WorldWideScience

Sample records for chemical preparation

  1. Substrates: Chemical characteristics and preparation

    NARCIS (Netherlands)

    Sonneveld, C.; Voogt, W.

    2009-01-01

    In this chapter the characteristics of substrates will be discussed with respect to their effects on plant nutrition. Therefore, the chemical composition will be taken into account in the first place, because the mineral elements present in the material can be directly available to plants or can bec

  2. [Responsibilities of enterprises introducing new dangerous chemical substances and preparations].

    Science.gov (United States)

    Cieśla, Jacek; Majka, Jerzy

    2004-01-01

    The paper reviews the responsibilities of producers, importers and distributors set in a new Act of January 2001 on chemical substances and preparations (Off. J. 2001, No. 11, item 84, with subsequent amendments). This Act together with executive provisions is aimed at harmonizing Polish legislation with EU requirements. The Act sets conditions, restriction and bans of production placing on the market and use of chemical substances and preparations in order to protect human health and environment against their harmful effects. The Act together with a number of executive provisions render those who introduce dangerous chemicals and chemical preparations, including distributors responsible for: classification and labelling of dangerous chemical substances and preparations; possessing, making available and up-dating safety data sheets; supplying packages containing certain dangerous substances with child-proof fastenings; notifying the Inspector for Chemical Substances and Preparations about placing a dangerous preparation on the market; notifying the Inspector about a new substance and conducting required studies; being properly qualified to handle dangerous substances. The Act strictly defines the term "placing a substance or a preparation on the market"--it means making a substance or a preparation available to third parties on the territory of The Republic of Poland, territories of the Member States of the European Union or the territory of Iceland, Liechtenstein and Norway, unless the Act provides otherwise; it also means introduction of a substance or a preparation from outside of the territory referred to above on the customs territory of The Republic of Poland, or that of the member states of the European Union and other states listed above. In addition, some of the responsibilities defined by the provisions of the law on chemical substances and preparations are also applicable to handling of biocidals, which are classified as dangerous substances. The Act

  3. 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. ....... Densities of up to 75% of that of bulk Fe-B have been obtained. Coercivity measurements show that the material is not magnetically soft....

  4. Preparation of liquid fuels from chark chemical tar

    Directory of Open Access Journals (Sweden)

    Zhaksyntay Kairbekov

    2012-12-01

    Full Text Available In the course of study the optimal conditions of conduction of the process hydrogenization are found. Optimal temperature for preparation of motor oils from chark chemical tar is 4000С. On the increase of temperature from 3500С to 4000С the yield of liquid products on Mo-containing catalyst increases from 47.1 mass. % to 65.2 mass. % compared to the yield of liquid products obtained without the catalyst. The yield of gasoil fraction constitutes 15 mass. %. Optimal quantity of catalyst for preparation of liquid products from the tar is 0.05 mass. %. According to the results of study the catalytic effect of synthesized from emulsion catalyst appears at low concentration of molybdenum (0.05 mass.%. But the double increase of concentration of molybdenum weakly effects the improvement of indicators of the process.

  5. Preparation of calcium stannate by modified wet chemical method

    Institute of Scientific and Technical Information of China (English)

    何则强; 李新海; 刘恩辉; 侯朝辉; 邓凌峰; 胡传跃

    2003-01-01

    A modified wet chemical route for low-temperature synthesis of the calcium stannate CaSnO3, a potentialmaterial for dielectric applications is reported. Firstly, a precursor CaSn(OH)6 was prepared using tin tetrachloride,calcium chloride and sodium hydroxide at room temperature. Then the precursor was annealed at relatively low tem-perature of 600 ℃ to obtain CaSnO3. The phase identification, thermal behavior and surface morphology of the sam-ples were characterized by element analysis, X-ray diffraction (XRD), thermo-gravimetric (TG) analysis and deriva-tive thermo-gravimetric (DTG) analysis, Fourier transform infrared spectroscopy (FTIR) and scanning electron mi-croscopy (SEM) in detail. The results show that CaSnO3 obtained by this method possesses a cubic perovskitestructure with average grain size of 5 μm.

  6. Radiation-chemical preparation of poly(vinyl alcohol) hydrogels

    Science.gov (United States)

    Duflot, Anastasia V.; Kitaeva, Natalia K.; Duflot, Vladimir R.

    2015-02-01

    This work reports the usage of method of radiation-chemical synthesis to prepare cross-linked hydrogels from poly(vinyl alcohol) modified with glycidyl methacrylate. Synthesis kinetics of modified poly(vinyl alcohol) and properties of hydrogels were studied. The gel fraction, swelling, mechanical properties, and water content of the hydrogels were measured. It was found that gel fraction increases with increasing radiation dose, concentration of modified poly(vinyl alcohol), and reaches 60%. It was established by differential scanning calorimetry that a fraction of the "bound" water in hydrogels is 50-70% and independent of gel fraction content. In addition to "bound" and "free" states, water in hydrogels is also present in the intermediate state.

  7. 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.

  8. Bioactive carbon-PEEK composites prepared by chemical surface treatment.

    Science.gov (United States)

    Miyazaki, Toshiki; Matsunami, Chisato; Shirosaki, Yuki

    2017-01-01

    Polyetheretherketone (PEEK) has attracted much attention as an artificial intervertebral spacer for spinal reconstruction. Furthermore, PEEK plastic reinforced with carbon fiber has twice the bending strength of pure PEEK. However, the PEEK-based materials do not show ability for direct bone bonding, i.e., bioactivity. Although several trials have been conducted for enabling PEEK with bioactivity, few studies have reported on bioactive surface modification of carbon-PEEK composites. In the present study, we attempted the preparation of bioactive carbon-PEEK composites by chemical treatments with H2SO4 and CaCl2. Bioactivity was evaluated by in vitro apatite formation in simulated body fluid (SBF). The apatite formation on the carbon-PEEK composite was compared with that of pure PEEK. Both pure PEEK and carbon-PEEK composite formed the apatite in SBF when they were treated with H2SO4 and CaCl2; the latter showed higher apatite-forming ability than the former. It is conjectured that many functional groups able to induce the apatite nucleation, such as sulfo and carboxyl groups, are incorporated into the dispersed carbon phase in the carbon-PEEK composites.

  9. Preparation of Chemical Samples On Relevant Surfaces Using Inkjet Technology

    Science.gov (United States)

    2013-04-01

    moisture is absorbed by the chemical from the air. The weight eventually stabilizes as the chemical moisture content approaches that of the air. This...when similar chemical solutions are paint -sprayed onto a hot (70 °C) substrate, the crystals are smaller, more numerous, and more closely spaced. To...gravity, surface tension, particle size, and chemical composition. Substrate material may be wood, metal, glass, plastic, concrete, road blacktop, dirt

  10. Preparation

    Directory of Open Access Journals (Sweden)

    M.M. Dardir

    2014-03-01

    Full Text Available Some hexanamide-mono and di-linoleniate esters were prepared by the reaction of linolenic acid and hexanamide (derived from the reaction of hexanoic acid and diethanolamine. The chemical structure for the newly prepared hexanamide-mono and di-linoleniate esters were elucidated using elemental analysis, (FTIR, H 1NMR and chemical ionization mass spectra (CI/Ms spectroscopic techniques. The results of the spectroscopic analysis indicated that they were prepared through the right method and they have high purity. The new prepared esters have high biodegradability and lower toxicity (environmentally friendly so they were evaluated as a synthetic-based mud (ester-based mud for oil-well drilling fluids. The evaluation included study of the rheological properties, filtration and thermal properties of the ester based-muds formulated with the newly prepared esters compared to the reference commercial synthetic-based mud.

  11. 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

  12. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Brusasco, R.M.

    1989-01-01

    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.

  14. Sample preparation for combined chemical analysis and bioassay application in water quality assessment

    NARCIS (Netherlands)

    Kolkman, A.; Schriks, M.; Brand, W; Bäuerlein, P.S.; van der Kooi, M.M.E.; van Doorn, R.H.; Emke, E.; Reus, A.; van der Linden, S.; de Voogt, P.; Heringa, M.B.

    2013-01-01

    The combination of in vitro bioassays and chemical screening can provide a powerful toolbox to determine biologically relevant compounds in water extracts. In this study, a sample preparation method is evaluated for the suitability for both chemical analysis and in vitro bioassays. A set of 39 chemi

  15. Sheet resistances of composite films prepared from chemically-reduced graphite oxides and multiwalled carbon nanotubes

    Science.gov (United States)

    Oh, Weontae; Kim, Daehan; Jeong, Euh Duck; Bae, Jong-Seong

    2013-12-01

    Graphite oxides (GOs) were spray-coated on a glass substrate to prepare the GO film, and the film was soaked in a HI aqueous solution to make a chemically-reduced GO (rGO) film. The rGOs were successfully prepared by using a chemical reduction of as-made GOs, but their surfaces were seriously damaged during the chemical treatments. The Sheet resistances of rGO and rGO/multiwalled carbon nanotube (MWNT) films were characterized as functions of the film's thickness and the number of MWNTs added to the rGO films.

  16. 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.

  17. PREPARATION OF CHEMICALLY WELL-DEFINED CARBOHYDRATE DENDRIMER CONJUGATES

    DEFF Research Database (Denmark)

    2004-01-01

    A method for the synthesis of dendrimer conjugates having a well-defined chemical structure, comprising one or more carbohydrate moieties and one or more immunomodulating substances coupled to a dendrimer, is presented. First, the carbohydrate is bound to the dendrimer in a chemoselective manner....... Subsequently, the immunomodulating substance is also bound in a chemoselective manner, to give a dendrimer conjugate with a well-defined structure and connectivity and containing a precise, pre-determined ratio of carbohydrate to immunomodulating substance. The invention also relates to novel dendrimer...

  18. 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)

  19. 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.

  20. 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.

  1. 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.

  2. [Chemical and nutritional changes during preparation of whole corn tortillas prepared with instant flour obtained by extrusion process].

    Science.gov (United States)

    Gómez Aldapa, C A; Martínez Bustos, F; Figueroa Cárdenas, J D; Ordorica Falomir, C A; González Hernández, J

    1996-12-01

    Chemical changes of some nutritional components (protein, total dietary fiber, vitamins, lysine, tryptophan, ether extract and fatty acids) of tortillas made from instant whole corn flour prepared by extrusion process (CINVESTAV process) were evaluated. The tortillas prepared by extrusion process were compared with tortillas made by traditional process and raw corn. The protein content of tortillas from both processes were statistically similar to those of the raw corn, although the traditional tortillas showed the lowest actual values. Tortillas from traditional process contained the lowest amount of total dietary fiber and available lysine. The loss of protein, crude fiber, total dietary fiber, available lysine, tryptophan, and vitamin contents during traditional tortillas process, was attributable to the partial loss of pericarp, aleurone and germ tissue during the process. Tortillas prepared by both processes showed loss of vitamins. The thermal treatment in both processes (traditional and extrusion) decreased the ether extract and fatty acids contents. Tortillas prepared by extrusion process showed better nutritional characteristics than traditional tortillas prepared by nixtamalization process.

  3. Effect of Chemical Parameters on the Properties of Hydrogels Prepared by using Gamma Radiation Polymerization

    Directory of Open Access Journals (Sweden)

    MOHAMMAD SADEGHI

    2012-12-01

    Full Text Available Several hydrogels were prepared using radiolytic polymerization of aqueous solutions of 2-acrylamido-2-methylpropanesulfonic acid containing appropriate comonomer such as acrylic acid and collagen. The hydrogels have been prepared at an irradiation dose of 25 kGy. The effects of the chemical structure of the monomer(s and crosslinking agent on the yield of homopolymer(s or copolymers and reaction time have been studied. This crosslinking agent include N, N’-methylene bisallyamide (MBA.

  4. 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...

  5. Transparent heat insulating coatings on polyester film using chemically-prepared dielectrics

    Energy Technology Data Exchange (ETDEWEB)

    Chiba, K.; Sobajima, S.; Yatabe, T.

    1983-03-01

    Dielectric/metal/dielectric coatings have been formed on a polyethylene terephthalate (polyester) film using chemical and physical preparation techniques. Hydrolysis of tetra n-butyl titanate followed by condensation gave rise to a uniform transparent dielectric layer with relatively high refractive index. The metal layer was prepared by vacuum evaporation or dc-magnetron sputtering. Effects of coating parameters including solvents, thickness uniformity and carbon residues on optical properties are discussed. Prepared coatings have exhibited good spectral selectivities, i.e., transparent heat mirror characteristics; solar energy transmittance is 55-76%, and ir-reflectance at 10 micrometer wavelength is 72-97%.

  6. 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.

  7. Antimony sulfide thin films prepared by laser assisted chemical bath deposition

    Science.gov (United States)

    Shaji, S.; Garcia, L. V.; Loredo, S. L.; Krishnan, B.; Aguilar Martinez, J. A.; Das Roy, T. K.; Avellaneda, D. A.

    2017-01-01

    Antimony sulfide (Sb2S3) thin films were prepared by laser assisted chemical bath deposition (LACBD) technique. These thin films were deposited on glass substrates from a chemical bath containing antimony chloride, acetone and sodium thiosulfate under various conditions of normal chemical bath deposition (CBD) as well as in-situ irradiation of the chemical bath using a continuous laser of 532 nm wavelength. Structure, composition, morphology, optical and electrical properties of the Sb2S3 thin films produced by normal CBD and LACBD were analyzed by X-Ray diffraction (XRD), Raman Spectroscopy, Atomic force microscopy (AFM), X-Ray photoelectron spectroscopy (XPS), UV-vis spectroscopy and Photoconductivity. The results showed that LACBD is an effective synthesis technique to obtain Sb2S3 thin films for optoelectronic applications.

  8. [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.

  9. 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

    Cobalt oxide films were grown by Pulsed Injection Metal Organic Chemical Vapour Deposition (PI-MOCVD) using Co(acac)(3) (acac=acetylacetonate) precursor dissolved in toluene. The structure, morphology and growth rate of the layers deposited on silicon substrates were studied as a function...... of 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...

  10. Thin Films with Low Zn Content Prepared by Chemical Bath Deposition

    Directory of Open Access Journals (Sweden)

    Caijuan Tian

    2012-01-01

    Full Text Available Chemical bath deposition (CBD was used for the growth of thin films with low Zn content. The influence of preparation conditions, such as pH, temperature, and concentration, on film properties was investigated. The chemical growth mechanism of thin films was analyzed, and optimized growth conditions for the thin films were established. The fill factor and short-circuit current were improved while was used to replace CdS as the window layer in CdTe solar cells.

  11. 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.

  12. 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.

  13. Preparation of nanosized sililcon carbide powders by chemical vapor deposition at low temperatures

    Institute of Scientific and Technical Information of China (English)

    LI Bin; ZHANG Changrui; HU Haifeng; QI Gongjin

    2007-01-01

    Liquid carbosilane was synthesized and analyzed by infrared(IR) and H-NMR(nuclear magnetic resonance)spectroscopy.Silicon carbide(SiC)powders were prepared by chemical vapor deposition (CVD)at 850℃ and 900℃ from liquid carbosilanes.The product powders were characterized by IR spectroscopy,X-ray diffractometry(XRD)and scanning electron microscopy (SEM).Results show that liquid carbosilane synthesized was the mixture of several oligomers that had a Si-C backbone.The powders prepared at 850℃ contain some organic segments,and those prepared at 900℃ are pure nanosized SiC powders,which are partly crystallized,the size of which is about 50-70 nm.

  14. 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.

  15. 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 ...

  16. Physical and Chemical Stability of Mycophenolate Mofetil (MMF) Suspension Prepared at the Hospital.

    Science.gov (United States)

    Fahimi, Fanak; Baniasadi, Shadi; Mortazavi, Seyed Alireza; Dehghan, Hanie; Zarghi, Afshin

    2012-01-01

    To evaluate the physical and chemical stability of a suspension of mycophenolate mofetil (MMF) prepared in the hospital from commercially available MMF capsules and tablets. Extemporaneous pharmacy was used as a feasible method in this experimental study to prepare suspension form of MMF. Suspension formulations were prepared from both tablets and capsules forms of MMF. Thereafter the stability parameters such as pH, microbial control, thermal and physical stability and particle sizes were evaluated. The amount of MMF, in the suspension was measured at various time points by HPLC. The HPLC method showed that concentration of suspensions prepared from tablets and capsules were 49 mg/mL and 50 mg/mL at time 0, respectively. The effective amount of suspensions prepared from capsules was 101% at time 0, 100% after 7 days, 98% after 14 days, and less than 70% after 28 days. According to the obtained results in this study, capsule-based suspension was stable for as long as 14 days at 5°C. This formulation appears to be clinically acceptable and provides a convenient dosage form for pediatric patients and for adults during the early postoperative period.

  17. Preparation of melanin from Catharsius molossus L. and preliminary study on its chemical structure.

    Science.gov (United States)

    Xin, Chao; Ma, Jia-hua; Tan, Cheng-jia; Yang, Zhou; Ye, Feng; Long, Chan; Ye, Shuang; Hou, Da-bin

    2015-04-01

    A great deal of melanin was found in the waste alkali liquor produced by extraction of chitin from Catharsius molossus L. Discarding the lye could harm the environment and cause waste of resources. In this paper, melanin from C. molossus L. was recovered through acid precipitation and purified by pepsin and so on. The purity, chemical composition and structure of the prepared melanin were explored by UV-visible absorption spectroscopy, Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, high resolution (13)C Cross polarization magic angle spinning nuclear magnetic resonance spectroscopy pyrolysis gas chromatography mass spectrometry, X ray diffraction, X ray fluorescence, matrix-assisted laser desorption/ionization time of flight tandem mass spectrometry, thermal analysis, and so on. The results showed that the purity of the prepared melanin was higher than the commercial standard melanin and it was a kind of nanoaggregates composed of a large quantity of 5,6-dihydroxyindole eumelanin and a small amount of phaeomelanin. In addition, the prepared melanin was irregular in shape and its structure could be divided into three levels: advanced structure maintained by polypeptides, substructure maintained by the ferric ion and microstructure. In particular, the smallest structural unit showed the graphite-like layered structure containing five layers linked by non-covalent bonds and each layer mainly consisted of 5,6-dihydroxyindole and its derivatives, which might be connected to each other through various chemical bonds.

  18. 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.

  19. Preparation and properties of the magnetic absorbent polymer via the chemical transformation process

    Science.gov (United States)

    Liu, Shengyu; Zhang, Suhong; Guo, Jianying; Wen, Jing; Qiao, Yan

    2017-01-01

    Magnetic polyacrylic acid sodium polymer (MPAAS) was prepared by chemical transformation method. Key parameters were investigated in the synthesis process of the magnetic polymer and an optimum preparation condition was gained. The structure of the magnetic polymer was characterized by X-ray diffraction (XRD), Fourier transform infrared spectrosocopy (FTIR) and scanning electron microscope (SEM). Magnetic property of the magnetic polymer was measured by the magnet and superconducting quantum interference device (SQUID). Both the swelling ratio and kinetics and the water retention ratio and kinetics were investigated. Based on the results, it can be gained that both swelling rate and equilibrium swelling rate were lowered after magnetization while the water retention ability of the magnetic polymer is stronger than that of the polymer.

  20. 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.)

  1. 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.

  2. Chemical preparation and investigation of Fe-P-B ultrafine amorphous alloy particles

    Institute of Scientific and Technical Information of China (English)

    胡征; 吴勇; 范以宁; 颜其洁; 陈懿

    1997-01-01

    A series of Fe-P-B ultrafine amorphous alloy particles has been prepared by the chemical reduction method The composition and size of the particles have been effectively adjusted.Mossbauer spectroscopy in addition to sonic other techniques has been used to investigate the reaction process,the factors that influence the preparation,the crystallization of the particles,and the interactions between the components within them.The results indicate that the co-deposition of iron,phosphorus and boron atoms in the solution at room temperature forms Fe-P-B amorphous alloy particles,and a preferential bonding of Fe-P bond to Fe-B one exists in the particles.

  3. 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.

  4. High-purity cobalt thin films with perpendicular magnetic anisotropy prepared by chemical vapor deposition

    Science.gov (United States)

    Ootera, Yasuaki; Shimada, Takuya; Kado, Masaki; Quinsat, Michael; Morise, Hirofumi; Nakamura, Shiho; Kondo, Tsuyoshi

    2015-11-01

    A study of the chemical vapor deposition (CVD) of high-purity cobalt thin films is described. The Co layer prepared by a thermal CVD technique with a Pt/Ta underlayer and a Pt cap layer shows a saturation magnetization (Ms) of ∼1.8 T and perpendicular magnetic anisotropy (PMA) with an anisotropy energy (Ku) of ∼105 J/m3. The cobalt thickness dependence of Ku reveals that the interfacial anisotropy at the Pt/Co interface is most likely the origin of the obtained PMA.

  5. In-situ preparation of polymer-coated alumina nanopowders by chemical vapor synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Schallehn, M.; Winterer, M.; Weirich, T.E.; Hahn, H. [Inst. of Materials Science, Darmstadt Univ. of Technology, Darmstadt (Germany); Keiderling, U. [Hahn-Meitner-Inst., Berlin (Germany)

    2003-01-01

    Nanocrystalline alumina particles coated with polyethylene have been prepared by a two-step chemical vapor synthesis (CVS) process using a hot-wall reactor to synthesize the nanocrystalline alumina core, and a RF plasma reactor for the subsequent polymer coating. The particle radius is about 4 nm, with the radius of the ceramic core being about 2.5 nm and the coating thickness about 1.5 nm. The powders have been characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), small-angle neutron scattering (SANS), and high-resolution transmission electron microscopy (HRTEM). (orig.)

  6. 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.

  7. NiS/ZnS multilayer thinfilm prepared by chemical bath deposition method

    Science.gov (United States)

    Yuvaloshini, J.; Ravi, G.; Shanmugavadivu, Ra.

    2013-06-01

    NiS/ZnS multilayer thin films were prepared by Chemical Bath Deposition (CBD) technique by successive coatings of nickel, zinc and sulphur. The X-ray diffraction was used to obtain structural characterization for the multilayer thinfilms, the crystalline size of 50 nm. The Scanning Electron Microscope techniques were employed to study the internal structure and indentified as of hexagonal structure. An EDAX spectrum confirms the compositional analysis of nickel, zinc and sulphur in nominal composition. The photoluminescence behaviour of NiS/ZnS multilayered system consists in the superposition independent photoluminescence emission in blue shift.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 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%.

  14. Surface modification of silicon-containing fluorocarbon films prepared by plasma-enhanced chemical vapor deposition

    Science.gov (United States)

    Jin, Yoonyoung; Desta, Yohannes; Goettert, Jost; Lee, G. S.; Ajmera, P. K.

    2005-07-01

    Surface modification of silicon-containing fluorocarbon (SiCF) films achieved by wet chemical treatments and through x-ray irradiation is examined. The SiCF films were prepared by plasma-enhanced chemical vapor deposition, using gas precursors of tetrafluoromethane and disilane. As-deposited SiCF film composition was analyzed by x-ray photoelectron spectroscopy. Surface modification of SiCF films utilizing n-lithiodiaminoethane wet chemical treatment is discussed. Sessile water-drop contact angle changed from 95°+/-2° before treatment to 32°+/-2° after treatment, indicating a change in the film surface characteristics from hydrophobic to hydrophilic. For x-ray irradiation on the SiCF film with a dose of 27.4 kJ/cm3, the contact angle of the sessile water drop changed from 95°+/-2° before radiation to 39°+/-3° after x-ray exposure. The effect of x-ray exposure on chemical bond structure of SiCF films is studied using Fourier transform infrared measurements. Electroless Cu deposition was performed to test the applicability of the surface modified films. The x-ray irradiation method offers a unique advantage in making possible surface modification in a localized area of high-aspect-ratio microstructures. Fabrication of a Ti-membrane x-ray mask is introduced here for selective surface modification using x-ray irradiation.

  15. 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.

  16. 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.

  17. Characterization of Korean Red Ginseng (Panax ginseng Meyer: History, preparation method, and chemical composition

    Directory of Open Access Journals (Sweden)

    Sang Myung Lee

    2015-10-01

    Full Text Available It has been reported that Korean Red Ginseng has been manufactured for 1,123 y as described in the GoRyeoDoGyeong record. The Korean Red Ginseng manufactured by the traditional preparation method has its own chemical component characteristics. The ginsenoside content of the red ginseng is shown as Rg1: 3.3 mg/g, Re: 2.0 mg/g, Rb1: 5.8 mg/g, Rc:1.7 mg/g, Rb2: 2.3 mg/g, and Rd: 0.4 mg/g, respectively. It is known that Korean ginseng generally consists of the main root and the lateral or fine roots at a ratio of about 75:25. Therefore, the red ginseng extract is prepared by using this same ratio of the main root and lateral or fine roots and processed by the historical traditional medicine prescription. The red ginseng extract is prepared through a water extraction (90°C for 14–16 h and concentration process (until its final concentration is 70–73 Brix at 50–60°C. The ginsenoside contents of the red ginseng extract are shown as Rg1: 1.3 mg/g, Re: 1.3 mg/g, Rb1: 6.4 mg/g, Rc:2.5 mg/g, Rb2: 2.3 mg/g, and Rd: 0.9 mg/g, respectively. Arginine-fructose-glucose (AFG is a specific amino-sugar that can be produced by chemical reaction of the process when the fresh ginseng is converted to red ginseng. The content of AFG is 1.0–1.5% in red ginseng. Acidic polysaccharide, which has been known as an immune activator, is at levels of 4.5–7.5% in red ginseng. Therefore, we recommended that the chemical profiles of Korean Red Ginseng made through the defined traditional method should be well preserved and it has had its own chemical characteristics since its traditional development.

  18. 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.

  19. 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.

  20. Ultrasmooth gold surfaces prepared by chemical mechanical polishing for applications in nanoscience.

    Science.gov (United States)

    Miller, Michael S; Ferrato, Michael-Anthony; Niec, Adrian; Biesinger, Mark C; Carmichael, Tricia Breen

    2014-12-02

    For over 20 years, template stripping has been the best method for preparing ultrasmooth metal surfaces for studies of nanostructures. However, the organic adhesives used in the template stripping method are incompatible with many solvents, limiting the conditions that may subsequently be used to prepare samples; in addition, the film areas that can be reliably prepared are typically limited to ∼1 cm(2). In this article, we present chemical-mechanical polishing (CMP) as an adhesive-free, scalable method of preparing ultrasmooth gold surfaces. In this process, a gold film is first deposited by e-beam evaporation onto a 76-mm-diameter silicon wafer. The CMP process removes ∼4 nm of gold from the tops of the grains comprising the gold film to produce an ultrasmooth gold surface supported on the silicon wafer. We measured root-mean-square (RMS) roughness values using atomic force microscopy of 12 randomly sampled 1 μm × 1 μm areas on the surface of the wafer and repeated the process on 5 different CMP wafers. The average RMS roughness was 3.8 ± 0.5 Å, which is comparable to measured values for template-stripped gold (3.7 ± 0.5 Å). We also compared the use of CMP and template-stripped gold as bottom electrical contacts in molecular electronic junctions formed from n-alkanethiolate self-assembled monolayers as a sensitive test bed to detect differences in the topography of the gold surfaces. We demonstrate that these substrates produce statistically indistinguishable values for the tunneling decay coefficient β, which is highly sensitive to the gold surface topography.

  1. Preparation of γ-Al2O3 films by laser chemical vapor deposition

    Science.gov (United States)

    Gao, Ming; Ito, Akihiko; Goto, Takashi

    2015-06-01

    γ- and α-Al2O3 films were prepared by chemical vapor deposition using CO2, Nd:YAG, and InGaAs lasers to investigate the effects of varying the laser wavelength and deposition conditions on the phase composition and microstructure. The CO2 laser was found to mostly produce α-Al2O3 films, whereas the Nd:YAG and InGaAs lasers produced γ-Al2O3 films when used at a high total pressure. γ-Al2O3 films had a cauliflower-like structure, while the α-Al2O3 films had a dense and columnar structure. Of the three lasers, it was the Nd:YAG laser that interacted most with intermediate gas species. This promoted γ-Al2O3 nucleation in the gas phase at high total pressure, which explains the cauliflower-like structure of nanoparticles observed.

  2. 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.

  3. 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.

  4. 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.

  5. Preparation of 5N high purified indium by the method of chemical purification-electrolysis

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The application of indium requires high purity indium as material. 5N high purity indium had been prepared by the method of a combination of chemically smelting and electrolysis. Smelting time was 10 min, the abstraction rate of cadmium was 80%-90% when used solution of I2-KI and glycerine to smelt indium. 4N metal indium was used as anode, high purity indium as cathode, In2(SO4)3-H2SO4 system as electrolyte, and In content is 100 g/L, pH 2-3 and current density 80-100 A/m2. The thallium was removed by smelting indium using 15% NH4Cl-glycerine solution for 20 min and tin by smelting indium using NaOH and NaNO3 for 20 min. The removed rate of tin was 60%.The product quality of indium reached national standard of 5N high purity indium.

  6. Preparation and mechanism of calcium phosphate coatings on chemical modified carbon fibers by biomineralization

    Institute of Scientific and Technical Information of China (English)

    HUANG Su-ping; ZHOU Ke-chao; LI Zhi-you

    2008-01-01

    In order to prepare HA coatings on the carbon fibers, chemical modification and biomineralization processes were applied. The phase components, morphologies, and possible growth mechanism of calcium phosphate were studied by infrared spectroscopy(IR), X-ray diffractometry(XRD) and scanning electron microscopy(SEM). The results show that calcium phosphate coating on carbon fibers can be obtained by biomineralization. But the phase components and morphologies of calcium phosphate coatings are different due to different modification methods. Plate-like CaHPO4-2H2O (DCPD) crystals grow from one site of the active centre by HNO3 treatment. While on the para-aminobenzoic acid treated fibers, the coating is composed of nano-structural HA crystal homogeneously. This is because the -COOH functional groups of para-aminobenzoic acid graft on fibers, with negative charge and arranged structure, accelerating the HA crystal nucleation and crystallization on the carbon fibers.

  7. Tungsten-Carbon X-ray Multilayered Mirror Prepared by Photo-Chemical Vapor Deposition

    Science.gov (United States)

    Suzuki, Yoshihiko

    1989-05-01

    A tungsten-carbon(W/C) X-ray multilayered mirror was prepared by photoinduced chemical vapor deposition (photo-CVD) using a low-pressure mercury lamp and an argon-fluoride (ArF) excimer laser. The 40% reflectivity of this mirror was measured using a small-angle X-ray diffractometer with Cu-Kα radiation. This reflectivity is lower than the theoretical reflectivity of 80%. From observations of the transmission electron micrograph from this multilayered mirror, it seems that the reduction of the reflectivity was caused by the indistinct interfaces of the diffused films, and by the roughness of the films introduced by partial crystallization of the tungsten films.

  8. 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.

  9. 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.

  10. Faraday effect of polycrystalline bismuth iron garnet thin film prepared by mist chemical vapor deposition method

    Science.gov (United States)

    Yao, Situ; Kamakura, Ryosuke; Murai, Shunsuke; Fujita, Koji; Tanaka, Katsuhisa

    2017-01-01

    We have synthesized polycrystalline thin film composed of a single phase of metastable bismuth iron garnet, Bi3Fe5O12, on a fused silica substrate, one of the most widely utilized substrates in the solid-state electronics, by using mist chemical vapor deposition (mist CVD) method. The phase purity and stoichiometry are confirmed by X-ray diffraction and Rutherford backscattering spectrometry. The resultant thin film shows a small surface roughness of 3.251 nm. The saturation magnetization at room temperature is 1200 G, and the Faraday rotation angle at 633 nm reaches -5.2 deg/μm. Both the magnetization and the Faraday rotation angles are somewhat higher than those of polycrystalline BIG thin films prepared by other methods.

  11. 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.

  12. 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.

  13. Effect of additives on the properties of polyaniline nanofibers prepared by high gravity chemical oxidative polymerization.

    Science.gov (United States)

    Zhao, Yibo; Arowo, Moses; Wu, Wei; Chen, Jianfeng

    2015-05-12

    Polyaniline (PANI) nanofibers with improved properties were prepared by high gravity chemical oxidative polymerization in a rotating packed bed with the assistance of p-aminodiphenylamine (AD) and p-phenylenediamine (AP). The effects of reactor type, additive dosage, reaction temperature, and high-gravity level on the properties of products were investigated in detail. Three conclusions were made: (1) a small amount of additive can significantly improve some properties of the nanofibers such as uniformity, specific surface area, and specific capacitance; (2) in order to obtain high-quality nanofibers, the high-gravity level should coordinate with the reaction rate; (3) the molecular weight and conductivity of PANI decrease with the increase of additive dosage. The products have larger specific surface areas of up to 73.9 and 68.4 m(2)/g and consequently improved specific capacitance of up to 527.5 and 552 F/g for the PANI nanofibers prepared with AD and AP, respectively. However, the specific surface area and specific capacitance of pure PANI are only 49.1 m(2)/g and 333.3 F/g, respectively. This research provides a simple, reliable, and scalable method to produce PANI nanofibers of high performances.

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

    Directory of Open Access Journals (Sweden)

    Umair Manzoor

    Full Text Available 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 (< 20 nm dimensions with spherical morphology and narrow size distribution were successfully obtained after treating the mechano-chemically prepared samples at 250°C. However, higher temperature treatments produced larger particles. TEM, XRD and UV-Vis spectroscopy results suggested crystalline and phase pure ZnO. The NPs demonstrated promising antibacterial activity against Gram negative foodborne and waterborne bacterial pathogens i.e. Enteropathogenic E. coli (EPEC, Campylobacter jejuni and Vibrio cholerae as well as Gram positive methicillin 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.

  15. 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.

  16. 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)

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

    2015-01-01

    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

  17. 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

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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...

  4. 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

  5. Chemical and radiation crosslinked polymer electrolyte membranes prepared from radiation-grafted ETFE films for DMFC applications

    Science.gov (United States)

    Chen, Jinhua; Asano, Masaharu; Yamaki, Tetsuya; Yoshida, Masaru

    To develop a highly chemically stable polymer electrolyte membrane for application in a direct methanol fuel cell (DMFC), doubly crosslinked membranes were prepared by chemical crosslinking using bifunctional monomers, such as divinylbenzene (DVB) and bis(p, p-vinyl phenyl) ethane (BVPE), and by radiation crosslinking. The membranes were prepared by grafting of m, p-methylstyrene (MeSt) and p-tert-butylstyrene (tBuSt) into poly(ethylene- co-tetrafluoroethylene) (ETFE) films and subsequent sulfonation. The effects of the DVB and BVPE crosslinkers on the grafting kinetics and the properties of the prepared membranes, such as water uptake, proton conductivity and chemical stability were investigated. Radiation crosslinking was introduced by irradiation of the ETFE base film, the grafted film or the sulfonated membrane. The membrane crosslinked by DVB and BVPE crosslinkers and post-crosslinked by γ-ray irradiation of the corresponding grafted film possessed the highest chemical stability among the prepared membranes, a significantly lower methanol permeability compared to Nafion ® membranes, and a better DMFC performance for high methanol feed concentration. Therefore, this doubly crosslinked membrane was promising for application in a DMFC where relatively high methanol concentration could be fed.

  6. Chemical and radiation crosslinked polymer electrolyte membranes prepared from radiation-grafted ETFE films for DMFC applications

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jinhua; Asano, Masaharu; Yamaki, Tetsuya; Yoshida, Masaru [Department of Material Development, Takasaki Radiation Chemistry Research Establishment, Japan Atomic Energy Research Institute, 1233 Watanuki, Takasaki, Gunma 370-1292 (Japan)

    2006-07-14

    To develop a highly chemically stable polymer electrolyte membrane for application in a direct methanol fuel cell (DMFC), doubly crosslinked membranes were prepared by chemical crosslinking using bifunctional monomers, such as divinylbenzene (DVB) and bis(p,p-vinyl phenyl) ethane (BVPE), and by radiation crosslinking. The membranes were prepared by grafting of m,p-methylstyrene (MeSt) and p-tert-butylstyrene (tBuSt) into poly(ethylene-co-tetrafluoroethylene) (ETFE) films and subsequent sulfonation. The effects of the DVB and BVPE crosslinkers on the grafting kinetics and the properties of the prepared membranes, such as water uptake, proton conductivity and chemical stability were investigated. Radiation crosslinking was introduced by irradiation of the ETFE base film, the grafted film or the sulfonated membrane. The membrane crosslinked by DVB and BVPE crosslinkers and post-crosslinked by {gamma}-ray irradiation of the corresponding grafted film possessed the highest chemical stability among the prepared membranes, a significantly lower methanol permeability compared to Nafion{sup R} membranes, and a better DMFC performance for high methanol feed concentration. Therefore, this doubly crosslinked membrane was promising for application in a DMFC where relatively high methanol concentration could be fed. (author)

  7. 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.

  8. New Inorganic-organic Hybrid Tetravanadate:Preparation, Characterization and Application in Chemically Modified Electrode

    Institute of Scientific and Technical Information of China (English)

    SUN Ying-hua; LI Xiao-ping; MEI Ze-min; ZHU Yu; NIU Li

    2011-01-01

    A new inorganic-organic hybrid tetravanadate [Co(2,2'-bpy)3]2V4O12.llH2O(l) has been prepared and characterized. X-Ray diffraction study reveals that compound 1 contains classical cluster anions [V4O12]4-, coordi nated cations [Co(2,2'-bpy)3]2+ and eleven water molecules, in which an interesting decamer water cluster is formed.The hybrid nanoparticles were firstly used as a bulk-modifier to fabricate a chemically modified paste electrode (1-CPE). The electrochemical behavior and electrocatalysis of 1-CPE have been studied in detail. The results indicate that 1-CPE has a good electrocatalytic activity toward the reduction of bromate in a 0.5 mol/L H2SO4 aqueous solu tion. I-CPE shows remarkable stability that be ascribed to the hydrogen bonding interactions between V4O12 cluster and water cluster, which are very important for practical application in electrode modification.

  9. 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.

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

    Science.gov (United States)

    Kärber, Erki; Katerski, Atanas; Oja Acik, Ilona; Mikli, Valdek; Mere, Arvo; Sildos, Ilmo; Krunks, Malle

    2014-01-01

    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/cm(2)) 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.

  11. 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.

  12. Metal Organic Chemical Vapour Deposited Thin Films of Cobalt Oxide Prepared via Cobalt Acetylacetonate

    Institute of Scientific and Technical Information of China (English)

    C.U. Mordi; M.A. Eleruja; B.A. Taleatu; G.O. Egharevba; A.V. Adedeji; 0.0. Akinwunmi; B. Olofinjana; C. Jeynes; E.O.B. Ajayi

    2009-01-01

    The single solid source precursor, cobalt (Ⅱ) acetylacetonate was prepared and characterized by infrared spec-troscopy. Thin films of cobalt oxide were deposited on soda lime glass substrates through the pyrolysis (metal organic chemical vapour deposition (MOCVD)) of single solid source precursor, cobalt acetylaceto-nate, Co[C5H7O2]2 at a temperature of 420℃. The compositional characterization carried out by rutherford backscattering spectroscopy and X-ray diffraction (XRD), showed that the films have a stoichiometry of Co2O3 and an average thickness of 227±0.2 nm. A direct energy gap of 2.15±0.01 eV was calculated by the data obtained by optical absorption spectroscopy. The morphology of the films obtained by scanning electron mi-croscopy, showed that the grains were continuous and uniformly distributed at various magnifications, while the average grain size was less than 1 micron for the deposited thin films of cobalt oxide.

  13. 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.

  14. Structural properties of zinc oxide and titanium dioxide nanoparticles prepared by chemical vapor synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Akgul, Guvenc, E-mail: guvencakgul@gmail.com [Bor Vocational School, Nigde University, 51700 Nigde (Turkey); Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Akgul, Funda Aksoy [Physics Department, Nigde University, 51240 Nigde (Turkey); Attenkofer, Klaus [Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Winterer, Markus [Nanoparticle Process Technology, Department of Engineering Sciences, and Center for NanoIntegration Duisburg-Essen, CeNIDE, University of Duisburg-Essen (Germany)

    2013-03-25

    Highlights: ► Local structure determination of ZnO and TiO{sub 2} nanostructures by XANES and EXAFS. ► Zn K and Ti K absorption edge XANES investigations of nanopowder samples. ► Investigation of pre-edge peak features of TiO{sub 2} nanosamples. ► Obtaining of local structure parameters of nano ZnO and TiO{sub 2} using EXAFS. ► Good agreement of EXAFS results and crystal structure datas. -- Abstract: Transition metal (TM) oxides provide a wide range of functional materials especially when nanostructured. Titanium dioxide (TiO{sub 2}) and wurtzite type zinc oxide (ZnO) nanostructured materials were fabricated by chemical vapor synthesis (CVS). Crystal and local structures of the prepared nanosamples were ascertained using X-ray diffraction (XRD), X-ray absorption near edge structure (XANES), and extended X-ray absorption fine structure (EXAFS) techniques. Based on the XRD data, a second phase(s) was not found in both samples. A single wurtzite and anatase type structures were observed in ZnO and TiO{sub 2} nanosamples, respectively. Ti K pre-edge features of XANES spectrum indicated the presence of sixfold coordinated Ti in TiO{sub 2} nanosamples. The results showed that CVS is quite useful method to produce high crystalline nanoparticles.

  15. 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

  16. Chemical and plasma surface modification of lignocellulose coconut waste for the preparation of advanced biobased composite materials.

    Science.gov (United States)

    Kocaman, Suheyla; Karaman, Mustafa; Gursoy, Mehmet; Ahmetli, Gulnare

    2017-03-01

    In this study, surface-modified grinded coconut waste (CW) particles were used as bio-fillers to prepare polymeric composite materials with enhanced properties. Epoxy resin modified with acrylated and epoxidized soybean oil (AESO) was used as the polymer matrix. Two different strategies, namely chemical treatment and plasma enhanced chemical vapor deposition (PECVD) were utilized to modify the surface of CW particles for using them as compatible bio-fillers in composite preparation. Chemical modification involved the treatment of CW particles in a highly alkali NaOH solution, while PECVD modification involved coating of a thin film of hydrophobic poly(hexafluorobutyl acrylate) (PHFBA) around individual CW particle surfaces. Untreated and surface-modified CW particles were used in 10-50wt% for preparation of epoxy composites. FTIR analysis was performed to study the effect of modification on the structures of particles and as-prepared composites. The composite morphologies were investigated by XRD and SE. TGA test was conducted to study the thermal behavior of the composites. Also, the effects of CW particle surface modification on the mechanical and water sorption properties of epoxy resin composites were investigated in detail. It was observed that PECVD-treated CW particles had much more positive effects on the thermal, mechanical, wettability and flammability properties of composites.

  17. 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

  18. Aging in chemically prepared divalent silver oxide electrodes for silver/zinc reserve batteries

    Science.gov (United States)

    Smith, David F.; Brown, Curtis

    The instability of silver(II) oxide electrodes used in silver/zinc reserve batteries is the well known cause of capacity loss and delayed activation in reserve batteries after they are stored in the dry, unactivated state for extended periods of time. Metal contaminants in sintered/electroformed electrodes destabilize the oxide and the solid state reaction between AgO and elemental silver results in the formation of the lower capacity monovalent oxide Ag 2O. Chemically prepared (CP) AgO can be used to avoid the metal contaminants and to minimize the interfacial contact area between AgO and Ag, thus minimizing the affects of aging on the electrodes. Electrodes were fabricated with CP AgO and polytetrafluoroethylene (PTFE) binder and expanded silver metal current collectors. Experimentally, both electrode active material compacts (AgO and binder only) and electrodes complete with AgO/binder and silver current collector were tested to evaluate the influence of the current collector on aging. The electrode samples were discharged at a constant rate of 50 mA cm -2 before and after storage at 60°C for 21 days as well as after storage at room ambient temperature conditions for 91 months. The results indicate that the affects of aging upon the AgO/binder compacts are insignificant for long term storage at room temperature. However, thermally accelerated aging at high temperature (60°C) affects both transient and stabilized load voltage as well as capacity. In terms of capacity, the AgO/binder mix itself looses about 5% capacity after 21 days dry storage at 60°C while electrodes complete with current collector loose about 8%. The 60% increase in capacity loss is attributed to the solid state reaction between AgO and elemental silver.

  19. 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].

  20. 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.

  1. 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.

  2. Fabrication of GaAs symmetric pyramidal mesas prepared by wet-chemical etching using AlAs interlayer

    Science.gov (United States)

    Kicin, S.; Cambel, V.; Kuliffayová, M.; Gregušová, D.; Kováčová, E.; Novák, J.; Kostič, I.; Förster, A.

    2002-01-01

    We present a wet-chemical-etching method developed for the preparation of GaAs four-sided pyramid-shaped mesas. The method uses a fast lateral etching of AlAs interlayer that influences the cross-sectional profiles of etched structures. We have tested the method using H3PO4:H2O2:H2O etchant for the (100) GaAs patterning. The sidewalls of the prepared pyramidal structures together with the (100) bottom facet formed the cross-sectional angles 25° and 42° for mask edges parallel, resp. perpendicular to {011} cleavage planes. For mask edges turned in 45° according to the cleavage planes, 42° cross-sectional angles were obtained. Using the method, symmetric and more than 10-μm-high GaAs "Egyptian" pyramids with smooth tilted facets were prepared.

  3. 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.

  4. 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.

  5. 78 FR 4446 - Exempt Chemical Preparations Under the Controlled Substances Act

    Science.gov (United States)

    2013-01-22

    ...). American Radiolabeled Chemicals, Inc... 1,1-Dimethyltryptamine (1 mg/ Vial: 1 mL 12/22/2011 mL). American Radiolabeled Chemicals, Inc... 1,1-Dimethyltryptamine Vial: 1 mL 12/22/2011 -3H] as TFA salt....

  6. 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.

  7. CASHEW NUT SHELLS AS SOURCE OF CHEMICALS FOR PREPARATION OF CHALCOGENIDE NANOPARTICLES

    OpenAIRE

    MUBOFU E.B.; MLOWE S.; N. Revaprasadu

    2016-01-01

    Cashew nut shell wastes produced in cashew nut processing factories cause environmental problems. Currently, these wastes are being converted to a variety of bio-based chemicals and functional materials. Cashew nut shells (CNS) produce cashew nut shell liquid (CNSL), a dark reddish brown viscous liquid ( ca. 30 35 wt. %) which is extracted from the soft honeycomb of the CNS. CNSL offers multitude interesting possibilities for the synthesis of speciality chemicals, high value products and poly...

  8. Physical-chemical and biocatalytic properties of a proteolytic complex of the preparation "Protepsin"

    Directory of Open Access Journals (Sweden)

    L. V. Antipova

    2016-01-01

    Full Text Available Enzymatic technologies were included strongly into practical activities of the person, the volume of the world market constantly grows and is updated. However the domestic production of enzymatic preparations very lags behind world level that is in many respects connected with insufficient scientific and technical base for a wide circulation of technologies in large-scale production. At the same time there were Russian producers of enzymatic preparations from animal fabrics and bodies for processing of raw materials of an animal origin, according to forecasts, of interest in rational use of resources of an animal origin. In article data on research of properties of the enzymatic preparation "Protepsin" and an assessment of prospects of application are provided in processing of raw materials of an animal origin. The enzymatic preparation "Protepsin" made in the conditions of JSC Plant of Endocrine Enzymes (Rzhavki, Moscow region activity at action on proteins of meat shows, including the strengthened structure, has milk-clotting effect, is active in the field of pH 4,0-6,0 and temperature 20-45zs. The proteinaceous complex includes 4 fractions, 2 from which possess the general proteolytic activity. One of them shows the general proteolytic and milk-clotting activity. Enzymes differ in an amino-acid set and molecular weight. The method of a disk electrophoresis determined molecular-mass structure of "Protepsin". The preparation inactivation conditions guaranteeing its safety in the production technology of foodstuff as active proteolytic enzymes in the course of digestion can cause violations of integrity of fabrics and corresponding diseases are shown. Thus, conditions of use of a perspective proteolytic preparation in technology of a wide range of food of an animal origin are in a complex proved and picked up.

  9. Chemical composition of phase I Coxiella burnetii soluble antigen prepared by trichloroacetic acid extraction.

    Science.gov (United States)

    Lukácová, M; Brezina, R; Schramek, S; Pastorek, J

    1989-01-01

    Optimal conditions of extraction (time and temperature) by trichloroacetic acid of soluble antigen from phase I Coxiella burnetii (TCAE), possessing protective properties and used as a chemovaccine against Q fever in men, were studied. Extracts prepared under various conditions were analysed for their polysaccharide, protein and phosphorus contents. Forty-five min of extraction at 0 degrees C were sufficient to obtain a soluble antigen reacting in immunodiffusion with hyperimmune rabbit antiserum. The polysaccharide contents decreased with prolonged extraction at 0 degrees C. At higher extraction temperatures (37 and 100 degrees C), the polysaccharide contents increased while that of proteins decreased. TCAE prepared at 100 degrees C gave no positive immunodiffusion reaction.

  10. Preparation and Properties of Hydroxyethyl Methacrylate Chemically Modified Temperature-Sensitive Microgels

    Institute of Scientific and Technical Information of China (English)

    马晓梅; 席靖宇; 赵喜安; 唐小真

    2004-01-01

    A novel series of poly(N-isopropylacrylamide-co-hydroxyethyl methacrylate) (p(NIPAM-co-HEMA)) microgels were prepared through precipitation polymerization. Nuclear magnetic resonance (NMR), transmission electron microscopy (TEM), ultraviolet-visible spectroscopy (UV) and dynamic light scattering (DLS) were employed to characterize the microgels. The experimental results indicate that the prepared microgels with narrow distribution remain good temperature sensitivity after incorporation of functional -OH groups. In marked contrast to the general rule, incorporation of hydrophilic HEMA makes the volume-phase-transition temperature shift to the lower temperature due to the strong intermolecular H-bonding between amide and -OH groups, -OH and -OH groups.

  11. 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.

  12. 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.

  13. 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.

  14. 21 CFR 1308.23 - Exemption of certain chemical preparations; application.

    Science.gov (United States)

    2010-04-01

    ... special research purposes and not for general administration to a human being or other animal, if the... mixture must be formulated in such a manner that it incorporates methods of denaturing or other means so... with sufficient descriptive detail to identify the preparation or mixture (e.g., bottle, packet,...

  15. 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…

  16. Preparation of Ultrafine Cobalt Powder by Chemical Reduction in Aqueous Solution

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Nanocrystalline cobalt powders have been prepared from aqueous solution by reducing their corresponding metal salts under suitable conditions. The experimental conditions have been studied in detail. X-ray powder diffraction patterns show that the cobalt powder is hexagonal crystallite. The average particle size of the ultrafine cobalt powder is 55 nm.

  17. 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.

  18. 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.

  19. 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.

  20. Analysis of the Si(111) surface prepared in chemical vapor ambient for subsequent III-V heteroepitaxy

    Science.gov (United States)

    Zhao, W.; Steidl, M.; Paszuk, A.; Brückner, S.; Dobrich, A.; Supplie, O.; Kleinschmidt, P.; Hannappel, T.

    2017-01-01

    For well-defined heteroepitaxial growth of III-V epilayers on Si(111) substrates the atomic structure of the silicon surface is an essential element. Here, we study the preparation of the Si(111) surface in H2-based chemical vapor ambient as well as its atomic structure after contamination-free transfer to ultrahigh vacuum (UHV). Applying complementary UHV-based techniques, we derive a complete picture of the atomic surface structure and its chemical composition. X-ray photoelectron spectroscopy measurements after high-temperature annealing confirm a Si surface free of any traces of oxygen or other impurities. The annealing in H2 ambient leads to a monohydride surface termination, as verified by Fourier-transform infrared spectroscopy. Scanning tunneling microscopy confirms a well ordered, atomically smooth surface, which is (1 × 1) reconstructed, in agreement with low energy electron diffraction patterns. Atomic force microscopy reveals a significant influence of homoepitaxy and wet-chemical pretreatment on the surface morphology. Our findings show that wet-chemical pretreatment followed by high-temperature annealing leads to contamination-free, atomically flat Si(111) surfaces, which are ideally suited for subsequent III-V heteroepitaxy.

  1. 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.

  2. Preparation and analysis of chemically gradient functional bioceramic coating formed by pulsed laser deposition.

    Science.gov (United States)

    Rajesh, P; Muraleedharan, C V; Sureshbabu, S; Komath, Manoj; Varma, Harikrishna

    2012-02-01

    Bioactive ceramic coatings based on calcium phosphates yield better functionality in the human body for a variety of metallic implant devices including orthopaedic and dental prostheses. In the present study chemically and hence functionally gradient bioceramic coating was obtained by pulsed laser deposition method. Calcium phosphate bioactive ceramic coatings based on hydroxyapatite (HA) and tricalcium phosphate (TCP) were deposited over titanium substrate to produce gradation in physico-chemical characteristics and in vitro dissolution behaviour. Sintered targets of HA and α-TCP were deposited in a multi target laser deposition system. The obtained deposits were characterized by X-ray diffraction, fourier transform infrared spectroscopy, scanning electron microscopy and energy dispersive X-ray analysis. Inductively coupled plasma spectroscopy was used to estimate the in vitro dissolution behaviour of coatings. The variation in mechanical property of the gradient layer was evaluated through scratch test and micro-indentation hardness. The bioactivity was examined in vitro with respect to the ability of HA layer to form on the surface as a result of contact with simulated body fluid. It could be inferred that chemically gradient functional bioceramic coating can be produced by laser deposition of multiple sintered targets with variable chemical composition.

  3. Microwave-ultrasound combined reactor suitable for atmospheric sample preparation procedure of biological and chemical products

    NARCIS (Netherlands)

    Lagha, A.; Chemat, S.; Bartels, P.V.; Chemat, F.

    1999-01-01

    A compact apparatus in which a specific position can be irradiated by microwaves (MW) and ultrasound (US) simultaneously has been developed. The MW-US reactor has been designed for atmospheric pressure digestion and dissolution of biological and chemical products. The reactor can treat a range of th

  4. 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...

  5. High surface area activated carbon prepared from cassava peel by chemical activation.

    Science.gov (United States)

    Sudaryanto, Y; Hartono, S B; Irawaty, W; Hindarso, H; Ismadji, S

    2006-03-01

    Cassava is one of the most important commodities in Indonesia, an agricultural country. Cassava is one of the primary foods in our country and usually used for traditional food, cake, etc. Cassava peel is an agricultural waste from the food and starch processing industries. In this study, this solid waste was used as the precursor for activated carbon preparation. The preparation process consisted of potassium hydroxide impregnation at different impregnation ratio followed by carbonization at 450-750 degrees C for 1-3 h. The results revealed that activation time gives no significant effect on the pore structure of activated carbon produced, however, the pore characteristic of carbon changes significantly with impregnation ratio and carbonization temperature. The maximum surface area and pore volume were obtained at impregnation ratio 5:2 and carbonization temperature 750 degrees C.

  6. Preparing Federal Coordinating Officers (FCOs) to Operate in Chemical, Biological, Radiological, and Nuclear (CBRN) Environments

    Science.gov (United States)

    2008-12-01

    111 Rob Cross and Andrew Parker, The Hidden Power of Social Networks: Understanding How Work Really...167 Federal Emergency Management Agency, “FEMA Disaster Response Assets.” 168 John Conger , “Training and Planning Prepare the Joint Task...Clark, Kenneth. “Hurricane Ike After-Action Report.” Presentation given at the 14th FCO Retreat, Lansdowne, VA, November 3-7, 2008. Conger

  7. 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....

  8. The Adsorption Efficiency of Chemically Prepared Activated Carbon from Cola Nut Shells by on Methylene Blue

    OpenAIRE

    Julius Ndi Nsami; Joseph Ketcha Mbadcam

    2013-01-01

    The adsorption of methylene blue from aqueous solution onto activated carbon prepared from cola nut shell has been investigated under batch mode. The influence of major parameters governing the efficiency of the process such as, solution pH, sorbent dose, initial concentration, and contact time on the removal process was investigated. The time-dependent experimental studies showed that the adsorption quantity of methylene blue increases with initial concentration and decreasing adsorbent dosa...

  9. Effect of preparation conditions on physic-chemical properties of tin-doped nanocrystalline indium oxide

    Science.gov (United States)

    Malinovskaya, T. D.; Sachkov, V. I.; Zhek, V. V.; Nefedov, R. A.

    2016-01-01

    In this paper the results of investigation of phase formation and change of concentration of free electrons (Ne) in indium tin oxide system during heat treatment of coprecipitated hydroxides of indium and tin from nitric and hydrochloric solutions and also, for comparison melts of salts nitrates by an alkaline reactant (NH4OH) are considered.The performed investigation allowed to set the optimal condition of preparation of polycrystalline tin-doped indium oxide with maximal electron concentration.

  10. Preparation of Macroporous Epitaxial Quartz Films on Silicon by Chemical Solution Deposition.

    Science.gov (United States)

    Carretero-Genevrier, Adrián; Gich, Martí

    2015-12-21

    This work describes the detailed protocol for preparing piezoelectric macroporous epitaxial quartz films on silicon(100) substrates. This is a three-step process based on the preparation of a sol in a one-pot synthesis which is followed by the deposition of a gel film on Si(100) substrates by evaporation induced self-assembly using the dip-coating technique and ends with a thermal treatment of the material to induce the gel crystallization and the growth of the quartz film. The formation of a silica gel is based on the reaction of a tetraethyl orthosilicate and water, catalyzed by HCl, in ethanol. However, the solution contains two additional components that are essential for preparing mesoporous epitaxial quartz films from these silica gels dip-coated on Si. Alkaline earth ions, like Sr(2+) act as glass melting agents that facilitate the crystallization of silica and in combination with cetyl trimethylammonium bromide (CTAB) amphiphilic template form a phase separation responsible of the macroporosity of the films. The good matching between the quartz and silicon cell parameters is also essential in the stabilization of quartz over other SiO2 polymorphs and is at the origin of the epitaxial growth.

  11. 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.

  12. Preparation, characterisation and optimisation of lithium battery anodes consisting of silicon synthesised using Laser assisted Chemical Vapour Pyrolysis

    Science.gov (United States)

    Veliscek, Ziga; Perse, Lidija Slemenik; Dominko, Robert; Kelder, Erik; Gaberscek, Miran

    2015-01-01

    Suitability of silicon prepared using Laser assisted Chemical Vapour Pyrolysis (LaCVP) as a potential anode material in lithium batteries is systematically investigated. Its compositional, morphological, physical-chemical and electrochemical properties are compared to a current benchmark commercial silicon. Important differences in particle size and particle composition are found which, as shown, affect critically the rheological properties of the corresponding electrode slurries. In order to overcome the rheological problems of prepared nanosilicon, we introduce and optimise a spraying method instead of using the usual casting technique for slurry application. Interestingly, the optimised electrodes show similar electrochemical performance, regardless of the particle size or composition of nanosilicon. This unexpected result is explained by the unusually high resistance of electrochemical wiring in silicon-based electrodes (about 60 Ohm per 1 mg cm-2 of active material loading). Despite that, the optimised material still shows a capacity up to 1200 mA h g-1 at a relatively high loading of 1.6 mg cm-2 and after 20 cycles. On the other hand, by decreasing the loading to below ca. 0.9 mg cm-2 the wiring problems are effectively overcome and capacities close to theoretical values can be obtained.

  13. Food preparation characteristics of potato starch pastes containing a proportion of chemically-modified starch

    OpenAIRE

    菊地, 和美; 高橋 セツ子; 吉田 訓子; 山本 未穂; 知地 英征; Kazumi, KIKUCHI; Takahashi, Setsuko; Yoshida, Kuniko; Yamamoto, Miho; Chiji, Hideyuki; 藤女子大学人間生活学部食物栄養学科; 藤女子大学人間生活学部食物栄養学科藤女子大学大学院人間生活学研究科食物栄養学専攻

    2011-01-01

    Hokkaido potatoes are widely used as a source of starch. Potato starch is used for various purposes,particularly for the production of fish paste products,livestock products, and confectionery. Moreover, modified starch, which is produced by processing potato starch chemically and physically, is used in a variety of forms. This study examines the properties of modified starch gels produced by further enhancing the starch functions of potato starch. To study the primary properties of starch ge...

  14. 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.

  15. Textural and chemical characterization of activated carbon prepared from shell of african palm (Elaeis guineensis by chemical activation with CaCl2 and MgCl2

    Directory of Open Access Journals (Sweden)

    Sergio Acevedo

    2015-09-01

    Full Text Available Activated carbons through chemical activation of African palm shells (Elaeis guineensis with magnesium chloride and calcium chloride solutions at different concentrations were obtained. The prepared materials were characterized textural and chemically. The results show that activated carbons with higher values of surface area and pore volume are obtained when solutions with lower concentrations of the activating agent are used. The obtained activated carbons have surface areas and pore volumes with values between 10 and 501 m2 /g and 0.01 and 0.29 cm3 /g respectively. Immersion enthalpies values of solids in water were between -14.3 and -32.8 J/g and benzene between -13.9 and -38.6 J/g. Total acidity and basicity of the activated carbons had values between 23 and 262 μmol/g 123 and 1724 μmol/g respectively. pH at the point of zero charge was also determined with values between 4.08 and 9.92 for set of activated carbons . The results show that activation with CaCl2 and MgCl2 salts produce activated carbons with pores in the range of mesopores for facilitate entry of the adsorbate into the materials.

  16. Preparation of SmBiO3 buffer layer on YSZ substrate by an improved chemical solution deposition route

    Science.gov (United States)

    Zhu, Xiaolei; Pu, Minghua; Zhao, Yong

    2016-12-01

    A quick route for chemical solution deposition (CSD) has been developed to prepare SmBiO3 (SBO) layers on yttria stabilized zirconia (YSZ) substrates rapidly by using of solid state decomposition (SSD) technique. The proper conditions for volatilization of lactic acid, which as solvent in precursor coated layer, and SBO growth are 115°C for 30 min and 794°C for 60 min in flowing Ar gas. The coated layers are amorphous structure of mixture oxides and quasi-crystal structure of SBO before and after growth, respectively. The total time by this quick CSD route for organic solvent volatilization, salts decomposed and layer growth is not up to 2 h, which are much less than that needed for traditional CSD of over 10 h. SBO layer is directly epitaxial growth on YSZ substrate without any lattice rotation. SBO layer prepared by this quick route as well as that by traditional route are suitable for the growth of YBCO. The superconducting transition temperature and critical current density of the coated YBCO layer on SBO/YSZ obtained by this quick route are up to 90 K and 1.66 MA/cm2. These results may be the usable reference for continuous preparation of SBO buffer layer on IBAD-YSZ/Ni-based alloy tapes.

  17. Effect of growth time on Ti-doped ZnO nanorods prepared by low-temperature chemical bath deposition

    Science.gov (United States)

    Bidier, Shaker A.; Hashim, M. R.; Al-Diabat, Ahmad M.; Bououdina, M.

    2017-04-01

    Ti-doped ZnO nanorod arrays were grown onto Si substrate using chemical bath deposition (CBD) method at 93 °C. To investigate the effect of time deposition on the morphological, and structural properties, four Ti-doped ZnO samples were prepared at various deposition periods of time (2, 3.5, 5, and 6.5 h). FESEM images displayed high-quality and uniform nanorods with a mean length strongly dependent upon deposition time; i.e. it increases for prolonged growth time. Additionally, EFTEM images reveal a strong erosion on the lateral side for the sample prepared for 6.5 h as compared to 5 h. This might be attributed to the dissolution reaction of ZnO with for prolonged growth time. XRD analysis confirms the formation of a hexagonal wurtzite-type structure for all samples with a preferred growth orientation along the c-axis direction. The (100) peak intensity was enhanced and then quenched, which might be the result of an erosion on the lateral side of nanorods as seen in EFTEM. This study confirms the important role of growth time on the morphological features of Ti-doped ZnO nanorods prepared using CBD.

  18. TiO2:(Fe, S Thin Films Prepared from Complex Precursors by CVD, Physical Chemical Properties, and Photocatalysis

    Directory of Open Access Journals (Sweden)

    V. G. Bessergenev

    2012-01-01

    Full Text Available The TiO2 thin films were prepared using Ti(dpm2(OPri2 and Ti(OPri4 (dpm = 2,2,6,6-tetramethylheptane-3,5-dione, Pri = isopropyl as the precursors. The volatile compounds Fe[(C2H52NCS2]3 and [(CH3C]2S2 were used to prepare doped TiO2 films. The synthesis was done in vacuum or in the presence of Ar and O2. The pressure in the CVD chamber was varied between 1.2×10−4 mbar and 0.1 mbar, with the system working either in the molecular beam or gas flow regime. Physical, chemical, and photocatalytic properties of the (Fe, S-doped TiO2 films were studied. Those TiO2:(Fe, S films prepared from the Ti(OPri4 precursor show increased photocatalytic activities, very close to those of Degussa P25 powder in UV region.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. [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.

  7. 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.

  8. 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.

  9. Influence of formulation properties on chemical stability of captopril in aqueous preparations.

    Science.gov (United States)

    Kristensen, S; Lao, Y E; Brustugun, J; Braenden, J U

    2008-12-01

    The influence of various formulation properties on the chemical stability of captopril in aqueous media at pH 3 was investigated, in order to reformulate and increase the shelf-life of an oral mixture of the drug. At this pH, chemical stability is improved by an increase in drug concentration (1-5 mg/ml) and a decrease in temperature (5-36 degrees C), the latter demonstrated by a linear Arrhenius-plot. The activation energy is low (Ea = 10.2 kcal/mol), thus the Q10 value is only 1.8 in pure aqueous solutions. The degradation at the lowest concentration investigated in pure aqueous solution apparently follows zero order kinetics. The reaction order is changed at higher concentrations. We are presenting a hypothesis of intramolecular proton transfer from the thiol to the ionized carboxylic group as the initial step in the oxidative degradation pathways of captopril. Long-term stability of 1 mg/ml captopril in aqueous solutions at pH 3, stored at 36 degrees C for one year, shows that the sugar alcohol sorbitol accelerates degradation of the drug while Na-EDTA at a concentration as low as 0.01% is sufficient to stabilize these samples. Purging with N2-gas prior to storage is not essential for drug stability, as long as Na-EDTA is present. Only at a low level of Na-EDTA (0.01%) combined with a high level of sorbitol (35%), purging with N2-gas appears to have a small effect. The destabilizing effect of sugar alcohols is confirmed by accelerated degradation also in the presence of glycerol. The efficient stabilization in the presence of Na-EDTA at a low concentration indicates that the metal-ion-catalyzed oxidation pathway dominates the chemical degradation process at low pH, although several mechanisms seem to be involved depending on excipients present.

  10. Ion beam analysis of copper selenide thin films prepared by chemical bath deposition

    Science.gov (United States)

    Andrade, E.; García, V. M.; Nair, P. K.; Nair, M. T. S.; Zavala, E. P.; Huerta, L.; Rocha, M. F.

    2000-03-01

    Analyses of Rutherford back scattered (RBS) 4He+-particle spectra of copper selenide thin films deposited on glass slides by chemical bath were carried out to determine the changes brought about in the thin film by annealing processes. The atomic density per unit area and composition of the films were obtained from these measurements. This analysis shows that annealing in a nitrogen atmosphere at 400°C leads to the conversion of Cu xSe thin film to Cu 2Se. Results of X-ray diffraction, optical, and electrical characteristics on the films are presented to supplement the RBS results.

  11. 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.

  12. 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 physical and chemical......, particle size, a factor that has often been overlooked when dealing with amorphous materials, was shown to have an influence on physical stability of amorphous simvastatin....... 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...

  13. 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)

  14. Preparation of micro/nano-fibrous brushite coating on titanium via chemical conversion for biomedical applications

    Science.gov (United States)

    Liu, Bing; Guo, Yong-yuan; Xiao, Gui-yong; Lu, Yu-peng

    2017-03-01

    Calcium phosphate coatings have been applied on the surface of Ti implants to realize better osseointegration. The formation of dicalcium phosphate dihydrate (CaHPO4·2H2O), mineralogically named brushite on pure Ti substrate has been investigated via chemical conversion method. Coating composition and microstructure have been investigated by X-ray diffractometer, Fourier transform infrared spectrometer and field emission scanning electron microscope. The results reveal that the coatings are composed of high crystalline brushite with minor scholzite (CaZn2(PO4)2·2H2O). A micro/nano-scaled fibrous morphology can be produced in the acidic chemical conversion bath with pH 5.00. The surface of the fibrous brushite coating exhibits high hydrophilicity and corrosion resistance in the simulated body fluid. The osteoblast cells grow and spread actively on the coated samples and the proliferation numbers and alkaline phosphate activities of the cells improve significantly compared to the uncoated Ti. It is suggested that the micro/nano-fibrous brushite coating can be a potential approach to improve the osteoinductivity and osteoconductivity of Ti implant, due to its similarity in morphology and dimension to inorganic components of biological hard tissues, and favorable responses to the osteoblasts.

  15. Magnetic and magneto-optical properties of Co-P films prepared by chemical deposition

    Energy Technology Data Exchange (ETDEWEB)

    Chzhan, A.V., E-mail: avchz@mail.ru [Kirensky Institute of Physics, Russian Academy of Sciences, Siberian Branch, Krasnoyarsk 660036 (Russian Federation); Siberian Federal University, Krasnoyarsk 660041 (Russian Federation); Patrin, G.S. [Kirensky Institute of Physics, Russian Academy of Sciences, Siberian Branch, Krasnoyarsk 660036 (Russian Federation); Siberian Federal University, Krasnoyarsk 660041 (Russian Federation); Kiparisov, S.Ya.; Seredkin, V.A.; Burkova, L.V.; Velikanov, D.A. [Kirensky Institute of Physics, Russian Academy of Sciences, Siberian Branch, Krasnoyarsk 660036 (Russian Federation)

    2011-10-15

    Features in the formation of chemically deposited polycrystalline Co-P films with thicknesses of a few nanometers are established by analyzing film surface morphology and variation in the film magnetization. It is shown that in the thickness range below 30 nm the polar Kerr effect value {theta}{sub K} changes nonmonotonically and depends on a wavelength of the incident light. For the films thicker than 30 nm, this value depends weakly on both the thickness and the wavelength. These features in the {theta}{sub K} behavior are attributed to the Faraday effect, which is revealed at small thicknesses upon light reflection from the lower surface of a magnetic layer. It is found that the Faraday effect in the Co-P films exceeds that in the Co films by a factor of more than two. This effect is assumed to be caused by the presence of a Pd underlayer in the samples under study. - Highlights: > Chemically deposited Co-P films are investigated. > Features of the polar Kerr effect in these films with thickness from 1 to 50 nm are considered. > It is shown that the Faraday rotation angle in the Co-P films exceeds that in the Co films by a factor of two. > Hysteresis loops and magnetization values are presented.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. Methanol sensing by SnO2 pellets prepared by chemical route method

    Science.gov (United States)

    Choudhury, Sandip Paul; Kumari, Navnita; Bhattacharjee, Debanjan; Bhattacharjee, Ayon

    2016-05-01

    Synthesis of SnO2 and SnO2-CuO doped nanoparticles were carried out using chemical co-precipitation method. The precursor was SnCl4.5H2O. The XRD, SEM and EDAX of the nanoparticles were done, and the particle size was confirmed to be within 40nm. The powdered nanoparticles were then pelletized under a pressure of 13 Mp. Methanol was sensed with the pellets using a customized setup for 25, 50, 75 and 100ppm concentrations. It was observed that the sensitivity (S = Ra/Rg) showed appreciable variation at 375 °C and 275 °C for 75ppm and 100ppm of methanol respectively.

  2. Ethanol Sensing Properties of Nanosheets ZnO Thin Films Prepared by Chemical Bath Deposition

    Science.gov (United States)

    Julia, Sri; Nururddin, Ahmad; Nugraha, Suyatman; Yuliarto, Brian

    2011-12-01

    Nanosheets ZnO thin films were successfully fabricated on alumina substrate by chemical bath deposition method using Zinc Nitrate Tetra hydrate as precursor. Films were annealed at 300 °C for 30 minutes and observed by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy Dispersive X-Ray Spectroscopy (EDS) to know crystal phase and structure, surface morphology, and elemental composition respectively. The gas sensing performance of ZnO thin films was studied on exposure to ethanol gas sensing in various concentration (300 and 600 ppm). The films showed higher response towards ethanol gas sensing at optimized temperature of 250 °C and exhibited excellent sensitivity of 62.45% upon exposure 300 ppm and 69% upon exposure of 600 ppm ethanol gas sensing. Further, the response and recovery times of ZnO thin films to ethanol become shorter at higher operating temperatures. A possible mechanism of ethanol sensing has been explained.

  3. 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.

  4. 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.

  5. 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

  6. Guangzhou Chemical Industry%Preparation and Evaluation of Salvianolic Acid B Phospholipid Complex

    Institute of Scientific and Technical Information of China (English)

    李瑾; 朱美娟; 周凯; 王倩倩; 杨曼; 潘梓衡

    2016-01-01

    探讨了丹酚酸B磷脂复合物的制备最佳工艺条件。以丹酚酸B与磷脂的复合率为评价指标,考察反应溶剂、反应温度、反应时间、初始浓度和投料比对复合率的影响,采用正交实验筛选出最佳制备工艺,并通过差示扫描量热法、红外光谱、透射电镜以及泡沫细胞渗透性实验验证磷脂复合物形态及性质。确定丹酚酸B磷脂复合物制备的最佳工艺为:反应溶剂为四氢呋喃,反应温度40℃,反应时间3 h,丹酚酸B反应浓度为25 mg·mL-1,丹酚酸B与磷脂投料比为1:1,差示扫描量热法、红外光谱、透射电镜以及泡沫细胞渗透性等实验均证实了磷脂复合物的形成和优良特性。成功制备了丹酚酸B磷脂复合物,复合率可达99.5%。%To research the optimal conditions for preparing the SalB phospholipid complex, the formulation factors such as solvent, reactive temperature, reactive time, concentration of reactants and the ratio of reactants on this reaction were investigated and the prescription composition was screened out by orthogonal design. The morphologyand property of the phospholipid complex were verified by DSC, IR, TEMand form cell permeability experiment. The best conditions for preparing the SalB phospholipid complex were obtained as follows: the solvent was THF, the reactive temperature was 40 ℃, the reactive time was 3 h, the concentration of SalB was 25 mg·mL-1 and the ratio of SalB to phospholipid was 1:1. The recombination rate of SalB phospholipid complex were more than 99. 5%, and the quality of the SalB phospholipid complex was well.

  7. Structural and optical properties of Ni-doped CdS thin films prepared by chemical bath deposition method

    Energy Technology Data Exchange (ETDEWEB)

    Premarani, R. [Arumugam Pillai SeethaiAmmal College, Thiruppattur-630211 (India); Saravanakumar, S., E-mail: sarophy84@gmail.com; Chandramohan, R. [SreeSevuganAnnamalai College, Devakottai-630303 (India); Mahalingam, T. [Department of Electrical and Computer Engineering, Ajou University, Suwon 443-749 (Korea, Republic of)

    2015-06-24

    The structural and optical behavior of undoped Cadmiun Sulphide (CdS) and Ni-doped CdS thinfilms prepared by Chemical Bath Deposition (CBD) technique is reported. The crystallite sizes of the thinfilms have been characterized by X-ray diffraction pattern (XRD). The particle sizes increase with the increase of Ni content in the CdS thinfilms. Scanning Electron Microscope (SEM) results indicated that CdS thinfilms is made up of aggregate of spherical-like particles. The composition was estimated by Energy Dispersive Analysis of X-ray (EDX) and reported. Spectroscopic studies revealed considerable improvement in transmission and the band gap of the films changes with addition of Ni dopant that is associated with variation in crystallite sizes in the nano regime.

  8. Intertwisted fibrillar diamond-like carbon films prepared by electron cyclotron resonance microwave plasma enhanced chemical vapour deposition

    Institute of Scientific and Technical Information of China (English)

    杨武保; 王久丽; 张谷令; 范松华; 刘赤子; 杨思泽

    2003-01-01

    In this paper, the structures, optical and mechanical properties of diamond-like carbon films are studied, which are prepared by a self-fabricated electron cyclotron resonance microwave plasma chemical vapour deposition method at room temperature in the ambient gases of mixed acetylene and nitrogen. The morphology and microstructure of the processed film are characterized by the atomic force microscope image, Raman spectra and middle Fourier transform infrared transmittance spectra, which reveal that there is an intertwisted fibrillar diamond-like structure in the film and the film is mainly composed of sp3 CH, sp3 C-C, sp2 C=C, C=N and C60. The film micro-hardness and bulk modulus are measured by a nano-indenter and the refractive constant and deposition rate are also calculated.

  9. 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.

  10. 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.

  11. Architectured morphologies of chemically prepared NiO/MWCNTs nanohybrid thin films for high performance supercapacitors.

    Science.gov (United States)

    Gund, Girish S; Dubal, Deepak P; Shinde, Sujata S; Lokhande, Chandrakant D

    2014-03-12

    The preparation of nanostructured metal oxide decorated on multiwalled carbon nanotubes (MWCNTs) nanohybrid films through simple, scalable, additive-free, binderless, and cost-effective route has fascinated significant attention not only in fundamental research areas but also its commercial applications, in order to reduce the growing environmental pollution and the cost of electrode fabrication. Here, we report the fabrication of highly flexible electrode with NiO/MWCNTs nanohybrid thin films directly on stainless steel substrate using successive ionic layer adsorption and reaction (SILAR) method. The impact of ratio of adsorption and reaction cycles on structural, surface areas and electrochemical properties of NiO/MWCNTs nanohybrids was investigated. X-ray diffraction measurements confirm the hybridization and face centered cubic (FCC) crystal structure of NiO in NiO/MWCNTs nanohybrids. In addition, these nanohybrids exhibit excellent surface properties such as uniform surface morphology, good surface area, pore volume, and uniform pore size distribution. The electrochemical tests demonstrate the highest specific capacitance of 1727 F g(-1) at 5 mA cm(-2) of current density with 91% capacitance retention after 2000 cycles. In addition, the Ragone plot confirms the better power and energy densities for all NiO/MWCNTs nanohybrids. The attractive electrochemical capacitive activity revealed by NiO/MWCNTs nanohybrid electrode proposes that it is an auspicious respondent for future energy storage application.

  12. The Adsorption Efficiency of Chemically Prepared Activated Carbon from Cola Nut Shells by on Methylene Blue

    Directory of Open Access Journals (Sweden)

    Julius Ndi Nsami

    2013-01-01

    Full Text Available The adsorption of methylene blue from aqueous solution onto activated carbon prepared from cola nut shell has been investigated under batch mode. The influence of major parameters governing the efficiency of the process such as, solution pH, sorbent dose, initial concentration, and contact time on the removal process was investigated. The time-dependent experimental studies showed that the adsorption quantity of methylene blue increases with initial concentration and decreasing adsorbent dosage. The equilibrium time of 180 min was observed and maximum adsorption was favoured at pH 3.5. The dye removal using 0.1 g of adsorbent was more than 90%. This dosage (0.1 g was considered as the optimum dosage to remove methylene blue from aqueous solutions. The equilibrium adsorption data were analyzed by the Freundlich, Langmuir adsorption isotherm models. The kinetics of methylene blue solution was discussed by pseudo-first-order, pseudo-second-order, and Elovich models. The adsorption process follows the Elovich rate kinetic model, having a correlation coefficient in the range between 0.9811 and 1.

  13. 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.

  14. 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.

  15. 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.

  16. Physical and chemical properties and adsorption type of activated carbon prepared from plum kernels by NaOH activation.

    Science.gov (United States)

    Tseng, Ru-Ling

    2007-08-25

    Activated carbon was prepared from plum kernels by NaOH activation at six different NaOH/char ratios. The physical properties including the BET surface area, the total pore volume, the micropore ratio, the pore diameter, the burn-off, and the scanning electron microscope (SEM) observation as well as the chemical properties, namely elemental analysis and temperature programmed desorption (TPD), were measured. The results revealed a two-stage activation process: stage 1 activated carbons were obtained at NaOH/char ratios of 0-1, surface pyrolysis being the main reaction; stage 2 activated carbons were obtained at NaOH/char ratios of 2-4, etching and swelling being the main reactions. The physical properties of stage 2 activated carbons were similar, and specific area was from 1478 to 1887m(2)g(-1). The results of reaction mechanism of NaOH activation revealed that it was apparently because of the loss ratio of elements C, H, and O in the activated carbon, and the variations in the surface functional groups and the physical properties. The adsorption of the above activated carbons on phenol and three kinds of dyes (MB, BB1, and AB74) were used for an isotherm equilibrium adsorption study. The data fitted the Langmuir isotherm equation. Various kinds of adsorbents showed different adsorption types; separation factor (R(L)) was used to determine the level of favorability of the adsorption type. In this work, activated carbons prepared by NaOH activation were evaluated in terms of their physical properties, chemical properties, and adsorption type; and activated carbon PKN2 was found to have most application potential.

  17. Physical and chemical properties and adsorption type of activated carbon prepared from plum kernels by NaOH activation

    Energy Technology Data Exchange (ETDEWEB)

    Tseng, R.-L. [Department of Safety, Health and Environmental Engineering, National United University, Miao-Li 360, Taiwan (China)]. E-mail: trl@nuu.edu.tw

    2007-08-25

    Activated carbon was prepared from plum kernels by NaOH activation at six different NaOH/char ratios. The physical properties including the BET surface area, the total pore volume, the micropore ratio, the pore diameter, the burn-off, and the scanning electron microscope (SEM) observation as well as the chemical properties, namely elemental analysis and temperature programmed desorption (TPD), were measured. The results revealed a two-stage activation process: stage 1 activated carbons were obtained at NaOH/char ratios of 0-1, surface pyrolysis being the main reaction; stage 2 activated carbons were obtained at NaOH/char ratios of 2-4, etching and swelling being the main reactions. The physical properties of stage 2 activated carbons were similar, and specific area was from 1478 to 1887 m{sup 2} g{sup -1}. The results of reaction mechanism of NaOH activation revealed that it was apparently because of the loss ratio of elements C, H, and O in the activated carbon, and the variations in the surface functional groups and the physical properties. The adsorption of the above activated carbons on phenol and three kinds of dyes (MB, BB1, and AB74) were used for an isotherm equilibrium adsorption study. The data fitted the Langmuir isotherm equation. Various kinds of adsorbents showed different adsorption types; separation factor (R {sub L}) was used to determine the level of favorability of the adsorption type. In this work, activated carbons prepared by NaOH activation were evaluated in terms of their physical properties, chemical properties, and adsorption type; and activated carbon PKN2 was found to have most application potential.

  18. Synthesis mechanism of sono-chemically prepared mesoporous ZnS nanoparticles

    Science.gov (United States)

    Motejadded Emrooz, H. B.; Jalaly, M.

    2017-03-01

    The mechanism of sono-chemically synthesized mesoporous ZnS nanoparticles has been investigated. ZnS nanoparticles were synthesized with a facile and quick method. The sonication process was carried out for several times up to 60 min. The synthesized particles have been characterized with scanning electron microscopy, transmission electron microscopy, high resolution x-ray diffraction, UV–visible technique, diffuse reflectance spectroscopy, Brunauer–Emmett–Teller and Fourier transformation infrared spectroscopy. Based on x-ray diffraction patterns, crystallite size and lattice strain increase with sonication time. Adsorption–desorption results showed that applying the sono-chemistry synthesizing method in the aqueous atmosphere will cause a mesoporous structure. The obtained specific surface area of the synthesized mesoporous ZnS nanoparticles varied from 53 to 58 m2 · g‑1. Also the surface areas created from the porosity of the particles varied from 27 to 29 m2 · g‑1. Regarding these results, the mechanism of porosity formation during synthesis of nanoparticles has been explained. Photocatalytic behavior of the synthesized particles has been investigated for degradation of methylene blue from aqueous solution. Factors affecting this behavior have been discussed and it was found that interaction between opposing factors caused the specimen synthesized with 40 min sonication time has the best methylene blue degradation efficiency.

  19. Preparation of YBCO-BYTO and YBCO-BZO nanostructured superconducting films by chemical method

    Science.gov (United States)

    Garcés, P.; Coll, M.; Castro, H.; Puig, T.; Obradors, X.

    2017-01-01

    YBCO-BYTO6% and YBCO-BZO10% YBa2Cu3O7-d-Ba2YTaO6 6% (YBCO-BYTO6%) and YBa2Cu3O7--BaZrO3 10% (YBCO-BZO 10%) nanostructured films were grown by the Chemical Solution Deposition method, and compared with YBCO pure films. Films were deposited on YSZ substrates, with Ce0.9Zr0.1O2 and Ce0.6Zr0.4O2 buffer layers. They were characterized by GADDS X-ray diffraction, scanning electron microscopy (SEM) and inductive (SQUID) measurements of the critical temperature (Tc) and critical current density (Jc). It was found that YBCO-BZO10% films presented better superconducting properties (Tc=89.2K and Jc=1.3MA/cm2), probably due to an enhanced pinning force, originated by BZO nanoparticles. Additionally, it was found that these films have lower reactivity with the buffer layer.

  20. Preparation of D-gulose from disaccharide lactitol using microbial and chemical methods.

    Science.gov (United States)

    Morimoto, Kenji; Shimonishi, Tsuyoshi; Miyake, Seiki; Takata, Goro; Izumori, Ken

    2013-01-01

    When an M31 strain of Agrobacterium tumefaciens was grown in a mineral salt medium at 30 °C containing 1.0% lactitol as sole carbon source, a keto-sugar was efficiently accumulated in the supernatant. This oxidation from lactitol to the keto-sugar was caused by M31 cells grown with medium containing a disaccharide unit, including sucrose, lactitol, lactose, maltose, or maltitol, suggesting that the enzyme is inducible. M31 also demonstrated good growth characteristics in Tryptic Soy Broth (TSB) medium containing 1.0% sucrose, and cells grown under these conditions showed strong lactitol transformation activity. The keto-sugar product was reduced by chemical hydrogenation and the resulting product was hydrolyzed to D-gulose, D-galactose, and D-sorbitol by acid hydrolysis, revealing that the reduced products are lactitol and D-gulosyl-(β-1,4)-D-sorbitol. Taken together, these results indicate that M31 can convert lactitol to 3-ketolactitol and thus provide access to the rare sugar D-gulose.

  1. Preparation and characterization of boron nitride coatings on carbon fibers from borazine by chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Li Junsheng, E-mail: charlesljs@163.com [State Key Laboratory of Advanced Ceramic Fibers and Composites, College of Aerospace and Materials Engineering, National University of Defense Technology, Changsha, 410073 (China); Zhang Changrui; Li Bin [State Key Laboratory of Advanced Ceramic Fibers and Composites, College of Aerospace and Materials Engineering, National University of Defense Technology, Changsha, 410073 (China)

    2011-06-15

    Boron nitride (BN) coatings were deposited on carbon fibers by chemical vapor deposition (CVD) using borazine as single source precursor. The deposited coatings were characterized by scanning electron microscopy (SEM), Auger electron spectroscopy (AES), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. The effect of temperatures on growth kinetics, morphology, composition and structure of the coatings was investigated. In the low temperature range of 900 deg. C-1000 deg. C, the growth rate increased with increasing temperature complying with Arrhenius law, and an apparent active energy of 72 kJ/mol was calculated. The coating surface was smooth and compact, and the coatings uniformly deposited on individual fibers of carbon fiber bundles. The growth was controlled by surface reaction. At 1000 deg. C, the deposition rate reached a maximum (2.5 {mu}m/h). At the same time, the limiting step of the growth translated to be mass-transportation. Above 1100 deg. C, the growth rate decreased drastically due to the occurrence of gas-phase nucleation. Moreover, the coating surface became loose and rough. Composition and structure examinations revealed that stoichiometric BN coatings with turbostratic structure were obtained below 1000 deg. C, while hexagonal BN coatings were deposited above 1100 deg. C. A penetration of carbon element from the fibers to the coatings was observed.

  2. The challenge of preparation for a chemical, biological, radiological or nuclear terrorist attack

    Directory of Open Access Journals (Sweden)

    Alexander David

    2006-01-01

    Full Text Available Terrorism is not a new phenomenon, but, in the contemporary scene, it has established itself in a manner which commands the most serious attention of the authorities. Until relatively recently, the major threat has been through the medium of conventional weaponry and explosives. Their obvious convenience of use and accessibility guarantees that such methods will continue to represent a serious threat. However, over the last few years, terrorists have displayed an enthusiasm for higher levels of carnage, destruction and publicity. This trend leads inexorably to the conclusion that chemical, biological, radiological and nuclear (CBRN methods will be pursued by terrorist organisations, particularly those which are well organised, are based on immutable ideological principles, and have significant financial backing. Whilst it is important that the authorities and the general public do not risk over-reacting to such a threat (otherwise, they will do the work of the terrorists for them, it would be equally ill-advised to seek comfort in denial. The reality of a CBRN event has to be accepted and, as a consequence, the authorities need to consider (and take seriously how individuals and the community are likely to react thereto and to identify (and rehearse in a realistic climate what steps would need to be taken to ameliorate the effects of such an event.

  3. 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)

  4. Preparation and chemical characterization of neodymium-doped molybdenum oxide films grown using spray pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Alfonso, J. E. [Universidad Nacional de Colombia, Departamento de Fisica, Grupo de Ciencia Materiales y Superficies, AA 5997 Bogota DC (Colombia); Moreno, L. C., E-mail: jealfonsoo@unal.edu.co [Universidad Nacional de Colombia, Departamento de Quimica, AA 5997 Bogota DC (Colombia)

    2014-07-01

    We studied the crystalline, morphology, and surface composition of Nd-doped molybdenum oxide films grown on glass slides through spray pyrolysis. After fabrication, the films were subjected to thermal treatment in oxygen for periods ranging from 2 to 20 hours. The films were structurally characterized though X-ray diffraction (XRD), their bulk chemical composition was determined using Energy-Dispersive X-ray analysis (EDX), and their surface composition was determined using X-ray Photoelectron Spectroscopy (XP S). The XRD results show that the films obtained from different dissolution volumes and at substrate temperature of 300 grades C exhibit the characteristics of the oxygen-deficient molybdenum trioxide Mo{sub 9}O{sub 26} phase. The films subjected to different thermal treatments exhibit a mixture of Mo{sub 9}O{sub 26} and Mo{sub 17}O{sub 47} phases. EDX study shows the energy belonging to the L line of Nd. Finally, films doped with Nd and subjected to a thermal treatment of 20 h were analyzed through XP S, showing the binding energies at the crystalline lattice correspond to Nd{sub 2} (MoO{sub 4}){sub 3} and Nd{sub 2}Mo{sub 2}O{sub 7}. (Author)

  5. Chemical modification of magnetite nanoparticles and preparation of acrylic-base magnetic nanocomposite particles via miniemulsion polymerization

    Science.gov (United States)

    Mahdieh, Athar; Mahdavian, Ali Reza; Salehi-Mobarakeh, Hamid

    2017-03-01

    Nowadays, magnetic nanocomposite particles have attracted many interests because of their versatile applications. A new method for chemical modification of Fe3O4 nanoparticles with polymerizable groups is presented here. After synthesis of Fe3O4 nanoparticles by co-precipitation method, they were modified sequentially with 3-aminopropyl triethoxysilane (APTES), acryloyl chloride (AC) and benzoyl chloride (BC) and all were characterized by FTIR, XRD, SEM and TGA analyses. Then the modified magnetite nanoparticles with unsaturated acrylic groups were copolymerized with methyl methacrylate (MMA), butyl acrylate (BA) and acrylic acid (AA) through miniemulsion polymerization. Although several reports exist on preparation of magnetite-base polymer particles, but the efficiency of magnetite encapsulationwith reasonable content and obtaining final stable latexes with limited aggregation ofFe3O4 are still important issues. These were considered here by controlling reaction parameters. Hence, a seriesofmagneticnanocomposites latex particlescontaining different amounts of Fe3O4 nanoparticles (0-10 wt%) were prepared with core-shell morphology and diameter below 200 nm and were characterized by FT-IR, DSC and TGA analyses. Their morphology and size distribution were studied by SEM, TEM and DLS analyses too. Magnetic properties of all products were also measuredby VSM analysis and the results revealed almost superparamagnetic properties for the obtained nanocomposite particles.

  6. 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.

  7. Preparation, Characterization, and Size Control of Chemically Synthesized CdS Nanoparticles Capped with Poly(ethylene glycol)

    Science.gov (United States)

    Seoudi, R.; Allehyani, S. H. A.; Said, D. A.; Lashin, A. R.; Abouelsayed, A.

    2015-10-01

    We prepared cadmium sulfide (CdS) nanoparticles of a specific size via chemical precipitation at room temperature and characterized them using high-resolution transmission electron microscopy, x-ray powder diffraction, ultraviolet-visible spectroscopy, and Fourier-transform infrared (FTIR) measurements. The results showed that the samples were grown with a cubic phase; the particle size could be changed from 2 nm to 4 nm by varying the molar ratios of the precursors (cadmium chloride and sodium sulfide) in the presence of poly(ethylene glycol) (PEG) as an effective capping agent. The optical bandgap of the synthesized nanoparticles was calculated and ranged from 2.73 eV to 2.92 eV depending on the particle size. A large blue-shift from the bulk bandgap (2.42 eV) was observed owing to the quantum size effect. Surface passivation and adsorption of PEG on the CdS nanoparticles was explained on the basis of FTIR measurements; two bands were observed at 476 cm-1 and 622 cm-1, corresponding to cadmium and sulfide stretching vibrations. We conclude that particle size can be controlled by varying the molar ratios of the precursors. Owing to the PEG encapsulation, the as-prepared samples were extremely stable over time.

  8. 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.

  9. Characterization of mesoporous carbon prepared from date stems by H{sub 3}PO{sub 4} chemical activation

    Energy Technology Data Exchange (ETDEWEB)

    Hadoun, H., E-mail: hhadoun@hotmail.com [Nuclear Research Center, 2 Bd Frantz Fanon, Algiers (Algeria); Laboratory of Reaction Genius, Mechanical and Processes Genius Faculty, University of Sciences and Technology Houari – Boumediene, BP n°32, El alia, bab ezzouar, 16111 Algiers (Algeria); Sadaoui, Z. [Laboratory of Reaction Genius, Mechanical and Processes Genius Faculty, University of Sciences and Technology Houari – Boumediene, BP n°32, El alia, bab ezzouar, 16111 Algiers (Algeria); Souami, N.; Sahel, D.; Toumert, I. [Nuclear Research Center, 2 Bd Frantz Fanon, Algiers (Algeria)

    2013-09-01

    The present work was focused on the determination of texture, morphology, crystanillity and oxygenated surface groups characteristics of an activated carbon prepared from date stems. Chemical activation of this precursor at different temperatures (450, 550 and 650 °C) was adopted using phosphoric acid as dehydrating agent at (2/1) impregnation ratio. Fourier transform infrared spectroscopy study was carried out to identify surface groups in date stems activated carbons. The microscopic structure was examined by nitrogen adsorption at 77 K. The interlayer spacing (d{sub 200} and d{sub 100}), stack height (L{sub c}), stack width (L{sub a}) and effective dimension L of the turbostratic crystallites (microcrystallite) in the date stems activated carbons were estimated from X-ray diffraction data (XRD). Results yielded a surface area, S{sub BET}, and total pore volume of 682, 1455, 1319 m{sup 2}/g and 0,343, 1,045 and 0.735 cm{sup 3}/g, for the carbon prepared at 450, 550 and 650 °C, respectively. Scanning electron microscopy exhibits a highly developed porosity which is in good agreement with the porous texture derived from gas adsorption data and these results confirm that the activated carbon is dominated by network of slit-shaped mesopores morphology and in some cases by varied micropores morphologies.

  10. Preparation of rutile TiO(2) coating by thermal chemical vapor deposition for anticoking applications.

    Science.gov (United States)

    Tang, Shiyun; Wang, Jianli; Zhu, Quan; Chen, Yaoqiang; Li, Xiangyuan

    2014-10-08

    To inhibit the metal catalytic coking and improve the oxidation resistance of TiN coating, rutile TiO2 coating has been directly designed as an efficient anticoking coating for n-hexane pyrolysis. TiO2 coatings were prepared on the inner surface of SS304 tubes by a thermal CVD method under varied temperatures from 650 to 900 °C. The rutile TiO2 coating was obtained by annealing the as-deposited TiO2 coating, which is an alternative route for the deposition of rutile TiO2 coating. The morphology, elemental and phase composition of TiO2 coatings were characterized by SEM, EDX and XRD, respectively. The results show that deposition temperature of TiO2 coatings has a strong effect on the morphology and thickness of as-deposited TiO2 coatings. Fe, Cr and Ni at.% of the substrate gradually changes to 0 when the temperature is increased to 800 °C. The thickness of TiO2 coating is more than 6 μm and uniform by metalloscopy, and the films have a nonstoichiometric composition of Ti3O8 when the deposition temperature is above 800 °C. The anticoking tests show that the TiO2 coating at a deposition temperature of 800 °C is sufficiently thick to cover the cracks and gaps on the surface of blank substrate and cut off the catalytic coke growth effect of the metal substrate. The anticoking ratio of TiO2 coating corresponding to each 5 cm segments is above 65% and the average anticoking ratio of TiO2 coating is up to 76%. Thus, the TiO2 coating can provide a very good protective layer to prevent the substrate from severe coking efficiently.

  11. Physico-chemical properties of the new generation IV iron preparations ferumoxytol, iron isomaltoside 1000 and ferric carboxymaltose.

    Science.gov (United States)

    Neiser, Susann; Rentsch, Daniel; Dippon, Urs; Kappler, Andreas; Weidler, Peter G; Göttlicher, Jörg; Steininger, Ralph; Wilhelm, Maria; Braitsch, Michaela; Funk, Felix; Philipp, Erik; Burckhardt, Susanna

    2015-08-01

    The advantage of the new generation IV iron preparations ferric carboxymaltose (FCM), ferumoxytol (FMX), and iron isomaltoside 1000 (IIM) is that they can be administered in relatively high doses in a short period of time. We investigated the physico-chemical properties of these preparations and compared them with those of the older preparations iron sucrose (IS), sodium ferric gluconate (SFG), and low molecular weight iron dextran (LMWID). Mössbauer spectroscopy, X-ray diffraction, and Fe K-edge X-ray absorption near edge structure spectroscopy indicated akaganeite structures (β-FeOOH) for the cores of FCM, IIM and IS, and a maghemite (γ-Fe2O3) structure for that of FMX. Nuclear magnetic resonance studies confirmed the structure of the carbohydrate of FMX as a reduced, carboxymethylated, low molecular weight dextran, and that of IIM as a reduced Dextran 1000. Polarography yielded significantly different fingerprints of the investigated compounds. Reductive degradation kinetics of FMX was faster than that of FCM and IIM, which is in contrast to the high stability of FMX towards acid degradation. The labile iron content, i.e. the amount of iron that is only weakly bound in the polynuclear iron core, was assessed by a qualitative test that confirmed decreasing labile iron contents in the order SFG ≈ IS > LMWID ≥ FMX ≈ IIM ≈ FCM. The presented data are a step forward in the characterization of these non-biological complex drugs, which is a prerequisite to understand their cellular uptake mechanisms and the relationship between the structure and physiological safety as well as efficacy of these complexes.

  12. Preparation of porous, chemically cross-linked, PVdF-based gel polymer electrolytes for rechargeable lithium batteries

    Science.gov (United States)

    Cheng, C. L.; Wan, C. C.; Wang, Y. Y.

    This study reports the development of a new system of porous, chemically cross-linked, gel polymer electrolytes based on poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) copolymer as a polymer matrix, polyethylene glycol (PEG) as a plasticizer, and polyethylene glycol dimethacrylate (PEGDMA) as a chemical cross-linking oligomer. The electrolytes are prepared by a combination of controlled evaporation and thermal polymerization of PEGDMA. PVdF-HFP/PEG/PEGDMA gel polymer electrolytes with a composition of 5/3/2 exhibit both high ambient ionic conductivity, viz., >1 mS cm -1, and a high tensile modulus of 52 MPa, because of their porous and network structures. All the blends of electrolytes are electrochemically stable up to 5 V versus Li/Li + in the presence of 1 M LiPF 6/ethylene carbonate-diethyl carbonate (EC-DEC). With these polymer electrolytes, rechargeable lithium batteries composed of carbon anode and LiCoO 2 cathode have acceptable cycleability and a good rate capability.

  13. 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.

  14. Synthesis and characterization of graphene layers prepared by low-pressure chemical vapor deposition using triphenylphosphine as precursor

    Energy Technology Data Exchange (ETDEWEB)

    Mastrapa, G.C.; Maia da Costa, M.E.H. Maia [Departamento de Física, Pontifícia Universidade Católica do Rio de Janeiro, 22451-900, Rio de Janeiro, RJ (Brazil); Larrude, D.G., E-mail: dunigl@vdg.fis.puc-rio.br [Departamento de Física, Pontifícia Universidade Católica do Rio de Janeiro, 22451-900, Rio de Janeiro, RJ (Brazil); Freire, F.L. [Departamento de Física, Pontifícia Universidade Católica do Rio de Janeiro, 22451-900, Rio de Janeiro, RJ (Brazil); Brazilian Center for Physical Research, 22290-180, Rio de Janeiro, RJ (Brazil)

    2015-09-15

    The synthesis of a single-layer graphene using a low-pressure Chemical Vapor Deposition (CVD) system with triphenylphosphine as precursor is reported. The amount of triphenylphosphine used as precursor was in the range of 10–40 mg. Raman spectroscopy was employed to analyze samples prepared with 10 mg of the precursor, and these spectra were found typical of graphene. The Raman measurements indicate that the progressive degradation of graphene occurs as the amount of triphenylphosphine increases. X-ray photoelectron spectroscopy measurements were performed to investigate the different chemical environments involving carbon and phosphorous atoms. Scanning electron microscopy and transmission electron microscopy were also employed and the results reveal the formation of dispersed nanostructures on top of the graphene layer, In addition, the number of these nanostructures is directly related to the amount of precursor used for sample growth. - Highlights: • We grow graphene using the solid precursor triphenylphosphine. • Raman analysis confirms the presence of monolayer graphene. • SEM images show the presence of small dark areas dispersed on the graphene surface. • Raman I{sub D}/I{sub G} ratio increases in the dark region of the graphene surface.

  15. Chemical and Mechanical Evaluation of Bio-composites Based on Thermoplastic Starch and Wood Particles Prepared by Thermal Compression

    Directory of Open Access Journals (Sweden)

    María Guadalupe Lomelí-Ramírez

    2014-04-01

    Full Text Available The present work inspects the preparation of bio-composites of cassava starch with particles of eucalyptus wood through the application of a novel method of thermal compression. Bio-composites with different amounts of wood particles (5 to 30%, with particle sizes of 4 and 8 mm, were obtained. Chemical and mechanical evaluation of these samples was carried out using optical microscopy, infrared spectroscopy (FTIR, X-ray diffraction (XRD, scanning electron microscopy (SEM, and the moisture absorption effect. The effect of the amount and size of the wood particles was tested by comparison with a thermoplastic matrix sample. Results from these evaluations demonstrated that the thermo-compression method produced bio-composites with a distribution of particles in the matrix that contributed to an increase in their tensile strength. This mechanical property is also enhanced by interfacial adhesion between the matrix and particles, as confirmed by SEM. Furthermore, the maximum amount of particles in the bio-composites (30% showed the maximum resistance to moisture absorption. Temperature and time parameters contributed to the formation of diffraction patterns VH and EH as a consequence of the structural disruption of native starch. Finally, FTIR showed the chemical compatibility between the starch, glycerol, and wood particles.

  16. Preparation and Thermal Chemical Property of Complexes of Zinc Nitrate with Trytophan

    Institute of Scientific and Technical Information of China (English)

    陈三平; 高胜利; 杨旭武; 史启桢

    2003-01-01

    The solubility property of Zn(NO3)2-Tyr-H2O system at 25℃ in whole concentration range has been investigated by the semimicro phase equilibrium method.The corresponding phase diagrams and refractive index diagrams were constructed.Under the guidance of the phase equilibrium results,the incongruently soluble compounds of zn(Tyr)(NO3)2·2H2O(F) and Zn-(Try)2(NO3)2·H2O(G),which have not been reported previously,were synthesized and characterized by IR,XRD,TGDTG,as well as chemical and elemental analyses.The constant-volume combustion energies of the compounds,ΔcE,determined by a precision rotating bomb calorimeter at 298.15K,were (-13518.98±4.99)J·g-1 and (-17690.85±4.88)J·g-1,respectively.The standard enthalpies of combustion for these compounds,ΔcH, were calculated to be (-5802.36±2.14)kJ·mol-1 and (-10891.59±3.01)kJ·mol-1 when the standard enthalpies of formation,ΔfHm were (-1161.18±2.61)kJ·mol-1 and (-1829.71±4.20)kJ·mol-1.The enthalpies of solution in condition of simulating human gastricjuice(37℃,pH=1,the solution of hydrochloric acid),which were also measured by a microcalorimeter,were (14.55±0.04)kJ·mol-1 and (10.58±0.06)kJ·mol-1,respectively.

  17. Preparation and characteristics of chemical bath deposited ZnS thin films: Effects of different complexing agents

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Seung Wook [Department of Materials Science and Engineering, KAIST, Daejeon 305-701 (Korea, Republic of); Agawane, G.L.; Gang, Myeng Gil [Photonics Technology Research Institute, Department of Materials Science Engineering, Chonnam National University, Gwangju 500-757 (Korea, Republic of); Moholkar, A.V. [Department of Physics, Shivaji University, Kolhapur 416-004 (India); Moon, Jong-Ha [Photonics Technology Research Institute, Department of Materials Science Engineering, Chonnam National University, Gwangju 500-757 (Korea, Republic of); Kim, Jin Hyeok, E-mail: jinhyeok@chonnam.ac.kr [Photonics Technology Research Institute, Department of Materials Science Engineering, Chonnam National University, Gwangju 500-757 (Korea, Republic of); Lee, Jeong Yong, E-mail: j.y.lee@kaist.ac.kr [Department of Materials Science and Engineering, KAIST, Daejeon 305-701 (Korea, Republic of)

    2012-06-15

    Highlights: Black-Right-Pointing-Pointer Thick ZnS thin films were successfully prepared by chemical bath deposition in a basic medium using less toxic complexing agents. Black-Right-Pointing-Pointer Effect of different complexing agents such as no complexing agent, Na{sub 3}-citrate and a mixture of Na{sub 3}-citrate and EDTA on the properties of ZnS thin films was investigated. Black-Right-Pointing-Pointer ZnS thin film deposited using two complexing agent showed the outstanding characteristics as compared to those using no and one complexing agent. - Abstract: Zinc sulfide (ZnS) thin films were prepared on glass substrates by a chemical bath deposition technique using aqueous zinc acetate and thiourea solutions in a basic medium (pH {approx} 10) at 80 Degree-Sign C. The effects of different complexing agents, such as a non-complexing agent, Na{sub 3}-citrate, and a mixture of Na{sub 3}-citrate and ethylenediamine tetra-acetate (EDTA), on the structural, chemical, morphological, optical, and electrical properties of ZnS thin films were investigated. X-ray diffraction pattern showed that the ZnS thin film deposited without any complexing agent was grown on an amorphous phase. However, the ZnS thin films deposited with one or two complexing agents showed a polycrystalline hexagonal structure. No secondary phase (ZnO) was observed. X-ray photoelectron spectroscopy showed that all ZnS thin films exhibited both Zn-S and Zn-OH bindings. Field emission scanning electron microscopy (FE-SEM) images showed that ZnS thin films deposited with complexing agents had thicker thicknesses than that deposited without a complexing agent. The electrical resistivity of ZnS thin films was over 10{sup 5} {Omega} cm regardless of complexing agents. The average transmittance of the ZnS thin films deposited without a complexing agent, those with Na{sub 3}-citrate, and those with a mixture of Na{sub 3}-citrate and EDTA was approximately 85%, 65%, and 70%, respectively, while the band gap

  18. Controllable preparation of a nano-hydroxyapatite coating on carbon fibers by electrochemical deposition and chemical treatment.

    Science.gov (United States)

    Wang, Xudong; Zhao, Xueni; Wang, Wanying; Zhang, Jing; Zhang, Li; He, Fuzhen; Yang, Jianjun

    2016-06-01

    A nano-hydroxyapatite (HA) coating with appropriate thickness and morphology similar to that of human bone tissue was directly prepared onto the surfaces of carbon fibers (CFs). A mixed solution of nitric acid, hydrochloric acid, sulfuric acid, and hydrogen peroxide (NHSH) was used in the preparation process. The coating was fabricated by combining NHSH treatment and electrochemical deposition (ECD). NHSH treatment is easy to operate, produces rapid reaction, and highly effective. This method was first used to induce the nucleation and growth of HA crystals on the CF surfaces. Numerous O-containing functional groups, such as hydroxyl (-OH) and carboxyl (-COOH) groups, were grafted onto the CF surfaces by NHSH treatment (NHSH-CFs); as such, the amounts of these groups on the functionalized CFs increased by nearly 8- and 12-fold, respectively, compared with those on untreated CFs. After treatment, the NHSH-CFs not only acquired larger specific surface areas but retained surfaces free from serious corrosion or breakage. Hence, NHSH-CFs are ideal depositional substrates of HA coating during ECD. ECD was successfully used to prepare a nano-rod-like HA coating on the NHSH-CF surfaces. The elemental composition, structure, and morphology of the HA coating were effectively controlled by adjusting various technological parameters, such as the current density, deposition time, and temperature. The average central diameter of HA crystals and the coating density increased with increasing deposition time. The average central diameter of most HA crystals on the NHSH-CFs varied from approximately 60 nm to 210 nm as the deposition time increased from 60 min to 180 min. Further studies on a possible deposition mechanism revealed that numerous O-containing functional groups on the NHSH-CF surfaces could associate with electrolyte ions (Ca(2+)) to form special chemical bonds. These bonds can induce HA coating deposition and improve the interfacial bonding strength between the HA

  19. Photocatalytic, optical and magnetic properties of Fe-doped ZnO nanoparticles prepared by chemical route

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Khanesh; Chitkara, Mansi; Sandhu, Inderjit Singh [Nanomaterials Research Laboratory (NRL), Department of Applied Sciences, Chitkara University, Rajpura 140401, Punjab (India); Mehta, D. [Department of Physics, Panjab University, Chandigarh 160014 (India); Kumar, Sanjeev, E-mail: sanjeevkumar@chitkara.edu.in [Department of Physics, G.G.D.S.D. College, Chandigarh 160030 (India)

    2014-03-05

    Highlights: • Zn{sub 1-x}Fe{sub x}O nanoparticles are synthesized using bottom-up wet chemical precipitation technique. • Photocatalytic activity was evaluated by monitoring the photodegradation of methylene blue dye. • Specific magnetization values of the synthesized materials are found to depend on Fe concentration. -- Abstract: Polyvinyl pyrrolidone (PVP) capped Zn{sub 1−x}Fe{sub x}O (0.000001 ⩽ x ⩽ 0.1) nanocrystalline powders were prepared by chemical co-precipitation technique. Structural, optical and magnetic characterizations of the annealed samples were performed using X-ray powder diffraction (XRD), transmission electron microscope (TEM), energy dispersive X-ray fluorescence (EDXRF), Fourier-transform infrared (FTIR) spectroscopy, UV–visible spectrophotometry, photoluminescence (PL) and vibrating sample magnetometer (VSM) measurements. XRD and TEM studies reveal that the synthesized ZnO nanocrystals have hexagonal wurtzite structure with average crystalline size ∼8–15 nm. EDXRF and FTIR measurements confirmed the doping and incorporation of Fe impurities in ZnO nanostructures. Photocatalytic efficiency of the synthesized samples was determined by degradation of methylene blue (MB) dye in aqueous solution under UV/sunlight exposure. The dependence of photocatalytic behavior and luminescence efficiency on the dopant concentration was studied in detail. Magnetic measurements performed at room temperature show that pure ZnO exhibits diamagnetic behavior, ferromagnetic order was clearly observed at minute concentration of Fe impurity (at 0.000010%) and large concentration of dopant (at 10%) leads to strong paramagnetic component in all the Fe-doped ZnO samples.

  20. Fast and efficient adsorption of methylene green 5 on activated carbon prepared from new chemical activation method.

    Science.gov (United States)

    Tran, Hai Nguyen; You, Sheng-Jie; Chao, Huan-Ping

    2017-03-01

    Activated carbon (AC) was synthesized from golden shower (GS) through a new chemical activation process. The three-stage process comprised (1) hydrothermal carbonization of GS to produce hydrochar, (2) pyrolysis of hydrochar to produce biochar, and (3) subsequent chemical activation of biochar with K2CO3 to obtain GSHBAC. The traditional synthesis processes (i.e., one-stage and two-stage) were also examined for comparison. In the one-stage process, GS that was impregnated with K2CO3 was directly pyrolyzed (GSAC), and the two-stage process consisted of (1) pyrolytic or hydrothermal carbonization to produce biochar or hydrochar and (2) subsequent chemical activation was defined as GSBAC and GSHAC, respectively. The synthesized ACs were characterized by scanning electron microscope, Brunauer-Emmett-Teller (BET) surface area analysis, Fourier transform infrared spectrometry, point zero charge, and Boehm titration. The adsorption results demonstrated that the MG5 adsorption process was not remarkably affected by neither the solution pH (2.0-10) nor ionic strength (0-0.5 M NaCl). Kinetic studies showed that the adsorption equilibrium was quickly established, with a low activation energy required for adsorption (Ea; 3.30-27.8 kJ/mol), and the ACs removed 50-73% of the MG5 concentration from solution within 01 min. Desorption studies confirmed the adsorption was irreversible. Thermodynamic experiments suggested that the MG5 adsorption was spontaneous (-ΔG°) and endothermic (+ΔH°), and increased the randomness (+ΔS°) in the system. Although the specific surface areas of the ACs followed the order GSAC (1,413) > GSHAC (1,238) > GSHBAC (903) > GSBAC (812 m(2)/g), the maximum adsorption capacities determined from the Langmuir model (Q(o)max) at 30 °C exhibited the following order: GSHBAC (531) > GSAC (344) > GSHAC (332) > GSBAC (253 mg/g). Oxygenation of the ACs' surface through a hydrothermal process with acrylic acid resulted in a decrease in MG5

  1. 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.

  2. Structural and chemical characteristics of atomically smooth GaN surfaces prepared by abrasive-free polishing with Pt catalyst

    Science.gov (United States)

    Murata, Junji; Sadakuni, Shun; Okamoto, Takeshi; Hattori, Azusa N.; Yagi, Keita; Sano, Yasuhisa; Arima, Kenta; Yamauchi, Kazuto

    2012-06-01

    This paper reports the structural and chemical characteristics of atomically flat gallium nitride (GaN) surfaces prepared by abrasive-free polishing with platinum (Pt) catalyst. Atomic force microscopy revealed regularly alternating wide and narrow terraces with a step height equivalent to that of a single bilayer on the flattened GaN surfaces, which originate from the differences in etching rate of two neighboring terraces. The material removal characteristics of the method for GaN surfaces were investigated in detail. We confirmed that an atomically smooth GaN surface with an extremely small number of surface defects, including pits and scratches, can be achieved, regardless of the growth method, surface polarity, and doping concentration. X-ray photoelectron spectroscopy showed that the flattening method produces clean GaN surfaces with only trace impurities such as Ga oxide and metallic Ga. Contamination with the Pt catalyst was also evaluated using total-reflection X-ray fluorescence analysis. A wet cleaning method with aqua regia is proposed, which markedly eliminates this Pt contamination without affecting the surface morphology.

  3. Synthesis, Structural and Optoelectronic Properties of Nanocrystalline CdSe Thin Films Prepared By Chemical Bath Deposition Route

    Directory of Open Access Journals (Sweden)

    C. P. Nikam

    2015-12-01

    Full Text Available Cadmium Selenide (CdSe thin films were deposited onto glass substrates by simple and low cost chemical bath deposition (CBD technique. Aqueous ammonia was used as a complexing agent for the synthesis of these films. Deposition parameters were optimised and the crystal structure and morphology of the films were characterized by x-ray diffraction (XRD and field emission scanning electron microscopy (FE-SEM, respectively. XRD pattern revealed that the as-prepared CdSe thin films are polycrystalline with hexagonal structure. The average crystallite size of CdSe thin film was found to be in the range of 12-16 nm. FE-SEM image revealed that deposited thin films were consisting of nanocrystalline grains, which were coalesced to form bigger grains that are in cluster form distributed over the substrate surface. Transmission spectra showed high transmittance in the visible region and direct optical band gap energy was found to be a function of deposition time.

  4. 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.

  5. Thermal Shock Properties of a 2D-C/SiC Composite Prepared by Chemical Vapor Infiltration

    Science.gov (United States)

    Zhang, Chengyu; Wang, Xuanwei; Wang, Bo; Liu, Yongsheng; Han, Dong; Qiao, Shengru; Guo, Yong

    2013-06-01

    The thermal shock properties of a two-dimensional carbon fiber-reinforced silicon carbide composite with a multilayered self-healing coating (2D-C/SiC) were investigated in air. The composite was prepared by low-pressure chemical vapor infiltration. 2D-C/SiC specimens were thermally shocked for different cycles between 900 and 300 °C. The thermal shock resistance was characterized by residual tensile properties and mass variation. The change of the surface morphology and microstructural evolution of the composite were examined by a scanning electron microscope. In addition, the phase evolution on the surfaces was identified using an X-ray diffractometer. It is found that the composite retains its tensile strength within 20 thermal shock cycles. However, the modulus of 2D-C/SiC decreases gradually with increasing thermal shock cycles. Extensive pullout of fibers on the fractured surface and peeling off of the coating suggest that the damage caused by the thermal shock involves weakening of the bonding strength of coating/composite and fiber/matrix. In addition, the carbon fibers in the near-surface zone were oxidized through the matrix cracks, and the fiber/matrix interfaces delaminated when the composite was subjected to a larger number of thermal shock cycles.

  6. Facile preparation of graphene-copper nanoparticle composite by in situ chemical reduction for electrochemical sensing of carbohydrates.

    Science.gov (United States)

    Chen, Qiwen; Zhang, Luyan; Chen, Gang

    2012-01-03

    A novel graphene-copper nanoparticle composite was prepared by the in situ chemical reduction of a mixture containing graphene oxide and copper(II) ions using potassium borohydride as a reductant. It was mixed with paraffin oil and packed into one end of a fused capillary to fabricate microdisc electrodes for sensing carbohydrates. The morphology and structure of the graphene-copper nanoparticle composite were investigated by scanning electron microscopy, X-ray diffraction, and Fourier transform-infrared spectroscopy. The results indicated that copper nanoparticles with an average diameter of 20.8 nm were successfully deposited on graphene nanosheets to form a well interconnected hybrid network. The analytical performance of these unique graphene-copper nanoparticle composite paste electrodes was demonstrated by sensing five carbohydrates in combination with cyclic voltammetry and capillary electrophoresis (CE). The advantages of the composite detectors include higher sensitivity, satisfactory stability, surface renewability, bulk modification, and low expense of fabrication. They should find applications in microchip CE, flowing-injection analysis, and other microfluidic analysis systems.

  7. 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.

  8. Compositionally and structurally modified SrTiO{sub 3} thin films prepared by chemical solution deposition

    Energy Technology Data Exchange (ETDEWEB)

    Spitzner, Dirk; Gutmann, Emanuel; Reibold, Marianne; Meyer, Dirk C. [Institut fuer Strukturphysik, Technische Universitaet Dresden (Germany); Mahltig, Boris [GMBU e.V., Arbeitsgruppe Funktionelle Schichten, Dresden (Germany)

    2009-07-01

    For electronic and architectural design of functional electroceramic devices, materials with a perovskite-type of structure play a major role. For high-k dielectric, sensing and thermal switching applications the introduction of Barium into SrTiO{sub 3}(STO) allows tuning the electrical properties by tuning the paraelectric-to-ferroelectric transition temperature. For thin film preparation a classic sol-gel route was modified by refluxing as well as solvothermal treatment of the as-synthesized sols. For treated sols the decomposition, phase evolution and transition behaviour differed and from X-ray diffraction (XRD) we observed a supression of foreign phases and a higher degree of compositional homogeneity. In this context also the homologous series of perovskite-related Ruddlesden-Popper (RP) phases promise an engineering of electrical properties by selecting a specific member. Exemplarily we realised the chemical solution deposition of epitaxial thin films of SrO(SrTiO{sub 3}){sub n} RP phases (n=1,2,3) on STO substrates. Structural characteristics of the films were analysed by means of XRD and HRTEM. An application as buffer layers exhibiting tuneable dielectric properties is conceivable.

  9. 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

  10. 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

  11. 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

  12. 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.)

  13. 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.

  14. Testing REACH draft technical guidance notes for conducting chemical safety assessments-the experience of a downstream user of a preparation.

    Science.gov (United States)

    Gade, Anne Lill; Ovrebø, Steinar; Hylland, Ketil

    2008-07-01

    The goal of REACH is the safe use of chemicals. This study examines the efficiency and usefulness of two draft technical guidance notes in the REACH Interim Project 3.2-2 for the development of the chemical safety report and exposure scenarios. A case study was carried out for a paint system for protection of structural steel. The focuses of the study were risk assessment of preparations based on Derived No Effect Level (DNEL) and Predicted No Effect Concentrations (PNEC) and on effective and accurate communication in the supply chain. Exposure scenarios and generic descriptions of uses, risk management measures, and exposure determinants were developed. The study showed that communication formats, software tools, and guidelines for chemical risk assessment need further adjustment to preparations and real-life situations. Web platforms may simplify such communication. The downstream formulator needs basic substance data from the substance manufacturer during the pre-registration phase to develop exposure scenarios for preparations. Default values need to be communicated in the supply chain because these were critical for the derivation of applicable risk management demands. The current guidelines which rely on the available toxicological knowledge are insufficient to advise downstream users on how to develop exposure scenarios for preparations.

  15. SnS Thin Films Prepared by Chemical Spray Pyrolysis at Different Substrate Temperatures for Photovoltaic Applications

    Science.gov (United States)

    Sall, Thierno; Soucase, Bernabé Marí; Mollar, Miguel; Sans, Juan Angel

    2017-03-01

    The preparation and analysis of morphological, structural, optical, vibrational and compositional properties of tin monosulfide (SnS) thin films deposited on glass substrate by chemical spray pyrolysis is reported herein. The growth conditions were evaluated to reduce the presence of residual phases different to the SnS orthorhombic phase. X-ray diffraction spectra revealed the polycrystalline nature of the SnS films with orthorhombic structure and a preferential grain orientation along the (111) direction. At high substrate temperature (450°C), a crystalline phase corresponding to the Sn2S3 phase was observed. Raman spectroscopy confirmed the dominance of the SnS phase and the presence of an additional Sn2S3 phase. Scanning electron microscopy (SEM) images reveal that the SnS film morphology depends on the substrate temperature. Between 250°C and 350°C, SnS films were shaped as rounded grains with some cracks between them, while at substrate temperatures above 400°C, films were denser and more compact. Energy-dispersive x-ray spectroscopy (EDS) analysis showed that the stoichiometry of sprayed SnS films improved with the increase of substrate temperature and atomic force microscopy micrographs showed films well covered at 350°C resulting in a rougher and bigger grain size. Optical and electrical measurements showed that the optical bandgap and the resistivity decreased when the substrate temperature increased, and smaller values, 1.46 eV and 60 Ω cm, respectively, were attained at 450°C. These SnS thin films could be used as an absorber layer for the development of tandem solar cell devices due to their high absorbability in the visible region with optimum bandgap energy.

  16. Adhesion of fibroblasts on micro- and nanostructured surfaces prepared by chemical vapor deposition and pulsed laser treatment

    Energy Technology Data Exchange (ETDEWEB)

    Veith, M; Aktas, O C; Ullah Wazir, H; Grobelsek, I [INM-Leibniz Institute for New Materials, Campus D2 2, 66123 Saarbruecken (Germany); Metzger, W; Sossong, D; Pohlemann, T; Oberringer, M [Department of Trauma-, Hand- and Reconstructive Surgery, Saarland University, Kirrberger Strasse, Building 57, 66421 Homburg (Germany); Puetz, N; Wennemuth, G, E-mail: Michael.Veith@inm-gmbh.d [Department of Anatomy and Cell Biology, Saarland University, Kirrberger Strasse, Building 61, 66421 Homburg (Germany)

    2010-09-15

    The development of micro- and nanostructured surfaces which improve the cell-substrate interaction is of great interest in today's implant applications. In this regard, Al/Al{sub 2}O{sub 3} bi-phasic nanowires were synthesized by chemical vapor deposition of the molecular precursor ({sup t}BuOAlH{sub 2}){sub 2}. Heat treatment of such bi-phasic nanowires with short laser pulses leads to micro- and nanostructured Al{sub 2}O{sub 3} surfaces. Such surfaces were characterized by scanning electron microscopy (SEM), electron dispersive spectroscopy and x-ray photoelectron spectroscopy. Following the detailed material characterization, the prepared surfaces were tested for their cell compatibility using normal human dermal fibroblasts. While the cells cultivated on Al/Al{sub 2}O{sub 3} bi-phasic nanowires showed an unusual morphology, cells cultivated on nanowires treated with one and two laser pulses exhibited morphologies similar to those observed on the control substrate. The highest cell density was observed on surfaces treated with one laser pulse. The interaction of the cells with the nano- and microstructures was investigated by SEM analysis in detail. Laser treatment of Al/Al{sub 2}O{sub 3} bi-phasic nanowires is a fast and easy method to fabricate nano- and microstructured Al{sub 2}O{sub 3}-surfaces for studying cell-surface interactions. It is our goal to develop a biocompatible Al{sub 2}O{sub 3}-surface which could be used as a coating material for medical implants exhibiting a cell selective response because of its specific physical landscape and especially because it promotes the adhesion of osteoblasts while minimizing the adhesion of fibroblasts.

  17. 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).

  18. 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.

  19. Purely Chemical Approach for Preparation of d-α-Amino Acids via (S)-to-(R)-Interconversion of Unprotected Tailor-Made α-Amino Acids.

    Science.gov (United States)

    Nian, Yong; Wang, Jiang; Zhou, Shengbin; Dai, Wenhao; Wang, Shuni; Moriwaki, Hiroki; Kawashima, Aki; Soloshonok, Vadim A; Liu, Hong

    2016-05-06

    Unnatural (R)-α-amino acids (α-AAs) are in growing demand in the biomedical research and pharmaceutical industries. In this work, we present development of a purely chemical approach for preparation of (R)-α-AAs via (S)-to-(R)-interconversion of natural and tailor-made (S)-α-AAs. The method can be used on free, unprotected α-AAs and features a remarkable structural generality including substrates bearing tertiary alkyl chains and reactive functional groups. These attractive characteristics, combined with simplicity of reaction conditions and virtually complete stereochemical outcome, constitute a true methodological advance in this area, rivaling previously reported chemical and biocatalytic approaches.

  20. Scanning transmission electron microscope analysis of amorphous-Si insertion layers prepared by catalytic chemical vapor deposition, causing low surface recombination velocities on crystalline silicon wafers

    OpenAIRE

    2012-01-01

    Microstructures of stacked silicon-nitride/amorphous-silicon/crystalline-silicon (SiN_x/a-Si/c-Si) layers prepared by catalytic chemical vapor deposition were investigated with scanning transmission electron microscopy to clarify the origin of the sensitive dependence of surface recombination velocities (SRVs) of the stacked structure on the thickness of the a-Si layer. Stacked structures with a-Si layers with thicknesses greater than 10 nm exhibit long effective carrier lifetimes, while thos...

  1. 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.

  2. 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.

  3. 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,…

  4. Preparation and chemical and biological characterization of a pectin/chitosan polyelectrolyte complex scaffold for possible bone tissue engineering applications.

    Science.gov (United States)

    Coimbra, P; Ferreira, P; de Sousa, H C; Batista, P; Rodrigues, M A; Correia, I J; Gil, M H

    2011-01-01

    In this work, porous scaffolds obtained from the freeze-drying of pectin/chitosan polyelectrolyte complexes were prepared and characterized by FTIR, SEM and weight loss studies. Additionally, the cytotoxicity of the prepared scaffolds was evaluated in vitro, using human osteoblast cells. The results obtained showed that cells adhered to scaffolds and proliferated. The study also confirmed that the degradation by-products of pectin/chitosan scaffold are noncytotoxic.

  5. 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...

  6. Ni nanoparticles prepared by simple chemical method for the synthesis of Ni/NiO-multi-layered graphene by chemical vapor deposition

    Science.gov (United States)

    Ali, Mokhtar; Remalli, Nagarjuna; Gedela, Venkataramana; Padya, Balaji; Jain, Pawan Kumar; Al-Fatesh, Ahmed; Rana, Usman Ali; Srikanth, Vadali V. S. S.

    2017-02-01

    A new chemical method was used to obtain a high yield of nickel nanoparticles (Ni-NPs). The effect of solvent (distilled water, ethylene glycol, and ethanol) and surfactant (oleic acid and polyvinyl pyrrolidinone) on the morphology and crystallinity of the synthesized Ni-NPs has been investigated. The experimental results revealed that among the solvents mentioned above, ethanol gives the best results in terms of complete reduction, controlled morphology and size distribution of Ni-NPs. The surfactants played an important role in impeding the agglomeration and surface oxidation of Ni-NPs. The surfactants also affected the morphology of the Ni-NPs. The synthesized Ni-NPs are found to be quite stable in air. The best of the synthesized Ni-NPs were effectively used as catalysts for the synthesis of Ni/NiO-multi-layered graphene using catalytic chemical vapor deposition technique.

  7. 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.

  8. 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.

  9. High-throughput analysis for preparation, processing and analysis of TiO{sub 2} coatings on steel by chemical solution deposition

    Energy Technology Data Exchange (ETDEWEB)

    Cuadrado Gil, Marcos, E-mail: Marcos.cuadradogil@ugent.be [SCRIPTS - Department of Inorganic and Physical Chemistry, Ghent University, Krijgslaan 281 (S3) (Belgium); Van Driessche, Isabel, E-mail: Isabel.VanDriessche@ugent.be [SCRIPTS - Department of Inorganic and Physical Chemistry, Ghent University, Krijgslaan 281 (S3) (Belgium); Van Gils, Sake, E-mail: Sake.Vangils@arcelormittal.com [OCAS - ArcelorMittal Gent R and D Centre, Pres. J.F. Kennedylaan 3, Zelzate B-9060 (Belgium); Lommens, Petra, E-mail: Petra.Lommens@ugent.be [SCRIPTS - Department of Inorganic and Physical Chemistry, Ghent University, Krijgslaan 281 (S3) (Belgium); Castelein, Pieter, E-mail: Pieter.Castelein@flamac.be [Flamac - A Division of SIM, Technologiepark 903, Zwijnaarde 9052 (Belgium); De Buysser, Klaartje, E-mail: Klaartje.DeBuysser@ugent.be [SCRIPTS - Department of Inorganic and Physical Chemistry, Ghent University, Krijgslaan 281 (S3) (Belgium)

    2012-11-05

    Highlights: Black-Right-Pointing-Pointer High-throughput preparation of TiO{sub 2} aqueous precursors. Black-Right-Pointing-Pointer Analysis of stability and surface tension. Black-Right-Pointing-Pointer Deposition of TiO{sub 2} coatings. - Abstract: A high-throughput preparation, processing and analysis of titania coatings prepared by chemical solution deposition from water-based precursors at low temperature ( Almost-Equal-To 250 Degree-Sign C) on two different types of steel substrates (Aluzinc Registered-Sign and bright annealed) is presented. The use of the high-throughput equipment allows fast preparation of multiple samples saving time, energy and material; and helps to test the scalability of the process. The process itself includes the use of IR curing for aqueous ceramic precursors and possibilities of using UV irradiation before the final sintering step. The IR curing method permits a much faster curing step compared to normal high temperature treatments in traditional convection devices (i.e., tube furnaces). The formulations, also prepared by high-throughput equipment, are found to be stable in the operational pH range of the substrates (6.5-8.5). Titanium alkoxides itself lack stability in pure water-based environments, but the presence of the different organic complexing agents prevents it from hydrolysis and precipitation reactions. The wetting interaction between the substrates and the various formulations is studied by the determination of the surface free energy of the substrates and the polar and dispersive components of the surface tension of the solutions. The mild temperature program used for preparation of the coatings however does not lead to the formation of pure crystalline material, necessary for the desired photocatalytic and super-hydrophilic behavior of these coatings. Nevertheless, some activity can be reported for these amorphous coatings by monitoring the discoloration of methylene blue in water under UV irradiation.

  10. 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.

  11. 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.

  12. 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.

  13. Fabrication of solar cells based on Cu2ZnSnS4 prepared from Cu2SnS3 synthesized using a novel chemical procedure

    Directory of Open Access Journals (Sweden)

    Correa John M.

    2016-01-01

    Full Text Available Solar cells based on kesterite-type Cu2ZnSnS4 (CZTS thin films were fabricated using a chemical route to prepare the CZTS films, consisting in sequential deposition of Cu2SnS3 (CTS and ZnS thin films followed by annealing at 550 °C in nitrogen atmosphere. The CTS compound was prepared in a one-step process using a novel chemical procedure consisting of simultaneous precipitation of Cu2S and SnS2 performed by diffusion membranes assisted CBD (chemical bath deposition technique. Diffusion membranes were used to optimize the kinetic growth through a moderate control of release of metal ions into the work solution. As the conditions for the formation in one step of the Cu2SnS3 compound have not yet been reported in literature, special emphasis was put on finding the parameters that allow growing the Cu2SnS3 thin films by simultaneous precipitation of Cu2S and SnS2. For that, we propose a methodology that includes numerical solution of the equilibrium equations that were established through a study of the chemical equilibrium of the system SnCl2, Na3C6H5O7·2H2O, CuCl2 and Na2S2O3·5H2O. The formation of thin films of CTS and CZTS free of secondary phases grown with a stoichiometry close to that corresponding to the Cu2SnS3 and Cu2ZnSnS4 phases, was verified through measurements of X-ray diffraction (XRD and Raman spectroscopy. Solar cell with an efficiency of 4.2%, short circuit current of 16.2 mA/cm2 and open-circuit voltage of 0.49 V was obtained.

  14. 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

  15. Synthesis of dendron-protected porphyrin wires and preparation of a one-dimensional assembly of gold nanoparticles chemically linked to the pi-conjugated wires.

    Science.gov (United States)

    Ozawa, Hiroaki; Kawao, Masahiro; Tanaka, Hirofumi; Ogawa, Takuji

    2007-05-22

    A one-dimensional assembly of gold nanoparticles chemically bonded to pi-conjugated porphyrin polymers was prepared on a chemically modified glass surface and on an undoped naturally oxidized silicon surface by the following methods: pi-conjugated porphyrin polymers were prepared by oxidative coupling of 5,15-diethynyl-10,20-bis-((4-dendron)phenyl) porphyrin (6), and its homologues (larger than 40-mer) were collected by analytical gel permeation chromatography (GPC). The porphyrin polymers (>40-mer) were deposited using the Langmuir-Blodgett (LB) method on substrate surfaces, which were then soaked in a solution of gold nanoparticles (2.7 +/- 0.8 nm) protected with t-dodecanethiol and 4-pyridineethanethiol. The topographical images of the surface observed by tapping mode atomic force microscopy (AFM) showed that the polymers could be dispersed on both substrates, with a height of 2.8 +/- 0.5 nm on the modified glass and 3.1 +/- 0.5 nm on silicon. The height clearly increased after soaking in the gold nanoparticle solution, to 5.3 +/- 0.5 nm on glass and 5.4 +/- 0.7 nm on silicon. The differences in height (2.5 nm on glass and 2.3 nm on silicon) corresponded to the diameter of the gold nanoparticles bonded to the porphyrin polymers. The distance between gold nanoparticles observed in scanning electron microscopic images was ca. 5 nm, indicating that they were bonded at every four or five porphyrin units.

  16. The atomic structure and chemical composition of HfOx (x < 2) films prepared by ion-beam sputtering deposition

    Science.gov (United States)

    Aliev, V. S.; Gerasimova, A. K.; Kruchinin, V. N.; Gritsenko, V. A.; Prosvirin, I. P.; Badmaeva, I. A.

    2016-08-01

    Non-stoichiometric HfOx films of different chemical composition (x partial pressure in a chamber. An effect of chemical composition on the atomic structure of the films was studied by reflection high-energy electron diffraction, x-ray photoelectron spectroscopy and field emission scanning electron microscopy methods. The films were found to be amorphous, consisting only of three components: Hf-metal clusters, Hf4O7 suboxide and stoichiometric HfO2. The relative concentration of these components varies with changing x. The surface of the films contains the increased oxygen content compared to the bulk. It was found that the Hf4O7 suboxide concentration is maximal at x = 1.8. The concept of hafnium oxide film growth by the IBSD method is proposed to explain the lack of suboxides variety in the films and the instability of HfO2, when annealed at high temperature.

  17. 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...

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

    OpenAIRE

    2013-01-01

    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 ...

  19. 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.

  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)

    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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. Preparation of DNA-adsorbed TiO2 particles with high performance for purification of chemical pollutants.

    Science.gov (United States)

    Suzuki, Hiroshi; Amano, Takeharu; Toyooka, Tatsushi; Ibuki, Yuko

    2008-11-01

    Photocatalysis using semiconductors such as titanium dioxide (TiO2) has been studied and applied to the treatment of wastewater and purification of air, because of its ability to decompose organic contaminants. However, there are still problems associated with the practical application of photocatalytic reactions, one of which is that contact between the reactants and catalysts is absolutely required, because the reaction occurs atthe surface of the catalysts. This restrictsthe purification of pollutants on a large scale. In this study, we developed novel DNA-adsorbed TiO2 particles (DNA-TiO2) to solve the problem. Because DNA has an unique double-stranded structure and interacts with several chemicals, DNA-TiO2 can accumulate chemicals on the surface of TiO2. DNA intercalators (Methylene Blue and ethidium bromide), small amounts of which exist in large-volume solutions, were instantaneously trapped in DNA-TiO2 and degraded under ultraviolet (UV) light rapidly, compared to nonadsorbed TiO2. The efficiency of removal and photocatalytic degradation was dependent on the amount of DNA adsorbed on the surface of TiO2 and was independent of the size of DNA. Even if the pH (2-10) and temperature (approximately 56 degrees C) of the solution were changed, DNA remained stable on TiO2, and the ability to remove intercalators was also maintained. DNA-TiO2 could accumulate other pigments such as Acridine Orange, Orange II, Neutral Red, Brilliant Green, and Crystal Violet. These results suggested that DNA-TiO2 is beneficial for the removal and degradation of chemicals having affinity for DNA and dispersing in a large field.

  6. Changes in chemical composition and nanostructure of SiC thin films prepared by PECVD during thermal annealing

    Energy Technology Data Exchange (ETDEWEB)

    Kuenle, Matthias; Janz, Stefan [Fraunhofer Institute of Solar Energy Systems ISE, Heidenhofstr. 2, 79110 Freiburg (Germany); Nickel, Klaus Georg [Applied Mineralogy, Institute for Geosciences, Eberhard-Karl-University Tuebingen, Wilhelmstr. 52, 72074 Tuebingen (Germany); Eibl, Oliver [Institute for Applied Physics, Eberhard-Karls-University Tuebingen, Auf der Morgenstelle 10, 72074 Tuebingen (Germany)

    2011-08-15

    Silicon carbide (SiC) thin films were deposited on silicon (Si) using plasma enhanced chemical vapor deposition (PECVD). Annealing was done in a rapid thermal annealing furnace at a temperature of 1300 C. As-deposited and annealed Si-rich and stoichiometric SiC thin films were investigated by analytical transmission electron microscopy (AEM). TEM-energy-dispersive X-ray spectroscopy was used to quantify the chemical composition of the SiC thin films with high accuracy. The chemical composition of the near stoichiometric SiC thin film changed during annealing from Si{sub 0.4}C{sub 0.6} to Si{sub 0.5}C{sub 0.5} due to diffusion of Si from the Si substrate into the film. The Si-rich Si{sub 1-x}C{sub x} film had the identical chemical composition of Si{sub 0.8}C{sub 0.2} before and after annealing. As-deposited films show nanoporosity within the bulk film. During annealing, v-shaped defect structures were formed at the interface of the stoichiometric SiC thin film to the Si substrate. Diffraction patterns revealed that as-deposited films were amorphous. During annealing the crystallization of 3C-SiC occurred in near-stoichiometric SiC thin films, whereas in Si-rich Si{sub 1-x}C{sub x} thin films two phases, namely Si and 3C-SiC, crystallized. Low-loss and core-loss electron energy loss spectroscopy (EELS) verified the diffraction results. In the low-loss spectra of the near stoichiometric SiC thin film, a plasmon peak located at 20.2 eV before and at 22.3 eV after annealing was detected. The low-loss spectra of the Si-rich Si{sub 1-x}C{sub x} thin film showed an asymmetric plasmon peak with two maxima located at 18.5 and 25.0 eV in the as-deposited film and 18.6 and 24.3 eV in the annealed Si-rich Si{sub 1-x}C{sub x} film. The 18.5 eV plasmon peaks is assigned to Si and the 25 eV plasmon peak is attributed to the SiC phase. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  7. Preparation of nano-crystalline cellulose by chemical methods%化学法制备纳米微晶纤维素的研究进展

    Institute of Scientific and Technical Information of China (English)

    李媛媛; 戴红旗

    2012-01-01

    纳米微晶纤维素是一种制备原料来源广泛、成本低、在功能材料等领域有广泛应用前景的可再生新兴纤维素功能材料.然而纳米微晶纤维素的制备存在得率低、水耗大、对设备要求严格等缺点,限制了纳米微晶纤维素的大规模生产;因此寻找纳米微晶纤维素的绿色、高效制备方法显得尤为重要.笔者从原料和化学制备方法上综述了制备纳米微晶纤维素的研究进展,并对纳米微晶纤维素制备及纳米微晶纤维素基功能材料的进一步发展应用进行了展望.%Nano-crystalline cellulose is a renewable functional cellulose material with great application value in functional material and other fields. It can be obtained from a variety of sources at a low cost. However, there are many drawbacks such as low yield, huge water consumption as well as strict requirement on equipment in the preparation which limit the nanocrystalline cellulose from mass production. The isolation of nanocrystalline cellulose from cellulose fibers u-sing a green and effective method is a great challenge. In this paper, the development of nanocrystalline cellulose preparation was summarized from the aspects of raw materials to chemical preparation methods. In addition, further application and development in nanocrystalline cellulose preparation and nanocrystalline cellulose based functional materials were discussed.

  8. Preparation and testing of a solid secondary plasticizer for PVC produced by chemical degradation of post-consumer PET.

    Science.gov (United States)

    Amaro, Lucía Pérez; Coiai, Serena; Ciardelli, Francesco; Passaglia, Elisa

    2015-12-01

    Post-consumer poly(ethylene therephthalate) (PET) obtained from milled water bottles was chemically degraded by glycolysis, using suitable amounts of diethylene glycol (DEG) and Ca/Zn stearate as catalyst system. The process was carried out by employing a melt mixer as the chemical reactor, which is the facility generally used for plastic compounding. The degraded PET products were first characterized from structural and thermal point of view by Fourier transform infrared spectroscopy (FTIR), Proton nuclear magnetic resonance ((1)H NMR), Size exclusion chromatography (SEC) Differential scanning calorimetry (DSC) and Thermogravimetric analysis (TGA), and thereafter used alone or together with di(2-ethylhexyl) phthalate (DEHP) in poly(vinyl chloride) PVC formulations. The plasticization was, in fact, accomplished by using a binary system consisting of DEHP as primary plasticizer and a degraded PET product as secondary plasticizer (SP). The obtained materials were characterized through the main methods used to assess flexible PVC compounds: hardness in Shore A scale, thermal properties and quantitative migration of the plasticizer. The solid secondary plasticizer obtained from post-consumer PET improves both the processing characteristics and the thermal stability of the final flexible PVC compounds while maintaining their hardness within the top values of the Shore A scale. In addition, a considerable reduction of the plasticizers migration (23%) was obtained by optimizing the formulation.

  9. 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.

  10. Improving the productivity of a multidimensional chromatographic preparative system by collecting pure chemicals after each of three chromatographic dimensions.

    Science.gov (United States)

    Sciarrone, Danilo; Pantò, Sebastiano; Donato, Paola; Mondello, Luigi

    2016-12-02

    The enhanced sample collection capability of a heart-cutting three-dimensional GC-prep system is reported. In its original configuration, a highly pure component can be usually collected after the last (3D) column outlet by means of a dedicated preparative station. The latter is located after the last chromatographic column, and this poses the requirement for multiple heart cuts even for those components showing satisfactory degree of purity after the first (or second) separation dimension. The feasibility to collect pure components after each chromatographic dimension is here described, employing a three-dimension MDGC system equipped with high-temperature valves, located inside the first and second GC ovens, with the aim to improve the productivity of the collection procedure. In addition to a commercial preparative collector located at the 3D outlet, two laboratory-made collection systems were applied in the first and second dimension, reached by the effluent to be collected trough a high-temperature valve switching the heart-cut fraction between either the detector (FID), or the collector. Highly pure sesquiterpene components were collected, namely: patchouli alcohol after the first column [poly(5% diphenyl/95% dimethylsiloxane)], α-bulnesene after a second column coated with high molecular weight polyethylene glycol, and α-guaiene after an ionic-liquid based column (SLB-IL60), used as the third dimension. Purity levels ranging from 85 to 95% were achieved with an average collection recovery of 90% (n=5). The following average amounts were collected per run: 160μg for α-guaiene, 295μg for α-bulnesene, and 496μg for patchouli alcohol.

  11. 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.)

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

    Science.gov (United States)

    Zhu, Min; Zhu, Yufang; Zhang, Lingxia; Shi, Jianlin

    2013-08-01

    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. 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.

  14. 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.

  15. Effect of counterpart metals in carbon-supported Pt-based catalysts prepared using radiation chemical method

    Science.gov (United States)

    Okazaki, Tomohisa; Seino, Satoshi; Matsuura, Yoshiyuki; Otake, Hiroaki; Kugai, Junichiro; Ohkubo, Yuji; Nitani, Hiroaki; Nakagawa, Takashi; Yamamoto, Takao A.

    2017-04-01

    The process of nanoparticle formation by radiation chemical synthesis in a heterogeneous system has been investigated. Carbon-supported Pt-based bimetallic nanoparticles were synthesized using a high-energy electron beam. Rh, Cu, Ru, and Sn were used as counterpart metals. The nanoparticles were characterized by inductively coupled plasma atomic emission spectrometry, transmission electron microscopy, X-ray diffraction, and X-ray absorption spectroscopy. PtRh formed a uniform random alloy nanoparticle, while Cu partially formed an alloy with Pt and the remaining Cu existed as CuO. PtRu formed an alloy structure with a composition distribution of a Pt-rich core and Ru-rich shell. No alloying was observed in PtSn, which had a Pt-SnO2 structure. The alloy and oxide formation mechanisms are discussed considering the redox potentials, the standard enthalpy of oxide formation, and the solid solubilities of Pt and the counterpart metals.

  16. 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.

  17. Enhanced photocatalytic activity of Ag–ZnO hybrid plasmonic nanostructures prepared by a facile wet chemical method

    Directory of Open Access Journals (Sweden)

    Sini Kuriakose

    2014-05-01

    Full Text Available We report the synthesis of Ag–ZnO hybrid plasmonic nanostructures with enhanced photocatalytic activity by a facile wet-chemical method. The structural, optical, plasmonic and photocatalytic properties of the Ag–ZnO hybrid nanostructures were studied by X-ray diffraction (XRD, field emission scanning electron microscopy (FESEM, transmission electron microscopy (TEM, photoluminescence (PL and UV–visible absorption spectroscopy. The effects of citrate concentration and Ag nanoparticle loading on the photocatalytic activity of Ag–ZnO hybrid nanostructures towards sun-light driven degradation of methylene blue (MB have been investigated. Increase in citrate concentration has been found to result in the formation of nanodisk-like structures, due to citrate-assisted oriented attachment of ZnO nanoparticles. The decoration of ZnO nanostructures with Ag nanoparticles resulted in a significant enhancement of the photocatalytic degradation efficiency, which has been found to increase with the extent of Ag nanoparticle loading.

  18. 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.

  19. Enhanced photocatalytic activity of Co doped ZnO nanodisks and nanorods prepared by a facile wet chemical method.

    Science.gov (United States)

    Kuriakose, Sini; Satpati, Biswarup; Mohapatra, Satyabrata

    2014-07-07

    Cobalt doped ZnO nanodisks and nanorods were synthesized by a facile wet chemical method and well characterized by X-ray diffraction, field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM) with energy dispersive X-ray spectroscopy, photoluminescence spectroscopy, Raman spectroscopy and UV-visible absorption spectroscopy. The photocatalytic activities were evaluated for sunlight driven degradation of an aqueous methylene blue (MB) solution. The results showed that Co doped ZnO nanodisks and nanorods exhibit highly enhanced photocatalytic activity, as compared to pure ZnO nanodisks and nanorods. The enhanced photocatalytic activities of Co doped ZnO nanostructures were attributed to the combined effects of enhanced surface area of ZnO nanodisks and improved charge separation efficiency due to optimal Co doping which inhibit recombination of photogenerated charge carriers. The possible mechanism for the enhanced photocatalytic activity of Co doped ZnO nanostructures is tentatively proposed.

  20. 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.

  1. Optical and structural properties of ZnO hexagonal rods prepared by thermal chemical vapor deposition technique

    Directory of Open Access Journals (Sweden)

    A Reyhani

    2014-11-01

    Full Text Available In this research, ZnO nanostructure hexagonal pyramid rods with high optical and structural quality were synthesized by the simple thermal chemical vapor deposition of Zn powder without a metal catalyst. Surface morphologies were characterized by scanning electron microscopy (SEM. XRD analyses demonstrated that ZnO hexagonal pyramid rods had a wurtzite structure with the orientation of (002. Investigation of optical properties of samples by photoluminescence spectrum exhibited a sharp UV emission peak at 380nm. The quality and composition of the ZnO pyramid rods were characterized using the Fourier transform infrared spectrum (FTIR at room temperature. In addition, the growth mechanism of ZnO hexagonal rods is also briefly discussed.

  2. 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.

  3. Effect of Postannealing Treatment on Structural and Optical Properties of ZnO Nanorods Prepared Using Chemical Bath Deposition

    Science.gov (United States)

    Bidier, Shaker A.; Hashim, M. R.; Aldiabat, Ahmad M.

    2017-03-01

    ZnO nanorods have been synthesized on glass substrate by the chemical bath deposition technique. To investigate the effect of postannealing treatment on their crystalline and optical quality, the films were annealed at various temperatures of 300°C, 400°C, and 500°C in air ambient for 1 h. The morphological and chemical composition of the ZnO films were investigated using field-emission scanning electron microscopy (FESEM) with energy-dispersive spectroscopy (EDS). The structural properties were characterized by employing x-ray diffraction analysis and Raman spectroscopy. Finally, the optical properties were investigated by photoluminescence measurements. FESEM images revealed high-quality ZnO nanorods grown on the substrate surface. EDS results demonstrated a slight reduction in the quantity of oxygen after annealing. XRD and Raman results showed noticeable improvement in the crystalline quality of the ZnO films after annealing. The crystallite size increased significantly after annealing, from 40.5 nm for the nonannealed film to a maximum for 46.2 nm for the annealed samples. The photoluminescence results exhibited an increment in the optical quality [ultraviolet (UV) versus visible emission] after postannealing treatment. The enhancement in the crystalline and optical quality of the annealed films compared with the nonannealed sample is due to recrystallization of ZnO particles into a ZnO wurtzite lattice structure as well as relaxation of oxygen molecules adsorbed on the surface of the ZnO nanorods. This enhancement is conducive to improved efficiency for potential applications of ZnO.

  4. 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.

  5. 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.

  6. Chemical bonding structural analysis of nitrogen-doped ultrananocrystalline diamond/hydrogenated amorphous carbon composite films prepared by coaxial arc plasma deposition

    Science.gov (United States)

    Gima, Hiroki; Zkria, Abdelrahman; Katamune, Yūki; Ohtani, Ryota; Koizumi, Satoshi; Yoshitake, Tsuyoshi

    2017-01-01

    Nitrogen-doped ultra-nanocrystalline diamond/hydrogenated amorphous carbon composite films prepared in hydrogen and nitrogen mixed-gas atmospheres by coaxial arc plasma deposition with graphite targets were studied electrically and chemical-bonding-structurally. The electrical conductivity was increased by nitrogen doping, accompanied by the production of n-type conduction. From X-ray photoemission, near-edge X-ray absorption fine-structure, hydrogen forward-scattering, and Fourier transform infrared spectral results, it is expected that hydrogen atoms that terminate diamond grain boundaries will be partially replaced by nitrogen atoms and, consequently, π C–N and C=N bonds that easily generate free electrons will be formed at grain boundaries.

  7. 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.

  8. 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.

  9. Method of preparation of a CO.sub.2 removal sorbent with high chemical stability during multiple cycles

    Science.gov (United States)

    Siriwardane, Ranjani V.; Rosencwaig, Shira

    2015-07-14

    Method for the production of a clay-alkali-amine CO.sub.2 sorbent prepared by integrating a clay substrate, basic alkali salt, and amine liquid. The basic alkali salt is present relative to the clay substrate in a weight ratio of from about 1 part to about 50 parts per 100 parts of the clay substrate. The amine liquid is present relative to a clay-alkali combination in a weight ratio of from about 1 part to about 10 parts per 10 parts of the clay-alkali combination. The clay substrate and basic alkali salt may be combined in a solid-solid heterogeneous mixture and followed by introduction of the amine liquid. Alternatively, an alkaline solution may be blended with the amine solution prior to contacting the clay substrate. The clay-alkali-amine CO.sub.2 sorbent is particularly advantageous for low temperature CO.sub.2 removal cycles in a gas stream having a CO.sub.2 concentration less than around 2000 ppm and an oxygen concentration around 21%, such as air. Results are presented illustrating the performance of the clay-alkali-amine CO.sub.2 sorbent compared to a clay-amine sorbent lacking the alkali inclusion.

  10. Facile preparation of Ni{sub 2}P/ZnO core/shell composites by a chemical method and its photocatalytic performance

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Shuling, E-mail: shulingliu@aliyun.com [Key Laboratory of Auxiliary Chemistry & Technology for Chemical Industry, Ministry of Education, Shaanxi University of Science & Technology, Xi’an, Shaanxi 710021 (China); College of Chemistry & Chemical Engineering, Shaanxi University of Science & Technology, Xi’an, Shaanxi 710021 (China); Ma, Lanbing; Zhang, Hongzhe; Ma, Chenlu [Key Laboratory of Auxiliary Chemistry & Technology for Chemical Industry, Ministry of Education, Shaanxi University of Science & Technology, Xi’an, Shaanxi 710021 (China); College of Chemistry & Chemical Engineering, Shaanxi University of Science & Technology, Xi’an, Shaanxi 710021 (China)

    2016-05-15

    Graphical abstract: The typical SEM images and the schematic illustration of photocatalytic mechanism of as-prepared Ni{sub 2}P/ZnO core/shell composites. - Highlights: • Ni{sub 2}P/ZnO composites have been synthesized via a facile chemical precipitation method. • The effect of the amount of Zn{sup 2+} has been discussed. • Ni{sub 2}P/ZnO composite exhibits an enhanced photocatalytic degradation activity. • A mechanism about the enhanced photocatalytic activity is proposed. - Abstract: Ni{sub 2}P/ZnO core/shell composites were fabricated basing on combining hydrothermal route with a facile chemical precipitation method. The characterization results show that the composites are comprised of the hexagonal Ni{sub 2}P microspheres and hexagonal ZnO nanoparticles. In which, ZnO nanoparticles coat on the surfaces of Ni{sub 2}P microspheres and some of them even assemble to worm-like structure. During the coating process, Zn{sup 2+} was absorbed on the surface of Ni{sub 2}P microspheres by electrostatic interaction and then formed ZnO shell. But excessive Zn{sup 2+} can affect the crystalline and formation of core-shell structure of Ni{sub 2}P/ZnO composites, so it is necessary to control the amount of Zn{sup 2+}. Choosing Methylene Blue (MB) as a typical organic dye, the as-prepared Ni{sub 2}P/ZnO core/shell composites show the enhanced photocatalytic degradation activity, which may be due to its better adsorption ability and the effective separation of photogenerated electron–hole pairs.

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. Preparation of a-Si and a-Si-Alloy Films Using an Ion-Gun Chemical Vapor Deposition Method

    Science.gov (United States)

    Haku, Hisao; Sayama, Katsunobu; Matsuoka, Tsugufumi; Tsuda, Shinya; Nakano, Shoichi; Ohnishi, Michitoshi; Kuwano, Yukinori

    1991-07-01

    As a new amorphous-silicon (a-Si) fabrication technique, an ion-gun chemical vapor deposition (CVD) method, in which ions add energy to surface reactions, has been developed. The ion source employed in this gun is of the hot cathode type with a multicapillary anode which creates a collimated gas flow. A-Si:H and a-Ge:H films, fabricated at the substrate temperature of 130°C, show low dihydride bond density and high photosensitivity (4.0× 105 at Eopt˜1.95 eV and 5.1 at Eopt˜1.03 eV, respectively). In addition, a double ion-gun CVD method, for which the energy of two kinds of ion species can be independently controlled, has been developed for fabricating high-quality a-Si-alloy films. Highly photoconductive a-SiGe:H films with low optical gaps (<1.3 eV) were obtained using this fabrication method.

  16. Identification of higher order long-propagation-length surface plasmon polariton modes in chemically prepared gold nanowires.

    Science.gov (United States)

    Paul, Aniruddha; Solis, David; Bao, Kui; Chang, Wei-Shun; Nauert, Scott; Vidgerman, Leonid; Zubarev, Eugene R; Nordlander, Peter; Link, Stephan

    2012-09-25

    A comprehensive understanding of the type of modes and their propagation length for surface plasmon polaritons (SPPs) in gold nanowires is essential for potential applications of these materials as nanoscale optical waveguides. We have studied chemically synthesized single gold nanowires by a novel technique called bleach-imaged plasmon propagation (BlIPP), which relies on the plasmonic near-field induced photobleaching of a dye to report the SPP propagation in nanowires. We observed a much longer propagation length of 7.5 ± 2.0 μm at 785 nm compared to earlier reports, which found propagation lengths of ~2.5 μm. Finite difference time domain simulations revealed that the bleach-imaged SPP is a higher order m = 1 mode and that the lowest order m = 0 mode is strongly quenched due to the loss to the dye layer and cannot be resolved by BlIPP. A comparative assessment of BlIPP with direct fluorescence imaging furthermore showed that the significant difference in propagation lengths obtained by these two techniques can be attributed to the difference in their experimental conditions, especially to the difference in thickness of the dye layer coating on the nanowire. In addition to identifying a higher order SPP mode with long propagation length, our study infers that caution must be taken in selecting indirect measurement techniques for probing SPP propagation in nanoscale metallic waveguides.

  17. 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.

  18. Inverted organic solar cells with ZnO nanowalls prepared using wet chemical etching in a KOH solution.

    Science.gov (United States)

    Shin, Kyung-Sik; Park, Hye-Jeong; Kumar, Brijesh; Kim, Kwon-Ho; Kim, Sang-Hyeob; Kim, Sang-Woo

    2012-02-01

    We report on the photovoltaic (PV) performances of inverted organic solar cells (IOSCs) that were fabricated from PCBM:P3HT polymer with a ZnO thin film and ZnO nanowalls as electron transport and hole block layers. ZnO thin film on ITO/glass substrate was deposited using a simply aqueous solution route. ZnO nanowall structures were obtained via wet chemical etching of ZnO thin films in a KOH solution. The power conversion efficiency (PCE) of the IOSC with ZnO nanowalls was significantly improved by 44% from 1.254% to 1.811% compared to that of the IOSC with ZnO thin film. The short circuit current in IOSCs fabricated with the ZnO nanowalls was increased mainly due to the increase in the charge transport interface area, as a result of enhancement in the PCE. This work suggests a method for fabricating efficient PV devices with a larger charge transport area for future prospects.

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

    Science.gov (United States)

    Sun, W.; Xiong, X.; Huang, B. Y.; Li, G. D.; Zhang, H. B.; Xiao, P.; Chen, Z. K.; Zheng, X. L.

    2009-05-01

    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 ZrCl 4-C 3H 6-H 2-Ar source. Zirconium tetrachloride (ZrCl 4) 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/cm 3 by Archimedes' principle.

  20. The effect of cadmium vacancies on the optical properties of chemically prepared CdS quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Madan, Shikha; Kumar, Jitender; Singh, Inderpreet; Madhwal, Devinder; Bhatnagar, P K; Mathur, P C, E-mail: shikhamadan16@gmail.co [Material Science Laboratory, Department of Electronic Science, University of Delhi South Campus, Benito Juarez Road, New Delhi-110021 (India)

    2010-10-15

    CdS quantum dots (QDs) in a polyvinyl alcohol (PVA) matrix have been grown by a chemical method and are characterized by transmission electron microscopy (TEM), UV-vis absorption, photoluminescence (PL) and energy dispersive x-ray diffraction (EDX). TEM studies of CdS films show that a nearly spherical cluster of CdS QDs with an average radius of 10-15 nm is formed. From absorption measurements, it is observed that with increasing the PVA concentration from 5 to 8 wt.%, the absorption edge shifts from 3.1 to 3.6 eV, which is attributed to an increase in quantum confinement with decreasing the QD size. PL studies in an energy range of 1.8-3.3 eV show two distinct peaks. The higher-energy peak corresponds to band edge emission, whereas the lower-energy peak corresponds to defect emission. EDX results revealed that the atomic concentration of cadmium is much lower than that of sulfur, indicating that cadmium vacancies are predominant. It was concluded that cadmium vacancies are mainly responsible for defect emission in the PL spectrum.

  1. 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.

  2. Enhanced UVB emission and analysis of chemical states of Ca5(PO4)3OH:Gd3+,Pr3+ phosphor prepared by co-precipitation

    Science.gov (United States)

    Mokoena, P. P.; Nagpure, I. M.; Kumar, Vinay; Kroon, R. E.; Olivier, E. J.; Neethling, J. H.; Swart, H. C.; Ntwaeaborwa, O. M.

    2014-08-01

    Hydroxyapatite (Ca5(PO4)3OH) is a well-known bioceramic material used in medical applications because of its ability to form direct chemical bonds with living tissues. This mineral is currently used as a host for rare-earth ions (e.g. Gd3+, Pr3+, Tb3+, etc.) to prepare phosphors that can be used in light emitting devices of different types. In this study Ca5(PO4)3OH:Gd3+,Pr3+ phosphors were prepared by the co-precipitation method and were characterised by x-ray diffraction, x-ray photoelectron spectroscopy, scanning electron microscopy, high resolution transmission electron microscopy, energy dispersive x-ray spectroscopy and photoluminescence spectroscopy. The x-ray diffraction pattern was consistent with the hexagonal phase of Ca5(PO4)3OH referenced in JCPDS card number 73-0293. The x-ray photoelectron spectroscopy data indicated that Ca2+ occupied two different lattice sites, referred to as Ca1 and Ca2. The photoluminescence data exhibited a narrowband emission located at 313 nm, which is associated with the 6P7/2→8S7/2 transition of the Gd3+ ion. This emission is classified as ultraviolet B and it is suitable for use in phototherapy lamps to treat various skin diseases. The photoluminescence intensity of the 313 nm emission was enhanced considerably by Pr3+ co-doping.

  3. 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.

  4. Aqueous Chemical Solution Deposition of Novel, Thick and Dense Lattice-Matched Single Buffer Layers Suitable for YBCO Coated Conductors: Preparation and Characterization

    Directory of Open Access Journals (Sweden)

    Isabel van Driessche

    2012-09-01

    Full Text Available In this work we present the preparation and characterization of cerium doped lanthanum zirconate (LCZO films and non-stoichiometric lanthanum zirconate (LZO buffer layers on metallic Ni-5% W substrates using chemical solution deposition (CSD, starting from aqueous precursor solutions. La2Zr2O7 films doped with varying percentages of Ce at constant La concentration (La0.5CexZr1−xOy were prepared as well as non-stoichiometric La0.5+xZr0.5−xOy buffer layers with different percentages of La and Zr ratios. The variation in the composition of these thin films enables the creation of novel buffer layers with tailored lattice parameters. This leads to different lattice mismatches with the YBa2Cu3O7−x (YBCO superconducting layer on top and with the buffer layers or substrate underneath. This possibility of minimized lattice mismatch should allow the use of one single buffer layer instead of the current complicated buffer architectures such as Ni-(5% W/LZO/LZO/CeO2. Here, single, crack-free LCZO and non-stoichiometric LZO layers with thicknesses of up to 140 nm could be obtained in one single CSD step. The crystallinity and microstructure of these layers were studied by XRD, and SEM and the effective buffer layer action was studied using XPS depth profiling.

  5. 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.

  6. Wet chemical preparation and isotope exchange process of H/D-terminated Si(111) and Si(110) studied by adsorbate vibrational analysis

    Science.gov (United States)

    Kawamoto, Erina; Kang, Jungmin; Matsuda, Takuya; Yamada, Taro; Suto, Shozo

    2017-02-01

    A convenient procedure for preparing D-terminated Si(111)-(1×1) and Si(110)-(1×1) by wet chemical etching was developed and applied to the vibrational analysis of these surfaces by high-resolution electron-energy loss spectroscopy (HREELS). Fully H-terminated Si(111)/(110) was first prepared in regular 40% NH4F/H2O solution, followed by immersion in saturated KF/D2O solution. HREELS revealed partially D-terminated H:Si(111)/(110) with the amount of deuterium termination depending on the immersion time. A series of various immersion times revealed the H/D exchange reaction kinetics, which are associated with the Si substrate etching processes on Si(111) (step-flow etching) and Si(110) (zipper reaction). The H-Si and D-Si stretching vibration frequencies as functions of the surface D fraction did not appear to change on Si(111), but on Si(110) the H-Si signal red shifted at a high D fraction. This is due to the adsorbate-adsorbate interaction, which is more intense on Si(110) because of the short nearest-neighbor distance of the adsorbates.

  7. 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

    2012-04-03

    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.

  8. 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.

  9. 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.

  10. Comparison of Surface and Structural Properties of Carbonaceous Materials Prepared by Chemical Activation of Tomato Paste Waste: The Effects of Activator Type and Impregnation Ratio

    Directory of Open Access Journals (Sweden)

    Nurgul Ozbay

    2016-01-01

    Full Text Available Activated carbons were prepared by carbonization of tomato paste processing industry waste at 500°C followed by chemical activation with KOH, K2CO3, and HCl in N2 atmosphere at low temperature (500°C. The effects of different activating agents and impregnation ratios (25, 50, and 100 wt.% on the materials’ characteristics were examined. Precursor, carbonized tomato waste (CTW, and activated carbons were characterized by using ultimate and proximate analysis, thermogravimetric analysis (TG/DTG, Fourier transform-infrared (FT-IR spectroscopy, X-ray fluorescence (XRF spectroscopy, point of zero charge measurements (pHPZC, particle size analyzer, scanning electron microscopy (SEM, energy dispersive X-ray (EDX spectroscopy, nitrogen adsorption/desorption isotherms, and X-ray diffraction (XRD analysis. Activation process improved pore formation and changed activated carbons’ surface characteristics. Activated carbon with the highest surface area (283 m3/g was prepared by using 50 wt.% KOH as an activator. According to the experimental results, tomato paste waste could be used as an alternative precursor to produce low-cost activated carbon.

  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. 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

    2016-03-15

    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.

  13. In vitro Starch Hydrolysis Rate, Physico-chemical Properties and Sensory Evaluation of Butter Cake Prepared Using Resistant Starch Type III Substituted for Wheat Flour.

    Science.gov (United States)

    Pongjanta, J; Utaipattanaceep, A; Naivikul, O; Piyachomkwan, K

    2008-09-01

    Resistant starch type III (RS III) derived from enzymatically debranched high amylose rice starch was prepared and used to make butter cake at different levels (0, 5, 10, 15 and 20%) in place of wheat flour. Physico-chemical properties, sensory evaluation, and in vitro starch hydrolysis rate of the developed butter cake were investigated. This study showed that the content of resistant starch in butter cake increased significantly (Pstarch hydrolysis rate compared to the control cake (0% RS III). The rates of starch hydrolysis from 0 to 180 min digestion time for 0, 5, 10 15, and 20% RS III in place of wheat flour in butter cakes were 3.70 to 67.65%, 2.97 to 64.86%, 2.86 to 59.99%, 2.79 to 55.96 and 2.78 to 53.04% respectively. The physico-chemical properties of 5 to 10% RS III substituted with wheat flour in the butter cake were not significantly different from the control cake and were moderately accepted by panellists in the sensory evaluation test.

  14. 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.

  15. 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)

  16. 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.

  17. Preparation of double perovskite-type oxide LaSrFeCoO6for chemical looping steam methane reforming to produce syngas and hydrogen

    Institute of Scientific and Technical Information of China (English)

    赵坤; 沈阳; 何方; 黄振; 魏国强; 郑安庆; 李海滨; 赵增立

    2016-01-01

    Double-perovskite type oxide LaSrFeCoO6was used as oxygen carrier for chemical looping steam methane reforming (CL-SMR) due to its unique structure and reactivity. Solid-phase, amorphous alloy, sol-gel and micro-emulsion methods were used to prepare the LaSrFeCoO6samples, and the as-prepared samples were characterized by means of X-ray diffraction (XRD), hydrogen temperature-programmed reduction (H2-TPR), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) surface area. Results showed that the samples made by the four different methods exhibited pure crystalline perovskite structure. The ordered dou-ble perovskite LaSrFeCoO6was regarded as a regular arrangement of alternating FeO6and CoO6corner-shared octahedra, with La and Sr cations occupying thevoids in between the octahedral. Because the La3+and Sr2+ions in A-site didnot take part in reaction, the TPR patterns showedthe reductive properties of the B-site metals. The reduction peaks at low temperature revealed the reduction of adsorbed oxygenon surface and combined with the reduction of Co3+to Co2+and to Co0, while the reduction of Fe3+to Fe2+and the partial reduction of Fe2+to Fe0occurred at higher temperatures. From the point of view of the oxygen-donation ability, resistance to carbon formation, as well as hydrogen generation capacity, the sample made by micro-emulsion method exhibited the best reactiv-ity. Its redox reactivitywas very stable in ten successive cycles without deactivation. Compared to the single perovskite-type oxides LaFeO3and LaCoO3, the double perovskite LaSrFeCoO6exhibitedbetter syngas and hydrogen generation capacity.

  18. 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.

  19. Preparation of nanocrystalline of NiO by ultrasonic chemical precipitation method%超声化学沉淀法制备纳米NiO

    Institute of Scientific and Technical Information of China (English)

    张乐观; 贺茂云; 成功; 肖波

    2011-01-01

    Nano-NiO powder was prepared with Ni(NO3)2·6H2O and (NH4)2C2O4 · H2O as raw materials by ultrasonic chemical precipitation method. Composition and morphology of precursor and product were characterized with XRD,FT-IR and TEM. Experiment results showed that the precursor of nickel oxalate dehydrate was obtained via ultrasonic chemical precipitation method. Compared with bulk-NiO, Ni-O stretching vibration absorption and acromion peaks of the nano-NiO products in FT-IR pattern give rise to red-shift. The NiO nanoparticles were spherical in shape, smooth edges, weak agglomeration and homogeneous particle size (average about 70nm).%以Ni(NO3)2·6H2O和(NH4)2C2O4·H2O为原料,采用超声沉淀法制备了纳米NiO,并利用XRD、FT-IR和TEM等分析方法对前驱体及产品组成和形貌进行了表征.结果表明,超声沉淀法制备的纳米NiO前驱体是二水合草酸镍.和实验制备的大颗粒Nio相比,纳米氧化镍Ni-O伸缩振动吸收峰及肩峰均发生了红移.纳米NiO为球型形貌,边缘清晰光滑,粒子尺寸较为均匀,有轻微的团聚,其平均粒径约为70nm.

  20. 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.

  1. Basis for calculating technological parameters of preparation of minced salted fish products of intermediate moisture with specified physical and chemical characteristics

    Directory of Open Access Journals (Sweden)

    Stepanenko E. I.

    2016-09-01

    Full Text Available The dependence of water activity on basic physical and chemical characteristics of salted fish products with intermediate moisture has been defined. During the research the product quality has been assessed by the organoleptic method; determination of the water mass fraction has been carried out by the drying method; the salt mass fraction – by the argentometric method; water activity has been measured by a cooled mirror dew-point sensor. Based on experimental data the dependence of Aw on concentration of sodium chloride in the salt semi-finished products of pollock (Theragra chalcogramma, Atlantic herring (Clupea harengus, Baltic cod (Gadus morhua callarias, blue whiting (Micromesistius, pink salmon (Oncorhynchus gorbuscha, horse mackerel (Trachurus trachurus has been established. The empirical formula showing the correlation of the parameter (Aw with mass fraction of sodium chloride and water has been derived; on its basis it is possible to calculate the parameters of semi-finished product in order to obtain a final minced salt product of intermediate moisture with desired microbial stability upon storage. The relations between the salt mass fraction and water mass fraction excluding bacterial spoilage and mold growth has been determined, they make up S ≥ 0,135 ∙ W and S ≥ 0,34 ∙ W respectively, where S – the mass fraction of salt, %, W – the mass fraction of water, %. An example of calculating the required dosage of sodium chloride in the semi-finished minced salmon has been described to produce the finished product with the exactly given values of humidity and water activity. During the process of minced salted fish products' dehydration the basic physical and chemical parameters – the mass fraction of salt and water affecting the water activity (Aw – have been changing. Determination of these parameters' relationship provides the ability to predict the qualitative changes of salted fish products of intermediate moisture

  2. 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.

  3. Chemical preparation of crystalline, nonmolecular solids, including solution-liquid-solid (SLS) growth of semiconductor fibers and varied routes to nanocrystalline molybdenum disilicide

    Science.gov (United States)

    Trentler, Timothy John

    New methods for the preparation of crystalline, nonmolecular solids under milder conditions and/or with control of crystallite size or morphology were developed in two separate projects. In one project, polycrystalline 13-15 semiconductor fibers (dimensions 10-100 nm x 50-1000 nm) were grown by solution-based chemical methods. Crystal precursor species of the general formula (Rsb{x}InEHsb{x}rbracksb{n}, where E is a pnictide and R is an alkyl group, were prepared by the phosphinolysis or arsinolysis of alkylindanes in aromatic solvents. Thermal decomposition of these precursors in solution, which was catalyzed by various protic reagents (MeOH, PhSH, Etsb2NH, or PhCOsb2H), resulted in crystalline InE when In metal was present in the form of submicron droplets dispersed in the solvent. Crystallization was determined to occur (at the lowest temperatures reported for 13-15 semiconductors, liquid-solid (SLS) mechanism reminiscent of vapor-liquid-solid (VLS) growth of single-crystal whiskers. Some analogous reactions were investigated in which t-Busb3Ga was mixed with the alkylindane in order to prepare ternary alloys (Insb{x}Gasb{1-x}As). Product crystallinity and composition was dependent on, though not exclusively determined by, the indane/gallane ratio. Crystals with composition within the miscibility gap for this alloy system were grown. The focus of the other project was the preparation of nanocrystalline (crystallite dimensions NaK alloy in an ultrasonically agitated hydrocarbon solvent followed by thermal processing (900sp°C) under vacuum to eliminate byproduct salts. MoSisb2 crystallites averaging 20-50 nm were obtained. Solvent degradation during this process resulted in the incorporation of substantial carbonaceous impurity (believed to be SiC) in these products. To eliminate the carbon, similar solventless reductions (without ultrasound) were conducted in molten magnesium, but average particle sizes have not been refined into the nanometer regime (currently

  4. Tribological properties and thermal stability of hydrogenated, silicon/nitrogen-coincorporated diamond-like carbon films prepared by plasma-enhanced chemical vapor deposition

    Science.gov (United States)

    Nakazawa, Hideki; Okuno, Saori; Magara, Kohei; Nakamura, Kazuki; Miura, Soushi; Enta, Yoshiharu

    2016-12-01

    We have deposited hydrogenated, silicon/nitrogen-incorporated diamond-like carbon (Si-N-DLC) films by plasma-enhanced chemical vapor deposition using hexamethyldisilazane [((CH3)3Si)2NH; HMDS] as the Si and N source, and compared the tribological performance and thermal stability of the Si-N-DLC films with those of hydrogenated, Si-incorporated DLC (Si-DLC) films prepared using dimethylsilane [SiH2(CH3)2] as the Si source. The deposited films were annealed at 723-873 K in air atmosphere. The friction coefficients of hydrogenated DLC films after annealing significantly increased at the initial stages of friction tests. On the other hand, the friction coefficients of the Si-N-DLC films deposited at an HMDS flow ratio [HMDS/(HMDS+CH4)] of 2.27% remained low after the annealing even at 873 K. We found that the wear rate of the Si-N-DLC film deposited at 2.27% and -1000 V remained almost unchanged after the annealing at 873 K, whereas that of the Si-DLC film with a similar Si fraction deposited at -1000 V significantly increased after the annealing at 773 K.

  5. 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.

  6. Hot-wire chemical vapor deposition prepared aluminum doped p-type microcrystalline silicon carbide window layers for thin film silicon solar cells

    Science.gov (United States)

    Chen, Tao; Köhler, Florian; Heidt, Anna; Carius, Reinhard; Finger, Friedhelm

    2014-01-01

    Al-doped p-type microcrystalline silicon carbide (µc-SiC:H) thin films were deposited by hot-wire chemical vapor deposition at substrate temperatures below 400 °C. Monomethylsilane (MMS) highly diluted in hydrogen was used as the SiC source in favor of SiC deposition in a stoichiometric form. Aluminum (Al) introduced from trimethylaluminum (TMAl) was used as the p-type dopant. The material property of Al-doped p-type µc-SiC:H thin films deposited with different deposition pressure and filament temperature was investigated in this work. Such µc-SiC:H material is of mainly cubic (3C) SiC polytype. For certain conditions, like high deposition pressure and high filament temperature, additional hexagonal phase and/or stacking faults can be observed. P-type µc-SiC:H thin films with optical band gap E04 ranging from 2.0 to 2.8 eV and dark conductivity ranging from 10-5 to 0.1 S/cm can be prepared. Such transparent and conductive p-type µc-SiC:H thin films were applied in thin film silicon solar cells as the window layer, resulting in an improved quantum efficiency at wavelengths below 480 nm.

  7. 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.

  8. Preparation of silver nanowires coated with TiO2 using chemical binder and their applications as photoanodes in dye sensitized solar cell

    Science.gov (United States)

    Jang, Inseok; Kang, Taeho; Cho, Woohyung; Kang, Yong Soo; Oh, Seong-Geun; Im, Seung Soon

    2015-11-01

    In this study, the core-shell structured Ag@TiO2 wire was prepared for application to dye-sensitized solar cell (DSSC). The Ag nanowire, having an excellent electrical conductivity, was synthesized by using the facile microwave-assisted polyol reduction process. The diameter and length of Ag wires were 40-50 nm and 20-30 μm, respectively, and the face-centered cubic silver crystal structure was obtained. In the presence of 2-mercaptoethanol as a chemical binder, the entire surface of Ag wire was coated with the TiO2 shell, which has thickness of 20 nm, through solvothermal method. The crystalline structure of TiO2 shell was the anatase phase possessing an advantage to achieve the high efficiency in DSSC. The core-shell structured Ag@TiO2 wire exhibited the high thermal stability. The high conversion efficiency (5.56%) in fabricated device with Ag@TiO2 electrode, which is about 10% higher than reference cell, was achieved by enhancement of short-current density (Jsc) value. The core-shell structured Ag@TiO2 wire could effectively reduce the charge recombination through the contribution to electron shortcut for improvement in the electron transfer rate and lifetime.

  9. Growth, structural and optical properties of ternary InGaN nanorods prepared by selective-area metalorganic chemical vapor deposition.

    Science.gov (United States)

    Song, Jie; Leung, Benjamin; Zhang, Yu; Han, Jung

    2014-06-06

    Ternary InGaN nanorods were prepared on dielectric-masked nano-holes with selective area metalorganic chemical vapor deposition. To overcome the tendency for random nucleation of GaN at low temperatures, a pulsed growth procedure was introduced to enhance the diffusion length of Ga adatoms on SiO2, resulting in good selectivity at typical temperature ranges for InGaN. Photoluminescence from the InGaN nanorods can be tuned from near ultraviolet (400 nm) to blue-green (~500 nm). Microstructural properties were characterized by transmission electron microscopy; threading dislocations from the underlying GaN template were terminated at the nanorod/template interface, resulting in dislocation-free nanorods. The height of dislocation-free InGaN nanorods is about 150 nm, which is much larger than the critical thickness for the onset of misfit dislocations in planar InGaN growth with typical thickness of less than 10 nm for an indium composition between 10 and 20%. The composition profile of In along the growth direction was examined by energy dispersive x-ray spectroscopic mapping and line scan. Oscillations of In composition along the growth direction were observed and are likely due to the kinetic competition between In and Ga adatoms. These InGaN nanorods are expected to be useful as templates for growing higher In composition nano-light-emitting diodes.

  10. SiO{sub 2}/TiO{sub 2} thin films with variable refractive index prepared by ion beam induced and plasma enhanced chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Gracia, F. [Instituto de Ciencia de Materiales de Sevilla (CSIC-Univ. Sevilla) and Dpt. Q. Inorganica, Avda. Americo Vespucio s/n, 41092 Sevilla (Spain); Yubero, F. [Instituto de Ciencia de Materiales de Sevilla (CSIC-Univ. Sevilla) and Dpt. Q. Inorganica, Avda. Americo Vespucio s/n, 41092 Sevilla (Spain); Holgado, J.P. [Instituto de Ciencia de Materiales de Sevilla (CSIC-Univ. Sevilla) and Dpt. Q. Inorganica, Avda. Americo Vespucio s/n, 41092 Sevilla (Spain); Espinos, J.P. [Instituto de Ciencia de Materiales de Sevilla (CSIC-Univ. Sevilla) and Dpt. Q. Inorganica, Avda. Americo Vespucio s/n, 41092 Sevilla (Spain); Gonzalez-Elipe, A.R. [Instituto de Ciencia de Materiales de Sevilla (CSIC-Univ. Sevilla) and Dpt. Q. Inorganica, Avda. Americo Vespucio s/n, 41092 Sevilla (Spain)]. E-mail: arge@icmse.csic.es; Girardeau, T. [Laboratoire de Metallurgie Physique de Poitiers, UMR 6630 CNRS, Bat SP2MI BP 30179, 86962-Futuroscope-Chasseneuil Cedex (France)

    2006-04-03

    SiO{sub 2}/TiO{sub 2} optical thin films with variable compositions have been prepared by ion beam induced and plasma enhanced chemical vapour deposition (IBICVD and PECVD). While the films obtained by IBICVD were very compact, the PECVD ones with a high content of Ti presented a columnar microstructure. The formation of Si-O-Ti bonds and a change in the environment around titanium from four- to six-coordinated has been proved by vibrational and X-ray absorption spectroscopies. The refractive index increased with the titanium content from 1.45 to 2.46 or 2.09 for, respectively, the IBICVD and PECVD films. Meanwhile, the band gap decreased, first sharply and then more smoothly up to the value of pure TiO{sub 2}. It is concluded that the optical properties of SiO{sub 2}/TiO{sub 2} thin films can be properly tailored by using these two procedures.

  11. Preparation of Carbon Fiber Composites by Chemical Coating%碳纤维复合材料化学镀工艺研究

    Institute of Scientific and Technical Information of China (English)

    尹艳华; 赵京磊; 王春芳

    2013-01-01

    为确定最佳化学镀制备碳纤维复合材料工艺条件,用X射线衍射仪(XRD)、扫描电镜(SEM)等表征涂镀产物的组成及形貌.实验结果表明:温度、pH值、装载量、纤维长度和搅拌方式对施镀效果有影响,镀铜最佳工艺条件为温度60℃,pH=12,装载量60 mg/250 mL,碳纤维长度为1 mm.镀铜镍碳纤维(CNCF)的镀层元素为铜和镍,镀层均匀,铜、镍为多晶,结晶质量、表面一致性良好,电镜确定铜层厚度约为1 μm,与理论计算0.96μm基本吻合.%To optimize the processing conditions of chemical metal coating for preparing carbon fiber composites, X-ray diffractions (XRD) and scanning electron microscope (SEM) were used to determine the composition and observe the morphology of the coating. Experiment results show that the factors that affect the coating quality are PH value of the solution, temperature, coated load, carbon fiber length and the stirring way. Under experimental environment, the optimized copper coating conditions are T=60℃ , pH = 12, loading 60 mg/250 mL and the length of the carbon fiber is 1 mm. SEM of chemical copper coating of nickel-carbon fiber (CNCF) shows that the coating is uniform with good quality and the copper and nickel present poly-crystal status. The observed surface copper thickness of CNCF is about 1 μm, which nearly coincides with the calculation thickness of 0. 96 μm.

  12. 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

  13. 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

    2013-10-07

    Nanoflaky MnO(x) on carbon nanotubes (nf-MnO(x)@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 MnO(x) and the obtained catalyst exhibited a large surface area as well. Compared with the MnO(x)/CNT and MnO(x)/TiO₂ catalysts prepared by an impregnation method, the nf-MnO(x)@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 Mn(4+) and more chemisorbed oxygen species existed on the surface of CNTs for nf-MnO(x)@CNTs. The H₂-TPR and NH₃-TPD results demonstrated that the nf-MnO(x)@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-MnO(x)@CNT catalyst has an excellent performance in the low-temperature SCR of NO to N₂ with NH₃. In addition, the nf-MnO(x)@CNT catalyst also presented favourable stability and H₂O resistance.

  14. Structural properties and visible emission of Eu3+-activated SiO2-ZnO-TiO2 powders prepared by a soft chemical process

    Science.gov (United States)

    Almeida, M. P. S.; Nunes, L. M.; Gonçalves, R. R.; Ribeiro, S. J. L.; Maia, L. J. Q.

    2016-12-01

    In this work, the structural and optical properties of the 60SiO2-20ZnO-20TiO2 system (in mol%) doped with 1 mol% of Eu3+ were evaluated. Stable and transparent sols, homogeneous gels, and powders were prepared by a soft chemical process followed by annealing from 700 to 1100 °C. Visible emission was observed in the photoluminescence (PL) spectra from 570 to 700 nm owing to the Eu3+ ions, with the most intense emission peaks at 614 and 590 nm related to the 5D0 → 7F2 and 5D0 → 7F1 transitions, corresponding to red (R) and orange (O) colors, respectively. The R/O intensity ratios between 3.16 and 3.73 were observed and correlated to the structural properties of the host. X-ray diffraction patterns indicated that the reduction of PL at 614 nm and changes in the R/O values were due to the crystallization process. In addition, the FTIR spectra showed a gradual decrease of the hydroxyl absorption bands around 3436 and 1640 cm-1 and an increase of the bands related to Ti-O-Ti and Si-O-Si linkages, indicating polymerization and densification process of the host was achieved above 700 °C. Moreover, increasing the annealing temperature resulted in the formation of ZnTiO3 and Zn2TiO4 crystalline phases, as well as rutile TiO2. Finally, intensity parameters (Ωλ), and quantum efficiency were calculated by applying Judd-Ofelt theory to Eu3+ ions, which showed that the Eu3+-doped samples can be used in displays and LEDs.

  15. Research and Advance of Chemic Preparation of Starch Super Water Absorbent Resin%淀粉系高吸水性树脂化学制备方法的研究进展

    Institute of Scientific and Technical Information of China (English)

    张大勤

    2011-01-01

    The chemic preparation of starch super water absorbent resin are reviewed in this paper.The principle of is analyzed for two normal methods of preparation.Prospect of starch super water absorbent resin is made in this paper.%本文综述了淀粉系高吸水树脂的化学制备方法。主要分析了常见两种方法的制备原理。对淀粉系高吸水树脂的发展前景作了展望。

  16. 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.

  17. 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...

  18. 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.

  19. 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

  20. Preparation of activate carbon with high specific surface area from beer lees by chemical activation with KOH; Suisankakariumu wo mochiita yakuhin fukatsuho ni yoru birukasu karano kohihyoumenseki kasseitan no seizo

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, J.; Kubo, A.; Furukawa, A.; Muroyama, K. [Kansai University, Osaka (Japan). Dept. of Chemical Engineering

    2000-03-10

    Activated carbons with high specific surface area were prepared from beer lees by chemical activation with KOH. We examined the influence of the preparation conditions, such as temperature and impregnation ratio, on the pore structure of the prepared activated carbon. The specific surface area increased with an increase in carbonization temperature up to 800 degree C and decreased at 900 degree C because of excess activation. It reached a maximum value at the impregnation ratio of 2.0. The activated carbon, which was prepared at the carbonization temperature of 800 degree C and at the impregnation ratio of 2.0, had very high specific surface area of 2,440 m{sup 2}/g. It was found that KOH worked effectively as the activating reagent in two temperature ranges, below 500 degree C and above 600 degree C. The amount of benzene and acetone adsorbed on the prepared activated carbon were much larger than that on the commercial activated carbons. (author)

  1. 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

  2. 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

  3. Existing chemicals: international activities.

    Science.gov (United States)

    Purchase, J F

    1989-01-01

    The standards of care used in the protection of the health and safety of people exposed to chemicals has increased dramatically in the last decade. Standards imposed by regulation and those adopted by industry have required a greater level of knowledge about the hazards of chemicals. In the E.E.C., the 6th amendment of the dangerous substances directive imposed the requirement that al new chemicals should be tested according to prescribed programme before introduction on to the market. The development of a European inventory of existing chemicals was an integral part of the 6th amendment. It has now become clear that increased standards of care referred to above must be applied to the chemicals on the inventory list. There is, however, a considerable amount of activity already under way in various international agencies. The OECD Chemicals Programme has been involved in considering the problem of existing chemicals for some time, and is producing a priority list and action programme. The International Programme on Chemical Safety produces international chemical safety cards, health and safety guides and environmental health criteria documents. The international register of potentially toxic compounds (part of UNEP) has prepared chemical data profiles on 990 compounds. The International Agency for Research on Cancer prepared monographs on the carcinogenic risk of chemicals to man. So far 42 volumes have been prepared covering about 900 substances. IARC and IPCS also prepare periodic reports on ongoing research on carcinogenicity or toxicity (respectively) of chemicals. The chemical industry through ECETOC (the European Chemical Industry Ecology and Toxicology Centre) has mounted a major initiative on existing chemicals. Comprehensive reviews of the toxicity of selected chemicals are published (Joint Assessment of Commodity Chemicals). In its technical report no. 30 ECETOC lists reviews and evaluations by major national and international organisations, which provides

  4. 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.

  5. 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.

  6. Structural and superconducting properties of La2−xNdxCuO4+y (0≤x≤0.5) prepared by room temperature chemical oxidation

    DEFF Research Database (Denmark)

    Rial, C.; Morán, E.; Alario-Franco, M.A.;

    1997-01-01

    The systematic characterization of the structural and superconducting properties of room temperature chemically oxidized T/O La2-xNdxCuO4+y (0 less than or equal to x less than or equal to 0.5) has been performed by neutron powder diffraction and magnetic susceptibility measurements. Similarities...

  7. 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

  8. Physical and chemical characteristics of ultrasonically-prepared water-in-diesel fuel: effects of ultrasonic horn position and water content.

    Science.gov (United States)

    Kojima, Yoshihiro; Imazu, Hiroki; Nishida, Keiichi

    2014-03-01

    An ultrasonic technique was applied to preparation of two-phase water-in-oil (W/O) emulsified fuel of water/diesel oil/surfactant. In this study, an ultrasonic apparatus with a 28 kHz rod horn was used. The influence of the horn tip position during ultrasonic treatment, sonication time and water content (5 or 10 vol%) on the emulsion stability, viscosity, water droplet size and water surface area of emulsion fuels prepared by ultrasonication was investigated. The emulsion stability of ultrasonically-prepared fuel significantly depended on the horn tip position during ultrasonic irradiation. It was found that the change in the stability with the horn tip position was partly related to that in the ultrasonic power estimated by calorimetry. Emulsion stability, viscosity and sum of water droplets surface area increased and water droplet size decreased with an increase in sonication time, and they approached each limiting value in the longer time. The maximum values of the viscosity and water surface area increased with water content, while the limiting values of the emulsion stability and water droplet size were almost independent of water content. During ultrasonication of water/diesel oil mixture, the hydrogen and methane were identified and the cracking of hydrocarbon components in the diesel oil occurred. The combustion characteristics of ultrasonically-prepared emulsion fuel were studied and compared with those of diesel oil. The soot and NOx emissions during combustion of the emulsified fuel with higher water contents were significantly reduced compared with those during combustion of diesel oil.

  9. 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.

  10. 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.

  11. 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.

  12. Preference of multi-walled carbon nanotube (MWCNT) to single-walled carbon nanotube (SWCNT) and activated carbon for preparing silica nanohybrid pickering emulsion for chemical enhanced oil recovery (C-EOR)

    Science.gov (United States)

    AfzaliTabar, M.; Alaei, M.; Ranjineh Khojasteh, R.; Motiee, F.; Rashidi, A. M.

    2017-01-01

    The aim of this research was to determine the best nano hybrid that can be used as a Pickering emulsion Chemical Enhanced Oil Recovery (C-EOR). Therefore, we have prepared different carbon structures nano hybrids with SiO2 nano particles with different weight percent using sol-gel method. The as-prepared nano materials were characterized with X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FE-SEM) and Thermal Gravimetric Analysis (TGA). Pickering emulsions of these nanohybrids were prepared at pH=7 in ambient temperature and with distilled water. Stability of the mentioned Pickering emulsions was controlled for one month. Emulsion phase morphology was investigated using optical microscopic imaging. Evaluation results demonstrated that the best sample is the 70% MWCNT/SiO2 nanohybrid. Stability of the selected nanohybrid (70% MWCNT/SiO2 nanohybrid) was investigated by alteration of salinity, pH and temperature. Results showed that the mentioned Pickering emulsion has very good stability at 0.1%, 1% salinity, moderate and high temperature (25 °C and 90 °C) and neutral and alkaline pH (7, 10) that is suitable for the oil reservoirs conditions. The effect of the related nano fluid on the wettability of carbonate rock was investigated by measuring the contact angle and interfacial tension. Results show that the nanofluid could significantly change the wettability of the carbonate rock from oil wet to water wet and can decrease the interfacial tension. Therefore, the 70% MWCNT/SiO2 nanohybrid Pickering emulsion can be used for Chemical Enhanced Oil Recovery (C-EOR).

  13. Effect of deposition variables on properties of CBD ZnS thin films prepared in chemical bath of ZnSO4/SC(NH2)2/Na3C3H5O7/NH4OH

    Science.gov (United States)

    Liu, Wei-Long; Yang, Chang-Siao; Hsieh, Shu-Huei; Chen, Wen-Jauh; Fern, Chi-Lon

    2013-01-01

    The CBD ZnS thin films were prepared on substrates of soda lime glass in chemical bath. The effect of deposition variables including zinc sulfate, thiourea, tri-sodium citrate, ammoina water, bath temperature, and deposition time on the properties of CBD ZnS thin films were comprehensively studied. The CBD ZnS thin films were characterized by a field emission scanning electron microscope (FESEM) for the surface and cross section morphologies and thicknesses, an energy dispersive spectrometer equipped in FESEM for the atomic% of Zn and S, an ultraviolet-visible spectrometer (300-800 nm) for the transmittance and energy gap, and an atomic force microscope for the surface roughness. The results showed that the CBD ZnS thin films have a transmittance for ultraviolet-visible rays (300-800 nm) from 70.8 to 87.8%. The CBD ZnS thin films prepared in bath 5 have an energy gap from 3.881 to 3.980 eV. The CBD ZnS thin films prepared in bath 6 have a growth rate from 1.8 to 3.2 nm/min and activation energy of 59.8 kJ/mol for their growth.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. STRUCTURAL AND SUPERCONDUCTING PROPERTIES OF LA2-XSRXCUO4+Y (0-LESS-THAN-X-LESS-THAN-0.15) PREPARED BY ROOM-TEMPERATURE CHEMICAL OXIDATION

    DEFF Research Database (Denmark)

    Rial, C.; Morán, E.; Alario-Franco, M.A.;

    1995-01-01

    The presence of interstitial oxygen in room temperature chemically oxidized La2-xSrxCuO4+y, (0.15superconducting properties of these cuprates. The existence of a structural limit for the insertion of oxygen under the current oxidation...... conditions, related to the relieving of the internal strain of these materials, is proposed. Besides, oxidized materials show an almost constant T-c close to that corresponding to the optimum hole doping concentration. The coincidence of both features is remarked upon and discussed....

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. Effects of Post Annealing Treatments on the Interfacial Chemical Properties and Band Alignment of AlN/Si Structure Prepared by Atomic Layer Deposition.

    Science.gov (United States)

    Sun, Long; Lu, Hong-Liang; Chen, Hong-Yan; Wang, Tao; Ji, Xin-Ming; Liu, Wen-Jun; Zhao, Dongxu; Devi, Anjana; Ding, Shi-Jin; Zhang, David Wei

    2017-12-01

    The influences of annealing temperature in N2 atmosphere on interfacial chemical properties and band alignment of AlN/Si structure deposited by atomic layer deposition have been investigated based on x-ray photoelectron spectroscopy and spectroscopic ellipsometry. It is found that more oxygen incorporated into AlN film with the increasing annealing temperature, resulting from a little residual H2O in N2 atmosphere reacting with AlN film during the annealing treatment. Accordingly, the Si-N bonding at the interface gradually transforms to Si-O bonding with the increasing temperature due to the diffusion of oxygen from AlN film to the Si substrate. Specially, the Si-O-Al bonding state can be detected in the 900 °C-annealed sample. Furthermore, it is determined that the band gap and valence band offset increase with increasing annealing temperature.

  4. 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.

  5. Annealing effects on capacitance-voltage characteristics of a-Si/SiN(x) multilayer prepared using hot-wire chemical vapour deposition.

    Science.gov (United States)

    Panchal, A K; Rai, D K; Solanki, C S

    2011-04-01

    Post-deposition annealing of a-Si/SiN(x) multilayer films at different temperature shows varying shift in high frequency (1 MHz) capacitance-voltage (HFCV) characteristics. Various a-Si/SiN(x) multilayer films were deposited using hot wire chemical vapor deposition (HWCVD) and annealed in the temperature range of 800 to 900 degrees C to precipitate Si quantum dots (Si-QD) in a-Si layers. HFCV measurements of the as-deposited and annealed films in metal-insulator-semiconductor (MIS) structures show hysterisis in C-V curves. The hysteresis in the as-deposited films and annealed films is attributed to charge trapping in Si-dangling bonds in a-Si layer and in Si-QD respectively. The charge trapping density in Si-QD increases with temperature while the interface defects density (D(it)) remains constant.

  6. 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.

  7. Effects of Post Annealing Treatments on the Interfacial Chemical Properties and Band Alignment of AlN/Si Structure Prepared by Atomic Layer Deposition

    Science.gov (United States)

    Sun, Long; Lu, Hong-Liang; Chen, Hong-Yan; Wang, Tao; Ji, Xin-Ming; Liu, Wen-Jun; Zhao, Dongxu; Devi, Anjana; Ding, Shi-Jin; Zhang, David Wei

    2017-02-01

    The influences of annealing temperature in N2 atmosphere on interfacial chemical properties and band alignment of AlN/Si structure deposited by atomic layer deposition have been investigated based on x-ray photoelectron spectroscopy and spectroscopic ellipsometry. It is found that more oxygen incorporated into AlN film with the increasing annealing temperature, resulting from a little residual H2O in N2 atmosphere reacting with AlN film during the annealing treatment. Accordingly, the Si-N bonding at the interface gradually transforms to Si-O bonding with the increasing temperature due to the diffusion of oxygen from AlN film to the Si substrate. Specially, the Si-O-Al bonding state can be detected in the 900 °C-annealed sample. Furthermore, it is determined that the band gap and valence band offset increase with increasing annealing temperature.

  8. Structure, Morphology and Chemical Synthesis of Mg1-xZnxFe2O4 Nano-Ferrites Prepared by Citrate-Gel Auto Combustion Method

    Directory of Open Access Journals (Sweden)

    D.Ravikumar

    2014-04-01

    Full Text Available Mg-Zn Nano ferrites having chemical formula Mg1-xZnxFe2O4(where x=0.0, 0.2, 0.4, 0.6, 0.8, 1.0 were synthesized by the citrate-gel auto combustion method. Synthesized powders were sintered at 500oC for four hours in air and characterized by XRD, SEM and EDS.XRD analysis shows that cubic spinal structure of the ferrites and the crystalline sizes (D were found in the range 25-35 nm. The values of the lattice parameter (a increases and X-ray density (dx increases with doping of Zn content. Scanning Electron Microscopy (SEM studies revealed Nano nature of the samples. An elemental composition of the samples was studied by using Energy Dispersive Spectroscopy (EDS. The observed results can be explained on the basis of composition and crystallite size.

  9. 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.

  10. Dielectric and phase transition of BaTi0.6Zr0.4O3 ceramics prepared by a soft chemical route

    Science.gov (United States)

    Rout, S. K.; Badapanda, T.; Sinha, E.; Panigrahi, S.; Barhai, P. K.; Sinha, T. P.

    2008-04-01

    BaTi0.6Zr0.4O3 (BTZ) ceramic was synthesized by a soft chemical route. X-ray diffraction at room temperature shows that the sample has cubic perovskite structure with space group Pm-3m. Temperature dependent dielectric study of the sample has been investigated in the frequency range from 50 Hz to 1 MHz. The density of the sample was determined using Archimedes’ principle and found to be ˜ 97% of the X-ray density. The average grain size in the pallet was found to be ˜ 1 μm. The dielectric constant peaks at temperature Tm which is dependent on the frequency. The dielectric relaxation rate follows the Vogel Fulcher relation with activation energy = 0.0185 eV, and freezing temperature = 186 K. All these measurements confirm that BTZ is a relaxor ferroelectric.

  11. Effects of extra oxygen on the structure and superconductivity of La2-xCaxCuO4+y prepared by chemical oxidation

    DEFF Research Database (Denmark)

    Rial, C.; Moran, E.; Alario Franco, M.A.

    1998-01-01

    The insertion of an excess of oxygen within the structure of La2-xCaxCuO4 (x less than or equal to 0.12) by means of room temperature chemical oxidation modifies the physical properties and the crystal structure of these cuprates. The superconducting features of the starting La2-xCaxCuO4 samples......(c)s. This decrease of T-c is connected with the ability of these compounds to incorporate extra oxygen, which decreases as the Ca-doping increases and is controlled by a structural limit. The behavior of the La2-xCaxCuO4 materials under the oxidation process and the changes induced by the interstitial oxygen...... and the differences concerning the insertion of oxygen and the modifications induced in La2-xMxCuO4+y (M = Ca, Sr, Ba) are presented and discussed. (C) 1998 Elsevier Science B.V....

  12. Characterization of Pb(Zr, Ti)O sub 3 thin films prepared by metal-organic chemical-vapor deposition using a solid delivery system

    CERN Document Server

    Shin, J C; Hwang, C S; Kim, H J; Lee, J M

    1999-01-01

    Pb(Zr, Ti)O sub 3 (PZT) thin films were deposited on Pt/SiO sub 2 /Si substrates by metal-organic chemical-vapor deposition technique using a solid delivery system to improve the reproducibility of the deposition. The self-regulation mechanism, controlling the Pb-content of the film, was observed to work above a substrate temperature of 620 .deg. C. Even with the self-regulation mechanism, PZT films having low leakage current were obtained only when the molar mixing ratio of the input precursors was 1

  13. Effect of nickel oxide seed layers on annealed-amorphous titanium oxide thin films prepared using plasma-enhanced chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Cheng-Yang; Hong, Shao-Chyang [Institute of Electro-Optical and Materials Science, National Formosa University, Huwei, Yunlin, 63201, Taiwan (China); Hwang, Fu-Tsai [Department of Electro-Optical Engineering, National United University, Miao-Li, 36003, Taiwan (China); Lai, Li-Wen [ITRI South, Industrial Technology Research Institute, Liujia, Tainan, 73445, Taiwan (China); Lin, Tan-Wei [Institute of Electro-Optical and Materials Science, National Formosa University, Huwei, Yunlin, 63201, Taiwan (China); Liu, Day-Shan, E-mail: dsliu@sunws.nfu.edu.tw [Institute of Electro-Optical and Materials Science, National Formosa University, Huwei, Yunlin, 63201, Taiwan (China)

    2011-10-31

    The effect of a nickel oxide (NiO{sub x}) seed layer on the crystallization and photocatalytic activity of the sequentially plasma-enhanced chemical vapor deposited amorphous titanium oxide (TiO{sub x}) thin film processed by a post-annealing process was investigated. The evolution of the crystalline structures, chemical bond configurations, and surface/cross-sectional morphologies of the annealed TiO{sub x} films, with and without a NiO{sub x} seed layer, was examined using X-ray diffractometer, Fourier transform infrared spectrometry, X-ray photoelectron spectroscopy, atomic force microscopy, and field emission scanning electron microscope measurements. Thermo- and photo-induced hydrophilicity was determined by measuring the contact angle of water droplet. Photocatalytic activity after UV light irradiation was evaluated from the decolorization of a methylene blue solution. The crystallization temperature of the TiO{sub x} film, deposited on a NiO{sub x} seed layer, was found to be lower than that of a pure TiO{sub x} film, further improving the thermo- and photo-induced surface super-hydrophilicity. The TiO{sub x} film deposited onto the NiO{sub x} seed layer, resulting in significant cluster boundaries, showed a rough surface morphology and proved to alleviate the anatase crystal growth by increasing the post-annealing temperature, which yielded a more active surface area and prohibited the recombination of photogenerated electrons and holes. The photocatalytic activity of the NiO{sub x}/TiO{sub x} system with such a textured surface therefore was enhanced and optimized through an adequate post-annealing process.

  14. 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.

  15. 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.

  16. Chemical reactions in dense monolayers: in situ thermal cleavage of grafted esters for preparation of solid surfaces functionalized with carboxylic acids.

    Science.gov (United States)

    Dugas, Vincent; Chevalier, Yves

    2011-12-06

    The thermodynamics of a chemical reaction confined at a solid surface was investigated through kinetic measurements of a model unimolecular reaction. The thermal cleavage of ester groups grafted at the surface of solid silica was investigated together with complementary physicochemical characterization of the grafted species. The ester molecules were chemically grafted to the silica surface and subsequently cleaved into the carboxylic acids. A grafting process of a reproducible monolayer was designed using the reaction of monofunctional organosilane from its gas phase. The thermal deprotection step of the ester end-group was investigated. The thermal deprotection reaction behaves in quite a specific manner when it is conducted at a surface in a grafted layer. Different organosilane molecules terminated by methyl, isopropyl and tert-butyl ester groups were grafted to silica surface; such functionalized materials were characterized by elemental analysis, IR and NMR spectroscopy, and thermogravimetric analysis, and the thermodynamic parameters of the thermal elimination reaction at the surface were measured. The limiting factor of such thermal ester cleavage reaction is the thermal stability of grafted ester group according to the temperature order: tert-butyl groups were not selectively cleaved by temperature. The thermal deprotection of i-propyl ester groups took place at a temperature close to the thermal degradation of the organofunctional tail of the silane. The low thermolysis temperature of the grafted tert-butyl esters allowed their selective cleavage. There is a definite influence of the surface on the reaction. The enthalpy of activation is lower than in the gas phase because of the polarity of the reaction site. The major contribution is entropic; the negative entropy of activation comes from lateral interactions with the neighbor grafted molecules because of the high grafting density. Such reaction is an original strategy to functionalize the silica

  17. Guangzhou Chemical Industry%Improvement on the Preparation Method of A Complex [ Co(NH3) 5 Cl] Cl2 for Undergraduate Inorganic Chemistry Experiment

    Institute of Scientific and Technical Information of China (English)

    易正戟; 刘洋; 毛芳芳; 崔莺; 陈满生

    2016-01-01

    Preparation of the coordination compound [ Co ( NH3 ) 5 Cl ] Cl2 is an important inorganic synthesis experiment for the undergraduate Inorganic Chemistry course. However,according to the textbook operation, not only the yield of target product was low and some by-products were produced, but also the volatilization of HCl and NH3 would cause atmosphere pollution. Meanwhile, the target coordination compound detection gave rise to the waste of much valuable reagent AgNO3 . On the basis of green chemistry principle, the key procedure and reagent dosage for the undergraduate Inorganic Chemistry experiment’ for preparing a kind of Co(III) complex were improved. Therefore, the reactant amount of AgNO3 was saved, the yield and purity of the coordination product were increased, and the effect of environmental protection was also achieved.%配位化合物[ Co( NH3)5 Cl] Cl2的制备是大学无机化学课程中一个重要的无机合成实验,但按照教材中的步骤进行操作,不但产率低、易生成其它副产物,而且HCl和NH3气体的挥发容易造成大气污染;同时,目标配合物的检测会造成大量贵重试剂AgNO3的浪费。基于绿色化学理念,针对教材中“一种Co( III)配合物的制备”相关的关键步骤和药品用量进行了改进和创新,节省了AgNO3试剂的用量,提高了产品的产率和纯度,同时也达到了环保的效果。

  18. 化学还原法制备小粒径金纳米粒子%Preparation of Small Size Au Colloid by Chemical Reduction

    Institute of Scientific and Technical Information of China (English)

    丰荣娟; 李敏; 刘家祥

    2013-01-01

    The colloidal gold nanoparticles were prepared by reducing chloroauric acid with NaBH4 in the presence of polyvinyl pyrrolidone (PVP).The influences of the amount of NaBH4 and PVP,reaction temperature and the order of adding NaBH4 on the morphology,particle size and dispersion of the synthesized gold nanoparticles are discussed.The gold nanoparticles' morphology and particle size distribution were characterized by transmission electron microscopy and UV-Vis spectroscopy.The results show that the optimized processing parameters for preparing gold nanoparticles with an average diameter of 4.3nm were worked out,the molar ratio of NaBH4 to chloroauric acid is 3.75∶1; the mass ratio of PVP to chloroauric acid is 1∶1; the reaction temperature is 100℃ ; the NaBH4 is added after chloroauric acid.The ways of influencing factors were explained and the reasons were analyzed.%以聚乙烯吡咯烷酮(PVP)为保护剂,用硼氢化钠还原氯金酸制备出金纳米颗粒,研究了还原剂和保护剂用量、反应温度及试剂加入顺序对金纳米颗粒粒径、形貌、分散性的影响.利用透射电子显微镜和紫外分光光度计对纳米金颗粒的形貌、分散性及尺寸进行表征.结果表明:采用硼氢化钠为还原剂时,硼氢化钠与氯金酸的摩尔比为3.75∶1,PVP与氯金酸的质量比为1∶1,反应温度为100℃并且在氯金酸和PVP的混合溶液中迅速加入硼氢化钠制备的金纳米颗粒均一、平均粒径在4.3nm、分散性好.同时研究了各个影响因素的作用方式并分析了原因.

  19. Single domain SmCo5@Co exchange-coupled magnets prepared from core/shell Sm[Co(CN)6]·4H2O@GO particles: a novel chemical approach.

    Science.gov (United States)

    Yang, Ce; Jia, Lihui; Wang, Shouguo; Gao, Chen; Shi, Dawei; Hou, Yanglong; Gao, Song

    2013-12-20

    SmCo5 based magnets with smaller size and larger maximum energy product have been long desired in various fields such as renewable energy technology, electronic industry and aerospace science. However, conventional relatively rough synthetic strategies will lead to either diminished magnetic properties or irregular morphology, which hindered their wide applications. In this article, we present a facile chemical approach to prepare 200 nm single domain SmCo5@Co core/shell magnets with coercivity of 20.7 kOe and saturation magnetization of 82 emu/g. We found that the incorporation of GO sheets is responsible for the generation of the unique structure. The single domain SmCo5 core contributes to the large coercivity of the magnets and the exchange-coupled Co shell enhances the magnetization. This method can be further utilized in the synthesis other Sm-Co based exchange-coupled magnets.

  20. A study on nano-sized NiO electrodes doping with C and Co prepared by electro-chemical deposition-sintering processes and their capacitance performance

    Institute of Scientific and Technical Information of China (English)

    YU Weiping; YANG Xiaoping; WANG Guangming

    2004-01-01

    In the present work, it was studied that nano-sized NiO electrodes doping with C and Co were prepared by electrochemical deposition in an ethanol solution containing nickel nitrate and cobalt nitrate and sintering processes. The capacitance performance of such electrodes was also studied. The results reveal that samples obtained by electrochemical deposition first on a porous nickel cathode in an ethanol solution contain 0.5 mol/L nitrates, in which Ni(NO3)2 and Co(NO3)2 were mixed in a molar proportion of 8: 2. After sintering at 300℃ for 2 h, they exhibited the best performance. XRD analysis illustrates that the essential phase of the product is NiO doping with certain content of C and Co. The particles of product imaged a spherical morphology with sizes of 20-30 nm in diameter, and with an average crystal size of 4-5 nm. The capacitance measurement of the simulating C/NiO capacitors indicates that a single electrode can reach as high as 410.0 F/g, and still maintain the value of 323 F/g after 30 recycles showed as a stabilized value with increasing recycles, when it was discharged at a current of 5 mA.

  1. Characterization of structure, physico-chemical properties and diffusion behavior of Ca-Alginate gel beads prepared by different gelation methods.

    Science.gov (United States)

    Puguan, John Marc C; Yu, Xiaohong; Kim, Hern

    2014-10-15

    Ca-Alginate beads were prepared with either external or internal calcium sources by dripping technique. It was found that beads synthesized with internal calcium source had a looser structure and bigger pore size than those produced with external calcium source. Consequently, a faster diffusion rate of Vitamin B12 (VB12) within the beads with an internal calcium source was observed. Furthermore, the concentration of calcium ion, ionic strength and pH of the external gel beads formation solution were investigated. Results showed that (a) the concentration of the calcium ion was found to be the determining factor in the gel formation phenomenon; (b) the weight and volume losses are in effect due to water removal; (c) NaCl acts as a competitor with calcium and a screen in the electrostatic repulsion; and (d) the pH controls the gel formation process by regulating the dissociation of alginate and the complexation of the calcium cations. These results are keys to understanding the behavior and performance of beads in their utilization medium.

  2. Microporous Ni@NiO nanoparticles prepared by chemically dealloying Al3Ni2@Al nanoparticles as a high microwave absorption material

    Science.gov (United States)

    Pang, Yu; Xie, Xiubo; Li, Da; Chou, Wusheng; Liu, Tong

    2017-03-01

    The Al3Ni2@Al nanoparticles (NPs) were prepared from Ni45Al55 master alloy by hydrogen plasma-metal reaction method, and were subsequently dealloyed to produce porous Ni@NiO NPs of 36 nm. The pore size ranges from 0.7 to 1.6 nm, leading to large specific surface area of 69.5 m2/g and big pore volume of 0.507 cc/g. The saturation magnetization (MS) and coercivity (HC) of the microporous Ni@NiO NPs are 11.5 emu/g and 5.2 Oe. They exhibit high microwave absorption performance with a minimum reflection coefficient (RC) of -86.9 dB and an absorption bandwidth of 2.6 GHz (RC≤-10 dB) at thickness of 4.5 mm. The enhanced microwave absorption properties are attributed to the synergistic effect of the magnetic Ni core and dielectric NiO shell, and the micropore architecture. The NPs with micropore morphology and core/shell structure open a new way to modify the microwave absorption performance.

  3. Electrical characteristics of mixed Zr-Si oxide thin films prepared by ion beam induced chemical vapor deposition at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Ferrer, F.J., E-mail: fjferrer@us.e [Centro Nacional de Aceleradores (CSIC - U. Sevilla), Av. Thomas A. Edison 7, E-41092 Sevilla (Spain); Frutos, F. [E.T.S. de Ingenieria Informatica, Avda. Reina Mercedes s/n, E-41012 Sevilla (Spain); Garcia-Lopez, J. [Centro Nacional de Aceleradores (CSIC - U. Sevilla), Av. Thomas A. Edison 7, E-41092 Sevilla (Spain); Jimenez, C. [Laboratoire de Materiaux et de Genie Physique, BP 257 - INPGrenoble Minatec - 3 parvis Louis Neel - 38016 Grenoble (France); Yubero, F. [Instituto de Ciencia de Materiales de Sevilla (CSIC - U. Sevilla), c/ Americo Vespucio 49, E-41092 Sevilla (Spain)

    2009-07-31

    Mixed Zr-Si oxide thin films have been prepared at room temperature by ion beam decomposition of organometallic volatile precursors. The films were flat and amorphous. They did not present phase segregation of the pure single oxides. A significant amount of impurities (-C-, -CH{sub x}, -OH, and other radicals coming from partially decomposed precursors) remained incorporated in the films after the deposition process. This effect is minimized if the Ar content in the O{sub 2}/Ar bombarding gas is maximized. Static permittivity and breakdown electrical field of the films were determined by capacitance-voltage and current-voltage electrical measurements. It is found that the static permittivity increases non-linearly from {approx} 4 for pure SiO{sub 2} to {approx} 15 for pure ZrO{sub 2}. Most of the dielectric failures in the films were due to extrinsic breakdown failures. The maximum breakdown electrical field decreases from {approx} 10.5 MV/cm for pure SiO{sub 2} to {approx} 45 MV/cm for pure ZrO{sub 2}. These characteristics are justified by high impurity content of the thin films. In addition, the analysis of the conduction mechanisms in the formed dielectrics is consistent to Schottky and Poole-Frenkel emission for low and high electric fields applied, respectively.

  4. Enhanced photoluminescence and Raman properties of Al-Doped ZnO nanostructures prepared using thermal chemical vapor deposition of methanol assisted with heated brass.

    Directory of Open Access Journals (Sweden)

    Tamil Many K Thandavan

    Full Text Available Vapor phase transport (VPT assisted by mixture of methanol and acetone via thermal evaporation of brass (CuZn was used to prepare un-doped and Al-doped zinc oxide (ZnO nanostructures (NSs. The structure and morphology were characterized by field emission scanning electron microscopy (FESEM and x-ray diffraction (XRD. Photoluminescence (PL properties of un-doped and Al-doped ZnO showed significant changes in the optical properties providing evidence for several types of defects such as zinc interstitials (Zni, oxygen interstitials (Oi, zinc vacancy (Vzn, singly charged zinc vacancy (VZn-, oxygen vacancy (Vo, singly charged oxygen vacancy (Vo+ and oxygen anti-site defects (OZn in the grown NSs. The Al-doped ZnO NSs have exhibited shifted PL peaks at near band edge (NBE and red luminescence compared to the un-doped ZnO. The Raman scattering results provided evidence of Al doping into the ZnO NSs due to peak shift from 145 cm-1 to an anomalous peak at 138 cm-1. Presence of enhanced Raman signal at around 274 and 743 cm-1 further confirmed Al in ZnO NSs. The enhanced D and G band in all Al-doped ZnO NSs shows possible functionalization and doping process in ZnO NSs.

  5. Enhanced Photoluminescence and Raman Properties of Al-Doped ZnO Nanostructures Prepared Using Thermal Chemical Vapor Deposition of Methanol Assisted with Heated Brass

    Science.gov (United States)

    Thandavan, Tamil Many K.; Gani, Siti Meriam Abdul; San Wong, Chiow; Md. Nor, Roslan

    2015-01-01

    Vapor phase transport (VPT) assisted by mixture of methanol and acetone via thermal evaporation of brass (CuZn) was used to prepare un-doped and Al-doped zinc oxide (ZnO) nanostructures (NSs). The structure and morphology were characterized by field emission scanning electron microscopy (FESEM) and x-ray diffraction (XRD). Photoluminescence (PL) properties of un-doped and Al-doped ZnO showed significant changes in the optical properties providing evidence for several types of defects such as zinc interstitials (Zni), oxygen interstitials (Oi), zinc vacancy (Vzn), singly charged zinc vacancy (VZn-), oxygen vacancy (Vo), singly charged oxygen vacancy (Vo+) and oxygen anti-site defects (OZn) in the grown NSs. The Al-doped ZnO NSs have exhibited shifted PL peaks at near band edge (NBE) and red luminescence compared to the un-doped ZnO. The Raman scattering results provided evidence of Al doping into the ZnO NSs due to peak shift from 145 cm-1 to an anomalous peak at 138 cm-1. Presence of enhanced Raman signal at around 274 and 743 cm-1 further confirmed Al in ZnO NSs. The enhanced D and G band in all Al-doped ZnO NSs shows possible functionalization and doping process in ZnO NSs. PMID:25756598

  6. Enhanced photoluminescence and Raman properties of Al-Doped ZnO nanostructures prepared using thermal chemical vapor deposition of methanol assisted with heated brass.

    Science.gov (United States)

    Thandavan, Tamil Many K; Gani, Siti Meriam Abdul; San Wong, Chiow; Md Nor, Roslan

    2015-01-01

    Vapor phase transport (VPT) assisted by mixture of methanol and acetone via thermal evaporation of brass (CuZn) was used to prepare un-doped and Al-doped zinc oxide (ZnO) nanostructures (NSs). The structure and morphology were characterized by field emission scanning electron microscopy (FESEM) and x-ray diffraction (XRD). Photoluminescence (PL) properties of un-doped and Al-doped ZnO showed significant changes in the optical properties providing evidence for several types of defects such as zinc interstitials (Zni), oxygen interstitials (Oi), zinc vacancy (Vzn), singly charged zinc vacancy (VZn-), oxygen vacancy (Vo), singly charged oxygen vacancy (Vo+) and oxygen anti-site defects (OZn) in the grown NSs. The Al-doped ZnO NSs have exhibited shifted PL peaks at near band edge (NBE) and red luminescence compared to the un-doped ZnO. The Raman scattering results provided evidence of Al doping into the ZnO NSs due to peak shift from 145 cm-1 to an anomalous peak at 138 cm-1. Presence of enhanced Raman signal at around 274 and 743 cm-1 further confirmed Al in ZnO NSs. The enhanced D and G band in all Al-doped ZnO NSs shows possible functionalization and doping process in ZnO NSs.

  7. 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.

  8. 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.

  9. Physico-chemical and functional properties of Resistant starch prepared from red kidney beans (Phaseolus vulgaris.L) starch by enzymatic method.

    Science.gov (United States)

    Reddy, Chagam Koteswara; Suriya, M; Haripriya, Sundaramoorthy

    2013-06-05

    The objective of this study was to evaluate the production, physico-chemical and functional properties of Resistant starch (RS) from red kidney bean starch by enzymatic method. Native and gelatinized starch were subjected to enzymatic hydrolysis (pullulanase, 40 U/g/10 h), autoclaved (121 °C/30 min), stored under refrigeration (4 °C/24 h), and lyophilized. The enzymatic hydrolysis and thermal treatment of starch increased the formation of RS which showed an increase in water absorption and water solubility indexes and a decrease in swelling power due to hydrolytic and thermal process. The process for obtaining RS changed the crystallinity pattern from C to B and increased the crystallinity due to the retrogradation process. RS obtained from hydrolysis showed a reduction in viscosity, indicating the rupture of starch molecules. The viscosity was found to be inversely proportional to the RS content in the sample. The thermal properties of RS increased due to the retrogradation and recrystallization (P<0.05).

  10. Production and evaluation of mineral and nutrient contents, chemical composition, and sensory properties of ice creams fortified with laboratory-prepared peach fibre

    Science.gov (United States)

    Yangılar, Filiz

    2016-01-01

    Background In the coming years, a nutraceutical food may provide both physical and mental benefits that are commonly attributed to the active components of the food. Objective In this study, we determined the nutrient and mineral contents, sensory properties, and physical and chemical characteristics of ice creams manufactured using peach fibre at different concentrations (1 and 2%). Method A total of five experimental groups were formed: two types (from peach peel and pulp) of flour, two fibre concentrations (1 and 2%), and a control group without fibres. Results Flour obtained from peach pulp and peel was found to have a significant (pice cream samples, especially the rates of Ca, K, Mg, and P, which increased in the samples depending on the content of peach fibre. Sensory ratings and acceptability of ice creams decreased significantly with increasing peach peel fibre, whereas ice creams made with C (control) and B1 (ice creams made from 1% peach pulp fibre) was the highest scored by the panellists. Conclusions Peach fibre concentrates might be used as a good source of nutraceutical ingredients. PMID:27814781

  11. 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.

  12. 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.

  13. Preparation of liquid chemical feedstocks by co-pyrolysis of electronic waste and biomass without formation of polybrominated dibenzo-p-dioxins.

    Science.gov (United States)

    Liu, Wu-Jun; Tian, Ke; Jiang, Hong; Zhang, Xue-Song; Yang, Guang-Xi

    2013-01-01

    The co-pyrolysis of waste electrical and electronic equipments (WEEEs) and waste biomass to obtain pyrolysis-oil, a liquid fuel or chemical feedstock, was carried out in the present work. The pyrolysis-oil yield of co-pyrolysis reached 62.3% which was significantly higher than those of pyrolysis of WEEEs and biomass alone (i.e., 53.1% for WEEEs and 46.3% for biomass), suggesting that synergistic effects of the WEEEs and biomass happened during the co-pyrolysis process. The pyrolysis-oil mainly contained aromatic compounds, including many aromatic hydrocarbons. More than 90 wt.% of bromides were enriched in pyrolysis-oil and char, which is easily to be recovered by further treatments, and no polybrominated dibenzo-p-dioxins and furans (PBDD/Fs) were detected in all products which may be attributed to the blocking of PBDD/Fs generation under special reductive environment of pyrolysis. This work provided a green and environmentally friendly approach for the disposal of the WEEEs as well as resource recovery.

  14. 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.

  15. 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.

  16. 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.

  17. Study on Preparation of Magnesium Alloy with Chemical Conversion Film Binder Ceramic Coating Bottom%用化学转化膜制备镁合金陶瓷涂层粘结底层研究

    Institute of Scientific and Technical Information of China (English)

    赵斌; 马壮; 张济民; 李欣棉

    2013-01-01

    The conversion of chromate salt, conversion of phosphate and phosphoric acid potassium permanganate conversion were selected to prepare chemical conversion film on magnesium alloy surface. The results indicate that the chromate salt conversion film and conversion of phosphate film on MB2 magnesium surface are un-dense, can not have barrier, shall not be applicable as ceramic coatings transition layers. Preparation of phosphoric acid potassium permanganate conversion film may slow or prevent ceramic pulp with the magnesium substrate for the reaction, be suitable to serve as the ceramic coating transition layers.%选用铬酸盐转化、磷酸盐转化及磷酸-高锰酸钾转化方法制备镁合金表面的化学转化膜.结果表明:在MB2镁合金表面制备的铬酸盐转化膜、磷酸盐转化膜均不够致密,不能起到阻隔作用,均不适合作为陶瓷涂层的过渡层使用;制备的磷酸-高锰酸钾转化膜可以减缓或阻止陶瓷料浆与镁合金基体的反应,适合作为陶瓷涂层的过渡层使用.

  18. Ultrafine WC-Co Composite Powder Preparation by Chemical Precipitation Method%化学沉淀法制备超细WC-Co复合粉的研究

    Institute of Scientific and Technical Information of China (English)

    王玉香; 文小强; 周健

    2012-01-01

    Using ammonium paratungstate and cobalt nitrate as raw materials, ultrafine WC-Co composite powder was prepared by direct reduction&carburization method under the vacuum condition. The effects of feed concentration, reaction temperature and pH value of the mother liquor after reaction on precursor oxide particle size and yield are studied. The morphology and composition of the ultrafine WC-Co composite powder are measured by SEM and XRD. Results show the ultrafine WC-Co composite powder is characterized by regular morphology and good dispersion. This method has advantages of low cost of raw material and simple process.%以钨酸铵和硝酸钴为原料,经化学沉淀后煅烧,然后在真空气氛下直接还原碳化制得超细WC-Co复合粉.考察了化学沉淀过程中料液浓度、反应温度和反应后母液的pH值等因素对所得前驱体氧化物粒度及收率的影响.用XRD和扫描电镜对所得超细WC-Co复合粉进行了分析和观察.结果表明,采用这种方法可以制取形貌规则,分散性良好的超细WC-Co复合粉,并且此法原料成本低,工艺简单,过程易控.

  19. Design and preparation of market baskets of European Union commercial baby foods for the assessment of infant exposure to food chemicals and to their effects.

    Science.gov (United States)

    Piccinelli, R; Pandelova, M; Le Donne, C; Ferrari, M; Schramm, K-W; Leclercq, C

    2010-10-01

    The assessment of acute and chronic dietary exposure to contaminants in baby foods is needed to ensure healthy infant growth. Monthly European Union market baskets of commercial baby foods were designed for the first 9 months of life by the 'babyfood' study group of the CASCADE Network of Excellence for the specific purpose of assessing exposure to potentially toxic substances in infants fed with such foods. The present paper reports the different steps that led to the preparation of monthly pooled samples of commercial baby foods ('Infant formulae and follow-on formulae' and 'Other baby foods') that may constitute the extreme case of the diet for an infant who would not be breast fed at all. Several market baskets were generated for an 'average European Union infant' and for infants of four selected countries (Italy, Sweden, Spain, and the Slovakia), fed with either milk infant formulae, soy infant formulae or hypoallergenic infant formulae and weaned (at the fifth month) with commercial baby foods and beverages available on the European Union market. Market share data for 2007 for baby foods were used to design the baskets. Holding companies and the name of all their products were identified. Monthly diets for European Union infants were elaborated in terms of food categories (e.g. infant cereals) of typologies of products (e.g. infant cereals without gluten) and of a specific product. The number of baskets generated was 30 for 'Infant formulae and follow-on formulae' (including 62 products) and 13 for 'Other baby foods' (including 35 products). These market baskets were designed to be used for the determination of certain contaminants and nutrients in the diet of European Union infants and for the assessment of their effects on infant health.

  20. 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。

  1. 豇豆籽蛋白的制备及理化性质%Preparation and physi-chemical properties of cowpea seed protein

    Institute of Scientific and Technical Information of China (English)

    李安林; 熊双丽; 黄妮

    2011-01-01

    以豇豆籽为原料,采用碱萃取和酸沉淀方法提取分离得到豇豆籽分离蛋白,并采用Osborne法分级制备各类蛋白质。结果发现,豇豆籽分离蛋白必需氨基酸为30.26%,疏水性氨基酸的摩尔比为38.10%,疏水性值为5.01kJ/mol,大于大豆蛋白。其蛋白中清蛋白含量最高(67.56%),其次是谷蛋白(15.32%)和醇溶蛋白(6.65%),球蛋白含量最低(5.43%)。清蛋白和谷蛋白具有较好的持水性质,清蛋白和球蛋白具有较好的持油性。SDS分析各类蛋白质的相对分子质量均在100000~10000Da之间。%The cowpea seed isolated protein was prepared by extraction with alkali solution(pH8.0)and precipitated with hydrochloric acid.It was also fractionated according to Osborne methods.The ratio of total essential amino acids and hydrophobic amino acid in isolated protein were 30.26% and 38.10% respectively.The hydrophobicity values(Q value)of the isolated protein was 5.01kJ/mol,which was higher than that of soybean.In the cowpea seed protein,albumin was the predominant protein fraction(67.56%)followed by glutelin(15.32%),prolamin(6.65%)and globulin(5.43%).Albumin and glutelin had better water-holding capacities.Albumin and globulin had better oil-holding capacities.The results of SDS-PAGE exhibited that the molecular weight of the fractions were between 100000Da and 10000Da.

  2. 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

  3. 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

  4. 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…

  5. Chemical Analyses

    Science.gov (United States)

    Bulluck, J. W.; Rushing, R. A.

    1994-01-01

    As a preliminary study on the effects of chemical aging of polymer materials MERL and TRI have examined two polymeric materials that are typically used for offshore umbilical applications. These two materials were Tefzel, a copolymer of ethylene and tetrafluoroethylene, and Coflon, polyvinylidene fluoride. The Coflon specimens were cut from pipe sections and exposed to H2S at various temperatures and pressures. One of these specimens was tested for methane permeation, and another for H2S permeation. The Tefzel specimens were cut from .05 mm sheet stock material and were exposed to methanol at elevated temperature and pressure. One of these specimens was exposed to methanol permeation for 2 days at 100 C and 2500 psi. An additional specimen was exposed to liquid methanol for 3 days at 150 C and 15 Bar. Virgin specimens of each material were similarly prepared and tested.

  6. 不同络合剂对化学镀法制备镍包铜复合粉末的影响%Effect of different complexing agents on nickel-coated copper compound powder prepared with chemical plating

    Institute of Scientific and Technical Information of China (English)

    王玉棉; 孙建国; 赵忠兴; 徐瑞

    2013-01-01

    利用化学镀的方法制备镍包铜复合粉末,考察柠檬酸钠、醋酸钠和乳酸3种络合剂对Ni/Cu包覆粉体的转化率、包覆效果及分散性的影响.分别采用扫描电子显微镜、EDS能谱仪、X射线衍射仪对镍包铜粉末的微观形貌和物相组成进行表征.结果表明:采用柠檬酸钠作为络合剂能使镍更好地包覆于铜粉表面,镍金属原子分数大于90%,并且具有良好的分散性.%Using the chemical plating method,the nickel-coated copper composite powder was prepared,and the effect of three complexing agents of sodium citrate,sodium acetate,and lactic acid on the conversion,coating and dispersion of Ni/Cu cladding powder was examined.The microstructure and compositions of nickel-coated copper powder were characterized by means of scanning electron microscope,EDS energy spectrometer and X ray diffractometer respectively.The result showed that,using sodium citrate as complexing agent,the best nickel-coated copper powder could be prepared,and the atomic percentage content of nickel could reach more than 90%,and had good dispersity.

  7. 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+).

  8. 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.

  9. Study on Preparation and Chemical Characterization of IRON ( Ⅲ ) - Polygonatum odoratum Polysaccharides Complex%玉竹多糖铁的制备及其理化性质研究

    Institute of Scientific and Technical Information of China (English)

    许丽丽; 展晓日; 曾昭武; 李霞; 王淑玲; 谢恬

    2012-01-01

    OBJECTIVE To prepare Polygonatum odoratum polysaccharide-iron ( Ⅲ) complex (POPFe) and study its physico-chemical properties. METHODS POPFe was synthesized by neutralization of FeCl3 carbohydrate solution. Orthogonal design was used to optimize the preparation process. The content of iron ( Ⅲ) in POPFe was determined with o-phenanthroline spectrophotometry and iodometry. The surface structure of POPFe was studied by infrared spectroscopic technique. The deoxidization of POPFe was tested with colorimetric analysis. RESULTS The optimal preparation conditions were found as follows: the ratio of polysaccharides aqueous solution to sodium citrate solution as 4: 1, temperature 70 ℃ and pH 8 - 9. POPFe showed qualitatively identified reactions of Fe ( Ⅲ ). The content of Fe ( Ⅲ ) in POPFe was 30. 13%. The complex was stable at pH 3 - 12 without precipitation and dissociatioa At 37 ℃, Fe ( Ⅲ ) in the complex was completely reduced to Fe ( Ⅲ ) by ascorbic acid in about 5 h. CONCLUSION POPFe can be developed as a new iron supplementary.%目的 研究玉竹多糖铁(POPFe)配合物的合成方法及药用性能.方法 采用微波萃取技术提取浙产玉竹中多糖,以玉竹多糖和三氯化铁为底物正交实验设计合成POPFe配合物,借助邻菲啰啉分光光度法和置换碘量法测定铁含量,通过红外光谱法对其进行了结构表征,并探讨了POPFe在水溶液中的稳定性及生理条件下释放铁的可能性.结果 POPFe最佳合成条件是多糖水提液与柠檬酸三钠的体积比4∶1,温度70℃,pH 9.在该条件下所得无定形黄棕色粉末,易溶于水,铁的质量分数为30.13%,其水溶液在pH值3~12内稳定.以抗坏血酸还原POPFe,铁在5h内基本溶出.结论 POPFe是聚合多糖与多聚铁核形成的配合物,有望开发为新型补铁剂.

  10. 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 ...

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 镁合金表面钇盐化学转化膜的制备与表征%Preparation and characterization of yttrium-based chemical conversion coating for magnesium alloys

    Institute of Scientific and Technical Information of China (English)

    李玲莉; 杨雨云; 赵刚; 崔秀芳

    2012-01-01

    为了拓展稀土元素的应用范围,丰富稀土化学转化膜的门类,采用SEM,XPS和EDS等表面分析技术结合电化学分析测试技术,探索在镁合金表面制备新型稀土转化膜——钇盐化学转化膜,分析其形貌、化学组成及耐腐蚀性,并对其成膜机理进行初步的探讨.结果表明,采用文中工艺,可在镁合金表面成功制备覆盖完整具有均匀微裂纹的钇盐化学转化膜.转化膜主要化学组成物组为Y2O3,YOX/Y,MgO和少量的Al2O3.主要成膜元素Y和Mg在膜层与基体界面区域分别呈现递增和递减的现象.电化学测试结果表明,钇盐转化膜可以明显提高镁合金的耐腐蚀性,是一种值得深入发展和研究的新型稀土化学转化膜.%In an effort to expand the application scope of rare earth mineral and at the same time enrich the categories of rare earth chemical conversion coating, a new preparation called yttrium based chemical conversion coating for magnesium alloys study is proposed. The micromorphology, elemental chemical states and corrosion resistance were observed by the surface analysis technologies of SEM, XPS and EDS combined with the electrochemical analysis and testing technology , respectively. The literature review reveals a preliminary study on the new procedure for conversion coating formation mechanism has been done previously. The research results indicate the yttrium-based conversion coating with uniformly distributed micro cracks has formed on the surface of magnesium alloys successfully. The EDS and XPS results reveal, the coating is primarily made of MgO, Y2O3, YO X/Y and a small amount of Al2O3. During the observation of the coating and substrate interface regions, the results suggest, the main two components of the coating had a content increment of element Y and a content decrement of element Mg. The result from the electrochemical analysis and testing proves that yttrium-based conversion coating is a new type of rare earth

  18. 单宁酸磷脂复合物的制备及其理化性质研究%Study on preparation and physic-chemical properties of tannic acid-phospholipid complex

    Institute of Scientific and Technical Information of China (English)

    吴春; 冯海波

    2015-01-01

    Preparation of tannic acid -phospholipid complex was studied using tannic acid and soybean lecithin as materials .The effects of reactive temperature , reactive time , con-centration of react-ants and the ratio of reactants on preparation were investigated using sin-gle factor experiment , the optimal reaction conditions were determined by orthogonal test , and the physic -chemical properties of tannic acid -phospholipid complex and solubility were examined .The optimized conditions were obtained as follows:the reactive temperature was 60 ℃;the reactive time was 1.5 h;the concentration of reactants was 4 mg/mL, and the ratio of tannic acid to phospholipid was 2∶1 .IR and UV spectroscopic analysis showed that tannic acid and phospholipids did not form a new compound but a kind of complex com-bine through intermolecular force .Compared with tannic acid , solubility in water redused , but the octanol solubility improved obviously .%以单宁酸和大豆卵磷脂为原料制备单宁酸磷脂复合物.以单宁酸与磷脂的复合率为评价标准,通过单因素实验考察反应温度、反应时间、反应物初始质量浓度和投料比例对复合率的影响,由正交试验得到最优条件.研究了单宁酸磷脂复合物的理化性质及溶解性能.结果表明,单宁酸磷脂复合物的最佳制备工艺为:以乙醇为反应溶剂,反应温度为60℃,反应时间为1.5 h,单宁酸质量浓度为4 mg/mL,投料质量比例为2∶1.红外光谱和紫外光谱分析表明,单宁酸与磷脂未形成新的化合物而是通过分子间作用力形成的复合物.与单宁酸相比,复合物在水中溶解度有所降低,但在正辛醇中溶解性有明显改善.

  19. 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.

  20. 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

  1. 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.

  2. Characterization and study of reduction and sulfurization processing in phase transition from molybdenum oxide (MoO2) to molybdenum disulfide (MoS2) chalcogenide semiconductor nanoparticles prepared by one-stage chemical reduction method

    Science.gov (United States)

    Shomalian, K.; Bagheri-Mohagheghi, M.-M.; Ardyanian, M.

    2017-01-01

    In this research, molybdenum disulfide (MoS2) nanoparticles were prepared by chemical reduction method using MoO3 and thiourea as a precursor. The physical properties of the synthesized MoO2-MoS2 nanoparticles annealed at different temperatures of 200, 300, 750 °C have been investigated, before and after exposure to sulfur vapor. The nanostructure of nanoparticles has been characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM) analyses and UV-Vis spectrophotometer. The X-ray diffraction analysis showed the formation of MoS2 single phase at annealing temperature of 750 °C in the presence of sulfur vapor. The Raman spectrum of the nanoparticles revealed that the formation of MoS2 at 750 °C after annealing in sulfur vapor. The values of band gap were obtained in the range of 3.64-3.17 eV and 3.47-1.95 eV for MoS2 nanoparticles before and after exposure to sulfur vapor, respectively. According to SEM images, the grain size decreases with increasing annealing temperature up to 750 °C. Also, nanoplate-nanoparticles of MoS2 are formed at annealing temperature of 200-750 °C. The TEM images of MoS2 nanoparticles at T a = 750 °C confirm that the nanoparticles have a homogeneous distribution with a hexagonal structure. The FTIR spectra of the MoS2 nanoparticles showed the peaks at about 467 cm-1 belong to the characteristic bands of Mo-S.

  3. Research of zinc oxide quantum dot light-emitting diodes based on preparation of chemical solutions%基于化学溶液法制备的氧化锌量子点发光二极管研究

    Institute of Scientific and Technical Information of China (English)

    孙义; 李青

    2016-01-01

    氧化锌(ZnO)量子点是一种宽直接带隙半导体纳米颗粒,具有激子束缚能大、绿色环保、量子效应等优点,引起广泛关注。近期,将通过化学溶液法制备的 ZnO 量子点应用到发光二极管的研究成为热点。文章综述了近几年 ZnO 量子点发光二极管研究进展,重点介绍了各种结构的 ZnO 量子点发光二极管最新研究成果,并对 ZnO 量子点发光二极管的发展趋势进行了展望。%Zinc oxide (ZnO)quantum dot is a kind of wide direct band gap semiconductor nanoparticle, with many advantages,e.g.,larger exciton binding energy,environmental friendly,quantum effects, which has attracted a number of attentions.Recently,the ZnO quantum dots prepared through chemi-cal solutions was applied more actively in the study of light emitting diodes.The review describes the achievements in the field of ZnO quantum dot light emitting diode in recent years.We concentrate on the current achievements and problems of the ZnO quantum dot light emitting diode of various struc-tures,and the development trend of ZnO quantum dot light emitting diodes in the future.

  4. 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.

  5. 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

  6. 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

  7. Brittleness of 6.5wt% Si Silicon Steel Prepared by Chemical Vapor Deposition Method%化学气相沉积法制备硅质量分数6.5%硅钢的脆性

    Institute of Scientific and Technical Information of China (English)

    高超; 苏芳臣; 相颖杰; 孙权; 陈建钧

    2015-01-01

    6.5wt% Si silicon steel was prepared by chemical vapor deposition (CVD)method and the effects of reaction temperature,oxygen content in atmosphere and SiCl4 content on the brittleness of 6.5wt%Si silicon steel were studied using SEM,EDS and self-developed three-point bending machine.The results show that the grain size of the silicon steel increased with the reaction temperature rising,and the brittleness of the silicon steel increased with the increase of the grain size.Grain boundary oxidation was observed in the silicon steel when oxygen content in atmosphere was 100 mg·kg-1 ,which increased the brittleness of the silicon steel.Kirkendall voids were found in the silicon steel with a relatively high SiCl4 content of 35vol%,which increased the brittleness of the steel.%采用化学气相沉积(CVD)法制备了硅质量分数为6.5%的硅钢,利用扫描电镜、能谱仪和自主设计研发的三点压弯机研究了反应温度、气氛含氧量和 SiCl4含量对硅钢脆性的影响.结果表明:硅钢的晶粒尺寸随反应温度的升高而长大,硅钢的脆性随着晶粒尺寸的增加而增大;气氛含氧量在100 mg·kg-1时所制备的硅钢产生了晶界氧化现象,使硅钢脆性增加;SiCl4含量较大时(体积分数35%)所制备的硅钢产生了 Kirkendall 空洞,导致其脆性加剧.

  8. Precipitation and ultimate pH effect on chemical and gelation properties of protein prepared by isoelectric solubilization/precipitation process from pale, soft, exudative (PSE)-like chicken breast meat.

    Science.gov (United States)

    Zhao, X; Xing, T; Chen, X; Han, M-Y; Li, X; Xu, X-L; Zhou, G-H

    2016-11-11

    Pale, soft, exudative (PSE)-like chicken breast is considered deteriorated raw material in the poultry meat industry that has inferior processing ability. The chemical and gelation properties of PSE-like chicken breast meat paste were studied. These pastes were prepared by the pH adjustment method and protein isolation using the isoelectric solubilization/precipitation (ISP) process from PSE-like chicken meat. The ISP-isolated samples were solubilized at pH 11.0 and recovered at pH 5.5 and 6.2. The ultimate pH of the ISP-isolated protein and meat paste was adjusted to 6.2 and 7.0. The ultimate pH in this article referred to the final pH of the extracted protein and meat paste. Higher reactive sulfhydryl content and surface hydrophobicity were found in the precipitation at pH 6.2 than at pH 5.5. However, various ultimate pH values showed no significant influence on the surface hydrophobicity. The hardness of gel, as measured by textural profile analysis, was improved using 6.2 as the precipitation pH compared with pH 5.5. The viscoelastic modulus (G(')) of gel pastes prior to the thermal gelation was higher with ISP treatment. However, lower G(') was seen after thermal gelation compared with the control. Dynamic rheological measurement demonstrated a different gel-forming mechanism for protein precipitated at pH values of 5.5 and 6.2 compared with the meat paste. The cooking loss showed that the recovered protein failed to form a gel with good water-retention capacity unless the ultimate pH was adjusted to 7.0. Gels made from protein extracted by the ISP method had higher yellowness and lower redness values, probably due to protein denaturation. Precipitation at pH 6.2 formed a harder gel with lower water-retention ability than that at pH 5.5, and this result was possibly due to higher surface hydrophobicity and S-S bridge formation. Overall, network characteristics of ISP-treated protein gels were strongly dependent on precipitation pH and ultimate pH.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. 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。

  15. 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...

  16. 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)

  17. 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...

  18. 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)

  19. Preparation and characterization of the lightweight concrete produced by H2 O2 chemical foaming in situ%H2 O2原位发泡轻混凝土的制备与性能表征∗

    Institute of Scientific and Technical Information of China (English)

    樊传刚; 吴瑞; 黄兴田; 陈贺; 孟方方; 李家茂

    2016-01-01

    The lightweight concrete (LC)specimens were prepared using the method of chemical foaming in situ. In the foaming process,the H2 O2 was used as foaming agent,the coarser and fine expanded perlites were used as lightweight aggregate and as carrier for H2 O2 respectively,and the gelatin was used as foam stabilizer.The foaming reaction of H2 O2 was taken place after it was being charged into carriers and the charged carriers were mixed into the mortar previously.The mortar was enclosed by the lightweight aggregates in fresh concrete.The properties of the resulting LC specimens were characterized systemically.It was found that the adding amount of 1.5wt% foam stabilizer had the promising stabilization for the foam formed in situ,which resulted in the bubbles with 0.5-1 mm diameter in homogeneous distribution.The bulk densities (BD)of resulting LC speci-mens were decreased with the increasing of the adding amount of foaming agent,and increased with the adding amount of foam stabilizer.For the resulting LC specimens with foam stabilizer amount of 1.5wt%,their 28 d compressive strengths (CS)and thermal conducting coefficients (TCC)were decreased with the increase of the amount of foaming agent.Among them,the resulting LC specimen with foaming agent of 1.4wt% had the 28 d CS of 21 MPa and the BD of 940 kg/m3 .As compared with that of the resulting LC specimen without foaming agent,its specific strength value was improved by 14% and its TCC was decreased by 13%,respectively.%以 H2 O2溶液(质量浓度30%)为发泡剂,粗、细膨胀珍珠岩颗粒为轻集料和发泡剂载体,明胶为稳泡剂,采用将加载发泡剂的载体拌入轻集料混凝土的水泥浆中原位化学发泡的方法,制备出了系列轻混凝土试样,并对其性能进行了系统表征.结果表明,原位发泡轻混凝土中外加1.5%(质量分数)胶凝材料量的稳泡剂后,对气泡有较为理想的稳泡作用,可获得均匀分布的细小气泡(气泡直径0.5~1 mm).原位

  20. Preparation of blue pigment extract from pickled garlic and its physio-chemical properties%绿变大蒜蓝色素的制备及理化活性

    Institute of Scientific and Technical Information of China (English)

    赵晓丹; 李星

    2014-01-01

    为了进一步明确大蒜绿变物质的结构及性质,该研究对绿变产物进行分离制备并探索了其相关理化活性。从绿变大蒜中提取出绿变产物,并通过AmberliteCG-50和SephadexLH-20两步纯化制备得到了蓝色素的纯化产品,其色价为76.7。对色素的理化性质进行了研究,结果表明蓝色素在酸性条件pH值<7时稳定;对热处理也比较稳定,60℃以下加热处理对色素影响较小;长时间的日光照射会使蓝色素有较大的损失;一些常见的金属离子Cu2+、Zn2+、Al3+、Fe2+的存在对蓝绿色素几乎没有影响,Fe3+的存在会使色素迅速褪色。蓝色素对自由基有清除效果:质量浓度为2 mg/mL的蓝色素提取物对1,1-二苯基-2-三硝基苯肼(DPPH)清除率达到96.4%;在10 mg/mL质量浓度下,蓝色素对超氧和羟基自由基的清除率分别为96.8%和87.6%;色素提取物对自由基的清除效果低于同浓度的抗坏血酸。该研究结果对深入研究绿变色素的性质和结构奠定了初步基础。%The greening compounds in garlic are of great importance to both industry and academic research. In this study, the blue pigment extract in greening garlic has been prepared and its physio-chemical properties and scavenging activities towards DPPH radicals, superoxide anion radicals and hydroxyl radicals have been investigated. The blue pigments in Laba garlic were extracted and separated by chromatography with Amberlite CG-50 and Sephadex LH-20, and the blue pigment extract (BPE) was obtained. Color value of BPE was elevated to 76.7 compared to 10.7 that of the raw extract without any purification. BPE was stable in acidic conditions, but sensitive to illumination. Low-temperature heating (lower than 60 2℃+,)Zhna2d+,lAittl3e+,eFffe2c+thoandthliettlsetaebfifleictyt onfBthPeE.M etalionssuch as pigment stability, but Fe3+ caused obvious color loss. The BPE displayed concentration-dependent inhibition of 1,1-diphenyl

  1. How Prepared is Prepared Enough?

    Science.gov (United States)

    Porter-Levy; Macleod; Rickert

    1996-10-01

    A 17-year-old female was in the final stage in treatment of right unilateral cleft lip and palate. She had undergone a number of previous surgeries. Hearing and speech were good on evaluation, and her social and family situation were deemed excellent. After preparatory orthodontics she underwent a Lefort I maxillary advancement. Surgery was successful and she was admitted into postoperative recovery. However, the lack of adequate preoperative preparation caused traumatic reaction from the patient and her parents: anxiety over appearance, crying, refusal of oral fluids and oral care, refusal of analgesia, and refusal to mobilize. The patience and persistence of hospital staff slowly overcame all adversities and the patient moved on to full and successful recovery, but this case prompted changes in preoperative procedures and involvement of patients and their families in postoperative meal selection, planing, and preparation.

  2. 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.

  3. 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.

  4. Preparation of zeolite covered cellulose fibers

    Energy Technology Data Exchange (ETDEWEB)

    Mintova, S.; Valtchev, V. [Institute of Applied Mineralogy, Sofia (Bulgaria)

    1995-12-01

    Membrane separation has proved to be an important technology in chemical industry. That is why the design of different type of zeolite containing membranes has received much attention during the last decade. Zeolite containing filters and membranes were prepared by embedding zeolite crystals with adhesive substances in the cellulose matrix. This communication discussed the preparation of zeolite containing cellulose materials by in situ crystallization. Discussed axe: (1) the effect of the vegetal fiber structure and chemical composition (2) the effect of the type of the zeolite coating; (3) the effect of the mechanical and chemical treatment of the fibers on the process of the fiber zeolite coating.

  5. 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.

  6. A Comparison between Chemical Synthesis Magnetite Nanoparticles and Biosynthesis Magnetite

    OpenAIRE

    2014-01-01

    The preparation of Fe3O4 from ferrous salt by air in alkaline aqueous solution at various temperatures was proposed. The synthetic magnetites have different particle size distributions. We studied the properties of the magnetite prepared by chemical methods compared with magnetotactic bacterial nanoparticles. The results show that crystallite size, morphology, and particle size distribution of chemically prepared magnetite at 293 K are similar to biosynthesis of magnetite. The new preparation...

  7. Chemical intolerance

    DEFF Research Database (Denmark)

    Dantoft, Thomas Meinertz; Andersson, Linus; Nordin, Steven;

    2015-01-01

    Chemical intolerance (CI) is a term used to describe a condition in which the sufferer experiences a complex array of recurrent unspecific symptoms attributed to low-level chemical exposure that most people regard as unproblematic. Severe CI constitutes the distinguishing feature of multiple...... 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...

  8. 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.

  9. A New Paradigm for Chemical Engineering?

    DEFF Research Database (Denmark)

    Gani, Rafiqul

    businesses has been observed. There is an increasing trend within the chemical industry to focus on products and the sustainable processes that can make them. Do these changes point to a paradigm shift in chemical engineering as a discipline? Historically, two previous paradigm shifts in chemical engineering...... corresponded to major shifts in chemical engineering as a discipline, which affected not only the education of chemical engineers, but also the development of chemical engineering as a discipline. Has the time come for a new paradigm shift that will prepare the current and future chemical engineering graduates...... to tackle the complex problems facing the chemicals based industries and serve the modern society more efficiently? The lecture will review the current status of chemical engineering as a discipline, the proposals for the third paradigm, the need for such a paradigm shift and related educational issues....

  10. Super water repellent finishing technology by simulating bio-structures. Improvement of chemical durability by super water repellent finishing of hydroxy- apatite/titan composite films prepared by high-frequency plasma arc spraying; Seibutsu no kozo wo mohoshita chohassuika gijutsu. Koshuha plasma yoshaho ni yori sakuseishita suisan apataito/chitan fukugo himaku no chohassuika ni yoru kagakuteki taikyusei no kojo

    Energy Technology Data Exchange (ETDEWEB)

    Hozumi, A.; Inagaki, M.; Okuderaa, H.; Nishizawa, K.; Nagata, F.; Teraoka, H.; Yokogawa, Y.; Kameyama, T. [National Industrial Research Institute of Nagoya, Nagoya (Japan)

    2000-08-25

    Artificial joint and tooth root produced by coating hydroxy- apatite (HA) onto Ti alloy base surface by DC plasma torch arc spraying in commercially available in Europe, and have been used for persons not less than 100,000 since 1985. However, peeling and dissolution of coats after implant have been reported as a serious problem. The long-term stability of coats is dependent on the chemical durability of coats. Paying attention to physical structure of HA/Ti composite film surface. this study attempted super water repellent finishing of the surface through reduction of surface energy by chemical modification of the surface in a molecular level. Self-organization single-molecule film of organic silane compound with perfluoroalkyl group was formed by CVD on the HA/Ti composite film surface prepared on Ti alloy by high- frequency plasma arc spraying. The extremely hydrophobic HA/Ti composite film with a contact angle ranging 130-160 degrees was thus obtained from the highly hydrophilic coat. This sample showed a very high chemical durability as compared with conventional ones. (NEDO)

  11. 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

  12. A Chemical Technology Program Partnership

    Science.gov (United States)

    Hicks, Gary

    1998-01-01

    Brazosport College would be the first to admit that they owe the success of their Chemical Technology Program to the partnership that was developed between the college and the surrounding chemical industry. The college is a two-year institution located near the Texas Gulf Coast with more than twelve chemical companies in the immediate area. Dow Chemical is the largest, employing more than 5,000. Currently, the Science Department at Brazosport College offers associate of science degrees in biology, chemistry, and physics, and associate of applied science degrees in chemical technology and instrumentation technology to meet the needs of these industries. In addition, many students enroll in classes to prepare for specific occupations or to build their skills for employment. This may only require the student to take a few courses. The current Chemical Technology Program addresses skills needed for both laboratory and process technician jobs in the chemical industry. An Associate of Applied Science Degree in Chemical Technology is offered with either a laboratory or a process option. These programs were developed with input from the chemical industry, and the college trains all new process employees for BASF and Dow. Additionally, the college does customized flexible-entry training in process operations and laboratory analysis for these and several other companies.

  13. 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.

  14. 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.

  15. 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)

  16. Nanoscale porosity in pigments for chemical sensing

    OpenAIRE

    Kemling, Jonathan W.; Suslick, Kenneth S.

    2011-01-01

    Porous pigments in which chemically responsive dyes have been immobilized in a matrix of organically modified siloxanes (ormosils) have been prepared and characterized by AFM, TEM, EDS, and optical analysis. In typical chemical sensing applications, an array of 36 different porous ormosil pigments are deposited on polyethylene terephthalate (PET) film.

  17. Nanoscale porosity in pigments for chemical sensing.

    Science.gov (United States)

    Kemling, Jonathan W; Suslick, Kenneth S

    2011-05-01

    Porous pigments in which chemically responsive dyes have been immobilized in a matrix of organically modified siloxanes (ormosils) have been prepared and characterized by AFM, TEM, EDS, and optical analysis. In typical chemical sensing applications, an array of 36 different porous ormosil pigments are deposited on polyethylene terephthalate (PET) film.

  18. 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…

  19. 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

  20. Preparing for Surgery

    Science.gov (United States)

    ... Events Advocacy For Patients About ACOG Preparing for Surgery Home For Patients Search FAQs Preparing for Surgery ... Surgery FAQ080, August 2011 PDF Format Preparing for Surgery Gynecologic Problems What is the difference between outpatient ...

  1. 普洱茶熟茶茶膏的制备及主要成分分析%Preparation of Fermented Pu' er Tea Cream and Principal Chemical Compositions Analysis

    Institute of Scientific and Technical Information of China (English)

    陈迪; 杨柳

    2012-01-01

    The preparation of fermented Pu' er lea cream was carried out using vacuum concentration and bath concentration, and the nutrient component and phenolic compounds in Pu' er tea cream were analyzed and determined, which includes tea polyphenols, total catechins, mon-omeric catechins, protein, amino acids, polysaccharides, total sugar and dry matters. The results showed that the content of vacuum drying fermented Pu' er tea cream, overall catechins, polyphenols, protein, dry matters and catechin monomers were lower than those made by bath concentration of dry fermented Pu' er tea cream. Especially the content of EGCG was particularly significant. While the use of vacuum concentration to prepare the Pu' er tea cream, the content of polysaccharides and total sugar were higher than those by the concentrated tea extract with water bath. The research provides a more reliable experimental guidance and theoretical basis for the industrial production and application of fermented Pu' er tea cream.%采用真空浓缩和水浴浓缩2种方法完成了普洱熟茶茶膏的制备,并对普洱熟茶茶膏的营养成分、酚类物质进行分析测定,包括茶多酚、总儿茶素、单体儿茶素、蛋白质、氨基酸、多糖、总糖和干物质的含量.结果表明,采用真空浓缩的普洱熟茶茶膏的总体儿茶素、茶多酚、蛋白质、干物质含量以及单体儿茶素含量都高于采用水浴浓缩的普洱熟茶茶膏中这些成分的含量,尤其是表没食子儿茶素没食子酸酯(EGCG)的含量尤为显著,而采用真空浓缩的普洱熟茶茶膏的多糖及总糖含量却低于采用水浴浓缩茶膏的多糖和总糖含量.研究为工业生产中普洱熟茶茶膏的制作与应用提供了较为可靠的试验指导和理论依据.

  2. Chemical preparation and thermal behavior of neodymium cyclotriphosphate pentahydrate NdP{sub 3}O{sub 9}.5H{sub 2}O: A study by Controlled Rate Thermal Analysis (CRTA)

    Energy Technology Data Exchange (ETDEWEB)

    Nahdi, Kais [Laboratoire d' Application de la Chimie aux Ressources et Substances Naturelles et a l' Environnement, Faculte des Sciences de Bizerte, Departement de Chimie, 7021 Zarzouna, Bizerte (Tunisia)], E-mail: k_nahdi@yahoo.fr; Ferid, Mokhtar; Ayadi, Malika Trabelsi [Unite de Materiaux de Terres Rares, Centre National de Recherches en Sciences des Materiaux, BP 95, Hammam-Lif, 2050 (Tunisia)

    2009-04-10

    A new neodymium cyclotriphosphate pentahydrate powder, NdP{sub 3}O{sub 9}.5H{sub 2}O, has been prepared using a classical chemistry method and characterized by X-ray diffraction and infrared spectroscopy techniques. The IR spectrum shows the characteristic bands of cyclotriphosphates as the triplet in the range 1055-1007-917 cm{sup -1}. The thermal behavior of the titled compound was also carried out using conventional thermal analysis techniques (TG and DSC) under air atmosphere and Controlled transformation Rate Thermal Analysis (CRTA) technique under constant water vapour pressure of 5 hPa. It was shown that thermal treatment in air, with linear heating rate of 10 K min{sup -1}, favourites the structure breakdown as soon as the release of water molecules starts. In this case an amorphous compound is obtained, which then crystallizes at 1073 K and gives the polyphosphate Nd(PO{sub 3}){sub 3}. However, by CRTA technique at P{sub H{sub 2}}{sub O}=5hPa, the water molecules are eliminated with a lower rate which permits to save the initial structure up to an advanced dehydration step. The breakdown of the initial structure is immediately followed by the crystallization of the anhydrous polyphosphate Nd(PO{sub 3}){sub 3} phase in the temperature range 455 K < T < 793 K.

  3. Preparation and Characterization for Permanganate Chemical Conversion Film on LY12 Aluminum Alloy%LY12铝合金的锰酸盐导电化学转化膜制备与表征

    Institute of Scientific and Technical Information of China (English)

    吴友恒; 黎学明; 杨文静; 高丽

    2011-01-01

    Prepartion technology of promanganate chemical anversion film on LY12 alaminum alloy was studied with main salt KM. nO4 and accelerator Na2 ZrF6. The corrosion resistance and conductivity of conversion film were tested by the dropping test and the contact resistance method, respectively. The film morphology, composition and structure were analyzed by SEM/EDS and XRD. A possible formation mechanism for permanganate conversion film was proposed. The results show that the best component of chemical conversion bath is 5 g/L KMnO4 and 0.05 g/L Na2ZrF6,while the pH value is 2.0 at 65 ℃ for 60s and the time of post treatment is 30 min in boiling water. The layer is uniform and compact, which is composed of Al,(), Mn elements. The corrosion resistance and conductivity of the conversion film increase obviously. The time of corrosion resistance is 57 seconds and the contact resistance of the conversion film is just 15.6% of the unconverted aluminum alloy.%以KMnO4为主盐,Na2ZrF6作促进剂,研究了LY12铝合金锰酸盐化学转化膜的制备工艺,采用点滴法和膜接触电阻法评价转化膜的耐蚀性和导电性,并用SEM,EDS和XRD表征转化膜的形貌与组成,进而探讨成膜机理.结果表明:当KMnO4的质量浓度为5 g/L,Na2ZrF6的质量浓度为0.05 g/L,pH值2.0,温度65℃,转化时间60 s、沸水后处理30 min时,所制备的锰酸盐转化膜颜色呈金黄色,该膜层均匀、致密,主要成分为Al,O,Mn元素,由铝和锰的氧化物组成.LY12铝合金表面的锰酸盐化学转化膜耐蚀性和导电性明显提高,点滴法耐腐蚀时间达到57 s,转化膜表面接触电阻仅为铝合金基体接触电阻的15.6%.

  4. 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)…

  5. 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.

  6. Characterization of RuO sub 2 electrodes for ferroelectric thin films prepared by metal-organic chemical-vapor deposition using Ru(C sub 1 sub 1 H sub 1 sub 9 O sub 2) sub 3

    CERN Document Server

    Lee, J M; Shin, J C; Hwang, C S; Kim, H J; Suk, C G

    1999-01-01

    Pure and conducting RuO sub 2 thin films were deposited on Si substrates at 250 approx 450 .deg. C using Ru(C sub 1 sub 1 H sub 1 sub 9 O sub 2) sub 3 as a precursor by low-pressure metal-organic chemical-vapor deposition (LP-MOCVD). At a lower deposition temperature,smoother and denser RuO sub 2 thin films were deposited. The RuO sub 2 thin films, which were crack free, adhered well onto the substrates and showed very low resistivities around 45 approx 60 mu OMEGA cm. RuO sub 2 thin films on (Ba, Sr)/TiO sub 3 /Pt/SiO sub 2 /Si showed good properties, indicating that MOCVD RuO sub 2 thin films from Ru(C sub 1 sub 1 H sub 1 sub 9 O sub 2) sub 3 can be applied as electrodes of high-dielectric thin films for capacitors in ultra-large-scale DRAMs.

  7. 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)

  8. 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.

  9. Prepareation on Curdlan Modified by Sulphonic Acid and Study on its Physical and Chemical Properties%可德胶的磺酸化改性及产物物化性能的研究

    Institute of Scientific and Technical Information of China (English)

    钱涛涛; 何欣芝; 梁洒洒; 潘泉泉; 孙燕

    2012-01-01

    为了提高可德胶的水溶性,对其进行磺酸化改性研究。本实验是在氮气保护下,以二甲亚砜作溶剂,选择不同水浴温度(如:40℃、50℃、60℃、70℃)下持续搅拌9h,然后加入O.5g三氧化硫一吡啶,继续搅拌2h后,用0.5mol/L的NaOH中和后于去离子水中进行透析,最后在50℃下旋转蒸发浓缩。结果表明:当反应温度65℃(4#)时,所制得的磺酸化改性可德胶具有较好的溶解性。%In order to improve the water-soluble properties of curdlan, the curdlan modified by sulfonated was prepared. In this experiment, under the protection of nitrogen, curdlan was dissolved in dimethyl sulfoxide, then 0.5 g sulfur trioxide-pyridine was added to curdlan with continuous stirring for another 2 h, finally neutralized with 0.5 mol/L NaOH. Then deionized water was used to do dialysis, finally at 50 ℃, curdlan modified by sulphonic acid was obtained by rotary evaporation. When at 65℃(4 #), curdlan modified by sulfonated acid had much better solubility.

  10. Microstructure and Properties of Al2O3 Matrix Ceramic Coating Prepared by Thermo Chemical Reaction%热化学反应法制备Al2O3基陶瓷涂层的组织与性能

    Institute of Scientific and Technical Information of China (English)

    张媛; 周小飞

    2016-01-01

    The protective Al2O3 matrix ceramic coatings on the surface of 1Cr18Ni9 steel are prepared by thermo chemical reaction.The micro morphology,composition and structure of the combination layers were studied using SEM and EDS microanalysis instrument,and the corrosion resistance of the coating was tested by immersion corrosion experiments.The results show that the coating is dense and uniform,and there are chemical reaction between the ceramic coating and the matrix.And the existence of ceramic coating can effectively improve the corrosion resistance of 1Cr18Ni9 steel in acid and alkali.%采用热化学法在1Cr 18Ni9钢表面制备Al2O3基陶瓷涂层,利用SEM、EDS等微观分析仪器研究了结合层的微观形貌、成分及组织结构,利用浸泡腐蚀实验检测了涂层的耐蚀性.结果表明,涂层致密均匀,与基体发生了化学反应,陶瓷涂层的存在有效的提高了1Cr18Ni9钢的抗酸、碱腐蚀能力.

  11. 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%.

  12. 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)

  13. Viability of Listeria monocytogenes on Boneless, Water-Added Hams, Commercially Prepared with and without Food-Grade Chemicals, during Extended Storage at 4 and/or -2.2°C.

    Science.gov (United States)

    Luchansky, John B; Campano, Stephen G; Shoyer, Bradley A; Porto-Fett, Anna C S

    2016-04-01

    Viability of Listeria monocytogenes was monitored during refrigerated (4°C) and/or frozen (i.e., deep chilling at -2.2°C) storage on casing-cooked hams that were commercially prepared with and without potassium lactate and sodium diacetate (1.6%), buffered vinegar (2.2%), buffered vinegar and potassium lactate (1.7%), or a blend of potassium lactate, potassium acetate, and sodium diacetate (1.7%). A portion of these hams were subsequently surface treated with lauric arginate ester (LAE; 44 ppm). In phase I, hams (ca. 3.5 kg each) were sliced (ca. 0.7 cm thick, ca. 100 g), inoculated (ca. 4.0 log CFU per slice), surface treated with LAE, and stored at either 4°C for 120 days or at -2.2°C for 90 days and then at 4°C for an additional 120 days. In phase I, without antimicrobials, the population of L. monocytogenes increased by ca. 5.9 log CFU per slice within 120 days at 4°C; however, pathogen levels increased only slightly (ca. 0.45 log CFU per slice) for hams formulated with potassium lactate and sodium diacetate and decreased by ca. 1.2 log CFU per slice when formulated with the other antimicrobials. For slices held at -2.2°C and then stored at 4°C, but not treated with LAE, L. monocytogenes increased by ca. 4.5 log CFU per slice for controls, whereas when formulated with antimicrobials, pathogen levels decreased by ca. 1.4 to 1.8 log CFU per slice. For product treated with LAE, L. monocytogenes increased by ca. 4.0 log CFU per slice for controls, whereas when formulated with antimicrobials, pathogen levels decreased by ca. 0.9 to 1.9 log CFU per slice. In phase II, whole hams (ca. 1.0 kg each) containing antimicrobials were inoculated (6.8 log CFU per ham) and then stored at -2.2°C for 6 months. Pathogen levels decreased by ca. 2.0 to 3.5 log CFU per ham (without LAE treatment) and by ca. 4.2 to 5.2 log CFU per ham (with application of LAE via Sprayed Lethality in Container) when product was held at -2.2°C. In general, deep chilling hams was listericidal

  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. High-performance self-assembled graphene hydrogels prepared by chemical reduction of graphene oxide%化学还原氧化石墨烯制备高性能石墨烯自组装水凝胶

    Institute of Scientific and Technical Information of China (English)

    盛凯旋; 徐宇曦; 李春; 石高全

    2011-01-01

    提出了一种以抗坏血酸钠为还原剂,通过化学还原氧化石墨烯制备高性能石墨烯自组装水凝胶的方法.用扫描电镜,流变及电导率测试,光电子能谱,X-射线晶体衍射和拉曼光谱等手段对该石墨烯水凝胶的结构与性能进行了表征.结果表明:化学还原氧化石墨烯对形成石墨烯水凝胶具有决定性作用.该石墨烯水凝胶具有优异的导电性(1 S·m-1),机械强度和电化学性能.在1 mol·L-1的硫酸电解质溶液中,通过1.2A·g-1恒电流允放电测试,石墨烯水凝胶电极的比电容高达240F·g-1.%Three-dimensional self-assembled graphene hydrogels (SGHs)have been fabricated by chemical reduction of graphene oxide (GO)with sodium ascorbate. The SGHs were characterized by scanning electron microscopy,rheological tests,electrical conductivity measurements,X-ray photoelectron spectroscopy,X-ray diffraction,and Raman spectroscopy. Results indicate that the reduction of GO promotes the assembly of graphene sheets. The SGHs are electrically conductive(1s·m-1)and mechanically strong and exhibit excellent electrochemical performance.In 1 mol·L-1 aqueous solution of H2SO4,the specific capacitance of SGHs was measured to be about 240F·g-1 at a discharge current density of 1.2·-1.

  16. Impact of the electrochemical porosity and chemical composition on the lithium ion exchange behavior of polypyrroles (ClO4-, TOS-, TFSI-) prepared electrochemically in propylene carbonate. comparative EQCM, EIS and CV studies.

    Science.gov (United States)

    Dziewoński, Paweł Marek; Grzeszczuk, Maria

    2010-06-03

    Conditions of electrodeposition, i.e. a potential window of the process, addition of water, the current density, and morphology of substrate electrodes (Pt, Pt/TiO(2), Au), were shown to influence strongly ion-exchange properties of polypyrrole (PPy) synthesized in propylene carbonate (PC), doped with ClO(4)(-) or p-toluenesulfonate (TOS(-)). "Electrochemical porosity" and redox activity of PPy films were compared to the characteristics of poly(3,4-ethylenedioxythiophene) (PEDOT). A molecular indicator of the PPy film structure packing was bis(trifluoromethylsulfonyl)imide anion (TFSI(-)). Ion-exchange properties of PPy were found to be almost independent of chemical composition of the polymer, described in the literature as PPy(I), PPy(II), PPy(III). Instead, micro- and nanoscopic morphology of the polymer film and a molecular level packing of the polymer chains as well as the counterion nature are of the foremost importance. The polymer film structure/properties are shown to change upon prolonged redox/ionic stimulations. Lithium exchange between PPy films and contacting phases (PC electrolyte, TiO(2)) proceeds in addition to the anion exchange, the latter being a dominant process under conditions of the reversible electrochemical p-doping of PPy, although diffusion coefficients of PC solvated lithium ions in PPy are higher than diffusion coefficients of perchlorate, p-toluenesulfonate or bis(trifluoromethylsulfonyl)imide anions. The highest flux of Li(+) ions into/out of the PPy phase takes place about -1.0 V vs Ag/Ag(+) which is clearly evidenced by the cathodic/anodic CV peaks. Cation transport phenomena can be analyzed independently from anion transport when observed at a longer time scale (low values of potential scan rate) as each prevails at different redox states of the polymer. However, in a shorter time scale (v > or = 10 mV s(-1)), the opposite fluxes of cations and anions were observed to interfere. Furthermore, a net uptake of propylene carbonate by

  17. 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

  18. 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

  19. 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.

  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. 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.

  2. 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...

  3. 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…

  4. The Preparation and Characterization of Materials.

    Science.gov (United States)

    Wold, Aaron

    1980-01-01

    Presents several examples illustrating different aspects of materials problems, including problems associated with solid-solid reactions, sintering and crystal growth, characterization of materials, preparation and characterization of stoichiometric ferrites and chromites, copper-sulfur systems, growth of single crystals by chemical vapor…

  5. Chemically deposited tin sulphide

    Energy Technology Data Exchange (ETDEWEB)

    Akkari, A., E-mail: anis.akkari@ies.univ-montp2.f [Laboratoire de Physique de la Matiere Condensee, Faculte des Sciences de Tunis El Manar, Tunisie 2092 (Tunisia); Institut d' Electronique du Sud, Unite Mixte de Recherche 5214 UM2-CNRS (ST2i), Universite Montpellier 2, Place Eugene Bataillon, CC 082, 34095 Montpellier Cedex 5 (France); Guasch, C. [Institut d' Electronique du Sud, Unite Mixte de Recherche 5214 UM2-CNRS (ST2i), Universite Montpellier 2, Place Eugene Bataillon, CC 082, 34095 Montpellier Cedex 5 (France); Kamoun-Turki, N. [Laboratoire de Physique de la Matiere Condensee, Faculte des Sciences de Tunis El Manar, Tunisie 2092 (Tunisia)

    2010-02-04

    SnS thin films were deposited on glass substrates after multi-deposition runs by chemical bath deposition from aqueous solution containing 30 ml triethanolamine (TEA) (C{sub 6}H{sub 15}NO{sub 3}) (50%), 10 ml thioacetamide (CH{sub 3}CSNH{sub 2}), 8 ml ammonia (NH{sub 3}) solution and 10 ml of Sn{sup 2+}(0.1 M). These films were characterised with X-ray diffraction (XRD), with scanning electron microscopy, and with spectrophotometric measurements. The obtained thin films exhibit the zinc blend structure, the crystallinity seems to be improved as the film thickness increases and the band gap energy is found to be about 1.76 eV for film prepared after six depositions runs.

  6. Detection of Illegally Added Chemicals in Antihypertensive Traditional Chinese Medicine Preparations and Health Products by UPLC-MS/MS%UPLC-MS/MS法检测降压类中药制剂及保健品中添加的化学药品

    Institute of Scientific and Technical Information of China (English)

    田兰; 张继春; 陈睿; 储忠英; 包综方

    2013-01-01

    Objective: To establish a specific method for the determination of seven chemicals in antihypertensive traditional Chinese medicine preparations and health products. Method: Nifedipine, atenolol, prazosin hydrochloride, reserpine, clonidine hydro-chloride, captopril and hydrochlorothiazide were determined and analyzed by UPLC-MS/MS. An ACQUITY BEH C18 analysis column (2.1 mm×50 mm ,1.7 μm ) was used with the mobile phase of 0. 1 % formic acid and methanol with gradient elution. The flow rate was 0. 3 ml·min-1 . EIS ion source was used with positive and negative ion monitoring. Result: The standard curves of the seven chemicals showed good linearity over the concentration range of 62.5-2 000.0,65.6-2 100.0, 16.6-530.0,34.5-2 210.0,67.1-2 146.0,33.7-2 159.0, 1 637.3-104 790.0 ng·ml-1 , respectively. The average recoveries of the seven chemicals were within 85. 1% and 106.7% . Conclusion: The method is specific, sensitive,simple and quick,and can be used to detect the seven chemicals in antihypertensive traditional Chinese medicine preparations and health products.%目的:建立降压类中药制剂及保健品中非法添加7种化学药品的检测方法.方法:采用超高效液相色谱-串联四级杆质谱,多反应监测(MRM)模式进行定性和定量检测.采用ACQUITY BEH C18色谱柱(2.1 mm×50 mm,1.7 μm),流动相为0.1%甲酸-甲醇梯度洗脱,流速为0.3 ml·min-1;离子源为ESI源,正负离子检测,对中成药及保健品中添加硝苯地平、阿替洛尔、盐酸哌唑嗪、利血平、盐酸可乐定、卡托普利、氢氯噻嗪进行定性、定量检测.结果:7种化学药品测定的线性范围分别为62.5~2 000.0,65.6~2 100.0,16.6~530.0,34.5~2 210.0,67.1~2 146.0,33.7~2 159.0,1 637.3~104 790.0 ng·ml-1,7种化学药品平均回收率在85.1%~106.7%之间.结论:本方法选择性强、灵敏度高、处理方法简单,测定快速,可用于降压类中成药及保健品中添加7种化学药品的测定.

  7. 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 greywater after two days of storage with reductions of 62% and 55%, respectively. A significant (p greywater after seven days of storage.

  8. Thesis Preparation Manual

    OpenAIRE

    1999-01-01

    "This Thesis Preparation Manual has been written to provide you with format and procedure guidance for preparing and processing your thesis at the Naval Postgraduate School. It covers both unclassified and classified theses. All theses and thesis technical reports must be prepared in accordance with these guidelines. Please note that this manual is not written in the thesis format." form the Foreword

  9. CHEMICAL EVOLUTION

    Energy Technology Data Exchange (ETDEWEB)

    Calvin, Melvin

    1965-06-01

    How did life come to be on the surface of the earth? Darwin himself recognized that his basic idea of evolution by variation and natural selection must be a continuous process extending backward in time through that period in which the first living things arose and into the period of 'Chemical Evolution' which preceded it. We are approaching the examination of these events by two routes. One is to seek for evidence in the ancient rocks of the earth which were laid down prior to that time in which organisms capable of leaving their skeletons in the rocks to be fossilized were in existence. This period is sometime prior to approximately 600 million years ago. The earth is believed to have taken its present form approximately 4700 million years ago. We have found in rocks whose age is about 1000 million years certain organic molecules which are closely related to the green pigment of plants, chlorophyll. This seems to establish that green plants were already fluorishing prior to that time. We have now found in rocks of still greater age, namely, 2500 million years, the same kinds of molecules mentioned above which can be attributed to the presence of living organisms. If these molecules are as old as the rocks, we have thus shortened the time available for the generation of the complex biosynthetic sequences which give rise to these specific hydrocarbons (polyisoprenoids) to less than 2000 million years.

  10. Medical preparation container comprising microwave powered sensor assembly

    DEFF Research Database (Denmark)

    2016-01-01

    The present invention relates to a medical preparation container which comprises a microwave powered sensor assembly. The microwave powered sensor assembly comprises a sensor configured to measure a physical property or chemical property of a medical preparation during its heating in a microwave...

  11. 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.

  12. Chemical face peels.

    Science.gov (United States)

    Matarasso, S L; Glogau, R G

    1991-01-01

    Application of caustic chemicals to improve cosmesis and reverse actinic damage has been used for centuries. Although still not an exact science, it was not until the latter part of this century that peeling became more systematized. The indications, patient selection, armamentarium, histology, comprehension of the mechanisms of action, and safety parameters of peels have only recently become more extensively defined. Phenol, when used in the Baker's formula, provides the most dramatic results but also holds the most potential for systemic complications. Ideally suited for fair-skinned women, a phenol peel can provide substantial improvement in rhytidosis and actinic damage. Although the results of medium-depth peels approach those of Baker's peels, they are not quite as profound. Use of TCA and the medium-depth peels has filled an important gap between deep and superficial peels, however. Also ideal for light complexions, this category of peels lightens pigmentary problems and improves rhytides with minimal potential for systemic toxicity; however, local complications, including scarring and pigmentary anomalies, should not be underestimated. [table: see text] Superficial peels do not effectively eradicate the ravages of time and sun, but when done repetitively, they do improve pigmentary irregularities and may improve some minor surface changes and thus impart a fresher appearance to facial skin. Although pigmentary changes can occur, superficial peels are relatively safe, and maximal results can be achieved with serial applications. Peels have been categorized by patient indications and the corresponding depth of peeling required for improvement (Table 4). The depth is determined in turn by a host of factors (Table 5). Neither the classification scheme nor the peel process should be viewed dogmatically. Patients will often benefit from the concurrent use of different skin preparations and wounding agents. Localized gradations can be achieved not only with

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. Nature's chemicals and synthetic chemicals: comparative toxicology.

    OpenAIRE

    Ames, B N; Profet, M; Gold, L S

    1990-01-01

    The toxicology of synthetic chemicals is compared to that of natural chemicals, which represent the vast bulk of the chemicals to which humans are exposed. It is argued that animals have a broad array of inducible general defenses to combat the changing array of toxic chemicals in plant food (nature's pesticides) and that these defenses are effective against both natural and synthetic toxins. Synthetic toxins such as dioxin are compared to natural chemicals, such as indole carbinol (in brocco...

  18. 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.

  19. Chemical characterization of a marine conditioning film

    Digital Repository Service at National Institute of Oceanography (India)

    Garg, A.; Jain, A.; Bhosle, N.B.

    . 2. Materials and Methods 2.1. Chemicals and reagents Glass cover slips were purchased from Blue Star, India. Standard sugars and, myo- inositol were obtained from Sigma (St. Louis, MO, USA). Sodium carbonate, NaOH, HCl and methanol were of high... purity AR grades and were purchased from s.d. Fine Chemicals, Mumbai. Methanol was double distilled before use. Distilled water was purified using UV- Milli-Q water purification system (Millipore, Bangalore, India). 2.2. Preparation and deployment...

  20. Preparation of Li2TiO3 Tritium-breeding Ceramic Pebbles by an Optimized Wet Chemical Method%湿化学法制备Li2TiO3氚增殖陶瓷微球的最优工艺

    Institute of Scientific and Technical Information of China (English)

    孙敬锋; 王海燕; 王林祥; 李根兴

    2011-01-01

    With citric acid as binder, Li2TiO3 pebbles with diameter of 1. 20 mm and relative density about 91%TD were prepared by an optimized wet chemical method. Thermodynamical analysis, phase analysis and morphology observation were made on the product. The results showed that the sphericity of the Li2TiO3 pebbles was significantly affected by the amount of citric acid. The microstructure of the Ii2TiO3 pebbles was uniform and temperature-sensitive. The average grain size of the pebbles is below 3 μm after sintering at 1 050 ℃ for 6 h.%以柠檬酸为粘结剂,采用湿化学法成功制备了直径为1.20mm、相对密度为91%TD的Li2TiO3陶瓷微球,并系统地进行了热力学分析、物相分析和形貌观察.结果表明,粘结剂含量显著影响微球的球形度;所制备的Li2TiO3陶瓷微球具有均匀并且温度敏感的微观结构,在1 050℃下烧结6h后,平均晶粒尺寸小于3μm.

  1. 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

  2. Ultrafine Microstructure Composites Prepared by Chemical Vapor Deposition

    Science.gov (United States)

    1989-12-01

    pressed AIN from Denka , hot pressed BN+AlN from Union Carbide (71%BN, 20%AIN, and 4%B203 ) ..... . 217 5-57 XRD patterns of BN+AlN deposited on A1203 at...side wall of the top section of the graphite extension tube as shown in Figure 3-9. The top end of the extension tube was sealed using graphite cement ...samples) are shown in Figures 5-34 through 5-36. Also, the XRD spectra of uncoated A 20,O and hot-pressed AlN ( Denka , Inc.) are included in Figure 5-34 for

  3. 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.

  4. 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%.

  5. [Aesthetic surgery, psychic preparation].

    Science.gov (United States)

    Feiss, R

    2003-10-01

    The aesthetic surgery impacts the psychological picture of the body. The candidate must be prepared to this change in appearance. If not, the surgeon must suggest the psychological preparation, evaluating the risk of dissatisfaction, in order to allow the surgical and narcissistic success of his operation. The author, a psychiatric, beneficiary in a strong experience of a surgical assistance, develops the interest of such a preparation upon a period of about 15 years (1988-2002).

  6. 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,...

  7. 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.

  8. 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…

  9. 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.

  10. [Chemical constituents of Physalis pubescens].

    Science.gov (United States)

    Luo, Li-ping; Cheng, Fan-qin; Ji, Long; Yu, He-yong

    2015-11-01

    Chemical constituents of 95% ethanol extract of the dried persistent calyx of Physalis pubescens were investigated. By chromatography on a silica gel column and reverse-phase preparative HPLC, 10 compounds were isolated from the dichloromethane fraction. Based on the MS and 1D/2D NMR data, these compounds were identified as 5-O-(E-feruloyl) blumenol (1), isovanillin (2), (E) -ethyl 3-(4-hydroxyphenyl) acrylate (3), 4-hydroxybenzaldehyde(4), 4-methylphenol (5), (E) -methyl cinnamate (6), 7,3',4' trimethoxyquercetin (7), 5,3', 5'-trihydroxy-3,7,4'-trimethoxyflavone(8), danielone (9), and 5,5'-diisobutoxy-2,2'-bifuran (10).

  11. PNA-encoded chemical libraries.

    Science.gov (United States)

    Zambaldo, Claudio; Barluenga, Sofia; Winssinger, Nicolas

    2015-06-01

    Peptide nucleic acid (PNA)-encoded chemical libraries along with DNA-encoded libraries have provided a powerful new paradigm for library synthesis and ligand discovery. PNA-encoding stands out for its compatibility with standard solid phase synthesis and the technology has been used to prepare libraries of peptides, heterocycles and glycoconjugates. Different screening formats have now been reported including selection-based and microarray-based methods that have yielded specific ligands against diverse target classes including membrane receptors, lectins and challenging targets such as Hsp70.

  12. 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.

  13. 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...

  14. 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%.

  15. 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.

  16. Chemical ligation methods for the tagging of DNA-encoded chemical libraries.

    Science.gov (United States)

    Keefe, Anthony D; Clark, Matthew A; Hupp, Christopher D; Litovchick, Alexander; Zhang, Ying

    2015-06-01

    The generation of DNA-encoded chemical libraries requires the unimolecular association of multiple encoding oligonucleotides with encoded chemical entities during combinatorial synthesis processes. This has traditionally been achieved using enzymatic ligation. We discuss a range of chemical ligation methods that provide alternatives to enzymatic ligation. These chemical ligation methods include the generation of modified internucleotide linkages that support polymerase translocation and other modified linkages that while not supporting the translocation of polymerases can also be used to generate individual cDNA molecules containing encoded chemical information specifying individual library members. We also describe which of these approaches have been successfully utilized for the preparation of DNA-encoded chemical libraries and those that were subsequently used for the discovery of inhibitors.

  17. 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......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...... skills. Such skills are important in Chemical Product Engineering when dealing with open-ended problems, creative problem solutions, operating in a team working environment and exercising project management. In our course we emphasise team activites, formative feed back to the students as well as helping...

  18. Methylene Diphosphonate Chemical and Biological control of MDP complex

    CERN Document Server

    Aungurarat, A

    2000-01-01

    Technetium-9 sup 9 sup m MDP easy prepared from MDP kits which different sources such as OAP (In house), SIGMA. The resulting Tc 9 sup 9 sup m -MDP preparations were controlled in chemical and biological tests to compare the different results in these cases: radiochemical purity, the quantity of starting material and biodistribution result.

  19. 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...

  20. Nanostructured antireflective bilayers: Optical design and preparation

    Energy Technology Data Exchange (ETDEWEB)

    Detrich, Ádám [Budapest University of Technology and Economics, Department of Physical Chemistry and Materials Science, Centre for Colloid Chemistry, H-1521 Budapest (Hungary); Nagy, Norbert [Research Centre for Natural Sciences (MTA TTK), Institute for Technical Physics and Materials Science (MFA), P.O. Box 49, H-1525 Budapest (Hungary); Nyári, Mária; Albert, Emőke; Zámbó, Dániel [Budapest University of Technology and Economics, Department of Physical Chemistry and Materials Science, Centre for Colloid Chemistry, H-1521 Budapest (Hungary); Hórvölgyi, Zoltán, E-mail: zhorvolgyi@mail.bme.hu [Budapest University of Technology and Economics, Department of Physical Chemistry and Materials Science, Centre for Colloid Chemistry, H-1521 Budapest (Hungary)

    2014-05-01

    We show different methods for tailoring and fabrication of various cost-effective antireflective nanocoatings on transparent and non-transparent substrates. The main purpose was to prepare coatings with decreased reflectance in the full visible wavelength range using simple wet layer deposition techniques. Structure of coatings was designed by optical simulations applying simplified calculations. The refractive index of substrates was also considered for the calculations. The advantageous optical properties were achieved by bilayered structures combining compact and porous sol–gel derived oxide layers and nanoparticulate films. The bilayered structures enhance the flexibility of design by not only the selection of the layer thicknesses but also by different ways of adjusting the effective refractive index of the layers. Furthermore, chemical stability of the coatings was also investigated. The optical and structural properties of prepared films and bilayered coatings were studied by UV–vis spectroscopy and scanning electron microscopy, respectively. The transmittance of coated glass substrates was above 97.5%, while the reflectance of coated silicon substrates was below 4% between 450 nm and 900 nm. - Highlights: • Designed antireflective bilayered coatings on glass and silicon. • Simple, colloid chemical approaches to preparation. • Favorable optical properties by combining compact and porous oxide layers. • Different ways for adjusting the effective refractive index. • Strong chemical resistance against acidic effects.