to image nanomaterials. Additionally, the λ-dependent resolution impedes direct comparison of spectral maps from different spectral ranges. Photo Thermal Induced Resonance (PTIR) is a novel technique that circumvents light diffraction by employing an AFM tip as a local detector for measuring light absorption with λ-independent nanoscale resolution. Our PTIR setup combines an AFM microscope with three lasers providing λ-tunability from 500 nm to 16000 nm continuously. The AFM tip transduces locally the sample thermal expansion induced by light absorption into large cantilever oscillations. Local absorption spectra (electronic or vibrational) and maps are obtained recording the amplitude of the tip deflection as a function of λ and position, respectively. The working principles of the PTIR technique will be described first, and nano-patterned polymer samples will be used to evaluate its lateral resolution, sensitivity and linearity. Results show that the PTIR signal intensity is proportional to the local absorbed energy suggesting applicability of this technique for quantitative chemical analysis at nanoscale, at least for thin (less than 1000 nm thick) samples. Additionally, a λ-independent resolution as high as 20 nm is demonstrated across the whole spectral range. In the second part of the talk, PTIR will be applied to image the dark plasmonic resonance of gold Asymmetric Split Ring Resonators (A-SRRs) in the mid-IR

  14. Flexible attosecond beamline for high harmonic spectroscopy and XUV/near-IR pump probe experiments requiring long acquisition times

    Energy Technology Data Exchange (ETDEWEB)

    Weber, S. J., E-mail: sebastien.weber@cea.fr; Manschwetus, B.; Billon, M.; Bougeard, M.; Breger, P.; Géléoc, M.; Gruson, V.; Lin, N.; Ruchon, T.; Salières, P.; Carré, B. [Commissariat l’Energie Atomique, Laser, Interactions and Dynamics Laboratory (LIDyL), DSM/IRAMIS, CEA-Saclay, 91191 Gif sur Yvette (France); Böttcher, M.; Huetz, A.; Picard, Y. J. [ISMO, UMR 8214, Université Paris-Sud, Batiment 350, Orsay (France)

    2015-03-15

    We describe the versatile features of the attosecond beamline recently installed at CEA-Saclay on the PLFA kHz laser. It combines a fine and very complete set of diagnostics enabling high harmonic spectroscopy (HHS) through the advanced characterization of the amplitude, phase, and polarization of the harmonic emission. It also allows a variety of photo-ionization experiments using magnetic bottle and COLTRIMS (COLd Target Recoil Ion Momentum Microscopy) electron spectrometers that may be used simultaneously, thanks to a two-foci configuration. Using both passive and active stabilization, special care was paid to the long term stability of the system to allow, using both experimental approaches, time resolved studies with attosecond precision, typically over several hours of acquisition times. As an illustration, applications to multi-orbital HHS and electron-ion coincidence time resolved spectroscopy are presented.

  15. Sulfato/thiosulfato reducing bacteria characterization by FT-IR spectroscopy: a new approach to biocorrosion control.

    Science.gov (United States)

    Rubio, Celine; Ott, Christelle; Amiel, Caroline; Dupont-Moral, Isabelle; Travert, Josette; Mariey, Laurence

    2006-03-01

    Sulfato and Thiosulfato Reducing Bacteria (SRB, TRB) can induce corrosion process on steel immersed in seawater. This phenomenon, called biocorrosion, costs approximatively 5 billion euros in France each year. We provide the first evidence that Fourier Transformed InfraRed (FTIR) spectroscopy is a competitive technique to evaluate the sulfurogen flora involved in biocorrosion in comparison with time consuming classical identification methods or PCR analyses. A great discrimination was obtained between SRB, TRB and some contamination bacteria known to be present in seawater and seem to be able to reduce sulfate under particular conditions. Moreover, this preliminary study demonstrates that FTIR spectroscopic and genotypic results present a good correlation (these results are confirmed by other data obtained before or later, data not shown here). The advantages gained by FTIR spectroscopy are to give information on strain phenotype and bacterial metabolism which are of great importance in corrosion processes.

  16. Peer Mentoring in the General Chemistry and Organic Chemistry Laboratories. The Pinacol Rearrangement: An Exercise in NMR and IR Spectroscopy for General Chemistry and Organic Chemistry Laboratories

    Science.gov (United States)

    Arrington, Caleb A.; Hill, Jameica B.; Radfar, Ramin; Whisnant, David M.; Bass, Charles G.

    2008-02-01

    This article describes a discovery experiment for general chemistry and organic chemistry labs. Although the pinacol rearrangement has been employed in undergraduate organic laboratories before, in this application organic chemistry students act as mentors to students of general chemistry. Students work together using distillation—a new technique for the general chemistry students and a basic one for the organic students—to isolate an unknown compound. Then, using spectroscopy (IR and NMR), the students collaborate to determine the structure of the product of the reaction. This application of a standard experiment allows general chemistry students to gain exposure to modern spectroscopic instrumentation and to enhance their problem-solving skills. Organic chemistry students improve their understandings of laboratory techniques and spectroscopic interpretation by acting as the resident experts for the team.

  17. Selective Alcohol Oxidation by a Copper TEMPO Catalyst: Mechanistic Insights by Simultaneously Coupled Operando EPR/UV-Vis/ATR-IR Spectroscopy.

    Science.gov (United States)

    Rabeah, Jabor; Bentrup, Ursula; Stößer, Reinhard; Brückner, Angelika

    2015-09-28

    The first coupled operando EPR/UV-Vis/ATR-IR spectroscopy setup for mechanistic studies of gas-liquid phase reactions is presented and exemplarily applied to the well-known copper/TEMPO-catalyzed (TEMPO=(2,2,6,6-tetramethylpiperidin-1-yl)oxyl) oxidation of benzyl alcohol. In contrast to previous proposals, no direct redox reaction between TEMPO and Cu(I) /Cu(II) has been detected. Instead, the role of TEMPO is postulated to be the stabilization of a (bpy)(NMI)Cu(II) -O2 (⋅-) -TEMPO (bpy=2,2'-bipyridine, NMI=N-methylimidazole) intermediate formed by electron transfer from Cu(I) to molecular O2 . PMID:26174141

  18. High-resolution IR absorption spectroscopy of polycyclic aromatic hydrocarbons in the 3 {\\mu}m region: Role of periphery

    CERN Document Server

    Maltseva, Elena; Candian, Alessandra; Mackie, Cameron J; Huang, Xinchuan; Lee, Timothy J; Tielens, Alexander G G M; Buma, Wybren Jan

    2016-01-01

    In this work we report on high-resolution IR absorption studies that provide a detailed view on how the peripheral structure of irregular polycyclic aromatic hydrocarbons (PAHs) affects the shape and position of their 3 {\\mu}m absorption band. To this purpose we present mass-selected, high-resolution absorption spectra of cold and isolated phenanthrene, pyrene, benz[a]antracene, chrysene, triphenylene, and perylene molecules in the 2950-3150 cm-1 range. The experimental spectra are compared with standard harmonic calculations, and anharmonic calculations using a modified version of the SPECTRO program that incorporates a Fermi resonance treatment utilizing intensity redistribution. We show that the 3 {\\mu}m region is dominated by the effects of anharmonicity, resulting in many more bands than would have been expected in a purely harmonic approximation. Importantly, we find that anharmonic spectra as calculated by SPECTRO are in good agreement with the experimental spectra. Together with previously reported hi...

  19. Hydrophobic Solvation : A 2D IR Spectroscopic Inquest

    NARCIS (Netherlands)

    Bakulin, Artem A.; Liang, Chungwen; Jansen, Thomas La Cour; Wiersma, Douwe A.; Bakker, Huib J.; Pshenichnikov, Maxim S.

    2009-01-01

    For decades, the enigma of the hydrophobic force has captured the imagination of scientists. in particular, Frank and Evans' idea that the hydrophobic effect was mainly due to some kind of "iceberg" formation around a hydrophobic solute stimulated many experiments and molecular dynamics simulation s

  20. Benzyl alcohol-ammonia (1:1) cluster structure investigated by combined IR-UV double resonance spectroscopy in jet and ab initio calculation

    Indian Academy of Sciences (India)

    Nikhil Guchhait

    2001-06-01

    Laser-induced fluorescence excitation and IR-UV double resonance spectroscopy have been used to determine the hydrogen-bonded structure of benzyl alcohol-ammonia (1:1) cluster in a jet-cooled molecular beam. In addition, ab initio quantum chemical calculations have been performed at HF/6-31G and HF/6-31G(d, p) levels for different ground state equilibrium structures of the cluster to correlate the calculated OH and NH frequencies and their intensities with experimental results. The broad red-shifted OH-stretching mode in the IR-UV double resonance spectrum suggests strong hydrogen bonding between the hydroxyl hydrogen and the lone pair of the ammonia nitrogen. The position and intensity distribution of the calculated NH and OH modes for the minimum-energy gauche form at HF/6-31 level have better correlation with the experimental results compared to other calculated ground state equilibrium conformers. These results lead to the conclusion that the minimum energy gauche form of the cluster is populated in the jet-cooled condition.

  1. Molecular orientation behavior of chiral nematic liquid crystals based on the presence of blue phases using polarized microscopic FT-IR spectroscopy

    Science.gov (United States)

    Matsumura, Masanori; Katayama, Norihisa

    2016-07-01

    Study on molecular orientation behavior of highly twisted chiral nematic liquid crystals (N∗LCs) expressing blue phases (BPs) is important for developing new devices. This study examines the change of molecular orientation of N∗LCs due to the presence of BPs. Polarized microscopic FT-IR spectroscopy was used to study the in- and out-of-plane molecular orientations of N∗LCs that undergo a phase transition involving BPs. The band intensity ratio of CN to CH2 stretching modes (CN/CH2) in the IR spectra was used to determine the orientation of N∗LC molecules. The measured spectra indicated that the helical axis of N∗LC molecules was perpendicular to the substrate before heating and inclined on the substrate after cooling the sample which has phase transition from BP I to chiral nematic (N∗). The N∗LC molecule in the cell of rubbed orientation film exhibited the in-plane anisotropy after a heating-cooling ramp only in samples that passed through BP I. These results indicate that the changes of molecular orientation of N∗LC by phase transition are affected by BP I.

  2. IR and SFG vibrational spectroscopy of the water bend in the bulk liquid and at the liquid-vapor interface, respectively

    Energy Technology Data Exchange (ETDEWEB)

    Ni, Yicun; Skinner, J. L. [Theoretical Chemistry Institute and Department of Chemistry, University of Wisconsin, Madison, Wisconsin 53706 (United States)

    2015-07-07

    Vibrational spectroscopy of the water bending mode has been investigated experimentally to study the structure of water in condensed phases. In the present work, we calculate the theoretical infrared (IR) and sum-frequency generation (SFG) spectra of the HOH bend in liquid water and at the water liquid/vapor interface using a mixed quantum/classical approach. Classical molecular dynamics simulation is performed by using a recently developed water model that explicitly includes three-body interactions and yields a better description of the water surface. Ab-initio-based transition frequency, dipole, polarizability, and intermolecular coupling maps are developed for the spectral calculations. The calculated IR and SFG spectra show good agreement with the experimental measurements. In the theoretical imaginary part of the SFG susceptibility for the water liquid/vapor interface, we find two features: a negative band centered at 1615 cm{sup −1} and a positive band centered at 1670 cm{sup −1}. We analyze this spectrum in terms of the contributions from molecules in different hydrogen-bond classes to the SFG spectral density and also compare to SFG results for the OH stretch. SFG of the water bending mode provides a complementary picture of the heterogeneous hydrogen-bond configurations at the water surface.

  3. On the Use of Fourier Transform Infrared (FT-IR) Spectroscopy and Synthetic Calibration Spectra to Quantify Gas Concentrations in a Fischer-Tropsch Catalyst System.

    Science.gov (United States)

    Ferguson, Frank T; Johnson, Natasha M; Nuth, Joseph A

    2015-10-01

    One possible origin of prebiotic organic material is that these compounds were formed via Fischer-Tropsch-type (FTT) reactions of carbon monoxide and hydrogen on silicate and oxide grains in the warm, inner-solar nebula. To investigate this possibility, an experimental system has been built in which the catalytic efficiency of different grain-analog materials can be tested. During such runs, the gas phase above these grain analogs is sampled using Fourier transform infrared (FT-IR) spectroscopy. To provide quantitative estimates of the concentration of these gases, a technique in which high-resolution spectra of the gases are calculated using the High-Resolution Transmission Molecular Absorption (HITRAN) database is used. Next, these spectra are processed via a method that mimics the processes giving rise to the instrumental line shape of the FT-IR spectrometer, including apodization, self-apodization, and broadening due to the finite resolution. The result is a very close match between the measured and computed spectra. This technique was tested using four major gases found in the FTT reactions: carbon monoxide, methane, carbon dioxide, and water. For the ranges typical of the FTT reactions, the carbon monoxide results were found to be accurate to within 5% and the remaining gases accurate to within 10%. These spectra can then be used to generate synthetic calibration data, allowing the rapid computation of the gas concentrations in the FTT experiments. PMID:26449809

  4. FT-IR spectroscopy and density functional theory calculations of 13C isotopologues of the helical peptide Z-Aib6-OtBu.

    Science.gov (United States)

    Zeko, Timothy; Hannigan, Steven F; Jacisin, Timothy; Guberman-Pfeffer, Matthew J; Falcone, Eric R; Guildford, Melissa J; Szabo, Christopher; Cole, Kathryn E; Placido, Jessica; Daly, Erin; Kubasik, Matthew A

    2014-01-01

    Isotope-edited FT-IR spectroscopy is a combined synthetic and spectroscopic method used to characterize local (e.g., residue-level) vibrational environments of biomolecules. We have prepared the 3(10) helical peptide Z-Aib6-OtBu and seven (13)C-enriched analogues that vary only in the number and position(s) of (13)C═O isotopic enrichment. FT-IR spectra of these eight peptides solvated in the nonpolar aprotic solvent dichloromethane have been collected and compared to frequency, intensity, and normal mode results of DFT calculations. Single (13)C enrichment of amide functional groups tends to localize amide I vibrational eigenmodes, providing residue-specific information regarding the local environment (e.g., hydrogen bonding or solvent exposure) of the peptide bond. Double (13)C enrichment of Z-Aib6-OtBu allows for examination of interamide coupling between two labeled amide functional groups, providing experimental evidence of interamide coupling in the context of 3(10) helical structure. Although the calculated and observed interamide couplings of Z-Aib6-OtBu are a few cm(-1) and less, the eight peptides exhibit distinct infrared spectra, revealing details of interamide coupling and residue level vibrational environments.

  5. Implementation of time-resolved step-scan fourier transform infrared (FT-IR) spectroscopy using a kHz repetition rate pump laser.

    Science.gov (United States)

    Magana, Donny; Parul, Dzmitry; Dyer, R Brian; Shreve, Andrew P

    2011-05-01

    Time-resolved step-scan Fourier transform infrared (FT-IR) spectroscopy has been shown to be invaluable for studying excited-state structures and dynamics in both biological and inorganic systems. Despite the established utility of this method, technical challenges continue to limit the data quality and more wide ranging applications. A critical problem has been the low laser repetition rate and interferometer stepping rate (both are typically 10 Hz) used for data acquisition. Here we demonstrate significant improvement in the quality of time-resolved spectra through the use of a kHz repetition rate laser to achieve kHz excitation and data collection rates while stepping the spectrometer at 200 Hz. We have studied the metal-to-ligand charge transfer excited state of Ru(bipyridine)(3)Cl(2) in deuterated acetonitrile to test and optimize high repetition rate data collection. Comparison of different interferometer stepping rates reveals an optimum rate of 200 Hz due to minimization of long-term baseline drift. With the improved collection efficiency and signal-to-noise ratio, better assignments of the MLCT excited-state bands can be made. Using optimized parameters, carbonmonoxy myoglobin in deuterated buffer is also studied by observing the infrared signatures of carbon monoxide photolysis upon excitation of the heme. We conclude from these studies that a substantial increase in performance of ss-FT-IR instrumentation is achieved by coupling commercial infrared benches with kHz repetition rate lasers.

  6. Activated sludge model No. 2d, ASM2d

    DEFF Research Database (Denmark)

    Henze, M.

    1999-01-01

    The Activated Sludge Model No. 2d (ASM2d) presents a model for biological phosphorus removal with simultaneous nitrification-denitrification in activated sludge systems. ASM2d is based on ASM2 and is expanded to include the denitrifying activity of the phosphorus accumulating organisms (PAOs...

  7. Rapid discrimination of cultivated Codonopsis lanceolata in different ages by FT-IR and 2DCOS-IR

    Science.gov (United States)

    Zhu, Yun; Xu, Chang-hua; Huang, Jian; Li, Guo-yu; Liu, Xin-Hu; Sun, Su-qin; Wang, Jin-hui

    2014-07-01

    Deodeok (Codonopsis lanceolata) root, a traditional Chinese herbal medicine, has been used to treat lung ailments, rheumatism, menstrual disturbance and bruises with a long history in China and some other Asian countries. In this study, four types of Deodeok with different growth years were discriminated and identified by a Tri-step infrared spectroscopy method (Fourier transform-infrared spectroscopy (conventional FT-IR) coupled with second derivative infrared spectroscopy (SD-IR) and two dimensional correlation infrared spectroscopy(2DCOS-IR) under thermal perturbation. Although only small differences were found in the FT-IR spectra of the samples, the positions and intensities of peaks around 1736, 1634, 1246, 1055, 1033, 818, 779 cm-1 could be considered as the key factors for discriminating them. The differences among them were amplified by their SD-IR spectra. The 2DCOS-IR spectra provided obvious dynamic chemical structure information of Deodeok samples, which present different particular auto peak clusters in the range of 875-1130 cm-1 and 1170-1630 cm-1, respectively. It was demonstrated that the content of triterpene were decreasing when C. lanceolata were growing older, but the relative content of saccharides initially increased and decreased significantly afterwards. It indicated a general trend that the content of polysaccharides accumulated with increasing years. Specifically, the content of polysaccharides accumulated in the root of 2-year-old plant was the lowest, 4-years-old was the highest, and then the content decreased gradually. Furthermore, according to the differences of locations and intensities of auto-peaks in 2D-IR spectra, the integral changes of components were revealed. This study offers a promising method inherent with cost-effective and time-saving to characterize and discriminate the complicated system like Deodeok.

  8. Time-Resolved FT-IR Spectroscopy of CO Hydrogenation overSupported Ru Catalyst at 700K

    Energy Technology Data Exchange (ETDEWEB)

    Wasylenko, Walter; Frei, Heinz

    2006-02-13

    Time-resolved FT-IR spectra of carbon monoxide hydrogenation over alumina-supported ruthenium were recorded on the millisecond timescale at 703 K using various H{sub 2} concentrations (1 atm total pressure). Adsorbed carbon monoxide was detected along with gas phase products methane (3016 and 1306 cm{sup -1}), water (sharp bands from 1900 - 1300 cm{sup -1}), and carbon dioxide (2348 cm{sup -1}). No other surface species were detected other than adsorbed carbon monoxide. The rate of formation of methane (2.5 {+-} 0.4 s{sup -1}) coincides with the rate of formation of carbon dioxide (3.4 {+-} 0.6 s{sup -1}), and bands due to water are observed to grow in over time. These results establish that methane and carbon dioxide originate from the same intermediate. The adsorbed carbon monoxide band is broad and unsymmetrical with a maximum at 2010 cm{sup -1} in spectra observed at 36 ms that shifts over 3000 ms to 1960 cm{sup -1} due to decreasing amounts of adsorbed carbon monoxide. Kinetic analysis of the adsorbed carbon monoxide band reveals that only a portion of the band can be temporally linked to gas phase products that we observe over the first 1000 ms of catalysis. This result suggests that we are observing dispersive kinetics, which is most likely due to heterogeneity of the surface environment.

  9. Thermodynamics of hydrogen bonding of weak bases in alcohol solutions: Calorimetry of solution, IR-spectroscopy and vapor pressure analysis

    Science.gov (United States)

    Zaitseva, Ksenia V.; Varfolomeev, Mikhail A.; Solomonov, Boris N.

    2012-06-01

    The properties of solutes and their reactivity in aliphatic alcohols significantly depend on the formation of hydrogen bonds. In this work, calorimetric, FTIR-spectroscopic and gas chromatographic vapor pressure studies of hydrogen bonds of weak bases in solution of aliphatic alcohols were carried out. Enthalpies of solutions at infinite dilution of ketones, nitriles and acetates in methanol and octan-1-ol were measured. Obtained from the calorimetric data, the enthalpies of specific interaction of weak bases in aliphatic alcohols unexpectedly found to be positive. IR spectra of solutions of ketones in aliphatic alcohols at infinite dilution were measured at different temperatures. Enthalpies of specific interaction in studied systems obtained from the spectroscopic data confirmed the endothermic process and are in good agreement with calorimetric results. Gibbs energies and entropies of specific interaction of weak bases in aliphatic alcohols were determined. Obtained results show, that the hydrogen bonding process of weak bases in aliphatic alcohols differs substantially from the formation of complexes 1:1 ROH⋯B (B - weak proton acceptor) in aprotic media. The complicated process of hydrogen bonding of weak bases in aliphatic alcohols apparently is controlled by the entropy factor, because these values are above zero.

  10. Structural studies of some phospho-borate glasses using ultrasonic pulse-echo technique, DSC and IR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Gaafar, M.S., E-mail: mohamed_s_gaafar@hotmail.co [Ultrasonic Laboratory, National Institute for Standards, Tersa Street, P.O. Box 136, El-Haram, El-Giza 12211 (Egypt); Afifi, H.A. [Ultrasonic Laboratory, National Institute for Standards, Tersa Street, P.O. Box 136, El-Haram, El-Giza 12211 (Egypt); Mekawy, M.M. [Thermometry Laboratory, National Institute for Standards, Tersa Street, P.O. Box 136, El-Haram, El-Giza 12211 (Egypt)

    2009-06-01

    Glasses in the system (95-x) [0.25 Na{sub 2}O-0.75 B{sub 2}O{sub 3}]-x P{sub 2}O{sub 5}-5 Fe{sub 2}O{sub 3} (0<=x<=15 mol%), have been prepared by the melt quenching technique. Elastic properties and FT-IR spectroscopic studies have been employed to study the role of P{sub 2}O{sub 5} on the structure of the glass system. Elastic properties Poisson's ratio, micro-hardness and Debye temperature have been investigated using sound wave velocity measurements at 4 MHz (both longitudinal and shear) at room temperature. The results showed that the density and the molar volume increase as both sound velocities and the determined glass transition temperatures decrease with increasing the contents of P{sub 2}O{sub 5}. Infrared spectra of the glasses reveal that the borate network consists of diborate units and is affected by the increase in the concentration of P{sub 2}O{sub 5} content as a second network former. These results are interpreted in terms of the replacement of the diborate units with B-O-B bridges by phosphate units with non-bridging oxygens (NBOs). Therefore, the elastic moduli are observed to decrease with the increase in P{sub 2}O{sub 5} content.

  11. Near-IR integral field spectroscopy of ionizing stars and young stellar objects on the borders of HII regions

    CERN Document Server

    Martins, F; Deharveng, L; Zavagno, A; Bouret, J -C

    2009-01-01

    We present near-IR SINFONI observations of three Galactic HII regions: RVW79, RCW82 and RCW120. We identify the ionizing stars of each region: they are early to late O stars, close to the main sequence. We derive their stellar and wind properties using atmosphere models computed with the code CMFGEN. The cluster ionizing RCW~79 formed 2.3+/-0.5 Myr ago. Similar ages are estimated, albeit with a larger uncertainty, for the ionizing stars of the other two regions. In RCW79 the mechanical wind luminosity represents only 0.1% of the ionizing luminosity, questioning the influence of stellar winds on the dynamics of the the HII region. The young stellar objects show four main types of spectral features: H2 emission, Br gamma emission, CO bandheads emission and CO bandheads absorption. These features are typical of young stellar objects surrounded by disks and/or envelopes. The radial velocities of most YSOs are consistent with that of the ionized gas, firmly establishing that star formation is taking place on the b...

  12. Living Matter Observations with a Novel Hyperspectral Supercontinuum Confocal Microscope for VIS to Near-IR Reflectance Spectroscopy

    Directory of Open Access Journals (Sweden)

    Francesca R. Bertani

    2013-10-01

    Full Text Available A broad range hyper-spectroscopic microscope fed by a supercontinuum laser source and equipped with an almost achromatic optical layout is illustrated with detailed explanations of the design, implementation and data. The real novelty of this instrument, a confocal spectroscopic microscope capable of recording high resolution reflectance data in the VIS-IR spectral range from about 500 nm to 2.5 μm wavelengths, is the possibility of acquiring spectral data at every physical point as defined by lateral coordinates, X and Y, as well as at a depth coordinate, Z, as obtained by the confocal optical sectioning advantage. With this apparatus we collect each single scanning point as a whole spectrum by combining two linear spectral detector arrays, one CCD for the visible range, and one InGaAs infrared array, simultaneously available at the sensor output channel of the home made instrument. This microscope has been developed for biomedical analysis of human skin and other similar applications. Results are shown illustrating the technical performances of the instrument and the capability in extracting information about the composition and the structure of different parts or compartments in biological samples as well as in solid statematter. A complete spectroscopic fingerprinting of samples at microscopic level is shown possible by using statistical analysis on raw data or analytical reflectance models based on Abelés matrix transfer methods.

  13. Seasonal Variability of Saturn's Tropospheric Temperatures, Winds and Para-H$_2$ from Cassini Far-IR Spectroscopy

    CERN Document Server

    Fletcher, Leigh N; Achterberg, Richard K; Orton, Glenn S; Flasar, F Michael

    2015-01-01

    Far-IR 16-1000 $\\mu$m spectra of Saturn's hydrogen-helium continuum measured by Cassini's Composite Infrared Spectrometer (CIRS) are inverted to construct a near-continuous record of upper tropospheric (70-700 mbar) temperatures and para-H$_2$ fraction as a function of latitude, pressure and time for a third of a Saturnian year (2004-2014, from northern winter to northern spring). The thermal field reveals evidence of reversing summertime asymmetries superimposed onto the belt/zone structure. The temperature structure that is almost symmetric about the equator by 2014, with seasonal lag times that increase with depth and are qualitatively consistent with radiative climate models. Localised heating of the tropospheric hazes (100-250 mbar) create a distinct perturbation to the temperature profile that shifts in magnitude and location, declining in the autumn hemisphere and growing in the spring. Changes in the para-H$_2$ ($f_p$) distribution are subtle, with a 0.02-0.03 rise over the spring hemisphere (200-500 ...

  14. Structural studies of some phospho-borate glasses using ultrasonic pulse-echo technique, DSC and IR spectroscopy

    International Nuclear Information System (INIS)

    Glasses in the system (95-x) [0.25 Na2O-0.75 B2O3]-x P2O5-5 Fe2O3 (0≤x≤15 mol%), have been prepared by the melt quenching technique. Elastic properties and FT-IR spectroscopic studies have been employed to study the role of P2O5 on the structure of the glass system. Elastic properties Poisson's ratio, micro-hardness and Debye temperature have been investigated using sound wave velocity measurements at 4 MHz (both longitudinal and shear) at room temperature. The results showed that the density and the molar volume increase as both sound velocities and the determined glass transition temperatures decrease with increasing the contents of P2O5. Infrared spectra of the glasses reveal that the borate network consists of diborate units and is affected by the increase in the concentration of P2O5 content as a second network former. These results are interpreted in terms of the replacement of the diborate units with B-O-B bridges by phosphate units with non-bridging oxygens (NBOs). Therefore, the elastic moduli are observed to decrease with the increase in P2O5 content.

  15. Infrared Spectroscopy with ab initio molecular dynamics simulations : gas phase floppy peptides of increasing size and complexity, in relation with IR-MPD experiments

    Science.gov (United States)

    Gaigeot, Marie-Pierre

    2009-03-01

    We present finite temperature DFT-based Car-Parrinello molecular dynamics (MD) simulations for the calculation of infrared spectra of complex molecular systems, either in the gas phase or in the condensed phase. We will review the fundamentals of the method, as well as the applicability and originality of finite temperature MD simulations for the purpose of modeling infrared spectra. Illustrations are taken from the infrared spectroscopy of alanine peptides of increasing size and complexity (from dipeptides to an octo-peptide) in the gas phase, in relation with IR-MPD (Infrared Multi Photon Dissociation) experiments : 300-400 K gas-phase action spectroscopy as devised on the CLIO platform at the University of Orsay-France or on the platform developed in the group of L. Snoek at Oxford-UK. A special emphasis on vibrational anharmonicities and how they can be extracted from molecular dynamics simulations will be put forward. Furthermore, band assignments in terms of atomic movements from MD is challenging and we have introduced a general method for obtaining effective normal modes of molecular systems from MD simulations.

  16. Exoplanet Science with the European Extremely Large Telescope. The Case for Visible and Near-IR Spectroscopy at High Resolution

    CERN Document Server

    Udry, S; Bouchy, F; Cameron, A Collier; Henning, T; Mayor, M; Pepe, F; Piskunov, N; Pollacco, D; Queloz, D; Quirrenbach, A; Rauer, H; Rebolo, R; Santos, N C; Snellen, I; Zerbi, F

    2014-01-01

    Exoplanet science is booming. In 20 years our knowledge has expanded considerably, from the first discovery of a Hot Jupiter, to the detection of a large population of Neptunes and super-Earths, to the first steps toward the characterization of exoplanet atmospheres. Between today and 2025, the field will evolve at an even faster pace with the advent of several space-based transit search missions, ground-based spectrographs, high-contrast imaging facilities, and the James Webb Space Telescope. Especially the ESA M-class PLATO mission will be a game changer in the field. From 2024 onwards, PLATO will find transiting terrestrial planets orbiting within the habitable zones of nearby, bright stars. These objects will require the power of Extremely Large Telescopes (ELTs) to be characterized further. The technique of ground-based high-resolution spectroscopy is establishing itself as a crucial pathway to measure chemical composition, atmospheric structure and atmospheric circulation in transiting exoplanets. A hig...

  17. Component analysis and growth process of nasopharyngeal calculus as revealed by Fourier transform infrared (FT-IR) spectroscopy.

    Science.gov (United States)

    Ogawa, T; Shibata, A; Maeda, Y; Uno, Y; Okano, M; Nishizaki, K; Ohsaki, K

    2003-06-01

    A quite rare case of nasopharyngeal calculus in a woman in her twenties associated with the nasal discharge of pseudomonas infection was reported. As the substance was irregularly large in size, we extracted it partially by piecemeal resection using forceps and also by cracking technique using the holmium yttrium-aluminum-garnet (YAG) laser, under saline irrigation and stereotactic microscopic navigator (SMN) system under endoscopic observation. The substance was firmly fixed to the pharyngeal tonsil bed. The final extract was a small piece of singly folded bandage, which is probably the focal background for calculus formation. In a cross section of calculus specimen removed during surgery, Fourier transform infrared (FT-IR) analysis revealed that a) signal ratio of methylene group (organic substance) to amide I (protein) was 21.6% at the nasal cavity side, gradually decreased toward nasal mucous membrane showing approximate 50%, b) signal ratio of amide I to P04(3-) (inorganic substance) ranged between 17.7% and 26.7% at the different sites and inside the calculus, the protein content was approximate 1/5 of the inorganic substance, and c) signal ratio of the methylene group to amide I at the nasal cavity site showed that their contents were almost equal. The quantity of the organic substance was estimated at approximate 1/2 quantity of the protein at both the central part and the part contacted with the mucous membrane. From these results, it seems that throughout the course of calculus growth, both inorganic substance and protein remain almost constant inside the calculus, while organic substance is released from the internal part of the calculus being probably formed at an early stage. PMID:12899453

  18. FT-IR spectroscopy as a tool for the study of the quality of processed meat products

    Directory of Open Access Journals (Sweden)

    Murcia, M. Antonia

    1994-10-01

    Full Text Available Attenuated total reflectance Fourier transform infrared spectroscopy has been used to characterize processed meat products. Proteins were estimated through the amide I band centered at 1650 cm-1 and lipids through the carbonyl stretching band at 1735 cm-1.
    Estimations of protein/lipid ratios were obtained by dividing the area under the 1650 cm-1 band by the area under the 1735 cm-1 band. These protein/lipid ratios correlated well with those obtained for the same samples using conventional chemical analysis. Attenuated total reflectance Fourier transform infrared spectroscopy is therefore a quick and analytical technique with the advantage over other procedures of being non destructive and which can be used to assess the quality of processed meat products.

    Se ha utilizado la espectroscopia de infrarrojo de transformada de Fourier por reflectancia total atenuada para caracterizar productos cárnicos procesados. Las proteínas se valoraron a través de la banda amida I centrada a 1650 cm-1 y los lípidos por la banda de tensión del carbonilo a 1735 cm-1.
    Los valores de los cocientes proteína/lípido fueron calculados dividiendo el área bajo la banda a 1650 cm-1 por el área bajo la banda a 1735 cm-1. Los cocientes proteína/lípido se correlacionan bien con aquellos obtenidos para las mismas muestras usando análisis químicos convencionales. La espectroscopia de infrarrojo de transformada de Fourier por reflectancia total atenuada es una técnica analítica rápida y con la ventaja sobre otros métodos de ser no destructiva, que puede ser usada para determinar la calidad de productos cárnicos procesados.

  19. Seasonal variability of Saturn's tropospheric temperatures, winds and para-H2 from Cassini far-IR spectroscopy

    Science.gov (United States)

    Fletcher, Leigh N.; Irwin, P. G. J.; Achterberg, R. K.; Orton, G. S.; Flasar, F. M.

    2016-01-01

    Far-IR 16-1000 μ m spectra of Saturn's hydrogen-helium continuum measured by Cassini's Composite Infrared Spectrometer (CIRS) are inverted to construct a near-continuous record of upper tropospheric (70-700 mbar) temperatures and para-H2 fraction as a function of latitude, pressure and time for a third of a saturnian year (2004-2014, from northern winter to northern spring). The thermal field reveals evidence of reversing summertime asymmetries superimposed onto the belt/zone structure. The temperature structure is almost symmetric about the equator by 2014, with seasonal lag times that increase with depth and are qualitatively consistent with radiative climate models. Localised heating of the tropospheric hazes (100-250 mbar) create a distinct perturbation to the temperature profile that shifts in magnitude and location, declining in the autumn hemisphere and growing in the spring. Changes in the para-H2 (fp) distribution are subtle, with a 0.02-0.03 rise over the spring hemisphere (200-500 mbar) perturbed by (i) low-fp air advected by both the springtime storm of 2010 and equatorial upwelling; and (ii) subsidence of high-fp air at northern high latitudes, responsible for a developing north-south asymmetry in fp . Conversely, the shifting asymmetry in the para-H2 disequilibrium primarily reflects the changing temperature structure (and hence the equilibrium distribution of fp), rather than actual changes in fp induced by chemical conversion or transport. CIRS results interpolated to the same point in the seasonal cycle as re-analysed Voyager-1 observations (early northern spring) show qualitative consistency from year to year (i.e., the same tropospheric asymmetries in temperature and fp), with the exception of the tropical tropopause near the equatorial zones and belts, where downward propagation of a cool temperature anomaly associated with Saturn's stratospheric oscillation could potentially perturb tropopause temperatures, para-H2 and winds. Quantitative

  20. Seasonal variability of Saturn's tropospheric temperatures, winds and para-H2 from Cassini far-IR spectroscopy

    Science.gov (United States)

    Fletcher, Leigh N.; Irwin, P. G. J.; Achterberg, R. K.; Orton, G. S.; Flasar, F. M.

    2016-01-01

    Far-IR 16-1000 μ m spectra of Saturn's hydrogen-helium continuum measured by Cassini's Composite Infrared Spectrometer (CIRS) are inverted to construct a near-continuous record of upper tropospheric (70-700 mbar) temperatures and para-H2 fraction as a function of latitude, pressure and time for a third of a saturnian year (2004-2014, from northern winter to northern spring). The thermal field reveals evidence of reversing summertime asymmetries superimposed onto the belt/zone structure. The temperature structure is almost symmetric about the equator by 2014, with seasonal lag times that increase with depth and are qualitatively consistent with radiative climate models. Localised heating of the tropospheric hazes (100-250 mbar) create a distinct perturbation to the temperature profile that shifts in magnitude and location, declining in the autumn hemisphere and growing in the spring. Changes in the para-H2 (fp) distribution are subtle, with a 0.02-0.03 rise over the spring hemisphere (200-500 mbar) perturbed by (i) low-fp air advected by both the springtime storm of 2010 and equatorial upwelling; and (ii) subsidence of high-fp air at northern high latitudes, responsible for a developing north-south asymmetry in fp . Conversely, the shifting asymmetry in the para-H2 disequilibrium primarily reflects the changing temperature structure (and hence the equilibrium distribution of fp), rather than actual changes in fp induced by chemical conversion or transport. CIRS results interpolated to the same point in the seasonal cycle as re-analysed Voyager-1 observations (early northern spring) show qualitative consistency from year to year (i.e., the same tropospheric asymmetries in temperature and fp), with the exception of the tropical tropopause near the equatorial zones and belts, where downward propagation of a cool temperature anomaly associated with Saturn's stratospheric oscillation could potentially perturb tropopause temperatures, para-H2 and winds. Quantitative

  1. The physical nature of the 8 o'clock arc based on near-IR IFU spectroscopy with SINFONI

    CERN Document Server

    Shirazi, M; Nesvadba, N; Allam, S; Brinchmann, J; Tucker, D

    2013-01-01

    We present an analysis of near-infrared integral field unit spectroscopy for the gravitationally lensed Lyman break galaxy, the 8 o'clock arc, taken with SINFONI on the Very Large Telescope. We explore the shape of the spatially-resolved H\\beta\\ profile and demonstrate that we can decompose it into three main components that partially overlap (spatially) but are distinguishable when we include the dynamical information. To study the de-lensed morphology of the galaxy we make use of existing B & H imaging from the Hubble Space Telescope and construct a rigorous lens model using a Bayesian grid based lens modeling technique. We apply this lens model to the SINFONI data cube to construct the de-lensed H\\beta\\ line map and the velocity and velocity dispersion maps of the galaxy. We explore the dynamical state of the galaxy and find that the 8 o'clock arc has a complex velocity field that is not simply explained by a single rotating disk. The H\\beta\\ profile of the galaxy shows a blue-shifted wing suggesting g...

  2. Low-volume, fast response-time hollow silica waveguide gas cells for mid-IR spectroscopy.

    Science.gov (United States)

    Francis, Daniel; Hodgkinson, Jane; Livingstone, Beth; Black, Paul; Tatam, Ralph P

    2016-09-01

    Hollow silica waveguides (HSWs) are used to produce long path length, low-volume gas cells, and are demonstrated with quantum cascade laser spectroscopy. Absorption measurements are made using the intrapulse technique, which allows measurements to be made across a single laser pulse. Simultaneous laser light and gas coupling is achieved through the modification of commercially available gas fittings with low dead volume. Three HSW gas cell configurations with different path lengths and internal diameters are analyzed and compared with a 30 m path length astigmatic Herriott cell. Limit of detection measurements are made for the gas cells using methane at a wavelength 7.82 μm. The lowest limit of detection was provided by HSW with a bore diameter of 1000 μm and a path length of 5 m and was measured to be 0.26 ppm, with a noise equivalent absorbance of 4.1×10-4. The long-term stability of the HSW and Herriott cells is compared through analysis of the Allan-Werle variance of data collected over a 24 h period. The response times of the HSW and Herriott cells are measured to be 0.8 s and 36 s, respectively. PMID:27607251

  3. Optical and near-IR spectroscopy of candidate red galaxies in two z~2.5 proto-clusters

    CERN Document Server

    Doherty, Michelle; De Breuck, Carlos; Ly, Chun; Kodama, Tadayuki; Kurk, Jaron; Seymour, Nick; Vernet, Joel; Stern, Daniel; Venemans, Bram; Kajisawa, Masaru; Tanaka, Ichi

    2009-01-01

    We present a spectroscopic campaign to follow-up red colour-selected candidate massive galaxies in two high redshift proto-clusters surrounding radio galaxies. We observed a total of 57 galaxies in the field of MRC0943-242 (z=2.93) and 33 in the field of PKS1138-262 (z=2.16) with a mix of optical and near-infrared multi-object spectroscopy. We confirm two red galaxies in the field of PKS1138-262 at the redshift of the radio galaxy. Based on an analysis of their spectral energy distributions, and their derived star formation rates from the H-alpha and 24um flux, one object belongs to the class of dust-obscured star-forming red galaxies, while the other is evolved with little ongoing star formation. This result represents the first red and mainly passively evolving galaxy to be confirmed as companion galaxies in a z>2 proto-cluster. Both red galaxies in PKS1138-262 are massive, of the order of 4-6x10^11 M_Sol. They lie along a Colour-Magnitude relation which implies that they formed the bulk of their stellar po...

  4. Differentiation and quality estimation of Cordyceps with infrared spectroscopy

    Science.gov (United States)

    Yang, Ping; Song, Ping; Sun, Su-Qin; Zhou, Qun; Feng, Shu; Tao, Jia-Xun

    2009-11-01

    Heretofore, a scientific and systemic method for differentiation and quality estimation of a well-known Chinese traditional medicine, 'Cordyceps', has not been established in modern market. In this paper, Fourier-transform infrared spectroscopy (FTIR) and two-dimensional correlation infrared spectroscopy (2D-IR) are employed to propose a method for analysis of Cordyceps. It has presented that IR spectra of real Cordyceps of different origins and counterfeits have their own macroscopic fingerprints, with discriminated shapes, positions and intensities. Their secondary derivative spectra can amplify the differences and confirm the potentially characteristic IR absorption bands 1400-1700 cm -1 to be investigated in 2D-IR. Many characteristic fingerprints are discovered in 2D-IR spectra in the range of 1400-1700 cm -1 and hetero 2D spectra of 670-780 cm -1 × 1400-1700 cm -1. The different fingerprints display different chemical constitutes. Through the three steps, different Cordyceps and their counterfeits can be discriminated effectively and their qualities distinctly display. Successful analysis of eight Cordyceps capsule products has proved the practicability of the method, which can also be applied to the quality estimation of other Chinese traditional medicines.

  5. Doppler-free spectroscopy measurement of isotope shifts and hyperfine components of near-IR xenon and krypton transitions

    International Nuclear Information System (INIS)

    Xenon and krypton are used as propellant gas in electric thrusters, in which ejection of corresponding ions produces the desired thrust. As such gases contain several isotopes, a non-intrusive determination of the velocity distribution function of atoms and ions by absorption or LIF requires a precise knowledge of the line structures. We use Doppler-free Lamb-dip spectroscopy to determine isotope shifts and hyperfine structures of odd isotopes of spectral lines of Xe and Kr atoms and Xe+ ion in the 805-835 nm range. Xenon and krypton are currently used as propellant gas in electric thrusters. The latter are considered as a promising concept for space applications owing to propellant mass savings and a high efficiency level. A Hall Effect Thruster (HET) can be seen as a hollow annular ceramic channel confining a magnetized low pressure DC discharge generated between an external hollow cathode and an anode. Electrons emitted from the cathode are trapped around Larmor orbits and experience an azimuthal drift. The resulting low electron mobility induces a strong electric field that is concentrated in a restricted area. The propellant gas, which is fed through the anode, is efficiently ionized by trapped electrons. Created ions are instantly accelerated along the thruster axis by the local electric field. A profound understanding of physical phenomena governing the plasma dynamics inside a HET necessitates to accurately measure the gas temperature, the ion velocity and the magnetic field magnitude during thrusters' operation. In order not to modify thruster plasma properties, these three quantities may be determined by means of laser-aided diagnostics allowing Doppler broadening, Doppler shift and Zeeman splitting measurement of Xe and Kr lines. However, due to the existence of Xe and Kr isotopes, some with non-zero nuclear spin, such measurements require a precise knowledge of the hyperfine structure of considered optical transitions. The hyperfine structure of a

  6. Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hellman, Hal

    1968-01-01

    This booklet discusses spectroscopy, the study of absorption of radiation by matter, including X-ray, gamma-ray, microwave, mass spectroscopy, as well as others. Spectroscopy has produced more fundamental information to the study of the detailed structure of matter than any other tools.

  7. Analysis of crystallized lactose in milk powder by Fourier-transform infrared spectroscopy combined with two-dimensional correlation infrared spectroscopy

    Science.gov (United States)

    Lei, Yu; Zhou, Qun; Zhang, Yan-ling; Chen, Jian-bo; Sun, Su-qin; Noda, Isao

    2010-06-01

    Infrared (IR) spectroscopy is used in combination with two-dimensional (2D) correlation IR spectroscopy to conduct rapid non-destructive quantitative research in milk powder without additional separation steps. The experiments conducted in both FT-IR and 2D FT-IR spectra suggest that characteristic spectroscopic features of milk powder containing different carbohydrate can be detected, and then determine the type of carbohydrate. To predict the approximate content of lactose while the carbohydrate is lactose, different amount of crystallized lactose has been added to the reference milk powder. The correlation coefficient could be used to determine the content of crystallized lactose in milk powder. The method provides a rapid and convenient means for assessing the quality of milk powder.

  8. Spectroscopy

    CERN Document Server

    Walker, S

    1976-01-01

    The three volumes of Spectroscopy constitute the one comprehensive text available on the principles, practice and applications of spectroscopy. By giving full accounts of those spectroscopic techniques only recently introduced into student courses - such as Mössbauer spectroscopy and photoelectron spectroscopy - in addition to those techniques long recognised as being essential in chemistry teaching - sucha as e.s.r. and infrared spectroscopy - the book caters for the complete requirements of undergraduate students and at the same time provides a sound introduction to special topics for graduate students.

  9. Regeneration of LOHC dehydrogenation catalysts: In-situ IR spectroscopy on single crystals, model catalysts, and real catalysts from UHV to near ambient pressure

    Science.gov (United States)

    Amende, Max; Kaftan, Andre; Bachmann, Philipp; Brehmer, Richard; Preuster, Patrick; Koch, Marcus; Wasserscheid, Peter; Libuda, Jörg

    2016-01-01

    The Liquid Organic Hydrogen Carrier (LOHC) concept offers an efficient route to store hydrogen using organic compounds that are reversibly hydrogenated and dehydrogenated. One important challenge towards application of the LOHC technology at a larger scale is to minimize degradation of Pt-based dehydrogenation catalysts during long-term operation. Herein, we investigate the regeneration of Pt/alumina catalysts poisoned by LOHC degradation. We combine ultrahigh vacuum (UHV) studies on Pt(111), investigations on well-defined Pt/Al2O3 model catalysts, and near-ambient pressure (NAP) measurements on real core-shell Pt/Al2O3 catalyst pellets. The catalysts were purposely poisoned by reaction with the LOHC perhydro-dibenzyltoluene (H18-MSH) and with dicyclohexylmethane (DCHM) as a simpler model compound. We focus on oxidative regeneration under conditions that may be applied in real dehydrogenation reactors. The degree of poisoning and regeneration under oxidative reaction conditions was quantified using CO as a probe molecule and measured by infrared reflection-absorption spectroscopy (IRAS) and diffuse reflectance Fourier transform IR spectroscopy (DRIFTS) for planar model systems and real catalysts, respectively. We find that regeneration strongly depends on the composition of the catalyst surface. While the clean surface of a poisoned Pt(111) single crystal is fully restored upon thermal treatment in oxygen up to 700 K, contaminated Pt/Al2O3 model catalyst and core-shell pellet were only partially restored under the applied reaction conditions. Whereas partial regeneration on facet-like sites on supported catalysts is more facile than on Pt(111), carbonaceous deposits adsorbed at low-coordinated defect sites impede full regeneration of the Pt/Al2O3 catalysts.

  10. Two-dimensional vibrational-electronic spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Courtney, Trevor L.; Fox, Zachary W.; Slenkamp, Karla M.; Khalil, Munira, E-mail: mkhalil@uw.edu [Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195 (United States)

    2015-10-21

    Two-dimensional vibrational-electronic (2D VE) spectroscopy is a femtosecond Fourier transform (FT) third-order nonlinear technique that creates a link between existing 2D FT spectroscopies in the vibrational and electronic regions of the spectrum. 2D VE spectroscopy enables a direct measurement of infrared (IR) and electronic dipole moment cross terms by utilizing mid-IR pump and optical probe fields that are resonant with vibrational and electronic transitions, respectively, in a sample of interest. We detail this newly developed 2D VE spectroscopy experiment and outline the information contained in a 2D VE spectrum. We then use this technique and its single-pump counterpart (1D VE) to probe the vibrational-electronic couplings between high frequency cyanide stretching vibrations (ν{sub CN}) and either a ligand-to-metal charge transfer transition ([Fe{sup III}(CN){sub 6}]{sup 3−} dissolved in formamide) or a metal-to-metal charge transfer (MMCT) transition ([(CN){sub 5}Fe{sup II}CNRu{sup III}(NH{sub 3}){sub 5}]{sup −} dissolved in formamide). The 2D VE spectra of both molecules reveal peaks resulting from coupled high- and low-frequency vibrational modes to the charge transfer transition. The time-evolving amplitudes and positions of the peaks in the 2D VE spectra report on coherent and incoherent vibrational energy transfer dynamics among the coupled vibrational modes and the charge transfer transition. The selectivity of 2D VE spectroscopy to vibronic processes is evidenced from the selective coupling of specific ν{sub CN} modes to the MMCT transition in the mixed valence complex. The lineshapes in 2D VE spectra report on the correlation of the frequency fluctuations between the coupled vibrational and electronic frequencies in the mixed valence complex which has a time scale of 1 ps. The details and results of this study confirm the versatility of 2D VE spectroscopy and its applicability to probe how vibrations modulate charge and energy transfer in a

  11. Pressure effects on the structure, kinetic, and thermodynamic properties of heat-induced aggregation of protein studied by FT-IR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Taniguchi, Y [Applied Chemistry Department, Ritsumeikan University, Kusatsu, Shiga 525-8577 (Japan); Okuno, A [Research Department 3, Central Research, Bridgestone Co. Kodaira, Tokyo 187-8531 (Japan); Kato, M, E-mail: taniguti@sk.ritsumei.ac.j [Pharmaceutical Sciences Department, Ritsumeikan University, Kusatsu, Shiga 525-8577 (Japan)

    2010-03-01

    Pressure can retrain the heat-induced aggregation and dissociate the heat-induced aggregates. We observed the aggregation-preventing pressure effect and the aggregates-dissociating pressure effect to characterize the heat-induced aggregation of equine serum albumin (ESA) by FT-IR spectroscopy. The results suggest the {alpha}-helical structure collapses at the beginning of heat-induced aggregation through the swollen structure, and then the rearrangement of structure to the intermolecular {beta}-sheet takes place through partially unfolded structure. We determined the activation volume for the heat-induced aggregation ({Delta}V'' = +93 ml/mol) and the partial molar volume difference between native state and heat-induced aggregates ({Delta}V=+32 ml/mol). This positive partial molar volume difference suggests that the heat-induced aggregates have larger internal voids than the native structure. Moreover, the positive volume change implies that the formation of the intermolecular {beta}-sheet is unfavorable under high pressure.

  12. Ultrafast Photochemistry of Copper(II) Monochlorocomplexes in Methanol and Acetonitrile by Broadband Deep-UV-to-Near-IR Femtosecond Transient Absorption Spectroscopy.

    Science.gov (United States)

    Mereshchenko, Andrey S; Olshin, Pavel K; Myasnikova, Olesya S; Panov, Maxim S; Kochemirovsky, Vladimir A; Skripkin, Mikhail Yu; Moroz, Pavel N; Zamkov, Mikhail; Tarnovsky, Alexander N

    2016-03-24

    Photochemistry of copper(II) monochlorocomplexes in methanol and acetonitrile solutions is studied by UV-pump/broadband deep-UV-to-near-IR probe femtosecond transient absorption spectroscopy. Upon 255 and 266 nm excitation, the complexes in acetonitrile and methanol, respectively, are promoted to the excited ligand-to-metal charge transfer (LMCT) state, which has a short (sub-250 fs) lifetime. From the LMCT state, the complexes decay via internal conversion to lower-lying ligand field (LF) d-d excited states or the vibrationally hot ground electronic state. A minor fraction of the excited complexes relaxes to the LF electronic excited states, which are relatively long-lived with lifetimes >1 ns. Also, in methanol solutions, about 3% of the LMCT-excited copper(II) monochlorocomplexes dissociate forming copper(I) solvatocomplexes and chlorine atoms, which then further react forming long-lived photoproducts. In acetonitrile, about 50% of the LMCT-excited copper(II) monochlorocomplexes dissociate forming radical and ionic products in a ratio of 3:2. Another minor process observed following excitation only in methanol solutions is the re-equilibration between several forms of the copper(II) ground-state complexes present in solutions. This re-equilibration occurs on a time scale from sub-nanoseconds to nanoseconds.

  13. Probing the role of chemical enhancers in facilitating drug release from patches: Mechanistic insights based on FT-IR spectroscopy, molecular modeling and thermal analysis.

    Science.gov (United States)

    Song, Wenting; Quan, Peng; Li, Shanshan; Liu, Chao; Lv, Siji; Zhao, Yongshan; Fang, Liang

    2016-04-10

    In patches, a drug must release from patches prior to its percutaneous absorption. Chemical enhancers have been used for several decades, but their roles in drug release from patches are poorly understood. In this work, the roles of chemical enhancers in bisoprolol tartrate (BSP-T) release from patches were probed in vitro and in vivo. More importantly, an innovative mechanism insight of chemical enhancers in drug release process was provided at molecular level. FT-IR spectroscopy and molecular modeling were employed to investigate the influence of chemical enhancers on drug-adhesive interaction. The results showed chemical enhancers like Span 80, which had a strong ability forming hydrogen bonds, could decrease drug-adhesive interaction leading to the release of drug from adhesive of patches. Thermal analysis was conducted to research the influence of chemical enhancers on the thermodynamic properties of patch system. It showed that chemical enhancers promoted the formation of free volume of adhesive, which facilitated drug release process. By contrast, the influence on the thermodynamic properties of BSP-T was less effective in influencing BSP-T release process. In conclusion, chemical enhancers played an important role in facilitating BSP-T release from the adhesive DURO-TAK® 87-2287 of patches by decreasing drug-adhesive interaction and promoting the formation of free volume of adhesive. This work may be an important step in understanding the important roles of chemical enhancers in drug release process.

  14. Using attenuated total reflection Fourier transform infrared spectroscopy (ATR FT-IR) to study the molecular conformation of parchment artifacts in different macroscopic states.

    Science.gov (United States)

    Gonzalez, Lee; Wade, Matthew; Bell, Nancy; Thomas, Kate; Wess, Tim

    2013-02-01

    Maintaining appropriate temperatures and relative humidity is considered essential to extending the useful life of parchment artifacts. Although the relationship between environmental factors and changes to the physical state of artifacts is reasonably understood, an improved understanding of the relationship between the molecular conformation and changes to the macroscopic condition of parchment is needed to optimize environmental conditions. Using Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR FT-IR) analysis, the conformation of the molecular structure in selected parchment samples with specific macroscopic conditions, typically discoloration and planar deformations (e.g., cockling and tearing), have been made. The results of this investigation showed that the Fourier transform infrared signal differs for parchment samples exhibiting different macroscopic conditions. In areas exhibiting planar deformation, a change in the Fourier Transform Infrared signal was observed that indicates unfolding of the molecular conformation. In comparison, the discolored samples showed a change in molecular conformation that indicates a chemical change within the collagen molecular structure. This paper discusses the possible causal associations and implications of these findings for the conservation and preservation of parchment artifacts.

  15. ESIPT and photodissociation of 3-hydroxychromone in solution: photoinduced processes studied by static and time-resolved UV/Vis, fluorescence, and IR spectroscopy.

    Science.gov (United States)

    Chevalier, Katharina; Grün, Anneken; Stamm, Anke; Schmitt, Yvonne; Gerhards, Markus; Diller, Rolf

    2013-11-01

    The spectral properties of fluorescence sensors such as 3-hydroxychromone (3-HC) and its derivatives are sensitive to interaction with the surrounding medium as well as to substitution. 3-HC is a prototype system for other derivatives because it is the basic unit of all flavonoides undergoing ESIPT and is not perturbed by a substituent. In this study, the elementary processes and intermediate states in the photocycle of 3-HC as well as its anion were identified and characterized by the use of static and femtosecond time-resolved spectroscopy in different solvents (methylcyclohexane, acetonitrile, ethanol, and water at different pH). Electronic absorption and fluorescence spectra and lifetimes of the intermediate states were obtained for the normal, tautomer and anionic excited state, while mid-IR vibrational spectra yielded structural information on ground and excited states of 3-HC. A high sensitivity on hydrogen-bonding perturbations was observed, leading to photoinduced anion formation in water, while in organic solvents, different processes are suggested, including slow picosecond ESIPT and contribution of the trans-structure excited state or a different stable solvation state with different direction of OH. The formation of the latter could be favored by the lack of a substituent increasing contact points for specific solute-solvent interactions at the hydroxyl group compared to substituted derivatives. The effect of substituents has to be considered for the design of future fluorescence sensors based on 3-HC. PMID:24083478

  16. NH3 adsorption and decomposition on Ir(110): A combined temperature programmed desorption and high resolution fast x-ray photoelectron spectroscopy study

    International Nuclear Information System (INIS)

    The adsorption and decomposition of NH3 on Ir(110) has been studied in the temperature range from 80 K to 700 K. By using high-energy resolution x-ray photoelectron spectroscopy it is possible to distinguish chemically different surface species. At low temperature a NH3 multilayer, which desorbs at ∼110 K, was observed. The second layer of NH3 molecules desorbs around 140 K, in a separate desorption peak. Chemisorbed NH3 desorbs in steps from the surface and several desorption peaks are observed between 200 and 400 K. A part of the NH3ad decomposes into NHad between 225 and 300 K. NHad decomposes into Nad between 400 K and 500 K and the hydrogen released in this process immediately desorbs. N2 desorption takes place between 500 and 700 K via Nad combination. The steady state decomposition reaction of NH3 starts at 500 K. The maximum reaction rate is observed between 540 K and 610 K. A model is presented to explain the occurrence of a maximum in the reaction rate. Hydrogenation of Nad below 400 K results in NHad. No NH2ad or NH3ad/NH3 were observed. The hydrogenation of NHad only takes place above 400 K. On the basis of the experimental findings an energy scheme is presented to account for the observations

  17. Lectures on 2D gravity and 2D string theory

    International Nuclear Information System (INIS)

    This report the following topics: loops and states in conformal field theory; brief review of the Liouville theory; 2D Euclidean quantum gravity I: path integral approach; 2D Euclidean quantum gravity II: canonical approach; states in 2D string theory; matrix model technology I: method of orthogonal polynomials; matrix model technology II: loops on the lattice; matrix model technology III: free fermions from the lattice; loops and states in matrix model quantum gravity; loops and states in the C=1 matrix model; 6V model fermi sea dynamics and collective field theory; and string scattering in two spacetime dimensions

  18. 2D-hahmoanimaation toteuttamistekniikat

    OpenAIRE

    Smolander, Aku

    2009-01-01

    Opinnäytetyössä tutkitaan erilaisia 2D-hahmoanimaation toteuttamistekniikoita. Aluksi luodaan yleiskatsaus animoinnin historiaan ja tekniikoihin piirtämisestä mallintamiseen. Alkukatsauksen jälkeen tutkitaan 2D-hahmon suunnittelua ja liikkeitä koskevia sääntöjä. Hahmoanimaation liikkeissä huomionarvoisia asioita ovat muun muassa ajastus, liioittelu, ennakointi ja painovoima. Seuraavaksi perehdytään itse 2D-hahmoanimaation toteuttamistekniikoihin. Tavoitteena on selvittää, tutkia ja vertailla ...

  19. Determination of organic additives in mortars by near-IR spectroscopy. A novel approach to designing a sample set with high-variability components.

    Science.gov (United States)

    Blanco, Marcelo; Peguero, Anna

    2007-02-01

    Industrial mortars consist primarily of a mixture of cement and an aggregate plus a small amount of additives that are used to modify specific properties. Using too high or too low additive rates usually results in the loss of desirable properties in the end product. This entails carefully controlling the amounts of additives added to mortar in order to ensure correct dosing and/or adequate homogeneity in the final mixture. Near-IR (NIR) spectroscopy has proved effective for this purpose as it requires no sample pretreatment and affords expeditious analyses. The purpose of this work was to determine two organic additives (viz. Ad1 and Ad2) in mortars by using partial least squares regression multivariate calibration models constructed from NIR spectroscopic data. The additives are used to expedite setting and increase cohesion between particles in the mortar. In order to ensure that the sample set contained natural variability in the samples, we used a methodology based on experimental design to construct a representative set of samples. This novel design is based on a hexagonal antiprism that encompasses the concentration ranges spanned by the analytes and the variability inherent in each additive. The D-optimality criterion was used to obtain various combinations between Ad1 and Ad2 additive classes. The partial least squares calibration models thus constructed for each additive provided accurate predictions: the intercept and the slope of the plots of predicted values versus reference values for each additive were close to 0 and 1, respectively, and their confidence ranges included the respective value. The ensuing analytical methods were validated by using an external sample set.

  20. FT-IR, FT-Raman, UV-Visible, and NMR spectroscopy and vibrational properties of the labdane-type diterpene 13-epi-sclareol

    Science.gov (United States)

    Chain, Fernando E.; Leyton, Patricio; Paipa, Carolina; Fortuna, Mario; Brandán, Silvia A.

    2015-03-01

    In this work, FT-IR, FT-Raman, UV-Visible and NMR spectroscopies and density functional theory (DFT) calculations were employed to study the structural and vibrational properties of the labdane-type diterpene 13-epi-sclareol using the hybrid B3LYP method together with the 6-31G∗ basis set. Three stable structures with minimum energy found on the potential energy curves (PES) were optimized, and the corresponding molecular electrostatic potentials, atomic charges, bond orders, stabilization energies and topological properties were computed at the same approximation level. The complete assignment of the bands observed in the vibrational spectrum of 13-epi-sclareol was performed taking into account the internal symmetry coordinates for the three structures using the scaled quantum mechanical force field (SQMFF) methodology at the same level of theory. In addition, the force constants were calculated and compared with those reported in the literature for similar compounds. The predicted vibrational spectrum and the calculated 1H NMR and 13C NMR chemical shifts are in good agreement with the corresponding experimental results. The theoretical UV-Vis spectra for the most stable structure of 13-epi-sclareol demonstrate a better correlation with the corresponding experimental spectrum. The study of the three conformers by means of the theory of atoms in molecules (AIM) revealed different H bond interactions and a strong dependence of the interactions on the distance between the involved atoms. Furthermore, the natural bond orbital (NBO) calculations showed the characteristics of the electronic delocalization for the two six-membered rings with chair conformations.

  1. Characterization studies and cytotoxicity assays of Pt(II) and Pd(II) dithiocarbamate complexes by means of FT-IR, NMR spectroscopy and mass spectrometry.

    Science.gov (United States)

    Alverdi, V; Giovagnini, L; Marzano, C; Seraglia, R; Bettio, F; Sitran, S; Graziani, R; Fregona, D

    2004-06-01

    The precursors [M(ESDTM)Cl(2)] (M=Pt(II), Pd(II); ESDTM=EtO(2)CCH(2)(CH(3))NCS(2)Me, S-methyl(ethylsarcosinedithiocarbamate)) were synthesized as previously reported [J. Inorg. Biochem. 83 (2001) 31] and used to obtain [M(ESDT)Cl](n) (ESDT=ethylsarcosinedithiocarbamate anion) species. The complexes formed through reaction between [M(ESDT)Cl](n) and the two chiral amino-alcohols synephryne (Syn) and norphenylephrine (Nor) have been synthesized, with the ultimate goal of preparing mixed dithiocarbamate/amino metal complexes of the type [M(ESDT)(Am)Cl] (Am=Syn, Nor). These compounds have been isolated, purified and characterized by means of FT-IR, mono- and bidimensional NMR spectroscopy and mass spectrometry ESI/MS (electronspray mass spectra). The experimental data suggest that in all cases coordination of the dithiocarbamate ligand (ESDT) takes a place through the two sulfur atoms, the -NCSS moiety acting as a symmetrical bidentate chelating group, in a square-planar geometry around the M(II) ion, while the other two coordination positions are occupied by the chlorine atom and the amino-alcohol ligand, respectively. In particular, synephrine and norphenylephrine appear to be bound to the metal atom through the amino nitrogen atom by means of a dative bond. Finally, the biological activity of the new complexes has been studied by MTT (tetrazolio salt reduction) test and by detecting the inhibition of DNA synthesis and of clonal growth in various cancer cell lines. All Pd(II) derivatives showed a noticeable activity very close to that of cisplatin, used as reference drug. Moreover, they showed significantly reduced cross-resistance to cisplatin in a pair of cell lines (2008/C13*) with known acquired cisplatin resistance mechanisms. PMID:15149823

  2. FT-IR光谱在电离辐射作用于微生物研究中的应用%Application of FT-IR Spectroscopy in Study of Biological Effects on Microorganisms Induced by Ionizing Radiation

    Institute of Scientific and Technical Information of China (English)

    刘京华; 黄青

    2012-01-01

    傅里叶变换红外光谱(Fourier transform infrared spectroscopy,FT-IR)是一种很有用的生物分析检测技术,通过FT-IR光谱技术可以得到有关蛋白质、脂类、核酸和多糖等微生物和细胞各类组成成分的信息.基于同步辐射光源的显微FT-IR光谱具有更高的空间分辨率和更快的测量速度,因而在生物学研究中具有进行快速、实时、动态和无损检测等优势.本文介绍了FT-IR光谱技术在微生物及电离辐射作用于微生物引起的生物学效应研究中的应用,并对该领域未来研究的发展趋势进行了展望.%Fourier transform infrared (FT-IR) spectroscopy is a useful and powerful technique that can provide rich information on proteins,lipids,nucleic acids and carbohydrates in biological systems. Especially,the high-resolution synchrotron Fourier-transform infrared (SR-FTIR) microspectroscopy and imaging technique can be employed as an excellent tool for convenient,fast,non-invasive,and real-time monitoring of varied complicated processes occuring in a biological system. In this review,the authors discuss the recent progress on the application of FT-IR spectroscopy in the study of biological effects on microorganisms induced by ionizing radiation,and also give an outlook for the future FT-IR spectroscopy research in this field.

  3. Spectroscopy

    DEFF Research Database (Denmark)

    Berg, Rolf W.

    This introductory booklet covers the basics of molecular spectroscopy, infrared and Raman methods, instrumental considerations, symmetry analysis of molecules, group theory and selection rules, as well as assignments of fundamental vibrational modes in molecules.......This introductory booklet covers the basics of molecular spectroscopy, infrared and Raman methods, instrumental considerations, symmetry analysis of molecules, group theory and selection rules, as well as assignments of fundamental vibrational modes in molecules....

  4. Functional characterization of a first avian cytochrome P450 of the CYP2D subfamily (CYP2D49.

    Directory of Open Access Journals (Sweden)

    Hua Cai

    Full Text Available The CYP2D family members are instrumental in the metabolism of 20-25% of commonly prescribed drugs. Although many CYP2D isoforms have been well characterized in other animal models, research concerning the chicken CYP2Ds is limited. In this study, a cDNA encoding a novel CYP2D enzyme (CYP2D49 was cloned from the chicken liver for the first time. The CYP2D49 cDNA contained an open reading frame of 502 amino acids that shared 52%-57% identities with other CYP2Ds. The gene structure and neighboring genes of CYP2D49 are conserved and similar to those of human CYP2D6. Additionally, similar to human CYP2D6, CYP2D49 is un-inducible in the liver and expressed predominantly in the liver, kidney and small intestine, with detectable levels in several other tissues. Metabolic assays of the CYP2D49 protein heterologously expressed in E. coli and Hela cells indicated that CYP2D49 metabolized the human CYP2D6 substrate, bufuralol, but not debrisoquine. Moreover, quinidine, a potent inhibitor of human CYP2D6, only inhibited the bufuralol 1'-hydroxylation activity of CYP2D49 to a negligible degree. All these results indicated that CYP2D49 had functional characteristics similar to those of human CYP2D6 but measurably differed in the debrisoquine 4'-hydroxylation and quinidine inhibitory profile. Further structure-function investigations that employed site-directed mutagenesis and circular dichroism spectroscopy identified the importance of Val-126, Glu-222, Asp-306, Phe-486 and Phe-488 in keeping the enzymatic activity of CYP2D49 toward bufuralol as well as the importance of Asp-306, Phe-486 and Phe-488 in maintaining the conformation of CYP2D49 protein. The current study is only the first step in characterizing the metabolic mechanism of CYP2D49; further studies are still required.

  5. Excitation of 2D plasmons in Cs/W(110)

    CERN Document Server

    Benemanskaya, G V; Frank-Kamenetskaya, G E

    2001-01-01

    One studied the evolution of surface photoemission spectra for Cs/W(110) system at metastable Cs coatings exceeding monolayer. One showed possibility to observe 2D plasmons by means of threshold photoemission spectroscopy. One detected three photoemission peaks characterized by complicated behavior depending on Cd adsorption dose. The nature of peaks may be related to plasmon photoinduced excitation in quasi-2D Cs clusters, surface Cs plasmon and interface Cs-W plasmon

  6. Speciation of organic matter in sandy soil size fractions as revealed by analytical pyrolysis (Py-GC/MS) and FT-IR spectroscopy

    Science.gov (United States)

    Jiménez-Morillo, Nicasio T.; González-Vila, Francisco J.; Jordán, Antonio; Zavala, Lorena M.; de la Rosa, José M.; González-Pérez, José A.

    2015-04-01

    This research deals with the assessment of organic matter structural differences in soil physical fractions before and after lipid extractions. Soil samples were collected in sandy soils, Arenosols (WRB 2006) from the Doñana National Park (SW Spain) under different vegetation cover: cork oak (Quercus suber, QS), eagle fern (Pteridium aquilinum, PA), pine (Pinus pinea, PP) and rockrose (Halimium halimifolium, HH). Two size fractions; coarse (C: 1-2 mm) and fine (F: 0.05-0.25 mm) were studied from each soil. . In addition, the two fractions from each soil were exhaustively Soxhlet extracted with a Dichlorometane-Methanol (3:1) mixture to obtain the lipid-free fractions (LF) from each size fraction (LFC and LFF). The composition of the organic matter at a molecular level in the different soil fractions was approached by analytical pyrolysis (Py-GC/MS) and FT-IR spectroscopy. These techniques are complementary and have been found suitable for the structural characterization of complex organic matrices (Moldoveanu, 1998; Piccolo and Stevenson, 1982); whereas Py-GC/MS provides detailed structural information of individual compounds present and a finger-printing of soil organic matter, FT-IR is informative about major functional groups present. The advantages of these techniques are well known: no need for pretreatment are fast to perform, highly reproducible and only small amount of samples are needed. Soil size fractions show contrasting differences in organic matter content (C 4-7 % and F > 40 %) and conspicuous differences were found in the pyrolysis products released by the fractions studied. The main families of pyrolysis compounds have well defined macromolecular precursors, such as lignin, polypeptides, polysaccharides and lipids (González-Vila et al., 2001). The C fractions yield higher relative abundance of lignin and polysaccharide derived pyrolysis compounds. Regarding the differences in the soil organic matter as affected by the different vegetation covers

  7. Accretion Disks Phase Transitions 2-D or not 2-D?

    CERN Document Server

    Abramowicz, M A; Igumenshchev, I V; Abramowicz, Marek Artur; Bjornsson, Gunnlaugur; Igumenshchev, Igor V.

    2000-01-01

    We argue that the proper way to treat thin-thick accretion-disk transitions should take into account the 2-D nature of the problem. We illustrate the physical inconsistency of the 1-D vertically integrated approach by discussing a particular example of the convective transport of energy.

  8. The metastable HCl · 6H2O phase – IR spectroscopy, phase transitions and kinetic/thermodynamic properties in the range 170–205 K

    Directory of Open Access Journals (Sweden)

    S. Chiesa

    2013-07-01

    Full Text Available In this laboratory study, 1 to 2 μm thick polycrystalline ice films have been grown under stirred flow reactor (SFR conditions and subsequently doped with metered amounts of HCl under static conditions. A multidiagnostic approach including FTIR absorption spectroscopy in transmission, residual gas mass spectrometry (MS and total pressure measurement was employed. Depending on the growth protocol controlling both temperature and partial pressure of HCl (PHCl, either amorphous HCl/H2O or crystalline HCl hexahydrate (HCl · 6H2O have been obtained. After controlled doping with HCl and evaporation of excess H2O from the ice film, transmission FTIR of pure HCl · 6H2O films and use of calibrated residual gas MS enabled the measurement of differential (peak IR cross sections at several mid-IR frequencies (σ = (6.5 ± 1.9 × 10-19 cm2 molec-1 at 1635 cm-1 as an example. Two types of kinetic experiments on pure HCl · 6H2O have been performed under SFR conditions: (a evaporation of HCl · 6H2O under H2O-poor conditions over a narrow T range, and (b observation of the phase transition from crystalline HCl · 6H2O to amorphous HCl/H2O under H2O-rich conditions at increasing T. The temperature dependence of the zero-order evaporation flux of HCl in pure HCl · 6H2O monitored at 3426 cm-1 led to log(Jev molec cm-2s-1= (36.34 ± 3.20 - (80 810 ± 5800/2.303RT with R=8.312 JK−1 mol-1. HCl · 6H2O has a significant intrinsic kinetic barrier to HCl evaporation of 15.1 kJ mol-1 in excess of the HCl sublimation enthalpy of 65.8 kJ mol-1 at 200 K but is kinetically unstable (metastable at typical UT/LS conditions of HCl partial pressure (P(HCl and temperature. Water-rich HCl · 6H2O undergoes a facile phase transition from crystalline to the amorphous/ supercooled/disordered state easily observable at T≥ 195 K under both static and SFR conditions. This corresponds to low P(HCl in the neighborhood of 10-7 Torr that also prevails at the Upper Troposphere

  9. Multi-pollutants sensors based on near-IR telecom lasers and mid-IR difference frequency generation: development and applications; Instruments de mesure multi-polluants par spectroscopie infrarouge bases sur des lasers fibres et par generation de difference de frequences: developpement et applications

    Energy Technology Data Exchange (ETDEWEB)

    Cousin, J

    2006-12-15

    At present the detection of VOC and other anthropic trace pollutants is an important challenge in the measurement of air quality. Infrared spectroscopy, allowing spectral regions rich in molecular absorption to be probed, is a suitable technique for in-situ monitoring of the air pollution. Thus the aim of this work was to develop instruments capable of detecting multiple pollutants for in-situ monitoring by IR spectroscopy. A first project benefited from the availability of the telecommunications lasers emitting in near-IR. This instrument was based on an external cavity diode laser (1500 - 1640 nm) in conjunction with a multipass cell (100 m). The detection sensitivity was optimised by employing a balanced detection and a sweep integration procedure. The instrument developed is deployable for in-situ measurements with a sensitivity of < 10{sup -8} cm{sup -1} Hz{sup -1/2} and allowed the quantification of chemical species such as CO{sub 2}, CO, C{sub 2}H{sub 2}, CH{sub 4} and the determination of the isotopic ratio {sup 13}CO{sub 2}/{sup 12}CO{sub 2} in combustion environment The second project consisted in mixing two near-IR fiber lasers in a non-linear crystal (PPLN) in order to produce a laser radiation by difference frequency generation in the middle-IR (3.15 - 3.43 {mu}m), where the absorption bands of the molecules are the most intense. The first studies with this source were carried out on detection of ethylene (C{sub 2}H{sub 4}) and benzene (C{sub 6}H{sub 6}). Developments, characterizations and applications of these instruments in the near and middle IR are detailed and the advantages of the 2 spectral ranges is highlighted. (author)

  10. SES2D user's manual

    International Nuclear Information System (INIS)

    SES2D is an interactive graphics code designed to generate plots of equation of state data from the Los Alamos National Laboratory Group T-4 computer libraries. This manual discusses the capabilities of the code. It describes the prompts and commands and illustrates their use with a sample run

  11. Computational 2D Materials Database

    DEFF Research Database (Denmark)

    Rasmussen, Filip Anselm; Thygesen, Kristian Sommer

    2015-01-01

    , and comparison is made with different density functional theory descriptions. Pitfalls related to the convergence of GW calculations for two-dimensional (2D) materials are discussed together with possible solutions. The monolayer band edge positions relative to vacuum are used to estimate the band alignment...

  12. Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (ATR FT-IR) Mapping Coupled with Multivariate Curve Resolution (MCR) for Studying the Miscibility of Chlorobutyl Rubber/Polyamide-12 Blends.

    Science.gov (United States)

    Tang, Yongjiao; Jing, Nan; Zhang, Pudun

    2015-11-01

    A series of chlorobutyl rubber/polyamide-12 (CIIR/PA-12) blends compatibilized by different amounts of maleic anhydride (MAH) grafted polypropylene (PP-g-MAH) were investigated by attenuated total reflection Fourier transform infrared spectroscopy (ATR FT-IR) mapping. Multivariate curve resolution (MCR) was used to process the FT-IR images. Both the spectra of pure components in the blends and their concentration distributions in a micro-region were acquired. Our results demonstrated that the blend with 15 parts per hundred rubber PP-g-MAH showed the best miscibility. An amide interphase and an imide interphase were inferred by analyzing the spectra of MCR component 3 of the blends with and without PP-g-MAH, respectively. Correspondingly, two different compatibilizing mechanisms were proposed for these blends. PMID:26647055

  13. Aero Fighter - 2D Gaming

    CERN Document Server

    Ahmed, Zeeshan

    2010-01-01

    Designing and developing quality based computer game is always a challenging task for developers. In this paper I briefly discuss aero fighting war game based on simple 2D gaming concepts and developed in C & C++ programming languages, using old bitmapping concepts. Going into the details of the game development, I discuss the designed strategies, flow of game and implemented prototype version of game, especially for beginners of game programming.

  14. Electronic and chemical structure of an organic light emitter embedded in an inorganic wide-bandgap semiconductor: Photoelectron spectroscopy of layered and composite structures of Ir(BPA) and ZnSe

    Energy Technology Data Exchange (ETDEWEB)

    Dimamay, Mariel [Institute of Materials Science, Darmstadt University of Technology, Alarich-Weiss-Strasse 2, D-64287 Darmstadt (Germany); Laboratoire de Chimie des Polymères Organiques, CNRS, Université de Bordeaux, UMR 5629-16 Avenue Pey-Berland, 33607 Pessac (France); Mayer, Thomas; Jaegermann, Wolfram [Institute of Materials Science, Darmstadt University of Technology, Alarich-Weiss-Strasse 2, D-64287 Darmstadt (Germany); Hadziioannou, Georges [Laboratoire de Chimie des Polymères Organiques, CNRS, Université de Bordeaux, UMR 5629-16 Avenue Pey-Berland, 33607 Pessac (France)

    2015-05-07

    Luminescent organic phases embedded in conductive inorganic matrices are proposed for hybrid organic-inorganic light-emitting diodes. In this configuration, the organic dye acts as the radiative recombination site for charge carriers injected into the inorganic matrix. Our investigation is aimed at finding a material combination where the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of the organic dye are situated in between the valence and conduction bands of the inorganic matrix in order to promote electron and hole transfer from the matrix to the dye. Bilayer and composite thin films of zinc selenide (ZnSe) and a red iridium complex (Ir(BPA)) organic light emitter were prepared in situ via UHV thermal evaporation technique. The electronic and atomic structures were studied applying X-ray and ultraviolet photoelectron spectroscopies. The measured energy band alignments for the ZnSe/Ir(BPA) bilayer and ZnSe+Ir(BPA) composite reveal that the HOMO and LUMO of the organic dye are positioned in the ZnSe bandgap. For the initial steps of ZnSe deposition on a dye film to form Ir(BPA)/ZnSe bilayers, zinc atoms intercalate into the dye film leaving behind an excess of selenium at the interface that partly reacts with dye molecules. Photoelectron spectroscopy of the composites shows the same species suggesting a similar mechanism. This mechanism leads to composite films with increased content of amorphous phases in the inorganic matrix, thereby affecting its conductivity, as well as to the presence of nonradiative recombination sites provided by the intercalated Zn atoms.

  15. Electronic and chemical structure of an organic light emitter embedded in an inorganic wide-bandgap semiconductor: Photoelectron spectroscopy of layered and composite structures of Ir(BPA) and ZnSe

    Science.gov (United States)

    Dimamay, Mariel; Mayer, Thomas; Hadziioannou, Georges; Jaegermann, Wolfram

    2015-05-01

    Luminescent organic phases embedded in conductive inorganic matrices are proposed for hybrid organic-inorganic light-emitting diodes. In this configuration, the organic dye acts as the radiative recombination site for charge carriers injected into the inorganic matrix. Our investigation is aimed at finding a material combination where the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of the organic dye are situated in between the valence and conduction bands of the inorganic matrix in order to promote electron and hole transfer from the matrix to the dye. Bilayer and composite thin films of zinc selenide (ZnSe) and a red iridium complex (Ir(BPA)) organic light emitter were prepared in situ via UHV thermal evaporation technique. The electronic and atomic structures were studied applying X-ray and ultraviolet photoelectron spectroscopies. The measured energy band alignments for the ZnSe/Ir(BPA) bilayer and ZnSe+Ir(BPA) composite reveal that the HOMO and LUMO of the organic dye are positioned in the ZnSe bandgap. For the initial steps of ZnSe deposition on a dye film to form Ir(BPA)/ZnSe bilayers, zinc atoms intercalate into the dye film leaving behind an excess of selenium at the interface that partly reacts with dye molecules. Photoelectron spectroscopy of the composites shows the same species suggesting a similar mechanism. This mechanism leads to composite films with increased content of amorphous phases in the inorganic matrix, thereby affecting its conductivity, as well as to the presence of nonradiative recombination sites provided by the intercalated Zn atoms.

  16. Metrology for graphene and 2D materials

    Science.gov (United States)

    Pollard, Andrew J.

    2016-09-01

    The application of graphene, a one atom-thick honeycomb lattice of carbon atoms with superlative properties, such as electrical conductivity, thermal conductivity and strength, has already shown that it can be used to benefit metrology itself as a new quantum standard for resistance. However, there are many application areas where graphene and other 2D materials, such as molybdenum disulphide (MoS2) and hexagonal boron nitride (h-BN), may be disruptive, areas such as flexible electronics, nanocomposites, sensing and energy storage. Applying metrology to the area of graphene is now critical to enable the new, emerging global graphene commercial world and bridge the gap between academia and industry. Measurement capabilities and expertise in a wide range of scientific areas are required to address this challenge. The combined and complementary approach of varied characterisation methods for structural, chemical, electrical and other properties, will allow the real-world issues of commercialising graphene and other 2D materials to be addressed. Here, examples of metrology challenges that have been overcome through a multi-technique or new approach are discussed. Firstly, the structural characterisation of defects in both graphene and MoS2 via Raman spectroscopy is described, and how nanoscale mapping of vacancy defects in graphene is also possible using tip-enhanced Raman spectroscopy (TERS). Furthermore, the chemical characterisation and removal of polymer residue on chemical vapour deposition (CVD) grown graphene via secondary ion mass spectrometry (SIMS) is detailed, as well as the chemical characterisation of iron films used to grow large domain single-layer h-BN through CVD growth, revealing how contamination of the substrate itself plays a role in the resulting h-BN layer. In addition, the role of international standardisation in this area is described, outlining the current work ongoing in both the International Organization of Standardization (ISO) and the

  17. An X-ray photoelectron spectroscopy study of the products of the interaction of gaseous IrF6 with fine UO2F2

    OpenAIRE

    Prusakov Vladimir N.; Teterin Yury A.; Trotsenko Nikolai M.; Maslakov Konstantin I.; Teterin Anton Yu.; Ivanov Kirill E.; Bochagin Filipp S.; Utrobin Dmitry V.

    2007-01-01

    Nuclear fuel reprocessing by fluorination, a dry method of regeneration of spent nuclear fuel, uses UO2F2 for the separation of plutonium from gaseous mixtures. Since plutonium requires special treatment, IrF6 was used as a thermodynamic model of PuF6. The model reaction of the interaction of gaseous IrF6 with fine UO2F2 in the sorption column revealed a change of color of the sorption column contents from pale-yellow to gray and black, indicating the formation of products of such an interact...

  18. Using ATR-FT/IR molecular spectroscopy to detect effects of blend DDGS inclusion level on the molecular structure spectral and metabolic characteristics of the proteins in hulless barley

    Science.gov (United States)

    Zhang, Xuewei; Yu, Peiqiang

    2012-09-01

    The objectives of this study were to investigate the effects of inclusion of a bioethanol co-product of blend DDGS (wheat:corn = 70%:30%) on protein molecular structure spectral and metabolic characteristics in hulless barley-based feed using ATR-FT/IR molecular spectroscopy. Hulless barley grain with the blend DDGS were mixed in the five ratios. The results showed that when blend DDGS was included at an increased ratio, predicted truly absorbed protein supply was highly and linearly increased (P products for dairy and beef cattle.

  19. 2D-animaatiotuotannon optimointi

    OpenAIRE

    Saturo, Reetta

    2015-01-01

    Tämän opinnäytetyön tavoitteena on tutkia 2D-animaatiotuotannon optimoinnin mahdollisuuksia tiukan tuotantoaikataulun vaatimuksissa. Tutkielmassa tarkastellaan kahta asiakasprojektia, jotka on toteutettu pienellä tuotantotiimillä. Työkaluna animaatioissa on käytetty pääosin Adoben After Effects -ohjelmistoa. Tutkielman alussa esitellään animaatiotuotannot, joiden tuloksena syntyi kaksi lyhyttä mainoselokuvaa. Sen jälkeen käydään läpi animaatioelokuvan tuotantoprosessia vaiheittain ja tark...

  20. Head First 2D Geometry

    CERN Document Server

    Fallow), Stray

    2009-01-01

    Having trouble with geometry? Do Pi, The Pythagorean Theorem, and angle calculations just make your head spin? Relax. With Head First 2D Geometry, you'll master everything from triangles, quads and polygons to the time-saving secrets of similar and congruent angles -- and it'll be quick, painless, and fun. Through entertaining stories and practical examples from the world around you, this book takes you beyond boring problems. You'll actually use what you learn to make real-life decisions, like using angles and parallel lines to crack a mysterious CSI case. Put geometry to work for you, and

  1. IR mass-resolved spectroscopy of complexes without chromophore: cyclohexanol·(H2O)n, n = 1-3 and cyclohexanol dimer.

    Science.gov (United States)

    León, Iker; Montero, Raúl; Longarte, Asier; Fernández, José A

    2013-11-01

    Mass-resolved IR spectra of cyclohexanol-water clusters and cyclohexanol dimer in supersonic expansions are presented for the first time. A combination of ns and fs IR lasers made possible recording such spectra without inclusion of a chromophore or a messenger atom. Furthermore, employment of the recently developed IR(3) technique [I. León, R. Montero, F. Castaño, A. Longarte, and J. A. Fernández, J. Phys. Chem. A 116, 6798 (2012)] allowed us to discriminate between the contribution of different species to the IR spectrum. Comparison of the experimental spectra with the predictions at the M06-2X/6-311++G(d,p) calculation level confirmed the assignment of the spectrum of cyclohexanol·(H2O)1 to a structure in which water is accepting a proton from cyclohexanol's OH group, and those of cyclohexanol·(H2O)(2,3) to structures with cyclic hydrogen bond networks. A comparative analysis of the results obtained with those reported on other aromatic alcohols is also offered.

  2. IR mass-resolved spectroscopy of complexes without chromophore: Cyclohexanol·(H{sub 2}O){sub n}, n = 1–3 and cyclohexanol dimer

    Energy Technology Data Exchange (ETDEWEB)

    León, Iker; Montero, Raúl; Longarte, Asier; Fernández, José A., E-mail: josea.fernandez@ehu.es [Department of Physical Chemistry, Faculty of Science and Technology, University of the Basque Country-UPV/EHU, Barrio Sarriena s/n, Leioa 48940 (Spain)

    2013-11-07

    Mass-resolved IR spectra of cyclohexanol-water clusters and cyclohexanol dimer in supersonic expansions are presented for the first time. A combination of ns and fs IR lasers made possible recording such spectra without inclusion of a chromophore or a messenger atom. Furthermore, employment of the recently developed IR{sup 3} technique [I. León, R. Montero, F. Castaño, A. Longarte, and J. A. Fernández, J. Phys. Chem. A 116, 6798 (2012)] allowed us to discriminate between the contribution of different species to the IR spectrum. Comparison of the experimental spectra with the predictions at the M06-2X/6-311++G(d,p) calculation level confirmed the assignment of the spectrum of cyclohexanol·(H{sub 2}O){sub 1} to a structure in which water is accepting a proton from cyclohexanol's OH group, and those of cyclohexanol·(H{sub 2}O){sub 2,3} to structures with cyclic hydrogen bond networks. A comparative analysis of the results obtained with those reported on other aromatic alcohols is also offered.

  3. UV-vis, IR and 1H NMR spectroscopic studies and characterization of ionic-pair crystal violet-oxytetracycline

    Science.gov (United States)

    Orellana, Sandra; Soto, César; Toral, M. Inés

    2010-01-01

    The present study shows the formation and characterization of the ionic-pair between the antibiotic oxytetracycline and the dye crystal violet in ammonia solution pH 9.0 ± 0.2 extracted into chloroform. The characterization was demonstrated using UV-vis spectrophotometry, 1H NMR, measurement of relaxation times T1 and IR spectroscopy, using a comparison between the signals of individual pure compounds with the signals with the mixture CV-OTC in different alkaline media. The formation of ionic-pair was also corroborated by new signals and chemical shifts. (2D) NMR spectroscopy experiments show that the interaction is electrostatic.

  4. Effect of pH on the Nitrite Hydrogenation Mechanism over Pd/Al2O3 and Pt/Al2O3: Details Obtained with ATR-IR Spectroscopy

    DEFF Research Database (Denmark)

    Ebbesen, Sune Dalgaard; Mojet, Barbara L.; Lefferts, Leon

    2011-01-01

    It is well-known that activity and selectivity to N2 during nitrite hydrogenation over noble metal catalysts in water depend on the pH of the solution, but mechanistic understanding is lacking. Attenuated total reflection infrared (ATR-IR) spectroscopy is an ideal tool to perform detailed studies...... on catalytic surfaces in water. In this paper, the influence of pH was studied on adsorption and subsequent hydrogenation of nitrite in water between pH 5 and 9 over Pd/Al2O3 and Pt/Al2O3, using ATR-IR spectroscopy. On both catalysts, pH clearly influenced the surface coverage and reaction rates...... of intermediates. For Pt/Al2O3, lowering the pH induced the increasing surface coverage of key reaction intermediates like NOsteps1620cm−1 and “HNO”(ads)1540cm−1, as well as increased hydrogenation rates, explaining the higher TOF at lower pH as reported in the literature. For Pd/Al2O3, the effect of pH...

  5. IRS and ESR characterizations of nanocomposite thin films derived from alkanethiolates and gold nanoparticles[Infrared Reflectance Spectroscopy, Electron Spin Resonance

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, W.X.; Leibowitz, F.L.; Maye, M.M.; Gilbert, D.C.; Doetschman, D.C.; Zhong, C.J.

    2000-07-01

    A key to the ultimate technological applications of core-shell nanoparticle materials is the understanding of the structure-property correlation. This work focuses on the characterizations of te structural properties for composite thin films derived from gold nanoparticles and thiolates using infrared reflectance spectroscopic (IRS) and electron spin resonance (ESR) techniques. IRS provides information on molecular packing and ordering of the shell components in the films, which relates to the molecular interactions and interfacial reactivities. ESR probes the conduction electron spin resonance properties of the nanosized cores, which can be correlated with the network or environmental electronic effects on the crystal cores. Results are discussed in terms of their correlation with the nanoparticle core sizes and the organic shell functionality.

  6. 2D SIMPLIFIED SERVO VALVE

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A novel pilot stage valve called simplified 2D valve, which utilizes both rotary and linear motions of a single spool, is presented.The rotary motion of the spool incorporating hydraulic resistance bridge, formed by a damper groove and a crescent overlap opening, is utilized as pilot to actuate linear motion of the spool.A criterion for stability is derived from the linear analysis of the valve.Special experiments are designed to acquire the mechanical stiffness, the pilot leakage and the step response.It is shown that the sectional size of the spiral groove affects the dynamic response and the stiffness contradictorily and is also very sensitive to the pilot leakage.Therefore, it is necessary to establish a balance between the static and dynamic characteristics in deciding the structural parameters.Nevertheless, it is possible to sustain the dynamic response at a fairly high level, while keeping the leakage of the pilot stage at an acceptable level.

  7. Personalized 2D color maps

    KAUST Repository

    Waldin, Nicholas

    2016-06-24

    2D color maps are often used to visually encode complex data characteristics such as heat or height. The comprehension of color maps in visualization is affected by the display (e.g., a monitor) and the perceptual abilities of the viewer. In this paper we present a novel method to measure a user\\'s ability to distinguish colors of a two-dimensional color map on a given monitor. We show how to adapt the color map to the user and display to optimally compensate for the measured deficiencies. Furthermore, we improve user acceptance of the calibration procedure by transforming the calibration into a game. The user has to sort colors along a line in a 3D color space in a competitive fashion. The errors the user makes in sorting these lines are used to adapt the color map to his perceptual capabilities.

  8. Modeling for proximate analysis and heating value of torrefied biomass with vibration spectroscopy.

    Science.gov (United States)

    Via, Brian K; Adhikari, Sushil; Taylor, Steve

    2013-04-01

    The goal of this study was to characterize the changes in biomass with torrefaction for near infrared reflectance (NIR) and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy for sweetgum, loblolly pine, and switchgrass. Calibration models were built for the prediction of proximate analysis after torrefaction. Two dimensional (2D) correlation spectroscopy between NIR and FTIR was found to precisely explain the depolymerization at key functional groups located within hemicellulose, cellulose, and lignin. This novel 2D technique also demonstrated the possibility of assigning key NIR wavenumbers based on mid IR spectra. Hemicellulose based wavenumbers were found to be most sensitive to torrefaction severity with complete degradation at 250-275°C. Lignin associated wavenumbers exhibited the least degradation to severity but was still detected with 2D correlation spectroscopy. Finally, calibration models for proximate analysis were performed and while both systems could be used for rapid monitoring, NIR performed better than FTIR.

  9. CH2D+, the Search for the Holy Grail

    Science.gov (United States)

    Roueff, Evelyne; Gerin, Maryvonne; Lis, Dariusz C.; Wootten, Alwyn; Marcelino, Nuria; Cernicharo, Jose; Tercero, Belen

    2013-10-01

    CH2D+, the singly deuterated counterpart of CH3+, offers an alternative way to mediate formation of deuterated species at temperatures of several tens of Kelvin, as compared to the release of deuterated species from grains. We report a longstanding observational search for this molecular ion, whose rotational spectroscopy is not yet completely secure. We summarize the main spectroscopic properties of this molecule and discuss the chemical network leading to the formation of CH2D+, with explicit account of the ortho/para forms of H2, H3+, and CH3+. Astrochemical models support the presence of this molecular ion in moderately warm environments at a marginal level.

  10. CH2D+, the Search for the Holy Grail

    CERN Document Server

    Roueff, E; Lis, D C; Wootten, A; Marcelino, N; cernicharo, J; Tercero, B

    2013-01-01

    CH2D+, the singly deuterated counterpart of CH3+, offers an alternative way to mediate formation of deuterated species at temperatures of several tens of K, as compared to the release of deuterated species from grains. We report a longstanding observational search for this molecular ion, whose rotational spectroscopy is not yet completely secure. We summarize the main spectroscopic properties of this molecule and discuss the chemical network leading to the formation of CH2D+, with explicit account of the ortho/para forms of H2, H3+ and CH3+. Astrochemical models support the presence of this molecular ion in moderately warm environments at a marginal level.

  11. Ultrafast Structural Fluctuations of Myoglobin-Bound Thiocyanate and Selenocyanate Ions Measured with Two-Dimensional Infrared Photon Echo Spectroscopy.

    Science.gov (United States)

    Maj, Michał; Kwak, Kyungwon; Cho, Minhaeng

    2015-11-16

    Structural dynamics within the distal cavity of myoglobin protein is investigated using 2D-IR and IR pump-probe spectroscopy of the N≡C stretch modes of heme-bound thiocyanate and selenocyanate ions. Although myoglobin-bound thiocyanate group shows a doublet in its IR absorption spectrum, no cross peaks originating from chemical exchange between the two components are observed in the time-resolved 2D IR spectra within the experimental time window. Frequency-frequency correlation functions of the two studied anionic ligands are obtained by means of a few different analysis approaches; these functions were then used to elucidate the differences in structural fluctuation around ligand, ligand-protein interactions, and the degree of structural heterogeneity within the hydrophobic pocket of these myoglobin complexes.

  12. Filament-induced visible-to-mid-IR supercontinuum in a ZnSe crystal: Towards multi-octave supercontinuum absorption spectroscopy

    Science.gov (United States)

    Mouawad, O.; Béjot, P.; Billard, F.; Mathey, P.; Kibler, B.; Désévédavy, F.; Gadret, G.; Jules, J.-C.; Faucher, O.; Smektala, F.

    2016-10-01

    We report on the generation of multiple-octave supercontinuum laser source spanning from 0.5 μm to 11 μm induced by multi-filamentation in a ZnSe crystal. The generated supercontinuum is both spatially and spectrally characterized. It is then exploited in a proof-of-principle experiment for methane spectroscopy measurements by means of the supercontinuum absorption spectroscopy technique. The entire absorption spectrum is successfully recorded within the whole spectral bandwidth of the supercontinuum. Experimental results are in fairly good agreement with the HITRAN database, confirming the reliability and stability over several hours of the generated supercontinuum.

  13. Improve the Absolute Accuracy of Ozone Intensities in the 9-11 μm Region via Mw/ir Multi-Wavelength Spectroscopy

    Science.gov (United States)

    Yu, Shanshan; Drouin, Brian

    2016-06-01

    Ozone (O_3) is crucial for studies of air quality, human and crop health, and radiative forcing. Spectroscopic remote sensing techniques have been extensively employed to investigate ozone globally and regionally. Infrared intensities of ≤1% accuracy are desired by the remote sensing community. The accuracy of the current state-of-the-art infrared ozone intensities is on the order of 4-10%, resulting in ad hoc intensity scaling factors for consistent atmospheric retrievals. The large uncertainties on the infrared ozone intensities arise from the fact that pure ozone is very difficult to generate and sustain in the laboratory. Best estimates have employed IR/UV cross beam experiments to determine the accurate O_3 volume mixing ratio of the sample through its standard cross section value at 254 nm. This presentation reports our effort to improve the absolute accuracy of ozone intensities in the 9-11 μm region via a transfer of the precision of the rotational dipole moment onto the infrared measurement (MW/IR). Our approach was to use MW/IR cross beam experiments and determine the O_3 mixing ratio through alternately measuring pure rotation ozone lines from 692 to 779 GHz. The uncertainty of these pure rotation line intensities is better than 0.1%. The sample cell was a slow flow cross cell and the total pressure inside the sample cell was maintained constant through a proportional-integral-derivative (PID) flow control. Five infrared O_3 spectra were obtained, with a path length of 3.74 m, pressures ranging from 30 to 120 mTorr, and mixing ratio ranging from 0.5 to 0.9. A multi spectrum fitting technique was employed to fit all the FTS spectra simultaneously. The results show that we can determine intensities of the 9.6μm band with absolute accuracy better than 4%.

  14. Etude de la caractérisation et la composition qualitative des huiles essentielles de six plantes médicinales par spectroscopie IR

    Directory of Open Access Journals (Sweden)

    N. BELBOUKHARI

    2013-03-01

    Full Text Available La séparation et l’identification des constituants des huiles essentielles des plantes ou d’autres sources naturels basée largement sur la chromatographie en phase gazeuse. Dans ce travail on nous développons des techniques de comparaison qui évitent en premier temps la séparation chromatographique, on se basant sur la comparaison des spectres infra rouge (IR des huiles essentielles avec celle des terpènes et sesquiterpènes purs qui constituent en majorité les huiles essentielles.

  15. Time-resolved UV-IR pump-stimulated emission pump spectroscopy to probe collisional relaxation of $8p\\,^2P_{3/2}$ Cs I

    CERN Document Server

    Salahuddin, Mohammed; McFarland, Jacob; Bayram, S Burcin

    2015-01-01

    We describe and use a time-resolved pump-stimulated emission pump spectroscopic technique to measure collisional relaxation in a high-lying energy level of atomic cesium. Aligned $8p\\,^2P_{3/2}$ cesium atoms were produced by a pump laser. A second laser, the stimulated emission pump, promoted the population exclusively to the $5d\\,^2D_{5/2}$ level. The intensity of the $5d\\,^2D_{5/2}\\rightarrow6s\\,^2S_{1/2}$ cascade fluorescence at 852.12 nm was monitored. The linear polarization dependence of the $6s\\,^2S_{1/2}\\rightarrow8p\\,^2P_{3/2}\\rightarrow5d\\,^2S_{5/2}$ transition was measured in the presence of argon gas at various pressures. From the measurement, we obtained the disalignment cross section value for the $8p\\,^2P_{3/2}$ level due to collisions with ground-level argon atoms.

  16. Kinetics of the F+NO2+M->FNO2+M reaction studied by pulse radiolysis combined with time-resolved IR and UV spectroscopy

    DEFF Research Database (Denmark)

    Pagsberg, Palle Bjørn; Sillesen, A.; Jodkowski, J.T.;

    1996-01-01

    The title reaction was initiated by the pulse radiolysis of SF6/NO2 gas mixtures, and the formation of FNO2 was studied by time-resolved infrared spectroscopy employing strong rotational transitions within the nu(1) and nu(4) bands of FNO2. The pressure dependence of the formation kinetics...

  17. Learn Unity for 2D game development

    CERN Document Server

    Thorn, Alan

    2013-01-01

    The only Unity book specifically covering 2D game development Written by Alan Thorn, experience game developer and author of seven books on game programming Hands-on examples of all major aspects of 2D game development using Unity

  18. Spectroscopic and structural studies of quinoline derivatives—II. Forrier transform i.r. spectroscopy. 1. Rotational isomerism in 3-ethoxycarbonyl-4(1H)-quinolone and some of its substituted derivatives,

    Science.gov (United States)

    Mirek, Julian; Urbanek, Zbigniew H.

    Rotational isomerism associated with internal rotation about the ring carbon(3)-ester carbonyl carbon single bond in a series of 3-ethoxycarbonyl-4(1H)-quinolones have been investigated spectroscopically in the solid state using Fourier transform i.r. and laser Raman spectroscopy. Particular attention is given to the 1700, 1300 and 1100 cm -1 spectral regions related primarily to the vibrations of the CO 2C 2H 5 group. Within these regions rotational isomerism appeared in the compounds examined. The conformational changes are discussed and evidence is reported for occurrence of the unsubstituted compound 1 itself in the solid state at ambient temperature as an equilibrium mixture of both the s-trans ( 1a) and s-cis ( 1b) rotamers (this is in contrast to previous findings), and of its Bz-substituted derivatives.

  19. Spectroscopy (FT-IR, FT-Raman), hydrogen bonding, electrostatic potential and HOMO-LUMO analysis of tioxolone based on DFT calculations

    Science.gov (United States)

    Tao, Yaping; Li, Xiaofeng; Han, Ligang; Zhang, Weiying; Liu, Zhaojun

    2016-10-01

    Tioxolone possess antipsoriatic and antibacterial properties. Therefore, it has been used in treating various skin and scalp disorders for many years. Spectroscopic analysis of tioxolone was presented by using density functional theory (DFT) calculations and experiments (FT-IR, FT-Raman and UV-Vis). Molecular geometry and vibrational wavenumbers of tioxolone were investigated by using B3LYP method with aug-cc-pVTZ basis set. A complete vibrational spectra was made to analyze the potential energy distributions (PED). In addition, analysis of frontier molecular orbitals, electrostatic potential (ESP) and thermodynamic properties (heat capacity, entropy, enthalpy and Gibbs free energy) was presented with the same basis-set. Furthermore, the nature of molecular association through hydrogen bonding were discussed using atoms in molecules (AIM) and reduced density gradient (RDG) methods.

  20. DFG-based mid-IR generation using a compact dual-wavelength all-fiber amplifier for laser spectroscopy applications.

    Science.gov (United States)

    Krzempek, Karol; Sobon, Grzegorz; Abramski, Krzysztof M

    2013-08-26

    We demonstrate a compact mid-infrared (mid-IR) radiation source based on difference frequency generation (DFG) in periodically poled lithium niobate (PPLN) crystal. The system incorporates a dual-wavelength master oscillator power amplifier (MOPA) source capable of simultaneous amplification of 1064 nm and 1548 nm signals in a common active fiber co-doped with erbium and ytterbium ions. Two low-power seed lasers were amplified by a factor of 14.4 dB and 23.7 dB for 1064 nm and 1548 nm, respectively and used in a nonlinear DFG setup to generate 1.14 mW of radiation centered at 3.4 μm. The system allowed for open-path detection of methane (CH(4)) in ambient air with estimated minimum detectable concentration at a level of 26 ppbv. PMID:24105549

  1. Risk assessment of an old landfill regarding the potential of gaseous emissions--a case study based on bioindication, FT-IR spectroscopy and thermal analysis.

    Science.gov (United States)

    Tintner, Johannes; Smidt, Ena; Böhm, Katharina; Matiasch, Lydia

    2012-12-01

    Risk assessment of two sections (I and II) of an old landfill (ALH) in Styria (Austria) in terms of reactivity of waste organic matter and the related potential of gaseous emissions was performed using conventional parameters and innovative tools to verify their effectiveness in practice. The ecological survey of the established vegetation at the landfill surface (plant sociological relevés) indicated no relevant emissions over a longer period of time. Statistical evaluation of conventional parameters reveals that dissolved organic carbon (DOC), respiration activity (RA(4)), loss of ignition (LOI) and total inorganic carbon (TIC) mostly influence the variability of the gas generation sum (GS(21)). According to Fourier Transform Infrared (FT-IR) spectral data and the results of the classification model the reactivity potential of the investigated sections is very low which is in accordance with the results of plant sociological relevés and biological tests. The interpretation of specific regions in the FT-IR spectra was changed and adapted to material characteristics. Contrary to mechanically-biologically treated (MBT) materials, where strong aliphatic methylene bands indicate reactivity, they are rather assigned to the C-H vibrations of plastics in old landfill materials. This assumption was confirmed by thermal analysis and the characteristic heat flow profile of plastics containing landfill samples. Therefore organic carbon contents are relatively high compared to other stable landfills as shown by a prediction model for TOC contents based on heat flow profiles and partial least squares regression (PLS-R). The stability of the landfill samples, expressed by the relation of CO(2) release and enthalpies, was compared to unreactive landfills, archeological samples, earthlike materials and hardly degradable organic matter. Due to the material composition and the aging process the landfill samples are located between hardly degradable, but easily combustible

  2. Currency verification by a 2D infrared barcode

    International Nuclear Information System (INIS)

    Nowadays all the National Central Banks are continuously studying innovative anti-counterfeiting systems for banknotes. In this note, an innovative solution is proposed, which combines the potentiality of a hylemetric approach (methodology conceptually similar to biometry), based on notes' intrinsic characteristics, with a well-known and consolidated 2D barcode identification system. In particular, in this note we propose to extract from the banknotes a univocal binary control sequence (template) and insert an encrypted version of it in a barcode printed on the same banknote. For a more acceptable look and feel of a banknote, the superposed barcode can be stamped using IR ink that is visible to near-IR image sensors. This makes the banknote verification simpler. (technical design note)

  3. Long-distance inter-hydrogen bond coupling effects in the polarized IR spectra of succinic acid crystals

    Science.gov (United States)

    Flakus, Henryk T.; Hachuła, Barbara; Hołaj-Krzak, Jakub T.

    2015-05-01

    The spectral properties of four different crystalline succinic acid (HOOC-(CH2)2-COOH) (SAC) isotopomer systems, h6, d2, d4 and d6, were examined by means of the IR spectroscopy in polarized light aided by numerical simulations of the νO-H and νO-D band contour shapes on utilizing the "strong-coupling" model. The abnormal IR spectral properties of SAC crystals in relation to the corresponding properties of glutaric, pimelic and adipic acid crystals were ascribed to the hyperconjugation electronic effects in the acid associated molecules. A vibronic coupling mechanism involving the proton stretching vibrations in the (COOH)2 cycles and the electronic motions in the molecular skeletons, the isotopic "H/D self-organization" mechanisms and a long-distance vibrational exciton coupling between the adjacent (COOH)2 cycles in the molecular chains are mainly responsible for the generation of the temperature effects in the crystalline IR spectra.

  4. Direct Observation by Rapid-Scan FT-IR Spectroscopy of Two-Electron-Reduced Intermediate of Tetraaza Catalyst [Co(II)N4H(MeCN)](2+) Converting CO2 to CO.

    Science.gov (United States)

    Sheng, Hua; Frei, Heinz

    2016-08-10

    In the search for the two-electron-reduced intermediate of the tetraaza catalyst [Co(II)N4H(MeCN)](2+) (N4H = 2,12-dimethyl-3,7,11,17-tetraazabicyclo[11.3.1]heptadeca-1(17),2,11,13,15-pentaene) for CO2 reduction and elementary steps that result in the formation of CO product, rapid-scan FT-IR spectroscopy of the visible-light-sensitized catalysis, using Ir(ppy)3 in wet acetonitrile (CD3CN) solution, led to the observation of two sequential intermediates. The initially formed one-electron-reduced [Co(I)N4H](+)-CO2 adduct was converted by the second electron to a transient [Co(I)N4H](+)-CO2(-) complex that spontaneously converted CO2 to CO in a rate-limiting step on the second time scale in the dark under regeneration of the catalyst (room temperature). The macrocycle IR spectra of the [Co(I)N4H](+)-CO2(-) complex and the preceding one-electron [Co(I)N4H](+)-CO2 intermediate show close similarity but distinct differences in the carboxylate modes, indicating that the second electron resides mainly on the CO2 ligand. Vibrational assignments are corroborated by (13)C isotopic labeling. The structure and stability of the two-electron-reduced intermediate derived from the time-resolved IR study are in good agreement with recent predictions by DFT electronic structure calculations. This is the first observation of an intermediate of a molecular catalyst for CO2 reduction during the bond-breaking step producing CO. The reaction pathway for the Co tetraaza catalyst uncovered here suggests that the competition between CO2 reduction and proton reduction of a macrocyclic multi-electron catalyst is steered toward CO2 activation if the second electron is directly captured by an adduct of CO2 and the one-electron-reduced catalyst intermediate.

  5. Hα Star Formation Rates for z>1 Galaxy Clusters in the IRAC Shallow Cluster Survey Using WFC3 IR Grism Spectroscopy

    Science.gov (United States)

    Zeimann, Gregory; Stanford, A.; Brodwin, M.; Dey, A.; Stern, D.; Gonzalez, A.

    2011-05-01

    We present new HST WFC3 grism data for 17 z>1 galaxy clusters in the IRAC Shallow Cluster Survey (ISCS). Using the G141 grism (λ = 1.10 - 1.65 μm, 46.5 A/pixel), we identified ˜5-15 new cluster members in each cluster candidate with a visual inspection of emission line galaxies in the reduced 1-d and 2-d spectral extractions. Given the redshift range of the cluster candidates and the wavelength coverage of the G141 grism, the emission line most identified was the blended Hα+NII. Correlations found in the literature between the EW of Hα+NII and the line ratio of NII to Hα were used to deblend the two fluxes. Hα emission was used as an indicator of star formation. Our program is sensitive to an unobscured star formation rate of 4 M⊙ / Year for z=1.5 and a nominal 1:4 ratio of NII to Hα. Concurrent MIPS 24μm data allows for the comparison of different SFR tracers. Whenever possible, we also use the ratio of Hβ/Hα to estimate dust obscuration and correct the SFRs. This dataset allows the study of a wide-range of star formation rates in dense cluster cores during the peak epoch of galaxy formation.

  6. Spitzer IRS Spectroscopy of the 10 Myr-old EF Cha Debris Disk: Evidence for Phyllosilicate-Rich Dust in the Terrestrial Zone

    CERN Document Server

    Currie, Thayne; Sicilia-Aguilar, Aurora; Rieke, George H; Su, Kate

    2011-01-01

    We describe Spitzer IRS spectroscopic observations of the 10 Myr-old star, EF Cha. Compositional modeling of the spectra from 5 {\\mu}m to 35 {\\mu}m confirms that it is surrounded by a luminous debris disk with LD/L\\star ~ 10-3, containing dust with temperatures between 225 K and 430 K characteristic of the terrestrial zone. The EF Cha spectrum shows evidence for many solid-state features, unlike most cold, low-luminosity debris disks but like some other 10-20 Myr-old luminous, warm debris disks (e.g. HD 113766A). The EF Cha debris disk is unusually rich in a species or combination of species whose emissivities resemble that of finely powdered, laboratory-measured phyllosilicate species (talc, saponite, and smectite), which are likely produced by aqueous alteration of primordial anhydrous rocky materials. The dust and, by inference, the parent bodies of the debris also contain abundant amorphous silicates and metal sulfides, and possibly water ice. The dust's total olivine to pyroxene ratio of ~ 2 also provide...

  7. Effect of organic carbon chemistry on sorption of atrazine and metsulfuron-methyl as determined by (13)C-NMR and IR spectroscopy.

    Science.gov (United States)

    Dutta, Anirban; Mandal, Abhishek; Manna, Suman; Singh, S B; Berns, Anne E; Singh, Neera

    2015-10-01

    Soil organic matter (SOM) content is the major soil component affecting pesticide sorption. However, recent studies have highlighted the fact that it is not the total carbon content of the organic matter, but its chemical structure which have a profound effect on the pesticide's sorption. In the present study, sorption of atrazine and metsulfuron-methyl herbicides was studied in four SOM fractions viz. commercial humic acid, commercial lignin, as well as humic acid and humin extracted from a compost. Sorption data was fitted to the Freundlich adsorption equation. In general, the Freundlich slope (1/n) values for both the herbicides were herbicides, showed minimum desorption. Sorption of atrazine was best positively correlated with the alkyl carbon (adjusted R (2) = 0.748) and carbonyl carbon (adjusted R (2) = 0.498) but, their effect was statistically nonsignificant (P = 0.05). Metsulfuron-methyl sorption showed best positive correlation with carbonyl carbon (adjusted R (2) = 0.960; P = 0.05) content. Sorption of both the herbicides showed negative correlation with O/N-alkyl carbon. Correlation of herbicide's sorption with alkyl and carbonyl carbon content of SOM fractions suggested their contribution towards herbicide sorption. But, sorption of metsulfuron-methyl, relatively more polar than atrazine, was mainly governed by the polar groups in SOM. IR spectra showed that H-bonds and charge-transfer bonds between SOM fraction and herbicides probably operated as mechanisms of adsorption. PMID:26353968

  8. A simple but accurate potential for the naphthalene-argon complex: applications to collisional energy transfer and matrix isolated IR spectroscopy.

    Science.gov (United States)

    Calvo, F; Falvo, Cyril; Parneix, Pascal

    2013-01-21

    An explicit polarizable potential for the naphthalene-argon complex has been derived assuming only atomic contributions, aiming at large scale simulations of naphthalene under argon environment. The potential was parametrized from dedicated quantum chemical calculations at the CCSD(T) level, and satisfactorily reproduces available structural and energetic properties. Combining this potential with a tight-binding model for naphthalene, collisional energy transfer is studied by means of dedicated molecular dynamics simulations, nuclear quantum effects being accounted for in the path-integral framework. Except at low target temperature, nuclear quantum effects do not alter the average energies transferred by the collision or the collision duration. However, the distribution of energy transferred is much broader in the quantum case due to the significant zero-point energy and the higher density of states. Using an ab initio potential for the Ar-Ar interaction, the IR absorption spectrum of naphthalene solvated by argon clusters or an entire Ar matrix is computed via classical and centroid molecular dynamics. The classical spectra exhibit variations with growing argon environment that are absent from quantum spectra. This is interpreted by the greater fluxional character experienced by the argon atoms due to vibrational delocalization.

  9. Time-resolved spectral characterization of ring cavity surface emitting and ridge-type distributed feedback quantum cascade lasers by step-scan FT-IR spectroscopy.

    Science.gov (United States)

    Brandstetter, Markus; Genner, Andreas; Schwarzer, Clemens; Mujagic, Elvis; Strasser, Gottfried; Lendl, Bernhard

    2014-02-10

    We present the time-resolved comparison of pulsed 2nd order ring cavity surface emitting (RCSE) quantum cascade lasers (QCLs) and pulsed 1st order ridge-type distributed feedback (DFB) QCLs using a step-scan Fourier transform infrared (FT-IR) spectrometer. Laser devices were part of QCL arrays and fabricated from the same laser material. Required grating periods were adjusted to account for the grating order. The step-scan technique provided a spectral resolution of 0.1 cm(-1) and a time resolution of 2 ns. As a result, it was possible to gain information about the tuning behavior and potential mode-hops of the investigated lasers. Different cavity-lengths were compared, including 0.9 mm and 3.2 mm long ridge-type and 0.97 mm (circumference) ring-type cavities. RCSE QCLs were found to have improved emission properties in terms of line-stability, tuning rate and maximum emission time compared to ridge-type lasers.

  10. Two-dimensional electronic spectroscopy with birefringent wedges

    Energy Technology Data Exchange (ETDEWEB)

    Réhault, Julien; Maiuri, Margherita; Oriana, Aurelio; Cerullo, Giulio [IFN-CNR, Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano (Italy)

    2014-12-15

    We present a simple experimental setup for performing two-dimensional (2D) electronic spectroscopy in the partially collinear pump-probe geometry. The setup uses a sequence of birefringent wedges to create and delay a pair of phase-locked, collinear pump pulses, with extremely high phase stability and reproducibility. Continuous delay scanning is possible without any active stabilization or position tracking, and allows to record rapidly and easily 2D spectra. The setup works over a broad spectral range from the ultraviolet to the near-IR, it is compatible with few-optical-cycle pulses and can be easily reconfigured to two-colour operation. A simple method for scattering suppression is also introduced. As a proof of principle, we present degenerate and two-color 2D spectra of the light-harvesting complex 1 of purple bacteria.

  11. Nanoscale probing of electron-regulated structural transitions in silk proteins by near-field IR imaging and nano-spectroscopy

    Science.gov (United States)

    Qin, Nan; Zhang, Shaoqing; Jiang, Jianjuan; Corder, Stephanie Gilbert; Qian, Zhigang; Zhou, Zhitao; Lee, Woonsoo; Liu, Keyin; Wang, Xiaohan; Li, Xinxin; Shi, Zhifeng; Mao, Ying; Bechtel, Hans A.; Martin, Michael C.; Xia, Xiaoxia; Marelli, Benedetto; Kaplan, David L.; Omenetto, Fiorenzo G.; Liu, Mengkun; Tao, Tiger H.

    2016-01-01

    Silk protein fibres produced by silkworms and spiders are renowned for their unparalleled mechanical strength and extensibility arising from their high-β-sheet crystal contents as natural materials. Investigation of β-sheet-oriented conformational transitions in silk proteins at the nanoscale remains a challenge using conventional imaging techniques given their limitations in chemical sensitivity or limited spatial resolution. Here, we report on electron-regulated nanoscale polymorphic transitions in silk proteins revealed by near-field infrared imaging and nano-spectroscopy at resolutions approaching the molecular level. The ability to locally probe nanoscale protein structural transitions combined with nanometre-precision electron-beam lithography offers us the capability to finely control the structure of silk proteins in two and three dimensions. Our work paves the way for unlocking essential nanoscopic protein structures and critical conditions for electron-induced conformational transitions, offering new rules to design protein-based nanoarchitectures. PMID:27713412

  12. Perspectives for spintronics in 2D materials

    Directory of Open Access Journals (Sweden)

    Wei Han

    2016-03-01

    Full Text Available The past decade has been especially creative for spintronics since the (rediscovery of various two dimensional (2D materials. Due to the unusual physical characteristics, 2D materials have provided new platforms to probe the spin interaction with other degrees of freedom for electrons, as well as to be used for novel spintronics applications. This review briefly presents the most important recent and ongoing research for spintronics in 2D materials.

  13. Surface modelling for 2D imagery

    OpenAIRE

    Lieng, Henrik

    2014-01-01

    Vector graphics provides powerful tools for drawing scalable 2D imagery. With the rise of mobile computers, of different types of displays and image resolutions, vector graphics is receiving an increasing amount of attention. However, vector graphics is not the leading framework for creating and manipulating 2D imagery. The reason for this reluctance of employing vector graphical frameworks is that it is difficult to handle complex behaviour of colour across the 2D domain. ...

  14. Perspectives for Spintronics in 2D Materials

    OpenAIRE

    Wei Han

    2016-01-01

    The past decade has been especially creative for spintronics since the (re)discovery of various two dimensional (2D) materials. Due to the unusual physical characteristics, 2D materials have provided new platforms to probe the spin interaction with other degrees of freedom for electrons, as well as to be used for novel spintronics applications. This review briefly presents the most important recent and ongoing research for spintronics in 2D materials.

  15. Direct Observation of the Kinetically Relevant Site of CO Hydrogenation on Supported Ru Catalyst at 700 K by Time-Resolved FT-IR Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Frei, Heinz; Wasylenko, Walter; Frei, Heinz

    2008-06-04

    Time-resolved FT-IR spectra of carbon monoxide hydrogenation over alumina-supported ruthenium particles were recorded on themillisecond time scale at 700 K using pulsed release of CO and a continuous flow of H2/N2 (ratio 0.067 or 0.15, 1 atm total pressure). Adsorbed carbon monoxide was detected along with gas phase products methane (3016 and 1306 cm-1), water (1900 +- 1300 cm-1), and carbon dioxide (2348 cm-1). Aside from adsorbed CO, no other surface species were observed. The rate of formation of methane is 2.5 +- 0.4 s-1 and coincides with the rate of carbon dioxide growth (3.4 +- 0.6 s-1), thus indicating that CH4 and CO2 originate from a common intermediate. The broad band of adsorbed carbon monoxide has a maximum at 2010 cm-1 at early times (36 ms) that shifts gradually to 1960 cm-1 over a period of 3 s as a result of the decreasing surface concentration of CO. Kinetic analysis of the adsorbed carbon monoxide reveals that surface sites absorbing at the high frequency end of the infrared band are temporally linked to gas phase product growth. Specifically, a (linear) CO site at 2026 cm-1 decays with a rate constant of 2.9 +- 0.1 s-1, which coincides with the rise constant of CH4. This demonstrates that the linear CO site at 2026 cm-1 is the kinetically most relevant one for the rate-determining CO dissociation step under reaction conditions at 700 K.

  16. Effect of organic carbon chemistry on sorption of atrazine and metsulfuron-methyl as determined by (13)C-NMR and IR spectroscopy.

    Science.gov (United States)

    Dutta, Anirban; Mandal, Abhishek; Manna, Suman; Singh, S B; Berns, Anne E; Singh, Neera

    2015-10-01

    Soil organic matter (SOM) content is the major soil component affecting pesticide sorption. However, recent studies have highlighted the fact that it is not the total carbon content of the organic matter, but its chemical structure which have a profound effect on the pesticide's sorption. In the present study, sorption of atrazine and metsulfuron-methyl herbicides was studied in four SOM fractions viz. commercial humic acid, commercial lignin, as well as humic acid and humin extracted from a compost. Sorption data was fitted to the Freundlich adsorption equation. In general, the Freundlich slope (1/n) values for both the herbicides were <1. Except for atrazine sorption on commercial humic acid, metsulfuron-methyl was more sorbed. Desorption results suggested that atrazine was more desorbed than metsulfuron-methyl. Lignin, which showed least sorption of both the herbicides, showed minimum desorption. Sorption of atrazine was best positively correlated with the alkyl carbon (adjusted R (2) = 0.748) and carbonyl carbon (adjusted R (2) = 0.498) but, their effect was statistically nonsignificant (P = 0.05). Metsulfuron-methyl sorption showed best positive correlation with carbonyl carbon (adjusted R (2) = 0.960; P = 0.05) content. Sorption of both the herbicides showed negative correlation with O/N-alkyl carbon. Correlation of herbicide's sorption with alkyl and carbonyl carbon content of SOM fractions suggested their contribution towards herbicide sorption. But, sorption of metsulfuron-methyl, relatively more polar than atrazine, was mainly governed by the polar groups in SOM. IR spectra showed that H-bonds and charge-transfer bonds between SOM fraction and herbicides probably operated as mechanisms of adsorption.

  17. UNITS IN $F_2D_{2p}$

    OpenAIRE

    Kaur, Kuldeep; Khan, Manju

    2012-01-01

    Let $p$ be an odd prime, $D_{2p}$ be the dihedral group of order 2p, and $F_{2}$ be the finite field with two elements. If * denotes the canonical involution of the group algebra $F_2D_{2p}$, then bicyclic units are unitary units. In this note, we investigate the structure of the group $\\mathcal{B}(F_2D_{2p})$, generated by the bicyclic units of the group algebra $F_2D_{2p}$. Further, we obtain the structure of the unit group $\\mathcal{U}(F_2D_{2p})$ and the unitary subgroup $\\mathcal{U}_*(F_...

  18. 2D Barcode for DNA Encoding

    CERN Document Server

    Purcaru, Elena

    2012-01-01

    The paper presents a solution for endcoding/decoding DNA information in 2D barcodes. First part focuses on the existing techniques and symbologies in 2D barcodes field. The 2D barcode PDF417 is presented as starting point. The adaptations and optimizations on PDF417 and on DataMatrix lead to the solution - DNA2DBC - DeoxyriboNucleic Acid Two Dimensional Barcode. The second part shows the DNA2DBC encoding/decoding process step by step. In conclusions are enumerated the most important features of 2D barcode implementation for DNA.

  19. 2D Barcode for DNA Encoding

    Directory of Open Access Journals (Sweden)

    Elena Purcaru

    2011-09-01

    Full Text Available The paper presents a solution for endcoding/decoding DNA information in 2D barcodes. First part focuses on the existing techniques and symbologies in 2D barcodes field. The 2D barcode PDF417 is presented as starting point. The adaptations and optimizations on PDF417 and on DataMatrix lead to the solution – DNA2DBC – DeoxyriboNucleic Acid Two Dimensional Barcode. The second part shows the DNA2DBC encoding/decoding process step by step. In conclusions are enumerated the most important features of 2D barcode implementation for DNA.

  20. Vibrational ladder-climbing in surface-enhanced, ultrafast infrared spectroscopy.

    Science.gov (United States)

    Kraack, Jan Philip; Hamm, Peter

    2016-06-28

    In a recent work (J. Phys. Chem. C 2016, 120, 3350-3359), we have introduced the concept of surface-enhanced, two-dimensional attenuated total reflectance (2D ATR IR) spectroscopy with modest enhancement factors (450), which allows for multi-quantum IR excitation of adsorbed molecules, a process known as "vibrational ladder-climbing", even for weakly absorbing (ε ultrafast dynamics of highly excited vibrational states or surface-sensitive coherent control experiments of ground-state reactions at solid-liquid interfaces. PMID:27265518

  1. Quadrature two-dimensional correlation spectroscopy (Q-2DCOS)

    Science.gov (United States)

    Noda, Isao

    2016-11-01

    Quadrature 2D correlation spectroscopy (Q-2DCOS) is introduced. The technique incorporates the effect of the perturbation into the traditional 2DCOS analysis by building a multivariate model, merging the information of the perturbation variable and spectral responses. By employing factors which are 90° out of phase with each other, pertinent coincidental and sequential spectral intensity variations are adequately captured for the subsequent 2D correlation analysis. Almost complete replication of the original 2DCOS results based on such a simple rank 2 model of experimental spectra suggests that only the dominant spectral intensity variation patterns in combination with its quadrature counterpart seems to be utilized in 2DCOS analysis. Using the linear perturbation variable itself as the basis for generating the primary score vector is equivalent to the least squares fitting of a quadratic polynomial with spectral intensity variations. Q-2DCOS analysis may be displayed in terms of a graphical plot on a phase plane in the vector space, so that coincidental and sequential matching of the patterns of spectral intensity variations is represented simply by the phase angle difference between two vectors. Q-2DCOS analysis is closely related to other established ideas and practices in the 2D correlation spectroscopy field, such as dynamic 2D IR dichroism, PCA 2D, quadrature orthogonal signal correction (Q-OSC), and perturbation correlation moving window (PCMW) analyses.

  2. Monitoring the dissolution of Active Pharmaceutical Ingredient and TPGS in real time via IR spectroscopy during the manufacturing of liquid dosage formulation.

    Science.gov (United States)

    Šašić, Slobodan; Palm, Andrew S; Tang, Degui

    2012-11-01

    Infrared spectroscopy is used to monitor the dissolution of the Active Pharmaceutical Ingredient (API) and an excipient (vitamin E - TPGS) during manufacturing of a liquid pharmaceutical formulation. The goal of the analysis is to explore options for real-time, on screen, and quantitative monitoring of these two components by using an iC10 instrument. As is common, the first step in the approach is to create respective calibration models for the two components and then apply those models on the spectra obtained from scale-up batches. Interestingly, while the API dissolves at the room temperature, TPGS dissolves at an acceptable rate at 50 °C so both temperatures have to be considered. It is shown that univariate models of sufficient accuracy can be developed with a straightforward applicability to the scale-up batches spectra and providing reasonably accurate estimates of the API and TPGS concentrations. Some limitations of the software on the employed instrument may diminish the prospect for the quantitative analysis of the components of interest in this formulation. PMID:22871426

  3. Time-Resolved Quantitative Measurement of OH HO2 and CH2O in Fuel Oxidation Reactions by High Resolution IR Absorption Spectroscopy.

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Haifeng; Rotavera, Brandon; Taatjes, Craig A.

    2014-08-01

    Combined with a Herriott-type multi-pass slow flow reactor, high-resolution differential direct absorption spectroscopy has been used to probe, in situ and quantitatively, hydroxyl (OH), hydroperoxy (HO 2 ) and formaldehyde (CH 2 O) molecules in fuel oxidation reactions in the reactor, with a time resolution of about 1 micro-second. While OH and CH 2 O are probed in the mid-infrared (MIR) region near 2870nm and 3574nm respectively, HO 2 can be probed in both regions: near-infrared (NIR) at 1509nm and MIR at 2870nm. Typical sensitivities are on the order of 10 10 - 10 11 molecule cm -3 for OH at 2870nm, 10 11 molecule cm -3 for HO 2 at 1509nm, and 10 11 molecule cm -3 for CH 2 O at 3574nm. Measurements of multiple important intermediates (OH and HO 2 ) and product (CH 2 O) facilitate to understand and further validate chemical mechanisms of fuel oxidation chemistry.

  4. The complex, dusty narrow-line region of NGC 4388: Gas-jet interactions, outflows, and extinction revealed by near-IR spectroscopy

    CERN Document Server

    Rodriguez-Ardila, A; Martins, L; Almeida, C Ramos; Riffel, R A; Riffel, R; Lira, P; Martin, O Gonzalez; Dametto, N Z; Flohic, H; Ho, L C; Ruschel-Dutra, D; Thanjavur, K; Colina, L; McDermid, R M; Perlman, E; Winge, C

    2016-01-01

    We present Gemini/GNIRS spectroscopy of the Seyfert 2 galaxy NGC 4388, with simultaneous coverage from 0.85 - 2.5 $\\mu$m. Several spatially-extended emission lines are detected for the first time, both in the obscured and unobscured portion of the optical narrow line region (NLR), allowing us to assess the combined effects of the central continuum source, outflowing gas and shocks generated by the radio jet on the central 280 pc gas. The HI and [FeII] lines allow us to map the extinction affecting the NLR. We found that the nuclear region is heavily obscured, with E(B-V) ~1.9 mag. To the NE of the nucleus and up to ~150 pc, the extinction remains large, ~1 mag or larger, consistent with the system of dust lanes seen in optical imaging. We derived position-velocity diagrams for the most prominent lines as well as for the stellar component. Only the molecular gas and the stellar component display a well-organized pattern consistent with disk rotation. Other emission lines are kinematically perturbed or show lit...

  5. Molecular structure (monomeric and dimeric) and hydrogen bonds in 5-benzyl 2-thiohydantoin studied by FT-IR and FT-Raman spectroscopy and DFT calculations

    Science.gov (United States)

    Deval, Vipin; Kumar, Amit; Gupta, Vineet; Sharma, Anamika; Gupta, Archana; Tandon, Poonam; Kunimoto, Ko-Ki

    2014-11-01

    In the present work the structural and spectral characteristics of 5-benzyl-2-thiohydantoin (5-BTH) have been studied by methods of infrared, Raman spectroscopy and quantum chemistry. Electrostatic potential surface, optimized geometry, harmonic vibrational frequencies, infrared intensities and activities of Raman scattering were calculated by density functional theory (DFT) employing B3LYP with complete relaxation in the potential energy surface using 6-311G++(d,p) basis set. Our results support the hydrogen bonding pattern proposed by reported crystalline structure. Stability of the molecule arising from hyperconjugative interactions, charge delocalization have been analyzed using natural bond orbital (NBO) analysis. The 13C nuclear magnetic resonance (NMR) chemical shifts of the molecule are calculated by the gauge independent atomic orbital (GIAO) method and compared with experimental results. UV-vis spectrum of the compound was recorded in methanol solvent. The TD-DFT calculations have been performed to explore the influence of electronic absorption spectra in the gas phase, as well as in solution environment using PCM and 6-311++G(d,p) basis set. In addition, the thermodynamic properties of the compound were calculated at different temperatures and corresponding relations between the properties and temperature were also studied.

  6. IR action spectroscopy shows competitive oxazolone and diketopiperazine formation in peptides depends on peptide length and identity of terminal residue in the departing fragment.

    Science.gov (United States)

    Morrison, L J; Chamot-Rooke, J; Wysocki, V H

    2014-05-01

    The interplay between the entropically and enthalpically favored products of peptide fragmentation is probed using a combined experimental and theoretical approach. These b2 ion products can take either an oxazolone or diketopiperazine structure. Cleavage after the second amide bond is often a favorable process because the products are small ring structures that are particularly stable. These structures are structurally characterized by action IRMPD spectroscopy and semi-quantified using gas-phase hydrogen-deuterium exchange. The formation of the oxazolone and diketopiperazine has been thought to be largely governed by the identity of the first two residues at the N-terminus of the peptide. We show here that the length of the precursor peptide and identity of the third residue play a significant role in the formation of the diketopiperazine structure in peptides containing an N-terminal asparagine residue. This is additionally the first instance showing an N-terminal residue with an amide side chain can promote formation of the diketopiperazine b2 ion structure.

  7. Temperature dependent kinetics of the OH/HO{sub 2}/O{sub 3} chain reaction by time-resolved IR laser absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Nizkorodov, S.A.; Harper, W.W.; Blackmon, B.W.; Nesbitt, D.J.

    2000-05-04

    This paper presents an extensive temperature dependent kinetic study of the catalytic HO{sub x} ozone cycle, (1) OH + O{sub 3} {r_arrow} HO{sub 2} + O{sub 2} and (2) HO{sub 2} + O{sub 3} {r_arrow} OH + 2 O{sub 2}, based on time-resolved, Doppler limited direct absorption spectroscopy of OH with a single mode ({Delta}{nu} = 0.0001 cm{sup {minus}1}) high-resolution infrared laser. The sum of the two chain rate constants, k{sub 1} + k{sub 2}, is measured over the 190--315 K temperature range and can be accurately described by an Arrhenius-type expression: k{sub 1} + k{sub 2} (cm{sup 3}/s) = 2.26(40) x 10{sup {minus}12} exp[{minus}976(50)/T]. These results are in excellent agreement with studies by Ravishankara et al. and Smith et al. but are significantly higher than the values currently accepted for atmospheric modeling. In addition, these studies also reflect the first such rate measurements to access the 190--230 K temperature range relevant to kinetic modeling of ozone chain loss in the lower stratosphere.

  8. Annotated Bibliography of EDGE2D Use

    International Nuclear Information System (INIS)

    This annotated bibliography is intended to help EDGE2D users, and particularly new users, find existing published literature that has used EDGE2D. Our idea is that a person can find existing studies which may relate to his intended use, as well as gain ideas about other possible applications by scanning the attached tables

  9. Port Adriano, 2D-Model Tests

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Andersen, Thomas Lykke; Jensen, Palle Meinert

    This report present the results of 2D physical model tests (length scale 1:50) carried out in a waveflume at Dept. of Civil Engineering, Aalborg University (AAU).......This report present the results of 2D physical model tests (length scale 1:50) carried out in a waveflume at Dept. of Civil Engineering, Aalborg University (AAU)....

  10. Annotated Bibliography of EDGE2D Use

    Energy Technology Data Exchange (ETDEWEB)

    J.D. Strachan and G. Corrigan

    2005-06-24

    This annotated bibliography is intended to help EDGE2D users, and particularly new users, find existing published literature that has used EDGE2D. Our idea is that a person can find existing studies which may relate to his intended use, as well as gain ideas about other possible applications by scanning the attached tables.

  11. Detect changes in lipid-related structure of brown- and yellow-seeded Brassica Carinata seed during rumen fermentation in relation to basic chemical profile using ATR-FT/IR molecular spectroscopy with chemometrics

    Science.gov (United States)

    Xin, Hangshu; Yu, Peiqiang

    2014-12-01

    In this experiment, brown- and yellow-seeded Brassica carinata were selected to use as a model to investigate whether there were any changes in lipid-related structure make-up (including CH3 and CH2 asymmetric and symmetric stretching bands ca. 3010-2765 cm-1, unsaturated lipid band ca. 3043-2987 cm-1 and carbonyl Cdbnd O ester band ca. 1789-1701 cm-1) of oilseed tissue during rumen in situ incubation using attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FT/IR). Correlations of lipid spectral characteristics with basic chemical profile and multivariate analyses for clarifying structural differences within lipid regions between two carinata seeds were also measured. The results showed that most spectral parameters in both carinata seeds were reduced as incubation time increased. However, the extent of changes in peak intensity of carbonyl Cdbnd O ester group of brown-seeded carinata was not in fully accordance with that of yellow-seeded carinata. Additionally, these lipid structure features were highly correlated with the concentrations of OM (positively), CP (positively), NDF (negatively) and EE (positively) in carinata seeds after 0, 12, 24 and 48 h of incubation. Based on the results from multivariate analyses, neither AHCA nor PCA could produce any distinctions in rumen residues between brown- and yellow-seeded carinata in spectra at lipid regions. It was concluded that besides for original feed samples, spectroscopic technique of ATR-FT/IR could also be used for rumen degradation residues in detecting changes in lipid-related molecular structure make-up. Further studies are needed to explore more details in lipid metabolism during ruminal fermentation with the combined consideration on both metabolic basis and molecular structural basis.

  12. Synthesis, structure and near-infrared luminescence of a new 2D praseodymium(Ⅲ) coordination polymer

    Institute of Scientific and Technical Information of China (English)

    LIU Guangxiang; ZHOU Hong; REN Xiaoming

    2011-01-01

    A novel coordination polymer,[Pr2(BIPA)3(H2O)2]·2H2O (1) (H2BIPA=5-bromoisophthalic acid),was prepared by hydrothermal synthesis and characterized by IR spectroscopy,elemental analysis and single-crystal X-ray diffraction.The crystal was of monoclinic system,space group C2/c,with a=1.98037(14),b=1.44189(14),c=2.15281(18) nm,β=95.220(2)°,V=6.1218(9) nm3,C24H17Br3O16Pr2,Mr=1082.93,De=2.350 g/cm3,F(000)=4096,μ=7.136 mm-1 and Z=8.The final R 1=0.0608 and wR2=0.1371 for 5624 observed reflections ((I)>2σ((I))).Complex 1 featured an interesting 2D layer containing {Pr2(CO2)3}n right-handed and left-handed helical chains.Furthermore,hydrogen bonds linked the adjacent 2D layers to form a 3D supramolecular framework.Moreover,the near-infrared luminescent properties of 1 were also investigated in the solid state.

  13. The c2d Spitzer spectroscopic survey of ices around low-mass young stellar objects II: CO2

    CERN Document Server

    Pontoppidan, Klaus M; Fraser, Helen J; van Dishoeck, Ewine F; Blake, Geoffrey A; Lahuis, Fred; Oberg, Karin I; Evans, Neal J; Salyk, Colette

    2007-01-01

    This paper presents Spitzer-IRS spectroscopy of the CO2 15.2 micron bending mode toward a sample of 50 embedded low-mass stars in nearby star-forming clouds, taken mostly from the ``Cores to Disks (c2d)'' Legacy program. The average abundance of solid CO2 relative to water in low-mass protostellar envelopes is 0.32 +/- 0.02, significantly higher than that found in quiescent molecular clouds and in massive star forming regions. It is found that a decomposition of all the observed CO2 bending mode profiles requires a minimum of five unique components. Roughly 2/3 of the CO2 ice is found in a water-rich environment, while most of the remaining 1/3 is found in a CO environment. Ground-based observations of solid CO toward a large subset of the c2d sample are used to further constrain the CO2:CO component and suggest a model in which low-density clouds form the CO2:H2O component and higher density clouds form the CO2:CO ice during and after the freeze-out of gas-phase CO. It is suggested that the subsequent evolut...

  14. 2D materials for nanophotonic devices

    Science.gov (United States)

    Xu, Renjing; Yang, Jiong; Zhang, Shuang; Pei, Jiajie; Lu, Yuerui

    2015-12-01

    Two-dimensional (2D) materials have become very important building blocks for electronic, photonic, and phononic devices. The 2D material family has four key members, including the metallic graphene, transition metal dichalcogenide (TMD) layered semiconductors, semiconducting black phosphorous, and the insulating h-BN. Owing to the strong quantum confinements and defect-free surfaces, these atomically thin layers have offered us perfect platforms to investigate the interactions among photons, electrons and phonons. The unique interactions in these 2D materials are very important for both scientific research and application engineering. In this talk, I would like to briefly summarize and highlight the key findings, opportunities and challenges in this field. Next, I will introduce/highlight our recent achievements. We demonstrated atomically thin micro-lens and gratings using 2D MoS2, which is the thinnest optical component around the world. These devices are based on our discovery that the elastic light-matter interactions in highindex 2D materials is very strong. Also, I would like to introduce a new two-dimensional material phosphorene. Phosphorene has strongly anisotropic optical response, which creates 1D excitons in a 2D system. The strong confinement in phosphorene also enables the ultra-high trion (charged exciton) binding energies, which have been successfully measured in our experiments. Finally, I will briefly talk about the potential applications of 2D materials in energy harvesting.

  15. 2D supergravity in p+1 dimensions

    OpenAIRE

    Gustafsson, H.; Lindstrom, U.

    1998-01-01

    We describe new $N$-extended 2D supergravities on a $(p+1)$-dimensional (bosonic) space. The fundamental objects are moving frame densities that equip each $(p+1)$-dimensional point with a 2D ``tangent space''. The theory is presented in a $[p+1, 2]$ superspace. For the special case of $p=1$ we recover the 2D supergravities in an unusual form. The formalism has been developed with applications to the string-parton picture of $D$-branes at strong coupling in mind.

  16. 2D Barcode for DNA Encoding

    OpenAIRE

    Elena Purcaru; Cristian Toma

    2012-01-01

    The paper presents a solution for endcoding/decoding DNA information in 2D barcodes. First part focuses on the existing techniques and symbologies in 2D barcodes field. The 2D barcode PDF417 is presented as starting point. The adaptations and optimizations on PDF417 and on DataMatrix lead to the solution – DNA2DBC – DeoxyriboNucleic Acid Two Dimensional Barcode. The second part shows the DNA2DBC encoding/decoding process step by step. In conclusions are enumerated the most important features ...

  17. Correlated Electron Phenomena in 2D Materials

    Science.gov (United States)

    Lambert, Joseph G.

    In this thesis, I present experimental results on coherent electron phenomena in layered two-dimensional materials: single layer graphene and van der Waals coupled 2D TiSe2. Graphene is a two-dimensional single-atom thick sheet of carbon atoms first derived from bulk graphite by the mechanical exfoliation technique in 2004. Low-energy charge carriers in graphene behave like massless Dirac fermions, and their density can be easily tuned between electron-rich and hole-rich quasiparticles with electrostatic gating techniques. The sharp interfaces between regions of different carrier densities form barriers with selective transmission, making them behave as partially reflecting mirrors. When two of these interfaces are set at a separation distance within the phase coherence length of the carriers, they form an electronic version of a Fabry-Perot cavity. I present measurements and analysis of multiple Fabry-Perot modes in graphene with parallel electrodes spaced a few hundred nanometers apart. Transition metal dichalcogenide (TMD) TiSe2 is part of the family of materials that coined the term "materials beyond graphene". It contains van der Waals coupled trilayer stacks of Se-Ti-Se. Many TMD materials exhibit a host of interesting correlated electronic phases. In particular, TiSe2 exhibits chiral charge density waves (CDW) below TCDW ˜ 200 K. Upon doping with copper, the CDW state gets suppressed with Cu concentration, and CuxTiSe2 becomes superconducting with critical temperature of T c = 4.15 K. There is still much debate over the mechanisms governing the coexistence of the two correlated electronic phases---CDW and superconductivity. I will present some of the first conductance spectroscopy measurements of proximity coupled superconductor-CDW systems. Measurements reveal a proximity-induced critical current at the Nb-TiSe2 interfaces, suggesting pair correlations in the pure TiSe2. The results indicate that superconducting order is present concurrently with CDW in

  18. Detect changes in protein structure of carinata meal during rumen fermentation in relation to basic chemical profile and comparison with canola meal using ATR-FT/IR molecular spectroscopy with chemometrics

    Science.gov (United States)

    Xin, Hangshu; Yu, Peiqiang

    2013-08-01

    As far as we know, no study has been carried out on whether protein structure changes in the feed during rumen fermentation from other research team. This study was conducted to characterize protein structure spectral changes in carinata meal during ruminal fermentation using Fourier transform infrared spectroscopy (FT/IR) technique with ATR. The objectives were to find out whether (1) protein internal structure (in terms of protein amide profile and protein secondary structure profile) changed after in situ ruminal fermentation at 0, 12, 24 and 48 h in carinata meal and conventional canola meal was used as a reference; (2) there was any correlation between protein spectral parameters and basic chemical profile in in situ rumen residue samples; and (3) the protein structural chemical make-up of carinata meal differed from canola meal during 48 h rumen incubation. The results showed that protein structure features in both carinata meal and canola meal were altered as incubation time increased (P meal was not distinguished from those from canola meal, suggesting some relationship in structural make-up exhibited between them within protein region during 48 h rumen fermentation. Further studies are still needed to investigate detailed information on structural changes in protein of various feedstuffs in order to fully and deeply understand protein degradation during rumen fermentation on both metabolic basis and molecular biological basis.

  19. Infrared spectra of U.S. automobile original finishes (1998-2000). IX. identification of bismuth oxychloride and silver/white mica pearlescent pigments using extended range FT-IR spectroscopy, XRF spectrometry, and SEM/EDS analysis.

    Science.gov (United States)

    Suzuki, Edward M

    2014-09-01

    Bismuth oxychloride (BiOCl) was the first viable synthetic pearl pigment developed 50 years ago. It was only used for a limited time period in automotive paint (model years 1998-2000), serving to produce luster for a single Chrysler black metallic color. Identification of this pigment in an unknown automotive paint can thus facilitate determination of the vehicle of origin. Bismuth oxychloride imparts effects similar to those produced by silver/white mica pearlescent pigments, and such a pigment was used together with bismuth oxychloride in at least one original equipment manufacturer (OEM) basecoat. Silver/white micas are now used primarily in white pearl tricoat systems. This article describes the identification of bismuth oxychloride and silver/white mica pearlescent pigments in automotive finishes using FT-IR spectroscopy, X-ray fluorescence (XRF) spectrometry, and SEM/EDS analysis. Data for some cadmium pigments, which were used in automotive paint several decades ago, are also presented as they produce infrared absorptions similar to that of bismuth oxychloride. PMID:24646090

  20. Investigation of the Poisoning Mechanism of Lead on the CeO2-WO3 Catalyst for the NH3-SCR Reaction via in Situ IR and Raman Spectroscopy Measurement.

    Science.gov (United States)

    Peng, Yue; Si, Wenzhe; Li, Xiang; Chen, Jianjun; Li, Junhua; Crittenden, John; Hao, Jiming

    2016-09-01

    The in situ IR and Raman spectroscopy measurements were conducted to investigate lead poisoning on the CeO2-WO3 catalysts. The deactivation mechanisms were studied with respect to the changes of surface acidity, redox property, nitrate/nitrite adsorption behaviors, and key active sites (note that the results of structure-activity relationship of CeO2-WO3 were based on our previous research). (1) Lewis acid sites originated from CeO2 and crystalline WO3, whereas Brønsted acid sites originated from Ce2(WO4)3. The poisoned catalysts exhibited a lower surface acidity than the fresh catalysts: the number of acid sites decreased, and their thermal stability weakened. (2) The reducibility of catalysts and the amount of active oxygen exhibited a smaller influence after poisoning because lead preferred to bond with surface WOx species rather than CeO2. (3) The quantity of active nitrate species decreased due to the lead coverage on the catalyst and the partial bridged-nitrate species induced by lead exhibited a low degree of activity at 200 °C. (4) Crystalline WO3 and Ce2(WO4)3 originated from the transformation of polytungstate sites. These sites were the key active sites during the SCR process. The formation temperatures of polytungstate on the poisoned catalysts were higher than those on the fresh catalysts. PMID:27480109

  1. Investigation of the Poisoning Mechanism of Lead on the CeO2-WO3 Catalyst for the NH3-SCR Reaction via in Situ IR and Raman Spectroscopy Measurement.

    Science.gov (United States)

    Peng, Yue; Si, Wenzhe; Li, Xiang; Chen, Jianjun; Li, Junhua; Crittenden, John; Hao, Jiming

    2016-09-01

    The in situ IR and Raman spectroscopy measurements were conducted to investigate lead poisoning on the CeO2-WO3 catalysts. The deactivation mechanisms were studied with respect to the changes of surface acidity, redox property, nitrate/nitrite adsorption behaviors, and key active sites (note that the results of structure-activity relationship of CeO2-WO3 were based on our previous research). (1) Lewis acid sites originated from CeO2 and crystalline WO3, whereas Brønsted acid sites originated from Ce2(WO4)3. The poisoned catalysts exhibited a lower surface acidity than the fresh catalysts: the number of acid sites decreased, and their thermal stability weakened. (2) The reducibility of catalysts and the amount of active oxygen exhibited a smaller influence after poisoning because lead preferred to bond with surface WOx species rather than CeO2. (3) The quantity of active nitrate species decreased due to the lead coverage on the catalyst and the partial bridged-nitrate species induced by lead exhibited a low degree of activity at 200 °C. (4) Crystalline WO3 and Ce2(WO4)3 originated from the transformation of polytungstate sites. These sites were the key active sites during the SCR process. The formation temperatures of polytungstate on the poisoned catalysts were higher than those on the fresh catalysts.

  2. Slow positron beam experiment using 2D-ACAR

    International Nuclear Information System (INIS)

    We developed a γ-incident position detector using the position sensitive photomultiplier R3941. The equipment is set up five meters apart from the sample and used for the experiment by the continuous spectrum positron. If the sample with width 2 mm were measured, the resolving power became about 1.2 m rad and the average coincidence counter coefficiency about 50 cps by radiation source 1GBq 22Na. A positronium emission spectroscopy is explained as the experimental example of a combination of low-energy position beam and 2D-ACAR. (S.Y.)

  3. Computation of 2-D spectra assisted by compressed sampling

    CERN Document Server

    Almeida, J; Plenio, M B

    2012-01-01

    The computation of scientific data can be very time consuming even if they are ultimately determined by a small number of parameters. The principle of compressed sampling suggests that we can achieve a considerable decrease in the computation time by avoiding the need to sample the full data set. We demonstrate the usefulness of this approach at the hand of 2-D spectra in the context of ultra-fast non-linear spectroscopy of biological systems where numerical calculations are highly challenging due to the considerable computational effort involved in obtaining individual data points.

  4. 2D Saturable Absorbers for Fibre Lasers

    Directory of Open Access Journals (Sweden)

    Robert I. Woodward

    2015-11-01

    Full Text Available Two-dimensional (2D nanomaterials are an emergent and promising platform for future photonic and optoelectronic applications. Here, we review recent progress demonstrating the application of 2D nanomaterials as versatile, wideband saturable absorbers for Q-switching and mode-locking fibre lasers. We focus specifically on the family of few-layer transition metal dichalcogenides, including MoS2, MoSe2 and WS2.

  5. Beltrami States in 2D Electron Magnetohydrodynamics

    OpenAIRE

    Shivamoggi, B. K.

    2015-01-01

    In this paper, the Hamiltonian formulations along with the Poisson brackets for two-dimensional (2D) electron magnetohydrodynamics (EMHD) flows are developed. These formulations are used to deduce the Beltrami states for 2D EMHD flows. In the massless electron limit, the EMHD Beltrami states reduce to the force-free states, though there is no force-free Beltrami state in the general EMHD case.

  6. Glitter in a 2D monolayer.

    Science.gov (United States)

    Yang, Li-Ming; Dornfeld, Matthew; Frauenheim, Thomas; Ganz, Eric

    2015-10-21

    We predict a highly stable and robust atomically thin gold monolayer with a hexagonal close packed lattice stabilized by metallic bonding with contributions from strong relativistic effects and aurophilic interactions. We have shown that the framework of the Au monolayer can survive 10 ps MD annealing simulations up to 1400 K. The framework is also able to survive large motions out of the plane. Due to the smaller number of bonds per atom in the 2D layer compared to the 3D bulk we observe significantly enhanced energy per bond (0.94 vs. 0.52 eV per bond). This is similar to the increase in bond strength going from 3D diamond to 2D graphene. It is a non-magnetic metal, and was found to be the global minima in the 2D space. Phonon dispersion calculations demonstrate high kinetic stability with no negative modes. This 2D gold monolayer corresponds to the top monolayer of the bulk Au(111) face-centered cubic lattice. The close-packed lattice maximizes the aurophilic interactions. We find that the electrons are completely delocalized in the plane and behave as 2D nearly free electron gas. We hope that the present work can inspire the experimental fabrication of novel free standing 2D metal systems.

  7. 2d index and surface operators

    Science.gov (United States)

    Gadde, Abhijit; Gukov, Sergei

    2014-03-01

    In this paper we compute the superconformal index of 2d (2, 2) supersymmetric gauge theories. The 2d superconformal index, a.k.a. flavored elliptic genus, is computed by a unitary matrix integral much like the matrix integral that computes the 4d superconformal index. We compute the 2d index explicitly for a number of examples. In the case of abelian gauge theories we see that the index is invariant under flop transition and under CY-LG correspondence. The index also provides a powerful check of the Seiberg-type duality for non-abelian gauge theories discovered by Hori and Tong. In the later half of the paper, we study half-BPS surface operators in = 2 super-conformal gauge theories. They are engineered by coupling the 2d (2, 2) supersymmetric gauge theory living on the support of the surface operator to the 4d = 2 theory, so that different realizations of the same surface operator with a given Levi type are related by a 2d analogue of the Seiberg duality. The index of this coupled system is computed by using the tools developed in the first half of the paper. The superconformal index in the presence of surface defect is expected to be invariant under generalized S-duality. We demonstrate that it is indeed the case. In doing so the Seiberg-type duality of the 2d theory plays an important role.

  8. 2-D DOA Estimation Based on 2D-MUSIC%基于2D-MUSIC算法的DOA估计

    Institute of Scientific and Technical Information of China (English)

    康亚芳; 王静; 张清泉; 行小帅

    2014-01-01

    This paper discussed the performance of classical two-dimensional DOA estimation with 2D-MUSIC, based on the mathematical model of planar array and 2D-MUSIC DOA estimation, Taking uniform planar array for example, comput-er simulation experiment was carried for the effect of three kinds of different parameters on 2-D DOA estimation, and the simulation results were analyzed. And also verification test about the corresponding algorithm performance under the differ-ent parameters was discussed.%利用经典的2D-MUSIC算法对二维阵列的DOA估计进行了研究,在平面阵列数学模型以及2D-MUSIC算法的DOA估计模型基础上,以均匀平面阵列为例,对3种不同参数的DOA估计进行了计算机仿真,分析了仿真结果。得出了在不同参数变化趋势下DOA估计的相应变化情况。

  9. Testing a new analytical approach for determination of vibrational transition moment directions in low symmetry planar molecules: 1-D- and 2-D-naphthalene.

    Science.gov (United States)

    Rogojerov, Marin; Keresztury, Gábor; Kamenova-Nacheva, Mariana; Sundius, Tom

    2012-12-01

    A new analytical approach for improving the precision in determination of vibrational transition moment directions of low symmetry molecules (lacking orthogonal axes) is discussed in this paper. The target molecules are partially uniaxially oriented in nematic liquid crystalline solvent and are studied by IR absorption spectroscopy using polarized light. The fundamental problem addressed is that IR linear dichroism measurements of low symmetry molecules alone cannot provide sufficient information on molecular orientation and transition moment directions. It is shown that computational prediction of these quantities can supply relevant complementary data, helping to reveal the hidden information content and achieve a more meaningful and more precise interpretation of the measured dichroic ratios. The combined experimental and theoretical/computational method proposed by us recently for determination of the average orientation of molecules with C(s) symmetry has now been replaced by a more precise analytical approach. The new method introduced and discussed in full detail here uses a mathematically evaluated angle between two vibrational transition moment vectors as a reference. The discussion also deals with error analysis and estimation of uncertainties of the orientational parameters. The proposed procedure has been tested in an analysis of the infrared linear dichroism (IR-LD) spectra of 1-D- and 2-D-naphthalene complemented with DFT calculations using the scaled quantum mechanical force field (SQM FF) method. PMID:22981590

  10. Construction of a 2D Co(II) Coordination Polymer with (4,4)-Connected Topology: Synthesis, Crystal Structure, and Surface Photo-electric Property

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jiaming [Qinzhou Univ., Qinzhou (China)

    2014-04-15

    A 2D grid-like (4, 4)-connected topology coordination polymer, [Co(BTA){sub 2}(H{sub 2}O){sub 2}]{sub n}, where HBTA = 2-(1H-benzotriazol-1-yl)acetic acid, has been synthesized by hydrothermal method and characterized by single crystal X-ray diffraction, IR spectroscopy, elemental analysis and surface photovoltage spectroscopy (SPS). X-ray diffraction analyses indicated that displays octahedral metal centers with secondary building units (SBUs) [Co(BTA){sub 2}(H{sub 2}O){sub 2}] bridged by the BTA. ligands. In the crystal, the 2D supramolecular architecture is further supported by O-H···O, O-H···N, C-H···O hydrogen bonds and π··π stacking interactions. The SPS of polymer 1 indicates that there are positive response bands in the range of 300.600 nm showing photo-electric conversion properties. There are good relationships between SPS and UV-Vis spectra.

  11. Determinação quantitativa da concentração de silicone em antiespumantes por espectroscopia FT-IR / ATR e calibração multivariada Quantitative determination of silicone in antifoaming products by FT-IR / ATR spectroscopy and multivariate calibration

    Directory of Open Access Journals (Sweden)

    Marcelo H. F. Garcia

    2004-12-01

    Full Text Available Neste trabalho apresentamos uma alternativa para a dosagem do teor de silicone (polidimetilsiloxano em antiespumantes por meio da técnica de espectroscopia no infravermelho com transformada de Fourier (FT-IR, com a utilização do acessório de reflectância total atenuada (ATR. Os espectros foram registrados na faixa espectral de 2500 a 780 cm-1, com resolução de 4 cm-1 e 128 varreduras. A calibração de um modelo linear por meio da utilização do método de mínimos quadrados parciais (PLS aplicado aos espectros foi capaz de determinar satisfatoriamente a concentração de silicone nas amostras. Este método é de extrema importância para indústrias produtoras de antiespumantes siliconados, uma vez que o desempenho de tais produtos geralmente é avaliado em função da viscosidade dos mesmos. Muitas vezes no processo de fabricação de tais produtos ocorre uma homogeneização incompleta do silicone no solvente, o que leva a resultados de viscosidade que não são representativos das amostras analisadas. A determinação da concentração do teor de silicone é uma importante ferramenta para o Controle Estatístico de Processo (CEP, pois evita o desperdício de matérias-primas empregadas na fabricação dos antiespumantes.This work presents an alternative method to determine the concentration of silicone (polydimethylsiloxane in antifoaming products using Fourier Transformed Infrared Spectroscopy (FT-IR with the attenuated total reflectance (ATR accessory. The spectra were recorded in the range from 2500 to 780 cm-1, with a resolution of 4 cm-1 and 128 scans. With calibration of a linear model using PLS regression method applied to spectral data we were able to determine the silicone concentration in the samples. This method may be useful for antifoaming producers since the performance of such products generally is evaluated as a function of their viscosity. Moreover, during manufacturing an incomplete homogenization of silicone in the

  12. 2d Index and Surface operators

    CERN Document Server

    Gadde, Abhijit

    2013-01-01

    In this paper we compute the superconformal index of 2d (2,2) supersymmetric gauge theories. The 2d superconformal index, a.k.a. flavored elliptic genus, is computed by a unitary matrix integral much like the matrix integral that computes 4d superconformal index. We compute the 2d index explicitly for a number of examples. In the case of abelian gauge theories we see that the index is invariant under flop transition and CY-LG correspondence. The index also provides a powerful check of the Seiberg-type duality for non-abelian gauge theories discovered by Hori and Tong. In the later half of the paper, we study half-BPS surface operators in N=2 superconformal gauge theories. They are engineered by coupling the 2d (2,2) supersymmetric gauge theory living on the support of the surface operator to the 4d N=2 theory, so that different realizations of the same surface operator with a given Levi type are related by a 2d analogue of the Seiberg duality. The index of this coupled system is computed by using the tools de...

  13. Optical modulators with 2D layered materials

    Science.gov (United States)

    Sun, Zhipei; Martinez, Amos; Wang, Feng

    2016-04-01

    Light modulation is an essential operation in photonics and optoelectronics. With existing and emerging technologies increasingly demanding compact, efficient, fast and broadband optical modulators, high-performance light modulation solutions are becoming indispensable. The recent realization that 2D layered materials could modulate light with superior performance has prompted intense research and significant advances, paving the way for realistic applications. In this Review, we cover the state of the art of optical modulators based on 2D materials, including graphene, transition metal dichalcogenides and black phosphorus. We discuss recent advances employing hybrid structures, such as 2D heterostructures, plasmonic structures, and silicon and fibre integrated structures. We also take a look at the future perspectives and discuss the potential of yet relatively unexplored mechanisms, such as magneto-optic and acousto-optic modulation.

  14. Automatic Contour Extraction from 2D Image

    Directory of Open Access Journals (Sweden)

    Panagiotis GIOANNIS

    2011-03-01

    Full Text Available Aim: To develop a method for automatic contour extraction from a 2D image. Material and Method: The method is divided in two basic parts where the user initially chooses the starting point and the threshold. Finally the method is applied to computed tomography of bone images. Results: An interesting method is developed which can lead to a successful boundary extraction of 2D images. Specifically data extracted from a computed tomography images can be used for 2D bone reconstruction. Conclusions: We believe that such an algorithm or part of it can be applied on several other applications for shape feature extraction in medical image analysis and generally at computer graphics.

  15. 2D microwave imaging reflectometer electronics

    Energy Technology Data Exchange (ETDEWEB)

    Spear, A. G.; Domier, C. W., E-mail: cwdomier@ucdavis.edu; Hu, X.; Muscatello, C. M.; Ren, X.; Luhmann, N. C. [Electrical and Computer Engineering, University of California, Davis, California 95616 (United States); Tobias, B. J. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

    2014-11-15

    A 2D microwave imaging reflectometer system has been developed to visualize electron density fluctuations on the DIII-D tokamak. Simultaneously illuminated at four probe frequencies, large aperture optics image reflections from four density-dependent cutoff surfaces in the plasma over an extended region of the DIII-D plasma. Localized density fluctuations in the vicinity of the plasma cutoff surfaces modulate the plasma reflections, yielding a 2D image of electron density fluctuations. Details are presented of the receiver down conversion electronics that generate the in-phase (I) and quadrature (Q) reflectometer signals from which 2D density fluctuation data are obtained. Also presented are details on the control system and backplane used to manage the electronics as well as an introduction to the computer based control program.

  16. Simulating two-dimensional infrared-Raman and Raman spectroscopies for intermolecular and intramolecular modes of liquid water.

    Science.gov (United States)

    Ito, Hironobu; Tanimura, Yoshitaka

    2016-02-21

    Full classical molecular dynamics (MD) simulations of two-dimensional (2D) infrared-Raman and 2D Raman spectroscopies of liquid water were carried out to elucidate a mode-mode coupling mechanism using a polarizable water model for intermolecular and intramolecular vibrational spectroscopy (POLI2VS). This model is capable of describing both infrared and Raman spectra. Second-order response functions, which consist of one molecular polarizability and two molecular dipole moments for 2D IR-Raman and three molecular polarizabilities for 2D Raman spectroscopies, were calculated using an equilibrium-non-equilibrium hybrid MD approach. The obtained signals were analyzed using a multi-mode Brownian oscillator (BO) model with nonlinear system-bath interactions representing the intramolecular OH stretching, intramolecular HOH bending, hydrogen bonded (HB)-intermolecular librational motion and HB-intermolecular vibrational (translational) motion of liquid water. This model was applied through use of hierarchal Fokker-Planck equations. The qualitative features of the peak profiles in the 2D spectra obtained from the MD simulations are accurately reproduced with the BO model. This indicates that this model captures the essential features of the intermolecular and intramolecular motion. We elucidate the mechanisms governing the 2D signal profiles involving anharmonic mode-mode coupling, the nonlinearities of the polarizability and dipole moment, and the vibrational dephasing processes of liquid water even in the case that the 2D spectral peaks obtained from the MD simulation overlap or are unclear. The mode coupling peaks caused by electrical anharmonic coupling (EAHC) and mechanical anharmonic coupling (MAHC) are observed in all of the 2D spectra. We find that the strength of the MAHC between the OH-stretching and HB-intermolecular vibrational modes is comparable to that between the OH-stretching and HOH bending modes. Moreover, we find that this OH-stretching and HB

  17. Infrared Spectroscopy with Visible Light

    CERN Document Server

    Kalashnikov, Dmitry A; Kulik, Sergei P; Krivitsky, Leonid A

    2015-01-01

    Spectral measurements in the infrared (IR) optical range provide unique fingerprints of materials which are useful for material analysis, environmental sensing, and health diagnostics. Current IR spectroscopy techniques require the use of optical equipment suited for operation in the IR range, which faces challenges of inferior performance and high cost. Here we develop a spectroscopy technique, which allows spectral measurements in the IR range using visible spectral range components. The technique is based on nonlinear interference of infrared and visible photons, produced via Spontaneous Parametric Down Conversion (SPDC). The intensity interference pattern for a visible photon depends on the phase of an IR photon, which travels through the media. This allows determining properties of the media in the IR range from the measurements of visible photons. The technique can substitute and/or complement conventional IR spectroscopy techniques, as it uses well-developed optical components for the visible range.

  18. Growth of 2D black phosphorus film from chemical vapor deposition

    Science.gov (United States)

    Smith, Joshua B.; Hagaman, Daniel; Ji, Hai-Feng

    2016-05-01

    Phosphorene, a novel 2D material isolated from bulk black phosphorus (BP), is an intrinsic p-type material with a variable bandgap for a variety of applications. However, these applications are limited by the inability to isolate large films of phosphorene. Here we present an in situ chemical vapor deposition type approach that demonstrates progress towards growth of large area 2D BP with average areas >3 μm2 and thicknesses representing samples around four layers and thicker samples with average areas >100 μm2. Transmission electron microscopy and Raman spectroscopy have confirmed successful growth of 2D BP from red phosphorus.

  19. Growth of 2D black phosphorus film from chemical vapor deposition.

    Science.gov (United States)

    Smith, Joshua B; Hagaman, Daniel; Ji, Hai-Feng

    2016-05-27

    Phosphorene, a novel 2D material isolated from bulk black phosphorus (BP), is an intrinsic p-type material with a variable bandgap for a variety of applications. However, these applications are limited by the inability to isolate large films of phosphorene. Here we present an in situ chemical vapor deposition type approach that demonstrates progress towards growth of large area 2D BP with average areas >3 μm(2) and thicknesses representing samples around four layers and thicker samples with average areas >100 μm(2). Transmission electron microscopy and Raman spectroscopy have confirmed successful growth of 2D BP from red phosphorus. PMID:27087456

  20. Complex Hydrocarbon Chemistry in Interstellar and Solar System Ices Revealed: A Combined Infrared Spectroscopy and Reflectron Time-of-flight Mass Spectrometry Analysis of Ethane (C2H6) and D6-Ethane (C2D6) Ices Exposed to Ionizing Radiation

    Science.gov (United States)

    Abplanalp, Matthew J.; Kaiser, Ralf I.

    2016-08-01

    The irradiation of pure ethane (C2H6/C2D6) ices at 5.5 K, under ultrahigh vacuum conditions was conducted to investigate the formation of complex hydrocarbons via interaction with energetic electrons simulating the secondary electrons produced in the track of galactic cosmic rays. The chemical modifications of the ices were monitored in situ using Fourier transform infrared spectroscopy (FTIR) and during temperature-programmed desorption via mass spectrometry exploiting a quadrupole mass spectrometer with electron impact ionization (EI-QMS) as well as a reflectron time-of-flight mass spectrometer coupled to a photoionization source (PI-ReTOF-MS). FTIR confirmed previous ethane studies by detecting six molecules: methane (CH4), acetylene (C2H2), ethylene (C2H4), the ethyl radical (C2H5), 1-butene (C4H8), and n-butane (C4H10). However, the TPD phase, along with EI-QMS, and most importantly, PI-ReTOF-MS, revealed the formation of at least 23 hydrocarbons, many for the first time in ethane ice, which can be arranged in four groups with an increasing carbon-to-hydrogen ratio: C n H2n+2 (n = 3, 4, 6, 8, 10), C n H2n (n = 3-10), {{{C}}}n{{{H}}}2n-2 (n = 3-10), and {{{C}}}n{{{H}}}2n-4 (n = 4-6). The processing of simple ethane ices is relevant to the hydrocarbon chemistry in the interstellar medium, as ethane has been shown to be a major product of methane, as well as in the outer solar system. These data reveal that the processing of ethane ices can synthesize several key hydrocarbons such as C3H4 and C4H6 isomers, which ha­ve been found to synthesize polycyclic aromatic hydrocarbons like indene (C9H8) and naphtha­lene (C10H8) in the ISM and in hydrocarbon-rich atmospheres of planets and their moons such as Titan.

  1. Horns Rev II, 2-D Model Tests

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Frigaard, Peter

    This report present the results of 2D physical model tests carried out in the shallow wave flume at Dept. of Civil Engineering, Aalborg University (AAU), on behalf of Energy E2 A/S part of DONG Energy A/S, Denmark. The objective of the tests was: to investigate the combined influence of the pile...

  2. 2D PIM Simulation Based on COMSOL

    DEFF Research Database (Denmark)

    Wang, Xinbo; Cui, Wanzhao; Wang, Jingyu;

    2011-01-01

    Passive intermodulation (PIM) is a problematic type of nonlinear distortion en- countered in many communication systems. To analyze the PIM distortion resulting from ma- terial nonlinearity, a 2D PIM simulation method based on COMSOL is proposed in this paper. As an example, a rectangular waveguide...

  3. Baby universes in 2d quantum gravity

    OpenAIRE

    Ambjorn, J.; S. Jain; G. Thorleifsson

    1993-01-01

    We investigate the fractal structure of $2d$ quantum gravity, both for pure gravity and for gravity coupled to multiple gaussian fields and for gravity coupled to Ising spins. The roughness of the surfaces is described in terms of baby universes and using numerical simulations we measure their distribution which is related to the string susceptibility exponent $\\g_{string}$.

  4. Hydrogen intercalation under graphene on Ir(111)

    Science.gov (United States)

    Grånäs, Elin; Gerber, Timm; Schröder, Ulrike A.; Schulte, Karina; Andersen, Jesper N.; Michely, Thomas; Knudsen, Jan

    2016-09-01

    Using high resolution X-ray photoelectron spectroscopy and scanning tunneling microscopy we study the intercalation of hydrogen under graphene/Ir(111). The hydrogen intercalated graphene is characterized by a component in C 1s that is shifted -0.10 to -0.18 eV with respect to pristine graphene and a component in Ir 4f at 60.54 eV. The position of this Ir 4f component is identical to that of the Ir(111) surface layer with hydrogen atoms adsorbed, indicating that the atomic hydrogen adsorption site on bare Ir(111) and beneath graphene is the same. Based on co-existence of fully- and non-intercalated graphene, and the inability to intercalate a closed graphene film covering the entire Ir(111) surface, we conclude that hydrogen dissociatively adsorbs at bare Ir(111) patches, and subsequently diffuses rapidly under graphene. A likely entry point for the intercalating hydrogen atoms is identified to be where graphene crosses an underlying Ir(111) step.

  5. Magnetic field decoupling and 3D-2D crossover in Nb/Cu multilayers

    DEFF Research Database (Denmark)

    Krasnov, V.M.; Kovalev, A.E.; Oboznov, V.A.;

    1996-01-01

    Transport properties of Nb/Cu multilayers were measured along and across layers. Ir is shown that not only the temperature but also the magnetic field parallel to layers can effectively decouple layers and cause the three-to-two-dimensional (3D-2D) crossover. As a consequence of the 3D-2D crossover...... magnetic field and by the multiply branched I-V curves caused by flux-flow of Josephson vortices in the stacked superconductor-normal-metal-superconductor junctions composing the multilayer. By measurements across layers the ''breaking field'' at which the proximity induced superconductivity in the normal...

  6. Fabrication of 2D and 3D dendritic nanoarchitectures of CdS

    Institute of Scientific and Technical Information of China (English)

    GU Li

    2008-01-01

    The controlled preparation of two-dimensional (2D) and three-dimensional (3D) dendritic nanostructures of CdS was reported. 2D dendritic patterns are obtained through the self-assembly of nanoparticles under the entropy-driven force. 3D dendritic needle-like nanocrystals are prepared through an aqueous solution synthesis regulated by oleic acid molecules. Their growth mechanism is presumed to be the selective binding of OA molecules onto growing crystal planes. Techniques such as SEM, TEM, XRD, and FT-IR were employed to characterize the morphologies and structures of the obtained products.

  7. IR Spectroscopic signs of malignant neoplasms in the thyroid gland

    Science.gov (United States)

    Tolstorozhev, G. B.; Skornyakov, I. V.; Butra, V. A.

    2012-03-01

    We use Fourier transform IR spectroscopy to study thyroid tumor tissues which were removed during surgery. The IR spectra of the tissues with pathological foci are compared with data from histologic examination. In the region of N-H, C-H, and C = O stretching vibrations, the IR spectra of the tissues for thyroid cancer are different from the IR spectra of tissues without malignant formations. We identify the spectral signs of thyroid cancer. We show that IR analysis is promising for identification of thyroid pathology at the molecular level.

  8. Detectors with Improved Near-to-Mid IR Performance and Reduced Cooling Requirements Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This STTR Phase I proposal addresses a NASA need for improved near-to-mid IR detectors for imaging and spectroscopy. High performance IR detectors with cutoff...

  9. Application of 2D Non-Graphene Materials and 2D Oxide Nanostructures for Biosensing Technology.

    Science.gov (United States)

    Shavanova, Kateryna; Bakakina, Yulia; Burkova, Inna; Shtepliuk, Ivan; Viter, Roman; Ubelis, Arnolds; Beni, Valerio; Starodub, Nickolaj; Yakimova, Rositsa; Khranovskyy, Volodymyr

    2016-02-06

    The discovery of graphene and its unique properties has inspired researchers to try to invent other two-dimensional (2D) materials. After considerable research effort, a distinct "beyond graphene" domain has been established, comprising the library of non-graphene 2D materials. It is significant that some 2D non-graphene materials possess solid advantages over their predecessor, such as having a direct band gap, and therefore are highly promising for a number of applications. These applications are not limited to nano- and opto-electronics, but have a strong potential in biosensing technologies, as one example. However, since most of the 2D non-graphene materials have been newly discovered, most of the research efforts are concentrated on material synthesis and the investigation of the properties of the material. Applications of 2D non-graphene materials are still at the embryonic stage, and the integration of 2D non-graphene materials into devices is scarcely reported. However, in recent years, numerous reports have blossomed about 2D material-based biosensors, evidencing the growing potential of 2D non-graphene materials for biosensing applications. This review highlights the recent progress in research on the potential of using 2D non-graphene materials and similar oxide nanostructures for different types of biosensors (optical and electrochemical). A wide range of biological targets, such as glucose, dopamine, cortisol, DNA, IgG, bisphenol, ascorbic acid, cytochrome and estradiol, has been reported to be successfully detected by biosensors with transducers made of 2D non-graphene materials.

  10. Vibrational ladder-climbing in surface-enhanced, ultrafast infrared spectroscopy.

    Science.gov (United States)

    Kraack, Jan Philip; Hamm, Peter

    2016-06-28

    In a recent work (J. Phys. Chem. C 2016, 120, 3350-3359), we have introduced the concept of surface-enhanced, two-dimensional attenuated total reflectance (2D ATR IR) spectroscopy with modest enhancement factors (450), which allows for multi-quantum IR excitation of adsorbed molecules, a process known as "vibrational ladder-climbing", even for weakly absorbing (ε < 200 M(-1) cm(-1)) nitrile IR labels. We show that it is possible to deposit up to four quanta of vibrational energy in the respective functional group. Based on these results, optical near-fields of plasmonic nanostructures may pave the way for future investigations involving ultrafast dynamics of highly excited vibrational states or surface-sensitive coherent control experiments of ground-state reactions at solid-liquid interfaces.

  11. Unusual dimensionality effects and surface charge density in 2D Mg(OH)2.

    Science.gov (United States)

    Suslu, Aslihan; Wu, Kedi; Sahin, Hasan; Chen, Bin; Yang, Sijie; Cai, Hui; Aoki, Toshihiro; Horzum, Seyda; Kang, Jun; Peeters, Francois M; Tongay, Sefaattin

    2016-01-01

    We present two-dimensional Mg(OH)2 sheets and their vertical heterojunctions with CVD-MoS2 for the first time as flexible 2D insulators with anomalous lattice vibration and chemical and physical properties. New hydrothermal crystal growth technique enabled isolation of environmentally stable monolayer Mg(OH)2 sheets. Raman spectroscopy and vibrational calculations reveal that the lattice vibrations of Mg(OH)2 have fundamentally different signature peaks and dimensionality effects compared to other 2D material systems known to date. Sub-wavelength electron energy-loss spectroscopy measurements and theoretical calculations show that Mg(OH)2 is a 6 eV direct-gap insulator in 2D, and its optical band gap displays strong band renormalization effects from monolayer to bulk, marking the first experimental confirmation of confinement effects in 2D insulators. Interestingly, 2D-Mg(OH)2 sheets possess rather strong surface polarization (charge) effects which is in contrast to electrically neutral h-BN materials. Using 2D-Mg(OH)2 sheets together with CVD-MoS2 in the vertical stacking shows that a strong change transfer occurs from n-doped CVD-MoS2 sheets to Mg(OH)2, naturally depleting the semiconductor, pushing towards intrinsic doping limit and enhancing overall optical performance of 2D semiconductors. Results not only establish unusual confinement effects in 2D-Mg(OH)2, but also offer novel 2D-insulating material with unique physical, vibrational, and chemical properties for potential applications in flexible optoelectronics. PMID:26846617

  12. 2-D geometrical analysis of deformation

    International Nuclear Information System (INIS)

    Engineering structures such as dams, bridges, high rise buildings, etc. are subject to deformation. Deformation survey is therefore necessary to determine the magnitude and direction of such movements for the purpose of safety assessment. In this study, a strategy for two-step analyses for deformation survey rising the two dimensional (2-D) geodetic method has been developed, consisting of independent least squares estimation (LSE) of each epoch followed by deformation detection. Important aspects on LSE include global and local testing. In deformation detection, the following aspects were implemented; datum definition by the user. determination of stable datum points, geometrical analysis of deformation and graphic presentation. The developed strategy has been implemented in three computer programs, COMPUT, DEFORM and STRANS. Tests carried out with simulated and known data show that the developed strategy and programs are applicable for 2-D geometrical detection of deformation. (Author)

  13. 2D photonic-crystal optomechanical nanoresonator.

    Science.gov (United States)

    Makles, K; Antoni, T; Kuhn, A G; Deléglise, S; Briant, T; Cohadon, P-F; Braive, R; Beaudoin, G; Pinard, L; Michel, C; Dolique, V; Flaminio, R; Cagnoli, G; Robert-Philip, I; Heidmann, A

    2015-01-15

    We present the optical optimization of an optomechanical device based on a suspended InP membrane patterned with a 2D near-wavelength grating (NWG) based on a 2D photonic-crystal geometry. We first identify by numerical simulation a set of geometrical parameters providing a reflectivity higher than 99.8% over a 50-nm span. We then study the limitations induced by the finite value of the optical waist and lateral size of the NWG pattern using different numerical approaches. The NWG grating, pierced in a suspended InP 265-nm thick membrane, is used to form a compact microcavity involving the suspended nanomembrane as an end mirror. The resulting cavity has a waist size smaller than 10 μm and a finesse in the 200 range. It is used to probe the Brownian motion of the mechanical modes of the nanomembrane. PMID:25679837

  14. Robust and resistant 2D shape alignment

    DEFF Research Database (Denmark)

    Larsen, Rasmus; Eiriksson, Hrafnkell

    2001-01-01

    We express the alignment of 2D shapes as the minimization of the norm of a linear vector function. The minimization is done in the \\$l\\_1\\$, \\$l\\_2\\$ and the \\$l\\_\\$\\backslash\\$infty\\$ norms using well known standard numerical methods. In particular, the \\$l\\_1\\$ and the \\$l\\_\\$\\backslash\\$infty\\......We express the alignment of 2D shapes as the minimization of the norm of a linear vector function. The minimization is done in the \\$l\\_1\\$, \\$l\\_2\\$ and the \\$l\\_\\$\\backslash\\$infty\\$ norms using well known standard numerical methods. In particular, the \\$l\\_1\\$ and the \\$l......\\_\\$\\backslash\\$infty\\$ norm alignments are formulated as linear programming problems. The linear vector function formulation along with the different norms results in alignment methods that are both resistant from influence from outliers, robust wrt. errors in the annotation and capable of handling missing datapoints...

  15. 2D-Tasks for Cognitive Rehabilitation

    OpenAIRE

    Caballero Hernandez, Ruth; Martinez Moreno, Jose Maria; García Molina, A.; Ferrer Celma, S.; Solana Sánchez, Javier; Sanchez Carrion, R.; Fernandez Casado, E.; Pérez Rodríguez, Rodrigo; Gomez Pulido, A.; Anglès Tafalla, C.; Cáceres Taladriz, César; Ferre Vergada, M.; Roig Rovira, Teresa; Garcia Lopez, P.; Tormos Muñoz, Josep M.

    2011-01-01

    Neuropsychological Rehabilitation is a complex clinic process which tries to restore or compensate cognitive and behavioral disorders in people suffering from a central nervous system injury. Information and Communication Technologies (ICTs) in Biomedical Engineering play an essential role in this field, allowing improvement and expansion of present rehabilitation programs. This paper presents a set of cognitive rehabilitation 2D-Tasks for patients with Acquired Brain Injury (ABI). These t...

  16. Realistic and efficient 2D crack simulation

    Science.gov (United States)

    Yadegar, Jacob; Liu, Xiaoqing; Singh, Abhishek

    2010-04-01

    Although numerical algorithms for 2D crack simulation have been studied in Modeling and Simulation (M&S) and computer graphics for decades, realism and computational efficiency are still major challenges. In this paper, we introduce a high-fidelity, scalable, adaptive and efficient/runtime 2D crack/fracture simulation system by applying the mathematically elegant Peano-Cesaro triangular meshing/remeshing technique to model the generation of shards/fragments. The recursive fractal sweep associated with the Peano-Cesaro triangulation provides efficient local multi-resolution refinement to any level-of-detail. The generated binary decomposition tree also provides efficient neighbor retrieval mechanism used for mesh element splitting and merging with minimal memory requirements essential for realistic 2D fragment formation. Upon load impact/contact/penetration, a number of factors including impact angle, impact energy, and material properties are all taken into account to produce the criteria of crack initialization, propagation, and termination leading to realistic fractal-like rubble/fragments formation. The aforementioned parameters are used as variables of probabilistic models of cracks/shards formation, making the proposed solution highly adaptive by allowing machine learning mechanisms learn the optimal values for the variables/parameters based on prior benchmark data generated by off-line physics based simulation solutions that produce accurate fractures/shards though at highly non-real time paste. Crack/fracture simulation has been conducted on various load impacts with different initial locations at various impulse scales. The simulation results demonstrate that the proposed system has the capability to realistically and efficiently simulate 2D crack phenomena (such as window shattering and shards generation) with diverse potentials in military and civil M&S applications such as training and mission planning.

  17. 2D materials: Graphene and others

    Science.gov (United States)

    Bansal, Suneev Anil; Singh, Amrinder Pal; Kumar, Suresh

    2016-05-01

    Present report reviews the recent advancements in new atomically thick 2D materials. Materials covered in this review are Graphene, Silicene, Germanene, Boron Nitride (BN) and Transition metal chalcogenides (TMC). These materials show extraordinary mechanical, electronic and optical properties which make them suitable candidates for future applications. Apart from unique properties, tune-ability of highly desirable properties of these materials is also an important area to be emphasized on.

  18. Engineering light outcoupling in 2D materials

    KAUST Repository

    Lien, Derhsien

    2015-02-11

    When light is incident on 2D transition metal dichalcogenides (TMDCs), it engages in multiple reflections within underlying substrates, producing interferences that lead to enhancement or attenuation of the incoming and outgoing strength of light. Here, we report a simple method to engineer the light outcoupling in semiconducting TMDCs by modulating their dielectric surroundings. We show that by modulating the thicknesses of underlying substrates and capping layers, the interference caused by substrate can significantly enhance the light absorption and emission of WSe2, resulting in a ∼11 times increase in Raman signal and a ∼30 times increase in the photoluminescence (PL) intensity of WSe2. On the basis of the interference model, we also propose a strategy to control the photonic and optoelectronic properties of thin-layer WSe2. This work demonstrates the utilization of outcoupling engineering in 2D materials and offers a new route toward the realization of novel optoelectronic devices, such as 2D LEDs and solar cells.

  19. Reversible dimer formation and stability of the anti-tumour single-chain Fv antibody MFE-23 by neutron scattering, analytical ultracentrifugation, and NMR and FT-IR spectroscopy.

    Science.gov (United States)

    Lee, Yie Chia; Boehm, Mark K; Chester, Kerry A; Begent, Richard H J; Perkins, Stephen J

    2002-06-28

    MFE-23 is a single chain Fv (scFv) antibody molecule used to target colorectal cancer through its high affinity for the tumour marker carcinoembryonic antigen (CEA). ScFv molecules are formed from peptide-linked antibody V(H) and V(L) domains, and many of these form dimers. Our recent crystal structure for MFE-23 showed that this formed an unusual symmetric back-to-back association of two monomers that is consistent with a domain-swapped diabody structure. Neutron scattering and modelling fits showed that MFE-23 existed as compact V(H)-V(L)-linked monomers at therapeutically relevant concentrations below 1 mg/ml. Size-exclusion gel chromatography showed that the monomeric and dimeric forms of MFE-23 could be separated, and that the proportions of these two forms depended on the starting MFE-23 concentration. Sedimentation equilibrium experiments by analytical ultracentrifugation at nine concentrations of MFE-23 indicated a reversible monomer-dimer self-association equilibrium with an association constant of 1.9x10(3)-2.2x10(3) M(-1). Sedimentation velocity experiments using the time derivative g(s(*)) method showed that MFE-23-His has a concentration-dependent weight average sedimentation coefficient that increased from 1.8 S for the monomer to about 3-6 S for the dimer. Both values agreed with those calculated from the MFE-23 crystal structure. In relation to the thermal stability of MFE-23, denaturation experiments by (1)H NMR and FT-IR spectroscopy showed that the molecule is stable up to 47 degrees C, after which denaturation was irreversible. MFE-23 dimerisation is discussed in terms of a new model for diabody structures, in which the V(H) and V(L) domains in the monomer are able to dissociate and reassociate to form a dimer, or diabody, but in which symmetric back-to-back contacts between the two monomers are formed. This dimerisation in solution is attributed to the complementary nature of the C-terminal surface of the MFE-23 monomer. Crystal structures for

  20. Experimental, computational and chemometrics studies of BSA-vitamin B6 interaction by UV-Vis, FT-IR, fluorescence spectroscopy, molecular dynamics simulation and hard-soft modeling methods.

    Science.gov (United States)

    Manouchehri, Firouzeh; Izadmanesh, Yahya; Aghaee, Elham; Ghasemi, Jahan B

    2016-10-01

    The interaction of pyridoxine (Vitamin B6) with bovine serum albumin (BSA) is investigated under pseudo-physiological conditions by UV-Vis, fluorescence and FTIR spectroscopy. The intrinsic fluorescence of BSA was quenched by VB6, which was rationalized in terms of the static quenching mechanism. According to fluorescence quenching calculations, the bimolecular quenching constant (kq), dynamic quenching (KSV) and static quenching (KLB) at 310K were obtained. The efficiency of energy transfer and the distance between the donor (BSA) and the acceptor (VB6) were calculated by Foster's non-radiative energy transfer theory and were equal to 41.1% and 2.11nm. The collected UV-Vis and fluorescence spectra were combined into a row-and column-wise augmented matrix and resolved by multivariate curve resolution-alternating least squares (MCR-ALS). MCR-ALS helped to estimate the stoichiometry of interactions, concentration profiles and pure spectra for three species (BSA, VB6 and VB6-BSA complex) existed in the interaction procedure. Based on the MCR-ALS results, using mass balance equations, a model was developed and binding constant of complex was calculated using non-linear least squares curve fitting. FT-IR spectra showed that the conformation of proteins was altered in presence of VB6. Finally, the combined docking and molecular dynamics (MD) simulations were used to estimate the binding affinity of VB6 to BSA. Five-nanosecond MD simulations were performed on bovine serum albumin (BSA) to study the conformational features of its ligand binding site. From MD results, eleven BSA snapshots were extracted, at every 0.5ns, to explore the binding affinity (GOLD score) of VB6 using a docking procedure. MD simulations indicated that there is a considerable flexibility in the structure of protein that affected ligand recognition. Structural analyses and docking simulations indicated that VB6 binds to site I and GOLD score values depend on the conformations of both BSA and ligand

  1. Investigation of organometallic reaction mechanisms with one and two dimensional vibrational spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Cahoon, James Francis [Univ. of California, Berkeley, CA (United States)

    2008-12-01

    One and two dimensional time-resolved vibrational spectroscopy has been used to investigate the elementary reactions of several prototypical organometallic complexes in room temperature solution. The electron transfer and ligand substitution reactions of photogenerated 17-electron organometallic radicals CpW(CO)3 and CpFe(CO)2 have been examined with one dimensional spectroscopy on the picosecond through microsecond time-scales, revealing the importance of caging effects and odd-electron intermediates in these reactions. Similarly, an investigation of the photophysics of the simple Fischer carbene complex Cr(CO)5[CMe(OMe)] showed that this class of molecule undergoes an unusual molecular rearrangement on the picosecond time-scale, briefly forming a metal-ketene complex. Although time-resolved spectroscopy has long been used for these types of photoinitiated reactions, the advent of two dimensional vibrational spectroscopy (2D-IR) opens the possibility to examine the ultrafast dynamics of molecules under thermal equilibrium conditions. Using this method, the picosecond fluxional rearrangements of the model metal carbonyl Fe(CO)5 have been examined, revealing the mechanism, time-scale, and transition state of the fluxional reaction. The success of this experiment demonstrates that 2D-IR is a powerful technique to examine the thermally-driven, ultrafast rearrangements of organometallic molecules in solution.

  2. Investigation of organometallic reaction mechanisms with one and two dimensional vibrational spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Cahoon, James Francis

    2008-12-16

    One and two dimensional time-resolved vibrational spectroscopy has been used to investigate the elementary reactions of several prototypical organometallic complexes in room temperature solution. The electron transfer and ligand substitution reactions of photogenerated 17-electron organometallic radicals CpW(CO){sub 3} and CpFe(CO){sub 2} have been examined with one dimensional spectroscopy on the picosecond through microsecond time-scales, revealing the importance of caging effects and odd-electron intermediates in these reactions. Similarly, an investigation of the photophysics of the simple Fischer carbene complex Cr(CO){sub 5}[CMe(OMe)] showed that this class of molecule undergoes an unusual molecular rearrangement on the picosecond time-scale, briefly forming a metal-ketene complex. Although time-resolved spectroscopy has long been used for these types of photoinitiated reactions, the advent of two dimensional vibrational spectroscopy (2D-IR) opens the possibility to examine the ultrafast dynamics of molecules under thermal equilibrium conditions. Using this method, the picosecond fluxional rearrangements of the model metal carbonyl Fe(CO){sub 5} have been examined, revealing the mechanism, time-scale, and transition state of the fluxional reaction. The success of this experiment demonstrates that 2D-IR is a powerful technique to examine the thermally-driven, ultrafast rearrangements of organometallic molecules in solution.

  3. In-Cell Protein Structures from 2D NMR Experiments.

    Science.gov (United States)

    Müntener, Thomas; Häussinger, Daniel; Selenko, Philipp; Theillet, Francois-Xavier

    2016-07-21

    In-cell NMR spectroscopy provides atomic resolution insights into the structural properties of proteins in cells, but it is rarely used to solve entire protein structures de novo. Here, we introduce a paramagnetic lanthanide-tag to simultaneously measure protein pseudocontact shifts (PCSs) and residual dipolar couplings (RDCs) to be used as input for structure calculation routines within the Rosetta program. We employ this approach to determine the structure of the protein G B1 domain (GB1) in intact Xenopus laevis oocytes from a single set of 2D in-cell NMR experiments. Specifically, we derive well-defined GB1 ensembles from low concentration in-cell NMR samples (∼50 μM) measured at moderate magnetic field strengths (600 MHz), thus offering an easily accessible alternative for determining intracellular protein structures. PMID:27379949

  4. Solution structure of d-GAATTCGAATTC by 2D NMR

    International Nuclear Information System (INIS)

    A new approach based on the correlated spectroscopy (COSY) in 2D NMR has been described for determination of sugar geometries in oligonucleotides. Under the usual low resolution conditions employed in COSY, the intensities of cross peaks depend on the magnitudes of coupling constants. There are five vicinal coupling constants in a deoxyribose ring which are sensitive to the sugar geometry. The presence, absence and rough comparison of relative intensities of COSY cross peaks arising from such coupling constants enable one to fix the sugar conformation to a fair degree of precision. The methodology has been applied to d-GAATTCGAATTC. It is observed that ten out of the twelve nucleotide units in this sequence exhibit a rare O1'-endo geometry. The EcoRI cleavage sites in the dodecanucleotide show an interesting variation in the conformation with the two sugars attached to the Gs acquiring a geometry between C2'-endo and C4'-endo. (Auth.)

  5. Growth of CaIrO3 and Gd2Ir2O7 by MBE

    Science.gov (United States)

    Nie, Yuefeng; Held, Rainer; Chatterjee, Shouvik; Monkman, Eric; Shai, Daniel; Harter, John; Burganov, Bulat; Adamo, Carolina; Schlom, Darrell; Shen, Kyle

    2012-02-01

    Recently, it was pointed out that the 5d transition metal iridium oxides (iridates) are promising candidates to realize topological insulators, which provide a unique platform in studying the interplay of Coulomb interactions, spin-orbit coupling, and the band topology of solids. We successfully grew epitaxial perovskite CaIrO3 and pyrochlore Gd2Ir2O7 films by reactive molecular-beam epitaxy (MBE). A range of biaxial strains for epitaxial CaIrO3 films was achieved by growing on different substrates. Angle-resolved photoemission spectroscopy (ARPES) will be used to investigate the electronic structure of the epitaxial CaIrO3 and Gd2Ir2O7 films.

  6. 2D Plasmonics for Enabling Novel Light-Matter Interactions

    CERN Document Server

    Kaminer, Ido; Zhen, Bo; Joannopoulos, John D; Soljacic, Marin

    2015-01-01

    The physics of light-matter interactions is strongly constrained by both the small value of the fine-structure constant and the small size of the atom. Overcoming these limitations is a long-standing challenge. Recent theoretical and experimental breakthroughs have shown that two dimensional systems, such as graphene, can support strongly confined light in the form of plasmons. These 2D systems have a unique ability to squeeze the wavelength of light by over two orders of magnitude. Such high confinement requires a revisitation of the main assumptions of light-matter interactions. In this letter, we provide a general theory of light-matter interactions in 2D systems which support plasmons. This theory reveals that conventionally forbidden light-matter interactions, such as: high-order multipolar transitions, two-plasmon spontaneous emission, and spin-flip transitions can occur on very short time-scales - comparable to those of conventionally fast transitions. Our findings enable new platforms for spectroscopy...

  7. Propagator-resolved 2D exchange in porous media in the inhomogeneous magnetic field.

    Science.gov (United States)

    Burcaw, Lauren M; Hunter, Mark W; Callaghan, Paul T

    2010-08-01

    We present a propagator-resolved 2D exchange spectroscopy technique for observing fluid motion in a porous medium. The susceptibility difference between the matrix and the fluid is exploited to produce an inhomogeneous internal magnetic field, causing the Larmor frequency to change as molecules migrate. We test our method using a randomly packed monodisperse 100 microm diameter glass bead matrix saturated with distilled water. Building upon previous 2D exchange spectroscopy work we add a displacement dimension which allows us to obtain 2D exchange spectra that are defined by both mixing time and spatial displacement rather than by mixing time alone. We also simulate our system using a Monte Carlo process in a random nonpenetrating monodisperse bead pack, finding good agreement with experiment. A simple analytic model is used to interpret the NMR data in terms of a characteristic length scale over which molecules must diffuse to sample the inhomogeneous field distribution. PMID:20554230

  8. Panchromatic Light Capture and Efficient Excitation Transfer Leading to Near-IR Emission of BODIPY Oligomers.

    Science.gov (United States)

    Sharma, Ritambhara; Gobeze, Habtom B; D'Souza, Francis; Ravikanth, Mangalampalli

    2016-08-18

    All-BODIPY-based (BODIPY=boron-dipyrromethene) donor-acceptor systems capable of wide-band absorbance leading to efficient energy transfer in the near-IR region are reported. A covalently linked 3-pyrrolyl BODIPY-BODIPY dimer building block bearing an ethynyl group at the meso-aryl position is synthesized and coupled with three different monomeric BODIPY/pyrrolyl BODIPY building blocks with a bromo/iodo group under Pd(0) coupling conditions to obtain three covalently linked 3-pyrrolyl-BODIPY-based donor-acceptor oligomers in 19-29 % yield. The oligomers are characterized in detail by 1D and 2D NMR spectroscopy, high-resolution mass spectrometry, and optical spectroscopy. Due to the presence of different functionalized BODIPY derivatives in the oligomers, panchromatic light capture (300-725 nm) is witnessed. Fluorescence studies reveal singlet-singlet energy transfer from BODIPY monomer to BODIPY dimer leading to emission in the 700-800 nm range. Theoretical modeling according to the Förster mechanism predicts ultrafast energy transfer due to good spectral overlap of the donor and acceptor entities. Femtosecond transient absorption studies confirm this to be the case and thus show the relevance of the currently developed all-BODIPY-based energy-funneling supramolecular sytems with near-IR emission to solar-energy harvesting applications. PMID:27168532

  9. Fabrication method and microstructural characteristics of coal-tar-pitch-based 2D carbon/carbon composites

    Science.gov (United States)

    Esmaeeli, Mohammad; Khosravi, Hamed; Mirhabibi, Alireza

    2015-02-01

    The lignin-cellulosic texture of wood was used to produce two-dimensional (2D) carbon/carbon (C/C) composites using coal tar pitch. Ash content tests were conducted to select two samples among the different kinds of woods present in Iran, including walnut, white poplar, cherry, willow, buttonwood, apricots, berry, and blue wood. Walnut and white poplar with ash contents of 1.994wt% and 0.351wt%, respectively, were selected. The behavior of these woods during pyrolysis was investigated by differential thermal analysis (DTA) and thermo gravimetric (TG) analysis. The bulk density and open porosity were measured after carbonization and densification. The microstructural characteristics of samples were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared (FT-IR) spectroscopy. The results indicate that the density of both the walnut and white poplar is increased, and the open porosity is decreased with the increasing number of carbonization cycles. The XRD patterns of the wood charcoal change gradually with increasing pyrolysis temperature, possibly as a result of the ultra-structural changes in the charcoal or the presence of carbonized coal tar pitch in the composite's body.

  10. Synthesis and Crystal Structure of a Novel 2D Coordination Polymer [Cu3(mal)2(di-2-pyridlyktone)2

    Institute of Scientific and Technical Information of China (English)

    ZHANG Mei-Li; WU Ya-Pan; WANG Ji-Jiang; REN Yi-Xia; CHEN Xiao-Li

    2011-01-01

    A novel coordination polymer of CuⅡ with flexible ligands, namely, [Cu3(mal)2(di2-pyridlyktone)2] (1, H2mal = maleie acid), was synthesized and characterized by single-crystal X-ray diffraction, thermogravimetric analyses, elemental analysis and IR spectroscopy. The structure indicates that the complex crystallizes in monoclinic, space group P21/c with a = 10.268(2), b =17.737(3), c = 8.038(1) (A), β = 98.275(2)°, V = 1448.6(4) (A)3, Z = 2, Dc = 1.883 Mg·m-3, μ = 2.260 mm-1, F(000) = 826, and the final R = 0.0321 and wR = 0.0820. In 1, three CuⅡ centers (Cu(1),Cu(2), Cu(1A)) are bridged by two uncommonμ3-bridging H2mal ligands, furnishing a centrosymmetric trimetallic unit. Via further Cu-Ocoo coordination interactions, extention of these trimetallic units in two directions gives rise to an infinite corrugated 2D layer. In addition, thermal stability and electrochemistry of 1 were studied.

  11. Limit theorems for 2D invasion percolation

    CERN Document Server

    Damron, Michael

    2010-01-01

    We prove limit theorems and variance estimates for quantities related to ponds and outlets for 2D invasion percolation. We first exhibit several properties of a sequence (O(n)) of outlet variables, the n-th of which gives the number of outlets in the box centered at the origin of side length 2^n. The most important of these properties describe the sequence's renewal structure and exponentially fast mixing behavior. We use these to prove a central limit theorem and strong law of large numbers for (O(n)). We then show consequences of these limit theorems for the pond radii and outlet weights.

  12. Interparticle attraction in 2D complex plasmas

    CERN Document Server

    Kompaneets, Roman; Ivlev, Alexei V

    2015-01-01

    Complex (dusty) plasmas allow experimental studies of various physical processes occurring in classical liquids and solids by directly observing individual microparticles. A major problem is that the interaction between microparticles is generally not molecular-like. In this Letter, we propose how to achieve a molecular-like interaction potential in laboratory 2D complex plasmas. We argue that this principal aim can be achieved by using relatively small microparticles and properly adjusting discharge parameters. If experimentally confirmed, this will make it possible to employ complex plasmas as a model system with an interaction potential resembling that of conventional liquids.

  13. Periodically sheared 2D Yukawa systems

    Energy Technology Data Exchange (ETDEWEB)

    Kovács, Anikó Zsuzsa [Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, Konkoly-Thege Miklós str. 29-33, H-1121 Budapest (Hungary); Hartmann, Peter [Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, Konkoly-Thege Miklós str. 29-33, H-1121 Budapest (Hungary); Center for Astrophysics, Space Physics and Engineering Research (CASPER), One Bear Place 97310, Baylor University, Waco, Texas 76798 (United States); Donkó, Zoltán [Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, Konkoly-Thege Miklós str. 29-33, H-1121 Budapest (Hungary); Physics Department, Boston College, Chestnut Hill, Massachusetts 20467 (United States)

    2015-10-15

    We present non-equilibrium molecular dynamics simulation studies on the dynamic (complex) shear viscosity of a 2D Yukawa system. We have identified a non-monotonic frequency dependence of the viscosity at high frequencies and shear rates, an energy absorption maximum (local resonance) at the Einstein frequency of the system at medium shear rates, an enhanced collective wave activity, when the excitation is near the plateau frequency of the longitudinal wave dispersion, and the emergence of significant configurational anisotropy at small frequencies and high shear rates.

  14. Extrinsic curvature induced 2-d gravity

    CERN Document Server

    Viswanathan, K S

    1993-01-01

    Abtract: 2-dimensional fermions are coupled to extrinsic geometry of a conformally immersed surface in ${\\bf R}^3$ through gauge coupling. By integrating out the fermions, we obtain a WZNW action involving extrinsic curvature of the surface. Restricting the resulting effective action to surfaces of $h\\sqrt g=1$, an explicit form of the action invariant under Virasaro symmetry is obtained. This action is a sum of the geometric action for the Virasaro group and the light-cone action of 2-d gravity plus an interaction term. The central charges of the theory in both the left and right sectors are calculated.

  15. 2-d Simulations of Test Methods

    DEFF Research Database (Denmark)

    Thrane, Lars Nyholm

    2004-01-01

    using both a Newton and Bingham model for characterisation of the rheological properties of the concrete. From the results, it is expected that both the slump flow and L-box can be simulated quite accurately when the model is extended to 3-d and the concrete is characterised according to the Bingham...... approach is presented by showing initial results from 2-d simulations of the empirical test methods slump flow and L-box. This method assumes a homogeneous material, which is expected to correspond to particle suspensions e.g. concrete, when it remains stable. The simulations have been carried out when...... model....

  16. Instant HTMl5 2D platformer

    CERN Document Server

    Temple, Aidan

    2013-01-01

    Filled with practical, step-by-step instructions and clear explanations for the most important and useful tasks. The step-by-step approach taken by this book will show you how to develop a 2D HTML5 platformer-based game that you will be able to publish to multiple devices.This book is great for anyone who has an interest in HTML5 games development, and who already has a basic to intermediate grasp on both the HTML markup and JavaScript programming languages. Therefore, due to this requirement, the book will not discuss the inner workings of either of these languages but will instead attempt to

  17. Phase Engineering of 2D Tin Sulfides.

    OpenAIRE

    Mutlu, Z; Wu, RJ; Wickramaratne, D.; Shahrezaei, S; Liu, C; Temiz, S; Patalano, A; M Ozkan; Lake, RK; Mkhoyan, KA; Ozkan, CS

    2016-01-01

    Tin sulfides can exist in a variety of phases and polytypes due to the different oxidation states of Sn. A subset of these phases and polytypes take the form of layered 2D structures that give rise to a wide host of electronic and optical properties. Hence, achieving control over the phase, polytype, and thickness of tin sulfides is necessary to utilize this wide range of properties exhibited by the compound. This study reports on phase-selective growth of both hexagonal tin (IV) sulfide SnS2...

  18. Interparticle Attraction in 2D Complex Plasmas

    Science.gov (United States)

    Kompaneets, Roman; Morfill, Gregor E.; Ivlev, Alexei V.

    2016-03-01

    Complex (dusty) plasmas allow experimental studies of various physical processes occurring in classical liquids and solids by directly observing individual microparticles. A major problem is that the interaction between microparticles is generally not molecularlike. In this Letter, we propose how to achieve a molecularlike interaction potential in laboratory 2D complex plasmas. We argue that this principal aim can be achieved by using relatively small microparticles and properly adjusting discharge parameters. If experimentally confirmed, this will make it possible to employ complex plasmas as a model system with an interaction potential resembling that of conventional liquids.

  19. WFR-2D: an analytical model for PWAS-generated 2D ultrasonic guided wave propagation

    Science.gov (United States)

    Shen, Yanfeng; Giurgiutiu, Victor

    2014-03-01

    This paper presents WaveFormRevealer 2-D (WFR-2D), an analytical predictive tool for the simulation of 2-D ultrasonic guided wave propagation and interaction with damage. The design of structural health monitoring (SHM) systems and self-aware smart structures requires the exploration of a wide range of parameters to achieve best detection and quantification of certain types of damage. Such need for parameter exploration on sensor dimension, location, guided wave characteristics (mode type, frequency, wavelength, etc.) can be best satisfied with analytical models which are fast and efficient. The analytical model was constructed based on the exact 2-D Lamb wave solution using Bessel and Hankel functions. Damage effects were inserted in the model by considering the damage as a secondary wave source with complex-valued directivity scattering coefficients containing both amplitude and phase information from wave-damage interaction. The analytical procedure was coded with MATLAB, and a predictive simulation tool called WaveFormRevealer 2-D was developed. The wave-damage interaction coefficients (WDICs) were extracted from harmonic analysis of local finite element model (FEM) with artificial non-reflective boundaries (NRB). The WFR-2D analytical simulation results were compared and verified with full scale multiphysics finite element models and experiments with scanning laser vibrometer. First, Lamb wave propagation in a pristine aluminum plate was simulated with WFR-2D, compared with finite element results, and verified by experiments. Then, an inhomogeneity was machined into the plate to represent damage. Analytical modeling was carried out, and verified by finite element simulation and experiments. This paper finishes with conclusions and suggestions for future work.

  20. Comments on Thermalization in 2D CFT

    CERN Document Server

    de Boer, Jan

    2016-01-01

    We revisit certain aspects of thermalization in 2D CFT. In particular, we consider similarities and differences between the time dependence of correlation functions in various states in rational and non-rational CFTs. We also consider the distinction between global and local thermalization and explain how states obtained by acting with a diffeomorphism on the ground state can appear locally thermal, and we review why the time-dependent expectation value of the energy-momentum tensor is generally a poor diagnostic of global thermalization. Since all 2D CFTs have an infinite set of commuting conserved charges, generic initial states might be expected to give rise to a generalized Gibbs ensemble rather than a pure thermal ensemble at late times. We construct the holographic dual of the generalized Gibbs ensemble and show that, to leading order, it is still described by a BTZ black hole. The extra conserved charges, while rendering $c < 1$ theories essentially integrable, therefore seem to have little effect o...

  1. Multienzyme Inkjet Printed 2D Arrays.

    Science.gov (United States)

    Gdor, Efrat; Shemesh, Shay; Magdassi, Shlomo; Mandler, Daniel

    2015-08-19

    The use of printing to produce 2D arrays is well established, and should be relatively facile to adapt for the purpose of printing biomaterials; however, very few studies have been published using enzyme solutions as inks. Among the printing technologies, inkjet printing is highly suitable for printing biomaterials and specifically enzymes, as it offers many advantages. Formulation of the inkjet inks is relatively simple and can be adjusted to a variety of biomaterials, while providing nonharmful environment to the enzymes. Here we demonstrate the applicability of inkjet printing for patterning multiple enzymes in a predefined array in a very straightforward, noncontact method. Specifically, various arrays of the enzymes glucose oxidase (GOx), invertase (INV) and horseradish peroxidase (HP) were printed on aminated glass surfaces, followed by immobilization using glutardialdehyde after printing. Scanning electrochemical microscopy (SECM) was used for imaging the printed patterns and to ascertain the enzyme activity. The successful formation of 2D arrays consisting of enzymes was explored as a means of developing the first surface confined enzyme based logic gates. Principally, XOR and AND gates, each consisting of two enzymes as the Boolean operators, were assembled, and their operation was studied by SECM. PMID:26214072

  2. IOT Overview: IR Instruments

    Science.gov (United States)

    Mason, E.

    In this instrument review chapter the calibration plans of ESO IR instruments are presented and briefly reviewed focusing, in particular, on the case of ISAAC, which has been the first IR instrument at VLT and whose calibration plan served as prototype for the coming instruments.

  3. IR Hot Wave

    Energy Technology Data Exchange (ETDEWEB)

    Graham, T. B.

    2010-04-01

    The IR Hot Wave{trademark} furnace is a breakthrough heat treatment system for manufacturing metal components. Near-infrared (IR) radiant energy combines with IR convective heating for heat treating. Heat treatment is an essential process in the manufacture of most components. The controlled heating and cooling of a metal or metal alloy alters its physical, mechanical, and sometimes chemical properties without changing the object's shape. The IR Hot Wave{trademark} furnace offers the simplest, quickest, most efficient, and cost-effective heat treatment option for metals and metal alloys. Compared with other heat treatment alternatives, the IR Hot Wave{trademark} system: (1) is 3 to 15 times faster; (2) is 2 to 3 times more energy efficient; (3) is 20% to 50% more cost-effective; (4) has a {+-}1 C thermal profile compared to a {+-}10 C thermal profile for conventional gas furnaces; and (5) has a 25% to 50% smaller footprint.

  4. 2D to 3D transition of polymeric carbon nitride nanosheets

    Energy Technology Data Exchange (ETDEWEB)

    Chamorro-Posada, Pedro [Dpto. de Teoría de la Señal y Comunicaciones e IT, Universidad de Valladolid, ETSI Telecomunicación, Paseo Belén 15, 47011 Valladolid (Spain); Vázquez-Cabo, José [Dpto. de Teoría de la Señal y Comunicaciones, Universidad de Vigo, ETSI Telecomunicación, Lagoas Marcosende s/n, Vigo (Spain); Sánchez-Arévalo, Francisco M. [Instituto de Investigaciones en Materiales (IIM), Universidad Nacional Autónoma de México, Apdo. Postal 70–360, Cd. Universitaria, México D.F. 04510 (Mexico); Martín-Ramos, Pablo [Dpto. de Teoría de la Señal y Comunicaciones e IT, Universidad de Valladolid, ETSI Telecomunicación, Paseo Belén 15, 47011 Valladolid (Spain); Laboratorio de Materiales Avanzados (Advanced Materials Laboratory) ETSIIAA, Universidad de Valladolid, Avenida de Madrid 44, 34004 Palencia (Spain); Martín-Gil, Jesús; Navas-Gracia, Luis M. [Laboratorio de Materiales Avanzados (Advanced Materials Laboratory) ETSIIAA, Universidad de Valladolid, Avenida de Madrid 44, 34004 Palencia (Spain); Dante, Roberto C., E-mail: rcdante@yahoo.com [Laboratorio de Materiales Avanzados (Advanced Materials Laboratory) ETSIIAA, Universidad de Valladolid, Avenida de Madrid 44, 34004 Palencia (Spain)

    2014-11-15

    The transition from a prevalent turbostratic arrangement with low planar interactions (2D) to an array of polymeric carbon nitride nanosheets with stronger interplanar interactions (3D), occurring for samples treated above 650 °C, was detected by terahertz-time domain spectroscopy (THz-TDS). The simulated 3D material made of stacks of shifted quasi planar sheets composed of zigzagged polymer ribbons, delivered a XRD simulated pattern in relatively good agreement with the experimental one. The 2D to 3D transition was also supported by the simulation of THz-TDS spectra obtained from quantum chemistry calculations, in which the same broad bands around 2 THz and 1.5 THz were found for 2D and 3D arrays, respectively. This transition was also in accordance with the tightening of the interplanar distance probably due to an interplanar π bond contribution, as evidenced also by a broad absorption around 2.6 eV in the UV–vis spectrum, which appeared in the sample treated at 650 °C, and increased in the sample treated at 700 °C. The band gap was calculated for 1D and 2D cases. The value of 3.374 eV for the 2D case is, within the model accuracy and precision, in a relative good agreement with the value of 3.055 eV obtained from the experimental results. - Graphical abstract: 2D lattice mode vibrations and structural changes correlated with the so called “2D to 3D transition”. - Highlights: • A 2D to 3D transition has been detected for polymeric carbon nitride. • THz-TDS allowed us to discover and detect the 2D to 3D transition of polymeric carbon nitride. • We propose a structure for polymeric carbon nitride confirming it with THz-TDS.

  5. Use of X-ray diffraction, molecular simulations, and spectroscopy to determine the molecular packing in a polymer-fullerene bimolecular crystal

    KAUST Repository

    Miller, Nichole Cates

    2012-09-05

    The molecular packing in a polymer: fullerene bimolecular crystal is determined using X-ray diffraction (XRD), molecular mechanics (MM) and molecular dynamics (MD) simulations, 2D solid-state NMR spectroscopy, and IR absorption spectroscopy. The conformation of the electron-donating polymer is significantly disrupted by the incorporation of the electron-accepting fullerene molecules, which introduce twists and bends along the polymer backbone and 1D electron-conducting fullerene channels. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Use of X-ray diffraction, molecular simulations, and spectroscopy to determine the molecular packing in a polymer-fullerene bimolecular crystal

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Nichole Cates; Gysel, Roman; Sweetnam, Sean; McGehee, Michael D. [Department of Materials Science and Engineering, Stanford University, Stanford, CA (United States); Cho, Eunkyung [School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA (United States); School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA (United States); Junk, Matthias J.N.; Chmelka, Bradley F. [Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, CA (United States); Risko, Chad; Kim, Dongwook; Bredas, Jean-Luc [School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA (United States); Miller, Chad E. [Department of Materials Science and Engineering, Stanford University, Stanford, CA (United States); Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA (United States); Richter, Lee J.; Kline, R. Joseph [National Institute of Standards and Technology, Gaithersburg, MD (United States); Heeney, Martin; McCulloch, Iain [Department of Chemistry, Imperial College London (United Kingdom); Amassian, Aram [King Abdullah University of Science and Technology (KAUST), Physical Sciences and Engineering Division, Thuwal (Saudi Arabia); Acevedo-Feliz, Daniel; Knox, Christopher [King Abdullah University of Science and Technology (KAUST), Visualization Core Laboratory, Thuwal (Saudi Arabia); Hansen, Michael Ryan; Dudenko, Dmytro [Max Planck Institute for Polymer Research, Mainz (Germany); Toney, Michael F. [Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA (United States)

    2012-11-27

    The molecular packing in a polymer: fullerene bimolecular crystal is determined using X-ray diffraction (XRD), molecular mechanics (MM) and molecular dynamics (MD) simulations, 2D solid-state NMR spectroscopy, and IR absorption spectroscopy. The conformation of the electron-donating polymer is significantly disrupted by the incorporation of the electron-accepting fullerene molecules, which introduce twists and bends along the polymer backbone and 1D electron-conducting fullerene channels. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Locality constraints and 2D quasicrystals

    International Nuclear Information System (INIS)

    The plausible assumption that long-range interactions between atoms are negligible in a quasicrystal leaks to the study of tilings that obey constraints on the local configurations of tiles. The theory of such constraints (called matching rules) for 2D quasicrystal tilings is reviewed here. Different types of matching rules are defined and examples of tilings obeying them are given where known. The role of tile decoration is discussed and is shown to be significant in at least two cases (octagonal and dodecagonal duals of periodic 4-grids and 6-grids). A new result is introduced: a constructive procedure is described for generating weak matching rules for tilings with N-fold symmetry, for any N that is either a prime number or twice a prime number. The physics associated with weak matching rules, results on local growth rules, and the case of icosahedral symmetry are all briefly discussed. (author). 29 refs, 4 figs

  8. 2D Cooling of Magnetized Neutron Stars

    CERN Document Server

    Aguilera, Deborah N; Miralles, Juan A

    2007-01-01

    Context: Many thermally emitting isolated neutron stars have magnetic fields larger than 10^{13}G. A realistic cooling model should be reconsidered including the presence of high magnetic fields. Aims: We investigate the effects of anisotropic temperature distribution and Joule heating on the cooling of magnetized neutron stars. Methods: The 2D heat transfer equation with anisotropic thermal conductivity tensor and including all relevant neutrino emission processes is solved for realistic models of the neutron star interior and crust. Results: The presence of the magnetic field affects significantly the thermal surface distribution and the cooling history during both, the early neutrino cooling era and the late photon cooling era. Conclusions: There is a huge effect of the Joule heating on the thermal evolution of strongly magnetized neutron stars. Magnetic fields and Joule heating play a key role in maintaining magnetars warm for a long time. Moreover, this effect is also important for intermediate field neu...

  9. Alignment free characterization of 2D gratings

    CERN Document Server

    Madsen, Morten Hannibal; Hansen, Poul-Erik; Jørgensen, Jan Friis

    2015-01-01

    Fast characterization of 2-dimensional gratings is demonstrated using a Fourier lens optical system and a differential optimization algorithm. It is shown that both the grating specific parameters such as the basis vectors and the angle between them and the alignment of the sample, such as the rotation of the sample around the x-, y-, and z-axis, can be deduced from a single measurement. More specifically, the lattice vectors and the angle between them have been measured, while the corrections of the alignment parameters are used to improve the quality of the measurement, and hence reduce the measurement uncertainty. Alignment free characterization is demonstrated on both a 2D hexagonal grating with a period of 700 nm and a checkerboard grating with a pitch of 3000 nm. The method can also be used for both automatic alignment and in-line characterization of gratings.

  10. Area preserving diffeomorphisms and 2-d gravity

    CERN Document Server

    La, H S

    1995-01-01

    Area preserving diffeomorphisms of a 2-d compact Riemannian manifold with or without boundary are studied. We find two classes of decompositions of a Riemannian metric, namely, h- and g-decomposition, that help to formulate a gravitational theory which is area preserving diffeomorphism (SDiffM-) invariant but not necessarily diffeomorphism invariant. The general covariance of equations of motion of such a theory can be achieved by incorporating proper Weyl rescaling. The h-decomposition makes the conformal factor of a metric SDiffM-invariant and the rest of the metric invariant under conformal diffeomorphisms, whilst the g-decomposition makes the conformal factor a SDiffM scalar and the rest a SDiffM tensor. Using these, we reformulate Liouville gravity in SDiffM invariant way. In this context we also further clarify the dual formulation of Liouville gravity introduced by the author before, in which the affine spin connection is dual to the Liouville field.

  11. Graphene suspensions for 2D printing

    Science.gov (United States)

    Soots, R. A.; Yakimchuk, E. A.; Nebogatikova, N. A.; Kotin, I. A.; Antonova, I. V.

    2016-04-01

    It is shown that, by processing a graphite suspension in ethanol or water by ultrasound and centrifuging, it is possible to obtain particles with thicknesses within 1-6 nm and, in the most interesting cases, 1-1.5 nm. Analogous treatment of a graphite suspension in organic solvent yields eventually thicker particles (up to 6-10 nm thick) even upon long-term treatment. Using the proposed ink based on graphene and aqueous ethanol with ethylcellulose and terpineol additives for 2D printing, thin (~5 nm thick) films with sheet resistance upon annealing ~30 MΩ/□ were obtained. With the ink based on aqueous graphene suspension, the sheet resistance was ~5-12 kΩ/□ for 6- to 15-nm-thick layers with a carrier mobility of ~30-50 cm2/(V s).

  12. Numerical Evaluation of 2D Ground States

    Science.gov (United States)

    Kolkovska, Natalia

    2016-02-01

    A ground state is defined as the positive radial solution of the multidimensional nonlinear problem \\varepsilon propto k_ bot 1 - ξ with the function f being either f(u) =a|u|p-1u or f(u) =a|u|pu+b|u|2pu. The numerical evaluation of ground states is based on the shooting method applied to an equivalent dynamical system. A combination of fourth order Runge-Kutta method and Hermite extrapolation formula is applied to solving the resulting initial value problem. The efficiency of this procedure is demonstrated in the 1D case, where the maximal difference between the exact and numerical solution is ≈ 10-11 for a discretization step 0:00025. As a major application, we evaluate numerically the critical energy constant. This constant is defined as a functional of the ground state and is used in the study of the 2D Boussinesq equations.

  13. VizieR Online Data Catalog: c2d Spitzer final data release (DR4) (Evans+, 2003)

    Science.gov (United States)

    Evans, N. J., II; Allen, L. E.; Blake, G. A.; Boogert, A. C. A.; Bourke, T.; Harvey, P. M.; Kessler, J. E.; Koerner, D. W.; Lee, C. W.; Mundy, L. G.; Myers, P. C.; Padgett, D. L.; Pontoppidan, K.; Sargent, A. I.; Stapelfeldt, K. R.; van Dishoeck, E. F.; Young, C. H.; Young, K. E.

    2014-05-01

    This is the final delivery (DR4, Fall 2006 and Fall 2007) of the Spitzer Space Telescope "From Molecular Cores to Planet-Forming Disks" (c2d) Legacy Project. The data are also available as Enhanced Products from the Spitzer Science Center (SSC). c2d has delivered 867 catalogs. IRSA has merged these delivered catalogs into four groups - Clouds, Off-Cloud, Cores, Stars - and serves them through the general catalog search engine Gator. Many of the delivered catalogs, images and spectra are accessible through IRSA's general search service, Atlas. As a service to its users, the CDS has downloaded a dataset containing most of the c2d data (but not all columns) from the IRSA archive. The individual catalogs are listed below: C2D Fall '07 Full CLOUDS Catalog (CHA_II, LUP, OPH, PER, SER) C2D Fall '07 High Reliability (HREL) CLOUDS Catalog (CHA_II, LUP, OPH, PER, SER) C2D Fall '07 candidate Young Stellar Objects (YSO) CLOUDS Catalog (CHA_II, LUP, OPH, PER, SER) C2D Fall '07 Full OFF-CLOUD Catalog (CHA_II, LUP, OPH, PER, SER) C2D Fall '07 candidate Young Stellar Objects (YSO) OFF-CLOUD Catalog (CHA_II, LUP, OPH, PER, SER) C2D Fall '07 Full CORES Catalog C2D Fall '07 candidate Young Stellar Objects (YSO) CORES Catalog C2D Fall '07 Full STARS Catalog C2D Fall '07 candidate Young Stellar Objects (YSO) STARS Catalog These tables have been merged into a single table at CDS. All three SIRTF instruments (Infrared Array Camera [IRAC], Multiband Imaging Photometer for SIRTF [MIPS], and Infrared Spectrograph [IRS]) were used to observe sources that span the evolutionary sequence from molecular cores to protoplanetary disks, encompassing a wide range of cloud masses, stellar masses, and star-forming environments. (1 data file).

  14. A new Density Functional Theory (DFT) based method for supporting the assignment of vibrational signatures of mannan and cellulose—Analysis of palm kernel cake hydrolysis by ATR-FT-IR spectroscopy as a case study

    DEFF Research Database (Denmark)

    Barsberg, Søren Talbro; Sanadi, Anand Ramesh; Jørgensen, Henning

    2011-01-01

    method for polysaccharide IR band assignments. Palm kernel cake is enzymatically hydrolyzed and fermented, which targets cellulose and mannan in particular. The DFT method helps to identify their spectral changes and gives new knowledge on their spectral signatures. This method thus provides...

  15. Face recognition method based on 2D-PCA and 2D-LDA%基于2D-PCA和2D-LDA的人脸识别方法

    Institute of Scientific and Technical Information of China (English)

    温福喜; 刘宏伟

    2007-01-01

    提出了基于2D-PCA、2D-LDA两种特征采用融合分类器的人脸识别方法.首先提取人脸图像的2D-PCA和2D-LDA特征,对不同特征在决策层对分类器进行融合.在ORL人脸库上的试验结果表明,分类器决策层融合方法在识别性能上优于2D-PCA和2D-LDA,更具有鲁棒性.

  16. Analysis list: Kmt2d [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Kmt2d Adipocyte,Pluripotent stem cell + mm9 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/target/Kmt2d....1.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/target/Kmt2d.5.tsv http://dbarchiv...e.biosciencedbc.jp/kyushu-u/mm9/target/Kmt2d.10.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/colo/Kmt2d....Adipocyte.tsv,http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/colo/Kmt2d.Pluripo

  17. Analysis list: KMT2D [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available KMT2D Blood,Digestive tract + hg19 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/target/KM...T2D.1.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/target/KMT2D.5.tsv http://dbarchive.biosc...iencedbc.jp/kyushu-u/hg19/target/KMT2D.10.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/colo/KMT2D.Blo...od.tsv,http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/colo/KMT2D.Digestive_tract

  18. ARTIFICIAL NEURAL-NETWORK PREDICTIONS OF URINARY CALCULUS COMPOSITIONS ANALYZED WITH INFRARED-SPECTROSCOPY

    NARCIS (Netherlands)

    VOLMER, M; WOLTHERS, BG; METTING, HJ; DEHAAN, THY; COENEGRACHT, PMJ; VANDERSLIK, W

    1994-01-01

    Infrared (IR) spectroscopy is used to analyze urinary calculus (renal stone) constituents. However, interpretation of IR spectra for quantifying urinary calculus constituents in mixtures is difficult, requiring expert knowledge by trained technicians. In our laboratory IR spectra of unknown calculi

  19. 2D manifold-independent spinfoam theory

    International Nuclear Information System (INIS)

    A number of background-independent quantization procedures have recently been employed in 4D nonperturbative quantum gravity. We investigate and illustrate these techniques and their relation in the context of a simple 2D topological theory. We discuss canonical quantization, loop or spin network states, path integral quantization over a discretization of the manifold, spin foam formulation and the fully background-independent definition of the theory using an auxiliary field theory on a group manifold. While several of these techniques have already been applied to this theory by Witten, the last one is novel: it allows us to give a precise meaning to the sum over topologies, and to compute background-independent and, in fact, 'manifold-independent' transition amplitudes. These transition amplitudes play the role of Wightman functions of the theory. They are physical observable quantities, and the canonical structure of the theory can be reconstructed from them via a C* algebraic GNS construction. We expect an analogous structure to be relevant in 4D quantum gravity

  20. Ion Transport in 2-D Graphene Nanochannels

    Science.gov (United States)

    Xie, Quan; Foo, Elbert; Duan, Chuanhua

    2015-11-01

    Graphene membranes have recently attracted wide attention due to its great potential in water desalination and selective molecular sieving. Further developments of these membranes, including enhancing their mass transport rate and/or molecular selectivity, rely on the understanding of fundamental transport mechanisms through graphene membranes, which has not been studied experimentally before due to fabrication and measurement difficulties. Herein we report the fabrication of the basic constituent of graphene membranes, i.e. 2-D single graphene nanochannels (GNCs) and the study of ion transport in these channels. A modified bonding technique was developed to form GNCs with well-defined geometry and uniform channel height. Ion transport in such GNCs was studied using DC conductance measurement. Our preliminary results showed that the ion transport in GNCs is still governed by surface charge at low concentrations (10-6M to 10-4M). However, GNCs exhibits much higher ionic conductances than silica nanochannels with the same geometries in the surface-charge-governed regime. This conductance enhancement can be attributed to the pre-accumulation of charges on graphene surfaces. The work is supported by the Faculty Startup Fund (Boston University, USA).