WorldWideScience

Sample records for chemical preparation

  1. Optically monitored wet chemical preparation of SEIRA active metallic nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Enders, Dominik; Nakayama, Tomonobu [National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki, 305-0044 (Japan); Nanoscale Quantum Conductor Array Project, ICORP, JST, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012 (Japan); Nagao, Tadaaki; Aono, Masakazu [National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki, 305-0044 (Japan); Nanoscale Quantum Conductor Array Project, ICORP, JST, 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012 (Japan); WPI Center for Materials Nanoarchitectonics (MANA), 1-1 Namiki, Tsukuba, Ibaraki, 305-0044 (Japan)

    2008-07-01

    The use of wet chemical methods for the preparation of surface enhanced infrared absorption (SEIRA) active nanostructures has gained much interest in the last years because of its easiness, simplicity, and the low time consumption compared to the known ultra high vacuum based methods. We present a two-step wet-chemical preparation method of plasmonic SEIRA active nanostructures. While in the first step spherical Au nanoparticles are deposited on the SiO{sub 2}/Si surface, these nanoparticles are grown in the second step to form elongated tabular islands close to the percolation threshold. In situ monitoring of the preparation process by IR spectroscopy ensures the control of film morphology during the preparation process and enables the reproducible fabrication of highly sensitive SEIRA films. A comparison of our Au films with SEIRA inactive Au films shows, that in IR spectra of octadecanethiol, the CH stretching vibrational peaks are enhanced by several orders of magnitude.

  2. Chemical flowsheet conditions for preparing urania spheres by internal gelation

    International Nuclear Information System (INIS)

    Small, ceramic urania spheres can be prepared for use as nuclear fuel by internal chemical gelation of uranyl nitrate solution droplets. Decomposition of hexamethylenetetramine (HMTA) dissolved in the uranyl nitrate solution releases ammonia to precipitate hydrated UO3. Previously established flowsheet conditions have been improved and modified at ORNL and have been applied to prepare dense UO2 spheres with average diameters of 1200, 300, and 30 μm

  3. Exploring Simulator Use in the Preparation of Chemical Engineers

    Science.gov (United States)

    Yerrick, Randy; Lund, Carl; Lee, Yonghee

    2013-01-01

    In this manuscript, we report the impact of students' usage of a simulator in the preparation of chemical engineers. This case study was conducted using content pretest and posttests, survey questionnaires, interviews, classroom observations, and an analysis of students' written response to design problems. Results showed the use of simulator was…

  4. Compaction of Chemically Prepared Amorphous Fe-B nanoparticles

    DEFF Research Database (Denmark)

    Hendriksen, P.V.; Bødker, Franz; Mørup, Steen;

    1997-01-01

    We report on attempts to compact chemically prepared amorphous iron-boron particles. The praticles have a size of about 100 nm and are pyrophoric. We have made a special die for uniaxial pressing in which the compaction can be performed at elevated temperature without exposing the powder to air. ...

  5. Preparation of activated carbon by chemical activation under vacuum.

    Science.gov (United States)

    Juan, Yang; Ke-Qiang, Qiu

    2009-05-01

    Activated carbons especially used for gaseous adsorption were prepared from Chinesefir sawdust by zinc chloride activation under vacuum condition. The micropore structure, adsorption properties, and surface morphology of activated carbons obtained under atmosphere and vacuum were investigated. The prepared activated carbons were characterized by SEM, FTIR, and nitrogen adsorption. It was found that the structure of the starting material is kept after activation. The activated carbon prepared under vacuum exhibited higher values of the BET surface area (up to 1079 m2 g(-1)) and total pore volume (up to 0.5665 cm3 g(-1)) than those of the activated carbon obtained under atmosphere. This was attributed to the effect of vacuum condition that reduces oxygen in the system and limits the secondary reaction of the organic vapor. The prepared activated carbon has well-developed microstructure and high microporosity. According to the data obtained, Chinese fir sawdust is a suitable precursor for activated carbon preparation. The obtained activated carbon could be used as a low-cost adsorbent with favorable surface properties. Compared with the traditional chemical activation, vacuum condition demands less energy consumption, simultaneity, and biomass-oil is collected in the procedure more conveniently. FTIR analysis showed that heat treatment would result in the aromatization of the carbon structure. PMID:19534162

  6. Preparation and physico-chemical evaluation of kshiramandura.

    Science.gov (United States)

    Jadar, P G; Jagadeesh, M S

    2010-04-01

    Mandura (Iron rust) is known by names lohkitta, malayas, ayomala, meaning waste of iron. Among different formulations prescribed for Parinamashoola (Peptic ulcer), in Ayurvedic classics Kshiramandura (Preparation of Iron rust in Milk) is one. Ancient authorities have given similar recipes of Mandura and these medicines are being successfully administered in the management of Peptic ulcer. In Parinamashoola (Peptic ulcer), Acharya Chakradatta mentioned Kshiramandura, as a formulation prepared by taking 384gms of Mandura Bhasma (Incinerated Iron rust), 3 Kg 73 gm of cow's urine and 768gms of cow's milk, boiled and administered in a dose of 500mg. To establish Physical and Chemical factors present in Mandura before and after purification and incineration, the preparation ofKshira mandura was attempted by adopting Quantitative and Qualitative methods. The drugwas identified by the qualities as described in the classics, viz., unctuous, heavy, hard and black in color and absence of hollow space. Mandura was heated in burning charcoal (600-800° c) and dipped in 5 liters of Cow's urine. This process was repeated 7 times, till the Mandura broke. This purified Mandura was then powdered and triturated with decoction ofTerminalia chebula, Terminalia belerica and Emblica officinalis (Triphala kashaya). Thereafter pellets were prepared and dried. The pellets were then sealed in crucibles and heated 30 times in a special type of furnace with temperature of 1000°c (Gajaputa method) to incinerate Mandura and prepare its ash (Bhasma). Cow's urine and milk were added to this Mandura Bhasma and Kshiramandura was prepared. When analyzed it showed 68.3 5% Ferric oxide, 0.66%MgCO(3) and 1.32% CaCO(3). PMID:22557361

  7. Radiation chemical route for preparation of metal nanoparticles

    International Nuclear Information System (INIS)

    Nanoparticles show properties that are neither seen in the bulk or at atomic level. The unusual properties are governed by quantum size effect. Due to this various methodologies have been endeavored to control the size of the particles. In the present work we show the use of two complimentary techniques (radiation and photo) to synthesize and control the size of the metal particles. In-situ synthesis of fine silver, thallium and cadmium particles has been carried out by gamma-irradiation and electron pulse irradiation at room temperature in the pre-organized gel of polyacrylamide or cyclodextrin cavity. The role of generation of nuclei in high concentrations in stabilization of metal nanoparticles in hydrophobic cavity is shown. Similarly the importance of entrapment of metal ions in the polymer matrix during its formation is highlighted. The work is further extended to exploit the microemulsion droplets for stabilization of Cd nanoparticles. Utility of pulse radiolysis in probing the mechanism of the formation of metal nanoparticles is also shown. Ultrafast laser pulses were employed to control the morphology of the pre-prepared Pt nanoparticles. The changes in reduction of shape and size are considered to occur through melting and vaporization of the nanoparticles. Pt nanoparticles were coated on the inner walls of the tubular pyrex reactor and tested for their catalytic activity for oxidation of CO. It was observed that Pt nanoparticles prepared in the presence of a stabilizer (gelatin) showed a higher tendency to adhere to the inner walls of the pyrex reactor as compared to that prepared in the presence of silica nanoparticles. The catalyst was found to be active at ≥150 degree C giving CO2. Chemically reduced Pt nanoparticles stabilized on silica nanoparticles gave ∼7% CO conversion per hr. However, radiolytically prepared Pt nanoaprticles stabilized by gelatin gave ∼10% conversion per hr. The data indicates that catalytic oxidation of CO takes place by

  8. A new fluorescent particle prepared by chemical stabilized phycobilisome

    Institute of Scientific and Technical Information of China (English)

    Min Chen; Guo Ping Ma; Li Sun

    2009-01-01

    Natural phycobilisomes (PBSs) were isolated and purified from a red macroalga, Polysiphonia urceolata, by multi-step of sucrose gradient centrifugation, and were chemically stabilized by small molecule cross-linker formaldehyde. The stabilized PBSs showed similar absorption and fluorescent properties at room temperature compared to natural PBSs and kept a steady F672/F580 value during more than 3 months of storage in 0.45 mol/L phosphate buffer (pH 6.8) or at low temperature at 77 K. The stabilized PBS migrated as a single band at mild PAGE and in 14-18 h of sucrose gradient centdfiagation. All these characters indicated that the stabilized PBSs were stable, soluble, homogenous fluorescent particles with favorable spectroscopic features prepared under present conditions.

  9. Tetragonal zirconia: Wet chemical preparation, mechanical and electrical properties

    NARCIS (Netherlands)

    Keizer, K.; Hemert, van M.; Graaf, van de M.A.C.G.; Burggraaf, A.J.

    1985-01-01

    Yttria-stabilized zirconia powders were prepared in the composition range of 3 to 13 at% yttria. The hydrolysis-gel precipitation technique was used, starting from metal alkoxides or chlorides. In the composition range between 5 and 10 at% yttria, the materials sintered at 1250°C have a fully tetrag

  10. Calcium phosphate bioceramics prepared from wet chemically precipitated powders

    Directory of Open Access Journals (Sweden)

    Kristine Salma

    2010-03-01

    Full Text Available In this work calcium phosphates were synthesized by modified wet chemical precipitation route. Contrary to the conventional chemical precipitation route calcium hydroxide was homogenized with planetary mill. Milling calcium oxide and water in planetary ball mill as a first step of synthesis provides a highly dispersed calcium hydroxide suspension. The aim of this work was to study the influence of main processing parameters of wet chemical precipitation synthesis product and to control the morphology, phase and functional group composition and, consequently, thermal stability and microstructure of calcium phosphate bioceramics after thermal treatment. The results showed that it is possible to obtain calcium phosphates with different and reproducible phase compositions after thermal processing (hydroxyapatite [HAp], β-tricalcium phosphate [β-TCP] and HAp/β-TCP by modified wet-chemical precipitation route. The β-TCP phase content in sintered bioceramics samples is found to be highly dependent on the changes in technological parameters and it can be controlled with ending pH, synthesis temperature and thermal treatment. Pure, crystalline and highly thermally stable (up to 1300°C HAp bioceramics with homogenous grainy microstructure, grain size up to 200–250 nm and high open porosity can be successfully obtained by powder synthesized at elevated synthesis temperature of 70°C and stabilizing ending pH at 9.

  11. High index of refraction films for dielectric mirrors prepared by metal-organic chemical vapor deposition

    International Nuclear Information System (INIS)

    A wide variety of metal oxides with high index of refraction can be prepared by Metal-Organic Chemical Vapor Deposition. We present some recent optical and laser damage results on oxide films prepared by MOCVD which could be used in a multilayer structure for highly reflecting (HR) dielectric mirror applications. The method of preparation affects both optical properties and laser damage threshold. 10 refs., 8 figs., 4 tabs

  12. Sediment losses from forest management: mechanical vs. chemical site preparation after clearcutting

    Energy Technology Data Exchange (ETDEWEB)

    Beasley, R.S.; Granillo, A.B.; Zillmer, V.

    The comparative effects of mechanical and chemical site preparation water yields and sediment losses following forest clearcutting were evaluated over a 4-yr period in the Athens Plateau area of southwestern Arkansas. After 1 yr of pretreatment measurements, three forested water sheds were clearcut and the residual vegetation and debris were sheared and windrowed but not burned. Three watersheds were clearcut in a similar manner, but received chemical site preparation. Residual trees on two watersheds were injected with 2-4, D amine; the third watershed was aerially sprayed with a mixture of Tordon (active ingredient: picloram (4-amino-3,5,6-trichloropicoline acid)) and Garlon (active ingredient; triclopyr (3,5,6-trichloro-2-pyridinyloxyacetic acid)). Three additional watersheds were left undisturbed for controls. Mean annual sediment losses on the mechanically, site prepared watersheds during the first posttreatment year were significantly higher than those from either the chemically site prepared watersheds or controls. Chemical site preparation did not significantly increase sediment losses. Although 2nd yr losses for the mechanical site preparation and control treatments doubled over 1st-yr levels, no significant treatment effect was detected for either site preparation treatment. Third-year losses decreased below 1st-yr losses for all treatments but not to pretreatment year levels. The relatively sharp declines in sediment losses during the third posttreatment year were attributed to rapid regrowth of natural vegetation on the sites.

  13. Preparation and characterization of a chemically sulfated cashew gum polysaccharide

    Energy Technology Data Exchange (ETDEWEB)

    Moura Neto, Erico de; Maciel, Jeanny da S.; Cunha, Pablyana L. R.; Paula, Regina Celia M. de; Feitosa, Judith P.A., E-mail: judith@dqoi.ufc.br [Departamento de Quimica Organica e Inorganica, Universidade Federal do Ceara, Fortaleza (Brazil)

    2011-09-15

    Cashew gum (CG) was sulfated in pyridine:formamide using chlorosulfonic acid as the reagent. Confirmation of sulfation was obtained by Fourier transform infrared (FTIR) spectroscopy through the presence of an asymmetrical S=O stretching vibration at 1259 cm{sup -1}. The degrees of substitution were 0.02, 0.24 and 0.88 determined from the sulfur percentage. 1D and 2D nuclear magnetic resonance (NMR) data showed that the sulfation occurred at primary carbons. An increase of at least 4% of the solution viscosity was observed due to sulfation. The thermal gravimetric curves (TGA) indicate that the derivatives are stable up to ca. 200 deg C. The sulfated CG is compared to carboxymethylated CG in order to verify the possibility of the use of the former in the preparation of polyelectrolyte complexes; the latter is already being used for this application. (author)

  14. Chemical and electrical properties of LSM cathodes prepared by mechanosynthesis

    Science.gov (United States)

    Moriche, R.; Marrero-López, D.; Gotor, F. J.; Sayagués, M. J.

    2014-04-01

    Mechanosynthesis of La1-xSrxMnO3 (x = 0, 0.25, 0.5, 0.75 and 1) was carried out at room temperature from stoichiometric mixtures of La2O3, Mn2O3 and SrO, obtaining monophasic powders with the perovskite structure. Physical properties of these materials and their chemical compatibility with the electrolyte yttria stabilized zirconia (YSZ), which depend strongly on the La/Sr ratio, were evaluated to corroborate availability to be implemented as cathode material in solid oxide fuel cells (SOFCs). Electrical conductivity values in air ranged between 100 and 400 S cm-1 in the temperature range of 25-850 °C. Samples presented low reactivity with YSZ in the working temperature range (600-1000 °C) maintaining the grain size small enough to preserve the catalytic activity for oxygen reduction.

  15. Advanced titania buffer layer architectures prepared by chemical solution deposition

    Science.gov (United States)

    Kunert, J.; Bäcker, M.; Brunkahl, O.; Wesolowski, D.; Edney, C.; Clem, P.; Thomas, N.; Liersch, A.

    2011-08-01

    Chemical solution deposition (CSD) was used to grow high-quality (100) oriented films of SrTiO3 (STO) on CSD CaTiO3 (CTO), Ba0.1Ca0.9TiO3 (BCT) and STO seed and template layers. These template films bridge the lattice misfit between STO and the nickel-tungsten (NiW) substrate, assisting in dense growth of textured STO. Additional niobium (Nb) doping of the STO buffer layer reduces oxygen diffusion which is necessary to avoid undesired oxidation of the NiW. The investigated templates offer suitable alternatives to established standard buffer systems like La2Zr2O7 (LZO) and CeO2 for coated conductors.

  16. Phytotoxicity of Ag nanoparticles prepared by biogenic and chemical methods

    Science.gov (United States)

    Choudhury, Rupasree; Majumder, Manna; Roy, Dijendra Nath; Basumallick, Srijita; Misra, Tarun Kumar

    2016-06-01

    Silver nanoparticles (Ag NPs) are now widely used as antibacterial and antifungal materials in different consumer products. We report here the preparation of Ag NPs by neem leaves extract ( Azadirachta) reduction and trisodium citrate-sodium borohydride reduction methods, and study of their phytotoxicity. The nanoparticles were characterized by UV-Vis spectroscopy, FTIR, and atomic force microscopy (AFM) techniques. Both neem-coated and citrate-coated Ag NPs exhibit surface plasmon around 400 nm, and their average sizes measured by AFM are about 100 and 20 nm, respectively. Antibacterial and antifungal activities of these nanomaterials have been studied by simple pea seed germination and disk diffusion methods. It has been observed from the growth of root and shoot, citrate-coated Ag NPs significantly affect seedling growth, but neem-coated Ag NPs exhibit somehow mild toxicity toward germination process due to the nutrient supplements from neem. On the other hand, antifungal activity of neem-coated Ag NPs has been found much higher than that of citrate-coated Ag NPs due to the combined effects of antifungal activity of neem and Ag NPs. Present research primarily indicates a possible application of neem-coated Ag NPs as a potential fungicide.

  17. Chemical Extraction Preparation of Delithiated Cathode Materials of Li-ion Battery

    Institute of Scientific and Technical Information of China (English)

    YAN Shijian; ZHANG Mingang; CHAI Yuesheng; TIAN Wenhuai

    2009-01-01

    A method of conventional chemical reaction to prepare delithiated cathode materials of Li-ion battery was introduced.The cathode material of Li-ion battery was mixed with oxidizing agent Na_2S_2O_8 in water solution,and the solution was stirred continuously to make the chemical re-action proceed sufficiently,then the reaction product was filtered and finally the insoluble delithiated cathode material was obtained.A series of tests were conducted to verify the composition,crystal structure and electrochemical property of the delithiated cathode materials were all desirable.This method overcomes the shortcomings of battery charging preparation and chemical extraction prepa-ration employing other oxidizing agents.

  18. Amorphous TM1−xBx alloy particles prepared by chemical reduction (invited)

    DEFF Research Database (Denmark)

    Linderoth, Søren; Mørup, Steen

    1991-01-01

    Amorphous transition-metal boron (TM-B) alloy particles can be prepared by chemical reduction of TM ions by borohydride in aqueous solutions. ln the last few years systematic studies of the parameters which control the composition, and, in turn, many of the properties of the alloy particles, have...... been performed and are reviewed in the present paper. The most important preparation parameters which influence the composition are the concentration of the borohydride solution and the pH of the TM salt solution. By controlling these parameters it is possible to prepare amorphous alloy samples...

  19. Preparation and Properties of Some Chemical and Electrochemical γ-MnO2

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Chemically prepared electrolytic γ-MnO2 and an electrodeposited MnO2 doped with Ce(III)were subjected to physicochemical studies. X-ray diffractometry, density measurements, chemical analysis and thermal analysis were used to determine the structure and chemical disorder present.The samples prepared chemically(CMD) or electrochemically (EMD) showed a variable amount of de Wolff disorder(Pr) and microtwinning (Tw). Manganese dioxide prepared in the presence of Ce(III) showed appreciable decrease in de Wolff defect and a large amount of microtwinning. Thermal analysis showed a loss of weight due to the physically adsorbed and the structural(OH)water, from which the activation energy was calculated. Chemical composition and formulae calculated on the bases of cation vacancy model, cleared that Ce(III)-doped sample has a remarkable increase in the vacancies population associated with higher structural water content. This leads to lower activation energy of water release, and consequently it is supposed to acquire higher electrochemical activity.

  20. [Composition, physico-chemical properties and molecular superstructure of dietary fiber preparations of the cellan type].

    Science.gov (United States)

    Dongowski, G; Frigge, K; Zenke, I

    1995-07-01

    Dietary fiber preparations of "cellan" type were prepared from apples, white cabbage, sugar beet pulp, soy hulls and wheat bran by treatment with amylolytic and proteolytic enzymes as well as by chemical extractions. Scanning electron microscopic examinations show different morphological structures of the preparations and a high maintenance of native biomolecular superstructure. The content of pectin, protein, polysaccharide-hexoses and -pentoses and the composition of monosaccharides (also after their treatment with 4 or 8% sodium hydroxide) were determined. The cellans possess waterbinding capacities (WBC) between 25 g H2O/g and waterholding capacities between 50 g H2O/g. The WBC is related to the internal surface; it diminishes after treatment with NaOH. The interactions between the cellans and the adsorbed water were characterized by NMR-spin-lattice relaxation time T1. The molecular mobility increases as the water content grows. The T1-values of dried cellans decreased with increasing degree of moisture before drying. The supermolecular structure is comparatively disordered. Only in case of soy cellan a crystalline cellulose-I-modification could be identified by X-ray-diffraction pattern, esp. after NaOH treatment. The low degree of order of cellans was observed in the 13C-NMR spectra, too. Only the soy hull preparation resulted in a spectrum corresponding to well-ordered cellulose. The botanic source has an essential influence on the physico-chemical properties of dietary fiber preparations of cellan type.

  1. Textural Development of Activated Carbon Prepared from Recycled PET with Different Chemical Activation Agents

    OpenAIRE

    Cansado, Isabel; Ribeiro Carrott, Manuela; Carrott, Peter; Mourão, Paulo

    2008-01-01

    In this work a series of microporous activated carbons, with different burn offs, was prepared from recycled PET provided by Selenis (Portalegre-Portugal). These AC were prepared by chemical activation with KOH, NaOH and H3PO4, and carbonised under a N2 flow of 85cm3min-1 between 873 and 1273K. The carbonised samples were then cooled and successively washed until the washable solutions achieved a pH around 7.0, afterwards these were dried at 110ºC. All adsorbents were characterised by the ads...

  2. Preparation and characterization of ZnS thin films by the chemical bath deposition method

    Energy Technology Data Exchange (ETDEWEB)

    Iwashita, Taisuke [Department of Electrical Engineering, Faculty of Engineering, Tokyo University of Science 1-14-6 Kudankita, Chiyoda, Tokyo 102-0073 (Japan); Ando, Shizutoshi, E-mail: ando_shi@rs.kagu.tus.ac.jp [Department of Electrical Engineering, Faculty of Engineering, Tokyo University of Science 1-14-6 Kudankita, Chiyoda, Tokyo 102-0073 (Japan); Research Institute for Science and Technology, Advanced Device Laboratories (ADL), Tokyo University of Science, 1-3 Kagurazaka, Shinjuku, Tokyo 162-8601 (Japan); Research Institute for Science and Technology, Photovoltaic Science and Technology Research Division, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku, Tokyo 162-8601 (Japan)

    2012-10-01

    ZnS thin films prepared on quartz substrates by the chemical bath deposition (CBD) method with three type temperature profile processes have been investigated by X-ray diffraction, scanning electron microscope, energy dispersive X-ray analysis and light transmission. One is a 1-step growth process, and the other is 2-steps growth and self-catalyst growth processes. The surface morphology of CBD-ZnS thin films prepared by the CBD method with the self-catalyst growth process is flat and smooth compared with that prepared by the 1-step and 2-steps growth processes. The self-catalyst growth process in order to prepare the particles of ZnS as initial nucleus layer was useful for improvement in crystallinity of ZnS thin films prepared by CBD. ZnS thin films prepared by CBD method with self-catalyst growth process can be expected for improvement in the conversion efficiency of Cu(InGa)Se{sub 2}-based thin film solar cells by using it for the buffer layer. - Highlights: Black-Right-Pointing-Pointer ZnS thin films were prepared by chemical bath deposition (CBD) method. Black-Right-Pointing-Pointer The crystallization of CBD-ZnS films was further improved. Black-Right-Pointing-Pointer The crystallinity of CBD-ZnS thin films is dependent on the zinc source material. Black-Right-Pointing-Pointer Self-catalyst growth process is useful for the growth of thin films by CBD method. Black-Right-Pointing-Pointer It is expected to improve the conversion efficiency of CuIn{sub 1-x}Ga{sub x}Se{sub 2} solar cells.

  3. Influence of particle size and preparation methods on the physical and chemical stability of amorphous simvastatin

    DEFF Research Database (Denmark)

    Zhang, Fang; Aaltonen, Jaakko; Tian, Fang;

    2009-01-01

    This study investigated the factors influencing the stability of amorphous simvastatin. Quench-cooled amorphous simvastatin in two particle size ranges, 150-180 microm (QC-big) and ... stability were investigated. Physical stability (crystallization) of amorphous simvastatin stored at two conditions was monitored by X-ray powder diffractometry (XRPD) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). Assessment of enthalpy relaxation of amorphous forms was conducted...... using DSC in order to link the physical and chemical stability with molecular mobility. Chemical stability was studied with high-performance liquid chromatography (HPLC). Results obtained from the current study revealed that the solubility of amorphous forms prepared by both methods was enhanced...

  4. Preparing Federal Coordinating Officers (FCOs) to operate in Chemical, Biological, Radiological, and Nuclear (CBRN) environments

    OpenAIRE

    Russell, Tony.

    2008-01-01

    CHDS State/Local In this thesis the Federal Emergency Management Agency's (FEMA) Federal Coordinating Officer (FCO) function is examined as it relates to Chemical, Biological, Radiological and Nuclear (CBRN) operations. It is suggested that targeted changes can be made to ensure the FCOs are better prepared to manage the additional complexities of a CBRN environment. The changes include addressing the FCOs from the systems approach- internally to improve the FCO personal and professio...

  5. Preparation and Characterization of Chitosan/Agar Blended Films: Part 1. Chemical Structure and Morphology

    OpenAIRE

    Esam A. El-Hefian; Mohamed Mahmoud NASEF; Yahaya, Abdul Hamid

    2012-01-01

    Chitosan/agar (CS/AG) films were prepared by blending different proportions of chitosan and agar (considering chitosan as the main component) in solution forms. The chemical structure and the morphology of the obtained blended films were investigated using Fourier transform infrared (FTIR) and field emission scanning electron microscope (FESEM). It was revealed that chitosan and agar form a highly compatible blend and their films displayed homogenous and smooth surface properties compared to ...

  6. Polyoxometalate based soft chemical route for preparation of Pt nanorods and self-assemblies

    Indian Academy of Sciences (India)

    S Shanmugam; B Viswanathan; T K Varadarajan

    2005-10-01

    A soft chemical route is described for the preparation of platinum nanorods and self-assemblies over photochemically reduced polyoxometalate (silicotungstate) containing composite films. Transmission electron microscopy shows that the diameters of the platinum nanorods are around 55–60 nm. The formation of platinum nanorods on solid–liquid interface reactions was explained on the basis of single site growth mechanism and diffusion limitation aggregation process.

  7. The Electrochemical Characteristics of Hybrid Capacitor Prepared by Chemical Activation of NaOH

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jeong Eun; Bae, Ga Yeong; Yang, Jeong Min; Lee, Jong Dae [Chungbuk National Univ., Chungju (Korea, Republic of)

    2013-06-15

    Active carbons with high specific surface area and micro pore structure were prepared from the coconut shell char using the chemical activation method of NaOH. The preparation process has been optimized through the analysis of experimental variables such as activating chemical agents to char ratio and the flow rate of gas during carbonization. The active carbons with the surface area (2,481m{sup 2}/g) and mean pore size (2.32 nm) were obtained by chemical activation with NaOH. The electrochemical performances of hybrid capacitor were investigated using LiMn{sub 2}O{sub 4}, LiCoO{sub 2} as the positive electrode and prepared active carbon as the negative electrode. The electrochemical behaviors of hybrid capacitor using organic electrolytes (LiPF{sub 6}, TEABF{sub 4}) were characterized by constant current charge/discharge, cyclic voltammetry, cycle and leakage tests. The hybrid capacitor using LiMn{sub 2}O{sub 4}/AC electrodes had better capacitance than other hybrid systems and was able to deliver a specific energy as high as 131 Wh/kg at a specific power of 1,448 W/kg.

  8. Research and Development Aspects on Chemical Preparation Techniques of Photoanodes for Dye Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Nilofar Asim

    2014-01-01

    Full Text Available The importance of dye sensitized solar cells (DSSCs as a low-cost and environmentally friendly photovoltaic (PV technology has prompted many researchers to improve its efficiency and durability. The realization of these goals is impossible without taking into account the importance of the materials in DSSCs, so the focus on the preparation/deposition methods is essential. These methods can be either chemical or physical. In this study, the chemical applied methods that utilize chemical reaction to synthesize and deposit the materials are covered and categorized according to their gas phase and liquid phase precursors. Film processing techniques that can be used to enhance the materials' properties postpreparation are also included for further evaluation in this study. However, there is a variety of consideration, and certain criteria must be taken into account when selecting a specific deposition method, due to the fact that the fabrication conditions vary and are unoptimized.

  9. Chemical Properties of Carbon Nanotubes Prepared Using Camphoric Carbon by Thermal-CVD

    International Nuclear Information System (INIS)

    Chemical properties and surface study on the influence of starting carbon materials by using thermal chemical vapor deposition (Thermal-CVD) to produced carbon nanotubes (CNTs) is investigated. The CNTs derived from camphor were synthesized as the precursor material due to low sublimation temperature. The major parameters are also evaluated in order to obtain high-yield and high-quality CNTs. The prepared CNTs are examined using field emission scanning electron microscopy (FESEM) to determine the microstructure of nanocarbons. The FESEM investigation of the CNTs formed on the support catalysts provides evidence that camphor is suitable as a precursor material for nanotubes formation. The chemical properties of the CNTs were conducted using FTIR spectroscopy and PXRD analysis. The high-temperature graphitization process induced by the Thermal-CVD enables the hydrocarbons to act as carbon sources and changes the aromatic species into the layered graphite structure of CNTs.

  10. Electroluminescence and photoluminescence of conjugated polymer films prepared by plasma enhanced chemical vapor deposition of naphthalene

    CERN Document Server

    Rajabi, Mojtaaba; Firouzjah, Marzieh Abbasi; Hosseini, Seyed Iman; Shokri, Babak

    2012-01-01

    Polymer light-emitting devices were fabricated utilizing plasma polymerized thin films as emissive layers. These conjugated polymer films were prepared by RF Plasma Enhanced Chemical Vapor Deposition (PECVD) using naphthalene as monomer. The effect of different applied powers on the chemical structure and optical properties of the conjugated polymers was investigated. The fabricated devices with structure of ITO/PEDOT:PSS/ plasma polymerized Naphthalene/Alq3/Al showed broadband Electroluminescence (EL) emission peaks with center at 535-550 nm. Using different structural and optical tests, connection between polymers chemical structure and optical properties under different plasma powers has been studied. Fourier transform infrared (FTIR) and Raman spectroscopies confirmed that a conjugated polymer film with a 3-D cross-linked network was developed. By increasing the power, products tended to form as highly cross-linked polymer films. Photoluminescence (PL) spectra of plasma polymers showed different excimerc ...

  11. Chemical Properties of Carbon Nanotubes Prepared Using Camphoric Carbon by Thermal-CVD

    Science.gov (United States)

    Azira, A. A.; Rusop, M.

    2010-03-01

    Chemical properties and surface study on the influence of starting carbon materials by using thermal chemical vapor deposition (Thermal-CVD) to produced carbon nanotubes (CNTs) is investigated. The CNTs derived from camphor were synthesized as the precursor material due to low sublimation temperature. The major parameters are also evaluated in order to obtain high-yield and high-quality CNTs. The prepared CNTs are examined using field emission scanning electron microscopy (FESEM) to determine the microstructure of nanocarbons. The FESEM investigation of the CNTs formed on the support catalysts provides evidence that camphor is suitable as a precursor material for nanotubes formation. The chemical properties of the CNTs were conducted using FTIR spectroscopy and PXRD analysis. The high-temperature graphitization process induced by the Thermal-CVD enables the hydrocarbons to act as carbon sources and changes the aromatic species into the layered graphite structure of CNTs.

  12. Dielectric behaviour of MgFe2O4 prepared from chemically beneficiated iron ore rejects

    Indian Academy of Sciences (India)

    K S Rane; V M S Verenkar; P Y Sawant

    2001-06-01

    Chemically beneficiated high silica/alumina iron ore rejects (27–76% Fe2O3) were used to synthesize iron oxides of purity 96–98% with SiO2/Al2O3 ratio reduced to 0.03. The major impurities on chemical beneficiations were Al, Si, and Mn in the range 2–3%. A 99.73% purity Fe2O3 was also prepared by solvent extraction method using methyl isobutyl ketone (MIBK) from the acid extracts of the ore rejects. The magnesium ferrite, MgFe2O4, prepared from these synthetic iron oxides showed high resistivity of ∼ 108 ohm cm. All ferrites showed saturation magnetization, 4s, in the narrow range of 900–1200 Gauss and the Curie temperature, c, of all these fell within a small limit of 670 ± 30 K. All ferrites had low dielectric constants ('), 12–15, and low dielectric loss, tan , which decreased with the increase in frequency indicating a normal dielectric dispersion found in ferrites. The presence of insignificant amount of polarizable Fe2+ ions can be attributed to their high resistances and low dielectric constants. Impurities inherent in the samples had no marked influence on the electrical properties of the ferrites prepared from the iron ore rejects, suggesting the possibility of formation of ferrite of constant composition, MgFe2O4, of low magnetic and dielectric losses at lower temperatures of 1000°C by ceramic technique.

  13. Characteristics of Barium Hexaferrite Nanoparticles Prepared by Temperature-Controlled Chemical Coprecipitation

    Energy Technology Data Exchange (ETDEWEB)

    Kwak, Jun Young; Lee, Choong Sub; Kim, Don; Kim, Yeong Il [Pukyong National Univ., Busan (Korea, Republic of)

    2012-10-15

    Ba-ferrite (BaFe{sub 12}O{sub 19}) nanoparticles were synthesized by chemical coprecipitation method in an aqueous solution. The particle size and the crystallization temperature of the Ba-ferrite nanoparticles were controlled varying the precipitation temperature. The precipitate that was prepared at 0 .deg. C showed the crystal structure of Ba-ferrite in X-ray diffraction when it was calcined at the temperature above 580 .deg. C, whereas what was prepared at 50 .deg. C showed the crystallinity when it was calcined at the temperature higher than about 700 .deg. C. The particle sizes of the synthesized Ba-ferrite were in a range of about 20-30 nm when it was prepared by being precipitated at 0 .deg. C and calcined at 650 .deg. C. When the precipitation temperature increased, the particle size also increased even at the same calcination temperature. The magnetic properties of the Ba-ferrite nanoparticles were also controlled by the synthetic condition of precipitation and calcination temperature. The coercive force could be appreciably lowered without a loss of saturation magnetization when the Ba-ferrite nanoparticles were prepared by precipitation and calcination both at low temperatures.

  14. Preparation and characterization of nanostructured copper bismuth diselenide thin films from a chemical route

    Indian Academy of Sciences (India)

    R H Bari; L A Patil

    2010-12-01

    Thin films of copper bismuth diselenide were prepared by chemical bath deposition technique onto glass substrate below 60°C. The deposition parameters such as time, temperature of deposition and pH of the solution, were optimized. The set of films having different elemental compositions was prepared by varying Cu/Bi ratio from 0.13–1.74. Studies on structure, composition, morphology, optical absorption and electrical conductivity of the films were carried out and discussed. Characterization includes X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), energy dispersive X-ray analysis (EDAX), absorption spectroscopy, and electrical conductivity. The results are discussed and interpreted.

  15. Preparation of carbon nanotubes with different morphology by microwave plasma enhanced chemical vapour deposition

    Energy Technology Data Exchange (ETDEWEB)

    Duraia, El-Shazly M. [Suez Canal University, Faculty of Science, Physics Department, Ismailia (Egypt); Al-Farabi Kazakh National University, 71 Al-Farabi av., 050038 Almaty (Kazakhstan); Institute of Physics and Technology, Ibragimov Street 11, 050032 Almaty (Kazakhstan); Mansurov, Zulkhair [Al-Farabi Kazakh National University, 71 Al-Farabi av., 050038 Almaty (Kazakhstan); Tokmoldin, S.Zh. [Institute of Physics and Technology, Ibragimov Street 11, 050032 Almaty (Kazakhstan)

    2010-04-15

    In this work we present a part of our results about the preparation of carbon nanotube with different morphologies by using microwave plasma enhanced chemical vapour deposition MPECVD. Well aligned, curly, carbon nanosheets, coiled carbon sheets and carbon microcoils have been prepared. We have investigated the effect of the different growth condition parameters such as the growth temperature, pressure and the hydrogen to methane flow rate ratio on the morphology of the carbon nanotubes. The results showed that there is a great dependence of the morphology of carbon nanotubes on these parameters. The yield of the carbon microcoils was high when the growth temperature was 700 C. There is a linear relation between the growth rate and the methane to hydrogen ratio. The effect of the gas pressure on the CNTs was also studied. Our samples were investigated by scanning electron microscope and Raman spectroscopy (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  16. Studies on transparent spinel magnesium indium oxide thin films prepared by chemical spray pyrolysis

    International Nuclear Information System (INIS)

    Ternary semiconducting oxide compound magnesium indium oxide films (MgIn2O4), manifesting high transparency were prepared by metal organic chemical spray pyrolysis technique. Precursors prepared for various cationic ratios of Mg/In = 0.35, 0.40, 0.45 and 0.50 were thermally sprayed onto quartz substrates, decomposed at 450 deg. C and the spinel phase evolution was studied. X-ray diffraction, Rutherford backscattering and X-ray photoelectron spectroscopy studies have been conducted to confirm the formation of single-phase MgIn2O4 films with Mg/In ratio 0.50. From optical transmission studies, the observed optical band gaps varied from 3.18 to 3.86 eV (0.35 -5 S cm-1) and the Hall coefficient showed n-type electrical conduction and high carrier concentration (0.16 x 1020-0.89 x 17 cm-3)

  17. Near net shape forming processes for chemically prepared zinc oxide varistors.

    Energy Technology Data Exchange (ETDEWEB)

    Lockwood, Steven John; Voigt, James A.; Tuttle, Bruce Andrew; Bell, Nelson Simmons

    2005-01-01

    Chemically prepared zinc oxide powders are fabricated for the production of high aspect ratio varistor components. Colloidal processing in water was performed to reduce agglomerates to primary particles, form a high solids loading slurry, and prevent dopant migration. The milled and dispersed powder exhibited a viscoelastic to elastic behavioral transition at a volume loading of 43-46%. The origin of this transition was studied using acoustic spectroscopy, zeta potential measurements and oscillatory rheology. The phenomenon occurs due to a volume fraction solids dependent reduction in the zeta potential of the solid phase. It is postulated to result from divalent ion binding within the polyelectrolyte dispersant chain, and was mitigated using a polyethylene glycol plasticizing additive. Chemically prepared zinc oxide powders were processed for the production of high aspect ratio varistor components. Near net shape casting methods including slip casting and agarose gelcasting were evaluated for effectiveness in achieving a uniform green microstructure achieving density values near the theoretical maximum during sintering. The structure of the green parts was examined by mercury porisimetry. Agarose gelcasting produced green parts with low solids loading values and did not achieve high fired density. Isopressing the agarose cast parts after drying raised the fired density to greater than 95%, but the parts exhibited catastrophic shorting during electrical testing. Slip casting produced high green density parts, which exhibited high fired density values. The electrical characteristics of slip cast parts are comparable with dry pressed powder compacts. Alternative methods for near net shape forming of ceramic dispersions were investigated for use with the chemically prepared ZnO material. Recommendations for further investigation to achieve a viable production process are presented.

  18. Chemical Structure of Carbon Nitride Films Prepared by MW-ECR Plasma Enhanced Magnetron Sputtering

    Institute of Scientific and Technical Information of China (English)

    XU Jun; GAO Peng; DING Wan-yu; LI Xin; DENG Xin-lu; DONG Chuang

    2004-01-01

    Amorphous carbon nitride thin films were prepared by plasma-enhanced DC magnetron sputtering using twinned microwave electron cyclotron resonance plasma sources. Chemical structure of deposited films was investigated using X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The results indicate that the deposition rate is strongly affected by direct current bias, and the films are mainly composed of a single amorphous carbon nitride phase with N/C ratio close to C3N4, and the bonding is predominantly of C-N type.

  19. Chemical Structure of Carbon Nitride Films Prepared by MW-ECR Plasma Enhanced Magnetron Sputtering

    Institute of Scientific and Technical Information of China (English)

    XUJun,GAOPeng; DINGWan-yu; LIXin; DENGXin-lu; DONGChuang

    2004-01-01

    Amorphous carbon nitride thin films were prepared by plasma-enhanced DC magnetron sputtering using twinned microwave electron cyclotron resonance plasma sources. Chemical structure of deposited films was investigated using X-ray photoelectron spectroscopy and Fourier transtorm infrared spectroscopy. The results indicate that the deposition rate is strongly affected by direct current bias, and the films are mainly composed of a single amorphous carbon nitride phase with N/C ratio close to C3N4, and the bonding is predominantly of C-N type.

  20. Characterization and Functional Applications of Nanoporous Ag Foams Prepared by Chemical Dealloying

    Science.gov (United States)

    Wu, T. Y.; Wang, X.; Huang, J. C.; Tsai, W. Y.; Chu, Y. Y.; Chen, S. Y.; Du, X. H.

    2015-10-01

    In this study, the pure Ag nanoporous foams, with open cell pore volume fractions 55 to 70 pct and pore sizes 100 to 400 nm, have been prepared by chemical dealloying. The Ag nanoporous foams possess favorable modulus (~0.7 GPa) and strength (~14 MPa), much higher than most of the polymers or ceramic foams. It is found that the Ag nanoporous foams are appropriate candidates for the catalytic and electrode applications. However, they do not exhibit efficient anti-bacterial effect, unless much smaller bacteria with cell sizes of 100 nm or less in the neighborhood are encountered.

  1. FragIt: A Tool to Prepare Input Files for Fragment Based Quantum Chemical Calculations

    CERN Document Server

    Steinmann, Casper; Hansen, Anne S; Jensen, Jan H

    2012-01-01

    Near linear scaling fragment based quantum chemical calculations are becoming increasingly popular for treating large systems with high accuracy and is an active field of research. However, it remains difficult to set up these calculations without expert knowledge. To facilitate the use of such methods, software tools need to be available for support, setup and lower the barrier of entry for usage by non-experts. We present a fragmentation methodology and accompanying tools called FragIt to help setup these calculations. It uses the SMARTS language to find chemically appropriate substructures in structures and is used to prepare input files for the fragment molecular orbital method in the GAMESS program package. We present patterns of fragmentation for proteins and polysaccharides, specifically D-galactopyranose for use in cyclodextrins.

  2. Preparation of tetragonal CaO-ZrO2 nano-powder by chemical coprecipitation method

    Institute of Scientific and Technical Information of China (English)

    刘建本; 阮建明; 邹俭鹏; 李亚军; 骆锋

    2003-01-01

    With zirconium oxychloride, nitrate of lime and ammonia as raw materials, nano-powder of CaO-ZrO2 was prepared by chemical coprecipitation method. By use of azeotropic distillation processing, chemical coprecipitation precursor was obtained. Phase transformation of the precursor was observed at the temperature of 593.81 ℃ and 1 234.56 ℃ respectively with DTA analyses. Phase structure was analyzed through XRD and Raman spectra. The average particle size of tetragonal zirconium oxide powder was 9.8 and 43.7 nm after calcination at 600 and 1 100 ℃ respectively which was tested by TEM and BET analyses. Furthermore, the influences of the doping of nitrate of lime and the average particle size of zirconium oxide on the stability of tetragonal zirconium oxide were also discussed.

  3. Electrical properties of chemically prepared nonstoichiometric CuIn(S,Se)2 thin films

    Indian Academy of Sciences (India)

    R H Bari; L A Patil; A Soni; G S Okram

    2007-04-01

    Polycrystalline thin films of copper indium sulphoselenide [CuIn(S,Se)2] were deposited on glass substrate by chemical bath deposition technique. The deposition parameters such as pH, temperature and time were optimized. A set of films having different elemental compositions was prepared by varying Cu/In ratio from 1.87–12.15. The films were characterized by X-ray diffraction (XRD) and energy dispersive X-ray analysis (EDAX). The chemical composition of the CuIn(S,Se)2 was found to be nonstoichiometric. The d.c. conductivities of the films were studied below and near room temperature. The thermo-electric power of the films was also measured and type of semiconductivity was ascertained.

  4. High quality thin films of thermoelectric misfit cobalt oxides prepared by a chemical solution method.

    Science.gov (United States)

    Rivas-Murias, Beatriz; Manuel Vila-Fungueiriño, José; Rivadulla, Francisco

    2015-07-08

    Misfit cobaltates ([Bi/Ba/Sr/Ca/CoO]n(RS)[CoO2]q) constitute the most promising family of thermoelectric oxides for high temperature energy harvesting. However, their complex structure and chemical composition makes extremely challenging their deposition by high-vacuum physical techniques. Therefore, many of them have not been prepared as thin films until now. Here we report the synthesis of high-quality epitaxial thin films of the most representative members of this family of compounds by a water-based chemical solution deposition method. The films show an exceptional crystalline quality, with an electrical conductivity and thermopower comparable to single crystals. These properties are linked to the epitaxial matching of the rock-salt layers of the structure to the substrate, producing clean interfaces free of amorphous phases. This is an important step forward for the integration of these materials with complementary n-type thermoelectric oxides in multilayer nanostructures.

  5. High quality thin films of thermoelectric misfit cobalt oxides prepared by a chemical solution method

    Science.gov (United States)

    Rivas-Murias, Beatriz; Manuel Vila-Fungueiriño, José; Rivadulla, Francisco

    2015-01-01

    Misfit cobaltates ([Bi/Ba/Sr/Ca/CoO]nRS[CoO2]q) constitute the most promising family of thermoelectric oxides for high temperature energy harvesting. However, their complex structure and chemical composition makes extremely challenging their deposition by high-vacuum physical techniques. Therefore, many of them have not been prepared as thin films until now. Here we report the synthesis of high-quality epitaxial thin films of the most representative members of this family of compounds by a water-based chemical solution deposition method. The films show an exceptional crystalline quality, with an electrical conductivity and thermopower comparable to single crystals. These properties are linked to the epitaxial matching of the rock-salt layers of the structure to the substrate, producing clean interfaces free of amorphous phases. This is an important step forward for the integration of these materials with complementary n-type thermoelectric oxides in multilayer nanostructures. PMID:26153533

  6. A CHEMICAL PROCESS FOR PREPARING CELLULOSIC FIBERS HIERARCHICALLY FROM KENAF BAST FIBERS

    Directory of Open Access Journals (Sweden)

    Jinshu Shi

    2011-02-01

    Full Text Available The objective of this research was to evaluate an all-chemical process to prepare nano-scale to macro-scale cellulosic fibers from kenaf bast fibers, for polymer composite reinforcement. The procedure used in this all-chemical process included alkaline retting to obtain single cellulosic retted fiber, bleaching treatment to obtain delignified bleached fiber, and acidic hydrolysis to obtain both pure-cellulose microfiber and cellulose nanowhisker (CNW. At each step of this chemical process, the resultant fibers were characterized for crystallinity using X-ray diffraction (XRD, for functional groups using the Fourier Transform Infrared spectroscopy (FTIR, and for surface morphology using both the scanning electron microscopy (SEM and transmission electron microscopy (TEM. The chemical components of the different scale fibers were analyzed. Based on the raw kenaf bast fibers, the yields of retted fibers and bleached fibers were 44.6% and 41.4%. The yield of the pure cellulose microfibers was 26.3%. The yield of CNWs was 10.4%, where about 22.6% α-cellulose had been converted into CNWs. The fiber crystallinity increased as the scale of the fiber decreased, from 49.9% (retted single fibers to 83.9% (CNWs. The CNWs had fiber lengths of 100 nm to 1400 nm, diameters of 7 to 84 nm, and aspect ratios of 10 to 50. The incorporation of 9% (wt% CNWs in polyvinyl alcohol (PVA composites increased the tensile strength by 46%.

  7. CdS thin films prepared by laser assisted chemical bath deposition

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, L.V.; Mendivil, M.I.; Garcia Guillen, G.; Aguilar Martinez, J.A. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, Av. Pedro de Alba s/n, Ciudad Universitaria, San Nicolas de los Garza, Nuevo Leon 66450 (Mexico); Krishnan, B. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, Av. Pedro de Alba s/n, Ciudad Universitaria, San Nicolas de los Garza, Nuevo Leon 66450 (Mexico); CIIDIT – Universidad Autonoma de Nuevo Leon, Apodaca, Nuevo Leon (Mexico); Avellaneda, D.; Castillo, G.A.; Das Roy, T.K. [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, Av. Pedro de Alba s/n, Ciudad Universitaria, San Nicolas de los Garza, Nuevo Leon 66450 (Mexico); Shaji, S., E-mail: sshajis@yahoo.com [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, Av. Pedro de Alba s/n, Ciudad Universitaria, San Nicolas de los Garza, Nuevo Leon 66450 (Mexico); CIIDIT – Universidad Autonoma de Nuevo Leon, Apodaca, Nuevo Leon (Mexico)

    2015-05-01

    Highlights: • CdS thin films by conventional CBD and laser assisted CBD. • Characterized these films using XRD, XPS, AFM, optical and electrical measurements. • Accelerated growth was observed in the laser assisted CBD process. • Improved dark conductivity and good photocurrent response for the LACBD CdS. - Abstract: In this work, we report the preparation and characterization of CdS thin films by laser assisted chemical bath deposition (LACBD). CdS thin films were prepared from a chemical bath containing cadmium chloride, triethanolamine, ammonium hydroxide and thiourea under various deposition conditions. The thin films were deposited by in situ irradiation of the bath using a continuous laser of wavelength 532 nm, varying the power density. The thin films obtained during deposition of 10, 20 and 30 min were analyzed. The changes in morphology, structure, composition, optical and electrical properties of the CdS thin films due to in situ irradiation of the bath were analyzed by atomic force microscopy (AFM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV–vis spectroscopy. The thin films obtained by LACBD were nanocrystalline, photoconductive and presented interesting morphologies. The results showed that LACBD is an effective synthesis technique to obtain nanocrystalline CdS thin films having good optoelectronic properties.

  8. CdS thin films prepared by laser assisted chemical bath deposition

    International Nuclear Information System (INIS)

    Highlights: • CdS thin films by conventional CBD and laser assisted CBD. • Characterized these films using XRD, XPS, AFM, optical and electrical measurements. • Accelerated growth was observed in the laser assisted CBD process. • Improved dark conductivity and good photocurrent response for the LACBD CdS. - Abstract: In this work, we report the preparation and characterization of CdS thin films by laser assisted chemical bath deposition (LACBD). CdS thin films were prepared from a chemical bath containing cadmium chloride, triethanolamine, ammonium hydroxide and thiourea under various deposition conditions. The thin films were deposited by in situ irradiation of the bath using a continuous laser of wavelength 532 nm, varying the power density. The thin films obtained during deposition of 10, 20 and 30 min were analyzed. The changes in morphology, structure, composition, optical and electrical properties of the CdS thin films due to in situ irradiation of the bath were analyzed by atomic force microscopy (AFM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV–vis spectroscopy. The thin films obtained by LACBD were nanocrystalline, photoconductive and presented interesting morphologies. The results showed that LACBD is an effective synthesis technique to obtain nanocrystalline CdS thin films having good optoelectronic properties

  9. Physical and Chemical Transformation of Hydroxyapatite Nanoparticles in Aqueous Sol after Preparation and in vitro

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The co-precipitation method followed by ultrasound and heat treatment is a common way to prepare below 100 nm sized hydroxyapatite nanoparticles for biomedical studies and applications. The size and pH value of the obtained calcium phosphate nanoparticles in aqueous sol have a strong impact on the interactions with cells and tissue. The physical and chemical properties of material samples for in vitro and in vivo studies are often assumed to remain constant from the time after fabrication to the actual use. Only little attention is paid to eventual changes of the material over time or due to the different in vitro conditions. In this study, the physical and chemical transformation of calcium phosphate nanoparticles after preparation and in vitro was investigated. As the result showed, dispersed nano sized amorphous calcium phosphate precipitation as well as crystallized hydroxyapatite nanoparticles continue to crystallize even when kept at 4 ℃ leading to declining pH values and particle sizes.Due to the pH buffer in the medium the pH value of the cell culture remained stable after adding 20% nanoparticle sol in vitro. However, hydroxyapatite nanoparticles immediately became unstable in the presents of cell culture medium. The resulting loose agglomerations showed a size of above 500 nm.

  10. Preparation of Superhydrophobic ZnO Films on Zinc Substrate by Chemical Solution Method

    Institute of Scientific and Technical Information of China (English)

    XU Wen-guo; LI Ji-hong; LU Shi-xiang; DUAN Ya-qiong; MA Cheng-xiang; SHI Xiao-feng; CHEN Yi-ling; YANG Yan-bo

    2012-01-01

    Superhydrophobic surface was prepared on the zinc substrate by chemical solution method via immersing clean pure zinc substrate into a water solution of zinc nitrate hexahydrate[Zn(NO3)2.6H2O] and hexamethylenetetraamine(C6H12N4) at 95℃ in water bath for 1.5 h,then modified with 18 alkanethiol.The best resulting surface shows superhydrophobic properties with a water contact angle of about 158° and a low water roll-off angle of around 3°.The prepared samples were characterize.d by powder X-ray diffraction(XRD),X-ray photoelectron spectroscopy (XPS),energy-dispersive X-ray spectroscopy(EDX),transmission electron microscopy(TEM),and scanning electron microscopy(SEM).SEM images of the films show that the resulting surface exhibits flower-shaped micro- and nano-structure.The surfaces of the prepared films were composed of ZnO nanorods which were wurtzite structure.The special flower-like micro- and nano-structure along with the low surface energy leads to the surface superhydrophobicity.

  11. [Isolation of chemical constituents from Ziziphora clinopodioides Lam. with recycling preparative high performance liquid chromatography].

    Science.gov (United States)

    Li, Guozhu; Meng, Qingyan; Luo, Bi; Ge, Zhenghong; Liu, Wenjie

    2015-01-01

    The combination of alternate recycling and direct recycling preparative liquid chromatography method was developed for the isolation of chemical constituents from Ziziphora clinopodioides Lam. The crude extract was obtained from Ziziphora clinopodioides Lam. by solvent extraction, column chromatography and reversed-phase (RP) flash chromatography. All the separations were performed with methanol and water as mobile phases and the developed recycling preparative method was used with twin RP columns switched by a two-position ten-way valve for the separation. The mobile phase was recycled in close loop with a two-position six-way valve. The fraction I and fraction II from reversed-phase flash chromatography were selected for the demonstration of separation power of the proposed protocol, and five compounds were obtained from Ziziphora clinopodioides Lam. The isolated five compounds were identified as pinocembrin-7-O-rutinoside, pinocembrin-7-O-rutinoside, acacetin-7-O-rutinoside, picein and protocatechuic acid with nuclear magnetic resonance (NMR). The experimental results showed that the developed preparation method exhibited higher separation efficiency with less mobile phase used than the reported methods, and could be expected as an effective method for the separation of complex natural products, especially the compounds with similar structures. PMID:25958674

  12. High quality antireflective ZnS thin films prepared by chemical bath deposition

    Energy Technology Data Exchange (ETDEWEB)

    Tec-Yam, S.; Rojas, J.; Rejon, V. [Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Merida, Departamento de Fisica Aplicada, Km. 6 Antigua Carretera a Progreso, AP 73-Cordemex, 97310 Merida Yucatan (Mexico); Oliva, A.I., E-mail: oliva@mda.cinvestav.mx [Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Merida, Departamento de Fisica Aplicada, Km. 6 Antigua Carretera a Progreso, AP 73-Cordemex, 97310 Merida Yucatan (Mexico)

    2012-10-15

    Zinc sulfide (ZnS) thin films for antireflective applications were deposited on glass substrates by chemical bath deposition (CBD). Chemical analysis of the soluble species permits to predict the optimal pH conditions to obtain high quality ZnS films. For the CBD, the ZnCl{sub 2}, NH{sub 4}NO{sub 3}, and CS(NH{sub 2}){sub 2} were fixed components, whereas the KOH concentration was varied from 0.8 to 1.4 M. Groups of samples with deposition times from 60 to 120 min were prepared in a bath with magnetic agitation and heated at 90 Degree-Sign C. ZnS films obtained from optimal KOH concentrations of 0.9 M and 1.0 M exhibited high transparency, homogeneity, adherence, and crystalline. The ZnS films presented a band gap energy of 3.84 eV, an atomic Zn:S stoichiometry ratio of 49:51, a transmittance above 85% in the 300-800 nm wavelength range, and a reflectance below 25% in the UV-Vis range. X-ray diffraction analysis revealed a cubic structure in the (111) orientation for the films. The thickness of the films was tuned between 60 nm and 135 nm by controlling the deposition time and KOH concentration. The incorporation of the CBD-ZnS films into ITO/ZnS/CdS/CdTe and glass/Mo/ZnS heterostructures as antireflective layer confirms their high optical quality. -- Highlights: Black-Right-Pointing-Pointer High quality ZnS thin films were prepared by chemical bath deposition (CBD). Black-Right-Pointing-Pointer Better CBD-ZnS films were achieved by using 0.9 M-KOH concentration. Black-Right-Pointing-Pointer Reduction in the reflectance was obtained for ZnS films used as buffer layers.

  13. Effect of Organic Solvents in Preparation of Silica-Based Chemical Gel Decontaminates for Decontamination of Nuclear Facilities

    International Nuclear Information System (INIS)

    Decontamination of nuclear facilities is necessary to reduce the radiation field during normal operations and decommissioning of complex equipment such as stainless steel components, other iron-based steel and alloys, metal surfaces, structural materials and so on. Chemical decontamination technology in particular is a highly effective method to remove the radioactive contamination through a chemical dissolution or a redox reaction. However, this method has the serious drawback due to the generation of large amounts of the radioactive liquid wastes. Recently, a few literatures have been reported for the preparation of the chemical gel decontaminants to reduce the amount of the radioactive liquid wastes and to enhance the decontamination efficiency through increasing the contact time between the gels and the radioactive contaminants. In the preparation of the chemical gels, the control of the viscosity highly depends on the amount of a coviscosifier used among the components of the chemical gels consisted of a viscosifier, a coviscosifier, and a chemical decontaminant. In this works, a new effective method for the preparation of the chemical gel was investigated by introducing the organic solvents. The mixture solution of the coviscosifier and organic solvent was more effective in the control of the viscosity compared with that of the coviscosifier only in gels. Furthermore, the decontamination efficiency of the chemical gels measured by using the multi-channel analyzer (MCA) showed the high decontamination factor for Co-60 and Cs-137 contaminated on the surface of the stainless steel 304

  14. Preparation of diamond/Cu microchannel heat sink by chemical vapor deposition

    Institute of Scientific and Technical Information of China (English)

    刘学璋; 罗浩; 苏栩; 余志明

    2015-01-01

    A Ti interlayer with thickness about 300 nm was sputtered on Cu microchannels, followed by an ultrasonic seeding with nanodiamond powders. Adherent diamond film with crystalline grains close to thermal equilibrium shape was tightly deposited by hot-filament chemical vapor deposition (HF-CVD). The nucleation and growth of diamond were investigated with micro-Raman spectroscope and field emission scanning electron microscope (FE-SEM) with energy dispersive X-ray detector (EDX). Results show that the nucleation density is found to be up to 1010 cm−2. The enhancement of the nucleation kinetics can be attributed to the nanometer rough Ti interlayer surface. An improved absorption of nanodiamond particles is found, which act as starting points for the diamond nucleation during HF-CVD process. Furthermore, finite element simulation was conducted to understand the thermal management properties of prepared diamond/Cu microchannel heat sink.

  15. MICROSTRUCTURE OF SiOx:H FILMS PREPARED BY PLASMA ENHANCED CHEMICAL VAPOR DEPOSITION

    Institute of Scientific and Technical Information of China (English)

    MA ZHI-XUN; LIAO XIAN-BO; KONG GUANG-LIN; CHU JUN-HAO

    2000-01-01

    The micro-Raman spectroscopy and infrared (IR) spectroscopy have been performed for the study of the microstructure of amorphous hydrogenated oxidized silicon (a-SiOx:H) films prepared by Plasma Enhanced Chemical Vapor Deposition technique. It is found that a-SiOx :H consists of two phases: an amorphous silicon-rich phase and an oxygen-rich phase mainly comprised of HSi-SiO2 and HSi-O3. The Raman scattering results exhibit that the frequency of TO-like mode of amorphous silicon red-shifts with decreasing size of silicon-rich region. This is related to the quantum confinement effects, similar to the nanocrystalline silicon.

  16. Characterization of doped hydrogenated nanocrystalline silicon films prepared by plasma enhanced chemical vapour deposition

    Institute of Scientific and Technical Information of China (English)

    Wang Jin-Liang; Wu Er-Xing

    2007-01-01

    The B-and P-doped hydrogenated nanocrystalline silicon films (nc-Si:H) are prepared by plasma-enhanced chemical vapour deposition (PECVD) .The microstructures of doped nc-Si:H films are carefully and systematically char acterized by using high resolution electron microscopy (HREM) ,Raman scattering,x-ray diffraction (XRD) ,Auger electron spectroscopy (AES) ,and resonant nucleus reaction (RNR) .The results show that as the doping concentration of PH3 increases,the average grain size (d) tends to decrease and the crystalline volume percentage (Xc) increases simultaneously.For the B-doped samples,as the doping concentration of B2H6 increases,no obvious change in the value of d is observed,but the value of Xc is found to decrease.This is especially apparent in the case of heavy B2H6 doped samples,where the films change from nanocrystalline to amorphous.

  17. Characterization and Wettability of ZnO Film Prepared by Chemical Etching Method

    Institute of Scientific and Technical Information of China (English)

    GUO Hua-xi; JIA Hui-ying; ZENG Jian-bo; CONG Qian; REN Lu-quan

    2013-01-01

    ZnO thin films were prepared by a chemical etching method and their wettability was investigated.The structure and surface composition structure were characterized by means of scanning electron microscopy,X-ray photoelectronic spectrometry(XPS),X-ray diffraction(XRD) and Raman spectrometry.These analyses reveal that the etched films were large-scale micro-nanohierarchical structures composed of a Zn core and a ZnO coating.Superhydrophobic surfaces with water contact angles of over 150° were obtained by n-octadecanethiol(ODT) modification.The XPS and Raman results indicate that ODT molecules were bound to the ZnO surface with the S head group by forming Zn—S bond.

  18. A novel colloid probe preparation method based on chemical etching technique

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Several fundamental problems in hydrophobic force measurements using atomic force microscope (AFM) are discussed in this paper. A novel method for colloid probe preparation based on chemical etching technology is proposed, which is specially fit for the unique demands of hydrophobic force measurements by AFM. The features of three different approaches for determining spring constants of rectangular cantilevers, including geometric dimension, Cleveland and Sader methods are compared. The influences of the sizes of the colloids on the measurements of the hydrophobic force curves are investigated. Our experimental results showed that by selecting colloid probe with proper spring constant and tip size, the hydrophobic force and the complete hydrophobic interaction force curve can be measured by using AFM.

  19. Highly sensitive methanol chemical sensor based on undoped silver oxide nanoparticles prepared by a solution method

    International Nuclear Information System (INIS)

    We have prepared silver oxide nanoparticles (NPs) by a simple solution method using reducing agents in alkaline medium. The resulting NPs were characterized by UV-vis and FT-IR spectroscopy, X-ray powder diffraction, and field-emission scanning electron microscopy. They were deposited on a glassy carbon electrode to give a sensor with a fast response towards methanol in liquid phase. The sensor also displays good sensitivity and long-term stability, and enhanced electrochemical response. The calibration plot is linear (r2 = 0.8294) over the 0.12 mM to 0.12 M methanol concentration range. The sensitivity is ∼ 2.65 μAcm-2 mM-1, and the detection limit is 36.0 μM (at a SNR of 3). We also discuss possible future prospective uses of this metal oxide semiconductor nanomaterial in terms of chemical sensing. (author)

  20. Femtosecond Transient Absorption Studies in Cadmium Selenide Nanocrystal Thin Films Prepared by Chemical Bath Deposition Method

    Directory of Open Access Journals (Sweden)

    M. C. Rath

    2007-01-01

    Full Text Available Dynamics of photo-excited carrier relaxation processes in cadmium selenide nanocrystal thin films prepared by chemical bath deposition method have been studied by nondegenerate femtosecond transient pump-probe spectroscopy. The carriers were generated by exciting at 400 nm laser light and monitored by several other wavelengths. The induced absorption followed by a fast bleach recovery observed near and above the bandgap indicates that the photo-excited carriers (electrons are first trapped by the available traps and then the trapped electrons absorb the probe light to show a delayed absorption process. The transient decay kinetics was found to be multiexponential in nature. The short time constant, <1 picosecond, was attributed to the trapping of electrons by the surface and/or deep traps and the long time constant, ≥20 picoseconds, was due to the recombination of the trapped carriers. A very little difference in the relaxation processes was observed in the samples prepared at bath temperatures from 25∘C to 60∘C.

  1. Octafluorodirhenate(III) Revisited: Solid-State Preparation, Characterization, and Multiconfigurational Quantum Chemical Calculations.

    Science.gov (United States)

    Mariappan Balasekaran, Samundeeswari; Todorova, Tanya K; Pham, Chien Thang; Hartmann, Thomas; Abram, Ulrich; Sattelberger, Alfred P; Poineau, Frederic

    2016-06-01

    A simple method for the high-yield preparation of (NH4)2[Re2F8]·2H2O has been developed that involves the reaction of (n-Bu4N)2[Re2Cl8] with molten ammonium bifluoride (NH4HF2). Using this method, the new salt [NH4]2[Re2F8]·2H2O was prepared in ∼90% yield. The product was characterized in solution by ultraviolet-visible light (UV-vis) and (19)F nuclear magnetic resonance ((19)F NMR) spectroscopies and in the solid-state by elemental analysis, powder X-ray diffraction (XRD), and infrared (IR) spectroscopy. Multiconfigurational CASSCF/CASPT2 quantum chemical calculations were performed to investigate the molecular and electronic structure, as well as the electronic absorption spectrum of the [Re2F8](2-) anion. The metal-metal bonding in the Re2(6+) unit was quantified in terms of effective bond order (EBO) and compared to that of its [Re2Cl8](2-) and [Re2Br8](2-) analogues.

  2. Morphology of CdSe films prepared by chemical bath deposition: The role of substrate

    Energy Technology Data Exchange (ETDEWEB)

    Simurda, M. [Charles University in Prague, Faculty of Mathematics and Physics, Ke Karlovu 3, 121 16 Prague 2 (Czech Republic); Nemec, P. [Charles University in Prague, Faculty of Mathematics and Physics, Ke Karlovu 3, 121 16 Prague 2 (Czech Republic)]. E-mail: nemec@karlov.mff.cuni.cz; Formanek, P. [Institut fuer Strukturphysik, Technische Universitaet Dresden, Zellescher Weg 16, D-01062 Dresden (Germany); Nemec, I. [Charles University in Prague, Faculty of Science, Albertov 6, 128 43 Prague 2 (Czech Republic); Nemcova, Y. [Charles University in Prague, Faculty of Science, Albertov 6, 128 43 Prague 2 (Czech Republic); Maly, P. [Charles University in Prague, Faculty of Mathematics and Physics, Ke Karlovu 3, 121 16 Prague 2 (Czech Republic)

    2006-07-26

    We combine optical spectroscopy and transmission electron microscopy to study the growth and the structural morphology of CdSe films prepared by chemical bath deposition (CBD) on two considerably different substrates. The films grown on glass are compact and strongly adherent to the substrate. On the contrary, the films deposited on carbon-coated glass (with approx. 20 nm thick amorphous carbon layer) are only loosely adherent to the substrate. Using transmission electron microscopy we revealed that even though the films grown on both substrates are assembled from closely spaced nanocrystals with diameter of about 5 nm, the films morphology on the sub-micrometer scale is considerably different in the two cases. While the films deposited on glass are rather compact, the films prepared on carbon layer have high porosity and are formed by interconnected spheres which size is dependent on the duration of deposition (e.g. 155 nm for 6 h and 350 nm for 24 h). This shows that the choice of the substrate for CBD has a stronger influence on the sub-micrometer film morphology than on the properties of individual nanocrystals forming the film.

  3. Morphology of CdSe films prepared by chemical bath deposition: The role of substrate

    International Nuclear Information System (INIS)

    We combine optical spectroscopy and transmission electron microscopy to study the growth and the structural morphology of CdSe films prepared by chemical bath deposition (CBD) on two considerably different substrates. The films grown on glass are compact and strongly adherent to the substrate. On the contrary, the films deposited on carbon-coated glass (with approx. 20 nm thick amorphous carbon layer) are only loosely adherent to the substrate. Using transmission electron microscopy we revealed that even though the films grown on both substrates are assembled from closely spaced nanocrystals with diameter of about 5 nm, the films morphology on the sub-micrometer scale is considerably different in the two cases. While the films deposited on glass are rather compact, the films prepared on carbon layer have high porosity and are formed by interconnected spheres which size is dependent on the duration of deposition (e.g. 155 nm for 6 h and 350 nm for 24 h). This shows that the choice of the substrate for CBD has a stronger influence on the sub-micrometer film morphology than on the properties of individual nanocrystals forming the film

  4. YBCO coated conductors prepared by chemical solution deposition: A TEM study

    International Nuclear Information System (INIS)

    Recently large attention has been devoted to chemical solution deposition (CSD) as a promising method for fabricating low-cost YBCO coated conductors. We present an extensive transmission electron microscopy (TEM) cross-section analysis of CSD grown La2Zr2O7 (LZO) buffer layers on flexible Ni-5at%W substrates. The high performance of these chemical solution derived buffer layers was confirmed by a YBCO critical current density Jc of 0.84 MA/cm2 achieved for a coated conductor sample with a layer sequence Ni-5at%W/LZO (CSD)/CeO2 (CSD)/YBCO, where the YBCO film was deposited by pulsed laser deposition (PLD). TEM sample preparation was carried out by conventional mechanical polishing and ion milling techniques. TEM bright-field images of the LZO films and nickel substrates were acquired under two-beam conditions. The layer thicknesses and nanovoid size were determined for the LZO buffer layers. Moreover, the interfaces between the different layers were investigated and identified. Electron diffraction patterns were obtained in order to determine the microscopic texture of the samples. Despite the presence of nanovoids in the LZO buffer layers, they act as efficient Ni diffusion barriers

  5. Preparation of High Impermeable and Crack-resistance Chemical Admixture and Its Mechanism

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    A kind of high impermeable and crack-resistance chemical admixture (HICRCA) was prepared, which is a compound chemical admixture composed of an expansion ingredient,density ingredient, and organic hydrophobic poreblocking ingredient. The results of the experiments indicate that the addition of HICRCA improves mortar and concrete in the following performances:(1) perfect workability: slump is more than 22cm, the slump after 3h is about 16cm; (2)high impermeability:for the mortar,the pervious height under a water pressure of 1.5MPa is 1.5cm,for the concrete, the pervious height under a water pressure of 5.0MPa is 2.2cm;(3)high crack-resistance:there is a micro-expansion at the age of 90d;(4)high compressivestrength:compared with the controlled concrete,the compressive strengths at the age of 3d and 28d are improved by 66.4% and 62.0%, respectively.At the same time,the effects of different curing condition on mortar and concrete expansive and shrinkage performance were studied.In addition,the impermeable and crack-resistance mechanism was investigated in the present paper.

  6. Chemical and biological assessment of Angelica herbal decoction: comparison of different preparations during historical applications.

    Science.gov (United States)

    Zhang, Wendy Li; Zheng, Ken Yu-Zhong; Zhu, Kevin Yue; Zhan, Janis Ya-Xian; Bi, Cathy Wen-Chuan; Chen, Jian-Ping; Du, Crystal Ying-Qing; Zhao, Kui-Jun; Lau, David Tai-Wai; Dong, Tina Ting-Xia; Tsim, Karl Wah-Keung

    2012-08-15

    The commonly used Angelica herbal decoction today is Danggui Buxue Tang (DBT), which is a dietary supplement in treating menopausal irregularity in women, i.e. to nourish "Qi" and to enrich "Blood". According to historical record, many herbal decoctions were also named DBT, but the most popular formulation of DBT was written in Jin dynasty (1247 AD) of China, which contained Astragali Radix (AR) and Angelicae Sinensis Radix (ASR) with a weight ratio of 5:1. However, at least two other Angelica herbal decoctions recorded as DBT were prescribed in Song (1155 AD) and Qing dynasties (1687 AD). Although AR and ASR are still the major components in the DBT herbal decoctions, they are slightly varied in the herb composition. In order to reveal the efficiency of different Angelica herbal decoctions, the chemical and biological properties of three DBT herbal extracts were compared. Significantly, the highest amounts of AR-derived astragaloside III, astragaloside IV, calycosin and formononetin and ASR-derived ferulic acid were found in DBT described in 1247 AD: this preparation showed stronger activities in osteogenic, estrogenic and erythropoetic effects than the other two DBT. The current results supported the difference of three DBT in chemical and biological properties, which could be a result of different herbal combinations. For the first time, this study supports the popularity of DBT described in 1247 AD. PMID:22902230

  7. Preparation and Determination of the Physical and Chemical Properties of Margarine

    Directory of Open Access Journals (Sweden)

    Habazin, S.

    2012-02-01

    Full Text Available Nutrition is one of the most basic needs of the human body. It ensures the introduction of substances needed to sustain life of the organism, its growth and proper development. In the food pyramid, fats together with carbohydrates are at the very top. One source of fat in human nutrition is margarine. Margarine comprises at least 82 % vegetable fats and 16 % water. The remainder consists of lecithin, sugar, salt, colours, and vitamins.The margarine production process involves hydrogenation of vegetable fats, assembling the margarine mixture, emulsifying, crystallization and packing.The objective of this study was to show that margarine could be prepared in a school laboratory under conditions that are applicable for such laboratory. Meaning:a In a school laboratory at normal pressure and at elevated temperature with nickel as catalyst, i.e. without the use of an autoclave, carry out the reaction of hydrogenation soybean and palm oil in order to obtain a vegetable fat that is the basic ingredient of margarine. During the preparation of margarine, the hydrogenation reaction was carefully monitored by determining the iodine value.b Preparation of margarine obtained from vegetable fats.c Determination and comparison of selected physical and chemical properties of the product with the same properties of several types of margarines available on the market. The following properties were determined:– Melting point, in order to obtain composition of fat phase and determine suitability for humanuse.– Acid value, as an indicator of the amount of free fatty acids that influence the taste.– Peroxide value, for insight into the oxidative stability of fats.This work has shown that it is possible to make vegetable fat in a school lab by hydrogenation of vegetable oils. Unlike the industrial process of hydrogenation carried out under a pressure of 0.36 to 2 atm, which takes about two hours, our reaction was carried out at atmospheric pressure but with a

  8. Identification of chemicals relevant to the Chemical Weapons Convention using the novel sample-preparation methods and strategies of the Mobile Laboratory of the Organization for the Prohibition of Chemical Weapons

    NARCIS (Netherlands)

    O. Terzic; H. Gregg; P. de Voogt

    2014-01-01

    The standard approach to on-site sample preparation for gas chromatography-mass spectrometry analysis of chemicals relevant to the Chemical Weapons Convention provides relatively good coverage of the target analytes, but it suffers from a number of drawbacks, such as low sample throughput, use of bu

  9. Physical chemical and citotoxic evaluation of highly diluted solutions of Euphorbia tirucalli L. prepared through the fifty milesimal homeopathic method

    Directory of Open Access Journals (Sweden)

    Carlos Renato Zacharias

    2010-07-01

    Full Text Available Background: although Hahnemann described the fifty-milesimal (LM method in the 6th edition of the Organon of the Medical Art, very little research has been carried out on the physical chemical properties of these homeopathic preparations. Furthermore, there is still no evidence allowing for the correlation between the alleged physical chemical properties and the biological effects of high dilutions. Aims: to evaluate physical chemical characteristics of LM preparations including electrical conductivity, pH and refraction index, and their effect on biological experimental models. Materials and methods: preparations tested for physical chemical analysis were dilutions 1 lm to 10 lm of Euphorbia tirucalli L. prepared from the latex and the juice of the plant. To rule the seasonal characteristics of this plant, 2 different populations were used, one collected in June 2007 and the other in May 2008. Furthermore, the cytotoxic effect of Euphorbia tirucalli 5 lm was tested on human breast cancer cells (MCF7 through MTT assay. Some differences among the two collections were observed. However, any clear correlation could be observed between physical chemical properties and biological activity.

  10. Octafluorodirhenate(III) Revisited: Solid-State Preparation, Characterization, and Multiconfigurational Quantum Chemical Calculations

    Energy Technology Data Exchange (ETDEWEB)

    Mariappan Balasekaran, Samundeeswari; Todorova, Tanya K.; Pham, Chien Thang; Hartmann, Thomas; Abram, Ulrich; Sattelberger, Alfred P.; Poineau, Frederic

    2016-06-06

    A simple method for the high-yield preparation of (NH4)2[Re2F8]· 2H2O has been developed that involves the reaction of (n-Bu4N)2[Re2Cl8] with molten ammonium bifluoride (NH4HF2). Using this method, the new salt [NH4]2[Re2F8]·2H2O was prepared in ~90% yield. The product was characterized in solution by ultraviolet-visible light (UV-vis) and 19F nuclear magnetic resonance (19F NMR) spectroscopies and in the solid-state by elemental analysis, powder X-ray diffraction (XRD), and infrared (IR) spectroscopy. Multiconfigurational CASSCF/CASPT2 quantum chemical calculations were performed to investigate the molecular and electronic structure, as well as the electronic absorption spectrum of the [Re2F8] 2- anion. The metal-metal bonding in the Re2 6+ unit was quantified in terms of effective bond order (EBO) and compared to that of its [Re2Cl8] 2- and [Re2Br8] 2- analogues.

  11. Optical Characteristics of La-Doped ZnS Thin Films Prepared by Chemical Bath Deposition

    Institute of Scientific and Technical Information of China (English)

    XIE Hai-Qing; CHEN Yuan; HUANG Wei-Qing; HUANG Gui-Fang; PENG Ping; PENG Li; WANG Tai-Hang; ZENG Yun

    2011-01-01

    Undoped and La-doped ZnS thin films are prepared by chemical bath deposition (CBD) process through the co-precipitation reaction of inorganic precursors zinc sulfate, thiosulfate ammonia and La2O3. Composition of the films is analyzed using an energy-dispersive x-ray spectroscopy (EDS). Absorption spectra and spectral transmittances of the films are measured using a double beam UV-VIS spectrophotometer (TU-1901). It is found that significant red shifts in absorption spectra and decrease in absorptivity are obtained with increasing lanthanum. Moreover, optical transmittance is increased as La is doped, with a transmittance of more than 80% for wavelength above 360 nm in La-doped ZnS thin films. Compared to pure ZnS, the band gap decreases and flat-band potential positively shifts to quasi-metal for the La-doped ZnS. These results indicate that La-doped ZnS thin films could be valuably adopted as transparent electrodes.%@@ Undoped and La-doped ZnS thin films are prepared by chemical bath deposition (CBD) process through the co-precipitation reaction of inorganic precursors zinc sulfate, thiosulfate ammonia and La2O2.Composition of the 61ms is analyzed using an energy-dispersive x-ray spectroscopy (EDS).Absorption spectra and spectral tra.nsmitta.nces of the 61ms are measured using a double beam UV-VIS spectrophotometer (TU-1901).It is found that significant red shifts in absorption spectra and decrease in absorptivity are obtained with increasing lanthanum.Moreover, optical transmittance is increased as La is doped, with a transmittance of more than 80% for wavelength above 360 nm in La-doped ZnS thin 61ms.Compared to pure ZnS, the band gap decreases and flat-band potential positively shifts to quasi-metal for the La-doped ZnS.These results indicate that La-doped ZnS thin 6hns could be valuably adopted as transparent electrodes.

  12. The chemical and catalytic properties of nanocrystalline metal oxides prepared through modified sol-gel synthesis

    Science.gov (United States)

    Carnes, Corrie Leigh

    The goal of this research was to synthesize, characterize and study the chemical properties of nanocrystalline metal oxides. Nanocrystalline (NC) ZnO, CuO, NiO, Al2O3, and the binary Al2O 3/MgO and ZnO/CuO were prepared through modified sol gel methods. These NC metal oxides were studied in comparison to the commercial (CM) metal oxides. The samples were characterized by XRD, TGA, FTIR, BET, and TEM. The NC samples were all accompanied by a significant increase in surface area and decrease in crystallite size. Several chemical reactions were studied to compare the NC samples to the CM samples. One of the reactions involved a high temperature reaction between carbon tetrachloride and the oxide to form carbon dioxide and the corresponding metal chloride. A similar high temperature reaction was conducted between the metal oxide and hydrogen sulfide to form water and the corresponding metal sulfide. A room temperature gas phase adsorption was studied where SO2 was adsorbed onto the oxide. A liquid phase adsorption conducted at room temperature was the destructive adsorption of paraoxon (a toxic insecticide). In all reactions the NC samples exhibited greater activity, destroying or adsorbing a larger amount of the toxins compared to the CM samples. To better study surface area effects catalytic reactions were also studied. The catalysis of methanol was studied over the nanocrystalline ZnO, CuO, NiO, and ZnO/CuO samples in comparison to their commercial counterparts. In most cases the NC samples proved to be more active catalysts, having higher percent conversions and turnover numbers. A second catalytic reaction was also studied, this reaction was investigated to look at the support effects. The catalysis of cyclopropane to propane was studied over Pt and Co catalysts. These catalysts were supported onto NC and CM alumina by impregnation. By observing differences in the catalytic behavior, support effects have become apparent.

  13. YBa2Cu3O7-x thin films prepared by chemical solution deposition

    International Nuclear Information System (INIS)

    The discovery of superconductivity in ceramic materials by Bednorz and Mueller in early 1987, immediately followed by Wu et al., who showed that YBa2Cu3O7-x (YBCO) becomes superconducting (92 K) well above the boiling point of nitrogen (77 K) created a great excitement in superconductivity research. Potential applications of high Tc-superconductors require large critical currents and high-applied magnetic fields. Effective ways to increase the critical current density at high magnetic fields in YBCO are the introduction of nanoparticles and chemical substitution of yttrium by other rare earth elements. Since low costs and environmental compatibility are essential conditions for the preparation of long length YBCO films, the cost effective chemical solution deposition (CSD) procedure was selected, given that no vacuum technology is required. To reveal the flexibility and the good optimization possibilities of the CSD approach two main processes were chosen for comparison: a fluorine-free method, namely the polymer-metal precursor technique, and a fluorine-based method, the metalorganic deposition (MOD) using the trifluoroacetates (TFA) technique. Sharp transition temperature widths ΔTc of 1.1 K for the polymer metal method, 0.8 K for TFA method and critical current densities Jc of ∼3.5 MA/cm2 shows that high quality YBCO thin films can be produced using both techniques. Especially interesting is the magnetic field dependence of the critical current density Jc(B) of the Y(Dy)BCO (80 %) films showing that for the lower magnetic fields the critical current density Jc(B) is higher for a standard YBCO film, but at fields higher than 4.5 T the critical current density Jc(B) of Y(Dy)BCO is larger than that for the YBCO. Above 8 T, Jc(B) of the Y(Dy)BCO film is more than one order of magnitude higher than in pure YBCO film. (orig.)

  14. 1,5-Anhydro-D-fructose: biocatalytic and chemical synthetic methods for the preparation, transformation and derivatization

    DEFF Research Database (Denmark)

    Lundt, Inge; Yu, Shukun

    2010-01-01

    1,5-Anhydro-D-fructose (1,5AnFru) is a monoketosaccharide that can be prepared enzymatically from starch by a-1,4-glucan lyase or chemically from D-glucose or D-fructose in a few steps with high yields. The formed 1,5AnFru can be derivatized both enzymatically and chemically to interesting new...... carbohydrate derivatives, some with biological activities. For example dehydratases, isomerases and reductases can convert 1,5AnFru to enolones (as Ascopyrone P) and sugar alcohols with antimicrobial and antioxidant properties, while chemical modifications can give similar compounds as well as natural products...

  15. A Microwave-Based Chemical Factory in the Lab: From Milligram to Multigram Preparations

    Directory of Open Access Journals (Sweden)

    Laura Rinaldi

    2015-01-01

    Full Text Available Microwave technology is changing the way we design and optimize synthetic protocols and their scaling up to multigram production levels. The latest generation of dedicated microwave reactors enables operators to quickly screen reaction conditions by means of parallel tests and select the best catalyst, solvent, and conditions. Pilot scale synthetic procedures require flow-through conditions in microwave flow reactors which can be obtained by adapting classic batch protocols. Microwave-assisted chemical processes play a pivotal role in the design of sustainable multigram preparations which address the double requirement of process intensification and competitive production costs. Although most researchers are likely to be acquainted with the great potential of dielectric heating, the advantages and disadvantages of a particular device or the conditions needed to maximize efficiency and functionality are often overlooked. The double aims of the present review are to provide a panoramic snapshot of commercially available lab microwave reactors and their features as well as highlighting a few selected applications of microwave chemistry of particular relevance.

  16. Electrochromic properties of porous NiO thin films prepared by a chemical bath deposition

    Energy Technology Data Exchange (ETDEWEB)

    Xia, X.H.; Tu, J.P.; Zhang, J.; Wang, X.L. [Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Zhang, W.K.; Huang, H. [College of Chemical Engineering and Materials Science, Zhejiang University of Technology, Hangzhou 310032 (China)

    2008-06-15

    Highly porous nickel oxide thin films were prepared on ITO glass by a simple chemical bath deposition (CBD) method in combination with a following heat-treatment process. XRD analysis revealed that the as-deposited precursor film contained {beta}-Ni(OH){sub 2} and {gamma}-NiOOH, and they changed to cubic polycrystalline NiO after annealing. The FTIR results showed presence of free hydroxyl ion and water in the NiO thin films. The electrochromic properties of NiO thin films were investigated in an aqueous alkaline electrolyte (1 M KOH) by means of transmittance, cyclic voltammetry (CV) and chronoamperometry (CA) measurements. The NiO thin film annealed at 300 C exhibited a noticeable electrochromism and good memory effect. The coloration efficiency was calculated to be 42 cm{sup 2} C{sup -1} at 550 nm, with a variation of transmittance up to 82%. The porous NiO thin films also showed good reaction kinetics with fast switching speed, and the coloration and bleaching time were 8 and 10 s, respectively. (author)

  17. Ciprofloxacin adsorption from aqueous solution onto chemically prepared carbon from date palm leaflets

    Institute of Scientific and Technical Information of China (English)

    El-Said Ibrahim El-Shafey; Haider Al-Lawati; Asmaa Soliman Al-Sumri

    2012-01-01

    A chemically prepared carbon was synthesized from date palm leaflets via sulphuric acid carbonization at 160℃.Adsorption of ciprofloxacin (CIP) from aqueous solution was investigated in terms of time,pH,concentration,temperature and adsorbent status (wet and dry).The equilibrium time was found to be 48 hr.The adsorption rate was enhanced by raising the temperature for both adsorbents,with adsorption data fitting a pseudo second-order model well.The activation energy,Ea,was found to be 17 kJ/mol,indicating a diffusion-controlled,physical adsorption process.The maximum adsorption was found at initial pH 6.The wet adsorbent showed faster removal with higher uptake than the dry adsorbent,with increased performance as temperature increased (25-45℃ ).The equilibrium data were found to fit the Langmuir model better than the Freundlich model.The thermodynamic parameters showed that the adsorption process is spontaneous and endothermic.The adsorption mechanism is mainly related to cation exchange and hydrogen bonding.

  18. Chemical and enzymatic preparation of acylglycerols containing C18 furanoid fatty acids.

    Science.gov (United States)

    Lie Ken Jie, M S; Syed-Rahmatullah, M S

    1995-01-01

    C18 furanoid triacylglycerol [glycerol tri-(9,12-epoxy-9,11-octadecadienoate)] was prepared by chemical transformation of triricinolein isolated from castor oil. The procedure involved oxidation, epoxidation and cyclization of the epoxy-keto intermediate with sodium azide and ammonium chloride in aqueous ethanol. The furanoid triacylglycerol was also obtained by esterification of C18 furanoid fatty acid with glycerol using Novozyme 435 (Novo Nordisk A.S., Bagsvaerd, Denmark) as biocatalyst. When Lipozyme (Novo Nordisk A.S.) was used, a mixture of the furanoid 1(3)-rac-monoacylglycerol and 1,3-diacylglycerol was obtained. In order to obtain the C18 furanoid 1,2(2,3)-diacylglycerol, selective hydrolysis of the furanoid triacylglycerol was achieved using porcine pancreatic lipase in tris(hydroxymethyl) methylamine buffer. Interesterification of triolein with methyl C18 furanoid ester in the presence of Lipozyme showed maximum incorporation of 34% of furanoid fatty acid. Extension of the interesterification to vegetable oils (olive, peanut, sunflower, corn and palm oil) allowed a maximum of 24% furanoid acid incorporation to be achieved. PMID:7760692

  19. Impedance spectroscopy of manganite films prepared by metalorganic chemical vapor deposition.

    Science.gov (United States)

    Nakamura, Toshihiro; Homma, Kohei; Tachibana, Kunihide

    2011-09-01

    Polycrystalline Pr(1-x)CaxMnO3 (PCMO) films were prepared by liquid source metalorganic chemical vapor deposition using in situ infrared spectroscopic monitoring. The electric properties of the PCMO-based devices with Ni and Al electrodes (Ni-PCMO-Ni and Al-PCMO-Al devices) were studied by dc current-voltage (I-V) measurements and ac impedance spectroscopy. The current varied linearly with the applied voltage in Ni-PCMO-Ni devices, while nonlinear behavior was observed in I-V curves for Al-PCMO-Al devices. Impedance spectra were also different between Ni-PCMO-Ni and Al-PCMO-Al devices. The Cole-Cole plots for the Ni-PCMO-Ni devices showed only a single semicircular arc, which was assigned to the PCMO bulk impedance. Impedance spectra for the Al-PCMO-Al devices had two distinct components, which could be attributed to the PCMO bulk and to the interface between the PCMO film and the Al electrode, respectively. The bias dependence of the impedance spectra suggested that the resistance switching in the Al-PCMO-Al devices was mainly due to the resistance change in the interface between the film and the electrode. The metal electrode plays an important role in the resistance switching in the PCMO-based devices. The choice of the optimum metal electrodes is essential to the ReRAM application of the manganite-based devices.

  20. Preparation and physico-chemical properties of hydrogels from carboxymethyl cassava starch crosslinked with citric acid

    Science.gov (United States)

    Boonkham, Sasikan; Sangseethong, Kunruedee; Chatakanon, Pathama; Niamnuy, Chalida; Nakasaki, Kiyohiko; Sriroth, Klanarong

    2014-06-01

    Recently, environmentally friendly hydrogels prepared from renewable bio-based resources have drawn significant attention from both industrial and academic sectors. In this study, chemically crosslinked hydrogels have been developed from cassava starch which is a bio-based polymer using a non-toxic citric acid as a crosslinking agent. Cassava starch was first modified by carboxymethylation to improve its water absorbency property. The carboxymethyl cassava starch (CMCS) obtained was then crosslinked with citric acid at different concentrations and reaction times. The gel fraction of hydrogels increased progressively with increasing citric acid concentration. Free swelling capacity of hydrogels in de-ionized water, saline solution and buffers at various pHs as well as absorption under load were investigated. The results revealed that swelling behavior and mechanical characteristic of hydrogels depended on the citric acid concentration used in reaction. Increasing citric acid concentration resulted in hydrogels with stronger network but lower swelling and absorption capacity. The cassava starch hydrogels developed were sensitive to ionic strength and pH of surrounding medium, showing much reduced swelling capacity in saline salt solution and acidic buffers.

  1. Low-cost plasmonic solar cells prepared by chemical spray pyrolysis

    Directory of Open Access Journals (Sweden)

    Erki Kärber

    2014-12-01

    Full Text Available Solar cells consisting of an extremely thin In2S3/CuInS2 buffer/absorber layer uniformly covering planar ZnO were prepared entirely by chemical spray pyrolysis. Au nanoparticles (Au-NPs were formed via thermal decomposition of a gold(III chloride trihydrate (HAuCl4·3H2O precursor by spraying 2 mmol/L of the aqueous precursor solution onto a substrate held at 260 °C. Current–voltage scans and external quantum efficiency spectra were used to evaluate the solar cell performance. This work investigates the effect of the location of the Au-NP layer deposition (front side vs rear side in the solar cell and the effect of varying the volume (2.5–10 mL of the sprayed Au precursor solution. A 63% increase (from 4.6 to 7.5 mA/cm2 of the short-circuit current density was observed when 2.5 mL of the precursor solution was deposited onto the rear side of the solar cell.

  2. Preparation and characterization of chemical gradient surfaces and their application for the study of cellular interaction phenomena

    NARCIS (Netherlands)

    Ruardy, TG; Schakenraad, JM; vanderMei, HC; Busscher, HJ

    1997-01-01

    Chemical gradient surfaces are surfaces with a gradually changing chemistry along their length which is responsible for a position bound variation in physical properties, most notably, the wettability. In this review, methods to prepare (palladium deposition, diffusion technique, density gradient me

  3. Preparation of highly porous carbonaceous sorbents from sewage sludge by physical and chemical activation

    Energy Technology Data Exchange (ETDEWEB)

    Ros, A.; Martin, M.J. [Girona Univ., Lab. d' Enginyerie Quimica i Ambiental, Dept. d' Enginyeria Quimica, Agraria i Tecnologia Agroalimentaria, Facultat de Ciencies (Spain); Lillo-Rodenas, M.A.; Linares-Solano, A. [Alicante Univ., Dept. de Quimica Inorganica (Spain); Fuente, E.; Montes-Moran, M.A. [Instituto Nacional del Carbon, CSIC, Oviedo (Spain)

    2005-07-01

    Among the different porous materials, activated carbon (AC) is the most widely used for environmental applications such as gas-phase pollutant removal, gas separation, solvent recovery and water purification, because of its high specific surfacea. Commercial activated carbons are generally produced from coals and lignocellulosic materials [1]. Additionally, in the latest years great attention is being focused on the reuse of wastes such as sewage sludges [2,3]. The objective of this study is to find more effective activating procedures to prepare AC from sewage sludge. Both dried sludges from two different WWTP (SL, SB) and their corresponding chars prepared by pyrolysis (SL-P, SB-P) were activated using physical activation (CO{sub 2}) and chemical activation (H{sub 3}PO{sub 4}, NaOH and KOH). As shown in Table 1, pyrolysis of the raw sludges slightly increased the specific surface area, up to 50 m{sup 2}/g. Acid-washing of the pyrolyzed samples with 5 M HCl removes part of the metal content leading to an increase in the specific surface areas for both SL-PD and SB-PD, with surface areas of 428 m{sup 2}/g and 188 m{sup 2}/g, respectively. This simple washing treatment is useful for the development of porous adsorbents, especially in the case of SL derived materials. Our results show that CO{sub 2} physical activation of the pyrolyzed and the HCl-washed samples develops no appreciable porosity in the final materials, under the experimental conditions used. For CO{sub 2} activation, maximum temperatures of 870 C and holding times up to 4 hours in CO{sub 2} (100 ml/min) were used. Chemical activation with H{sub 3}PO{sub 4} of the pristine samples and those pyrolyzed was performed at 450 C, a temperature typically used for the activation by H{sub 3}PO{sub 4} of lignocellulosic precursors, and using two different H{sub 3}PO{sub 4} solutions (30 and 50% wt). These conditions were not either suitable for an efficient porosity development. A detailed study about the

  4. NOVEL PREPARATION AND MAGNETO CHEMICAL CHARACTERIZATION OF NANOPARTICLE MIXED ALCOHOL CATALYSTS

    Energy Technology Data Exchange (ETDEWEB)

    Seetala V. Naidu; Upali Siriwardane

    2005-05-24

    We have developed and streamlined the experimental systems: (a) Laser-induced solution deposition (LISD) photosynthesis, ball-milling, and chemical synthesis of Fe, Co, and Cu nanoparticle catalysts; (b) Sol-gel method for mesoporous {gamma}-Al{sub 2}O{sub 3}, SiO{sub 2}, hybrid alumina/silica granular supports; (c) Three sol-gel/oil-drop catalyst preparation methods to incorporate metal nanoparticles into mesoporous 1 mm granular supports; (d) Low-cost GC-TCD system with hydrogen as carrier gas for the determination of wide spectrum of alkanes produced during the F-T reactions; and (e) Gas-flow reactor and microchannel reactor for fast screening of catalysts. The LISD method could produce Co, Cu, and Fe (5 nm) nanoparticles, but in milligram quantities. We could produce nanoparticles in gram quantities using high-energy ball milling and chemical synthesis methods. Ball milling gave wide particle size distribution compared to the chemical synthesis method that gave almost uniform size ({approx}5 nm) particles. Metal nanoparticles Cu, Co, Fe, Cu/Co, Cu/Fe and Co/Fe were loaded (2-12 wt%) uniformly into {gamma}-Al{sub 2}O{sub 3}, SiO{sub 2}, or alumina/silica hybrid supports by combined sol-gel/oil-drop methods followed by calcination and hydrogenation steps, prior to syngas FT reaction studies. The properties of metal loaded {gamma}-Al{sub 2}O{sub 3} granules were compared for the two precursors: aluminum tri-sec-butoxide (ALTSB) and aluminum tri-iso-propoxide (ALTIP). The effect of solgel supports alumina, silica, and alumina/silica hybrid were examined on catalytic properties. Metal loading efficiencies for pure metal catalysts increased in the order Co, Cu and Fe in agreement with solubility of metal hydroxides. In case of mixed metals, Co and Cu seams to interfere and reduce Fe metal loading when metal nitrate solutions are used. The solubility differences of metal hydroxides would not allow precise control of metal loading. We have overcome this problem by

  5. An Alternative Way towards Preparation of Hydrophobically Associating Polyacrylamide:Chemical Post-Modification

    Institute of Scientific and Technical Information of China (English)

    FENG Yu-jun

    2004-01-01

    Hydrophobically associating polyacrylamides (HAPAMs) are derivatives from polyacrylamides by incorporating a small amount of hydrophobic moieties along the water-soluble mainchain. They are now becoming a class of promising candidates as thickeners or rheology modifiers in the formulations where rheology is necessary to be regulated, such as tertiary oil recovery, drilling fluids, hydraulic fracturing and coatings. Due to association of hydrophobes in nano-domains, their aqueous solutions exhibit very interesting rheological properties and better stability against salts than the unmodified precursor, polyacrylamide.Generally, there are two synthetic routes to introduce hydrophobic portion onto water-soluble polymer chains; i.e., direct copolymerization of hydrophobic and hydrophilic monomers, and post-polymerization functionalization[1]. In the case of HAPAM polymers, a commonly accepted method is micellar copolymerization in which an appropriate surfactant is employed to solubilize both monomers. However, it is widely reported[2] that the obtained polymers via micellar polymerization are characterized by: (i) blocky distribution of the hydrophobes; (ii) compositional inhomogeneity and (iii) strong dependence of solution properties on the block length.In this work, the alternative process, i.e., chemical post-modification, is employed to synthesize HAPAM polymers by direct N-alkylation of parent polyacrylamide (Figure 1) in dimethyl sulfoxide[3,4].PAM HAPAMFig. 1 Schematic route to prepare HAPAM by direct N-alkylation of PAMIt is found that the final incorporation of hydrophobic groups is in good agreement with the feed ratio[4], in contrast with that from micellar copolymerization which always brings about composition drift. Furthermore, unique rheological responses to shear rate, salt, temperature are also evidenced[5].

  6. High coercivity Gd-substituted Ba hexaferrites, prepared by chemical coprecipitation

    Science.gov (United States)

    Litsardakis, G.; Manolakis, I.; Serletis, C.; Efthimiadis, K. G.

    2008-04-01

    A series of Gd-substituted Ba hexaferrites with nominal formula (Ba1-xGdx)Oṡ5.25 Fe2O3 (x=0-0.30) were prepared by the chemical coprecipitation method from nitrate precursors and heating at T =800-1200°C for 2h. The samples have been examined by x-ray diffraction, vibrating-sample magnetometer, and scanning electron microscopy methods. Gd substituted samples form single phase materials with the M-type hexaferrite structure at all heating temperatures, in the range of x ⩽0.10-0.20. The saturation magnetization (at 1.8T) varies slightly with x in most cases and, for x =0.05-0.10, it increases up to 66.7Am2/kg, exceeding the value of the unsubstituted hexaferrite. A strong enhancement of the coercivity is observed for all substituted samples, with maximum values Hc=457kA/m for the single-phase x =0.10 sample annealed at 1000°C and Hc=477kA/m for the x =0.25 sample annealed at 1100°C which contains Fe2O3 and GdFeO3 impurities. As the variation of coercivity with either substitution rate (x ) or annealing temperature is not monotonic, three different factors may account for the high coercivities that are obtained: (a) an inhibition of grain growth due to the presence of Gd, (b) a possible inherent effect on magnetocrystalline anisotropy, especially for single phase samples, and (c) a microstructural effect of secondary phases.

  7. Extended phase homogeneity and electrical properties of barium calcium titanate prepared by the wet chemical methods

    International Nuclear Information System (INIS)

    Ca-substituted BaTiO3 with extended homogeneity range upto ∼50 mol% CaTiO3 have been prepared by three different chemical routes namely carbonate-oxalate (COBCT), gel-carbonate (GCBCT), and gel-to-crystallite conversion (GHBCT) followed by heat treatment above 1150 deg. C. X-ray powder diffraction (XRD) data show continuous decrease in the tetragonal unit cell parameters as well as c0/a0 ratio with CaTiO3 content, which are in accordance with the substitution of smaller sized Ca2+ ions at the barium sites. The microstructure as well as the dielectric properties are greatly influenced by the cationic ratio, α=(Ba+Ca)/Ti. The grain size decreases with CaTiO3 content for the stoichiometric samples (α=1), whereas ultrafine microstructure is observed in the case of off-stoichiometric samples (α>1) for the whole compositional range of CaTiO3 concentrations. Sharper εr-T characteristics at lower calcium content and broader εr-T with decreased εmax, in the higher calcium range are observed in the case of α=1. Whereas nanometer grained ceramics exhibiting diffuse εr-T characteristics are obtained in the case of α>1. The positive temperature coefficient of resistivity (PTCR) is realized for barium calcium titanate ceramics having 0.3 at.% Sb as the donor dopant for higher CaTiO3 (typically 30 mol%) containing samples (α=1), indicating that Ca2+ ions do not behave as acceptors if they were to substitute at the Ti4+ sites. Whereas the off-stoichiometric (α>1) ceramics retained high resistivity, indicative of the Ti-site occupancy for Ca2+ in fine grain ceramics

  8. Lipid nanocarriers containing ester prodrugs of flurbiprofen preparation, physical-chemical characterization and biological studies.

    Science.gov (United States)

    Bondìl, M L; Craparo, E F; Picone, P; Giammona, G; Di Gesù, R; Di Carlo, M

    2013-02-01

    In this paper, the preparation, chemical-physical, technological and in vitro characterization of nanostructured lipid carriers (NLC) carrying R-flurbiprofen ester prodrugs, were analyzed for a potential pharmaceutical application. R-flurbiprofen was chosen as a model drug because it has been found to play an effective role in counteracting secretases involved in neurodegenerative diseases, although it does not cross the Blood Brain Barrier (BBB). In this study, two R-flurbiprofen ester prodrugs (ethyl and hexyl) were successfully synthesized and entrapped into non-pegylated and pegylated NLC. The obtained systems showed average diameters in the colloidal size range, negative zeta potential values and a good loading capacity. Drug release studies in physiological media on all drug-loaded samples showed a controlled drug release both at at pH 7.4 (containing esterase or not) and in human plasma of each ester prodrug, with a complete hydrolysis to R-flurbiprofen in media containing esterase. Empty and ethyl prodrug-loaded NLC were also demonstrated to have no cytotoxicity on human neuroblastoma (LAN5) cells, while hexyl prodrug-loaded NLC caused a reduction of cell viability probably due to a better capability of prodrug-loaded NLC to cross the cell membrane than the free compounds. These data were confirmed by microscopical observation, in which only the cells treated with hexyl prodrug-loaded NLC showed morphological changes. Outcoming data suggest that NLC could be potential carriers for parenteral administration of ethyl ester of R-flurbiprofen in the treatment of neurodegenerative diseases such as Alzheimer's.

  9. Plasma chemical reduction of model corrosion brass layers prepared in soil

    Science.gov (United States)

    Radkova, Lucie; Mikova, Petra; Prikryl, Radek; Krcma, Frantisek

    2016-08-01

    The brass plates of (50 × 10 × 1) mm3 were prepared with model corrosion layer because the real archaeological artifacts could be damaged during the method optimization. Samples corroded naturally more than 2 years in the soil. Excavated samples were treated in the low pressure (150 Pa) quartz glass plasma reactor (90 cm long and 9.5 cm in diameter) which was surrounded by two external copper electrodes supplied by radio-frequency generator (13.56 MHz). The experiments were carried out in a hydrogen-argon gas mixture at mass flows of 30 sccm for hydrogen and 20 sccm for argon for 90 min. The plasma power was 100, 200, 300 and 400 W in continuous and pulsed mode. Maximum sample temperature was set at 120 °C. The whole process was monitored by optical emission spectroscopy and the obtained data were used to calculate the relative intensity of OH radicals and rotational temperature. The results showed that the higher power had the greater maximum intensity of the OH radicals and rapidly degraded the corrosion layer. Corrosion layer was not completely removed during the reduction, but due to the reactions which occur in the plasma corrosion layer became brittle and after plasma chemical treatment can be removed easily. Finally, the SEM-EDX analysis of the surface composition confirmed removal of chlorine and oxygen from the corrosion products layers. Contribution to the topical issue "6th Central European Symposium on Plasma Chemistry (CESPC-6)", edited by Nicolas Gherardi, Ester Marotta and Cristina Paradisi

  10. SrAl2O4 :Eu2+, Dy3+ Long Afterglow Phosphors Prepared by Chemical Coprecipitation Method

    Institute of Scientific and Technical Information of China (English)

    Sun Yanbin; Qiu Guanming; Zhang Shengqu; Zhang Ming; Yan Changhao; Dai Shaojun

    2004-01-01

    SrAl2 O4: Eu2+ , Dy3+ long afterglow phosphors were prepared by chemical coprecipitation method. Ammonium carbonate and ammonium hydrogen carbonate were used as the precipitants. The preparation of the SrAl2 O4: Eu2+ ,Dy3 + precursor was completed at room temperature by controlling the concentration of the metal-salt solution, pH value of the system, etc. The phosphors were prepared by sintering the precursor at 1000 ~ 1200 ℃ in a weak reducing atmosphere for 2 h. The XRD, SEM, excitation spectra, emission spectra and afterglow decay of the samples were tested and the optimal synthesis conditions of the SrAl2O4: Eu2+ , Dy3+ long afterglow phosphors prepared by precipitation method were determined. The phosphor which had good luminescent properties is prepared and its persistent time can reach more than 1600 min. In the coprecipitation process, a small amount of glucose operates to refe the luminescent powders. The particle size of the phosphor can be less than 1 μm. The sintering temperature of the sample prepared by the coprecipitation method is much lower than that of the one prepared by the high temperature solid state method.Compared with the high temperature solid state method, a clear blue shift occurs in the excitation and emission spectra of the samples.

  11. Chemical synthesis of 5-azacytidine nucleotides and preparation of tRNAs containing 5-azacytidine in its 3'-terminus.

    OpenAIRE

    Zielinski, W S; Sprinzl, M.

    1984-01-01

    5-azacytidine-5'-triphosphate prepared from 5-azacytidine by chemical phosphorylation is a substrate for AMP (CMP) tRNA nucleotidyl transferase from yeast. tRNAsPhe from yeast containing 5-azacytidine in their 3'-termini were prepared enzymatically. tRNAPhe-Cpn5CpA and tRNAPhe-n5Cpn5CpA can be aminoacylated by phenylalanyl-tRNA synthetase from yeast and they are active in the poly(U)-dependent synthesis of poly(Phe) on E. coli ribosomes. The decomposition of 5-azacytidine via hydrolysis of th...

  12. CHEMICAL ANALYSIS OF NIRGUNDI TAILA WITH SPECIAL REFERENCE TO PREPARATION IN DIFFERENT NUMBER OF DAYS

    OpenAIRE

    Prashanth B K; Rao K Shankar; Krishnamurthy M.S; Rao Ravi; Bhat Smitha

    2012-01-01

    Sneha kalpana is a process where the active principles present in the drug are extracted with the Sneha (Ghee or Oil) during the pharmaceutical process. The method of preparation of different Taila kalpanas requires different Drava dravyas and different number of days for the paka. Nirgundi taila as said in Charaka Samhita Chikitsa sthana 28/134 was prepared with Tila taila as the base. The three different oil samples were prepared by adding Nirgundi Patra Swarasa as the drava dravya. The sam...

  13. Effects of Heating Processing on Microstructure and Magnetic Properties of Mn-Zn Ferrites Prepared via Chemical Co-precipitation

    Institute of Scientific and Technical Information of China (English)

    CHEN Shijie; XIA Jingbing; DAI Jianqing

    2015-01-01

    The fine powders of Mn-Zn ferrites with uniform size were prepared via chemical co-precipitation method. X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), frequency dependence of permeability and metallographical microscope were used to investigate the crystal structure, surface topography and magnetic properties of the powders and the sintering samples. The experimental results demonstrate that the precursor powders have formed a pure phase cubic spinel MnxZn1-xFe2O4 while in the reactor and show deifnite magnetism, which can solve the dififcult issue in washing process effectively. When calcined beneath 450℃, the powders have intact crystal form and the crystallite size is less than 20 nm. Comparison tests of sintering temperatures show that 1 300℃ is the ideal sintering temperature for Mn-Zn ferrites prepared by using the chemical co-precipitation.

  14. Study on Physical and Chemical Behaviors of Rare Earths in Preparing Ceramic Tube Supported Palladium Film by Electroless Plating

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The rare earths of ytterbium, lanthanum, praseodymium, neodymium and their binary mixtures were respectively added into the traditional electroless plating solution to prepare thin palladium film on the inner surface of porous ceramic tube. The experimental results shows that the addition of rare earths increases palladium deposition rates and the binary mixtures are superior to the single rare earths and the mixture of ytterbium-lanthanum is the most efficient. Adding the mixture of ytterbium-lanthanum can also reduce the plating temperature by 10~20 ℃, shrink the metal crystal size and improve the film densification compared to those by traditional electroless plating. A thin palladium film with 5 μm was prepared and the film made a highly pure hydrogen with a molar fraction of more than 99.97% from a H2-N2 gas mixture. More attentions were paid to analyze the physical and chemical behaviors of the rare earths in palladium film preparation.

  15. Characterizations on the microstructures of LiMn2O4 prepared by a simple soft-chemical technique

    International Nuclear Information System (INIS)

    LiMn2O4 powders were prepared by a simple soft-chemical technique at different temperatures. X-ray diffraction and thermogravimetric analysis suggested that the material prepared at 800 deg. C was stoichiometric LiMn2O4, whereas those prepared at 600 and 700 deg. C were Li[Mn0.773+Mn1.234+]O4.115 and Li[Mn0.853+Mn1.154+]O4.075. Several typical XRD peaks of the compounds were investigated with an aim to elucidate (i) the Li immigration to the 16d octahedral sites, (ii) the partial tetragonal phase transition of the material and (iii) the mean coherent domain size and microstrain. SEM study showed that the particle size of the materials increased with heating temperature. The activation energy for the material particle growth was determined as 30.4 kJ mol-1

  16. Final status report in preparation for the chemical cleaning of Dresden-1, DNS-D1-034

    International Nuclear Information System (INIS)

    This report discusses the status of all of the activities conducted in preparation for the chemical cleaning of the Dresden-1 Nuclear Power Plant of Commonwealth Edison of Illinois. The metallurgical testing of a solvent and its ability to remove radioactivity are reviewed. Included are all engineering details relating to the modifications to the primary system to be able to perform the chemical cleaning and to rinse the cleaning solvent out of the equipment. A facility to store and process spent cleaning solutions is described in detail. Construction activities and preoperational activities are recounted. Licensing activities, quality assurance, safety, and radiation protection are discussed. The report includes recommendations for future actions for restarting the project when approval is received. All of the efforts discussed in this Final Status Report led to the conclusion that the chemical cleaning, as planned, was feasible. All of the necessary modifications and new equipment are in place and are operational

  17. Sol-gels with fiber-optic chemical sensor potential: Effects of preparation, aging, and long-term storage

    Science.gov (United States)

    Badini, G. E.; Grattan, K. T. V.; Tseung, A. C. C.

    1995-08-01

    The features of sol-gels, incorporating pH-sensitive dyes, designed as potential substrates for fiber-optic chemical sensors, have been investigated in terms of a variety of characteristics resulting from the preparation methods used and following the storage of samples for a period of several years. These materials, organically doped sol-gels, have been used as the heart of a number of prototype chemical sensing instruments, and a key issue in their effective use in instrumentation is their long-term durability and stability. In this work, it has been shown that such aged gel substrates can withstand immersion in water, drying, and reimmersion without fragmenting. Such impregnated gels were shown to still exhibit strong fluorescence, although some changes to the gel structure, determined from microhardness measurements, were observed and reported, reflecting their potential for use in chemically sensitive fiber optic-based instruments.

  18. Magnetic properties of lanthanum orthoferrite fine powders prepared by different chemical routes

    Indian Academy of Sciences (India)

    Benedict Ita; P Murugavel; V Ponnambalam; A R Raju

    2003-10-01

    Fine powders of lanthanum iron oxide, LaFeO3, have been prepared by solid state reaction as well as sol-gel synthesis and nebulized spray pyrolysis. Structures, morphologies and magnetic susceptibility measurements of these powders have been examined. The powders prepared by all the three low-temperature routes contain nearly spherical particles with an average diameter of 40 nm. These samples show a lower Neel temperature than the powder prepared by solid state reaction besides showing much lower magnetic susceptibility at low temperatures.

  19. Growth and properties of few-layer graphene prepared by chemical vapor deposition

    OpenAIRE

    Park, Hye Jin; Meyer, Jannik; Roth, Siegmar; Skakalova, Viera

    2009-01-01

    The structure, and electrical, mechanical and optical properties of few-layer graphene (FLG) synthesized by chemical vapor deposition (CVD) on a Ni coated substrate were studied. Atomic resolution transmission electron microscope (TEM) images show highly crystalline single layer parts of the sample changing to multilayer domains where crystal boundaries are connected by chemical bonds. This suggests two different growth mechanisms. CVD and carbon segregation participate in the growth process ...

  20. Design, preparation, and structure of particle preforms for Si3N4(P)/Si3N4 radome composites prepared using chemical vapor infiltration process

    Institute of Scientific and Technical Information of China (English)

    Yongsheng Liu; Laifei Cheng; Litong Zhang; Yongdong Xu; Yi Liu

    2008-01-01

    A particle preform was designed and prepared by conglomerating and cold-pressed process, which was condensed by chemical vapor infiltration (CVI) process to fabricate silicon nitride particles reinforced silicon nitride composites. The conglomera-tions are of almost sphericity after conglomerated. There are large pores among the conglomerations and small pores within them-selves in the preform according to the design and the test of pore size distribution. The pore size of the preform is characterized by a double-peak distribution. The pore size distribution is influenced by conglomeration size. large pores among the conglomerations still exist after infiltrated Si3N4 maul. The conglomerations, however, are very compact. The CVI Si3N4 looks like cauliflower-shaped structure.

  1. Magnetically assisted chemical separation (MACS) process: Preparation and optimization of particles for removal of transuranic elements

    International Nuclear Information System (INIS)

    The Magnetically Assisted Chemical Separation (MACS) process combines the selectivity afforded by solvent extractants with magnetic separation by using specially coated magnetic particles to provide a more efficient chemical separation of transuranic (TRU) elements, other radionuclides, and heavy metals from waste streams. Development of the MACS process uses chemical and physical techniques to elucidate the properties of particle coatings and the extent of radiolytic and chemical damage to the particles, and to optimize the stages of loading, extraction, and particle regeneration. This report describes the development of a separation process for TRU elements from various high-level waste streams. Polymer-coated ferromagnetic particles with an adsorbed layer of octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) diluted with tributyl phosphate (TBP) were evaluated for use in the separation and recovery of americium and plutonium from nuclear waste solutions. Due to their chemical nature, these extractants selectively complex americium and plutonium contaminants onto the particles, which can then be recovered from the solution by using a magnet. The partition coefficients were larger than those expected based on liquid[liquid extractions, and the extraction proceeded with rapid kinetics. Extractants were stripped from the particles with alcohols and 400-fold volume reductions were achieved. Particles were more sensitive to acid hydrolysis than to radiolysis. Overall, the optimization of a suitable NMCS particle for TRU separation was achieved under simulant conditions, and a MACS unit is currently being designed for an in-lab demonstration

  2. Magnetically assisted chemical separation (MACS) process: Preparation and optimization of particles for removal of transuranic elements

    Energy Technology Data Exchange (ETDEWEB)

    Nunez, L.; Kaminski, M.; Bradley, C.; Buchholz, B.A.; Aase, S.B.; Tuazon, H.E.; Vandegrift, G.F. [Argonne National Lab., IL (United States); Landsberger, S. [Univ. of Illinois, Urbana, IL (United States)

    1995-05-01

    The Magnetically Assisted Chemical Separation (MACS) process combines the selectivity afforded by solvent extractants with magnetic separation by using specially coated magnetic particles to provide a more efficient chemical separation of transuranic (TRU) elements, other radionuclides, and heavy metals from waste streams. Development of the MACS process uses chemical and physical techniques to elucidate the properties of particle coatings and the extent of radiolytic and chemical damage to the particles, and to optimize the stages of loading, extraction, and particle regeneration. This report describes the development of a separation process for TRU elements from various high-level waste streams. Polymer-coated ferromagnetic particles with an adsorbed layer of octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide (CMPO) diluted with tributyl phosphate (TBP) were evaluated for use in the separation and recovery of americium and plutonium from nuclear waste solutions. Due to their chemical nature, these extractants selectively complex americium and plutonium contaminants onto the particles, which can then be recovered from the solution by using a magnet. The partition coefficients were larger than those expected based on liquid[liquid extractions, and the extraction proceeded with rapid kinetics. Extractants were stripped from the particles with alcohols and 400-fold volume reductions were achieved. Particles were more sensitive to acid hydrolysis than to radiolysis. Overall, the optimization of a suitable NMCS particle for TRU separation was achieved under simulant conditions, and a MACS unit is currently being designed for an in-lab demonstration.

  3. 21 CFR 1308.23 - Exemption of certain chemical preparations; application.

    Science.gov (United States)

    2010-04-01

    ... concentration that the packaged quantity does not present any significant potential for abuse (the type of..., quantity, proportion, or concentration, that the preparation or mixture does not present any potential for... permit any interested person to file written comments on or objections to the order within 60 days of...

  4. Nanoglass Fe79B21 powders prepared by chemical reduction: a low-temperature mossbauer study

    DEFF Research Database (Denmark)

    Wu, G.Y.; Jiang, Jianzhong; Lin, X.P.

    1999-01-01

    The magnetic behavior of nanoglass Fe79B21 powder has been investigated by Mossbauer spectroscopy in a temperature range from 5 to 295 K together with one amorphous Fe80B20 ribbon prepared by melt-spinning. It is found that average hyperfine fields for the powder sample are smaller than those for...

  5. Chemical Oxidative Polymerization of Polyaniline: A Practical Approach for Preparation of Smart Conductive Textiles

    Science.gov (United States)

    Abu-Thabit, Nedal Y.

    2016-01-01

    Electrically conducting polymers are one of the promising alternative materials for technological applications in many interdisciplinary areas, including chemistry, material sciences, and engineering. This experiment was designed for providing undergraduate students with a quick and practical approach for preparation of a polyaniline-conducting…

  6. Hydrogenation of Furfural to Furfuryl Alcohol over Co-B Amorphous Catalysts Prepared by Chemical Reduction in Variable Media

    Institute of Scientific and Technical Information of China (English)

    LI, Hui; CHAI, Wei-Mei; LUO, Hong-Shan; LI, He-Xing

    2006-01-01

    Five Co-B amorphous alloy catalysts were prepared by chemical reduction in different media, including pure water and pure ethanol as well as the mixture of ethanol and water with variable ethanol content. Their catalytic properties were evaluated using liquid phase furfural hydrogenation to furfuryl alcohol as the probe reaction. It was found that the reaction media had no significant influence on either the amorphous structure of the Co-B catalyst or the electronic interaction between metallic Co and alloying B. This could successfully account for the fact that all the as-prepared Co-B catalysts exhibited almost the same selectivity to furfuryl alcohol and the same activity per surface area ( RSH ), which could be considered as the intrinsic activity, since the nature of active sites remained unchanged. However, the activity per gram of Co ( RmH ) of the as-prepared Co-B catalysts increased rapidly when the ethanol content in the water-ethanol mixture used as the reaction medium for catalyst preparation increased. This could be attributed to the rapid increase in the surface area possibly owing to the presence of more oxidized boron species which could serve as a support for dispersing the Co-B amorphous alloy particles.

  7. Silver nanoparticles prepared by chemical reduction-protection method, and their application in electrically conductive silver nanopaste

    Energy Technology Data Exchange (ETDEWEB)

    Liu Jianguo, E-mail: ljg712@yahoo.com.c [Wuhan National Laboratory for Optoelectronics, College of Optoelectronics Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); Li Xiangyou; Zeng Xiaoyan [Wuhan National Laboratory for Optoelectronics, College of Optoelectronics Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China)

    2010-04-02

    Ag nanoparticles were prepared in a water-phase system with a mixture of silver-ammonia complex, sodium borohydride, and lauric acid according to molar feed ratio of approximately 6:3:1. The mechanism of preparation and separation by chemical reduction-protection method was explored. The as-synthesized Ag nanoparticles were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and UV-vis spectroscopy, respectively. It was found that the size of high purity Ag particles was ranging from 30 to 50 nm with slight agglomeration. In addition, the as-synthesized wet Ag nanoparticles were dispersed stably in organic vehicle to formulate electrically conductive nanopaste. Upon direct-written and sintered, the array pattern of the nanopaste with the resolution of about 30 {mu}m was achieved with the electrical resistivity in the order of magnitude of 10{sup -5} {Omega} cm.

  8. The preparation of low electroendosmosis agarose and its physico-chemical property

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Studies on Gelidium amansii agar fractionations were carried out in this paper. Gelidium amansii agar was fractionated on DEAE-Cellulose, and four fractions were obtained sequentially. The fractions were analyzed on physical and chemical properties, and IR and 13C-NMR spectroscopy applied for elucidating the chemical structure. Among the four fractions obtained, water fraction measured up to the standard of low EEO agarose. The sulfate content, ash content, electroendosmosis and gel strength(1%) of water fraction were 0.16%, 0.34%, 0.12 and 1 130g/cm2 respectively, similar to those of the Sigma products.

  9. Morphology of carbon nanotubes prepared via chemical vapour deposition technique using acetylene: A small angle neutron scattering investigation

    Indian Academy of Sciences (India)

    D Sen; K Dasgupta; J Bahadur; S Mazumder; D Sathiyamoorthy

    2008-11-01

    Small angle neutron scattering (SANS) has been utilized to study the morphology of the multi-walled carbon nanotubes prepared by chemical vapour deposition of acetylene. The effects of various synthesis parameters like temperature, catalyst concentration and catalyst support on the size distribution of the nanotubes are investigated. Distribution of nanotube radii in two length scales has been observed. The number density of the smaller diameter tubes was found more in number compared to the bigger one for all the cases studied. No prominent scaling of the structure factor was observed for the different synthesis conditions.

  10. Application of phase equilibria and chemical thermodynamics to the preparation, farbiration, and performance of advanced fast reactor fuel materials

    International Nuclear Information System (INIS)

    Described are some phase equilibria and chemical thermodynamics of systems relevant to the production and operation of the so-called ''advanced'' fast breeder reactor fuels. The systems discussed include UPu carbides, nitrides, oxycarbides and carbonitrides. Some examples of the application of these phase equilibria to the preparation, fabrication and behaviour of the materials in temperature gradients appropriate to reactor conditions are presented. Finally, aspects of the complex four and five component, U-C-O-N and U-Pu-C-O-N systems are discussed, a detailed knowledge of which is required for an analysis of advanced fuel behaviour

  11. Preparation of Nano-Particles (Pb,La)TiO3 Thin Films by Liquid Source Misted Chemical Deposition

    Institute of Scientific and Technical Information of China (English)

    张之圣; 曾建平; 李小图

    2004-01-01

    Nano-particles lanthanum-modified lead titanate (PLT) thin films are grown on Pt/Ti/SiO2/Si substrate by liquid source misted chemical deposition (LSMCD). PLT films are deposited for 4-8 times, and then annealed at various temperature. XRD and SEM show that the prepared films have good crystallization behavior and perovskite structure. The crystallite is about 60 nm. The deposition speed is 3 nm/min. This deposition method can exactly control stoichiometry ratios, doping concentration ratio and thickness of PLT thin films. The best annealing process is to bake at 300 ℃ for 10 min and anneal at 600 ℃ for 1 h.

  12. Preparation of nano-sized magnetic particles from spent pickling liquors by ultrasonic-assisted chemical co-precipitation.

    Science.gov (United States)

    Tang, Bing; Yuan, Liangjun; Shi, Taihong; Yu, Linfeng; Zhu, Youchun

    2009-04-30

    The aim of this study is to develop a new method for the preparation of high-value, environmentally friendly products from spent pickling liquors. An ultrasound treatment was introduced into a chemical co-precipitation process to control the size of the particles produced. The particles were characterized by X-ray powder diffraction and transmission electron microscopy. The magnetic parameter was measured with a magnetic property measurement system. The product consisted of ferrous ferrite (Fe(3)O(4)) nano-sized cubic particles with a high level of crystallinity that exhibited super-paramagnetism. PMID:18762377

  13. Chemical modifiers in electrothermal atomic absorption determination of Platinum and Palladium containing preparations in blood serum

    Directory of Open Access Journals (Sweden)

    Аntonina Alemasova

    2012-11-01

    Full Text Available The biological liquids matrixes influence on the characteristic masses and repeatability of Pt and Pd electrothermal atomic absorption spectroscopy (ETAAS determination was studied. The chemical modifiers dimethylglyoxime and ascorbic acid for matrix interferences elimination and ETAAS results repeatability improvement were proposed while bioliquids ETAAS analysis, and their action mechanism was discussed.

  14. Chemical characterization of lignin preparations of fresh and decomposing Spartina anglica by pyrolysis mass spectrometry

    NARCIS (Netherlands)

    Klap, V.A.; Boon, J.J.; Hemminga, M.A.; Van Soelen, J.

    1998-01-01

    In order to determine terrestrial contributions to the organic matter pool in the marine environment, a reliable chemical tracer is required. Lignin, an abundant component of vascular plant tissue is often used as such. In this study the lignin moiety of both fresh and degraded tissue of the model h

  15. Error sensitivity to environmental noise in quantum circuits for chemical state preparation

    CERN Document Server

    Sawaya, Nicolas P D; McClean, Jarrod R; Aspuru-Guzik, Alán

    2016-01-01

    Calculating molecular energies is likely to be one of the first useful applications to achieve quantum supremacy, performing faster on a quantum than a classical computer. However, if future quantum devices are to produce accurate calculations, errors due to environmental noise and algorithmic approximations need to be characterized and reduced. In this study, we use the high performance qHiPSTER software to investigate the effects of environmental noise on the preparation of quantum chemistry states. We simulate nineteen 16-qubit quantum circuits under environmental noise, each corresponding to a unitary coupled cluster state preparation of a different molecule or molecular configuration. Additionally, we analyze the nature of simple gate errors in noise-free circuits of up to 40 qubits. We find that the Jordan-Wigner (JW) encoding produces consistently smaller errors under a noisy environment as compared to the Bravyi-Kitaev (BK) encoding. For the JW encoding, pure-dephasing noise is shown to produce substa...

  16. Epitaxial graphene prepared by chemical vapor deposition on single crystal thin iridium films on sapphire

    OpenAIRE

    Vo-Van, Chi; Kimouche, Amina; Reserbat-Plantey, Antoine; Fruchart, Olivier; Bayle-Guillemaud, Pascale; Bendiab, Nedjma; Coraux, Johann

    2011-01-01

    To appear in Appl. Phys. Lett.; International audience; Uniform single layer graphene was grown on single-crystal Ir films a few nanometers thick which were prepared by pulsed laser deposition on sapphire wafers. These graphene layers have a single crystallographic orientation and a very low density of defects, as shown by diffraction, scanning tunnelling microscopy, and Raman spectroscopy. Their structural quality is as high as that of graphene produced on Ir bulk single crystals, \\textit{i....

  17. Some physico-chemical and radiation properties of plutonium-238 metal prepared by electrochemical amalgamation

    International Nuclear Information System (INIS)

    Pu-238 metal was prepared by electrolytic amalgamation from Pu(III) acetate aqueous solution and by followed by the thermal decomposition of the Pu amalgam. The density, specific heat power, γ-spectra, neutron flux, and corrosion kinetics in dry air at ambient temperature of the prepared 238Pu metal were measured. The neutron flux and γ-spectra from 238Pu metal have been attributed to spontaneous and induced fission and to (α,α'γ), (α,pγ), and (α,nγ) nuclear reactions on light nuclei. The electrochemically prepared 238Pu metal was shown to generate fewer neutrons, produce less gamma radiation, and contains lower 10B, 19F, and 28Si impurities in comparison with biomedical 238PuO2. The increase of neutron flux from the sample due to the reaction 18O(α,nγ) 21Ne was shown to be proportional to the increase of the mass of the 238Pu metal with time due to corrosion in dry air. 238Pu metal corrosion rate maximum and average values (1.1 x 10-2 and 4.7 x 10-3 mg cm-2 h-1, respectively) obtained in dry air were an order of magnitude higher than the rates published for 239Pu under similar experiment conditions. The difference between the 239Pu and 238Pu metal corrosion rate and mechanism is proposed to be due to the greater radiation effects and temperature on the 238Pu surface

  18. Error Sensitivity to Environmental Noise in Quantum Circuits for Chemical State Preparation.

    Science.gov (United States)

    Sawaya, Nicolas P D; Smelyanskiy, Mikhail; McClean, Jarrod R; Aspuru-Guzik, Alán

    2016-07-12

    Calculating molecular energies is likely to be one of the first useful applications to achieve quantum supremacy, performing faster on a quantum than a classical computer. However, if future quantum devices are to produce accurate calculations, errors due to environmental noise and algorithmic approximations need to be characterized and reduced. In this study, we use the high performance qHiPSTER software to investigate the effects of environmental noise on the preparation of quantum chemistry states. We simulated 18 16-qubit quantum circuits under environmental noise, each corresponding to a unitary coupled cluster state preparation of a different molecule or molecular configuration. Additionally, we analyze the nature of simple gate errors in noise-free circuits of up to 40 qubits. We find that, in most cases, the Jordan-Wigner (JW) encoding produces smaller errors under a noisy environment as compared to the Bravyi-Kitaev (BK) encoding. For the JW encoding, pure dephasing noise is shown to produce substantially smaller errors than pure relaxation noise of the same magnitude. We report error trends in both molecular energy and electron particle number within a unitary coupled cluster state preparation scheme, against changes in nuclear charge, bond length, number of electrons, noise types, and noise magnitude. These trends may prove to be useful in making algorithmic and hardware-related choices for quantum simulation of molecular energies. PMID:27254482

  19. Evaluation of Chemical Preparation on Insect Wing Shape for Geometric Morphometrics

    OpenAIRE

    Lorenz, Camila; Suesdek, Lincoln

    2013-01-01

    Geometric morphometrics is an approach that has been increasingly applied in studies with insects. A limiting factor of this technique is that some mosquitoes have wings with dark spots or many scales, which jeopardizes the visualization of landmarks for morphometric analysis. Recently, in some studies, chemically treatment (staining) of the wings was used to improve the viewing of landmarks. In this study, we evaluated whether this method causes deformation of the wing veins and tested wheth...

  20. Ionic Liquids and Cellulose: Dissolution, Chemical Modification and Preparation of New Cellulosic Materials

    Directory of Open Access Journals (Sweden)

    Mehmet Isik

    2014-07-01

    Full Text Available Due to its abundance and a wide range of beneficial physical and chemical properties, cellulose has become very popular in order to produce materials for various applications. This review summarizes the recent advances in the development of new cellulose materials and technologies using ionic liquids. Dissolution of cellulose in ionic liquids has been used to develop new processing technologies, cellulose functionalization methods and new cellulose materials including blends, composites, fibers and ion gels.

  1. Enamels in stained glass windows: Preparation, chemical composition, microstructure and causes of deterioration

    International Nuclear Information System (INIS)

    Stained glass windows incorporating dark blue and purple enamel paint layers are in some cases subject to severe degradation while others from the same period survived the ravages of time. A series of dark blue, green-blue and purple enamel glass paints from the same region (Northwestern Europe) and from the same period (16-early 20th centuries) has been studied by means of a combination of microscopic X-ray fluorescence analysis, electron probe micro analysis and transmission electron microscopy with the aim of better understanding the causes of the degradation. The chemical composition of the enamels diverges from the average chemical composition of window glass. Some of the compositions appear to be unstable, for example those with a high concentration of K2O and a low content of CaO and PbO. In other cases, the deterioration of the paint layers was caused by the less than optimal vitrification of the enamel during the firing process. Recipes and chemical compositions indicate that glassmakers of the 16-17th century had full control over the color of the enamel glass paints they made. They mainly used three types of coloring agents, based on Co (dark blue), Mn (purple) and Cu (light-blue or green-blue) as coloring elements. Blue-purple enamel paints were obtained by mixing two different coloring agents. The coloring agent for red-purple enamel, introduced during the 19th century, was colloidal gold embedded in grains of lead glass.

  2. Determination of photocatalytic activity in amorphous and crystalline titanium oxide films prepared using plasma-enhanced chemical vapor deposition

    Science.gov (United States)

    Wu, Cheng-Yang; Chiang, Bo-Sheng; Chang, Springfield; Liu, Day-Shan

    2011-01-01

    Hydro-oxygenated amorphous titanium oxide (a-TiO x:OH) films were prepared by plasma-enhanced chemical vapor deposition (PECVD) using precursors of titanium tetraisopropoxide (TTIP) and oxygen. The influences of chemical states and crystal quality on the photocatalytic activity were systematically investigated in the as-deposited and post-annealed films. The degree of the photocatalytic activity was deeply correlated with the porosity related to the hydroxyl (OH) groups in the as-deposited amorphous film. The crystallized anatase structures was observed from the 200 °C-deposited a-TiO x:OH film after a post-annealing treatment at 400 °C. The photocatalytic activity related to the film with anatase structure was markedly superior to that of an amorphous film with porous structures. The larger the crystal size of the anatase structure, the higher the photocatalytic activity obtained. At elevated annealed temperatures, the inferior anatase structure due to the crystalline transformation led to a low photocatalytic activity. It was concluded that the photocatalytic activity of an amorphous TiO x film prepared using PECVD was determined by the porosity originating from the functional OH groups in the film, whereas the crystalline quality of anatase phase in the annealed poly-TiO x film was crucial to the photocatalytic activity.

  3. Cross-cultural counseling with the chemically dependent: preparing for service delivery within a culture of violence.

    Science.gov (United States)

    Wallace, B C

    1993-01-01

    This article prepares the clinician delivering chemical dependency treatment for more effective work in therapeutic dyads where there are racial, ethnic, or other "differences" between client and therapist. The objective is to prepare clinicians for service delivery within the present culture of violence and for the receipt of additional training in cross-cultural counseling and trauma-resolution psychotherapy. Social learning and unconscious processes are reviewed in order to explain how this culture of violence operates and impacts treatment. The way in which chemically dependent clients of color--especially African-Americans, Native Americans, and Latinos--have been impacted by both personal and cultural trauma is illustrated by a case example. The resolution of clients' personal trauma by properly trained clinicians is presented as relapse prevention and the clients' best defense against becoming a victim of violence and racism. The article ends with a brief description of the recommended clinical technique for this kind of work, and a statement of needed research. PMID:8483053

  4. Cross-cultural counseling with the chemically dependent: preparing for service delivery within a culture of violence.

    Science.gov (United States)

    Wallace, B C

    1993-01-01

    This article prepares the clinician delivering chemical dependency treatment for more effective work in therapeutic dyads where there are racial, ethnic, or other "differences" between client and therapist. The objective is to prepare clinicians for service delivery within the present culture of violence and for the receipt of additional training in cross-cultural counseling and trauma-resolution psychotherapy. Social learning and unconscious processes are reviewed in order to explain how this culture of violence operates and impacts treatment. The way in which chemically dependent clients of color--especially African-Americans, Native Americans, and Latinos--have been impacted by both personal and cultural trauma is illustrated by a case example. The resolution of clients' personal trauma by properly trained clinicians is presented as relapse prevention and the clients' best defense against becoming a victim of violence and racism. The article ends with a brief description of the recommended clinical technique for this kind of work, and a statement of needed research.

  5. Hydroxyapatite, a biomaterial: Its chemical synthesis, characterization and study of biocompatibility prepared from shell of garden snail, Helix aspersa

    Indian Academy of Sciences (India)

    Anjuvan Singh

    2012-11-01

    The shell of garden snail (Helix aspersa) is basically made of calcium carbonate. An attempt is made to convert calcium carbonate of garden snail shell to hydroxyapatite. The snail shell was found to decompose within 850°C to all the carbonate phases. The calcined snail shells were then treated with acids followed by different chemicals in ammoniacal media maintaining proper stoichiometry to produce fine hydroxyapatite (HAP) as filter cake with a Ca/P molar ratio of 1.67. The dried HAP powder was extremely pure with a specific surface area of 15 m2/g. The different characterization techniques were adopted both for calcined snail shell and HAP synthesized by X-ray diffraction (XRD), thermal analysis (DTA/TGA), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The surface area and particle size of HAP powder prepared by chemical precipitation route, were also determined by BET and Malvern particle size analyser, respectively. The synthesized powder was soaked in stimulated body fluid (SBF) medium for various periods of time in order to evaluate its bioactivity. The changes of pH of SBF medium were measured. High bioactivity of prepared HAP powder due to the formation of apatite on its surface was observed.

  6. Preparation of polycrystalline CdS thin films by chemical bath deposition

    Energy Technology Data Exchange (ETDEWEB)

    Lee, E.A.; Kim, B.S.; Shin, S.H.; Park, J.I.; Park, K.J. [National Industrial Technology Inst., Kwacheon (Korea, Republic of). Div. of Inorganic Chemistry

    1996-12-31

    CdS has been recognized as a promising n-type window material for CdTe/CdS and CuInSe{sub 2}/CdS heterojunction thin film solar cells. The authors prepared CdS thin films from a solution containing cadmium acetate, thiourea, ammonia, and ammonium acetate. They varied fabrication conditions such as the concentrations of reactants, reaction temperature, and heat treatment, to investigate the changes in structural and optical properties of the film. Effects of substrate on the properties were also investigated.

  7. Low temperature preparation of nanocrystalline solid solution of strontium barium niobate by chemical process

    Indian Academy of Sciences (India)

    Asit B Panda; Amita Pathak; Panchanan Pramanik

    2002-11-01

    SrBa1–Nb2O6 (with = 0.4, 0.5 and 0.6) powders have been prepared by thermolysis of aqueous precursor solutions consisting of triethanolamine (TEA), niobium tartarate and, EDTA complexes of strontium and barium ions. Complete evaporation of the precursor solution by heating at ∼ 200°C, yields in a fluffy, mesoporous carbon rich precursor material, which on calcination at 750°C/2 h has resulted in the pure SBN powders. The crystallite and average particle sizes are found to be around 15 nm and 20 nm, respectively.

  8. Studies on preparation and characterization of indium doped zinc oxide films by chemical spray deposition

    Indian Academy of Sciences (India)

    Benny Joseph; P K Manoj; V K Vaidyan

    2005-08-01

    The preparation of indium doped zinc oxide films is discussed. Variation of structural, electrical and optical properties of the films with zinc acetate concentration and indium concentration in the solution are investigated. XRD studies have shown a change in preferential orientation from (002) to (101) crystal plane with increase in indium dopant concentration. Films deposited at optimum conditions have a low resistivity of 1.33 × 10-4 m with 94% transmittance at 550 nm. SEM studies have shown smooth polycrystalline morphology of the films. Figure of merit is evaluated from electrical resistivity and transmittance data.

  9. A non-chemically selective top-down approach towards the preparation of hierarchical TS-1 zeolites with improved oxidative desulfurization catalytic performance.

    Science.gov (United States)

    Du, Shuting; Chen, Xiaoxin; Sun, Qiming; Wang, Ning; Jia, Mingjun; Valtchev, Valentin; Yu, Jihong

    2016-02-28

    Hierarchical TS-1 zeolites with secondary macropores have been successfully prepared by using two different fluoride-containing chemical etching post-treated routes. Hierarchical TS-1 zeolites exhibited a chemical composition similar to that of the parent material and showed remarkably enhanced catalytic activity in oxidative desulfurization reaction. PMID:26846586

  10. Preparation of porous bio-char and activated carbon from rice husk by leaching ash and chemical activation.

    Science.gov (United States)

    Ahiduzzaman, Md; Sadrul Islam, A K M

    2016-01-01

    Preparation porous bio-char and activated carbon from rice husk char study has been conducted in this study. Rice husk char contains high amount silica that retards the porousness of bio-char. Porousness of rice husk char could be enhanced by removing the silica from char and applying heat at high temperature. Furthermore, the char is activated by using chemical activation under high temperature. In this study no inert media is used. The study is conducted at low oxygen environment by applying biomass for consuming oxygen inside reactor and double crucible method (one crucible inside another) is applied to prevent intrusion of oxygen into the char. The study results shows that porous carbon is prepared successfully without using any inert media. The adsorption capacity of material increased due to removal of silica and due to the activation with zinc chloride compared to using raw rice husk char. The surface area of porous carbon and activated carbon are found to be 28, 331 and 645 m(2) g(-1) for raw rice husk char, silica removed rice husk char and zinc chloride activated rice husk char, respectively. It is concluded from this study that porous bio-char and activated carbon could be prepared in normal environmental conditions instead of inert media. This study shows a method and possibility of activated carbon from agro-waste, and it could be scaled up for commercial production. PMID:27536531

  11. Preparation of porous bio-char and activated carbon from rice husk by leaching ash and chemical activation.

    Science.gov (United States)

    Ahiduzzaman, Md; Sadrul Islam, A K M

    2016-01-01

    Preparation porous bio-char and activated carbon from rice husk char study has been conducted in this study. Rice husk char contains high amount silica that retards the porousness of bio-char. Porousness of rice husk char could be enhanced by removing the silica from char and applying heat at high temperature. Furthermore, the char is activated by using chemical activation under high temperature. In this study no inert media is used. The study is conducted at low oxygen environment by applying biomass for consuming oxygen inside reactor and double crucible method (one crucible inside another) is applied to prevent intrusion of oxygen into the char. The study results shows that porous carbon is prepared successfully without using any inert media. The adsorption capacity of material increased due to removal of silica and due to the activation with zinc chloride compared to using raw rice husk char. The surface area of porous carbon and activated carbon are found to be 28, 331 and 645 m(2) g(-1) for raw rice husk char, silica removed rice husk char and zinc chloride activated rice husk char, respectively. It is concluded from this study that porous bio-char and activated carbon could be prepared in normal environmental conditions instead of inert media. This study shows a method and possibility of activated carbon from agro-waste, and it could be scaled up for commercial production.

  12. Fe-doped epitaxial YBCO films prepared by chemical solution deposition

    Institute of Scientific and Technical Information of China (English)

    Hong Zhang; Yong Zhao; Wentao Wang; Min Pan; Ming Lei

    2014-01-01

    YBa2Cu3O7-d (YBCO)-coated conductors have wide-ranging potential in large-scale applications such as superconducting maglev trains and superconducting elec-tric cables, but low current carrying capability restrains the practical application of YBCO-coated conductors at high temperatures and high magnetic fields. It is crucial to develop YBCO-coated conductors with high critical cur-rent density. In this paper, epitaxial, dense, smooth, and crack-free Fe-doped YBCO films were prepared on a LaAlO3 single crystal substrate via a fluorine-free polymer-assisted metal organic deposition method. The effects of the dilute Fe doping on microstructure and superconduc-ting character of YBCO films were investigated. The crit-ical temperature for superconducting of the Fe-doped YBCO films decreases slightly. However, the in-field critical current density of YBCO films improves with dilute Fe doping of amounts less than x=0.005, compared to the pure YBCO film. Therefore, the current carrying capability of YBCO film can improve by doping with appropriate amounts of Fe. This means that dilute Fe doping in YBCO films may be a feasible way to prepare high-performance coated conductors.

  13. New crosslinked cast films based on poly(vinyl alcohol: Preparation and physico-chemical properties

    Directory of Open Access Journals (Sweden)

    C. Birck

    2014-12-01

    Full Text Available In this paper, we propose a green route to prepare insoluble poly(vinyl alcohol (PVOH cast films with potential application as antimicrobial packaging. First PVOH films were cast from different aqueous solutions and analyzed by Differential Scanning Calorimetry (DSC and Dynamic Mechanical Analysis (DMA to determine their physical properties under two storage conditions. In order to obtain insoluble films, PVOH was then crosslinked by citric acid (CTR as confirmed by Nuclear Magnetic Resonance (NMR analyses. The crosslinking reaction parameters (curing time, crosslinker content were studied by comparing the characteristics of PVOH/CTR films, such as free COOH content and glass transition temperature (Tg value, as well as the impact of the crosslinking reaction on mechanical properties. It was found that for 40 and 10 wt% CTR contents, 120 and 40 min of crosslinking times were necessary to bind all CTR respectively. Brittle films were obtained for 40 wt% CTR whereas 10 wt% CTR content led to ductile films. Finally, films containing hydroxypropyl-β-cyclodextrin (HPβCD, chosen as a potential vector of antimicrobial agent, were prepared. The obtained results show that the incorporation of HPβCD in the PVOH matrix does not mainly influence the physical and mechanical properties of the films.

  14. Preparation and Chemical Properties of π-Conjugated Polymers Containing Indigo Unit in the Main Chain

    Directory of Open Access Journals (Sweden)

    Hiroki Fukumoto

    2014-03-01

    Full Text Available π-Conjugated polymers based on indigo unit were prepared. Dehalogenative polycondensation of N-hexyl-6,6'-dibromoindigo with a zerovalent nickel complex gave a homopolymer, P(HexI, in 77% yield. Copolymer of N-hexyl-indigo and pyridine, P(HexI-Py, was also prepared in 50% yield. P(HexI showed good solubility in organic solvents, whereas P(HexI-Py was only soluble in acids such as HCOOH. The weight-average molecular weights (Mw of P(HexI and P(HexI-Py were determined to be 10,000 and 40,000, respectively, by a light scattering method. Pd-catalyzed polycondensation between 6,6'-dibromoindigo with N-BOC (BOC = t-butoxycarbonyl substituents and a diboronic compound of 9,9-dioctylfluorene afforded the corresponding alternating copolymer, P(BOCI-Flu, as a deep red solid in 98% yield. P(BOCI-Flu was soluble in N-methyl-2-pyrroridone and showed an Mw of 29,000 in GPC analysis. Treatment of P(BOCI-Flu with CF3COOH smoothly led to a BOC-deprotection reaction to give an insoluble deep green polymer, P(I-Flu, in a quantitative yield. Diffuse reflectance spectra of powdery P(BOCI-Flu and P(I-Flu showed peaks at about 580 nm and 630 nm, respectively, which are thought to originate from the indigo unit.

  15. Chemically prepared La2Se3 nanocubes thin film for supercapacitor application.

    Science.gov (United States)

    Patil, S J; Lokhande, V C; Chodankar, N R; Lokhande, C D

    2016-05-01

    Lanthanum selenide (La2Se3) nanocubes thin film is prepared via successive ionic layer adsorption and reaction (SILAR) method and utilized for energy storage application. The prepared La2Se3 thin film is characterized by X-ray diffraction, field emission scanning electron microscopy and contact angle measurement techniques for structural, surface morphological and wettability studies, respectively. Energy dispersive X-ray microanalysis (EDAX) is performed in order to obtain the elemental composition of the thin film. The La2Se3 film electrode shows a maximum specific capacitance of 363 F g(-1) in a 0.8 M LiClO4/PC electrolyte at a scan rate of 5 mV s(-1) within 1.3 V/SCE potential range. The specific capacitive retention of 83 % of La2Se3 film electrode is obtained over 1000 cyclic voltammetry cycles. The predominant performance, such as high energy (80 Wh kg(-1)) and power density (2.5 kW kg(-1)), indicates that La2Se3 film electrode facilitates fast ion diffusion during redox processes.

  16. Quaternary hard nanocomposite TiCxNy/SiCN coatings prepared by plasma enhanced chemical vapor deposition

    International Nuclear Information System (INIS)

    Individual hard thin film materials such as TiN, SiN1.3, SiC and CNx exhibit attractive mechanical, tribological, optical and electronic properties related to their microstructure and chemical bonding. In the present work, we combine the characteristics of such materials, while systematically studying quaternary thin films prepared by plasma enhanced chemical vapor deposition (PECVD) from TiCl4/SiH4/N2/CH4 mixtures with different concentrations of CH4. Detailed structural and chemical characterizations using transmission electron microscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and elastic recoil detection suggest formation of a TiCxNy/SiCN nanocomposite structure. Depth-sensing indentation, static indentation and curvature measurements, on samples prepared under optimal conditions, reveal a hardness of 55 GPa, reduced Young's modulus of 302 GPa, a compressive stress of 2.0 GPa, an elastic rebound of more than 80 %, H3/Er2 coefficient of 1.8 GPa and a high toughness. The friction coefficient and the wear rate, measured against diamond, are 0.13*10-6 and 12*10-6 mm3/Nm, respectively. We compare the properties of the present nanocomposite TiCxNy/SiCN coatings with the performance of PECVD films from our earlier studies: these include TiN/SiN1.3 nanocomposites and SiCN, for which we obtained a hardness of 45 and 33 GPa, and a reduced Young's modulus of 350 and 200 GPa, respectively

  17. Liposomes for topical use: a physico-chemical comparison of vesicles prepared from egg or soy lecithin.

    Science.gov (United States)

    Budai, Lívia; Kaszás, Nóra; Gróf, Pál; Lenti, Katalin; Maghami, Katayoon; Antal, István; Klebovich, Imre; Petrikovics, Ilona; Budai, Marianna

    2013-12-01

    Developments in nanotechnology and in the formulation of liposomal systems provide the opportunity for cosmetic dermatology to design novel delivery systems. Determination of their physico-chemical parameters has importance when developing a nano-delivery system. The present study highlights some technological aspects/characteristics of liposomes formulated from egg or soy lecithins for topical use. Alterations in the pH, viscosity, surface tension, and microscopic/macroscopic appearance of these vesicular systems were investigated. The chemical composition of the two types of lecithin was checked by mass spectrometry. Caffeine, as a model molecule, was encapsulated into multilamellar vesicles prepared from the two types of lecithin: then zeta potential, membrane fluidity, and encapsulation efficiency were compared. According to our observations, samples prepared from the two lecithins altered the pH in opposite directions: egg lecithin increased it while soy lecithin decreased it with increased lipid concentration. Our EPR spectroscopic results showed that the binding of caffeine did not change the membrane fluidity in the temperature range of possible topical use (measured between 2 and 50 °C). Combining our results on encapsulation efficiency for caffeine (about 30% for both lecithins) with those on membrane fluidity data, we concluded that the interaction of caffeine with the liposomal membrane does not change the rotational motion of the lipid molecules close to the head group region. In conclusion, topical use of egg lecithin for liposomal formulations can be preferred if there are no differences in the physico-chemical properties due to the encapsulated drugs, because the physiological effects of egg lecithin vesicles on skin are significantly better than that of soy lecithin liposomes. PMID:24482779

  18. Evaluation of alternative chemical additives for high-level waste vitrification feed preparation processing

    Energy Technology Data Exchange (ETDEWEB)

    Seymour, R.G.

    1995-06-07

    During the development of the feed processing flowsheet for the Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS), research had shown that use of formic acid (HCOOH) could accomplish several processing objectives with one chemical addition. These objectives included the decomposition of tetraphenylborate, chemical reduction of mercury, production of acceptable rheological properties in the feed slurry, and controlling the oxidation state of the glass melt pool. However, the DEPF research had not shown that some vitrification slurry feeds had a tendency to evolve hydrogen (H{sub 2}) and ammonia (NH{sub 3}) as the result of catalytic decomposition of CHOOH with noble metals (rhodium, ruthenium, palladium) in the feed. Testing conducted at Pacific Northwest Laboratory and later at the Savannah River Technical Center showed that the H{sub 2} and NH{sub 3} could evolve at appreciable rates and quantities. The explosive nature of H{sub 2} and NH{sub 3} (as ammonium nitrate) warranted significant mitigation control and redesign of both facilities. At the time the explosive gas evolution was discovered, the DWPF was already under construction and an immediate hardware fix in tandem with flowsheet changes was necessary. However, the Hanford Waste Vitrification Plant (HWVP) was in the design phase and could afford to take time to investigate flowsheet manipulations that could solve the problem, rather than a hardware fix. Thus, the HWVP began to investigate alternatives to using HCOOH in the vitrification process. This document describes the selection, evaluation criteria, and strategy used to evaluate the performance of the alternative chemical additives to CHOOH. The status of the evaluation is also discussed.

  19. Evaluation of alternative chemical additives for high-level waste vitrification feed preparation processing

    International Nuclear Information System (INIS)

    During the development of the feed processing flowsheet for the Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS), research had shown that use of formic acid (HCOOH) could accomplish several processing objectives with one chemical addition. These objectives included the decomposition of tetraphenylborate, chemical reduction of mercury, production of acceptable rheological properties in the feed slurry, and controlling the oxidation state of the glass melt pool. However, the DEPF research had not shown that some vitrification slurry feeds had a tendency to evolve hydrogen (H2) and ammonia (NH3) as the result of catalytic decomposition of CHOOH with noble metals (rhodium, ruthenium, palladium) in the feed. Testing conducted at Pacific Northwest Laboratory and later at the Savannah River Technical Center showed that the H2 and NH3 could evolve at appreciable rates and quantities. The explosive nature of H2 and NH3 (as ammonium nitrate) warranted significant mitigation control and redesign of both facilities. At the time the explosive gas evolution was discovered, the DWPF was already under construction and an immediate hardware fix in tandem with flowsheet changes was necessary. However, the Hanford Waste Vitrification Plant (HWVP) was in the design phase and could afford to take time to investigate flowsheet manipulations that could solve the problem, rather than a hardware fix. Thus, the HWVP began to investigate alternatives to using HCOOH in the vitrification process. This document describes the selection, evaluation criteria, and strategy used to evaluate the performance of the alternative chemical additives to CHOOH. The status of the evaluation is also discussed

  20. Radio-frequency inductively coupled plasma-chemical installation for preparation of nanodispersed powders

    International Nuclear Information System (INIS)

    Full text: The wide application of radio-frequency inductively coupled plasma (rf-ICP) is due to the following. Rf-ICPs are clean because these types of plasma do not use any electrode and, hence, are contamination free. Rf-ICPs are stable and can be used over a wide range of operating conditions. They have relatively large volumes and low plasma velocities, which result in complete melting of the solid materials in materials processing because of the longer residence time. The preciseness of the rf-ICPs is important in determining contamination effects (which inevitably occur because of electrode evaporation and nozzle ablation) on gas circuit breaker arcs as well as to predict plasma properties for all materials processing, and any gas or mixture of gases can be excited by the rf fields, so there is wide flexibility when choosing plasma gas(es) depending on the type of application [1].; The experimental plasma set-up used for the production of nanosized powders (carbides, carbon nano-structures (nanotubes, fullerenes), oxides, nitrides, catalysts, pigments, etc.) consists of a radio-frequency generator (maximum power 60 kW, frequency 1+30 MHz), a water-cooled quartz plasma-chemical reactor with inductor, raw powder and gas supply systems, a gas quenching device, heat exchangers and cloth filter for powder collection. Ar, N2, Ar+N2, air, air+O2, and Ar+H2 can be used as plasma-forming gases. The quenching gases are air, Ar, N2, and CO2. The raw powder is injected into the upper part of the plasma-chemical reactor. A chemical reaction is carried out in the reactor and after complete evaporation of the micron size powder, it enters the quenching device. After that, the nanosized product is captured by the heat exchangers and cloth filter

  1. Preparation of Dispersed Platinum Nanoparticles on a Carbon Nanostructured Surface Using Supercritical Fluid Chemical Deposition

    Directory of Open Access Journals (Sweden)

    Mineo Hiramatsu

    2010-03-01

    Full Text Available We have developed a method of forming platinum (Pt nanoparticles using a metal organic chemical fluid deposition (MOCFD process employing a supercritical fluid (SCF, and have demonstrated the synthesis of dispersed Pt nanoparticles on the surfaces of carbon nanowalls (CNWs, two-dimensional carbon nanostructures, and carbon nanotubes (CNTs. By using SCF-MOCFD with supercritical carbon dioxide as a solvent of metal-organic compounds, highly dispersed Pt nanoparticles of 2 nm diameter were deposited on the entire surface of CNWs and CNTs. The SCF-MOCFD process proved to be effective for the synthesis of Pt nanoparticles on the entire surface of intricate carbon nanostructures with narrow interspaces.

  2. Antibacterial, Structural and Optical Characterization of Mechano-Chemically Prepared ZnO Nanoparticles.

    Science.gov (United States)

    Manzoor, Umair; Siddique, Sumera; Ahmed, Rafay; Noreen, Zobia; Bokhari, Habib; Ahmad, Iftikhar

    2016-01-01

    Structural investigations, optical properties and antibacterial performance of the pure Zinc Oxide (ZnO) nanoparticles (NPs) synthesized by mechano-chemical method are presented. The morphology, dimensions and crystallinity of the ZnO NPs were controlled by tweaking the mechanical agitation of the mixture and subsequent thermal treatment. ZnO nanoparticles in small (resistant Staphylococcus aureus (MRSA), thus potential for medical applications. Scanning electron microscopy and survival assay indicated that most probably ZnO nanoparticles cause changes in cellular morphology which eventually causes bacterial cell death. PMID:27183165

  3. [Chemical evaluation of morro or jícaro (Crescentia alata) flours prepared by ensilaging and/or dehydration].

    Science.gov (United States)

    Gómez-Brenes, R A; Contreras, I; Braham, J E; Bressani, R

    1980-06-01

    The chemical composition, nutritive value and potential use of the morro fruit (Crescentia alata) has received little attention. The purpose of the present study was: a) to determine appropriate conditions for processing and conservation of the morro fruit without hulls, since a significant part of the production is lost due to inadequate storage conditions, and b) to evaluate, by means of chemical analysis, the whole fruit and its products. For the preparation of dehydrated meals, the content of the fruit was subjected to sun drying and tray drying dehydration with two air temperatures, 60 degrees and 90 degrees C. The method used for the storage of the whole fruit was anaerobic fermentation achieved by ensilaging the fruit in small concrete experimental silos for 90, 145 and 180 days. At the end of each period, the silos were opened. The ensilaged material was of very good appearance and apparently free from unfavorable contaminations; it was dehydrated in tray dryers at an air temperature of 60 degrees C. Independent of processing, the chemical analysis showed the meals to contain on the average 17% crude fat, 11% crude fiber and 18% crude protein. From the amino acid content and using the 1973 FAO/WHO scoring pattern it was found that such flours were limiting in their sulfur amino acid, lysine and threonine content in the order.

  4. The effect of physical and chemical treatment on nano-zeolite characterization and their performance in dimethyl ether preparation

    Directory of Open Access Journals (Sweden)

    Sanaa M. Solyman

    2015-09-01

    Full Text Available Catalytic dehydration of methanol to dimethyl ether (DME was investigated using physically and chemically modified H-Mordenite and H-Beta zeolites as catalysts. Physical modification was carried out using ultrasonic wave’s energy, while chemical modification was performed through impregnation in aluminum nitrate followed by calcination. The produced solid catalysts were evaluated as selective catalysts for the dehydration of methanol to dimethyl ether at 100–250 °C performed at three different contact times. Chemical and structural characterizations of the solid catalysts were identified using XRD, FT-IR, TEM, SEM and NH3-TPD. Ultrasonication physical mixing of solids proved as useful tool of preparation, producing fine reordered crystals of nanocomposite zeolites with novel morphology. The newly ordered crystals were distinguished by their frame work structure, acidic properties, crystal and particle sizes, unit cell volume, pore opening, and favorable catalytic activity of 100% selectivity to DME at 200 °C for all contact times studied. The effects of Al2O3 on the dispersion and interaction within the nano-zeolite crystals and hence on the catalytic dehydration of methanol were verified as the major influence toward utmost selectivity.

  5. NOVEL PREPARATION AND MAGNETO CHEMICAL CHARACTERIZATION OF NANO-PARTICLE MIXED ALCOHOL CATALYSTS

    Energy Technology Data Exchange (ETDEWEB)

    Setala V. Naidu

    2003-01-01

    We have produced Co, Cu, and Fe nano-particles by Laser-induced solution deposition (LISD) as evidenced by TEM investigations. Sizes of the nano-particles created are in the order of 5 nm. The LISD system could generate nano-particles in quantities only in the order of a milligram. This may be mainly due to the limited photo induced reactions taking place on the surface of the solutions. We have designed experiments to use drop flow technique with LISD for nano-particle deposition on microreactors. Preliminary work has been done on Co and Fe thin film deposited microreactors. We are also investigating the catalytic properties of nano-particles of FeO and CoO prepared by ball milling and dispersed into sol-gel prepared alumina granules. We have continued our investigation of catalytic reactions of Cu, Co, Fe, Cu/Co, Cu/Fe and Co/Fe on alumina support. The metal oxides were first reduced with hydrogen and used for the conversion of CO/H{sub 2}. The surface area of the catalysts has been determined by nitrogen disorption. They are in the range of 200-300 m{sup 2}/g. Cu, Co, Fe, Co/Fe, Cu/Co and Cu/Fe showed increasing order of catalytic activity for CO/H{sub 2} conversion. We are also studying catalytic conversion rates for CO{sub 2}/H{sub 2} and CO/CO{sub 2}/H{sub 2} mixtures using these catalysts. Our investigations of Co and Fe thin film deposited microreactors showed higher CO/H{sub 2} conversion for Fe compared to Co. We have used vibrating sample magnetometer (VSM) to study the magnetic characteristics of as prepared, reduced, post-reaction catalysts. Comparative study of the ferromagnetic component of these samples gives the reduction efficiency and the changes in metal centers during catalytic reactions. Magnetic studies of post-reaction Co and Fe micro-reactors show that more carbide formation occurs for iron compared to cobalt.

  6. Transparent conducting oxide films of group V doped titania prepared by aqueous chemical solution deposition

    Energy Technology Data Exchange (ETDEWEB)

    Elen, Ken [Inorganic and Physical Chemistry, Institute for Materials Research, Hasselt University, Agoralaan Building D, B-3590 Diepenbeek (Belgium); IMEC vzw division IMOMEC, Agoralaan Building D, B-3590 Diepenbeek (Belgium); Strategisch Initiatief Materialen (SIM), SoPPoM Program (Belgium); Capon, Boris [Strategisch Initiatief Materialen (SIM), SoPPoM Programm (Belgium); Coating and Contacting of Nanostructures, Ghent University, Krijgslaan 281 S1, B-9000 Ghent (Belgium); De Dobbelaere, Christopher [Inorganic and Physical Chemistry, Institute for Materials Research, Hasselt University, Agoralaan Building D, B-3590 Diepenbeek (Belgium); Dewulf, Daan [Inorganic and Physical Chemistry, Institute for Materials Research, Hasselt University, Agoralaan Building D, B-3590 Diepenbeek (Belgium); IMEC vzw division IMOMEC, Agoralaan Building D, B-3590 Diepenbeek (Belgium); Peys, Nick [Inorganic and Physical Chemistry, Institute for Materials Research, Hasselt University, Agoralaan Building D, B-3590 Diepenbeek (Belgium); IMEC vzw, Kapeldreef 75, B-3001 Heverlee (Belgium); Detavernier, Christophe [Coating and Contacting of Nanostructures, Ghent University, Krijgslaan 281 S1, B-9000 Ghent (Belgium); Hardy, An [Inorganic and Physical Chemistry, Institute for Materials Research, Hasselt University, Agoralaan Building D, B-3590 Diepenbeek (Belgium); IMEC vzw division IMOMEC, Agoralaan Building D, B-3590 Diepenbeek (Belgium); Van Bael, Marlies K., E-mail: marlies.vanbael@uhasselt.be [Inorganic and Physical Chemistry, Institute for Materials Research, Hasselt University, Agoralaan Building D, B-3590 Diepenbeek (Belgium); IMEC vzw division IMOMEC, Agoralaan Building D, B-3590 Diepenbeek (Belgium)

    2014-03-31

    Transparent conducting oxide (TCO) films of titania doped with vanadium (V), niobium (Nb) and tantalum (Ta) are obtained by aqueous Chemical Solution Deposition (CSD). The effect of the dopant on the crystallization and microstructure of the resulting films is examined by means of X-ray diffraction and electron microscopy. During annealing of the thin films, in-situ characterization of the crystal structure and sheet resistance is carried out. Niobium doped anatase films, obtained after annealing in forming gas, show a resistivity of 0,28 Ohm cm, which is the lowest resistivity reported for a solution deposited anatase-based TCO so far. Here, we demonstrate that aqueous CSD may provide a strategy for scalable TCO production in the future. - Highlights: • Aqueous chemical solution deposition of doped titanium dioxide • Doping delays the phase transition from anatase to rutile • Lowest resistivity after doping with niobium and annealing in Forming Gas • Transparency higher than 80% in the visible range of optical spectrum.

  7. Cytotoxicity of Boron-Doped Nanocrystalline Diamond Films Prepared by Microwave Plasma Chemical Vapor Deposition

    Science.gov (United States)

    Liu, Dan; Gou, Li; Ran, Junguo; Zhu, Hong; Zhang, Xiang

    2015-07-01

    Boron-doped nanocrystalline diamond (NCD) exhibits extraordinary mechanical properties and chemical stability, making it highly suitable for biomedical applications. For implant materials, the impact of boron-doped NCD films on the character of cell growth (i.e., adhesion, proliferation) is very important. Boron-doped NCD films with resistivity of 10-2 Ω·cm were grown on Si substrates by the microwave plasma chemical vapor deposition (MPCVD) process with H2 bubbled B2O3. The crystal structure, diamond character, surface morphology, and surface roughness of the boron-doped NCD films were analyzed using different characterization methods, such as X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM) and atomic force microscopy (AFM). The contact potential difference and possible boron distribution within the film were studied with a scanning kelvin force microscope (SKFM). The cytotoxicity of films was studied by in vitro tests, including fluorescence microscopy, SEM and MTT assay. Results indicated that the surface roughness value of NCD films was 56.6 nm and boron was probably accumulated at the boundaries between diamond agglomerates. MG-63 cells adhered well and exhibited a significant growth on the surface of films, suggesting that the boron-doped NCD films were non-toxic to cells. supported by the Open Foundation of State Key Laboratory of Electronic Thin Films and Integrated Devices (University of Electronic Science and Technology of China) (No. KFJJ201313)

  8. Transparent conducting oxide films of group V doped titania prepared by aqueous chemical solution deposition

    International Nuclear Information System (INIS)

    Transparent conducting oxide (TCO) films of titania doped with vanadium (V), niobium (Nb) and tantalum (Ta) are obtained by aqueous Chemical Solution Deposition (CSD). The effect of the dopant on the crystallization and microstructure of the resulting films is examined by means of X-ray diffraction and electron microscopy. During annealing of the thin films, in-situ characterization of the crystal structure and sheet resistance is carried out. Niobium doped anatase films, obtained after annealing in forming gas, show a resistivity of 0,28 Ohm cm, which is the lowest resistivity reported for a solution deposited anatase-based TCO so far. Here, we demonstrate that aqueous CSD may provide a strategy for scalable TCO production in the future. - Highlights: • Aqueous chemical solution deposition of doped titanium dioxide • Doping delays the phase transition from anatase to rutile • Lowest resistivity after doping with niobium and annealing in Forming Gas • Transparency higher than 80% in the visible range of optical spectrum

  9. Physico-chemical characteristics of nano-organo bentonite prepared using different organo-modifiers

    Directory of Open Access Journals (Sweden)

    A.M. Motawie

    2014-09-01

    Full Text Available Different types of nano-organo bentonite (NOB were prepared from the Egyptian Bentonite (EB. EB was characterized by energy dispersive X-ray EDX. It was purified from different impurities using a conventional method via the treatment with HCl and distilled water. The modification of the clay was carried out using different types of organo-modifiers namely; hexadecyl trimethyl ammonium bromide (HTAB, 3-aminopropyltriethoxysilane (Silane, octadecylamine (ODA, and dodecylamine (DDA. The cation exchange capacity (CEC was measured for pristine bentonite after and before modification. The NB was characterized by FTIR, XRD, TEM, and TGA techniques. The obtained results indicated that variation of the interlayer space gallery was effected by the type of the penetrator used.

  10. Preparation and Performance of an Adsorption Type Gel Plugging Agent as Enhanced Oil Recovery Chemical

    Directory of Open Access Journals (Sweden)

    Xiaoping Qin

    2015-01-01

    Full Text Available A novel adsorption type gel plugging agent (ATGPA was prepared using acrylamide (AM, acrylic acid (AA, diallyl dimethyl ammonium chloride (DMDAAC, 2-acrylamido-2-methylpropanesulfonate (AMPS, formaldehyde (HCHO, resorcinol (C6H6O2, and thiocarbamide (CH4N2S as raw materials under mild conditions. ATGPA was characterized by infrared (IR spectroscopy, elemental analysis, and scanning electron microscope (SEM. It was found that ATGPA exhibited higher elastic modulus (G′ and viscous modulus (G′′ than AM/AA gel plugging agent (AAGPA under the same scanning frequency. It was also found that ATGPA had moderate temperature resistance and salt tolerance. Core plugging tests results indicated that ATGPA could achieve up to higher plugging rate (PR than AAGPA (97.2% versus 95.7% at 65°C. In addition, ATGPA possessed stronger antiscouring ability by core plugging experiments at 65°C.

  11. Fabrication and Photovoltaic Characteristics of Coaxial Silicon Nanowire Solar Cells Prepared by Wet Chemical Etching

    Directory of Open Access Journals (Sweden)

    Chien-Wei Liu

    2012-01-01

    Full Text Available Nanostructured solar cells with coaxial p-n junction structures have strong potential to enhance the performances of the silicon-based solar cells. This study demonstrates a radial junction silicon nanowire (RJSNW solar cell that was fabricated simply and at low cost using wet chemical etching. Experimental results reveal that the reflectance of the silicon nanowires (SNWs declines as their length increases. The excellent light trapping was mainly associated with high aspect ratio of the SNW arrays. A conversion efficiency of ∼7.1% and an external quantum efficiency of ∼64.6% at 700 nm were demonstrated. Control of etching time and diffusion conditions holds great promise for the development of future RJSNW solar cells. Improving the electrode/RJSNW contact will promote the collection of carries in coaxial core-shell SNW array solar cells.

  12. Effect of indium doping on zinc oxide films prepared by chemical spray pyrolysis technique

    Indian Academy of Sciences (India)

    Girjesh Singh; S B Shrivastava; Deepti Jain; Swati Pandya; T Shripathi; V Ganesan

    2010-10-01

    We report the conducting and transparent In doped ZnO films fabricated by a homemade chemical spray pyrolysis system (CSPT). The effect of In concentration on the structural, morphological, electrical and optical properties have been studied. These films are found to show (0 0 2) preferential growth at low indium concentrations. An increase in In concentration causes a decrease in crystalline quality of films as confirmed by X-ray diffraction technique which leads to the introduction of defects in ZnO. Indium doping also significantly increased the electron concentrations, making the films heavily type. However, the crystallinity and surface roughness of the films decreases with increase in indium doping content likely as a result of the formation of smaller grain size, which is clearly displayed in AFM images. Typical optical transmittance values in the order of (80%) were obtained for all films. The lowest resistivity value of 0.045 -m was obtained for film with 5% indium doping.

  13. Deposition and characterization of Ru thin films prepared by metallorganic chemical vapor deposition

    CERN Document Server

    Kang, S Y; Lee, S K; Hwang, C S; Kim, H J

    2000-01-01

    Ru thin films were deposited at 300 approx 400 .deg. C by using Ru(C sub 5 H sub 4 C sub 2 H sub 5) sub 2 (Ru(EtCp) sub 2) as a precursor and low-pressure metalorganic chemical vapor deposition. The addition of O sub 2 gas was essential to form Ru thin films. The deposition rates of the films were about 200 A/min. For low oxygen addition and high substrate temperature, RuO sub 2 phases were formed. Also, thermodynamic calculations showed that all the supplied oxygen was consumed to oxidize carbon and hydrogen, cracked from the precursor ligand, rather than Ru. Thus, metal films could be obtained There was an optimum oxygen to precursor ratio at which the pure Ru phase could be obtained with minimum generation of carbon and RuO sub 2

  14. Chemical, microbiological and sensory evaluation of mayonnaise prepared from ostrich eggs

    Directory of Open Access Journals (Sweden)

    Abou-Arab, Azza A.

    2008-12-01

    Full Text Available Ostrich eggs were evaluated for their chemical composition and mineral contents. Also, chemical, microbiological and sensory evaluation of the mayonnaise made from ostrich eggs in comparison to that made from chicken eggs were studied. Data indicated that ostrich eggs are a good source of protein (47.09 %, total lipids (45.10 %, carbohydrates (4.03 %, calcium (206.5 mg/100g, phosphorus (683.8 mg/100g, potassium (460 mg/100g, sodium (408.7 mg/100g and zinc (5.2 mg/100g. The chemical evaluation of unpasteurized and pasteurized mayonnaise indicated that mayonnaise made from ostrich eggs was more resistant to chemical spoilage due to auto-oxidation than that made from chicken eggs. In ostrich egg mayonnaise, stored unpasteurized was associated with significantly (P En este trabajo se ha evaluado la composición química y el contenido mineral de los huevos de avestruz. Asimismo se ha realizado la evaluación química, microbiológica y sensorial de la mayonesa preparada con huevos de avestruz en comparación con la preparada con huevos de gallina. Los resultados han mostrado que los huevos de avestruz son una buena fuente de proteínas (47,09 %, lípidos totales (45,10 %, carbohidratos (4,03 %, calcio (206,5 mg/100g, fósforo (683,8 mg/100g, potasio (460 mg/100g, sodio (408,7 mg/100g y zinc (5,2 mg/100g. La evaluación química de la mayonesa pasteurizada y no pasteurizada indicó que la mayonesa preparada con huevos de avestruz era más resistente al deterioro químico debido a autoxidación que la preparada con huevos de gallina. La mayonesa de huevos de avestruz almacenada sin pasteurizar fue asociada con una acidez valorable significativamente mayor (P < 0,05. Por el contrario, la acidez valorable no se alteró en las muestras pasteurizadas. Sin embargo, en la mayonesa de huevos de gallina la acidez valorable no varió ni en las muestras pasteurizadas ni en las no pasteurizadas. El grado de acidez y el valor del ácido tiobarbitúrico de las

  15. Biological functionalization and patterning of porous silicon prepared by Pt-assisted chemical etching

    International Nuclear Information System (INIS)

    Porous silicon fabricated via Pt-assisted chemical etching of p-type Si (1 0 0) in 1:1:1 EtOH/HF/H2O2 solution possesses a longer durability in air and in aqueous media than anodized one, which is advantageous for biomedical applications. Its surface SiHx (x = 1 and 2) species can react with 10-undecylenic acid completely under microwave irradiation, and subsequent derivatizations of the end carboxylic acid result in affinity capture of proteins. We applied two approaches to produce protein microarrays: photolithography and spotting. The former provides a homogeneous microarray with a very low fluorescence background, while the latter presents an inhomogeneous microarray with a high noise background.

  16. Preparation and properties of nano-composite ceramic coating by thermo chemical reaction method

    Institute of Scientific and Technical Information of China (English)

    MA Zhuang; SUN Fang-hong; LI Zhi-chao

    2007-01-01

    Nano-composite ceramic coating was fabricated on Q235 steel through thermo chemical reaction method. Structure of the coating was analyzed and the properties were tested. The results show that a few of new ceramic phases, such as MgAl2O4, ZnAl2O4,Al2SiO5, Ni3Fe and Fe3Al, are formed on the coating during the process of solidifying at 600 ℃. The ceramic coating is dense and the high bonding strength is obtained. The average bonding strength between the coating and matrix could be 14.22 MPa. The acid resistance of the coating increase by 8.8 times, the alkali resistance by 4.1 times, the salt resistance by 10.3 times, and the wear resistance by 2.39 times.

  17. Formation and chemical reactivity of carbon fibers prepared by defluorination of graphite fluoride

    Science.gov (United States)

    Hung, Ching-Cheh

    1994-01-01

    Defluorination of graphite fluoride (CFX) by heating to temperatures of 250 to 450 C in chemically reactive environments was studied. This is a new and possibly inexpensive process to produce new carbon-based materials. For example, CF 0.68 fibers, made from P-100 carbon fibers, can be defluorinated in BrH2C-CH = CH-CH2Br (1,4-dibromo-2butene) heated to 370 C, and graphitized to produce fibers with an unusually high modulus and a graphite layer structure that is healed and cross-linked. Conversely, a sulfur-doped, visibly soft carbon fiber was produced by defluorinating CF 0.9 fibers, made from P-25, in sulfur (S) vapor at 370 C and then heating to 660 C in nitrogen (N2). Furthermore, defluorination of the CF 0.68 fibers in bromine (Br2) produced fragile, structurally damaged carbon fibers. Heating these fragile fibers to 1100 C in N2 caused further structural damage, whereas heating to 150 C in bromoform (CHBr3) and then to 1100 C in N2 healed the structural defects. The defluorination product of CFX, tentatively called activated graphite, has the composition and molecular structure of graphite, but is chemically more reactive. Activated graphite is a scavenger of manganese (Mn), and can be intercalated with magnesium (Mg). Also, it can easily collect large amounts of an alloy made from copper (Cu) and type 304 stainless steel to form a composite. Finally, there are indications that activated graphite can wet metals or ceramics, thereby forming stronger composites with them than the pristine carbon fibers can form.

  18. Study of Chemical Treatment Combined with Radiation to Prepare Biotic Elicitor for Utilization in Agriculture

    International Nuclear Information System (INIS)

    Chitosan was prepared from shrimp shell (alpha chitosan) and from squid pen (beta chitosan) with degree of deacetylation of about 70%. Degradation of chitosan in flake form by combined treatment with H2O2 and gamma Co-60 radiation was carried out. Results showed that combined treatment was highly effective for degradation of chitosan to obtain low molecular weight of 1-2 × 105. Oligochitosan was prepared by irradiation of chitosan solution of 50g/l (5%, w/v). The dose required for oligochitosan with water soluble content of more than 70% was of 32kGy and 48kGy for beta and alpha chitosan, respectively. Synergic effect of degradation of chitosan in solution with H2O2 and gamma Co-60 radiation was also investigated. The dose to obtain oligochitosan was reduced from 32kGy to 4kGy for beta chitosan and from 48kGy to 8kGy for alpha chitosan. The elicitation and growth promotion effect of oligochiotsan for sugarcane and rice were investigated. Results showed that oligochitosan with water soluble content of 70-80% (Mw~5,000-10,000) exhibited the most effective elicitation and growth promotion for plant. The optimum oligochitosan concentration by spraying was of 30 and 15ppm for sugarcane and rice, respectively. The disease index of Ustilgo scitaminea and Collectotrichum falcatum on sugarcane were reduced to 44.5 and 72.3% compared to control (100%). The productivity of sugarcane was increased about 13% (8tons/ha). The disease index of Pyricularia grisea on rice was reduced to 53.0% for leaf and 34.1% for neck of bloom compared to control (100%). The productivity of rice was increased for 11-26% (0.6-1.4 tons/ha). The obtained results indicated that oligochitosan is promising to use as a biotic elicitor for plant particularly for sugarcane and rice. The procedure for production of oligochitosan elicitor by γ- irradiation method was described. (author)

  19. Effect of Preparation Conditions on the Crystallinity of Chemically Synthesized BCNO Nanophosphor

    Institute of Scientific and Technical Information of China (English)

    Lakhwant Singh; Viblla Chopra

    2011-01-01

    The carbon based boron oxynitride (BCNO) phosphor was synthesized by solid state reaction between boric acid (H3BO3) and melamine (C3H6N6) in the molar ratios of 1:1 and 2:1 respectively at different temperatures up to 1400℃. The composition with molar ratios 1:1 of starting materials is found to be highly crystalline with an average particle size of 38 nm and the lattice constants a=b=0.251 nm and c=0.666 nm. The solid state reaction of boric acid and melamine in the composition 2:1 leads to the formation of compound in the semi-crystalline state under the same conditions of preparation, but its phase cannot be recognised. The X-ray diffraction (XRD) spectra, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) images of BCNO compound confirm the phase, nanometre size and shape respectively of synthesized material. The photoluminescence (PL) spectra of the synthesized BCNO products reveals that the electronic structure of BCNO compound can be controlled by changing the molar ratios of starting materials and heating temperatures. These synthesized compounds are very interesting and important candidate materials for light emitter.

  20. Physico-chemical, optical and electrochemical properties of iron oxide thin films prepared by spray pyrolysis

    International Nuclear Information System (INIS)

    Iron oxide thin films were prepared by spray pyrolysis technique onto glass substrates from iron chloride solution. They were characterized by X-ray diffractometry (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and (UV-vis) spectroscopy. The films deposited at T s ≤ 450 deg. C were amorphous; while those produced at T sub = 500 deg. C were polycrystalline α-Fe2O3 with a preferential orientation along the (1 0 4) direction. By observing scanning electron microscopy (SEM), it was seen that iron oxide films were relatively homogeneous uniform and had a good adherence to the glass substrates. The grain size was found (by RX) between 19 and 25 nm. The composition of these films was examined by X-ray photoelectron spectroscopy and electron probe microanalysis (EPMA). These films exhibited also a transmittance value about 80% in the visible and infrared range. The cyclic voltammetry study showed that the films of Fe2O3 deposited on ITO pre-coated glass substrates were capable of charge insertion/extraction when immersed in an electrolyte of propylene carbonate (PC) with 0.5 M LiCLO4

  1. Chemical modification of cellulose extracted from sugarcane bagasse: Preparation of hydroxyethyl cellulose

    Directory of Open Access Journals (Sweden)

    E.S. Abdel-Halim

    2014-07-01

    Full Text Available Cellulose was extracted from sugarcane bagasse by alkaline extraction with sodium hydroxide followed by delignification/bleaching using sodium chlorite/hexamethylenetetramine system. Factors affecting extraction process, including sodium hydroxide concentration, hexamethylenetetramine concentration and temperature were studied and optimum conditions for alkaline extraction were found to be boiling finely ground bagasse under reflux in 1 N sodium hydroxide solution and then carrying out the delignification/bleaching treatment at 95 °C using 5 g/l sodium chlorite together with 0.02 g/l hexamethylenetetramine. The extracted cellulose was used in the preparation of hydroxyethyl cellulose through reaction with ethylene oxide in alkaline medium. Factors affecting the hydroxyethylation reaction, like sodium hydroxide concentration during the alkali formation step, ethylene oxide concentration, reaction temperature and reaction duration were studied. Optimum conditions for hydroxyethylation reaction were using 20% NaOH solution and 200% ethylene oxide (based on weight of cellulose, carrying out the reaction at 100 °C for 60 min.

  2. Chitosan-lignosulfonates sono-chemically prepared nanoparticles: characterisation and potential applications.

    Science.gov (United States)

    Kim, Suyeon; Fernandes, Margarida M; Matamá, Teresa; Loureiro, Ana; Gomes, Andreia C; Cavaco-Paulo, Artur

    2013-03-01

    Due to their recognised properties of biocompatibility, biodegradability and sustainability, chitosan nanocarriers have been successfully used as new delivery systems. In this work, nanoparticles combining chitosan and lignosulfonates were developed for the first time for cosmetic and biomedical applications. The ability of lignosulfonates to act as a counter polyion for stabilisation of chitosan particles, generated using high intensity ultrasound, was investigated. Several conditions for particles preparation were tested and optimised and the resulting nanoparticles were comprehensively characterised by measuring particle size, zeta potential and polydispersity index. The pH of chitosan solution, sonication time and the presence of an adequate surfactant, poloxamer 407, were determinant factors on the development of smaller particles with low polydispersity index (an average particle size of 230 nm was obtained at pH 5 after 8 min of sonication). The beneficial effects of lignosulfonates complex on chitosan nanoparticles were further characterised. Greater stability to lysozyme degradation, biocompatibility with human cells and antimicrobial activity was found upon lignosulfonates incorporation into chitosan nanoparticles. Furthermore, these particles were able to incorporate a hydrophilic model protein - RNase A. A burst release was observed when nanoparticles were loaded with low amount of protein while with high protein content, a sustained release was found, suggesting that the protein cargo maybe loaded both at the surface as in the bulk of the particle, depending on the concentration of drug incorporated.

  3. Preparation and Performance of Rare Earths Chemical Conversion Film on Magnesium Alloy

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Golden yellow cerium conversion film was obtained on magnesium alloys surface by immersion method and the preparation parameters were established. The influence of different process parameters on the surface morphology and performance of the conversion film were analyzed by means of SEM and electrochemical method. Formation dynamics about cerium conversion film on magnesium alloy in solution containing cerium salt and the anti-corrosion behavior of the conversion film in 3.5% NaCl solution were studied by electrochemical method respectively. The results shows that the conversion film is more compact at room temperature when concentration of cerium sulfate is 10 g·L-1 in the solution; the open circuit potential of the magnesium sample moves up to positive direction about 100 mV, the surface of conversion film becomes even and lustrous, and the adhesion intensity of conversion film increases when adding aluminum nitrate into the solution containing cerium salt. The pH value of the solution and immersion time of the sample in the solution also affect the surface morphology and anti-corrosion property of the conversion film. After covered by rare earths conversion film, the anti-corrosion property of magnesium alloy is obviously improved. Rare earth conversion film has self-repairing capability in corrosion medium.

  4. Kondo effect in Co{sub x}Cu{sub 1-x} granular alloys prepared by chemical reduction method

    Energy Technology Data Exchange (ETDEWEB)

    Dhara, Susmita, E-mail: susmita.dhara@saha.ac.in; Chowdhury, Rajeswari Roy; Bandyopadhyay, Bilwadal [CMP Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata-700064 (India)

    2015-06-24

    Nanostructured CoCu granular alloys Co{sub x}Cu{sub 1-x} (x ≤ 0.3) have been prepared by chemical reduction method using NaBH{sub 4} as a reducing agent. Electronic transport properties are studied in the temperature range 4-300 K. Resistance exhibits a metallic behavior below room temperature and draws a minimum near 20 K in all the samples except in Co{sub 0.3}Cu{sub 0.7}. This low temperature resistivity minimum diminishes with applied magnetic field. There is also a logarithmic temperature dependence of resistivity at temperatures below 20 K. This phenomenon indicates a Kondo-like scattering mechanism involving magnetic Co impurity spin clusters in Cu host.

  5. Synthesis and Magnetic Properties of Nanoparticles of Fe-Co Alloys and Their Oxides Prepared by Chemical Vapor Condensation

    Institute of Scientific and Technical Information of China (English)

    Zhenhua WANG; Zhidong ZHANG; C.J. Choi; B.K. Kim; J.C. Kim

    2004-01-01

    Nanoparticles of Fe-Co alloys and their oxides with the particle size below 20 nm were prepared by chemical vapor condensation process. The pure Ar, Ar+1%O2, Ar+3%O2 and Ar+6%O2 were used as carrier gases, with iron carbonyl and cobalt carbonyl as the precursors. XRD patterns showed that Fe-Co metallic nanoparticles were synthesized by using pure Ar as carrier gas,and only metal oxides were obtained using Ar+(>3)%O2 as carrier gas. The HRTEM images and TG-DTA curves were used to study the core-shell structure of the different nanoparticles. The nanoparticles obtained in pure Ar consist of black core and light shell with thickness of 2~4 nm. However, in the particles obtained in Ar+6%O2, the oxides core with visible lattice fringes are surrounded by thin shell.

  6. TEXTURAL AND CHEMICAL CHARACTERISATION OF ACTIVATED CARBONS PREPARED FROM RICE HUSK (ORYZA SATIVA USING A TWO- STAGE ACTIVATION PROCESS

    Directory of Open Access Journals (Sweden)

    JOSEPH G. COLLIN

    2008-12-01

    Full Text Available Activated carbons from agro-industrial wastes; rice husk; were prepared by physical and chemical activation using phosphoric acid as the dehydrating agent. A two-stage activation process method was used; with semi-carbonisation stage at 200oC for 15 minutes as the first stage followed by an activation stage at 500oC for 45 minutes as the second stage. The precursor material with the impregnation agent was exposed straightaway to semi-carbonization and activation temperature unlike the specific temperature progression as reported in the literature. All experiments were conducted in a laboratory scale muffle furnace under static conditions in a self generated atmosphere covering process parameters such as impregnation ratios. We found that by using this method, the AC5 had the highest iodine number and methylene blue adsorption capacity which was 506.6 mg/g and 319.0 mg/g respectively.

  7. Passivated graphene transistors fabricated on a millimeter-sized single-crystal graphene film prepared with chemical vapor deposition

    International Nuclear Information System (INIS)

    In this work, we first investigate the effects of partial pressures and flow rates of precursors on the single-crystal graphene growth using chemical vapor depositions on copper foils. These factors are shown to be critical to the growth rate, seeding density and size of graphene single crystals. The prepared graphene films in millimeter sizes are then bubbling transferred to silicon-dioxide/silicon substrates for high-mobility graphene transistor fabrications. After high-temperature annealing and hexamethyldisilazane passivation, the water attachment is removed from the graphene channel. The elimination of uncontrolled doping and enhancement of carrier mobility accompanied by these procedures indicate that they are promising for fabrications of graphene transistors. (paper)

  8. Passivated graphene transistors fabricated on a millimeter-sized single-crystal graphene film prepared with chemical vapor deposition

    Science.gov (United States)

    Lin, Meng-Yu; Wang, Cheng-Hung; Chang, Shu-Wei; Lee, Si-Chen; Lin, Shih-Yen

    2015-07-01

    In this work, we first investigate the effects of partial pressures and flow rates of precursors on the single-crystal graphene growth using chemical vapor depositions on copper foils. These factors are shown to be critical to the growth rate, seeding density and size of graphene single crystals. The prepared graphene films in millimeter sizes are then bubbling transferred to silicon-dioxide/silicon substrates for high-mobility graphene transistor fabrications. After high-temperature annealing and hexamethyldisilazane passivation, the water attachment is removed from the graphene channel. The elimination of uncontrolled doping and enhancement of carrier mobility accompanied by these procedures indicate that they are promising for fabrications of graphene transistors.

  9. (001) Oriented piezoelectric films prepared by chemical solution deposition on Ni foils

    Energy Technology Data Exchange (ETDEWEB)

    Yeo, Hong Goo, E-mail: hxy162@psu.edu; Trolier-McKinstry, Susan [Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States)

    2014-07-07

    Flexible metal foil substrates are useful in some microelectromechanical systems applications including wearable piezoelectric sensors or energy harvesters based on Pb(Zr,Ti)O₃ (PZT) thin films. Full utilization of the potential of piezoelectrics on metal foils requires control of the film crystallographic texture. In this study, (001) oriented PZT thin films were grown by chemical solution deposition (CSD) on Ni foil and Si substrates. Ni foils were passivated using HfO₂ grown by atomic layer deposition in order to suppress substrate oxidation during subsequent thermal treatment. To obtain the desired orientation of PZT film, strongly (100) oriented LaNiO₃ films were integrated by CSD on the HfO₂ coated substrates. A high level of (001) LaNiO₃ and PZT film orientation were confirmed by X-ray diffraction patterns. Before poling, the low field dielectric permittivity and loss tangents of (001) oriented PZT films on Ni are near 780 and 0.04 at 1 kHz; the permittivity drops significantly on poling due to in-plane to out-of-plane domain switching. (001) oriented PZT film on Ni displayed a well-saturated hysteresis loop with a large remanent polarization ~36 μC/cm², while (100) oriented PZT on Si showed slanted P-E hysteresis loops with much lower remanent polarizations. The |e{sub 31,f}| piezoelectric coefficient was around 10.6 C/m² for hot-poled (001) oriented PZT film on Ni.

  10. Preparation of polyethylene sacks for collection of precipitation samples for chemical analysis

    Science.gov (United States)

    Schroder, L.J.; Bricker, A.W.

    1985-01-01

    Polyethylene sacks are used to collect precipitation samples. Washing polyethylene with acetone, hexane, methanol, or nitric acid can change the adsorptive characteristics of the polyethylene. In this study, simulated precipitation at pH 4.5 was in contact with the polyethylene sacks for 21 days; subsamples were removed for chemical analysis at 7, 14, and 21 days after intitial contact. Sacks washed with acetone adsorbed iron and lithium; sacks washed with hexane adsorbed barium, iron , and lithium; sacks washed with methanol adsorbed calcium and iron; and sacks washed with 0.30 N nitric acid adsorbed iron. Leaching the plastic sacks with 0.15 N nitric acid did not result in 100-percent recovery of any of the adsorbed metals. Washing polyethylene sacks with dilute nitric acid caused the pH of the simulated precipitation to be decreased by 0.2 pH unit after 1 week of contact with the polyethylene. The specific conductance increased by 10 microsiemens per centimeter. Contamination of precipitation samples by lead was determined to be about 0.1 microgram per liter from contact with precleaned polyethylene sacks. No measurable contamination of precipitation samples by zinc occurred. (USGS)

  11. Plasmon-mediated photocatalytic activity of wet-chemically prepared ZnO nanowire arrays.

    Science.gov (United States)

    Dao, Thang Duy; Han, Gui; Arai, Nono; Nabatame, Toshihide; Wada, Yoshiki; Hoang, Chung Vu; Aono, Masakazu; Nagao, Tadaaki

    2015-03-21

    We report on measurements and simulations of the efficient sunlight-driven and visible-active photocatalysts composed of plasmonic metal nanoparticles and ZnO nanowire (NW) arrays fabricated via an all-wet-chemical route. Because of the coupling between the ZnO dielectric response and the excitation of the Ag or Au nanoparticles, efficient electronic excitation can be induced in the vicinity of the metal-ZnO interfaces because optically-excited plasmonic particles can not only concentrate the electromagnetic field at the ZnO/particle interface, but also act as efficient sources of plasmonic hot electrons to be injected into the conduction band of the ZnO catalyst. The catalytic activities of the fabricated ZnO NWs are examined by photodegradation of methylene blue and by photocurrent measurements in a photovoltaic configuration. Numerical electromagnetic simulations were used to understand the behavior of the light on the nanometer-scale to clarify the catalytic enhancement mechanisms in both the ultraviolet (UV) and visible (VIS) regions. In addition, simulation results indicated that a near-surface normal but slightly tilted ZnO NW array geometry would provide an increased optical path length and enhanced multiple scattering and absorption processes arising from the localized surface plasmon resonances of the nanoparticles. The results obtained here clarify the role of the plasmon resonance and provide us with useful knowledge for the development of metal-oxide nano-hybrid materials for solar energy conversion. PMID:25700130

  12. CHEMICALS

    CERN Multimedia

    Medical Service

    2002-01-01

    It is reminded that all persons who use chemicals must inform CERN's Chemistry Service (TIS-GS-GC) and the CERN Medical Service (TIS-ME). Information concerning their toxicity or other hazards as well as the necessary individual and collective protection measures will be provided by these two services. Users must be in possession of a material safety data sheet (MSDS) for each chemical used. These can be obtained by one of several means : the manufacturer of the chemical (legally obliged to supply an MSDS for each chemical delivered) ; CERN's Chemistry Service of the General Safety Group of TIS ; for chemicals and gases available in the CERN Stores the MSDS has been made available via EDH either in pdf format or else via a link to the supplier's web site. Training courses in chemical safety are available for registration via HR-TD. CERN Medical Service : TIS-ME :73186 or service.medical@cern.ch Chemistry Service : TIS-GS-GC : 78546

  13. Evaluation of the effect of conventionally prepared swarna makshika bhasma on different bio-chemical parameters in experimental animals

    Directory of Open Access Journals (Sweden)

    Sudhaldev Mohapatra

    2011-01-01

    Full Text Available Swarna makshika (chalcopyrite bhasma (SMB has been used for different therapeutic purposes since long in Ayurveda. The present study is conducted to evaluate the effect of conventionally prepared SMB on different bio-chemical parameters in experimental animals, for providing scientific data base for its logical use in clinical practice. The genuine SMB was prepared by following classical techniques of shodhana and marana most commonly used by different Ayurvedic drug manufacturers. Shodhana was done by roasting raw swarna makshika with lemon juice for three days and marana was performed by 11 putas . The experimental animals (rats were divided into two groups. SMB mixed with diluted honey was administered orally in therapeutic dose to Group SMB and diluted honey only was administered to vehicle control Group, for 30 days. The blood samples were collected twice, after 15 days and after 30 days of drug administration and different biochemical investigations were done. Biochemical parameters were chosen based on references from Ayurvedic classics and contemporary medicine. It was observed that Hb% was found significantly increased and LDL and VLDL were found significantly decreased in Group SMB when compared with vehicle control group. This experimental data will help the clinician for the logical use of SMB in different disease conditions with findings like low Hb% and high LDL, VLDL levels.

  14. The preparation and chemical reaction kinetics of tungsten bronze thin films and nitrobenzene with and without a catalyst

    Science.gov (United States)

    Materer, Nicholas F.; Apblett, Allen; Kadossov, Evgueni B.; Khan, Kashif Rashid; Casper, Walter; Hays, Kevin; Shams, Eman F.

    2016-06-01

    Microcrystalline tungsten bronze thin films were prepared using wet chemical techniques to reduce a tungsten oxide thin film that was prepared by thermal oxidation of a sputter deposited tungsten metal film on a quartz substrate. The crystallinity of these films was determined by X-ray diffraction and the surface was characterized by X-ray and Ultra-Violet Photoelectron spectroscopy. The total amount of hydrogen incorporated in the film was monitored using absorbance spectroscopy at 900 nm. The oxidation kinetics of the film and the hydrogenation of nitrobenzene in hexane were measured as a function of film thickness. A satisfactory fit of the resulting kinetics was obtained using a model that involves two simultaneous processes. The first one is the proton diffusion from the bulk of the film to the surface, and the second is a reaction of the surface protons with the oxidants. Finally, the dependence of the reaction rates on the presence of catalytic amounts of first row transition metals on the surface of the film was explored.

  15. Superconducting MgB2 film prepared by chemical vapor deposition at atmospheric pressure of N2

    International Nuclear Information System (INIS)

    A simple and effective chemical vapor deposition equipment was developed for deposition of superconducting MgB2 thin films. The pure precursor Boron films were prepared in base pressure of low vacuum and deposited in atmospheric pressure. After the precursor film annealed in Mg vapor, the superconducting MgB2 film was fabricated. During the precursor Boron films preparation, N2 and Ar were used as carrier gas. Compared to Ar gas, the films show better crystallization, surface morphology and superconducting performance when N2 is adopted as carrier gas. With flow rate of 200 sccm of N2 gas, the fabricated MgB2 films exhibit the highest superconducting transition temperature of 39.5 K, which is among the best results of MgB2 thin films. This method provides a suitable method to realize high quality MgB2 Josephson junctions and industrial manufacture of MgB2 superconducting thin films on a large scale. - Highlights: • Boron films were deposited in atmospheric pressure. • Boron films deposited in N2 atmosphere have better morphology than that of in Ar. • MgB2 films show better crystallization and superconductivity in N2 atmosphere

  16. Studies on Hall Effect and DC Conductivity Measurements of Semiconductor Thin films Prepared by Chemical Bath Deposition (CBD method

    Directory of Open Access Journals (Sweden)

    S. Thirumavalavana

    2015-12-01

    Full Text Available Semiconductors have various useful properties that can be exploited for the realization of a large number of high performance devices in fields such as electronics and optoelectronics. Many novel semiconductors, especially in the form of thin films, are continually being developed. Thin films have drawn the attention of many researchers because of their numerous applications. As the film becomes thinner, the properties acquire greater importance in the miniaturization of elements such as resistors, transistors, capacitors, and solar cells. In the present work, copper selenide (CuSe, cadmium selenide (CdSe, zinc selenide (ZnSe, lead sulphide (PbS, zinc sulphide (ZnS, and cadmium sulphide (CdS thin films were prepared by chemical bath deposition (CBD method. The prepared thin films were analyzed by using Hall measurements in Van Der Pauw configuration (ECOPIA HMS-3000 at room temperature. The Hall parameters such as Hall mobility of the material, resistivity, carrier concentration, Hall coefficient and conductivity were determined. The DC electrical conductivity measurements were also carried out for the thin films using the conventional two – probe technique. The activation energies were also calculated from DC conductivity studies.

  17. Effect of Gamma Radiation on Microbial load, Chemical and Sensory Properties of Sheesh Tawoq, Prepared Chilled Meal

    International Nuclear Information System (INIS)

    Locally prepared meal Sheesh Tawoq was treated with 0, 2, 4 or 6 kGy doses of gamma irradiation. Treated and untreated Sheesh Tawoq were kept in a refrigerator (1 and 4 mC). Microbiological, chemical and sensory characteristics of Sheesh Tawoq were evaluated at 0, 4, 8, 12, 16 and 20th week of storage. The results indicate that 4 and 6 kGy doses of gamma irradiation decreased the total counts of mesophilic aerobic bacteria, total coliform and yeast. Thus the microbiological shelf-life of Sheesh Tawoq was significantly extended from 12 weeks (control) to more than 20 weeks (samples treated with 4 or 6 kGy). Irradiation doses did not have a significant effect on the major constituents of Sheesh Tawoq (moisture, protein and fats). The radiation doses required to reduce the microorganisms load one log cycle (D10 ) in Sheesh Tawoq were 435 and 385 Gy for the Salmonella and E. coli , respectively. The chemical parameters, total acidity and volatile basic nitrogen, which were chosen as the indices of freshness, were all well within the acceptable limit for up to 12 weeks for Sheesh Tawoq treated with 0 and 2 kGy, and for up to 20 weeks at 1 and 4 mC for samples treated with 4 and 6 kGy. Sensory evaluation showed no significant differences between irradiated and non-irradiated samples. (author)

  18. Effects of Thermal Annealing on the Optical Properties of Titanium Oxide Thin Films Prepared by Chemical Bath Deposition Technique

    Directory of Open Access Journals (Sweden)

    H.U. Igwe

    2010-08-01

    Full Text Available A titanium oxide thin film was prepared by chemical bath deposition technique, deposited on glass substrates using TiO2 and NaOH solution with triethanolamine (TEA as the complexing agent. The films w ere subjected to post deposition annealing under various temperatures, 100, 150, 200, 300 and 399ºC. The thermal treatment streamlined the properties of the oxide films. The films are transparent in the entire regions of the electromagnetic spectrum, firmly adhered to the substrate and resistant to chemicals. The transmittance is between 20 and 95% while the reflectance is between 0.95 and 1%. The band gaps obtained under various thermal treatments are between 2.50 and 3.0 ev. The refractive index is between 1.52 and 2.55. The thickness achieved is in the range of 0.12-0.14 :m.These properties of the oxide film make it suitable for application in solar cells: Liquid and solid dye-sensitized photoelectrochemical solar cells, photo induced water splitting, dye synthesized solar cells, environmental purifications, gas sensors, display devices, batteries, as well as, solar cells with an organic or inorganic extremely thin absorber. These thin films are also of interest for the photooxidation of water, photocatalysis, electro chromic devices and other uses.

  19. Preparation of Fe-doped colloidal SiO(2) abrasives and their chemical mechanical polishing behavior on sapphire substrates.

    Science.gov (United States)

    Lei, Hong; Gu, Qian; Chen, Ruling; Wang, Zhanyong

    2015-08-20

    Abrasives are one of key influencing factors on surface quality during chemical mechanical polishing (CMP). Silica sol, a widely used abrasive in CMP slurries for sapphire substrates, often causes lower material removal rate (MRRs). In the present paper, Fe-doped colloidal SiO2 composite abrasives were prepared by a seed-induced growth method in order to improve the MRR of sapphire substrates. The CMP performance of Fe-doped colloidal SiO2 abrasives on sapphire substrates was investigated using UNIPOL-1502 CMP equipment. Experimental results indicate that the Fe-doped colloidal SiO2 composite abrasives exhibit lower surface roughness and higher MRR than pure colloidal SiO2 abrasives for sapphire substrates under the same testing conditions. Furthermore, the acting mechanism of Fe-doped colloidal SiO2 composite abrasives in sapphire CMP was analyzed by x-ray photoelectron spectroscopy. Analytical results show that the Fe in the composite abrasives can react with the sapphire substrates to form aluminum ferrite (AlFeO3) during CMP, which promotes the chemical effect in CMP and leads to improvement of MRR. PMID:26368752

  20. Effect of gamma irradiation on the microbial load and chemical and sensory properties of locally prepared fast meals

    International Nuclear Information System (INIS)

    Locally prepared meals (kubba, borak, cheese borak and sheesh tawoq) were treated with 2, 4 or 6 kGy doses of gamma irradiation. Treated and untreated samples were kept in a refrigerator (1-4 deg. C). Microbiological and chemical analyses were performed on each treated sample immediately after processing, and weekly throughout the storage period, which lasted for 3 weeks for kubba, 6 weeks for borak and cheese borak and 20 weeks for sheesh tawoq. Sensory evaluation and proximate analysis were done within one week after irradiation. Results of the proximate analysis of borak, cheese borak and sheesh tawoq showed that the irradiation doses did not have a significant effect on the moisture, protein and fat contents of meals, whereas for kubba, irradiation decreased the moisture, protein and fat contents. The doses of gamma irradiation selected decreased the microorganism load and increased the shelf life of all meals studied. The radiation doses required to reduce Salmonella and Escherichia coli by one log cycle (D10) in borak were 0.46 and 0.51 kGy, in cheese borak 0.30 and 0.50 kGy and for sheesh tawoq 0.44 and 0.39 kGy, respectively. The three chemical parameters, total acidity, lipid peroxide and volatile basic nitrogen, which were chosen as the indices of freshness, were all well within the acceptable limit for up to 3 weeks for kubba, 6 weeks for borak and cheese borak and 20 weeks for sheesh tawoq treated with 6 kGy. Sensory evaluation showed no significant differences between irradiated and non-irradiated samples. (author)

  1. TiO2 based photo-catalysts prepared by chemical vapor infiltration (CVI) on micro-fibrous substrates

    International Nuclear Information System (INIS)

    This thesis deals with micro-fibrous glass substrates functionalized with TiO2. The oxide is deposited as a thin film onto the micro fibres by chemical vapour infiltration (CVI), yielding a photo-catalytic material usable for cleaning polluted air. We studied the relation between the structure of the material and its photo-catalytic efficiency. TiO2 thin films were prepared at low pressure, in a hot-wall CVD reactor, using Ti(O-iPr)4 as a precursor. They were characterized by XRD, SEM, EDX, XPS and BET, and by recording the kinetics of decomposition of varied pollutants in solution (orange G, malic acid, imazapyr) and in air (toluene). The conditions favoring the growth of porous films through a columnar growth mode were established by MOCVD-depositing TiO2 thin films on flat substrates. The subsequent works with micro fibrous thick substrates showed the uniformity of infiltration to be the main factor governing the photo-catalytic efficiency. Operating parameters that optimize infiltration do not yield columnar growth mode. A compromise is necessary. Our photo-catalysts are showing high efficiency comparable, if not higher, to those actually commercialized. These promising results are opening real perspectives for the proposed process. (author)

  2. In situ high temperature XRD studies of ZnO nanopowder prepared via cost effective ultrasonic mist chemical vapour deposition

    Indian Academy of Sciences (India)

    Preetam Singh; Ashvani Kumar; Ajay Kaushal; Davinder Kaur; Ashish Pandey; R N Goyal

    2008-06-01

    Ultrasonic mist chemical vapour deposition (UM–CVD) system has been developed to prepare ZnO nanopowder. This is a promising method for large area deposition at low temperature inspite of being simple, inexpensive and safe. The particle size, lattice parameters and crystal structure of ZnO nanopowder are characterized by in situ high temperature X-ray diffraction (XRD). Surface morphology of powder was studied using transmission electron microscopy (TEM) and field emission electron microscope (FESEM). The optical properties are observed using UV-visible spectrophotometer. The influence of high temperature vacuum annealing on XRD pattern is systematically studied. Results of high temperature XRD showed prominent 100, 002 and 101 reflections among which 101 is of highest intensity. With increase in temperature, a systematic shift in peak positions towards lower 2 values has been observed, which may be due to change in lattice parameters. Temperature dependence of lattice constants under vacuum shows linear increase in their values. Diffraction patterns obtained from TEM are also in agreement with the XRD data. The synthesized powder exhibited the estimated direct bandgap (g) of 3.43 eV. The optical bandgap calculated from Tauc’s relation and the bandgap calculated from the particle size inferred from XRD were in agreement with each other.

  3. Thermal shock behavior of W-0.5 wt% Y2O3 alloy prepared via a novel chemical method

    Science.gov (United States)

    Zhao, Mei-Ling; Luo, Lai-Ma; Lin, Jing-Shan; Zan, Xiang; Zhu, Xiao-Yong; Luo, Guang-Nan; Wu, Yu-Cheng

    2016-10-01

    A wet-chemical method combined with spark plasma sintering was used to prepare W-0.5 wt% Y2O3 alloy. The W-0.5 wt% Y2O3 precursor was reduced at 800 °C for 4 h under different hydrogen flow rates of 300, 400, 500, 600, and 700 ml/min. The reduced powder was analyzed by X-ray diffraction (XRD), laser particle size analyzer (LPSA), and scanning electron microscopy (SEM). An optimized process for reducing precursor was discussed. After sintering, the specimens were exposed to different laser beam irradiation energies (90, 120, 150, and 180 W) to simulate loads as expected for edge localized modes (ELMs). Top surface and cross-sectional morphology were observed by SEM, and the changes in hardness were evaluated. The changes in microstructural properties (i.e., Y2O3-particle distribution, crack propagation direction, depth of thermal shock effect, and grain size of the recrystallization region) after thermal shock were investigated.

  4. Preparation and characteristics of C/C composite brake disc by multi-cylindrical chemical vapor deposition processes

    Institute of Scientific and Technical Information of China (English)

    YUAN Yi-dong; ZHANG Fu-kuan; ZHOU Wan-cheng

    2005-01-01

    The C/C composite brake discs were prepared by tri-cylindrical chemical vapor deposition (CVD) process. The optimum processing parameters were as follows: deposition temperature was 830-930 ℃, the gas-flow rates of N2 and propylene were 4.8-5.2 m3/h and 5.8-6.2 m3/h, respectively, the furnace pressure was 4.5-5.5 kPa and the deposition time was 200 h.The effects of processing parameters on the densified rates, thermal-physical property and mechanical performance of C/C composite brake discs were studied. The results show that density, heat conductivity, bend strength and abrasion ratio of the multi-cylindrica brake discs are 1.02-1.78 g/cm3, 31 W/(m·K), 114 MPa and 7 μm/s, respectively, which are approximately similar to those of the single-cylindrical ones. The gas flow rate has no relation to the number of the cylinder and furnace loading. The utilization ratio of carbon can be improved by multi-cylinder CVD process without changing the characteristics of brake disc.

  5. Characterization of electro-conductive fabrics prepared by in situ chemical and electrochemical polymerization of pyrrole onto polyester fabric

    Energy Technology Data Exchange (ETDEWEB)

    Maiti, Syamal; Das, Dipayan; Sen, Kushal, E-mail: kushal@textile.iitd.ernet.in

    2014-09-15

    Highlights: • Surface resistivity of the fabrics decreased rapidly with an increase in add-on. • Add-on and resistivity were not correlated below a resistivity value of about 200 Ω. • Higher add-on but lower surface roughness resulted in lower surface resistivity. • The voltage–current and voltage–temperature behaviours were found to be non-linear. • Electro-conductive fabric exhibited 98% electromagnetic shielding efficiency. - Abstract: This paper reports a study on electro-conductive fabrics prepared by a combined in situ chemical and electrochemical polymerization of pyrrole. Specific observations are made to establish the roles of add-on and surface roughness on the surface resistivity of the electro-conductive fabrics. The performance characteristics of the fabrics are reported in terms of electrical conductivity, voltage–current and voltage–temperature characteristics and electromagnetic interference (EMI) shielding capability. The surface resistivity of the fabric was found to be as low as 11.79 Ω. The voltage–current profile of the fabric is observed to be non-ohmic as well as the voltage–temperature curve is found to be exponential. The EMI shielding efficiency of the fabric was found to be about 98%.

  6. Preparation of Fish Oil Triglyceride by Chemical Catalysis%化学催化制备鱼油三甘酯

    Institute of Scientific and Technical Information of China (English)

    毛治国; 刘明; 张春枝; 张显仁; 徐维锋; 吴文忠

    2012-01-01

    [目的]用化学催化方法制备鱼油三甘酯.[方法]采用酯交换反应,以鱼油乙酯和醋酸三甘酯为原料,制备三甘酯型鱼油,同时研究催化剂种类及用量(基于醋酸三甘酯的质量)、反应温度、物料比(油乙酯和醋酸三甘酯的摩尔比)、反应时间对鱼油三甘酯制备的影响,并通过液相色谱对鱼油三甘酯产物的成分进行定量分析.[结果]制备鱼油三甘酯的最佳条件为:催化剂为甲醇钠,用量为三甘酯质量的3.0%,反应温度为100℃,物料比为鱼油乙酯过量5%(相对于醋酸三甘酯),反应时间为2h.在此最佳条件下制备产物三甘酯含量大于80%.[结论]通过此方法可实现鱼油乙酯向鱼油三甘酯的转化,成本较低,扩大了鱼油类产品在医药和保健品中的应用.%[ Objective] The aim was to prepare fish oil triglyceride by the chemical catalysis method. [ Method] Taking fish oil ethyl ester and glycerol triacetate as raw materials, prepare fish oil triglyceride by transesterification. Then to study the effects of the kind of catalyst and the amount of it (based on the mass of glycerol triacetate) , reaction temperature, mole ratio of fish oil ethyl ester to glycerol triacetate,reaction time on the preparation of fish oil triglyceride. And the composition of the product was analyzed by liquid chromatography quantitatively. [ Result] The optimum conditions of the preparation of fish oil triglyceride were as follows: sodium methoxide was as a catalyst and the amount of it was 3.0% , reaction temperature was 100 t, mole ratio between glycerol triacetate and fish oil ethyl ester was 5% more of fish oil ethyl ester, reaction time was 2 h. Under these conditions, the content of fish oil triglyceride in the product was above 80%. [ Conclusion] This method can be achieved the conversion of fish oil ethyl ester to fish oil triglyceride, and has lower cost, can expand the application of fish oil products in the medicine and health

  7. Chemical approach to solvent removal during nanoencapsulation: its application to preparation of PLGA nanoparticles with non-halogenated solvent

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Youngme [Ewha Womans University, College of Pharmacy (Korea, Republic of); Sah, Eric [University of Notre Dame, College of Science (United States); Sah, Hongkee, E-mail: hsah@ewha.ac.kr [Ewha Womans University, College of Pharmacy (Korea, Republic of)

    2015-11-15

    The objective of this study was to develop a new oil-in-water emulsion-based nanoencapsulation method for the preparation of PLGA nanoparticles using a non-halogenated solvent. PLGA (60–150 mg) was dissolved in 3 ml of methyl propionate, which was vortexed with 4 ml of a 0.5–4 % polyvinyl alcohol solution. This premix was sonicated for 2 min, added into 30 ml of the aqueous polyvinyl alcohol solution, and reacted with 3 ml of 10 N NaOH. Solvent removal was achieved by the alkaline hydrolysis of methyl propionate dissolved in an aqueous phase into water-soluble methanol and sodium propionate. It was a simple but effective technique to quickly harden nanoemulsion droplets into nanoparticles. The appearing PLGA nanoparticles were recovered by ultracentrifugation and/or dialysis, lyophilized with trehalose, and redispersed by water. This nanoencapsulation technique permitted a control of their mean diameters over 151.7 ± 3.8 to 440.2 ± 22.2 nm at mild processing conditions. When the aqueous polyvinyl alcohol concentration was set at ≥1 %, nanoparticles showed uniform distributions with polydispersity indices below 0.1. There were no significant changes in their mean diameters and size distribution patterns before and after lyophilization. When mestranol was encapsulated into nanoparticles, the drug was completely nanoencapsulated: depending on experimental conditions, their encapsulation efficiencies were determined to be 99.4 ± 7.2 to 105.8 ± 6.3 %. This simple, facile nanoencapsulation technique might have versatile applications for the preparation of polymeric nanoparticulate dosage forms.Graphical AbstractSchematic illustration of an innovative chemical approach to solvent removal during nanoencapsulation. Methyl propionate present in the aqueous continuous phase reacts with sodium hydroxide, thereby producing methanol and sodium propionate. Its alkaline hydrolysis allows the continuous extraction of the solvent out of nanoemulsion

  8. Traditional Aboriginal Preparation Alters the Chemical Profile of Carica papaya Leaves and Impacts on Cytotoxicity towards Human Squamous Cell Carcinoma.

    Science.gov (United States)

    Nguyen, Thao T; Parat, Marie-Odile; Shaw, Paul N; Hewavitharana, Amitha K; Hodson, Mark P

    2016-01-01

    Carica papaya leaf decoction, an Australian Aboriginal remedy, has been used widely for its healing capabilities against cancer, with numerous anecdotal reports. In this study we investigated its in vitro cytotoxicity on human squamous cell carcinoma cells followed by metabolomic profiling of Carica papaya leaf decoction and leaf juice/brewed leaf juice to determine the effects imparted by the long heating process typical of the Aboriginal remedy preparation. MTT assay results showed that in comparison with the decoction, the leaf juice not only exhibited a stronger cytotoxic effect on SCC25 cancer cells, but also produced a significant cancer-selective effect as shown by tests on non-cancerous human keratinocyte HaCaT cells. Furthermore, evidence from testing brewed leaf juice on these two cell lines suggested that the brewing process markedly reduced the selective effect of Carica papaya leaf on SCC25 cancer cells. To tentatively identify the compounds that contribute to the distinct selective anticancer activity of leaf juice, an untargeted metabolomic approach employing Ultra High Performance Liquid Chromatography-Quadrupole Time of Flight-Mass Spectrometry followed by multivariate data analysis was applied. Some 90 and 104 peaks in positive and negative mode respectively were selected as discriminatory features from the chemical profile of leaf juice and >1500 putative compound IDs were obtained via database searching. Direct comparison of chromatographic and tandem mass spectral data to available reference compounds confirmed one feature as a match with its proposed authentic standard, namely pheophorbide A. However, despite pheophorbide A exhibiting cytotoxic activity on SCC25 cancer cells, it did not prove to be the compound contributing principally to the selective activity of leaf juice. With promising results suggesting stronger and more selective anticancer effects when compared to the Aboriginal remedy, Carica papaya leaf juice warrants further study

  9. YBa{sub 2}Cu{sub 3}O{sub 7-x} thin films prepared by chemical solution deposition

    Energy Technology Data Exchange (ETDEWEB)

    Apetrii, Claudia

    2009-11-25

    The discovery of superconductivity in ceramic materials by Bednorz and Mueller in early 1987, immediately followed by Wu et al., who showed that YBa{sub 2}Cu{sub 3}O{sub 7-x} (YBCO) becomes superconducting (92 K) well above the boiling point of nitrogen (77 K) created a great excitement in superconductivity research. Potential applications of high T{sub c}-superconductors require large critical currents and high-applied magnetic fields. Effective ways to increase the critical current density at high magnetic fields in YBCO are the introduction of nanoparticles and chemical substitution of yttrium by other rare earth elements. Since low costs and environmental compatibility are essential conditions for the preparation of long length YBCO films, the cost effective chemical solution deposition (CSD) procedure was selected, given that no vacuum technology is required. To reveal the flexibility and the good optimization possibilities of the CSD approach two main processes were chosen for comparison: a fluorine-free method, namely the polymer-metal precursor technique, and a fluorine-based method, the metalorganic deposition (MOD) using the trifluoroacetates (TFA) technique. Sharp transition temperature widths {delta}T{sub c} of 1.1 K for the polymer metal method, 0.8 K for TFA method and critical current densities J{sub c} of {approx}3.5 MA/cm{sup 2} shows that high quality YBCO thin films can be produced using both techniques. Especially interesting is the magnetic field dependence of the critical current density J{sub c}(B) of the Y(Dy)BCO (80 %) films showing that for the lower magnetic fields the critical current density J{sub c}(B) is higher for a standard YBCO film, but at fields higher than 4.5 T the critical current density J{sub c}(B) of Y(Dy)BCO is larger than that for the YBCO. Above 8 T, J{sub c}(B) of the Y(Dy)BCO film is more than one order of magnitude higher than in pure YBCO film. (orig.)

  10. First preparation of nanocrystalline zinc silicate by chemical vapor synthesis using an organometallic single-source precursor.

    Science.gov (United States)

    Roy, A; Polarz, S; Rabe, S; Rellinghaus, B; Zähres, H; Kruis, F E; Driess, Matthias

    2004-03-19

    A method is presented to prepare nanocrystalline alpha-Zn(2)SiO(4) with the smallest crystal size reported so far for this system. Our approach combines the advantages of organometallic single-source precursor routes with aerosol processing techniques. The chemical design of the precursor enables the preferential formation of pure zinc silicates. Since gas-phase synthesis reduces intermolecular processes, and keeps the particles small, zinc silicate was synthesized from the volatile organometallic precursor [[MeZnOSiMe(3)](4)], possessing a Zn-methyl- and O-silyl-substituted Zn(4)O(4)-heterocubane framework (cubane), under oxidizing conditions, using the chemical vapor synthesis (CVS) method. The products obtained under different process conditions and their structural evolution after sintering were investigated by using various analytical techniques (powder X-ray diffraction, transmission electron microscopy, EDX analysis, solid-state NMR, IR, Raman, and UV/Vis spectroscopy). The deposited aerosol obtained first (processing temperature 750 degrees C) was amorphous, and contained agglomerates with primary particles of 12 nm in size. These primary particles can be described by a [Zn-O-Si] phase without long-range order. The deposit obtained at 900 degrees C contained particles with embedded nanocrystallites (3-5 nm) of beta-Zn(2)SiO(4), Zn(1.7)SiO(4), and ZnO in an amorphous matrix. On further ageing, the as-deposited particles obtained at 900 degrees C form alpha-Zn(2)SiO(4) imbedded in amorphous SiO(2). The crystallite sizes and primary particle sizes in the formed alpha-Zn(2)SiO(4) were found to be below approximately 50 nm and mainly spherical in morphology. A gas-phase mechanism for the particle formation is proposed. In addition, the solid-state reactions of the same precursor were studied in detail to investigate the fundamental differences between a gas-phase and a solid-state synthesis route.

  11. Densification and microstructure of carbon/carbon composites prepared by chemical vapor infiltration using ethanol as precursor

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Chemical vapor infiltration of carbon fiber felts with uniform initial bulk density of 0.47 g·cm-3 was investigated at the ethanol partial pressures of 5-20 kPa,as well as the temperatures of 1050,1100,1150 and 1200°C.Ethanol,diluted by nitrogen,was employed as the precursor of pyrolytic carbon.Polarized light microscopy(PLM),scanning electron microscopy and X-ray diffraction were adopted to study the texture of pyrolytic carbon deposited at various temperatures.A change from medium-to high-textured pyrolytic carbon was observed in the sample infiltrated at 1050°C.Whereas,homogeneous high-textured pyrolytic carbons were deposited at the temperatures of 1100,1150 and 1200°C.Extinction angles of 19°-21° were determined for different regions in the samples densified at the temperatures ranging from 1100 to 1200°C.Scanning electron microscopy of the fracture surface after bending test indicated that the prepared carbon/carbon composite samples exhibited a pseudo-plastic fracture behavior.In addition,fracture behavior of the carbon/carbon samples was obviously effected by their infiltration temperature.The fracture mode of C/C composites was transformed from shearing failure to tensile breakage with increasing infiltration temperature. Results of this study show that ethanol is a promising carbon source to synthesize carbon/carbon composites with homogeneously high-textured pyrolytic carbon over a wide range of temperatures(from 1100 to 1200°C).

  12. Comparison of the Er,Cr:YSGG laser with a chemical vapour deposition bur and conventional techniques for cavity preparation: a microleakage study.

    Science.gov (United States)

    Yazici, A Rüya; Yıldırım, Zeren; Antonson, Sibel A; Kilinc, Evren; Koch, Daniele; Antonson, Donald E; Dayangaç, Berrin; Ozgünaltay, Gül

    2012-01-01

    The aim of this study was to compare the effects of the Er,Cr:YSGG laser using chemical vapour deposition (CVD) bur cavity preparation with conventional preparation methods including a diamond bur and a carbide bur on the microleakage with two different adhesive systems. A total of 40 extracted human premolars were randomly assigned to four experimental groups according to the cavity preparation technique: group I diamond bur (Diatech); group II carbide bur (Diatech); group III Er,Cr:YSGG laser (Biolase Millennium II); and group IV CVD bur (CVDentUS). Using the different preparation techniques, Class V standardized preparations were performed on the buccal and lingual surfaces with gingival margins on the dentin and occlusal margins on the enamel. Each preparation group was randomly assigned to two subgroups (five teeth, ten preparations) according to the type of adhesive: an etch-and-rinse adhesive (Adper Single Bond), and a single-step self-etch adhesive (AdheSE One). All preparations were restored with a nanohybrid composite resin in a single increment. Following thermocycling (×500; 5-55°C), the teeth were immersed in basic fuchsin and sectioned in the orovestibular direction. Dye penetration was evaluated under a light microscope by two blinded examiners. Data were statistically analysed with the Kruskal-Wallis and Wilcoxon tests (p0.05). Comparing the enamel and dentin leakage scores within each group, no statistically significant differences were found (p>0.05). The Er,Cr:YSGG laser cavity preparation did not differ from preparation with CVD, diamond or carbide bur in terms of microleakage with the different adhesive systems.

  13. Annealing effects on zinc oxide-silica films prepared by sol–gel technique for chemical sensing applications

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Atif Mossad, E-mail: atifali@kku.edu.sa [Department of Physics, Faculty of Science, King Khalid University, Abha (Saudi Arabia); Department of Physics, Faculty of Science, Assiut University, Assiut 71516 (Egypt); Ismail, Adel A. [Promising Centre for Sensors and Electronic Devices (PCSED), Najran University, PO Box 1988, Najran 11001 (Saudi Arabia); Central Metallurgical R and D Institute, CMRDI, Helwan, Cairo 11421 (Egypt); Najmy, Rasha [Science Department, Girls' College of Education, King Khalid University (Saudi Arabia); Al-Hajry, Ali [Promising Centre for Sensors and Electronic Devices (PCSED), Najran University, PO Box 1988, Najran 11001 (Saudi Arabia); Department of Physics, College of Science and Arts, Najran University (Saudi Arabia)

    2014-05-02

    ZnO:SiO{sub 2} films are prepared by sol–gel technique on Si substrates. The effect of annealing temperatures (T{sub a}) on the structure, surface morphology, and optical and photoluminescence (PL) properties of these films is studied. The X-ray diffraction analysis revealed that the c-axis orientation and the grain size of ZnO:SiO{sub 2} films increased at high T{sub a}. High-resolution transmission electron microscopy results showed that the ZnO nanoparticles are spherical in shape with their size increasing from 5 to 15 nm with T{sub a} while PL spectroscopy showed few separated PL bands. In addition, two optical band gaps located at 3.0 eV and 4.2 eV are observed and showed a redshift with T{sub a} up to 600 °C, and then a blueshift is observed at 800 °C. ZnO:SiO{sub 2} film was tested as sensors for the detection and quantification of phenyl hydrazine. It is found that ZnO:SiO{sub 2} films showed good sensitivity of 390 μA mM{sup −1} cm{sup −2} and a lower limit of detection of 3 mM with linear dynamic range of 0.05 mM to 3 mM and rapid reaction kinetics (in the order of seconds). The cycling tests indicated that the ZnO:SiO{sub 2} films are quite stable since no significant decrease in sensitivity was observed even after being used repetitively for 3 times, showing a good potential for practical applications. - Highlights: • The nanoparticles size increased from 5 to 15 nm with the annealing temperatures. • Two optical band gaps located at 3.0 eV and 4.2 eV are observed. • ZnO:SiO{sub 2} showed good sensitivity and lower limit of detection. • Cycling test indicated ZnO:SiO{sub 2} was stable during liquid–solid chemical sensing.

  14. Preparation, Biodegradation of Coconut Oil Driven Chemically Modified Bovine Serum Albumin Microparticles of Encapsulated Cicer arietinum Amylase and Study of Their Application in Washing Detergents

    OpenAIRE

    Kirti Rani; Vartika Mehta

    2014-01-01

    In present work, Cicer arietinum amylase was encapsulated by emulsification through covalent coupling by glutaraldehyde into chemically modified bovine serum albumin. Biodegradation of coconut oil driven emulsified bovine serum albumin encapsulated Cicer arietinum amylase was carried out by the alkaline protease for its controlled and sustained release of encapsulated enzyme from prepared microparticles of encapsulated Cicer arietinum amylase and its stability increased up to 6 months as comp...

  15. Preparation of Pt-Ru@ polypyrrole-MWNT catalysts by gamma-irradiation and chemical reduction and their adsorption capacity for CO.

    Science.gov (United States)

    Bae, Hyoung-Bong; Oh, Sang-Hyub; Woo, Jin-Chun; Choi, Seong-Ho

    2010-10-01

    With the objective to prepare electrocatalysts with high efficiency, the Pt-Ru@PPy-MWNT catalysts were prepared by different approaches. First, the polypyrrole (PPy) as anchoring materials was coated on the surface of multi walled carbon nanotubes (MWNT) by in situ polymerization. Subsequently, Pt-Ru nanoparticles were deposited onto PPy-MWNT composite by different methods like the reduction of metal ions by gamma-irradiation and chemical reduction using formaldehyde as reducing agent assisted with stirring of magnetic bar, and assisted with microwave irradiation, and assisted with ultrasonic irradiation, in order to prepare electrocatalyst for fuel cell. The catalytic efficiency of Pt-Ru@PPy-MWNT catalyst was examined for CO stripping.

  16. Sol-gel process preparation and evaluation of the analytical performances of an hydrazine specific chemical sensor

    International Nuclear Information System (INIS)

    The realisation of optical fibers active chemical collector to analyze hydrazine in line, in the spent fuel reprocessing process is the subject of this work. The p.dimethyl-amino-benzaldehyde has been chosen as reagent for its chemical and optical properties

  17. Combining Chemical Information Literacy, Communication Skills, Career Preparation, Ethics, and Peer Review in a Team-Taught Chemistry Course

    Science.gov (United States)

    Jones, Mary Lou Baker; Seybold, Paul G.

    2016-01-01

    The widely acknowledged need to include chemical information competencies and communication skills in the undergraduate chemistry curriculum can be accommodated in a variety of ways. We describe a team-taught, semester-length course at Wright State University which combines chemical information literacy, written and oral communication skills,…

  18. Preparation of LWBR [Light Water Breeder Reactor] spent fuel for shipment to ICPP [Idaho Chemical Processing Plant] for long term storage (LWBR Development Program)

    International Nuclear Information System (INIS)

    After successfully operating for 29,047 effective full power hours, the Light Water Breeder Reactor (LWBR) core was defueled prior to total decommissioning of the Shippingport facility. All nuclear fuel and much of the reactor internal hardware was removed from the reactor vessel. Non-fuel components were prepared for shipment to disposal sites, and the fuel assemblies were partially disassembled and shipped to the Expended Core Facility (ECF) in Idaho. At ECF, the fuel modules underwent further disassembly to provide fuel rods for nondestructive testing to establish the core's breeding efficiency and to provide core components for examinations to assess their performance characteristics. This report presents a basic description of the processes and equipment used to prepare and to ship all LWBR nuclear fuel to the Idaho Chemical Processing Plant (ICPP) for long-term storage. Preparation processes included the underwater loading of LWBR fuel into storage liners, the sealing, dewatering and drying of the storage liners, and the final pressurization of the storage liners with inert neon gas. Shipping operations included the underwater installation of the fuel loaded storage liner into the Peach Bottom shipping cask, cask removal from the waterpit, cask preparations for shipping, and cask shipment by tractor trailer to the ICPP facility for long-term storage. The ICPP facility preparations for LWBR fuel storage and the ICPP process for discharge of the fuel into underground silos are presented. 10 refs., 42 figs

  19. Storage stability of margarines produced from enzymatically interesterified fats compared to those prepared by conventional methods - Chemical properties

    DEFF Research Database (Denmark)

    Zhang, Hong; Jacobsen, Charlotte; Pedersen, Lars Saaby;

    2006-01-01

    In this study, four margarine hardstocks were produced, two from enzymatically interesterified fats at 80 and 100% conversion, one from chemically randomized fat and one from physically mixed fat. These four hardstocks, blended with 50% sunflower oil, were mainly used for the production of table......) and to selected commercial margarines. The changes in the chemical properties of the products, including peroxide values (PV), tocopherols, free fatty acids, volatile oxidation products, and sensory evaluation, were examined during storage. It was observed that the margarine produced from the chemically...

  20. Three-dimensional assemblies of graphene prepared by a novel chemical reduction-induced self-assembly method

    KAUST Repository

    Zhang, Lianbin

    2012-01-01

    In this study, three-dimensional (3D) graphene assemblies are prepared from graphene oxide (GO) by a facile in situ reduction-assembly method, using a novel, low-cost, and environment-friendly reducing medium which is a combination of oxalic acid (OA) and sodium iodide (NaI). It is demonstrated that the combination of a reducing acid, OA, and NaI is indispensable for effective reduction of GO in the current study and this unique combination (1) allows for tunable control over the volume of the thus-prepared graphene assemblies and (2) enables 3D graphene assemblies to be prepared from the GO suspension with a wide range of concentrations (0.1 to 4.5 mg mL-1). To the best of our knowledge, the GO concentration of 0.1 mg mL-1 is the lowest GO concentration ever reported for preparation of 3D graphene assemblies. The thus-prepared 3D graphene assemblies exhibit low density, highly porous structures, and electrically conducting properties. As a proof of concept, we show that by infiltrating a responsive polymer of polydimethylsiloxane (PDMS) into the as-resulted 3D conducting network of graphene, a conducting composite is obtained, which can be used as a sensing device for differentiating organic solvents with different polarity. © 2012 The Royal Society of Chemistry.

  1. Influence of TEM specimen preparation on chemical composition of Pb(Mg1/3Nb2/3)O3-PbTiO3 single crystals.

    Science.gov (United States)

    Srot, Vesna; Gec, Medeja; van Aken, Peter A; Jeon, Jae-Ho; Ceh, Miran

    2014-07-01

    The influences of different transmission electron microscopy (TEM) specimen preparation techniques on the chemical composition of Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) single crystals was studied. Ion-milled samples where no cooling with liquid nitrogen (L-N2) was applied show permanently changed composition also deep inside the bulk material. When the PMN-PT samples were cooled to L-N2 temperature during the ion-milling process and in addition lower accelerating voltages were used, the chemical composition was altered only in the thinnest parts close to the specimen edge. Samples prepared using only tripod polishing technique show compositional irregularities close to the specimen edge. For the preparation of lead-containing samples, such as PMN-PT single crystals, a combination of tripod polishing and short Ar-ion-milling at low accelerating voltages while cooling the samples to liquid nitrogen temperature proved to be the most suitable to obtain artefact-free electron-transparent TEM lamellae. PMID:24811990

  2. Synthesis and photocatalytic activity of TiO2 nanoparticles prepared by chemical vapor condensation method with different precursor concentration and residence time.

    Science.gov (United States)

    Chin, Sungmin; Park, Eunseuk; Kim, Minsu; Bae, Gwi-Nam; Jurng, Jongsoo

    2011-10-15

    Nanosized TiO(2) photocatalysts were synthesized using a chemical vapor condensation method under a range of synthesis conditions (precursor vapor concentration and residence time in a tubular electric furnace). X-ray diffraction showed that the prepared TiO(2) powders consisted mainly of anatase (>94%) with a small amount of rutile. The mean particle diameter from the Brunauer-Emmett-Teller surface area and transmission electron microscopy measurements ranged from 9.4 to 16.6 nm. The specific surface area (92.5-163.5 m(2) g(-1)) of the prepared TiO(2) powders was found to be dependent on the synthesis conditions. The content of hydroxyl groups on the surface of the prepared TiO(2) sample was higher than those on commercial TiO(2), resulting in increased photocatalytic oxidation. The photocatalytic activity of the TiO(2) samples prepared in a methylene blue solution was strongly dependent on the crystallinity and specific surface area, which were affected by the TTIP vapor concentration and residence time. PMID:21802692

  3. Effects of drying control chemical additive on properties of Li 4Ti 5O 12 negative powders prepared by spray pyrolysis

    Science.gov (United States)

    Ju, Seo Hee; Kang, Yun Chan

    High-density Li 4Ti 5O 12 powders comprising spherical particles are prepared by spray pyrolysis from a solution containing dimethylacetamide (drying control chemical additive) and citric acid and ethylene glycol (organic additives). The prepared powders have high discharge capacities and good cycle properties. The optimum concentration of dimethylacetamide is 0.5 M. The addition of dimethylacetamide to the polymeric spray solutions containing citric acid and ethylene glycol helps in the effective control of the morphology of the Li 4Ti 5O 12 powders. At a constant current density of 0.17 mA g -1, the initial discharge capacities of the powders obtained from the spray solution with and without the organic additives are 171 and 167 mAh g -1, respectively.

  4. STORAGE OF CHEMICALLY PRETREATED WHEAT STRAW – A MEANS TO ENSURE QUALITY RAW MATERIAL FOR PULP PREPARATION

    Directory of Open Access Journals (Sweden)

    Terttu Heikkilä

    2010-07-01

    Full Text Available The aim of this study was to evaluate effects of chemical pretreatment and storage on non-wood pulping and on pulp quality. The processes studied were hot water treatment followed by alkaline peroxide bleaching or soda cooking. The results showed that it is possible to store wheat straw outside for at least one year without significant changes in the raw material chemical composition and without adverse effects on the resulting pulp quality. The results are significant to the industry using non-woods to ensure the availability and the quality of the raw-material throughout the year in spite of the short harvesting time.

  5. Rapid mixing chemical oxidative polymerization: an easy route to prepare PANI coated small-diameter CNTs/PANI nanofibres composite thin film

    Indian Academy of Sciences (India)

    G Venkata Ramana; Balaji Padya; Vadali V S S Srikanth; P K Jain

    2014-05-01

    Composite thin film containing polyaniline (PANI) coated small diameter carbon nanotubes (SDCNTs)/PANI nanofibres (NFs) has been prepared using an easy in situ rapid mixing chemical oxidative polymerization method. SDCNTs thin film was obtained using thermal chemical vapour deposition method in a separate experiment, whilst PANI NFs are formed in situ during the synthesis of composite. In the composite, PANI coated SDCNTs are uniformly distributed among PANI NFs. The presence of SDCNTs during the composite synthesis does not influence the nucleation and growth of PANI NFs. Raman analysis shows a good interaction between PANI and SDCNTs. Room temperature d.c. electrical sheet resistance of SDCNTs/PANI NFs composite thin film surface is three orders lesser than that of PANI NFs thin film (PANI NFs have the same morphology as in the composite) synthesized using the same method but without the presence of SDCNTs.

  6. [Analysis of exposure to pepper spray as a part of preparing hospital to help victims of mass chemical incidents].

    Science.gov (United States)

    Chwaluk, Paweł; Topczewska, Elzbieta; Barwina, Małgorzata

    2012-01-01

    We analyzed an incident of exposure to pepper spray 35 persons, including 29 children. Medical procedures were difficult because of the lack of reliable information about the nature of exposure, lack of hospital action plan for chemical accidents and established principles of cooperation with poison control center, as well as the need of extensive medical documentation for each patient. PMID:23243951

  7. Influence of precursor solution parameters on chemical properties of calcium phosphate coatings prepared using Electrostatic Spray Deposition (ESD).

    NARCIS (Netherlands)

    Leeuwenburgh, S.C.G.; Wolke, J.G.C.; Schoonman, J.; Jansen, J.A.

    2004-01-01

    A novel coating technique, referred to as Electrostatic Spray Deposition (ESD), was used to deposit calcium phosphate (CaP) coatings with a variety of chemical properties. The relationship between the composition of the precursor solutions and the crystal and molecular structure of the deposited coa

  8. Effect of growth temperature on the structural of Nd-doped silica prepared by the chemical method

    Energy Technology Data Exchange (ETDEWEB)

    Aghamkar, P. [Materials Science Lab, Department of Applied Physics, Guru Jambheshwar University of Science and Technology, Hisar-125001 (India); Department of Physics, Chaudhary Devi Lal University, Sirsa-125055 (India); Duhan, S. [Materials Science Lab, Department of Applied Physics, Guru Jambheshwar University of Science and Technology, Hisar-125001 (India)], E-mail: surender6561@yahoo.co.in; Kishore, N. [Materials Science Lab, Department of Applied Physics, Guru Jambheshwar University of Science and Technology, Hisar-125001 (India); Lal, Bhajan [Department of Physics, Chaudhary Devi Lal University, Sirsa-125055 (India)

    2009-03-15

    Silica gel doped with Nd{sub 2}O{sub 3} was prepared by solgel method, using tetra-ethoxysilane and Nd (NO{sub 3}){sub 3} as precursor materials and HCl as a catalyst. The prepared samples were submitted to thermal treatments in the temperature range from 600 up to 1200 deg. C. Structural changes were investigated by XRD, FTIR spectroscopy and SEM. The effect of thermal annealing on Nd-containing silica has been discussed in detail. At 900 deg. C (4 h) various structures formed, while a further increase of the temperature and annealing time resulted in the formation of cubic neodymia and neodymium disilicate crystallites. At constant sintering temperature 1200 deg. C for 6 h the samples show distinct formation of Nd{sub 2}O{sub 3} nanocrystallites with average size {approx}16 nm.

  9. Chemical studies on the preparation of magnetic nanoparticles coated with glycine and its application for removal of heavy metals

    Directory of Open Access Journals (Sweden)

    Jawaher Alzaidi

    2016-06-01

    Full Text Available The aim of this study is the preparation of magnetic nanoparticles and coating with glycine to remove heavy metals such as Cu+2. The magnetic nanoparticles were prepared by co-precipitation method using using ferrous sulphate and potassium nitrate in presence of potassium hydroxide. Different instrumental analysis such as XRD, TEM, SEM and EDAX were used to study the magnetic nanoparticles which produced and comparing it after coated with glycine. The optimum conditions which reflect the high efficiency of removal are pH 10, concentration of the heavy metal 200 ppm, dosage 0.05 g and for 24 h duration time. Therefore we recommend using magnetic nanoparticles coated with glycine for removal of heavy metals.

  10. Effect of growth temperature on the structural of Nd-doped silica prepared by the chemical method

    International Nuclear Information System (INIS)

    Silica gel doped with Nd2O3 was prepared by solgel method, using tetra-ethoxysilane and Nd (NO3)3 as precursor materials and HCl as a catalyst. The prepared samples were submitted to thermal treatments in the temperature range from 600 up to 1200 deg. C. Structural changes were investigated by XRD, FTIR spectroscopy and SEM. The effect of thermal annealing on Nd-containing silica has been discussed in detail. At 900 deg. C (4 h) various structures formed, while a further increase of the temperature and annealing time resulted in the formation of cubic neodymia and neodymium disilicate crystallites. At constant sintering temperature 1200 deg. C for 6 h the samples show distinct formation of Nd2O3 nanocrystallites with average size ∼16 nm

  11. Sensory and physico-chemical characteristics of desserts prepared with egg products processed by freeze and spray drying

    OpenAIRE

    Marcelo Nunes de Jesús; Ana Beatriz Zanqui; Patrícia Valderrama; Augusto Tanamati; Swami Arêa Maruyama; Nilson Evelázio de Souza; Makoto Matsushita

    2013-01-01

    In this work, three freeze-dried (FD) egg products (whole egg (WE), egg yolk (EY) and egg white (EW)) were obtained and the acceptability of confections prepared with each was evaluated. Sensory analyses for confections were performed by hedonic testing with fifty panelists in each evaluation. The studied confections were: Condensed Milk Pudding (P), Quindim (Q) and Meringue (M). The results obtained for confections made with FD egg products were compared with the achieved through other formu...

  12. Adsorption of Hexavalent Chromium from Aqueous Solution Using Chemically Activated Carbon Prepared from Locally Available Waste of Bamboo (Oxytenanthera abyssinica)

    OpenAIRE

    Dula, Tamirat; Siraj, Khalid; Kitte, Shimeles Addisu

    2014-01-01

    This study reports on the adsorption of Hexavalent Chromium from aqueous solutions using activated carbon prepared from bamboo (Oxytenanthera abyssinica) waste by KOH activation heating in an electrical furnace at 1073 K for 3 hrs. Batch adsorption experiments were also carried out as a function of pH, contact time, initial concentration of the adsorbate, adsorbent dosage, and temperature of the solution. Kinetic studies of the data showed that the adsorption follows the pseudo-second-order k...

  13. Synthesis and Magnetic Properties of Cobalt Ferrite (CoFe2O4) Nanoparticles Prepared by Wet Chemical Route

    OpenAIRE

    Maaz, K; Mumtaz, Arif; Hasanain, S. K.; CEYLAN, Abdullah

    2006-01-01

    Magnetic nanoparticles of cobalt ferrite have been synthesized by wet chemical method using stable ferric and cobalt salts with oleic acid as the surfactant. X-ray Diffraction (XRD) and Transmission Electron Microscope (TEM) confirmed the formation of single phase cobalt ferrite nanoparticles in the range 15-48nm depending on the annealing temperature and time. The size of the particles increases with annealing temperature and time while the coercivity goes through a maximum, peaking at aroun...

  14. Structural and XPS studies of PSi/TiO2 nanocomposites prepared by ALD and Ag-assisted chemical etching

    International Nuclear Information System (INIS)

    Highlights: • Porous silicon/TiO2 nanocomposites have been investigated. • Morphology and chemical composition of PSi/TiO2 nanocomposites were established. • Valence-band XPS maximums for PSi/TiO2 nanocomposites were found and analyzed. - Abstract: PSi/TiO2 nanocomposites fabricated by atomic layer deposition (ALD) and metal-assisted chemical etching (MACE) were investigated. The morphology and phase structure of PSi/TiO2 nanocomposites were studied by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM) with an energy dispersive X-ray spectroscopy (EDX) and Raman spectroscopy. The mean size of TiO2 nanocrystals was determined by TEM and Raman spectroscopy. X-ray photoelectron spectroscopy (XPS) was used to analyze the chemical elemental composition by observing the behavior of the Ti 2p, O 1s and Si 2p lines. TEM, Raman spectroscopy and XPS binding energy analysis confirmed the formation of TiO2 anatase phase inside the PSi matrix. The XPS valence band analysis was performed in order to investigate the modification of PSi/TiO2 nanocomposites electronic structure. Surface defects states of Ti3+ at PSi/TiO2 nanocomposites were identified by analyzing of XPS valence band spectra

  15. High performance GdBa{sub 2}Cu{sub 3}O{sub 7-z} film preparation by non-fluorine chemical solution deposition approach

    Energy Technology Data Exchange (ETDEWEB)

    Wang, W.T.; Pu, M.H.; Wang, W.W. [Key Laboratory of Magnetic Levitation and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Zhang, H. [Department of Physics, Peking University, Beijing 100871 (China); Cheng, C.H. [Key Laboratory of Magnetic Levitation and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China)] [Superconductivity Research Group, School of Materials Science and Engineering, University of New South Wale, Sydney, 2052 NSW (Australia); Zhao, Y., E-mail: yzhao@swjtu.edu.cn [Key Laboratory of Magnetic Levitation and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China)] [Superconductivity Research Group, School of Materials Science and Engineering, University of New South Wale, Sydney, 2052 NSW (Australia)

    2011-11-15

    Biaxially textured GdBa{sub 2}Cu{sub 3}O{sub 7}-z films with Tc above 93 K have been prepared on (0 0 l) by non-fluorine CSD approach. Nanoparticles with homogeneous distribution are introduced into the GdBCO films as effective pinning centers. A high Jc (77 K, 0 T) of 2.28 MA/cm{sup 2} with slow decreasing Jc-B behavior is observed in the films. Biaxially textured GdBa{sub 2}Cu{sub 3}O{sub 7-z} (GdBCO) films with T{sub c} above 93 K have been prepared on (0 0 l) LaAlO{sub 3} substrate by self-developed non-fluorine polymer-assisted chemical solution deposition (PA-CSD) approach. The GdBCO films show smooth and crack-free morphology. Many nanoscale particles with homogeneous distribution are observed in the GdBCO films, which have not been observed yet in the YBa{sub 2}Cu{sub 3}O{sub 7-z} (YBCO) films prepared by the same processing technique. Besides a high J{sub c} (77 K, 0 T) of 2.28 MA/cm{sup 2}, the optimized GdBCO films show a better J{sub c}-B behavior and an improved high-field J{sub c}, compared to the YBCO films.

  16. Preparation and characterization of Pd/Al2O3 and Pd nanoparticles as standardized test material for chemical and biochemical studies of traffic related emissions.

    Science.gov (United States)

    Leopold, K; Maier, M; Schuster, M

    2008-05-01

    Palladium model particles similar to those emitted from catalytic car exhaust converters were prepared and characterized with the intention of providing a standardized material for investigations of the chemical behavior and bioavailability of traffic related Pd emissions. Two series of Pd particles were prepared and characterized in detail: Pd nanoparticles (2-4 nm) dispersed on aluminum oxide particles of a diameter range between 0.1 to 30 microm and "Pd-only" nanoparticles of 5-10 nm in diameter. The Pd/alpha-Al2O3 particles are very similar to particles emitted from catalytic converters by mechanical abrasion. The Pd-only particles are useful e.g. for exposure studies in which the presence of aluminum could lead to interferences when studying biological and biochemical effects. The sample preparation procedure of both series was optimized in order to achieve elemental particles with proper sizes and a narrow size distribution. The obtained particles were characterized by transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), selective area diffraction (SAD), laser granulometry and graphite furnace atomic absorption spectrometry (GFAAS) for the measurement of Pd concentrations. PMID:18279916

  17. Preparation of activated carbons from olive-tree wood revisited. I. Chemical activation with H{sub 3}PO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Ould-Idriss, A.; Cuerda-Correa, E.M.; Fernandez-Gonzalez, C.; Alexandre-Franco, M.F.; Gomez-Serrano, V. [Extremadura Univ., Badajoz (Spain). Dept. of Organic and Inorganic Chemistry; Stitou, M. [Univ. Abdelmalek Esaadi, Tetouan (Morocco). Dept. de Chimie; Macias-Garcia, A. [Extremadura Univ., Badajoz (Spain). Dept. of Mechanical, Energetic and Materials Engineering

    2011-02-15

    In the conditioning tasks of olive-tree a large amount of a woody residue is generated. Such a residue has been traditionally used as a domestic fuel. In the last decades, however, this kind of use has lost importance and the preparation of activated carbons from olive-tree wood appears as an attractive alternative to valorize this by-product. In this study, the optimization of the chemical activation method with phosphoric acid for the production of activated carbon has been analyzed. The results obtained clearly show that samples prepared at 350 and 400 C exhibit a discrete porous development. On the contrary, when the carbonization temperature increases above 450 C the presence of a well-developed mesoporosity is observed. The mercury intrusion curves indicate that the samples exhibit a noticeably developed mesopore volume as well as a wide variety of mesopores ranging from 40 up to 1100 Aa of diameter. If the appropriate conditions are used, it is possible to prepare activated carbons showing tailored properties in terms of micro- or mesoporous texture and surface area. (author)

  18. PREPARATION OF CHEMICAL AND PHYSICAL CONJUGATES OF SELF-ASSEMBLING NANOPARTICLES WITH CELL-PENETRATING PEPTIDE AND DOXORUBICIN

    Directory of Open Access Journals (Sweden)

    Zhadyra Sagykyzy Shagyrova

    2015-09-01

    Full Text Available Abstract: Nano-sized carriers can help to reduce toxicity and improve clinical efficacy of drugs. Virus-like particles (VLPs are biocompatible and biodegradable self-assembling nanoparticles, which show great promise as carriers for substances for targeted delivery and controlled release. Either chemical conjugation of physical incorporation without formation of covalent bonds is possible to load substances of interest into VLPs.Objectives: To produce VLPs from recombinant viral capsid protein (HBcAg and test feasibility of methods of formation of chemical and physical conjugates of VLPs with substances of pharmacological interest.Methods: Virus-like particles composed from recombinant hepatitis B core antigen (HBcAg were produced by recombinant expression in E.coli and purified by successive centrifugation through sucrose gradients. Peptide transportan 10 was synthesized and used for carbodiimide (EDC-mediated conjugation to VLPs. Doxorubicin (DOX was loaded into the nucleic acid-containing VLPs to form physical conjugate.Results: VLPs with chemically attached moieties of cell-penetrating peptide transportan 10 were produced. The conjugate was examined in SDS-PAGE to confirm presence of conjugation products. Conjugation efficiency (molar ration peptide/protein in the conjugate reaches 0.5:1 (i.e. 50% of protein chains have one attached peptide moiety. The nucleic acid-containing VLPs can be loaded with the DOX forming stable non-covalent physical conjugate.Conclusion: Recombinantly expressed VLPs allow easy attaching of small molecules making them a convenient platform to develop drug carriers.

  19. Studies on the preparation of active oxygen-deficient copper ferrite and its application for hydrogen production through thermal chemical water splitting

    Institute of Scientific and Technical Information of China (English)

    YU Bo; ZHANG Ping; ZHANG Lei; CHEN Jing; XU JingMing

    2008-01-01

    Hydrogen generation through thermal chemical water splitting technology has recently received in-creasingly international interest in the nuclear hydrogen production field. Besides the main known sulfur-iodine (S-I) cycle developed by the General Atomics Company and the UT3 cycle (iron, calcium, and bromine) developed at the University of Tokyo, the thermal cycle based on metal oxide two-step water splitting methods is also receiving research and development attention worldwide. In this work, copper ferrite was prepared by the co-precipitation method and oxygen-deficient copper ferrite was synthesized through first and second calcination steps for the application of hydrogen production by a two-step water splitting process. The crystal structure, properties, chemical composition and δwere investigated in detail by utilizing X-ray diffraction (XRD), thermogravimetry (TG) and differential thermal analysis (DTA), atomic absorption spectrometer (AAS), ultraviolet spectrophotometry (UV), gas chro-matography (GC), and so on. The experimental two-step thermal chemical cycle reactor for hydrogen generation was designed and developed in this lab. The hydrogen generation process of water splitting through CuFe2O4-δ and the cycle performance of copper ferrite regeneration were firstly studied and discussed.

  20. Studies on the preparation of active oxygen-deficient copper ferrite and its application for hydrogen production through thermal chemical water splitting

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Hydrogen generation through thermal chemical water splitting technology has recently received in- creasingly international interest in the nuclear hydrogen production field. Besides the main known sulfur-iodine (S-I) cycle developed by the General Atomics Company and the UT3 cycle (iron, calcium, and bromine) developed at the University of Tokyo, the thermal cycle based on metal oxide two-step water splitting methods is also receiving research and development attention worldwide. In this work, copper ferrite was prepared by the co-precipitation method and oxygen-deficient copper ferrite was synthesized through first and second calcination steps for the application of hydrogen production by a two-step water splitting process. The crystal structure, properties, chemical composition and δ were investigated in detail by utilizing X-ray diffraction (XRD), thermogravimetry (TG) and differential thermal analysis (DTA), atomic absorption spectrometer (AAS), ultraviolet spectrophotometry (UV), gas chro- matography (GC), and so on. The experimental two-step thermal chemical cycle reactor for hydrogen generation was designed and developed in this lab. The hydrogen generation process of water splitting through CuFe2O4-δ and the cycle performance of copper ferrite regeneration were firstly studied and discussed.

  1. Preparation, Biodegradation of Coconut Oil Driven Chemically Modified Bovine Serum Albumin Microparticles of Encapsulated Cicer arietinum Amylase and Study of Their Application in Washing Detergents

    Directory of Open Access Journals (Sweden)

    Kirti Rani

    2014-10-01

    Full Text Available In present work, Cicer arietinum amylase was encapsulated by emulsification through covalent coupling by glutaraldehyde into chemically modified bovine serum albumin. Biodegradation of coconut oil driven emulsified bovine serum albumin encapsulated Cicer arietinum amylase was carried out by the alkaline protease for its controlled and sustained release of encapsulated enzyme from prepared microparticles of encapsulated Cicer arietinum amylase and its stability increased up to 6 months as compared to free enzyme. Its biodegradation was carried out by the using different concentration of alkaline protease (5U, 10U, 15U, 20U, 25U, 30U, 35U, 40U. Further, this coconut oil driven chemically modified bovine serum albumin microparticles of encapsulated Cicer arietinum amylase with alkaline protease were used with detergents for washing of stained cloths which have rust, gel pen ink, grease and chocolate strains. These chosen strains are very commonly present on uniforms of school going children which are very tough upon drying, hence, not to be easily vanish with well known brand detergents upon in one wash. But, the mixture solution of coconut oil driven chemically modified bovine serum albumin microparticles of encapsulated Cicer arietinum amylase along with alkaline protease were used with detergents powder for washing of these dry tough strains (rust, gel pen ink, grease and chocolate strains leads to vanishing these strains very fast with absolute clear results were found as compared to results of washing of stained cloths with detergents only.

  2. Preparation of conversion coating on Ti-6Al-4V alloy in mixed solution of phytic acid and ammonium fluoride through chemical modification

    Science.gov (United States)

    Li, Lanlan; He, Jian; Yang, Xu

    2016-05-01

    Conversion coatings on Ti-6Al-4V alloy was prepared through chemical modification in phytic acid and ammonium fluoride mixed solution. The influences of pH, time and the composition of solution on the microstructure of alloy surface were investigated. Scanning electron microscopy was used to observe the microstructure. The chemical composition of alloy surface before and after modification was investigated by energy dispersive X-ray spectroscopy. The results indicated that a conversion coating could be formed on the Ti-6Al-4V alloy in a mixed solution of phytic acid and ammonium fluoride, the growth and microstructure of the conversion coatings were critically dependent on the pH, time and concentration of phytic acid and ammonium fluoride. In 100 mg/ml phytic acid containing 125 mg/ml ammonium fluoride solution with a pH of 6, a compact conversion coating with the thickness of about 4.7 μm formed after 30 min immersion on Ti-6Al-4V alloy surface. The preliminary evaluation of bioactivity of conversion coating was performed by in vitro cell experiments. The results showed that this chemical modification method is a promising surface modification technique for Ti-6Al-4V alloy inplants.

  3. Effect of applied dc bias voltage on composition, chemical bonding and mechanical properties of carbon nitride films prepared by PECVD

    Institute of Scientific and Technical Information of China (English)

    LI Hong-xuan; XU Tao; HAO Jun-ying; CHEN Jian-min; ZHOU Hui-di; XUE Qun-ji; LIU Hui-wen

    2004-01-01

    Carbon nitride films were deposited on Si (100) substrates using plasma-enhanced chemical vapor deposition (PECVD) technique from CH4 and N2 at different applied dc bias voltage. The microstructure, composition and chemical bonding of the resulting films were characterized by Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The mechanical properties such as hardness and elastic modulus of the films were evaluated using nano-indentation. As the results, the Raman spectra, showing the G and D bands, indicate the amorphous structure of the films. XPS and FTIR measurements demonstrate the existence of various carbon-nitride bonds in the films and the hydrogenation of carbon nitride phase. The composition ratio of N to C, the nano-hardness and the elastic modulus of the carbon nitride films increase with increasing dc bias voltage and reach the maximums at a dc bias voltage of 300 V, then they decrease with further increase of the dc bias voltage. Moreover, the XRD analyses indicate that the carbon nitride film contains some polycrystalline C3N4 phase embedded in the amorphous matrix at optimized deposition condition of dc bias voltage of 300 V.

  4. Effect of gamma irradiation on microbial load, chemical and sensory properties of chicken kabab and sausage; as prepared chilled meals

    International Nuclear Information System (INIS)

    Chicken kabab and sausage were treated with 0, 2, 4 or 6 kGy doses of gamma irradiation in a 60CO package irradiator. Treated and untreated samples were kept in a refrigerator (1-4 degree centigrade). Microbiological, chemical and sensory characteristics of chicken kabab and sausage were evaluated at 0, 1, 2, 3, 4, and 5 months of storage. Proximate composition and sensory evaluation of the chicken kabab and sausage were also investigated, but only immediately after treatment. Irradiation did not influence the major constituents of chicken kabab and sausage (moisture, protein and fats). Gamma irradiation decreased the microbial load and increased the shelf-life of chicken kabab and sausage. The dose needed to decrease by 1 log cfu/g (D10 value) of Salmonella spp and E coli. numbers were 213 and 400 Gy in chicken kabab, while 345 and 250 Gy in chicken sausage, respectively. The chemical parameters, total acidity, volatile basic nitrogen (VBN), and thiobarbituric acid reactive substances (TBARS), which were chosen as the indices of freshness, were all well within the acceptable limit for up to 5 months for chicken kabab and sausage treated with 4 and 6 kGy. Sensory evaluation showed no significant differences between irradiated and non-irradiated samples. (author)

  5. XRD and XPS characterization of mixed valence Mn3O4 hausmannite thin films prepared by chemical spray pyrolysis technique

    International Nuclear Information System (INIS)

    Spray pyrolysis technique has been employed successfully for the synthesis of single phase mixed valence spinel hausmannite (Mn3O4) thin films using alcoholic start solution of manganese acetate (Mn(CH3COO)2.4H2O) on pyrex glass substrates at atmospheric pressure using air as a carrier gas. Thermal decomposition of the precursor in the temperature range 320-490 deg. C led to the formation of Mn3O4 phase as revealed from the thermogravimetry analysis. Prepared samples are characterized by X-ray diffraction that shows spinel structure with space group I41/amd. Pure and well crystallized specimen is subjected to X-ray photoelectron spectroscopy for the surface chemistry investigation of these systems at a molecular level. Surface Mn/O ratio is compared to the bulk composition of the sample. Atomic force micrographs revealed that the morphology and the surface grains of the films largely influenced by the substrate temperature.

  6. Optical properties of TiO{sub 2} thin films prepared by chemical spray pyrolysis from aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Ayouchi, R.; Casteleiro, C.; Schwarz, R. [Departamento de Fisica, Instituto Superior Tecnico, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal); Barrado, J.R.; Martin, F. [Laboratorio de Materiales y Superficie (Unidad Asociada al CSIC), Departamento de Fisica Aplicada I e Departamento de Ingenieria Quimica, Universidad de Malaga, 29071 Malaga (Spain)

    2010-04-15

    Titanium dioxide (TiO{sub 2}) is known to have three different kinds of polymorphous crystalline forms: rutile, anatase, and brookite. The rutile phase is always formed at higher temperatures, while the anatase phase is formed at lower temperatures and transformed into rutile phase above 800 C. Various deposition techniques have been developed for depositing TiO{sub 2} thin films, including evaporation, sputtering, chemical vapour deposition and thermal oxidation of titanium. Among them, the Chemical Spray Pyrolysis (CSP) technique has many advantages, such as good conformal coverage, the possibility of epitaxial growth and the application to large area deposition. Also, this method is low cost and it is easy to control the deposition growth parameters. In the present work, TiO{sub 2} thin films have been deposited on p-Si(001) and fused silica substrates by Chemical Spray Pyrolysis (CSP) method from aqueous solution containing titanium (IV) isopropoxide (Ti[OCH(CH{sub 3}){sub 2}]{sub 4}). As-deposited thin films show anatase polycrystalline structure, and rutile phase formed for films annealed at 750 C. SEM images have confirmed a smooth and crack-free surface with low surface roughness. X-ray photoelectron spectroscopy (XPS) combined with 4 keV Ar{sup +} depth profiling has shown that crystallized films correspond to TiO{sub 2}. Residual carbon coming from the organic precursor solution is only detected at the surface of the film. Thin films deposited on fused silica were highly transparent (more than 85%), with an indirect optical band gap of 3,43 and 3,33 eV for as-deposited and annealed films, respectively, and refractive indexes in the range between 2.01-2.29. Spectroscopic Ellipsometry (SE) also has been used to extract optical parameters. SE data fitted to triple-layer physical model revealed the same tendency to increase refractive index in annealed films. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  7. Raman Spectroscopic Study of Carbon Nanotubes Prepared Using Fe/ZnO-Palm Olein-Chemical Vapour Deposition

    Directory of Open Access Journals (Sweden)

    Syazwan Afif Mohd Zobir

    2012-01-01

    Full Text Available Multiwalled carbon nanotubes (MWCNTs were synthesized using Fe/ZnO catalyst by a dual-furnace thermal chemical vapor deposition (CVD method at 800–1000°C using nitrogen gas with a constant flow rate of 150 sccm/min as a gas carrier. Palm olein (PO, ferrocene in the presence of 0.05 M zinc nitrate, and a p-type silicon wafer were used as carbon source, catalyst precursor, and sample target, respectively. D, G, and G′ bands were observed at 1336–1364, 1559–1680, and 2667–2682 cm-1, respectively. Carbon nanotubes (CNTs with the highest degree of crystallinity were obtained at around 8000°C, and the smallest diameter of about 2 nm was deposited on the silicon substrate at 1000°C.

  8. Characterization of the ZnO thin film prepared by single source chemical vapor deposition under low vacuum condition

    Institute of Scientific and Technical Information of China (English)

    DENG; Hong(邓宏); B.; GONG; A.; J.; Petrella; J.; J.; Russell; R.; N.; Lamb

    2003-01-01

    A novel technique is developed for growing high quality ZnO thin films by means of single source chemical vapor deposition (SS CVD) under low vacuum conditions with the precursor of zinc carbamate Zn4O(CO2Net2)6. SEM, AFM and XRD studies show that the resultant thin films have high density, smooth surface, uniform polycrystalline structure and excellent c-axis orientation. XPS investigation indicates that the ZnO films are free of decomposed precursor residues in the bulk. Careful quantitative XPS analysis reveals that the ZnO films are stoichiometric with O/Zn atomic ratio very close to that of ZnO single crystal.

  9. Chemical fingerprinting and quantitative analysis of a Panax notoginseng preparation using HPLC-UV and HPLC-MS

    Directory of Open Access Journals (Sweden)

    Shao Qing

    2011-02-01

    Full Text Available Abstract Background Xuesaitong (XST injection, consisting of total saponins from Panax notoginseng, was widely used for the treatment of cardio- and cerebro-vascular diseases in China. This study develops a simple and global quality evaluation method for the quality control of XST. Methods High performance liquid chromatography-ultraviolet detection (HPLC-UV was used to identify and quantify the chromatographic fingerprints of the XST injection. Characteristic common peaks were identified using HPLC with photo diode array detection/electrospray ionization tandem mass spectrometry (HPLC-PDA/ESI-MSn. Results Representative fingerprints from ten batches of samples showed 27 'common saponins' all of which were identified and quantified using ten reference saponins. Conclusion Chemical fingerprinting and quantitative analysis identified most of the common saponins for the quality control of P. notoginseng products such as the XST injection.

  10. Structural, optical and photocatalytic properties of flower-like ZnO nanostructures prepared by a facile wet chemical method

    Directory of Open Access Journals (Sweden)

    Sini Kuriakose

    2013-11-01

    Full Text Available Flower-like ZnO nanostructures were synthesized by a facile wet chemical method. Structural, optical and photocatalytic properties of these nanostructures have been studied by X-ray diffraction (XRD, scanning electron microscopy (SEM, transmission electron microscopy (TEM, photoluminescence (PL and UV–vis absorption spectroscopy. SEM and TEM studies revealed flower-like structures consisting of nanosheets, formed due to oriented attachment of ZnO nanoparticles. Flower-like ZnO structures showed enhanced photocatalytic activity towards sun-light driven photodegradation of methylene blue dye (MB as compared to ZnO nanoparticles. XRD, UV–vis absorption, PL, FTIR and TEM studies revealed the formation of Zn(OH2 surface layer on ZnO nanostructures upon ageing. We demonstrate that the formation of a passivating Zn(OH2 surface layer on the ZnO nanostructures upon ageing deteriorates their efficiency to photocatalytically degrade of MB.

  11. Monolithically integrated InGaAs/InP MSM-FET photoreceiver prepared by chemical beam epitaxy

    International Nuclear Information System (INIS)

    The authors demonstrate the first monolithic integration of a metal-semiconductor-metal (MSM) InGaAs photodetector with an FET and resistors into a high-impedance front-end photoreceiver circuit. The sample was grown in a single step by chemical beam epitaxy, and standard processing steps for making FET's were used to fabricate the receiver circuit. Semi-insulating Fe-doped InP layers were used as the insulating gate of the FET, the barrier enhancement layer in the MSM photodetector, and the electrical isolation layer between the photodetector and the electronic circuit. A bit error rate of less than 10-9 at 200 Mbits/s has been achieved with this preliminary circuit for an optical power of - 17 dBm

  12. Preparation of chitosan/mesoporous silica nanoparticle composite hydrogels for sustained co-delivery of biomacromolecules and small chemical drugs

    Directory of Open Access Journals (Sweden)

    Min Zhu, Yufang Zhu, Lingxia Zhang and Jianlin Shi

    2013-01-01

    Full Text Available We have developed composite hydrogels of chitosan (CS and mesoporous silica nanoparticles (MSNs in this study. The gelation rate, gel strength, drug delivery behavior and chondrocyte proliferation properties were investigated. The introduction of MSNs into CS accelerated the gelation process at body temperature and also increased the elastic modulus G' from 1000 to 1800 Pa. When we used gentamicin (GS and bovine serum albumin (BSA as model small chemical drugs and biomacromolecules, respectively, the CS/MSN hydrogels released GS and BSA in a sustained manner simultaneously, but the CS hydrogels only showed sustained BSA release. Furthermore, in vitro chondrocyte culture showed that the CS/MSN composite hydrogels indeed performed much better in supporting chondrocyte growth and maintaining chondrocytic phenotype compared to the CS hydrogels. Therefore, the results suggest that the CS/MSN composite hydrogels can be potentially very useful for cartilage regeneration.

  13. Nanoscale multilayered and porous carbide interphases prepared by pressure-pulsed reactive chemical vapor deposition for ceramic matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Jacques, S., E-mail: jacques@lcts.u-bordeaux1.fr [LCTS, University of Bordeaux 1, CNRS, Herakles-Safran, CEA, 3 allee de la Boetie, F-33600 Pessac (France); Jouanny, I.; Ledain, O.; Maillé, L.; Weisbecker, P. [LCTS, University of Bordeaux 1, CNRS, Herakles-Safran, CEA, 3 allee de la Boetie, F-33600 Pessac (France)

    2013-06-15

    In Ceramic Matrix Composites (CMCs) reinforced by continuous fibers, a good toughness is achieved by adding a thin film called “interphase” between the fiber and the brittle matrix, which acts as a mechanical fuse by deflecting the matrix cracks. Pyrocarbon (PyC), with or without carbide sub-layers, is typically the material of choice to fulfill this role. The aim of this work was to study PyC-free nanoscale multilayered carbide coatings as interphases for CMCs. Nanoscale multilayered (SiC–TiC){sub n} interphases were deposited by pressure-Pulsed Chemical Vapor Deposition (P-CVD) on single filament Hi-Nicalon fibers and embedded in a SiC matrix sheath. The thicknesses of the carbide interphase sub-layers could be made as low as a few nanometers as evidenced by scanning and transmission electron microscopy. By using the P-ReactiveCVD method (P-RCVD), in which the TiC growth involves consumption of SiC, it was not only possible to obtain multilayered (SiC–TiC){sub n} films but also TiC films with a porous multilayered microstructure as a result of the Kirkendall effect. The porosity in the TiC sequences was found to be enhanced when some PyC was added to SiC prior to total RCVD consumption. Because the porosity volume fraction was still not high enough, the role of mechanical fuse of the interphases could not be evidenced from the tensile curves, which remained fully linear even when chemical attack of the fiber surface was avoided.

  14. Characterisation of samarium and nitrogen co-doped TiO2 films prepared by chemical spray pyrolysis

    International Nuclear Information System (INIS)

    Highlights: ► The TiO2:N:Sm thin films deposited by chemical spray pyrolysis have anatase structure. ► According to XPS, N is incorporated into the TiO2 matrix. ► N-doping increases and Sm-doping reduces the crystallite size of the TiO2:N:Sm films. ► Incorporation of N strongly suppresses the Sm3+ PL emission. - Abstract: The sol–gel chemical spray pyrolysis method was used to deposit samarium and nitrogen co-doped TiO2 films onto a quartz substrate at a growth temperature of 450 °C using pulsed spray solution feed, followed by annealing at 500 °C for 2 h in air. The obtained films exhibited anatase structure independent of the doping level. According to XRD analysis, the mean crystallite size of the undoped TiO2, TiO2:N(25) and TiO2:N(5):Sm(5) films was 32, 38 and 20 nm, respectively. According to AFM, the undoped TiO2 film consisted of agglomerates with a size of 30–200 nm. N-doping (25 at%) transformed the agglomerates into individually distinctive grains with a size of ca. 30 nm, while Sm doping (5 at%) caused a significant decrease in the average diameter of the agglomerates to ca. 100 nm. The RMS roughness of the undoped TiO2 film was 1.7 nm; doping resulted in the formation of smoother films with RMS roughness of 0.9–1.4 nm. XPS data indicated that the Sm and N dopants were incorporated into the TiO2 crystal lattice and/or adsorbed on the surface of the film. An increasing nitrogen concentration in the spray solution correlates to a systematic suppressing of the photoluminescence intensity of Sm3+.

  15. Preparation and use of chemically modified MCM-41 and silica gel as selective adsorbents for Hg(II) ions

    International Nuclear Information System (INIS)

    Adsorbents for Hg(II) ion extraction were prepared using amorphous silica gel and ordered MCM-41. Grafting with 2-(3-(2-aminoethylthio)propylthio)ethanamine was used to functionalize the silica. The functionalized adsorbents were characterized by nitrogen adsorption, X-ray diffraction, 13C MAS NMR spectroscopy and thermogravimetric analysis. The adsorption properties of the modified silica gel and MCM-41 were compared using batch method. The effect of pH, stirring time, ionic strength and foreign ions were studied. The extraction of Hg(II) ions occurred rapidly with the modified MCM-41 and the optimal pH range for the extraction by the modified materials was pH 4-7. Foreign ions, especially Cl- had some effect on the extraction efficiency of the modified silica gel and the modified MCM-41. The adsorption behavior of both adsorbents could be described by a Langmuir model at 298 K, and the maximum adsorption capacity of the modified silica gel and MCM-41 at pH 3 was 0.79 and 0.70 mmol g-1, respectively. The modified MCM-41 showed a larger Langmuir constant than that of the modified silica gel, indicating a better ability for Hg(II) ion adsorption. The results indicate that the structure of the materials affects the adsorption behavior. These materials show a potential for the application as effective and selective adsorbents for Hg(II) removal from water

  16. Sensory and physico-chemical characteristics of desserts prepared with egg products processed by freeze and spray drying

    Directory of Open Access Journals (Sweden)

    Marcelo Nunes de Jesús

    2013-09-01

    Full Text Available In this work, three freeze-dried (FD egg products (whole egg (WE, egg yolk (EY and egg white (EW were obtained and the acceptability of confections prepared with each was evaluated. Sensory analyses for confections were performed by hedonic testing with fifty panelists in each evaluation. The studied confections were: Condensed Milk Pudding (P, Quindim (Q and Meringue (M. The results obtained for confections made with FD egg products were compared with the achieved through other formulations of the same desserts made with fresh (F or spray-dried (SD egg products. The sensory analysis results for confections made with FD egg products showed good acceptance by panelists. A principal component analysis of the sensory evaluation data was carried out to identify similarities between the different egg products. The PCA supported the conclusion that FD egg products can substitute their fresh and SD counterparts in dessert formulations with good acceptability while keeping the advantages conferred by the freeze-drying method.

  17. Development of preparative and analytical methods of the hop bitter acid oxide fraction and chemical properties of its components.

    Science.gov (United States)

    Taniguchi, Yoshimasa; Matsukura, Yasuko; Taniguchi, Harumi; Koizumi, Hideki; Katayama, Mikio

    2015-01-01

    The bitter acids in hops (Humulus lupulus L.) and beer, such as α-, β-, and iso-α-acids, are known to affect beer quality and display various physiological effects. However, these compounds readily oxidize, and the effect of the oxides on the properties of beer or their potential health benefits are not well understood. In this study, we developed a simple preparative method for the bitter acid oxide fraction derived from hops and designated the constituents as matured hop bitter acids (MHBA). HPLC-PDA-ESI/HRMS and MS(2) revealed that MHBA are primarily composed of α-acid-derived oxides, which possess a common β-tricarbonyl moiety in their structures similar to α-, β-, and iso-α-acids. We also developed a quantitative analytical method of whole MHBA by HPLC, which showed high precision and reproducibility. Using our newly developed method, the concentration of whole MHBA in several commercial beers was evaluated. Our results will promote the study of bitter acid oxides. PMID:25996959

  18. Preparation of carbonaceous adsorbents from sewage sludge by chemical activation process - application to air and water treatments

    Energy Technology Data Exchange (ETDEWEB)

    Rio, S.; Le Coq, L.; Faur-Brasquet, C.; Le Cloirec, P. [Ecole des Mines de Nantes (UMR CNRS 6144 GEPEA), 44 - Nantes (France)

    2004-07-01

    Wastewater treatment plants produce considerable amounts of liquid waste material called sewage sludge. In France, sewage sludge production is about 950,000 tons of dried matter per year. The traditional ways of sludge valorization include farmland application, landfill and incineration. But, with some traditional disposal ways coming under pressure like farmland applications and others being phased out like landfill, it is necessary to seek cost - effective and innovative solutions to sewage sludge disposal problem. Today, one promising approach for production of cheap and efficient carbonaceous sorbent is the use of sewage sludge. This study aims to investigate the effect of sulfuric acid activation conditions on physico-chemical and adsorptive properties of the carbonaceous sorbents made from viscous liquid sludge collected at municipal wastewater treatment plant of Nantes, in France. Chemical activation by sulfuric acid is carried out using an impregnation method. Dried viscous liquid sludge is mixed with H{sub 2}SO{sub 4} solutions for 6 h. The resulting mixture is filtered and dried at 105 C. Then, impregnated sludge is activated in a horizontal furnace under nitrogen atmosphere. The effects of impregnation ratio (0.5 - 1.5 gH{sub 2}SO{sub 4}g{sup -1} sludge), temperature (600-800 C) and time (60-180 minutes) are studied using experimental design methodology. The physico-chemical properties of the resulting sorbents are determined using various characterization techniques: - Elemental analysis, determination of surface functional groups by the Boehm method, surface pH measurement and Point of Zero Charge (pH{sub pzc}) enable a complete characterization of the surface chemistry, - BET analyzer allows specific surface area and the meso-porosity and micro-porosity to be determined. Finally, Adsorption properties are determined during copper ion, dyes (Acid Red 18 and Basic Violet 4) and phenol removal experiments in aqueous solution as well as VOC in gas phase

  19. Preparation of high-quality hydrogenated amorphous silicon film with a new microwave electron cyclotron resonance chemical vapour deposition system assisted with hot wire

    Institute of Scientific and Technical Information of China (English)

    Zhu Xiu-Hong; Chen Guang-Hua; Yin Sheng-Yi; Rong Yan-Dong; Zhang Wen-Li; Hu Yue-Hui

    2005-01-01

    The preparation of high-quality hydrogenated amorphous silicon (a-Si:H) film with a new microwave electron cyclotron resonance-chemical vapour deposition (MWECR-CVD) system assisted with hot wire is presented. In this system the hot wire plays an important role in perfecting the microstructure as well as improving the stability and the optoelectronic properties of the a-Si:H film. The experimental results indicate that in the microstructure of the a-Si:H film, the concentration of dihydride is decreased and a trace of microcrystalline occurs, which is useful to improve its stability, and that in the optoelectronic properties of the a-Si:H film, the deposition rate reaches above 2.0nm/s and the photosensitivity increases up to 4.71× 105.

  20. One-step green synthetic approach for the preparation of multicolor emitting copper nanoclusters and their applications in chemical species sensing and bioimaging.

    Science.gov (United States)

    Bhamore, Jigna R; Jha, Sanjay; Mungara, Anil Kumar; Singhal, Rakesh Kumar; Sonkeshariya, Dhanshri; Kailasa, Suresh Kumar

    2016-06-15

    One-step green microwave synthetic approach was developed for the synthesis of copper nanoclusters (Cu NCs) and used as a fluorescent probe for the sensitive detection of thiram and paraquat in water and food samples. Unexpectedly, the prepared Cu NCs exhibited strong orange fluorescence and showed emission peak at 600 nm, respectively. Under optimized conditions, the quenching of Cu NCs emission peak at 600 nm was linearly proportional to thiram and paraquat concentrations in the ranges from 0.5 to 1000 µM, and from 0.2 to 1000 µM, with detection limits of 70 nM and 49 nM, respectively. In addition, bioimaging studies against Bacillus subtilis through confocal fluorescence microscopy indicated that Cu NCs showed strong blue and green fluorescence signals, good permeability and minimum toxicity against the various bacteria species, which demonstrates their potential feasibility for chemical species sensing and bioimaging applications. PMID:26851582

  1. Preparation of Aligned Ultra-long and Diameter-controlled Silicon Oxide Nanotubes by Plasma Enhanced Chemical Vapor Deposition Using Electrospun PVP Nanofiber Template

    Science.gov (United States)

    Zhou, Ming; Zhou, Jinyuan; Li, Ruishan; Xie, Erqing

    2010-02-01

    Well-aligned and suspended polyvinyl pyrrolidone (PVP) nanofibers with 8 mm in length were obtained by electrospinning. Using the aligned suspended PVP nanofibers array as template, aligned ultra-long silicon oxide (SiO x) nanotubes with very high aspect ratios have been prepared by plasma-enhanced chemical vapor deposition (PECVD) process. The inner diameter (20-200 nm) and wall thickness (12-90 nm) of tubes were controlled, respectively, by baking the electrospun nanofibers and by coating time without sacrificing the orientation degree and the length of arrays. The micro-PL spectrum of SiO x nanotubes shows a strong blue-green emission with a peak at about 514 nm accompanied by two shoulders around 415 and 624 nm. The blue-green emission is caused by the defects in the nanotubes.

  2. Response Behaviour of a Hydrogen Sensor Based on IonicConducting Polymer-metal Interfaces Prepared by the ChemicalReduction Method

    Directory of Open Access Journals (Sweden)

    Werner Weppner

    2006-04-01

    Full Text Available A solid-state amperometric hydrogen sensor based on a protonated Nafionmembrane and catalytic active electrode operating at room temperature was fabricated andtested. Ionic conducting polymer-metal electrode interfaces were prepared chemically byusing the impregnation-reduction method. The polymer membrane was impregnated withtetra-ammine platinum chloride hydrate and the metal ions were subsequently reduced byusing either sodium tetrahydroborate or potassium tetrahydroborate. The hydrogen sensingcharacteristics with air as reference gas is reported. The sensors were capable of detectinghydrogen concentrations from 10 ppm to 10% in nitrogen. The response time was in therange of 10-30 s and a stable linear current output was observed. The thin Pt films werecharacterized by XRD, Infrared Spectroscopy, Optical Microscopy, Atomic ForceMicroscopy, Scanning Electron Microscopy and EDAX.

  3. Tribological and thermal stability study of nanoporous amorphous boron carbide films prepared by pulsed plasma chemical vapor deposition

    Science.gov (United States)

    Liza, Shahira; Ohtake, Naoto; Akasaka, Hiroki; Munoz-Guijosa, Juan M.

    2015-06-01

    In this work, the thermal stability and the oxidation and tribological behavior of nanoporous a-BC:H films are studied and compared with those in conventional diamond-like carbon (DLC) films. a-BC:H films were deposited by pulsed plasma chemical vapor deposition using B(CH3)3 gas as the boron source. A DLC interlayer was used to prevent the a-BC:H film delamination produced by oxidation. Thermal stability of a-BC:H films, with no delamination signs after annealing at 500 °C for 1 h, is better than that of the DLC films, which completely disappeared under the same conditions. Tribological test results indicate that the a-BC:H films, even with lower nanoindentation hardness than the DLC films, show an excellent boundary oil lubricated behavior, with lower friction coefficient and reduce the wear rate of counter materials than those on the DLC film. The good materials properties such as low modulus of elasticity and the formation of micropores from the original nanopores during boundary regimes explain this better performance. Results show that porous a-BC:H films may be an alternative for segmented DLC films in applications where severe tribological conditions and complex shapes exist, so surface patterning is unfeasible.

  4. Chemically prepared silver electrode for determination of N-acetyl-L-cysteine by flow-injection potentiometry.

    Science.gov (United States)

    Kolar, M; Dobcnik, D

    2003-01-01

    This paper describes the use of the silver electrode by means of chemical pretreatment of the electrode surface with mercuric(II) chloride solution and potassium iodide solution in flow injection analysis (FIA). The electrode is used as a potentiometric sensor for the indirect determination of NAC in a carrier stream containing iodine. A one-channel flow system that consists of a peristaltic pump, injection valve, a silver wire electrode and a saturated calomel reference electrode (SCE) was used. Some typical FIA parameters such as flow rate, tube length and composition of the carrier stream were varied. The electrode is further characterised by a constant linear response within the concentration range for NAC between 4.0 x 10(-6) and 1.0 x 10(-3) M at the slope of 60.6 +/- 1.0 mV/p(NAC). Some pharmaceutical products containing NAC were also tested. These results can be compared to the results obtained by the direct potentiometric titrations with silver nitrate and are also in good agreement with values declared by pharmaceutical manufacturers.

  5. Preparation of ZrC nano-particles reinforced amorphous carbon composite coating by atmospheric pressure chemical vapor deposition

    International Nuclear Information System (INIS)

    To eliminate cracks caused by thermal expansion mismatch between ZrC coating and carbon-carbon composites, a kind of ZrC/C composite coating was designed as an interlayer. The atmospheric pressure chemical vapor deposition was used as a method to achieve co-deposition of ZrC and C from ZrCl4-C3H6-H2-Ar source. Zirconium tetrachloride (ZrCl4) powder carrier was especially made to control accurately the flow rate. The microstructure of ZrC/C composite coating was studied using analytical techniques. ZrC/C coating shows same morphology as pyrolytic carbon. Transmission electron microscopy (TEM) shows ZrC grains with size of 10-50 nm embed in turbostratic carbon. The formation mechanism is that the growth of ZrC crystals was inhibited by surrounding pyrolytic carbon and kept as nano-particles. Fracture morphologies imply good combination between coating and substrate. The ZrC crystals have stoichiometric proportion near 1, with good crystalline but no clear preferred orientation while pyrolytic carbon is amorphous. The heating-up oxidation of ZrC/C coating shows 11.58 wt.% loss. It can be calculated that the coating consists of 74.04 wt.% ZrC and 25.96 wt.% pyrolytic carbon. The average density of the composite coating is 5.892 g/cm3 by Archimedes' principle.

  6. Vertically aligned Si nanocrystals embedded in amorphous Si matrix prepared by inductively coupled plasma chemical vapor deposition (ICP-CVD)

    International Nuclear Information System (INIS)

    Highlights: • Inductively-coupled plasma is used for nanostructured silicon at room temperature. • Low temperature deposition allows device processing on various substrates. • Deposition pressure is the most effective parameter in controlling nanostructure. • Films consist of quantum dots in a-Si matrix and exhibit columnar vertical growth. • Films are porous to oxygen infusion along columnar grain boundaries. - Abstract: Vertically-aligned nanostructured silicon films are deposited at room temperature on p-type silicon wafers and glass substrates by inductively-coupled, plasma-enhanced chemical vapor deposition (ICPCVD). The nanocrystalline phase is achieved by reducing pressure and increasing RF power. The crystalline volume fraction (Xc) and the size of the nanocrystals increase with decreasing pressure at constant power. Columnar growth of nc-Si:H films is observed by high resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM). The films exhibit cauliflower-like structures with high porosity that leads to slow but uniform oxidation after exposure to air at room temperature. Films deposited at low pressures exhibit photoluminescence (PL) signals that may be deconvoluted into three distinct Gaussian components: 760–810, 920–935, and 990–1000 nm attributable to the quantum confinement and interface defect states. Hydrogen dilution is manifested in significant enhancement of the PL, but it has little effect on the nanocrystal size and Xc

  7. Morphological alteration and exceptional magnetic properties of air-stable FeCo nanocubes prepared by a chemical reduction method

    Energy Technology Data Exchange (ETDEWEB)

    Chokprasombat, K., E-mail: komkrich28@gmail.com [School of Physics, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 30000 (Thailand); Harding, P. [Molecular Technology Research Unit, School of Science, Walailak University, Nakhon Si Thammarat 80161 (Thailand); Pinitsoontorn, S. [Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002 (Thailand); Maensiri, S. [School of Physics, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 30000 (Thailand)

    2014-11-15

    FeCo nanocubes are of great interest due to their outstanding magnetic properties and larger contact area compared to the spherical particles. Herein, the FeCo nanocubes could be obtained by the reduction of metal ions by hydrazine hydrate under a concentrated basic condition. It was found that shape of the FeCo nanocubes varied from cubic with a mean edge length of 130±3 nm to polyhedron (diameter around 500–700 nm) depending on the concentration of using polymer. A lot of irregular nanoplates were also obtained when used the excessive polymer. In addition, the as-synthesized particles were air-stable which might be related to the formation of thin polymer shells on particle surfaces. The FeCo nanocubes also possessed exceptional magnetic properties at room temperature, including a very high saturation magnetization (217.14 emu/g) and low coercivity (85.95 Oe). - Highlights: • We report the synthesis of FeCo nanocubes by a chemical reduction method. • Shape of the particles clearly depended on the amount of polymer used. • The particles were air-stable and possessed excellent magnetic properties.

  8. Effect of Preparation and Storage Conditions on Physical and Chemical Properties of Puree, Puree Juices and Cloudy Juices Obtained from Pumpkin with Added Japanese Quince and Strawberries

    Directory of Open Access Journals (Sweden)

    Agnieszka NAWIRSKA-OLSZAŃSKA

    2016-06-01

    Full Text Available When evaluated in terms of taste, smell or active ingredients, pumpkin in itself is not very attractive as a raw material. Hence it seems recommendable to blend pumpkin with other fruits. The pumpkin chosen for the experiments was of the variety ‘Karowita’. The aim of the study was to compare the physical and chemical properties of pumpkin samples based on different storage conditions. Pumpkin puree, puree juice and cloudy juices containing Japanese quince and strawberries were evaluated for their physical and chemical properties initially and after three months storage at temperatures of 4 °C and 30 °C. Cloudy juices were prepared with pectolytic preparation. The extract dry matter in all the samples was at a similar level. Puree and puree juice had considerably higher viscosity than cloudy juices. The highest quantities of bioactive compounds were detected in slightly processed samples (puree, puree juice and cloudy juices stored at 4 °C. Increased content of polyphenols was observed in puree and puree juice after storage. However, in the remaining samples, there was observed a decrease in the content of the compounds. A considerable decrease in carotenoids took place in samples subjected to pressing, where the amount of assayed carotenoids in puree was 5.24 mg/100 g fresh matter (FM, 4.15 mg/100 g FM in puree juice, and 0.18-0.47 mg/100 g FM in cloudy juices. The pressing also caused a significant decrease in colour parameters. Three months of storage showed markedly decreased contents of carotenoids and vitamin C.

  9. Preparation of highly photocatalytic active CdS/TiO{sub 2} nanocomposites by combining chemical bath deposition and microwave-assisted hydrothermal synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Li, Li, E-mail: qqhrll@163.com [College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China); Key Laboratory of Composite Modified Material of Colleges in Heilongjiang Province, Qiqihar 161006 (China); Wang, Lili [College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China); Hu, Tianyu [College of Environment and Resources, Jilin University, Changchun 130024 (China); Zhang, Wenzhi; Zhang, Xiuli; Chen, Xi [College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China)

    2014-10-15

    CdS/TiO{sub 2} nanocomposites were prepared from Cd and Ti (1:1 M ratio) using cetyltrimethylammonium bromide by a two-step chemical bath deposition (CBD) and microwave-assisted hydrothermal synthesis (MAHS) method. A series of nanocomposites with different morphologies and activities were prepared by varying the reaction time in the MAHS (2, 4, and 6 h). The crystal structure, morphology, and surface physicochemical properties of the nanocomposites were characterized by X-ray diffraction, UV–visible diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and N{sub 2} adsorption–desorption measurements. The results show that the CdS/TiO{sub 2} nanocomposites were composed of anatase TiO{sub 2} and hexagonal CdS phases with strong absorption in the visible region. The surface morphologies changed slightly with increasing microwave irradiation time, while the Brunauer–Emmett–Teller surface area increased remarkably. The photocatalytic degradation of methyl orange (MO) was investigated under UV light and simulated sunlight irradiation. The photocatalytic activity of the CdS/TiO{sub 2} (6 h) composites prepared by the MAHS method was higher than those of CdS, P25, and other CdS/TiO{sub 2} nanocomposites. The CdS/TiO{sub 2} (6 h) nanocomposites significantly affected the UV and microwave-assisted photocatalytic degradation of different dyes. To elucidate the photocatalytic reaction mechanism for the CdS/TiO{sub 2} nanocomposites, controlled experiments were performed by adding different radical scavengers. - Graphical abstract: CdS/TiO{sub 2} nanocomposites were prepared using CTAB by CBD combined with MAHS method. In addition, with increasing microwave irradiation time, the morphology of CdS/TiO{sub 2} changed from popcorn-like to wedge-like structure. - Highlights: • The CdS/TiO{sub 2} was prepared by CBD combined with MAHS two-step method under CTAB. • The morphologies of as-samples were different with the time of

  10. Preparation of highly photocatalytic active CdS/TiO2 nanocomposites by combining chemical bath deposition and microwave-assisted hydrothermal synthesis

    International Nuclear Information System (INIS)

    CdS/TiO2 nanocomposites were prepared from Cd and Ti (1:1 M ratio) using cetyltrimethylammonium bromide by a two-step chemical bath deposition (CBD) and microwave-assisted hydrothermal synthesis (MAHS) method. A series of nanocomposites with different morphologies and activities were prepared by varying the reaction time in the MAHS (2, 4, and 6 h). The crystal structure, morphology, and surface physicochemical properties of the nanocomposites were characterized by X-ray diffraction, UV–visible diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and N2 adsorption–desorption measurements. The results show that the CdS/TiO2 nanocomposites were composed of anatase TiO2 and hexagonal CdS phases with strong absorption in the visible region. The surface morphologies changed slightly with increasing microwave irradiation time, while the Brunauer–Emmett–Teller surface area increased remarkably. The photocatalytic degradation of methyl orange (MO) was investigated under UV light and simulated sunlight irradiation. The photocatalytic activity of the CdS/TiO2 (6 h) composites prepared by the MAHS method was higher than those of CdS, P25, and other CdS/TiO2 nanocomposites. The CdS/TiO2 (6 h) nanocomposites significantly affected the UV and microwave-assisted photocatalytic degradation of different dyes. To elucidate the photocatalytic reaction mechanism for the CdS/TiO2 nanocomposites, controlled experiments were performed by adding different radical scavengers. - Graphical abstract: CdS/TiO2 nanocomposites were prepared using CTAB by CBD combined with MAHS method. In addition, with increasing microwave irradiation time, the morphology of CdS/TiO2 changed from popcorn-like to wedge-like structure. - Highlights: • The CdS/TiO2 was prepared by CBD combined with MAHS two-step method under CTAB. • The morphologies of as-samples were different with the time of microwave increased. • Compared with TiO2, as-samples show

  11. Physico-chemical properties investigation of cisplatin loaded polybutyladipate (PBA) nanoparticles prepared by w/o/w

    Energy Technology Data Exchange (ETDEWEB)

    Khoee, Sepideh, E-mail: Khoee@khayam.ut.ac.ir [Polymer Chemistry Department, School of Science, University of Tehran, P.O. Box 14155-6455, Tehran (Iran, Islamic Republic of); Sattari, Ahmad [Polymer Chemistry Department, School of Science, University of Tehran, P.O. Box 14155-6455, Tehran (Iran, Islamic Republic of); Atyabi, Fatemeh [Novel Drug Delivery Systems Lab, Faculty of Pharmacy, Medical Sciences/University of Tehran, Tehran P.O. Box 14155-6451 (Iran, Islamic Republic of)

    2012-07-01

    cis-Diamminedichloroplatinum(II) (cisplatin) is used against different kinds of cancers. Unfortunately, because of the severe side-effects like nephrotoxicity, ototoxicity, etc., they are administered in small doses at low concentrations. The purpose of this work is to improve injectional controlled release (ICR) of cisplatin that releases drug in the extended temporal periods. In order to access this aim, biodegradable polymeric nanoparticles containing cisplatin as anticancer drug of various ranges from 71 to 661 nm were prepared by a w/o/w double emulsion solvent evaporation technique. Influences of process parameters such as solvent removal technique, type and concentration of polymer, volume of oil phase, volume of external aqueous phase, concentration of stabilizer, drug concentration in the internal and external aqueous phases and power of sonication on morphology, characteristics of the nanoparticles and release profile were investigated. Morphology of the nanoparticles was studied by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) and the images indicated that spherical shape of the nanoparticles can be tailored to rod-like shape by changing the reaction parameters. Size of the nanoparticles decreased as polymer concentration decreases. Volume of oil phase, power of sonication and drug concentration in the internal water phase affected the size of nanoparticles. Drug release profiles indicate that polymer concentration in the oil phase and stabilizer concentration in the external water phase have critical role in the drug release process from the nanoparticles. The in-vitro release of the encapsulated drug was observed by using the diffusion models of release from a sphere carrier and the release pattern was shown to be a complex process.

  12. Physico-chemical properties investigation of cisplatin loaded polybutyladipate (PBA) nanoparticles prepared by w/o/w

    International Nuclear Information System (INIS)

    cis-Diamminedichloroplatinum(II) (cisplatin) is used against different kinds of cancers. Unfortunately, because of the severe side-effects like nephrotoxicity, ototoxicity, etc., they are administered in small doses at low concentrations. The purpose of this work is to improve injectional controlled release (ICR) of cisplatin that releases drug in the extended temporal periods. In order to access this aim, biodegradable polymeric nanoparticles containing cisplatin as anticancer drug of various ranges from 71 to 661 nm were prepared by a w/o/w double emulsion solvent evaporation technique. Influences of process parameters such as solvent removal technique, type and concentration of polymer, volume of oil phase, volume of external aqueous phase, concentration of stabilizer, drug concentration in the internal and external aqueous phases and power of sonication on morphology, characteristics of the nanoparticles and release profile were investigated. Morphology of the nanoparticles was studied by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) and the images indicated that spherical shape of the nanoparticles can be tailored to rod-like shape by changing the reaction parameters. Size of the nanoparticles decreased as polymer concentration decreases. Volume of oil phase, power of sonication and drug concentration in the internal water phase affected the size of nanoparticles. Drug release profiles indicate that polymer concentration in the oil phase and stabilizer concentration in the external water phase have critical role in the drug release process from the nanoparticles. The in-vitro release of the encapsulated drug was observed by using the diffusion models of release from a sphere carrier and the release pattern was shown to be a complex process.

  13. The Synthesis of Anatase Nanoparticles and the Preparation of Photocatalytically Active Coatings Based on Wet Chemical Methods for Self-Cleaning Applications

    Directory of Open Access Journals (Sweden)

    Dejan Verhovšek

    2012-01-01

    Full Text Available We report on an improved sol-gel method for the production of highly photocatalytic titanium dioxide (TiO2 anatase nanoparticles which can provide appropriate control over the final characteristics of the nanoparticles, such as particle size, crystallinity, crystal structure, morphology, and also the degree of agglomeration. The synthesized anatase nanoparticles were characterized using various techniques, such as X-ray powder diffraction (XRD, scanning electron microscopy (SEM, and transmission electron microscopy (TEM, and were tested in coatings for self-cleaning glass and ceramic surfaces. The coatings were prepared using a soft chemistry route and are completely transparent to visible light and exhibit a high photocatalytic effect, which was determined by contact-angle measurements. Finally, it is worth mentioning that both the sol-gel synthesis method and the coating-preparation method are based on a wet chemical process, thus presenting no risk of handling the TiO2 anatase nanoparticles in their potentially hazardous powder form at any stage of our development. Low-price, easy-to-handle, and nontoxic materials were used. Therefore, our work represents an important contribution to the development of TiO2 anatase nanoparticle coatings that provide a high photocatalytic effect and can thus be used for numerous applications.

  14. The effect of thermal annealing on the optical band gap of cadmium sulphide thin films, prepared by the chemical bath deposition technique

    International Nuclear Information System (INIS)

    Cadmium sulphide thin films have been prepared by the chemical bath deposition technique (ph 11, 70 degree centigrade). Two different sets of films were prepared under varied conditions and concentrations of their ions sources (Cd2+ from cadmium nitrate, S2- from thiourea) and Na2EDTA as a complexing agent. A UV mini-Schimazu UV-VIS Spectrophotometer was used to determine the optical absorbance of the films as a function of wavelength at room temperature over the wavelength range 200 - 600 nm. The samples were then thermally annealed for thirty minutes, at temperatures of 100 degree centigrade, and 200 degree centigrade, after which the absorbance of the films were again recorded. The band gap values obtained for the sample with 0.5 M CdS as deposited, annealed at 100 degree centigrade and 200 degree centigrade were 2.1 eV, 2.2 eV and 2.3 eV respectively. Whilst the values obtained for the sample 0.15 CdS as deposited, annealed at 100 degree centigrade and annealed at 200 degree centigrade were 2.0 eV, 2.01 eV and 2.02 eV respectively. The increase in band gap with annealing temperature might be attributed to the improvement in crystallinity in the films. (au)

  15. Effect of glass tempering on microstructure and functional properties of SnO2:F thin film prepared by atmosphere pressure chemical vapor deposition

    International Nuclear Information System (INIS)

    The low-emission glass was prepared via depositing fluorine-doped tin oxide thin film on glass substrate by atmospheric pressure chemical vapor deposition method. The as-deposited low-emission glass was found to present a SnO2:F/SiCxOy/glass sandwich structure via focused ion beam technique and transmission microscopic measurement. After tempering process at ∼ 650 °C with varied periods, the electrical and optical properties of the SnO2:F thin film remained stable for less than 10 min, but decreased dramatically when the tempering period exceeded 10 min, which was mainly due to the oxygen chemisorptions and fluorine ion diffusion. It was observed that the SnO2:F thin films presented uniform polycrystalline nature of cassiterite structure throughout the tempering process. The study has therefore suggested the appropriate tempering conditions for the SnO2:F low-emission glass, and provided a critical guidance for further energy-saving glass applications. - Highlights: • The sandwich structural low-e glass was prepared on an industrial line. • The film showed stable morphology and functional property under low temperature. • The functional property decreased dramatically after long time tempering at 650 °C

  16. Fibrous TiO2 prepared by chemical vapor deposition using activated carbon fibers as template via adsorption, hydrolysis and calcinations

    Institute of Scientific and Technical Information of China (English)

    Hui-na YANG; Li-fen LIU; Feng-lin YANG; Jimmy C. YU

    2008-01-01

    TiO2 fibers were prepared via alternatively introducing water vapor and Ti precursor carried by Ne to an APCVD (chemical vapor deposition under atmospheric pressure) reactor at <200 ℃. Activated carbon fibers (ACFs) were used as templates for deposition and later removed by calcinations. The obtained catalysts were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brtmauer, Emmett and Teller (BET) and X-ray diffraction (XRD) analysisThe pores within TiO2 fibers included micro-range and meso-range, e.g., 7 nm, and the specific surface areas for TiO2 fibers were 141 m2/g and 148 m2/g for samples deposited at 100 ℃ and 200 ℃ (using ACF1700 as template), respectively. The deposition temperature significantly influenced TiO2 morphology. The special advantages of this technique for preparing porous nano-material include no consumption of organic solvent in the process and easy control of deposition conditions and speeds.

  17. Preparation of Chitosan from Brine Shrimp (Artemia urmiana Cyst Shells and Effects of Different Chemical Processing Sequences on the Physicochemical and Functional Properties of the Product

    Directory of Open Access Journals (Sweden)

    Farnood Shokouhi Sabet Jalali

    2008-06-01

    Full Text Available Chitosan (CS was prepared from Artemia urmiana cyst shells using the same chemical process as described for the other crustacean species, with minor adjustments in the treatment conditions. The influence of modifications of the CS production process on the physiochemical and functional properties of the CS obtained was examined. The study results indicate that Artemia urmiana cyst shells are a rich source of chitin as 29.3-34.5% of the shell’s dry weight consisted of this material. Compared to crab CS (selected as an example of CS from a different crustacean source Artemia CS exhibited a medium molecular weight (4.5-5.7 ×105 Da, lower degree of deacetylation (67-74% and lower viscosity (29-91 centiposes. The physicochemical characteristics (e.g., ash, nitrogen and molecular weight and functional properties (e.g., water binding capacity and antibacterial activity of the prepared Artemia CSs were enhanced, compared to control and commercial samples, by varying the processing step sequence.

  18. Preparation of chitosan from brine shrimp (Artemia urmiana) cyst shells and effects of different chemical processing sequences on the physicochemical and functional properties of the product.

    Science.gov (United States)

    Tajik, Hossein; Moradi, Mehran; Rohani, Seyed Mehdi Razavi; Erfani, Amir Mehdi; Jalali, Farnood Shokouhi Sabet

    2008-06-06

    Chitosan (CS) was prepared from Artemia urmiana cyst shells using the same chemical process as described for the other crustacean species, with minor adjustments in the treatment conditions. The influence of modifications of the CS production process on the physiochemical and functional properties of the CS obtained was examined. The study results indicate that Artemia urmiana cyst shells are a rich source of chitin as 29.3-34.5% of the shell's dry weight consisted of this material. Compared to crab CS (selected as an example of CS from a different crustacean source) Artemia CS exhibited a medium molecular weight (4.5-5.7 x10(5) Da), lower degree of deacetylation (67-74%) and lower viscosity (29-91 centiposes). The physicochemical characteristics (e.g., ash, nitrogen and molecular weight) and functional properties (e.g., water binding capacity and antibacterial activity) of the prepared Artemia CSs were enhanced, compared to control and commercial samples, by varying the processing step sequence.

  19. Automated radioanalytical system incorporating microwave-assisted sample preparation, chemical separation, and online radiometric detection for the monitoring of total 99Tc in nuclear waste processing streams.

    Science.gov (United States)

    Egorov, Oleg B; O'Hara, Matthew J; Grate, Jay W

    2012-04-01

    An automated fluidic instrument is described that rapidly determines the total (99)Tc content of aged nuclear waste samples, where the matrix is chemically and radiologically complex and the existing speciation of the (99)Tc is variable. The monitor links microwave-assisted sample preparation with an automated anion exchange column separation and detection using a flow-through solid scintillator detector. The sample preparation steps acidify the sample, decompose organics, and convert all Tc species to the pertechnetate anion. The column-based anion exchange procedure separates the pertechnetate from the complex sample matrix, so that radiometric detection can provide accurate measurement of (99)Tc. We developed a preprogrammed spike addition procedure to automatically determine matrix-matched calibration. The overall measurement efficiency that is determined simultaneously provides a self-diagnostic parameter for the radiochemical separation and overall instrument function. Continuous, automated operation was demonstrated over the course of 54 h, which resulted in the analysis of 215 samples plus 54 hly spike-addition samples, with consistent overall measurement efficiency for the operation of the monitor. A sample can be processed and measured automatically in just 12.5 min with a detection limit of 23.5 Bq/mL of (99)Tc in low activity waste (0.495 mL sample volume), with better than 10% RSD precision at concentrations above the quantification limit. This rapid automated analysis method was developed to support nuclear waste processing operations planned for the Hanford nuclear site.

  20. Preparation of photocatalytic Fe 2O 3-TiO 2 coatings in one step by metal organic chemical vapor deposition

    Science.gov (United States)

    Zhang, Xingwang; Lei, Lecheng

    2008-02-01

    There are two major difficulties in the TiO 2 liquid-solid photocatalytic system: effective immobilization of the TiO 2 particles; and improving the catalytic activity under visible light. To simultaneously solve these two problems, Fe 2O 3-TiO 2 coatings supported on activated carbon fiber (ACF), have been prepared in one step by a convenient and efficient method—metal organic chemical vapor deposition (MOCVD). XRD results revealed that Fe 2O 3-TiO 2 coatings mainly composed of anatase TiO 2, α-Fe 2O 3 phases and little Fe 2Ti 3O 9. The pore structure of ACF was preserved well after loading with Fe 2O 3-TiO 2 coatings. UV-vis diffuse reflectance spectra showed a slight shift to longer wavelengths and an enhancement of the absorption in the visible region for Fe 2O 3-TiO 2 coatings, compared to the pure TiO 2 sample. A moderate Fe 2O 3-TiO 2 loading (13.7 wt%) was beneficial to mineralizing wastewater because the intermediates could be adsorbed onto the surface of photocatalyst following decomposition. The stable performance revealed that the Fe 2O 3-TiO 2 coatings were strongly adhered to the ACF surface, and the as prepared catalysts could be reused showing potential application for wastewater treatment.

  1. 工业双戊烯在精细化学品制备中的应用%Application of industrial dipentene in preparation of fine chemicals

    Institute of Scientific and Technical Information of China (English)

    苗雨欣; 蒋丽虹; 王昊; 王亚明

    2011-01-01

    介绍了工业双戊烯的来源、组成和物理化学性质.从双戊烯合成香料、催化加氢合成对盖烷、双戊烯合成萜烯马来酸酐加合物、双戊烯脱氢合成对伞花烃等4个方面综述了工业双戊烯在精细化学品制备中的应用情况;分析总结了国内外的研究进展、合成方法及反应条件;并提出了解决双戊烯工业化问题的有效途径.%Sources, composition, as well as physical and chemical properties of industrial dipentene were described. Applications of industrial dipentene in manufacture of fine chemicals were summarized as four categories, namely: synthesis of aroma compounds, synthesis of p - menthane through catalytic hydrogenation,preparation of terpene maleic anhydride adducts and synthesis of p- eymene through dipentene dehydrogenation. Progress in research work with respect to methods for synthesis and reaction conditions for making the above mentioned products were presented. Effective way to get industrial dipentene on a commercial scale was proposed.

  2. Preparation and Characterization of Ca3Co4O9 Thin Films on Polycrystalline Al2O3 Substrates by Chemical Solution Deposition

    Institute of Scientific and Technical Information of China (English)

    Yankun Fu; Xianwu Tang; Jie Yang; Hongbin Jian; Xuebin Zhu; Yuping Sun

    2013-01-01

    Ca3Co4O9 thin films have been first prepared on polycrystalline Al2O3 substrates using chemical solution deposition method by multiple annealing processing.It is observed that the derived thin films are c-axis oriented although the substrates are polycrystalline Al2O3 substrates,suggesting the self-assembled c-axis orientation.The annealing temperature effects on the properties are investigated and discussed.The best performances are attributed to the 850 ℃-annealed sample,whose resistivity,Seebeck coefficient and power factor at 300 K are 7.4 mΩ cm,117 μV/K and 0.18 mW/m K-2 respectively,which is even better than those of the thin films deposited on single crystal substrates.The results will provide an effective route to optimize the properties of Ca3Co4O9 thin films using chemical solution deposition by multiple annealing processing even the substrates are polycrystalline.

  3. The isotype ZnO/SiC heterojunction prepared by molecular beam epitaxy--A chemical inert interface with significant band discontinuities.

    Science.gov (United States)

    Zhang, Yufeng; Lin, Nanying; Li, Yaping; Wang, Xiaodan; Wang, Huiqiong; Kang, Junyong; Wilks, Regan; Bär, Marcus; Mu, Rui

    2016-01-01

    ZnO/SiC heterojunctions show great potential for various optoelectronic applications (e.g., ultraviolet light emitting diodes, photodetectors, and solar cells). However, the lack of a detailed understanding of the ZnO/SiC interface prevents an efficient and rapid optimization of these devices. Here, intrinsic (but inherently n-type) ZnO were deposited via molecular beam epitaxy on n-type 6H-SiC single crystalline substrates. The chemical and electronic structure of the ZnO/SiC interfaces were characterized by ultraviolet/x-ray photoelectron spectroscopy and x-ray excited Auger electron spectroscopy. In contrast to the ZnO/SiC interface prepared by radio frequency magnetron sputtering, no willemite-like zinc silicate interface species is present at the MBE-ZnO/SiC interface. Furthermore, the valence band offset at the abrupt ZnO/SiC interface is experimentally determined to be (1.2 ± 0.3) eV, suggesting a conduction band offset of approximately 0.8 eV, thus explaining the reported excellent rectifying characteristics of isotype ZnO/SiC heterojunctions. These insights lead to a better comprehension of the ZnO/SiC interface and show that the choice of deposition route might offer a powerful means to tailor the chemical and electronic structures of the ZnO/SiC interface, which can eventually be utilized to optimize related devices. PMID:26976240

  4. Characterization of CuInS{sub 2} thin films prepared by chemical bath deposition and their implementation in a solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Lugo, S.; López, I. [Universidad Autónoma de Nuevo León, UANL, Facultad de Ciencias Químicas, Laboratorio de Materiales I, Av. Universidad, Cd. Universitaria 66451, San Nicolás de los Garza, Nuevo León, México (Mexico); Peña, Y., E-mail: yolapm@gmail.com [Universidad Autónoma de Nuevo León, UANL, Facultad de Ciencias Químicas, Laboratorio de Materiales I, Av. Universidad, Cd. Universitaria 66451, San Nicolás de los Garza, Nuevo León, México (Mexico); Calixto, M. [Instituto de Energías Renovables, Universidad Nacional Autónoma de México, C.P. 62580, Temixco, Morelos, México (Mexico); Hernández, T. [Universidad Autónoma de Nuevo León, UANL, Facultad de Ciencias Químicas, Laboratorio de Materiales I, Av. Universidad, Cd. Universitaria 66451, San Nicolás de los Garza, Nuevo León, México (Mexico); Messina, S. [Universidad Autónoma de Nayarit, Ciudad de la Cultura “Amado Nervo”, S/N C.P. 63155, Tepic, Nayarit, México (Mexico); and others

    2014-10-31

    CuInS{sub 2} thin films were formed by the sequential deposition of In{sub 2}S{sub 3}–CuS layers on glass substrates, by chemical bath deposition technique, and heating these multilayer 1 h at 350 °C and 400 mPa. The morphology and thickness of the CuInS{sub 2} thin films were analysed by scanning electron microscopy, showing particles with elongated shape and length about 40 nm, and thickness of 267 and 348 nm for samples from 15 and 24 h of deposition time in the chemical bath of In{sub 2}S{sub 3}, respectively. The energy band gap values of the films were around 1.4 eV, whereas the electrical conductivity showed values from 64.91 to 4.11 × 10{sup −3} Ω{sup −1} cm{sup −1} for the samples of 15 and 24 h of In{sub 2}S{sub 3} deposition bath, respectively. The obtained CuInS{sub 2} films showed appropriate values for their application as an absorbing layer in photovoltaic structures of the type: glass/SnO{sub 2}:F/CdS/Sb{sub 2}S{sub 3}/CuInS{sub 2}/PbS/C/Ag. The whole structure was obtained through chemical bath deposition technique. The solar cell corresponding to 15 h of In{sub 2}S{sub 3} deposition duration bath showed energy-conversion efficiency (η) of 0.53% with open circuit voltage (V{sub oc}) of 530 mV, short circuit current density (J{sub sc}) of 2.43 mA cm{sup −2}, and fill factor (FF) of 0.41. In the case of the structure with 24 h of deposition of In{sub 2}S{sub 3} bath, η = 0.43% was measured with the following parameters: V{sub oc} = 330 mV, J{sub sc} = 4.78 mA cm{sup −2} and FF = 0.27. - Highlights: • CuInS{sub 2} films were formed by chemical bath deposition followed by a heat treatment. • Prepared CuInS{sub 2} thin films can work as an effective absorbing layer in a solar cell. • A complete solar cell structure was made by a chemical bath deposition method.

  5. TiO{sub 2} based photo-catalysts prepared by chemical vapor infiltration (CVI) on micro-fibrous substrates; Photocatalyseurs a base de TiO{sub 2} prepares par infiltration chimique en phase vapeur (CVI) sur supports microfibreux

    Energy Technology Data Exchange (ETDEWEB)

    Sarantopoulos, Ch

    2007-10-15

    This thesis deals with micro-fibrous glass substrates functionalized with TiO{sub 2}. The oxide is deposited as a thin film onto the micro fibres by chemical vapour infiltration (CVI), yielding a photo-catalytic material usable for cleaning polluted air. We studied the relation between the structure of the material and its photo-catalytic efficiency. TiO{sub 2} thin films were prepared at low pressure, in a hot-wall CVD reactor, using Ti(O-iPr){sub 4} as a precursor. They were characterized by XRD, SEM, EDX, XPS and BET, and by recording the kinetics of decomposition of varied pollutants in solution (orange G, malic acid, imazapyr) and in air (toluene). The conditions favoring the growth of porous films through a columnar growth mode were established by MOCVD-depositing TiO{sub 2} thin films on flat substrates. The subsequent works with micro fibrous thick substrates showed the uniformity of infiltration to be the main factor governing the photo-catalytic efficiency. Operating parameters that optimize infiltration do not yield columnar growth mode. A compromise is necessary. Our photo-catalysts are showing high efficiency comparable, if not higher, to those actually commercialized. These promising results are opening real perspectives for the proposed process. (author)

  6. A Novel Strategy for Preparation of Si-HA Coatings on C/C Composites by Chemical Liquid Vaporization Deposition/Hydrothermal Treatments

    Science.gov (United States)

    Xin-Bo, Xiong; Xin-Ye, Ni; Ya-Yun, Li; Cen-Cen, Chu; Ji-Zhao, Zou; Xie-Rong, Zeng

    2016-08-01

    A novel strategy for the preparation of Si-doped hydroxyapatite (Si-HA) coatings on H2O2-treated carbon/carbon composites (C/C) was developed. HA coating was prepared on C/C through chemical liquid vaporization deposition (CLVD)/hydrothermal treatment. HA coating was immersed in an H2SiO3 solution at an autoclave at 413 K for transformation into Si-HA coating. The effects of H2SiO3 mass contents on the phase, morphology, and composition of the Si-HA coatings were studied through SEM, EDS,XRD, and FTIR. Their bonding performance to C/C was measured through a scratch test. Under the optimal content condition, the in vitro skull osteoblast response behaviors of the Si-HA coating were evaluated. Results showed that SiO32‑ could enter into the HA lattice and occupy the PO43‑ sites. Doped SiO32‑ significantly improved the bonding performance of the HA coating to C/C in comparison with the untreated HA. The adhesive strength of the coatings initially increased and then decreased with increasing H2SiO3 content. Meanwhile, the cohesive strength of the Si-HA coatings was almost nearly identical. The Si-HA coating achieved at a content of 90% H2SiO3 exhibited the best bonding performance, and its osteoblast compatibility in vitro was superior to that of the untreated HA coating on C/C through CLVD/hydrothermal treatment.

  7. A Novel Strategy for Preparation of Si-HA Coatings on C/C Composites by Chemical Liquid Vaporization Deposition/Hydrothermal Treatments.

    Science.gov (United States)

    Xin-Bo, Xiong; Xin-Ye, Ni; Ya-Yun, Li; Cen-Cen, Chu; Ji-Zhao, Zou; Xie-Rong, Zeng

    2016-08-05

    A novel strategy for the preparation of Si-doped hydroxyapatite (Si-HA) coatings on H2O2-treated carbon/carbon composites (C/C) was developed. HA coating was prepared on C/C through chemical liquid vaporization deposition (CLVD)/hydrothermal treatment. HA coating was immersed in an H2SiO3 solution at an autoclave at 413 K for transformation into Si-HA coating. The effects of H2SiO3 mass contents on the phase, morphology, and composition of the Si-HA coatings were studied through SEM, EDS,XRD, and FTIR. Their bonding performance to C/C was measured through a scratch test. Under the optimal content condition, the in vitro skull osteoblast response behaviors of the Si-HA coating were evaluated. Results showed that SiO3(2-) could enter into the HA lattice and occupy the PO4(3-) sites. Doped SiO3(2-) significantly improved the bonding performance of the HA coating to C/C in comparison with the untreated HA. The adhesive strength of the coatings initially increased and then decreased with increasing H2SiO3 content. Meanwhile, the cohesive strength of the Si-HA coatings was almost nearly identical. The Si-HA coating achieved at a content of 90% H2SiO3 exhibited the best bonding performance, and its osteoblast compatibility in vitro was superior to that of the untreated HA coating on C/C through CLVD/hydrothermal treatment.

  8. Preparation of nanocrystalline Ni doped ZnS thin films by ammonia-free chemical bath deposition method and optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Sahraei, Reza, E-mail: r.sahraei@ilam.ac.ir; Darafarin, Soraya

    2014-05-01

    Nanocrystalline Ni doped ZnS thin films were deposited on quartz, silicon, and glass substrates using chemical bath deposition method in a weak acidic solution containing ethylenediamine tetra acetic acid disodium salt (Na{sub 2}EDTA) as a complexing agent for zinc ions and thioacetamide (TAA) as a sulfide source at 80 °C. The films were characterized by energy-dispersive X-ray spectrometer (EDX), inductively coupled plasma atomic emission spectroscopy (ICP-AES), Fourier transform-infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet–visible spectrophotometry, and photoluminescence (PL) spectroscopy. UV–vis transmission data showed that the films were transparent in the visible region. The X-ray diffraction analysis showed a cubic zinc blend structure. FE-SEM revealed a homogeneous morphology and dense nanostructures. The PL spectra of the ZnS:Ni films showed two characteristic bands, one broad band centered at 430 and another narrow band at 523 nm. Furthermore, concentration quenching effect on the photoluminescence intensity has been observed. - Highlights: • Nanocrystalline ZnS:Ni thin films were prepared by the chemical bath deposition method. • The size of ZnS:Ni nanocrystals was less than 10 nm showing quantum size effect. • SEM images demonstrated a dense and uniform surface that was free of pinholes. • The deposited films were highly transparent (>70%) in the visible region. • The PL spectra of ZnS:Ni thin films showed two emission peaks at 430 and 523 nm.

  9. Preparation and Characterization of Graphene Oxide by Chemical Exfoliation%化学剥离制备氧化石墨烯及表征

    Institute of Scientific and Technical Information of China (English)

    王增奎; 张国喜; 刘聿成; 张军; 张永涛

    2012-01-01

      以无硫膨胀石墨为原料,采用化学剥离法制备出氧化石墨烯。利用X射线衍射仪(XRD)分析膨胀石墨、氧化石墨、氧化石墨烯的晶体结构;利用傅里叶变换红外光谱仪(FTIR)研究氧化石墨、氧化石墨烯表面的红外光谱特征。结果表明:对于制备氧化石墨烯,化学剥离这种方法是可行的。另外,FTIR图谱表明,氧化石墨的表面和边缘含有大量的环氧基、羟基等官能团,有利于其在N,N-二甲基甲酰胺溶液中经超声剥离获得质量较好的氧化石墨烯薄片。%  Chemical exfoliation is proposed to produce graphene oxide, using sulfur-free expanded graphite. X-ray diffraction was employed to evaluate the structural properties of expanded graphite, expanded graphite oxide, and graphene oxide. The FITR spectroscopy was used to demonstrate infrared spectroscopy characteristics of the surface of expanded graphite oxide and graphene oxide. Results show that chemical exfoliation is feasible for preparing graphene oxide. In addition, the FTIR spectra indicate that large amounts of bear hydroxyl and epoxide functional groups attached onto the surface and the sheet edges of expanded graphite oxide, which were propitious to obtain high-quality graphene oxide sheets using ultrasonic dispersion in N, N-dimethylformamide.

  10. Preparation of activated carbons from walnut shells by vacuum chemical activation%核桃壳真空化学活化制备活性炭

    Institute of Scientific and Technical Information of China (English)

    杨娟; 丘克强

    2012-01-01

    Activated carbons were prepared from walnut shells by vacuum chemical activation. The effects of system pressure, activation temperature and impregnation ratio on the properties (BET surface area, pore size distribution, iodine and methylene blue adsorption values, and surface characteristics) of activated carbon were studied. The results show that the BET surface area and total pore volume of activated carbon obtained at system pressure of 30 kPa have increased by 27% and 25% respectively compared with those of activated carbon prepared under atmospheric condition. Vacuum condition is beneficial to develop microporous structure, and mesopore tends to be well developed at high impregnation ratio. The activated carbon prepared at system pressure of 30 kPa, activation temperature of 450 ℃, and impregnation ratio of 2.0, possesses a BET surface area of 1 800 m2/g, a total pore volume of 1.176 cm3/g, an iodine adsorption value of 1 050 mg/'g. a methylene blue adsorption value of 315 mg/g and an isoelectric point of 9.15.%采用真空化学活化法,以核桃壳为原料,氯化锌为活化剂制备活性炭,探讨体系压力、活化温度、浸渍比对活性炭比表面积、孔径分布、碘值和亚甲基蓝值以及表面性质的影响.研究结果表明,30 kPa时制备的活性炭其比表面积和总孔体积比常压条件时分别提高了27%和25%;在低压条件下有利于微孔的形成,在高浸渍比的条件下有利于中孔的形成.在体系压力为30 kPa,活化温度为450℃,浸渍比为2.0时,所得活性炭的BET比表面积为1800 m2/g,总孔体积为1.176 cm3/g,等电点为9.15,碘吸附量为1050 mg/g,亚甲基蓝吸附量为315 mg/g.

  11. Removal of Zn(II) and Hg(II) from aqueous solution on a carbonaceous sorbent chemically prepared from rice husk

    International Nuclear Information System (INIS)

    A carbonaceous sorbent was prepared from rice husk via sulfuric acid treatment. Sorption of Zn(II) and Hg(II) from aqueous solution was studied varying time, pH, metal concentration, temperature and sorbent status (wet and dry). Zn(II) sorption was found fast reaching equilibrium within ∼2 h while Hg(II) sorption was slow reaching equilibrium within ∼120 h with better performance for the wet sorbent than for the dry. Kinetics data for both metals were found to follow pseudo-second order model. Sorption rate of both metals was enhanced with temperature rise. Activation energy, Ea, for Zn(II) sorption, was ∼13.0 kJ/mol indicating a diffusion-controlled process ion exchange process, however, for Hg(II) sorption, Ea was ∼54 kJ/mol indicating a chemically controlled process. Sorption of both metals was low at low pH and increased with pH increase. Sorption was much higher for Hg(II) than for Zn(II) with higher uptake for both metals by rising the temperature. Hg(II) was reduced to Hg(I) on the sorbent surface. This was confirmed from the identification of Hg2Cl2 deposits on the sorbent surface by scanning electron microscopy and X-ray diffraction. However, no redox processes were observed in Zn(II) sorption. Sorption mechanism is discussed.

  12. Ordered silicon nanowire arrays prepared by an improved nanospheres self-assembly in combination with Ag-assisted wet chemical etching

    Science.gov (United States)

    Jia, Guobin; Westphalen, Jasper; Drexler, Jan; Plentz, Jonathan; Dellith, Jan; Dellith, Andrea; Andrä, Gudrun; Falk, Fritz

    2016-04-01

    An improved Langmuir-Blodgett self-assembly process combined with Ag-assisted wet chemical etching for the preparation of ordered silicon nanowire arrays is presented in this paper. The new process is independent of the surface conditions (hydrophilic or hydrophobic) of the substrate, allowing for depositing a monolayer of closely packed polystyrene nanospheres onto any flat surface. A full control of the morphology of the silicon nanowire is achieved. Furthermore, it is observed that the formation of porous-Si at the tips of the nanowires is closely related to the release of Ag nanoparticles from the Ag mask during the etching, which subsequently redeposit on the surface initially free of Ag, and these Ag nanoparticles catalyze the etching of the tips and lead to the porous-Si formation. This finding will help to improve the resulting nano- and microstructures to get them free of pores, and renders it a promising technology for low-cost high throughput fabrication of specific optical devices, photonic crystals, sensors, MEMS, and NEMS by substituting the costly BOSCH process. It is shown that ordered nanowire arrays free of porous structures can be produced if all sources of Ag nanoparticles are excluded, and structures with aspect ratio more than 100 can be produced.

  13. Step Coverage and Electrical Properties of (Ba, Sr)TiO3 Films Prepared by Liquid Source Chemical Vapor Deposition Using TiO(DPM)2

    Science.gov (United States)

    Kawahara, Takaaki; Yamamuka, Mikio; Makita, Tetsuro; Naka, Jiro; Yuuki, Akimasa; Mikami, Noboru; Ono, Kouichi

    1994-09-01

    Thin films of (Ba, Sr)TiO3 (BST) with high dielectric constant were prepared on Pt/ SiO2/Si substrates of 6-inch-diameter by liquid source chemical vapor deposition using Ba(DPM)2, Sr(DPM)2 and TiO(DPM)2 (DPM=dipivaloylmethanato; C11H19O2) dissolved in tetrahydrofuran (THF). The reproducibility of ±3 % for the film composition was achieved by optimizing the deposition procedures. It was found that the coverage of 72%, obtained at the substrate temperature T s=753 K, was better than those obtained using other Ti sources such as Ti(O-i-Pr)4 (TTIP) and Ti(O-i-Pr)2(DPM)2. The electrical properties of the 480-Å-thick BST film, deposited at T s=753 K using TiO(DPM)2, were as follows: dielectric constant ɛ=230, equivalent SiO2 thickness t eq=7.8 Å, leakage current density J L=6.7×10-6 A/cm2 at 1.65 V and dielectric loss tan δ=0.013.

  14. A highly porous NiO/polyaniline composite film prepared by combining chemical bath deposition and electro-polymerization and its electrochromic performance

    Science.gov (United States)

    Xia, X. H.; Tu, J. P.; Zhang, J.; Wang, X. L.; Zhang, W. K.; Huang, H.

    2008-11-01

    A highly porous NiO/polyaniline (PANI) composite film was prepared on ITO glass by combining the chemical bath deposition and electro-polymerization methods, successively. The porous NiO film acts as a template for the preferential growth of PANI along NiO flakes, and the NiO/PANI composite film has an intercrossing net-like morphology. The electrochromic performance of the NiO/PANI composite film was investigated in 1 M LiClO4+1 mM HClO4/propylene carbonate (PC) by means of transmittance, cyclic voltammetry (CV) and chronoamperometry (CA) measurements. The NiO/PANI thin film exhibits a noticeable electrochromism with reversible color changes from transparent yellow to purple and presents quite good transmittance modulation with a variation of transmittance up to 56% at 550 nm. The porous NiO/polyaniline (PANI) composite film also shows good reaction kinetics with fast switching speed, and the response time for oxidation and reduction is 90 and 110 ms, respectively.

  15. A highly porous NiO/polyaniline composite film prepared by combining chemical bath deposition and electro-polymerization and its electrochromic performance

    International Nuclear Information System (INIS)

    A highly porous NiO/polyaniline (PANI) composite film was prepared on ITO glass by combining the chemical bath deposition and electro-polymerization methods, successively. The porous NiO film acts as a template for the preferential growth of PANI along NiO flakes, and the NiO/PANI composite film has an intercrossing net-like morphology. The electrochromic performance of the NiO/PANI composite film was investigated in 1 M LiClO4+1 mM HClO4/propylene carbonate (PC) by means of transmittance, cyclic voltammetry (CV) and chronoamperometry (CA) measurements. The NiO/PANI thin film exhibits a noticeable electrochromism with reversible color changes from transparent yellow to purple and presents quite good transmittance modulation with a variation of transmittance up to 56% at 550 nm. The porous NiO/polyaniline (PANI) composite film also shows good reaction kinetics with fast switching speed, and the response time for oxidation and reduction is 90 and 110 ms, respectively.

  16. Preparation and textural characterisation of activated carbon from vine shoots ( Vitis vinifera) by H 3PO 4—Chemical activation

    Science.gov (United States)

    Corcho-Corral, B.; Olivares-Marín, M.; Fernández-González, C.; Gómez-Serrano, V.; Macías-García, A.

    2006-06-01

    An abundant and low-cost agricultural waste as vine shoots ( Vitis vinifera) (VS), which is generated by the annual pruning of vineyards, has been used as raw material in the preparation of powder activated carbon (AC) by the method of chemical activation with phosphoric acid. After size reduction, VS were impregnated for 2 h with 60 wt.% H 3PO 4 solution at room temperature, 50 and 85 °C. The three impregnated products were carbonised at 400 °C. The product impregnated at 50 °C was heated either first at 150-250 °C and then at 400 °C or simply at 350-550 °C in N 2 atmosphere. The time of isothermal treatment after each dynamic heating was 2 h. The carbons were texturally characterised by gas adsorption (N 2, -196 °C), mercury porosimetry, and density measurements. FT-IR spectroscopy was also applied. Better developments of surface area and microporosity are obtained when the impregnation of VS with the H 3PO 4 solution is effected at 50 °C and for the products heated isothermally at 200 and 450 °C. The mesopore volume is also usually higher for the products impregnated and heated at intermediate temperatures.

  17. Solution preparation

    International Nuclear Information System (INIS)

    Reviewed in this statement are methods of preparing solutions to be used in laboratory experiments to examine technical issues related to the safe disposal of nuclear waste from power generation. Each approach currently used to prepare solutions has advantages and any one approach may be preferred over the others in particular situations, depending upon the goals of the experimental program. These advantages are highlighted herein for three approaches to solution preparation that are currently used most in studies of nuclear waste disposal. Discussion of the disadvantages of each approach is presented to help a user select a preparation method for his particular studies. Also presented in this statement are general observations regarding solution preparation. These observations are used as examples of the types of concerns that need to be addressed regarding solution preparation. As shown by these examples, prior to experimentation or chemical analyses, laboratory techniques based on scientific knowledge of solutions can be applied to solutions, often resulting in great improvement in the usefulness of results

  18. Ultra-high performance liquid chromatography coupled with quadrupole/time of flight mass spectrometry based chemical profiling approach for the holistic quality control of complex Kang-Jing formula preparations.

    Science.gov (United States)

    Yang, Xiao-Huan; Cheng, Xiao-Lan; Qin, Bing; Cai, Zhuo-Ya; Cai, Xiong; Liu, Shao; Wang, Qi; Qin, Yong

    2016-05-30

    The Kang-Jing (KJ) formula is a compound preparation made from 12 kinds of herbs. So far, four different methods (M1-M4) have been documented for KJ preparation, but the influence of preparation methods on the holistic quality of KJ have remained unknown. In this study, a strategy was proposed to investigate the influence of different preparation methods on the holistic quality of KJ using ultra-high performance liquid chromatography coupled with quadrupole/time of flight mass spectrometry (UHPLC-QTOF-MS/MS) based chemical profiling. A total of 101 compounds mainly belonging to flavonoids, tanshinones, monoterpene glycosides, triterpenoid saponins, alkaloids, phenolic acids and volatile oils, were identified. Among these compounds, glaucine was detected only in M3/M4 samples, while two dehydrocorydaline isomers merely detected in M2/M3/M4 samples. Tetrahydrocolumbamine, ethylic lithospermic acid, salvianolic acid E and rosmarimic acid were only detected in M1/M3/M4 samples. In the subsequent quantitative analysis, 12 major compounds were determined by UHPLC-MS/MS. The proposed method was validated with respect to linearity, accuracy, precision and recovery. It was found that the contents of marker compounds varied significantly in samples prepared by different methods. These results demonstrated that preparation method does significantly affect the holistic quality of KJ. UHPLC-QTOF-MS/MS based chemical profiling approach is efficient and reliable for comprehensive quality evaluation of KJ. Collectively, this study provide the chemical evidence for revealing the material basis of KJ, and establish a simple and accurate chemical profiling method for its quality control. PMID:26977585

  19. Low-temperature selective catalytic reduction of NO with NH3 over nanoflaky MnOx on carbon nanotubes in situ prepared via a chemical bath deposition route

    Science.gov (United States)

    Fang, Cheng; Zhang, Dengsong; Cai, Sixiang; Zhang, Lei; Huang, Lei; Li, Hongrui; Maitarad, Phornphimon; Shi, Liyi; Gao, Ruihua; Zhang, Jianping

    2013-09-01

    Nanoflaky MnOx on carbon nanotubes (nf-MnOx@CNTs) was in situ synthesized by a facile chemical bath deposition route for low-temperature selective catalytic reduction (SCR) of NO with NH3. This catalyst was mainly characterized by the techniques of X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), N2 adsorption-desorption analysis, X-ray photoelectron spectroscopy (XPS), H2 temperature-programmed reduction (H2-TPR) and NH3 temperature-programmed desorption (NH3-TPD). The SEM, TEM, XRD results and N2 adsorption-desorption analysis indicated that the CNTs were surrounded by nanoflaky MnOx and the obtained catalyst exhibited a large surface area as well. Compared with the MnOx/CNT and MnOx/TiO2 catalysts prepared by an impregnation method, the nf-MnOx@CNTs presented better NH3-SCR activity at low temperature and a more extensive operating temperature window. The XPS results showed that a higher atomic concentration of Mn4+ and more chemisorbed oxygen species existed on the surface of CNTs for nf-MnOx@CNTs. The H2-TPR and NH3-TPD results demonstrated that the nf-MnOx@CNTs possessed stronger reducing ability, more acid sites and stronger acid strength than the other two catalysts. Based on the above mentioned favourable properties, the nf-MnOx@CNT catalyst has an excellent performance in the low-temperature SCR of NO to N2 with NH3. In addition, the nf-MnOx@CNT catalyst also presented favourable stability and H2O resistance.Nanoflaky MnOx on carbon nanotubes (nf-MnOx@CNTs) was in situ synthesized by a facile chemical bath deposition route for low-temperature selective catalytic reduction (SCR) of NO with NH3. This catalyst was mainly characterized by the techniques of X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), N2 adsorption-desorption analysis, X-ray photoelectron spectroscopy (XPS), H2 temperature-programmed reduction (H2-TPR) and NH3 temperature

  20. Preparation and rechargeability of chemical modified manganese dioxide%化学改性MnO2的制备及可充性

    Institute of Scientific and Technical Information of China (English)

    郭炳焜; 杨子运; 李新海; 徐徽; 刘丽英

    2001-01-01

    制备可充锌锰电池的关键技术之一是提高MnO2的可逆性。采用化学沉淀氧化法制备改性MnO2。研究了锰盐、掺杂物质、氧化剂、温度等对MnO2可逆性的影响。采用模拟电池及微电极技术研究MnO2的充放电性能,结合XRD、SEM检测改性MnO2的晶形和形貌。实验结果表明,当以Bi(NO3)3为掺杂物质时,制备改性MnO2的优化工艺条件是:n(Mn)/n(Bi)(摩尔比)为6~10,氧化剂用NaClO,锰盐可用Mn(NO3)2或MnSO4,25 ℃,反应时间10~15 h。所得改性MnO2呈疏松微晶粒状,是以β-MnOOH为主的β-MnOOH与β-BiOOH的混合晶相。该样品经第10次循环充放电后,其放电容量为初始放电容量的121%,10次累积放电容量是电解MnO2(EMD)的3倍。表明掺Bi3+对改善MnO2的可逆性和提高放电容量有重要作用。%Enhancing the invertibility of MnO2 was one of key technologies of preparing chargeable Zn-MnO2 battery. Chemical deposition oxidation was adopted to prepare modified MnO2 and manganic compounds, adulterants, oxidants, humidity effected to invertibility of MnO2 were studied. Charge and discharge capability of MnO2 was studied by adopting simulation cell and microelectrode. Crystal and shape of modified MnO2 were detected by XRD and SEM. The results show that the optimal technological conditions for preparing modified MnO2 by using Bi(NO3)3 as adulterant is as following: mole ratio of n(Mn)/n(Bi) is 6~10, oxidant is NaClO, manganic compound is Mn(NO3)3 or MnSO4, temperature is 25 ℃, reaction time is 10~15 h. The modified MnO2 is loosen micro-crystal powder, which is mixture of β-MnOOH with a little β-BiOOH. The powders discharge capability is 121% of initial discharge capability after the tenth charge and discharge cycle. The cumulate discharge capability of the tenth charge and discharge cycle is triple electrolyze MnO2

  1. Sol-gel process preparation and evaluation of the analytical performances of an hydrazine specific chemical sensor; Preparation par procede sol-gel et evaluation des performances analytiques d`un capteur chimique specifique de l`hydrazine

    Energy Technology Data Exchange (ETDEWEB)

    Gojon, C

    1996-12-01

    The realisation of optical fibers active chemical collector to analyze hydrazine in line, in the spent fuel reprocessing process is the subject of this work. The p.dimethyl-amino-benzaldehyde has been chosen as reagent for its chemical and optical properties. 186 refs.

  2. Co3O4 protective coatings prepared by Pulsed Injection Metal Organic Chemical Vapour Deposition

    DEFF Research Database (Denmark)

    Burriel, M.; Garcia, G.; Santiso, J.;

    2005-01-01

    deposition temperature. Pure Co3O4 spinel structure was found for deposition temperatures ranging from 360 to 540 degreesC. The optimum experimental parameters to prepare dense layers with a high growth rate were determined and used to prepare corrosion protective coatings for Fe-22Cr metallic interconnects...

  3. Chemical characterization by GC-MS and in vitro activity against Candida albicans of volatile fractions prepared from Artemisia dracunculus, Artemisia abrotanum, Artemisia absinthium and Artemisia vulgaris

    OpenAIRE

    Obistioiu, Diana; Cristina, Romeo T; Schmerold, Ivo; Chizzola, Remigius; Stolze, Klaus; Nichita, Ileana; Chiurciu, Viorica

    2014-01-01

    Background A large number of essential oils is reported to have significant activity against Candida albicans. But the different chemical composition influences the degree of their activity. The intention of this study was to investigate the chemical composition and the activity against Candida albicans of volatile oils obtained from Artemisia dracunculus, A. abrotanum, A. absinthium and A. vulgaris (Asteraceae). The aim of the study was to identify new chemical compounds that have effect aga...

  4. Preparation of Quartzite Reference Materials for Chemical Composition Analysis%石英岩化学成分分析标准物质研制

    Institute of Scientific and Technical Information of China (English)

    刘調; 马玲; 时晓露; 查立新

    2014-01-01

    At present,quartzitic reference materials are prepared by Brazil,England,Japan,and South Africa but are not in series. The SiO2 contents in these reference materials are generally above 96% and accurate concentration values are determined for only small number of elements.To date,no quartzitic reference material has been prepared in China,which cannot meet the demand of quartzite exploration and practical applications.In this study,three quartzitic reference materials were developed with samples from representative quartz mining areas,namely Damiao Town, Fengyang County, Anhui Province;Jingyang Town, Datong County, Qinghai Province;and Lingqiu mountain,Qichun County,Hubei Province.The samples were finely crushed to -45 μm with a fluidized bed-type airflow crusher to prevent sample contamination.Homogeneity and stability testing was conducted chiefly by Inductively Coupled Plasma-Atomic Emission Spectrometry and Inductively Coupled Plasma-Mass Spectrometry rather than X-ray Fluorescence Spectrometry with tablet sample preparation,which results in the quartzite material being difficult to mould.F values for the variance test were less than the threshold,which indicated a good homogeneity.No significant statistical changes were observed in eight two-year stability tests.The short-term stability analysis in the condition of extreme temperatures and vibration were also consistent.Determined values were certified by 1 0 laboratories in China with multiple methods.For components without homogeneity and stability tests,values and relative uncertainty of 36 components were obtained by comparing similar elements.The three quartzitic reference materials have been approved as national standard reference materials (GBW 07835 , GBW07836 and GBW 07837),with 92.93%,95.97% and 99.18% of SiO2,respectively,as a gradient distributed series.The series of reference materials has the characteristics of uniform grading,narrow diameter distribution (D25 -D75 ranged between 4 -1 6

  5. 具有高比表面积的稻壳灰的制备及其化学活性的研究%Study on Preparation of Rice Husk Ash with High Specific Surface Area and Its Chemical Reactivity

    Institute of Scientific and Technical Information of China (English)

    冯庆革; 林清宇; 童张法; S.Sugita

    2004-01-01

    Preparation of rice husk ash with high specific surface area and chemical reactivity of the product are reported in this paper. The amorphous rice husk ash with high specific surface area of 311 m2·g-1 was produced by heating acid treated rice husk at 700℃ for 4 h. The isotherms of rice husk ash are similar in shape to type Ⅱof Brunaner's classification with mesopores being predominant. The rice husk ash has a high chemical reactivity,especially that pretreated with acid. This chemical reactivity depends on ashing temperature and pretreatment conditions. There is an exponential relation between the specific surface area of rice husk ash and the change in the conductivity of saturated Ca(OH)2 solution with rice husk ash, from which the specific surface area can be known according to the conductivity change.

  6. Study on the chemical processes of preparing of erythrose%化学法制备赤藓糖的研究

    Institute of Scientific and Technical Information of China (English)

    姜希生; 邱学良; 张亮; 李林; 郭艳敏

    2012-01-01

    赤藓糖是一种带有还原性醛基的四碳糖,在常规条件下结构不稳定,可通过加氢反应进一步制备赤藓糖醇.化学法制备赤藓糖的成功打破了赤藓糖醇行业目前仅由发酵法来实现的局限,对行业整体生产成本的降低具有重要的意义.本文所提的工艺是用葡萄糖酸钠配成溶液,在搅拌及一定的温度条件下,以六水氯化钴为催化剂,通过双氧水氧化制备赤藓糖.先通过单因素试验确定了葡萄糖酸钠的浓度、六水氯化钴和双氧水的用量、反应温度、双氧水加入时间等条件的变化曲线.通过正交实验筛选出葡萄糖酸钠氧化制备赤藓糖的最佳工艺条件,即六水氯化钴添加量为葡萄糖酸钠质量的1.4%、双氧水添加量和葡萄糖酸钠质量相同、葡萄糖酸钠溶液的浓度10%、氧化温度控制在40℃、在此最佳工艺条件下葡萄糖酸钠氧化为赤藓糖的转化纯度为59.9%.%Erythroseis a four-carbon sugar with a reducing aldehyde, and is unstable. Through hydrogenation reaction , itcan be used in the production oferythritol. This chemical process has broken the traditional fermentation erythri-tol industry. It costs less and has significant influence in erythritol industry. The technology uses cobalt chloride hexa-hydrate as a catalyst, sodium gluconate solution reacts with hydrogen peroxide under stirring and certain temperature to prepare erythrose. Single - factor test determined the concentration of sodium gluconate, cobalt chloride hexahydarte, hydrogen peroxide, reaction temperature and time. The relationship between the above factors and the yields of erythrose were showed in the diagrams. Base on orthogonal design experiment, the optimal pretreatment conditionis as follows; CoCl2 · 6H2O content is 1.4% of sodium gluconate, hydrogen peroxide content is the same to the weight of sodium gluconate, the solution concentration of sodium gluconate is 10% , the reaction temperature is

  7. Preparation of an antitumor and antivirus agent: chemical modification of α-MMC and MAP30 from Momordica Charantia L. with covalent conjugation of polyethyelene glycol

    Directory of Open Access Journals (Sweden)

    Meng Y

    2012-06-01

    Full Text Available Yao Meng,1,2 Shuangfeng Liu,1 Juan Li,3 Yanfa Meng,3 Xiaojun Zhao2,41School of Medical Laboratory Science, Chengdu Medical College, Chengdu, China; 2West China Hospital Laboratory of Nanomedicine and Institute for Nanobiomedical Technology and Membrane Biology, Sichuan University, Chengdu, China; 3Key Laboratory of Bio-resources and Eco-environment Ministry of Education/Animal Disease Prevention and Food Safety Key Laboratory of Sichuan Province, College of Life Science, Sichuan University, Chengdu, China; 4Center for Biomedical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USABackground: Alpha-momorcharin (α-MMC and momordica anti-HIV protein (MAP30 derived from Momordica charantia L. have been confirmed to possess antitumor and antivirus activities due to their RNA-N-glycosidase activity. However, strong immunogenicity and short plasma half-life limit their clinical application. To solve this problem, the two proteins were modified with (mPEG2-Lys-NHS (20 kDa.Methodology/principal findings: In this article, a novel purification strategy for the two main type I ribosome-inactivating proteins (RIPs, α-MMC and MAP30, was successfully developed for laboratory-scale preparation. Using this dramatic method, 200 mg of α-MMC and about 120 mg of MAP30 was obtained in only one purification process from 200 g of Momordica charantia seeds. The homogeneity and some other properties of the two proteins were assessed by gradient SDS-PAGE, electrospray ionization quadruple mass spectrometry, and N-terminal sequence analysis as well as Western blot. Two polyethylene glycol (PEGylated proteins were synthesized and purified. Homogeneous mono-, di-, or tri-PEGylated proteins were characterized by matrix-assisted laser desorption ionization-time of flight mass spectrometry. The analysis of antitumor and antivirus activities indicated that the serial PEGylated RIPs preserved moderate activities on JAR choriocarcinoma cells and herpes simplex

  8. Preparation of Ru/HSAG Catalysts for Ammonia Synthesis via Metal-Organic Chemical Vapour Deposition Technology%MOCVD法制备Ru/HSAG氨合成催化剂

    Institute of Scientific and Technical Information of China (English)

    严海宇; 黄仕良; 韩文锋; 刘化章

    2014-01-01

    Ruthenium catalysts supported on high surface area graphite (HSAG), impregnated with KNO3 and Ba(NO3)2,was prepared via metal-organic chemical vapour deposition technology(MOCVD) with tri-ruthenium dodecacarbonyl as the Ru precursor. The catalysts were characterized by X-ray diffraction, N2 physical adsorption and transmission electron microscope. The activity of the Ru catalyst for ammonia synthesis was evaluated. The results showed that the sublimation rate of tri-ruthenium dodecacarbony depends on temperature under vacuum and dark conditions. It is confirmed that uniform dispersion can be achieved via MOCVD route with Ru nanoparticle sizes around 2 nm. As Ru3(CO)12 commences to decompose at 130℃ and reach maximum decomposition rate at 175℃, the sublimation temperature is suggested to be 110-130℃. With the increase in Ru loading from 3.2% to 6.0%, as evidenced by TEM experiments, Ru nanoparticle size keeps unchanged (around 2 nm), while the activity for ammonia synthesis is enhanced dramatically, especially at low temperature (375℃).%采用金属有机物化学气相沉积技术(MOCVD)将羰基钌升华至已浸渍 KNO3和 Ba(NO3)2的高比表面石墨(HSAG)上,制备了一系列Ru/HSAG催化剂。采用X射线衍射、透射电镜(TEM)和N2物理吸附等表征手段,考察了催化剂的物相和表面结构性质及氨合成催化活性。结果表明,以化学气相沉积技术制备的催化剂,能使钌均匀地分散于载体中,形成较小的钌粒子,从而得到高活性的氨合成催化剂。羰基钌的加热温度对升华速率有很大影响,但对沉积效果和催化活性没有明显影响,负载的羰基钌含量对催化剂活性有显著影响。羰基钌在130℃开始分解,并在175℃达到最大分解速率,因此合适的升华温度为110~130℃。催化剂的钌负载量(质量分数)从3.2%增至6.0%时,低反应温度(375℃)下,氨合成活性明显提高。在实验负载量范围内

  9. Impact of Bhavana Samskara on physico-chemical parameters with special reference to Gandhaka Rasayana prepared by different media and methods.

    Science.gov (United States)

    Mitra, Shuchi; Prajapati, P K; Shukla, V J; Ravishankar, B

    2010-07-01

    Gandhaka Rasayana is frequently used in the management of different skin disorders (Kushtha). It is a herbo-mineral preparation prepared by Shuddha Gandhaka Bhavit with 11 herbal drugs in a serial manner for eight times each. Therefore, it was used as a model drug and four samples were prepared by adopting different methods and media. The physicochemical parameters were evaluated. The effect of increasing the number of Bhavana (lavigation) on particle size of the drug was examined. Similarly, an attempt was also made to differntiate the structure (surface anatomy) of the drug with Bhavana and without Bhavana by using a very sophisticated x-ray photo electron spectrometer (XPS) study. Overall, a remarkable difference was observed in the samples with Bhavana and without Bhavana. PMID:22131744

  10. The study on the preparation and chemical states of SIMFUELs, (Eu, U)O2+x and (Mo, Ru, Pd) alloys

    International Nuclear Information System (INIS)

    Some works were performed to examine the behavior of some fission products which are known to be soluble as oxides and insoluble as alloys in UO2 fuel matrix. For the purpose, the SIMFUELs, (Eu, U)O2+x were prepared in the reducing condition that was in a stream of pure H2 and for 4 hours at 1700 deg C. And insoluble metallic alloys composed of Mo-Ru-Pd were synthesized by the Argon arc melting method. The composition and some physicochemical properties of prepared SIMFUELs and alloys were measured by EPMA, SEM and XPS. (author). 6 refs., 2 tabs., 4 figs

  11. WO3-TiO2 monolithic catalysts for high temperature SCR of NO by NH3. Influence of preparation method on structural and physico-chemical properties, activity and durability

    International Nuclear Information System (INIS)

    The WO3-TiO2 catalysts with different WO3 loadings prepared by the coprecipitation method were investigated in comparison with those prepared by the conventional impregnation method for the activity and durability in the high temperature SCR of NO by NH3 and the structural and physico-chemical properties which were characterized by BET and XRD measurements, IR, Raman and XPS spectroscopies. The catalyst prepared by coprecipitation, as compared with that prepared by impregnation, was found to exhibit a higher SCR activity at high temperatures and also to possess a larger surface area, higher Broensted acidity and larger monolayer capacity of the support with WO3. Increasing the WO3 loading of the catalysts enhances the SCR activity and simultaneously increases the Broensted acidity. The observed improvement of SCR activity for the catalyst prepared by coprecipitation is mainly attributed to the higher Broensted acidity and the presence of the more highly dispersed WO3 species which is suggested by the larger monolayer capacity of ca. 13 μmol(W)/m2 and no crystalline WO3 on TiO2 detected with XRD at the high WO3 loading up to 40 wt.%. The catalyst with 20 wt.% WO3, as compared with that prepared by impregnation, was found to exhibit a better thermal durability at high temperatures from 550 to 600 C. The better durability is attributed to that the reduction of the surface area and the formation and subsequent growth of crystalline WO3 upon aging are more remarkably inhibited. (author)

  12. Development of Chemical Fingerprints for Quality Control of Xiong Ma Tang and its Related Preparations by High-Performance Liquid Chromatography.

    Science.gov (United States)

    Liu, Hengyan; Guo, Jiansheng; Li, Zhi; Zhang, Xiaodan; Liu, Xiangqian; Yook, Changsoo

    2016-02-01

    Xiong Ma Tang (XMT), one of the ancient herbal prescriptions, has been used in treatment of migraine disease. In this study, efficient high-performance liquid chromatographic fingerprints were developed for identification of 11 major marker components, named 1-(β-D-ribofuranosyl)-1H-1,2,4-triazone, gastrodin, ligustrazine, 3,4-bihydroxy benzaldehyde, p-hydroxy benzaldehyde, p-hydroxybenzoic acid, benzoic acid, vanillin, ferulic acid, caffeic acid and senkyunolide I, respectively, in XMT and three related preparations. The analysis of 11 marker compounds was carried out using a Kromasil C18 reserved-phase column (5 μm, 4.6 × 250 mm) and gradient elution with methanol and aqueous phosphoric acid (0.1%, v/v). The flow rate was 1.0 mL/min and the detector wavelength was set at 276 nm. Mean chromatograms and correlation coefficients of samples were calculated by the software "Similarity Evaluation System for Chromatographic Fingerprint of Traditional Chinese Medicine". The correlation coefficients of XMT and three related preparations ranged from 0.935 to 0.986, 0.909 to 0.949, 0.900 to 0.926 and 0.937 to 0.988, respectively. It was the first time 11 peaks of XMT and three related preparations were identified by comparing with standard compounds. These results have shown that the developed method was efficient for the quality evaluation of XMT and its related preparations. PMID:26472809

  13. Synthesis, characterization and study of magnetic, electrical and dielectric properties of La1-xDyxCo1-yFeyO3 nanoparticles prepared by wet chemical route

    Science.gov (United States)

    Choudhry, Qurshia; Azhar Khan, Muhammad; Nasar, Gulfam; Mahmood, Azhar; Shahid, Muhammad; Shakir, Imran; Farooq Warsi, Muhammad

    2015-11-01

    Dy3+ and Fe3+ co-doped LaCoO3 perovskite nanoparticles were prepared by chemical co-precipitation route. Structural elucidation was carried out by thermo gravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectroscopy. The data of all these characterization techniques confirmed the orthorhombic phase with particles size in the range of 20-60 nm. The magnetic parameters, DC-resistivity and dielectric properties were measured for La1-xDyxCo1-yFeyO3 nanoparticles. The purpose of all these application studies was to evaluate the prepared materials for practical applications. The substitution of Dy3+ and Fe3+ with La3+ and Co3+ respectively greatly influenced the magnetic, DC-resistivity and dielectric parameters.

  14. Analysis on chemical components changes in preparation process of cellulosic ethanol from poplar wood%杨木制备纤维乙醇过程中化学成分变化的分析

    Institute of Scientific and Technical Information of China (English)

    闫兴伟; 崔琳; 张林; 王芳; 陈茜文

    2015-01-01

    杨树是我国重要的速生树种。以杨木为原料制备生物乙醇是解决当今能源问题的一项新的尝试。对杨木原料蒸汽爆破预处理后以及菌处理后的化学成分及化学性质进行了测定分析。通过对比其化学成分(纤维素、木素、半纤维素、抽出物、灰分及蛋白质)的变化,研究了以杨木为原料制备生物乙醇生产过程中化学成分变化机理,旨在为指导杨木制备木质纤维乙醇的生产,并为发酵后副产物的回收再利用提供理论依据。%Poplar is an important fast-growing species in China. The preparation of bio-ethanol with poplar wood as the raw material is a new attempt to solve today’s energy problems. After steam-exploded pretreatment and then bacteria treatment to the poplar wood raw materials, the materials’ chemical composition and properties were measured and analyzed. Through contrasting the changes of the materials’ chemical composition(cellulose, lignin, hemicelluloses, extracts, ash and protein), the mechanism of chemical change of the tested materials in the bioethanol production process prepared from poplar wood was studied, the surplus product contained 64.07%lignin, 6.78% cellulose and 6.88% hemicellulose. The results provide a theoretical basis for guiding the preparation of poplar wood cellulosic ethanol production, and the subsequent recycling of fermentation by-products.

  15. Physical and tribological properties of a-Si1-xCx:H coatings prepared by r.f. plama-assisted chemical vapour deposition

    International Nuclear Information System (INIS)

    A-Si1-xCx:H films deposited by r.f. plasma-assisted chemical vapour deposition were studied as a function of their composition. The friction and wear properties were investigated with the help of a conventional ball-on-disc apparatus. These results are correlated with chemical (Si/C atomic ratio) and structural (Raman and infrared spectroscopy) properties. The friction coefficient in a humid ambient atmosphere changes markedly with the carbon fraction and reaches a value as low as 0.05 for coatings with 70 to 90 at.% C. The carbon-rich films consist of diamond-like carbon with silicon. (orig.)

  16. The effect of thermal annealing on the properties of alumina films prepared by metal organic chemical vapour deposition at atmospheric pressure

    NARCIS (Netherlands)

    Haanappel, V.A.C.; Corbach, van H.D.; Fransen, T.; Gellings, P.J.

    1994-01-01

    Thin films deposited at 330°C by metal organic chemical vapour deposition on stainless steel, type AISI 304, were annealed in a nitrogen atmosphere for 1, 2 and 4 h at 600, 700 and 800°C. The film properties, including the protection of the underlying substrate against high temperature corrosion, th

  17. Properties of alumina films prepared by metal-organic chemical vapour deposition at atmospheric pressure in hte presence of small amounts of water

    NARCIS (Netherlands)

    Haanappel, V.A.C.; Rem, J.B.; Corbach, van H.D.; Fransen, T.; Gellings, P.J.

    1995-01-01

    Thin alumina films were deposited on stainless steel, type AISI 304. The deposition process was carried out in nitrogen with low partial pressures of water (0–2.6 × 10−2 kPa (0−0.20 mmHg)) by metal-organic chemical vapour deposition (MOCVD) with aluminium-tri-sec-butoxide (ATSB) as the precursor. Al

  18. The effect of MgO nano-particles on Bi-2223 high temperature superconductors prepared by chemical sol-gel method

    Directory of Open Access Journals (Sweden)

    M. Eshraghi

    2008-12-01

    Full Text Available  In this paper, two La0/8sr0/2mno3 samples, isotropic (press without magnetic field and anisotropic (press with magnetic field have been prepared. Then we have investigated structural, magnetic and magnetotransport properties of these samples using XRD, SEM, Ac susceptibility and magnetoresistance measurements. These studies show that a magnetic property of anisotropic sample is improved and magnetoresistance is decreased.

  19. New low-temperature preparations of some simple and mixed co and ni dispersed sulfides and their chemical behavior in reducing atmosphere.

    Science.gov (United States)

    Bezverkhyy, I; Danot, M; Afanasiev, P

    2003-03-10

    A series of simple (CoS(2), Co(9)S(8), NiS(2), NiS, Ni(3)S(2)) and mixed sulfides (NiCo(2)S(4), Ni(0.33)Co(0.67)S(2), Ni(3)Co(6)S(8), CuCo(2)S(4), Cu(0.33)Co(0.67)S(2)) was prepared using low-temperature procedures. To obtain the mixed sulfides, the mixtures of the solutions of the corresponding salts were precipitated by Na(2)S and then heated in a sulfiding atmosphere at 300 degrees C. It has been found that the product phase composition depends on the sulfiding atmosphere. Using a H(2)S/Ar mixture leads to pyrite type sulfides, whereas treatment in H(2)S/H(2) flow allowed the preparation of Ni-Co and Cu-Co thiospinels. The as prepared highly dispersed single-phase materials were characterized by X-ray powder diffraction, scanning electron microscopy, temperature-programmed reduction (TPR), elemental analysis, and BET surface area measurements.

  20. Preparation,inentification and application of pyrenebutyric acid-silica and diphenylanthracene-silica reagent on fiber-optic chemical sensor

    Institute of Scientific and Technical Information of China (English)

    LI Xin-xia; CHEN Jian

    2003-01-01

    @@ 1 Introduction Two new fiber-optic chemical sensor based on multiple fluorescence quenching is described. The reagent phases of the sensors are stable in organic solvent. The first reagent phase was constructed by covalent bonding pyrenebutyric acid (PBA) to the surface of glass (PBA-SiO2). It was identified by IR spectrum, fluorescence spectra and TGA analysis. And it can determine Rutin in ethanol.

  1. Structural and XPS studies of PSi/TiO{sub 2} nanocomposites prepared by ALD and Ag-assisted chemical etching

    Energy Technology Data Exchange (ETDEWEB)

    Iatsunskyi, Igor, E-mail: yatsunskiy@gmail.com [NanoBioMedical Centre, Adam Mickiewicz University, 85 Umultowska Str., 61-614 Poznan (Poland); Kempiński, Mateusz [NanoBioMedical Centre, Adam Mickiewicz University, 85 Umultowska Str., 61-614 Poznan (Poland); Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614 (Poland); Nowaczyk, Grzegorz; Jancelewicz, Mariusz [NanoBioMedical Centre, Adam Mickiewicz University, 85 Umultowska Str., 61-614 Poznan (Poland); Pavlenko, Mykola [Department of Experimental Physics, Odessa National I.I. Mechnikov University, 42, Pastera Str., 65023 Odessa (Ukraine); Załęski, Karol [NanoBioMedical Centre, Adam Mickiewicz University, 85 Umultowska Str., 61-614 Poznan (Poland); Jurga, Stefan [NanoBioMedical Centre, Adam Mickiewicz University, 85 Umultowska Str., 61-614 Poznan (Poland); Department of Macromolecular Physics, Adam Mickiewicz University, Umultowska 85, 61-614 Poznan (Poland)

    2015-08-30

    Highlights: • Porous silicon/TiO{sub 2} nanocomposites have been investigated. • Morphology and chemical composition of PSi/TiO{sub 2} nanocomposites were established. • Valence-band XPS maximums for PSi/TiO{sub 2} nanocomposites were found and analyzed. - Abstract: PSi/TiO{sub 2} nanocomposites fabricated by atomic layer deposition (ALD) and metal-assisted chemical etching (MACE) were investigated. The morphology and phase structure of PSi/TiO{sub 2} nanocomposites were studied by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM) with an energy dispersive X-ray spectroscopy (EDX) and Raman spectroscopy. The mean size of TiO{sub 2} nanocrystals was determined by TEM and Raman spectroscopy. X-ray photoelectron spectroscopy (XPS) was used to analyze the chemical elemental composition by observing the behavior of the Ti 2p, O 1s and Si 2p lines. TEM, Raman spectroscopy and XPS binding energy analysis confirmed the formation of TiO{sub 2} anatase phase inside the PSi matrix. The XPS valence band analysis was performed in order to investigate the modification of PSi/TiO{sub 2} nanocomposites electronic structure. Surface defects states of Ti{sup 3+} at PSi/TiO{sub 2} nanocomposites were identified by analyzing of XPS valence band spectra.

  2. Preparation of Iron-Nitride Magnetic Fluid by Vapor-Liquid Chemical Reaction%气-液化学反应制备氮化铁磁性液体

    Institute of Scientific and Technical Information of China (English)

    郭广生; 王志华; 余实; 杨福明

    2000-01-01

    通过氨气和五羰基铁之间的气-液化学反应,制备出了稳定的氮化铁磁性液体. 较为详细地研究了原料的配比、反应温度、表面活性剂的种类及用量等实验参数对产品性能的影响. 利用XRD、TEM和振动样品磁强计(VSM)等技术对产品?的化学组成、固体粒子的粒径、晶型及磁性能进行了测定. 制备的磁性液体具有较高的饱和磁化强度,达到0.134T.%This paper introduced the preparation of stable iron-nitride magnetic fluid by vapor-liquid chemical reaction between iron carbonyl and ammonia. The effects of experiment parameters, such as reactant proportion, reaction temperature, the type and the dosage of the surfactant on product properties were studied in detail. X-ray diffraction(XRD), transmission electron microscope(TEM) and vibrating-sample magnetometer(VSM) were carried out to measure the chemical structure, the crystal style and the magnetic property. The prepared magnetic fluids have high performances with respect to saturation magnetization, up to 0.134T.

  3. Studies on Y{sub 2}O{sub 3}:Eu phosphor with different particle size prepared by wet chemical method

    Energy Technology Data Exchange (ETDEWEB)

    Muresan, Laura, E-mail: laura_muresan2003@yahoo.co [Raluca Ripan Institute for Research in Chemistry, Fantanele 30, 400294 Cluj-Napoca (Romania); Popovici, Elisabeth Jeanne; Imre-Lucaci, Florica; Grecu, Rodica [Raluca Ripan Institute for Research in Chemistry, Fantanele 30, 400294 Cluj-Napoca (Romania); Indrea, Emil [National Institute for R and D of Isotopic and Molecular Technologies, 400295, Cluj-Napoca Romania (Romania)

    2009-08-26

    Europium activated yttrium oxide phosphors were prepared by reagent simultaneous addition technique, using oxalic acid as precipitating reagent. The aim of the paper is to establish the flux influence and thermal regime on photoluminescence and morpho-structural characteristics of phosphor powders. In this respect different mineralising agents such as sodium/lithium carbonate, sodium tetraborate ans sodium pyrophosphate were used during the thermal synthesis stage. Thermal analysis, X-ray diffraction, scanning electron microscopy, infrared spectroscopy and photoluminescence measurements were used to investigate precursor and phosphor powders. The correlation between the phosphor properties and precursor quality enabled us to select the optimal synthesis conditions.

  4. Synthesis, characterization and study of magnetic, electrical and dielectric properties of La1−xDyxCo1−yFeyO3 nanoparticles prepared by wet chemical route

    International Nuclear Information System (INIS)

    Dy3+ and Fe3+ co-doped LaCoO3 perovskite nanoparticles were prepared by chemical co-precipitation route. Structural elucidation was carried out by thermo gravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectroscopy. The data of all these characterization techniques confirmed the orthorhombic phase with particles size in the range of 20–60 nm. The magnetic parameters, DC-resistivity and dielectric properties were measured for La1−xDyxCo1−yFeyO3 nanoparticles. The purpose of all these application studies was to evaluate the prepared materials for practical applications. The substitution of Dy3+ and Fe3+ with La3+ and Co3+ respectively greatly influenced the magnetic, DC-resistivity and dielectric parameters. - Highlights: • La1−xDyxCo1−yFeyO3 nanoparticles were prepared in the range 20–60 nm. • 12 Fold increase in DC resistivity achieved for La0.40Dy0.60Co0.40Fe0.60O3. • Paramagnetic to ferromagnetic behavior was observed for La1−xDyxCo1−yFeyO3 nanoparticles

  5. Chem-prep PZT95/5 for neutron generator applications : the effect of pore former type and density on the depoling behavior of chemically prepared PZT 95/5 ceramics.

    Energy Technology Data Exchange (ETDEWEB)

    Lockwood, Steven John; Scofield, Timothy W.; Yang, Pin; Voigt, James A.; Tuttle, Bruce Andrew; Moore, Roger Howard

    2003-10-01

    The hydrostatically induced ferroelectric(FE)-to-antiferroelectric(AFE) phase transformation for chemically prepared niobium modified PZT 95/5 ceramics was studied as a function of density and pore former type (Lucite or Avicel). Special attention was placed on the effect of different pore formers on the charge release behavior associated with the FE-to-AFE phase transformation. Within the same density range (7.26 g/cm3 to 7.44 g/cm3), results showed that ceramics prepared with Lucite pore former exhibit a higher bulk modulus and a sharper polarization release behavior than those prepared with Avicel. In addition, the average transformation pressure was 10.7% greater and the amount of polarization released was 2.1% higher for ceramics with Lucite pore former. The increased transformation pressure was attributed to the increase of bulk modulus associated with Lucite pore former. Data indicated that a minimum volumetric transformational strain of -0.42% was required to trigger the hydrostatically induced FE-to-AFE phase transformation. This work has important implications for increasing the high temperature charge output for neutron generator power supply units.

  6. Preparation and characterization of Pd/Al{sub 2}O{sub 3} and Pd nanoparticles as standardized test material for chemical and biochemical studies of traffic related emissions

    Energy Technology Data Exchange (ETDEWEB)

    Leopold, K. [Technische Universitaet Muenchen, Arbeitsgruppe fuer Analytische Chemie, Lichtenbergstrasse 4, D-85747 Garching (Germany)], E-mail: kerstin.leopold@lrz.tum.de; Maier, M.; Schuster, M. [Technische Universitaet Muenchen, Arbeitsgruppe fuer Analytische Chemie, Lichtenbergstrasse 4, D-85747 Garching (Germany)

    2008-05-01

    Palladium model particles similar to those emitted from catalytic car exhaust converters were prepared and characterized with the intention of providing a standardized material for investigations of the chemical behavior and bioavailability of traffic related Pd emissions. Two series of Pd particles were prepared and characterized in detail: Pd nanoparticles (2-4 nm) dispersed on aluminum oxide particles of a diameter range between 0.1 to 30 {mu}m and 'Pd-only' nanoparticles of 5-10 nm in diameter. The Pd/{alpha}-Al{sub 2}O{sub 3} particles are very similar to particles emitted from catalytic converters by mechanical abrasion. The Pd-only particles are useful e.g. for exposure studies in which the presence of aluminum could lead to interferences when studying biological and biochemical effects. The sample preparation procedure of both series was optimized in order to achieve elemental particles with proper sizes and a narrow size distribution. The obtained particles were characterized by transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), selective area diffraction (SAD), laser granulometry and graphite furnace atomic absorption spectrometry (GFAAS) for the measurement of Pd concentrations.

  7. Physico-Chemical Characterization and Interfacial Electrochemical Properties of Nanoparticles of Anatase-TiO2 Prepared by the Sol-Gel Method

    Directory of Open Access Journals (Sweden)

    Ikram Daou

    2013-07-01

    Full Text Available In this work, we prepared by the sol-gel method titanium dioxide nanoparticles having a large specific area (SBET = 218 m2/g. The isotherm of N2 adsorption-desorption at 77K revealed that it concerns a mesoporous solid with a maximum pore diameter of 43 Å. The X-ray diffraction showed that the solid is constituted of the anatase phase. The transmission electron microscopy revealed us that the synthesized grains of TiO2 are of nanometric sizes (diameter between 8 and 20 nm and manifest under agglomerated shape. The study of its solubility in dispersing phase, by conductometric titrations, showed that the prepared solid is totally insoluble in all the domain of the studied pH. The measured inter-facial electrochemical properties, based on the isotherms of ionic adsorption and the conductometric titrations, are: the point of zero charge found equal to 6,2±0,1, the total number of sites of surface found equal to 5,8 OH/nm2 and the nature of action of the dispersed phase on the dispersing phase which is found organizer of the structure of water. Besides, the difference of the ionizationconstants pK is found superior to 4 for all the adsorbed ions and the constants of surface complexation are independent from the nature of the adsorbed ion.

  8. Multilayer MoS2 prepared by one-time and repeated chemical vapor depositions: anomalous Raman shifts and transistors with high ON/OFF ratio

    Science.gov (United States)

    Wu, Chong-Rong; Chang, Xiang-Rui; Chang, Shu-Wei; Chang, Chung-En; Wu, Chao-Hsin; Lin, Shih-Yen

    2015-11-01

    We show that multilayer molybdenum disulfide (MoS2) grown with the chemical vapor deposition (CVD) may exhibit quite distinct behaviors of Raman shifts from those of exfoliated ones. The anomalous Raman shifts depend on CVD growth modes and are attributed to the modified dielectric screening and interlayer coupling of MoS2 in various growth conditions. With repeated CVD growths, we demonstrated the precise control over the layer number of MoS2. A decently large drain current, high ON/OFF ratio of 105, and enhanced field-effect mobility can be achieved in transistors fabricated on the six-layer MoS2.

  9. Low temperature carrier transport study of monolayer MoS{sub 2} field effect transistors prepared by chemical vapor deposition under an atmospheric pressure

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xinke, E-mail: xkliu@szu.edu.cn, E-mail: wujing026@gmail.com; He, Jiazhu; Tang, Dan; Lu, Youming; Zhu, Deliang; Liu, Wenjun; Cao, Peijiang; Han, Sun [College of Materials Science and Engineering, Shenzhen Engineering Laboratory for Advanced Technology of Ceramics, Nanshan District Key Lab for Biopolymer and Safety Evaluation, Shenzhen University, 3688 Nanhai Ave, Shenzhen 518060 (China); Liu, Qiang; Wen, Jiao; Yu, Wenjie [State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, CAS, 865 Chang Ning Road, Shanghai 200050 (China); Liu, Wenjun [State Key Laboratory of ASIC and System, Department of Microelectronics, Fudan University, 220 Handan Road, Shanghai 200433 (China); Wu, Jing, E-mail: xkliu@szu.edu.cn, E-mail: wujing026@gmail.com [Department of Physics, National University of Singapore, 21 Lower Kent Ridge Road, 117576 Singapore (Singapore); He, Zhubing [Department of Materials Science and Engineering, South University of Science and Technology of China, 1088 Xueyuan Road, Shenzhen 518055 (China); Ang, Kah-Wee [Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, 117583 Singapore (Singapore)

    2015-09-28

    Large size monolayer Molybdenum disulphide (MoS{sub 2}) was successfully grown by chemical vapor deposition method under an atmospheric pressure. The electrical transport properties of the fabricated back-gate monolayer MoS{sub 2} field effect transistors (FETs) were investigated under low temperatures; a peak field effect mobility of 59 cm{sup 2}V{sup −1}s{sup −1} was achieved. With the assist of Raman measurement under low temperature, this work identified the mobility limiting factor for the monolayer MoS{sub 2} FETs: homopolar phonon scattering under low temperature and electron-polar optical phonon scattering at room temperature.

  10. Low temperature carrier transport study of monolayer MoS2 field effect transistors prepared by chemical vapor deposition under an atmospheric pressure

    International Nuclear Information System (INIS)

    Large size monolayer Molybdenum disulphide (MoS2) was successfully grown by chemical vapor deposition method under an atmospheric pressure. The electrical transport properties of the fabricated back-gate monolayer MoS2 field effect transistors (FETs) were investigated under low temperatures; a peak field effect mobility of 59 cm2V−1s−1 was achieved. With the assist of Raman measurement under low temperature, this work identified the mobility limiting factor for the monolayer MoS2 FETs: homopolar phonon scattering under low temperature and electron-polar optical phonon scattering at room temperature

  11. Physical and Chemical Properties of TiOxNy Prepared by Low-Temperature Oxidation of Ultrathin Metal Nitride Directly Deposited on SiO2

    Institute of Scientific and Technical Information of China (English)

    HAN Yue-Ping; HAN Yan

    2009-01-01

    Physical and chemical properties of titanium oxynitride (TiOxNy) formed by low-temperature oxidation of titanium nitride (TIN) layer are investigated for advanced metal-oxide--semiconductor (MOS) gate dielectric application.TiOx Ny exhibits polycrystalline properties after the standard thermal process for MOS device fabrication,showing the preferred orientation at [200].Superior electrical properties of TiOxNy can be maintained before and after the annealing,probably due to the nitrogen incorporation in the oxide bulk and at the interface.Naturally formed transition layer between TiOxNy and SiO2 is also confirmed.

  12. Study of the crystallographic phase change on copper (I) selenide thin films prepared through chemical bath deposition by varying the pH of the solution

    Science.gov (United States)

    Sandoval-Paz, M. G.; Rodríguez, C. A.; Porcile-Saavedra, P. F.; Trejo-Cruz, C.

    2016-07-01

    Copper (I) selenide thin films with orthorhombic and cubic structure were deposited on glass substrates by using the chemical bath deposition technique. The effects of the solution pH on the films growth and subsequently the structural, optical and electrical properties of the films were studied. Films with orthorhombic structure were obtained from baths wherein both metal complex and hydroxide coexist; while films with cubic structure were obtained from baths where the metal hydroxide there is no present. The structural modifications are accompanied by changes in bandgap energy, morphology and electrical resistivity of the films.

  13. Dielectric properties and X-ray photoelectron spectroscopic studies of niobium oxide thin films prepared by direct liquid injection chemical vapor deposition method

    International Nuclear Information System (INIS)

    Niobium oxide thin films were grown by direct liquid injection chemical vapor deposition using Nb(OC2H5)5 precursor. Influence of reactant's molar ratios [oxygen:Nb(OC2H5)5] and deposition temperatures on films properties such as growth rate, stoichiometry, crystal structure, morphology, dielectric constant and leakage current were studied. Films start crystallizing above 340 °C in O2 atmosphere and become crystalline at 400 °C. The surface roughness of weakly crystalline and crystalline films was significantly affected by deposition temperatures and reactant's molar ratios. It was found that decrease in surface roughness improved leakage current. X-ray photoelectron spectroscopic studies showed that films were in different oxidation states (Nb2+, Nb4+ and Nb5+). The dielectric constants of films were improved by increasing oxygen ratios. At ratio (150:1), the film showed high dielectric constant value (47) at 340 °C and leakage current density of 2.0 × 10−5 A/cm2 (at 3 V). - Highlights: • High dielectric constant (47) of Nb2O5 thin film with chemical vapor deposition • The change in morphology as a function of growth temperature and O2 molar ratio • A stoichiometric Nb2O5 phase and smooth surface show better electrical properties

  14. Comparison of two chemical cleavage methods for preparation of a truncated form of recombinant human insulin-like growth factor I from a secreted fusion protein.

    Science.gov (United States)

    Forsberg, G; Baastrup, B; Brobjer, M; Lake, M; Jörnvall, H; Hartmanis, M

    1989-12-01

    We have produced a naturally occurring variant of human insulin-like growth factor I, truncated by three amino acids at the amino terminus. The polypeptide is obtained as a fusion protein in Escherichia coli. The fusion partner is a synthetic IgG-binding peptide. During fermentation the fusion protein is secreted into the medium, and is purified on IgG--Sepharose prior to cleavage. Two different genes for the fusion protein were used, allowing chemical cleavage at either a tryptophan linker or a methionine linker between the fusion partner and the growth factor, using N-chlorosuccinimide (NCS) or cyanogen bromide (CNBr) respectively. A partial CNBr cleavage yielded the native peptide, whereas the NCS cleavage yielded a product in which the single methionine had been oxidized to the sulfoxide. The forms from both cleavage methods exhibited biological activity and were characterized after purification to homogeneity. Both cleavage methods gave products having correct N- and C-terminal ends. The purified product had a biological activity equal to that of corresponding material from natural sources, 15 000 U/mg. Modified forms of truncated IGF-I were also identified, purified and characterized. Modifications such as proteolysis and misincorporation of norleucine for methionine occurred during biosynthesis, while oxidation of methionine took place during both fermentation and chemical cleavage. PMID:2696476

  15. Synthesis and photocatalytic application of α-Fe2O3/ZnO fine particles prepared by two-step chemical method

    Directory of Open Access Journals (Sweden)

    Patij Shah

    2013-06-01

    Full Text Available Composite iron oxide-Zinc oxide (α-Fe2O3/ZnO was synthesized by two-step method: in the first one step uniform α-Fe2O3 particles were prepared through a hydrolysis process of ferric chloride at 80 °C. In the second step, the ZnO particles were included in the α-Fe2O3 particles by a zinc acetate [Zn(Ac2·2H2O] assisted hydrothermal method at low temperature (90°C±C. The α-Fe2O3 and ZnO phases were identified by XRD, energy dispersive X-ray analysis (EDX. The photoreactivities of α-Fe2O3/ZnO nanoparticles under UV irradiation were quantified by the degradation of formaldehyde.

  16. Effect of annealing temperature on the structural–microstructural and electrical characteristics of thallium bearing HTSC films prepared by chemical spray pyrolysis technique

    Indian Academy of Sciences (India)

    K K Verma; R S Tiwari; O N Srivastava

    2005-04-01

    In order to get good quality reproducible films of Tl : HTSC system, we have studied the different annealing conditions to finally achieve the optimized annealing condition. In the present investigation, Tl–Ca–Ba–Cu–O superconducting films have been prepared on YSZ (100) and MgO (100) single crystal substrates via precursor route followed by thallination. The post deposition heat treatments of the precursor films were carried out for various annealing temperatures (870°C, 890°C) and durations (1 and 2 min). The optimized thallination procedure occurred at 870°C for 2 min into good quality films with c ( = 0) ∼ 103 K for YSZ and c ( = 0) ∼ 98 K for MgO substrates, respectively. Further we have correlated the structural/microstructural characteristics of the films.

  17. KANJI: AN AYURVEDIC FERMENTATIVE PREPARATION

    OpenAIRE

    Santhosh B; Jadar P. G.; Nageswara Rao

    2012-01-01

    Kanji – A unique Ayurvedic fermentative preparation was prepared as per the textual reference Rasayanasara which is mainly indicated for the Shodhana (purification) of Metals and also for various mercurial processing. But Kanji by this reference is rarely prepared and used. Hence, the pharmaceutical and preliminary physico-chemical findings of this Kanji are reported in this paper. The fermentation process started on 7th day and completed on 31st day. The prepared Kanji was golden brown color...

  18. Preparation and physico-chemical study of nitroxide radicals. Isotopic marking with carbon 13 and deuterium; Preparations et etudes physico-chimiques de radicaux nitroxydes. Marquage isotopique au carbone 13 et au deuterium

    Energy Technology Data Exchange (ETDEWEB)

    Chapelet-Letourneux, G. [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1967-07-01

    N-t-butyl-N-phenyl nitroxide is obtained by: a) action of t-butyl-magnesium chloride on nitrobenzene, or of phenyl-magnesium bromide on nitro-t-butane, b) oxidation of N-t-butyl-N-phenylhydroxylamine, c) oxidation of N-t-butylaniline. In these latter two cases, it has been possible to isolate the pure radical and to study it using UV, IR and EPR. It decomposes to give N-t-butylaniline and the N-oxide of N-t-butyl-p-quinon-imine. The action of peracids such as p-nitro-perbenzoic or m-chloro-perbenzoic acids on amines or hydroxylamines leads to the formation of stable or unstable nitroxide radicals easily observable by EPR. Finally, with a view to obtaining definite values for the coupling between the free electron of a nitroxide and carbon 13, the preparation of such radicals marked with {sup 13}C in the {alpha} or {beta} position of the nitroxide function has been carried out. The coupling with an {alpha} carbon 13 is negative and does not appear to vary with the spin density on the nitrogen. The interaction with the p nuclei of the nitrogen depends on the nature of the substituents: the two benzyl protons have a hyperfine splitting a{sub H} which is always less than that of the ethyl. On the other hand, the {sup 13}C coupling is greater in the first case. The usually adopted conformations for the compounds having the carbonyl group cannot account for the observed values of the {beta} couplings. (author) [French] Le N-t-butyl-N-phenyl nitroxyde est obtenu par: a) action du chlorure de t-butylmagnesium sur le nitrobenzene, ou du bromure de phenylmagnesium sur le nitro-t-butane, b) oxydation de la N-t-butyl-N-phenylhydroxylamine, c) oxydation de la N-t-butylaniline. Dans ces deux derniers cas, le radical a pu etre isole pur et etudie par UV, IR et RPE. Il se decompose en N-t-butylaniline et N-oxyde de N-t-butyl-p-quinonimine. L'action de peracides (p-nitroperbenzoique ou m-chloroperbenzoique) sur des amines ou des hydroxylamines conduit a des radicaux nitroxydes

  19. Synthesis and magnetic properties of cobalt ferrite (CoFe{sub 2}O{sub 4}) nanoparticles prepared by wet chemical route

    Energy Technology Data Exchange (ETDEWEB)

    Maaz, K. [Department of Physics, Quaid-i-Azam University, Islamabad (Pakistan); Mumtaz, Arif [Department of Physics, Quaid-i-Azam University, Islamabad (Pakistan)]. E-mail: arif@qau.edu.pk; Hasanain, S.K. [Department of Physics, Quaid-i-Azam University, Islamabad (Pakistan); Ceylan, Abdullah [Department of Physics and Astronomy, University of Delaware, Newark (United States)

    2007-01-15

    Magnetic nanoparticles of cobalt ferrite have been synthesized by wet chemical method using stable ferric and cobalt salts with oleic acid as the surfactant. X-ray Diffraction (XRD) and Transmission Electron Microscope (TEM) confirmed the formation of single-phase cobalt ferrite nanoparticles in the range 15-48 nm depending on the annealing temperature and time. The size of the particles increases with annealing temperature and time while the coercivity goes through a maximum, peaking at around 28 nm. A very large coercivity (10.5 kOe) is observed on cooling down to 77 K while typical blocking effects are observed below about 260 K. The high field moment is observed to be small for smaller particles and approaches the bulk value for large particles.

  20. Characterization of thin TiO{sub 2} films prepared by plasma enhanced chemical vapour deposition for optical and photocatalytic applications

    Energy Technology Data Exchange (ETDEWEB)

    Sobczyk-Guzenda, A., E-mail: asobczyk@p.lodz.p [Institute of Materials Science and Engineering, Technical University of Lodz, Stefanowskiego 1, 90-924 Lodz (Poland); Gazicki-Lipman, M.; Szymanowski, H.; Kowalski, J. [Institute of Materials Science and Engineering, Technical University of Lodz, Stefanowskiego 1, 90-924 Lodz (Poland); Wojciechowski, P.; Halamus, T. [Department of Molecular Physics, Technical University of Lodz, Stefanowskiego 1, 90-924 Lodz (Poland); Tracz, A. [Centre for Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363 Lodz (Poland)

    2009-07-31

    Thin titanium oxide films were deposited using a radio frequency (RF) plasma enhanced chemical vapour deposition method. Their optical properties and thickness were determined by means of ultraviolet-visible absorption spectrophotometry. Films of the optical parameters very close to those of titanium dioxide have been obtained at the high RF power input. Their optical quality is high enough to allow for their use in a construction of stack interference optical filters. At the same time, these materials exhibit strong photocatalytic effects. The results of structural analysis, carried out by Raman Shift Spectroscopy, show that the coatings posses amorphous structure. However, Raman spectra of the same films subjected to thermal annealing at 450 {sup o}C disclose an appearance of a crystalline form, namely that of anatase. Surface morphology of the films has also been characterized by Atomic Force Microscopy revealing granular, broccoli-like topography of the films.

  1. Preparation of AlGaN/GaN Heterostructures on Sapphire Using Light Radiation Heating Metal-Organic Chemical Vapor Deposition at Low Pressure

    Institute of Scientific and Technical Information of China (English)

    ZHOU Yu-Gang; ZHENG You-Dou; SHEN Bo; ZHANG Rong; LI Wei-Ping; CHEN Peng; CHEN Zhi-Zhong; GU Shu-Lin; SHI Yi; Z. C. Huang

    2000-01-01

    AlGaN/GaN heterostructures on sapphire substrate were fabricated by using light radiation heating metalor ganic chemical vapor deposition. Photoluminescence excitation spectra show that there are two abrupt slopes corresponding to the absorption edges of AlGaN and GaN, respectively. X-ray diffraction spectra clearly exhibit the GaN (0002), (0004), and A1GaN (0002), (0004) diffraction peaks, and no diffraction peak other than those from the GaN {0001} and A1GaN {0001} planes is found. Reciprocal space mapping indicates that there is no tilt between the AlGaN layer and the GaN layer. All results also indicate that the sample is of sound quality and the Al composition in the AlGaN layer is of high uniformity.

  2. Influence of double AlN buffer layers on the qualities of GaN films prepared by metal-organic chemical vapour deposition

    Institute of Scientific and Technical Information of China (English)

    Lin Zhi-Yu; Hao Yue; Zhang Jin-Cheng; Zhou Hao; Li Xiao-Gang; Meng Fan-Na; Zhang Lin-Xia; Ai Shan; Xu Sheng-Rui; Zhao Yi

    2012-01-01

    In this paper we report that the GaN thin film is grown by metal-organic chemical vapour deposition on a sapphire (0001) substrate with double AlN buffer layers.The buffer layer consists of a low-temperature (LT) AlN layer and a high-temperature (HT) AlN layer that are grown at 600 ℃ and 1000 ℃,respectively.It is observed that the thickness of the LT-AlN layer drastically influences the quality of GaN thin film,and that the optimized 4.25-min-LT-AlN layer minimizes the dislocation density of GaN thin film.The reason for the improved properties is discussed in this paper.

  3. Compositional and physico-optical characterization of 0-5% Al-doped zinc oxide films prepared by chemical spray pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Romero, R; Lopez-Ibanez, R; Ramos-Barrado, J R; Martin, F; Leinen, D [Laboratorio de Materiales y Superficie (Unidad Asociada al CSIC), Dpto. Fisica Aplicada I and Dpto. IngenierIa Quimica, Universidad de Malaga, E-29071 Malaga (Spain); Dalchiele, E A, E-mail: dietmar@uma.e [Instituto de Fisica, Facultad de IngenierIa, Universidad de la Republica, Herrera y Reissig 565, C.C. 30, 11000 Montevideo (Uruguay)

    2010-03-10

    Highly transparent polycrystalline Al-doped ZnO thin films were deposited in open atmosphere by chemical spray pyrolysis on fused silica and glass substrates at 623 K. The influence of Al doping, 0 to 5%, was studied. XPS results revealed a linear relationship between Al content in the precursor solutions and Al content in the films. XPS depth profiling showed that any carbon contamination is restricted to the uppermost surface of the films. Optical transmission measurements revealed an increasing number of dispersion centres as well as a band gap shift to higher values with increasing Al content in the films. At fixed Al concentration, the comparison of the absorption coefficient for increasing film thickness showed that the films are very homogeneous, not changing their materials properties such as absorption coefficient and band gap.

  4. Low temperature deposition and effect of plasma power on tin oxide thin films prepared by modified plasma enhanced chemical vapor deposition

    International Nuclear Information System (INIS)

    This work presents low temperature (200 and 300 deg. C) thin film deposition of tin oxide (SnO2) using modified plasma enhanced chemical vapor deposition as a function of radio frequency power (100 - 500 W). Stannic chloride (SnCl4) was used as precursor and oxygen (O2, 300 SCCM) as reactant gas. Fine granular morphology was observed with tetragonal rutile structure grown along the [110] direction, at all the deposition conditions. Higher plasma power resulted in smoother morphology, improved crystallinity, and enhanced conductivity. Electrical resistivity value of as low as ∼0.01 Ω cm was obtained at the deposition temperature of 300 deg. C and 250 W of plasma power

  5. 甘氨酸亚铁制备及热化学性质研究%Preparation of Ferrous Glycinate and Research on Hot Chemical Properties

    Institute of Scientific and Technical Information of China (English)

    毛玉娥; 雷克林

    2011-01-01

    研究了固相研磨法、固相催化研磨法和熔融法三种实验条件下,甘氨酸与硫酸亚铁铵以物质的量之比2:1反应得到二价亚铁与甘氨酸的配合物.通过对配合物进行红外光谱表征和定量分析,得到二价亚铁配合物的组成为【Fe(Gly)2].最后,根据熔解一量热法的基本操作条件,设计了热化学循环,测量了反应物和产物的标准摩尔溶解焓,结合热化学原理,测定了甘氨酸亚铁的标准摩尔生成焓.%This topic mainly researches the reaction of glycine and ammonium ferrous sulphate at the ratio of the amount of 2:1 to get the complexes of bivalent ferrous and glycine through solid-phase grinding method, solid phase catalysis grinding method and melting method. Through IR characterization and quantitative analysis, we are sure that the composition of ferrous complexes is [Fe(Gly)2]. Finally, according to the basic operation conditions of Dissolve- Quantity hot method, we designed the thermal and chemical circulation, and measured the standards Moore of reactant and product, which is combined with hot dissolving enthalpy chemical principle; we estimate the standard Moore of ferrous glycinate.

  6. Amorphous silicon carbon films prepared by hybrid plasma enhanced chemical vapor/sputtering deposition system: Effects of r.f. power

    Energy Technology Data Exchange (ETDEWEB)

    Rashid, Nur Maisarah Abdul, E-mail: nurmaisarahrashid@gmail.com [Low Dimensional Materials Research Centre, Department of Physics, University of Malaya, 50603 Kuala Lumpur (Malaysia); Ritikos, Richard; Othman, Maisara; Khanis, Noor Hamizah; Gani, Siti Meriam Ab. [Low Dimensional Materials Research Centre, Department of Physics, University of Malaya, 50603 Kuala Lumpur (Malaysia); Muhamad, Muhamad Rasat [Chancellery Office, Multimedia University, Jalan Multimedia, 63100 Cyberjaya, Selangor (Malaysia); Rahman, Saadah Abdul, E-mail: saadah@um.edu.my [Low Dimensional Materials Research Centre, Department of Physics, University of Malaya, 50603 Kuala Lumpur (Malaysia); Chancellery Office, Multimedia University, Jalan Multimedia, 63100 Cyberjaya, Selangor (Malaysia)

    2013-02-01

    Silicon carbon films were deposited using a hybrid radio frequency (r.f.) plasma enhanced chemical vapor deposition (PECVD)/sputtering deposition system at different r.f. powers. This deposition system combines the advantages of r.f. PECVD and sputtering techniques for the deposition of silicon carbon films with the added advantage of eliminating the use of highly toxic silane gas in the deposition process. Silicon (Si) atoms were sputtered from a pure amorphous silicon (a-Si) target by argon (Ar) ions and carbon (C) atoms were incorporated into the film from C based growth radicals generated through the discharge of methane (CH{sub 4}) gas. The effects of r.f. powers of 60, 80, 100, 120 and 150 W applied during the deposition process on the structural and optical properties of the films were investigated. Raman spectroscopic studies showed that the silicon carbon films contain amorphous silicon carbide (SiC) and amorphous carbon (a-C) phases. The r.f. power showed significant influence on the C incorporation in the film structure. The a-C phases became more ordered in films with high C incorporation in the film structure. These films also produced high photoluminescence emission intensity at around 600 nm wavelength as a result of quantum confinement effects from the presence of sp{sup 2} C clusters embedded in the a-SiC and a-C phases in the films. - Highlights: ► Effects of radio frequency (r.f.) power on silicon carbon (SiC) films were studied. ► Hybrid plasma enhanced chemical vapor deposition/sputtering technique was used. ► r.f. power influences C incorporation in the film structure. ► High C incorporation results in higher ordering of the amorphous C phase. ► These films produced high photoluminescence emission intensity.

  7. Effect of anionic dopants on thickness, morphology and electrical properties of polypyrrole ultra-thin films prepared by in situ chemical polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Mahmoodian, Mehrnoosh [Dep. of Polymer Engineering, Nanostructured Materials Research Center, Sahand University of Technology, Tabriz 51335-1996 (Iran, Islamic Republic of); Pourabbas, Behzad, E-mail: pourabas@sut.ac.ir [Dep. of Polymer Engineering, Nanostructured Materials Research Center, Sahand University of Technology, Tabriz 51335-1996 (Iran, Islamic Republic of); Mohajerzadeh, Shams [Nano-Electronics and Thin Film Lab, School of Electrical and Computer Engineering, University of Tehran, P.O. Box 14395/515, Tehran (Iran, Islamic Republic of)

    2015-05-29

    The effect of different dopant anions on deposition and characteristics of polypyrrole (PPy) thin film has been studied in this work. Ultra-thin films of conducting PPy were deposited on insulating surfaces of glass and oxidized silicon wafer by in situ chemical polymerization in the presence of different anionic dopants including sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, α-naphthalene sulfonic acid, anthraquinone-2-sulfonic acid sodium salt monohydrate/5-sulfosalicylic acid dehydrate, and camphor sulfonic acid. Hydrophilic/hydrophobic properties and morphology of the self-assembled monolayer of N-(3-trimethoxysilylpropyl)pyrrole, the surface modifying agent in this work, and PPy thin films were characterized before and after deposition by contact angle measurements, field emission scanning electron microscopy, and atomic force microscopy. Chemical structure, thickness, and conductivity of the thin films were also studied by attenuated total reflectance Fourier transform infrared spectrometer, ellipsometry, and four-point probe measurements. The results showed deposition of thin films of conducting PPy with comparable thickness in the range of 6-31 nm and different morphologies, uniformity, and smoothness with average roughness in the range of 0.3-6 nm and relatively high range of conductivity on the modified surfaces. - Highlights: • Conducting thin films of polypyrrole were deposited on glass and SiO{sub 2} substrates. • Surface modification using pyrrole-silane was employed prior to polymerization. • Films as thin as ≈ 7 nm were deposited using different surfactant/counter ions. • Chemistry of the counter ion affects thickness, conductivity and morphology. • Lower thickness/higher conductivity were obtained by structurally flexible dopants.

  8. Studies on structural and thermo-chemical behavior of MFe12O19(s) (M = Sr, Ba and Pb) prepared by citrate-nitrate gel combustion method

    International Nuclear Information System (INIS)

    The citrate-nitrate gel combustion route was used to prepare SrFe12O19(s), BaFe12O19(s) and PbFe12O19(s). The compounds were characterized by Rietveld profile analysis of the X-ray powder diffraction data. The thermal expansion coefficients of MFe12O19 (M = Sr, Ba and Pb) were determined using high temperature powder X-ray diffraction data. The lattice parameters of these compounds were fitted into polynomial expressions as a function of temperature. Melting points of MFe12O19 (M = Sr, Ba and Pb) were determined using high temperature calorimeter and the values are; 1632 K, 1611 K and 1538 K, respectively. Standard molar heat capacities of BaFe12O19(s) and PbFe12O19(s) were determined from 130 K to 850 K using a heat flux type differential scanning calorimeter (DSC) and heat capacity anomalies were observed at 725 K and 718 K, respectively. This heat capacity anomaly is due to the magnetic order-disorder transition from ferrimagnetic state to paramagnetic state

  9. Preparation of YBa{sub 2}Cu{sub 3}O{sub 7-x} superconducting films: influence of the chemical composition on the sintering

    Energy Technology Data Exchange (ETDEWEB)

    Benavidez, E.; Quaranta, N.; Gonzalez Oliver, C.J.R.; Caruso, R. [FRSN, UTN, San Nicolas (Argentina). Desarrollo y Tecnologia de Materiales; de Sanctis, O. [Laboratorio de Materiales Ceramicos, FCEIyA, UNR-IFIR, Av. Pellegrini 250 (2000), Rosario (Argentina); Frattini, A. [Area Fisica-Dpto de Quimica Fisica-FCByF-UNR, Suipacha 531(2000), Rosario (Argentina)

    1999-12-01

    The influence of the cationic ratio Y:Ba:Cu on the kinetics of densification of the YBa{sub 2}Cu{sub 3}O{sub 7-x} (YBCO) superconductor ceramic was studied. The powders were prepared from organic precursors and the nominal compositions were: (A) stoichiometric composition YBa{sub 2}Cu{sub 3}O{sub 7-x}, (B) composition on the tie line joining YBa{sub 2}Cu{sub 3}O{sub 7-x}-BaCuO{sub 2} phases, and (C) composition in the triangle YBa{sub 2}Cu{sub 3}O{sub 7-x}-Y{sub 2}BaCuO{sub 5}-CuO. The phases present in these powders heated to 890 C were detected by X-ray diffraction (XRD), while the ratio Y:Ba:Cu was measured by neutronic activation analysis (NAA). The reactions between 900 C and 1070 C under O{sub 2} atmosphere were determined by differential thermal analysis (DTA) at a heating rate of 10 C/min. Compacts of different powders were obtained by uniaxial pressing and were then studied by dilatometric experiments under similar conditions as established in DTA measurements. The dilatometric curves were applied to different sintering models to obtain the validity ranges and activation energies corresponding to the different densification mechanisms that operate in the initial and intermediate stages of sintering. (orig.)

  10. Synthesis, structure and magnetic properties of Y3Fe5-xAlxO12 garnets prepared by the soft chemical method

    Directory of Open Access Journals (Sweden)

    Pedro Paulo Silva Ortega

    2014-12-01

    Full Text Available A study was undertaken about the structural, morphological and magnetic properties at room temperature of crystalline aluminium substituted yttrium iron garnet, YIG (Y3Fe5-xAlxO12 with 1.5< x <1.7 nanoparticles prepared by polymeric precursor method at the temperature of 700 °C for 2 hours. The single-phase character and the well-defined structure of YIG nanoparticles were confirmed by X-ray diffraction, excluding the presence of any other phases. The Raman spectra showed that the changes of lattice vibration would influence interaction between the Fe ion and the host. Mean crystallite size of the single-phase powder was about 46–65 nm. Particles’ morphology was investigated by high-resolution transmission electron microscopy, which shows that the particles were agglomerated. From hysteresis loops, particles’ efficiency range from 91.4% to 95.9% as Fe/Al ratio decreases. Saturation magnetization was affected by the particle size and Fe/Al stoichiometric ratio. We observe that the saturation magnetization increases as the Fe/Al ratio is raised due to enhancement of the surface spin effects.

  11. Chemical and microstructural study in radio frequency sputtered CdTe oxide films prepared at different N{sub 2}O pressures. Oxygen incorporation and film resputtering

    Energy Technology Data Exchange (ETDEWEB)

    Caballero-Briones, F. [CICATA-IPN Unidad Altamira, Km 14.5 Carretera Tampico-Puerto Industrial Altamira, 89600, Altamira, Tamps (Mexico)], E-mail: fcaballerobriones@ub.edu; Oliva, A.I.; Bartolo-Perez, P. [Applied Physics Department, CINVESTAV-IPN Unidad Merida, A.P. 73 Cordemex, 97310 Merida, Yucatan (Mexico); Zapata-Navarro, A. [CICATA-IPN Unidad Legaria, Legaria 694 Col. Irrigacion 11500, Mexico, D.F. (Mexico); Pena, J.L. [Applied Physics Department, CINVESTAV-IPN Unidad Merida, A.P. 73 Cordemex, 97310 Merida, Yucatan (Mexico)

    2008-10-01

    CdTe oxide films were grown by radio frequency sputtering in Ar-N{sub 2}O plasma at different N{sub 2}O partial pressures. The film oxygen content determined by Auger electron spectroscopy ranged from 15 to 60 at.%. The free O{sub 2} production during film deposition was monitored by in situ mass spectroscopy and it was found that it increases linearly over a critical N{sub 2}O pressure {approx} 4.7 x 10{sup -3} Pa alike the oxygen in the films. Film microstructure was studied by Raman spectroscopy and atomic force microscopy. Evidence of bands related to terminal Te-O vibrations was found in films prepared below the N{sub 2}O critical pressure, becoming predominant in films with higher oxygen content. The morphology and roughness evolution of the films confirm that they consist of a mixture of phases. Surface structures of the Ia-type and of the Ib-type were observed below and above the critical N{sub 2}O pressure. Eventually, ion bombardment process caused film resputtering.

  12. Chemical and microstructural study in radio frequency sputtered CdTe oxide films prepared at different N2O pressures. Oxygen incorporation and film resputtering

    International Nuclear Information System (INIS)

    CdTe oxide films were grown by radio frequency sputtering in Ar-N2O plasma at different N2O partial pressures. The film oxygen content determined by Auger electron spectroscopy ranged from 15 to 60 at.%. The free O2 production during film deposition was monitored by in situ mass spectroscopy and it was found that it increases linearly over a critical N2O pressure ∼ 4.7 x 10-3 Pa alike the oxygen in the films. Film microstructure was studied by Raman spectroscopy and atomic force microscopy. Evidence of bands related to terminal Te-O vibrations was found in films prepared below the N2O critical pressure, becoming predominant in films with higher oxygen content. The morphology and roughness evolution of the films confirm that they consist of a mixture of phases. Surface structures of the Ia-type and of the Ib-type were observed below and above the critical N2O pressure. Eventually, ion bombardment process caused film resputtering

  13. Wet chemical preparation of YVO4:Eu thin films as red-emitting phosphor layers for fully transparent flat dielectric discharge lamp

    International Nuclear Information System (INIS)

    Highly transparent YVO4:Eu thin films were deposited via dip coating of liquid nanoparticle dispersions on glass substrates. Annealing of the nanoparticle layers resulted in restructuring of the material into oriented crystalline films. The crystallinity was confirmed using powder X-ray diffraction. Film thickness was adjusted to 467 nm by multiple deposition. The resulting coatings show > 99% absorbance for wavelength below 300 nm and > 90% transmission in the visible spectral range. Under UV-light excitation a bright red photoluminescence with a quantum efficiency of 20% is observed. A planar, transparent dielectric barrier discharge lamp was constructed using YVO4:Eu coated glasses and transparent electrodes made from antimony-doped tin dioxide thin films. - Highlights: ► Preparation of highly transparent Eu3+ doped YVO4 phosphor thin films. ► Improved crystallinity and optical properties through heat treatment. ► Red emitting films on glass substrates were combined with antimony tin oxide thin films. ► Fully transparent, planar gas discharge lamp as prototype for a light emitting window.

  14. Preparation of Cauliflower-like ZnO Films by Chemical Bath Deposition:Photovoltaic Performance and Equivalent Circuit of Dye-sensitized Solar Cells

    Institute of Scientific and Technical Information of China (English)

    Yuqiao Wang; Xia Cui; Yuan Zhang; Xiaorui Gao; Yueming Sun

    2013-01-01

    The uniform cauliflower-like ZnO films were deposited on the conducting substrate by a chemical bath deposition in urea/water solution.The film structure and morphology were characterized by X-ray diffraction,thermogravimetric differential thermal analysis,energy dispersive spectroscopy,selected area electron diffraction,field emission scanning electron microscopy and high resolution transmission electron microscopy.The average diameter of ZnO nanoparticles and the petal thickness were 25 nm and 8 μm,respectively.Dyesensitized solar cells based on the cauliflower-like ZnO film electrode showed the short-circuit current density of 6.08 mA/cm2,the open-circuit photovoltage of 0.66 V,the fill factor of 0.55 and the overall conversion efficiency of 2.18%.The equivalent circuit of cells based on the ZnO film electrodes was measured by the electrochemical impedance spectroscopy.Furthermore,the analysis of equivalent circuit provided the relationship between the cell performance and the interfacial resistance,such as the shunt resistance and the series resistance.

  15. Optical and structural properties of microcrystalline GaN on an amorphous substrate prepared by a combination of molecular beam epitaxy and metal–organic chemical vapor deposition

    Science.gov (United States)

    Min, Jung-Wook; Hwang, Hyeong-Yong; Kang, Eun-Kyu; Park, Kwangwook; Kim, Ci-Hyun; Lee, Dong-Seon; Jho, Young-Dahl; Bae, Si-Young; Lee, Yong-Tak

    2016-05-01

    Microscale platelet-shaped GaN grains were grown on amorphous substrates by a combined epitaxial growth method of molecular beam epitaxy (MBE) and metal–organic chemical vapor deposition (MOCVD). First, MBE GaN was grown on an amorphous substrate as a pre-orienting layer and its structural properties were investigated. Second, MOCVD grown GaN samples using the different growth techniques of planar and selective area growth (SAG) were comparatively investigated by transmission electron microscopy (TEM), cathodoluminescence (CL), and photoluminescence (PL). In MOCVD planar GaN, strong bound exciton peaks dominated despite the high density of the threading dislocations (TDs). In MOCVD SAG GaN, on the other hand, TDs were clearly reduced with bending, but basal stacking fault (BSF) PL peaks were observed at 3.42 eV. The combined epitaxial method not only provides a deep understanding of the growth behavior but also suggests an alternative approach for the growth of GaN on amorphous substances.

  16. Modified DLC coatings prepared in a large-scale reactor by dual microwave/pulsed-DC plasma-activated chemical vapour deposition

    International Nuclear Information System (INIS)

    Diamond-Like Carbon (DLC) films find abundant applications as hard and protective coatings due to their excellent mechanical and tribological performances. The addition of new elements to the amorphous DLC matrix tunes the properties of this material, leading to an extension of its scope of applications. In order to scale up their production to a large plasma reactor, DLC films modified by silicon and oxygen additions have been grown in an industrial plant of 1m3 by means of pulsed-DC plasma-activated chemical vapour deposition (PACVD). The use of an additional microwave (MW) source has intensified the glow discharge, partly by electron cyclotron resonance (ECR), accelerating therefore the deposition process. Hence, acetylene, tetramethylsilane (TMS) and hexamethyldisiloxane (HMDSO) constituted the respective gas precursors for the deposition of a-C:H (DLC), a-C:H:Si and a-C:H:Si:O films by dual MW/pulsed-DC PACVD. This work presents systematic studies of the deposition rate, hardness, adhesion, abrasive wear and water contact angle aimed to optimize the technological parameters of deposition: gas pressure, relative gas flow of the monomers and input power. This study has been completed with measures of the atomic composition of the samples. Deposition rates around 1 μm/h, typical for standard processes held in the large reactor, were increased about by a factor 10 when the ionization source has been operated in ECR mode

  17. Effect of rapid thermal annealing on the structural and electrical properties of solid ZnO/NiO heterojunctions prepared by a chemical solution process

    International Nuclear Information System (INIS)

    Transparent pn-heterojunction electrodes composed of n-type zinc oxide (ZnO) nanorod arrays and p-type NiO are fabricated by a chemical solution route combined with rapid thermal annealing (RTA). The effects of RTA treatment (450 °C, 1 min) in reducing atmosphere on the structural properties and alignment of the ZnO nanorods are investigated. SEM images and XRD patterns show that the average diameter and length are increased, and the alignment and crystal quality of the nanorod arrays are significantly improved. The RTA-treated ZnO shows uniform and well-aligned nanorod arrays with a high aspect ratio of ∼12.4. The structural improvements associated with ZnO crystalline and defect reduction are further verified from the enhanced UV to visible emission ratio by a photoluminescence analysis. Moreover, the effect of RTA on the I-V characteristics of the ZnO/NiO heterojunction electrodes is also investigated; the electrical parameters of the junction are determined from the forward-bias I-V characteristics using Cheung's method. The results reveal that the series resistance is significantly reduced from 784.4 to 114.8 Ω, which leads to better rectifying behaviour with rectifying slope increased to ∼6.67 mA V-1. The RTA-processed ZnO/NiO heterojunctions with excellent optoelectronic properties may find wide applications in sensors and solid-state oxide junction-based devices. (paper)

  18. Influence of Fe-doped on structural, electronic structural and optical properties of hydrogenated amorphous carbon films prepared by plasma enhanced chemical vapor deposition

    International Nuclear Information System (INIS)

    Fe-doped hydrogenated amorphous carbon (a-C:H:Fe) films were deposited from an isobutene/ferrocene/H2 gas mixture by plasma enhanced chemical metal organic vapor deposition. Raman spectra were used to characterize the bonding structure of the a-C:H:Fe films and hydrogenated amorphous carbon (a-C:H) films. Optical properties were investigated by the UV-vis spectroscopy and the photoluminescence spectra. The number of six-numbered rings of the a-C:H films increases and sp2 clustering of the films decreases after Fe-doping. The Tauc optical gap of the a-C:H:Fe films becomes narrower by 0.15-0.23 eV relative to the value of the a-C:H films. The narrowing of the optical gap after doping is attributed primarily to the extended state around the Fe deep level in the band gap and the narrowing of the π and π* band edge states because of the increase of the number of six-numbered rings in the a-C:H films. Fe deep level defects of the a-C:H:Fe films contribute chiefly to non-radiative recombination.

  19. Effect of the hydrogen flow rate on the structural and optical properties of hydrogenated amorphous silicon thin films prepared by plasma enhanced chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Ben Amor, Sana; Dimassi, Wissem; Ali Tebai, Mohamed; Ezzaouia, Hatem [Photovoltaic Laboratory Research and Technology Centre of Energy, Borj-Cedria Science and Technology Park, BP 95, 2050 Hammam-Lif (Tunisia)

    2012-10-15

    Hydrogenated amorphous silicon (a-Si:H) thin films were deposited from pure silane (SiH{sub 4}) and hydrogen (H{sub 2}) gas mixture by plasma enhanced chemical vapor deposition (PECVD) method at low temperature (400 C) using high rf power (60 W). The structural and optical properties of these films are systematically investigated as a function of the flow rate of hydrogen (F{sub H2}).The surface morphology is analyzed by atomic force microscopy (AFM). The characterization of these films with low angle X-ray diffraction revealed that the crystallite size in the films tends to decrease with increase in (F{sub H2}). The Fourier transform infrared (FTIR) spectroscopic analysis showed that at low values of (F{sub H2}),the hydrogen bonding in Si:H films shifts from di-hydrogen (Si-H{sub 2}) and (Si-H{sub 2})n complexes to the mono-hydrogen (Si-H) bonding configuration. Finally, for these optimized conditions, the deposition rate decreases with increasing (F{sub H2}). (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  20. Novel biosorbent with high adsorption capacity prepared by chemical modification of white pine (Pinus durangensis) sawdust. Adsorption of Pb(II) from aqueous solutions.

    Science.gov (United States)

    Salazar-Rabago, J J; Leyva-Ramos, R

    2016-03-15

    The natural sawdust (NS) from white pine (Pinus durangensis) was chemically modified by a hydrothermal procedure using citric, malonic and tartaric acids. The adsorption capacity of modified sawdust (MS) towards Pb(II) was considerably enhanced due to the introduction of carboxylic groups on the surface of MS during the modification, and the adsorption capacity was almost linearly dependent on the concentration of carboxylic sites. The NS surface was acidic, and the MS surface became more acidic after the modification. At T = 25 °C and pH = 5, the maximum adsorption capacity of the optimal MS towards Pb(II) was 304 mg/g, which is exceptionally high compared to NS and other MS reported previously. The adsorption capacity of MS was considerably reduced from 304 to 154 mg/g by decreasing the solution pH from 5 to 3 due to electrostatic interactions. The adsorption of Pb(II) on MS was reversible at pH = 2, but not at pH = 5. The contribution percentage of ion exchange to the overall adsorption capacity ranged from 70 to 99% and 10-66% at the initial pH of 3 and 5, respectively. Hence, the adsorption of Pb(II) on MS was mainly due to ion exchange at pH = 3 and to both ion exchange and electrostatic attraction at pH = 5.

  1. Effect of reaction time on structural, morphology and optical properties of ZnO nanoflakes prepared by chemical bath deposition method

    International Nuclear Information System (INIS)

    ZnO nanoflakes have been successfully synthesized by the chemical bath deposition (CBD) method for different reaction times. X-ray diffraction (XRD) results confirm the initial formation of the cubic ZnO structure. However, increasing the reaction time resulted into the emergence of the well-known hexagonal wurtzite structure of ZnO. Scanning electron microscopy images showed the presence of agglomerated nanoflakes. The morphology was found not to depend on synthesis time. UV–vis spectra showed a partially increase in the percentage reflectance and the absorption edges red shifted to the higher wavelength with an increase in synthesis time. The highest band gap energy was obtained for ZnO synthesized for 1 min, with its estimated band gap energy of 3.91±0.08 eV. The estimated band gap decreased with an increase in the reaction time. The photoluminescent intensity of the emission peak at 473 nm decreased with an increase in reaction time.

  2. Structure, mechanical, and frictional properties of hydrogenated fullerene-like amorphous carbon film prepared by direct current plasma enhanced chemical vapor deposition

    Science.gov (United States)

    Wang, Yongfu; Gao, Kaixiong; Zhang, Junyan

    2016-07-01

    In this study, fullerene like carbon (FL-C) is introduced in hydrogenated amorphous carbon (a-C:H) film by employing a direct current plasma enhanced chemical vapor deposition. The film has a low friction and wear, such as 0.011 and 2.3 × 10-9mm3/N m in the N2, and 0.014 and 8.4 × 10-8mm3/N m in the humid air, and high hardness and elasticity (25.8 GPa and 83.1%), to make further engineering applications in practice. It has several nanometers ordered domains consisting of less frequently cross-linked graphitic sheet stacks. We provide new evidences for understanding the reported Raman fit model involving four vibrational frequencies from five, six, and seven C-atom rings of FL-C structures, and discuss the structure evolution before or after friction according to the change in the 1200 cm-1 Raman band intensity caused by five- and seven-carbon rings. Friction inevitably facilitates the transformation of carbon into FL-C nanostructures, namely, the ultra low friction comes from both such structures within the carbon film and the sliding induced at friction interface.

  3. Porous Silicon & Titanium Dioxide Coatings Prepared by Atmospheric Pressure Plasma Jet Chemical Vapour Deposition Technique-A Novel Coating Technology for Photovoltaic Modules

    Directory of Open Access Journals (Sweden)

    S. Bhatt

    2011-01-01

    Full Text Available Atmospheric Pressure Plasma Jet (APPJ is an alternative for wet processes used to make anti reflection coatings and smooth substrate surface for the PV module. It is also an attractive technique because of it’s high growth rate, low power consumption, lower cost and absence of high cost vacuum systems. This work deals with the deposition of silicon oxide from hexamethyldisiloxane (HMDSO thin films and titanium dioxide from tetraisopropyl ortho titanate using an atmospheric pressure plasma jet (APPJ system in open air conditions. A sinusoidal high voltage with a frequency between 19-23 kHz at power up to 1000 W was applied between two tubular electrodes separated by a dielectric material. The jet, characterized by Tg ~ 600-800 K, was mostly laminar (Re ~ 1200 at the nozzle exit and became partially turbulent along the jet axis (Re ~ 3300. The spatially resolved emission spectra showed OH, N2, N2+ and CN molecular bands and O, H, N, Cu and Cr lines as well as the NO2 chemiluminescence continuum (450-800 nm. Thin films with good uniformity on the substrate were obtained at high deposition rate, between 800 -1000 nm.s-1, and AFM results revealed that coatings are relatively smooth (Ra ~ 2 nm. The FTIR and SEM analyses were better used to monitor the chemical composition and the morphology of the films in function of the different experimental conditions.

  4. Photooxidation of different organic dyes (RB, MO, TB, and BG) using Fe(III)-doped TiO 2 nanophotocatalyst prepared by novel chemical method

    Science.gov (United States)

    Ghorai, Tanmay K.; Biswas, Soumya K.; Pramanik, Panchanan

    2008-09-01

    The nano-structured Fe(III)-doped TiO 2 photocatalysts with anatase phase have been developed for the oxidation of non-biodegradable different organic dyes like methyl orange (MO), rhodamine B (RB), thymol blue (TB) and bromocresol green (BG) using UV-Hg-lamp. The different compositions of Fe xTi 1- xO 2 ( x = 0.005, 0.01, 0.05, and 0.1) nanocatalysts synthesized by chemical method (CM), have been characterized by X-ray diffraction (XRD), UV-vis diffuse reflectance spectra, specific surface area (BET), transmission electronic microscopy (TEM) analysis, XPS, ESR and zeta potential. From XRD analysis, the results indicate that all the compositions of Fe(III) doped in TiO 2 catalysts gives only anatase phase not rutile phase. For complete degradation of all the solutions of the dyes (MO, RB, TB, and BG), the composition with x = 0.005 is more photoactive compared all other compositions of Fe xTi 1- xO 2, and degussa P25. The decolorization rate of different dyes decreases as Fe(III) concentration in TiO 2 increases. The energy band gap of Fe(III)-doped TiO 2 is found to be 2.38 eV. The oxidation state of iron has been found to be 3+ from XPS and ESR show that Fe 3+ is in low spin state.

  5. Optical and Structural Properties of Microcrystalline GaN on an Amorphous Substrate Prepared by a Combination of Molecular Beam Epitaxy and Metal-Organic Chemical Vapor Deposition

    Energy Technology Data Exchange (ETDEWEB)

    Min, Jung-Wook; Hwang, Hyeong-Yong; Kang, Eun-Kyu; Park, Kwangwook; Kim, Ci-Hyun; Lee, Dong-Seon; Jho, Young-Dahl; Bae, Si-Young; Lee, Yong-Tak

    2016-05-01

    Microscale platelet-shaped GaN grains were grown on amorphous substrates by a combined epitaxial growth method of molecular beam epitaxy (MBE) and metal-organic chemical vapor deposition (MOCVD). First, MBE GaN was grown on an amorphous substrate as a pre-orienting layer and its structural properties were investigated. Second, MOCVD grown GaN samples using the different growth techniques of planar and selective area growth (SAG) were comparatively investigated by transmission electron microscopy (TEM), cathodoluminescence (CL), and photoluminescence (PL). In MOCVD planar GaN, strong bound exciton peaks dominated despite the high density of the threading dislocations (TDs). In MOCVD SAG GaN, on the other hand, TDs were clearly reduced with bending, but basal stacking fault (BSF) PL peaks were observed at 3.42 eV. The combined epitaxial method not only provides a deep understanding of the growth behavior but also suggests an alternative approach for the growth of GaN on amorphous substances.

  6. Effect of copper doping on structural, optical and electrical properties of Cd0.8Zn0.2S films prepared by chemical bath deposition

    Indian Academy of Sciences (India)

    K Hadasa; G Yellaiah; M Nagabhushanam

    2014-02-01

    Cd0.8Zn0.2S:Cu films of 1.3–6.1 mole percentage of copper have been grown on mica substrate by using chemical bath deposition technique. The films have been characterized by using XRD, SEM and UV spectrophotometer. X-ray diffraction studies have shown that the films are polycrystalline. The average crystallite size as measured from XRD data is in the range of 125–130 nm. The activation energies of Cd0.8Zn0.2S:Cu films, as observed from d.c. conductivity studies in the temperature range (77–300 K) studied, decreased with the increase in Cu concentration. The optical absorption studies have revealed that the energy gap increases gradually with an increase in Cu concentration, whereas conductivity studies have shown an anomalous increase in conductivity in films of 3.8 mole percentage of Cu. SEM pictures have revealed the presence of defects with spherical structure having fibre network. The variation of electrical conductivity is explained based on the defects present and by adopting tunneling mechanism.

  7. Strong interfacial magnetic coupling in epitaxial bilayers of LaCoO{sub 3}/LaMnO{sub 3} prepared by chemical solution deposition

    Energy Technology Data Exchange (ETDEWEB)

    Vila-Fungueiriño, José Manuel; Rivas-Murias, Beatriz, E-mail: beatriz.rivas@usc.es; Rivadulla, Francisco

    2014-02-28

    We report the synthesis of high quality epitaxial bilayers of LaMnO{sub 3}/LaCoO{sub 3} (LCO/LMO) on (001) LaAlO{sub 3}, by spin-coating of a polymeric aqueous solutions. The bilayer shows a very large increase of the magnetization coercive field (≈ 3000%) with respect to the isolated LMO or LCO films. We suggest that the origin of this effect is a strong Mn{sup 4+}–O–Co{sup 2+} exchange interaction at the interface. Our results demonstrate that a simple chemical method is able to produce high quality epitaxial heterostructures in which interfacial effects can modify substantially the properties of the individual layers. - Highlights: • Synthesis of high quality epitaxial bilayers of LaMnO{sub 3}/LaCoO{sub 3} on (001) LaAlO{sub 3} • Polymer assisted deposition method • Interfacial effects can modify substantially the properties of the individual layers.

  8. Structural, optical and electrical properties of Cu2FeSnX4 (X = S, Se) thin films prepared by chemical spray pyrolysis

    International Nuclear Information System (INIS)

    Highlights: • CFTS(Se) thin films have been synthesized by low-cost spray-based deposition. • The fabricated films were found to be of stannite structure and p-type conductivity. • Band gaps of CFTS and CFTSe thin films are 1.37 and 1.11 eV, respectively. - Abstract: We report on fabrication of polycrystalline Cu2FeSnX4 (X = S, Se) thin films by chemical spray pyrolysis subsequent with post-sulfurization and selenization. The post-annealing of as-sprayed Cu2FeSnS4 (CFTS) films in sulfur and selenium ambient demonstrated drastically improved surface texture as well as crystallinity. The crystal lattice parameters calculated from X-ray diffraction patterns for post-annealed films were found to be consistent with stannite structure. The fabricated Cu2FeSnS4 (CFTS) and Cu2FeSnSe4 (CFTSe) films showed p-type conductivity with carrier concentration in the range of 1021 cm−3 and mobility ∼1–5 cm2 V−1 s−1. The band gap energies of post-sulfurized CFTS and post-selenized CFTSe films were estimated to be ∼1.37 eV and ∼1.11 eV with an error of ±0.02 eV by UV–Vis absorption, respectively, which are promising for photovoltaic application

  9. Preparation, Physical and Chemical Properties of Enteromorpha Prolifera Polysaccharide Iron Complex%浒苔多糖铁的制备及其理化性质研究

    Institute of Scientific and Technical Information of China (English)

    姜峻; 余腾飞; 张忠山

    2012-01-01

    Enteromorpha prolifera polysaccharide iron complex was synthesized and its physical and chemical properties was studied. Enteromorpha prolifera polysaccharide was reacted with ferric chloride to obtain polysaccharide iron complex. The structure of polysaccharide iron complex was identified by infrared spectroscopy. Complete the qualitative identification of polysaccharide iron complex by comparing with ferric hydroxide sol; conduct the reduction experiment via phenanthroline colorimetric. The iron content of polysaccharide iron complex was 2.53%; polysaccharide iron remained stable in pH 6-10; at 37℃, Fe3+ in the complex was completely reduced to Fe2+ by ascorbic acid. The results showed Enteromorpha prolifera polysaccharide iron was expected to be a good iron agent.%人工合成浒苔多糖铁复合物并研究其理化性质。用浒苔多糖与氯化铁反应制得浒苔多糖铁复合物;利用红外光谱法确定浒苔多糖铁复合物的结构;通过体外溶出试验测定浒苔多糖铁复合物中的铁含量;通过水解试验,考察浒苔多糖铁在不同pH时的稳定情况。通过邻菲罗啉比色法,对浒苔多糖铁进行还原性试验。硒浒苔多糖铁中铁含量为2.53%;浒苔多糖铁在pH6~10性质稳定;37℃时,Fe3+被抗坏血酸完全还原为Fe2+。浒苔多糖铁将来有望发展成为优良的补铁剂。

  10. Structural, optical and electrical properties of Cu{sub 2}FeSnX{sub 4} (X = S, Se) thin films prepared by chemical spray pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Khadka, Dhruba B.; Kim, JunHo, E-mail: jhk@inu.ac.kr

    2015-07-25

    Highlights: • CFTS(Se) thin films have been synthesized by low-cost spray-based deposition. • The fabricated films were found to be of stannite structure and p-type conductivity. • Band gaps of CFTS and CFTSe thin films are 1.37 and 1.11 eV, respectively. - Abstract: We report on fabrication of polycrystalline Cu{sub 2}FeSnX{sub 4} (X = S, Se) thin films by chemical spray pyrolysis subsequent with post-sulfurization and selenization. The post-annealing of as-sprayed Cu{sub 2}FeSnS{sub 4} (CFTS) films in sulfur and selenium ambient demonstrated drastically improved surface texture as well as crystallinity. The crystal lattice parameters calculated from X-ray diffraction patterns for post-annealed films were found to be consistent with stannite structure. The fabricated Cu{sub 2}FeSnS{sub 4} (CFTS) and Cu{sub 2}FeSnSe{sub 4} (CFTSe) films showed p-type conductivity with carrier concentration in the range of 10{sup 21} cm{sup −3} and mobility ∼1–5 cm{sup 2} V{sup −1} s{sup −1}. The band gap energies of post-sulfurized CFTS and post-selenized CFTSe films were estimated to be ∼1.37 eV and ∼1.11 eV with an error of ±0.02 eV by UV–Vis absorption, respectively, which are promising for photovoltaic application.

  11. Preparation of 1-bromoheptacosane

    International Nuclear Information System (INIS)

    Alkybromides are ones of the main organic precursors for fatty acids and alcohols labelling with Carbon 1-14. In this work the preparation of 1-bromoheptacosane by bromodescarboxylation of 1-octacosanoic acid is described. The synthesis yielded 80.5% of final product and more than 97% of chemical purity. Clean-up procedure modifications and spectral data bromoheptacosane are also reported

  12. Studies on Preparation and Physico-chemical Properties of Coating-agent for Controlled Release Fertilizer%控释肥包衣剂的制备及理化性质研究

    Institute of Scientific and Technical Information of China (English)

    刘英; 熊海蓉; 祝友; 熊远福; 李霞; 刘俊

    2013-01-01

      为了获得控释肥包衣剂的制备条件、探明其理化性质,以2种树脂为成膜材料,探讨了成膜材料复合比、成膜材料用量、增塑剂用量、乳化剂用量等单因素对控释肥包衣剂制备效果的影响,运用正交试验L9(34)确定了控释肥包衣剂制备的最佳条件;并对其pH、粘度、成膜时间、成膜性、衣膜水溶性、包衣均匀度、包衣脱落率等理化性质进行了测定。结果表明,控释肥包衣剂的最佳制备条件:树脂JZ与BZ复合比1:1.5,成膜材料用量12%,增塑剂用量0.8%,乳化剂用量1.0%,色素用量0.08%,乙酸乙酯用量86.12%。理化性质测定结果显示:pH 5.21,粘度为21.1 MPa/s,成膜性良好,衣膜不溶于水,成膜时间为6 min,包衣均匀度95%,包衣脱落率<8%,表明所制备的控释肥包衣剂理化性质良好。%To obtain the preparation conditions and explore the physico-chemical properties of coating-agent for controlled release fertilizer, the single factor tests of the composite ratio of film-forming materials, the amount of film-forming materials, plasticizer, emulsifier and pigment were made with two resins as the film-forming materials, and the optimal preparation conditions of coating-agent for controlled-fertilizer were determined by orthogonal test L9(34). The physico-chemical properties of the pH, viscosity, film-forming time, film-forming properties, water solubility of coated film, coating uniformity, coating-off rate were measured. The results showed that, the optimal preparation conditions were as follows:the composite ratio (JZ:BZ) was 1:1.5, amount of film-forming materials was 12%, plasticizer was 0.8%, emulsifier was 1.0%, pigment was 0.08% and solvent was 86.12%. Test results of physico-chemical properties showed that, the pH was 5.21, viscosity was 21.1 MPa/s, the film was good and indissolvable in water, the film-forming time was 6 min, coating uniformity was 95%, coating

  13. 控释肥包衣剂的制备及理化性质研究%Studies on Preparation and Physico-chemical Properties of Coating-agent for Controlled Release Fertilizer

    Institute of Scientific and Technical Information of China (English)

    刘英; 熊海蓉; 祝友; 熊远福; 李霞; 刘俊

    2013-01-01

      为了获得控释肥包衣剂的制备条件、探明其理化性质,以2种树脂为成膜材料,探讨了成膜材料复合比、成膜材料用量、增塑剂用量、乳化剂用量等单因素对控释肥包衣剂制备效果的影响,运用正交试验L9(34)确定了控释肥包衣剂制备的最佳条件;并对其pH、粘度、成膜时间、成膜性、衣膜水溶性、包衣均匀度、包衣脱落率等理化性质进行了测定。结果表明,控释肥包衣剂的最佳制备条件:树脂JZ与BZ复合比1:1.5,成膜材料用量12%,增塑剂用量0.8%,乳化剂用量1.0%,色素用量0.08%,乙酸乙酯用量86.12%。理化性质测定结果显示:pH 5.21,粘度为21.1 MPa/s,成膜性良好,衣膜不溶于水,成膜时间为6 min,包衣均匀度95%,包衣脱落率<8%,表明所制备的控释肥包衣剂理化性质良好。%To obtain the preparation conditions and explore the physico-chemical properties of coating-agent for controlled release fertilizer, the single factor tests of the composite ratio of film-forming materials, the amount of film-forming materials, plasticizer, emulsifier and pigment were made with two resins as the film-forming materials, and the optimal preparation conditions of coating-agent for controlled-fertilizer were determined by orthogonal test L9(34). The physico-chemical properties of the pH, viscosity, film-forming time, film-forming properties, water solubility of coated film, coating uniformity, coating-off rate were measured. The results showed that, the optimal preparation conditions were as follows:the composite ratio (JZ:BZ) was 1:1.5, amount of film-forming materials was 12%, plasticizer was 0.8%, emulsifier was 1.0%, pigment was 0.08% and solvent was 86.12%. Test results of physico-chemical properties showed that, the pH was 5.21, viscosity was 21.1 MPa/s, the film was good and indissolvable in water, the film-forming time was 6 min, coating uniformity was 95%, coating

  14. Sucos de laranja industrializados e preparados sólidos para refrescos: estabilidade química e físico-química Industrialized orange juices and refreshment prepared from orange juice powder: chemical and physicochemical stability

    Directory of Open Access Journals (Sweden)

    Patricia T. Silva

    2005-09-01

    Full Text Available O suco de laranja in natura é considerado uma das melhores fontes de vitamina C da dieta. No entanto, o ritmo de vida acelerado da sociedade atual associado à praticidade de preparo e armazenamento tem levado ao aumento do consumo de sucos e refrescos industrializados, porém pouco se conhece sobre a estabilidade destes produtos. Com o objetivo de avaliar a estabilidade de sucos de laranja prontos para o consumo (SPC e de refrescos elaborados a partir de preparados sólidos (PSR, foram determinados os teores de ácido ascórbico (AA e de sólidos solúveis totais (SST, a acidez total titulável (ATT e o pH. O teor de AA dos SPC variou de 17,25mg% a 62,40mg% (p = 0,05. Duas amostras apresentaram teor de AA inferior ao mínimo estabelecido pela legislação. Para os refrescos elaborados a partir dos PSR, o teor de AA variou entre 0,67mg% e 32,00mg% (p = 0,05. O pH e o teor de SST mantiveram-se constantes, enquanto que a ATT apresentou variações durante o armazenamento. Os SPC podem ser considerados como fonte de vitamina C, ao contrário da maioria dos refrescos elaborados a partir dos PSR que não podem ser considerados fontes importantes desta vitamina.Fresh orange juice is considered to be one of the best sources of vitamin C. Nevertheless, hand squeezed juice is often inconvenient for consumers who seek practical and fast ways to prepare their meals. The objective of this study was to analyze the chemical and physicochemical stability of ready to drink and refreshments prepared from orange juice powder commercially available in the city of Rio de Janeiro. The ascorbic acid (AA content, total soluble solids (TSS, total tritatable acidity (TAA and pH were determined. The AA content of ready to drink orange juice ranged from 17.25mg% to 62.40mg (p = 0.05. In two batches the AA content was lower than that established by the Brazilian legislation. The AA content of refreshments prepared from orange juice powder ranged from 0.67mg% to 32.00mg

  15. Surface properties of palladium catalysts supported on ternary ZrO2-Al2O3-WOx oxides prepared by the sol-gel method: Study of the chemical state of the support

    Science.gov (United States)

    Barrera, A.; Montoya, J. A.; del Angel, P.; Navarrete, J.; Cano, M. E.; Tzompantzi, F.; López-Gaona, A.

    2012-08-01

    The surface properties of Pd and Pd-Pt catalysts supported on binary ZrO2-WOx and ternary ZrO2-Al2O3-WOx oxides prepared by the sol-gel method were studied. Special attention was paid to the study of the texture of the catalysts as well as the chemical state of tungstated zirconia and tungstated zirconia promoted with alumina in the palladium catalysts. The catalysts were tested in the isomerization of n-hexane and were characterized by N2 physisorption, XRD, TPR, Raman spectroscopy, XPS and FT-IR of adsorbed pyridine. The catalysts had bimodal pore size distributions with mesopores in the range 55-70 Å and macropores of 1000 Å in diameter. The catalysts had a surface WOx coverage (4.4-6.0 W nm-2) lower than that of the theoretical monolayer (7.0 W nm-2). A lower acidity of the ternary ZrO2-Al2O3-WOx oxide as compared to the binary ZrO2-WOx oxide was found. Higher activity in the isomerisation of n-hexane was obtained in the Pd-Pt catalysts supported on ternary ZrAlW oxides prepared by sol-gel that is correlated with the coexistence on the surface of W4+ (WO2) or W0 and W6+ (Al2(WO4)3) species, ZrO2 in the tetragonal phase and a high amount of ZrOx suboxides species in a low oxidation state (Zr3+ and Zr2+).

  16. In vitro biocompatibility and antimicrobial activity of wet chemically prepared Ca10-xAgx(PO4)6(OH)2 (0.0 ≤ x ≤ 0.5) hydroxyapatites

    International Nuclear Information System (INIS)

    Herein, we report the effect of silver ions on the physical, antimicrobial and cytocompatibility properties of wet chemically synthesized silver doped Ca10-xAgx(PO4)6(OH)2 (0.0 ≤ x ≤ 0.5) hydroxyapatites (HAp). Silver ions containing HAp exhibit the comparable density, hardness and enhanced antimicrobial properties, in comparison to parent HAp. The optical absorption measurements confirm the presence of silver ions in the doped compositions, which are responsible for as increased antimicrobial property of doped HAp materials for x > 0.3. The cytotoxicity behavior of the doped HAp was evaluated using mouse fibroblast (L929) cell line. The important result has been that doped HAp (x > 0.3) exhibit statistically (significant) lower cell viability in comparison to undoped HAp. However, no difference in cellular functionality on doped HAp surfaces, in terms of cell adhesion and proliferation could be qualitatively observed in reference to undoped HAp. In order to explain the observed antimicrobial and cell viability properties, the in vitro release of Ag+ ions has been quantified using Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) and solubility was measured by weight loss in acetate buffer solution. - Research highlights: → Wet chemically prepared Silver doped Hydroxyapatites (HAp) showing the Comparable density and hardness in comparison to parent HAp. → 2% Silver doped HAp shows less solubility in acetate buffer in comparison to Parent HAp. → Enhanced antimicrobial property in very low concentration of silver content in Hydroxyapatite. → Silver doped HAp (x>0.3) exhibits statistically (significant) lower cell viability in comparison to parent HAp.

  17. Preparation Method of Chemical Reference Amentoflavone from Selaginella Tamariscina (Beauv.) Spring%卷柏中穗花杉双黄酮化学对照品的制备方法

    Institute of Scientific and Technical Information of China (English)

    刘朋朋; 刘 勇; 刘永刚; 蔡 伟; 张宏桂

    2012-01-01

    Objective To investigate the preparation method and analysis technique of chemical reference amentoflavone from Selaginella tamariscina(Beauv. ) Spring. Methods The chemical reference amentoflavone was isolated and purified by solvent extract and nhro-matography, which structure was determined by UV, IR, MS,1H - NMR and 13C - NMR. The purity was analyzed by TLC, HPLC. Results The TLC showes the amentoflavone has no impurity spot. The HPLC indicates that it's purity reaches 98.5% above. Conclusion The mothod of isolation and purification for amentoflavone reported in this paper is simple and economical.%目的 研究从卷柏中分离穗花杉双黄酮化学对照品的制备方法与分析技术.方法 采用溶剂和色谱方法从卷柏中分离、纯化、制备穗花杉双黄酮对照品,以紫外、红外光谱、质谱、氢谱和碳谱鉴定结构,以薄层色谱法、高效液相色谱法进行纯度检查.结果 制得的穗花杉双黄酮经薄层色谱法检查无杂质斑点,经高效液相色谱法检测纯度达98.5%以上.结论 所建立的分离、纯化方法简便,成本低.

  18. Modern Chemical Technology, Volume 5.

    Science.gov (United States)

    Pecsok, Robert L., Ed.; Chapman, Kenneth, Ed.

    This volume contains chapters 26-31 for the American Chemical Society (ACS) "Modern Chemical Technology" (ChemTeC) instructional material intended to prepare chemical technologists. Chapter 26 reviews oxidation and reduction, including applications in titrations with potassium permanganate and iodometry. Coordination compounds are described in the…

  19. Preparation and Chemical Compositions of Three Polysaccarides of Different Molecular Weights from Poria Cocos Wolf%三种不同分子量段茯苓多糖的制备以及其组成分析

    Institute of Scientific and Technical Information of China (English)

    黄灿; 赵骏

    2013-01-01

    Objective:Preparation and chemical compositions of three polysaccarides of different molecular weights and chemical compositions from Poria cocos Wolf were made.Methods:In this study,three polysaccharides were extracted from Poria cocos Wolf with water and sedimentation with alcohol of different concentrations.The polysacchardes were purified by sephadexG-75.Their chemical compositions were detected by TLC and GC-MS.Results:TLC and GC-MS revealed polysaccharide A was composed of mannose,glucose,galactose and fucose,and the mole ratio was 1.4 ∶ 1.17 ∶ 1∶4.21.Polysaccharide B was composed of mannose,glucose,galactose and fucose,and the mole ratio as 1 ∶ 2.36 ∶ 5.49 ∶ 2.34.Polysaccharide C was composed of mannose,glucose,galactose and fucose,and the mole ratio was 6∶81∶25 ∶ 1.Conclusion:The three polysaccharides were all composed of mannose,glucose,galactose and fucose with different mole ratios.%目的:对不同分子量段茯苓多糖进行提取、纯化以及单糖组成分析.方法:采用热水煮沸提取,三氯乙酸法除蛋白,不同浓度乙醇醇沉得到3种不同分子量段的茯苓多糖A、B、C,凝胶色谱柱纯化,样品水解经TLC及GC-MS分析确定单糖组成.结果:结果显示A由岩藻糖、甘露糖、葡萄糖、半乳糖组成,其摩尔比为:1.4∶1.17∶1∶4.21,B由岩藻糖、甘露糖、葡萄糖、半乳糖组成,其摩尔比为:1∶2.36∶5.49∶2.34,C由岩藻糖、甘露糖、葡萄糖、半乳糖组成,其摩尔比为:6∶81∶25∶1.结论:茯苓多糖A、B、C均由岩藻糖、甘露糖、葡萄糖和半乳糖以不同含量组成.

  20. Preparation of americium amalgam

    International Nuclear Information System (INIS)

    Using the method of NGR-spectroscopy with the aid of 241Am isotope chemical state of transuranium elements in the volume and on the surface of amalgams is studied. Amalgam preparation was realized in a simplified electrolytic cell. It is shown that in the process of amalgam preparation the first order of reaction as to actinide is observed; americium is distributed gradually over the volume and it is partially sorbed by the surface of glass capillary. NGR spectrum of dry residue after mercury distillation at 200 deg C points to the presence of americium-mercury intermetal compounds

  1. Chemical-physical properties of spinel CoMn2O4 nano-powders and catalytic activity in the 2-propanol and toluene combustion: Effect of the preparation method.

    Science.gov (United States)

    Hosseini, Seyed Ali; Salari, Dariush; Niaei, Aligholi; Deganello, Francesca; Pantaleo, Giuseppe; Hojati, Pejman

    2011-01-01

    Spinel-type CoMn(2)O(4)nano-powders are prepared using sol-gel auto combustion (SGC) and co-precipitation (CP) methods and their catalytic activities are evaluated in combustion of 2-propanol and toluene. The chemical-physical properties of the oxides are characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), N(2)-adsorption-desorption, temperature programmed reduction (TPR) and scanning electron microscopy (SEM). After calcination at 700°C, CoMn(2)O(4)-SGC shows higher amounts of the normal-type spinel phase and is more crystalline than CoMn(2)O(4)-CP. Higher calcination temperatures (850°C) do not affect very much the weight percentage of the normal-type spinel phase; although the crystal size slightly increased. The TPR analysis evidences a large number of Mn(3+) cations in CoMn(2)O(4)-SGC compared to CoMn(2)O(4)-CP. This difference, together with the higher surface area, could justify the higher activity of CoMn(2)O(4)-SGC in both the investigated reactions.

  2. An X-band Co2+ EPR study of Zn1-xCoxO (x=0.005-0.1) nanoparticles prepared by chemical hydrolysis methods using diethylene glycol and denaturated alcohol at 5 K

    Science.gov (United States)

    Misra, Sushil K.; Andronenko, S. I.; Srinivasa Rao, S.; Chess, Jordan; Punnoose, A.

    2015-11-01

    EPR investigations on two types of dilute magnetic semiconductor (DMS) ZnO nanoparticles doped with 0.5-10% Co2+ ions, prepared by two chemical hydrolysis methods, using: (i) diethylene glycol ((CH2CH2OH)2O) (NC-rod-like samples), and (ii) denatured ethanol (CH3CH2OH) solutions (QC-spherical samples), were carried out at X-band (9.5 GHz) at 5 K. The analysis of EPR data for NC samples revealed the presence of several types of EPR lines: (i) two types, intense and weak, of high-spin Co2+ ions in the samples with Co concentration >0.5%; (ii) surface oxygen vacancies, and (iii) a ferromagnetic resonance (FMR) line. QC samples exhibit an intense FMR line and an EPR line due to high-spin Co2+ ions. FMR line is more intense, than the corresponding line exhibited by NC samples. These EPR spectra varied for sample with different doping concentrations. The magnetic states of these samples as revealed by EPR spectra, as well as the origin of ferromagnetism DMS samples are discussed.

  3. Nanoscale Ferroelectric Switchable Polarization and Leakage Current Behavior in (Ba0.50Sr0.50(Ti0.80Sn0.20O3 Thin Films Prepared Using Chemical Solution Deposition

    Directory of Open Access Journals (Sweden)

    Venkata Sreenivas Puli

    2015-01-01

    Full Text Available Nanoscale switchable ferroelectric (Ba0.50Sr0.50(Ti0.80Sn0.20O3-BSTS polycrystalline thin films with a perovskite structure were prepared on Pt/TiOx/SiO2/Si substrate by chemical solution deposition. X-ray diffraction (XRD spectra indicate that a cubic perovskite crystalline structure and Raman spectra revealed that a tetragonal perovskite crystalline structure is present in the thin films. Sr2+ and Sn4+ cosubstituted film exhibited the lowest leakage current density. Piezoresponse Force Microscopy (PFM technique has been employed to acquire out-of-plane (OPP piezoresponse images and local piezoelectric hysteresis loop in polycrystalline BSTS films. PFM phase and amplitude images reveal nanoscale ferroelectric switching behavior at room temperature. Square patterns with dark and bright contrasts were written by local poling and reversible nature of the piezoresponse behavior was established. Local piezoelectric butterfly amplitude and phase hysteresis loops display ferroelectric nature at nanoscale level. The significance of this paper is to present ferroelectric/piezoelectric nature in present BSTS films at nanoscale level and corroborating ferroelectric behavior by utilizing Raman spectroscopy. Thus, further optimizing physical and electrical properties, BSTS films might be useful for practical applications which include nonvolatile ferroelectric memories, data-storage media, piezoelectric actuators, and electric energy storage capacitors.

  4. Preparation and Properties of N-Doped p-Type ZnO Films by Solid-Source Chemical Vapour Deposition with the c-Axis Parallel to the Substrate

    Institute of Scientific and Technical Information of China (English)

    吕建国; 叶志镇; 汪雷; 赵炳辉; 黄靖云

    2002-01-01

    We report on N-doped p-type ZnO films with the c-axis parallel to the substrate. ZnO films were prepared onan α-A12O3 (0001) substrate by solid-source chemical vapour deposition (CVD). Zn( CH3COO)2.2H2O was usedas the precursor and CH3COONH4 as the nitrogen source. The growth temperature was varied from 300℃ C to600℃ C. The as-grown ZnO film deposited at 500° C showed p-type conduction with its resistivity of 42 Ωcrm, carrierdensity 3.7 × 1017 cm-3 and Hall mobility 1.26cm2V-1.s-1 at room temperature, which are the best propertiesfor p-type ZnO deposited by CVD. The p-type ZnO film possesses a transmittance of about 85% in the visibleregion and a bandgap of 3.21 eV at room temperature.

  5. Examination of surface phenomena of V₂O₅ loaded on new nanostructured TiO₂ prepared by chemical vapor condensation for enhanced NH₃-based selective catalytic reduction (SCR) at low temperatures.

    Science.gov (United States)

    Cha, Woojoon; Yun, Seong-Taek; Jurng, Jongsoo

    2014-09-01

    In this article, we describe the investigation and surface characterization of a chemical vapor condensation (CVC)-TiO2 support material used in a V2O5/TiO2 catalyst for enhanced selective catalytic reduction (SCR) activity and confirm the mechanism of surface reactions. On the basis of previous studies and comparison with a commercial TiO2 catalyst, we examine four fundamental questions: first, the reason for increased surface V(4+) ion concentrations; second, the origin of the increase in surface acid sites; third, a basis for synergistic influences on improvements in SCR activity; and fourth, a reason for improved catalytic activity at low reaction temperatures. In this study, we have cited the result of SCR with NH3 activity for removing NOx and analyzed data using the reported result and data from previous studies on V2O5/CVC-TiO2 for the SCR catalyst. In order to determine the properties of suitable CVC-TiO2 surfaces for efficient SCR catalysis at low temperatures, CVC-TiO2 specimens were prepared and characterized using techniques such as XRD, BET, HR-TEM, XPS, FT-IR, NH3-TPD, photoluminescence (PL) spectroscopy, H2-TPR, and cyclic voltammetry. The results obtained for the CVC-TiO2 materials were also compared with those of commercial TiO2.

  6. Chemical Emergencies

    Science.gov (United States)

    When a hazardous chemical has been released, it may harm people's health. Chemical releases can be unintentional, as in the case of an ... the case of a terrorist attack with a chemical weapon. Some hazardous chemicals have been developed by ...

  7. Substrate preparation by contactless mechanochemical polish

    Science.gov (United States)

    Rotter, S.; Lachish, U.; El-Hanany, U.

    1985-10-01

    A simple, yet effective, polishing technique for substrate preparation is presented. It is contactless chemical polish which does not introduce any defects into the substrate during the process. The method can be readily adopted in all cases where chemical polishing is practical for substrate preparation. Results similar to those obtained by the more sophisticated hydroplaning method can be achieved.

  8. The Preparation of Graphene

    Institute of Scientific and Technical Information of China (English)

    Chen Yanyan

    2015-01-01

    Graphene has unique structure and possesses excellent physical and chemical properties, and it has received a great deal of attention in related research fields. The quality, quantity and application of graphene are related to its preparation methods. At present the bottleneck of graphene research is that both high-quality and large quantity of graphene could not be obtained simultaneously and the reason is that the basic mechanism of graphene formation has mot been wel understood.

  9. 碳酸钾化学活化法制备土霉素菌渣活性炭研究%Preparation of Oxytetracycline Bacterial Residue Activated Carbon by Chemical Activation with Potassium Carbonate

    Institute of Scientific and Technical Information of China (English)

    周保华; 高勤; 郭斌; 朱能

    2012-01-01

    为了解决制药行业土霉素菌渣处置的难题,该文以土霉素菌渣为原材料,K2CO3为活化剂,采用化学活化法制备土霉素菌渣活性炭.通过电镜扫描和氮气吸附对较佳条件下制备的活性炭特性进行了表征.实验得出制备土霉素菌渣活性炭的较佳工艺条件为:活化温度800℃,活化时间3h,活化比1∶3.该活性炭的苯酚吸附值为215 mg/g,比表面积达1 593.09 m2/g,亚甲基蓝吸附值为117 mg/g.该活性炭孔结构丰富,主要以微孔为主,平均孔径为1.09 nm,微孔孔容为0.54 cm3/g,中孔孔容为0.27 cm3/g.%In order to solve the problem of oxytetracycline bacterial residue disposal of pharmaceutical industry,the activated carbons prepared from oxytetracycline bacterial residue with K2CO3 under chemical activation are investigated here. The properties of the activated carbons under better conditions are performed by sanning electron microscopy and Nitrogen adsorption. Experimental results show that the better process conditions of preparation for oxytetracycline bacterial residue activated carbons are 800 ℃ activation temperature,3 h activation time and 1:3 activation ratio. The phenol adsorption of these activated carbons is 215 mg/g,the special surface area is 1 593. 09 m2/g and the methylene blue adsorption is 117 mg/g. The activated carbons are affluent in pores, which are mainly micropores. The average pore size of the activated carbons is 1. 09 nm, and the micropore volume and mesopore volume are 0. 54 cm3/g and 0. 27 cmVg respectively.

  10. KOH活化法高比表面积竹质活性炭的制备与表征%Preparation and characterization of high specific surface area activated carbon from bamboo by chemical activation with KOH

    Institute of Scientific and Technical Information of China (English)

    王秀芳; 张会平; 陈焕钦

    2006-01-01

    以竹屑为原料,研究了KOH活化法高比表面积活性炭的制备工艺.分别考察了浸渍比、活化温度、活化时间等工艺参数对产品吸附性能的影响,并提出了可能的活化机理.在所研究的实验条件下,最佳的制备工艺是浸渍比1.0,活化温度800℃,活化时间2h.所得到的活性炭产品的比表面积和孔容可达2996m2/g和1.64cm3/g.该产品附加值高,在吸附领域特别是在双电层电容器的电极材料领域有广阔的应用前景.%High specific surface area activated carbon was prepared from bamboo by chemical activation with KOH. The influence of activation parameters on the final products was investigated by varying the KOH/bamboo ratio, activation temperature and hold time. The samples were characterized by nitrogen adsorption isotherms at 77K. The specific surface area and pore volume of activated carbon were calculated by BET and t-plot method. The possible activation mechanism was also proposed. Under the experimental conditions, the optimum conditions for preparing high specific surface area activated carbon are at a KOH/precursor ratio of 1.0, an activation temperature of 800℃ and a hold time of 2h. With these experimental conditions, an activated carbon with a BET surface area of 2996m2/g and a total pore volume of 1.64cm3/g was produced. The product is a novel material for adsorption and for the application in electric double-layer capacitors.

  11. Mechanical and thermal properties of ceramsite foamed concrete prepared with chemical foaming method%化学发泡陶粒泡沫混凝土力学及热工性能研究

    Institute of Scientific and Technical Information of China (English)

    王康; 陈国新

    2016-01-01

    In order to improve crack resistance and thermal properties of foamed concrete, hydrogen peroxide, ceramsite, glazed hollow bead, glass fiber, and cement were used to prepare glass fiber-reinforced ceramsite foamed concrete blocks with the chemical foaming method. A single factor con-trol variate method was used to test the blocks, and the effect of various factors on mechanical and thermal properties of the concrete was analyzed. An optimal mixture ratio was obtained through a multiple linear regression analysis. The splitting tensile strength of the foamed blocks was between 0. 80 MPa and 0. 90 MPa, and the compressive strength was between 7. 0 MPa and 8. 0 MPa. Re-sults show that the brittleness of foamed concrete corresponds with the increase of the hydrogen per-oxide and glazed hollow bead contents. Glass fiber can improve the splitting tensile strength and thermal performance of foamed concrete. When the hydrogen peroxide, glass fiber and glazed hollow beads are 7. 5%, 1. 0%, 8. 5% and 8. 5% of the cement mass content, respectively, the thermal conductivity of foamed concrete is 0. 203 W/( m·k) , the splitting tensile strength is 0. 81 MPa, and the compressive strength is 7. 3 MPa. Glass fiber-reinforced ceramsite foamed concrete prepared with the chemical foaming method, have high ratio of tension to compression and good thermal properties.%为改善泡沫混凝土的抗裂性能和热工性能,利用双氧水、陶粒、玻化微珠、玻璃纤维、水泥等材料,通过化学发泡法制备玻璃纤维增强型陶粒泡沫混凝土砌块,并采用单因素控制变量法进行顺序试验,分析了各因素对材料力学性能和热工性能的影响,通过多元线性回归得出满足劈拉强度在0.80~0.90 MPa、抗压强度在7.0~8.0 MPa的泡沫混凝土砌块最优配合比。结果表明:泡沫混凝土脆性随双氧水、玻化微珠和陶粒用量的增加而显著增大;玻璃纤维既可提高泡沫混凝土强度,又可改善其热

  12. Chemical preparation, kinetics of thermal behavior and infrared studies of Pb3(P3O92.3H2O and Cd3(P3O92.14H2O

    Directory of Open Access Journals (Sweden)

    Said Belaaouad

    2013-05-01

    Full Text Available Chemical preparation, thermal behavior, kinetic and IR studies are given for the cyclotriphosphates Pb3(P3O92.3H2O and Cd3(P3O92.14H2O. The later cyclotriphosphates have never been studied except their crystallographic characterization and are stable in the conditions of temperature and pressure of our laboratory until 343K. The final products of the dehydration and calcination of Pb3(P3O92.3H2O and Cd3(P3O92.14H2O, under atmospheric pressure, are respectively their long chain polyphosphates, [Pb(PO32]∞ and β[Cd(PO32]∞. The intermediate product of the dehydration of Cd3(P3O92.14H2O, under atmospheric pressure, is its long chain polyphosphate form α, α[Cd(PO32]. [Pb(PO32]∞ and β[Cd(PO32]∞ are stable until their melting points at respectively 946K and 1153K. Two different methods, Ozawa and KAS have been selected in order to study the kinetics of thermal behavior of the cyclotriphosphates Pb3(P3O92.3H2O and Cd3(P3O92.14H2O for the first time. The kinetic and thermodynamic features of the dehydration, of the cited cyclotriphosphates, were determined and discussed on the basis of their crystalline structure. [Pb(PO32]∞, α[Cd(PO32] and β[Cd(PO32] have many applications in industry such as corrosion inhibitors.

  13. 机械活化固相化学反应制备木薯醋酸酯淀粉%Preparation for cassava starch acetate by mechanical activation-strengthened solid phase chemical reaction

    Institute of Scientific and Technical Information of China (English)

    陈渊; 杨家添; 黄祖强; 朱万仁; 唐春洁; 秦顾

    2013-01-01

    In order to develop a new preparation method of starch acetate,the cassava starch acetate was synthesized by mechanical activation-strengthened solid phase chemical reaction.The effects of acetic anhydride content,sodium hydroxide content,ball-milling temperature,ball-milling time,stirring speed and the volume of the stack for ball-milling media on esterification of cassava starch were investigated.The degree of substitution (DS) of starch acetate was used as the evaluating parameter.The best conditions of preparation technique were confirmed by orthogonal test.The optimum conditions of cassava starch acetate preparation were 60% acetic anhydride,2.0% sodium hydroxide,ball-milling temperature 60℃,ball-milling time 60min,stirring speed 380r/min,tack media 500 mL,the DS of the products 0.2632,and the RE was 25.57%.Furthermore,the structure of native starch and the starch acetate were further characterized by using Fourier transform infrared spectrometry (FTIR) and X-ray diffraction (XRD).The mechanical activation considerably enhanced the esterification of cassava starch.%为获得制备醋酸酯淀粉的新工艺,采用机械活化固相化学反应法制备木薯醋酸酯淀粉.以醋酸酯淀粉的取代度为评价指标,分别探讨醋酸酐用量、NaOH用量、球磨温度、球磨时间、搅拌速度、球磨介质的堆体积等因素对木薯淀粉醋酸酯反应的影响,并对影响因素进行了正交优化.结果表明:在醋酸酐质量分数60%、NaOH质量分数2.0%、球磨温度60℃、球磨时间60 min、搅拌速度380 r/min、球磨介质堆体积500 mL的反应条件下,制备得到的木薯醋酸酯淀粉的取代度为0.263 2,反应效率为25.57%.并采用红外光谱(FTIR)、X-射线衍射(XRD)对木薯醋酸酯淀粉的结构进行了表征.机械活化对淀粉发生酯反应有显著的强化作用.

  14. Chemical hygiene plan

    Energy Technology Data Exchange (ETDEWEB)

    1994-09-01

    This plan was written to administer and monitor safety measures and chemical hygiene principles in the TAC Uranium Mill Tailing Remedial Action Project sample preparation facility in Albuquerque, New Mexico. It applies to toxic and/or hazardous materials to radioactive materials.

  15. Chemical hygiene plan

    International Nuclear Information System (INIS)

    This plan was written to administer and monitor safety measures and chemical hygiene principles in the TAC Uranium Mill Tailing Remedial Action Project sample preparation facility in Albuquerque, New Mexico. It applies to toxic and/or hazardous materials to radioactive materials

  16. Partial chemical characterization of antigenic preparations of chromoblastomycosis agents Caracterização química parcial de preparações antigênicas de agentes da cromoblastomicose

    Directory of Open Access Journals (Sweden)

    Tania Fraga BARROS

    1999-11-01

    Full Text Available Antigenic preparations (saline, methylic, metabolic and exoantigens of four agents of chromoblastomycosis, Fonsecaea pedrosoi, Phialophora verrucosa, Cladophialophora (Cladosporium carrionii and Rhinocladiella aquaspersa were obtained. Partial chemical characterization of these antigenic preparations was obtained by determination of the levels of total lipids, protein, and carbohydrates, and identification of the main sterols and carbohydrates. Methylic antigens presented the highest lipid contents, whereas metabolic antigens showed the highest carbohydrate content. Total lipid, protein, and carbohydrate levels were in the range of 2.33 to 2.00mg/ml, 0.04 to 0.02 mg/ml and 0.10 to 0.02 mg/ml, respectively, in the methylic antigens and in the range of 0.53 to 0.18mg/ml, 0.44 to 0.26mg/ml, and 1.82 to 1.02 mg/ml, respectively, in saline antigens. Total lipid, protein, and carbohydrate contents were in the range of 0.55 to 0.20mg/ml, 0.69 to 0.57mg/ml and 10.73 to 5.93mg/ml, respectively, in the metabolic antigens, and in the range of 0.55 to 0.15mg/ml, 0.62 to 0.20mg/ml and 3.55 to 0.42mg/ml, respectively, in the exoantigens. Phospholipids were not detected in the preparations. Saline and metabolic antigens and exoantigens presented hexose and the methylic antigen revealed additional pentose units in their composition. The UV light absorption spectra of the sterols revealed squalene and an ergosterol fraction in the antigens. The characterization of these antigenic preparations may be useful for serological evaluation of patients of chromoblastomycosis.Preparações antigênicas (antígenos salinos, metílicos, metabólicos e exoantígenos de quatro agentes da cromoblastomicose, Fonsecaea pedrosoi, Phialophora verrucosa, Cladophialophora (Cladosporium carrionii e Rhinocladiella aquaspersa foram obtidos e foi determinada a caracterização química parcial dos mesmos. Os antígenos metílicos apresentaram os maiores teores de lípides enquanto os

  17. Difluoromethane preparation

    NARCIS (Netherlands)

    Wiersma, A.; Sandt, E.J.A.; Van Bekkum, H.; Makkee, M.; Moulijn, J.A.

    1996-01-01

    Abstract of NL 9401574 (A) The invention relates to a method for preparing difluoromethane, wherein dichlorodifluoromethane or monochlorodifluoromethane is brought into contact with hydrogen in the presence of palladium on activated carbon, wherein the loading of the palladium on the activated c

  18. 化学法制备低介电常数聚酰亚胺的研究进展%Progress in Preparation of Low Dielectric Constant Polyimide by Chemical Method

    Institute of Scientific and Technical Information of China (English)

    金成九; 王兴元; 王晓工; 和亚宁

    2012-01-01

    随着微电子工业的快速发展,为了提高大规模集成电路中芯片间的传输速度以满足高集成化的要求,需要层间绝缘材料具有较低的介电常数。聚酰亚胺已被广泛用于大规模集成电路的层间绝缘材料,降低其介电常数的研究在近年来受到了广泛关注。当采用化学方法降低介电常数时,调控聚酰亚胺的分子结构是基础;在聚酰亚胺中构建多孔结构则是进一步降低介电常数的有效手段。本文从调控分子结构和构建多孔结构的角度出发,综述了化学法制备低介电常数聚酰亚胺的研究进展,并对低介电常数聚酰亚胺的研究前景进行了展望。%With the rapid development of the microelectronics industry, the insulating interlayer material with low dielectric constant is urgently needed in order to improve the speed of transmission between the chips of large scale integrated circuit and meet the requirement of high integration. Polyimide is widely used as the insulating interlayer material in large scale integrated circuit. Reducing dielectric constant of polyimide has attracted much research attention in recent years. When using chemical methods to reduce the dielectric constant, modifying the molecular structures of polyimide is a basic approach. On the other hand, building the porous structure in materials is an effective way to further reduce the dielectric constant of polyimide. In this paper, the recent developments in modifying the molecular structure and building the porous structure are reviewed. Preparation methods of polyimide with low dielectric constant by both methods are summarized and the research prospects in this area are predicted.

  19. La{sub 1−x}Ce{sub x}Mn{sub 1−y}Co{sub y}O{sub 3} perovskite oxides: Preparation, physico-chemical properties and catalytic activity for the reduction of diesel soot

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Shaohua; Song, Chonglin, E-mail: songchonglin@tju.edu.cn; Bin, Feng; Lv, Gang; Song, Jinou; Gong, Cairong

    2014-11-14

    La{sub 1−x}Ce{sub x}Mn{sub 1−y}Co{sub y}O{sub 3} catalysts were prepared by the “glucose method”. The structures and physico-chemical properties for these catalysts were characterized using X-ray diffraction (XRD), nitrogen adsorption, scanning electron microscopy (SEM), Fourier transform infrared spectra (FT-IR), H{sub 2}-temperature-programmed reduction (H{sub 2}-TPR) and O{sub 2}-tempreature-programmed desorption (O{sub 2}-TPD). Results showed that cerium substitution at the A-site in LaMnO{sub 3} produced a CeO{sub 2} phase. The cobalt can be introduced into the B-site in La{sub 0.8}Ce{sub 0.2}MnO{sub 3} at any substitution ratio because of the similar ionic radii between cobalt and manganese. The catalytic activity for soot combustion in air was evaluated using a TG/DTA analyzer. Cerium substitution at A-site enhances the catalytic activity, while cobalt substitution at B-site inhibits the catalytic activity. The activation energy for soot combustion was calculated using the Horowitz method. The activation energy for non-catalytic soot combustion was 164.1 kJ mol{sup −1}. The addition of catalysts decreased the activation energy by about 26–63 kJ mol{sup −1}. Among the applied catalysts, Ce20Mn exhibited the lowest activation energy (101.1 kJ mol{sup −1}). - Highlights: • Cerium substitution at A-site in Mn100 enhances the catalytic activity. • Cerium substitution leads to the formation of the CeO{sub 2} phase. • Cobalt substitution at B-site in Ce20Mn generally decreases the catalytic activity. • Cerium substitution increases the α-O{sub 2} amount and low-temperature reducibility. • Cobalt substitution decreases the α-O{sub 2} amount and low-temperature reducibility.

  20. Diseño de un leudante químico bajo en sodio para preparaciones para la comunidad celíaca Designing a low-sodium chemical leavening for preparations for the celiac community

    Directory of Open Access Journals (Sweden)

    Paula Rossi

    2012-03-01

    Full Text Available Se define Enfermedad Celíaca como una intolerancia permanente a determinadas proteínas que se encuentran en el trigo, la cebada, el centeno y la avena. Las harinas no permitidas para los celíacos son más difíciles de manejar, porque no forman la red proteica de gluten que le confiere a los amasados la característica elasticidad y esponjosidad. En la mayoría de los casos se recurre a ingredientes altos en grasa y sodio. Esta situación resulta de gran importancia para la salud ya que el consumo excesivo de sodio es la principal causa de hipertensión arterial. Con el objetivo de disminuir el contenido de sodio de las preparaciones se ha desarrollado un leudante químico bajo en sodio que, junto a una disminución en el agregado de sal, ha significado un aporte sustantivo en varias recetas de panes consumidos habitualmente por esta población. Se han logrado panes saludables con características sensoriales similares a sus originales que los hacen sumamente aceptables por la población para la cual fueron diseñados.Celiac Disease is defined as a permanent intolerance to certain proteins found in wheat, barley, rye and oats. The flours that are not allowed for coeliacs are more difficult to handle, because they do not form the gluten protein network that gives the dough the characteristic elasticity and sponginess. In most cases ingredients high in fat and sodium are used. This situation is of great importance to health as the excessive consumption of sodium is the main cause of hypertension. In order to reduce the sodium content of the preparations we have developed a lowsodium chemical leavening which, together with a reduction in salt, has contributed substantially in various recipes of breads usually consumed by this population. We have obtained healthy breads with sensory characteristics similar to the original ones that make them highly acceptable in the population for which they were designed.

  1. 冻融联合优化化学法制备粗大去细胞同种异体神经%Preparing acellular nerve allografts by combined freeze-thaw and chemical methods

    Institute of Scientific and Technical Information of China (English)

    管树军; 王伟; 李岩

    2015-01-01

    thoroughly, but the basilar membrane was fuly retained. These findings indicate that the optimized combination of freeze-thaw and chemical methods can efficiently clear Schwann cels and myelin which are the major antigenic components in the peripheral nerve, while preserve the basilar membrane to promote nerve regeneration. Therefore, this method can be an ideal method for preparation of tissue engineered nerves.

  2. Modern Chemical Technology, Volume 1.

    Science.gov (United States)

    Pecsok, Robert L.; Chapman, Kenneth

    This volume is the first in a series of the ACS "Modern Chemical Technology" (ChemTeC) curriculum which is to prepare chemical technicians. The chapters concentrate on gas chromatography, tests for purity, properties of gases, and gas measurements. Included is the appropriate content, exercises, laboratory activities, and all needed mathematics.…

  3. Imprinted photonic crystal chemical sensors

    NARCIS (Netherlands)

    Boersma, A.; Burghoorn, M.M.A.; Saalmink, M.

    2011-01-01

    In this paper we present the use of Photonic Crystals as chemical sensors. These 2D nanostructured sensors were prepared by nano-imprint lithography during which a nanostructure is transferred from a nickel template into a responsive polymer, that is be specifically tuned to interact with the chemic

  4. Graphene composites containing chemically bonded metal oxides

    Indian Academy of Sciences (India)

    K Pramoda; S Suresh; H S S Ramakrishna Matte; A Govindaraj

    2013-08-01

    Composites of graphene involving chemically bonded nano films of metal oxides have been prepared by reacting graphene containing surface oxygen functionalities with metal halide vapours followed by exposure to water vapour. The composites have been characterized by electron microscopy, atomic force microscopy and other techniques. Magnetite particles chemically bonded to graphene dispersible in various solvents have been prepared and they exhibit fairly high magnetization.

  5. Effects of Different Methods of Preparation on the Contents of Chemical Components in Ligustri Lucidi Fructus%不同炮制方法对女贞子化学成分的影响

    Institute of Scientific and Technical Information of China (English)

    肖薇; 黄健; 陈志峰; 郭桂明

    2015-01-01

    Objective To investigate the effects of different methods of preparation on the contents of nuzhenide and oleanolic acid in Ligustri Lucidi Fructus. Methods The same batch of Ligustri Lucidi Fructus was under preparation and process. RP-HPLC was used to determine the contents of nuzhenide and oleanolic acid in crude samples, wine-prepared samples, vinegar-prepared samples, and salt-prepared samples. Results The contents of nuzhenide were in the order as follow:salt-prepared samples (1.997 5%)>crude samples (1.600 7%)>wine-prepared samples (1.144 6%)>vinegar-prepared samples (0.894 6%). The contents of oleanolic acid were in the order as follow:wine-prepared samples (1.120 2%)>salt-prepared samples (0.924 6%)>vinegar-prepared samples (0.913 2%)>crude samples (0.899 8%). Conclusion Different methods of preparation have certain effects on the contents of nuzhenide and oleanolic acid in Ligustri Lucidi Fructus.%目的:考察不同炮制方法对女贞子主要化学成分特女贞苷和齐墩果酸含量的影响。方法用同一批次女贞子进行炮制加工,采用反相高效液相色谱法,对女贞子生品、酒制女贞子、醋制女贞子和盐制女贞子中的特女贞苷和齐墩果酸进行含量测定。结果女贞子生品及3种不同炮制品中特女贞苷含量依次为盐制女贞子(1.9975%)>女贞子生品(1.6007%)>酒制女贞子(1.1446%)>醋制女贞子(0.8946%)。女贞子生品及3种不同炮制品中齐墩果酸含量依次为酒制女贞子(1.1202%)>盐制女贞子(0.9246%)>醋制女贞子(0.9132%)>女贞子生品(0.8998%)。结论女贞子不同炮制方法对其特女贞苷和齐墩果酸的含量有一定影响。

  6. PREPARATION OF HALIDES OF PLUTONIUM

    Science.gov (United States)

    Garner, C.S.; Johns, I.B.

    1958-09-01

    A dry chemical method is described for preparing plutonium halides, which consists in contacting plutonyl nitrate with dry gaseous HCl or HF at an elevated temperature. The addition to the reaction gas of a small quantity of an oxidizing gas or a reducing gas will cause formation of the tetra- or tri-halide of plutonium as desired.

  7. 21 CFR 184.1372 - Insoluble glucose isomerase enzyme preparations.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Insoluble glucose isomerase enzyme preparations... enzyme preparations. (a) Insoluble glucose isomerase enzyme preparations are used in the production of... additional requirements for enzyme preparations in the Food Chemicals Codex, 3d Ed. (1981), p. 107, which...

  8. A Sequential Preparation of Organic Compounds for Senior Chemistry Classes

    Science.gov (United States)

    Merrigan, Cecilia; Crotty, Patricia

    1971-01-01

    Describes procedures suitable for student preparation of benzaldehyde, benzoic acid, and ethyl benzoate sequentially from benzyl alcohol. Preparation for benzyl chloride also given. All reagents except benzyl alcohol are common inorganic chemicals. (AL)

  9. Chemical use

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This is a summary of research and activities related to chemical use on Neal Smith National Wildlife Refuge between 1992 and 2009. The chemicals used on the Refuge...

  10. Chemical Reactors.

    Science.gov (United States)

    Kenney, C. N.

    1980-01-01

    Describes a course, including content, reading list, and presentation on chemical reactors at Cambridge University, England. A brief comparison of chemical engineering education between the United States and England is also given. (JN)

  11. Chemical sensor

    Science.gov (United States)

    Rauh, R. David (Inventor)

    1990-01-01

    A sensor for detecting a chemical substance includes an insertion element having a structure which enables insertion of the chemical substance with a resulting change in the bulk electrical characteristics of the insertion element under conditions sufficient to permit effective insertion; the change in the bulk electrical characteristics of the insertion element is detected as an indication of the presence of the chemical substance.

  12. Chemical and ecological health of white sucker (Catostomus commersoni) in Rock Creek Park, Washington, D.C., 2003-04 / by Cherie V. Miller ... [et al.] ; prepared in copoeration with the National Park Service

    OpenAIRE

    Miller, Cherie V.; Weyers, Holly S.; Blazer, Vicki S.; Freeman, Mary E.

    2009-01-01

    Several classes of chemicals that are known or suspected contaminants were found in bed sediment in Rock Creek, including polyaromatic hydrocarbons (PAHs), phthalate esters, organochlorine pesticides, dioxins and furans, trace metals and metalloids (mercury, arsenic, cadmium, chromium, cobalt, copper, lead, nickel, silver, and zinc), and polychlorinated biphenyls (total PCBs and selected aroclors). Concentrations of many of these chemicals consistently exceeded thresholdor chronic-effects gui...

  13. Chemical Leukoderma.

    Science.gov (United States)

    Bonamonte, Domenico; Vestita, Michelangelo; Romita, Paolo; Filoni, Angela; Foti, Caterina; Angelini, Gianni

    2016-01-01

    Chemical leukoderma, often clinically mimicking idiopathic vitiligo and other congenital and acquired hypopigmentation, is an acquired form of cutaneous pigment loss caused by exposure to a variety of chemicals that act through selective melanocytotoxicity. Most of these chemicals are phenols and aromatic or aliphatic catechols derivatives. These chemicals, however, are harmful for melanocytes in individuals with an individual susceptibility. Nowadays, chemical leukoderma is fairly common, caused by common domestic products. The presence of numerous acquired confetti- or pea-sized macules is clinically characteristic of chemical leukoderma, albeit not diagnostic. Other relevant diagnostic elements are a history of repeated exposure to a known or suspected depigmenting agent at the sites of onset and a macules distribution corresponding to sites of chemical exposure. Spontaneous repigmentation has been reported when the causative agent is avoided; the repigmentation process is perifollicular and gradual, taking place for a variable period of weeks to months. PMID:27172302

  14. 批量制备Fe2O3/Al2O3氧载体及褐煤化学链燃烧实验研究%Batch Preparation of Fe2O3/Al2O3 Oxygen Carriers for Chemical Looping Combustion of Lignite

    Institute of Scientific and Technical Information of China (English)

    郭磊; 赵海波; 马琎晨; 梅道锋; 方彦飞; 郑楚光

    2013-01-01

    Freeze granulation,spray drying,impregnation and mechanical mixing methods were adopted to prepare Fe2O3/Al2O3 oxygen carriers.To identify the appropriate technologies for batch preparation of the oxygen carriers,the four preparation methods were compared in terms of yield rate,preparation period,physical and chemical characteristics and performance in chemical looping combustion (CLC) of lignite.The experimental results show that freeze granulation has the highest yield rate of carrier with the best mechanical strength.CLC tests of lignite demonstrate that the oxygen carriers prepared by freeze granulation and spray drying bring the highest carbon conversion rate,followed by impregnation and mechanical mixing; and the oxygen carriers prepared by the first two methods have higher chemical reactivity and more stable performance.In the four reduction processes with oxygen carriers prepared by all the four preparation methods,CO2 capture efficiencies exceed 88%; the yield rate of CO2 increases with the rate of carbon conversion,finally approaching 100%; and the combustion efficiencies are above 90%.These indicate that the oxygen carriers prepared by the four methods all have good performances for CO2 capture and high utilization degree of the combustible components.Freeze granulation and spray drying methods can be considered preferentially for batch preparation of oxygen carriers for the CLC of lignite.%采用冷冻成粒法、喷雾干燥法、浸渍法、机械混合法批量制备了Fe2O3/Al2O3氧载体,从氧载体产率、制备周期、物理化学表征、煤化学链燃烧中氧载体性能等角度比较各种批量制备方法,确定合适的批量制备技术.实验结果表明,冷冻成粒法的氧载体产率较高,机械性能最优;与褐煤的化学链燃烧实验中,喷雾干燥法和冷冻成粒法制备的氧载体导致碳转化速率较快,然后依次为浸渍法和机械混合法;且前两种方法制备的氧载体的循环稳定性

  15. Chemical networks*

    OpenAIRE

    Thi Wing-Fai

    2015-01-01

    This chapter discusses the fundamental ideas of how chemical networks are build, their strengths and limitations. The chemical reactions that occur in disks combine the cold phase reactions used to model cold molecular clouds with the hot chemistry applied to planetary atmosphere models. With a general understanding of the different types of reactions that can occur, one can proceed in building a network of chemical reactions and use it to explain the abundance of species seen in disks. One o...

  16. AFFINITY OF LIGNIN PREPARATIONS TOWARDS GENOTOXIC COMPOUNDS

    Directory of Open Access Journals (Sweden)

    Božena Košíková

    2009-02-01

    Full Text Available The carcinogenicity and mutagenicity of chemicals may be modulated by other chemicals, including those prepared by organic synthesis. Consid-ering the several drawbacks of synthetic compounds vis-a-vis the human organism, the lignin biomass component was examined for this purpose. The binding affinity of lignin samples prepared by chemical and biological modification of lignin products derived from chemical wood treatment towards for N-nitrosodiethylamine (NDA was examined. The protective role of the lignin samples against carcinogenesis was tested on a well-known model carcinogen, N-methyl-N´-nitro-N-nitrosoguanidine (MNNG. The observed ability of a series of lignin preparations to reduce alkylation damage of deoxyribonucleic acid (DNA on hamster cells in vitro could be explained by their affinity to bind N-nitrosoamines. The results indicate that lignin has potential to protect living organisms against damaging effects of different genotoxicants.

  17. Chemical sensors

    Science.gov (United States)

    Lowell, J.R. Jr.; Edlund, D.J.; Friesen, D.T.; Rayfield, G.W.

    1991-07-02

    Sensors responsive to small changes in the concentration of chemical species are disclosed. The sensors comprise a mechanochemically responsive polymeric film capable of expansion or contraction in response to a change in its chemical environment. They are operatively coupled to a transducer capable of directly converting the expansion or contraction to a measurable electrical response. 9 figures.

  18. Chemical Radioprotectors

    Directory of Open Access Journals (Sweden)

    S. N. Upadhyay

    2005-10-01

    Full Text Available Protection of biological systems against radiation damage is of paramount importance during accidental and unavoidable exposure to radiation. Several physico-chemical and biological factors collectively contribute to the damage caused by radiation and are, therefore, targets for developing radioprotectors. Work on the development of chemicals capable of protecting biological systemsfrom radiation damage was initiated nearly six decades ago with cysteine being the first molecule to be reported. Chemicals capable of scavenging free radicals, inducing oxygen depletion,antioxidants and modulators of immune response have been some of the radioprotectors extensively investigated with limited success. Mechanism of action of some chemical radioprotectors and their combinations have been elucidated, while further understanding is required in many instances. The present review elaborates on structure-activity relationship of some of the chemical radioprotectors, their evaluation, and assessment, limitation, and future prospects.

  19. Physical-Chemical Characterization of Nanodispersed Powders Produced by a Plasma-Chemical Technique

    Institute of Scientific and Technical Information of China (English)

    M. GEORGIEVA; G. VISSOKOV; Iv. GRANCHAROV

    2007-01-01

    This article presents a review on the physical-chemical properties and characteristics of plasma-chemically produced nanodispersed powders (NDP), such as metals, oxides, nitrides, carbides, and catalysts. The plasma-chemical preparation of the powders was carried out in thermal plasma (TP) created by means of high-current electric arcs, plasma jets, high-frequency (HF) discharges, etc. We also discuss certain properties and characteristics of the NDPs, which are determined largely by the conditions of preparation.

  20. Biological and Chemical Security

    Energy Technology Data Exchange (ETDEWEB)

    Fitch, P J

    2002-12-19

    The LLNL Chemical & Biological National Security Program (CBNP) provides science, technology and integrated systems for chemical and biological security. Our approach is to develop and field advanced strategies that dramatically improve the nation's capabilities to prevent, prepare for, detect, and respond to terrorist use of chemical or biological weapons. Recent events show the importance of civilian defense against terrorism. The 1995 nerve gas attack in Tokyo's subway served to catalyze and focus the early LLNL program on civilian counter terrorism. In the same year, LLNL began CBNP using Laboratory-Directed R&D investments and a focus on biodetection. The Nunn-Lugar-Domenici Defense Against Weapons of Mass Destruction Act, passed in 1996, initiated a number of U.S. nonproliferation and counter-terrorism programs including the DOE (now NNSA) Chemical and Biological Nonproliferation Program (also known as CBNP). In 2002, the Department of Homeland Security was formed. The NNSA CBNP and many of the LLNL CBNP activities are being transferred as the new Department becomes operational. LLNL has a long history in national security including nonproliferation of weapons of mass destruction. In biology, LLNL had a key role in starting and implementing the Human Genome Project and, more recently, the Microbial Genome Program. LLNL has over 1,000 scientists and engineers with relevant expertise in biology, chemistry, decontamination, instrumentation, microtechnologies, atmospheric modeling, and field experimentation. Over 150 LLNL scientists and engineers work full time on chemical and biological national security projects.

  1. Hazardous Chemicals

    Centers for Disease Control (CDC) Podcasts

    2007-04-10

    Chemicals are a part of our daily lives, providing many products and modern conveniences. With more than three decades of experience, The Centers for Disease Control and Prevention (CDC) has been in the forefront of efforts to protect and assess people's exposure to environmental and hazardous chemicals. This report provides information about hazardous chemicals and useful tips on how to protect you and your family from harmful exposure.  Created: 4/10/2007 by CDC National Center for Environmental Health.   Date Released: 4/13/2007.

  2. Chemical Peels

    Science.gov (United States)

    ... pills, who subsequently become pregnant or have a history of brownish facial discoloration. Scarring Reactivation of cold sores What can I expect after having a chemical peel? All peels require some follow-up care: ...

  3. Unnecessary Chemicals

    Science.gov (United States)

    Johnson, Anita

    1978-01-01

    Discusses the health hazards resulting from chemical additions of many common products such as cough syrups, food dyes, and cosmetics. Steps being taken to protect consumers from these health hazards are included. (MDR)

  4. PREPARATION OF ACTIVATED CARBON FROM PALM OIL SHELL BY CHEMICAL ACTIVATION WITH Na2CO3 AND ZnCl2 AS IMPRENATED AGENTS FOR H2S ADSORPTION

    Directory of Open Access Journals (Sweden)

    Kanokorn Hussaro

    2014-01-01

    Full Text Available Hydrogen Sulfide (H2S, rotten-egg is one of the major environmental pollutants having its sources in natural and anthropogenic activities. It’s had smell gas produced by anaerobic digestion in acid condition from organic and inorganic compounds containing sulphur, presents dual problems of its toxicity and foul ordour. One of methods of its removal is adsorption. Activated carbon is a widely used adsorbent in the treatment of air pollution. Adsorption type and capacity are primarily based on the physical properties of pores, namely the surface area. Convetionnally, activated carbon is produced from biomass residues, wood coal and agricultural residuces. Today, one promising approach for the production of cheap and efficient activated carbon is used of waste from palm oil mill industries, which is palm oil shell. Palm oil shell is available in large quantities of approximately 0.53 million tonnes annually in Thailand. Palm oil shell is a by-products of the palm oil industry and was used as a raw material in this study due to its high carbon content, high density and low ash content. Normally, H2S in biogas, which is found the range between as low as about 50-10,000 ppm depending on the feed material composition to prodction, can cause corrosion to engine and metal substance via of SO2 from combustion. H2S must be removed from biogas product prior to further utilization. Therefore, in these research the usage of palm oil shell is especially important due to its high value added for produced activated carbon adsorbent for H2S adsorption in biogas product. In this study, fixed bed reactor (stainless steel with 54.1 mm internal diameter and 320 mm length was studied to observe the effect of char product: Chemical agent ratio (Na2CO3 and ZnCl2, 1:1 to 1:3, which there are activated at 700°C activation temperature for 2 h on the chemical and physical properties

  5. The research and preparation of an instant chemical deoxidizer—HCY and its%工业锅炉HCY速效化学除氧剂及加药器的研制

    Institute of Scientific and Technical Information of China (English)

    马铭杰; 王德林

    2001-01-01

    A new kind of instant chemical deoxidizer and its doser for industrial low-pressure boiler and heating network system have been made,which can improve chemical reaction speed of deoxidization under the condition of the water supplied in normal temperature,and make the water reach the state without dissolved oxygen before entering the boiler. The doser whose structure is simple and easy to manage can complete a course of feeding continuously,automatically,uniformly and quantitatively.%研制了一种速效化学除氧剂及新型加药器,用于工业低压锅炉及热网系统,能够提高锅炉常温给水情况下的除氧化学反应速度,使给水在进锅炉前即达到无氧状况;加药器结构简单,管理方便,可实现连续自动均匀定量的加药过程。

  6. 重大化学灾害事件医学应急救援预案的准备%Preparation of contingency plan of emergency medical response team for catastrophic chemical disasters

    Institute of Scientific and Technical Information of China (English)

    赵建; 丁日高

    2016-01-01

    在各类灾害事件处置和救援过程中,应急救援预案是一切行动的核心,是各种具体行动有序、高效展开,以及减少事故影响和损失最为有效的保证。本文拟以“天津港8·12特大爆炸事故”为背景,分析重大化学灾害事件医学应急救援预案准备过程中应关注的重要因素,并对预案内容提出具体建议。%In the management of disasters of any kinds,including the catastrophic chemical disasters,the contingency plan is,definitely,a saga for the efficient practice of the detailed and technically sophisticated rescue work,which is a guarantee for mini⁃mizing the negative impacts and loses of various kinds induced by the disaster. Backgrounded on the“Tianjin Port 8 · 12 Catastrophic Explosion Accident”,which was heavily involved with large amounts of chemicals of many kinds,key planning factors to be consid⁃ered in making the contingency plan for the emergency medical response team are discussed,and suggestions for some of the details within a certain kind of a plan are also provided.

  7. Recommended Inorganic Chemicals for Calibration.

    Science.gov (United States)

    Moody, John R.; And Others

    1988-01-01

    All analytical techniques depend on the use of calibration chemicals to relate analyte concentration to instrumental parameters. Discusses the preparation of standard solutions and provides a critical evaluation of available materials. Lists elements by group and discusses the purity and uses of each. (MVL)

  8. Optimization of chemical analysis methods for coal and fly ash. 1. Sampling, sample preparation and 'proximate' analysis. Optimalisatie analysemethoden voor steenkool en vliegas. 1. Monstername, monsterverwerking en 'proximate' analyse

    Energy Technology Data Exchange (ETDEWEB)

    Hissink, M.

    1983-01-01

    To support the experiments in the atmospheric fluid bed boiler (AFBB) many analyses of samples of fuel, additions and waste are needed. Therefore it was necessary to obtain experience with regard to sampling, sample preparation and analysis of these materials. For a correct interpretation of the experiments in the AFBB a knowledge of the accuracy of the results of these analyses is essential. This accuracy depends largely on the sampling method. As a guide for the methods to be used the instructions in the relevant ISO Standards have been followed usually. A description is given of the procedures for sampling and analysis as well as of the equipment used. The accuracy that can be expected for the various results of analysis has been established experimentally. It was found in general that the requirements were met.

  9. Optimization of chemical analysis methods for coal and fly ash. 1. Sampling, sample preparation and proximate analysis. Optimalisatie analysemethoden voor steenkool en vliegas. 1. Monstername monsterverwerking en 'proximate' analyse

    Energy Technology Data Exchange (ETDEWEB)

    Hissink, M.

    1983-01-01

    To support the experiments in the atmospheric fluid bed boiler (AFBB), many analyses of samples of fuel, additives and waste are needed. Therefore it was necessary to obtain experience with regard to sampling, sample preparation and analysis of these materials. For a correct interpretation of the experiments in the AFBB, a knowledge of accuracy of the results of these analyses is essential. This accuracy depends largely on the sampling method. As a guide for the methods to be used, the instructions in the relevant ISO Standards have been followed usually. A description is given of the procedures for sampling and analysis as well as of the equipment used. The accuracy that can be expected for the various results of analysis has been established experimentally. It was found in general that the requirements were met. (In Dutch)

  10. 放热体系对镁合金反应热喷涂陶瓷涂层耐蚀性能的影响%Influence of exothermic chemical system on corrosion resistance of reaction thermal spraying ceramic coating prepared on magnesium alloy

    Institute of Scientific and Technical Information of China (English)

    董世知; 周鹏; 宋佳; 窦梓航; 于浩

    2012-01-01

    Influence of exothermic chemical system on corrosion resistance of ceramic coatings prepared by reaction thermal-spraying method with the same aggregate and different exothermic chemical system A1/CuO and A1-TiO2-B203 was studied by comparing morphology, XRD, porosity, acid-resistance (5% acetic acid solution), salt-resistance (3.5 % NaC1 solution) respectively. The test results show that compared to matrix AZ31 B, corrosion-resistance of ceramic coating with A1/CuO exothermic chemical system is improved by 23.37 and 16.33 times, whereas A1-TiO2-B203 exothermic chemical system just about 12.91 and 7.46 times. Ceramic coating with A1/CuO exothermic chemical system exhibits better corrosion-resistance than A1-TiO2-B203 exothermic chemical system.%采用相同的陶瓷骨料和热喷涂工艺,放热体系分别为Al/CuO和Al-TiO2-B2O3,制备热喷涂陶瓷涂层,通过对涂层表面形貌观察、物相分析、孔隙率,耐酸性(5%醋酸),耐盐性(3.5%NaCl)测试比较放热体系对陶瓷涂层耐蚀性能影响。结果表明:与基体AZ31B相比,采用Al-CuO为放热体系的陶瓷涂层耐酸性提高23.37倍,耐盐性提高16.33倍,Al-TiO2-B2O3放热体系陶瓷涂层的耐酸性提高12.91倍,耐盐性提高7.46倍,Al-CuO放热体系陶瓷涂层耐蚀性优于Al-TiO2-B2O3放热体系陶瓷涂层。

  11. Chemical Mahjong

    Science.gov (United States)

    Cossairt, Travis J.; Grubbs, W. Tandy

    2011-01-01

    An open-access, Web-based mnemonic game is described whereby introductory chemistry knowledge is tested using mahjong solitaire game play. Several tile sets and board layouts are included that are themed upon different chemical topics. Introductory tile sets can be selected that prompt the player to match element names to symbols and metric…

  12. Chemical Peels

    Science.gov (United States)

    ... resources Meet our partners Español Donate Diseases and treatments Acne and rosacea Bumps and growths Color problems Contagious skin diseases ... Chemical peels public SPOT Skin Cancer™ Diseases and treatments Acne and rosacea Bumps and growths Color problems Contagious skin diseases ...

  13. Chemical pressure

    OpenAIRE

    Hauser, Andreas; Amstutz, Nahid; Delahaye, Sandra; Sadki, Asmaâ; Schenker, Sabine; Sieber, Regula; Zerara, Mohamed

    2002-01-01

    The physical and photophysical properties of three classic transition metal complexes, namely [Fe(bpy)3]2+, [Ru(bpy)3]2+, and [Co(bpy)3]2+, can be tuned by doping them into a variety of inert crystalline host lattices. The underlying guest-host interactions are discussed in terms of a chemical pressure.

  14. Chemical dispersants

    NARCIS (Netherlands)

    Rahsepar, Shokouhalsadat; Smit, Martijn P.J.; Murk, Albertinka J.; Rijnaarts, Huub H.M.; Langenhoff, Alette A.M.

    2016-01-01

    Chemical dispersants were used in response to the Deepwater Horizon oil spill in the Gulf of Mexico, both at the sea surface and the wellhead. Their effect on oil biodegradation is unclear, as studies showed both inhibition and enhancement. This study addresses the effect of Corexit on oil biodeg

  15. Microfabrication, separations, and detection by mass spectrometry on ultrathin-layer chromatography plates prepared via the low-pressure chemical vapor deposition of silicon nitride onto carbon nanotube templates.

    Science.gov (United States)

    Kanyal, Supriya S; Häbe, Tim T; Cushman, Cody V; Dhunna, Manan; Roychowdhury, Tuhin; Farnsworth, Paul B; Morlock, Gertrud E; Linford, Matthew R

    2015-07-24

    Microfabrication of ultrathin-layer chromatography (UTLC) plates via conformal deposition of silicon nitride by low-pressure chemical vapor deposition onto patterned carbon nanotube (CNT) scaffolds was demonstrated. After removal of the CNTs and hydroxylation, the resulting UTLC phase showed no expansion or distortion of their microfeatures and the absence/reduction of remaining nitrogenic species. Developing time of a mixture of lipophilic dyes on this UTLC plates was 86% shorter than on high-performance thin-layer chromatography (HPTLC) plates. A water-soluble food dye mixture was also separated resulting in low band broadening and reduced developing time compared to HPTLC. For the latter example, mobile phase optimization on a single UTLC plate consisted of 14 developments with different mobile phases, each preceded by a plate prewashing step. The same plate was again reused for additional 11 separations under varying conditions resulting in a development procedure with a mean separation efficiency of 233,000theoretical plates/m and a reduced mobile phase consumption of only 400μL. This repeated use proved the physical robustness of the ultrathin layer and its resistance to damage. The layer was highly suited for hyphenation to ambient mass spectrometry, including desorption electrospray ionization (DESI) mass spectrometry imaging and direct analysis in real time (DART) mass spectrometry.

  16. Characterization of photoluminescent (Y{sub 1{minus}x}Eu{sub x}){sub 2}O{sub 3} thin-films prepared by metallorganic chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    McKittrick, J.; Bacalski, C.F.; Hirata, G.A. [Univ. of California, San Diego, La Jolla, CA (United States); Hubbard, K.M.; Pattillo, S.G.; Salazar, K.V.; Trkula, M. [Los Alamos National Lab., NM (United States). Materials Science and Technology Div.

    1998-12-01

    Europium doped yttrium oxide, (Y{sub 1{minus}x}Eu{sub x}){sub 2}O{sub 3}, thin-films were deposited on silicon and sapphire substrates by metallorganic chemical vapor deposition (MOCVD). The films were grown in a MOCVD chamber reacting yttrium and europium tris(2,2,6,6-tetramethyl-3,5,-heptanedionates) precursors in an oxygen atmosphere at low pressures (5 Torr) and low substrate temperatures (500--700 C). The films deposited at 500 C were flat and composed of nanocrystalline regions of cubic Y{sub 2}O{sub 3}, grown in a textured [100] or [110] orientation to the substrate surface. Films deposited at 600 C developed from the flat, nanocrystalline morphology into a plate-like growth morphology oriented in the [111] with increasing deposition time. Monoclinic Y{sub 2}O{sub 3}:Eu{sup 3+} was observed in x-ray diffraction for deposition temperatures {ge}600 C on both (111) Si and (001) sapphire substrates. This was also confirmed by the photoluminescent emission spectra.

  17. New Inorganic-organic Hybrid Compound Containing One Dimensional Keggin Polyoxometalate[SiW11O39Co]6- Chains:Preparation,Characterization and Application in Chemically Bulk-modified Electrode

    Institute of Scientific and Technical Information of China (English)

    WANG Xiu-li; LIN Hong-yan; LIU Guo-cheng; CHEN Bao-kuan; BI Yan-feng

    2008-01-01

    A new inorganic-organic hybrid compound based on polyoxometalate and organic ligand formulated as (H2bpp)3[SiW11O39Co]~2H2O(1)[bpp=1,3-bis(4-pyridyl)propane]was hydrothermally synthesized and structurally characterized by elemental analysis,single-crystal X-ray diffraction,IR,TG,and cyclic voltammetry.Single-crystal X-ray diffraction analysis reveals that compound 1 consists of interesting cobalt-monosubstituted POMs one dimensional chain together with protonated bpp ligands.Additionally,the polyoxoanions combined with the discrete organic substrates by hydrogen bond interactions to afford a supramolecular 3D network structure.The hybrid compound 1 was used as a bulk modifier to fabricate a three-dimensional chemically modified carbon paste electrode(1-CPE)by direct mixing.The electrochemical behavior and electrocatalysis of 1-CPE were studied in detail.The results indicate that 1-CPE has good electrocatalytic activities toward the reduction of nitrite or bromate in 1mol/L H2SO4 aqueous solution.1-CPE shows remarkable stability that can be ascribed to the insolubility of compound 1 and the supramolecular interactions existed between 1D POM anion chains and organic ligand bpp,which is very important for practical applications in electrode modification.

  18. Obtenção e caracterização de materiais argilosos quimicamente ativados para utilização em catálise Preparation and characterization of chemically activated clays for use in catalysis

    Directory of Open Access Journals (Sweden)

    M. G. F. Rodrigues

    2006-12-01

    Full Text Available O principal objetivo deste trabalho é caracterizar argilas esmectíticas "Chocolate" de Boa-Vista, PB, tanto na sua forma natural quanto tratada quimicamente, visando sua aplicação em catálise. As argilas foram caracterizadas por fluorescência de raios X, difração de raios X e espectrofotometria de absorção óptica na região do infravermelho. Os resultados mostraram que o tratamento ácido alterou a estrutura da montmorilonita. A reação de isomerização do meta-xileno, para o material ativado, mostrou que a argila ácida foi mais ativa que a natural.The main objective of this paper is to characterize the chocolate smectite clays of Boa-Vista, PB, Brazil, in their natural form, and after chemical treatment, for their application in catalysis. The experimental methods were: X-ray fluorescence, X-ray diffraction and infrared spectroscopy. The results show that the acid treatment altered the montimorillonite structure. The obtained reaction (isomerization of m-xylene for the treated material showed that treated clays were more active than the natural ones.

  19. 紫菜多糖Fe(Ⅲ)配合物的制备及其理化性质%STUDY ON PREPARATION AND CHEMICAL CHARACTERIZATION OF IRON(Ⅲ)—PORPHYRA POLYSACCHARIDE COMPLEX

    Institute of Scientific and Technical Information of China (English)

    孟凡德; 赵全芹; 刘学启; 李明霞; 刘洛生

    2001-01-01

    目的:从紫菜中提取多糖,然后与Fe(Ⅲ)合成一种新型的营养补铁剂。方法:合成紫菜多糖Fe(Ⅲ)配合物(PTC),并测定其相应的理化性质。结果:PTC的水溶液中不存在游离的Fe(Ⅲ),表明Fe(Ⅲ)与紫菜多糖形成了稳定的配合物。PTC在pH 7.34的生理盐水中不沉、不水解;动力学实验表明PTC中的Fe(Ⅲ)易被还原。经红外光谱分析,PTC是以β-(FeOOH)n为微核,紫菜多糖在核表面形成化合物。结论:PTC有望成为较好生物利用度的营养型补铁剂。%OBJECTIVE:Porphyra polysaccharide isolated from Porphyra,then iron(Ⅲ)-porphyra polysaccharide(PTC)complex was synthesized with FeCl3 and porphyra polysaccharied.METHODS:A new kind of iron-supplementary drug has been prepared.RESULTS:Experiment showed that porphyra polysaccharied iron(Ⅲ)complex was able to be dissolve in water and its solution assumed neutral,and this complex has no precipitate at pH to 11,therefore,this complex was very stable.The investigation by infrared spectra indicated that the structure of porphyra polysaccharide iron(Ⅲ)had been an interfacial complex with β-(FeOOH)ncore.Because this complex was not precipitated and dissociated at the physiological pH=7.34.CONCLUSION:Porphyra polysaccharide iron(Ⅲ) complex was able to become higher bioavailability and nutrition iron-supplementary.

  20. Rare earths: preparation of spectro chemically pure standards, study of their carbonates and synthesis of a new compound series - the peroxy carbonates; Terras-raras: obtencao de padroes espectroquimicos, estudo dos carbonatos e sintese dos peroxicarbonatos. Uma nova serie de compostos

    Energy Technology Data Exchange (ETDEWEB)

    Queiroz, Carlos Alberto da Silva

    1996-05-01

    In this work the following studies are concerned: I) preparation of lanthanum, cerium, praseodymium, neodymium and samarium oxides for use as spectro chemically pure standards; II) behavior of the rare earth (La, Ce, Pr, Nd, Sm) carbonates soluble in ammonium carbonate and mixture of ammonium carbonate/ammonium hydroxide, and III) synthesis and characterization of rare earth peroxy carbonates - a new series of compounds. Data for the synthesis and characterization of the rare earths peroxy carbonates described for the first time in this work are presented and discussed. With the aid of thermal analysis (TG-DTG) the thermal stability and the stoichiometric composition for new compounds were established and a mechanism of thermal decomposition was proposed. The peroxy carbonate was prepared by the addition of hydrogen peroxyde to the complexed soluble rare earths carbonates. These studies included also the determinations of active oxygen, the total rare earth oxide by gravimetry and complexometry and the C, H and N contents by microanalysis. The new compounds were also investigated by infrared spectroscopy. (author)

  1. Influence of hydrogen dilution on structural, electrical and optical properties of hydrogenated nanocrystalline silicon (nc-Si:H) thin films prepared by plasma enhanced chemical vapour deposition (PE-CVD)

    Energy Technology Data Exchange (ETDEWEB)

    Funde, A.M.; Bakr, Nabeel Ali; Kamble, D.K. [School of Energy Studies, University of Pune, Pune 411 007 (India); Hawaldar, R.R.; Amalnerkar, D.P. [Center for Materials for Electronics Technology (C-MET), Panchawati, Pune 411 008 (India); Jadkar, S.R. [Department of Physics, University of Pune, Ganeshkhind Road, Pune 411 007 (India)

    2008-10-15

    Hydrogenated nanocrystalline silicon (nc-Si:H) thin films were deposited from pure silane (SiH{sub 4}) and hydrogen (H{sub 2}) gas mixture by conventional plasma enhanced chemical vapour deposition (PE-CVD) method at low temperature (200 C) using high rf power. The structural, optical and electrical properties of these films are carefully and systematically investigated as a function of hydrogen dilution of silane (R). Characterization of these films with low angle X-ray diffraction and Raman spectroscopy revealed that the crystallite size in the films tends to decrease and at same time the volume fraction of crystallites increases with increase in R. The Fourier transform infrared (FTIR) spectroscopic analysis showed at low values of R, the hydrogen is predominantly incorporated in the nc-Si:H films in the mono-hydrogen (Si-H) bonding configuration. However, with increasing R the hydrogen bonding in nc-Si:H films shifts from mono-hydrogen (Si-H) to di-hydrogen (Si-H{sub 2}) and (Si-H{sub 2}){sub n} complexes. The hydrogen content in the nc-Si:H films decreases with increase in R and was found less than 10 at% over the entire studied range of R. On the other hand, the Tauc's optical band gap remains as high as 2 eV or much higher. The quantum size effect may responsible for higher band gap in nc-Si:H films. A correlation between electrical and structural properties has been found. For optimized deposition conditions, nc-Si:H films with crystallite size {proportional_to}7.67 nm having good degree of crystallinity ({proportional_to}84%) and high band gap (2.25 eV) were obtained with a low hydrogen content (6.5 at%). However, for these optimized conditions, the deposition rate was quite small (1.6 Aa/s). (author)

  2. Controle químico de arroz vermelho no sistema de preparo do solo por inundação em Santa Catarina Chemical control of red rice for the submerged soil preparation system, in Santa Catarina

    Directory of Open Access Journals (Sweden)

    M.G. Ramos

    1982-06-01

    Full Text Available Este trabalho foi desenvolvido para se encontrar um método de controle químico do arroz. Os experimentos foram realizados na Região do Baixo Vale do Itajaí, nos anos de 1978 e 1980. Os herbicidas 2,4-D amina, benthiocarb, oxadiazon, metolachlor e alachlor, quando aplicados em quadros inundados e, com 13 e 15 dias de antecedência à semeadura do aroz cultivado, apresentaram controle de arroz vermelho acima de 75% e controle total das plantas daninhas comuns da área. A população do arroz cultivado não foi afetada com a aplicação desses herbicidas. As produções alcançadas, com a aplicação desses herbicidas foi variável e dependia do nível de infestação de arroz vermelho e das outras plantas daninhas.To study the efficiency of the chemical method for red rice control three field experi ments were carried out at Low Itajai Valley in the years 1978 and 1980. The herbicides 2,4-D amine, benthiocarb, oxadiazon, metolachlor, and alachlor were applied on submerged fields, 13 to 15 days before the seeding of the cultivated rice. The control cf red rice was over 75 % and total for the other common weeds with the herbicides. None of the herbicides caused any damage to the cultivated rice. The yields for rice were depending on the level of red rice and other weeds infestation.

  3. Preparation of multichannel Zr02 ultrafilration membrane with suspension derived from wet chemical synthesis%湿化学法制备多通道ZrO2超滤膜

    Institute of Scientific and Technical Information of China (English)

    周邢; 邱鸣慧; 范益群

    2011-01-01

    Zirconia ultrafiltration membranes were fabricated by the wet chemical route.The multichannel zirconia mierofiltration membrane with the pore size of 200 nm served as the substrate, and zireonia nanoparticle suspension was used to form the membrane layer.The effects of sintering temperature on the microstrueture were investigated by X-ray diffraction (XRD) analysis and nitrogen adsorption/desorption.The morphology of the membrane was analyzed by scanning electron microscope (SEM).The permeation and separation performances of the membranes were evaluated by cross-section filtration.The results showed that the membranes were crack-free when the sintering temperature was controlled at 600 ℃.The membrane had higher pure water flux and the molecular weight cut off (MWCO) was 20 000 for multichannel zirconia membrane.The retention rate of the egg albumin (Mw =43 000) reached 95%.%采用孔径为200nm的多通道ZrO2膜为底膜,利用湿化学法制备小孔径ZrO2超滤膜.结合N2吸附-脱附法和X线衍射分析,考察烧结温度对膜结构的影响,确定合适的烧结温度.通过扫描电镜(SEM)表征膜形貌,采用错流过滤考察膜的渗透和分离性能.结果表明:烧结温度为600℃时可以制备完整无缺陷的ZrO2超滤膜,所制备的超滤膜具有高纯水通量,截留相对分子质量(MWCO)为20 000,对相对分子质量为43 000卵清蛋白的截留率达到96%.

  4. Synthesis, characterization and study of magnetic, electrical and dielectric properties of La{sub 1−x}Dy{sub x}Co{sub 1−y}Fe{sub y}O{sub 3} nanoparticles prepared by wet chemical route

    Energy Technology Data Exchange (ETDEWEB)

    Choudhry, Qurshia [Department of Chemistry, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan); Azhar Khan, Muhammad [Department of Physics, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan); Nasar, Gulfam; Mahmood, Azhar; Shahid, Muhammad [Department of Chemistry, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan); Shakir, Imran [Deanship of Scientific Research, College of Engineering, PO Box 800, King Saud University, Riyadh 11421 (Saudi Arabia); Farooq Warsi, Muhammad, E-mail: farooq.warsi@iub.edu.pk [Department of Chemistry, The Islamia University of Bahawalpur, Bahawalpur 63100 (Pakistan)

    2015-11-01

    Dy{sup 3+} and Fe{sup 3+} co-doped LaCoO{sub 3} perovskite nanoparticles were prepared by chemical co-precipitation route. Structural elucidation was carried out by thermo gravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectroscopy. The data of all these characterization techniques confirmed the orthorhombic phase with particles size in the range of 20–60 nm. The magnetic parameters, DC-resistivity and dielectric properties were measured for La{sub 1−x}Dy{sub x}Co{sub 1−y}Fe{sub y}O{sub 3} nanoparticles. The purpose of all these application studies was to evaluate the prepared materials for practical applications. The substitution of Dy{sup 3+} and Fe{sup 3+} with La{sup 3+} and Co{sup 3+} respectively greatly influenced the magnetic, DC-resistivity and dielectric parameters. - Highlights: • La{sub 1−x}Dy{sub x}Co{sub 1−y}Fe{sub y}O{sub 3} nanoparticles were prepared in the range 20–60 nm. • 12 Fold increase in DC resistivity achieved for La{sub 0.40}Dy{sub 0.60}Co{sub 0.40}Fe{sub 0.60}O{sub 3.} • Paramagnetic to ferromagnetic behavior was observed for La{sub 1−x}Dy{sub x}Co{sub 1−y}Fe{sub y}O{sub 3} nanoparticles.

  5. THE USE OF CHEMICALS IN THE FIELD OF FARM ANIMAL HEALTH (NUTRITION, ENTOMOLOGY, PATHOLOGY). AGRICULTURAL CHEMICALS TECHNOLOGY, NUMBER 7.

    Science.gov (United States)

    Ohio State Univ., Columbus. Center for Vocational and Technical Education.

    DEVELOPED BY A NATIONAL TASK FORCE ON THE BASIS OF STATE STUDIES, THIS MODULE IS ONE OF A SERIES DESIGNED TO ASSIST TEACHERS IN PREPARING POST-SECONDARY STUDENTS FOR AGRICULTURAL CHEMICAL OCCUPATIONS. THE SPECIFIC OBJECTIVE OF THIS MODULE IS TO PREPARE TECHNICIANS IN THE FIELD OF THE USE OF CHEMICALS FOR ANIMAL HEALTH. SECTIONS INCLUDE -- (1)…

  6. Preparation of thin nuclear targets

    International Nuclear Information System (INIS)

    Thin film backings, sources and targets are needed for many applications in low energy nuclear physics and nuclear chemistry experiments. A survey of techniques used in the preparation of nuclear targets is first briefly discussed. These are classified as chemical, mechanical and physical preparations. Vacuum evaporation, being the most generally used technique, is discussed in detail. It is highly desirable to monitor the film thickness and control the deposition rate during evaporation and to measure the final target thickness after deposition has concluded. The relative merits of various thickness measuring techniques are described. Stages in the fabrication and mounting of self-supporting foils are described in detail, with emphasis given to the preparation of thin self-supporting carbon foils used as target backings and stripper foils. Various target backings, and the merits of the more generally used release agents are described in detail. The preparations of more difficult elemental targets are discussed, and a comprehensive list of the common targets is presented

  7. Study of the influence of substrate temperature on structural, optical, and electrical properties of Zn-doped MnIn2S4 thin films prepared by chemical spray pyrolysis

    Science.gov (United States)

    Kennedy, A.; Viswanathan, K.; Pradeev raj, K.

    2016-08-01

    The Zn-doped MnIn2S4 thin films were deposited by chemical spray pyrolysis technique on a heated glass substrate using the aqueous solution of MnCl2, InCl3, (NH2)2CS and ZnCl2. The thin films were grown at different substrate temperatures ranging from 250-400 °C. The synthesized films were characterized by X-ray diffraction (XRD), energy dispersive analysis spectrum (EDS), field emission scanning electron microscope (FESEM), UV-Vis absorption spectroscopy and four probe method. The XRD analysis indicates Zn-doped MnIn2S4 thin films were polycrystalline in nature with a cubic spinel structure having (101) plane as the preferred orientation. The structural parameters like crystalline size (D), dislocation density (δ), strain (ε) and lattice distortion (LD) have been evaluated from XRD results. The energy dispersive analysis spectrum (EDS) predicts the presence of Mn, In, S and Zn in the film grown at 250 °C. The formation of the needle and spherical shaped grains was clearly observed from FE-SEM analysis. From the optical studies, it is analyzed that about (88%) of light transmission occurs in the Vis-IR regions. It is interesting to note that the structural homogeneity and crystallinity of the films has improved due to the decrease in the absorption coefficient (α) and extinction coefficient (K) with an increase in substrate temperature. The calculated optical band gap energies increase (1.51-1.74 eV) with an increase of substrate temperatures. The photoluminescence (PL) spectrum reveals the presence of well-defined band edge (<400 nm) and defect emissions in the wavelength region around 400-650 nm. Moreover, from electrical studies, the electrical resistivity decreases with increase in substrate temperature and a minimum electrical resistivity of 1.20 ×103 Ωm was obtained for the film coated at 400 °C. The high absorption coefficient (α) in the order of 104cm-1 and high transmittance (88%) of the films makes them an efficient absorber and a good window

  8. Study on Preparation and Properties of High Purity MgSe Polycrystalline by Chemical Vapor Synthesizing%高纯MgSe多晶的化学气相合成及特性研究

    Institute of Scientific and Technical Information of China (English)

    李辉斌; 李焕勇; 付泽华; 田世俊

    2013-01-01

    MgSe polycrystalline were grown by chemical vapor transport ( CVT) method, using Mg and Se elements as the raw materials and NH4C1 as the transport agent, respectively. The temperature range for synthesizing samples are from 999 ℃ to 992 ℃. The as-grown MgSe polycrystalline were characterized by XRD, UV-VIS-NIR spectrophotometer, infrared spectrometer and photoluminescence for their structures and optical properties. The results indicate the product is MgSe polycrystalline, which have NaCl structure, the Eg of MgSe polycrystalline is 1.98 eV. Two emission bands were detected around 1.6 eV, which can be attributed to donoracceptor recombination. The results prove that growing MgSe polycrystalline in one step from magnesium and selenium with the assistance of NH4G1 reaction accelerator is a good method.%以高纯Mg、Se单质为原料,NH4Cl作反应促进剂,温度为999~992℃,采用化学气相输运法(CVT)成功合成出MgSe多晶.采用X射线粉末衍射仪、紫外-可见-近红外分光光度计、傅立叶变换红外光谱仪以及光致发光测试系统研究了MgSe多晶的结构和光学特性.结果表明:合成物为MgSe多晶,具有NaCl型结构,禁带宽度Eg为1.98eV,在1.6eV附近内存在与施主-受主对辐射复合发光相关的发光带.研究证明由Mg、Se单质在促进剂NH4Cl辅助下直接合成MgSe多晶是一种较好的方法.

  9. Nanocrystalline CdS{sub 1−x}Se{sub x} alloys as thin films prepared by chemical bath deposition: Effect of x on the structural and optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Ramirez, E.A. [Escuela Superior de Ingeniería Química e Industrias Extractivas, Instituto Politécnico Nacional, CP 07738, México D.F. (Mexico); Hernandez-Perez, M.A., E-mail: mhernandezp0606@ipn.mx [Escuela Superior de Ingeniería Química e Industrias Extractivas, Instituto Politécnico Nacional, CP 07738, México D.F. (Mexico); Aguilar-Hernandez, J. [Escuela Superior de Física y Matemáticas, Instituto Politécnico Nacional, CP 07738, México D.F. (Mexico); Rangel-Salinas, E. [Escuela Superior de Ingeniería Química e Industrias Extractivas, Instituto Politécnico Nacional, CP 07738, México D.F. (Mexico)

    2014-12-05

    Highlights: • CdS1−xSe{sub x} films with tunable structural and optical properties were grown by CBD. • Thin films are composed by a solid solution of the CdS{sub 1−x}Se{sub x} ternary alloy. • Crystal size, band gap and photoluminescence signal, decrease with the composition. • Ternary alloys show hexagonal phase with preferential orientation on (0 0 2) plane. • Films with x ⩾ 0.5 show semi-spherical grains composed by nanoworms structures. - Abstract: CdS{sub 1−x}Se{sub x} thin films were deposited on Corning glass substrates at 75 °C by chemical bath deposition (CBD) varying the composition “x” from 0 to 1 at a constant deposition time of 120 min. The composition of the films was adjusted by modifying the concentration as well as the ratio of the precursors. The morphological, compositional, structural and optical properties of the films were analyzed using several techniques such as Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), X-ray Diffraction (XRD), UV–Vis Spectroscopy (UV–Vis) and Photoluminescence (PL). The films grow as layers following the ion by ion mechanism, the density of the films decreases with x. Films are constituted by clusters (100–600 nm in diameter) of semispherical particles with sizes fluctuating from 10 to 20 nm. For x ⩾ 0.5 the particles are well-arranged in a “worm-like” structure. All the films are polycrystalline, to x = 0 (CdS) the cubic phase is present, the increase of composition promotes the formation of hexagonal phase or a mixture of both cubic and hexagonal phases. Preferential orientation in the (1 0 0) or (0 0 2) plane is observed. The crystal size decreases from 20 to 6 nm when x is increased. The optical properties can be easily tuned by adjusting the composition. Optical absorption analysis shows that the band gap (E{sub g}) value shifts to red in function of x (from 2.47 to 1.99 eV). Photoluminescence signal changes as “x” varies showing a regular behavior

  10. 非泼罗尼纳米乳的制备及理化性质与安全性分析%Preparation and Physical and Chemical Properties and Security Analysis of Fipronil Nanoemulsion

    Institute of Scientific and Technical Information of China (English)

    郭建军; 欧阳五庆; 李会芳; 苏金辉; 马志倩; 李旭召; 张莹

    2013-01-01

    The purpose of this study was to establish Fipronil nanoemulsion formula and to analyse its quality and security.The appropriate oil phase and surfactant were selected according to the drug loading,stability and toxicity of nanoemulsion and the optimum formula was designed using pseudo-ternary phase diagram.The configuration was measured by TEM and the particle size,polydispersity and zeta potential were measured by LPSA.The stability was tested by high speed centrifugation and optic observation.Its security was evaluated in this study by dermal acute toxicity and LD50.Evaluation of its transdermal permeability was measured by utilizing modified Franz diffusion device.The optimum formula of Fipronil nanoemulsion was composed of 1.2% (w/w) Fipronil,8.0% (w/w) cinnamaldehyde,32.0% (w/w) EL-40 and 58.8% (w/w) distilled water.The shape of Fipronil nanoemulsion droplet was spherical under TEM and the particle size ranged from 5 to 24 nm,with the average diameter of 11.5 nm.The PDI was 0.218 and the Zata potential was-20.6 mY.It was stable.The security test demonstrated that its dermal acute toxicity test was good and LD50 was 2 626 mg · kg-1,therefore it was Low-toxic.Its percutaneous penetration was enhanced.The Fipronil nanoemulsion was successfully prepared,it was stable and Low-toxic.Its percutaneous penetration was well.%作者拟制备非泼罗尼纳米乳,并对其理化性质及安全性进行分析.以纳米乳的载药量、稳定性和毒性为考察指标,筛选合适的油相、表面活性剂,再利用伪三元相图选出最佳配方,制备出非泼罗尼纳米乳.用透射电镜观察非泼罗尼纳米乳的形态;用激光粒度分析仪测定其粒径分布范围、多分散系数(PDI)和Zeta电位;通过留样观察和加速试验考察其稳定性;通过皮肤毒性试验和急性毒性试验评估其安全性;通过改良的Franz扩散装置考察其透皮性.结果显示非泼罗尼纳米乳最佳配方:非泼罗尼1.2

  11. Research on Preparation of White Carbon Black from Oil Shale Residue by Chemical Way%化学法处理油页岩渣制备白炭黑的研究

    Institute of Scientific and Technical Information of China (English)

    薛彦辉; 郭婷婷; 薛真

    2012-01-01

    White carbon black was prepared by acid leaching and alkali dissolving using oil shale residue as materials. When acid leaching was conducted,the iron aluminides were dissolved first,then the residue was treated by sodium hydroxide to get white carbon black. On the contrary, when alkali dissolving was conducted, alkali heating went first,dissolving the compounds of silicon dioxide and aluminum,then iron was recovered by acid. The experi-mental result showed that the technology of alkali dissolving is better than that of acid leaching,the leaching rate of acid leaching is 22.1% ,alkali 30.6%. Thus,the optimum technological condition by alkali dissolving was determined; the reaction temperature is 100t ,the reaction time is 4h,the ratio of NaOH to SiO2 is 4. Under this condition, the leaching rate of white carbon black can reach 48.5%. The oil shale residue can be utilized rationally .realizing waste recovery.%以油页岩渣为原料,分别用酸浸法和碱溶法制备了白炭黑.酸浸法主要是先用浓盐酸溶解其中的铁和铝的化合物,然后再用氢氧化钠处理剩下的残渣,得到白炭黑.而碱法与其相反,先用碱煮,将其中主要的二氧化硅和铝的化合物溶解,再用酸回收剩余的铁.试验结果表明酸法处理油页岩渣工艺的白炭黑提取率为22.1%,碱法处理油页岩渣工艺的白炭黑提取率为30.6%,碱法工艺比酸法工艺优越.进一步探讨了碱法处理油页岩渣制备白炭黑工艺的反应温度、反应时间以及碱浓度等对白炭黑提取率的影响,较佳工艺条件为:反应温度100℃、反应时间4.0h、NaOH/SiO2=4,该条件下白炭黑提取率可达48.5%.化学法处理油页岩渣制备白炭黑可使油页岩渣得到充分合理的利用,实现废物资源化.

  12. Rhenium Nanochemistry for Catalyst Preparation

    Directory of Open Access Journals (Sweden)

    Vadim G. Kessler

    2012-08-01

    Full Text Available The review presents synthetic approaches to modern rhenium-based catalysts. Creation of an active center is considered as a process of obtaining a nanoparticle or a molecule, immobilized within a matrix of the substrate. Selective chemical routes to preparation of particles of rhenium alloys, rhenium oxides and the molecules of alkyltrioxorhenium, and their insertion into porous structure of zeolites, ordered mesoporous MCM matrices, anodic mesoporous alumina, and porous transition metal oxides are considered. Structure-property relationships are traced for these catalysts in relation to such processes as alkylation and isomerization, olefin metathesis, selective oxidation of olefins, methanol to formaldehyde conversion, etc.

  13. 黔产毛蒟提取物的制备及其化学成分的定性分析%Analysis of Piper puberulum (Benth.) Maxim.extracts preparation and the preliminary qualitative chemical composition

    Institute of Scientific and Technical Information of China (English)

    杨艳; 吴芹; 龚其海; 徐世兵; 石京山

    2015-01-01

    Objective To investigate optimal extraction process of Piper puberulum ( Benth.) Maxim.and qualitative analyze the chemical component of the extracts.Methods Method of solvent heating reflux was used for extraction.On the basis of single factor experiment, L9 (34 ) orthogonal experiment was designed with the variants of extraction frequency, time, material-liquid ratio, and immersion time.Extraction rate as index, extraction processes were optimized to achieve best extraction.The extracts, including total extract, water elution, and ethanol elution, were physiochemically analysed to achieve an initial qualitative result.Results The optimal extraction process was: extractions 3 times for 2 hours, with an 1︰30 material -liquid ratio and 2 hours of immersion, Initial qualitative analyzed the total extracts containing amino acids, polypeptides, proteins, alkaloids, steroids or triterpenes, flavones, saponins, polysaccharides, reducing sugars or glucosides, cumarins, terpene lactones, phenols, and tannins.The water elution containing: amino acids, polypeptides, proteins, saponins, polysaccharides, reducing sugars or glucosides, cumarins, and terpene lactones.The ethanol elution containing: amino acids, polypeptides, proteins, alkaloids, steroids or triterpenes, flavones, polysaccharides, reducing sugars or glucosides, phenols, and tanins.Conclusion The experiments show that optimal extraction process can achieve high extraction yield, stable and practical.%目的:考察黔产毛蒟提取物制备的最佳工艺,定性分析各提取物的化学成分。方法采用溶剂回流加热法进行提取。在单因素试验的基础上,以提取次数、提取时间、料液比和浸泡时间为因素安排L9(34)正交试验,以提取率为指标,优选黔产毛蒟提取的最佳工艺;经D-101大孔吸附树脂分离,得到黔产毛蒟水洗脱液、醇洗脱液;采用理化分析方法对黔产毛蒟提取物进行初步定性分析。结果提取

  14. Chemical carcinogenesis

    Directory of Open Access Journals (Sweden)

    Paula A. Oliveira

    2007-12-01

    Full Text Available The use of chemical compounds benefits society in a number of ways. Pesticides, for instance, enable foodstuffs to be produced in sufficient quantities to satisfy the needs of millions of people, a condition that has led to an increase in levels of life expectancy. Yet, at times, these benefits are offset by certain disadvantages, notably the toxic side effects of the chemical compounds used. Exposure to these compounds can have varying effects, ranging from instant death to a gradual process of chemical carcinogenesis. There are three stages involved in chemical carcinogenesis. These are defined as initiation, promotion and progression. Each of these stages is characterised by morphological and biochemical modifications and result from genetic and/or epigenetic alterations. These genetic modifications include: mutations in genes that control cell proliferation, cell death and DNA repair - i.e. mutations in proto-oncogenes and tumour suppressing genes. The epigenetic factors, also considered as being non-genetic in character, can also contribute to carcinogenesis via epigenetic mechanisms which silence gene expression. The control of responses to carcinogenesis through the application of several chemical, biochemical and biological techniques facilitates the identification of those basic mechanisms involved in neoplasic development. Experimental assays with laboratory animals, epidemiological studies and quick tests enable the identification of carcinogenic compounds, the dissection of many aspects of carcinogenesis, and the establishment of effective strategies to prevent the cancer which results from exposure to chemicals.A sociedade obtém numerosos benefícios da utilização de compostos químicos. A aplicação dos pesticidas, por exemplo, permitiu obter alimento em quantidade suficiente para satisfazer as necessidades alimentares de milhões de pessoas, condição relacionada com o aumento da esperança de vida. Os benefícios estão, por

  15. Formulation, Preparation, and Characterization of Polyurethane Foams

    Science.gov (United States)

    Pinto, Moises L.

    2010-01-01

    Preparation of laboratory-scale polyurethane foams is described with formulations that are easy to implement in experiments for undergraduate students. Particular attention is given to formulation aspects that are based on the main chemical reactions occurring in polyurethane production. This allows students to develop alternative formulations to…

  16. Preparation of Electrically Conductive Polymeric Membranes

    Science.gov (United States)

    Encinas, J. C.; Castillo-Ortega, M. M.; Rodríguez, F.; Castaño, V. M.

    2015-10-01

    Cellulose acetate porous membranes, coated with polyaniline, were chemically modified with polyelectrolytes to produce films of varying and controlled porosity and electrical conductivity. The highest electrical conductivity was obtained in membranes prepared with poly(styrene sulfonate) with large pore sizes. The electrical properties as well as scanning electron microscopy (SEM) images are discussed.

  17. Chemical cosmology

    CERN Document Server

    Boeyens, Jan CA

    2010-01-01

    The composition of the most remote objects brought into view by the Hubble telescope can no longer be reconciled with the nucleogenesis of standard cosmology and the alternative explanation, in terms of the LAMBDA-Cold-Dark-Matter model, has no recognizable chemical basis. A more rational scheme, based on the chemistry and periodicity of atomic matter, opens up an exciting new interpretation of the cosmos in terms of projective geometry and general relativity. The response of atomic structure to environmental pressure predicts non-Doppler cosmical redshifts and equilibrium nucleogenesis by alp

  18. Zinc Oxide Hydrogen Sulfide Removal Catalyst/ Preparation, Activity Test and Kinetic Study

    OpenAIRE

    Ameel. M. Rahman; Zuhair A-A Khammas; Karim H. Hassan

    2008-01-01

    Hydrogen sulfide removal catalyst was prepared chemically by precipitation of zinc bicarbonate at a controlled pH. The physical and chemical catalyst characterization properties were investigated. The catalyst was tested for its activity in adsorption of H2S using a plant that generates the H2S from naphtha hydrodesulphurization and a unit for the adsorption of H2S. The results comparison between the prepared and commercial catalysts revealed that the chemical method can be used to prepare th...

  19. Chemical spectroscopy

    International Nuclear Information System (INIS)

    The purpose of chemical spectroscopy with neutrons is to utilize the dependence of neutron scattering cross-sections on isotope and on momentum transfer (which probes the spatial extent of the excitation) to understand fundamental and applied aspects of the dynamics of molecules and fluids. Chemical spectroscopy is divided into three energy ranges: vibrational spectroscopy, 25-500 MeV, for which much of the work is done on Be-filter analyzer instruments; low energy spectroscopy, less than 25 MeV; and high resolution spectroscopy, less than 1 MeV, which typically is performed on backscattering spectrometers. Representative examples of measurements of the Q-depenence of vibrational spectra, higher energy resolution as well as extension of the Q-range to lower values at high energy transfers, and provisions of higher sensitivities in vibrational spectroscopy are discussed. High resolution, high sensitivity, and polarization analysis studies in low energy spectroscopy are discussed. Applications of very high resolution spectroscopy are also discussed

  20. THE USE OF CHEMICALS AS FERTILIZERS. AGRICULTURAL CHEMICALS TECHNOLOGY, NUMBER 1.

    Science.gov (United States)

    Ohio State Univ., Columbus. Center for Vocational and Technical Education.

    THE PURPOSE OF THIS GUIDE IS TO ASSIST TEACHERS IN PREPARING POST-SECONDARY STUDENTS FOR AGRICULTURAL CHEMICAL OCCUPATIONS. ONE OF A SERIES OF EIGHT MODULES, IT WAS DEVELOPED BY A NATIONAL TASK FORCE ON THE BASIS OF DATA FROM STATE STUDIES. SUBJECT MATTER AREAS ARE (1) CHEMICAL NUTRITION OF PLANTS, (2) PLANT GROWTH, (3) TERMINOLOGY,…

  1. 29 CFR 1915.33 - Chemical paint and preservative removers.

    Science.gov (United States)

    2010-07-01

    ... or alkalies, employees shall be protected by suitable face shields to prevent chemical burns on the... 29 Labor 7 2010-07-01 2010-07-01 false Chemical paint and preservative removers. 1915.33 Section... Preparation and Preservation § 1915.33 Chemical paint and preservative removers. (a) Employees shall...

  2. Abstracts Book of 3. International Symposium Chemical Forum

    International Nuclear Information System (INIS)

    The 3. International Symposium Chemical Forum has been held in Warsaw from 14 to 16 April 1997. The development in several important chemical branches have been discussed. Among them; analytical methods, chemical preparation of inorganic and organic compounds, chemistry in environment protection, waste treatment and materials recycling. The microsymposium on cosmetic chemistry has been also organised

  3. Chemical intolerance

    DEFF Research Database (Denmark)

    Dantoft, Thomas Meinertz; Andersson, Linus; Nordin, Steven;

    2015-01-01

    are available, the presence of the condition can only be established in accordance to criteria definitions. Numerous modes of action have been suggested to explain CI, with the most commonly discussed theories involving the immune system, central nervous system, olfactory and respiratory systems as well...... chemical sensitivity (MCS). The symptoms reported by CI subjects are manifold, involving symptoms from multiple organs systems. In severe cases of CI, the condition can cause considerable life-style limitations with severe social, occupational and economic consequences. As no diagnostic tools for CI...... or offered health care solutions with limited or no effect, and they experience being met with mistrust and doubt by health care professionals, the social care system and by friends and relatives. Evidence-based treatment options are currently unavailable, however, a person-centered care model based...

  4. Chemical sensors for nuclear industry

    International Nuclear Information System (INIS)

    Development of chemical sensors for detection of gases at trace levels for applications in nuclear industry will be highlighted. The sensors have to be highly sensitive, reliable and rugged with long term stability to operate in harsh industrial environment. Semiconductor and solid electrolyte based electrochemical sensors satisfy the requirements. Physico-chemical aspects underlying the development of H2 sensors in sodium and in cover gas circuit of the Fast breeder reactors for its smooth functioning, NH3 and H2S sensors for use in Heavy water production industries and NOx sensors for spent fuel reprocessing plants will be presented. Development of oxygen sensors to monitor the oxygen level in the reactor containments and sodium sensors for detection of sodium leakages will also be discussed. The talk will focus the general aspects of identification of the sensing material for the respective analyte species, development of suitable chemical route for preparing them as fine powders, the need for configuring them in thick film or thin film geometries and their performance. Pulsed laser deposition method, an elegant technique to prepare the high quality thin films of multicomponent oxides is demonstrated for preparation of nanostructured thin films of complex oxides and its use in tailoring the morphology of the complex sensing material in the desired form by optimizing the in-situ growth conditions. (author)

  5. International perspectives on coal preparation

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-31

    The report consists of the vugraphs from the presentations which covered the following topics: Summaries of the US Department of Energy`s coal preparation research programs; Preparation trends in Russia; South African coal preparation developments; Trends in hard coal preparation in Germany; Application of coal preparation technology to oil sands extraction; Developments in coal preparation in China; and Coal preparation in Australia.

  6. Preparations, characterizations and applications of chitosan-based nanoparticles

    Science.gov (United States)

    Liu, Chenguang; Tan, Yulong; Liu, Chengsheng; Chen, Xiguang; Yu, Lejun

    2007-07-01

    Chitosan is a natural polysaccharide prepared by the N-deacetylation of chitin. In this paper we have reviewed the methods of preparation of chitosan-based nanoparticles and their pharmaceutical applications. There are five methods of their preparations: emulsion cross-linking, emulsion-droplet coalescence, ionic gelation, reverse micellar method and chemically modified chitosan method. Chitosan nanoparticles are used as carriers for low molecular weight drug, vaccines and DNA. Releasing characteristics, biodistribution and applications are also summarized.

  7. Preparations, Characterizations and Applications of Chitosan-based Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Chitosan is a natural polysaccharide prepared by the N-deacetylation of chitin. In this paper we have reviewed the methods of preparation of chitosan-based nanoparticles and their pharmaceutical applications. There are five methods of their preparations: emulsion cross-linking, emulsion-droplet coalescence, ionic gelation, reverse micellar method and chemically modified chitosan method. Chitosan nanoparticles are used as carriers for low molecular weight drug, vaccines and DNA. Releasing characteristics, biodistribution and applications are also summarized.

  8. Composição físico-química e qualidade do café submetido a dois tipos de torração e com diferentes formas de processamento Physical-chemical composition and quality of coffee submitted to two roasting procedures and to different methods of preparation

    Directory of Open Access Journals (Sweden)

    Heloisa Helena de Siqueira

    2006-02-01

    Full Text Available Este estudo foi desenvolvido com o objetivo de determinar as alterações na composição físico-química, química e sensorial de café cultivar Rubi, o qual foi submetido a diferentes formas de processamento e dois tipos de torração. Foram colhidos cafés de uma lavoura da UFLA com experimento de pivô central. Após o beneficiamento, as amostras foram divididas em cafés crus e torrados, sendo realizadas as seguintes análises: pH, acidez titulável total, cafeína, ácido clorogênico, polifenóis e índice de coloração. Foi realizada também análise sensorial (prova de xícara para determinação da qualidade da bebida. Para a variável polifenol, não houve diferença significativa entre as formas de processamento, sendo que a torração clara apresentou maior teor de polifenol. O café natural apresentou um maior valor de cafeína dentro do tipo de processamento, e dentro do tipo de grão, o grão cru apresentou um maior valor de cafeína. Para a variável índice de coloração, os processamentos despolpado e descascado apresentaram os maiores valores e a torração média também apresentou um maior valor. O processamento natural apresentou um maior teor de ácido clorogênico e para o tipo de grão, a torração média também apresentou um maior valor de ácido clorogênico. Para a variável pH, não houve diferença significativa entre as formas de processamento, e dentro do tipo de grão, o grão cru apresentou um maior valor de pH. Com relação à acidez, o café natural apresentou um maior valor desta variável, e a torração média também apresentou um maior valor. Não houve diferença entre as formas de processamento e tipo de torração em relação à análise sensorial, visto que, todos os cafés foram classificados como bebida dura.This study was carried out to determine alterations in the physical-chemical, chemical and sensorial composition of a Rubi cultivar coffee, which was submitted to different methods of

  9. Chemical simulation of greywater.

    Science.gov (United States)

    Abed, Suhail Najem; Scholz, Miklas

    2016-01-01

    Sustainable water resources management attracts considerable attention in today's world. Recycling and reuse of both wastewater and greywater are becoming more attractive. The strategy is to protect ecosystem services by balancing the withdrawal of water and the disposal of wastewater. In the present study, a timely and novel synthetic greywater composition has been proposed with respect to the composition of heavy metals, nutrients and organic matter. The change in water quality of the synthetic greywater due to increasing storage time was monitored to evaluate the stability of the proposed chemical formula. The new greywater is prepared artificially using analytical-grade chemicals to simulate either low (LC) or high (HC) pollutant concentrations. The characteristics of the synthetic greywater were tested (just before starting the experiment, after two days and a week of storage under real weather conditions) and compared to those reported for real greywater. Test results for both synthetic greywater types showed great similarities with the physiochemical properties of published findings concerning real greywater. Furthermore, the synthetic greywater is relatively stable in terms of its characteristics for different storage periods. However, there was a significant (p change was also noted for the reduction (70%) of nitrate-nitrogen (NO3-N) concerning HC greywater after seven days of storage. PMID:26745659

  10. 21 CFR 1308.24 - Exempt chemical preparations.

    Science.gov (United States)

    2010-04-01

    ... packaged in a sealed, oxygen-free environment, under nitrogen pressure, safeguarded against exposure to the... citations affecting § 1308.24, see the List of CFR Sections Affected, which appears in the Finding Aids section of the printed volume and on GPO Access. Excluded Veterinary Anabolic Steroid Implant Products...

  11. Preparation of ultrafine nickel powder by wet chemical process

    Institute of Scientific and Technical Information of China (English)

    CHEN Rui-ying; ZHOU Kang-gen

    2006-01-01

    The main technical problems of nickel powder for multiplayer ceramic capacitors are particle size controlling, the agglomeration and tap density. Ultrafine nickel powders with submicron size and spherical shape were synthesized by the hydrazine reduction of nickel sulfate in ethanol-water solvent. The effects of reaction temperature, nucleator and flow rate of nickel sulfate solution on nickel powders properties were investigated. The nickel particles synthesized were characterized by SEM and TGA. The results show that the average particle size changes from 0.1 to 0.7 μm by adjusting reaction temperature (53-73 ℃) and flow rate of nickel sulfate solution (50-100 mL/min). Moreover, temperature below 60 ℃ and appropriate flow rate of nickel sulfate solution (85 mL/min) are in favor of obtaining particles with high tap density (>3.0 g/cm3). In addition, the introduction of nucleator is useful to obtaining particles with narrow size distribution.

  12. Preparation and characterization of calcium aluminate by chemical synthesis

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Saturated Ca(OH)2 and AlCl3 solutions were used to synthesize calcium aluminate hydrate precipitates at room temperature; high purity calcium aluminate powders with stable phases were made by calcination of the precursors at a temperature as low as1100℃. PSD and BET analysis revealed the particles with sizes ranging from submicrometer to several micrometers and with a specific area of 13 m2/g. The measurement of hydraulic exotherm revealed that the exothermal rate is in peak for about 2 h. The exothermal quantities are 449.24 J/g at 12 h and 488.38 J/g at 24 h. Its strength development is quick and the 1 day curing strength is almost equal to 100% of the 3 days curing strength in the mortar test.

  13. Clinical and chemical interactions between iron preparations and ciprofloxacin.

    OpenAIRE

    Kara, M; Hasinoff, B B; McKay, D. W.; Campbell, N R

    1991-01-01

    1. The effect of ferrous sulphate (300 mg), ferrous gluconate (600 mg), and a combination tablet of iron (10 mg), magnesium (100 mg), zinc (15 mg), calcium (162 mg), copper (2 mg), and manganese (5 mg) (Centrum Forte) co-administration on ciprofloxacin bioavailability was tested in eight healthy subjects. 2. Peak serum ciprofloxacin concentrations and area under the curve (AUC) were significantly reduced when ciprofloxacin was administered with 300 mg ferrous sulphate (3.0 vs 2.0 mg l-1, P le...

  14. A roadmap to high quality chemically prepared graphene

    NARCIS (Netherlands)

    Gengler, Regis Y. N.; Spyrou, Konstantinos; Rudolf, Petra

    2010-01-01

    Graphene was discovered half a decade ago and proved the existence of a two-dimensional system which becomes stable as a result of 3D corrugation. It appeared very quickly that this exceptional material had truly outstanding electronic, mechanical, thermal and optical properties. Consequently a broa

  15. Aluminium nitride coatings preparation using a chemical vapour deposition process

    Energy Technology Data Exchange (ETDEWEB)

    Armas, B.; Combescure, C.; Icaza Herrera, M. de; Sibieude, F. [Centre National de la Recherche Scientifique (CNRS), 66 - Font-Romeu (France). Inst. de Science et du Genie des Materiaux et des Procedes

    2000-07-01

    Aluminium nitride was obtained in a cold wall reactor using AlCl{sub 3} and NH{sub 3} as precursors and N{sub 2} as a carrier gas. AlCl{sub 3} was synthesized << in situ >> by means of an original method based on the reaction of SiCl{sub 4(g)} with Al{sub (S)}. The substrate used was a cylinder of graphite coated with SiC and heated by high frequency induction. The deposition rate was studied as a function of temperature in the range 900 - 1500 C, the total pressure varying from 2 to 180 hPa. At low temperatures an Arrhenius type representation of the kinetics for several pressures indicated a thermally activated process with an apparent activation energy of about 80 kJ.mol{sup -1}. At high deposition temperatures, the deposition rate was almost constant, indicating that the growth was controlled by a diffusion process. The influence of gas composition and total AlCl{sub 3} flow rate was also discussed. The different layers were characterised particularly by means of X-ray diffraction and SEM. The influence of temperature and total pressure on crystallization and morphology was studied. (orig.)

  16. Chemical information science coverage in Chemical Abstracts.

    Science.gov (United States)

    Wiggins, G

    1987-02-01

    For many years Chemical Abstracts has included in its coverage publications on chemical documentation or chemical information science. Although the bulk of those publications can be found in section 20 of Chemical Abstracts, many relevant articles were found scattered among 39 other sections of CA in 1984-1985. In addition to the scattering of references in CA, the comprehensiveness of Chemical Abstracts as a secondary source for chemical information science is called into question. Data are provided on the journals that contributed the most references on chemical information science and on the languages of publication of relevant articles.

  17. Chemical Engineering in Space

    Science.gov (United States)

    Lobmeyer, Dennis A.; Meneghelli, Barry; Steinrock, Todd (Technical Monitor)

    2001-01-01

    sources is paramount to success. We are currently working on several processes to produce the propellants that would allow us to visit and explore the surface of Mars. The capabilities currently at our disposal for launching and delivering equipment to another planet or satellite dictate that the size and scale of any hardware must be extremely small. The miniaturization of the processes needed to prepare the in situ propellants and life support commodities is a real challenge. Chemical engineers are faced with the prospect of reproducing an entire production facility in miniature so the complex can be lifted into space and delivered to our destination. Another area that does not normally concern chemical engineers is the extreme physical aspects payloads are subjected to with the launch of a spacecraft. Extreme accelerations followed by the sudden loss of nearly all gravitational forces are well outside normal equipment design conditions. If the equipment cannot survive the overall trip, then it obviously will not be able to yield the needed products upon arrival. These launch constraints must be taken into account. Finally, we must consider both the effectiveness and efficiencies of the processes. A facility located on the Moon or Mars will not have an unlimited supply of power or other ancillary utilities. For a Mars expedition, the available electric power is severely limited. The design of both the processes and the equipment must be considered. With these constraints in mind, only the most efficient designs will be viable. Cryogenics, in situ resource utilization, miniaturization, launchability, and power/process efficiencies are only a few of the areas that chemical engineers provide support and expertise for the exploration of space.

  18. Materials Preparation Center

    Data.gov (United States)

    Federal Laboratory Consortium — MPC is recognized throughout the worldwide research community for its unique capabilities in purification, preparation, and characterization of: rare earth metals,...

  19. Preparation of atomic oxygen resistant polymeric materials

    Science.gov (United States)

    Tortorelli, Victor J.; Hergenrother, P. M.; Connell, J. W.

    1991-01-01

    Polyphenyl quinoxalines (PPQs) are an important family of high performance polymers that offer good chemical and thermal stability coupled with excellent mechanical properties. These aromatic heterocyclic polymers are potentially useful as films, coatings, adhesives, and composite materials that demand stability in harsh environments. Our approach was to prepare PPQs with pendent siloxane groups using the appropriate chemistry and then evaluate these polymers before and after exposure to simulated atomic oxygen. Either monomer, the bis(o-diamine)s or the bis(alpha-diketone)s can be synthesized with a hydroxy group to which the siloxane chain will be attached. Several novel materials were prepared.

  20. Controllable preparation of particles with microfluidics

    Institute of Scientific and Technical Information of China (English)

    Guangsheng Luo; Le Du; Yujun Wang; Yangcheng Lu; Jianhong Xu

    2011-01-01

    This paper reviews recent development and achievements in controllable preparation of nanoparticles,micron spherical and non-spherical particles,using microfluidics.A variety of synthesis strategies are presented and compared,including single-phase and multiphase microflows.The main structures of microfluidic devices and the fundamental principles of microflows for particle preparation are summarized and identified.The controllability of particle size,size distribution,crystal structure,morphology,physical and chemical properties,is examined in terms of the special features of microfluidic reactors.An outlook on opinions and predictions concerning the future development of powder technology with microfluidics is specially provided.

  1. Preparation of silver powder through glycerol process

    Indian Academy of Sciences (India)

    Amit Sinha; B P Sharma

    2005-06-01

    High purity fine silver powder with uniform particle morphology was prepared through glycerol process. The process involves reduction of silver nitrate by glycerol under atmospheric conditions at a temperature below 175°C. Glycerol, in this process, acts as a solvent as well as a reducing agent. The powders prepared through this process were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and chemical analysis. The powders were well crystalline and contained oxygen, carbon and hydrogen as impurities. Overall purity was better than 99.9%. The yield of silver powder was better than 99%.

  2. Teaching and Learning in Chemical Product Engineering - an Evolving par of the Chemical Engineering Curriculum

    DEFF Research Database (Denmark)

    Vigild, Martin Etchells; Kiil, Søren; Wesselingh, Johannes

    2007-01-01

    and preparing a text book on the subject. [1] Chemical Product Engineering is solidly based on chemical technical and engineering knowledge. Furthermore, the subject naturally calls for a holistic approach to teaching and learning and introduces elements which target transferable and professional engineering...... the individual to become more assertive and understanding of personal assets. These teaching elements included in Chemical Product Engineering represent a series of general issues in Chemical Engineering Education, which must be discussed as the education is going to adapt to the changes of the surrounding world......Over the last decade Chemical Product Engineering has evolved as part of the Chemical Engineering Curriculum at several universities in Europe and America. At the DTU Chemical Product Engineering was introduced in 2000. This presentation will report on the experiences gained from teaching classes...

  3. 胶溶法制备具有自清洁与抗菌性能的TiO2薄膜%Preparation of TiO2 Thin Films with Self-cleaning and Antibacterial Properties by Colloidal Chemical Method

    Institute of Scientific and Technical Information of China (English)

    樊新民; 洪洋; 汪洋

    2013-01-01

    The anatase sol was synthesized by colloidal chemical method and the nanocrystalline TiO2 films were then prepared on glass substrates by the dip-coating method from the anatase sol. XRD,TEM, SEM, AFM and water contact angle were used to characterize the microstructure of TiO2 sol and films. The results showed that the TiO2 sol was anatase with high crystallinity. The TiO2 crystals were needle like and average crystallite size was about 8 nm. The surface of TiO2 flims were smooth and diameter of particles was 86 nm in average. The thickness of three-layer film is approximately ISO nm. Moreover, coating layers had little influence on morphology. The degradation of methylene blue reached 93. 6% when the films prepared at ambient temperature were irradiated by UV light for 80 min, and the photocatalytic activity increased as heat treatment temperature raised. The TiO2 films possessed self-cleaning and antibacterial properties, as well as super hydrophilicity.%采用胶溶法合成了纳米晶锐钛矿溶胶,在玻璃基底上用提拉法制备出TiO2纳米薄膜.使用XRD、TEM、SEM和AFM和接触角等方法对TiO2溶胶和薄膜的结构进行了表征.结果表明,胶溶法合成的TiO2溶胶为锐钛矿型且结晶度较高,TiO2晶粒为针状,平均粒径约为8 nm;TiO2薄膜表面光滑,颗粒平均粒径约为86 nm.3层薄膜的厚度约为150 nm,涂膜层数对膜表面结构形貌影响有限.常温制备出的薄膜经紫外光照80 min,对亚甲基蓝的降解率达到93.6%,其活性随着热处理温度升高而提高.薄膜具备超亲水性,自清洁和抗菌性能.

  4. Janus nanoparticles: preparation, characterization, and applications.

    Science.gov (United States)

    Song, Yang; Chen, Shaowei

    2014-02-01

    In chemical functionalization of colloidal particles, the functional moieties are generally distributed rather homogeneously on the particle surface. Recently, a variety of synthetic protocols have been developed in which particle functionalization may be carried out in a spatially controlled fashion, leading to the production of structurally asymmetrical particles. Janus particles represent the first example in which the two hemispheres exhibit distinctly different chemical and physical properties, which is analogous to the dual-faced Roman god, Janus. Whereas a variety of methods have been reported for the preparation of (sub)micron-sized polymeric Janus particles, it has remained challenging for the synthesis and (unambiguous) structural characterization of much smaller nanometer-sized Janus particles. Herein, several leading methods for the preparation of nanometer-sized Janus particles are discussed and the important properties and applications of these Janus nanoparticles in electrochemistry, sensing, and catalysis are highlighted. Some perspectives on research into functional patchy nanoparticles are also given. PMID:24376180

  5. PREPARATIVE SKIN PREPARATION AND SURGICAL WOUND INFECTION

    OpenAIRE

    Anjanappa; Arjun

    2015-01-01

    BACKGROUND AND OBJECTIVE: It is an established fact now that the normal skin of healthy human beings harbours a rich bacterial fl ora. Normally considered non - pathogenic , these organisms way be a potential source of infection of the surgical wound. Approximately 20% of the resident flora is beyond the reach of surgical scrubs and antiseptics. The goal of surgical preparation of the skin with antiseptics is to remove transient and pathogenic microorganism...

  6. Preparation of double-walled carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    JIANG Bin; WEI Jinquan; CI Lijie; WU Dehai

    2004-01-01

    Double-walled carbon nanotubes were prepared using the floating chemical vapor deposition with methane as carbon source and adding small amount of sulfur into the ferrocene catalyst. The optimized technological parameters are: the reaction temperature is 1200℃; the catalyst vapor temperature is 80℃; the flow rate of argon is 2000 SCCM; the flow rate of methane is 5 SCCM. The purified DWNTs under these optimized technological parameters have high purity above 90 wt%.

  7. Cluster model of chemical modification of sapropelitic coals

    Energy Technology Data Exchange (ETDEWEB)

    Bodoev, N.V.; Kozlov, A.P.; Gruber, R.; Kucherenko, V.A.; Guet, J.-M. [Buryat State University, Ulan-Ude (Russian Federation)

    1999-07-01

    The possibility of active carbon preparation from sapropelitic coals was investigated. Chemical modification and structural alteration as well as thermolysis of modified sapropelite are described. 2 refs., 2 tabs.

  8. PREPARATIVE SKIN PREPARATION AND SURGICAL WOUND INFECTION

    Directory of Open Access Journals (Sweden)

    Anjanappa

    2015-01-01

    Full Text Available BACKGROUND AND OBJECTIVE: It is an established fact now that the normal skin of healthy human beings harbours a rich bacterial fl ora. Normally considered non - pathogenic , these organisms way be a potential source of infection of the surgical wound. Approximately 20% of the resident flora is beyond the reach of surgical scrubs and antiseptics. The goal of surgical preparation of the skin with antiseptics is to remove transient and pathogenic microorganisms on the skin surface and to reduce the resident flora to a low level. Povidone iodine (I odophors and chlorhexidine are most often used antiseptics for pre - operative skin preparation. OBJECTIVES : To evaluate the efficacy of povidone iodine alone and in combination with antiseptic agent containing alcoholic chlorhexidine in preoperative skin p reparation by taking swab culture. (2 To compare the rate of postoperative wound infection in both the groups. METHODS: One hundred patients (fifty in each group undergoing clean elective surgery with no focus of infection on the body were included in th e study. The pre - operative skin preparation in each group is done with the respective antiseptic regimen. In both the groups after application of antiseptics , sterile saline swab culture was taken immediately from site of incision. In cases which showed gr owth of organisms , the bacteria isolated were identified by their morphological and cultural characteristics. Grams staining , coagulase test and antibiotic sensitivity test were done wherever necessary and difference in colonization rates was determined as a measure of efficacy of antiseptic regimen. RESULTS: The results of the study showed that when compared to povidone iodine alone , using a combination of povidone iodine and alcoholic solution of chlorhexidine , the colonization rates of the site of incisi on were reduced significantly. As for the rate of post - operative wound infection , it is also proven that wound infections are also

  9. An X-band Co{sup 2+} EPR study of Zn{sub 1−x}Co{sub x}O (x=0.005–0.1) nanoparticles prepared by chemical hydrolysis methods using diethylene glycol and denaturated alcohol at 5 K

    Energy Technology Data Exchange (ETDEWEB)

    Misra, Sushil K., E-mail: skmisra@alcor.concordia.ca [Physics Department, Concordia University, Montreal, QC, Canada H3G 1M8 (Canada); Andronenko, S.I. [Physics Institute, Kazan Federal University, Kazan 420008 (Russian Federation); Srinivasa Rao, S.; Chess, Jordan; Punnoose, A. [Department of Physics, Boise State University, Boise, ID 83725-1570 (United States)

    2015-11-15

    EPR investigations on two types of dilute magnetic semiconductor (DMS) ZnO nanoparticles doped with 0.5–10% Co{sup 2+} ions, prepared by two chemical hydrolysis methods, using: (i) diethylene glycol ((CH{sub 2}CH{sub 2}OH){sub 2}O) (NC-rod-like samples), and (ii) denatured ethanol (CH{sub 3}CH{sub 2}OH) solutions (QC-spherical samples), were carried out at X-band (9.5 GHz) at 5 K. The analysis of EPR data for NC samples revealed the presence of several types of EPR lines: (i) two types, intense and weak, of high-spin Co{sup 2+} ions in the samples with Co concentration >0.5%; (ii) surface oxygen vacancies, and (iii) a ferromagnetic resonance (FMR) line. QC samples exhibit an intense FMR line and an EPR line due to high-spin Co{sup 2+} ions. FMR line is more intense, than the corresponding line exhibited by NC samples. These EPR spectra varied for sample with different doping concentrations. The magnetic states of these samples as revealed by EPR spectra, as well as the origin of ferromagnetism DMS samples are discussed. - Highlights: • 5 K X band Co{sup 2+} EPR investigations on QC and NC ZnO dilute magnetic semiconductor nanoparticles. • NC and QC samples exhibited high-spin Co{sup 2+} EPR lines and ferromagnetic resonance line. • NC sample also exhibit line due surface oxygen vacancies. • FMR line is more intense in QC than that in NC samples. • Magnetic states and the origin of ferromagnetism are discussed.

  10. 应用镁金属化学还原法制备多孔 Si/Si-O-C 负极材料机理研究%Mechanism of porous Si/Si-O-C anode material prepared by chemical reduction with magnesium

    Institute of Scientific and Technical Information of China (English)

    郑春满; 刘相; 谢凯; 韩喻

    2016-01-01

    以二乙烯基苯和聚硅氧烷为原料经先驱体转化法制备 Si-O-C 材料,利用镁金属在惰性气氛保护下高温还原制备多孔的 Si /Si-O-C 负极材料。利用 X 射线衍射、能谱分析、元素分析和场发射扫描电镜分析多孔 Si /Si-O-C 负极材料的组成、结构、形貌,从而研究利用镁金属化学还原法制备多孔 Si /Si-O-C 负极材料的机理。结果表明,镁金属在还原过程中生成 MgO 和 Mg2 SiO4等产物,经 HCl 洗涤后可形成多孔的 Si /Si-O-C 负极材料。Si /Si-O-C 材料中的单质硅分布于多孔的 Si-O-C 相中,一定程度上可缓解 Si 在循环过程中产生的体积效应。利用镁金属还原 Si-O-C 材料制备多孔 Si /Si-O-C 材料是一种可行的制备方法。%Si-O-C material was prepared by a polymer-derived method using copolymer of phenyl-substituted polysiloxane and divinylbenzene as raw materials.The porous Si /Si-O-C anode material was prepared with the chemical reduction of Si-O-C material by magnesium at high temperature under argon atmosphere.The composition,structure,morphology,and formation process of porous Si /Si-O-C anode material were investigated by X-ray diffraction, energy spectrum analysis, elemental analysis and field emission scanning electron microscope. The electrochemical properties of the material were characterized by using the electrochemical test instrument.The research results show that the magnesium will react with oxygen of Si-O-C material and turn into MgO and Mg2 SiO4 during the reduction process.When washed with HCl,MgO and Mg2 SiO4 react with HCl and turn into MgCl2 ,which can dissolve in the solution.Then,the porous Si /Si-O-C anode materials are formed.The silicon distribute in the porous Si-O-C material,which can improve the cycle performance of silicon.It can confirms that the material prepared by using magnesium reduction method is a potential material for the lithium-ion battery.

  11. Effect of preparation conditions on physicochemical, surface and catalytic properties of cobalt ferrite prepared by coprecipitation

    Energy Technology Data Exchange (ETDEWEB)

    El-Shobaky, G.A., E-mail: elshobaky@yahoo.co [Physical Chemistry Department, National Research Center, Dokki, Cairo (Egypt); Turky, A.M.; Mostafa, N.Y.; Mohamed, S.K. [Chemistry Department, Faculty of Science, Suez Canal University, Ismailia 41522 (Egypt)

    2010-03-18

    Cobalt ferrite nanoparticles were prepared via thermal treatment of cobalt-iron mixed hydroxides at 400-600 {sup o}C. The mixed hydroxides were coprecipitated from their nitrates solutions using NaOH as precipitating agent. The effects of pH and temperature of coprecipitation and calcination temperature on the physicochemical, surface and catalytic properties of the prepared ferrites were studied. The prepared systems were characterized using TG, DTG, DTA, chemical analysis, atomic absorption spectroscopy (AAS), X-ray diffraction (XRD), energy dispersive X-ray (EDX) as well as surface and texture properties based on nitrogen adsorption-desorption isotherms. The prepared cobalt ferrites were found to be mesoporous materials that have crystallite size ranges between 8 and 45 nm. The surface and catalytic properties of the produced ferrite phase were strongly dependent on coprecipitation conditions of the mixed hydroxides and on their calcination temperature.

  12. Conceptests for a Chemical Engineering Thermodynamics Course

    Science.gov (United States)

    Falconer, John L.

    2007-01-01

    Examples of conceptests and suggestions for preparing them for use in an undergraduate, chemical engineering thermodynamics course are presented. Conceptests, combined with hand-held transmitters (clickers), is an effective method to engage students in class. This method motivates students, improves their functional understanding of…

  13. Microfluidic chemical reaction circuits

    Science.gov (United States)

    Lee, Chung-cheng; Sui, Guodong; Elizarov, Arkadij; Kolb, Hartmuth C.; Huang, Jiang; Heath, James R.; Phelps, Michael E.; Quake, Stephen R.; Tseng, Hsian-rong; Wyatt, Paul; Daridon, Antoine

    2012-06-26

    New microfluidic devices, useful for carrying out chemical reactions, are provided. The devices are adapted for on-chip solvent exchange, chemical processes requiring multiple chemical reactions, and rapid concentration of reagents.

  14. Thyroid preparation overdose

    Science.gov (United States)

    Thyroid preparations are medicines used to treat thyroid gland disorders. Overdose occurs when someone takes more than the normal or recommended amount of this medicine. This can be by accident or ...

  15. Chemical Security Analysis Center

    Data.gov (United States)

    Federal Laboratory Consortium — In 2006, by Presidential Directive, DHS established the Chemical Security Analysis Center (CSAC) to identify and assess chemical threats and vulnerabilities in the...

  16. Preparation and Analysis of Biomass Lignins

    Science.gov (United States)

    Compere, Alicia L.; Griffith, William L.

    Lignin, comprised primarily of three randomly polymerized phenylpropenyl monomers, is, arguably, the second most common organic molecule on earth. In current biorefinery applications, lignin is burned, usually in concentrated pulping or hydrolysis liquor, as a source of process steam and both internal and exported electricity. The aromatic content of lignin makes it a potentially attractive feedstock for high-value aromatic chemicals, polymers, and carbon products (graphite, activated carbon, and carbon fiber). Revenue from production of lignin-based chemicals could play a major role in biorefinery profitability if cost-effective methods for lignin separation and purification can be developed. This chapter presents descriptions of methods for assessing and purifying biorefinery lignins so that they can be evaluated for use as feedstock for production of chemical products. Areas covered are: (1) initial evaluations of as-received lignin samples (visual, microscopic, separable organics); (2) analysis of common contaminants (bulk and filterable ash and particulate contaminants in liquid and dry lignin samples); (3) preparation of lignins for experimental use as chemical feedstock (prefiltration, filtration using bench-scale chemical apparatus and larger scale bag filters, one-step lignin precipitation, two-step carbohydrate and lignin precipitation, desalting of dry powdered or precipitated lignin, and lyophilization). These methods have been used successfully at the bench scale to produce the 1-50 kg amounts of wood and grass lignins typically required for bench-scale assessment as chemical feedstocks.

  17. Preparation and integration of nanostructured titanium dioxide

    KAUST Repository

    Zeng, Hua Chun

    2011-10-01

    Titanium dioxide (TiO2) is a chemically stable nontoxic transition-metal oxide associated with a wide range of existing chemical engineering processes. In this short review, recent research endeavors in preparation and integration of nanostructured TiO2 materials system will be featured and discussed for their potential new applications. Because material development always plays pivotal roles in the progress of a particular engineering discipline, the reviewed subjects will provide useful information to stimulate nanoscale research of chemical engineering, linking established fundamentals with practical applications. Some critical issues and challenges regarding further development of this important functional material for nanotechnology will also be addressed. © 2011 Elsevier Ltd. All rights reserved.

  18. Physico-chemical Properties of Marine Phospholipid Emulsions

    DEFF Research Database (Denmark)

    Lu, Henna Fung Sieng; Nielsen, Nina Skall; Baron, Caroline P.;

    2012-01-01

    of this study was to investigate the emulsifying properties of various commercial marine PL and the feasibility of using them to prepare stable emulsions prepared with or without addition of fish oil. In addition, this study also investigated the relationship between chemical composition of marine PL...

  19. Predicting Anatomical Therapeutic Chemical (ATC classification of drugs by integrating chemical-chemical interactions and similarities.

    Directory of Open Access Journals (Sweden)

    Lei Chen

    Full Text Available The Anatomical Therapeutic Chemical (ATC classification system, recommended by the World Health Organization, categories drugs into different classes according to their therapeutic and chemical characteristics. For a set of query compounds, how can we identify which ATC-class (or classes they belong to? It is an important and challenging problem because the information thus obtained would be quite useful for drug development and utilization. By hybridizing the informations of chemical-chemical interactions and chemical-chemical similarities, a novel method was developed for such purpose. It was observed by the jackknife test on a benchmark dataset of 3,883 drug compounds that the overall success rate achieved by the prediction method was about 73% in identifying the drugs among the following 14 main ATC-classes: (1 alimentary tract and metabolism; (2 blood and blood forming organs; (3 cardiovascular system; (4 dermatologicals; (5 genitourinary system and sex hormones; (6 systemic hormonal preparations, excluding sex hormones and insulins; (7 anti-infectives for systemic use; (8 antineoplastic and immunomodulating agents; (9 musculoskeletal system; (10 nervous system; (11 antiparasitic products, insecticides and repellents; (12 respiratory system; (13 sensory organs; (14 various. Such a success rate is substantially higher than 7% by the random guess. It has not escaped our notice that the current method can be straightforwardly extended to identify the drugs for their 2(nd-level, 3(rd-level, 4(th-level, and 5(th-level ATC-classifications once the statistically significant benchmark data are available for these lower levels.

  20. Reference field effect transistor based on chemically modified ISFETs

    NARCIS (Netherlands)

    Skowronska-Ptasinska, Maria; Wal, van der Peter D.; Berg, van den Albert; Bergveld, Piet; Sudhölter, Ernst J.R.; Reinhoudt, David N.

    1990-01-01

    Different hydrophobic polymers were used for chemical modification of ion-sensitive field effect transistors (ISFETs) in order to prepare a reference FET (REFET). Chemical attachment of the polymer to the ISFET gate results in a long lifetime of the device. Properties of polyacrylate (polyACE) REFET

  1. Mass and Heat Transfer Enhancement of Chemical Heat Pumps

    Institute of Scientific and Technical Information of China (English)

    Gui-PingLin; Xiu-GanYuan

    1993-01-01

    An inert additive,expanded graphit(EG),has been prepared and used to enhance the heat and mass transfer process of chemical heat pumps.The effects of mixing ratio and mixing method on the chemical reaction time are investigated.

  2. Method for fractional solid-waste sampling and chemical analysis

    DEFF Research Database (Denmark)

    Riber, Christian; Rodushkin, I.; Spliid, Henrik;

    2007-01-01

    Chemical characterization of solid waste is a demanding task due to the heterogeneity of the waste. This article describes how 45 material fractions hand-sorted from Danish household waste were subsampled and prepared for chemical analysis of 61 substances. All material fractions were subject...

  3. Influences of sample preparations on dentine ESR signals

    International Nuclear Information System (INIS)

    The work is to study influences of sample preparations on dentine ESR (electron spin resonance) signals, in order to use dentine samples for dose reconstruction, which has been performed with enamel samples. The dentine and enamel samples were collected from non-irradiated adult teeth and prepared by mechanical or mechanical plus chemical methods. The samples were scanned by an ESR spectrometer before and after their irradiation by 60Co γ-rays. The sensitivities of ESR signals of dentine and enamel samples to irradiation dose differed significantly among different sample preparation methods. The results show that dentine samples mechanically and chemically prepared have good enough ESR response to low dose γ-ray irradiations, and it is possible to use the dentine samples for dose reconstruction, as a substitution to enamel samples when they are short of supply. (authors)

  4. The chemical life(1).

    Science.gov (United States)

    Hodges, Nathan

    2015-01-01

    You write this narrative autoethnography to open up a conversation about our chemical lives. You go through your day with chemical mindfulness, questioning taken-for-granted ideas about natural and artificial, healthy and unhealthy, dependency and addiction, trying to understand the chemical messages we consume through the experiences of everyday life. You reflect on how messages about chemicals influence and structure our lives and why some chemicals are celebrated and some are condemned. Using a second-person narrative voice, you show how the personal is relational and the chemical is cultural. You write because you seek a connection, a chemical bond. PMID:24905820

  5. The chemical life(1).

    Science.gov (United States)

    Hodges, Nathan

    2015-01-01

    You write this narrative autoethnography to open up a conversation about our chemical lives. You go through your day with chemical mindfulness, questioning taken-for-granted ideas about natural and artificial, healthy and unhealthy, dependency and addiction, trying to understand the chemical messages we consume through the experiences of everyday life. You reflect on how messages about chemicals influence and structure our lives and why some chemicals are celebrated and some are condemned. Using a second-person narrative voice, you show how the personal is relational and the chemical is cultural. You write because you seek a connection, a chemical bond.

  6. 不同碳源催化化学气相沉积制备自支撑C/Ni-Fiber复合电极材料的电容脱盐性能%Self-supporting Macroscopic Carbon/Ni-Fiber Hybrid Electrodes Prepared by Catalytic Chemical Vapor Deposition Using Various Carbonaceous Compounds and Their Capacitive Deionization Performance

    Institute of Scientific and Technical Information of China (English)

    王喜文; 姜芳婷; 索全伶; 方玉珠; 路勇

    2011-01-01

    以甲烷、乙烯、乙醇和正丁醇为碳源,通过催化化学气相沉积在具有三维开放网络结构的烧结8 μm-Ni金属纤维上沉积碳的方法,制备了以金属Ni纤维网络为集流极、沉积碳为离子存储库的薄层大面积自支撑C/Ni-fiber复合电极材料.用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、热重分析(TGA)、X射线衍射(XRD)、N2-吸脱附等温线和循环伏安与电化学阻抗谱对电极材料进行了表征,并考察了其作为电极的电容脱盐性能.乙烯、甲烷、正丁醇和乙醇为碳源的沉积碳形态分别为鱼骨状碳纳米管(CNTs)、石墨烯面取向与轴平行的CNTs、棒状和蠕虫状碳纳米纤维(CNFs).C/Ni-fiber复合电极材料对NaCl的电吸附容量顺序为:乙烯>正丁醇>甲烷>乙醇,这与复合电极的电化学特性、孔结构和碳的纳米结构相关.在1.2V的工作电压下,以乙烯为碳源制备的C/Ni-fiber复合电极材料对水溶液中NaCl (100 mg·L-1)的电吸附容量达159 μmol·g-1.%We prepared a series of self-supported macroscopic C/Ni-fiber hybrid electrodes by catalytic chemical vapor deposition (CCVD) using methane, ethylene, ethanol and n-butanol as carbon sources to embed carbon onto a three-dimensional network of sinter-locked conductive 8 um-nickel fibers. For the as-prepared hybrid electrodes, the Ni-microfibrous network serves as a current collector and the carbons as ion storage media while the macroporous void space serves as an electrolyte reservoir. We characterized the hybrid electrodes using scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), X-ray diffraction (XRD), N2 isothermal adsorption-desorption, cyclic voltammetry and electrochemical impedance spectroscopy. The desalination performance of the C/Ni-fiber hybrids was evaluated as electrodes in a capacitive deionization system. The carbon morphology is dependent on the carbonaceous compounds

  7. Access cavity preparation.

    Science.gov (United States)

    Adams, N; Tomson, P L

    2014-03-01

    Each stage of root canal treatment should be carried out to the highest possible standard. The access cavity is arguably the most important technical stage, as subsequent preparation of the root canal(s) can be severely comprised if this is not well executed. Inadequate access can lead to canals being left untreated, poorly disinfected, difficult to shape and obturate, and may ultimately lead to the failure of the treatment. This paper highlights common features in root canal anatomy and outlines basic principles for locating root canals and producing a good access cavity. It also explores each phase of the preparation in detail and offers suggestions of instruments that have been specifically designed to overcome potential difficulties in the process. Good access design and preparation will result in an operative environment which will facilitate cleaning, shaping and obturation of the root canal system in order to maximise success.

  8. Surface preparation of niobium

    International Nuclear Information System (INIS)

    Any discussion of surface preparation for superconducting rf-surfaces is certainly connected with the question what is the best recipe for achieving high Q-values and high break-down fields. Since the break-down in a cavity is not understood so far and because several mechanisms play a role, it also is not possible to give one recipe which always works. Nevertheless in the past certain preparation techniques for niobium surfaces have been developed and certain rules for preparation can be applied. In the following the to-days state of the art will be described and it is attempted to give a short description of the surface in conjunction with the methods of surface treatments, which generally can be applied to niobium cavities. (orig./WTR)

  9. Influence of Ammonia Concentration on Morphology, Structure and Properties of Zn( O, S) Films Prepared by Chemical Bath Deposition%氨水浓度对化学浴沉积的Zn(O,S)薄膜形貌、结构和性能的影响

    Institute of Scientific and Technical Information of China (English)

    刘军; 魏爱香; 招瑜; 刘俊; 庄米雪

    2012-01-01

    The Zn(O,S) thin films were prepared by chemical bath deposition (CBD) using ZnSO4 o 7H2O and SC(NH2)2 as the precursors, C6H5O7Na3 o 2H2O as the complexing agent, NH3 o H2O as the auxiliary complexing agent and buffer agent. The obtained thin films were characterized by scanning electron microscopy (SEM) , energy dispersive spectrometer (EDS) , X-ray diffraction (XRD) and UV-Vis spectrophotometry. The morphology, structure and optical properties of Zn (O, S) thin films were investigated as a function of ammonia concentration in precursors. The results reveal that Zn( O,S) films are composed of ZnO nano-particles and ZnS nano-particles. ZnO is wurtzite structure and ZnS is amorphous. As the ammonia concentration decreasing, the proportion of ZnO decreases while that of ZnS increases gradually. In the meanwhile, S/Zn atom ratios, transmission and optical band gap all increase.%采用化学浴法,以ZnSO4·7H2O和SC( NH2)2作为反应前驱物,C6H5O7 Na3·2H2O作为络合剂,NH3·H2O 作为辅助络合剂和缓冲剂制备Zn(O,S)薄膜.采用SEM、EDS、XPS、XRD和透射光谱分析方法,研究氨水浓度对化学浴法制备的Zn(O,S)薄膜形貌、成分、结构和光学性能的影响以及Zn(O,S)薄膜的形成机理.结果表明:Zn(O,S)薄膜是由ZnO和ZnS纳米颗粒混合组成的,ZnO具有纤锌矿结构,ZnS是以非晶相存在.随着反应溶液中氨水浓度的降低,薄膜中所包含的ZnO逐渐减少,ZnS逐渐增加,S/Zn原子比逐渐增加,透射率和光学带隙也逐渐增大.

  10. Design of chemical plant

    International Nuclear Information System (INIS)

    This book describes design of chemical plant, which includes chemical engineer and plan for chemical plant, development of chemical process, cost engineering pattern, design and process development, general plant construction plan, project engineering, foundation for economy on assets and depreciation, estimation for cost on capital investment and manufacturing cost, design with computers optimal design and method like fluid mechanics design chemical device and estimation for cost, such as dispatch of material and device writing on design report and appendixes.

  11. N-Methylcysteine-Mediated Total Chemical Synthesis of Ubiquitin Thioester

    OpenAIRE

    Erlich, Lesly A.; Ajish Kumar, K. S.; Haj-Yahya, Mahmood; Dawson, Philip E.; Brik, Ashraf

    2010-01-01

    Ubiquitin thioester is a key intermediate in the ubiquitylation of proteins and is formed enzymatically through the activation of α-COOH of ubiquitin in an ATP dependent manner using the E1 enzyme. The current methods used for the preparation of ubiquitin thioester rely on either the enzymatic machinery or on expressed protein ligation technology. In this article, we report a new chemical strategy, combining native chemical ligation and N-methylcysteine containing peptides, to chemically prep...

  12. Preparation of hydrophobic coatings

    Science.gov (United States)

    Branson, Eric D.; Shah, Pratik B.; Singh, Seema; Brinker, C. Jeffrey

    2009-02-03

    A method for preparing a hydrophobic coating by preparing a precursor sol comprising a metal alkoxide, a solvent, a basic catalyst, a fluoroalkyl compound and water, depositing the precursor sol as a film onto a surface, such as a substrate or a pipe, heating, the film and exposing the film to a hydrophobic silane compound to form a hydrophobic coating with a contact angle greater than approximately 150.degree.. The contact angle of the film can be controlled by exposure to ultraviolet radiation to reduce the contact angle and subsequent exposure to a hydrophobic silane compound to increase the contact angle.

  13. Wet chemical thinning of molybdenum disulfide down to its monolayer

    Directory of Open Access Journals (Sweden)

    Kiran Kumar Amara

    2014-09-01

    Full Text Available We report on the preparation of mono- and bi-layer molybdenum disulfide (MoS2 from a bulk crystal by facile wet chemical etching. We show that concentrated nitric acid (HNO3 effectively etches thin MoS2 crystals from their edges via formation of MoO3. Interestingly, etching of thin crystals on a substrate leaves behind unreacted mono- and bilayer sheets. The flakes obtained by chemical etching exhibit electronic quality comparable to that of mechanically exfoliated counterparts. Our findings indicate that the self-limiting chemical etching is a promising top-down route to preparing atomically thin crystals from bulk layer compounds.

  14. Sperm preparation for fertilization

    NARCIS (Netherlands)

    Gadella, B.M.

    2014-01-01

    Description This book contains 19 chapters that discuss theoretical and applied andrology for domestic, zoo and wild animals. Topics include semen and its constituents; sperm production and harvest; determinants of sperm morphology; sperm preparation for fertilization; practical aspects of semen cry

  15. Preparing Global Citizens

    Science.gov (United States)

    Roberts, Dennis C.; Welch, Lucas; Al-Khanji, Khalid

    2013-01-01

    Global citizens are those who are aware of, demonstrate respect for, and are comfortable engaging across cultural boundaries. This article explores why preparing global citizens is important and how positive psychology can inform our understanding of those who engage comfortably in today's complicated world. Soliya's Connect program is described…

  16. Teaching Preparation Program (TPP).

    Science.gov (United States)

    California Univ., Los Angeles. Dept. of Geography.

    Because most graduate geography students will engage in professional teaching activities, the Teaching Preparation Program of UCLA's department of geography is viewed as an important part of graduate training. The program, co-directed by a graduate student and faculty member, is available to all graduate students on a voluntary basis and consists…

  17. Method for preparing superconductors

    Science.gov (United States)

    Dahlgren, Shelley D.

    1976-01-01

    A superconductor having an equiaxed fine grain beta-tungsten crystalline structure found to have improved high field critical current densities is prepared by sputter-depositing superconductive material onto a substrate cooled to below 200.degree. C. and heat-treating the deposited material.

  18. Preparing for CLIC tests

    CERN Multimedia

    Laurent Guiraud

    1999-01-01

    The Canon 5 undergoes first brazing for preparation in the CLIC study at the CLIC Test Facility 2 (CTF2). This will test injection for a proposed linear collider that will further explore discoveries made at the LHC. Electric fields in the canon will boost electrons into the acceleration fields of the collider.

  19. THE USE OF CHEMICALS AS INSECTICIDES--PLANTS. AGRICULTURAL CHEMICALS TECHNOLOGY, NUMBER 2.

    Science.gov (United States)

    Ohio State Univ., Columbus. Center for Vocational and Technical Education.

    THIS GUIDE IS ONE OF A SERIES DESIGNED TO PROVIDE GROUP INSTRUCTION AND INDIVIDUAL OCCUPATIONAL EXPERIENCE FOR POST-SECONDARY STUDENTS PREPARING FOR EMPLOYMENT AS AGRICULTURAL CHEMICAL TECHNICIANS. IT WAS DEVELOPED BY A NATIONAL TASK FORCE ON THE BASIS OF STATE STUDY DATA. THE OBJECTIVES ARE TO DEVELOP (1) INTEREST, APPRECIATION, AND UNDERSTANDING…

  20. Advances in chemical physics

    CERN Document Server

    Rice, Stuart A

    2012-01-01

    The Advances in Chemical Physics series-the cutting edge of research in chemical physics The Advances in Chemical Physics series provides the chemical physics field with a forum for critical, authoritative evaluations of advances in every area of the discipline. Filled with cutting-edge research reported in a cohesive manner not found elsewhere in the literature, each volume of the Advances in Chemical Physics series serves as the perfect supplement to any advanced graduate class devoted to the study of chemical physics. This volume explores: Quantum Dynamical Resonances in Ch