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Sample records for preparing finely porous

  1. Preparation and characteristics of porous ceramics

    Institute of Scientific and Technical Information of China (English)

    Dongmei SHAO; Peiping ZHANG; Liyan MA; Juanjuan LIU

    2007-01-01

    Pyrophyllite is always used for making porous ceramics. In order to design the preparation technics of porous ceramics with pyrophyllite reasonably we must know the classifications, characteristics, properties and applications of porous ceramics. The classification and characteristics of porous ceramics are reviewed in this article; and several common preparations with their advantages and disadvantages are also introduced. The authors discussed the problems existing in researching and developing process for porous ceramics, and forecasted the development prospect of porous ceramics.

  2. Functional Ag porous films prepared by electrospinning

    Science.gov (United States)

    Dong, Guoping; Xiao, Xiudi; Liu, Xiaofeng; Qian, Bin; Liao, Yang; Wang, Chen; Chen, Danping; Qiu, Jianrong

    2009-06-01

    Face-centered cubic Ag porous films have been prepared directly from the heat treatment of AgNO 3-doped poly(vinyl alcohol) (PVA) electrospun nanofibers. Using Rhodamine B (RB) as the probing molecule, the surface-enhanced Raman scattering (SERS) effect of Ag porous films was demonstrated. The antibacterial activity of Ag porous films was also studied in this work. The propagation and biological activity of yeast cells were effectively inhibited by Ag porous films. These functional Ag porous films were expected to be applied in many fields, such as catalysis, diagnostics, sensors and antibacterial, etc.

  3. Method of preparing a porous silicon carbide

    NARCIS (Netherlands)

    Moene, R.; Tazelaar, F.W.; Makkee, M.; Moulijn, J.A.

    1994-01-01

    Abstract of NL 9300816 (A) Described is a method of preparing a porous silicon carbide suitable for use as a catalyst or as a catalyst support. Porous carbon is provided with a catalyst which is suitable for catalysing gasification of carbon with hydrogen, and with a catalyst suitable for cataly

  4. Method of preparing a porous silicon carbide

    NARCIS (Netherlands)

    Moene, R.; Tazelaar, F.W.; Makkee, M.; Moulijn, J.A.

    1994-01-01

    Abstract of NL 9300816 (A) Described is a method of preparing a porous silicon carbide suitable for use as a catalyst or as a catalyst support. Porous carbon is provided with a catalyst which is suitable for catalysing gasification of carbon with hydrogen, and with a catalyst suitable for cataly

  5. Method of preparing a porous silicon carbide

    NARCIS (Netherlands)

    Moene, R.; Tazelaar, F.W.; Makkee, M.; Moulijn, J.A.

    1994-01-01

    Abstract of NL 9300816 (A) Described is a method of preparing a porous silicon carbide suitable for use as a catalyst or as a catalyst support. Porous carbon is provided with a catalyst which is suitable for catalysing gasification of carbon with hydrogen, and with a catalyst suitable for

  6. Techniques for the Preparation of Porous Metals

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Porous metals have been developed greatly and swiftly in recent years. In this paper, main types of these materials are described briefly, and their preparation methods are related primarily, with the purpose offering some clues for optimizing the producing technology.

  7. Preparation and characterization of porous magnesium materials

    Institute of Scientific and Technical Information of China (English)

    LIU Xi-qin; LIU Zi-li; ZHANG Xiao-hong; FENG Jun-dong; YU Ta-xi

    2006-01-01

    The proper spacer material and the preparation technology for biological compatible porous magnesium materials were explored by the powder metallurgy method, and microstructures, porosity and mechanical properties of sintered porous magnesium were investigated. The results show that compared with spacer materials of NH4CO3, NH3Cl and carbamide, NH4CO3 is the best one for preparation of sintered porous magnesium, and the worst one is NH3Cl. The isolated blind pores are formed mainly by the particle interval of the magnesium powders. Adding spacer material favors the formation of open pores, while has little contribution to the formation of blind pores. The overall porosity and porosity of open pore of the sintered porous magnesium increase with the increase of added spacer material, while decrease with the increase of the molding stress. The mechanical properties of sintered porous magnesium increase with decreasing addition of spacer material and increasing molding stress.

  8. Method to prepare nanoparticles on porous mediums

    Science.gov (United States)

    Vieth, Gabriel M [Knoxville, TN; Dudney, Nancy J [Oak Ridge, TN; Dai, Sheng [Knoxville, TN

    2010-08-10

    A method to prepare porous medium decorated with nanoparticles involves contacting a suspension of nanoparticles in an ionic liquid with a porous medium such that the particles diffuse into the pores of the medium followed by heating the resulting composition to a temperature equal to or greater than the thermal decomposition temperature of the ionic liquid resulting in the removal of the liquid portion of the suspension. The nanoparticles can be a metal, an alloy, or a metal compound. The resulting compositions can be used as catalysts, sensors, or separators.

  9. Effects of Preparation on Luminescent Characterization of Porous Silicon

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Porous silicon samples are prepared by pulse electrochemical-etching and DC electrochemical-etching. The effects of different preparation methods on luminescent characterization of porous silicon are investigated. Compared with DC electrochemical-etching, pulse electrochemical-etching produces the porous silicon characterized by a more even surface, a stronger luminescence and a PL blue shift to a certain degree.

  10. Preparation of Porous Calcium Phosphate Bioceramic

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Porous calcium phosphate ceramics were prepared by slip casting and molding method respectively. By these two different methods, different microstructures can be got. By slip casting method, the pore size was 100- 350μm and 20- 80μm; pores were opened, interconnected and ball-like; the grain size was 2- 4 μm.By molding method, the pore size was 100-500 μm and 1-10μm; the grain size was 2-8μm. By slip casting method regular and interconnected pores can be got. By molding method the porosity and strength can be adjusted easily.

  11. Electrocatalysts using porous polymers and method of preparation

    Science.gov (United States)

    Liu, Di-Jia; Yuan, Shengwen; Goenaga, Gabriel A.

    2016-08-02

    A method of producing an electrocatalyst article using porous polymers. The method creates a porous polymer designed to receive transition metal groups disposed at ligation sites and activating the transition metals to form an electrocatalyst which can be used in a fuel cell. Electrocatalysts prepared by this method are also provided. A fuel cell which includes the electrocatalyst is also provided.

  12. Preparation and properties of biomedical porous titanium alloys by gelcasting.

    Science.gov (United States)

    Yang, Donghua; Shao, Huiping; Guo, Zhimeng; Lin, Tao; Fan, Lianpeng

    2011-08-01

    Porous titanium alloys have been prepared by gelcasting in this study. The elastic solid green body was first polymerized and then vacuum sintered to porous titanium alloys with low contamination by controlling sintering conditions. The microstructure and the total porosity of the vacuum sintered porous Ti-Co and Ti-Mo alloys were analyzed by using scanning electron microscopy and x-ray diffraction. Moreover, compression and bending tests were conducted to investigate their mechanical properties. The results show that open and closed three-dimensional pore morphologies and total porosity ranging from 38.34% to 58.32% can be achieved. In contrast to porous Ti by gelcasting, the compression and bending strengths of porous titanium alloys were significantly increased by adding Mo and Co with Young's modulus ranging between 7-25 GPa, which is close to that of human cortical bone, therefore being suited for potential application in load-bearing implants.

  13. Influence of preparation method on hydroxyapatite porous scaffolds

    Indian Academy of Sciences (India)

    N Monmaturapoj; C Yatongchai

    2011-12-01

    Hydroxyapatite (HA) is extensively used in medical applications as an artificial bone because of its similarity to the natural components of human bones and for its excellent biocompatibility. The porous structure of HA ceramics is more generally used as a scaffold. Many techniques, which are performed under fluid system, have been applied to fabricate HA porous scaffolds. In this work, polymeric sponge technique was employed in the preparation of HA slurry appropriated for porous ceramic fabrication. Effort for strength improvement was made on porous HA ceramic in several aspects. The effect of HA/water, binder/plasticizer ratios and dispersant content on the rheological properties of HA suspension in combination with the addition of SiC and SiO2 on the compressive strength of porous bodies were investigated and discussed.

  14. Preparation of Porous Mullite Composite by Microwave Sintering

    Institute of Scientific and Technical Information of China (English)

    FAN Bingbing; ZHANG Rui; SUN Bing; LI Xuqin; LI Chunguang

    2012-01-01

    Microwave sintering method was carried out to prepare porous mullite composite.An insulation structure based on hybrid heating mode was well designed with the wall of mullite and the aided heaters of SiC.The obtained samples were characterized by XRD analysis,apparent porosity detection,and bending strength measurement.SEM was used to observe the microstructure of the sample.It is found that the porous mullite composite could be prepared through the microwave sintering within 2 h at relatively low temperatures around 1000 ℃.The lasted samples show comparatively superior properties to the products prepared by conventional processing.

  15. Porous Materials from Thermally Activated Kaolinite: Preparation, Characterization and Application

    Directory of Open Access Journals (Sweden)

    Jun Luo

    2017-06-01

    Full Text Available In the present study, porous alumina/silica materials were prepared by selective leaching of silicon/aluminum constituents from thermal-activated kaolinite in inorganic acid or alkali liquor. The correlations between the characteristics of the prepared porous materials and the dissolution properties of activated kaolinite were also investigated. The results show that the specific surface area (SSA of porous alumina/silica increases with silica/alumina dissolution, but without marked change of the BJH pore size. Furthermore, change in pore volume is more dependent on activation temperature. The porous alumina and silica obtained from alkali leaching of kaolinite activated at 1150 °C for 15 min and acid leaching of kaolinite activated at 850 °C for 15 min are mesoporous, with SSAs, BJH pore sizes and pore volumes of 55.8 m2/g and 280.3 m2/g, 6.06 nm and 3.06 nm, 0.1455 mL/g and 0.1945 mL/g, respectively. According to the adsorption tests, porous alumina has superior adsorption capacities for Cu2+, Pb2+ and Cd2+ compared with porous silica and activated carbon. The maximum capacities of porous alumina for Cu2+, Pb2+ and Cd2+ are 134 mg/g, 183 mg/g and 195 mg/g, respectively, at 30 °C.

  16. The effect of the presence of fine YSZ particles on the performance of porous nickel electrodes

    NARCIS (Netherlands)

    Boer, de B.; Gonzalez, M.; Bouwmeester, H.J.M.; Verweij, H.

    2000-01-01

    The electrochemical performance of a porous nickel electrode with its surface modified by deposition with fine yttria-stabilised zirconia (YSZ) powder is compared with that of the ‘bare’ electrode. Image analysis of the electrode microstructure yields values for the triple phase boundary (TPB) lengt

  17. Preparation of 3-D porous fibroin scaffolds by freeze drying with treatment of methanol solutions

    Institute of Scientific and Technical Information of China (English)

    ZHAN JingLin; SUN XiaoDan; CUI FuZhai; KONG XiangDong

    2007-01-01

    In this study,silk scaffolds with appropriate porous structures were prepared by adjusting solution concentrations and providing treatment with methanol solutions in the way of freeze drying. The effects of the preparation conditions on the microstructures and properties of the scaffolds were discussed. Fibroin solutions with different concentrations of 4,6,8,10 wt% were used respectively to prepare the scaffolds. The effects of the addition of 20 vol% methanol before or after freeze drying to the 4 wt% fibroin solution were investigated. As demonstrated by Scanning Electron Microscope (SEM),the fibroin scaffolds prepared without methanol had porous microstructures composed of thin sheets,and the sizes of the pores decreased with the increase of the fibroin solution concentrations,while the scaffolds prepared in the presence of methanol showed porous microstructures formed by fine-particle aggregates. The porosities and mechanical properties of the prepared fibroin scaffolds under different conditions were tested. The crystalline structures and conformations of the fibroin scaffolds were detected by Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD).

  18. Fabrication and thermo-mechanical behavior of ultra-fine porous copper.

    Science.gov (United States)

    Kreuzeder, Marius; Abad, Manuel-David; Primorac, Mladen-Mateo; Hosemann, Peter; Maier, Verena; Kiener, Daniel

    2015-01-01

    Porous materials with ligament sizes in the submicrometer to nanometer regime have a high potential for future applications such as catalysts, actuators, or radiation tolerant materials, which require properties like high strength-to-weight ratio, high surface-to-volume ratio, or large interface density as for radiation tolerance. The objective of this work was to manufacture ultra-fine porous copper, to determine the thermo-mechanical properties, and to elucidate the deformation behavior at room as well as elevated temperatures via nanoindentation. The experimental approach for manufacturing the foam structures used high pressure torsion, subsequent heat treatments, and selective dissolution. Nanoindentation at different temperatures was successfully conducted on the ultra-fine porous copper, showing a room temperature hardness of 220 MPa. During high temperature experiments, oxidation of the copper occurred due to the high surface area. A model, taking into account the mechanical properties of the copper oxides formed during the test, to describe the measured mechanical properties in dependence on the proceeding oxidation was developed. The strain rate sensitivity of the copper foam at room temperature was ∼0.03 and strongly correlated with the strain rate sensitivity of ultra-fine grained bulk copper. Although oxidation occurred near the surface, the rate-controlling process was still the deformation of the underlying copper. An increase in the strain rate sensitivity was observed, comparably to that of ultra-fine-grained copper, which can be linked to thermally activated processes at grain boundaries. Important insights into the effects of oxidation on the deformation behavior were obtained by assessing the activation volume. Oxidation of the ultra-fine porous copper foam, thereby hindering dislocations to exit to the surface, resulted in a pronounced reduction of the apparent activation volume from ~800 to ~50 b(3), as also typical for ultra-fine grained

  19. Porous NiTi alloy prepared from combustion synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Li Yonghua; Rong Lijian; Li Yiyi [Chinese Academy of Sciences, Shenyang (China). Inst. of Metal Research

    2002-07-01

    Porous NiTi shape memory alloy (SMA) is a promising biomaterial which can be used as replacement of hard tissue implant. It was prepared from elemental titanium and nickel powders by method of combustion synthesis. The phase composition, pore and fracture morphology were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM) respectively. Meanwhile the compressive mechanical property was also studied. The preliminary data indicated that porous NiTi SMA prepared from combustion synthesis had homogeneous pore distribution and proper mean pore size. The mechanical property of pure product depended strongly on preheating temperature during synthesis process. It has also good superelasticity. (orig.)

  20. Preparation of biodegradable porous poly(butylene succinate microspheres

    Directory of Open Access Journals (Sweden)

    Pepić Dragana

    2008-01-01

    Full Text Available The aim of this study was to determine the optimal conditions for the fabrication of porous microspheres based on poly(butylene succinate, PBS. The biodegradable non-porous PBS microspheres were prepared by the oil-in-water (o/w emulsion solvent evaporation method using poly(vinyl alcohol, PVA, as the surfactant. Fabrication conditions, such as stirring rate, organic/aqueous ratio, PBS concentration and surfactant (PVA concentration, which have an important influence on both the particle size and the morphology of the microspheres, were varied. Scanning electron microscopy, SEM, observations confirmed the size, size distribution and surface morphology of the microspheres. The optimal conditions for the preparation of the non-porous microspheres were found to be: concentration the PBS solution, 10 mass%; PVA concentration, 1 mass%; the organic/ aqueous ratio CHCl3/H2O = 1/20 and stirring rate 800 rpm. Porous PBS microspheres were fabricated under the optimal conditions using various amounts of hexane and poly(ethylene oxide, PEO, as porogens. The influence of the amount of porogen on the pore size and the particle size was investigated using SEM and the apparent density. The microspheres exhibited various porosities and the pore sizes. The average particle size of the microspheres with PEO as the porogen was from 100 to 122μm and that of the microspheres with hexane as the porogen was from 87 to 97μm. The apparent density of the porous microspheres with PEO as the porogen, from 0.16 to 0.23 g/cm3, was much smaller than the non-porous microspheres, 0.40 g/cm3. In the in vitro degradation experiments, the porous microspheres were incubated in phosphate buffer solution (pH 7 at 37°C. After incubating for one month, the microspheres showed significant extent of the hydrolytic degradation of the porous PBS microspheres.

  1. Preparation of porous hydroxyapatite ceramics with starch additives

    Institute of Scientific and Technical Information of China (English)

    YANG Lei; NING Xiao-shan; CHEN Ke-xin; XIAO Qun-fang; ZHOU He-ping

    2005-01-01

    Porous ceramics prepared from nano-sized hydroxyapatite powders by adding water soluble starch and insoluble starch were investigated. The results show that small pores of several micrometers or less can be produced by adding water soluble starch as a pore former. Two kinds of starch have different pore forming mechanisms. The permeability of the porous ceramics can be greatly improved by adding the insoluble starch to channel the small pores rather than solely using water soluble starch. The control of permeability can be achieved by adjusting the content ratio of water soluble starch to insoluble starch. Strength tests show the ceramics have rather high strength. Therefore a kind of porous filtering material with small pores, controllable permeability and good strength can be prepared by using starch additives.

  2. Method for the preparation of ferrous low carbon porous material

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Curtis Jack

    2014-05-27

    A method for preparing a porous metal article using a powder metallurgy forming process is provided which eliminates the conventional steps associated with removing residual carbon. The method uses a feedstock that includes a ferrous metal powder and a polycarbonate binder. The polycarbonate binder can be removed by thermal decomposition after the metal article is formed without leaving a carbon residue.

  3. Method for the preparation of ferrous low carbon porous material

    Science.gov (United States)

    Miller, Curtis Jack

    2014-05-27

    A method for preparing a porous metal article using a powder metallurgy forming process is provided which eliminates the conventional steps associated with removing residual carbon. The method uses a feedstock that includes a ferrous metal powder and a polycarbonate binder. The polycarbonate binder can be removed by thermal decomposition after the metal article is formed without leaving a carbon residue.

  4. Preparation and Characterization of Porous Calcium Phosphate Bioceramics

    Institute of Scientific and Technical Information of China (English)

    Honglian Dai; Xinyu Wang; Yinchao Han; Xin Jiang; Shipu Li

    2011-01-01

    β-tricalcium phosphate (β-TCP) powder and Na2O-CaO-MgO-P2O5 glass binder were synthesized and mixed, and then the biodegradable porous calcium phosphate ceramics were successfully prepared by foaming and sintering at 850℃. The as-prepared ceramics possess a high porosity with partial three-dimension interconnected macro- and micro-pores. As in vitro experiment testified, the calcium phosphate ceramics (CPCs) has good degradability.

  5. Properties of porous magnesium prepared by powder metallurgy.

    Science.gov (United States)

    Čapek, Jaroslav; Vojtěch, Dalibor

    2013-01-01

    Porous magnesium-based materials are biodegradable and promising for use in orthopaedic applications, but their applications are hampered by their difficult fabrication. This work reports the preparation of porous magnesium materials by a powder metallurgy technique using ammonium bicarbonate as spacer particles. The porosity of the materials depended on the amount of ammonium bicarbonate and was found to have strong negative effects on flexural strength and corrosion behaviour. However, the flexural strength of materials with porosities of up to 28 vol.% was higher than the flexural strength of non-metallic biomaterials and comparable with that of natural bone.

  6. Preparation and elements analysis of porous fluorescent glasses

    Institute of Scientific and Technical Information of China (English)

    ZHU Dong-mei; LUO Fa; ZHOU Wan-cheng; D. E. DAY; C. S. RAY

    2006-01-01

    A large variety of porous fluorescent glasses were prepared and the concentration of different elements in these glasses was analyzed. The start porous glasses were soaked in a solution containing soluble salts and then heated at 650 ℃ for 3 h to decompose the salts in the pores into oxides. Fluorescent agents,such as UO3,Eu2O3,were impregnated into the porous glasses to prepare the fluorescent glasses. The results show that soaking is a feasible method to prepare the glass sphere with compositions distinguishable from each other and easy to be located in a complicated background. Six or more components can be impregnated together into one glass sample and the concentration of them can be analyzed accurately. UO3 and Eu2O3 can be impregnated into porous glass to make the glass strongly fluorescent. Higher concentration of Eu2O3 produces stronger fluorescence while higher concentration of UO3 reduces the fluorescence intensity because of the concentration quenching effect.

  7. Coupled fluid and solid mechanics study for improved permeability estimation of fines' invaded porous materials

    Science.gov (United States)

    Mirabolghasemi, M.; Prodanovic, M.

    2012-12-01

    The problem of fine particle infiltration is seen in fields from subsurface transport, to drug delivery to industrial slurry flows. Sediment filtration and pathogen retention are well-known subsurface engineering problems that have been extensively studied through different macroscopic, microscopic and experimental modeling techniques Due to heterogeneity, standard constitutive relationships and models yield poor predictions for flow (e.g. permeability) and rock properties (e.g. elastic moduli) of the invaded (damaged) porous media. This severely reduces our ability to, for instance, predict retention, pressure build-up, newly formed flow pathways or porous medium mechanical behavior. We chose a coupled computational fluid dynamics (CFD) - discrete element modeling (DEM) approach to simulate the particulate flow through porous media represented by sphere packings. In order to minimize the uncertainty involved in estimating the flow properties of porous media on Darcy scale and address the dynamic nature of filtration process, this microscopic approach is adapted as a robust method that can incorporate particle interaction physics as well as the heterogeneity of the porous medium.. The coupled simulation was done in open-source packages which has both CFD (openFOAM) and DEM components (LIGGGHTS). We ran several sensitivity analyses over different parameters such as particle/grain size ratio, fluid viscosity, flow rate and sphere packing porosity in order to investigate their effects on the depth of invasion and damaged porous medium permeability. The response of the system to the variation of different parameters is reflected through different clogging mechanism; for instance, bridging is the dominant mechanism of pore-throat clogging when larger particles penetrate into the packing, whereas, in case of fine particles which are much smaller than porous medium grains (1/20 in diameter), this mechanism is not very effective due to the frequent formation and

  8. Preparation of porous lanthanum phosphate with templates

    Energy Technology Data Exchange (ETDEWEB)

    Onoda, Hiroaki, E-mail: onoda@kpu.ac.jp [Department of Informatics and Environmental Sciences, Faculty of Life and Environmental Sciences, Kyoto Prefectural University, 1-5, Shimogamo Nakaragi-cyo, Sakyo-ku, Kyoto 606-8522 (Japan); Ishima, Yuya [Department of Applied Chemistry, Faculty of Life Sciences, Ritsumeikan University, 1-1-1, Nojihigashi, Kusatsu, Shiga 525-8577 (Japan); Takenaka, Atsushi [Department of Materials Science, Yonago National College of Technology, 4448, Hikona-cho, Yonago, Tottori 683-8502 (Japan); Tanaka, Isao [Department of Materials Science and Engineering, Faculty of Engineering, Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501 (Japan)

    2009-08-05

    Malonic acid, propionic acid, glycine, n-butylamine, and urea were added to the preparation of lanthanum phosphate from lanthanum nitrate and phosphoric acid solutions. All additives were taken into lanthanum phosphate particles. The additives that have a basic site were easy to contain in precipitates. The addition of templates improved the specific surface area of lanthanum phosphate. The amount of pore, with radius smaller than 4 nm, increased with the addition of templates. The remained additives had influence on the acidic properties of lanthanum phosphate.

  9. Preparation and antimicrobial ability of natural porous antibacterial materials

    Institute of Scientific and Technical Information of China (English)

    DONG Fa-qin; LI Guo-wu; SUN Zhi-gang; SHEN Gang; FENG Qi-ming; DAI Qun-wei

    2005-01-01

    The liquid ion exchange method, solid salt melt method and dry-wet circulation method were used to prepare natural porous antimicrobial materials with natural minerals, such as zeolite, spilite, palygorskite and montmorillonite, respectively. Atomic absorption spectrum and X-ray diffraction analysis were carried out to investigate the effects of Ag+, Cu2+ and Zn2+ on antimicrobial abilities of natural porous minerals, and the effect of preparation method on ion exchange capacity of antimicrobial material, respectively. The results show that for the ion exchange capacity, clay mineral is higher than fibrous mineral, i.e. both zeolite and montmorillonite are higher; the antimicrobial ability of material with Ag+ is the best; the exchange capacities of materials with Cu2+ or Zn2+ are all higher, but the antimicrobial ability of Cu2+ is better than that of Zn2+.

  10. Preparation, characterization and cytocompatibility of bioactive coatings on porous calcium-silicate-hydrate scaffolds

    Energy Technology Data Exchange (ETDEWEB)

    Mansur, Alexandra A.P. [Department of Metallurgical and Materials Engineering of Federal University of Minas Gerais, Rua Espirito Santo, 35/316, Centro, CEP: 30.160-030, Belo Horizonte (Madagascar) (Brazil); Mansur, Herman S., E-mail: hmansur@demet.ufmg.br [Department of Metallurgical and Materials Engineering of Federal University of Minas Gerais, Rua Espirito Santo, 35/316, Centro, CEP: 30.160-030, Belo Horizonte (Madagascar) (Brazil)

    2010-01-30

    The major goal of this research was to investigate and characterize the deposition of a biomimetic apatite-like coating onto the surface of 3D porous calcium-silicate-hydrate scaffolds with suitable bioactivity for potential application in bone tissue engineering. Basically, Portland cement, water, sand and lime were mixed for preparing the slurry which was poured into molds, and fine aluminum powder was added as foaming agent resulting on the formation of porous 3D structures. After aging for 28 days, these porous inorganic scaffolds were immersed in calcium chloride supersaturated solution in PBS for 7 days at 37 deg. C for the biomimetic layer deposition. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier Transformed Infrared Spectroscopy (FTIR) techniques were used in order to characterize the porous scaffolds and the apatite-like biomimetic coating. The results have showed that 3D constructs were successfully produced with interconnected porosity, compressive strength and cytocompatibility appropriate for potential use as an alternative in trabecular bone repair.

  11. Process for preparing fine-grain metal carbide powder

    Science.gov (United States)

    Kennedy, C.R.; Jeffers, F.P.

    Fine-grain metal carbide powder suitable for use in the fabrication of heat resistant products is prepared by coating bituminous pitch on SiO/sub 2/ or Ta/sub 2/O/sub 5/ particles, heating the coated particles to convert the bituminous pitch to coke, and then heating the particles to a higher temperature to convert the particles to a carbide by reaction of said coke therewith.

  12. Preparation of Porous Silica Ceramics with Low Dielectric Constant

    Institute of Scientific and Technical Information of China (English)

    MAO Xiao-jian; WANG Shi-wei; SHIMAI Shun-zo

    2006-01-01

    Porous silica ceramics has been prepared with the starch consolidation casting method. Slurries with various fractions of starch added in were prepared by ball-milling. The evaluation of the microstructures was done through two techniques: Hg porosimetry and SEM investigation. The bending strength of the sintered samples varied within the range of 10 MPa-20 MPa and the low dielectric constant within the range of 2.0-2.4 correspondent with the porosity of 42%-56%. The ceramics holds a brilliant promise of being a kind of core material used in sandwich-like electromagnetic windows.

  13. Preparation of porous carbon particle with shell/core structure

    Directory of Open Access Journals (Sweden)

    2007-05-01

    Full Text Available Porous carbon particles with a shell/core structure have been prepared successfully by controlled precipitation of the polymer from droplets of oil-in-water emulsion, followed by curing and carbonization. The droplets of the oil phase are composed of phenolic resin (PFR, a good solvent (ethyl acetate and porogen (Poly(methyl methacrylate, PMMA. The microstructure was characterized in detail by scanning electron microscopy (SEM, transmission electron microscopy (TEM, nitrogen adsorption, and thermo gravimetric analysis (TGA. The obtained carbon particles have a capsular structure with a microporous carbon shell and a mesoporous carbon core. The BET surface area and porous volume are calculated to be 499 m2g-1 and 0.56 cm3g-1, respectively. The effects of the amount of porogen (PMMA, co-solvent (acetone and surfactant on the resultant structure were studied in detail.

  14. Preparation of porous silicon carbide by combustion synthesis

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yu-min; ZHANG Jian-han; HAN Jie-cai

    2005-01-01

    Porous silicon carbide ceramics were prepared by combustion synthesis technique. SiC/TiC composite was gained by combustion reaction of Si, C and Ti. Thermodynamics analysis of Si-C-Ti system indicates that the content of TiC in products should be larger than 30%. The experimental results show that the content of Ti+C should be larger than 25% to achieve a complete combustion reaction. The X-ray diffractometry results show that the final products with a relative density of 45%-64% are composed of α-SiC, β-SiC, TiC and a small quantity of Si. The images of scanning electron microscopy show that the structures of grain in SiC based porous ceramics consist of particles with a few microns in size.

  15. Preparation and Electrochemical Properties of Porous Platinum Electrode

    Institute of Scientific and Technical Information of China (English)

    HE Xin; CHEN Boxun; CHEN Qiao

    2012-01-01

    Porous platinum electrodes were prepared by adding YSZ,as an active material,in platinum paste.Relationship between microstructure and electrochemical performance of O2(g),Pt/YSZ electrode have been characterized by SEM and cyclic voltammetry.Results showed that the microstructure of platinum electrode is a significant impact on the cyclic voltammetry.With the increase of platinum electrode's porosity,the area of three-phase boundary of O2(g)/Pt/YSZ was increased.The electrochemical reactivity was also enhanced.These were presented as the increase of current density and cathode voltage in cyclic voltammetry.

  16. Preparation and characterization of porous Si3N4 ceramics prepared by compression molding and slip casting methods

    Indian Academy of Sciences (India)

    Yu Fangli; Wang Huanrui; Bai Yu; Yang Jianfeng

    2010-10-01

    Porous silicon nitride (Si3N4) ceramics were fabricated by compression molding and slip casting methods using petroleum coke as pore forming agent, and Y2O3–Al2O3 as sintering additives. Microstructure, mechanical properties and gas permeability of porous Si3N4 ceramics were investigated. The mechanical properties and microstructure of porous Si3N4 ceramics prepared by compression molding were better than those which were prepared by slip casting method, whereas slip casting method is suitable for the preparation of porous Si3N4 ceramics with higher porosity and excellent gas permeability.

  17. Preparation and properties of β-tricalcium phosphate porous bioceramic

    Institute of Scientific and Technical Information of China (English)

    张士华; 熊党生; 崔崇

    2004-01-01

    Porous β-tricalcium phosphate bioceramic (PTCP) has important roles in surgical implants because of good biocompatibility. But the low compressive strength of the ceramic limits its application. The preparation of PTCP was improved with the adjustment of the constituents and the sintering-process. A new type of PTCP material with high compressive strength was made. The compositions, microstructure and properties of PTCP were analyzed by TG-DSC, XRD, TEM, SEM and so on. The result indicates that stearic acid burns sufficiently and gives out carbon dioxide and water vapor when slowly heated between 200 ℃ and 400 ℃ so that the porous structure like coral in β-TCP bioceramic is formed. Through crystallization at 470 ℃ and 570 ℃, more CaO-P2O5 glass-cement is converted into crystallite-glass, which is beneficial for improving the compressive strength of β-TCP bioceramic.PTCP can form a support action in bone imperfect section with good solubility.

  18. Preparation of Hollow Porous HAP Microspheres as Drug Delivery Vehicles

    Institute of Scientific and Technical Information of China (English)

    WANG Qing; HUANG Wenhai; WANG Deping

    2007-01-01

    Hollow HAP microspheres in sub-millimeter size were prepared and investigated as a drug delivery vehicle. The LCB (lithium-calcium borate) glass microspheres, which were made through flame spray process, were chosen as precursor for hollow HAP microspheres. The LCB glass microspheres reacted with phosphate buffer (K2HPO4) solution for 5 days at 37 ℃. During the reaction the Ca-P-OH compound precipitated on the surface of LCB glass microspheres and formed porous shells. Then the microspheres turned to be hollow ones with the same diameter as the glass microspheres after LCB glass run out in the chemical reaction. After heat-treated at 600 ℃ for 4 h, the Ca-P-OH compound became HAP, thus the hollow HAP microspheres were produced. The mechanism of forming hollow HAP microspheres through the chemical reaction between phosphate buffer and LCB glass was confirmed by the XRD analysis. The microstructure characteristics of the hollow, porous microspheres were observed by SEM.

  19. Preparation and Characterization of Temperature-responsive Porous Monoliths

    Institute of Scientific and Technical Information of China (English)

    ZHANG, Rongyue; QI, Li; XIN, Peiyong; YANG, Gengliang; CHEN, Yi

    2009-01-01

    A new temperature-responsive porous monolith has been prepared by surface-initiated activators generated by electron transfer atom transfer radical polymerization (AGET ATRP) grafting poly(N-isopropylacrylamide) (PNIPAAm) within the pores of the porous polymer monolith. The grafting copolymerization was carried out by a method based on a continuous flow-through technique without special deoxygenation procedure needed in the general ATRP. The addition of ascorbic acid could counteract the oxidation effect of oxygen diffusing into the reaction system. The resulting grafted monolith was characterized by a mercury intrusion method and the size of macropore was 3.65 μm, which was suitable for flow through the monolith for HPLC. The thermally responsive property of the grafted monolith was evaluated by HPLC using steroids with various hydrophobicities as probes. Through determination of retention factor of each steroid on the grafted monolith at different temperatures using water as mobile phase, it was found that the slope of the plot of retention factor of each steroid versus the temperature changed around the low critical solution temperature (LCST, 32 ℃) of PNIPAAm in water. It was relative to the grafted PNIPAAm temperature sensitivity that a hydrophobic and hydrophilic alternation would take place around its LCST.Based on this thermally responsive property, the grafted monolith was used as stationary phase for HPLC and to separate the steroids using water as mobile phase by changing the column temperature. As a mobile phase, water is much better than organic solvents concerning the environment.

  20. Porous Si layers-Preparation, characterization and morphology

    Energy Technology Data Exchange (ETDEWEB)

    Badawy, Waheed A., E-mail: wbadawy@cu.edu.e [Chemistry Department, Faculty of Science, Cairo University, Gamaa Street, 12 613 Giza (Egypt); El-Sherif, Rabab M.; Khalil, Shaaban A. [Chemistry Department, Faculty of Science, Cairo University, Gamaa Street, 12 613 Giza (Egypt)

    2010-12-01

    Porous silicon layers (PSL) of nano- and micro-structures were prepared by metal-assisted electroless etching of silicon in HF-oxidizing agent aqueous solutions. The effect of oxidizing agent and HF content on the characteristics of the formed porous layers was investigated. A thin Pt film was electroless deposited on p-Si<1 0 0> prior to immersion in the etching solution. The properties and morphology of the PSL formed by this method were investigated by electrochemical impedance spectroscopy (EIS) scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) technique. The characteristics of the PSL were found to be affected by the constituents of the etching medium and also, the etching time. Potassium bromate (KBrO{sub 3}), potassium iodate (KIO{sub 3}), and potassium dichromate (K{sub 2}Cr{sub 2}O{sub 7}) have been used as oxidizing agents. Pt-assisted etching of p-Si for 1 h in an etching solution consisting of 22.0 M HF and 0.05 M of KBrO{sub 3}, results in the formation of nano- and micro-pores on the Si surface. The use of 0.05 M KIO{sub 3} or K{sub 2}Cr{sub 2}O{sub 7} as oxidizing agent has led to the formation of a deposit on the silicon surface. At relatively higher concentration [>0.05 M] of K{sub 2}Cr{sub 2}O{sub 7} the surface deposit becomes clear and was found to consist of an insoluble passive solid-phase of K{sub 2}SiF{sub 6} which increases the film impedance and blocks the porous structure formation. The use of higher concentration [>22 M] of HF in the etching electrolyte is accompanied by an increase in the dissolution rate of the insoluble K{sub 2}SiF{sub 6} layer and a decrease in the PSL passivity. The experimental impedance data were fitted to theoretical data according to a proposed equivalent circuit model which accounts for the mechanism of the porous film formation at the Si/electrolyte interface.

  1. Preparation and dielectric properties of porous silicon nitride ceramics

    Institute of Scientific and Technical Information of China (English)

    LI Jun-qi; LUO Fa; ZHU Dong-mei; ZHOU Wan-cheng

    2006-01-01

    Porous silicon nitride ceramics with difference volume fractions of porosity from 34.1% to 59.2% were produced by adding different amount of the pore-forming agent into initial silicon nitride powder. The microwave dielectric property of these ceramics at a frequency of 9.36 GHz was studied. The crystalline phases of the samples were determined by X-ray diffraction analysis. The influence of porosity on the dielectric properties was evaluated. The results show that α-Si3N4 crystalline phase exists in all the samples while the main crystalline phase of the samples is β-Si3N4,indicating that the a/b transformation happens during the preparation of samples and the transformation is incomplete. There is a dense matrix containing large pores and cavities with needle-shaped and flaky β-Si3N4 grains distributing. The dielectric constant of the ceramics reduces with the increase of porosity.

  2. Design, preparation, and application of ordered porous polymer materials

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Qingquan, E-mail: qqliu@hnust.edu.cn; Tang, Zhe; Ou, Baoli; Liu, Lihua; Zhou, Zhihua, E-mail: zhou7381@126.com; Shen, Shaohua; Duan, Yinxiang

    2014-04-01

    Ordered porous polymer (OPP) materials have extensively application prospects in the field of separation and purification, biomembrane, solid supports for sensors catalysts, scaffolds for tissue engineering, photonic band gap materials owing to ordered pore arrays, uniform and tunable pore size, high specific surface area, great adsorption capacity, and light weight. The present paper reviewed the preparation techniques of OPP materials like breath figures, hard template, and soft template. Finally, the applications of OPP materials in the field of separation, sensors, and biomedicine are introduced, respectively. - Highlights: • Breath figures involve polymer casting under moist ambience. • Hard template employs monodisperse colloidal spheres as a template. • Soft template utilizes the etched block in copolymers as template.

  3. Preparation and Photocatalytic Property of Porous TiO2 Film with Net-like Framework

    Institute of Scientific and Technical Information of China (English)

    XU Rong-guo; YAO Jian-xi; LAI Xiao-yong; MAO Dan; XING Chao-jian; WANG Dan

    2009-01-01

    By the UV-curing method, a porous TiO2 film with net-like framework has been prepared. The characte-rization results of the porous TiO2 film by means of SEM, TEM, XRD, and N2 adsorption-desorption analysis show that the net-like framework of the porous TiO2 film is composed of TiO2 nanoparticles, forming three dimensional porous structure. The porous TiO2 film exhibits higher photocatalytic activity for the degradation of methylene blue(MB) dye compared with the conventional dense TiO2 film.

  4. Enhanced photoconductivity and fine response tuning in nanostructured porous silicon microcavities

    Energy Technology Data Exchange (ETDEWEB)

    Urteaga, R; MarIn, O; Acquaroli, L N; Schmidt, J A; Koropecki, R R [INTEC-UNL-CONICET, Guemes 3450 - 3000 Santa Fe (Argentina); Comedi, D, E-mail: rkoro@intec.ceride.gov.a [CONICET y LAFISO, Departamento de Fisica, FACET, Universidad Nacional de Tucuman (Argentina)

    2009-05-01

    We used light confinement in optical microcavities to achieve a strong enhancement and a precise wavelength tunability of the electrical photoconductance of nanostructured porous silicon (PS). The devices consist of a periodic array of alternating PS layers, electrochemically etched to have high and low porosities - and therefore distinct dielectric functions. A central layer having a doubled thickness breaks up the symmetry of the one-dimensional photonic structure, producing a resonance in the photonic band gap that is clearly observed in the reflectance spectrum. The devices were transferred to a glass coated with a transparent SnO{sub 2} electrode, while an Al contact was evaporated on its back side. The electrical conductance was measured as a function of the photon energy. A strong enhancement of the conductance is obtained in a narrow (17nm FWHM) band peaking at the resonance. We present experimental results of the angular dependence of this photoconductance peak energy, and propose an explanation of the conductivity behaviour supported by calculations of the internal electromagnetic field. These devices are promising candidates for finely tuned photoresistors with potential application as chemical sensors and biosensors.

  5. Preparation and Gas Adsorption of Porous Materials from Molecular Precursors

    DEFF Research Database (Denmark)

    Hu, Xinming

    ABSTRACT This thesis deals with the synthesis of porous materials and their applications in gas adsorption. The thesis consists of eight chapters as follows: The first two chapters provide a brief introduction to porous materials and gas adsorption. Chapter 1 gives an overview of construction...... and characteristics of various porous materials, including activated carbons, zeolites, metal-organic frameworks (MOFs), covalent organic frameworks (COFs), and organic porous polymers (POPs). Chapter 2 briefly introduces gas adsorption theory, such as physical and chemical adsorption, adsorption isotherms...

  6. Preparation of carbon monoliths having tailored pore structure from porous polymer precursors

    Energy Technology Data Exchange (ETDEWEB)

    Lagasse, R.R.

    1993-04-01

    This work concerns preparing tailored porous carbon monoliths by pyrolyzing porous polymer precursors. Prior work in this laboratory (1) demonstrated that a low density (0.05 g/cm{sup 3}), high void fraction (97 vol%) carbon monolith could be prepared by pyrolyzing a porous poly(acrylonitrile) (PAN) precursor. A higher density, more robust carbon material is preferred for certain applications, such as electrodes for electrochemical devices. The present work demonstrates that porous carbon monoliths having mass density of 0.7 g/cm{sup 3} can be prepared from a porous PAN precursor if the pyrolysis is controlled carefully. The macropore structure of the carbon is adjusted by changing the pore structure of the PAN precursor, and the finer scale structure (such as the crystallite size L{sub c}) is adjusted by varying the pyrolysis or heat treatment temperature.

  7. Preparation of carbon monoliths having tailored pore structure from porous polymer precursors

    Energy Technology Data Exchange (ETDEWEB)

    Lagasse, R.R.

    1993-01-01

    This work concerns preparing tailored porous carbon monoliths by pyrolyzing porous polymer precursors. Prior work in this laboratory (1) demonstrated that a low density (0.05 g/cm[sup 3]), high void fraction (97 vol%) carbon monolith could be prepared by pyrolyzing a porous poly(acrylonitrile) (PAN) precursor. A higher density, more robust carbon material is preferred for certain applications, such as electrodes for electrochemical devices. The present work demonstrates that porous carbon monoliths having mass density of 0.7 g/cm[sup 3] can be prepared from a porous PAN precursor if the pyrolysis is controlled carefully. The macropore structure of the carbon is adjusted by changing the pore structure of the PAN precursor, and the finer scale structure (such as the crystallite size L[sub c]) is adjusted by varying the pyrolysis or heat treatment temperature.

  8. AP的安全制备%Safe Preparations of Fine Ammonium Perchlorate Particles

    Institute of Scientific and Technical Information of China (English)

    Makoto Kohga

    2006-01-01

    Fine AP particles are required to manufacture the AP-based composite propellants with a wide burning rate range for various applications,especially high burning rate propellants. However,it is difficult to prepare a fine AP safely. Some safe methods for preparing the fine AP particles are reported such as the spray-dry method and freeze-dry method. It is shown that the crystal habit modified AP particle is an effective oxidizer to enhance the burning rate.

  9. Ultra-thin films with highly absorbent porous media fine-tunable for coloration and enhanced color purity.

    Science.gov (United States)

    Yoo, Young Jin; Lim, Jin Ha; Lee, Gil Ju; Jang, Kyung-In; Song, Young Min

    2017-03-02

    We demonstrate ultra-thin, fine-tunable optical coatings with enhanced color purity based on highly absorbent porous media on a metal substrate. We show that the color range provided by these ultra-thin film coatings can be extended by making the absorptive dielectric layer porous. Oblique angle deposition (OAD) of a thin (10-25 nm) germanium (Ge) film by e-beam evaporation onto a thick gold substrate yields controlled porosity. Reflectance spectra and color representations from both calculations and experiments verify the enhancement of resonance tunability and color purity in the nano-tailored coatings. Angle independent reflection properties, and the applicability of such porous Ge on various metal substrates, indicate the strength of these concepts.

  10. Helping Preschoolers Prepare for Writing: Developing Fine Motor Skills

    Science.gov (United States)

    Huffman, J. Michelle; Fortenberry, Callie

    2011-01-01

    Early childhood is the most intensive period for the development of physical skills. Writing progress depends largely on the development of fine motor skills involving small muscle movements of the hand. Young children need to participate in a variety of developmentally appropriate activities intentionally designed to promote fine motor control.…

  11. Preparation and Characterization of Novel Porous Fe-Si Alloys

    Institute of Scientific and Technical Information of China (English)

    WANG Jiefeng; HE Yuehui; JIANG Yao; GAO Hanyan; YANG Junsheng; GAO Lin

    2016-01-01

    Porous Fe-Si alloys with different nominal compositions ranging from Fe-10wt% Si to Fe-50wt% Si were fabricated through a reactive synthesis of Fe and Si elemental powder mixtures. The effects of Si contents on the pore structure of porous Fe-Si alloy were investigated in detail. The results showed that the open porosity, gas permeability and maximum pore size of the porous Fe-Si alloys increased with increasing Si contents, indicating that the porosity and pore size can be tailored by changing the Si contents. The pore structure parameter including the open porosity, gas permeability, maximum pore size obeyed the Hagen-Poiseuille formula with the constant G=0.035 m-1Pa-1s-1 for the reactively synthesized porous Fe-Si alloys. The mechanical property of the porous Fe-Si alloys showed applicability in the ifltration industries.

  12. Preparation and Enzymatic Degradation of Porous Crosslinked Polylactides of Biomass Origin

    Directory of Open Access Journals (Sweden)

    Yuya Kido

    2014-06-01

    Full Text Available To understand the enzymatic degradation behavior of crosslinked polylactide (PLA, the preparation and enzymatic degradation of both thermoplastic (linear and crosslinked PLAs that have pore structures with different dimensions were carried out. The porous structures of the linear PLA samples were of micro and nanoporous nature, and prepared by batch foaming with supercritical CO2 and compared with the porous structures of crosslinked PLA (Lait-X created by the salt leaching method. The surface and cross-sectional morphologies of the porous structures were investigated by using scanning electron microscopy. The morphological analysis of porous Lait-X showed a rapid loss of physical features within 120 h of exposure to proteinase-K enzymatic degradation at 37 °C. Due to the higher affinity for water, enhanced enzymatic activity as compared to the linear PLA porous structures in the micro and nanoporous range was observed.

  13. Preparation and Enzymatic Degradation of Porous Crosslinked Polylactides of Biomass Origin

    Science.gov (United States)

    Kido, Yuya; Sakai, Reika; John, Baiju; Okamoto, Masami; Seppälä, Jukka V.

    2014-01-01

    To understand the enzymatic degradation behavior of crosslinked polylactide (PLA), the preparation and enzymatic degradation of both thermoplastic (linear) and crosslinked PLAs that have pore structures with different dimensions were carried out. The porous structures of the linear PLA samples were of micro and nanoporous nature, and prepared by batch foaming with supercritical CO2 and compared with the porous structures of crosslinked PLA (Lait-X) created by the salt leaching method. The surface and cross-sectional morphologies of the porous structures were investigated by using scanning electron microscopy. The morphological analysis of porous Lait-X showed a rapid loss of physical features within 120 h of exposure to proteinase-K enzymatic degradation at 37 °C. Due to the higher affinity for water, enhanced enzymatic activity as compared to the linear PLA porous structures in the micro and nanoporous range was observed. PMID:24893222

  14. Process for preparing fine grain silicon carbide powder

    Science.gov (United States)

    Wei, G.C.

    Method of producing fine-grain silicon carbide powder comprises combining methyltrimethoxysilane with a solution of phenolic resin, acetone and water or sugar and water, gelling the resulting mixture, and then drying and heating the obtained gel.

  15. Preparation of bioactive porous HA/PCL composite scaffolds

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, J.; Guo, L.Y.; Yang, X.B. [Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Weng, J. [Key Laboratory of Advanced Technologies of Materials (Ministry of Education), School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China)], E-mail: jweng@swjtu.cn

    2008-12-30

    Porous hydroxyapatite (HA) bioceramic scaffold has been widely attracted the attention to act as a three-dimensional (3D) template for cell adhesion, proliferation, differentiation and thus promoting bone and cartilage regeneration because of its osteoinduction. However, the porous bioceramic scaffold is fragile so that it is not suitable to be applied in clinic for bone repair or replacement. Therefore, it is significant to improve the mechanical property of porous HA bioceramics while the interconnected structure is maintained for tissue ingrowth in vivo. In the present research, a porous composite scaffold composed of HA scaffold and polycaprolactone (PCL) lining was fabricated by the method of polymer impregnating to produce HA scaffold coated with PCL lining. Subsequently, the composite scaffolds were deposited with biomimetic coating for improving the bioactivity. The HA/PCL composite scaffolds with improved mechanical property and bioactivity is expected to be a promising bone substitute in tissue engineering applications.

  16. Preparation of bioactive porous HA/PCL composite scaffolds

    Science.gov (United States)

    Zhao, J.; Guo, L. Y.; Yang, X. B.; Weng, J.

    2008-12-01

    Porous hydroxyapatite (HA) bioceramic scaffold has been widely attracted the attention to act as a three-dimensional (3D) template for cell adhesion, proliferation, differentiation and thus promoting bone and cartilage regeneration because of its osteoinduction. However, the porous bioceramic scaffold is fragile so that it is not suitable to be applied in clinic for bone repair or replacement. Therefore, it is significant to improve the mechanical property of porous HA bioceramics while the interconnected structure is maintained for tissue ingrowth in vivo. In the present research, a porous composite scaffold composed of HA scaffold and polycaprolactone (PCL) lining was fabricated by the method of polymer impregnating to produce HA scaffold coated with PCL lining. Subsequently, the composite scaffolds were deposited with biomimetic coating for improving the bioactivity. The HA/PCL composite scaffolds with improved mechanical property and bioactivity is expected to be a promising bone substitute in tissue engineering applications.

  17. Preparation and Gas Adsorption of Porous Materials from Molecular Precursors

    DEFF Research Database (Denmark)

    Hu, Xinming

    ABSTRACT This thesis deals with the synthesis of porous materials and their applications in gas adsorption. The thesis consists of eight chapters as follows: The first two chapters provide a brief introduction to porous materials and gas adsorption. Chapter 1 gives an overview of construction...... and characteristics of various porous materials, including activated carbons, zeolites, metal-organic frameworks (MOFs), covalent organic frameworks (COFs), and organic porous polymers (POPs). Chapter 2 briefly introduces gas adsorption theory, such as physical and chemical adsorption, adsorption isotherms...... rise to significant red-shift of absorption/emission and reduction of fluorescence lifetime and quantum yield Transition-metal-catalyzed and organolithium-mediated reactions provide polymers with only macroporous interparticle voids and thus very low surface areas (4−51 m2 g−1). Attempts have been also...

  18. [Preparation of porous ceramics based on waste ceramics and its Ni2+ adsorption characteristics].

    Science.gov (United States)

    Zhang, Yong-Li; Wang, Cheng-Zhi; Shi, Ce; Shang, Ling-Ling; Ma, Rui; Dong, Wan-Li

    2013-07-01

    The preparation conditions of porous ceramics were determined by SEM, XRD and FT-IR characterizations as well as the nickel removal ability of porous ceramics to be: the mass fraction w of sesbania powder doped was 4%, and the calcination temperature was 800 degrees C. SEM and pore structure characterization illustrated that calcination caused changes in the structure and morphology of waste ceramics. With the increase of calcination temperature, the specific surface area and pore volume decreased, while the aperture increased. EDS analyses showed that the main elements of both the original waste porcelain powder and the porous ceramics were Si, Al and O. The SEM, XRD and FT-IR characterization of porous ceramics illustrated that the structure of porous ceramics was stable before and after adsorption. The series of experiments of Ni2+ adsorption using these porous ceramics showed that when the dosage of porous ceramics was 10 g x L(-1), the adsorption time was 60 min, the pH value was 6.32, and the concentration of nickel-containing wastewater was below 100 mg x L(-1), the Ni2+ removal of wastewater reached 89.7%. Besides, the porous ceramics showed higher removal efficiency on nickel in the wastewater. The Ni(2+)-containing wastewater was processed by the porous ceramics prepared, and the adsorption dynamics and adsorption isotherms of Ni2+ in wastewater by porous ceramics were investigated. The research results showed that the Ni2+ adsorption process of porous ceramics was in accordance with the quasi second-order kinetic model (R2 = 0.999 9), with Q(e) of 9.09 mg x g(-1). The adsorption process can be described by the Freundlich equation and Langmuir equation, and when the temperature increased from 20 degrees C to 40 degrees C, the maximum adsorption capacity Q(m) increased from 14.49 mg x g(-1) to 15.38 mg x g(-1).

  19. Porous cellulose spheres: Preparation, modification and adsorption properties.

    Science.gov (United States)

    Ma, Xiaofei; Liu, Congzhi; Anderson, Debbie P; Chang, Peter R

    2016-12-01

    Porous cellulose spheres (PCS) were fabricated by precipitating the spheres from a cellulose ionic liquid solution, followed by freezing, solvent exchange, and drying. PCS had low crystallinity and a large surface area that facilitated modification with trisodium trimetaphosphate (STMP) to introduce phosphate ester groups into the porous structure of the heterogeneous system. The STMP-modified PCS (SPCS) were used to remove heavy metal ions from aqueous solution. With increasing STMP dosage, the adsorption capacity of SPCS obviously improved due to chelation between Pb(2+) and phosphate ester groups. The kinetic adsorption and isotherm data matched the pseudo-second order model and the Langmuir model well. The maximum adsorption capacity reached 150.6 mg g(-1) for SPCS. SPCS were competitive with other absorbents because the phosphate ester groups and porous structure contributed to Pb(2+) adsorption. Moreover, SPCS can be regenerated with ethylenediamine tetraacetic acid disodium salt (EDTA) solution for repetitious adsorption of Pb(2+).

  20. Microstructural and mechanical characteristics of porous iron prepared by powder metallurgy.

    Science.gov (United States)

    Capek, Jaroslav; Vojtěch, Dalibor

    2014-10-01

    The demand for porous biodegradable load-bearing implants has been increasing recently. Based on investigations of biodegradable stents, porous iron may be a suitable material for such applications. In this study, we prepared porous iron samples with porosities of 34-51 vol.% by powder metallurgy using ammonium bicarbonate as a space-holder material. We studied sample microstructure (SEM-EDX and XRD), flexural and compressive behaviors (universal loading machine) and hardness HV5 (hardness tester) of the prepared samples. Sample porosity increased with the amount of spacer in the initial mixtures. Only the pore surfaces had insignificant oxidation and no other contamination was observed. Increasing porosity decreased the mechanical properties of the samples; although, the properties were still comparable with human bone and higher than those of porous non-metallic biomaterials and porous magnesium prepared in a similar way. Based on these results, powder metallurgy appears to be a suitable method for the preparation of porous iron for orthopedic applications.

  1. Preparation and characterization of the porous ceramics from fly ash

    Institute of Scientific and Technical Information of China (English)

    REN Xiang-jun; ZHANG Xue-bin; MENG Guang-yao; LIU Xing-qin

    2007-01-01

    Porous ceramics was made from coal fly ash,and the microstructure and other properties were characterized as a function of the amount of the pore-forming agent and firing temperature.The results indicated that the proper sintering temperature for the useful ceramic materials is 1250 ℃.and a liquid-phase was involved in the dansification process.

  2. Modification of the Kozeny-Carman equation to quantify formation damage by fines in clean unconsolidated porous media

    Science.gov (United States)

    Krauss, Eva D.

    Accurately estimating formation permeability as a function of porosity, grain size, and the quantity and structure of fines is important for increasing hydrocarbon extraction from rock formations. Accurate formation permeability estimation can provide insight into the factors that lead to formation damage due to fines deposition. The Kozeny-Carman equation can be used to estimate the permeability of unconsolidated media as a function of porosity and grain size, but does not account for the structure of fines. In this study, I show how incorporating a dimensionless bulk factor into the Kozeny-Carman equation can be used to quantify the permeability reduction resulting from deposition of fines in the pore space. I consider several experimental studies from the literature that use a variety of porosities, fluids, fines (differentiated by diameter and type), porous media, and flow velocities. Results indicate that for all of the experiments analyzed, when other variables are held constant, experiments conducted at higher flow velocity result in less plugging. The bulk value was adjusted in the Kozeny-Carman equation to obtain a line of best fit. The root mean square method was used to obtain the best bulk factor value that calculated a curve which had the best match for the experimental data. Fitted values of the bulk factor were then correlated with the Peclet number to investigate how the structure of fines in the pore space, quantified by the bulk factor, depends on the characteristics of the porous media, the depositing colloids, and the flow velocity. For a particular experimental set, at a lower Peclet Number, higher bulk factors are observed, when diffusive transport dominates, which I speculate results from the presence of more dendritic deposits. At higher Peclet Numbers, lower bulk factors are observed, when advective transport dominates, which I speculate results from deposits that are more compact. By understanding the flow velocity dependence of

  3. Preparation of Ultra-fine Aluminum Nitride in Thermal Plasma

    Institute of Scientific and Technical Information of China (English)

    漆继红; 罗义文; 印永祥; 代晓雁

    2002-01-01

    Ultra-fine aluminum nitride has been synthesized by the evaporation of aluminum powder at atmospheric-pressure nitrogen plasma in a hot-wall reactor. The average size of aluminum nitride particle is 0.11μm measured by scanning electric mirror (SEM), and the purity is at least over 90% evaluated by X-Ray diffraction (XRD). The conversion of Al powder to aluminum nitride is strongly depended on the injection of NH3. Typical experimental parameters such as the feed rate of raw material, the flow rate of ammonia and the position of injecting aluminum powder into the reactor are given.

  4. Preparation and characterisation of light emitting porous semiconductors

    CERN Document Server

    Harris, P J

    1996-01-01

    nanometres resulting in an aspect ratio of the order of 1000:1. These materials studied in this work have been studied with the aid of EXAFS, scanning probe microscopy and Muon spectroscopy in order to determine the local structures. Measurements of the photoluminescence intensity have been taken at the synchrotron radiation facility, (Daresbury Laboratory). These results show that the observed photoluminescence is temperature dependent. The porous silicon samples studied for this work showed photoluminescence in the range yellow to red. The photoluminescence intensity was seen to decrease with an increase in temperature. Correspondingly the peak wavelength shifted (by between 12 and 40 nm) towards the blue end of the spectrum as the temperature was reduced from room temperature to 100 K. Scanning probe microscopy and scanning electron microscopy revealed the presence of structures within the porous matrix of the order of nanometres. This size of structure is consistent with that predicted by quantum mechanic...

  5. Preparing electrochemical active hierarchically porous carbons for detecting nitrite in drinkable water

    KAUST Repository

    Ding, Baojun

    2016-01-13

    A class of hierarchically porous carbons were prepared by a facile dual-templating approach. The obtained samples were characterized by scanning electron microscopy, X-ray diffraction, Raman spectroscopy, Brunaner-Emmett-Teller measurement and electrochemical work station, respectively. The porous carbons could possess large specific surface area, interconnected pore structures, high conductivity and graphitizing degree. The resulting materials were used to prepare integrated modified electrodes. Based on the experimental results, the as-prepared hierarchically porous graphite (HPG) modified electrode showed the best electroactive performances toward the detection of nitrite with a detection limit of 8.1 × 10-3 mM. This HPG electrode was also repeatable and stable for 6 weeks. Moreover, this electrode was used for the determination of nitrite in drinkable water, and had acceptable recoveries. © The Royal Society of Chemistry 2016.

  6. Preparation and Sintering Effect in Quartz-Barium Titanate Porous Ceramics and Permeability Modulation Using an Implanted Electrode

    Directory of Open Access Journals (Sweden)

    Ernesto Suaste Gómez

    2014-01-01

    Full Text Available Barium titanate and quartz mixed in different proportions were used to create porous piezoelectric ceramics. Three different sintering temperatures were used for the ceramics preparation; a nichrome wire was used as internal electrode in porous ceramics. Characteristics as porous area, porosity, and its relationship with quartz percentage and sintering temperatures were studied. Porous ceramics with an implanted electrode were created, by applying an alternating voltage in the internal electrode that controlled the liquid permeability coefficient, calculated by the Darcy Law.

  7. USE OF POROUS BIODEGRADABLE POLYMER IMPLANTS IN MENISCUS RECONSTRUCTION .1. PREPARATION OF POROUS BIODEGRADABLE POLYURETHANES FOR THE RECONSTRUCTION OF MENISCUS LESIONS

    NARCIS (Netherlands)

    DEGROOT, JH; NIJENHUIS, AJ; BRUIN, P; PENNINGS, AJ; VETH, RPH; JANSEN, HWB

    1990-01-01

    Porous biodegradable poly(urethanes) for reconstructing menisci have been prepared using two different combinations of techniques: freeze-drying/salt-leaching and in-situ polymerization/salt-leaching. Using these methods, homogenous porous materials with a controllable and reproducible morphology ca

  8. Preparation and Characterization of Nanotitanium Dioxide Coating Film Doped with Fe3+ Ions on Porous Ceramic

    Institute of Scientific and Technical Information of China (English)

    Kejing Xu

    2005-01-01

    The nanotitanium dioxide (TiO2) photocatalytic and porous ceramic filtering technique is one of the advanced methods to effectively treat organic wastewater. The TiO2 sol doped with Fe3+ ions was prepared by sol-gel processing. The influences of the process conditions of coating nanophotocatalytic material-Fe3+-TiO2 film on the surface of porous ceramic filter by dipping-lift method on the performance of porous ceramic filter were studied. The porous ceramic filters have two functions at the same time,filtration and photocatalytic degradation. The results of this study showed that the pH and viscosity of the sol,amount of Fe3+ ions doped as well as the coating times greatly affect the quality of coating film,the performance parameters and the photocatalytic activity of the porous ceramic filter. When the pH of the sol is 3-4,the viscosity is about 6 mPa·S,the amount of doped Fe3+ ions is about 2.0 g/L,the porous ceramic filter has been shown to have the best filtering performance and photocatalytic activity. In this condition,the porosity of porous ceramic is about 42.5%,the pore diameter is 8-10μm. The degradation of methyl-orange is 74.76% under lighting for 120 min.

  9. Europium-doped amorphous calcium phosphate porous nanospheres: preparation and application as luminescent drug carriers

    Directory of Open Access Journals (Sweden)

    Zhang Kui-Hua

    2011-01-01

    Full Text Available Abstract Calcium phosphate is the most important inorganic constituent of biological tissues, and synthetic calcium phosphate has been widely used as biomaterials. In this study, a facile method has been developed for the fabrication of amorphous calcium phosphate (ACP/polylactide-block-monomethoxy(polyethyleneglycol hybrid nanoparticles and ACP porous nanospheres. Europium-doping is performed to enable photoluminescence (PL function of ACP porous nanospheres. A high specific surface area of the europium-doped ACP (Eu3+:ACP porous nanospheres is achieved (126.7 m2/g. PL properties of Eu3+:ACP porous nanospheres are investigated, and the most intense peak at 612 nm is observed at 5 mol% Eu3+ doping. In vitro cytotoxicity experiments indicate that the as-prepared Eu3+:ACP porous nanospheres are biocompatible. In vitro drug release experiments indicate that the ibuprofen-loaded Eu3+:ACP porous nanospheres show a slow and sustained drug release in simulated body fluid. We have found that the cumulative amount of released drug has a linear relationship with the natural logarithm of release time (ln(t. The Eu3+:ACP porous nanospheres are bioactive, and can transform to hydroxyapatite during drug release. The PL properties of drug-loaded nanocarriers before and after drug release are also investigated.

  10. Preparation of Macro-Porous Tin Oxide for Sensing of Sulfur Compound.

    Science.gov (United States)

    Park, No-Kuk; Lee, Tae Hoon; Sung, Yeon Baek; Kim, Yong Sul; Lee, Tae Jin

    2016-03-01

    Macro-porous tin oxide was prepared as an enhanced sensing material for sulfur compounds, such as hydrogen sulfide. Poly-methyl-methacrylate (PMMA) was used as a template for the formation of macro-pores. Tin chloride was used as a precursor for the synthesis of tin oxide, and was impregnated over PMMA beads using a rotary vacuum evaporator. The solid Sn/PMMA material was treated thermally for 4 h at 600 degrees C. The porous morphology of tin oxide prepared in this study was observed by scanning electron microscopy. The surface area of this material measured by the nitrogen adsorption method was approximately 56 m2/g. The crystal structure of the porous material analyzed by XRD was a typical structure of tin oxide. The response of macro-porous tin oxide as a chemical gas sensor was measured using an I-V source meter and the change in signal was observed with the repeated injection of hydrogen sulfide and air. The sensing tests for macro-porous tin oxide were carried out at 200 degrees C and the fast response of macro-porous sensing material was also confirmed.

  11. Porous Ca-based bead sorbents for simultaneous removal of SO₂, fine particulate matters, and heavy metals from pilot plant sewage sludge incineration.

    Science.gov (United States)

    Han, Yosep; Hwang, Gukhwa; Kim, Donghyun; Park, Soyeon; Kim, Hyunjung

    2015-01-01

    In this study, a porous calcium-based sorbent was prepared for simultaneous removal of SO2, particulate matter (PM), and heavy metals generated during incineration of sewage sludge. The prepared sorbent was confirmed to have a 3-dimensional-network pore structure, a high specific surface area of 68.5m(2)/g, and gas permeability of 1.12 × 10(-10)m(2). Laboratory-scale tests indicated that there was an improvement in the performance of SO2 removal as the porosity and the specific surface area of the sorbent increased. Additionally, increasing reaction temperature led to greater SO2 removal. Meanwhile, the SL-4 and LS-3 sorbents prepared in this study were installed for operation during pilot tests treating the sewage sludge combustion gas generated by a fluidized incinerator in order to compare and evaluate their feasibility for use in industrial applications. The results showed that the reactivity between SO2 and the starting material of the sorbent (Ca(OH)2>CaCO3), as well as the high specific surface area of the sorbent, were confirmed to be critical factors that improved the performance of SO2 removal. Notably, the results confirmed that both fine PM (≤ 1 μm) and heavy metals were simultaneously removed with increasing efficiency over the time of operation.

  12. Preparation of porous silicon carbide from molecular precursors; Preparation de carbure de silicium poreux a partir de precurseurs moleculaires

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, J

    2008-02-15

    The preparation of Porous Silicon Carbide (SiC) from molecular precursors is described in this work. Firstly, poly-silane and poly-carbo-silane were synthesised from targeted molecular precursors TSCH and TCDSCB. The pyrolysis of these polymers under inert conditions gave the SiC. Secondly, the preparation of functional poly-silane was explored. It was shown that Cp{sub 2}Ti(OPh){sub 2} was a suitable catalyst for the preparation of such functional poly-silane in a one-pot process. Finally, macroporous SiC were prepared from hard templating method by using a commercial silica. (author)

  13. A novel strategy for the preparation of porous microspheres and its application in peptide drug loading.

    Science.gov (United States)

    Wei, Yi; Wang, Yuxia; Zhang, Huixia; Zhou, Weiqing; Ma, Guanghui

    2016-09-15

    A new strategy is developed to prepare porous microspheres with narrow size distribution for peptides controlled release, involving a fabrication of porous microspheres without any porogens followed by a pore closing process. Amphiphilic polymers with different hydrophobic segments (poly(monomethoxypolyethylene glycol-co-d,l-lactide) (mPEG-PLA), poly(monomethoxypolyethylene glycol-co-d,l-lactic-co-glycolic acid) (mPEG-PLGA)) are employed as microspheres matrix to prepare porous microspheres based on a double emulsion-premix membrane emulsification technique combined with a solvent evaporation method. Both microspheres possess narrow size distribution and porous surface, which are mainly caused by (a) hydrophilic polyethylene glycol (PEG) segments absorbing water molecules followed by a water evaporation process and (b) local explosion of microspheres due to fast evaporation of dichloromethane (MC). Importantly, mPEG-PLGA microspheres have a honeycomb like structure while mPEG-PLA microspheres have a solid structure internally, illustrating that the different hydrophobic segments could modulate the affinity between solvent and matrix polymer and influence the phase separation rate of microspheres matrix. Long term release patterns are demonstrated with pore-closed microspheres, which are prepared from mPEG-PLGA microspheres loading salmon calcitonin (SCT). These results suggest that it is potential to construct porous microspheres for drug sustained release using permanent geometric templates as new porogens.

  14. Improvement in SOFC anode performance by finely-structured Ni/YSZ cermet prepared via heterocoagulation.

    Science.gov (United States)

    Sunagawa, Yoji; Yamamoto, Katsutoshi; Muramatsu, Atsushi

    2006-03-30

    A novel preparation technique for a nanostructured anode for a solid oxide fuel cell is investigated. By mixing nanometer-sized NiO and YSZ powders in a pH-controlled aqueous media, a fine mixture of nanoparticles is successfully obtained through heterocoagulation. The anode prepared from thus prepared mixture has a large triple phase boundary and shows a great improvement in the anode performance by increasing the electric conductivity and effective surface area.

  15. Optimization of calcium phosphate fine ceramic powders preparation

    Science.gov (United States)

    Sezanova, K.; Tepavitcharova, S.; Rabadjieva, D.; Gergulova, R.; Ilieva, R.

    2013-12-01

    The effect of biomimetic synthesis method, reaction medium and further precursor treatments on the chemical and phase composition, crystal size and morphology of calcium phosphates was examined. Nanosized calcium phosphate precursors were biomimetically precipitated by the method of continuous precipitation in three types of reaction media at pH 8: (i) SBF as an inorganic electrolyte system; (ii) organic (glycerine) modified SBF (volume ratio of 1:1); (iii) polymer (10 g/l xanthan gum or 10 g/l guar gum) modified SBF (volume ratio of 1:1). After maturation (24 h) the samples were lyophilized, calcinated at 300°C for 3 hours, and washed with water, followed by new gelation, lyophilization and step-wise (200, 400, 600, 800, and 1000°C, each for 3 hours) sintering. The reaction medium influenced the chemical composition and particle size but not the morphology of the calcium phosphate powders. In all studied cases bi-phase calcium phosphate fine powders with well-shaped spherical grains, consisting of β-tricalcium phosphate (β-TCP) and hydroxyapatite (HA) with a Ca/P ratio of 1.3 - 1.6 were obtained. The SBF modifiers decreased the particle size of the product in the sequence guar gum ˜ xanthan gum < glycerin < SBF medium.

  16. Drastic difference in porous structure of calcium alginate microspheres prepared with fresh or hydrolyzed sodium alginate.

    Science.gov (United States)

    Akamatsu, Kazuki; Maruyama, Kaho; Chen, Wei; Nakao, Aiko; Nakao, Shin-ichi

    2011-11-15

    Fresh or hydrolyzed sodium alginate was used as a material for preparing calcium alginate microspheres, and a drastic difference in porous structure was observed between them, even though the other materials and the preparation method except for the sodium alginate were exactly the same. When fresh sodium alginate was used, nonporous microspheres were obtained. In contrast, when 82-day-hydrolyzed sodium alginate, whose molecular weight became 7% of the molecular weight of the fresh sodium alginate, was used, porous microspheres with 6.5 times larger BET surface area were obtained. XPS studies indicated that the atomic ratio of Ca, the crosslinker of the alginic acid polymer, was almost the same in both cases. Therefore, the difference in porous structure was not attributed to the amount of crosslinking points, but to the low-molecular-weight compounds formed by hydrolysis, and they would work as pore-generating agents. Copyright © 2011 Elsevier Inc. All rights reserved.

  17. Preparation of porous titanium oxide films onto indium tin oxide for application in organic photovoltaic devices

    Energy Technology Data Exchange (ETDEWEB)

    Macedo, Andreia G. [Laboratorio de Dispositivos Nanoestruturados, Departamento de Fisica, Universidade Federal do Parana, Curitiba, Parana (Brazil); Mattos, Luana L.; Spada, Edna R.; Serpa, Rafael B.; Campos, Cristiani S. [Laboratorio de Sistemas Nanoestruturados, Departamento de Fisica, Universidade Federal de Santa Catarina, Florianopolis, Santa Catarina (Brazil); Grova, Isabel R.; Ackcelrud, Leni [Laboratorio de Polimeros Paulo Scarpa, Departamento de Quimica, Universidade Federal do Parana, Curitiba, Parana (Brazil); Reis, Francoise T.; Sartorelli, Maria L. [Laboratorio de Sistemas Nanoestruturados, Departamento de Fisica, Universidade Federal de Santa Catarina, Florianopolis, Santa Catarina (Brazil); Roman, Lucimara S., E-mail: lsroman@fisica.ufpr.br [Laboratorio de Dispositivos Nanoestruturados, Departamento de Fisica, Universidade Federal do Parana, Curitiba, Parana (Brazil)

    2012-05-01

    In this work, porous ordered TiO{sub 2} films were prepared through sol gel route by using a monolayer of polystyrene spheres as template on indium-tin oxide/glass substrate. These films were characterized by SEM, AFM, Raman spectroscopy, UV-vis absorbance and XRD. The UV-vis absorbance spectrum show a pseudo band gap (PBG) with maxima at 460 nm arising from the light scattering and partial or total suppression of the photon density of states, this PBG can be controlled by the size of the pore. We also propose the use of this porous film as electron acceptor electrode in organic photovoltaic cells; we show that devices prepared with porous titania displayed higher efficiencies than devices using compact titania films as electrode. Such behaviour was observed in both bilayer and bulk heterojunction devices.

  18. Preparation of Porous Biodegradable Polymer and Its Nanocomposites by Supercritical CO2 Foaming for Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Xia Liao

    2012-01-01

    Full Text Available Using supercritical carbon dioxide (scCO2 as an alternative to conventional methods in the preparation of porous biodegradable polymer and polymer/nanocomposites for tissue engineering has attracted increasing interest in recent years due to the absence of using organic solvents and the ability to incorporate thermosensitive biologicals without loss of bioactivity. Additionally, scCO2 can exert a high level of control over porosity and morphology of scaffolds by tuning the processing parameters. This paper describes the newly achievements on the preparation of porous polymer materials using scCO2 foaming technology with focus on the porous biodegradable materials and its nanocomposites relevant to tissue engineering.

  19. A novel gel combustion procedure for the preparation of foam and porous pellets of UO2

    Science.gov (United States)

    Sanjay Kumar, D.; Ananthasivan, K.; Venkata Krishnan, R.; Maji, Dasarath; Dasgupta, Arup

    2017-01-01

    In this study, it has been demonstrated for the first time how sucrose gel-combustion could be used for the preparation of UO2 foam. Further the citrate gel-combustion was gainfully used for preparing porous pellets of UO2. The utility of two-step sintering (1073 K for 30 min and 1473 K for 4 h) for obtaining these porous bodies was demonstrated for the first time. The foams and pellets possessed meso and macro pores. A starting mixture with sucrose to nitrate ratio of 2.4 was found to yield urania foam with adequate crush strength. The porous pellets were found to possess better handling strength, lesser carbon residue and higher overall density than the foam. A citric acid to nitrate ratio 0.25 in the starting mixture, 180 MPa compaction pressure were optimal for obtaining a pellet with 40% porosity.

  20. Development of measuring apparatus for monitoring the preparation of fines

    Energy Technology Data Exchange (ETDEWEB)

    Bechmann, C.; Fauth, G.; Luedke, H.; Schieder, T.

    1984-01-01

    Monitoring or controlling a preparation process requires a sufficiently precise knowledge of the raw material characteristics and also high-speed automatic analysis by measuring apparatus of the quantities and properties of bulk materials and pulpflows. Such apparatus includes devices to measure ash content of pulps, concentration of solids, grain size or grain size distribution and pulp flow. For monitoring flotation, radiometric analysis of the ash content of pulps using the transmission method was tested in a semi-industrial plant. The radioactive sources used were Americium 241 and Caesium 137. The residual standard deviation compared with manual sampling was about 1 g/l for the solids concentration and around 0.4% for ash content. As regards the measurement of grain size and grain size distribution, optical methods have proved to be unsuitable for operational use in coal preparation plants. The ultrasonic absorption method requires further basic research. For short time-interval measurement of pulp flows using devices requiring no conversion, the devices based on the ultrasonic Doppler effect did not yield satisfactory results during operational testing in spite of the accuracy achieved on the test rig. For monitoring washery water thickeners, measuring by means of photometric devices has proved to be suitable for operational use.

  1. In vitro study on porous silver scaffolds prepared by electroplating method using cellular carbon skeleton as the substrate

    Energy Technology Data Exchange (ETDEWEB)

    Guo, M.; Wang, X.; Zhou, H.M.; Li, L. [Center for Biomedical Materials and Engineering, Harbin Engineering University, Harbin 150001 (China); Nie, F.L. [Department of Advanced Materials and Nanotechnology, College of Engineering, Peking University, Beijing 100871 (China); Cheng, Y. [Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871 (China); Zheng, Y.F., E-mail: yfzheng@pku.edu.cn [Center for Biomedical Materials and Engineering, Harbin Engineering University, Harbin 150001 (China); Department of Advanced Materials and Nanotechnology, College of Engineering, Peking University, Beijing 100871 (China)

    2012-05-01

    Porous silver scaffolds, with the porosity ranging from 68% to 81% and the apparent density ranging from 0.4 to 1 g Dot-Operator cm{sup -3} were prepared by electroplating method using cellular carbon skeleton as the substrate. The microstructure, mechanical property, cytotoxicity and antibacterial activity of the prepared porous silver scaffold were studied. The present porous silver scaffolds had a highly three-dimensional trabecular porous structure with the porosity and the apparent density close to that of the cancellous bone. Furthermore, the mechanical property such as elastic modulus and yield strength of the porous silver scaffolds were lower than that of commercial available porous Ti and porous Ti alloys but much closer to that of the cancellous bone and porous Ta. In addition, study of in vitro behavior showed that the porous silver scaffold possessed significant antibacterial capability of inhibition of bacterial proliferation and adherence against Staphylococcus aureus and Staphylococcus epidermidis, and little cytotoxicity to Mg-63 cell line and NIH-3T3 cell line. Consequently, the porous silver scaffolds prepared by electrodeposition possess a promising application for bone implants. - Highlights: Black-Right-Pointing-Pointer Porous Ag scaffolds were produced by electroplating Ag on cellular carbon skeleton. Black-Right-Pointing-Pointer Porous Ag scaffolds have the porosity 68-81% and the apparent density 0.4-1 g Dot-Operator cm{sup -3}. Black-Right-Pointing-Pointer The mechanical property of porous Ag is close to cancellous bone and porous Ta. Black-Right-Pointing-Pointer Porous Ag inhibits the proliferation and adherence of S. aureus and S. epidermidis.

  2. Preparation and Characterization of Nano-polymer Porous MgO

    Institute of Scientific and Technical Information of China (English)

    Xue Liang ZHAI; Ai Dong ZHAO; Mi Ying JIA

    2004-01-01

    Porous carrier MgO which was aggregated by nano-particles has been firstly prepared by using a normal technology route. The MgO was rod-shaped and had large surface area. The factors which affect grain size and microstructure of MgO were explored.

  3. Transmission Electron Microscopy Specimen Preparation Method for Multiphase Porous Functional Ceramics

    DEFF Research Database (Denmark)

    Zhang, Wei; Kuhn, Luise Theil; Jørgensen, Peter Stanley

    2013-01-01

    An optimum method is proposed to prepare thin foil transmission electron microscopy (TEM) lamellae of multiphase porous functional ceramics: prefilling the pore space of these materials with an epoxy resin prior to focused ion beam milling. Several advantages of epoxy impregnation are demonstrate...

  4. Modelling and analysis of CVD processes in porous media for ceramic composite preparation

    NARCIS (Netherlands)

    Lin, Y.S.; Burggraaf, A.J.

    1991-01-01

    A continuum phenomenological model is presented to describe chemical vapour deposition (CVD) of solid product inside porous substrate media for the preparation of reinforced ceramic-matrix composites [by the chemical vapour infiltration (CVI) process] and ceramic membrane composites (by a modified C

  5. Porous silicon nanoparticles for nanomedicine: preparation and biomedical applications.

    Science.gov (United States)

    Santos, Hélder A; Mäkilä, Ermei; Airaksinen, Anu J; Bimbo, Luis M; Hirvonen, Jouni

    2014-04-01

    The research on porous silicon (PSi) materials for biomedical applications has expanded greatly since the early studies of Leigh Canham more than 25 years ago. Currently, PSi nanoparticles are receiving growing attention from the scientific biomedical community. These nanostructured materials have emerged as promising multifunctional and versatile platforms for nanomedicine in drug delivery, diagnostics and therapy. The outstanding properties of PSi, including excellent in vivo biocompatibility and biodegradability, have led to many applications of PSi for delivery of therapeutic agents. In this review, we highlight current advances and recent efforts on PSi nanoparticles regarding the production properties, efficient drug delivery, multidrug delivery, permeation across biological barriers, biosafety and in vivo tracking for biomedical applications. The constant boost on successful preclinical in vivo data reported so far makes this the 'golden age' for PSi, which is expected to finally be translated into the clinic in the near future.

  6. Preparation and Thermal Characterization of Annealed Gold Coated Porous Silicon

    Directory of Open Access Journals (Sweden)

    Afarin Bahrami

    2012-01-01

    Full Text Available Porous silicon (PSi layers were formed on a p-type Si wafer. Six samples were anodised electrically with a 30 mA/cm2 fixed current density for different etching times. The samples were coated with a 50–60 nm gold layer and annealed at different temperatures under Ar flow. The morphology of the layers, before and after annealing, formed by this method was investigated by scanning electron microscopy (SEM. Photoacoustic spectroscopy (PAS measurements were carried out to measure the thermal diffusivity (TD of the PSi and Au/PSi samples. For the Au/PSi samples, the thermal diffusivity was measured before and after annealing to study the effect of annealing. Also to study the aging effect, a comparison was made between freshly annealed samples and samples 30 days after annealing.

  7. Structural and optical characteristics of porous InAlGaN prepared by photoelectrochemical etching

    Energy Technology Data Exchange (ETDEWEB)

    Radzali, R., E-mail: rosfariza074@ppinang.uitm.edu.my [Nano-Optoelectronics Research and Technology Laboratory, School of Physics, Universiti Sains Malaysia, 11800 Penang (Malaysia); Faculty of Electrical Engineering, Universiti Teknologi MARA, Jalan Permatang Pauh, 13500 Permatang Pauh, Pulau Pinang (Malaysia); Hassan, Z., E-mail: zai@usm.my [Nano-Optoelectronics Research and Technology Laboratory, School of Physics, Universiti Sains Malaysia, 11800 Penang (Malaysia); Zainal, N., E-mail: norzaini@usm.my [Nano-Optoelectronics Research and Technology Laboratory, School of Physics, Universiti Sains Malaysia, 11800 Penang (Malaysia); Yam, F.K., E-mail: yamfk@usm.my [Nano-Optoelectronics Research and Technology Laboratory, School of Physics, Universiti Sains Malaysia, 11800 Penang (Malaysia)

    2015-02-15

    Highlights: • Porous InAlGaN was successfully fabricated by photoelectrochemical etching for the first time. • Etching time influenced the pore density and surface roughness of the sample. • Reduction of dislocation density and strain were observed in the porous samples. - Abstract: The effect of etching duration on the porous structure of quaternary III-nitride alloy, InAlGaN prepared using the photoelectrochemical etching technique was evaluated in this study. Field emission scanning electron microscopy (FE-SEM) revealed that the pore density of the sample increased with increased etching duration, as did the root mean square (RMS) roughness, as measured by atomic force microscopy (AFM). The high resolution X-ray diffraction (HR-XRD) rocking curve measurement showed that dislocation density was reduced in samples etched for 15 and 20 min. In the Raman spectra, the InGaN-like E{sub 2}(high) phonon mode of porous InAlGaN samples exhibited red shift characteristic relative to the non-porous sample due to relaxation of compressive stress of the porous sample. These results illustrate that etching duration affects the structural and optical properties of the InAlGaN sample.

  8. Preparation of Porous Alumina Film on Aluminum Substrate by Anodization in Oxalic Acid

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Self-ordering of the cell arrangement of the anodic porous alumina was prepared in oxalic acid solution at a constant potential of 40V and at a temperature of 20°C. The honeycomb structure made by one step anodization method and two step anodization method is different.Pores in the alumina film prepared by two step anodization method were more ordered than those by one step anodization method.

  9. Facile preparation of nitrogen-doped hierarchical porous carbon with high performance in supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Kun [State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou 730050 (China); Kong, Ling-Bin, E-mail: konglb@lut.cn [State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou 730050 (China); School of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou 730050 (China); Shen, Kui-Wen; Dai, Yan-Hua; Shi, Ming; Hu, Bing [State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou 730050 (China); Luo, Yong-Chun; Kang, Long [School of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou 730050 (China)

    2016-02-28

    Graphical abstract: Preparing and activating process of nitrogen-doped hierarchical porous carbon (NHPC). - Highlights: • The well-defined PAN-b-PMMA copolymer was synthesized by atom transfer radical polymerization with narrow molecular weight distribution. • Nitrogen-doped hierarchical porous structure (NHPC) was prepared through a simple carbonization procedure of PAN-b-PMMA precursor. • NHPC possessed hierarchical porous structure with high BET surface area of 257 m{sup 2} g{sup −1} and DFT mesopore size of 14.61 nm. • Effects of activation conditions on supercapacitive behavior were systematically studied. - Abstract: The nitrogen-doped hierarchical porous carbon (NHPC) material was successfully prepared through a simple carbonization procedure of well-defined diblock copolymer precursor containing nitrogen-enriched carbon source, i.e., polyacrylonitrile (PAN), and asacrificial block, i.e., polymethylmethacrylate (PMMA). PAN-b-PMMA diblock copolymer was synthesized by atom transfer radical polymeriation (ATRP) with narrow molecular weight distribution. The as-obtained NHPC possessed nitrogen-doped hierarchical porous structure with high BET surface area of 257 m{sup 2} g{sup −1} and Nonlocal density functional theory (NLDFT) mesopore size of 14.61 nm. Surface activated nitrogen-doped hierarchical porous carbon (A-NHPC) materials were obtained by subsequent surface activation with HNO{sub 3} solution. The effects of activation conditions on supercapacitive behavior were systematically studied, a maximum specific capacitance of 314 F g{sup −1} at a current density of 0.5 A g{sup −1} was achieved in 2 M KOH aqueous electrolyte. Simultaneously, it exhibited excellent rate capability of 67.8% capacitance retention as the current density increased from 0.5 to 20 A g{sup −1} and superior cycling performance of 90% capacitance retention after 10,000 cycles at the current density of 2 A g{sup −1}.

  10. Preparation and photo-catalytic activity of TiO2-coated medical stone-based porous ceramics

    Science.gov (United States)

    Gao, Ru-qin; Hou, Xin-mei

    2013-06-01

    Medical stone-based porous ceramics as a carrier were prepared by ultra-fine grinding and low-temperature sintering method. Nano-TiO2 thin films were loaded on the carrier by chemical liquid deposition method using titanium tetrachloride as a precursor. The micro-morphology and microstructure of the synthesized samples were characterized using X-ray diffraction, scanning electron microscopy with energy dispersive spectrometry, and mercury injection method. The photo-catalytic activity of the TiO2 thin films was investigated by degrading formaldehyde. The main crystalline phase in the TiO2 thin films calcined at 550°C is anatase with the average particle size about 10 nm. The specific surface area of the carrier-coated nano-TiO2 increases from 3.68 to 5.32 m2/g. The formaldehyde removal rate of the TiO2/medical stone-based porous ceramics irradiated under an ultraviolet lamp for 120 min reaches 85.6%.

  11. An Approach for Preparation of Porous Silicon/Rare Earth Hybrid——Immersion Method

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiaoxia; CHEN Ning; SHI Jianxin; GONG Menglian; ZHANG Jianhua; WANG Di

    2009-01-01

    A simple but effective doping method,immersion method,was presented.Rare earth complexes[Na_3Tb(DPA)_3·9H_2O and Na_3Eu(DPA)_3·9H_2O]were introduced into porous silicon(PS),where H_2DPA is 2,6-dicarboxy pyridine acid.Rare earths were proved to dope into PS effectively by photoluminescence(PL)and X-ray energy dispersive spectroscopy(EDS).And the prepared hybrid samples of PS/RE were found to emit intense room-temperature red and green luminescence while the luminescence of porous silicon are almost thoroughly quenched.

  12. Preparation and Microstructure of Porous ZrB2 Ceramics Using Reactive Spark Plasma Sintering Method

    Institute of Scientific and Technical Information of China (English)

    YUAN Huiping; LI Junguo; SHEN Qiang; ZHANG Lianmeng

    2015-01-01

    Zirconium oxide (ZrO2) and boron carbide (B4C) were added to ZrB2 raw powders to prepare ZrB2 porous ceramics by reactive spark plasma sintering (RSPS). The reactions between ZrO2 and B4C which produce ZrB2 and gas (such as CO and B2O3) result in pore formation. X-Ray Diffraction results indicated that the products phase was ZrB2 and the reaction was completed after the RSPS process. The porosity could be controlled by changing the ratio of synthesized ZrB2 to raw ZrB2 powders. The porosity of porous ceramics with 20 wt% and 40 wt% synthsized ZrB2 are 0.185 and 0.222, respectivly. And dense ZrB2-SiC ceramic with a porosity of 0.057 was prepared under the same conditions for comparison. The pores were homogeneously distributed within the microstructure of the porous ceramics. The results indicate a promising method for preparing porous ZrB2-based ceramics.

  13. Preparation and properties of highly porous, biomorphic YSZ ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Rambo, C.R.; Cao, J.; Sieber, H

    2004-10-15

    Highly porous, biomorphic YSZ (yttria-stabilized zirconia) ceramics were manufactured by infiltration of zirconium-oxychloride (ZrOCl{sub 2}{center_dot}8H{sub 2}O) sol into biological template structures derived from rattan and pine wood. 3-5 mol% yttrium nitrate (Y(NO{sub 3}){sub 3}{center_dot}5H{sub 2}O) was added to the sol to stabilize the tetragonal ZrO{sub 2} phase. After vacuum-assisted infiltration, the specimens were pyrolysed at 800 deg. C in N{sub 2} atmosphere. Repeated infiltrations and subsequent annealing in air at temperatures up to 1550 deg. C yields the burn out of the biocarbon template and resulted in the formation of biomorphous YSZ ceramics, which maintained the microstructural features of the biological preform. Depending on the type of the biological template as well as the processing parameters, biomorphic ZrO{sub 2} ceramics with an unidirected pore morphology and a large variety of microstructures can be obtained.

  14. Classification mechanism of the chute, a liquid-phase remover of fines in the micrometre range from a batch of porous particles

    NARCIS (Netherlands)

    Jonker, G.H.; Hoffmann, A.C; Beenackers, A.A C M

    1997-01-01

    A simple and effective classification method, the 'chute', has been developed for the liquid-phase removal of fines from a batch of porous (catalyst) particles in the micrometre range. The chute is a continuous sedimentation fractionator, working in the gravitational field. Equations based an the se

  15. A foaming process to prepare porous polymer membrane for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Li, Z.H. [Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, College of Chemistry, Xiangtan University, Hunan 411105 (China); New Energy and Materials Laboratory (NEML), Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433 (China)], E-mail: lzh69@xtu.edu.cn; Cheng, C.; Zhan, X.Y. [Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, College of Chemistry, Xiangtan University, Hunan 411105 (China); Wu, Y.P. [New Energy and Materials Laboratory (NEML), Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433 (China)], E-mail: wuyp@fudan.edu.cn; Zhou, X.D. [State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai 200237 (China)

    2009-07-15

    A foaming process was used to prepare porous polymer membranes (PPMs) based on poly(vinylidene diflouride-co-hexafluoropropylene) copolymer for lithium ion batteries. In this simple process, urea, the foaming agent, was decomposed into gases and was removed at an elevated temperature to get the porous structure within the polymer matrix. When the weight ratio of urea to P(VDF-HFP) is 5:6, the PPM presents the highest porosity, 70.2%, and the prepared gelled polymer electrolyte shows an ionic conductivity up to 1.43 x 10{sup -3} S cm{sup -1} at room temperature. This provides another way to prepare gelled polymer electrolytes easily for application in rechargeable lithium batteries.

  16. Porous carbon material containing CaO for acidic gas capture: preparation and properties.

    Science.gov (United States)

    Przepiórski, Jacek; Czyżewski, Adam; Pietrzak, Robert; Toyoda, Masahiro; Morawski, Antoni W

    2013-12-15

    A one-step process for the preparation of CaO-containing porous carbons is described. Mixtures of poly(ethylene terephthalate) with natural limestone were pyrolyzed and thus hybrid sorbents could be easily obtained. The polymeric material and the mineral served as a carbon precursor and CaO delivering agent, respectively. We discuss effects of the preparation conditions and the relative amounts of the raw materials used for the preparations on the porosity of the hybrid products. The micropore areas and volumes of the obtained products tended to decrease with increasing CaO contents. Increase in the preparation temperature entailed a decrease in the micropore volume, whereas the mesopore volume increased. The pore creation mechanism is proposed on the basis of thermogravimetric and temperature-programmed desorption measurements. The prepared CaO-containing porous carbons efficiently captured SO2 and CO2 from air. Washing out of CaO from the hybrid materials was confirmed as a suitable method to obtain highly porous carbon materials.

  17. Carbon molecular sieve membranes prepared from porous fiber precursor

    NARCIS (Netherlands)

    Barsema, J.N.; van der Vegt, N.F.A.; Koops, G.H.; Wessling, Matthias

    2002-01-01

    Carbon molecular sieve (CMS) membranes are usually prepared from dense polymeric precursors that already show intrinsic gas separation properties. The rationale behind this approach is that the occurrence of any kind of initial porosity will deteriorate the final CMS performance. We will show that

  18. Carbon molecular sieve membranes prepared from porous fiber precursor

    NARCIS (Netherlands)

    Barsema, Jonathan N.; Vegt, van der N.F.A.; Koops, G.H.; Wessling, M.

    2002-01-01

    Carbon molecular sieve (CMS) membranes are usually prepared from dense polymeric precursors that already show intrinsic gas separation properties. The rationale behind this approach is that the occurrence of any kind of initial porosity will deteriorate the final CMS performance. We will show that i

  19. Gold Nanostructures for Surface-Enhanced Raman Spectroscopy, Prepared by Electrodeposition in Porous Silicon

    Directory of Open Access Journals (Sweden)

    Yukio H. Ogata

    2011-04-01

    Full Text Available Electrodeposition of gold into porous silicon was investigated. In the present study, porous silicon with ~100 nm in pore diameter, so-called medium-sized pores, was used as template electrode for gold electrodeposition. The growth behavior of gold deposits was studied by scanning electron microscope observation of the gold deposited porous silicon. Gold nanorod arrays with different rod lengths were prepared, and their surface-enhanced Raman scattering properties were investigated. We found that the absorption peak due to the surface plasmon resonance can be tuned by changing the length of the nanorods. The optimum length of the gold nanorods was ~600 nm for surface-enhanced Raman spectroscopy using a He-Ne laser. The reason why the optimum length of the gold nanorods was 600 nm was discussed by considering the relationship between the absorption peak of surface plasmon resonance and the wavelength of the incident laser for Raman scattering.

  20. Preparation of porous microstructures on NiTi alloy surface with femtosecond laser pulses

    Institute of Scientific and Technical Information of China (English)

    LIANG ChunYong; YANG Yang; WANG HongShui; YANG JianJun; YANG XianJin

    2008-01-01

    Porous microstructures on Nickel-Titanium (NiTi) alloy surfaces were prepared by linearly polarized femtosecond lasers with moving focal point at a certain speed. It was found that various novel micro-structures from feather-like ripples to cluster-like porous textures could be formed with increasing laser energy. Particularly, when the laser energy was 400 μJ, a periodic porous metal surface was gen-erated. Measurement of X-ray diffraction showed that the grains on the sample surface were refined through femtosecond laser ablation processes, but the crystal structures still kept their original states. Analysis by X-ray photoelectron spectroscopy revealed that Ni/Ti on the sample surface was changed with an evident oxidization of titanium element under different laser energies. This investigation pro-vides a new approach to improve the biocompatibility of NiTi-based implant devices.

  1. Preparation of Porous Ceramisite for Waste Water Treatment Made from Red Mud

    Institute of Scientific and Technical Information of China (English)

    XIAO Bo; WU Shenbiao; SHI Xiaoyan; YANG Jiakuan

    2007-01-01

    The porous ceramisites for wastewater treatment were made from red mud, which is the industrial waste discharged from the production ofAl2O3. The sintering process and the degreasing experiments with porous ceramisites have been finished. The results show that the sintering temperature control is dominant for the preparation of the porous ceramisites. The optimal sintering temperature is between 1 110-1 120℃,a narrow range. The surface of ceramists is distributed with a lot of coarse holes with diameters of about 1-10μm. Moreover, the sintering temperatures have a great influence on the efficiency of degreasing, and the curve between the sintering temperature and the efficiency of degreasing is like a parabola.

  2. Facile preparation of hierarchically porous carbons from metal-organic gels and their application in energy storage

    Science.gov (United States)

    Xia, Wei; Qiu, Bin; Xia, Dingguo; Zou, Ruqiang

    2013-06-01

    Porous carbon materials have numerous applications due to their thermal and chemical stability, high surface area and low densities. However, conventional preparing porous carbon through zeolite or silica templates casting has been criticized by the costly and/or toxic procedure. Creating three-dimensional (3D) carbon products is another challenge. Here, we report a facile way to prepare porous carbons from metal-organic gel (MOG) template, an extended metal-organic framework (MOF) structure. We surprisingly found that the carbon products inherit the highly porous nature of MOF and combine with gel's integrated character, which results in hierarchical porous architectures with ultrahigh surface areas and quite large pore volumes. They exhibit considerable hydrogen uptake and excellent electrochemical performance as cathode material for lithium-sulfur battery. This work provides a general method to fast and clean synthesis of porous carbon materials and opens new avenues for the application of metal-organic gel in energy storage.

  3. Synthesis and bioactivity of porous Ti alloy prepared by foaming with TiH{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Y.W., E-mail: ywgu@SIMTech.a-star.edu.sg [Singapore Institute of Manufacturing Technology, 71 Nanyang Drive (Singapore); Yong, M.S.; Tay, B.Y. [Singapore Institute of Manufacturing Technology, 71 Nanyang Drive (Singapore); Lim, C.S. [School of Mechanical and Aerospace Engineering, Nanyang Technological University (Singapore)

    2009-06-01

    A novel porous Ti-6Al-4V with an open cell structure was fabricated by powder metallurgy process with the addition of TiH{sub 2} as the pore forming and active agent. Control of porosity of porous Ti alloy made it possible to obtain the porous Ti with the Young's modulus value of 5.8-9.5 GPa, which was similar to that of human cancellous bone. This kind of porous Ti alloy with good biomechanical properties is potential to alleviate the problem of mechanical mismatch between the bone and the Ti implant. The porous Ti alloy prepared by the addition of TiH{sub 2} as foaming agent had a uniform distribution of pores with pore size of 90-190 {mu}m and porosity of 43-59%. In order to improve the biological properties, the duplex titania/apatite coatings were applied onto the surface of porous Ti alloy. The titania coating was deposited by chemical treatment and the apatite coating was subsequently applied by immersing the samples in a simulated body fluid. Results showed that a homogeneous nanocrystallite titania coating with a thickness of 0.8 {mu}m was formed on the surface of the Ti alloy after chemical treatment. The carbonate-containing apatite coating with a thickness of 1 {mu}m was deposited on the surface of titania coating after immersion in simulated body fluid for 7 days. The nucleation of the carbonate-containing apatite can be induced from the electrostatic interaction between the OH-containing groups on the surface of titania coating and the calcium and phosphate ions in the metastable simulated body fluid on those specific superficial sites. The growth kinetics of the coatings was also discussed. Cell culture test showed the well stretched and proliferated cells on the surface of the sample, indicating the good biocompatibility of porous Ti alloy.

  4. Preparation and Photocatalytic Property of TiO2/Diatomite-Based Porous Ceramics Composite Materials

    Directory of Open Access Journals (Sweden)

    Shuilin Zheng

    2012-01-01

    Full Text Available The diatomite-based porous ceramics was made by low-temperature sintering. Then the nano-TiO2/diatomite-based porous ceramics composite materials were prepared by hydrolysis deposition method with titanium tetrachloride as the precursor of TiO2 and diatomite-based porous as the supporting body of the nano-TiO2. The structure and microscopic appearance of nano-TiO2/diatomite-based porous ceramics composite materials was characterized by XRD and SEM. The photocatalytic property of the composite was investigated by the degradation of malachite green. Results showed that, after calcination at 550°C, TiO2 thin film loaded on the diatomite-based porous ceramics is anatase TiO2 and average grain size of TiO2 is about 10 nm. The degradation ratio of the composite for 5 mg/L malachite green solution reached 86.2% after irradiation for 6 h under ultraviolet.

  5. Highly porous, low elastic modulus 316L stainless steel scaffold prepared by selective laser melting.

    Science.gov (United States)

    Čapek, Jaroslav; Machová, Markéta; Fousová, Michaela; Kubásek, Jiří; Vojtěch, Dalibor; Fojt, Jaroslav; Jablonská, Eva; Lipov, Jan; Ruml, Tomáš

    2016-12-01

    Recently, porous metallic materials have been extensively studied as candidates for use in the fabrication of scaffolds and augmentations to repair trabecular bone defects, e.g. in surroundings of joint replacements. Fabricating these complex structures by using common approaches (e.g., casting and machining) is very challenging. Therefore, rapid prototyping techniques, such as selective laser melting (SLM), have been investigated for these applications. In this study, we characterized a highly porous (87 vol.%) 316L stainless steel scaffold prepared by SLM. 316L steel was chosen because it presents a biomaterial still widely used for fabrication of joint replacements and, from the practical point of view, use of the same material for fabrication of an augmentation and a joint replacement is beneficial for corrosion prevention. The results are compared to the reported properties of two representative nonporous 316L stainless steels prepared either by SLM or casting and subsequent hot forging. The microstructural and mechanical properties and the surface chemical composition and interaction with the cells were investigated. The studied material exhibited mechanical properties that were similar to those of trabecular bone (compressive modulus of elasticity ~0.15GPa, compressive yield strength ~3MPa) and cytocompatibility after one day that was similar to that of wrought 316L stainless steel, which is a commonly used biomaterial. Based on the obtained results, SLM is a suitable method for the fabrication of porous 316L stainless steel scaffolds with highly porous structures.

  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. Progress in the preparation and application of three-dimensional graphene-based porous nanocomposites

    Science.gov (United States)

    Yan, Zhengquan; Yao, Wenli; Hu, Lei; Liu, Dandan; Wang, Chundong; Lee, Chun-Sing

    2015-03-01

    Due to high specific surface area, excellent conductivity, low mass density, good compatibility and elegant flexibility, three-dimensional graphene composites with interconnected porous structures possess unusual and novel physical and electronic properties, unsurpassed chemical functionalities and other attractive features. Therefore, different three-dimensional graphene-based nanoporous scaffolds have been extensively designed, prepared and investigated for practical applications in lithium-ion batteries, super-capacitors, solar cells, catalysis, thermal management, environment pollution enrichment and separation, and chemical sensors with high performance from both fundamental and technological viewpoints. To present readers with a better understanding of this kind of important porous material, in this feature article, we will highlight the main achievements made in the preparation of 3D graphene micro- and/or nano-architectures and their potential applications in the aforementioned fields.

  8. Preparation and characterization of porous carbon–titania nanocomposite films as solar selective absorbers

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, B.; Wang, K.K.; Wang, K.P.; Li, M.; Jiang, W.; Cong, B.J. [State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Song, C.L. [State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Key Laboratory of Advanced Materials and Applications for Batteries of Zhejiang Province (China); Jia, S.H. [Weihai Blue Star Glass Holding Co., Ltd., Weihai 264205 (China); Han, G.R. [State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Key Laboratory of Advanced Materials and Applications for Batteries of Zhejiang Province (China); Liu, Y., E-mail: liuyong.mse@zju.edu.cn [State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Key Laboratory of Advanced Materials and Applications for Batteries of Zhejiang Province (China)

    2015-06-25

    Highlights: • The nanocomposites porous C/TiO{sub 2} film were fabricated via PIPS method. • The HRTEM reveals the size of carbon nanoparticles is about 1.1 nm. • The PVP advantages residual carbon content but suppresses its crystallization. • The film exhibits high α (0.928–0.959) with low ε (0.074–0.105) for single layer. - Abstract: Newly proposed selective solar absorbers of porous carbon–titania nanocomposite films with a well-defined interconnected macropores structure were prepared via a polymer-assisted photopolymerization-induced phase-separation method. The microstructure and optical properties of as-deposited nanocomposite films were characterized and discussed in detail. The results show that non-ionic water-soluble polymer polyvinylpyrrolidone works as a sol modifier advantaging the mean size of the interconnected macropores, residual carbon content, and films thickness, but suppresses the order degree of the carbon remained in the films. The high-resolution transmission electron microscopy demonstrated that a small amount of graphite particles with size of around 1.1 nm embedded in the cavity of the porous while the wall of the porous consists of amorphous carbon and titania composites. The single layer of as-prepared porous C/TiO{sub 2} nanocomposite films exhibits high solar absorptance (α = 0.928–0.959) with low thermal emittance (ε = 0.074–0.105), yielding an optimized photothermal conversion efficiency η = α − ε of 0.864 corresponding to a film thickness of around 338 nm, indication of such film is fair enough to serve as an excellent solar absorber.

  9. Sulfur X-ray absorption fine structure in porous Li–S cathode films measured under argon atmospheric conditions

    Energy Technology Data Exchange (ETDEWEB)

    Müller, Matthias, E-mail: matthias.mueller@ptb.de [Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin (Germany); Choudhury, Soumyadip [Leibniz-Institut für Polymerforschung, Hohe Strasse 6, 01069 Dresden (Germany); Technische Universität Dresden, Physical Chemistry of Polymeric Materials ,01062 Dresden (Germany); Gruber, Katharina [VARTA Micro Innovation GmbH, Stremayrgasse 9, 8010 Graz (Austria); Cruz, Valene B. [Universität Ulm, Institut für Elektrochemie, 89069 Ulm (Germany); Helmholtz-Institut Ulm (HIU), 89069 Ulm (Germany); Fuchsbichler, Bernd [VARTA Micro Innovation GmbH, Stremayrgasse 9, 8010 Graz (Austria); Jacob, Timo [Universität Ulm, Institut für Elektrochemie, 89069 Ulm (Germany); Helmholtz-Institut Ulm (HIU), 89069 Ulm (Germany); Koller, Stefan [VARTA Micro Innovation GmbH, Stremayrgasse 9, 8010 Graz (Austria); Stamm, Manfred [Leibniz-Institut für Polymerforschung, Hohe Strasse 6, 01069 Dresden (Germany); Technische Universität Dresden, Physical Chemistry of Polymeric Materials ,01062 Dresden (Germany); Ionov, Leonid [Leibniz-Institut für Polymerforschung, Hohe Strasse 6, 01069 Dresden (Germany); Beckhoff, Burkhard [Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin (Germany)

    2014-04-01

    In this paper we present the first results for the characterization of highly porous cathode materials with pore sizes below 1 μm for Lithium Sulfur (Li–S) batteries by Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy. A novel cathode material of porous carbon films fabricated with colloidal array templates has been investigated. In addition, an electrochemical characterization has been performed aiming on an improved correlation of physical and chemical parameters with the electrochemical performance. The performed NEXAFS measurements of cathode materials allowed for a chemical speciation of the sulfur content inside the cathode material. The aim of the presented investigation was to evaluate the potential of the NEXAFS technique to characterize sulfur in novel battery material. The long term goal for the characterization of the battery materials is the sensitive identification of undesired side reactions, such as the polysulfide shuttle, which takes place during charging and discharging of the battery. The main drawback associated with the investigation of these materials is the fact that NEXAFS measurements can usually only be performed ex situ due to the limited in situ instrumentation being available. For Li–S batteries this problem is more pronounced because of the low photon energies needed to study the sulfur K absorption edge at 2472 eV. We employed 1 μm thick Si{sub 3}N{sub 4} windows to construct sealed argon cells for NEXAFS measurements under ultra high vacuum (UHV) conditions as a first step towards in situ measurements. The cells keep the sample under argon atmosphere at any time and the X-ray beam passes mainly through vacuum which enables the detection of the low energy X-ray emission of sulfur. Using these argon cells we found indications for the presence of lithium polysulfides in the cathode films whereas the correlations to the offline electrochemical results remain somewhat ambiguous. As a consequence of these findings one

  10. Photocatalytic activity of porous TiO2 films prepared by anodic oxidation

    Institute of Scientific and Technical Information of China (English)

    WANG Wei; TAO Jie; WANG Tao; WANG Ling

    2007-01-01

    Anatase titanium dioxide is an active photocatalyst, however, it is difficult to be immobilized on the substrate.The crystalline TiO2 porous film was prepared directly on the surface of pure titanium by anodic oxidation. The film was then used for photocatalysis via the methyl orange degradation method. The effects of anodization voltage, pH value, TiO2 film area and degradation time on the photocatalyst were investigated respectively by UV-visible spectrum. It was indicated that the TiO2 film prepared by anodic oxidation at 140 V had the best photocatalysis capability and the degradation of methyl orange was accelerated with acid addition.

  11. Preparation, microstructure and degradation performance of biomedical magnesium alloy fine wires

    Directory of Open Access Journals (Sweden)

    Jing Bai

    2014-10-01

    Full Text Available With the development of new biodegradable Mg alloy implant devices, the potential applications of biomedical Mg alloy fine wires are realized and explored gradually. In this study, we prepared three kinds of Mg alloy fine wires containing 4 wt% RE(Gd/Y/Nd and 0.4 wt% Zn with the diameter less than 0.4 μm through casting, hot extruding and multi-pass cold drawing combined with intermediated annealing process. Their microstructures, mechanical and degradation properties were investigated. In comparison with the corresponding as-extruded alloy, the final fine wire has significantly refined grain with an average size of 3–4 μm, and meanwhile shows higher yield strength but lower ductility at room temperature. The degradation tests results and surface morphologies observations indicate that Mg–4Gd–0.4Zn and Mg–4Nd–0.4Zn fine wires have similar good corrosion resistance and the uniform corrosion behavior in SBF solution. By contrast, Mg–4Y–0.4Zn fine wire shows a poor corrosion resistance and the pitting corrosion behavior.

  12. Preparation, microstructure and degradation performance of biomedical magnesium alloy fine wires

    Institute of Scientific and Technical Information of China (English)

    Jing Bai; Zhejun Tang; Lingling Yin; Ye Lu; Yiwei Gan; Feng Xue; Chenglin Chu; Jingli Yan; Kai Yan; Xiaofeng Wan

    2014-01-01

    With the development of new biodegradable Mg alloy implant devices, the potential applications of biomedical Mg alloy fine wires are realized and explored gradually. In this study, we prepared three kinds of Mg alloy fine wires containing 4 wt%RE(Gd/Y/Nd) and 0.4 wt%Zn with the diameter less than 0.4μm through casting, hot extruding and multi-pass cold drawing combined with intermediated annealing process. Their microstructures, mechanical and degradation properties were investigated. In comparison with the corresponding as-extruded alloy, the final fine wire has significantly refined grain with an average size of 3–4μm, and meanwhile shows higher yield strength but lower ductility at room temperature. The degradation tests results and surface morphologies observations indicate that Mg–4Gd–0.4Zn and Mg–4Nd–0.4Zn fine wires have similar good corrosion resistance and the uniform corrosion behavior in SBF solution. By contrast, Mg–4Y–0.4Zn fine wire shows a poor corrosion resistance and the pitting corrosion behavior.

  13. Preparation and characterization of porous titania-grafted poly(styrene-divinylbenzene)/maleic anhydride nanocomposite microspheres

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Mesoporous titania-grafted poly(styrene-divinylbenzene)/maleic anhydride [P(St-DVB)/MA] nanocomposite microspheres were prepared by an open ring reaction method.The titania nanoparticles were first modified by attachment of amino groups to their surface to prevent particle aggregation,and to allow the nanoparticles to covalently bond the polymer microspheres,the surface of which was modified by attachment of MA functional groups to enable the polymer to retain their porous structures and to react with the amino groups on the surface of the titania particles.The porous nanocomposite microspheres were detected by FTIR,SEM,TEM,XRD and UV-Vis spectrophotometry.The results indicated that the nanocomposite microspheres were composed of nanosized titania uniformly distributed on the surface,and exhibited better UV absorbing property than pure polymer microspheres or unmodified titania.Furthermore,compared with pure porous polymer microspheres,the nanocomposite microspheres showed more efficient UV protection and slow release of Parsol-1789(a photo-reactive and cosmetic agent) held inside the porous network of the microspheres.

  14. Preparation and crystalline phase of a TiO2 porous film by anodic oxidation

    Institute of Scientific and Technical Information of China (English)

    WANG Wei; TAO Jie; ZHANG Weiwei; TAO Haijun; WANG Ling

    2005-01-01

    Anatase titanium dioxide is an active photocatalyst, but it is difficult to immobilize on the substrate. A crystalline TiO2 porous film was prepared directly on the surface of pure titanium by anodic oxidation in this work. Constant voltage and constant current anodic oxidation were adopted with sulphuric acid used as the electrolyte, pure titanium as the anode and copper as the cathode. The morphology and structure of the porous film on the substrate were analyzed with the aid of Field Emission Scanning Electron Microscopy (FESEM) and X-ray Diffraction (XRD). The effects of the parameters of anodic oxidation (such as voltage, the concentration of sulphuric acid, anodization time and current density) on the aperture and the crystalline phase of the TiO2 porous film were systematically investigated. The results indicate that the increase of current density facilitates the augment of the aperture and the generation of anatase and rutile. In addition, the forming mechanism of anatase and rutile TiO2 porous films was discussed.

  15. Preparation and Properties of Doped Lanthanum Gallate Film on a Ni/SDC Porous Anode Support

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A 65.8-μm dense doped lanthanum gallate La0.8Sr0.2Ga0.85Mg0.15O2.825 (LSGM)film was prepared on a porous Ni/SDC(samarium doped ceria, Ce0.8Sm0.2O1.9) anode support by colloid suspension deposition with incomplete crystallization LSGM powder as a starting material. The phase composition and micromorphology of the LSGM film were characterized by X-ray diffraction and scanning electron microscopy. The electrical properties of the LSGM film and the performances of the LSGM film solid oxide fuel cell were also analyzed. The results show that both the dense LSGM film on the porous anode support, and the required phase composition of the LSGM film were obtained simultaneously by sintering at 1400℃ for 6 h. The adhesion between the LSGM film and the porous anode support is very strong. The electrical conductivities of the LSGM film on the porous anode support are 0. 113 and 0. 173 S/cm at 800and 850 ℃, respectively. The maximum output power density of the LSGM film cell is 177 mW/cm2 at 700 ℃.

  16. Preparation of semi-solid slurry containing fine and globular particles for wrought aluminum alloy 2024

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The semi-solid slurry of wrought aluminum alloy 2024 was prepared by a well developed rheocasting process, low superheat pouring with shearing field(LSPSF). The appreciate combination of pouring temperature and rotation speed of barrel, can give rise to a transition of the growth morphology of primary α(Al) from coarse-dendritic to coarse-particle-like and further to fine-globular. The combined effects of both localized rapid cooling and vigorous mixing during the initial stage of solidification can enhance wall nucleation and nuclei survival, which leads to the formation of fine-globular primary α(Al). By using semi-solid slurry prepared by LSPSF, direct squeeze cast cup-shaped component with improved mechanical properties such as yield strength of 198MPa, ultimate tensile strength of 306 MPa and elongation of 10.4%, can be obtained.

  17. Preparation and optimization of glyceryl behenate-based highly porous pellets containing cilostazol.

    Science.gov (United States)

    Hwang, Kyu-Mok; Byun, Woojin; Cho, Cheol-Hee; Park, Eun-Seok

    2016-11-03

    The aim of this study was to prepare a highly porous multiparticulate dosage form containing cilostazol for gastroretentive drug delivery. The floating pellets were prepared with glyceryl behenate as a matrix former and camphor as a sublimating agent by extrusion/spheronization and sublimation under vacuum. Granules prepared with sublimation at 60 °C displayed a slower dissolution rate and smoother surface morphology than those prepared at lower temperatures. This was unexpected as the reported melting point of glyceryl behenate is higher than 69 °C. The DSC study revealed that melting began at a lower temperature owing to the multicomponent property of glyceryl behenate, which led to a sintering effect. The prepared pellets were spherical with unimodal size distribution. They also had porous structures with increased porosity, which led to immediate buoyancy. As cilostazol is a hydrophobic drug that has an erosion-based release mechanism, drug release profile was highly correlated with the percentage of disintegrated pellets. Various excipients were added to the glyceryl behenate-based formulation to increase the floating duration. When hydroxyethyl cellulose was added to the glyceryl behenate-based pellets, acceptable dissolution rate and buoyancy were acquired. This system could potentially be used for gastroretentive delivery of various hydrophobic drugs, which was generally considered difficult.

  18. Influence of preparation and storage conditions on photoluminescence of porous silicon powder with embedded Si nanocrystals

    Energy Technology Data Exchange (ETDEWEB)

    Bychto, Leszek, E-mail: leszek.bychto@tu.koszalin.pl; Balaguer, Maria; Pastor, Ester; Chirvony, Vladimir; Matveeva, Eugenia, E-mail: eumat@upvnet.upv.e [Technical University of Valencia, Nanophotonics Technology Center (Spain)

    2008-12-15

    The time changes of photoluminescence (PL) characteristics of porous silicon (porSi) powder during storing in different ambients have been reported. A porous silicon material with embedded Si nanocrystals of size of few nanometers was prepared by an electrochemical method from 10 to 20 {Omega}cm p-type Si wafers, and both constant and pulse current anodization regimes were used. A powder with a submicron average particle size was obtained by simple mechanical lift-off of the porous layer followed by additional manual milling. The air, hexane, and water as storage media were used, and modification by a nonionic surfactant (undecylenic acid) of the porSi surface was applied in the latter case. Dependence of PL characteristics on preparation and storage conditions was then studied. A remarkable blue shift of a position of PL maximum was observed in time for porSi powders in each storage media. In water suspension a many-fold build-up (10-30) of PL intensity in a time scale of few days was accompanied by an observed blue shift. Photoluminescence time behavior of porSi powders was described by a known mechanism of the change of porSi PL from free exciton emission of Si nanocrystals to luminescence of localized oxidized states on the Si nanocrystal surface.

  19. Understanding and Modeling the Liquid Uptake in Porous Compacted Powder Preparations.

    Science.gov (United States)

    Esteban, Jesús; Moxon, Thomas E; Simons, Tom A H; Bakalis, Serafim; Fryer, Peter J

    2017-07-18

    Porous solid materials commonly undergo coating processes during their manufacture, where liquids are put in contact with solids for different purposes. The study of liquid penetration in porous substrates is a process of high relevance in activities in several industries. In particular, powder detergents are subject to coating with surfactants that will boost their performance, although this may affect the flowability and even cause caking of the particulate material, which can be detrimental to consumer acceptance. Here we present a methodology to make compacted preparations of powders relevant to detergent making and evaluate the internal structure of such porous substrates by means of X-ray microcomputed tomography. Liquid penetration in the preparation and the total mass uptake of fluid were monitored by a gravimetric technique based on a modified Wilhelmy plate method consisting of consecutive cycles. Taking into account the geometry of the system, two models were proposed to describe the liquid uptake based on the process being driven by mass (model 1) or pressure (model 2) gradients. A comparison between both from statistical and physical points of view led to the conclusion that the latter was more appropriate for describing the process and retrieving values of the permeability of the solid between 0.03 × 10(-12) and 0.95 × 10(-12) m(2). Finally, with the parameters retrieved from model 2, the force balance observed throughout the experiment was simulated satisfactorily.

  20. On the use of mesophase pitch for the preparation of hierarchical porous carbon monoliths by nanocasting

    Directory of Open Access Journals (Sweden)

    Philipp Adelhelm, Karin Cabrera and Bernd M Smarsly

    2012-01-01

    Full Text Available A detailed study is given on the synthesis of a hierarchical porous carbon, possessing both meso- and macropores, using a mesophase pitch (MP as the carbon precursor. This carbon material is prepared by the nanocasting approach involving the replication of a porous silica monolith (hard templating. While this carbon material has already been tested in energy storage applications, various detailed aspects of its formation and structure are addressed in this study. Scanning electron microscopy (SEM, Hg porosimetry and N2 physisorption are used to characterize the morphology and porosity of the carbon replica. A novel approach for the detailed analysis of wide-angle x-ray scattering (WAXS from non-graphitic carbons is applied to quantitatively compare the graphene microstructures of carbons prepared using MP and furfuryl alcohol (FA. This WAXS analysis underlines the importance of the carbon precursor in the synthesis of templated porous carbon materials via the nanocasting route. Our study demonstrates that a mesophase pitch is a superior precursor whenever a high-purity, low-micropore-content and well-developed graphene structure is desired.

  1. Sonochemical preparation of stable porous MnO2 and its application as an efficient electrocatalyst for oxygen reduction reaction.

    Science.gov (United States)

    Zuo, Ling-Xia; Jiang, Li-Ping; Abdel-Halim, E S; Zhu, Jun-Jie

    2017-03-01

    Porous MnO2 as a non-noble metal oxygen reduction reaction (ORR) electrocatalyst was prepared by a simple sonochemical route. The as-prepared porous MnO2 exhibited higher electrocatalytic activity, superior stability and better methanol tolerance than commercial Pt/C catalyst in alkaline media. Furthermore, the ORR proceeded via a nearly four-electron pathway. Cyclic voltammetry (CV) and rotating-disk electrode (RDE) measurements verified that the ORR enhancement was attributed to the porous structure and good dispersity, which facilitated sufficient transport of ions, electrons, O2 and other reactants in the process of ORR. The results indicated that a facile and feasible sonochemical route could be used to prepare highly active porous MnO2 electrocatalyst for ORR, which might be promising for direct methanol fuel cells.

  2. Porous starch/cellulose nanofibers composite prepared by salt leaching technique for tissue engineering.

    Science.gov (United States)

    Nasri-Nasrabadi, Bijan; Mehrasa, Mohammad; Rafienia, Mohammad; Bonakdar, Shahin; Behzad, Tayebeh; Gavanji, Shahin

    2014-08-08

    Starch/cellulose nanofibers composites with proper porosity pore size, mechanical strength, and biodegradability for cartilage tissue engineering have been reported in this study. The porous thermoplastic starch-based composites were prepared by combining film casting, salt leaching, and freeze drying methods. The diameter of 70% nanofibers was in the range of 40-90 nm. All samples had interconnected porous morphology; however an increase in pore interconnectivity was observed when the sodium chloride ratio was increased in the salt leaching. Scaffolds with the total porogen content of 70 wt% exhibited adequate mechanical properties for cartilage tissue engineering applications. The water uptake ratio of nanocomposites was remarkably enhanced by adding 10% cellulose nanofibers. The scaffolds were partially destroyed due to low in vitro degradation rate after more than 20 weeks. Cultivation of isolated rabbit chondrocytes on the fabricated scaffold proved that the incorporation of nanofibers in starch structure improves cell attachment and proliferation.

  3. Porous polylactic acid-silica hybrids: preparation, characterization, and study of mesenchymal stem cell osteogenic differentiation.

    Science.gov (United States)

    Pandis, Christos; Trujillo, Sara; Matos, Joana; Madeira, Sara; Ródenas-Rochina, Joaquín; Kripotou, Sotiria; Kyritsis, Apostolos; Mano, João F; Gómez Ribelles, José Luis

    2015-02-01

    A novel approach to reinforce polymer porous membranes is presented. In the prepared hybrid materials, the inorganic phase of silica is synthesized in-situ and inside the pores of aminolyzed polylactic acid (PLA) membranes by sol-gel reactions using tetraethylorthosilicate (TEOS) and glycidoxypropyltrimethoxysilane (GPTMS) as precursors. The hybrid materials present a porous structure with a silica layer covering the walls of the pores while GPTMS serves also as coupling agent between the organic and inorganic phase. The adjustment of silica precursors ratio allows the modulation of the thermomechanical properties. Culture of mesenchymal stem cells on these supports in osteogenic medium shows the expression of characteristic osteoblastic markers and the mineralization of the extracellular matrix.

  4. In situ sol-gel preparation of porous alumina monoliths for chromatographic separations of adenosine phosphates.

    Science.gov (United States)

    Zajickova, Zuzana; Rubi, Emir; Svec, Frantisek

    2011-06-03

    A method enabling the in situ preparation of porous alumina monoliths within 100 μm i.d. fused silica capillaries has been developed. These monoliths were prepared using the sol-gel process from a mixture consisting of an inorganic aluminum salt, a porogen, an epoxide, and a solvent. We investigated the effects of varying the preparation conditions on the physical characteristics of the monoliths with respect to their potential application in chromatographic separations. The best columns were obtained from a mixture of aluminum chloride hexahydrate, N,N-dimethylformamide, water, ethanol and propylene oxide. Adenosine phosphates were then separated in the optimized column with retention increasing according to number of phosphate functionalities.

  5. Preparation of microcapsule-supported palladium catalyst using SPG (Shirasu Porous Glass) emulsification technique

    Institute of Scientific and Technical Information of China (English)

    Ying Liu; Xiu Juan Feng; De Cai Bao; Kai Xiao Li; Ming Bao

    2010-01-01

    A new method for the preparation of microcapsule-supported palladium catalyst was described.The highly monodisperse crosslinked polystyrene microcapsules containing phosphine ligand were synthesized by the self-assembling of phase separated polymer(SaPSeP)method using diphenyl(4-vinylphenyl)phosphine and divinylbenzene as a monomer and crosslinking agent,respectively,and 2,2'-azobisisobutyronitrile(AIBN)as an initiator within the droplets of oil-in-water(O/W)emulsions,which were prepared by using the Shirasu Porous Glass(SPG)membrane emulsification technique.The prepared microcapsule-supported palladium catalyst exhibited high catalytic activity for Heck reaction and can be reused several times without loss of activity.

  6. Preparation and Characterization of Carbon Foam Derived from Fine Coal and Phenolic Resin

    Directory of Open Access Journals (Sweden)

    Dodi Irwandi

    2016-12-01

    Full Text Available Carbon foam from fine coal and phenolic resin mixture had been prepared by heating in nitrogen atmosphere. The composition of fine coal in a mixture was 30, 35, 40, 45 and 50%. Physical and mechanical characters of carbon foam that were determined from each of these compositions were density, porosity, compressive strength, and oxidation resistance and thermal insulation. Microstructure was observed by scanning electron microscope (SEM. Thermal insulation was tested using an insulation index approach with Styrofoam for comparison. The result showed that the density and compressive strength were proportional to the composition, otherwise, the porosity. Oxidation resistance that was up to 45% composition still showed proportional value. Microstructure observations showed an irregular distribution of pore and uninform diameter. Insulation index of 34 to 50 °C showed almost the same values of all compositions and greater than styrofoam up to 50-150% which mean carbon foam had a better thermal insulation properties than styrofoam.

  7. Preparation of ferromagnetic metal fine fibers by organic gel-thermal reduction process

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The organic gel-thermal reduction process was used for the preparation of ferromagnetic metal Ni, Co and Fe fine fibers from the raw materials of citric acid, lactic acid and metal salts. The structure, thermal decomposition process and morphologies of the gel precursors and fibers derived from thermal reduction of these gel precursors were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, thermo-gravimetric/differential scanning calorimetry and scanning electron microscopy. The results show that spinnability of gel largely depends on molecular structure of metal-carboxylate complex that is a linear-type structure formed in the gel. As a result, the gels exhibit a good spinnability. Metal Ni, Co and Fe fine fibers are featured with diameters of around 1 urn and a high aspect ratio up to 1×106.

  8. Preparation and guest-uptake protocol for a porous complex useful for 'crystal-free' crystallography.

    Science.gov (United States)

    Inokuma, Yasuhide; Yoshioka, Shota; Ariyoshi, Junko; Arai, Tatsuhiko; Fujita, Makoto

    2014-02-01

    We recently reported a new method for single-crystal X-ray diffraction (SCD) analysis that does not require the crystallization of the target compound. In this 'crystal-free' crystallography, a tiny crystal of a porous complex is soaked in the solution of the target guest. The guest molecules are absorbed and oriented in the crystal pores and can be analyzed by X-ray diffraction. We describe here a detailed synthetic protocol for the preparation of uniform single crystals of the porous host complex and for the subsequent guest uptake. The protocol describes our most versatile porous complex, which is prepared from commercially available ZnI2 and 2,4,6-tri(4-pyridyl)-1,3,5-triazine. The host complex has large pores with a cross-section of 8 × 5 Å(2). Single crystals of the complex are grown from layered solutions of the two components. The pores of the as-synthesized complex are filled with nitrobenzene, which is replaced with the inert solvent cyclohexane. This solvent exchange is essential for the rapid and effective inclusion of target compounds. The most crucial and delicate step is the selection of high-quality single crystals from the mixture of crystals of various shapes and sizes. We suggest using the facial indices of the single crystals as a criterion for crystal selection. Single-crystal samples for X-ray analysis can be prepared by immersing the selected crystals in a cyclohexane/dichloromethane solution of target compound. After a very slow evaporation of the solvent, typically over 2 d, the final crystal can be picked and directly subjected to SCD analysis. The protocol can be completed within ∼16 d.

  9. Preparation of porous carbon sphere from waste sugar solution for electric double-layer capacitor

    Science.gov (United States)

    Hao, Zhi-Qiang; Cao, Jing-Pei; Wu, Yan; Zhao, Xiao-Yan; Zhuang, Qi-Qi; Wang, Xing-Yong; Wei, Xian-Yong

    2017-09-01

    Waste sugar solution (WSS), which contains abundant 2-keto-L-gulonic acid, is harmful to the environment if discharged directly. For value-added utilization of the waste resource, a novel process is developed for preparation of porous carbon spheres by hydrothermal carbonization (HTC) of WSS followed by KOH activation. Additionally, the possible preparation mechanism of carbon spheres is proposed. The effects of hydrothermal and activation parameters on the properties of the carbon sphere are also investigated. The carbon sphere is applied to electric double-layer capacitor and its electrochemical performance is studied. These results show that the carbon sphere obtained by HTC at 180 °C for 12 h with the WSS/deionized water volume ratio of 2/3 possess the highest specific capacitance under identical activation conditions. The specific capacitance of the carbon spheres can reach 296.1 F g-1 at a current density of 40 mA g-1. Besides, excellent cycle life and good capacitance retention (89.6%) are observed at 1.5 A g-1 after 5000 cycles. This study not only provides a facile and potential method for the WSS treatment, but also achieves the high value-added recycling of WSS for the preparation of porous carbon spheres with superior electrochemical properties.

  10. Bismuth Modified Porous Silica Preparation, Characterization and Photocatalytic Activity Evaluation for Degradation of Isoproturon

    Institute of Scientific and Technical Information of China (English)

    Anil Kumar Reddy Police; Srinivas Basavaraju; Durga Kumari Valluri; Subrahmanyam Machiraju

    2013-01-01

    Porous silica prepared by using an acrylic emulsion has been impregnated with bismuth ion resulting in Bi2Sio5 species containing surface.The as-prepared materials have been characterized by X-ray diffraction spectroscopy (XRD),X-ray photoelectron spectroscopy (XPS),UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS),scanning electron microscopy (SEM),energy dispersive analysis of X-ray (EDAX),transmission electron microscopy (TEM),Fourier transform infrared spectroscopy (FTIR) and N2 adsorption/desorption techniques.EDAX analysis confirms the penetration of bismuth ions into the framework of silica to form Bi2Sio5,which is substantiated by XRD.The UV-Vis DRS shows that the catalysts are optically active and XPS confirms the inclusion of bismuth into the framework of silica.FTIR spectra illustrate the formation of Bi-O-Si linkages in the porous silica framework.SEM and TEM show the spherical morphology,whereas N2 adsorption/desorption study confirms the porosity of the prepared materials.The photocatalytic activity of the material is evaluated for the degradation of isoproturon herbicide and it is found that the material is active as compared to the commercial P-25 Degussa Tio2.

  11. Templated preparation of porous magnetic microspheres and their application in removal of cationic dyes from wastewater.

    Science.gov (United States)

    Liu, Qingquan; Wang, Li; Xiao, Anguo; Gao, Jingming; Ding, Wenbing; Yu, Haojie; Huo, Jia; Ericson, Mårten

    2010-09-15

    Porous magnetic microspheres with large particle size (350-450 microm) were prepared with sulfonated macroporous polydivinylbenzene as a template. The preparation process included ferrous ion exchange and following oxidation by hydrogen peroxide. The results showed that the weight fraction of magnetic nanoparticles exceeded 20 wt% in microspheres after the preparation process was repeated three times. X-ray diffraction profiles indicated that the crystalline phase of as-formed magnetic nanoparticles was magnetite (Fe(3)O(4)). TEM images revealed rod-like magnetite crystal after the first oxidation cycle, however, the crystal morphologies were transferred into random shape after more oxidation cycles. The applicability of porous magnetic microspheres for removal of cationic dyes from water was also explored. The results exhibited that basic fuchsin and methyl violet could be quickly removed from water with high efficiency. More importantly, the magnetic microspheres could be easily regenerated and repeatedly employed for wastewater treatment. Therefore, a novel methodology was provided for fast removal cationic dyes from wastewater. Copyright 2010 Elsevier B.V. All rights reserved.

  12. Preparation of hierarchical porous Zn-salt particles and their superhydrophobic performance

    Science.gov (United States)

    Gao, Dahai; Jia, Mengqiu

    2015-12-01

    Superhydrophobic surfaces arranged by hierarchical porous particles were prepared using modified hydrothermal routes under the effect of sodium citrate. Two particle samples were generated in the medium of hexamethylenetetramine (P1) and urea (P2), respectively. X-ray diffraction, scanning electron microscope, and transmission electron microscope were adopted for the investigation, and results revealed that the P1 and P2 particles are porous microspheres with crosslinked extremely thin (10-30 nm) sheet crystals composed of Zn5(OH)8Ac2·2H2O and Zn5(CO3)2(OH)6, respectively. The prepared particles were treated with a fluoroethylene vinyl ether derivative and studied using Fourier transform infrared spectroscopy and energy-dispersive X-ray spectrometer. Results showed that the hierarchical surfaces of these particles were combined with low-wettable fluorocarbon layers. Moreover, the fabricated surface composed of the prepared hierarchical particles displayed considerably high contact angles, indicating great superhydrophobicity for the products. The wetting behavior of the particles was analyzed with a theoretical wetting model in comparison with that of chestnut-like ZnO products obtained through a conventional hydrothermal route. Correspondingly, this study provided evidence that high roughness surface plays a great role in superhydrophobic behavior.

  13. Preparation of porous carbon nanofibers derived from PBI/PLLA for supercapacitor electrodes

    Science.gov (United States)

    Jung, Kyung-Hye; Ferraris, John P.

    2016-10-01

    Porous carbon nanofibers were prepared by electrospinning blend solutions of polybenzimidazole/poly-L-lactic acid (PBI/PLLA) and carbonization. During thermal treatment, PLLA was decomposed, resulting in the creation of pores in the carbon nanofibers. From SEM images, it is shown that carbon nanofibers had diameters in the range of 100-200 nm. The conversion of PBI to carbon was confirmed by Raman spectroscopy, and the surface area and pore volume of carbon nanofibers were determined using nitrogen adsorption/desorption analyses. To investigate electrochemical performances, coin-type cells were assembled using free-standing carbon nanofiber electrodes and ionic liquid electrolyte. cyclic voltammetry studies show that the PBI/PLLA-derived porous carbon nanofiber electrodes have higher capacitance due to lower electrochemical impedance compared to carbon nanofiber electrode from PBI only. These porous carbon nanofibers were activated using ammonia for further porosity improvement and annealed to remove the surface functional groups to better match the polarity of electrode and electrolyte. Ragone plots, correlating energy density with power density calculated from galvanostatic charge-discharge curves, reveal that activation/annealing further improves energy and power densities.

  14. Preparation of porous carbon nanofibers derived from PBI/PLLA for supercapacitor electrodes.

    Science.gov (United States)

    Jung, Kyung-Hye; Ferraris, John P

    2016-10-21

    Porous carbon nanofibers were prepared by electrospinning blend solutions of polybenzimidazole/poly-L-lactic acid (PBI/PLLA) and carbonization. During thermal treatment, PLLA was decomposed, resulting in the creation of pores in the carbon nanofibers. From SEM images, it is shown that carbon nanofibers had diameters in the range of 100-200 nm. The conversion of PBI to carbon was confirmed by Raman spectroscopy, and the surface area and pore volume of carbon nanofibers were determined using nitrogen adsorption/desorption analyses. To investigate electrochemical performances, coin-type cells were assembled using free-standing carbon nanofiber electrodes and ionic liquid electrolyte. cyclic voltammetry studies show that the PBI/PLLA-derived porous carbon nanofiber electrodes have higher capacitance due to lower electrochemical impedance compared to carbon nanofiber electrode from PBI only. These porous carbon nanofibers were activated using ammonia for further porosity improvement and annealed to remove the surface functional groups to better match the polarity of electrode and electrolyte. Ragone plots, correlating energy density with power density calculated from galvanostatic charge-discharge curves, reveal that activation/annealing further improves energy and power densities.

  15. Preparation and characterization of porous TiO2/ZnO composite nanofibers via electrospinning

    Institute of Scientific and Technical Information of China (English)

    Hai Ying Wang; Yang Yang; Xiang Li; Li Juan Li; Ce Wang

    2010-01-01

    Porous TiO2/ZnO composite nanofibers have been successfully prepared by electrospinning technique for the first time.It was generated by calcining TiO2/ZnCl2/PVP[PVP:poly(vinyi pyrrolidone)]nanofibers,which were electrospun from a mixture solution of TiO2,ZnCl2 and PVE Transmission electron microscopy(TEM)and X-ray diffraction(XRD)analyses were used to identify the morphology of the TiO2/ZnO nanofibers and a formation of inorganic TiO2/ZnO fibers.The porous structure of the TiO2/ZnO fbers was characterized by N2 adsoption/desorption isotherm.Surface photovoltage spectroscopy(SPS)and photo-catalytic activity measurements revealed advance properties of the porous TiO2/ZnO composite nanofibers and the results were compared with pure TiO2 nanofibers,pure ZnO nanofibers and TiO2/ZnO nanoparticles.

  16. Potassium vapor assisted preparation of highly graphitized hierarchical porous carbon for high rate performance supercapacitors

    Science.gov (United States)

    Liu, Zheng; Zeng, Ying; Tang, Qunli; Hu, Aiping; Xiao, Kuikui; Zhang, Shiying; Deng, Weina; Fan, Binbin; Zhu, Yanfei; Chen, Xiaohua

    2017-09-01

    Ultrahigh graphitized carbon microspheres with rich hierarchical pores (AGHPCM-1) have been successfully synthesized through the one-step activation-carbonization strategy (OACS) with porous sulfonated poly-divinylbenzene as the carbon precursor, iron as the hard template and catalyst, and potassium hydroxide (KOH) as activation agent. Through the XRD, TEM, Raman and BET analysis, AGHPCM-1 shows very high graphitization degree and rich micro-, meso- and macro-pores. More importantly, the mechanism for KOH to improve the graphitization degree of carbon materials in OACS has been illustrated by the thermodynamical theory. The tremendous heat releasing from the reaction between the catalyst precursor of Fe2O3 and potassium vapor plays a key role in the formation of graphitized carbon. It may provide a general direction to prepare highly graphitized porous carbon at a moderate temperature. Integrating the advantages of high graphitization degree and rich hierarchical porous structure, the AGHPCM-1 exhibits an excellent rate performance with a response to up to the high current density of 150 A g-1 and high scan rate of 2000 mV s-1. No obvious capacitance decay can be observed after 10000 charge/discharge cycles even at the high current density of 20 A g-1.

  17. Preparation and li storage properties of hierarchical porous carbon fibers derived from alginic acid.

    Science.gov (United States)

    Wu, Xing-Long; Chen, Li-Li; Xin, Sen; Yin, Ya-Xia; Guo, Yu-Guo; Kong, Qing-Shan; Xia, Yan-Zhi

    2010-06-21

    One-dimensional (1D) hierarchical porous carbon fibers (HPCFs) have been prepared by controlled carbonization of alginic acid fibers and investigated with scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, nitrogen adsorption-desorption isotherms, and electrochemical tests toward lithium storage. The as-obtained HPCFs consist of a 3D network of nanosized carbon particles with diameters less than 10 nm and exhibit a hierarchical porous architecture composed of both micropores and mesopores. Electrochemical measurements show that HPCFs exhibit excellent rate capability and capacity retention compared with commercial graphite when employed as anode materials for lithium-ion batteries. At the discharge/charge rate of 45 C, the reversible capacity of HPCFs is still as high as 80 mA h g(-1) even after 1500 cycles, which is about five times larger than that of commercial graphite anode. The much improved electrochemical performances could be attributed to the nanosized building blocks, the hierarchical porous structure, and the 1D morphology of HPCFs.

  18. Silicate-entrapped porous coatings for preparing high-efficiency solid-phase microextraction sorbents

    Energy Technology Data Exchange (ETDEWEB)

    Breton, Francois; Monton, Maria Rowena N. [University of Waterloo, Department of Chemistry, 200 University Ave. West, Waterloo, Ontario N2L 3G1 (Canada); Mullett, Wayne M. [MDS Nordion, 447 Marsh Road, Ottawa, Ontario K2K 1X8 (Canada); Pawliszyn, Janusz, E-mail: janusz@uwaterloo.ca [University of Waterloo, Department of Chemistry, 200 University Ave. West, Waterloo, Ontario N2L 3G1 (Canada)

    2010-06-11

    We present a novel way to prepare SPME fibers using a silicate entrapment of porous particles, followed by derivatization using classical organosilane chemistry. The fibers provide a good platform for on-fiber derivatization of desired extraction phases while providing porosity necessary for high extractions capacities. The porous network was created using potassium silicate and porous silica particles. Fibers derivatized using n-butyl, n-octyl, n-octadecyl and n-triacontyl groups were shown to extract benzodiazepines successfully. The coatings were determined to have an average thickness of ca. 8 {mu}m, as determined by a scanning electron microscope, permitting equilibrium times as fast as 2 min. The fibers also showed very good ruggedness towards a vast range of solvents and prolonged use. It was determined that greater extraction efficiencies could be obtained using triacontyl as an extraction phase. The C18 and C30 fibers were also found to provide good linearity (>0.99) for the model analytes over two orders of magnitude, with limits of detection in the sub ng mL{sup -1} levels. C30 fibers were used to establish a correlation between structurally diverse {beta}-blockers and their literature reported Log P values. The C30 fibers provided a good correlation (R{sup 2} = 0.9255) between {beta}-blockers ranging in hydrophobicity from Log P{sub literature} 0.16-4.15 and their respective experimentally determined Log K{sub spme} values.

  19. Preparation of Porous ZrO2 and Study on Its Properties

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The porous zirconia powder with a high surface area was synthesized by means of the ion exchange method from surfactant CTMAB. The highest surface area of the resulted zirconia reached 340 m2/g having been calcined at 500 ℃ for 2 h. The influence of preparing conditions on the surface area was investigated. The results show that the amount of the surfactant and the aging time were two main factors affecting the surface area of zirconia. The IR analysis indicated that the large surface area was related to the cations of the surfactant which incorporated into hydrous zirconia by ion exchange.

  20. An easy method for the preparation of anion exchange membranes: Graft-polymerization of ionic liquids in porous supports

    NARCIS (Netherlands)

    Merle, Geraldine; Chairuna, Annisa; Ven, van de Erik; Nijmeijer, Kitty

    2013-01-01

    A novel way for anion exchange membrane (AEM) preparation has been investigated, avoiding the use of expensive and toxic chemicals. This new synthetic approach to prepare AEMs was based on the use of a porous polybenzylimidazole membrane as support in which functionalized ILs were introduced and sub

  1. Highly porous activated carbons prepared from carbon rich Mongolian anthracite by direct NaOH activation

    Energy Technology Data Exchange (ETDEWEB)

    Byamba-Ochir, Narandalai [School of Chemical Engineering, Chonnam National University, 77 Yongbong-Ro, Gwangju 61186 (Korea, Republic of); Shim, Wang Geun [Department of Polymer Science and Engineering, Sunchon National University, 255 Jungang-Ro, Suncheon, Jeollanam-Do 57922 (Korea, Republic of); Balathanigaimani, M.S., E-mail: msbala@rgipt.ac.in [Department of Chemical Engineering, Rajiv Gandhi Institute of Petroleum Technology, Ratapur Chowk, Rae Bareli, 229316 Uttar Pradesh (India); Moon, Hee, E-mail: hmoon@jnu.ac.kr [School of Chemical Engineering, Chonnam National University, 77 Yongbong-Ro, Gwangju 61186 (Korea, Republic of)

    2016-08-30

    Highlights: • Highly porous carbon materials from Mongolian anthracite by chemical activation. • Cheaper and eco-friendly activation process has been employed. • Activated carbons with graphitic structure and energetically heterogeneous surface. • Surface hydrophobicity and porosity of the activated carbons can be controlled. - Abstract: Highly porous activated carbons (ACs) were prepared from Mongolian raw anthracite (MRA) using sodium hydroxide as an activation agent by varying the mass ratio (powdered MRA/NaOH) as well as the mixing method of chemical agent and powdered MRA. The specific BET surface area and total pore volume of the prepared MRA-based activated carbons (MACs) are in the range of 816–2063 m{sup 2}/g and of 0.55–1.61 cm{sup 3}/g, respectively. The pore size distribution of MACs show that most of the pores are in the range from large micropores to small mesopores and their distribution can be controlled by the mass ratio and mixing method of the activating agent. As expected from the intrinsic property of the MRA, the highly graphitic surface morphology of prepared carbons was confirmed from Raman spectra and transmission electron microscopy (TEM) studies. Furthermore the FTIR and XPS results reveal that the preparation of MACs with hydrophobic in nature is highly possible by controlling the mixing conditions of activating agent and powdered MRA. Based on all the results, it is suggested that the prepared MACs could be used for many specific applications, requiring high surface area, optimal pore size distribution, proper surface hydrophobicity as well as strong physical strength.

  2. Porous Spherical Cellulose Composites Coated by Aluminum (Ⅲ) Oxide and Silicone: Preparation,Characterization and Adsorption Behavior

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Porous spherical cellulose composite (PSCA) coated by aluminum (Ⅲ) oxide was prepared andmodified by organosilicone. SEM images of the surface morphology of the bead cellulose shows that it hasspherical shape and abundant porous structure on its surface. The mapping images of aluminum and silicon ofthe composite (PSCAS) present aluminum( Ⅲ ) oxide and silicone are uniformly dispersed on the surface. Theadsorption behavior of PSCAS toward metal ions was determined.

  3. Energy-Saving Vibration Impulse Coal Degradation at Finely Dispersed Coal-Water Slurry Preparation

    Directory of Open Access Journals (Sweden)

    Moiseev V.A.

    2015-01-01

    Full Text Available Theoretical and experimental research results of processes of finely dispersed coal-water slurry preparation for further generation of energetic gas in direct flow and vortex gas generator plants have been presented. It has been stated that frequency parameters of parabolic vibration impulse mill influence degradation degree. Pressure influence on coal parameters in grinding cavity has been proven. Experimental researches have proven efficiency of vibration impulse mill with unbalanced mass vibrator generator development. Conditions of development on intergranular walls of coal cracks have been defined.

  4. 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.

  5. Preparation of Porous Scaffolds from Silk Fibroin Extracted from the Silk Gland of Bombyx mori (B. mori

    Directory of Open Access Journals (Sweden)

    Liangjun Zhu

    2012-06-01

    Full Text Available In order to use a simple and ecofriendly method to prepare porous silk scaffolds, aqueous silk fibroin solution (ASF was extracted from silk gland of 7-day-old fifth instar larvae of Bombyx mori (B. mori. SDS-page analysis indicated that the obtained fibroin had a molecular weight higher than 200 kDa. The fabrication of porous scaffolds from ASF was achieved by using the freeze-drying method. The pore of porous scaffolds is homogenous and tends to become smaller with an increase in the concentration of ASF. Conversely, the porosity is decreased. The porous scaffolds show impressive compressive strength which can be as high as 6.9 ± 0.4 MPa. Furthermore, ASF has high cell adhesion and growth activity. It also exhibits high ALP activity. This implies that porous scaffolds prepared from ASF have biocompatibility. Therefore, the porous scaffolds prepared in this study have potential application in tissue engineering due to the impressive compressive strength and biocompatibility.

  6. Preparation and cellular response of porous A-type carbonated hydroxyapatite nanoceramics

    Energy Technology Data Exchange (ETDEWEB)

    Li Bo, E-mail: Leewave@126.com [Institute of Biomaterials and Living Cell Imaging Technology, School of Metallurgy and Materials Engineering, Chongqing University of Science and Technology, Chongqing 401331 (China) and National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064 (China); Liao Xiaoling [Institute of Biomaterials and Living Cell Imaging Technology, School of Metallurgy and Materials Engineering, Chongqing University of Science and Technology, Chongqing 401331 (China); Zheng Li [National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064 (China); He Huawei [Department of Prosthodontics, Beijing Stomatological Hospital, Capital Medical University, Beijing, 100050 (China); Wang Hong [National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064 (China); Fan Hongsong, E-mail: hsfan68@hotmail.com [National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064 (China); Zhang Xingdong [National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064 (China)

    2012-05-01

    Microwave sintering using the activated carbon as embedding material was applied in preparation of porous A-type carbonated hydroxyapatite ceramics with nano(nCHA) and submicron (mCHA) structure. By examining the linear shrinkages and the compressive strengths of samples at different temperatures, a suitable microwave sintering temperature was achieved. The microwave sintering method was successfully used to prepare A-type CHA with nano or submicron structure, and the mechanism of the formation of A-type carbonate groups was discussed also. Compared with the samples prepared by the conventional sintering method (mHA), the nCHA bioceramics synthesized by the microwave sintering approach had smaller grain size and more uniform microstructure, and showed a compressive strength similar to the conventional samples. In vitro dissolution test proved that nCHA exhibits better degradation property in comparison to pure HA. Rat osteoblasts were cultured with nCHA, mCHA and mHA to evaluate their biocompatibility, and nCHA showed significant enhancement of cells in attachment, proliferation and differentiation. In conclusion, carbonate groups can be easily introduced to HA crystal structure using the activated carbon as embedding material, and microwave sintering is an effective and simple method in preparing A-type CHA with a nanostructure. Results from this in vitro biological study suggest that porous A-type carbonated hydroxyapatite nanoceramics may be a much better candidate for clinical use in terms of bioactivity. - Highlights: Black-Right-Pointing-Pointer We prepared porous A-type carbonated hydroxyapatite nanoceramics with microwave sintering. Black-Right-Pointing-Pointer We examined physico-chemical characterization and osteoblast response. Black-Right-Pointing-Pointer The nanoceramics have a comparable compressive strength to samples with conventional sintering method. Black-Right-Pointing-Pointer The nanoceramics enhance degradation property, osteoblast

  7. Design and Preparation of Bone Tissue Engineering Scaffolds with Porous Controllable Structure

    Institute of Scientific and Technical Information of China (English)

    LIN Liulan; ZHANG Huicun; ZHAO Li; HU Qingxi; FANG Minglun

    2009-01-01

    A novel method of designing and preparing bone tissue engineering scaffolds with controllable porous structure of both macro channels and micro pores was proposed. The CAD soft-ware UG NX3.0 was used to design the macro channels' shape, size and distribution. By integrating rapid prototyping and traditional porogen technique, the macro channels and micro pores were formed respectively. The size, shape and quantity of micro pores were controlled by porogen particulates. The sintered β-TCP porous scaffolds possessed connective macro channels of approximately 500 μm and micro pores of 200-400 μm. The porosity and connectivity of micro pores became higher with the in-crease of porogen ratio, while the mechanical properties weakened. The average porosity and com-pressive strength of β-TCP scaffolds prepared with porogen ratio of 60wt% were 78.12% and 0.2983 Mpa,respectively. The cells' adhesion ratio of scaffolds was 67.43%. The ALP activity, OCN content and cells micro morphology indicated that cells grew and proliferated well on the scaffolds.

  8. Preparation and Evaluation of Gelatin-Chitosan-Nanobioglass 3D Porous Scaffold for Bone Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Kanchan Maji

    2016-01-01

    Full Text Available The aim of the present study was to prepare and characterize bioglass-natural biopolymer based composite scaffold and evaluate its bone regeneration ability. Bioactive glass nanoparticles (58S in the size range of 20–30 nm were synthesized using sol-gel method. Porous scaffolds with varying bioglass composition from 10 to 30 wt% in chitosan, gelatin matrix were fabricated using the method of freeze drying of its slurry at 40 wt% solids loading. Samples were cross-linked with glutaraldehyde to obtain interconnected porous 3D microstructure with improved mechanical strength. The prepared scaffolds exhibited >80% porosity with a mean pore size range between 100 and 300 microns. Scaffold containing 30 wt% bioglass (GCB 30 showed a maximum compressive strength of 2.2±0.1 MPa. Swelling and degradation studies showed that the scaffold had excellent properties of hydrophilicity and biodegradability. GCB 30 scaffold was shown to be noncytotoxic and supported mesenchymal stem cell attachment, proliferation, and differentiation as indicated by MTT assay and RUNX-2 expression. Higher cellular activity was observed in GCB 30 scaffold as compared to GCB 0 scaffold suggesting the fact that 58S bioglass nanoparticles addition into the scaffold promoted better cell adhesion, proliferation, and differentiation. Thus, the study showed that the developed composite scaffolds are potential candidates for regenerating damaged bone tissue.

  9. Vinyl Ester Oligomer Crosslinked Porous Polymers Prepared via Surfactant-Free High Internal Phase Emulsions

    Directory of Open Access Journals (Sweden)

    Yun Zhu

    2012-01-01

    Full Text Available Using vinyl ester resin (VER containing styrene (or methyl methacrylate and vinyl ester oligomer (VEO as external phase, Pickering high internal phase emulsions (Pickering HIPEs having internal phase volume fraction of up to 95 vol% were prepared with copolymer particles as sole stabilizer. Polymerizing the external phase of these Pickering HIPEs led to porous polymers (poly-Pickering-HIPEs. Compared to the polystyrene- (PS- based poly-Pickering-HIPEs which were prepared with mixture of styrene and divinylbenzene (DVB as crosslinker, the poly-Pickering-HIPEs herein showed much higher elastic modulus and toughness. The elastic modulus of these poly-Pickering-HIPEs increased with increasing the VEO concentration in the external phase, while it decreased with increasing internal phase volume fraction. Increasing VEO concentration in the external phase also resulted in a decrease in the average void diameter as well as a narrow void diameter distribution of the resulting poly-Pickering-HIPEs. In addition, there were many small pores in the voids surface caused by the volume contraction of VER during the polymerization, which suggests a new method to fabricate porous polymers having a well-defined hierarchical pore structure.

  10. Preparation and characterization of hierarchical porous carbons derived from solid leather waste for supercapacitor applications.

    Science.gov (United States)

    Konikkara, Niketha; Kennedy, L John; Vijaya, J Judith

    2016-11-15

    Utilization of crust leather waste (CLW) as precursors for the preparation of hierarchical porous carbons (HPC) were investigated. HPCs were prepared from CLW by pre-carbonization followed by chemical activation using KOH at relatively high temperatures. Textural properties of HPC's showed an extent of micro-and mesoporosity with maximum BET surface area of 716m(2)/g. Inducements of graphitic planes in leather waste derived carbons were observed from X-ray diffraction and HR-TEM analysis. Microstructure, thermal behavior and surface functional groups were identified using FT-Raman, thermo gravimetric analysis and FT-IR techniques. HPCs were evaluated for electrochemical properties by cyclic voltammetry (CV), galvanostatic charge/discharge (GCD) and electrochemical impedance spectroscopy (EIS) by three electrode system. CLC9 sample showed a maximum capacitance of 1960F/g in 1M KCl electrolyte. Results achieved from rectangular curves of CV, GCD symmetric curves and Nyquist plots show that the leather waste carbon is suitable to fabricate supercapacitors as it possess high specific capacitance and electrochemical cycle stability. The present study proposes an effective method for solid waste management in leather industry by the way of converting toxic leather waste to new graphitic porous carbonaceous materials as a potential candidate for energy storage devices.

  11. Electrochemical impedance spectroscopy analysis of porous silicon prepared by photo-electrochemical etching: current density effect

    Science.gov (United States)

    Husairi, F. S.; Rouhi, J.; Eswar, K. A.; Zainurul, A. Z.; Rusop, M.; Abdullah, S.

    2014-09-01

    Electrical impedance characteristics of porous silicon nanostructures (PSiNs) in frequency function were studied. PSiNs were prepared through photo-electrochemical etching method at various current densities (15-40 mA/cm2) and constant etching time. The atomic force microscope images of PSiNs show that pore diameter and roughness increase when current density increases to 35 mA/cm2. The surface roughness subsequently decreases because of continuous etching of pillars, and a second etching process occurs. Photoluminescence spectra show blue and red shift with increasing applied current density that is attributed to PSiNs size. Variations of electrical resistance and capacitance values of PSiNs were measured using electrochemical impedance spectroscopy analysis. These results indicate that PSiNs prepared at 20 mA/cm2 current density have uniform porous structures with a large number of pillars. Furthermore, this PSiNs structure influences large values of charge transfer resistance and double layer capacitance, indicating potential application in sensors.

  12. Nanoparticles prepared from porous silicon nanowires for bio-imaging and sonodynamic therapy.

    Science.gov (United States)

    Osminkina, Liubov A; Sivakov, Vladimir A; Mysov, Grigory A; Georgobiani, Veronika A; Natashina, Ulyana А; Talkenberg, Florian; Solovyev, Valery V; Kudryavtsev, Andrew A; Timoshenko, Victor Yu

    2014-01-01

    Evaluation of cytotoxicity, photoluminescence, bio-imaging, and sonosensitizing properties of silicon nanoparticles (SiNPs) prepared by ultrasound grinding of porous silicon nanowires (SiNWs) have been investigated. SiNWs were formed by metal (silver)-assisted wet chemical etching of heavily boron-doped (100)-oriented single crystalline silicon wafers. The prepared SiNWs and aqueous suspensions of SiNPs exhibit efficient room temperature photoluminescence (PL) in the spectral region of 600 to 1,000 nm that is explained by the radiative recombination of excitons confined in small silicon nanocrystals, from which SiNWs and SiNPs consist of. On the one hand, in vitro studies have demonstrated low cytotoxicity of SiNPs and possibilities of their bio-imaging applications. On the other hand, it has been found that SiNPs can act as efficient sensitizers of ultrasound-induced suppression of the viability of Hep-2 cancer cells.

  13. Preparation and permeability of ZSM-35 zeolite membranes on porous stainless steel tubes

    Institute of Scientific and Technical Information of China (English)

    ZHU Gang; WANG Jinqu; ZHANG Yan; LU Jinming; XIU Jinghai

    2007-01-01

    ZSM-35 zeolite membranes were prepared on porous stainless steel tubes with silica sol and tetraethoxysilane as silica source,and with 1-butylamine and ethylenediamine as templates,respectively.The characterization of X-ray diffraction(XRD)and scanning electron microscopy (SEM)showed that the membranes prepared with ethylene-diamine as the template displayed growth orientation with their crystal planes(h00)parallel to the support surface.The single-component permeability tests of H2,N2 and C3H8 showed that me membranes synthesized with ethylene-diamine as the template,compared with those witb 1-butylamine as the template,showed relatively higher permeation rates and ideal separation factors,and above their corresponding ideal Knudsen diflusion factors,Which might be attributed to the different growth orientation of zeolite membranes synthesized with different templates.

  14. Preparation of hierarchical porous Zn-salt particles and their superhydrophobic performance

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Dahai; Jia, Mengqiu, E-mail: jiamq@mail.buct.edu.cn

    2015-12-30

    Graphical abstract: - Highlights: • Hierarchical particles with high roughness were prepared by modified hydrothermal route. • The high roughness is provided by extremely low thickness of sheet crystals. • FEVE polymer derivative was used for surface treatment of hierarchical surface. • The novel particles via surface treatment were firstly used as superhydrophobic materials. • The product properties were compared with multi-scale ZnO particles via conventional route. - Abstract: Superhydrophobic surfaces arranged by hierarchical porous particles were prepared using modified hydrothermal routes under the effect of sodium citrate. Two particle samples were generated in the medium of hexamethylenetetramine (P1) and urea (P2), respectively. X-ray diffraction, scanning electron microscope, and transmission electron microscope were adopted for the investigation, and results revealed that the P1 and P2 particles are porous microspheres with crosslinked extremely thin (10–30 nm) sheet crystals composed of Zn{sub 5}(OH){sub 8}Ac{sub 2}·2H{sub 2}O and Zn{sub 5}(CO{sub 3}){sub 2}(OH){sub 6}, respectively. The prepared particles were treated with a fluoroethylene vinyl ether derivative and studied using Fourier transform infrared spectroscopy and energy-dispersive X-ray spectrometer. Results showed that the hierarchical surfaces of these particles were combined with low-wettable fluorocarbon layers. Moreover, the fabricated surface composed of the prepared hierarchical particles displayed considerably high contact angles, indicating great superhydrophobicity for the products. The wetting behavior of the particles was analyzed with a theoretical wetting model in comparison with that of chestnut-like ZnO products obtained through a conventional hydrothermal route. Correspondingly, this study provided evidence that high roughness surface plays a great role in superhydrophobic behavior.

  15. Highly porous activated carbons prepared from carbon rich Mongolian anthracite by direct NaOH activation

    Science.gov (United States)

    Byamba-Ochir, Narandalai; Shim, Wang Geun; Balathanigaimani, M. S.; Moon, Hee

    2016-08-01

    Highly porous activated carbons (ACs) were prepared from Mongolian raw anthracite (MRA) using sodium hydroxide as an activation agent by varying the mass ratio (powdered MRA/NaOH) as well as the mixing method of chemical agent and powdered MRA. The specific BET surface area and total pore volume of the prepared MRA-based activated carbons (MACs) are in the range of 816-2063 m2/g and of 0.55-1.61 cm3/g, respectively. The pore size distribution of MACs show that most of the pores are in the range from large micropores to small mesopores and their distribution can be controlled by the mass ratio and mixing method of the activating agent. As expected from the intrinsic property of the MRA, the highly graphitic surface morphology of prepared carbons was confirmed from Raman spectra and transmission electron microscopy (TEM) studies. Furthermore the FTIR and XPS results reveal that the preparation of MACs with hydrophobic in nature is highly possible by controlling the mixing conditions of activating agent and powdered MRA. Based on all the results, it is suggested that the prepared MACs could be used for many specific applications, requiring high surface area, optimal pore size distribution, proper surface hydrophobicity as well as strong physical strength.

  16. Preparation of fine copper powders and their application in BME-MLCC

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The preparation of fine copper powders by chemical reduction method was investigated. The reaction of [Cu(NH3)4] 2+complex with hydrazine hydrate gives spherical monodispersed fine copper powders. The spherical copper powder with a uniform size of 3.5 ± 0.5 μm was processed to obtain flake copper powder having a uniform size of 8-10 μm, excellent dispersibility and uniform shape. The spherical copper powder of 2.5 ± 0.3 μm in size, flake copper, glass frit and vehicle were mixed to prepare copper paste,which was fired in 910-920℃ to obtain BME-MLCC (base metal multilayer ceramic capacitor) with a dense surface of end termination,high adhesion and qualified electrical behavior. Polarized light photo and SEM were employed to observe the copper end termination of BME-MLCC. The rough interface from the interfacial reaction between glass and chip gives high adhesion.

  17. Light-Driven Preparation, Microstructure, and Visible-Light Photocatalytic Property of Porous Carbon-Doped TiO2

    Directory of Open Access Journals (Sweden)

    Xiao-Xin Zou

    2012-01-01

    Full Text Available Highly porous carbon-doped TiO2 (C-TiO2 has been prepared, for the first time, through a light-driven approach using crystalline titanium glycolate (TG as the single-source precursor. Although the nonthermally prepared porous C-TiO2 is amorphous, it shows a remarkable visible-light photocatalytic activity higher than that of nitrogen-doped TiO2 (N-TiO2 due to its significant surface area (530 m2/g and pore-rich structure. X-ray photoelectron, electron paramagnetic resonance, and UV-Vis diffuse reflectance spectroscopy reveal that the as-prepared porous C-TiO2 photocatalyst contains Ti–O–C bonds which result in visible-light absorption of the material at wavelengths less than 550 nm. Furthermore, it is discovered that the Ti–O–C bonds in the as-prepared C-TiO2 is easily transformed to coke-type species under mild thermal treatment (200°C. The resulting coke-containing porous TiO2 is an even better visible-light photocatalyst, almost twice as effective as N-TiO2, because of its stronger visible-light absorption. The Ti–O–C and the coke-containing porous TiO2 materials follow two different mechanisms in the visible-light photocatalysis process for degradation of methylene blue.

  18. Effect of sintering conditions on the microstructural and mechanical characteristics of porous magnesium materials prepared by powder metallurgy.

    Science.gov (United States)

    Čapek, Jaroslav; Vojtěch, Dalibor

    2014-02-01

    There has recently been an increased demand for porous magnesium materials in many applications, especially in the medical field. Powder metallurgy appears to be a promising approach for the preparation of such materials. Many works have dealt with the preparation of porous magnesium; however, the effect of sintering conditions on material properties has rarely been investigated. In this work, we investigated porous magnesium samples that were prepared by powder metallurgy using ammonium bicarbonate spacer particles. The effects of the purity of the argon atmosphere and sintering time on the microstructure (SEM, EDX and XRD) and mechanical behaviour (universal loading machine and Vickers hardness tester) of porous magnesium were studied. The porosities of the prepared samples ranged from 24 to 29 vol.% depending on the sintering conditions. The purity of atmosphere played a significant role when the sintering time exceeded 6h. Under a gettered argon atmosphere, a prolonged sintering time enhanced diffusion connections between magnesium particles and improved the mechanical properties of the samples, whereas under a technical argon atmosphere, oxidation at the particle surfaces caused deterioration in the mechanical properties of the samples. These results suggest that a refined atmosphere is required to improve the mechanical properties of porous magnesium.

  19. Optimization of Preparation Program for Biomass Based Porous Active Carbon by Response Surface Methodology Based on Adsorptive Property

    Directory of Open Access Journals (Sweden)

    ZHANG Hao

    2017-06-01

    Full Text Available With waste walnut shell as raw material, biomass based porous active carbon was made by microwave oven method. The effects of microwave power, activation time and mass fraction of phosphoric acid on adsorptive property of biomass based porous active carbon in the process of physical activation of active carbon precursor were studied by response surface method and numerical simulation method, the preparation plan of biomass based porous active carbon was optimized, and the optimal biomass based porous active carbon property was characterized. The results show that three factors affect the adsorptive property of biomass based porous active carbon, but the effect of microwave power is obviously more significant than that of mass fraction of phosphoric acid, and the effect of mass fraction of phosphoric acid is more significant than that of activation time. The optimized preparation conditions are:microwave power is 746W, activation time is 11.2min and mass fraction of phosphoric acid is 85.9% in the process of physical activation of activated carbon precursor by microwave heating method. For the optimal biomass based porous active carbon, the adsorption value of iodine is 1074.57mg/g, adsorption value of methylene blue is 294.4mL/g and gain rate is 52.1%.

  20. Light-Driven Preparation, Microstructure, and Visible-Light Photocatalytic Property of Porous Carbon-Doped TiO2

    OpenAIRE

    Xiao-Xin Zou; Guo-Dong Li; Jun Zhao; Juan Su; Xiao Wei; Kai-Xue Wang; Yu-Ning Wang; Jie-Sheng Chen

    2012-01-01

    Highly porous carbon-doped TiO2 (C-TiO2) has been prepared, for the first time, through a light-driven approach using crystalline titanium glycolate (TG) as the single-source precursor. Although the nonthermally prepared porous C-TiO2 is amorphous, it shows a remarkable visible-light photocatalytic activity higher than that of nitrogen-doped TiO2 (N-TiO2) due to its significant surface area (530 m2/g) and pore-rich structure. X-ray photoelectron, electron paramagnetic resonance, and UV-Vis di...

  1. Preparation,structure and properties of porous polyimide films via PAA/PU alloy

    Institute of Scientific and Technical Information of China (English)

    LIU Jiugui; JIANG Lizhong; ZHAN Jiayu; WU Dezhen; JIN Riguang

    2007-01-01

    A new route to porous polyimide(PI)films with pore sizes in the nanometer regime was developed.A polyamic acid(PAA)/polyurethane(PU)blend with PU as the disperse phase was first prepared via in situ polymerization of pyromellitic dianhydride and 4,4-oxydianiline in PU solutions.Porous PI films were obtained from PAAJPU films by thermolysis of PU at 360℃ and imidization of PAA at 300℃,respectively.Fourier transform infrared spectroscopy and thermal gravimetric analysis were used to detect the imidization and thermolysis processes of PAA/PU blends under thermal treatment.The microporous structure of the PI films was observed by transmission electron microscopy.It was found that the size and content of pores increased with an increase in the PU mass fraction in the PAA/PU blend up to 20%.Because of the existence of nanopores,the dielectric constant of PI films decreased by a wide margin and was less than 2.0 at a PU mass fraction of 20%.It implies that this is an effective means to reduce the dielectric constant of PI,but it also causes the decrease of tensile strength and the rise of water absorption.

  2. Hg(II) adsorption using amidoximated porous acrylonitrile/itaconic copolymers prepared by suspended emulsion polymerization.

    Science.gov (United States)

    Ji, Chunnuan; Qu, Rongjun; Chen, Hou; Liu, Xiguang; Sun, Changmei; Ma, Caixia

    2016-01-01

    Initially, porous acrylonitrile/itaconic acid copolymers (AN/IA) were prepared by suspended emulsion polymerization. Successively, the cyano groups in AN/IA copolymers were converted to amidoxime (AO) groups by the reaction with hydroxylamine hydrochloride. The structures of the AN/IA and amidoximated AN/IA (AO AN/IA) were characterized by infrared spectroscopy, scanning electron microscopy, and porous structural analysis. The adsorption properties of AO AN/IA for Hg(II) were investigated. The results show that AO AN/IA has mesopores and macropores, and surface area of 11.71 m(2) g(-1). It was found that AO AN/IA has higher affinity for Hg(II), with the maximum adsorption capacity of 84.25 mg g(-1). The AO AN/IA also can effectively remove Hg(II) from different binary metal ion mixture systems. Furthermore, the adsorption kinetics and thermodynamics were studied in detail. The adsorption equilibrium can quickly be achieved in 4 h determined by an adsorption kinetics study. The adsorption process is found to belong to the second-order model, and can be described by the Freundlich model.

  3. Porous shell/dense core structures prepared in tungsten phosphate glass through template-free route

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento Correa, Deleon; Alves, Oswaldo Luiz [Institute of Chemistry, University of Campinas - UNICAMP, Campinas, SP (Brazil); Odone Mazali, Italo, E-mail: mazali@iqm.unicamp.br [Institute of Chemistry, University of Campinas - UNICAMP, Campinas, SP (Brazil)

    2010-07-01

    The preparation of the 11.7Li{sub 2}O-39.7WO{sub 3}-10.9CaO-37.7P{sub 2}O{sub 5} glass (pgLWCP) was based on a one-step heat treatment of the 6Li{sub 2}O-18WO{sub 3}-43CaO-33P{sub 2}O{sub 5} (gLWCP) glass followed by leaching of the {beta}-Ca{sub 2}P{sub 2}O{sub 7} phase formed during the crystallization process. The porous structure was formed in the region formerly occupied by the {beta}-Ca{sub 2}P{sub 2}O{sub 7} phase. The gLWCP undergoes devitrification through surface crystallization. This process occurs after a thermal treatment in lower temperature and in a shorter period of time than that required for the complete crystallization. After acid leaching treatment, we obtained a core-/shell-like structure with a very well-defined dense glass (gLWCP)/porous glass (pgLWCP) interface. The pgLWCP exhibits reversible coloration-decoloration reactions.

  4. Porous TiO2-coated Magnetic Core-Shell Nanocomposites: Preparation and Enhanced Photocatalytic Activity

    Institute of Scientific and Technical Information of China (English)

    LIU Hongfei; JI Shengfu; ZHENG Yuanyuan; LI Ming; YANG Hao

    2013-01-01

    The core-shell structured TiO2/SiO2@Fe3O4 photocatalysts were prepared using Fe3O4 as magnetic core,tetraethoxysilane (TEOS) as silica source and tetrabutyl titanate (TBOT) as titanium sources.The as-obtained structure was composed of a SiO2@Fe3O4 core and a porous TiO2 shell.The diameter of SiO2@Fe3O4 core was about 205 nm with thickness of porous TiO2 of about 5-6 nm.The 9%TiO2/6% SiO2@Fe3O4 microspheres possess the highest BET surface area and the BJH pore volume,which are 373.5 m2·g-1 and 0.28 cm3·g-1,respectively.The 9%TiO2/6%SiO2@Fe3O4 photocatalyst exhibited an excellent performance for the degradation of methyl orange and methylene blue dyes.Two different dyes were completely decolorized in 60 rain under UV irradiation.The photocatalytic activity and the amount of catalyst were almost not decrease after recycling for 6 times by using external magnetic field.

  5. Polypropylene nonwoven surface modified through introducing porous microspheres: Preparation, characterization and adsorption

    Science.gov (United States)

    Du, Xiao; Wei, Junfu; Liu, Wei; Zhou, Xiangyu; Dai, Danyang

    2016-01-01

    A new porous fabric adsorbent (PM/PP nonwoven) was prepared by hydrogen bonding self-assembly method, in which poly(divinylbenzene-co-4-vinylpyridine) microspheres were introduced onto the surface of PP-g-AA (polypropylene grafted acrylic acid) nonwoven. The effects of the main conditions for self-assembly reaction such as mass ratio of microsphere to nonwoven, pH and the grafting degree of acrylic acid were studied. In addition, the adsorption mechanisms and interactions for three VOCs (styrene, cyclohexane, acetone) were systematically elucidated. The resulting 28.2% PM/PP nonwoven obtained a higher adsorption amount (52.8 mg/g) of styrene vapor, which was 88 times greater than that of original PP nonwoven. Meanwhile, the kinetic studies suggested that the Yoon and Nelson model is suitable to describe the adsorption mechanism of styrene over the modified nonwovens. Adsorption and pressure drop data showed that PM/PP nonwoven had good adsorption ability and air permeability due to its abundant functional groups and porous structures. Taken together, it is expected that PM/PP nonwoven would be a promising adsorbent for removal of VOCs from the gas streams.

  6. Preparation of magnetic hierarchically porous microspheres with temperature-controlled wettability for removal of oils.

    Science.gov (United States)

    Tao, Shengyang; Ding, Yunzhe; Jiang, Lei; Li, Guangtao

    2017-04-15

    A series of monodispersed microspheres with hierarchically porous structures were prepared by microfluidic devices. Phase separation of the silica sol in microdroplets was adopted to construct these structures. The effects of velocity ratios (for both the continuous and the dispersed phases), collection solvents and calcination temperatures were investigated. The diameters of the microspheres were tuned from 148μm to 940μm by adjusting the velocity ratio. Tests revealed that the surface areas and pore volumes of the microspheres can reach 495m(2)g(-1) and 0.6068mlg(-1), respectively. The macroporous structure can be controlled by the collection solvents, and the wettability of the microspheres is determined by the calcination temperature. A calcination temperature of 450°C leads to a hydrophilic surface property. Fe3O4 nanoparticles were added to the silica sol to form magnetic microspheres, and the porous structure was not affected. This kind of hybrid microsphere adsorbs 3.29 times its own weight in toluene. These spheres can adsorb oil on water surfaces, and then be removed from the water with an external magnetic field. The microspheres can be recovered and reused more than 10 times. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. 多孔陶瓷分离膜支撑体的制备%Preparation of Porous Ceramic Separation Membrane Supports

    Institute of Scientific and Technical Information of China (English)

    刘亚会; 汪建根

    2012-01-01

    采用氧化铝为主要原料制备出多孔陶瓷分离膜支撑体,对原料粉体做了TG/DSC曲线分析.研究了支撑体的烧结温度对收缩率的影响;烧结温度、保温时间和原料粉体粒径对孔结构、孔径的影响;造孔剂用量对孔隙率的影响.结果表明:在烧结温度1 200℃,保温时间4h,造孔剂用量(即造孔剂质量占原料总质量的百分数,下同)大于20%的条件下,制备出孔径分布均匀,孔隙率大于50%,符合透水要求的多孔陶瓷分离膜支撑体.%Porous ceramic separation membrane supports are prepared using alumina fine as the main raw materials, and the TG/DSC curves of the powder of raw materials are analyzed. The effect of the supports' sintering temperature on the shrinkage rate is studied. The effects of different sintering temperature, holding time and materials powder particle size on pore structure and size of the supports are also studied. The effect of the pore former dosage on porosity is also within the scope of study. The results show that porous ceramics separation membrane supports of uniform pore size distribution and with porosity more than 50% and pervious to water can be prepared under the following optimum conditions:sintering temperature being 1 200 ℃, holding time being 4 h, and porous agent being more than 20%.

  8. Aging Time Effect on Porous Characteristics of Natural Mud-based Silica Prepared by Hydrothermal-Coprecipitation Route

    Science.gov (United States)

    Ubaid, A.; Hidayat, N.; Munasir

    2017-05-01

    In this present study, we report the influence of aging time on porous characteristics and chemical bonding within structurally related silicates of silica. The silica was well prepared by using a combination of hydrothermal and coprecipitation methods. Local natural mud from Sidoarjo, Indonesia was preferred as a starting material, rather than the expensive commercial ones. The aging time was set at 20, 24, 28, and 32 hours. The X-ray fluorescence (XRF) test revealed that the produced porous silica has a purity of 98.9%. The Fourier Transform of Infra-Red (FTIR) analysis showed that ≡Si-OH and ≡Si-O -Si≡ functional groups were found in the samples. The pores of the silica, after Brunauer-Emmett-Teller (BET) measurement, found to be macropore and mesopore. The prepared silica with different porous characteristics were strongly influenced by the chemical activities during the synthesis, known as syneresis and Ostwald processes.

  9. Preparation and Characterization of Non-porous Superparamagnetic Microspheres with Epoxy Groups by Dispersion Polymerization

    Institute of Scientific and Technical Information of China (English)

    马志亚; 官月平; 刘先桥; 刘会洲

    2005-01-01

    Non-porous superparamagnetic polymer microspheres with epoxy groups were prepared by dispersion polymerization of glycidyl methacrylate (GMA) in the presence of magnetic iron oxide (Fe3O4) nanoparticles coated with oleic acid. The polymerization was carried out in the ethanol/water medium using polyvinylpyrrolidone (PVP) and 2,2’-azobisisobutyronitrile (AIBN) as stabilizer and initiator, respectively. The magnetic microspheres obtained were characterized with scanning electron microscopy (SEM), vibrating sample magnetometry (VSM) and Fourier transform infrared spectroscopy (FTIR). The results showed that the magnetic microspheres had an average size of-1μm with superparamagnetic characteristics. The saturation magnetization was found to be 4.5emu.g-1. There was abundance of epoxy groups with density of 0.028 mmol·g-1 in microspheres. The magnetic PGMA microspheres have extensive potential uses in magnetic bioseparation and biotechnology.

  10. Preparation and Characterization of Porous Yttrium Oxide Powders with High Specific Surface Area

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The porous cubic yttrium oxides with high specific surface area were prepared by the explosive decomposition of yttrium nitrate and its complex formed with methyl salicylate. The specific surface area and properties of powders synthesized at various temperatures were characterized using BET, X-ray diffraction (XRD), infrared spectra (IR), and scanning electron microscopy (SEM). The results indicate that the highest specific surface area is found to be 65.37 m2*g-1 at the calcination temperature of 600 ℃, and then decreases to 20.33 m2*g-1 with the calcination temperature rising from 600 to 900 ℃. The powders show strong surface activity for adsorping water and carbon dioxide in air, which also decreases with the rising calcination temperature. The drop both on the surface area and surface activity of samples at higher temperatures may be due to pore-narrowing(sintering) effects.

  11. Optical Characterization of SERS Substrates Based on Porous Au Films Prepared by Pulsed Laser Deposition

    Directory of Open Access Journals (Sweden)

    V. V. Strelchuk

    2015-01-01

    Full Text Available The SERS (surface enhanced Raman spectroscopy substrates based on nanocomposite porous films with gold nanoparticles (Au NPs arrays were formed using the method of the pulsed laser deposition from the back low-energy flux of erosion torch particles on the glass substrate fixed at the target plain. The dependencies of porosity, and morphology of the surface of the film regions located near and far from the torch axis on the laser ablation regime, laser pulses energy density, their number, and argon pressure in the vacuum chamber, were ascertained. The Au NPs arrays with the controllable extinction spectra caused by the local surface plasmon resonance were prepared. The possibility of the formation of SERS substrates for the detection of the Rhodamine 6G molecules with the concentration 10−10 Mol/L with the enhancement factor 4·107 was shown.

  12. Preparation of Carbon Nanotubes by the Catalysis of Polymer Metal Complex on Porous Al203 Matrix

    Institute of Scientific and Technical Information of China (English)

    SHI YanLi; ZHANG XiaoGang; LI HuLin

    2001-01-01

    @@ At present, synthesis of carbon nanotubes (CNTs) is normally conducted on a vapor-to-solid interface at ca. 500-3500℃ via various vapor phase methods, such as are discharge, laser ablation, catalytic pyrolysis and chemical vapor deposition, etc.1-2 Recently, channel materials (such as channels of alumina and of AlPO4-5 zeolite) 3 have been utilized as solid-state templates to grow CNTs inside the channel. Here we described a novel method to prepare the carbon nanotubes based on the decomposition of C2H2 gas on the Co-Ni catalyst anchored by polymer complex on the porous A12O3 matrix. The degree of graphitization of synthesized CNTs and catalysts are of great interest.

  13. Preparation of Carbon Nanotubes by the Catalysis of Polymer Metal Complex on Porous Al203 Matrix

    Institute of Scientific and Technical Information of China (English)

    SHI; YanLi

    2001-01-01

    At present, synthesis of carbon nanotubes (CNTs) is normally conducted on a vapor-to-solid interface at ca. 500-3500℃ via various vapor phase methods, such as are discharge, laser ablation, catalytic pyrolysis and chemical vapor deposition, etc.1-2 Recently, channel materials (such as channels of alumina and of AlPO4-5 zeolite) 3 have been utilized as solid-state templates to grow CNTs inside the channel. Here we described a novel method to prepare the carbon nanotubes based on the decomposition of C2H2 gas on the Co-Ni catalyst anchored by polymer complex on the porous A12O3 matrix. The degree of graphitization of synthesized CNTs and catalysts are of great interest.  ……

  14. Surface Functionality Features of Porous Silicon Prepared and Treated in Different Conditions

    Directory of Open Access Journals (Sweden)

    Yu. M. Spivak

    2016-01-01

    Full Text Available Hydrophilic layers of porous silicon are prepared by single- or two-step anodization and characterized by evaluating their surface hydrophilicity and contents of functional groups using IR spectroscopy and adsorption of acid-base indicators with different pKa values. The surface functional composition of the synthesized samples is shown to be adjustable depending on the anodization current density. The surface of samples obtained at anodization current density 30 mA/cm2 is predominantly occupied with pKa 2.5 corresponding to ≡Si–OH groups. The increase of current density to 80 mA/cm2 results in the increase of surface functional nonuniformity with the formation of versatile centers, primarily Lewis acidic sites corresponding to Si atoms, as indicated by selective indicator adsorption in agreement with the disappearance of Si–H bonds in IR spectra and overall surface disordering according to SEM and AFM data.

  15. Preparation of functionalized porous nano-γ-Al2O3 powders employing colophony extract

    Directory of Open Access Journals (Sweden)

    Ángela B. Sifontes

    2014-12-01

    Full Text Available This study reports the synthesis of porous nano alumina employing carboxylato-alumoxanes [Al(Ox(OHy(O2CRz]n as precursors for controlling the pore size, pore size distribution and porosity of the alumina, using a new process ecofriendly. The carboxylato-alumoxanes was prepared by the reaction of boehmite with carboxylic acids. The boehmite was obtained by the hydrolysis of aluminum alkoxide in an aqueous solution. The colophony extract is employed as a source of carboxylic acids. The materials were characterized, using XRD, TGA, N2 physical adsorption, SEM, TEM, NMR and FTIR. A mechanism was proposed for the formation of the synthesized structures. TEM measurements confirmed particle size ranged from 5 to 8 nm.

  16. Preparation of Strontium Bismuth Tantalum (SBT) Fine Powder by Sol-Gel Process Using Bismuth Subnitrate as Bismuth Source

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Strontium bismuth tantalum (SBT) fine power was prepared by Sol-Gel method. Pentaethoxy tantalum, strontium acetate and bismuth subnitrate were used as raw materials, and were dissolved in proper order in ethylene glycol to form transparent sol. The mixed precursor was dried at 80°C and annealed at 800°C for 1 h. Crystallized nanometer sized SBT fine powder was obtained and characterized by XRD.

  17. Preparation of ferromagnetic binary alloy fine fibers byorganic gel-thermal reduction process

    Institute of Scientific and Technical Information of China (English)

    SHEN Xiang-qian; CAO Kai; ZHOU Jian-xin

    2006-01-01

    Ferromagnetic metal fibers with a high aspect ratio (length/diameter) are attractive for use as high performance electromagnetic interference shielding materials. Ferromagnetic binary alloy fine fibers of iron-nickel, iron-cobalt and cobalt-nickel were prepared by the organic gel-thermal reduction process from the raw materials of critic acid and metal salts. These alloy fibers synthesized were featured with a diameter of about 1 μm and a length as long as 1 m. The structure, thermal decomposition process and morphologies of the gel precursors and fibers derived from thermal reduction of the gel precursors were characterized by FTIR, XRD, TG/DSC and SEM. The gel spinnability largely depends on the molecular structure of metal- carboxylates formed during the gel formation. The gel consisting of linear-type structural molecules shows good spinnability.

  18. Preparation and Photocatalytic Activity of TiO2/Fine Char for Removal of Rhodamine B

    Directory of Open Access Journals (Sweden)

    Mingjie Ma

    2015-01-01

    Full Text Available TiO2/fine char (FC photocatalyst was prepared via sol-gel method with tetrabutyl titanate as the precursor and FC as the carrier. The structural property of TiO2/FC photocatalyst was investigated by X-ray diffraction (XRD and scanning electron microscopy (SEM, and the photocatalytic activity of TiO2/FC was evaluated by photocatalytic degradation of rhodamine B (RhB aqueous solution under UV light irradiation. The results showed that TiO2 was successfully coated on the surface of FC, and the TiO2/FC photocatalyst had better photocatalytic efficiency and stability for degradation of RhB under UV light illumination as compared to that of the pure TiO2 and FC. The study provided a novel way for the application of FC to the photocatalytic degradation of organic wastes.

  19. Preparation of porous poly(trimethylene carbonate structures for controlled release applications using high pressure CO2

    NARCIS (Netherlands)

    Nalawade, S.P.; Hennink, W.E.; Westerman, D.; Feijen, J.; Sam, A.P.; Leeke, G.; Santos, R.C.D.; Grijpma, Dirk W.; Feijen, Jan

    2008-01-01

    Porous poly(trimethylene carbonate) structures can readily be prepared using high pressure CO2. Differences in CO2 solubility in the polymer matrix at the different processing temperatures and pressures lead to different pore morphologies upon depressurization. Furthermore, crystallization of the

  20. Preparation of porous poly(trimethylene carbonate) structures for controlled release applications using high pressure CO2

    NARCIS (Netherlands)

    Nalawade, S.P.; Westerman, D.; Leeke, G.; Santos, R.C.D.; Grijpma, D.W.; Feijen, J.

    2008-01-01

    Porous poly(trimethylene carbonate) structures can readily be prepared using high pressure CO2. Differences in CO2 solubility in the polymer matrix at the different processing temperatures and pressures lead to different pore morphologies upon depressurization. Furthermore, crystallization of the in

  1. Preparation and characterization of porous crosslinked collagenous matrices containing bioavailable chondroitin sulphate

    NARCIS (Netherlands)

    Pieper, J.S.; Oosterhof, A.; Dijkstra, Pieter J.; Veerkamp, J.H.; van Kuppevelt, T.H.

    1999-01-01

    Porous collagen matrices with defined physical, chemical and biological characteristics are interesting materials for tissue engineering. Attachment of glycosaminoglycans (GAGs) may add to these characteristics and valorize collagen. In this study, porous type I collagen matrices were crosslinked

  2. Preparation and characterization of porous crosslinked collagenous matrices containing bioavailable chondroitin sulphate

    NARCIS (Netherlands)

    Pieper, J.S.; Oosterhof, A.; Dijkstra, P.J.; Veerkamp, J.H.; Kuppevelt, van T.H.

    1999-01-01

    Porous collagen matrices with defined physical, chemical and biological characteristics are interesting materials for tissue engineering. Attachment of glycosaminoglycans (GAGs) may add to these characteristics and valorize collagen. In this study, porous type I collagen matrices were crosslinked us

  3. Hollow CuO nanospheres uniformly anchored on porous Si nanowires: preparation and their potential use as electrochemical sensors

    Science.gov (United States)

    Guo, Zheng; Seol, Myeong-Lok; Kim, Moon-Seok; Ahn, Jae-Hyuk; Choi, Yang-Kyu; Liu, Jin-Huai; Huang, Xing-Jiu

    2012-11-01

    Hollow CuO nanospheres have been prepared via a reduction reaction of copper ions on porous Si nanowires combined with calcination in air and uniformly anchored on their surfaces. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) were employed to characterize and analyze as-synthesized samples. The results reveal that Si nanowires fabricated from heavily doped Si wafer are formed with a meso-porous structure by an Ag-assisted etching approach, and Cu nanoparticles are formed and uniformly decorated on the Si nanowires through a reaction of copper ions reduced by silicon. After annealing in air, Cu nanoparticles are in situ oxidized and transformed into CuO, leading to the formation of hollow nanospheres because of the Kirkendall effect. The diameter size of as-prepared CuO hollow spheres anchored on porous Si nanowires is mainly around 30 nm. Finally, in order to illuminate the advantages of this novel hybrid nanostructure of nanosized hollow spheres supported on porous nanowires, its electrochemical sensing performance to hydrazine as an example has been further investigated. The results confirm that it is a good potential application to detect hydrazine.Hollow CuO nanospheres have been prepared via a reduction reaction of copper ions on porous Si nanowires combined with calcination in air and uniformly anchored on their surfaces. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) were employed to characterize and analyze as-synthesized samples. The results reveal that Si nanowires fabricated from heavily doped Si wafer are formed with a meso-porous structure by an Ag-assisted etching approach, and Cu nanoparticles are formed and uniformly decorated on the Si nanowires through a reaction of copper ions reduced by silicon. After annealing in air, Cu nanoparticles are in situ oxidized and transformed into CuO, leading to the

  4. Synthesis of calcium phosphates and porous hydroxyapatite beads prepared by emulsion method

    Energy Technology Data Exchange (ETDEWEB)

    Chen, B.-H. [Faculty of Biotechnology, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan (China); Chen, K.-I [Department of Electronics Engineering and Computer Science, Tung-Fang Institute of Technology, 100 Dungfang Road, Hunei, Kaohsiung, Taiwan (China); Ho, M.-L. [Department of Physiology, Kaohsiung Medical University, Kaohsiung 807, Taiwan (China); Chen, H.-N. [Faculty of Medicinal and Applied Chemistry, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan (China); Chen, W.-C. [Faculty of Dentistry, Kaohsiung Medical University, Kaohsiung 807, Taiwan (China); Wang, C.-K. [Faculty of Medicinal and Applied Chemistry, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 807, Taiwan (China)], E-mail: ckwang@kmu.edu.tw

    2009-01-15

    Raw calcium phosphates were synthesized via a chemical reaction between 0.5 M orthophosphoric acid and 0.5 M calcium hydroxide. Hydroxyapatite (HAp), {beta}-tricalcium phosphate ({beta}-TCP) or biphase calcium phosphate (BCP) comprising HAp and {beta}-TCP were obtained by changing pH value, Ca/P ratio, and the addition of glycerol. The as-synthesized and heat-treated powders were analyzed by X-ray diffraction (XRD) and Fourier transformation infrared spectrometry (FTIR). Thermal stability of the pure apatite phase was obtained to be 1300 deg. C, while synthesis was done at the pH value of 10.0 with a Ca/P ratio of 2.0 and a temperature of 37 deg. C. Besides, the {beta}-TCP phase (with higher purity) was achieved at 800 deg. C, whose synthesis was done at pH 6.4 with a Ca/P ratio of 1.5 and a temperature of 37 deg. C. Therefore, the biphase bioceramics comprising of HAp and {beta}-TCP could be obtained, since it was manipulated suitably. The HAp raw material was subjected to a simple emulsion method for the preparation of porous beads. They should have the advantage of exhibiting higher adsorptive ability and osteoconductivity in comparison with the sintered dense apatite. Additionally, the porous beads of apatite were demonstrated to be non-toxic to cells, and should be suitable for the use as a scaffold of cultured bone and bone graft material, as well as for drug delivery systems.

  5. Preparation of Zeolite X Membranes on Porous Ceramic Substrates with Zeolite Seeds

    Institute of Scientific and Technical Information of China (English)

    Zhongqiang Xu; Qingling Chen; Guanzhong Lu

    2002-01-01

    Zeolite X membranes were investigated by in-situ hydrothermal synthesis on porous ceramic tubes precoated with zeolite X seeds or precursor amorphous aluminosilicate, and porous α-Al2O3 ceramic tubes with a pore size of 50 200 nm were employed as supports. Zeolite X crystals were synthesized by the classic method and mixed into deionized water as a slurry with a concentration of 0.2 0.5wt%, having a range of crystal sizes from 0.2 to 2μm. Crystal seeds were pressed into the pores near the inner surface of the ceramic tubes, and crystallization took place at 95℃ for 24-96 h. It was also investigated that Boehmite sol added with zeolite X seeds was precoated on ceramic supports to form a layer of γ-Al2O3 by heating, and hydrothermal crystallization could then take place to prepare the zeolite membranes on the composite ceramic tubes. The crystal species were characterized by XRD, and the morphology of the supports subjected to crystallization was characterized by SEM. The composite zeolite membranes have zeolitic top-layers with a thickness of 10-25 μm, and zeolite crystals can be intruded into pores of the supports as deeply as 100μm. The experimental results indicate that the precoating of zeolitic seeds on supports is beneficial to crystallization by shortening the synthesis time and improving the membrane strength. The resulting zeolite X membrane shows permselectivity to tri-n-butylamine((C4H9)3N) over perfluro-tributyl-amine ((C4Fg)3N), and a permeance ratio of 57 for ((C4Hg)3N to (C4F9)3N could be reached at 350℃. Permeances of BZ, EB and TIPB through the zeolite membrane were also measured and were found to slightly increase with temperature.

  6. Development of an Ultra-fine Coal Dewatering Technology and an Integrated Flotation-Dewatering System for Coal Preparation Plants

    Energy Technology Data Exchange (ETDEWEB)

    Wu Zhang; David Yang; Amar Amarnath; Iftikhar Huq; Scott O' Brien; Jim Williams

    2006-12-22

    The project proposal was approved for only the phase I period. The goal for this Phase I project was to develop an industrial model that can perform continuous and efficient dewatering of fine coal slurries of the previous flotation process to fine coal cake of {approx}15% water content from 50-70%. The feasibility of this model should be demonstrated experimentally using a lab scale setup. The Phase I project was originally for one year, from May 2005 to May 2006. With DOE approval, the project was extended to Dec. 2006 without additional cost from DOE to accomplish the work. Water has been used in mining for a number of purposes such as a carrier, washing liquid, dust-catching media, fire-retardation media, temperature-control media, and solvent. When coal is cleaned in wet-processing circuits, waste streams containing water, fine coal, and noncombustible particles (ash-forming minerals) are produced. In many coal preparation plants, the fine waste stream is fed into a series of selection processes where fine coal particles are recovered from the mixture to form diluted coal fine slurries. A dewatering process is then needed to reduce the water content to about 15%-20% so that the product is marketable. However, in the dewatering process currently used in coal preparation plants, coal fines smaller than 45 micrometers are lost, and in many other plants, coal fines up to 100 micrometers are also wasted. These not-recovered coal fines are mixed with water and mineral particles of the similar particle size range and discharged to impoundment. The wasted water from coal preparation plants containing unrecoverable coal fine and mineral particles are called tailings. With time the amount of wastewater accumulates occupying vast land space while it appears as threat to the environment. This project developed a special extruder and demonstrated its application in solid-liquid separation of coal slurry, tailings containing coal fines mostly less than 50 micron. The

  7. Self-assembly of ZnO nanoparticles and preparation of bulk ZnO porous nanosolids

    Institute of Scientific and Technical Information of China (English)

    LIU Xiulin; XU Hongyan; YU Lili; LI Mei; WANG Chengjian; CUI Deliang; JIANG Minhua

    2005-01-01

    Novel bulk ZnO porous nanosolids were prepared by a unique solvothermal hot-press method, using ZnO nanoparticles and several kinds of solvents as the starting materials. It was found from the experiments that ZnO nanoparticles underwent a "self-assembly process" under some specific hydrothermal hot-press conditions. As a result, some "nanoflowers" formed. The results showed that porous nanosolids with uniform pore diameters could be obtained when water distributed uniformly among the ZnO nanoparticles. On the contrary, if the uniformity of the distribution of water was poor, "nanoflowers" would appear in the water-rich region. It was also found that the photoluminescence of ZnO porous nanosolids was affected by the self-assembly phenomenon. In addition, the results also showed that, both the volume and diameters of the pores could be adjusted by changing either the hot-press temperature, pressure or the kinds of solvents.

  8. Porous poly(L-lactic acid) sheet prepared by stretching with starch particles as filler for tissue engineering.

    Science.gov (United States)

    Ju, Dandan; Han, Lijing; Li, Zonglin; Chen, Yunjing; Wang, Qingjiang; Bian, Junjia; Dong, Lisong

    2016-05-20

    Porous poly(L-lactic acid) (PLLA) sheets were prepared by uniaxial stretching PLLA sheets containing starch filler. Here, the starch filler content, stretching ratio, stretching rate and stretching temperature are important factors to influence the structure of the porous PLLA sheets, therefore, they have been investigated in detail. The pore size distribution and tortuosity were characterized by Mercury Intrusion Porosimetry. The results revealed that the porosity and pore size enlarged with the increase of the starch filler content and stretching ratio, while shrank with the rise of stretching temperature. On the other hand, the pore structure almost had no changes with the stretching rate ranging between 5 and 40 mm/min. In order to test and verify that the porous PLLA sheet was suitable for the tissue engineering, the starch particles were removed by selective enzymatic degradation and its in vitro biocompatibility to osteoblast-like MC3T3-E1 cells was investigated.

  9. Preparation and sonocatalytic activity of monodisperse porous bread-like CuO via thermal decomposition of copper oxalate precursors

    Science.gov (United States)

    Zhang, Lihui; Liu, Rong; Yang, Heqing

    2012-04-01

    Porous bread-like CuO have been obtained via the thermal decomposition of copper oxalate precursor synthesized by the room temperature reaction of Cu(NO3)2 with Na2C2O4 in water. These bread-like CuO with the monoclinic structure are well dispersed with good monodispersity, their diameters are about 1.5 μm. The sonocatalytic activity of porous CuO for the degradation of acid scarlet dye was studied. It was found that the as-prepared porous CuO nanostructures exhibit efficient sonocatalytic ability for the degradation of acid scarlet dye in the presence of H2O2, which are expected to be useful in the treatment of non- or low-transparent wastewaters.

  10. A novel method for preparing ultra-fine alumina-borate oxide fibres via an electrospinning technique

    Science.gov (United States)

    Dai, Hongqin; Gong, Jian; Kim, Hakyong; Lee, Doukrae

    2002-10-01

    Alumina-borate/PVA composite fibres were prepared using sol-gel processing and an electrospinning technique. After calcination of the thin fibres, ultra-fine fibres of alumina-borate oxide with a diameter of about 550 nm could be prepared. The fibres were characterized by SEM, XRD and FT-IR. The results showed that the crystalline phase and morphology of alumina-borate fibres were largely influenced by the calcination temperature.

  11. Preparation and oxygen-sensing properties of TiO2 porous thin films on alumina substrate

    Institute of Scientific and Technical Information of China (English)

    LI Ming-li; XU Ming-xia; LI Yan

    2006-01-01

    The titanium dioxide sols were synthesized with tetrabutyl titanate as precursor,diethanolamine(DEA) as complexing agent ,polyethylene glycol (PEG) as organic template. The porous films were prepared by sol-gel method. The structures and morphology of the titanium dioxide porous films were characterized by FE-SEM. The formation mechanism of TiO2 porous films and the relation between the porous structure and oxygen-sensing properties of TiO2 films were studied. Ordered structure was formed by assembling between TiO2 colloid particles and the template molecules. PEG molecules acted on TiO2 colloid particles by hydrogen bond and bridge oxygen. The porous structure was formed after the organic template was decomposed when calcining the films. The diameter,amount and distribution of the pores in the films are related with the content of PEG.. The pore diameter increases with increasing of content of PEG and the pore density reaches the maximum at certain content. Oxygen-sensitivity and response speed of porous TiO2 films are improved compared with films without pores. Both the sensitivity and response speed increase with the increasing of pore diameter and pore density. Oxygen-sensitivity reaches 3 order of magnitude at 800 ℃. Its response time from H2/N2 to O2/N2 atmosphere and vice versa is about 0.11 s and 0.12 s respectively. Although the sensitivity and response speed increase,the resistance-temperature properties of porous films are not notably improved with the increasing of the content of PEG.

  12. Preparation of porous α-Fe2O3-supported Pt and its sensing performance to volatile organic compounds

    Institute of Scientific and Technical Information of China (English)

    Yuhong Cheng; Yanfei Kang; Liwei Wang; Yao Wang; Shurong Wang; Yujin Li; Wei Zhong; Liangqun Peng

    2012-01-01

    Porous α-Fe2O3 was synthesized by a simple hydrothermal treatment of FeCl3 aqueous solution followed by a calcination process.In the synthesis of porous α-Fe2O3,no templates or pore-directing agents were used.The as-prepared porous α-Fe2O3 was further employed as a support for loading Pt nanoparticles.The gas sensing performance of the obtained porous α-Fe2O3-supported Pt to VOCs was investigated.The sensor presented a high response and fast response-recovery characteristic to several VOCs including acetone,ether,methanol,ethanol,butanol and hexanol.Meanwhile,it exhibited a much higher response than the pure α-Fe2O3 at the operating temperature of 260℃.The enhanced sensing properties may be related to the unique porous structure of the α-Fe2O3 support and the promoting effect of active Pt nanoparticles for the sensing reactions.

  13. Porous tantalum coatings prepared by vacuum plasma spraying enhance bmscs osteogenic differentiation and bone regeneration in vitro and in vivo.

    Directory of Open Access Journals (Sweden)

    Ze Tang

    Full Text Available Tantalum, as a potential metallic implant biomaterial, is attracting more and more attention because of its excellent anticorrosion and biocompatibility. However, its significantly high elastic modulus and large mechanical incompatibility with bone tissue make it unsuitable for load-bearing implants. In this study, porous tantalum coatings were first successfully fabricated on titanium substrates by vacuum plasma spraying (VPS, which would exert the excellent biocompatibility of tantalum and alleviate the elastic modulus of tantalum for bone tissue. We evaluated cytocompatibility and osteogenesis activity of the porous tantalum coatings using human bone marrow stromal cells (hBMSCs and its ability to repair rabbit femur bone defects. The morphology and actin cytoskeletons of hBMSCs were observed via electron microscopy and confocal, and the cell viability, proliferation and osteogenic differentiation potential of hBMSCs were examined quantitatively by PrestoBlue assay, Ki67 immunofluorescence assay, real-time PCR technology and ALP staining. For in vivo detection, the repaired femur were evaluated by histomorphology and double fluorescence labeling 3 months postoperation. Porous tantalum coating surfaces promoted hBMSCs adhesion, proliferation, osteogenesis activity and had better osseointegration and faster new bone formation rate than titanium coating control. Our observation suggested that the porous tantalum coatings had good biocompatibility and could enhance osseoinductivity in vitro and promote new bone formation in vivo. The porous tantalum coatings prepared by VPS is a promising strategy for bone regeneration.

  14. Preparation of high strain porous polyvinyl alcohol/polyaniline composite and its applications in all-solid-state supercapacitor

    Science.gov (United States)

    Hu, Ruofei; Zheng, Junping

    2017-10-01

    Impacted by the rapid development of the wearable and portable devices, the demands for excellent flexibility and high specific capacitance have highlighted an urgent need for developing flexible energy storage devices. In this paper, we prepare a porous polyvinyl alcohol (PVA)/polyaniline (PANI) composite with perfect mechanical performance (strain deformations of 696%). Due to its three-dimensional (3D) porous structure, deformation of the PANI can be avoided when the composite is bent or stretched. The electrochemical performance of the porous PVA/PANI composite can be maintained so that it holds promise for stretchable energy storage devices. As a proof of concept, an all-solid-state supercapacitor is fabricated by using the porous PVA/PANI composite and exhibits a high areal capacitance of 300.9 mF cm-2 and long-life stability of 85% capacitance retention after 10,000 charge/discharge cycles. In particular, the supercapacitor can also withstand repeated bending and stretching with minimal effect on the electrochemical performance when no current collector is employed. The research presents a design approach of high strain porous composite and shows great promise for the development of stretchable energy storage devices.

  15. Incomparable hardness and modulus of biomimetic porous polyurethane films prepared by directional melt crystallization of a solvent

    Science.gov (United States)

    An, Suyeong; Kim, Byoungsoo; Lee, Jonghwi

    2017-07-01

    Porous materials with surprisingly diverse structures have been utilized in nature for many functional purposes. However, the structures and applications of porous man-made polymer materials have been limited by the use of processing techniques involving foaming agents. Herein, we demonstrate for the first time the outstanding hardness and modulus properties of an elastomer that originate from the novel processing approach applied. Polyurethane films of 100-μm thickness with biomimetic ordered porous structures were prepared using directional melt crystallization of a solvent and exhibited hardness and modulus values that were 6.8 and 4.3 times higher than those of the random pore structure, respectively. These values surpass the theoretical prediction of the typical model for porous materials, which works reasonably well for random pores but not for directional pores. Both the ordered and random pore structures exhibited similar porosities and pore sizes, which decreased with increasing solution concentration. This unexpectedly significant improvement of the hardness and modulus could open up new application areas for porous polymeric materials using this relatively novel processing technique.

  16. Preparation of Porous GaN Buffer and Its Influence on the Residual Stress of GaN Epilayers Grown by Hydride Vapor Phase Epitaxy

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The preparation of porous structure on the molecular beam epitaxy (MBE)-grown mixed-polarity GaN epilayers was reported by using the wet chemical etching method. The effect of this porous structure on the residual stress of subsequent-growth GaN epilayers was studied by Raman and photoluminescence (PL) spectrum.Substantial decrease in the biaxial stresse can be achieved by employing the porous buffers in the hydride vapour phase epitaxy (HVPE) epilayer growth.

  17. Preparation of fine nickel powders via reduction of nickel hydrazine complex precursors

    Institute of Scientific and Technical Information of China (English)

    HUANG Guo-yong; XU Sheng-ming; XU Gang; LI Lin-yan; ZHANG Li-feng

    2009-01-01

    Fine nickel(Ni) powders with controllable particle sizes were synthesized via the reduction of nickel hydrazine complex precursors of pure [Ni(N2H4)2]Cl2 and a mixture of [Ni(N2H4)2]Cl2 and [Ni(N2H4)3]Cl2 in aqueous solution. The mechanism of the formation of metallic Ni powders experiences the reduction of nickel hydroxide by hydrazine released from the ligand exchange reaction between nickel hydrazine complex and NaOH. In comparison with the method of preparing Ni powders from nickel salts, the method of making Ni powders via the reduction of nickel hydrazine complex precursors shows the advantages of using half dosage of hydrazine for complete reduction of nickel ions in solution, and the obtained Ni particles show less agglomeration and better dispersibility. Moreover, the average particle size of nickel powders can be controlled from 180 to 260 nm by adjusting the reaction molar ratio and concentration.

  18. Preparation of fine silicon particles from amorphous silicon monoxide by the disproportionation reaction

    Science.gov (United States)

    Mamiya, Mikito; Takei, Humihiko; Kikuchi, Masae; Uyeda, Chiaki

    2001-07-01

    Fine Si particles have been prepared by the disproportionation reaction of silicon monoxide (SiO), that is: 2SiO→Si+SiO 2. Amorphous powders of SiO are heated between 900°C and 1400°C in a flow of Ar and the obtained specimens are analyzed by X-ray powder diffraction and high-resolution transmission electron microscopy. The treatments between 1000°C and 1300°C for more than 0.5 h result in origination of Si particles dispersed in amorphous oxide media. The particle size varies from 1-3 to 20-40 nm, depending on the heating temperature. Kinetic analyses of the reaction reveal that the activation energy is 1.1 eV (82.1 kJ mol -1). The specimens annealed above 1350°C changes into a mixture of Si and cristobalite, suggesting a solid state transformation in the surrounding oxides from the amorphous to crystalline states.

  19. Preparation and thermal stability of porous alumina membranes with nano-pore arrays

    Science.gov (United States)

    Wang, Xue Hua; Li, Cheng Yong; Chen, Gui; He, Lei; Cao, Hong

    2010-03-01

    Porous alumina membranes (PAMs) were fabricated using a two-step oxidization method in oxalic acid. Polycrystalline PAMs have been prepared after annealing at different temperatures. The high-temperature properties of the PAMs were investigated using scanning electron microscopy, thermal analysis, X-ray diffraction and infrared spectrometer. At 870°C the amorphous alumina crystallizes to γ-Al2O3. Finally at 1228°C the alumina converts into the thermodynamically preferred phase, α-Al2O3. Differential thermal analysis showed that there was a gradual weight loss at about 900°C due to decomposed of oxalate. A mass of carboxylate ions and carboxylic groups were found in the infrared spectrum of PAMs, and reduced with the increasing of annealing temperature. Characteristic analysis with scanning electron microscopy shows that the pore structure of the PAMs was very stable and there was no detectable structural modification below 900°C, and microstructures of the pores changed slightly during the transformation from α-Al2O3 to γ-Al2O3 while increasing the annealing temperature.

  20. Preparation, antibacterial effects and corrosion resistant of porous Cu–TiO{sub 2} coatings

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Haibo; Zhang, Xiangyu, E-mail: zhangxiangyu@tyut.edu.cn; Geng, Zhenhua; Yin, Yan; Hang, Ruiqiang; Huang, Xiaobo; Yao, Xiaohong; Tang, Bin

    2014-07-01

    Antibacterial TiO{sub 2} coatings with different concentrations of Cu (Cu–TiO{sub 2}) were prepared by micro-arc oxidation (MAO) on pre-sputtered CuTi films. The effect of Cu concentrations in CuTi films on the MAO process was investigated. The Cu–TiO{sub 2} coatings were analyzed by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). The corrosion resistance of Cu–TiO{sub 2} coatings was evaluated via potentiodynamic polarization method. The antibacterial properties were assessed by two methods: spread plate method and fluorescence staining. The experimental results demonstrate that the coatings are porous and consist of anatase phase, rutile phase and unoxidized titanium. The CuTi films are almost completely oxidized and the thickness of all MAO coatings is about 5–10 μm. Cu mainly exists as CuO in the TiO{sub 2} coatings. The Cu–TiO{sub 2} coatings exhibit excellent antibacterial activities, and the antibacterial rate gradually rise with the increase in Cu concentration in the MAO coatings. The corrosion resistance of MAO coatings is also improved slightly.

  1. Preparation and characterization of porous carbon material-coated solid-phase microextraction metal fibers.

    Science.gov (United States)

    Zhu, Fang; Guo, Jiaming; Zeng, Feng; Fu, Ruowen; Wu, Dingcai; Luan, Tiangang; Tong, Yexiang; Lu, Tongbu; Ouyang, Gangfeng

    2010-12-10

    Two kinds of porous carbon materials, including carbon aerogels (CAs), wormhole-like mesoporous carbons (WMCs), were synthesized and used as the coatings of solid-phase microextraction (SPME) fibers. By using stainless steel wire as the supporting core, six types of fibers were prepared with sol-gel method, direct coating method and direct coating plus sol-gel method. Headspace SPME experiments indicated that the extraction efficiencies of the CA fibers are better than those of the WMC fibers, although the surface area of WMCs is much higher than that of CAs. The sol-gel-CA fiber (CA-A) exhibited excellent extraction properties for non-polar compounds (BTEX, benzene, toluene, ethylbenzene, o-xylene), while direct-coated CA fiber (CA-B) presented the best performance in extracting polar compounds (phenols). The two CA fibers showed wide linear ranges, low detection limits (0.008-0.047μgL(-1) for BTEX, 0.15-5.7μgL(-1) for phenols) and good repeatabilities (RSDs less than 4.6% for BTEX, and less than 9.5% for phenols) and satisfying reproducibilities between fibers (RSDs less than 5.2% for BTEX, and less than 9.9% for phenols). These fibers were successfully used for the analysis of water samples from the Pearl River, which demonstrated the applicability of the home-made CA fibers.

  2. Preparation of porous polymer monoliths featuring enhanced surface coverage with gold nanoparticles

    KAUST Repository

    Lv, Yongqin

    2012-10-01

    A new approach to the preparation of porous polymer monoliths with enhanced coverage of pore surface with gold nanoparticles has been developed. First, a generic poly(glycidyl methacrylate-co-ethylene dimethacrylate) monolith was reacted with cystamine followed by the cleavage of its disulfide bonds with tris(2-carboxylethyl)phosphine, which liberated the desired thiol groups. Dispersions of gold nanoparticles with sizes varying from 5 to 40. nm were then pumped through the functionalized monoliths. The materials were then analyzed using both energy dispersive X-ray spectroscopy and thermogravimetric analysis. We found that the quantity of attached gold was dependent on the size of nanoparticles, with the maximum attachment of more than 60. wt% being achieved with 40. nm nanoparticles. Scanning electron micrographs of the cross sections of all the monoliths revealed the formation of a non-aggregated, homogenous monolayer of nanoparticles. The surface of the bound gold was functionalized with 1-octanethiol and 1-octadecanethiol, and these monolithic columns were used successfully for the separations of proteins in reversed phase mode. The best separations were obtained using monoliths modified with 15, 20, and 30. nm nanoparticles since these sizes produced the most dense coverage of pore surface with gold. © 2012 Elsevier B.V.

  3. Waste water purification using new porous ceramics prepared by recycling waste glass and bamboo charcoal

    Science.gov (United States)

    Nishida, Tetsuaki; Morimoto, Akane; Yamamoto, Yoshito; Kubuki, Shiro

    2017-04-01

    New porous ceramics (PC) prepared by recycling waste glass bottle of soft drinks (80 mass%) and bamboo charcoal (20 mass%) without any binder was applied to the waste water purification under aeration at 25 °C. Artificial waste water (15 L) containing 10 mL of milk was examined by combining 15 mL of activated sludge and 750 g of PC. Biochemical oxygen demand (BOD) showed a marked decrease from 178 to 4.0 (±0.1) mg L-1 in 5 days and to 2.0 (±0.1) mg L-1 in 7 days, which was equal to the Environmental Standard for the river water (class A) in Japan. Similarly, chemical oxygen demand (COD) decreased from 158 to 3.6 (±0.1) mg L-1 in 5 days and to 2.2 (±0.1) mg L-1 in 9 days, which was less than the Environmental Standard for the Seawater (class B) in Japan: 3.0 mg L-1. These results prove the high water purification ability of the PC, which will be effectively utilized for the purification of drinking water, fish preserve water, fish farm water, etc.

  4. Preparation of sensitive and recyclable porous Ag/TiO2 composite films for SERS detection

    Science.gov (United States)

    Zhang, Zhengyi; Yu, Jiajie; Yang, Jingying; Lv, Xiang; Wang, Tianhe

    2015-12-01

    Porous Ag/TiO2 composite films were prepared by spin coating of titania on normal glass slides and subsequent photochemical deposition of silver nanoparticles (AgNPs). The films were characterized by XRD and FESEM to reveal micro structural and morphological differences between films obtained under varied conditions. The SERS properties of these films were investigated using aqueous crystal violet (CV) as probe molecules. The results indicate that the content of polyethylene glycol (PEG) and photo-reduction time had significant influences on both the microstructure and SERS performance of Ag/TiO2 films. The highest SERS sensitivity that allowed as low as 10-10 M aqueous CV to be detected, was achieved with the PEG/(C4H9O)4Ti molar ratio being 0.08% and with 30 min of UV irradiation. With this film a linear relationship was established through experiment between SERS intensity and CV concentration from 10-10 to 10-5 M, which could be used as a calibration curve for CV concentration measurement. In addition, the film could be reused as a SERS substrate for up to four times without significantly losing SERS sensitivity if a simple regeneration was followed. It is visualized that the Ag/TiO2 film on glass has potentials for being developed into a practical SERS substrate with high sensitivity and good reusability.

  5. Calcium phosphate/porous silicon biocomposites prepared by cyclic deposition methods: spin coating vs electrochemical activation.

    Science.gov (United States)

    Hernandez-Montelongo, J; Gallach, D; Naveas, N; Torres-Costa, V; Climent-Font, A; García-Ruiz, J P; Manso-Silvan, M

    2014-01-01

    Porous silicon (PSi) provides an excellent platform for bioengineering applications due to its biocompatibility, biodegradability, and bioresorbability. However, to promote its application as bone engineering scaffold, deposition of calcium phosphate (CaP) ceramics in its hydroxyapatite (HAP) phase is in progress. In that sense, this work focuses on the synthesis of CaP/PSi composites by means of two different techniques for CaP deposition on PSi: Cyclic Spin Coating (CSC) and Cyclic Electrochemical Activation (CEA). Both techniques CSC and CEA consisted on alternate Ca and P deposition steps on PSi. Each technique produced specific morphologies and CaP phases using the same independent Ca and P stem-solutions at neutral pH and at room temperature. The brushite (BRU) phase was favored with the CSC technique and the hydroxyapatite (HAP) phase was better synthesized using the CEA technique. Analyses by elastic backscattering spectroscopy (EBS) on CaP/PSi structures synthesized by CEA supported that, by controlling the CEA parameters, an HAP coating with the required Ca/P atomic ratio of 1.67 can be promoted. Biocompatibility was evaluated by bone-derived progenitor cells, which grew onto CaP/PSi prepared by CSC technique with a long-shaped actin cytoskeleton. The density of adhered cells was higher on CaP/PSi prepared by CEA, where cells presented a normal morphological appearance and active mitosis. These results can be used for the design and optimization of CaP/PSi composites with enhanced biocompatibility for bone-tissue engineering.

  6. Calcium phosphate/porous silicon biocomposites prepared by cyclic deposition methods: Spin coating vs electrochemical activation

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Montelongo, J., E-mail: jacobo.hernandez@uam.es [Departamento de Física Aplicada, Universidad Autónoma de Madrid, 28049 Madrid (Spain); Gallach, D.; Naveas, N.; Torres-Costa, V. [Departamento de Física Aplicada, Universidad Autónoma de Madrid, 28049 Madrid (Spain); Climent-Font, A. [Departamento de Física Aplicada, Universidad Autónoma de Madrid, 28049 Madrid (Spain); Centro de Microanálisis de Materiales (CMAM), Universidad Autónoma de Madrid, Madrid 28049 (Spain); García-Ruiz, J.P. [Departamento de Biología Molecular, Universidad Autónoma de Madrid, Cantoblanco, Madrid 28049 (Spain); Manso-Silvan, M. [Departamento de Física Aplicada, Universidad Autónoma de Madrid, 28049 Madrid (Spain)

    2014-01-01

    Porous silicon (PSi) provides an excellent platform for bioengineering applications due to its biocompatibility, biodegradability, and bioresorbability. However, to promote its application as bone engineering scaffold, deposition of calcium phosphate (CaP) ceramics in its hydroxyapatite (HAP) phase is in progress. In that sense, this work focuses on the synthesis of CaP/PSi composites by means of two different techniques for CaP deposition on PSi: Cyclic Spin Coating (CSC) and Cyclic Electrochemical Activation (CEA). Both techniques CSC and CEA consisted on alternate Ca and P deposition steps on PSi. Each technique produced specific morphologies and CaP phases using the same independent Ca and P stem-solutions at neutral pH and at room temperature. The brushite (BRU) phase was favored with the CSC technique and the hydroxyapatite (HAP) phase was better synthesized using the CEA technique. Analyses by elastic backscattering spectroscopy (EBS) on CaP/PSi structures synthesized by CEA supported that, by controlling the CEA parameters, an HAP coating with the required Ca/P atomic ratio of 1.67 can be promoted. Biocompatibility was evaluated by bone-derived progenitor cells, which grew onto CaP/PSi prepared by CSC technique with a long-shaped actin cytoskeleton. The density of adhered cells was higher on CaP/PSi prepared by CEA, where cells presented a normal morphological appearance and active mitosis. These results can be used for the design and optimization of CaP/PSi composites with enhanced biocompatibility for bone-tissue engineering. - Highlights: • Proposed cyclic methods produce specific morphologies and CaP phases in biocomposites. • The brushite phase is favored in the biocomposite produced by Cyclic Spin Coating. • The hydroxyapatite phase is favored in the biocomposite produced by Cyclic Electrochemical Activation. • The Ca/P atomic ratio of hydroxyapatite was validated by elastic backscattering spectroscopy. • Cells grown showed morphological and

  7. Preparation of highly porous gastroretentive metformin tablets using a sublimation method.

    Science.gov (United States)

    Oh, Tack-Oon; Kim, Ju-Young; Ha, Jung-Myung; Chi, Sang-Cheol; Rhee, Yun-Seok; Park, Chun-Woong; Park, Eun-Seok

    2013-04-01

    The present investigation is aimed to formulate floating gastroretentive tablets containing metformin using a sublimation material. In this study, the release of the drug from a matrix tablet was highly dependent on the polymer concentrations. In all formulations, initial rapid drug release was observed, possibly due to the properties of the drug and polymer. The effect of the amount of PEO on swelling and eroding of the tablets was determined. The water-uptake and erosion behavior of the gastroretentive (GR) tablets were highly dependent on the amount of PEO. The water-uptake increased with increasing PEO concentration in the tablet matrix. The weight loss from tablets decreased with increasing amounts of PEO. Camphor was used as the sublimation material to prepare GR tablets that are low-density and easily floatable. Camphor was changed to pores in the tablet during the sublimation process. SEM revealed that the GR tablets have a highly porous morphology. Floating properties of tablets and tablet density were affected by the sublimation of camphor. Prepared floating gastroretentive tablets floated for over 24 h and had no floating lag time. However, as the amount of camphor in the tablet matrix increased, the crushing strength of the tablet decreased after sublimation. Release profiles of the drug from the GR tablets were not affected by tablet density or porosity. In pharmacokinetic studies, the mean plasma concentration of the GR tablets after oral administration was greater than the concentration of glucophase XR. Also, the mean AUC(0-∞) values for the GR tablets were significantly greater than the plasma concentrations of glucophase XR.

  8. Preparation of porous PLA/DBM composite biomaterials and experimental research of repair rabbit radius segmental bone defect.

    Science.gov (United States)

    Zhang, Yumin; Wang, Jianru; Wang, Jue; Niu, Xiaojun; Liu, Jianchun; Gao, Lan; Zhai, Xiaoyan; Chu, Kaibo

    2015-12-01

    Bone substitutes are used in wide range of orthopaedic application. An ideal bone substitute should exhibit superior osteoinductive and osteoconductive properties. Neither bio-derived materials nor synthetic materials can meet the needs of an ideal bone substitute. Preparation of composite materials is a promising way to improve properties of biomaterial. In this study, the porous poly lactic acid (PLA)/demineralized bone matrix (DBM) composite biomaterials prepared by supercritical CO2 technique were implanted to repair rabbit radius segmental bone defect. By comparing with PLA and bone autograft, the X-ray result and histological analysis showed the repair effect of PLA/DBM porous composite materials is significantly better than that of the PLA group and the blank control group, and is similar to autologous bone. The PLA/DBM can promote the healing of bone defects and can be used as a kind of ideal alternative materials to repair bone defects.

  9. Emulsion preparation for novel micro-porous polymeric hemi-shells

    CSIR Research Space (South Africa)

    Naidoo, Kersch

    2008-01-01

    Full Text Available -dichloromethane (DCM) oil phase and emulsification in an acidic polyvinyl alcohol (PVA) aqueous phase, micro-porous hemi-shells formed as solvent evaporated. CO2 gas evolution from the porogen created particles with an externally micro-porous shell and a large internal...

  10. Preparation and mechanical property of a novel 3D porous magnesium scaffold for bone tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xue [Institute of Materials Physics and Chemistry, College of Sciences, Northeastern University, Shenyang 110819 (China); Key Laboratory for Anisotropy and Texture Engineering of Materials, Ministry of Education, Northeastern University, Shenyang 110819 (China); Li, Xiao-Wu, E-mail: xwli@mail.neu.edu.cn [Institute of Materials Physics and Chemistry, College of Sciences, Northeastern University, Shenyang 110819 (China); Key Laboratory for Anisotropy and Texture Engineering of Materials, Ministry of Education, Northeastern University, Shenyang 110819 (China); Li, Ji-Guang; Sun, Xu-Dong [Key Laboratory for Anisotropy and Texture Engineering of Materials, Ministry of Education, Northeastern University, Shenyang 110819 (China)

    2014-09-01

    Porous magnesium has been recently recognized as a biodegradable metal for bone substitute applications. A novel porous Mg scaffold with three-dimensional (3D) interconnected pores and with a porosity of 33–54% was produced by the fiber deposition hot pressing (FDHP) technology. The microstructure and morphologies of the porous Mg scaffold were characterized by scanning electron microscopy (SEM), and the effects of porosities on the microstructure and mechanical properties of the porous Mg were investigated. Experimental results indicate that the measured Young's modulus and compressive strength of the Mg scaffold are ranged in 0.10–0.37 GPa, and 11.1–30.3 MPa, respectively, which are fairly comparable to those of cancellous bone. Such a porous Mg scaffold having a 3D interconnected network structure has the potential to be used in bone tissue engineering. - Highlights: • A novel porous Mg was produced by a fiber deposition hot pressing technology. • The porous Mg has a 3D interconnected network structure with a porosity of 33-54%. • Mechanical properties of the porous Mg are comparable to those of cancellous bone.

  11. Preparation and mechanical property of a novel 3D porous magnesium scaffold for bone tissue engineering.

    Science.gov (United States)

    Zhang, Xue; Li, Xiao-Wu; Li, Ji-Guang; Sun, Xu-Dong

    2014-09-01

    Porous magnesium has been recently recognized as a biodegradable metal for bone substitute applications. A novel porous Mg scaffold with three-dimensional (3D) interconnected pores and with a porosity of 33-54% was produced by the fiber deposition hot pressing (FDHP) technology. The microstructure and morphologies of the porous Mg scaffold were characterized by scanning electron microscopy (SEM), and the effects of porosities on the microstructure and mechanical properties of the porous Mg were investigated. Experimental results indicate that the measured Young's modulus and compressive strength of the Mg scaffold are ranged in 0.10-0.37 GPa, and 11.1-30.3 MPa, respectively, which are fairly comparable to those of cancellous bone. Such a porous Mg scaffold having a 3D interconnected network structure has the potential to be used in bone tissue engineering.

  12. Selective, ultrathin membrane skins prepared by deposition of novel polymer films on porous alumina supports

    Science.gov (United States)

    Balachandra, Anagi Manjula

    Membrane-based separations are attractive in industrial processes because of their low energy costs and simple operation. However, low permeabilities often make membrane processes uneconomical. Since flux is inversely proportional to membrane thickness, composite membranes consisting of ultrathin, selective skins on highly permeable supports are required to simultaneously achieve high throughput and high selectivity. However, the synthesis of defect-free skins with thicknesses less than 50 nm is difficult, and thus flux is often limited. Layer-by-layer deposition of oppositely charged polyelectrolytes on porous supports is an attractive method to synthesize ultrathin ion-separation membranes with high flux and high selectivity. The ion-transport selectivity of multilayer polyelectrolyte membranes (MPMs) is primarily due to Donnan exclusion; therefore increase in fixed charge density should yield high selectivity. However, control over charge density in MPMs is difficult because charges on polycations are electrostatically compensated by charges on polyanions, and the net charge in the bulk of these films is small. To overcome this problem, we introduced a templating method to create ion-exchange sites in the bulk of the membrane. This strategy involves alternating deposition of a Cu2+-poly(acrylic acid) complex and poly(allylamine hydrochloride) on a porous alumina support followed by removal of Cu2+ and deprotonation to yield free -COO- ion-exchange sites. Diffusion dialysis studies showed that the Cl-/SO42-. Selectivity of Cu2+-templated membranes is 4-fold higher than that of membranes prepared in the absence of Cu2+. Post-deposition cross-linking of these membranes by heat-induced amide bond formation further increased Cl-/SO42- selectivity to values as high as 600. Room-temperature, surface-initiated atom transfer radical polymerization (ATRP) provides another convenient method for formation of ultrathin polymer skins. This process involves attachment of

  13. Rough SERS substrate based on gold coated porous silicon layer prepared on the silicon backside surface

    Science.gov (United States)

    Dridi, H.; Haji, L.; Moadhen, A.

    2017-04-01

    We report in this paper a novel method to elaborate rough Surface Enhanced Raman Scattering (SERS) substrate. A single layer of porous silicon was formed on the silicon backside surface. Morphological characteristics of the porous silicon layer before and after gold deposition were influenced by the rough character (gold size). The reflectance measurements showed a dependence of the gold nano-grains size on the surface nature, through the Localized Surface Plasmon (LSP) band properties. SERS signal of Rhodamine 6G used as a model analyte, adsorbed on the rough porous silicon layer revealed a marked enhancement of its vibrational modes intensities.

  14. Preparation of porous Al2O3-Ti-C perform by combustion synthesis

    Directory of Open Access Journals (Sweden)

    K.Granat

    2009-04-01

    Full Text Available Using combustion synthesis porous ceramic preforms for composite reinforcing were produced. Prepared mixture of alumina Saffilfibres, Ti powder and graphite flakes, after drying were placed in waveguide of microwave reactor. Supplied with constant power of 540Wmagnetron ignited and maintained reaction in flowing stream of CO2 gas. Al2O3 fibres should improve preliminary endurance of perform,whereas Ti powder processed to hard titanium carbides and oxides. During microwave heating ignited plasma additionally improveprocess and partly fused metallic Ti. Recorded temperature curves were similar for various samples. The highest synthesis temperature revealed samples containing 10% of Al2O3 , 10% of Ti and 5% of graphite, all percentages atomic. Microscopic observation showed considerable microstructure inhomogeneity of some samples. Both irregular component ordering and partly processed Ti particles inside preform exclude them for subsequent infiltration. Chemical analyze EDS of Ti based compounds partly confirmed work purpose, evidencing presence of Ti oxides and carbides. Independently of graphite content these compounds formed folded strips around solid or empty volume. Depends on CO2 availability, reaction could be slowed down resulting in more compacted Ti compounds. Created as a result of combustion synthesis Ti compound after infiltration with liquid metal properly bounded with the matrix. It could be assumed that redox reaction proceeded and on surface of Ti compound alumina and Al-Ti compounds were created. The preforms of proper strength and homogeneous structure were infiltrated with AlSi7Mg by squeeze casting method. In relation to typical composite reinforced only with fibres no significant increase of defects quantity was observed. Preliminary examination of mechanical properties confirmed that assumed work purpose is reasonable.

  15. Preparation of porous chitosan-poly(acrylic acid)-calcium phosphate hybrid nanoparticles via mineralization

    Institute of Scientific and Technical Information of China (English)

    CHEN ChangJing; DENG Yu; YAN ErYun; HU Yong; JIANG XiQun

    2009-01-01

    In this work,the preparation of chitosan-poly(acrylic acid)-calcium phosphate hybrid nanoparticles (CS-PAA-CaP NP) based on the mineralization of calcium phosphate (CAP) on the surface of chitosan-poly (acrylic acid) nanoparticles (CS-PAA NPs) was reported. CS-PAA-CaP NPs were achieved by directly adding ammonia to the aqueous solution of CS-PAA nanoparticles or by thermal decomposition of urea in the aqueous solution of CS-PAA nanoparticles,resulting in the mineralization of CaP on the surface of CS-PAA NPs. Through these two routes,especially using urea as a pH-regulator,the precipitation of CS-PAA NPs,a common occurrence in basic environment,was avoided. The size,morphology and ingredient of CS-PAA-CaP hybrid nanoparticles were characterized by dynamic light scattering (DLS),transmission electron microscope (TEM),scanning electron microscope (SEM),thermogravimetry analysis (TGA) and X-ray diffractometer (XRD). When urea was used as the pH regulator to facilitate the mineralization during the thermal urea decomposition procedure,regular CS-PAA-CaP hybrid nanoparticles with a porosity-structural CaP shells and 400-600 nm size were obtained. TGA result revealed that the hybrid NPs contained approximately 23% inorganic component,which was consistent with the ratio of starting materials. The XRD spectra of hybrid nanoparticles indicated that dicalcium phosphate (DCP:CaHPO4) crystal was a dominant component of mineralization.The porous structure of the CS-PAA-CaP hybrid NPs might be greatly useful in pharmaceutical and other medical applications.

  16. On the preparation of fine V8 C7-WC and V4 C 3-WC powders

    CSIR Research Space (South Africa)

    Osborne, C

    1997-01-01

    Full Text Available The aim of this work was to produce V8 C7-WC and V4 C 3-WC powders with grain size between 1 and 2mu-m, as a first stage of the preparation of fine grained WC-VC-Co hardmetal. V8 C7-WC powder was produced via two routes: starting from preformed V8 C7...

  17. Fine-Needle Aspiration, Touch Imprint, and Crush Preparation Cytology for Diagnosing Thyroid Malignancies in Thyroid Nodules

    OpenAIRE

    Ahmadinejad, Mojtaba; Aliepour, Asghar; Anbari, Khatereh; Kaviani, Mojhgan; Ganjizadeh, Hasan; Nadri, Sedigheh; Foroutani, Niloufar; Meysami, Masoumeh; Almasi, Vahid

    2013-01-01

    Several methods are used to evaluate the thyroid nodules. The aim of this study was to determine the sensitivity, specificity, false positive and negative rates, positive predictive value (PPV), and negative predictive value (NPV) of touch imprint, crush preparation, and fine-needle aspiration (FNA) methods. This cross-sectional study was done in Shohada-ye Ashayer University Hospital in Khorramabad. All the patients who underwent thyroid surgery due to thyroid nodules in this hospital betwee...

  18. THE USE OF A NOVEL ALDEHYDE-FUNCTIONALIZED CHITOSAN HYDROGEL TO PREPARE POROUS TUBULAR SCAFFOLDS FOR VASCULAR TISSUE ENGINEERING APPLICATIONS

    Directory of Open Access Journals (Sweden)

    Eduardo P. Azevedo

    Full Text Available In this work, porous tubular scaffolds were prepared from a novel water soluble aldehyde-functionalized chitosan (ALDCHIT hydrogel, which was obtained by dissolving this chitosan derivative in water and using oxidized dextrose (OXDEXT as the crosslinking agent at different ALDCHIT:OXDEXT mole ratios (10:1, 10:2 and 10:4. By increasing the amount of OXDEXT in respect to ALDCHIT the hydrogels became more rigid and could absorb more than 200% of its weight in water. Since the ALDCHIT:OXDEXT 10:4 was the most stable hydrogel, its ability to form porous tubular scaffolds was investigated. The tubular scaffolds were prepared by the lyophilization method, where the orientation of the pores was controlled by exposing either the internal or the external surface of the frozen hydrogel during the sublimation step. When only the inner surface of the frozen hydrogel was exposed, tubular scaffolds with a highly porous lumen and a sealed outer surface were obtained, where the orientation of the pores, their sizes and interconnectivity seem to be optimum for vascular tissue engineering application.

  19. Thermo-stabilized, porous polyimide microspheres prepared from nanosized SiO2 templating via in situ polymerization

    Directory of Open Access Journals (Sweden)

    M. Q. Liu

    2015-01-01

    Full Text Available In this article, we addressed a feasible and versatile method of the fabrication of porous polyimide microspheres presenting excellent heat resistance. The preparation process consisted of two steps. Firstly, a novel polyimide/nano-silica composite microsphere was prepared via the self-assembly structures of poly(amic acid (PAA, precursor of PI/nanosized SiO2 blends after in situ polymerization, following the two-steps imidization. Subsequently, the encapsulated nanoparticles were etched away by hydrofluoric acid treatment, giving rise to the pores. It is found the composite structure of PI/SiO2 is a precondition of the formation of nanoporous structures, furthermore, the morphology of the resultant pore could be relatively tuned by changing the content and initial morphology of silica nano-particles trapped into PI matrix. The thermal properties of the synthesized PI porous spheres were studied, indicating that the introduction of nanopores could not effectively influence the thermal stabilities of PI microspheres. Moreover, the fabrication technique described here may be extended to other porous polymer systems.

  20. Preparation of a Titania/X-Zeolite/Porous Glass Composite Photocatalyst Using Hydrothermal and Drop Coating Processes

    Directory of Open Access Journals (Sweden)

    Atsuo Yasumori

    2015-01-01

    Full Text Available Combinations of TiO2 photocatalysts and various adsorbents have been widely studied for the adsorption and photocatalytic decomposition of gaseous pollutants such as volatile organic compounds (VOCs. Herein, a TiO2-zeolite-porous glass composite was prepared using melt-quenching and partial sintering, hydrothermal treatment, and drop coating for preparation of the porous glass support and X-zeolite and their combination with TiO2, respectively. The obtained composite comprised anatase phase TiO2, X-zeolite, and the porous glass support, which were combined at the micro to nanometer scales. The composite had a relatively high specific surface area of approximately 25 m2/g and exhibited a good adsorption capacity for 2-propanol. These data indicated that utilization of this particular phase-separated glass as the support was appropriate for the formation of the bulk photocatalyst-adsorbent composite. Importantly, the photocatalytic decomposition of adsorbed 2-propanol proceeded under UV light irradiation. The 2-propanol was oxidized to acetone and then trapped by the X-zeolite rather than being released to the atmosphere. Consequently, it was demonstrated that the micrometer-scaled combination of TiO2 and zeolite in the bulk form is very useful for achieving both the removal of gaseous organic pollutants and decreasing the emission of harmful intermediates.

  1. Micro- and nano-porous surface patterns prepared by surface-confined directional melt crystallization of solvent

    Science.gov (United States)

    Kim, Byoung Soo; Kim, Hyun Jin; An, Suyeong; Chi, Sangwon; Kim, Junseok; Lee, Jonghwi

    2017-07-01

    Recently, numerous attempts have been made to engineer micro- and nano-porous surface patterns or to develop convenient preparation methods for the practical applications of self-cleaning surfaces, water-repellent surfaces, novel textures, etc. Herein, we introduce a simple, cheap, and repeatable crystallization-based method to produce porous surface structures, on any surface of already fabricated polymeric materials. Contact of the solvent phase with cooled polymer surfaces enabled the limited dissolution of the surfaces and the subsequent extremely fast melt crystallization of the solvent. After removing the crystals, various micro- and nano-porous patterns were obtained, whose pore sizes ranged over three orders of magnitude. Pore depth was linearly dependent on the dissolution time. Crystal growth was mainly directed normal to the surfaces, but it was also controlled in-plane, resulting in cylindrical or lamellar structures. Superhydrophobic surfaces were successfully prepared on both polystyrene and polycarbonate. This process offers a novel surface engineering tool for a variety of polymer surfaces, whose topology can be conveniently controlled over a wide range by crystal engineering.

  2. Apparent Electrical Conductivity of Porous Titanium Prepared by the Powder Metallurgy Method

    Institute of Scientific and Technical Information of China (English)

    LI Cheng-Feng; ZHU Zhen-Gang

    2005-01-01

    @@ Porous titanium is produced by the powder metallurgy method. Dependence of the electrical conductivity on the porosity and pore size is investigated and the experimental results are compared with a number of models. It is found that the minimum solid area model could be successfully applied to describe the relationship between the electrical conductivity and the porosity of porous titanium. This kind of conductivity increases with increasing pore sizes.

  3. Preparation of UO_2 Fine Particle by Hydrolysis of Uranium(IV) Alkoxide

    OpenAIRE

    Satoh, Isamu; Takahashi, Mitsuyuki; Miura, Shigeyuki

    1997-01-01

    Fine particles of uranium(IV) dioxides were obtained by hydrolysis of uranium(IV) ethoxide which was synthesized by reacting uranium tetrachloride with sodium ethoxide. The monodispersed submicrometer particles were confirmed by SEM observation.

  4. Luminescence evolution of porous GaN thin films prepared via UV-assisted electrochemical etching

    Energy Technology Data Exchange (ETDEWEB)

    Cheah, S.F., E-mail: sookfongcheah@yahoo.com [Nano-Optoelectronic Research and Technology Laboratory, School of Physics, Universiti Sains Malaysia, 11800 Penang (Malaysia); Lee, S.C. [Nano-Optoelectronic Research and Technology Laboratory, School of Physics, Universiti Sains Malaysia, 11800 Penang (Malaysia); Department of Physics, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Ng, S.S.; Yam, F.K.; Abu Hassan, H.; Hassan, Z. [Nano-Optoelectronic Research and Technology Laboratory, School of Physics, Universiti Sains Malaysia, 11800 Penang (Malaysia)

    2015-03-15

    Porous gallium nitride (GaN) thin films with different surface morphologies and free carriers properties were fabricated from Si-doped GaN thin films using ultra-violet assisted electrochemical etching approach under various etching voltages. Fluctuation of luminescence signals was observed in the photoluminescence spectra of porous GaN thin films. Taking advantage of the spectral sensitivity of infrared attenuated total reflection spectroscopy on semiconductor materials, roles of free carriers and porous structure in controlling luminescence properties of GaN were investigated thoroughly. The results revealed that enhancement in luminescence signal is not always attained upon porosification. Although porosification is correlated to the luminescence enhancement, however, free carrier is the primary factor to enhance luminescence intensity. Due to unavoidable significant reduction of free carriers from Si-doped GaN in the porosification process, control of etching depth (i.e., thickness of porous layer formed from the Si-doped layer) is critical in fabricating porous GaN thin film with enhanced luminescence response. - Highlights: • Various pore morphologies with free carrier properties are produced by Si-doped GaN. • Free carriers are important to control the luminescence signal of porous GaN. • Enhancement of luminescence signal relies on the pore depth of Si-doped layer.

  5. Porous bioceramic bead prepared by calcium phosphate with sodium alginate gel and PE powder

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Y.C. [Department of Orthopaedic Surgery, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan (China); Ho, M.L.; Wu, S.C. [Department of Physiology, Kaohsiung Medical University, 100, Shih-Chuan 1st Rd, Kaohsiung 807, Taiwan (China); Hsieh, H.S. [Faculty of Medicinal and Applied Chemistry, Kaohsiung Medical University, 100, Shih-Chuan 1st Rd, Kaohsiung 807, Taiwan (China); Wang, C.K. [Faculty of Medicinal and Applied Chemistry, Kaohsiung Medical University, 100, Shih-Chuan 1st Rd, Kaohsiung 807, Taiwan (China)], E-mail: ckwang@kmu.edu.tw

    2008-08-01

    The porous calcium phosphate beads were made by an alginate-interacting Ca ions mechanism on addition of a pore-forming polyethylene (PE) powder at 1250 deg. C sintering. The nature of the powders and porous beads were analyzed through X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR) and heavy metal analysis by inductively coupled plasma-optical emission spectroscopy (ICP-OES). The porous beads size and the pore microstructure characteristics were determined using scanning electron microscopy (SEM). Beside, the porosity analysis was evaluated out using an Archimedes' principle and mercury porosimetry. Then, the sodium ampicillin was penetrated/adsorbed onto calcium-deficient hydroxyapatite porous beads, and was subsequently released in PBS. No matter whether the raw material was HAp, TCP or biphase, the Ca{sub 9}(HPO{sub 4})(PO{sub 4}){sub 5}OH phase (CDHA) was formed only after sintering. Porous beads of various calcium phosphates with different sizes (0.9-1.1 mm) and pore size groups (60-120 {mu}m and lower than 10 {mu}m) were appeared. The release kinetics of sodium ampicillin from these porous beads have indicated the possibility of using these materials as possible carriers for drug delivery.

  6. Preparation and characterization of magnetic porous carbon microspheres for removal of methylene blue by a heterogeneous Fenton reaction.

    Science.gov (United States)

    Zhou, Lincheng; Shao, Yanming; Liu, Junrui; Ye, Zhengfang; Zhang, He; Ma, Junjun; Jia, Yan; Gao, Weijie; Li, Yanfeng

    2014-05-28

    High-specific-surface-area magnetic porous carbon microspheres (MPCMSs) were fabricated by annealing Fe(2+)-treated porous polystyrene (PS) microspheres, which were prepared using a two-step seed emulsion polymerization process. The resulting porous microspheres were then sulfonated, and Fe(2+) was loaded by ion exchange, followed by annealing at 250 °C for 1 h under an ambient atmosphere to obtain the PS-250 composite. The MPCMS-500 and MPCMS-800 composites were obtained by annealing PS-250 at 500 and 800 °C for 1 h, respectively. The iron oxide in MPCMS-500 mainly existed in the form of Fe3O4, which was concluded by characterization. The MPCMS-500 carbon microspheres were used as catalysts in heterogeneous Fenton reactions to remove methylene blue (MB) from wastewater with the help of H2O2 and NH2OH. The results indicated that this catalytic system has a good performance in terms of removal of MB; it could remove 40 mg L(-1) of MB within 40 min. After the reaction, the catalyst was conveniently separated from the media within several seconds using an external magnetic field, and the catalytic activity was still viable even after 10 removal cycles. The good catalytic performance of the composites could be attributed to synergy between the functions of the porous carbon support and the Fe3O4 nanoparticles embedded in the carrier. This work indicates that porous carbon spheres provide good support for the development of a highly efficient heterogeneous Fenton catalyst useful for environmental pollution cleanup.

  7. Preparation of a porous clay heterostructure and study of its adsorption capacity of phenol and chlorinated phenols from aqueous solutions.

    Science.gov (United States)

    Arellano-Cárdenas, Sofía; Gallardo-Velázquez, Tzayhrí; Osorio-Revilla, Guillermo; López-Cortez, Ma del Socorro

    2008-01-01

    A porous clay heterostructure (PCH) from a Mexican clay was prepared and characterized, and its aqueous phenol and dichlorophenols (DCPs) adsorption capacities were studied using a batch equilibrium technique. The PCH displayed a surface area of 305.5 m2/g, 37.2 A average porous diameter, and a basal space of 23.2 A. The adsorption capacity shown by the PCH for both phenol and DCPs from water (14.5 mg/g for phenol; 48.7 mg/g for 3,4-DCP; and 45.5 mg/g for 2,5-DCP) suggests that the PCH has both hydrophobic and hydrophilic characteristics, as a result of the presence of silanol and siloxane groups formed during the pillaring and calcination of the PCH. The values of maximal adsorption capacity for dichlorophenols were higher than those reported for aluminum pillared clays and some inorgano-organo clays and comparable with some ionic exchange resins.

  8. Effect of particle size on microstructure and strength of porous spinel ceramics prepared by pore-forming in situ technique

    Indian Academy of Sciences (India)

    Wen Yan; Nan Li; Yuanyuan Li; Guangping Liu; Bingqiang Han; Juliang Xu

    2011-08-01

    The porous spinel ceramics were prepared from magnesite and bauxite by the pore-forming in situ technique. The characterization of porous spinel ceramics was determined by X-ray diffractometer (XRD), scanning electron microscopy(SEM), mercury porosimetry measurement etc and the effects of particle size on microstructure and strength were investigated. It was found that particle size affects strongly on the microstructure and strength. With decreasing particle size, the pore size distribution occurs from multi-peak mode to bi-peak mode, and lastly to mono-peak mode; the porosity decreases but strength increases. The most apposite mode is the specimens from the grinded powder with a particle size of 6.53 m, which has a high apparent porosity (40%), a high compressive strength (75.6MPa), a small average pore size (2.53 m) and a homogeneous pore size distribution.

  9. Porous poly(D,L-lactic acid) foams with tunable structure and mechanical anisotropy prepared by supercritical carbon dioxide.

    Science.gov (United States)

    Floren, Michael; Spilimbergo, Sara; Motta, Antonella; Migliaresi, Claudio

    2011-11-01

    The design and tunability of tissue scaffolds, such as pore size and geometry, is crucial to the success of an engineered tissue replacement. Moreover, the mechanical nature of a tissue scaffold should display properties similar to the tissue of interest; therefore, tunability of the foam mechanical properties is desirable. Polymeric foams prepared using supercritical carbon dioxide as a blowing agent has emerged in recent years as a promising technique to prepare porous scaffolds. While a number of groups have reported on the tailoring of scaffold morphologies by using gas foaming techniques, few have considered the effects of such processing conditions on the physical and mechanical anisotropy achieved. The aim of this study was to demonstrate the tunability of the structure and mechanical anisotropy of foams prepared using a variety of different gas foaming conditions. Porous poly(D,L lactic acid) foams were prepared by the systematic adjustment of processing conditions, namely pressure, temperature and venting time, resulting in an extensive range of scaffold morphologies. Characterization of sample anisotropy was achieved by mechanical evaluation of foam specimens both longitudinal and transverse to the foaming direction. The obtained mechanical properties demonstrated a strong dependence of the processing conditions on mechanical anisotropy and performance. Furthermore, results indicate that factors other than pore geometry may be necessary to define the mechanical behavior of the foam specimens. The favorable compressive moduli, coupled with large degrees of anisotropy, suggests these foams may have suitable application as scaffolds for bone tissue engineering.

  10. Preparation and characterization of monodisperse large-porous silica microspheres as the matrix for protein separation.

    Science.gov (United States)

    Xia, Hongjun; Wan, Guangping; Zhao, Junlong; Liu, Jiawei; Bai, Quan

    2016-11-04

    High performance liquid chromatography (HPLC) is a kind of efficient separation technology and has been used widely in many fields. Micro-sized porous silica microspheres as the most popular matrix have been used for fast separation and analysis in HPLC. In this paper, the monodisperse large-porous silica microspheres with controllable size and structure were successfully synthesized with polymer microspheres as the templates and characterized. First, the poly(glycidyl methacrylate-co-ethyleneglycol dimethacrylate) microspheres (PGMA-EDMA) were functionalized with tetraethylenepentamine (TEPA) to generate amino groups which act as a catalyst in hydrolysis of tetraethyl orthosilicate (TEOS) to form Si-containing low molecular weight species. Then the low molecular weight species diffused into the functionalized PGMA-EDMA microspheres by induction force of the amino groups to form polymer/silica hybrid microspheres. Finally, the organic polymer templates were removed by calcination, and the large-porous silica microspheres were obtained. The compositions, morphology, size distribution, specific surface area and pore size distribution of the porous silica microspheres were characterized by infrared analyzer, scanning-electron microscopy, dynamic laser scattering, the mercury intrusion method and thermal gravimetric analysis, respectively. The results show that the agglomeration of the hybrid microspheres can be overcome when the templates were functionalized with TEPA as amination reagent, and the yield of 95.7% of the monodisperse large-porous silica microspheres can be achieved with high concentration of polymer templates. The resulting large-porous silica microspheres were modified with octadecyltrichlorosilane (ODS) and the chromatographic evaluation was performed by separating the proteins and the digest of BSA. The baseline separation of seven kinds of protein standards was achieved, and the column delivered a better performance when separating BSA digests

  11. Preparation and characterization of biomedical highly porous Ti-Nb alloy.

    Science.gov (United States)

    Ruan, Jianming; Yang, Hailin; Weng, Xiaojun; Miao, Jinglei; Zhou, Kechao

    2016-04-01

    The compressive strength and the biocompatibility were assessed for the porous Ti-25 wt%Nb alloy fabricated by the combination of the sponge impregnation technique and sintering technique. The alloy provided pore sizes of 300-600 μm, porosity levels of 71 ± 1.5%, in which the volume fraction of open pores was 94 ± 1.3%. The measurements also showed that the alloy had the compressive Young's modulus of 2.23 ± 0.5 GPa and the strength of 98.4 ± 4.5 MPa, indicating that the mechanical properties of the alloy are similar to those of human bone. The scanning electron microscopy (SEM) observations revealed that the pores were well connected to form three-dimension (3D) network open cell structure. Moreover, no obvious impurities were detected in the porous structure. The experiments also confirmed that rabbit bone mesenchymal stem cells (MSCs) could adhere and proliferate in the porous Ti-25 wt%Nb alloy. The interactions between the porous alloy and the cells are attributed to the porous structure with relatively higher surface. The suitable mechanical and biocompatible properties confirmed that this material has a promising potential in the application for tissue engineering.

  12. Preparation of self-organized porous tungsten oxide using HFCVD technique

    Energy Technology Data Exchange (ETDEWEB)

    Chavez, Fernando [Departamento de Fisicoquimica de Materiales, ICUAP, Benemerita Universidad Autonoma de Puebla, Puebla, 72000 (Mexico); Felipe, Carlos, E-mail: cfelipe98@gmail.com [Departamento de Fisicoquimica de Materiales, ICUAP, Benemerita Universidad Autonoma de Puebla, Puebla, 72000 (Mexico); Departamento de Biociencias e Ingenieria, CIIEMAD, Instituto Politecnico Nacional, Mexico D.F., 07340 (Mexico); Lima, Enrique [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Circuito Exterior, Ciudad Universitaria, Mexico D.F., 04510 (Mexico); Lara, Victor [Departamento de Quimica, Universidad Autonoma Metropolitana, Iztapalapa, Mexico D.F., 09340 (Mexico); Angeles-Chavez, Carlos [Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Mexico D.F., 07730 (Mexico); Hernandez, Miguel A. [Departamento de Investigacion en Zeolitas, ICUAP, Benemerita Universidad Autonoma de Puebla, Puebla, 72000 (Mexico)

    2010-03-15

    Hot filament chemical vapour deposition (HFCVD) technique was applied to deposit a porous tungsten oxide film on glass wafers. The tungsten filament was used as a source in a vacuum atmosphere. The porous film was characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray thermodiffraction, nitrogen sorption and small-angle X-ray scattering. From these characterization techniques it was found that porous film presents a clusters-like morphology of WO{sub 3-x} particles. The particles are arranged on substrate in a way that free spaces are originated, as a 3D network of pores. By increasing temperature, the BET specific surface area of the porous film changes from 38.67 to 34.5 m{sup 2} g{sup -1} most likely due to the particles have a tendency to stick together to form aggregates, particularly at high temperature. A fractal geometry approach permits to elucidate the interconnection between the particles and a simple model of the porous structure is proposed.

  13. Preparation and evaluation of highly drug-loaded fine globular granules using a multi-functional rotor processor.

    Science.gov (United States)

    Iwao, Yasunori; Kimura, Shin-Ichiro; Ishida, Masayuki; Mise, Ryohei; Yamada, Masaki; Namiki, Noriyuki; Noguchi, Shuji; Itai, Shigeru

    2015-01-01

    The manufacture of highly drug-loaded fine globular granules eventually applied for orally disintegrating tablets has been investigated using a unique multi-functional rotor processor with acetaminophen, which was used as a model drug substance. Experimental design and statistical analysis were used to evaluate potential relationships between three key operating parameters (i.e., the binder flow rate, atomization pressure and rotating speed) and a series of associated micromeritics (i.e., granule mean size, proportion of fine particles (106-212 µm), flowability, roundness and water content). The results of multiple linear regression analysis revealed several trends, including (1) the binder flow rate and atomization pressure had significant positive and negative effects on the granule mean size value, Carr's flowability index, granular roundness and water content, respectively; (2) the proportion of fine particles was positively affected by the product of interaction between the binder flow rate and atomization pressure; and (3) the granular roundness was negatively and positively affected by the product of interactions between the binder flow rate and the atomization pressure, and the binder flow rate and rotating speed, respectively. The results of this study led to the identification of optimal operating conditions for the preparation of granules, and could therefore be used to provide important information for the development of processes for the manufacture of highly drug-loaded fine globular granules.

  14. Additive manufacturing technologies of porous metal implants

    Directory of Open Access Journals (Sweden)

    Yang Quanzhan

    2014-06-01

    Full Text Available Biomedical metal materials with good corrosion resistance and mechanical properties are widely used in orthopedic surgery and dental implant materials, but they can easily cause stress shielding due to the significant difference in elastic modulus between the implant and human bones. The elastic modulus of porous metals is lower than that of dense metals. Therefore, it is possible to adjust the pore parameters to make the elastic modulus of porous metals match or be comparable with that of the bone tissue. At the same time, the open porous metals with pores connected to each other could provide the structural condition for bone ingrowth, which is helpful in strengthening the biological combination of bone tissue with the implants. Therefore, the preparation technologies of porous metal implants and related research have been drawing more and more attention due to the excellent features of porous metals. Selective laser melting (SLM and electron beam melting technology (EBM are important research fields of additive manufacturing. They have the advantages of directly forming arbitrarily complex shaped metal parts which are suitable for the preparation of porous metal implants with complex shape and fine structure. As new manufacturing technologies, the applications of SLM and EBM for porous metal implants have just begun. This paper aims to understand the technology status of SLM and EBM, the research progress of porous metal implants preparation by using SLM and EBM, and the biological compatibility of the materials, individual design and manufacturing requirements. The existing problems and future research directions for porous metal implants prepared by SLM and EBM methods are discussed in the last paragraph.

  15. Preparation and characterization of poly(D,L-lactide) and its porous biomaterials

    Institute of Scientific and Technical Information of China (English)

    ZHOU Zhong-cheng; RUAN Jian-ming; HUANG Bai-yun; LI Ya-jun; ZOU Jian-peng; ZHANG Hai-bo

    2005-01-01

    Poly(D,L-lactide) was synthesized by indirect method from D,L-lactic acid and characterized by infrared spectrum and proton nuclear magnetic resonance. The influences of monomer purity, initiator concentration, polymerization temperature and polymerization time on the relative molecular mass of poly(D, L-lactide) were investigated. The polylactide was made into porous materials by using solvent-casting particulate-leaching method. Under the optimized conditions, polylactides with a viscosity average molecular mass up to 1.82×105 are obtained and the results are fairly reproducible. Scanning electron microscope observation indicates that the sample is highly porous and well-distributed with good interconnections between pores and the pore size of porous materials is in the range from 200 μm to 500 μm and it can be used as scaffold for bone tissue engineering.

  16. Preparation and characterization of porous titanium using space-holder technique

    Institute of Scientific and Technical Information of China (English)

    NIU Wenjuan; BAI Chenguang; QIU Guibao; WANG Qiang; WEN Liangying; CHEN Dengfu; DONG Lingyan

    2009-01-01

    Titanium-based porous materials can be used in structural applications and medical implants because of their excellent mechanical properties at elevated temperatures, good corrosion resistance and wonderful biocompatibility. However, most of the methods used to produce the po-rous metal can only give limited porosity and uncontrollable pore morphologies. In the present study, a newly developed method of powder metallurgy using the space-holder technique was used to fabricate porous titanium with controllable porosity. The morphological features and mechanical properties of the products were fully investigated. The results show that the porosity is in the range of 55%-75%, and the mean pore size, with an average sphericity of~0.72, is 600 μm The plateau stresses vary between 10 MPa and 35 MPa. As predicted by the Gibson-Ashby model, the plateau stress decreases with increasing porosity.

  17. Fine-sized LiNi 0.8Co 0.15Mn 0.05O 2 cathode powders prepared by combined process of gas-phase reaction and solid-state reaction methods

    Science.gov (United States)

    Ju, Seo Hee; Kang, Yun Chan

    The Ni-rich precursor powders with spherical shape and filled morphologies were prepared by spray pyrolysis from the spray solution with citric acid, ethylene glycol and a drying control chemical additive. The precursor powders with controlled morphologies formed the LiNi 0.8Co 0.15Mn 0.05O 2 cathode powders with spherical shape and fine size by solid-state reaction with lithium hydroxide. However, the cathode powders prepared from the spray solution without additives had irregular morphologies and were large in size. The precursor powders with hollow and porous morphologies formed cathode powders with irregular and aggregated morphologies. The composition ratios of the nickel, cobalt and manganese components were maintained in the as-prepared, precursor and cathode powders. The initial discharge capacity of the LiNi 0.8Co 0.15Mn 0.05O 2 cathode powders with spherical shape and fine size tested at a temperature of 55 °C under a constant current density of 0.5 C was 215 mAh g -1. The discharge capacity of the LiNi 0.8Co 0.15Mn 0.05O 2 cathode powders decreased to 81% of the initial value after 30 cycles.

  18. Structural, optical and magnetic properties of porous alpha-Fe2O3 nanostructures prepared by rapid combustion method.

    Science.gov (United States)

    Manikandan, A; Vijaya, J Judith; Kennedy, L John

    2013-04-01

    Porous iron oxide (alpha-Fe2O3) nanoparticles were synthesized by the microwave combustion method (MCM) using urea as the fuel. For the purpose of comparison, it was also prepared using the conventional combustion method (CCM). The as-synthesized porous alpha-Fe2O3 nanoparticles were characterized by X-ray powder diffraction (XRD), high resolution scanning electron microscopy (HR-SEM), high resolution transmission electron microscopy (HR-TEM), energy dispersive X-ray analysis (EDX), diffuse reflectance spectroscopy (DRS), Brunauer-Emmett-Teller (BET) analysis and vibrating sample magnetometer (VSM) analysis. The XRD results confirmed the formation of rhombohedral alpha-Fe2O3 phase. The formation of alpha-Fe2O3 nanoparticles was confirmed by HR-SEM and HR-TEM, and their possible formation mechanisms were also proposed. The optical absorption and the band gap were determined by DRS spectra. The surface area was derived from the nitrogen adsorption-desorption isotherms using BET analysis. The magnetic properties of the synthesized alpha-Fe2O3 were investigated with vibrating sample magnetometer (VSM) and their hysteresis loops were obtained. Both the prepared samples show ferromagnetic behavior with hysteresis curve at room temperature. The relatively high saturation magnetization (65.23 emu/g) of alpha-Fe2O3-MCM suggests that this method is suitable for preparing high-quality nanocrystalline magnetic alpha-Fe2O3 for practical applications.

  19. Hexagonal ZnO porous plates prepared from microwave synthesized layered zinc hydroxide sulphate via thermal decomposition

    Energy Technology Data Exchange (ETDEWEB)

    Machovsky, Michal, E-mail: machovsky@ft.utb.cz [Centre of Polymer Systems, University Institute, Tomas Bata University in Zlin, Nad Ovcirnou 3685, 760 01 Zlin (Czech Republic); Polymer Centre, Faculty of Technology, Tomas Bata University in Zlin, Nam. T.G. Masaryka 275, 762 72 Zlin (Czech Republic); Kuritka, Ivo, E-mail: ivo@kuritka.net [Centre of Polymer Systems, University Institute, Tomas Bata University in Zlin, Nad Ovcirnou 3685, 760 01 Zlin (Czech Republic); Polymer Centre, Faculty of Technology, Tomas Bata University in Zlin, Nam. T.G. Masaryka 275, 762 72 Zlin (Czech Republic); Sedlak, Jakub, E-mail: j1sedlak@ft.utb.cz [Centre of Polymer Systems, University Institute, Tomas Bata University in Zlin, Nad Ovcirnou 3685, 760 01 Zlin (Czech Republic); Polymer Centre, Faculty of Technology, Tomas Bata University in Zlin, Nam. T.G. Masaryka 275, 762 72 Zlin (Czech Republic); Pastorek, Miroslav, E-mail: pastorek@ft.utb.cz [Centre of Polymer Systems, University Institute, Tomas Bata University in Zlin, Nad Ovcirnou 3685, 760 01 Zlin (Czech Republic); Department of Polymer Engineering, Faculty of Technology, Tomas Bata University in Zlin, Nam. T.G. Masaryka 275, 762 72 Zlin (Czech Republic)

    2013-10-15

    Graphical abstract: - Highlights: • Zinc hydroxy sulphate was synthesized in 3 min via microwave hydrothermal route. • Zinc hydroxy sulphate was converted into mesh like porous ZnO by calcining at 900°. • The process of transformation is topotactic. - Abstract: Layered zinc hydroxide sulphate (ZHS) was prepared by microwave-assisted hydrothermal precipitation of zinc sulphate monohydrate with hexamethylenetetramine. Under ambient conditions, the structure of ZHS determined by X-ray diffraction (XRD) was found to be a mixture of zinc hydroxide sulphate pentahydrate Zn{sub 4}SO{sub 4}(OH){sub 6}·5H{sub 2}O and tetrahydrate Zn{sub 4}SO{sub 4}(OH){sub 6}·4H{sub 2}O. Fourier transform infrared (FTIR) spectroscopy was used for characterization of the prepared materials. Based on the interpretation of ZHS's thermal decomposition profile obtained by thermogravimetric analysis, ZnO of high purity was prepared by calcination at 900 °C for 2 h. The structure of the resulting ZnO was confirmed by the XRD. The morphology examination by scanning electron microscopy revealed a porous mesh-like ZnO structure developed from the ZHS precursor at the expense of mass removal due to the release of water and sulphate during the calcination.

  20. Preparation, Structure and Mechanical Properties of Nickel Based Porous Spherical Superalloy

    Institute of Scientific and Technical Information of China (English)

    MI Guo-fa; LI Hong-yu; LIU Xiang-yu; WANG Kuang-fei

    2009-01-01

    The porous superalloy materials with hollow spherical pores were fabricated by using metal powder sintering process.The scanning electron microscope (SEM) observation was applied to the test samples and it revealed that the pores of the porous material exhibited a uniform distribution and the apet;tures were of same size in principle.The sintering necks appeared between adjacent particles on metal skeleton after sintering.The mechanical properties of the test samples were analyzed and the result showed that this kind of materials possessed excellent energy absorption capability,and the compression resistance decreased with increasing the porosity and aperture.

  1. Preparation and hydrogen storage capacity of highly porous activated carbon materials derived from polythiophene

    OpenAIRE

    2011-01-01

    [EN] Highly porous carbons have been successfully synthesized by chemical activation of polythiophene with KOH. The activation process was performed under relatively mild activation conditions, i. e., a KOH/polymer weight ratio of 2 and reaction temperatures in the 600–850 °C range. The porous carbons thus obtained possess very large surface areas, up to 3000 m2/g, and pore volumes of up to 1.75 cm3/g. The pore size distribution of these carbons can be tuned via modification of the activation...

  2. Preparation and Characterization of Nanoscale Zero-Valent Iron-Loaded Porous Sepiolite for Decolorizing Methylene Blue in Aqueous Solutions

    Science.gov (United States)

    Wang, Qingmiao; Ren, Gaofeng; Jia, Feifei; Song, Shaoxian

    2017-02-01

    The preparation and characterization of nanoscale zero-valent iron-loaded porous sepiolite, as well as its application in the decolorization of methylene blue in aqueous solution, have been studied in this work through the measurements of field emission scanning electron microscope with energy dispersive spectrometry, x-ray photoelectron spectrometry, Fourier transform infrared spectroscopy and specific surface area. The results showed that nanoscale zero-valent iron particles were successfully loaded on the surface and interior pores of sepiolite through physical adsorption. It was revealed that the decoloration capacity of methylene blue on nanoscale zero-valent iron-loaded porous sepiolite in water was comparable to that of nanoscale zero-valent iron, and nine times higher than that of natural sepiolite. This indicates that porous sepiolite was a good supporter for the loading of nanoscale zero-valent iron and nanoscale zero-valent iron-loaded sepiolite was a good decolorant because of its high decoloration efficiency and easy separation.

  3. Preparation of porous n-type silicon sample plates for desorption/ionization on silicon mass spectrometry (DIOS-MS).

    Science.gov (United States)

    Tuomikoski, S; Huikko, K; Grigoras, K; Ostman, P; Kostiainen, R; Baumann, M; Abian, J; Kotiaho, T; Franssila, S

    2002-11-01

    This study focuses on porous silicon (pSi) fabrication methods and properties for desorption ionization on silicon mass spectrometry (DIOS-MS). PSi was prepared using electrochemical etching of n-type silicon in HF-ethanol solution. Porous areas were defined by a double-sided illumination arrangement: front-side porous areas were masked by a stencil mask, eliminating the need for standard photolithography, and backside illumination was used for the backside ohmic contact. Backside illumination improved the uniformity of the porosified areas. Porosification conditions, surface derivatizations and storage conditions were explored to optimize pSi area, pore size and pore depth. Chemical derivatization of the pSi surfaces improved the DIOS-MS performance providing better ionization efficiency and signal stability with lower laser energy. Droplet spreading and drying patterns on pSi were also examined. Pore sizes of 50-200 nm were found to be optimal for droplet evaporation and pore filling with the sample liquid, as measured by DIOS efficiency. With DIOS, significantly better detection sensitivity was obtained (e.g. 150 fmol for midazolam) than with desorption ionization from a standard MALDI steel plate without matrix addition (30 pmol for midazolam). Also the noise that disturbs the detection of low-molecular weight compounds at m/z < 500 with MALDI could be clearly reduced with DIOS. Low background MS spectra and good detection sensitivity at the 100-150 fmol level for pharmaceutical compounds were achieved with DIOS-MS.

  4. Green preparation using black soybeans extract for graphene-based porous electrodes and their applications in supercapacitors

    Science.gov (United States)

    Chu, Hwei-Jay; Lee, Chi-Young; Tai, Nyan-Hwa

    2016-08-01

    Adopting an in situ construction strategy, green reduction of graphene oxide (GO) and the formation of an open porous structure are simultaneously completed in a one-pot process using an aqueous extract of an anthocyanin-containing plant, black soybean, as a green reducing agent. The reduced GO prepared by the aqueous extract of black soybean (BRGO), and the hydrogel of BRGO are characterized to better understand the nature of BRGO and the evolution of BRGO from GO. Graphene-based porous electrodes for supercapacitors are fabricated using the BRGO hydrogel as a primary material, and the electrochemical performance of the electrodes are further improved when the BRGO porous electrodes are treated in a microwave oven. Owing to the formation of uniformly dispersed nanoparticles on the graphene surface during the microwave treatment, the electrical conductivity of the electrodes improves by four orders of magnitude and the electroactive surface area also increases by over four times, as a consequence, the capacitance is significantly enhanced, reaching a capacitance of 268.4 F g-1 at a charging current of 0.1 A g-1.

  5. Size-Controlled Pd Nanoparticle Catalysts Prepared by Galvanic Displacement into a Porous Si-Iron Oxide Nanoparticle Host.

    Science.gov (United States)

    Kim, Taeho; Fu, Xin; Warther, David; Sailor, Michael J

    2017-02-21

    Porous silicon nanoparticles containing both Pd and iron oxide nanoparticles are prepared and studied as magnetically recoverable catalysts for organic reductions. The Pd nanoparticles are generated in situ by electroless deposition of Pd(NH3)4(2+), where the porous Si skeleton acts as both a template and as a reducing agent and the released ammonia ligands raise the local pH to exert control over the size of the Pd nanoparticles. The nanocomposites are characterized by transmission electron microscopy, energy-dispersive X-ray spectroscopy, nitrogen adsorption, X-ray diffraction, superconducting quantum interference device magnetization, and dynamic light scattering. The nanocomposite consists of a porous Si nanoparticle (150 nm mean diameter) containing ∼20 nm pores, uniformly decorated with a high loading of surfactant-free Pd nanoparticles (12 nm mean diameter) and superparamagnetic γ-Fe2O3 nanoparticles (∼7 nm mean diameter). The reduction of 4-nitrophenol to 4-aminophenol by sodium borohydride is catalyzed by the nanocomposite, which is stable through the course of the reaction. Catalytic reduction of the organic dyes methylene blue and rhodamine B is also demonstrated. The conversion efficiency and catalytic activity are found to be superior to a commercial Pd/C catalyst compared under comparable reaction conditions. The composite catalyst can be recovered from the reaction mixture by applying an external magnetic field due to the existence of the superparamagnetic iron oxide nanoparticles in the construct. The recovered particles retain their catalytic activity.

  6. Facile preparation of porous Co3O4 nanosheets for high-performance lithium ion batteries and oxygen evolution reaction

    Science.gov (United States)

    Li, Zhangpeng; Yu, Xin-Yao; Paik, Ungyu

    2016-04-01

    Two dimensional (2D) porous nanostructures are of great interest due to their high surface area and rich edge sites, which are favorable for a wide variety of applications. In this communication, well-defined porous Co3O4 nanosheets (PCNSs) are successfully fabricated using graphene oxide as sacrificial template. The 2D structure and porous nature effectively provide more exposed active sites for electrochemical reaction and facilitate easier ion transportation across the sheets. As a result, the as-prepared PCNSs exhibit remarkable lithium storage performance, showing high reversible capacity of 1380 mAh g-1 even after 240 discharge/charge cycles at a current density of 500 mA g-1 and good rate capability (606 mAh g-1 at 10 A g-1). Moreover, it also shows a good electrocatalytic activity for the electrochemical oxygen evolution reaction with an overpotential of 368 mV for driving the current density of 10 mA cm-2 in 1 M KOH and a small Tafel slope of 59 mV dec-1.

  7. Optimal conditions to prepare fine globular granules with a multi-functional rotor processor.

    Science.gov (United States)

    Kimura, Shin-ichiro; Iwao, Yasunori; Ishida, Masayuki; Uchimoto, Takeaki; Miyagishima, Atsuo; Sonobe, Takashi; Itai, Shigeru

    2010-05-31

    The optimal manufacturing conditions to obtain fine globular granules with a narrow size of particle distribution were investigated for a multi-functional rotor processor. A fractional factorial design analysis was undertaken to find out the significant operational conditions influencing the following physical characteristics of the obtained granules: size distribution, roundness and water content. Operational conditions tested were binder flow rate, atomization pressure, slit air flow rate, rotating speed and temperature of inlet air. It was observed that: the proportion of fine particles (106-212 microm) was positively affected by the atomization pressure, while negatively affected by the slit air flow rate; and roundness and water content were positively affected by the binder flow rate. Furthermore, the multiple regression analysis enabled the identification of an optimal operating window for production of fine globular granules. Therefore, the present study demonstrated that the combination of experimental design and multiple regression analysis allows a better understanding of complicated granulating process of multi-functional rotor processor to obtain fine globular granules. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  8. Modal Analysis of the EMU Car-Body in the Preparation Condition Based on Mass Fineness Distribution

    Science.gov (United States)

    Li, Ya-Na; Rao, Ben-Teng; Xie, Su-Ming; Ma, Si-Qun

    Analyzing the car-body modal of EMU is the key of assessing EMU dynamic quality at high speed. The car-body modal can be influenced to same degree by the mass fineness distribution and the rationality of coupling stiffness of suspension device. Considering all equipments layout including internal decoration, FEM of the EMU car-body under preparation based on mass fineness distribution was created and the free modal was carried out with FEA software. The vertical bend frequency 10.03Hz, that is closer to the experimental data, satisfies the relative requirement. And on this basis, different vibration frequencies were studied under different elastic hanging stiffness of suspension device. Vibration frequency change is same on three direction with vertical direction stiffness, which indicate vertical stiffness is more important than the other direction stiffness. Thus these results provide some rational references for EMU car-body structural design.

  9. Comparison on mechanical properties of single layered and bilayered chitosan-gelatin coated porous hydroxyapatite scaffold prepared through freeze drying method

    Science.gov (United States)

    Effendi, M. D.; Gustiono, D.; Lukmana; Ayu, D.; Kurniawati, F.

    2017-02-01

    Biopolymer coated porous hydroxyapatite (HA) scaffolds were prepared for tissue engineering trough freeze drying method and impregnation. in this study, to mimic the mineral and organic component of natural bone, synthetic hydroxapatite (HA) scaffolds coated by polymer were prepared. Highly porous Hap scaffolds, fabricated by synthetic HA impregnation method on polyurethane foam, were coated with polymer coating solution, consisting of chitosan, Gelatin, and bilayered chitosan-gelatin prepared by aging and impregnating technique. For the purpose of comparison, The bare scaffolds without polymer coating layer were investigated. The Bare scaffolds were highly porous and interconnected with a pore size of around 150 µm–714 µm, has porosity at around 67,7% -85,7%, and has mechanical strength at around 0.06 Mpa - 0.071 Mpa, which is suitable for osteoblast cell Proliferation. Chitosan coated porous HA scaffold and gelatin coated porous HA scaffold had mechanical strength at around 0.81-0.85 Mpa, and 1.32-1.34 Mpa, respectively, with weight ratio of biopolymer and Hap was around 18%-22%. To compare these results, the coating on the bare scaffold with gelatin and chitosan had been conducted. Based on the result of FTIR, it could be concluded that coating procedure applied on porous hydroxy apatite (HA) coated by gelatin, chitosan coated HA scaffold, and bilayered Gelatin-chitosan coated porous HA scaffold, confirming that for allsampleshad no significant chemical effect on the coating structure. The compressive strength of bilayered Gelatin-chitosan coated HA scaffold had middle values between the rest, at around 1,06-1.2 Mpa for the samples at the same weight ratio of biopolymer: HA (around 18% - 22%). These results also confirming that coating by gelatin on porous hydroxyapatite was highest compresive strength and can be applied to improve mechanical properties of porous hydroxyapatite bare scaffold

  10. Preparation of the cactus-like porous manganese oxide assisted with surfactant sodium dodecyl sulfate for supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Yu [State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, No. 30 College Road, Beijing 100083 (China); Li, Jianling, E-mail: lijianling@ustb.edu.cn [State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, No. 30 College Road, Beijing 100083 (China); Yan, Gang; Xu, Guofeng; Xue, Qingrui [State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, No. 30 College Road, Beijing 100083 (China); Kang, Feiyu [Lab of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)

    2015-02-05

    Highlights: • The cactus-like porous MnO{sub 2} was synthesized by hydrothermal method assisted with SDS. • The MnO{sub 2} exhibits a max specific capacitance of 187.8 F g{sup −1} (0.2 A g{sup −1}, 1 M Na{sub 2}SO{sub 4}). • Excellent cycling stability: 92.9% capacitance retention after 1000 cycles. - Abstract: The cactus-like porous manganese dioxide (MnO{sub 2}) was synthesized by a simple hydrothermal method assisted with the surfactant sodium dodecyl sulfate (SDS). The morphology, composition, property of the prepared materials were characterized by X-ray diffraction (XRD), Raman spectroscopy, Brunauer–Emmett–Teller (BET), Field Emission Scanning Electron Microscopy (FE-SEM) and Transmission Electron Microscopy (TEM) measurements. It was found that the sample without surfactant was composed of nanoflakes which piling up together, whereas in the presence of the surfactant, the MnO{sub 2} samples with the max specific surface of 321.9 m{sup 2} g{sup −1} showed a porous cactus-like microstructure, consisted of uniform nanowires and porous nanoflakes. The electrochemical performances of the MnO{sub 2} with and without surfactant were analyzed using Cyclic Voltammetry (CV), Electrochemical Impedance Spectrometry (EIS) and Galvanostatic Charge–Discharge (GCD) tests. The results showed that the MnO{sub 2} assisted with 1 wt.% SDS displayed a higher specific capacitance of 187.8 F g{sup −1} at the current density of 0.2 A g{sup −1} compared with the MnO{sub 2} without surfactant (134.8 F g{sup −1}). And such MnO{sub 2} samples with higher specific capacitance also afford an excellent cyclic stability with the capacity retention of approximately 92.9% after 1000 cycles in 1 M Na{sub 2}SO{sub 4} solution at a current density of 1 A g{sup −1}. The superior capacitive performance of the as-prepared materials could be attributed to its unique cactus-like porous structure, which provided good electronic conductivity, large specific surface area as

  11. Preparation, characterization and in vitro dissolution behavior of porous biphasic α/β-tricalcium phosphate bioceramics.

    Science.gov (United States)

    Xie, Lu; Yu, Haiyang; Deng, Yi; Yang, Weizhong; Liao, Li; Long, Qin

    2016-02-01

    The ideal bone tissue engineering scaffolds are long-cherished with the properties of interconnected macroporous structures, adjustable degradation and excellent biocompatibility. Here, a series of porous α/β-tricalcium phosphate (α/β-TCP) biphasic bioceramics with different phase ratios of α-TCP and β-TCP were successfully synthesized by heating an amorphous calcium phosphate precursor. The chemical and morphological characterization showed that α- and β-TCP phases co-existed in the α/β-TCP bioceramics and they had interconnected pore structures with size between 200 and 500μm. The in vitro dissolution behavior and bioactivity of the dual α/β-TCP were also probed in static and dynamic SBF for the first time. The results revealed that α/β-TCP scaffolds had good in vitro bioactivity, as the formation of bone-like apatite layers was induced on the scaffolds after mineralization in SBF. Moreover, dissolution rate of α/β-TCP bioceramics in dynamic environment was higher than that under static condition. Compared with monophasic TCP ceramics, these porous α/β-TCP bioceramics displayed a tailored dissolution rate proportionate to the TCP content (α and β) in the materials. Further, the degradation profile of porous α/β-TCP was well-described by Avrami equation. The porous dual α/β-TCP bioceramics with controllable degradation behavior hold great potential to be applied in bone tissue engineering as bone substitutes.

  12. Porous niobium coatings fabricated with selective laser melting on titanium substrates: Preparation, characterization, and cell behavior.

    Science.gov (United States)

    Zhang, Sheng; Cheng, Xian; Yao, Yao; Wei, Yehui; Han, Changjun; Shi, Yusheng; Wei, Qingsong; Zhang, Zhen

    2015-08-01

    Nb, an expensive and refractory element with good wear resistance and biocompatibility, is gaining more attention as a new metallic biomaterial. However, the high price of the raw material, as well as the high manufacturing costs because of Nb's strong oxygen affinity and high melting point have limited the widespread use of Nb and its compounds. To overcome these disadvantages, porous Nb coatings of various thicknesses were fabricated on Ti substrate via selective laser melting (SLM), which is a 3D printing technique that uses computer-controlled high-power laser to melt the metal. The morphology and microstructure of the porous Nb coatings, which had pores ranging from 15 to 50 μm in size, were characterized with scanning electron microscopy (SEM). The average hardness of the coating, which was measured with the linear intercept method, was 392±37 HV. In vitro tests of the porous Nb coating which was monitored with SEM, immunofluorescence, and CCK-8 counts of cells, exhibited excellent cell morphology, attachment, and growth. The simulated body fluid test also proved the bioactivity of the Nb coating. Therefore, these new porous Nb coatings could potentially be used for enhanced early biological fixation to bone tissue. In addition, this study has shown that SLM technique could be used to fabricate coatings with individually tailored shapes and/or porosities from group IVB and VB biomedical metals and their alloys on stainless steel, Co-Cr, and other traditional biomedical materials without wasting raw materials.

  13. Preparation of advanced porous structures by stereolithography for application in tissue engineering

    NARCIS (Netherlands)

    Melchels, Ferry Petrus Wilhelmus

    2010-01-01

    Stereolithography is a solid freeform fabrication technique, with which computer-designed objects can be automatically fabricated from photo-curable polymer resins in a layer-by-layer manner. In tissue engineering, there is a need for porous structures with well-defined external geometries and inte

  14. Porous hydrogel of wool keratin prepared by a novel method: an extraction with guanidine/2-mercaptoethanol solution followed by a dialysis.

    Science.gov (United States)

    Ozaki, Yuki; Takagi, Yusuke; Mori, Hideki; Hara, Masayuki

    2014-09-01

    In this study, we show a novel simple method to prepare a sponge-like porous keratin hydrogel through the extraction of wool keratin in a solution containing guanidine hydrochloride and 2-mercaptoethanol followed by dialysis for both aggregation of keratin and recrosslink. The gel had a highly porous structure and a fast-swelling property in rehydration after freeze-drying. It had also high mechanical strength both in the tensile test and the measurement of dynamic viscoelasticity. Three types of animal cells, PC12 cells, HOS cells and murine embryonic fibroblasts, well attached and grew on the surface of the porous hydrogel.

  15. Porous niobium coatings fabricated with selective laser melting on titanium substrates: Preparation, characterization, and cell behavior

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Sheng [Science and Technology on Power Beam Processes Laboratory, Beijing Aeronautical Manufacturing Technology Research Institute (BAMTRI), Beijing 100024 (China); State Key Lab of Materials Processing and Die & Mould Technology, Huazhong University of Science and Technology, Wuhan 430074 (China); Cheng, Xian; Yao, Yao; Wei, Yehui [Department of Stomatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022 (China); Han, Changjun; Shi, Yusheng [State Key Lab of Materials Processing and Die & Mould Technology, Huazhong University of Science and Technology, Wuhan 430074 (China); Wei, Qingsong, E-mail: wqs_xn@163.com [State Key Lab of Materials Processing and Die & Mould Technology, Huazhong University of Science and Technology, Wuhan 430074 (China); Zhang, Zhen, E-mail: zhangzhentitanium@163.com [State Key Lab of Materials Processing and Die & Mould Technology, Huazhong University of Science and Technology, Wuhan 430074 (China); Department of Stomatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022 (China)

    2015-08-01

    Nb, an expensive and refractory element with good wear resistance and biocompatibility, is gaining more attention as a new metallic biomaterial. However, the high price of the raw material, as well as the high manufacturing costs because of Nb's strong oxygen affinity and high melting point have limited the widespread use of Nb and its compounds. To overcome these disadvantages, porous Nb coatings of various thicknesses were fabricated on Ti substrate via selective laser melting (SLM), which is a 3D printing technique that uses computer-controlled high-power laser to melt the metal. The morphology and microstructure of the porous Nb coatings, which had pores ranging from 15 to 50 μm in size, were characterized with scanning electron microscopy (SEM). The average hardness of the coating, which was measured with the linear intercept method, was 392 ± 37 HV. In vitro tests of the porous Nb coating which was monitored with SEM, immunofluorescence, and CCK-8 counts of cells, exhibited excellent cell morphology, attachment, and growth. The simulated body fluid test also proved the bioactivity of the Nb coating. Therefore, these new porous Nb coatings could potentially be used for enhanced early biological fixation to bone tissue. In addition, this study has shown that SLM technique could be used to fabricate coatings with individually tailored shapes and/or porosities from group IVB and VB biomedical metals and their alloys on stainless steel, Co–Cr, and other traditional biomedical materials without wasting raw materials. - Highlights: • Porous Nb coating was firstly fabricated on Ti substrate by SLM technique. • Morphology, microstructure and hardness of the coating were characterized. • In vitro test of the coating showed good cell attachment, morphology and growth.

  16. Research progress in preparation process and application of porous starch%多孔淀粉制备工艺及应用研究进展

    Institute of Scientific and Technical Information of China (English)

    张斌; 陈国

    2012-01-01

    多孔淀粉是一种用途广泛的环境友好型材料,其制备方法有物理法、化学法和生物法。在简述多孔淀粉基本性质的基础上,首先介绍了物理法和酸法制备多孔淀粉的工艺及研究现状,然后详细阐述了生物法制备多孔淀粉涉及的酶的选择、成孔机理、生淀粉的选择、预处理和制备工艺,最后对多孔淀粉的应用研究和未来多孔淀粉的研究方向进行了展望。%Porous starch is a versatile environmentally friendly materials.The methods of porous starch preparation include physical, chemical and biological. With the brief introduction of the basic properties of porous starch, it presented the technological processes and research status of the physical and chemical methods for porous starch preparation.Furthermore,the paper focused on the selection of enzymes,the pore formation mechanism ,the selection of raw starch,the pretreatment and the processes of the biological method for porous starch preparation. In the end,the application and future development of porous starch were prospected.

  17. Preparation of NiO-CuO-MgO fine powders by ultrasonic spray pyrolysis for carbon nanofibers synthesis

    Science.gov (United States)

    Krasnikova, Irina V.; Mishakov, Ilya V.; Bauman, Yury I.; Karnaukhov, Timofey M.; Vedyagin, Aleksey A.

    2017-09-01

    Carbon nanofibers with uniform diameter distribution are of great importance to be applied in composite materials production. Characteristics of the final carbon product obtained via catalytic chemical vapour deposition are known to be determined by the catalyst characteristics and the process conditions. In this work, ultrasonic spray pyrolysis was used for the preparation of uniform-sized NiO-CuO-MgO fine powders. Spherical particles of 170-340 nm in diameter were obtained in a temperature range of 400-600 °C. Synthesized powders exhibited high catalytic activity in CCVD of ethylene with the formation of CNF with relatively narrow diameter distribution (60 ± 20 nm).

  18. X-ray diffraction and high-resolution TEM observations of biopolymer nanoskin-covered metallic copper fine particles: preparative conditions and surface oxidation states.

    Science.gov (United States)

    Yonezawa, Tetsu; Uchida, Yoshiki; Tsukamoto, Hiroki

    2015-12-28

    Metallic copper fine particles used for electro conductive pastes were prepared by the chemical reduction of cupric oxide microparticles in the presence of gelatin. After reduction, the fine particles were collected by decantation with pH control and washing, followed by drying at a moderate temperature. The surface oxidation state of the obtained copper fine particles could be considerably varied by altering the pH of the particle dispersion, as shown by X-ray diffraction and high-resolution transmission electron microscopy. Our results strongly indicate that decantation under a nitrogen atmosphere can prevent the oxidation of copper fine particles but a slight oxidation was found.

  19. Facile preparation of hierarchically porous carbon using diatomite as both template and catalyst and methylene blue adsorption of carbon products.

    Science.gov (United States)

    Liu, Dong; Yuan, Peng; Tan, Daoyong; Liu, Hongmei; Wang, Tong; Fan, Mingde; Zhu, Jianxi; He, Hongping

    2012-12-15

    Hierarchically porous carbons were prepared using a facile preparation method in which diatomite was utilized as both template and catalyst. The porous structures of the carbon products and their formation mechanisms were investigated. The macroporosity and microporosity of the diatomite-templated carbons were derived from replication of diatom shell and structure-reconfiguration of the carbon film, respectively. The macroporosity of carbons was strongly dependent on the original morphology of the diatomite template. The macroporous structure composed of carbon plates connected by the pillar- and tube-like macropores resulted from the replication of the central and edge pores of the diatom shells with disk-shaped morphology, respectively. And another macroporous carbon tubes were also replicated from canoe-shaped diatom shells. The acidity of diatomite dramatically affected the porosity of the carbons, more acid sites of diatomite template resulted in higher surface area and pore volume of the carbon products. The diatomite-templated carbons exhibited higher adsorption capacity for methylene blue than the commercial activated carbon (CAC), although the specific surface area was much smaller than that of CAC, due to the hierarchical porosity of diatomite-templated carbons. And the carbons were readily reclaimed and regenerated. Copyright © 2012 Elsevier Inc. All rights reserved.

  20. Ultra low Pt-loading electrode prepared by displacement of electrodeposited Cu particles on a porous carbon electrode

    Energy Technology Data Exchange (ETDEWEB)

    Liao, M.J. [The State Key Laboratory of Power Transmission Equipment and System Security and New Technology, School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044 (China); Wei, Z.D.; Li, L. [The State Key Laboratory of Power Transmission Equipment and System Security and New Technology, School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044 (China); School of Material Science and Engineering, Chongqing University, Chongqing 400044 (China); Chen, S.G.; Ji, M.B.; Wang, Y.Q. [School of Material Science and Engineering, Chongqing University, Chongqing 400044 (China)

    2010-08-15

    Ultra low Pt-loading and high Pt utilization electrodes were prepared by displacement of electrodeposited Cu on a porous carbon electrode. Copper particles were electrodeposited on a porous carbon electrode (PCE) by four-step deposition (FSD) at first. The size and dispersion of deposited Cu particles were markedly improved with application of the FSD. The Cu deposits were then displaced by platinum as dipping a Cu/PCE in a platinum salt solution. Sequentially, Pt particles supported on the PCE were obtained. The Pt/PCE electrode prepared via the FSD of Cu overcomes the problem of the hydrogen evolution reaction accompanied with direct platinum electrochemical deposition, and has a high Pt dispersion. The single cell consisting of the electrodes Pt/PCE via the FSD of Cu outputs a power of 0.45 W cm{sup -2} with ultra low Pt loadings of 0.196 mg cm{sup -2} MEA (0.098 mg cm{sup -2} per each side of the MEA) at no backpressure of reactant gases. (author)

  1. Controllable Preparation of Ultrathin Sandwich-Like Membrane with Porous Organic Framework and Graphene Oxide for Molecular Filtration

    Science.gov (United States)

    Zhu, Yuanzhi; Xu, Danyun; Zhao, Qingshan; Li, Yang; Peng, Wenchao; Zhang, Guoliang; Zhang, Fengbao; Fan, Xiaobin

    2015-10-01

    Porous organic frameworks (POFs) based membranes have potential applications in molecular filtration, despite the lack of a corresponding study. This study reports an interesting strategy to get processable POFs dispersion and a novel ultrathin sandwich-like membrane design. It was accidentally found that the hydrophobic N-rich Schiff based POFs agglomerates could react with lithium-ethylamine and formed stable dispersion in water. By successively filtrating the obtained POFs dispersion and graphene oxide (GO), we successfully prepared ultrathin sandwich-like hybrid membranes with layered structure, which showed significantly improved separation efficiency in molecular filtration of organic dyes. This study may provide a universal way to the preparation of processable POFs and their hybrid membranes with GO.

  2. Preparation of PVA/PEI ultra-fine fibers and their composite membrane with PLA by electrospinning.

    Science.gov (United States)

    Dong, Cunhai; Yuan, Xiaoyan; He, Mingyu; Yao, Kangde

    2006-01-01

    Ultra-fine fibers of poly(vinyl alcohol)/polyethylenimine (PVA/PEI) were prepared by electrospinning of their blend solutions in water. Effects of PVA/PEI mass ratio and the polymer concentration on the fiber morphology were discussed by analysis of scanning electron micrographs. Results showed that uniform ultra-fine fibers could be obtained from an 8% PVA/PEI solution with 75:25 mass ratio. It was supposed that the introduction of PVA could promote electrospinning of PEI by weakening the intermolecular interaction and increasing solution viscosity. A composite membrane of PVA/PEI with poly(D,L-lactide) (PLA) was produced by co-electrospinning simultaneously from the aqueous 8% PVA/PEI (75:25) solution and a 20% PLA solution in N,N-dimethylformamide in two separated syringes. Fourier transform infrared spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy verified the existence of PVA/PEI and PLA in the fibrous membrane. We attempted to incorporate PEI with PLA as ultra-fine fibers to diminish the acidic inflammation caused by biodegradation of PLA. The fibrous composite membrane of PVA/PEI-PLA could provide better biocompatibility and would be used as drug-delivery carriers or tissue-engineering scaffolds.

  3. Permeability mapping in porous media by magnetization prepared centric-scan SPRITE

    Science.gov (United States)

    Romanenko, Konstantin V.; Balcom, Bruce J.

    2011-02-01

    The ability of porous media to transmit fluids is commonly referred to as permeability. The concept of permeability is central for hydrocarbon recovery from petroleum reservoirs and for studies of groundwater flow in aquifers. Spatially resolved measurements of permeability are of great significance for fluid dynamics studies. A convenient concept of local Darcy's law is suggested for parallel flow systems. The product of porosity and mean velocity images in the plane across the average flow direction is directly proportional to permeability. Single Point Ramped Imaging with T 1 Enhancement (SPRITE) permits reliable quantification of local fluid content and flow in porous media. It is particularly advantageous for reservoir rocks characterized by fast magnetic relaxation of a saturating fluid. Velocity encoding using the Cotts pulsed field gradient scheme improves the accuracy of measured flow parameters. The method is illustrated through measurements of 2D permeability maps in a capillary bundle, glass bead packs and composite sandstone samples.

  4. Preparation and characterizations of heat storage material combining porous metal with molten salt

    Institute of Scientific and Technical Information of China (English)

    王华; 何方; 戴永年; 胡建杭

    2003-01-01

    A new type of heat storage materials combining high temperature molten salts phases change latent heat thermal storage materials, PCM with porous metals sensible heat thermal storage materials was developed. The process was expressed as following: firstly, it is necessary to heat up the molten salts phases change materials to molten; and then the porous metals are put into the molten bath; after being held for 1-3 h, the composite heat thermal storage materials lumps are taken out of the molten bath and cooled to atmospheric temperature; the last step is to electrodeposit a layer metal coat on the surface of the material lumps. The new type of heat storage material integrates the advantages of both solid sensible heat thermal storage materials and high temperature phases change latent heat thermal storage materials. The metal-base heat storage materials enjoy some favorable characteristics such as higher heat charge-discharge rate, higher heat storage density and better mechanical strength.

  5. Porous hydrogel of wool keratin prepared by a novel method: An extraction with guanidine/2-mercaptoethanol solution followed by a dialysis

    Energy Technology Data Exchange (ETDEWEB)

    Ozaki, Yuki; Takagi, Yusuke; Mori, Hideki; Hara, Masayuki, E-mail: hara@b.s.osakafu-u.ac.jp

    2014-09-01

    In this study, we show a novel simple method to prepare a sponge-like porous keratin hydrogel through the extraction of wool keratin in a solution containing guanidine hydrochloride and 2-mercaptoethanol followed by dialysis for both aggregation of keratin and recrosslink. The gel had a highly porous structure and a fast-swelling property in rehydration after freeze-drying. It had also high mechanical strength both in the tensile test and the measurement of dynamic viscoelasticity. Three types of animal cells, PC12 cells, HOS cells and murine embryonic fibroblasts, well attached and grew on the surface of the porous hydrogel. - Graphical abstract: We show a novel simple method to prepare a sponge-like porous keratin hydrogel (A, B) through the extraction of wool keratin in a solution containing guanidine hydrochloride and 2-mercaptoethanol followed by dialysis for both aggregation of keratin and recrosslink. The gel had a highly porous structure (B) and a fast-swelling property in rehydration after freeze-drying. It had also high mechanical strength both in the tensile test (C) and the measurement of dynamic viscoelasticity (D). Three types of animal cells, PC12 cells (E), HOS cells (F) and murine embryonic fibroblasts (MEFs) (G), well attached and grew on the surface of the porous hydrogel. - Highlights: • We prepared a sponge-like porous keratin hydrogel by a novel method. • We used guanidine with 2-mercaptoethanol to extract keratin from wool fiber. • Extracted keratin was recrosslinked to form a porous keratin hydrogel in dialysis. • The keratin hydrogel had a high mechanical strength. • Three types of cells attached on the keratin hydrogel proliferated well.

  6. A Modified Porous Titanium Sheet Prepared by Plasma-Activated Sintering for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Yukimichi Tamaki

    2010-01-01

    Full Text Available This study aimed to develop a contamination-free porous titanium scaffold by a plasma-activated sintering within an originally developed TiN-coated graphite mold. The surface of porous titanium sheet with or without a coated graphite mold was characterized. The cell adhesion property of porous titanium sheet was also evaluated in this study. The peak of TiC was detected on the titanium sheet processed with the graphite mold without a TiN coating. Since the titanium fiber elements were directly in contact with the carbon graphite mold during processing, surface contamination was unavoidable event in this condition. The TiC peak was not detectable on the titanium sheet processed within the TiN-coated carbon graphite mold. This modified plasma-activated sintering with the TiN-coated graphite mold would be useful to fabricate a contamination-free titanium sheet. The number of adherent cells on the modified titanium sheet was greater than that of the bare titanium plate. Stress fiber formation and the extension of the cells were observed on the titanium sheets. This modified titanium sheet is expected to be a new tissue engineering material in orthopedic bone repair.

  7. Preparation of porous TiO{sub 2}/ZnO composite film and its photocathodic protection properties for 304 stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Hongmei; Liu, Wei, E-mail: weiliu@ouc.edu.cn; Cao, Lixin; Su, Ge; Duan, Ruijing

    2014-05-01

    Highlights: • Porous TiO{sub 2}/ZnO composite films were prepared on the 304 stainless steel. • The preparation parameters of the composite films were optimized. • Porous TiO{sub 2}/ZnO composite films provide an effective photogenerated cathodic protection for 304 stainless steel. - Abstract: TiO{sub 2}/ZnO composite films with porous structure were prepared on the 304 stainless steel (304SS) by the sol-gel method and heating treatment. The crystalline phase and morphology of as-prepared TiO{sub 2}/ZnO composite films were characterized systematically by X-ray diffraction (XRD), scanning electron microscope (SEM) and ultraviolet–visible (UV–vis) spectroscopy, respectively. The influences of Ti/Zn molar ratio and the annealing temperature on the photoelectric property of the samples have been investigated and their photocathodic protection performances for 304 stainless steel under dark and UV conditions have also been evaluated in 3.0% NaCl solution by the electrochemical measurements. The results indicate that porous TiO{sub 2}/ZnO composite film has a great enhancement of the light absorption and photoelectric property under UV illumination. This can be ascribed to the mutual effect of TiO{sub 2}/ZnO heterojunctions and the porous structures in the composite films, which provide a better photogenerated cathodic protection for 304SS.

  8. Polymer composites and porous materials prepared by thermally induced phase separation and polymer-metal hybrid methods

    Science.gov (United States)

    Yoon, Joonsung

    The primary objective of this research is to investigate the morphological and mechanical properties of composite materials and porous materials prepared by thermally induced phase separation. High melting crystallizable diluents were mixed with polymers so that the phase separation would be induced by the solidification of the diluents upon cooling. Theoretical phase diagrams were calculated using Flory-Huggins solution thermodynamics which show good agreement with the experimental results. Porous materials were prepared by the extraction of the crystallized diluents after cooling the mixtures (hexamethylbenzene/polyethylene and pyrene/polyethylene). Anisotropic structures show strong dependence on the identity of the diluents and the composition of the mixtures. Anisotropic crystal growth of the diluents was studied in terms of thermodynamics and kinetics using DSC, optical microscopy and SEM. Microstructures of the porous materials were explained in terms of supercooling and dendritic solidification. Dual functionality of the crystallizable diluents for composite materials was evaluated using isotactic polypropylene (iPP) and compatible diluents that crystallize upon cooling. The selected diluents form homogeneous mixtures with iPP at high temperature and lower the viscosity (improved processability), which undergo phase separation upon cooling to form solid particles that function as a toughening agent at room temperature. Tensile properties and morphology of the composites showed that organic crystalline particles have the similar effect as rigid particles to increase toughness; de-wetting between the particle and iPP matrix occurs at the early stage of deformation, followed by unhindered plastic flow that consumes significant amount of fracture energy. The effect of the diluents, however, strongly depends on the identity of the diluents that interact with the iPP during solidification step, which was demonstrated by comparing tetrabromobisphenol-A and

  9. A hierarchical porous carbon membrane from polyacrylonitrile/polyvinylpyrrolidone blending membranes:Preparation, characterization and electrochemical capacitive performance

    Institute of Scientific and Technical Information of China (English)

    Huili Fan; Fen Ran∗; Xuanxuan Zhang; Haiming Song; Wenxia Jing; Kuiwen Shen; Lingbin Kong; Long Kang

    2014-01-01

    Novel hierarchical porous carbon membranes were fabricated through a simple carbonization procedure of well-defined blending polymer membrane precursors containing the source of carbon polyacrylonitrile (PAN) and an additive of polyvinylpyrrolidone (PVP), which was prepared using phase inversion method. The as-fabricated materials were further used as the active electrode materials for supercapacitors. The effects of PVP concentration in the casting solution on structure feature and electrochemical capacitive performance of the as-prepared carbon membranes were also studied in detail. As the electrode material for supercapacitor, a high specific capacitance of 278.0 F/g could be attained at a current of 5 mA/cm2 and about 92.90%capacity retention could be maintained after 2000 charge/discharge cycles in 2 mol/L KOH solution with a PVP concentration of 0.3 wt%in the casting solution. The facile hierarchical pore structure preparation method and the good electrochemical capacitive performance make the prepared carbon membrane particularly promising for use in supercapacitor.

  10. Facile preparation of nitrogen/sulfur co-doped and hierarchical porous graphene hydrogel for high-performance electrochemical capacitor

    Science.gov (United States)

    Li, Jinhui; Zhang, Guoping; Fu, Chaopeng; Deng, Libo; Sun, Rong; Wong, Ching-Ping

    2017-03-01

    Nitrogen/sulfur co-doped and hierarchical porous graphene hydrogels (DHGHs) are prepared by facile self-assembly process. The results show that the pH values of preparation process significantly affect the microstructures and electrochemical properties of DHGHs and the mechanism has been discussed. The as-prepared DHGHs can be directly used as binder-free electrodes to assemble full-cell supercapacitor devices. It is surprising that the DHGHs prepared at basic condition (DHGH-12) delivers a specific capacitance of 251 F g-1 (0.5 A g-1). Moreover, the DHGH-12 shows rectangular cyclic voltammetry shape at a high scan rate of 3000 mV s-1 and symmetrical galvanostatic charge/discharge curves at 100 A g-1 which exhibits a specific capacitance of 136.5 F g-1, a high energy density of 4.74 Wh kg-1 and high power density of 25.47 kW kg-1. Additionally, DHGH-12 presents superior cycling stability (96.8% retention after 2000 cycles at 20 A g-1) in 6 M KOH solution. Therefore, the novel DHGHs can be considered as promising candidate for high energy density supercapacitors at high rates.

  11. Preparation of Filling Porous Osteoconduction Materials and Its Animal Experiment Study

    Institute of Scientific and Technical Information of China (English)

    CHEN Xiaoming; WANG Jing; CHEN Weimin; LI Dezhong

    2011-01-01

    Titanium rods were processed into implant samples with cavity and groove in which was filled with HAP/β-TCP porous osteoconduction composite materials in order to increase the mechanical stability of the implant in vivo. The phase compositions of the composite was characterized by X-ray diffraction (XRD) and scanning electron microscopy(SEM). Histological evaluation showed that the biogradable composite could enhanced the ability of new bone formation. The composite can conduct new bone tissue growing into the cavities gradually after implanted into animal, and then achieve mechanical fixation. The filling biogradable compound exhibited excellent biocompatibility, which combined with the new bone tissues tightly without inflammation and loosing.

  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. Fast Preparation of Porous MnO/C Microspheres as Anode Materials for Lithium-Ion Batteries

    Science.gov (United States)

    Su, Jing; Liang, Hao; Gong, Xian-Nian; Lv, Xiao-Yan; Long, Yun-Fei; Wen, Yan-Xuan

    2017-01-01

    Porous MnO/C microspheres have been successfully fabricated by a fast co-precipitation method in a T-shaped microchannel reactor. The structures, compositions, and electrochemical performances of the obtained MnO/C microspheres are characterized by X-ray diffraction, field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (HRTEM), Brunauer–Emmett–Teller analysis, charge-discharge testing, cyclic voltammograms, and electrochemical impedance spectra. Experimental results reveal that the as-prepared MnO/C, with a specific surface area of 96.66 m2·g−1 and average pore size of 24.37 nm, exhibits excellent electrochemical performance, with a discharge capacity of 655.4 mAh·g−1 after cycling 50 times at 1 C and capacities of 808.3, 743.7, 642.6, 450.1, and 803.1 mAh·g−1 at 0.2, 0.5, 1, 2, and 0.2 C, respectively. Moreover, the controlled method of using a microchannel reactor, which can produce larger specific surface area porous MnO/C with improved cycling performance by shortening lithium-ion diffusion distances, can be easily applied in real production on a large scale. PMID:28587120

  14. Preparation of porous paper composites with ruthenium hydroxide and catalytic alcohol oxidation in a multiphase gas–liquid–solid reaction

    Energy Technology Data Exchange (ETDEWEB)

    Homma, Taichi [Department of Agro-Environmental Sciences, Graduate School of Bioresource and Bioenvironmental Sciences, and Biotron Application Center, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581 (Japan); Processing Development Research Laboratory, Kao Corporation, 2606 Akabane, Ichikai-machi, Haga-gun, Tochigi 321-3497 (Japan); Kitaoka, Takuya, E-mail: tkitaoka@agr.kyushu-u.ac.jp [Department of Agro-Environmental Sciences, Graduate School of Bioresource and Bioenvironmental Sciences, and Biotron Application Center, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581 (Japan)

    2014-05-01

    Highlights: • Flexible and porous paper-structured Ru(OH){sub x} catalysts were prepared successfully. • Ru(OH){sub x} catalysts were dispersed on the ceramic fiber networks of paper composites. • Catalytic oxidation of benzyl alcohol proceeded efficiently in three-phase reactions. • Paper catalysts exhibited much higher performance than conventional solid catalysts. - Abstract: In situ synthesis of ruthenium hydroxide catalysts on a microporous fiber-network structure of ceramic paper composites was achieved. The efficient catalytic oxidation of alcohol was investigated in a heterogeneous, multiphase gas–liquid–solid reaction. A simple papermaking technique and subsequent immersion in a ruthenium chloride solution allowed us to fabricate novel-concept microstructured catalysts. The paper-structured catalysts possess micropores ca. 30 μm in diameter with high porosity of ca. 90%. They exhibited much higher catalytic efficiency in the O{sub 2}-mediated oxidation in toluene of benzyl alcohol to benzaldehyde in a fixed bed external loop reactor, as compared with conventional pellet- and bead-type solid catalysts. This excellent catalytic effect is possibly attributed to the porous paper composite microstructure like microreactors.

  15. PREPARATION OF POROUS NANOCOMPOSITE SCAFFOLDS WITH HONEYCOMB MONOLITH STRUCTURE BY ONE PHASE SOLUTION FREEZE DRYING METHOD

    Institute of Scientific and Technical Information of China (English)

    Yang Xu; Duo Zhang; Zong-liang Wang; Zhan-tuan Gao; Pei-biao Zhang; Xue-si Chen

    2011-01-01

    Biodegradable porous nanocomposite scaffolds of poly(lactide-co-glycolide) (PLGA) and L-lactic acid (LAc) oligomer surface-grafted hydroxyapatite nanoparticles (op-HA) with a honeycomb monolith structure were fabricated with the single-phase solution freeze-drying method. The effects of different freezing temperatures on the properties of the scaffolds, such as microstructures, compressive strength, cell penetration and cell proliferation were studied. The highly porous and well interconnected scaffolds with a tunable pore structure were obtained. The effect of different freezing temperature (4℃, -20℃, -80℃ and -196℃) was investigated in relation to the scaffold morphology, the porosity varied from 91.2% to 83.0% and the average pore diameter varied from (167.2 ± 62.6) pm to (11.9 ± 4.2) μm while the σ10 increased significantly. The cell proliferation were decreased and associated with the above-mentioned properties. Uniform distribution of op-HA particles and homogeneous roughness of pore wall surfaces were found in the 4℃ frozen scaffold. The 4℃ frozen scaffold exhibited better cell penetration and increased cell proliferation because of its larger pore size, higher porosity and interconnection. The microstmctures described here provide a new approach for the design and fabrication of op-HA/PLGA based scaffold materials with potentially broad applicability for replacement of bone defects.

  16. Porous Polyimide Membranes Prepared by Wet Phase Inversion for Use in Low Dielectric Applications

    Directory of Open Access Journals (Sweden)

    Jung Ah Lim

    2013-04-01

    Full Text Available A wet phase inversion process of polyamic acid (PAA allowed fabrication of a porous membrane of polyimide (PI with the combination of a low dielectric constant (1.7 and reasonable mechanical properties (Tensile strain: 8.04%, toughness: 3.4 MJ/m3, tensile stress: 39.17 MPa, and young modulus: 1.13 GPa, with further thermal imidization process of PAA. PAA was simply synthesized from purified pyromellitic dianhydride (PMDA and 4,4-oxydianiline (ODA in two different reaction solvents such as γ-butyrolactone (GBL and N-methyl-2-pyrrolidinone (NMP, which produce Mw/PDI of 630,000/1.45 and 280,000/2.0, respectively. The porous PAA membrane was fabricated by the wet phase inversion process based on a solvent/non-solvent system via tailored composition between GBL and NMP. The porosity of PI, indicative of a low electric constant, decreased with increasing concentration of GBL, which was caused by sponge-like formation. However, due to interplay between the low electric constant (structural formation and the mechanical properties, GBL was employed for further exploration, using toluene and acetone vs. DI-water as a coagulation media. Non-solvents influenced determination of the PAA membrane size and porosity. With this approach, insight into the interplay between dielectric properties and mechanical properties will inform a wide range of potential low-k material applications.

  17. A porous poly(vinylidene fluoride) gel electrolyte for lithium ion batteries prepared by using salicylic acid as a foaming agent

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, H.P. [Department of Material Science, Fudan University, Shanghai 200433 (China); Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433 (China); Zhang, P.; Li, G.C.; Wu, Y.P. [Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200433 (China); Sun, D.L. [Department of Material Science, Fudan University, Shanghai 200433 (China)

    2009-04-01

    A porous gel polymer electrolyte based on poly(vinylidene fluoride) (PVDF) was for the first time prepared via a foaming technology using salicylic acid as a foaming agent. The pores are evenly distributed with an average diameter of about 400 nm. The results from TG/DTA, XRD and FT-IR show that there are no vesicant residues after the PVDF film was heat-treated at 200 C to get the porous structure. When the film is gelled with liquid electrolyte, the ion conductivity can be up to 4.8 x 10{sup -3} S cm{sup -1} at room temperature and the activation energy for ionic transfer is 10.2 kJ mol{sup -1}. LiCoO{sub 2} cathode also presents good cycling performance. These primary results show great promise for this simple method to prepare porous gel polymer electrolytes for practical application in lithium ion batteries. (author)

  18. Preparation and application of porous nitrogen-doped graphene obtained by co-pyrolysis of lignosulfonate and graphene oxide.

    Science.gov (United States)

    Zhao, Hai-Bo; Wang, Wen-Dong; Lü, Qiu-Feng; Lin, Ting-Ting; Lin, Qilang; Yang, Haijun

    2015-01-01

    Nitrogen-doped graphene with in-plane porous structure was fabricated by simple co-pyrolysis of lignosulfonate and graphene oxide in the presence of urea. Lignosulfonate first performs as a dispersant adsorbed on the surface of graphene oxide to prevent the aggregation of graphene oxide sheets for preparing homogeneous nitrogen-containing precursor, and then acts as a porogen to render graphene sheets with nanopores in the pyrolysis process of the nitrogen-containing precursor. Urea was used as a nitrogen source to incorporate nitrogen atoms into graphene basal plane. The special nanoporous structure combined with nitrogen content of 7.41at.% endows the nitrogen-doped graphene electrode material with super capacitance up to 170Fg(-1), high rate performance, and excellent cycling stability.

  19. Preparation of hybrid thiol-acrylate emulsion-templated porous polymers by interfacial copolymerization of high internal phase emulsions.

    Science.gov (United States)

    Langford, Caitlin R; Johnson, David W; Cameron, Neil R

    2015-05-01

    Emulsion-templated highly porous polymers (polyHIPEs), containing distinct regions differing in composition, morphology, and/or properties, are prepared by the simultaneous polymerization of two high internal phase emulsions (HIPEs) contained within the same mould. The HIPEs are placed together in the mould and subjected to thiol-acrylate photopolymerization. The resulting polyHIPE material is found to contain two distinct semicircular regions, reflecting the composition of each HIPE. The original interface between the two emulsions becomes a copolymerized band between 100 and 300 μm wide, which is found to be mechanically robust. The separate polyHIPE layers are distinguished from one another by their differing average void diameter, chemical composition, and extent of contraction upon drying.

  20. Comparison of liquid-based preparation and conventional smear of fine-needle aspiration cytology of lymph node.

    Science.gov (United States)

    Singh, Priya; Rohilla, Manish; Dey, Pranab

    2016-01-01

    In this paper, we have compared the cytomorphologic characteristics of liquid-based preparation (LBP) [SurePath (SP)] cytology and conventional smear (CP) preparations on fine-needle aspiration (FNAC) material by a semi-quantitative scoring system for cases of lymphadenopathy. In this prospective study, a total of 52 consecutive cases of FNAC of lymphadenopathy were included. The first pass was used for CP followed by LBP with the help of SP technique. The smears were independently compared and assessed by two observers (PS and PD). The semiquantitative grading was compared in two groups by Wilcoxon signed-rank test. The background information, cell architecture, pleomorphism, nuclear and cytoplasmic details, and three-dimensional structures were significantly different in LBP and CP smears. Liquid-based cytology (LBC) is a relatively simple technique, which exhibits good nuclear and cytoplasmic details with the absence of obscuring background material. Even the number of slides and area per slide to be screened were less than the conventional preparation but caution must be applied to interpret the slides and secure a diagnosis, especially if LBC is the first and only method applied for diagnosis.

  1. Hierarchical Porous Polymer Beads Prepared by Polymerization-induced Phase Separation and Emulsion-template in a Microfluidic Device

    Institute of Scientific and Technical Information of China (English)

    Wei-cai Wang; Yan-xiong Pan; Kai Shi; Chao Peng; Xiang-ling Ji

    2014-01-01

    Porous polymer beads (PPBs) containing hierarchical bimodal pore structure with gigapores and meso-macropores were prepared by polymerization-induced phase separation (PIPS) and emulsion-template technique in a glass capillary microfluidic device (GCMD).Fabrication procedure involved the preparation of water-in-oil emulsion by emulsifying aqueous solution into the monomer solution that contains porogen.The emulsion was added into the GCMD to fabricate the (water-in-oil)-in-water double emulsion droplets.The flow rate of the carrier continuous phase strongly influenced the formation mechanism and size of droplets.Formation mechanism transformed from dripping to jetting and size of droplets decreased from 550 μm to 250 μm with the increase in flow rate of the carrier continuous phase.The prepared droplets were initiated for polymerization by on-line UV-irradiation to form PPBs.The meso-macropores in these beads were generated by PIPS because of the presence ofporogen and gigapores obtained from the emulsion-template.The pore morphology and pore size distribution of the PPBs were investigated extensively by scanning electron microscopy and mercury intrusion porosimetry (MIP).New pore morphology was formed at the edge of the beads different from traditional theory because of different osmolarities between the water phase of the emulsion and the cartier continuous phase.The morphology and proportion of bimodal pore structure can be tuned by changing the kind and amount of porogen.

  2. Fine-needle aspiration cytology of mammary fibroadenoma: a comparison of ThinPrep® and cytospin preparations.

    Science.gov (United States)

    Ly, Thai Yen; Barnes, Penny J; Macintosh, Rebecca F

    2011-03-01

    Mammary fibroadenoma (FA) is a lesion frequently sampled and diagnosed by fine-needle aspiration (FNA). Accurate cytologic diagnosis of this common benign lesion is important as this can lead to non-surgical, conservative management when breast imaging and clinical examination are concordant. In most instances, a confident diagnosis of FA is possible because of a characteristic cytologic appearance that includes hypercellularity, large epithelial cell groups, staghorn epithelial configurations, stromal fragments, and numerous background stripped nuclei. Nevertheless, FAs can be diagnostically challenging because of shared cytomorphologic features with other benign lesions and low-grade carcinoma. As such, FA is a well-recognized source of false results on FNA cytology. Furthermore, there are reports that newer thin layer cytopreparatory techniques, including the ThinPrep® (TP) system (Hologic Corp., Bedford, MA), alter the appearance of FA on FNA compared to conventional preparations and may compromise accurate cytologic diagnosis. Copyright © 2010 Wiley-Liss, Inc.

  3. Preparation and photochromic properties of ultra-fine H3PW11MoO40/PVA fibre mats

    Science.gov (United States)

    Yang, Guo-Cheng; Gong, Jian; Pan, Yan; Cui, Xiu-Jun; Shao, Chang-Lu; Guo, Yi-Hang; Wen, Shang-Bin; Qu, Lun-Yu

    2004-07-01

    Novel photochromic materials, H3PW11MoO40/Poly (vinyl alcohol) (PVA) ultra-fine fibre mats containing different weight percentages of H3PW11MoO40, have been prepared from different H3PW11MoO40/PVA solutions by an electrospinning technique. IR spectroscopy, wide-angle x-ray diffraction, and scanning electron microscope spectroscopy are used to characterize the fibre mats. Results of viscosity and conductivity measurements of the solutions indicate that lower viscosity and higher conductivity favour the formation of thin fibres without beads. When irradiated with ultraviolet light (313.2 nm), the colour of the fibre mats changes from white to blue, and the mats show reversible photochromism. IR and ESR spectra of the irradiated fibre mats indicate a conceivable photochromic mechanism, i.e. MoVI is reduced under ultraviolet irradiation. Meanwhile, PVA is oxidized to unsaturated ketone or aldehyde.

  4. Preparation of Nano-porous Materials(Ⅰ) by Polymerization of Amphiphile Self-assemblies

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The polymerization of amphiphilic self-assemblies is a promising method to synthesize nano-structured materials with novel properties. These materials have many attractive features for their application in biomedical area and materials science, such as catalysis, separation, surface modification, and therapeutics areas. A general review on the polymerization of lipids and surfactant self-assemblies to amphiphilic self-assemblies is given in this paper with 49 参考文献. The polymerization and the subsequently resulted structure of lipids in different morphologies are summarized. The polymerization of polymerizable surfactants(surfmers) in emulsion and liquid crystalline phases are also discussed. The potential application of new nano-porous materials is briefly described.

  5. Preparation of aligned porous chitin nanowhisker foams by directional freeze-casting technique.

    Science.gov (United States)

    Zhou, Yiming; Fu, Shiyu; Pu, Yunqiao; Pan, Shaobo; Ragauskas, Arthur J

    2014-11-04

    Structured biofoams with aligned porous structures were fabricated from nanosized chitin by employing a directional freeze-casting technique. The effects of the freezing conditions and slurry formulation on nanochitin foam morphology were investigated. The morphology of obtained foams was characterized using scanning electron microscopy (SEM). It was found that the pore structure of the obtained foams was a likewise of the ice crystals formed during the directional freezing. The results indicate that directional freeze-casting protocol can significantly influence the morphological features and microstructures of the obtained biofoams which could have numerous applications, including engineered carriers, scaffolds, filters and specifically as a template for potential multi-layered composites after infusion with a second phase.

  6. Spectroscopic Properties of Nd3+-Doped High Silica Glass Prepared by Sintering Porous Glass

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A new kind of Nd3+-doped high silica glass (SiO2>96% (mass fraction)) was obtained by sintering porous glass impregnated with Nd3+ ions. The absorption and luminescence properties of high silica glass doped with different Nd3+ concentrations were studied. The intensity parameters Ωt (t=2, 4, 6), spontaneous emission probability, fluorescence lifetime, radiative quantum efficiency, fluorescence branching ratio, and stimulated emission cross section were calculated using the Judd-Ofelt theory. The optimal Nd3+ concentration in high silica glass was 0.27% (mole fraction) because of its high quantum efficiency and emission intensity. By comparing the spectroscopic parameters with other Nd3+-doped oxide glasses and commercial silicate glasses, the Nd3+-doped high silica glasses are likely to be a promising material used for high power and high repetition rate lasers.

  7. Preparation of porous microsphere-scaffolds by electrohydrodynamic forming and thermally induced phase separation

    Energy Technology Data Exchange (ETDEWEB)

    Ghanbar, Hanif; Luo, C.J.; Bakhshi, Poonam [Department of Mechanical Engineering, University College London, Torrington Place, London, WC1E 7JE (United Kingdom); Day, Richard [Division of Medicine, University College London, Rockefeller Building, 21 University Street, London, WC1E 6JJ (United Kingdom); Edirisinghe, Mohan, E-mail: m.edirisinghe@ucl.ac.uk [Department of Mechanical Engineering, University College London, Torrington Place, London, WC1E 7JE (United Kingdom)

    2013-07-01

    The availability of forming technologies able to mass produce porous polymeric microspheres with diameters ranging from 150 to 300 μm is significant for some biomedical applications where tissue augmentation is required. Moreover, appropriate assembly of microspheres into scaffolds is an important challenge to enable direct usage of the as-formed structures in treatments. This work reports the production of poly (glycolic-co-lactic acid) and poly (ε-caprolactone) microspheres under ambient conditions using one-step electrohydrodynamic jetting (traditionally known as atomisation) and thermally induced phase separation (TIPS). To ensure robust production for practical uses, this work presents 12 comprehensive parametric mode mappings of the diameter distribution profiles of the microspheres obtained over a broad range of key processing parameters and correlating of this with the material parameters of 5 different polymer solutions of various concentrations. Poly (glycolic-co-lactic acid) (PLGA) in Dimethyl carbonate (DMC), a low toxicity solvent with moderate conductivity and low dielectric constant, generated microspheres within the targeted diameter range of 150–300 μm. The fabrication of the microspheres suitable for formation of the scaffold structure is achieved by changing the collection method from distilled water to liquid nitrogen and lyophilisation in a freeze dryer. Highlights: ► EHDA is a unique method for production of the desired size of microspheres. ► Polymer solution properties are used to tailor the size distribution of spheres. ► Process control parameters (flow rate and applied voltage) are key in size control. ► Combination of EHDA with TIPS provides porous microspheres for assembly of scaffold.

  8. Effect of substrate porosity on photoluminescence properties of ZnS films prepared on porous Si substrates by pulsed laser deposition

    Institute of Scientific and Technical Information of China (English)

    WANG Cai-feng; LI Qing-shan; ZHANG Li-chun; LV Lei; QI Hong-xia

    2007-01-01

    ZnS films were deposited on porous Si (PS) substrates with different porosities by pulsed laser deposition. The photoluminescence spectra of the samples were measured to study the effect of substrate porosity on luminescence properties of ZnS/porous Si composites. After deposition of ZnS films, the red photoluminescence peak of porous Si shows a slight blueshift compared with as-prepared porous Si samples. With an increase of the porosity, a green emission at about 550 nm was observed which may be ascribed to the defect-center luminescence of ZnS films, and the photoluminescence of ZnS/porous Si composites is very close to white light. Good crystal structures of the samples were observed by x-ray diffraction,showing that ZnS films were grown in preferred orientation. Due to the roughness of porous Si surface, some cracks appear in ZnS films, which could be seen from scanning electron microscope images.

  9. Amorphous solid dispersion of cyclosporine A prepared with fine droplet drying process: Physicochemical and pharmacokinetic characterization.

    Science.gov (United States)

    Suzuki, Hiroki; Moritani, Tatsuru; Morinaga, Tadahiko; Seto, Yoshiki; Sato, Hideyuki; Onoue, Satomi

    2017-03-15

    The present study aimed to develop an amorphous solid dispersion (ASD) of cyclosporine A (CsA) by a fine droplet drying (FDD) process for improvement in oral absorption of CsA. CsA and hydroxypropyl cellulose-SSL were dissolved in 1,4-dioxane, and the solution was powdered by the FDD process to obtain the ASD formulation of CsA (ASD/CsA). The ASD/CsA was characterized in terms of morphology, particle size distribution, crystallinity, dissolution behavior, physicochemical stability, and pharmacokinetic behavior in rats. The ASD/CsA was obtained in the form of uniform spherical particles, and the span factor was calculated to be ca. 0.4. CsA in the formulation existed in an amorphous state. The ASD/CsA exhibited a higher dissolution behavior of CsA than amorphous CsA, whereas storage of the ASD/CsA under accelerated conditions led to impairment in the dissolution behavior. The constant release of CsA from non-aged ASD/CsA was observed during dissolution testing. After oral administration of CsA samples (10mg-CsA/kg) in rats, the ASD/CsA showed a high and sustained plasma concentration of CsA as evidenced by a 18-fold increase in the oral bioavailability of CsA compared with amorphous CsA. From these findings, the FDD process might be an efficacious option for the ASD formulation of CsA with enhanced biopharmaceutics properties. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. 微胶囊多孔淀粉的制备及应用研究进展%Progress in Preparation and Application of Microencapsulated Porous Starch

    Institute of Scientific and Technical Information of China (English)

    尹卓林; 解乐福; 李艳杰; 马烽

    2014-01-01

    Porous starch has large specific pore volume and specific surface area , strong adsorption capacity and good mechanical strength. Microencapsulated porous starch is prepared by porous starch microencapsulation , which has high storage stability and can be used more conveniently. Microencapsulated porous starch has brilliant application prospects in food,pharmaceutical and pesticide etc. In this paper, preparation methods, characteristics and applications of microencapsulated porous starch are reviewed , and its potential development is prospected.%多孔淀粉具有较大的比孔容和比表面积、较强的吸附能力和良好的机械强度。将多孔淀粉微胶囊化制备微胶囊多孔淀粉,可延长包埋物质的贮存稳定性且使用更方便,在食品、医药、农药等领域有着广阔的应用前景。本文综述了微胶囊多孔淀粉的制备方法、性能及应用,并对其发展前景进行了展望。

  11. 多孔金属氧化物的制备方法简述%STUDY ON PREPARATION METHOD OF POROUS METAL OXIDE

    Institute of Scientific and Technical Information of China (English)

    刘友文; 曹元媛; 沈毅

    2011-01-01

    Porous crystals have multiplicity structure and broad application prospects for gas separation, porous electrodes and storage media. So, more and more scientists have been engaged in their research and development. The preparation of porous metal oxides obtained wide attention, and has achieved some achievements. This paper reviews some researches on the preparation method of porous metal oxides on the basis of a bdefing on the basic concepts of porous material.%多孔晶体由于其结构的多样性,使得它在气体分离、多孔电极、储存介质等方面有着广泛的应用.吸引了越来越多的科学工作者从事这方面的研究与开发,其中多孔金属氧化物的制备得到了广泛的重视并取得了一定的成果.本文在简要介绍多孔材料的基本概念的基础上综述了近年来一些制备多孔金属氧化物的方法.

  12. Preparation and electrical characterization of ultra-fine powder scandia-stabilized zirconia

    Institute of Scientific and Technical Information of China (English)

    周静; 张赫; 徐宏; 薛倩楠; 黄小卫; 冯宗玉; 龙志奇

    2016-01-01

    Ultrafine powders of scandia-stabilized zirconia (ScSZ) were prepared by the co-precipitation method, using ZrOCl2 and ScO2 as raw materials and NH3·H2O as a precipitant. In this paper, the optimum process parameters were investigated. The pH of the reaction solution directly impacted the precursor structure, which further affected the obtained crystal forming. Many experiment methods of thermogravimetric analysis and differential thermal analysis (TG-DTA), X-ray diffraction (XRD), transmission electron microscopy (TEM), Raman spectroscopy (Raman), and nitrogen adsorption were employed to characterize the ScSZ powder. The structure transition mechanism from cubic to rhombohedral was discussed. In addition, the electrical conductivity of the powders was also studied after dry-pressing and calcining. The results showed that the structure of ScSZ with complete crystal surface belonged to the cubic phase. The crystallite sizes of the powders prepared are about 60–80 nm, meet the conditions of (D90–D10)/2D50≤1, and ex-hibited the good flow properties. The electrical conductivity was more than 190 mS/cm in air measured at 850 ºC.

  13. Photocatalytic ability of TiO2 porous film prepared by modified spray pyrolysis deposition technique

    National Research Council Canada - National Science Library

    SUGIYAMA, Osamu; OKUYA, Masayuki; KANEKO, Shoji

    2009-01-01

    In a spray pyrolysis deposition (SPD) technique, deposition of film material and formation of surface structure are simultaneously occur, therefore, it is suitable for the preparation of microstructure-controlled thin films...

  14. Preparation and Evaluation of Solid Dispersion Tablets by a Simple and Manufacturable Wet Granulation Method Using Porous Calcium Silicate.

    Science.gov (United States)

    Fujimoto, Yumi; Hirai, Nobuaki; Takatani-Nakase, Tomoka; Takahashi, Koichi

    2016-01-01

    The aim of this study was to prepare and evaluate solid dispersion tablets containing a poorly water-soluble drug using porous calcium silicate (PCS) by a wet granulation method. Nifedipine (NIF) was used as the model poorly water-soluble drug. Solid dispersion tablets were prepared with the wet granulation method using ethanol and water by a high-speed mixer granulator. The binder and disintegrant were selected from 7 and 4 candidates, respectively. The dissolution test was conducted using the JP 16 paddle method. The oral absorption of NIF was studied in fasted rats. Xylitol and crospovidone were selected as the binder and disintegrant, respectively. The dissolution rates of NIF from solid dispersion formulations were markedly enhanced compared with NIF powder and physical mixtures. Powder X-ray diffraction (PXRD) confirmed the reduced crystallinity of NIF in the solid dispersion formulations. Fourier transform infrared (FT-IR) showed the physical interaction between NIF and PCS in the solid dispersion formulations. NIF is present in an amorphous state in granules prepared by the wet granulation method using water. The area under the plasma concentration-time curve (AUC) and peak concentration (C(max)) values of NIF after dosing rats with the solid dispersion granules were significantly greater than those after dosing with NIF powder. The solid dispersion formulations of NIF prepared with PCS using the wet granulation method exhibited accelerated dissolution rates and superior oral bioavailability. This method is very simple, and may be applicable to the development of other poorly water-soluble drugs.

  15. Morphology, luminescence, and electrical resistance response to H 2 and CO gas exposure of porous InP membranes prepared by electrochemistry in a neutral electrolyte

    Science.gov (United States)

    Volciuc, O.; Monaico, E.; Enachi, M.; Ursaki, V. V.; Pavlidis, D.; Popa, V.; Tiginyanu, I. M.

    2010-11-01

    Porous InP membranes have been prepared by anodization of InP wafers with electron concentration of 1 × 10 17 cm -3 and 1 × 10 18 cm -3 in a neutral NaCl electrolyte. The internal surfaces of pores in some membranes were modified by electrochemical deposition of gold in a pulsed voltage regime. Photoluminescence and photosensitivity measurements indicate efficient light trapping and porous surface passivation. The photoluminescence and electrical resistivity of the membranes are sensitive to the adsorption of H 2 and CO gas molecules. These properties are also influenced by the deposition of Au nanoparticles inside the pores.

  16. Morphology, luminescence, and electrical resistance response to H{sub 2} and CO gas exposure of porous InP membranes prepared by electrochemistry in a neutral electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Volciuc, O.; Monaico, E.; Enachi, M. [National Center for Materials Study and Testing, Technical University of Moldova, Bd. Stefan cel Mare 168, Chisinau 2004 (Moldova, Republic of); Ursaki, V.V., E-mail: ursaki@yahoo.com [Institute of Applied Physics, Academy of Sciences of Moldova, Academy str. 5, Chisinau 2028 (Moldova, Republic of); Pavlidis, D. [Fachgebiet fuer Hoechstfrequenzelektronik, Technische Universitaet Darmstadt, Merckstrasse 25, Darmstadt 64283 (Germany); Popa, V. [National Center for Materials Study and Testing, Technical University of Moldova, Bd. Stefan cel Mare 168, Chisinau 2004 (Moldova, Republic of); Fachgebiet fuer Hoechstfrequenzelektronik, Technische Universitaet Darmstadt, Merckstrasse 25, Darmstadt 64283 (Germany); Tiginyanu, I.M. [National Center for Materials Study and Testing, Technical University of Moldova, Bd. Stefan cel Mare 168, Chisinau 2004 (Moldova, Republic of); Institute of Electronic Engineering and Nanotechnologies, Academy of Sciences of Moldova, Academy str. 3/3, Chisinau 2028 (Moldova, Republic of)

    2010-11-15

    Porous InP membranes have been prepared by anodization of InP wafers with electron concentration of 1 x 10{sup 17} cm{sup -3} and 1 x 10{sup 18} cm{sup -3} in a neutral NaCl electrolyte. The internal surfaces of pores in some membranes were modified by electrochemical deposition of gold in a pulsed voltage regime. Photoluminescence and photosensitivity measurements indicate efficient light trapping and porous surface passivation. The photoluminescence and electrical resistivity of the membranes are sensitive to the adsorption of H{sub 2} and CO gas molecules. These properties are also influenced by the deposition of Au nanoparticles inside the pores.

  17. Preparation of Zeolitic Imidazolate Framework-8 (ZIF-8) Membrane on Porous Polymeric Support via Contra-Diffusion Method

    KAUST Repository

    Tan, Xiaoyu

    2016-05-18

    In the last decade, many attempts were made to put metal organic frameworks (MOFs) in industrial applications, but most of these efforts weren’t successfully. As one of the few MOFs produced on industrial scale, ZIF-8 has interesting pore size, huge internal surface area and great thermal and chemical stability. Therefore, ZIF-8 might become the first MOF, which will be applied in industrial separation processes. In this thesis, a synthesis study is presented, which leads to a cheap and convenient way to
fabricate defect-free and thin ZIF-8 membranes on porous polymeric supports showing high selectivity and high gas permeance. The ZIF-8 layers were produced via a contra-diffusion method. Several polymeric membranes were employed as support in this study, such as PAN, PEI, PSU, PA and PTSC. We studied the influence of the polymeric support properties for the ZIF-8 membrane preparation and optimized the ZIF-8 preparation conditions. The ZIF-8 membranes were characterized via scanning electron microscopy (SEM) and X-ray diffraction (XRD). For gas permeation test, we chose a Wicke-Kallenbach apparatus to measure membrane’s gas permeance and selectivity. One of the best ZIF-8 membranes exhibited a hydrogen permeance of 3.45 × 10-8 mol m-2 s-1 Pa-1 and
an ideal selectivity of hydrogen over propane of about 500.

  18. Preparation and catalytic effect of porous Co3O4 on the hydrogen storage properties of a Li-B-N-H system

    Directory of Open Access Journals (Sweden)

    You Li

    2017-02-01

    Full Text Available A porous Co3O4 with a particle size of 1–3 µm was successfully prepared by heating Co-based metal organic frameworks MOF-74(Co up to 500 °C in air atmospheric conditions. The as-prepared porous Co3O4 significantly reduced the dehydrogenation temperatures of the LiBH4-2LiNH2 system and improved the purity of the released hydrogen. The LiBH4-2LiNH2-0.05/3Co3O4 sample started to release hydrogen at 140 °C and released hydrogen levels of approximately 9.7 wt% at 225 °C. The end temperature for hydrogen release was lowered by 125 °C relative to that of the pristine sample. Structural analyses revealed that the as-prepared porous Co3O4 is in-situ reduced to metallic Co, which functions as an active catalyst, reducing the kinetic barriers and lowering the dehydrogenation temperatures of the LiBH4-2LiNH2 system. More importantly, the porous Co3O4-containing sample exhibited partially improved reversibility for hydrogen storage in the LiBH4-2LiNH2 system.

  19. Biodegradable and bioactive porous scaffold structures prepared using fused deposition modeling.

    Science.gov (United States)

    Korpela, Jyrki; Kokkari, Anne; Korhonen, Harri; Malin, Minna; Närhi, Timo; Seppälä, Jukka

    2013-05-01

    Three-dimensional printing (3DP) refers to a group of additive manufacturing techniques that can be utilized in tissue engineering applications. Fused deposition modeling (FDM) is a 3DP method capable of using common thermoplastic polymers. However, the scope of materials applicable for FDM has not been fully recognized. The purpose of this study was to examine the creation of biodegradable porous scaffold structures using different materials in FDM and to determine the compressive properties and the fibroblast cell response of the structures. To the best of our knowledge, the printability of a poly(ε-caprolactone)/bioactive glass (PCL/BAG) composite and L-lactide/ε-caprolactone 75/25 mol % copolymer (PLC) was demonstrated for the first time. Scanning electron microscope (SEM) images showed BAG particles at the surface of the printed PCL/BAG scaffolds. Compressive testing showed the possibility of altering the compressive stiffness of a scaffold without changing the compressive modulus. Compressive properties were significantly dependent on porosity level and structural geometry. Fibroblast proliferation was significantly higher in polylactide than in PCL or PCL/BAG composite. Optical microscope images and SEM images showed the viability of the cells, which demonstrated the biocompatibility of the structures. Copyright © 2012 Wiley Periodicals, Inc.

  20. Preparation and characterization of a micro-porous polymer electrolyte with cross-linking network structure for dye-sensitized solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Wei, T.C.; Wan, C.C.; Wang, Y.Y. [Department of Chemical Engineering, National Tsing-Hua University, 101, Section 2, Kuang Fu Road, Hsin-Chu 300 (China)

    2007-12-14

    A PVdF-HFP/PEG/PEGDMA cross-linking film has been prepared as the electrolyte for dye-sensitized solar cell (DSSC). The film can be made porous by controlling the evaporation behavior of solvents. Room temperature ionic conductivity of the micro-porous film exceeds 1 mS/cm. In addition, we also evaluated the significance of cell gap in DSSC by analyzing the impedance spectroscopy of the cell with polymer electrolyte. Finally, by decreasing the film thickness, the DSSC equipped with 11 {mu}m, micro-porous and cross-linked film showed a conversion efficiency over 4% and 5% under 1 and 0.16 Sun, respectively. (author)

  1. A Novel Porous Carrier Found in Nature for Nanocomposite Materials Preparation: A Case Study of Artemia Egg Shell-Supported TiO2 for Formaldehyde Removal

    Directory of Open Access Journals (Sweden)

    Sufeng Wang

    2015-01-01

    Full Text Available Artemia egg shells have an asymptotic sized pore structure (pore diameter: 500 nm–2500 nm, which could be used as a porous carrier for the preparation of nanocomposite materials. The objective of the present study was to prepare shell-supported TiO2 using a naturally porous carrier, Artemia egg shell, and to exhibit a case study of shell-supported TiO2 for formaldehyde removal. Characterization of shell-TiO2 using SEM-EDS, TEM, and XRD proved that Artemia shell with asymptotic reduction pores (pore diameter: 500 nm–2500 nm can be used as the carrier for nanocomposite materials. Artemia egg shell-supported TiO2 in polycrystalline-like nanostructures can be used for the high efficiency removal (adsorption and degradation of formaldehyde under visible light. Our results suggest that iron, one of the shell’s components, should broaden the absorption of visible light and enhance the photocatalytic efficiency of nanotitanium dioxide under visible light. Due to their interesting absorption and formaldehyde removal qualities, Artemia egg shell, as a novel naturally porous carrier for nanocomposite materials preparation, especially in the preparation of nanocatalysts, is worthy of further study.

  2. PREPARATION AND PROPERTIES OF MACRO-POROUS CHELATE RESINS OF CROSSLINKED POLYSTYRENE BEARING DITHIOCARBAMATE GROUPS

    Institute of Scientific and Technical Information of China (English)

    CHEN Yiyong; GU Zhenmei

    1983-01-01

    The title resins (DTC resins) with high adsorption capacity were prepared. The influences of various reaction conditions of amination and dithiocarboxylation were examined. The adsorption capacities of the produced DTC resin for Hg2+, Cu2+, Zn2+ and Cd2+ are 4.40, 2.44, 1.77 and 1.36mmol/g, respectively. It is highly effective in collecting traces of heavy metal ions in water over a wide pH range. The conversion of the functional groups were confirmed by the IR-spectra and elementary analysis.

  3. The application of prepared porous carbon materials: Effect of different components on the heavy metal adsorption.

    Science.gov (United States)

    Song, Min; Wei, Yuexing; Yu, Lei; Tang, Xinhong

    2016-06-01

    In this study, five typical municipal solid waste (MSW) components (tyres, cardboard, polyvinyl chloride (PVC), acrylic textile, toilet paper) were used as raw materials to prepare four kinds of MSW-based carbon materials (paperboard-based carbon materials (AC1); the tyres and paperboard-based carbon materials (AC2); the tyres, paperboard and PVC-based carbon materials (AC3); the tyres, paperboard, toilet paper, PVC and acrylic textile-based carbon materials (AC4)) by the KOH activation method. The characteristic results illustrate that the prepared carbon adsorbents exhibited a large pore volume, high surface area and sufficient oxygen functional groups. Furthermore, the application of AC1, AC2, AC3, AC4 on different heavy metal (Cu(2+), Zn(2+), Pb(2+), Cr(3+)) removals was explored to investigate their adsorption properties. The effects of reaction time, pH, temperature and adsorbent dosage on the adsorption capability of heavy metals were investigated. Comparisons of heavy metal adsorption on carbon of different components were carried out. Among the four samples, AC1 exhibits the highest adsorption capacity for Cu(2+); the highest adsorption capacities of Pb(2+) and Zn(2+) are obtained for AC2; that of Cr(3+) are obtained for AC4. In addition, the carbon materials exhibit better adsorption capability of Cu(2+) and Pb(2+) than the other two kind of metal ions (Zn(2+) and Cr(3+)).

  4. Polydopamine meets porous membrane: A versatile platform for facile preparation of membrane adsorbers.

    Science.gov (United States)

    Fan, Jinxin; Luo, Jianquan; Chen, Xiangrong; Wan, Yinhua

    2016-05-27

    Polydopamine, as an intermediate layer coated on PES membrane, was applied to fabricate various membrane adsorbers. Anion-exchange, hydrophobic interaction and affinity membrane adsorbers prepared by this facile method exhibited a high selectivity in fractionation of IgG (immunoglobulin)/HSA (human serum albumin) mixture. The anion-exchange membrane adsorber containing polyethylenimine (PEI) improved the HSA purity from 17.7% to 96.7%; The hydrophobic interaction membrane adsorber with Dodecyl mercaptan (DDM) as ligand obtained an IgG purity of 94.6%; Histidine attached affinity membrane chromatography achieved nearly a 100% purity of IgG. The present work indicated that the polydopamine layer not only activated membrane surface to attach various adsorptive ligands under the mild condition, but also reduced non-specific adsorption. Due to the versatile conjunction function, this facile mussel-inspired coating is also promising for the preparation of diverse membrane adsorbers. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Iron oxide porous nanorods with different textural properties and surface composition: Preparation, characterization and electrochemical lithium storage capabilities

    Energy Technology Data Exchange (ETDEWEB)

    Tartaj, Pedro; Amarilla, Jose M. [Instituto de Ciencia de Materiales de Madrid (CSIC), Campus Universitario de Cantoblanco, 28049, Madrid (Spain)

    2011-02-15

    We here report a method for the facile and large scale preparation of lithium-ion battery anodes based on {alpha}-Fe{sub 2}O{sub 3} (hematite) nanorods with different textural characteristics and surface composition. The method combines electrostatically driven self-assembly approaches with specific adsorption and magnetically easy to disrupt soft aggregates. Special emphasis has been set to correlate the textural characteristics (porosity) and surface composition (core, core-nanoshell and core-double nanoshells) of nanorods with their electrochemical response. Thus, we have shown that nanorods present a nanophase whose specific capacity strongly depends on the lithium transport distances (nanorods with slit-shape mesopores running along their long axis vs. non-porous or surface blocked nanorods). We have also shown that the capacity retention of this nanophase after several charge-discharge processes depends on maintaining the structural integrity of the nanorods. Essential for the success of this latter study has been the use of nanorods that offer a simple tool (oriented X-ray line broadening) to follow their electrochemical grinding. Our data suggest that {alpha}-Fe{sub 2}O{sub 3} mesoporous nanorods could both operate at a voltage and retain a capacity similar to that of nanostructured lithium titanates anodes if actions are taken to prevent electrochemical grinding. (author)

  6. Preparation and (68)Ga-radiolabeling of porous zirconia nanoparticle platform for PET/CT-imaging guided drug delivery.

    Science.gov (United States)

    Polyak, Andras; Naszalyi Nagy, Lívia; Mihaly, Judith; Görres, Sebastian; Wittneben, Alexander; Leiter, Ina; Bankstahl, Jens P; Sajti, Laszlo; Kellermayer, Miklós; Zrínyi, Miklós; Ross, Tobias L

    2017-04-15

    This paper describes the preparation of gallium-68 ((68)Ga) isotope labeled porous zirconia (ZrO2) nanoparticle (NP) platform of nearly 100nm diameter and its first pharmacokinetic and biodistribution evaluation accomplished with a microPET/CT (μPet/CT) imaging system. Objectives of the investigations were to provide a nanoparticle platform which can be suitable for specific delivery of various therapeutic drugs using surface attached specific molecules as triggering agents, and at the same time, suitable for positron emission tomography (PET) tracing of the prospective drug delivery process. Radiolabeling was accomplished using DOTA bifunctional chelator. DOTA was successfully adsorbed onto the surface of nanoparticles, while the (68)Ga-radiolabeling method proved to be simple and effective. In the course of biodistribution studies, the (68)Ga-labeled DOTA-ZrNPs showed proper radiolabeling stability in their original suspension and in blood serum. μPet/CT imaging studies confirmed a RES-biodistribution profile indicating stable nano-sized labeled particles in vivo. Results proved that the new method offers the opportunity to examine further specifically targeted and drug payload carrier variants of zirconia NP systems using PET/CT imaging.

  7. Preparation and characterization of porous DVB copolymers and their applicability for adsorption (solid-phase extraction) of phenol compounds

    Science.gov (United States)

    Sobiesiak, Magdalena; Podkoscielna, Beata

    2010-12-01

    Using DVB, three new porous copolymers in the form of microspheres were prepared, characterized and used as adsorbents for phenol and its chlorinated derivatives. As the monomers: 4,4'-bis(maleimidodiphenyl)methane (BM), 2,3-bis(2-hydroxy-3-methylacryloyloxy-propoxy)naphthalene (2,3-NAF) and 2,3-epoxypropyl methacrylate (GLY) were used. All the studied materials were synthesized under the same conditions by means of suspension copolymerization. The DVB copolymers were characterized by elemental analysis, FTIR spectroscopy, TG and DSC analyses and N 2 sorption. The off-line solid-phase extraction method (SPE) was used to estimate sorption properties of the copolymers. The results show that the newly obtained materials are mesoporous but their shape of pores and chemical structures are different. BM-DVB and GLY-DVB are characterized by slit-shaped pores and wide pore size distribution. 2,3-NAF-DVB also possesses slit pores but distribution of pore size is narrower. Of those studied BM-DVB is the most interesting material. It has good sorption properties and heat resistance.

  8. Facile preparation of three-dimensional multilayer porous MnO2/reduced graphene oxide composite and its supercapacitive performance

    Science.gov (United States)

    Li, Yiju; Wang, Guiling; Ye, Ke; Cheng, Kui; Pan, Yue; Yan, Peng; Yin, Jinling; Cao, Dianxue

    2014-12-01

    Three-dimensional (3D) multilayer porous MnO2/reduced graphene oxide composites are coated on a nickel foam substrate (denoted as MnO2/R-GO@Ni-foam) by a facile and scalable spray method following by low temperature annealing. The composite electrodes are characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Fourier transform infrared spectroscopy. The content of MnO2 in the MnO2/R-GO@Ni-foam composites is determined by thermal gravimetric analysis. The supercapacitive performance of the composite electroides is investigated by cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy. The results show that the MnO2/R-GO@Ni-foam composite displays a high specific capacitance of 267 F g-1 at 0.25 A g-1 and excellent capacitance retention of 89.5% after 1000 cycles. This study provides a facile way for the preparation of composite electrodes for high-performance supercapacitor.

  9. Preparation of gelatin based porous biocomposite for bone tissue engineering and evaluation of gamma irradiation effect on its properties

    Energy Technology Data Exchange (ETDEWEB)

    Islam, Md. Minhajul [Department of Applied Chemistry and Chemical Engineering, Faculty of Engineering and Technology, University of Dhaka, Dhaka 1000 (Bangladesh); Khan, Mubarak A. [Institute of Radiation and Polymer Technology (IRPT), Atomic Energy Research Establishment (AERE), P. O. Box No. 3787, Dhaka 1000 (Bangladesh); Rahman, Mohammed Mizanur, E-mail: mizanur.rahman@du.ac.bd [Department of Applied Chemistry and Chemical Engineering, Faculty of Engineering and Technology, University of Dhaka, Dhaka 1000 (Bangladesh)

    2015-04-01

    Biodegradable porous hybrid polymer composites were prepared by using gelatin as base polymer matrix, β-tricalcium phosphate (TCP) and calcium sulfate (CS) as cementing materials, chitosan as an antimicrobial agent, and glutaraldehyde and polyethylene glycol (PEG) as crosslinkers at different mass ratios. Thereafter, the composites were subjected to γ-radiation sterilization. The structure and properties of these composite scaffolds were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), mechanical properties testing (compressive, bending, tensile and impact), thermogravimetry/differential thermal analysis (TG/DTA), and physical stability test in simulated body fluid (SBF). We found that TCP rich composites showed enhanced mechanical properties among all the crosslinked composites. γ-Radiation sterilization triggered further cross linking in polymer matrix resulting a decrease in pore size of the composites and an increase in pore wall thickness with improved mechanical and thermal properties. The chemically crosslinked composite with 40% TCP followed by γ-radiation sterilization showed the smallest pore size distribution with a mean pore diameter of 159.22 μm, which falls in the range of 100–350 μm — known to be suitable for osteoconduction. Considering its improved mechanical and thermal properties along with osteoconduction ability without cytotoxicity, we propose this biocomposite as a viable candidate for bone tissue engineering. - Highlights: • Composite scaffolds were prepared from biopolymers (gelatin and chitosan). • β-TCP and CS were used as bioactive cementing materials at different ratios. • γ-Sterilization improved the mechanical properties of the biocomposites. • γ-Sterilization reduced the cytotoxicity and induced high antimicrobial properties. • Composite having 40% TCP has the proper pore size distribution for osteoconduction.

  10. Preparation and Characterization of a Hydrophobic Metal-Organic Framework Membrane Supported on Thin Porous Metal Sheet

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jian; Canfield, Nathan L.; Liu, Wei

    2016-02-29

    A hydrophobic metal-organic framework (MOF) UiO-66-CH3 is prepared and its solvothermal stability is investigated in comparison to UiO-66. It is confirmed that the MOF stability is enhanced by introduction of the two methyl groups, while the water adsorption is reduced. Given its hydrophobicity and stability, UiO-66-CH3 is proposed as an attractive membrane material for gas separation under moisture conditions. The UiO-66-CH3 membrane is prepared on a 50µm-thin porous Ni support sheet for the first time by use of a secondary growth method. It is found that uniform seed coating on the support is necessary to form a continuous membrane. In addition to growth time and temperature, presence of a modulator in the growth solution is found to be useful for controlling hydrothermal membrane growth on the seeded support. A dense, inter-grown membrane layer is formed by 24-h growth over a temperature range from 120 oC to 160 oC. The membrane surface comprises 500 nm octahedral crystals, which are supposed to grow out of the original 100 nm spherical seeding crystals. The separation characteristics of resulting membranes are tested with pure CO2, air, CO2/air mixture, and humid CO2/air mixture. CO2 permeance as high as 1.9E-06 mol/m2/s/Pa at 31oC is obtained. Unlike the hydrophilic zeolite membranes, CO2 permeation through this membrane is not blocked by the presence of water vapor in the feed gas. The results suggest that this MOF framework is a promising membrane material worth to be further investigated for separation of CO2 and other small molecules from humid gas mixtures.

  11. 氮化硅基多孔陶瓷的制备技术、孔隙结构及其相关性能%Silicon Nitride Based Porous Ceramics:Preparation Technologies, Porous Structure and Properties

    Institute of Scientific and Technical Information of China (English)

    苏睿; 黄志锋; 李飞宇; 陈斐; 沈强

    2016-01-01

    氮化硅多孔陶瓷是近年来得到广泛关注的一类新型的结构-功能一体化陶瓷材料,在航空航天、机械、化工、海洋工程等重要领域有着广阔的应用前景。本文介绍了氮化硅基多孔陶瓷的主要制备技术,回顾了氮化硅基多孔陶瓷力学性能和介电性能的研究进展。考虑到高孔隙率氮化硅基多孔陶瓷力学性能难以提高,磷酸盐结合氮化硅基多孔陶瓷已经逐渐成为新的研究热点,因此,本文进一步对磷酸盐结合氮化硅基多孔陶瓷的制备技术、力学性能、介电性能、热学性能进行了综合评述,并对氮化硅基多孔陶瓷的应用前景进行了展望。%Silicon nitride porous ceramics is an advanced type of structure –function integration ceramic materials which is popular in recently, and it has profound application prospect in aerospace, machinery, chemistry, oceanographic engineering and other significant domain. In this article, the main preparation technologies of porous Si3N4 ceramics have been summarized, and the research progress about the mechanical and dielectric properties of porous Si3N4 ceramics have been reviewed in this paper. Further, consider about the problem that it is hard to improve the mechanical properties of porous Si3N4 ceramics with high porosity, the research hotspot is moving on porous Si3N4 ceramics with phosphate binder. Therefore, their preparation technologies, mechanical, dielectric and thermal properties have been analyzed in further, and the potential application of porous Si3N4 ceramics was discussed.

  12. Preparation of Desirable Porous Cell Structure Polylactide/Wood Flour Composite Foams Assisted by Chain Extender

    Directory of Open Access Journals (Sweden)

    Youyong Wang

    2017-08-01

    Full Text Available Polylactide (PLA/wood flour composite foam were prepared through a batch foaming process. The effect of the chain extender on the crystallization behavior and dynamic rheological properties of the PLA/wood flour composites were investigated as well as the crystal structure and cell morphology of the composite foams. The incorporation of the chain extender enhanced the complex viscosity and storage modulus of PLA/wood flour composites, indicating the improved melt elasticity. The chain extender also led to a decreased crystallization rate and final crystallinity of PLA/wood flour composites. With an increasing chain extender content, a finer and more uniform cell structure was formed, and the expansion ratio of PLA/wood flour composite foams was much higher than without the chain extender. Compared to the unfoamed composites, the crystallinity of the foamed PLA/wood flour composites was improved and the crystal was loosely packed. However, the new crystalline form was not evident.

  13. Spherically-clustered porous Au-Ag alloy nanoparticle prepared by partial inhibition of galvanic replacement and its application for efficient multimodal therapy.

    Science.gov (United States)

    Jang, Hongje; Min, Dal-Hee

    2015-03-24

    The polyvinylpyrrolidone (PVP)-coated spherically clustered porous gold-silver alloy nanoparticle (PVP-SPAN) was prepared by low temperature mediated, partially inhibited galvanic replacement reaction followed by silver etching process. The prepared porous nanostructures exhibited excellent photothermal conversion efficiency under irradiation of near-infrared light (NIR) and allowed a high payload of both doxorubicin (Dox) and thiolated dye-labeled oligonucleotide, DNAzyme (FDz). Especially, PVP-SPAN provided 10 times higher loading capacity for oligonucleotide than conventional hollow nanoshells due to increased pore diameter and surface-to-volume ratio. We demonstrated highly efficient chemo-thermo-gene multitherapy based on codelivery of Dox and FDz with NIR-mediated photothermal therapeutic effect using a model system of hepatitis C virus infected human liver cells (Huh7 human hepatocarcinoma cell line containing hepatitis C virus NS3 gene replicon) compared to conventional hollow nanoshells.

  14. Preparation of a new micro-porous poly(methyl methacrylate)-grafted polyethylene separator for high performance Li secondary battery

    Energy Technology Data Exchange (ETDEWEB)

    Gwon, Sung-Jin [Radiation Research Division for Industry and Environment, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup-si, Jeollabuk-do 580-185 (Korea, Republic of); Department of Materials Engineering, Chnugnam National University, Yuseong-gu, Daejeon 305-764 (Korea, Republic of); Choi, Jae-Hak; Sohn, Joon-Yong [Radiation Research Division for Industry and Environment, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup-si, Jeollabuk-do 580-185 (Korea, Republic of); Ihm, Young-Eon [Department of Materials Engineering, Chnugnam National University, Yuseong-gu, Daejeon 305-764 (Korea, Republic of); Nho, Young-Chang [Radiation Research Division for Industry and Environment, Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup-si, Jeollabuk-do 580-185 (Korea, Republic of)], E-mail: ycnho@kaeri.re.kr

    2009-10-01

    In this study, micro-porous poly(methyl methacrylate)-grafted polyethylene separators (PE-g-PMMA) were prepared by a radiation-induced graft polymerization of methyl methacrylate onto a conventional PE separator followed by a phase inversion. After the phase inversion, the micro-pores were generated in the grafted PMMA layer. The prepared micro-porous PE-g-PMMA separators showed an improved electrolyte uptake and ionic conductivity due to their improved affinity with a liquid electrolyte and the presence of pores in the grafted PMMA layer. The PE-g-PMMA separators exhibited a lower thermal shrinkage compared to the original PE separator. The PE-g-PMMA separators showed a better oxidation stability up to 5.0 V when compared to the original PE separator (4.5 V)

  15. Preparation of a new micro-porous poly(methyl methacrylate)-grafted polyethylene separator for high performance Li secondary battery

    Science.gov (United States)

    Gwon, Sung-Jin; Choi, Jae-Hak; Sohn, Joon-Yong; Ihm, Young-Eon; Nho, Young-Chang

    2009-10-01

    In this study, micro-porous poly(methyl methacrylate)-grafted polyethylene separators (PE-g-PMMA) were prepared by a radiation-induced graft polymerization of methyl methacrylate onto a conventional PE separator followed by a phase inversion. After the phase inversion, the micro-pores were generated in the grafted PMMA layer. The prepared micro-porous PE-g-PMMA separators showed an improved electrolyte uptake and ionic conductivity due to their improved affinity with a liquid electrolyte and the presence of pores in the grafted PMMA layer. The PE-g-PMMA separators exhibited a lower thermal shrinkage compared to the original PE separator. The PE-g-PMMA separators showed a better oxidation stability up to 5.0 V when compared to the original PE separator (4.5 V).

  16. Preparation of porous carboxymethyl chitosan grafted poly (acrylic acid) superabsorbent by solvent precipitation and its application as a hemostatic wound dressing.

    Science.gov (United States)

    Chen, Yu; Zhang, Yong; Wang, Fengju; Meng, Weiwei; Yang, Xinlin; Li, Peng; Jiang, Jianxin; Tan, Huimin; Zheng, Yongfa

    2016-06-01

    The volume phase transition of a hydrogel initiated by shrinking may result in complex patterns on its surface. Based on this unique property of hydrogel, we have developed a novel solvent precipitation method to prepare a kind of novel superabsorbent polymers with excellent hemostatic properties. A porous carboxymethyl chitosan grafted poly (acrylic acid) (CMCTS-g-PAA) superabsorbent polymer was prepared by precipitating CMCTS-g-PAA hydrogel with ethanol. Its potential application in hemostatic wound dressing was investigated. The results indicate that the modified superabsorbent polymer is non-cytotoxic. It showed a high swelling capacity and better hemostatic performance in the treatments of hemorrhage model of ear artery, arteria cruralis and spleen of the New Zealand white rabbit than the unmodified polymer and other commonly used clinic wound dressings. The hemostatic mechanism of the porous CMCTS-g-PAA polymer was also discussed.

  17. Porous Ti6Al4V scaffold directly fabricating by rapid prototyping: preparation and in vitro experiment

    NARCIS (Netherlands)

    Li, Jia Ping; Wijn, de Joost R.; Blitterswijk, van Clemens A.; Groot, de Klaas

    2006-01-01

    Three-dimensional (3D) fiber deposition (3DF), a rapid prototyping technology, was successfully directly applied to produce novel 3D porous Ti6Al4V scaffolds with fully interconnected porous networks and highly controllable porosity and pore size. A key feature of this technology is the 3D computer-

  18. 超细颗粒卤化银的制备与稳定性%PREPARATION OF ULTRA-FINE SILVER HALIDE PARTICLES AND THEIR STABILITY

    Institute of Scientific and Technical Information of China (English)

    崔兴品; 岳军

    1999-01-01

    With gelatin or gelatin+PVA as colloid protective medium and under proper reactive condition, ultra-fine silver iodobromide particles with average diameter of about 20 nm and better monodispersity were prepared by direct reaction of silver nitrate with mixture of potassium bromide and potassium iodide. According to TEM data, it was discovered that gelatin+PVA showed stronger colloid protective power for these ultra-fine particles, which restrained particles' coalescence and growth effectively during physical and chemical ripening, so that there was not observable change of particle size and monodispersity to be found. In the case of only gelatin as colloid protective medium to prepare ultra-fine silver iodobromide particles, particles'stability in the process of physical ripening depended on the ratio of gelatin amount to silver content as the preparing reaction. It appears that there exists a critical ratio of gelatin amount to silver content for particles′ stability. When experimental ratio of gelatin amount to silver content in the reaction was over this critical ratio, gelatin can protect ultra-fine particles against coalescence and growth to a considerable degree. On the contrary, the particle size beacme significantly large in the process of physical ripening due to decrease of gelatin protective power if the experimental ratio was lower than this critical ratio.

  19. Ion channel mimetic membranes and silica nanotubes prepared from porous aluminum oxide templates

    Science.gov (United States)

    Mitchell, David Tanner

    Chapter 1 provides background information on the template synthesis of nanomaterials. The template synthesis method is examined with special attention to the use of membranes containing monodisperse cylindrical pores as templates. Several examples of the utility of template-synthesized nanomaterials are given. The production of one type of template membrane, nanopore alumina, is reviewed. Reviews of sol-gel and silane chemistry are also provided. In Chapter 2, a sol-gel template synthesis process is used to produce silica nanotubes within the pores of alumina templates. The nanotubes can be modified using a variety of chemistries, typically via a silanization process. Because the nanotubes are formed in a template, the interior and exterior surface can be modified independently. Modified nanotubes can be used for drug detoxification or as extractants for the removal of metal ions. The nanotube surface can also be biotinylated, which causes binding to avidinated surfaces. Composite microtubes of silica and various polymers are also prepared. Additionally, Au nanowires are shown to assemble with colloidal Au particles using dithiols as linkers. Chapter 3 describes the attachment of proteins onto template-synthesized silica nanotubes. The proteins are covalently linked via an aldehyde silane bridge that binds to pendant primary amino moieties on the protein. Protein-modified nanotubes function as highly specific extractants. Avidin-modified nanotubes extract biotin-coated Au nanoparticles from solution with high extraction efficiency. Immunoprotein-modified nanotubes extract the corresponding antibody from solution with high specificity. Antibody-modified nanotubes extract one enantiomer from a racemic mix. Enzymes, including drug detoxification enzymes, were also attached to the nanotubes and were shown to retain their catalytic activity. Immunoproteins on the outside of nanotubes can be used to direct nanotube binding, creating specific labeling agents. Chapter 4

  20. Preparation of porous carboxymethyl chitosan grafted poly (acrylic acid) superabsorbent by solvent precipitation and its application as a hemostatic wound dressing

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yu, E-mail: cylsy@163.com [School of Material Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); Zhang, Yong [School of Life Science, Beijing Institute of Technology, Beijing 100081 (China); Wang, Fengju [School of Material Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); Meng, Weiwei; Yang, Xinlin [School of Life Science, Beijing Institute of Technology, Beijing 100081 (China); Li, Peng [School of Material Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); Jiang, Jianxin [State Key Laboratory of Trauma Burns and Combined Injury, The Third Military Medical University, Chongqing 400042 (China); Tan, Huimin [School of Material Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); Zheng, Yongfa [Guangdong Fuyang Biotechnology Co., Ltd., Heyuan, Guangdong 517000 (China)

    2016-06-01

    The volume phase transition of a hydrogel initiated by shrinking may result in complex patterns on its surface. Based on this unique property of hydrogel, we have developed a novel solvent precipitation method to prepare a kind of novel superabsorbent polymers with excellent hemostatic properties. A porous carboxymethyl chitosan grafted poly (acrylic acid) (CMCTS-g-PAA) superabsorbent polymer was prepared by precipitating CMCTS-g-PAA hydrogel with ethanol. Its potential application in hemostatic wound dressing was investigated. The results indicate that the modified superabsorbent polymer is non-cytotoxic. It showed a high swelling capacity and better hemostatic performance in the treatments of hemorrhage model of ear artery, arteria cruralis and spleen of the New Zealand white rabbit than the unmodified polymer and other commonly used clinic wound dressings. The hemostatic mechanism of the porous CMCTS-g-PAA polymer was also discussed. - Highlights: • The novel solvent precipitation method was developed to prepare the porous superabsorbent polymer. • The swelling rate was promoted and the harmful residual monomer was leached after modification. • The modified polymer showed good biological safety. • It showed good hemostasis to arterial hemorrhage model of the animal. • The hemostatic mechanism of the modified superabsorbent polymer was discussed.

  1. Preparation of Nano-Porous Activated Carbon Aerogel Using a Single-Step Activation Method for Use as High-Power EDLC Electrode in Organic Electrolyte.

    Science.gov (United States)

    Kwon, Soon Hyung; Kim, Bum-Soo; Kim, Sang-Gil; Lee, Byung-Jun; Kim, Myung-Soo; Jung, Ji Chul

    2016-05-01

    Carbon aerogel was chemically activated with KOH using two different activation methods (conventional activation method and single-step activation method) to yield the nano-porous activated carbon aerogel. Both nano-porous activated carbon aerogels exhibited a better capacitive behavior than carbon aerogel in organic electrolyte. However, a drastic decrease in the specific capacitance with increasing current density was observed in the ACA_C (activated carbon aerogel prepared by a conventional activation method), which is a general tendency of carbon electrode for EDLC in organic electrolyte. Interestingly, the specific capacitance of ACA_S electrode (activated carbon aerogel prepared by a single-step activation method) decreased slowly with increasing current density and its CV curve maintained a rectangular shape well even at a high scan rate of 500 mV/s. The enhanced electrochemical performance of ACA_S at a high current density was attributed to its low ionic resistance caused by the well-developed pore structure with appropriate pore size for easy moving of organic electrolyte ion. Therefore, it can be concluded that single-step activation method could be one of the efficient methods for preparation of nano-porous activated carbon aerogel electrode for high-power EDLC in organic electrolyte.

  2. Superhydrophilic porous TiO 2 film prepared by phase separation through two stabilizers

    Science.gov (United States)

    Huang, Weixin; Deng, Wei; Lei, Ming; Huang, Hong

    2011-03-01

    A novel method was developed to produce a TiO 2 film with circular pores on its surface. The pores aroused from the precursor solution using both acetylacetone (AcAc) and diethanolamine (DEA) as stabilizers. The appearance of interconnected or isolated pores for the films was discussed in relation to the phase separation in the sol-gel process with the presence of Acac and DEA. Macropore size, together with connectivity of pores and gel skeleton, can be controlled by selecting an appropriate composition for preparation at DEA amount or regulating a time scale of the sol-gel transition. Finally, wetting behavior of the resulting films was characterized by using contact angle measurements. The TiO 2 films with interconnected or relatively isolated pores exhibit superhydrophilic characteristic, although it is not exposed to ultraviolet irradiation. Deducing from the Wenzel-Cassie regimes' transition criterion, the existence of Cassie impregnating wetting regime rather than Wenzel one upon these porosity-driven superhydrophilic surfaces can be obtained.

  3. Preparation of alumina nanoshell coated porous silica spheres for inorganic anions separation.

    Science.gov (United States)

    Song, Zhihua; Wu, Dapeng; Ding, Kun; Guan, Yafeng

    2016-02-12

    It had been reported that alumina nanoshell coating could be obtained on the external surface of various substrates in one-nanometer precision in aqueous solution. In this work, alumina nanoshell coated mesoporous silica microbeads (nanoAl2O3/mesoSiO2) were prepared with the similar method, and were successfully applied to inorganic anions separation. As the mass transfer speed is largely constrained in the mesopore compared with that on the open surface, it was found that a complete alumina nanoshell coating could be obtained within the mesopore until the five-time coating was carried out. After characterization by BET, SEM and FTIR, it was found that the obtained nanoAl2O3/mesoSiO2 particles are smooth and well dispersed, and the mesopores are well reserved. In addition, the full coverage of nanoAl2O3 shell in mesopores was also confirmed by the binding capacity experiments with berberine. Finally, the nanoAl2O3/mesoSiO2 particles were packed in silica capillary for the separation of inorganic anions I(-), SCN(-), Br(-), NO2(-) and NO3(-) with ion chromatography (IC), and a column efficiency of 3.8 × 10(4) plates per meter was obtained for I(-).

  4. A simple preparation of carbon doped porous Bi{sub 2}O{sub 3} with enhanced visible-light photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Dai, Gaopeng, E-mail: dgp2000@126.com [Department of Chemical Engineering and Food Science, Hubei University of Arts and Science, Xiangyang 441053 (China); Hubei Key Laboratory of Low Dimensional Optoelectronic Materials and Devices, Xiangyang 441053 (China); Liu, Suqin [Department of Chemical Engineering and Food Science, Hubei University of Arts and Science, Xiangyang 441053 (China); Hubei Key Laboratory of Low Dimensional Optoelectronic Materials and Devices, Xiangyang 441053 (China); Liang, Ying [Department of Chemical Engineering and Food Science, Hubei University of Arts and Science, Xiangyang 441053 (China)

    2014-09-01

    Graphical abstract: Carbon doped bismuth oxide with a porous structure was prepared by calcination of bismuth nitrate in glycol solution. The as-prepared samples show enhanced visible-light photocatalytic activity. - Highlights: • C-doped Bi{sub 2}O{sub 3} with a porous structure is obtained by a simply calcination of Bi(NO{sub 3}){sub 3} in glycol. • The C-doped Bi{sub 2}O{sub 3} exhibited much higher photocatalytic activity than the pure Bi{sub 2}O{sub 3}. • Carbon was incorporated into the lattice of Bi{sub 2}O{sub 3} lattice. - Abstract: Carbon doped bismuth oxide (Bi{sub 2}O{sub 3}) with a porous structure is obtained by a simply calcination of bismuth nitrate pentahydrate (Bi(NO{sub 3}){sub 3}⋅5H{sub 2}O) in glycol solution. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and UV–Vis absorption spectroscopy. The photocatalytic activity was evaluated by the photocatalytic degradation of methyl orange (MO) in an aqueous solution under visible-light radiation (λ > 420 nm). The results show that carbon was incorporated into the lattice of Bi{sub 2}O{sub 3}. The absorption intensity of C-doped Bi{sub 2}O{sub 3} increases in the region of 450–530 nm and the absorption edge has an obvious shift to long wavelength. The C-doped Bi{sub 2}O{sub 3} exhibited much higher photocatalytic activity than the pure one due to the synergetic effects of the porous structure and the improved absorption in the visible-light region.

  5. Preparation of reaction-bonded porous silicon carbide with denser surface layer in one-pot process

    National Research Council Canada - National Science Library

    SHIMAMURA, Akihiro; FUKUSHIMA, Manabu; HOTTA, Mikinori; OHJI, Tatsuki; KONDO, Naoki

    2015-01-01

    Macro-porous silicon carbide with high porosity around 70 vol %, comprising micrometer-sized spherical porosities and a relatively denser surface layer, was fabricated by a direct blowing and reaction bonding method...

  6. Preparation of reaction-bonded porous silicon carbide with denser surface layer in one-pot process

    National Research Council Canada - National Science Library

    Akihiro SHIMAMURA; Manabu FUKUSHIMA; Mikinori HOTTA; Tatsuki OHJI; Naoki KONDO

    2015-01-01

      Macro-porous silicon carbide with high porosity around 70 vol %, comprising micrometer-sized spherical porosities and a relatively denser surface layer, was fabricated by a direct blowing and reaction bonding method...

  7. Preparation of porous TiO2/ZnO composite film and its photocathodic protection properties for 304 stainless steel

    Science.gov (United States)

    Xu, Hongmei; Liu, Wei; Cao, Lixin; Su, Ge; Duan, Ruijing

    2014-05-01

    TiO2/ZnO composite films with porous structure were prepared on the 304 stainless steel (304SS) by the sol-gel method and heating treatment. The crystalline phase and morphology of as-prepared TiO2/ZnO composite films were characterized systematically by X-ray diffraction (XRD), scanning electron microscope (SEM) and ultraviolet-visible (UV-vis) spectroscopy, respectively. The influences of Ti/Zn molar ratio and the annealing temperature on the photoelectric property of the samples have been investigated and their photocathodic protection performances for 304 stainless steel under dark and UV conditions have also been evaluated in 3.0% NaCl solution by the electrochemical measurements. The results indicate that porous TiO2/ZnO composite film has a great enhancement of the light absorption and photoelectric property under UV illumination. This can be ascribed to the mutual effect of TiO2/ZnO heterojunctions and the porous structures in the composite films, which provide a better photogenerated cathodic protection for 304SS.

  8. Micro-PIXE and micro-RBS characterization of micropores in porous silicon prepared using microwave-assisted hydrofluoric acid etching.

    Science.gov (United States)

    Ahmad, Muthanna; Grime, Geoffrey W

    2013-04-01

    Porous silicon (PS) has been prepared using a microwave-assisted hydrofluoric acid (HF) etching method from a silicon wafer pre-implanted with 5 MeV Cu ions. The use of microbeam proton-induced X-ray emission (micro-PIXE) and microbeam Rutherford backscattering techniques reveals for the first time the capability of these techniques for studying the formation of micropores. The porous structures observed from micro-PIXE imaging results are compared to scanning electron microscope images. It was observed that the implanted copper accumulates in the same location as the pores and that at high implanted dose the pores form large-scale patterns of lines and concentric circles. This is the first work demonstrating the use of microwave-assisted HF etching in the formation of PS.

  9. Preparation and properties of gel membrane containing porous PVDF-HFP matrix and cross-linked PEG for lithium ion conduction

    Institute of Scientific and Technical Information of China (English)

    Mei ZHANG; Aiqing ZHANG; Zhenyu CUI; Baoku ZHU; Gaigc HAN; Youyi XU

    2008-01-01

    Lithium ion conducting membranes are the key materials for lithium batteries. The lithium ion conducting gel polymer electrolyte membrane (Li-GPEM) based on porous poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) matrix and cross-linked PEG network is pre-pared by a typical phase inversion process. By immersing the porous PVDF-HFP membrane in liquid electrolyte con-taining poly(ethylene glycol) diacrylate (PEGDA) and an initiator to absorb the liquid electrolyte at 25℃, and then thermally cross-linking at 60℃, the Li-GPEM is fabricated successfully. The measurements on its weight loss, mech-anical and electrochemical properties reveal that the obtained Li-GPEM has better overall performance than the liquid and blend gel systems used as conductive media in lithium batteries. The ionic conductivity of the fabricated Li-GPEM can reach as high as 2.25 × 10-3S/cm at 25℃.

  10. Tin nanoparticles encapsulated in porous multichannel carbon microtubes: preparation by single-nozzle electrospinning and application as anode material for high-performance Li-based batteries.

    Science.gov (United States)

    Yu, Yan; Gu, Lin; Zhu, Changbao; van Aken, Peter A; Maier, Joachim

    2009-11-11

    Tin nanoparticles encapsulated in porous multichannel carbon microtubes (denoted as SPMCTs) were prepared by carbonization of electrospun PAN-PMMA-tin octoate nanofibers fabricated using a single-nozzle electrospinning technique. This material exhibited excellent characteristics for lithium ion battery anode applications in terms of reversible capacities, cycling performance, and rate capability. Undertaking such a production configuration allows the long-existing problem of obtaining a high packing density of tin particles while retaining sufficient spare space to buffer the volume variation during lithium alloying and dealloying processes to be properly addressed. Furthermore, the porous carbon shell preserves both the mechanical and chemical stability of the function-active Sn metal, which also serves as a highly conductive medium allowing Li(+) to access.

  11. Discussion on the Production Process of Porous Fine Denier PA66 Draw Texturing Yarn%锦纶66细旦多孔弹力丝生产工艺探讨

    Institute of Scientific and Technical Information of China (English)

    周兆莲; 林飞; 周伟

    2011-01-01

    Production technology of porous fine denier PA66 draw textured yarn by the POY-DTY process is introduced. Discussions are made on the polymer chip selection and drying, spinning temperature, spinning hole diameter, thread cooling, false-draw twisting, etc.%采用锦纶66 POY-DTY生产工艺生产dpf<1.2 dtex的细旦多孔弹力丝,主要讨论POY的切片选择、切片干燥、纺丝温度、喷丝孔径、丝束冷却等工艺,简要介绍了DTY的拉伸假捻工艺.

  12. Fine granules showing sustained drug release prepared by high-shear melt granulation using triglycerin full behenate and milled microcrystalline cellulose.

    Science.gov (United States)

    Aoki, Hajime; Iwao, Yasunori; Uchimoto, Takeaki; Noguchi, Shuji; Kajihara, Ryusuke; Takahashi, Kana; Ishida, Masayuki; Terada, Yasuko; Suzuki, Yoshio; Itai, Shigeru

    2015-01-30

    This study aimed to prepare fine granules with a diameter less than 200μm and sustained drug release properties by melt granulation. Triglycerin full behenate (TR-FB) was examined as a new meltable binder (MB) by comparison of its properties with those of glycerin monostearate (GM), widely used as MB. The effect of milling microcrystalline cellulose (MCC), an excipient for melt granulation, on the granule properties was also investigated. TR-FB was more stable during heating and storage than GM, and produced smaller granules with narrower particle size distribution, larger yield in the 106-200μm range, uniform roundness and better sustained drug release profile than those prepared with GM. Granules prepared with milled MCC had almost the same physicochemical properties as those produced with intact MCC. However, milled MCC produced granules with a more rigid structure and smaller void space than intact MCC. Consequently, the granules produced with milled MCC showed better sustained drug release behavior than those prepared with intact MCC. We successfully prepared fine granules with sustained drug release properties and diameter of less than 200μm using TR-FB and milled MCC. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Selective acetone gas sensors using porous WO{sub 3}-Cr{sub 2}O{sub 3} thin films prepared by sol-gel method

    Energy Technology Data Exchange (ETDEWEB)

    Gao Peng; Ji Huiming, E-mail: jihuiming@tju.edu.cn; Zhou Yugui; Li Xiaolei

    2012-01-31

    WO{sub 3}-Cr{sub 2}O{sub 3} semiconducting thin films were prepared by sol-gel method. Acetone gas sensing properties were investigated. Monoclinic phase was obtained as determined by X-ray diffraction after WO{sub 3}-Cr{sub 2}O{sub 3} films were sintered in oxygen atmosphere for 1 h at 500 Degree-Sign C (quenched after sintering). Porous structure was observed by using field emission scanning electron microscopy. Electrical properties were studied by conductivity measurement. The acetone vapor sensing properties of these thin films were found strongly influenced by the porous structure, the content of Cr{sub 2}O{sub 3}, the sintering temperature, and the cooling way. As-prepared WO{sub 3}-Cr{sub 2}O{sub 3} thin films exhibit excellent acetone vapor sensing properties with the maximum sensitivity {approx} 8.91 at 320 Degree-Sign C in air atmosphere with fast response and recovery time. - Highlights: Black-Right-Pointing-Pointer Porous structure was prepared to improve the thin film's gas-sensing properties. Black-Right-Pointing-Pointer Dissymmetrical monoclinic structure was obtained to improve selectivity to acetone. Black-Right-Pointing-Pointer Quenching after sintering enables obtain dissymmetrical structure. Black-Right-Pointing-Pointer Effects of the sintering temperature and the Cr{sub 2}O{sub 3} content were discussed. Black-Right-Pointing-Pointer As prepared sensors can diagnose diabetes based on human breath analysis.

  14. Kaolinite as a Suspending Agent for Preparation of Porous BaTiO3 Ceramics via Freeze Casting

    Science.gov (United States)

    Li, Pin; Pu, Yongping; Dong, Zijing; Gao, Pan

    2014-02-01

    Porous barium titanate (BT) ceramics were fabricated by a freeze-casting technique with kaolinite as a suspending agent, and the effects of the kaolinite content on the microstructure and dielectric properties were investigated. The porous BT ceramics possessed high porosity and a unique two-dimensional pore structure along the freezing direction. The absolute value of the zeta potential and the viscosity of the slurry increased with increasing kaolinite content. The zeta potential plot and viscosity characterization results showed that a stable slurry was obtained when the kaolinite content was 8 wt.%. The porosity was substantially affected by the suspension effect and the fluxing action of the kaolinite. Porosity characterization showed that the porosity of the porous BT ceramic reached a maximum value for 8 wt.% addition of kaolinite. Scanning electron microscopy showed that the porous BT ceramics possessed a multilayered channel structure. The temperature dependence of the permittivity showed that the porous BT ceramics possessed good temperature stability of the dielectric constant.

  15. Preparation and characterization of porous bioceramic layers on pure titanium surfaces obtained by micro-arc oxidation process

    Science.gov (United States)

    Chien, Chi-Sheng; Hung, Yu-Chien; Hong, Ting-Fu; Wu, Chung-Chun; Kuo, Tsung-Yuan; Lee, Tzer-Min; Liao, Tze-Yuan; Lin, Huan-Chang; Chuang, Cheng-Hsin

    2017-03-01

    Fluorapatite (FA) has better chemical and thermal stability than hydroxyapatite (HA), and has thus attracted significant interest for biomaterial applications in recent years. In this study, porous bioceramic layers were prepared on pure titanium surfaces using a micro-arc oxidation (MAO) technique with an applied voltage of 450 V and an oxidation time of 5 min. The MAO process was performed using three different electrolyte solutions containing calcium fluoride (CaF2), calcium acetate monohydrate (Ca(CH3COO)2·H2O), and sodium phosphate monobasic dihydrate (NaH2PO4·2H2O) mixed in ratios of 0:2:1, 1:1:1, and 2:0:1, respectively. The surface morphology, composition, micro-hardness, porosity, and biological properties of the various MAO coatings were examined and compared. The results showed that as the CaF2/Ca(CH3COO)2·H2O ratio increased, the elemental composition of the MAO coating transformed from HA, A-TiO2 (Anatase) and R-TiO2 (Rutile); to A-TiO2, R-TiO2, and a small amount of HA; and finally A-TiO2, R-TiO2, CaF2, TiP2O5, and FA. The change in elemental composition was accompanied by a higher micro-hardness and a lower porosity. The coatings exhibited a similar in vitro bioactivity performance during immersion in simulated body fluid for 7-28 days. Furthermore, for in initial in vitro biocompatibility tests performed for 24 h using Dulbecco's Modified Eagle Medium (DMEM) supplement containing 10%Fetal bovine serum, the attachment and spreading of osteoblast-like osteosarcoma MG63 cells were found to increase slightly with an increasing CaF2/Ca(CH3COO)2·H2O ratio. In general, the results presented in this study show that all three MAO coatings possess a certain degree of in vitro bioactivity and biocompatibility.

  16. 多孔TiO2薄膜的制备研究进展%Progress in Preparation Methods of Porous TiO2 Thin Films

    Institute of Scientific and Technical Information of China (English)

    王达; 刘建敏; 周曦亚

    2011-01-01

    The preparation methods of porous TiO2 thin films,such as liquid phase ways (Including sol-gel, evaporation-induced self-assembly,etc. ), physical vapor deposition waysdncluding magnetron sputtering, electron beam evaporation deposition,etc. .), electrochemical ways (Including anodic oxidation, micro-arc oxidation,etc. ) are summarized, and the preparing theory is introduced respectively. Different ways of preparing porous TiO2 thin films have great difference in surface topography, aperture size, tropism and wall of hole thickness aspect. The problems in synthesizing porous TiO2 thin films and research direction in the future are pointed out at last.%综述了液相法(包括溶胶凝胶法、蒸发诱导自组装法等)、电化学法(包括阳极氧化法、微弧氧化法等)、物理气相法(包括磁控溅射法、电子束蒸发法等)、化学气相法等制备多孔TiO2薄膜的方法,介绍了相应的合成原理,指出不同方法制备的多孔TiO2薄膜在表面形貌、孔径尺寸、取向和孔壁厚度等方面存在很大差异.通过对比不同制备方法的优缺点并结合工业化生产成本,提出了今后多孔TiO2薄膜制备技术的发展方向,并展望了多孔TiO2薄膜广阔的应用前景.

  17. Measurement of Electrical Conductivity of Porous Titanium and Ti6Al4V Prepared by the Powder Metallurgy Method

    Institute of Scientific and Technical Information of China (English)

    ZHU Ke; LI Cheng-Feng; ZHU Zhen-Gang

    2007-01-01

    @@ Porous titanium and Ti6Al4V are produced by the powder metallurgy method. Dependence of the electrical conductivity on the porosity and pore size is investigated and the experimental results are correlative and compared with several earlier models. A newly modified Mori-Tanaka relationship based on the effective field method is proposed, which is successfully applied to describe the dependence of the electrical conductivity of porous titanium and Ti6Al4V on the porosity. The pore size has a minor effect on the electrical conductivity of both samples.

  18. Phase composition, microstructure, and mechanical properties of porous Ti-Nb-Zr alloys prepared by a two-step foaming powder metallurgy method.

    Science.gov (United States)

    Rao, X; Chu, C L; Zheng, Y Y

    2014-06-01

    Porous Ti-Nb-Zr alloys with different porosities from 6.06 to 62.8% are prepared by a two-step foaming powder metallurgy method using TiH2, Nb, and Zr powders together with 0 to 50wt% of NH4HCO3. The effects of the amounts of Nb and Zr as well as the sintering temperature (1473 to 1673K) on their phase composition, porosity, morphology, and mechanical characteristics are investigated. By controlling the porosity, Nb and Zr concentrations as well as the sintering temperature, porous Ti-Nb-Zr alloys with different mechanical properties can be obtained, for example, the hardness between 290 and 63HV, the compressive strength between 1530.5 and 73.4MPa, and the elastic modulus between 10.8 and 1.2GPa. The mechanical properties of the sintered porous Ti-Nb-Zr alloys can be tailored to match different requirements for the human bones and are thus potentially useful in the hard tissue implants. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Preparation of Porous F-WO3/TiO2 Films with Visible-Light Photocatalytic Activity by Microarc Oxidation

    Directory of Open Access Journals (Sweden)

    Chung-Wei Yeh

    2012-01-01

    Full Text Available Porous F-WO3/TiO2 (mTiO2 films are prepared on titanium sheet substrates using microarc oxidation (MAO technique. The X-ray diffraction patterns show that visible-light (Vis enabling mTiO2 films with a very high content of anatase TiO2 and high loading of WO3 are successfully synthesized at a low applied voltage of 300 V using electrolyte contenting NaF and Na2WO4 without subsequent heat treatment. The cross-sectional transmission electron microscopy micrograph reveals that the mTiO2 films feature porous networks connected by many micron pores. The diffused reflection spectrum displays broad absorbance across the UV-Vis regions and a significant red shift in the band gap energy (∼2.23 eV for the mTiO2 film. Owing to the high specific surface area from the porous microstructure, the mTiO2 film shows a 61% and 50% rate increase in the photocatalytic dye degradation, as compared with the N,C-codoped TiO2 films under UV and Vis irradiation, respectively.

  20. Preparation and characterization of porous granular ceramic containing dispersed aluminum and iron oxides as adsorbents for fluoride removal from aqueous solution.

    Science.gov (United States)

    Chen, Nan; Zhang, Zhenya; Feng, Chuanping; Zhu, Dirui; Yang, Yingnan; Sugiura, Norio

    2011-02-15

    Porous granular ceramic adsorbents containing dispersed aluminum and iron oxides were synthesized by impregnating with salt solutions followed by precipitation at 600°C. In the present work detailed studies were carried out to investigate the effect of contact time, adsorbent dose, initial solution pH and co-existing anions. Characterization studies on the adsorbent by SEM, XRD, EDS, and BET analysis were carried out to clarify the adsorption mechanism. The adsorbents were sphere in shape, 2-3mm in particle size, highly porous and showed specific surface area of 50.69 sq m/g. The fluoride adsorption capacity of prepared adsorbent was 1.79 mg/g, and the maximum fluoride removal was obtained at pH 6. Both the Langmuir and Freundlich isotherm models were found to represent the measured adsorption data well. The experimental data were well explained with pseudo-second-order kinetic model. Results from this study demonstrated potential utility of Al/Fe dispersed in porous granular ceramics that could be developed into a viable technology for fluoride removal from aqueous solution. Copyright © 2010 Elsevier B.V. All rights reserved.

  1. Porous NiTi shape memory alloys prepared by thermal explosion method%热爆法制备多孔NiTi形状记忆合金

    Institute of Scientific and Technical Information of China (English)

    李强; 于景媛; 李晓东; 孙旭东; 白华; 李然

    2006-01-01

    Thermal explosion method was used to prepare porous NiTi shape memory alloy. The process of thermal explosion was investigated. The effect of process parameters on thermal explosion reaction and properties of products was analyzed. The results showed heating rate, green density, particle size of initial powder strongly affected combustion temperature, porosity and compressive strength of final products. The mechanism of thermal explosion and the microstructure of reacted products were studied by XRD and SEM photographs. The results showed the final products mainly comprised of NiTi, Ti2Ni and TiNi3 phases and theirstrength decreased with the increase of porosity.

  2. PREPARATION OF CARBON NANOFIBERS BY POLYMER BLEND TECHNIQUE

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The polymer blend technique is a novel method to produced carbon nanofibers. In this paper, we have prepared fine carbon fibers and porous carbon materials by this technique, and we will discuss the experiment results by means of SEM, TGA, Element Analysis, etc.

  3. 多孔碳柱撑膨润土的制备与表征%PREPARATION AND CHARACTERIZATION OF POROUS CARBON PILLARED BENTONITE

    Institute of Scientific and Technical Information of China (English)

    张增志; 杨春卫; 牛俊杰

    2008-01-01

    Porous carbon pillared bentonite was prepared from bentonite modified by C19H42BrN and C10H16CIN. The porous pillared bentonite were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, nitrogen absorption/desorption, thermal-gravimetric analysis and differential scanning calorimetry. The influence of organic modifier on the characteristics of porous pillared bentonite was investigated. The results show that organic modifier combines with bentonite particles by covalent bond and ion embedding. The microstructure of porous carbon pillared bentonite looks like needle slice. The most probable pore size distribution is about 1.7 nm. The modifier slice mainly consists of two direction holes supported by a carbonization pillar. The high-temperature stability of carbon pillared bentonite was improved.%用十六烷基三甲基溴化铵和苄基三甲基氯化铵改性膨润土制备了多孔碳柱撑膨润土.用Fourier变换红外光谱仪、扫描电子显微镜和氮气吸附-脱附、热分析系统地研究了有机改性剂对多孔材料性能的影响.结果表明:膨润土微粒与有机改性剂以共价键和离子嵌入2种形式结合;多孔碳柱撑膨润土的微观形貌呈针片状,最可几孔径分布大约在1.7nm;多孔材料的主要结构是由碳化的大粒子柱撑而构建的二维孔径,烧结后的有机黏土热稳定性大大提高.

  4. A study on preparation of PTFE fine powder from its dispersions%从聚四氟乙烯分散液制备微粉的研究

    Institute of Scientific and Technical Information of China (English)

    龚天龙; 余自力

    2014-01-01

    Polytetrafluoroethylene( PTFE) fine powder was prepared from its dispersions by destroying the pH balance. The obtained PTFE fine powder was found to have molecular weight in the order of 107 ,median diameter D50 of 25 μm,and has the same struc-ture as commercial PTFE.%本文以聚四氟乙烯( PTFE)分散液(乳液)为原料,利用破坏其酸碱平衡的原理,成功地制备了PTFE微粉。所得到PTFE微粉分子量达到107数量级,中值粒径D50为25μm,树脂结构与PTFE一致。

  5. Clarithromycin highly-loaded gastro-floating fine granules prepared by high-shear melt granulation can enhance the efficacy of Helicobacter pylori eradication.

    Science.gov (United States)

    Aoki, Hajime; Iwao, Yasunori; Mizoguchi, Midori; Noguchi, Shuji; Itai, Shigeru

    2015-05-01

    In an effort to develop a new gastro-retentive drug delivery system (GRDDS) without a large amount of additives, 75% clarithromycin (CAM) loaded fine granules were prepared with three different hydrophobic binders by high-shear melt granulation and their properties were evaluated. Granules containing the higher hydrophobic binder showed sustained drug release and were able to float over 24h. The synchrotron X-ray CT measurement indicated that both the high hydrophobicity of the binder and the void space inside the granules might be involved in their buoyancy. In an in vivo experiment, the floating granules more effectively eradicated Helicobacter pylori than a CAM suspension by remaining in the stomach for a longer period. In short, CAM highly-loaded gastro-floating fine granules can enhance the eradication efficiency of H. pylori compared with CAM alone. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Effects of heat treatment on characteristics of porous Ni-rich NiTi SMA prepared by SHS technique

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The effects of heat treatment on the microstructure and compressive properties of porous Ni-rich NiTi shape memory alloy (SMA) fabricated by self-propagating high-temperature synthesis (SHS) were investigated. The solution treatment at 1050℃ has little effects on stable Ti2Ni second phase, however, it decreases the amount of Ni4Ti3 phase derived from the SHS process and results in the improvement of the ductility of porous NiTi SMA. The subsequent aging treatment after solution treatment could lead to the precipitation of the discrete Ni4Ti3 phase in NiTi matrix grains, which increases the brittleness of porous NiTi SMA. Porous NiTi SMA presents a composite fracture behavior consisting of a ductile fracture of NiTi matrix and a cleavage fracture of second phase particles. Many cracks existing on the interfaces indicate that the bonding of the matrix with second phase particles is weak.

  7. Preparation of Au-Pd bimetallic nanoparticles in porous germania nanospheres: A study of their morphology and catalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Regan, Maureen R. [Department of Chemistry, Fordham University, 441, East Fordham Road, Bronx, NY 10458 (United States); Banerjee, Ipsita A. [Department of Chemistry, Fordham University, 441, East Fordham Road, Bronx, NY 10458 (United States)]. E-mail: banerjee@fordham.edu

    2006-03-15

    Size controlled Au-Pd bimetallic nanoparticles with an average size of 7-10 nm were grown in porous germania nanospheres. The properties of the resulting nanocomposites were characterized by electron microscopy, energy dispersive spectroscopy, and ultraviolet-visible spectroscopy. The catalytic activity of the nanocomposites was also examined by studying the degradation of p-nitroaniline.

  8. Waste-to-resource preparation of a porous ceramic membrane support featuring elongated mullite whiskers with enhanced porosity and permeance

    NARCIS (Netherlands)

    Zhu, Li; Dong, Yingchao; Hampshire, Stuart; Cerneaux, Sophie; Winnubst, Aloysius J.A.

    2015-01-01

    Different from traditional particle packing structure, a porous structure of ceramic membrane support was fabricated, featuring elongated mullitewhiskers with enhanced porosity, permeance and sufficient mechanical strength. The effect of additives (MoO3and AlF3) and sintering procedureon open porosi

  9. Potential use of porous titanium-niobium alloy in orthopedic implants: preparation and experimental study of its biocompatibility in vitro.

    Directory of Open Access Journals (Sweden)

    Jian Xu

    Full Text Available BACKGROUND: The improvement of bone ingrowth into prosthesis and enhancement of the combination of the range between the bone and prosthesis are important for long-term stability of artificial joints. They are the focus of research on uncemented artificial joints. Porous materials can be of potential use to solve these problems. OBJECTIVES/PURPOSES: This research aims to observe the characteristics of the new porous Ti-25Nb alloy and its biocompatibility in vitro, and to provide basic experimental evidence for the development of new porous prostheses or bone implants for bone tissue regeneration. METHODS: The Ti-25Nb alloys with different porosities were fabricated using powder metallurgy. The alloys were then evaluated based on several characteristics, such as mechanical properties, purity, pore size, and porosity. To evaluate biocompatibility, the specimens were subjected to methylthiazol tetrazolium (MTT colorimetric assay, cell adhesion and proliferation assay using acridine staining, scanning electron microscopy, and detection of inflammation factor interleukin-6 (IL-6. RESULTS: The porous Ti-25Nb alloy with interconnected pores had a pore size of 200 µm to 500 µm, which was favorable for bone ingrowth. The compressive strength of the alloy was similar to that of cortical bone, while with the elastic modulus closer to cancellous bone. MTT assay showed that the alloy had no adverse reaction to rabbit bone marrow mesenchymal stem cells, with a toxicity level of 0 to 1. Cell adhesion and proliferation experiments showed excellent cell growth on the surface and inside the pores of the alloy. According to the IL-6 levels, the alloy did not cause any obvious inflammatory response. CONCLUSION: All porous Ti-25Nb alloys showed good biocompatibility regardless of the percentage of porosity. The basic requirement of clinical orthopedic implants was satisfied, which made the alloy a good prospect for biomedical application. The alloy with 70

  10. Preparation of Porous Arrowroot Starch by Double Enzymatic Hydrolysis%复合酶法制备葛根多孔淀粉

    Institute of Scientific and Technical Information of China (English)

    江慧娟; 黄赣辉

    2011-01-01

    Porous arrowroot starch was prepared by simultaneous hydrolysis with α-amylase and glucoamylase.The effects of enzyme dosage,glucoamylase-to-α-amylase ratio,pH,hydrolysis time and hydrolysis temperature on the oil-absorbing capacity of porous arrowroot starch were investigated.The optimal hydrolysis conditions for preparing porous arrowroot starch were determined by orthogonal array design method to be 3:1 glucoamylase-to-α-amylase ratio,0.6% total enzyme amount,pH 5.0,12 h hydrolysis time and 50 ℃ hydrolysis temperature.Under these conditions,the maximum oil-absorbing rate of 3:1 and excellent pore formation were achieved.%使用α-淀粉酶与糖化酶复合制备葛根多孔淀粉。通过单因素试验,对多孔淀粉吸油率进行考察,研究其品质特性随加酶量、酶配比、pH值、酶解时间和酶解温度等变化的规律。并由正交试验得出最佳工艺条件,当加酶量0.6%、酶解时间12h、pH5.0、酶解温度50℃、酶质量比(糖化酶:α-淀粉酶)3:1时吸油率最高(60%),且成孔效果良好。

  11. Study on Preparation and Properties of Porous Starch%多孔淀粉的制备及性能研究

    Institute of Scientific and Technical Information of China (English)

    尹卓林; 解乐福; 李艳杰; 马烽

    2013-01-01

    以玉米淀粉为原料,采用复合酶解法制备玉米多孔淀粉,考察了酶用量、酶配比、反应时间、反应温度、淀粉浓度以及pH值对多孔淀粉吸附性能的影响。通过单因素实验确定了制备玉米多孔淀粉的优化条件为:酶用量为1.2%,酶配比为1∶2,反应温度为55℃,反应时间为12 h,pH为6.0,淀粉的浓度为30%。制备得到的多孔淀粉吸油率达到82.14%,远远高于原淀粉,吸附性能良好。%Using corn starch as raw material , corn porous starch was prepared by enzyme hydrolysis method.Its parameters, such as enzyme concentration , the ratio of enzyme, reaction time, reaction temperature , starch concentration , and pH conditions were investigated .The optimal conditions for preparation of porous corn starch were determined by single factor experiment .The optimal conditions were enzyme concentration 1.2%,enzyme ratio 1∶2,the reaction temperature 55℃,the reaction time 12 h,the starch concentration 30%and pH 6.0.The oil absorption ratio of porous starch was 82.14%,far higher than the original starch adsorption performance .

  12. Preparation and In Vitro/In Vivo Characterization of Porous Sublingual Tablets Containing Ternary Kneaded Solid System of Vinpocetine with β-Cyclodextrin and Hydroxy Acid

    Science.gov (United States)

    Aburahma, Mona H.; El-Laithy, Hanan M.; Hamza, Yassin El-Said

    2010-01-01

    The demand for sublingual tablets has been growing during the previous decades especially for drugs with extensive hepatic first-pass metabolism. Vinpocetine, a widely used neurotropic agent, has low oral bioavailability due to its poor aqueous solubility and marked first-pass metabolism. Accordingly, the aim of this work was to develop tablets for the sublingual delivery of vinpocetine. Initially, the feasibility of improving vinpocetine’s poor aqueous solubility by preparing kneaded solid systems of the drug with β-Cyclodextrin and hydroxy acids (citric acid and tartaric acid) was assessed. The solid system with improved solubility and dissolution properties was incorporated into porous tablets that rapidly disintegrate permitting fast release of vinpocetine into the sublingual cavity. The pores were induced into these tablets by directly compressing the tablets’ excipients with a sublimable material, either camphor or menthol, which was eventually sublimated leaving pores. The obtained results demonstrated that the tablets prepared using camphor attained sufficient mechanical strength for practical use together with rapid disintegration and dissolution. In vivo absorption study performed in rabbits indicated that the sublingual administration of the proposed porous tablets containing vinpocetine solid system with β-Cyclodextrin and tartaric acid could be useful for therapeutic application. PMID:21179352

  13. Preparation and formation mechanism of porous carbon nanosheets by thermal decomposition of polyvinyl alcohol films impregnated with zinc (II) and nitrate ions

    Science.gov (United States)

    Hattori, Yoshiyuki; Kojima, Rikio; Sagisaka, Kento; Umeda, Motoki; Tanaka, Toshihisa; Kondo, Atsushi; Iiyama, Taku; Kimura, Mutsumi; Fujimoto, Hiroyuki; Touhara, Hidekazu

    2017-03-01

    Porous carbon nanosheets (PCNS) with high surface areas were prepared by thermal decomposition of polyvinyl alcohol (PVA) films impregnated with Zn2+ and NO3-. Through this simple preparation method that required no additional activation processes, curved carbon nanosheets (1600 m2 g-1) and bimodal pore structure consisting of micropores and mesopores. Because of their unique structural properties, the PCNS are attractive for use as electrode materials. The electrode performance of the PCNS was investigated in 1-M tetraethylammonium tetrafluoroborate ((C2H5)4NBF4) in propylene carbonate. The PCNS electrodes displayed high specific capacitance (86 F g-1 for cations and 115 F g-1 for anions). They also showed exceptionally high rate performance with ∼90% capacitance retention at current densities up to 2 A g-1 because their nanosheet structure allowed the rapid diffusion of ions inside the electrode.

  14. Effect of Etching Time on Optical and Thermal Properties of p-Type Porous Silicon Prepared by Electrical Anodisation Method

    Directory of Open Access Journals (Sweden)

    Kasra Behzad

    2012-01-01

    Full Text Available The porous silicon (PSi layers were formed on p-type silicon (Si wafer. The six samples were anodised electrically with 30 mA/cm2 fixed current density for different etching times. The structural, optical, and thermal properties of porous silicon on silicon substrates were investigated by photoluminescence (PL, photoacoustic spectroscopy (PAS, and UV-Vis-NIR spectrophotometer. The thickness and porosity of the layers were measured using the gravimetric method. The band gap of the samples was measured through the photoluminescence (PL peak and absorption spectra, then they were compared. It shows that band gap value increases by raising the porosity. Photoacoustic spectroscopy (PAS was carried out for measuring the thermal diffusivity (TD of the samples.

  15. Preparation of Bioactive Calcium Phosphate Coating on Porous C/C Substrate by a Novel Deposition Technique

    Institute of Scientific and Technical Information of China (English)

    XIONG Xinbo; ZENG Xierong; LI Xiaohua; Xie Shenghui; ZOU Chunli

    2008-01-01

    A novel heat substrate technique,high frequency inductive heat deposition(IHD),was introduced to coat porous carbon materials,C/C and carbon felt to improve their bioactivity.The morphologies,composition and microstructure of the resulting coatings were examined by scanning electron microscopy(SEM),energy dispersive spectra(EDS),X-ray diffractometer(XRD)and Fourier transform infrared spectroscopy (FTIR).The results show that,the calcium phosphate consisted of non-stoichiometric,CO3-containing and plate-like octacalcium phosphate(Ca8-xH2(PO4)6,OCP)could uniformly cover the entire porous surfaces of carbon materials.Good adhesion of the coating to carbon material substrates was observed.

  16. Investigation of the HA film deposited on the porous Ti6Al4V alloy prepared via additive manufacturing

    Science.gov (United States)

    Surmeneva, M.; Chudinova, E.; Syrtanov, M.; Koptioug, A.; Surmenev, R.

    2015-11-01

    This study is focused on the use of radio frequency magnetron sputtering to modify the surface of porous Ti6Al4V alloy fabricated via additive manufacturing technology. The hydroxyapatite (HA) coated porous Ti6Al4V alloy was studied in respect with its chemical and phase composition, surface morphology, water contact angle and hysteresis, and surface free energy. Thin nanocrystalline HA film was deposited while its structure with diamond-shaped cells remained unchanged. Hysteresis and water contact angle measurements revealed an effect of the deposited HA films, namely an increased water contact angle and contact angle hysteresis. The increase of the contact angle of the coating-substrate system compared to the uncoated substrate was attributed to the multiscale structure of the resulted surfaces.

  17. Controlled preparation of porous TiO2-Ag nanostructures through supramolecular assembly for plasmon-enhanced photocatalysis.

    Science.gov (United States)

    Fei, Jinbo; Li, Junbai

    2015-01-14

    By templating Ag(+)-induced supramolecular assembly at different temperatures, porous TiO2-Ag nanotubes and nanospheres are fabricated in a controlled manner due to the effect of Rayleigh instability. Compared with traditional TiO2 nanoparticles, TiO2-Ag nanostructures above show much more extensive visible light absorption and exhibit the noticeably plasmon-enhanced photocatalysis because of the existence of Ag nanoparticles.

  18. Preparation of Polyimide Porous Film with Low Dielectric Constant%低介电常数聚酰亚胺多孔薄膜的制备

    Institute of Scientific and Technical Information of China (English)

    汪英; 周福龙; 王汝柯; 李耀星

    2015-01-01

    以3,3′,4,4′-联苯四甲酸二酐和4,4′-二氨基二苯醚为单体,以三聚氰胺为成孔剂,制得一种聚酰亚胺多孔薄膜,并对薄膜的微观结构、力学性能及介电常数等进行测试。结果表明:制备该聚酰亚胺多孔薄膜的成孔工艺简单可行,三聚氰胺成孔剂可用热水溶解的方法去除。多孔薄膜孔洞数量多,且分布比较均匀。薄膜的介电常数较低、力学性能良好、吸湿率较低。当三聚氰胺添加量分别为25%和40%时,聚酰亚胺多孔薄膜的介电常数分别为1.82和1.36,聚酰亚胺多孔薄膜的拉伸强度分别为86 MPa和74 MPa,断裂伸长率分别为15%和10%。%A polyimide porous film was prepared by using 3,3’,4,4’-biphenyltetracarboxylic dianhydride and 4,4’-diaminodiphenyl ether as monomer, melamine as pore-forming agent, and its microstructure, mechanical properties, and dielectric constant were tested. The results show that the pore-forming process of the polyimide porous film is simple and feasible, and the melamine can be dissolved by hot water. The porous films have a great number of pores and their distribution is uniform. And the porous poly-imide films have low dielectric constant, good mechnical properties, and low water absorption. When the melamine addition content is 25% and 40%, the dielectric constant of the porous polyimide film is 1.82 and 1.36, the tensile strength is 86 MPa and 74 MPa, and the elongation at break is 15% and 10%, respectively.

  19. Ordered and disordered porous materials for nanofiltration application

    NARCIS (Netherlands)

    Chowdhury, Sankhanilay Roy

    2005-01-01

    This Ph.D. dissertation elaborates on the use of porous materials in fluid separation technology. Two different types of porous materials, namely surfactant templated silica and alumina have been used to prepare flat plate geometry porous membranes.

  20. Preparation of hierarchical porous carbon from waste printed circuit boards for high performance electric double-layer capacitors

    Science.gov (United States)

    Du, Xuan; Wang, Li; Zhao, Wei; Wang, Yi; Qi, Tao; Li, Chang Ming

    2016-08-01

    Renewable clean energy and resources recycling have become inevitable choices to solve worldwide energy shortages and environmental pollution problems. It is a great challenge to recycle tons of waste printed circuit boards (PCB) produced every year for clean environment while creating values. In this work, low cost, high quality activated carbons (ACs) were synthesized from non-metallic fractions (NMF) of waste PCB to offer a great potential for applications of electrochemical double-layer capacitors (EDLCs). After recovering metal from waste PCB, hierarchical porous carbons were produced from NMF by carbonization and activation processes. The experimental results exhibit that some pores were formed after carbonization due to the escape of impurity atoms introduced by additives in NMF. Then the pore structure was further tailored by adjusting the activation parameters. Roles of micropores and non-micropores in charge storage were investigated when the hierarchical porous carbons were applied as electrode of EDLCs. The highest specific capacitance of 210 F g-1 (at 50 mA g-1) and excellent rate capability were achieved when the ACs possessing a proper micropores/non-micropores ratio. This work not only provides a promising method to recycle PCB, but also investigates the structure tailoring arts for a rational hierarchical porous structure in energy storage/conversion.

  1. Phase stability and grain growth in an Ag/Bi-2223 composite conductor prepared using fine-grained Bi-2223 as a precursor.

    Energy Technology Data Exchange (ETDEWEB)

    Merchant, N. N.

    1998-09-17

    We have investigated the stability and microstructural transformability of the Bi-2223 phase in a silver-sheathed monofilament composite tape fabricated using fine-grained Bi{sub 1.7}Pb{sub 0.3}Sr{sub 1.9}Ca{sub 2.0}-Cu{sub 3.0}O{sub y} (Bi-2223) as the precursor powder. The fully formed Bi-2223 precursor was prepared using established procedures. The purpose of this study was to explore the prospects for growing textured, large-grain-size Bi-2223 from the fine-grained precursor by process parameter perturbations. These perturbations included thermal ramp up variations, programmed heat treatment temperature and oxygen pressure fluctuations, and parameter manipulations during cool-down. Our results show that the types of heat treatments used in conventional oxide-powder-in-tube (OPIT) processing do not facilitate Bi-2223 grain growth when the precursor powder is preconcerted Bi-2223. We also observed that the Bi-2223 partially. decomposed during conventional thermal ramp-up in 0.075 atm O{sub 2}, but that this decomposition can be inhibited by ramping up in a reduced oxygen pressure. A pathway was found for back-reacting the fine-grained Bi-2223 (to Bi-2212, Bi-2201 and nonsuperconducting secondary phases), then reforming large-grained Bi-2223 in a colony microstructure having some distinct differences from that produced during conventional OPIT processing.

  2. 复合酶酶解制备微孔糯玉米淀粉%Micro-porous Waxy Corn Starch Prepared by Compound Enzyme Enzymolysis

    Institute of Scientific and Technical Information of China (English)

    唐洪波; 王晓宇; 李艳平

    2011-01-01

    以糯玉米淀粉为原料,以α-淀粉酶和葡萄糖淀粉酶复合酶解制备了多孔淀粉,考察了复合酶用量、酶配比、酶解pH、酶解温度和酶解时间对微孔糯玉米淀粉成孔的影响.试验结果表明,上述5个因素对微孔糯玉米淀粉的成孔均有影响.制备微孔糯玉米淀粉的较佳工艺条件为:α-淀粉酶和葡萄糖淀粉酶的比例1∶3,酶解温度55℃,酶解时间12h,pH 5.0,复合酶用量1.5%.比较了容积率法与吸油率法测定微孔糯玉米淀粉成孔的一致性,通过扫描电子显微镜分析微孔糯玉米淀粉的孔结构.%Micro - porous starch was prepared by using waxy com starch as raw material, through the enzymolys-is of compound enzyme composed of a - amylase and glucoamylase in this paper. The effects of factors such as amount of compound enzyme, ratio of α - amylase to glucoamylase, enzymolysis pH, enzymolysis temperature, and enzymolysis time on the pore - forming of waxy corn starch, were discussed. The results showed that the pore - forming of waxy corn starch was influenced by amount of compound enzyme, ratio of a - amylase to glucoamylase, enzymolysis pH value , enzymolysis temperature and enzymolysis time. The better technology conditions of preparing micro - porous waxy com starch were mass ratio of α - amylase to glucoamylase 1: 3, enzymolysis temperature 55 °C, enzymolysis time 12 h, enzymolysis pH 5.0, and amount of compound enzyme 1.5% respectively. The pore - forming consistency of micro - porous waxy corn starch was compared by the volume rate method and oil absorption rate method. The pore structure of micro - porous waxy com starch was observed by SEM.

  3. Influence of Al sub 2 O sub 3 nanoparticles on the thermal stability of ultra-fine grained copper prepared by high pressure torsion

    CERN Document Server

    Cizek, J; Kuzel, R; Islamgaliev, R K

    2002-01-01

    Ultra-fine grained (UFG) Cu (grain size 80 nm) containing 0.5 wt.% Al sub 2 O sub 3 nanoparticles (size 20 nm) was prepared by high pressure torsion (HPT). Positron lifetime spectroscopy was employed to characterize the microstructure of this material, especially with respect to types and concentration of lattice defects. The evolution of microstructure with increasing temperature was studied by positron lifetime spectroscopy and x-ray diffraction measurements. The thermal stability of the Cu + 0.5 wt.% Al sub 2 O sub 3 nanocomposite was compared with that of pure UFG Cu prepared by the same technique. The processes taking place during thermal recovery of the initial nanoscale structure in both studied materials are described. (author)

  4. An aspiration material preparation system: application of a new liquid-based cytology technique for fine-needle aspiration of the breast.

    Science.gov (United States)

    Sakakibara, Eiichi; Kimachi, Setsuo; Hashimoto, Katsunori; Inagaki, Hiroshi; Nagasaka, Tetsuro; Wakusawa, Shinya; Yokoi, Toyoharu

    2011-01-01

    To evaluate the usefulness of our original liquid-based cell preparation system AMAPS (aspiration material preparation system) and to compare it with the AutoSmear system in breast aspiration cytology. A total of 487 specimens of fine-needle aspiration cytology of the breast were retrieved, of which 250 were processed with AMAPS and 237 with the AutoSmear method (before the introduction of AMAPS). A final histological diagnosis was obtained by an excisional biopsy or a surgical resection in 148 cases. Cell recovery rates were significantly improved with AMAPS (96.8 and 99.1% in Papanicolaou and Diff-Quik, respectively) compared with the AutoSmear method (40.9 and 42.3%, respectively; pcytology, the unsatisfactory rate decreased significantly (from 16.0 to 8.8%; pliquid-based cytology systems. Copyright © 2010 S. Karger AG, Basel.

  5. Preparation of ultra-fine powders from polysaccharide-coated solid lipid nanoparticles and nanostructured lipid carriers by innovative nano spray drying technology.

    Science.gov (United States)

    Wang, Taoran; Hu, Qiaobin; Zhou, Mingyong; Xue, Jingyi; Luo, Yangchao

    2016-09-10

    In this study, five polysaccharides were applied as natural polymeric coating materials to prepare solid lipid nanoparticles (SLN) and nanostructure lipid carriers (NLC), and then the obtained lipid colloidal particles were transformed to solid powders by the innovative nano spray drying technology. The feasibility and suitability of this new technology to generate ultra-fine lipid powder particles were evaluated and the formulation was optimized. The spray dried SLN powder exhibited the aggregated and irregular shape and dimension, but small, uniform, well-separated spherical powder particles of was obtained from NLC. The optimal formulation of NLC was prepared by a 20-30% oleic acid content with carrageenan or pectin as coating material. Therefore, nano spray drying technology has a potential application to produce uniform, spherical, and sub-microscale lipid powder particles when the formulation of lipid delivery system is appropriately designed. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Sustainable use of industrial-waste as partial replacement of fine aggregate for preparation of concrete – A review

    Directory of Open Access Journals (Sweden)

    Manoj Kumar Dash

    2016-12-01

    Full Text Available Utilisation of industrial waste materials in concrete compensates the lack of natural resources, solving the disposal problem of waste and to find alternative technique to safeguard the nature. There are a number of industrial wastes used as fully or partial replacement of coarse aggregate or fine aggregate. This review carries out a thorough assessment about industrial waste substances, which can be adequately utilised in concrete as fine aggregate substitution. This paper reviewed some of these industrial wastes like waste foundry sand, steel slag, copper slag, imperial smelting furnace slag (ISF slag, blast furnace slag, coal bottom ash, ferrochrome slag, palm oil clinker etc. Out of these materials, maximum number of experiments have been conducted using waste foundry sand and copper slag as fine aggregate replacement, but still more examinations are required for other waste materials as replacement of sand in concrete. Different physical and mechanical properties of industrial waste as well as of industrial waste concrete, in which natural sand is substituted have been reviewed and comparisons are made between them. Deflection and leaching study review are carried out additionally and compared. It can be observed that the concrete where sand is replaced by copper slag, imperial smelting furnace slag, class F fly ash exhibits improved strength and durability properties, but it’s slump increases as the rate of replacement increases in the case of copper slag and the slump decreases in the case of class F fly ash. There is a less research work reported on ferrochrome slag and palm oil clinker used as sand substitution, so it is felt that further detailed investigations are required.

  7. Preparation of Porous Crystalline Spherical Titania under Atmospheric Liquid Phase Conditions%结晶二氧化钛多孔球的常压液相制备

    Institute of Scientific and Technical Information of China (English)

    申乾宏; 黎胜; 宗建娟; 杨辉

    2009-01-01

    Porous crystalline spherical titania was facilely prepared by treating the organic titanium precursor spheres with boiling water. The spherical titania was characterized by X-ray diffraction, scanning electron mi-croscopy and transmission electron microscopy. The probable mechanism for formation of anatase nanocrystal and the morphology change of precursor spheres was also discussed. The results demonstrate that extending the treating time in boiling water is helpful for the formation of porous structure as well as the crystallization of nanoparticles. With increasing in treating time, the surface of the procursor spheres become rougher and rougher, and the crys-tallinity of anatase titania improves gradually. The forming mechanism of porous structure and anatase nanoerystal is attributed to the complete in-situ hydrolysis and condensation of the organic titanium precursor spheres in boiling water.%利用沸水处理有机钛前驱体球较为便捷地制备出结晶二氧化钛多孔球,采用XRD、SEM和TEM对二氧化钛球进行表征,并探讨了二氧化钛球锐钛矿纳米晶形成以及形貌变化的机理.结果表明:延长沸水处理时间有利于多孔结构的形成和纳米粒子的晶化,随处理时间的增加,前驱体球表面变得越来越粗糙,二氧化钛结晶度也逐渐增强.其形成机理主要归因于沸水处理过程中有机钛前驱体球原位发生的完全水解和聚合.

  8. Preparation of porous SnO{sub 2} helical nanotubes and SnO{sub 2} sheets

    Energy Technology Data Exchange (ETDEWEB)

    Fei, Ling; Xu, Yun [Department of Chemical Engineering, New Mexico State University, Las Cruces, NM 88003 (United States); Chen, Zheng [Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, CA 90095 (United States); Yuan, Bin; Wu, Xiaofei; Hill, Joshua; Lin, Qianglu; Deng, Shuguang; Andersen, Paul [Department of Chemical Engineering, New Mexico State University, Las Cruces, NM 88003 (United States); Lu, Yunfeng [Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, CA 90095 (United States); Luo, Hongmei, E-mail: hluo@nmsu.edu [Department of Chemical Engineering, New Mexico State University, Las Cruces, NM 88003 (United States)

    2013-06-15

    We report a surfactant-free chemical solution route for synthesizing one-dimensional porous SnO{sub 2} helical nanotubes templated by helical carbon nanotubes and two-dimensional SnO{sub 2} sheets templated by graphite sheets. Transmission electron microscopy, X-ray diffraction, cyclic voltammetry, and galvanostatic discharge–charge analysis are used to characterize the SnO{sub 2} samples. The unique nanostructure and morphology make them promising anode materials for lithium-ion batteries. Both the SnO{sub 2} with the tubular structure and the sheet structure shows small initial irreversible capacity loss of 3.2% and 2.2%, respectively. The SnO{sub 2} helical nanotubes show a specific discharge capacity of above 800 mAh g{sup −1} after 10 charge and discharge cycles, exceeding the theoretical capacity of 781 mAh g{sup −1} for SnO{sub 2}. The nanotubes remain a specific discharge capacity of 439 mAh g{sup −1} after 30 cycles, which is better than that of SnO{sub 2} sheets (323 mAh g{sup −1}). - Highlights: • Synthesized porous SnO{sub 2} helical nanotubes with diameters of 100–120 nm. • Synthesized porous SnO{sub 2} sheets template by graphite sheets. • The tubular and sheet SnO{sub 2} have small initial irreversible capacity loss of 3.2 and 2.2%. • The tubular structure shows better discharge capacity than the sheet structure.

  9. Preparation of Porous Core-Shell Poly L-Lactic Acid/Polyethylene Glycol Superfine Fibres Containing Drug.

    Science.gov (United States)

    Yang, Wenjing; He, Nongyue; Fu, Juan; Li, Zhiyang; Ji, Xuyuan

    2015-12-01

    In this paper, poly L-lactic acid (PLLA) blended with polyethylene glycol (PEG) was dissolved in methylene dichloride solution as the shell solution, and rapamycin (RAPA), was encapsulated inside the core of PLLA micro/nano fibres as a model drug. The effects of the blending ratio of PLLA to PEG, the concentration of the electrospinning solution, the voltage, the flow rate, and the encapsulation efficiency were studied. Uniform and porous RAPA-Loading PLLA fibres were obtained when the ratio of PLLA to PEG was 7/3, the concentration of PLLA was 3%, the applied voltage was 7.5 kV, and the pump speed was V(core) = 0.1 mL/h, V(shell) = 1 mL/h, repectively. The average diameter of PLLA fibres increased with the gradual increase in PLLA concentration. FTIR results showed that RAPA was successfully encapsulated into the core-co-shell PLLA fibres. Meanwhile, the RAPA-loading of coaxial electrospun PLLA fibres was significantly higher than that of the blending electrospun fibres. It was also found that the porous core-shell PLLA/PEG blending superfine fibres could regulate the appearance of pore on the surface of superfine fibres by adjusting the electrospinning parameters. The porous PLLA/PEG blending fibres can be used as drug carriers and, to improve the single way of drug release depending on the degradation of shell material to meet different need. It will be a remarkable breakthrough in the area for sustained and controlled release drug delivery system.

  10. Catalytic membranes prepared using layer-by-layer adsorption of polyelectrolyte/metal nanoparticle films in porous supports.

    Science.gov (United States)

    Dotzauer, David M; Dai, Jinhua; Sun, Lei; Bruening, Merlin L

    2006-10-01

    Layer-by-layer adsorption of polyelectrolytes and gold nanoparticles within porous supports provides a convenient method for forming catalytic membranes. The polyelectrolyte film effectively immobilizes the gold nanoparticles without inhibiting access to catalytic sites, as shown by the similar rate constants for nanoparticle-catalyzed 4-nitrophenol reduction in solution and in membranes. Modified alumina membranes reduce >99% of 0.4 mM 4-nitrophenol at linear flow rates of 0.98 cm/s, and the modification process is also applicable to track-etched polycarbonate supports.

  11. Preparation of Porous Anodic Alumina Membrance on Glass Substrate%玻璃基底上多孔氧化铝模板的制备

    Institute of Scientific and Technical Information of China (English)

    李宏

    2014-01-01

    Al thin films were deposited by magnetron sputtering on the glass slide .And then , the porous anodic alumina membrance was fabricated by anodic oxidation in phosphate solution .Scanning electron micro-scope (SEM) showed that the highly ordered porous anodic alumina membrance without barrier layer was fabrica -ted under the condition of 195 V of voltage , 60 s of time .This method can be employed to prepare other kinds of nanostructures on the rigid substrates .%利用磁控溅射在玻璃基底上直接溅射一层铝薄膜,然后利用阳极氧化制备了多孔氧化铝模板,扫描电子显微镜图片显示在195V、60s的条件下获得的多孔氧化铝模板孔道排列规则,且双向贯通。这种方法为在玻璃等硬质基底上制备规则的纳米结构提供了一种有效途径。

  12. Optimal Conditions for Preparing Ultra-Fine CeO2 Powders in A Submerged Circulative Impinging Stream Reactor

    Institute of Scientific and Technical Information of China (English)

    Chi Ru'an; Xu Zhigao; Wu Yuanxin; Wang Cunwen

    2007-01-01

    Cerium carbonate powders were produced in a submerged circulation impinging stream reactor (SCISR) from Ce(NO3)3·6H2O. NH4HCO3 was used as a precipitant in the reaction. Cerium carbonate powders were roasted to produce ultra-fine cerium dioxide (CeO2) powders. The optimal conditions of such production process were obtained by orthogonal and one-factor experiments. The results showed that ultra-fine and narrowly distributed cerium carbonate powders were produced under the optimal flowing conditions. The concentrations of Ce(NO3)3 and NH4HCO3 solutions were 0.25 and 0.3 mol·L-1, respectively. The concentration of PEG4000 added in these two solutions was 4 g·L-1. The stirring ratio, reaction temperature, feeding time, solution pH, reaction time and digestion time were 900 r·min-1, 80 ℃, 20 min, 5~6, 5 min and 1 h, respectively. The final product, CeO2 powders, was obtained by roasting the produced cerium carbonate in air for 3 h at 500 ℃. The finally produced CeO2 powders were torispherical particles with a narrow size distribution of 0.8~2.5 μm. The crystal structure of CeO2 powders belonged to cubic crystal system and its space point group was O5H-FM3M. Under optimal conditions, powders produced by SCISR were finer and more narrowly distributed than that by Stirred Tank Reactor (STR).

  13. Preparation of Porous Stainless Steel Hollow-Fibers through Multi-Modal Particle Size Sintering towards Pore Engineering.

    Science.gov (United States)

    Allioux, Francois-Marie; David, Oana; Etxeberria Benavides, Miren; Kong, Lingxue; Pacheco Tanaka, David Alfredo; Dumée, Ludovic F

    2017-08-04

    The sintering of metal powders is an efficient and versatile technique to fabricate porous metal elements such as filters, diffusers, and membranes. Neck formation between particles is, however, critical to tune the porosity and optimize mass transfer in order to minimize the densification process. In this work, macro-porous stainless steel (SS) hollow-fibers (HFs) were fabricated by the extrusion and sintering of a dope comprised, for the first time, of a bimodal mixture of SS powders. The SS particles of different sizes and shapes were mixed to increase the neck formation between the particles and control the densification process of the structure during sintering. The sintered HFs from particles of two different sizes were shown to be more mechanically stable at lower sintering temperature due to the increased neck area of the small particles sintered to the large ones. In addition, the sintered HFs made from particles of 10 and 44 μm showed a smaller average pore size (<1 μm) as compared to the micron-size pores of sintered HFs made from particles of 10 μm only and those of 10 and 20 μm. The novel HFs could be used in a range of applications, from filtration modules to electrochemical membrane reactors.

  14. Fine yellow α-SiAlON:Eu phosphors for white LEDs prepared by the gas-reduction–nitridation method

    Directory of Open Access Journals (Sweden)

    Hui-Li Li et al

    2007-01-01

    Full Text Available Yellow-emitting α-SiAlON:Eu2+ phosphors were synthesized by the gas reduction and nitridation of a homogeneous oxide precursor in a CaO–Al2O3–SiO2–Eu2O3 system at 1400–1450 °C using an NH3–CH4 mixture gas as a reduction–nitridation agent. The precursor was prepared by a sol–gel process using a low-cost nitrate, tetraethyl orthosilicate and citric acid as the starting materials. The effects of reaction parameters such as heating rate, temperature, holding time and CH4 content on the composition, microstructure and photoluminescence of the prepared powders were investigated. Nearly single-phase α-SiAlON was successfully synthesized by the one-step gas reduction and nitridation without the need for post-annealing at a higher temperature. The prepared powders consisted of relatively well-dispersed and uniform crystals with a hexagonal shape. The photoluminescence spectra of Eu-doped Ca-α-SiAlON phosphors excited by near-ultraviolet or blue light showed a broad, yellow emission band at 500–700 nm, which agrees well with that obtained from phosphors prepared by the conventional solid-state reaction.

  15. Preparation of porous styrenics-based monolithic layers for thin layer chromatography coupled with matrix-assisted laser-desorption/ionization time-of-flight mass spectrometric detection.

    Science.gov (United States)

    Lv, Yongqin; Lin, Zhixing; Tan, Tianwei; Svec, Frantisek

    2013-11-01

    Monolithic 50 μm thin poly(4-methylstyrene-co-chloromethylstyrene-co-divinylbenzene) layers attached to 6.0 cm × 3.3 cm glass plates have been prepared, using a thermally initiated polymerization process. These layers had a well-defined porous structure with a globular morphology demonstrated with SEM images and exhibited superhydrophobic properties characterized with a water contact angle of 157°. They were then used for thin-layer chromatography of peptides and proteins fluorescently labeled with fluorescamine. The spots of individual separated compounds were visualized using UV light, and their identities were confirmed with a matrix-assisted laser desorption/ionization time of flight mass spectrometry. The presence of chloromethylstyrene units in the polymer enabled hypercrosslinking via a Friedel-Crafts alkylation reaction, and led to monoliths with much larger surface areas, which were suitable for separations of small dye molecules.

  16. Catalytic Graphitization for Preparation of Porous Carbon Material Derived from Bamboo Precursor and Performance as Electrode of Electrical Double-Layer Capacitor

    Science.gov (United States)

    Tsubota, Toshiki; Maguchi, Yuta; Kamimura, Sunao; Ohno, Teruhisa; Yasuoka, Takehiro; Nishida, Haruo

    2015-12-01

    The combination of addition of Fe (as a catalyst for graphitization) and CO2 activation (a kind of gaseous activation) was applied to prepare a porous carbon material from bamboo powder (a waste product of superheated steam treatment). Regardless of the heat treatment temperature, many macropores were successfully formed after the heating process by removal of Fe compounds. A turbostratic carbon structure was generated in the Fe-added sample heated at 850°C. It was confirmed that the added Fe acted as a template for pore formation. Moreover, it was confirmed that the added Fe acted as a catalyst for graphitization. The resulting electrochemical performance as the electrode of an electrical double-layer capacitor, as demonstrated by cyclic voltammetry, electrochemical impedance spectroscopy, and charge-discharge testing, could be explained based on the graphitization and activation effects. Addition of Fe could affect the electrical properties of carbon material derived from bamboo.

  17. Preparation of Scratch-Resistant Nano-Porous Silica Films Derived by Sol-Gel Process and Their Anti-reflective Properties

    Institute of Scientific and Technical Information of China (English)

    Guangming WU; Jun SHEN; Tianhe YANG; Bin ZHOU; Jue WANG

    2003-01-01

    Structural strengthening of the nano porous silica films has been reported. The films were prepared with a base/acid two-step catalyzed TEOS-based sol-gel processing and dip-coating, and then baked in the mixed gas of ammonia and water vapor. The silica films were characterized with TEM, AFM, FTIR, spectrophotometer, ellipsometer, and abrasion test, respectively. The experimental results have shown that the films have a nanostructure with a low refractive index and can form an excellent scratch-resistant broadband anti-reflectance. The two-step catalysis noticeably strengthens the films, and the mixed gas treatment further improves mechanical strength of the silica network. Finally the strengthening mechanism has been discussed.

  18. The preparation of porous superfine calcium carbonate microspheres%多孔超细碳酸钙微球的制备

    Institute of Scientific and Technical Information of China (English)

    杨辉; 李欢

    2013-01-01

    采用乳状液膜与共沉淀结合法制备多孔超细碳酸钙微球,考察了不同反应条件对碳酸钙微球形貌的影响.通过X射线衍射、扫描电子显微镜及激光粒度仪对所得的碳酸钙微球的晶体组成、形貌以及粒度进行了表征.结果表明,超细碳酸钙微球生成的最佳工艺条件为:CaCl2溶液浓度0.1 mol/L、吐温-80加量4 mL、超声乳化5 min、搅拌反应3 h ,此工艺条件下获得多孔碳酸钙微球粒径在2~10μm ,球形圆整,且组成为球霰石与方解石的共混体.%The porous superfine calcium carbonate microspheres was prepared by using a e-mulsion liquid membrane method combining with a precipitation method in this paper . Effects of different reaction conditions on the calcium carbonate microspheres morphology were investigated ,and finally the crystal composition ,morphology and particle size of the obtained calcium carbonate were characterized through X-ray diffraction (XRD) ,scanning e-lectron microscope(SEM ) and laser particle size instrument .The results showed that the op-timal conditions for porous superfine calcium carbonate microspheres are as follow s :the so-lution concentration of CaCl2 was 0 .15 mol/L ,the amount of Tween-80 used in preparation was 4 mL ,the time of ultrasonic emulsification was 5 min ,the reaction time with stirring was 3 h .Under these conditions ,the particle size of porous superfine calcium carbonate ranged from 2 to 10 μm ,round ,and composed of the vaterite and calcite .

  19. Normal and abnormal grain growth in fine-grained Nd-Fe-B sintered magnets prepared from He jet milled powders

    Science.gov (United States)

    Bittner, F.; Woodcock, T. G.; Schultz, L.; Schwöbel, C.; Gutfleisch, O.; Zickler, G. A.; Fidler, J.; Üstüner, K.; Katter, M.

    2017-03-01

    Fine-grained, heavy rare earth free Nd-Fe-B sintered magnets were prepared from He jet milled powders with an average particle size of 1.5 μm by low temperature sintering at 920 °C or 980 °C. A coercivity of >1600 kA/m was achieved for an average grain size of 1.68 μm. Transmission electron microscopy showed that the distribution and composition of intergranular and grain boundary junction phases was similar to that in conventionally processed magnets. Microstructural analysis on different length scales revealed the occurrence of abnormal grain growth, which is unexpected for sintering temperatures below 1000 °C. A larger area fraction of abnormal grains was observed in the sample sintered at 920 °C compared to that sintered at 980 °C. Microtexture investigation showed a better crystallographic alignment of the abnormal grains compared to the fine-grained matrix, which is explained by a size dependent alignment of the powder particles during magnetic field alignment prior to sintering. Slightly larger particles in the initial powder show a better alignment and will act as nucleation sites for abnormal grain growth. Magneto-optical Kerr investigations confirmed the lower switching field of the abnormal grains compared to the fine-grained matrix. The demagnetisation curve of the sample sintered at 920 °C showed reduced rectangularity and this was attributed to a cooperative effect of the larger fraction of abnormal grains with low switching field and, as a minor effect, a reduced degree of crystallographic texture in this sample compared to the material sintered at 980 °C, which did not show the reduced rectangularity of the demagnetisation curve.

  20. Fine structures and states of water in poly(vinyl alcohol) hydrogels prepared by repeated freezing and thawing

    OpenAIRE

    1997-01-01

    Investigations have been made into the relationship between structure and states of water in unfrozen poly (vinyl alcohol) (PVA) hydrogels prepared by repeated freezing and thawing of aqueous solution with various PVA concentrations. The states of water were investigated by using a pulsed nuclear magnetic resonance spectroscopy. Every unfrozen PVA hydrogel gave only one spin-lattice relaxation time (T-1) value. T-1 of all unfrozen hydrogels were smaller than that of free water and decreased w...

  1. PREPARATION OF MONODISPERSE POLYSTYRENE MICROSPHERES BY SHELL POROUS GLASS-SUSPENSION POLYMERIZATION%用多孔玻璃膜管-悬浮聚合法制备单分散性聚苯乙烯微球

    Institute of Scientific and Technical Information of China (English)

    范星河; 谢晓峰

    2001-01-01

    Monodisperse polystyrene microspheres are prepared by shell porous glass(SPG)-suspension polymerization. The influences of SPG on size and size dispersity of the microspheres are investigated. The properties of the microspheres are studied by GPC, TEM and SEM. The results indicate that the polystyrene microspheres possess definite monodispersibity and their particle size is in the range of 5~12μm.

  2. 多孔钛片载薄膜型光催化剂的制备与性质%PREPARATION AND PROPERTIES OF THIN PHOTOCATALYSTS FILMS ON POROUS TITANIUM PLATE

    Institute of Scientific and Technical Information of China (English)

    张渊明; 成英之

    2001-01-01

    The TiO2 films were prepared by sol-gel method on porous titaniumplate,and the products had been characterized by XRD,SEM,UV-Vis.spectra.The results showed that TiO2 was of catalytic actixity and the films absorbed UV and visible light intensively.

  3. Towards a generic method for inorganic porous hollow fibers preparation with shrinkage-controlled small radial dimensions, applied to Al2O3, Ni, SiC, stainless steel, and YSZ

    NARCIS (Netherlands)

    Luiten-Olieman, M.W.J.; Raaijmakers, M.J.T.; Winnubst, A.J.A.; Bor, T.C.; Wessling, M.; Nijmeijer, A.; Benes, N.E.

    2012-01-01

    A versatile method is presented for the preparation of porous inorganic hollow fibers with small tunable radial dimensions, down to ∼250 μm outer diameter. The approach allows fabrication of thin hollow fibers of various materials, as is demonstrated for alumina, nickel, silicon carbide, stainless s

  4. Towards a generic method for inorganic porous hollow fibers preparation with shrinkage-controlled small radial dimensions, applied to Al2O3, Ni, SiC, stainless steel, and YSZ

    NARCIS (Netherlands)

    Luiten-Olieman, Maria W.J.; Raaijmakers, Michiel; Winnubst, Aloysius J.A.; Bor, Teunis Cornelis; Wessling, Matthias; Nijmeijer, Arian; Benes, Nieck Edwin

    2012-01-01

    A versatile method is presented for the preparation of porous inorganic hollow fibers with small tunable radial dimensions, down to ∼250 μm outer diameter. The approach allows fabrication of thin hollow fibers of various materials, as is demonstrated for alumina, nickel, silicon carbide, stainless

  5. Investigation of Physicochemical Drug Properties to Prepare Fine Globular Granules Composed of Only Drug Substance in Fluidized Bed Rotor Granulation.

    Science.gov (United States)

    Mise, Ryohei; Iwao, Yasunori; Kimura, Shin-Ichiro; Osugi, Yukiko; Noguchi, Shuji; Itai, Shigeru

    2015-01-01

    The effect of some drug properties (wettability and particle size distribution) on granule properties (mean particle size, particle size distribution, sphericity, and granule strength) were investigated in a high (>97%) drug-loading formulation using fluidized bed rotor granulation. Three drugs: acetaminophen (APAP); ibuprofen (IBU); and ethenzamide (ETZ) were used as model drugs based on their differences in wettability and particle size distribution. Granules with mean particle sizes of 100-200 µm and a narrow particle size distribution (PSD) could be prepared regardless of the drug used. IBU and ETZ granules showed a higher sphericity than APAP granules, while APAP and ETZ granules exhibited higher granule strength than IBU. The relationship between drug and granule properties suggested that the wettability and the PSD of the drugs were critical parameters affecting sphericity and granule strength, respectively. Furthermore, the dissolution profiles of granules prepared with poorly water-soluble drugs (IBU and ETZ) showed a rapid release (80% release in 20 min) because of the improved wettability with granulation. The present study demonstrated for the first time that fluidized bed rotor granulation can prepare high drug-loaded (>97%) globular granules with a mean particle size of less than 200 µm and the relationship between physicochemical drug properties and the properties of the granules obtained could be readily determined, indicating the potential for further application of this methodology to various drugs.

  6. Manufacturing of Porous Polycaprolactone Prepared with Different Particle Sizes and Infrared Laser Sintering Conditions: Microstructure and Mechanical Properties

    Directory of Open Access Journals (Sweden)

    G. V. Salmoria

    2014-08-01

    Full Text Available The techniques of Rapid Prototyping, also known as Additive Manufacturing, have prompted research into methods of manufacturing polymeric materials with controlled porosity. This paper presents the characterization of the structure and mechanical properties of porous polycaprolactone (PCL fabricated by Selective Laser Sintering (SLS using two different particle sizes and laser processing conditions. The results of this study indicated that it is possible to control the microstructure, that is, pore size and degree of porosity, of the polycaprolactone matrix using the SLS technique, by varying the particle size and laser energy density, obtaining materials suitable for different applications, scaffolds and drug delivery and fluid mechanical devices. The specimens manufactured with smaller particles and higher laser energy density showed a higher degree of sintering, flexural modulus, and fatigue resistance when compared with the other specimens.

  7. Preparation of Well Dispersed and Ultra-Fine Ce(Zr)O2 Mixed Oxide by Mechanochemical Processing

    Institute of Scientific and Technical Information of China (English)

    程昌明; 李永绣; 周雪珍; 陈伟凡

    2004-01-01

    Ultra-fine CeO2-ZrO2 mixed oxide was successfully synthesized by wet-solid phase mechanochemical processing, Ce2(CO3)3·8H2O, ZrOCl2·xH2O and ammonia were used as reactants. It is found that the crystalline Ce2(CO3)3·8H2O and ZrOCl2·xH2O are changed to amorphous cerium and zirconium hydroxide precursor after milling with ammonia, and Ce0.15Zr0.85O2 mixed oxide with pure tetragonal phase structure and medium particle size(D50)less than 1μm is formed by calcining precursor over 673 K. The XRD patterns indicate that the crystal unite size increases with rising calcining temperature due to crystal growth. However, the particle size and BET surface area of the Ce(Zr)O2 mixed oxide decreases with rising calcining temperature, which may be attributed to the contract of particles and the vanish of holes inside grains.

  8. Preparation of active proteins, vaccines and pharmaceuticals as fine powders using supercritical or near-critical fluids.

    Science.gov (United States)

    Cape, Stephen P; Villa, Joseph A; Huang, Edward T S; Yang, Tzung-Horng; Carpenter, John F; Sievers, Robert E

    2008-09-01

    Supercritical or near-critical fluid processes for generating microparticles have enjoyed considerable attention in the past decade or so, with good success for substances soluble in supercritical fluids or organic solvents. In this review, we survey their application to the production of protein particles. A recently developed process known as CO2-assisted nebulization with a Bubble Dryer (CAN-BD) has been demonstrated to have broad applicability to small-molecule as well as macromolecule substances (including therapeutic proteins). The principles of CAN-BD are discussed as well as the stabilization, micronization and drying of a wide variety of materials. More detailed case studies are presented for three proteins, two of which are of therapeutic interest: anti-CD4 antibody (rheumatoid arthritis), alpha1-antitrypsin (cystic fibrosis and emphysema), and trypsinogen (a model enzyme). Dry powders were formed in which stability and activity are maintained and which are fine enough to be inhaled and reach the deep lung. Enhancement of apparent activity after CAN-BD processing was also observed in some formulation and processing conditions.

  9. Preparation of fine-grained tungsten heavy alloys by spark plasma sintered W–7Ni–3Fe composite powders with different ball milling time

    Energy Technology Data Exchange (ETDEWEB)

    Xiang, D.P., E-mail: dpxiang@hainu.edu.cn [Key Laboratory of Advanced Materials of Tropical Island Resources, Ministry of Education, Hainan University, Haikou 570228 (China); School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640 (China); Ding, L. [Key Laboratory of Advanced Materials of Tropical Island Resources, Ministry of Education, Hainan University, Haikou 570228 (China); Li, Y.Y.; Chen, G.B. [School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640 (China); Zhao, Y.W. [Key Laboratory of Advanced Materials of Tropical Island Resources, Ministry of Education, Hainan University, Haikou 570228 (China)

    2013-06-15

    Highlights: ► We fabricate fine-grained W–7Ni–3Fe alloys using HEBM assisted SPS method. ► The γ-(Ni, Fe, W) phase is not observed in HEBM raw powders. ► The density of the WHAs gradually decreased with increasing HEBM time. ► The hardness and bending strength of the WHAs show different trends of variation. ► The intergranular fracture was the main bending fracture mode of the WHAs. -- Abstract: The fine-grained tungsten heavy alloys (WHAs) with grain size of about 1–3 μm were successfully prepared by spark plasma sintered W–7Ni–3Fe composite powders with different high-energy ball milling (HEBM) time. This study analyzes the effects of HEBM time not only on the composite powders but on the microstructure and mechanical properties of WHAs. The scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to investigate the microstructure and phase evolution rules of powders and alloys, respectively. The γ-(Ni, Fe, W) is not observed in XRD patterns of the ball milled powders. With prolonging HEBM time, the W phase diffraction peak becomes increasingly wider, and its intensity continues to decline. However, the completely amorphous structures are not formed even after HEBM 40 h. The relative density of the WHAs prepared by HEBM assisted SPS technique decreases gradually with increasing the ball milling time. For the WHAs sintered in 1150 °C for 8 min, the W grains grow finer and the content of the γ-(Ni, Fe, W) binding phase greatly increases with prolonging the HEBM time. Meanwhile, over 5 h of HEBM time, the bending strength continuously decreases and the hardness slightly increases. The intergranular fracture of the W grains is the main bending fracture mode in all the WHAs. The microporous of different sizes are distributed on the bending fracture and progressively increased with prolonging the ball milling time.

  10. Comparison of Thin-Prep and cell block preparation for the evaluation of Thyroid epithelial lesions on fine needle aspiration biopsy

    Directory of Open Access Journals (Sweden)

    Hammoud Jamal

    2008-01-01

    Full Text Available Abstract Background The objective of this study was to compare the utility of Thin-Prep (TP cytologic preparation with that of Cell Block (CB preparation in the diagnosis of thyroid lesions, mainly follicular epithelial lesions, by fine needle aspiration biopsy (FNAB. Feasibility of using the TP slides for immunocytochemical stains is also discussed. Methods A total of 126 consecutive cases of thyroid FNAB with TP slides and 128 consecutive cases of thyroid FNAB with CB slides were reviewed blindly by two cytopathologists. The presence of colloid, follicular cells, macrophages and lymphocytes/plasma cells were recorded and scored 0–4 on each case based on TP or CB slide review. The cytologic diagnoses were grouped as follows: cyst, colloid nodule, colloid nodule with cystic change, chronic thyroiditis, atypical/neoplastic and non-diagnostic. Results The TP slides had higher diagnostic rate than CB slides. The diagnostic yield was 68% of the TP slides whereas only 24% of the CB slides were diagnostic. Also, only 4 atypical/neoplastic lesions were diagnosed on the TP slides and the corresponding direct smears, while 5 cases of atypical/neoplastic lesions were diagnosed on the smears but could not be diagnosed on the corresponding CB slides. Additionally, the TP slides revealed cytologic features that were not observed on the direct traditional smears of the same case. Conclusion In thyroid FNAB cases, TP slide preparation is superior to CB slide preparation and is more likely to have greater cellularity for diagnosis and detect atypical/neoplastic thyroid lesions, particularly those of follicular cell origin. Furthermore, TP slides appear to detect helpful diagnostic cytologic features and should be considered complementary to, rather than replacing, direct smears.

  11. Using of acid hydrolysis for preparation of porous starch and feature analysis%酸法制备多孔淀粉及其特性研究

    Institute of Scientific and Technical Information of China (English)

    李梅; 刘可志; 徐雅雯; 孙平

    2012-01-01

    Porous starch was made of corn starch by using of different concentrations of hydrochloric acid or compound enzyme under certain conditions.The morphology and some properties of the prepared porous starch were determined.Water absorption and oil absorption of the two products were compared.The results showed that the porous starch which made in the conditions of solid to liquid ratio 1:4,the concentration of hydrochloric acid 8% ,temperature 45~(3 and time 20h was similar to that made by enzymatic hydrolysis on water absorption and oil absorption,and the property was greatly improved on the basis of the native starch.The SEM results showed that the surface of porous starch made by enzymatic hydrolysis was covered with holes and pits. But the starch granules made by acid hydrolysis were random, and the effect was worse than enzymatic hydrolysis. Compared with native starch,gelatinization start temperature of porous starch was slightly increased but peak viscosity was decreased in a great degree.With high price advantage than enzymatic hydrolysis,acid hydrolysis was simple and inexpensive,and had industrial production value.%以玉米淀粉为原料,分别用不同浓度的盐酸溶液和复合酶在一定条件下制备多孔淀粉。对制得的多孔淀粉进行形态结构和部分性质的测定,并对两种方式处理所得产品的吸水性和吸油性进行对比。结果显示,料液比1:4、8%浓度的盐酸溶液、45℃下水浴反应20h制备的多孔淀粉在吸水和吸油性能上与酶法制备的多孔淀粉较为相似,同时相对于原淀粉性能有很大的提高。扫描电子显微镜(SEM)显示,酶法制备的多孔淀粉表面布有类似蜂窝状的孔洞或凹坑,而酸法制得的多孔淀粉颗粒具有随机性,效果不如酶法处理。与原淀粉相比,酸法制备的多孔淀粉糊化开始温度略微升高,而峰值黏度有很大降低。酸法制备多孔淀粉的方法简单廉价,相对酶

  12. Preparation of fine, uniform nitrogen- and sulfur-modified TiO2 nanoparticles from titania nanotubes

    Directory of Open Access Journals (Sweden)

    Mathieu Grandcolas and Jinhua Ye

    2010-01-01

    Full Text Available TiO2 nanoparticles modified with nitrogen and sulfur were prepared from titania nanotubes by a facile wet chemistry method. The samples synthesized with different thiourea/TiO2 ratios showed a uniform nanoparticle size distribution centred at approximately 10 nm with a developed specific surface area of 246 m2 g-1. These modified nanosized photocatalysts exhibited higher photocatalytic activity for the degradation of gaseous isopropanol than unmodified titania nanotubes under visible illumination. This could be attributed to the synergistic effects of a large specific surface area, strong absorption in the visible region, a redshift in the adsorption edge, and surface adsorption modification induced by nitrogen and sulfur compounds.

  13. Bactericidal activity and silver release of porous ceramic candle filter prepared by sintering silica with silver nanoparticles/zeolite for water disinfection

    Science.gov (United States)

    Trinh Nguyen, Thuy Ai; Phu Dang, Van; Duy Nguyen, Ngoc; Le, Anh Quoc; Thanh Nguyen, Duc; Hien Nguyen, Quoc

    2014-09-01

    Porous ceramic candle filters (PCCF) were prepared by sintering silica from rice husk with silver nanoparticles (AgNPs)/zeolite A at about 1050 °C to create bactericidal PCCF/AgNPs for water disinfection. The silver content in PCCF/AgNPs was of 300-350 mg kg-1 determined by inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and the average pore size of PCCF/AgNPs was of 50-70 Å measured by Brunauer-Emmett-Teller (BET) method. The bactericidal activity and silver release of PCCF/AgNPs have been investigated by flow test with water flow rate of 5 L h-1 and initial inoculation of E. coli in inlet water of 106 CFU/100 mL. The volume of filtrated water was collected up to 500 L. Results showed that the contamination of E. coli in filtrated water was water was low, far under the WHO guideline of 100 μg L-1 at maximum for drinking water. Based on the content of silver in PCCF/AgNPs and in filtrated water, it was estimated that one PCCF/AgNPs could be used to filtrate of ˜100 m3 water. Thus, as-prepared PCCF/AgNPs releases low content of silver into water and shows effectively bactericidal activity that is promising to apply as point-of-use water treatment technology for drinking water disinfection.

  14. Facile preparation of hierarchically porous diatomite/MFI-type zeolite composites and their performance of benzene adsorption: the effects of NaOH etching pretreatment.

    Science.gov (United States)

    Yu, Wenbin; Yuan, Peng; Liu, Dong; Deng, Liangliang; Yuan, Weiwei; Tao, Bo; Cheng, Hefa; Chen, Fanrong

    2015-03-21

    Hierarchically porous diatomite/MFI-type zeolite (Dt/Z) composites with excellent benzene adsorption performance were prepared. The hierarchical porosity was generated from the microporous zeolite coated at the surface of diatom frustules and from the macroporous diatomite support. A facile NaOH etching method was employed for the first time to treat the frustule support, followed by hydrothermal growth of MFI-type zeolite at the surface of frustules previously seeded with nanocrystalline silicalite-1 (Sil-1). NaOH etching enlarged the pores on diatom frustules and further increased the coated zeolite contents (W(z)). The central macropore size of the diatom frustules increased from approximately 200-500 nm to 400-1000 nm after NaOH etching. The W(z) could reach 61.2%, while the macroporosity of the composites was largely preserved due to more voids for zeolite coating being formed by NaOH etching. The Dt/Z composites exhibited higher benzene adsorption capacity per unit mass of zeolite and less mass transfer resistance than Sil-1, evaluated via a method of breakthrough curves. These results demonstrate that etching of a diatomite support is a facile but crucial process for the preparation of Dt/Z composites, enabling the resulting composites to become promising candidates for uses in volatile organic compounds emission control. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. The preparation of composite microsphere with hollow core/porous shell structure by self-assembling of latex particles at emulsion droplet interface.

    Science.gov (United States)

    He, Xiao Dong; Ge, Xue Wu; Wang, Mo Zhen; Zhang, Zhi Cheng

    2006-07-15

    A submicrometer-scaled polystyrene/melamine-formaldehyde hollow microsphere composite was prepared by self-assembling of sulfonated polystyrene (SPS) latex particles at the interface of emulsion droplets and then being fixed in place using a hard melamine-formaldehyde (MF) composite layer. For control-released purposes, the influential factors that control the size and uniformity of the packed-droplets and the permeability of the composite shell, including the initial particle location, the hydrophilicity and the size of colloidal templates, the oil phase solvent and reserving time of emulsions after the addition of MF prepolymer, were further studied. Relatively uniform sized particle packed-droplets with an average diameter of 10 microm were obtained. The assembled SPS particles kept ordering and minimal conglutination after the preparation of composite microspheres, which allows of controlling the permeability from the interstices between the particles. Porous-mesh-structured MF composite layer was formed to further control the permeability. The morphology of emulsions and composite microspheres were characterized by optical microscopy, scanning and transmission electron microscopy.

  16. Preparation and evaluation of micro and meso porous silica monoliths with embedded carbon nanoparticles for the extraction of non-polar compounds from waters.

    Science.gov (United States)

    Fresco-Cala, Beatriz; Cárdenas, Soledad; Valcárcel, Miguel

    2016-10-14

    A novel hybrid micro and meso porous silica monolith with embedded carbon nanoparticles (Si-CNPs monolith) was prepared inside a fused silica capillary (3cm in length) and used as a sorbent for solid-phase microextraction. The hybrid monolithic capillary was synthetized by hydrolysis and polycondensation of a mixture of tetraethoxysilane (TEOS), ethanol, and three different carbon nanoparticles such as carboxylated single-walled carbon nanotubes (c-SWCNTs), carboxylated multi-walled carbon nanotubes (c-MWCNTs), and oxidized single-walled carbon nanohorns (o-SWNHs) via a two-step catalytic sol-gel process. Compared with silica monolith without carbon nanoparticles, the developed monolithic capillary column exhibited a higher extraction efficiency towards the analytes which can be ascribed to the presence of the carbon nanoparticles. In this regard, the best performance was achieved for silica monolith with embedded c-MWCNTs. The resulted monolithic capillaries were also characterized by scanning electron microscopy (SEM), elemental analysis and nitrogen intrusion porosimetry. Variables affecting to the preparation of the sorbent phase including three different carbon nanoparticles and extraction parameters were studied in depth using polycyclic aromatic hydrocarbons (PAHs) as target analytes. Gas chromatography-mass spectrometry was selected as instrumental technique. Detection limits range from 0.1 to 0.3μgL(-1), and the inter-extraction units precision (expressed as relative standard deviation) is between 5.9 and 14.4%.

  17. Preparation of highly porous binderless activated carbon electrodes from fibres of oil palm empty fruit bunches for application in supercapacitors.

    Science.gov (United States)

    Farma, R; Deraman, M; Awitdrus, A; Talib, I A; Taer, E; Basri, N H; Manjunatha, J G; Ishak, M M; Dollah, B N M; Hashmi, S A

    2013-03-01

    Fibres from oil palm empty fruit bunches, generated in large quantities by palm oil mills, were processed into self-adhesive carbon grains (SACG). Untreated and KOH-treated SACG were converted without binder into green monolith prior to N2-carbonisation and CO2-activation to produce highly porous binderless carbon monolith electrodes for supercapacitor applications. Characterisation of the pore structure of the electrodes revealed a significant advantage from combining the chemical and physical activation processes. The electrochemical measurements of the supercapacitor cells fabricated using these electrodes, using cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge-discharge techniques consistently found that approximately 3h of activation time, achieved via a multi-step heating profile, produced electrodes with a high surface area of 1704m(2)g(-1) and a total pore volume of 0.889cm(3)g(-1), corresponding to high values for the specific capacitance, specific energy and specific power of 150Fg(-1), 4.297Whkg(-1) and 173Wkg(-1), respectively.

  18. Ambient Filtration Method To Rapidly Prepare Highly Conductive, Paper-Based Porous Gold Films for Electrochemical Biosensing.

    Science.gov (United States)

    Guntupalli, Bhargav; Liang, Pingping; Lee, Jung-Hoon; Yang, Yuehai; Yu, Haixiang; Canoura, Juan; He, Jin; Li, Wenzhi; Weizmann, Yossi; Xiao, Yi

    2015-12-16

    Thin gold films offer intriguing material properties for potential applications including fuel cells, supercapacitors, and electronic and photonic devices. We describe here an ambient filtration method that provides a simple and novel way to generate rapidly porous and thin gold films without the need for sophisticated instruments, clean-room environments, and any postgrowth process or sintering steps. Using this approach, we can fabricate highly conductive gold films composed of gold nanoparticles layered atop a matrix of metallic single-walled carbon nanotubes on mixed cellulose ester filter paper within 20 min. These hybrid films (thickness ∼40 nm) exhibit fast electron transfer and excellent electrocatalytic properties that are similar to purchased gold films, but with a larger electroactive surface that lends itself to more sensitive analyte detection. We used the neurotransmitters dopamine and serotonin as benchmark analytes to demonstrate that our hybrid gold films can clearly discriminate the presence of both molecules in a mixture with resolution that greatly exceeds that of either purchased gold slides or electrodeposited gold films. Importantly, we postulate that this new approach could readily be generalized for the rapid fabrication of films from various other metals under ambient conditions, and could also be used as a prelude to transferring the resulting films onto glass or other flexible substrates.

  19. Electrolyte composition dependence of the morphological and nanostructural features of porous silicon prepared by electrochemical anodic etching

    Science.gov (United States)

    Kim, Hyo-Han; Son, Jong-Ick; Yun, Han-Sol; Cho, Nam-Hee

    2014-11-01

    Porous silicon layers were formed by electrochemical anodic etching of p-type Si wafers. The electrostatic condition at the interface between the Si wafers and electrolytes was affected sensitively by the addition of isopropyl alcohol (IPA) in the etchant. As the IPA ratio was varied in the range of 0 to 75%, the ideality factor in the ln I-V relationships and the viscosity of the electrolytes changed from 27.2 to 16.0, and from 1.0 to 3.3 cp, respectively. The etched surface exhibited three different morphologies, such as `turtle-back'-, `column'-, and `mountain'-like structures depending on the electrolyte composition. The etched layers contained Si nanocrystallites, 5.5 to 2.6 nm in size, which exhibited photoluminescence features in the wavelength range, 733 to 624 nm. The variation of the band gap was determined by size of the nanocrystallites, whereas the nanostructural and morphological features were dependent on the IPA ratios of the etchants.

  20. Encapsulation of biomaterials in porous glass-like matrices prepared via an aqueous colloidal sol-gel process

    Science.gov (United States)

    Liu, Dean-Mo; Chen, I-Wei

    2001-01-01

    The present invention provides a process for the encapsulation of biologically important proteins into transparent, porous silica matrices by an alcohol-free, aqueous, colloidal sol-gel process, and to the biological materials encapsulated thereby. The process is exemplified by studies involving encapsulated cytochrome c, catalase, myoglobin, and hemoglobin, although non-proteinaceous biomaterials, such as active DNA or RNA fragments, cells or even tissues, may also be encapsulated in accordance with the present methods. Conformation, and hence activity of the biomaterial, is successfully retained after encapsulation as demonstrated by optical characterization of the molecules, even after long-term storage. The retained conformation of the biomaterial is strongly correlated to both the rate of gelation and the subsequent drying speed of the encapsulatng matrix. Moreover, in accordance with this process, gelation is accelerated by the use of a higher colloidal solid concentration and a lower synthesis pH than conventional methods, thereby enhancing structural stability and retained conformation of the biomaterials. Thus, the invention also provides a remarkable improvement in retaining the biological activity of the encapsulated biomaterial, as compared with those involved in conventional alkoxide-based processes. It further provides new methods for the quantitative and qualitative detection of test substances that are reactive to, or catalyzed by, the active, encapsulated biological materials.

  1. Preparation of Immobilized Metal Affinity Chromatographic Packings Based on Monodisperse Hydrophilic Non-porous Beads and Their Application

    Institute of Scientific and Technical Information of China (English)

    BO Chun-Miao; GONG Bo-Lin; HU Wen-Zhi

    2008-01-01

    Three hydrophilic immobilized metal affinity chromatographic packings for HPLC have been synthesized by chemical modification of 3.0 μm monodisperse non-porous poly(glycidyl methacrylate-co-ethylenedimethacrylate)(PGMMEDMA)beads.The retention behavior of proteins on the metal ion chelated columns loaded with copper(Ⅱ),nickel(Ⅱ)and zin(Ⅱ)ion was studied.The effect of pH on the protein retention Was investigated on both the naked and metal ion chelated columns in the range from 4.0 to 9.0.Four proteins were quickly separated in 3.0 min with linear gradient elution at a flow rate of 3.0 mL/min by using the synthesized Ni2+ -IDA(iminodiacetic acid)packings.The separation time was shorter than other immobilized metal affinity chromatography reported in the literature.Purification of lysozyme from egg white and trypsin on the commercially available trypsin was performed on the naked-IDA and Cu2+ -IDA columns,respectively.The purities of the purified trypsin and lysozyme were more than 92%and 95%,respectively.

  2. Mechanical properties and in vitro biological response to porous titanium alloys prepared for use in intervertebral implants.

    Science.gov (United States)

    Caparrós, C; Guillem-Martí, J; Molmeneu, M; Punset, M; Calero, J A; Gil, F J

    2014-11-01

    The generation of titanium foams is a promising strategy for modifying the mechanical properties of intervertebral reinforcements. Thus, the aim of this study was to compare the in vitro biological response of Ti6Al4V alloys with different pore sizes for use in intervertebral implants in terms of the adhesion, proliferation, and differentiation of pre-osteoblastic cells. We studied the production of Ti6Al4V foams by powder metallurgy and the biological responses to Ti6Al4V foams were assessed in terms of different pore interconnectivities and elastic moduli. The Ti6Al4V foams obtained had similar porosities of approximately 34%, but different pore sizes (66 µm for fine Ti6Al4V and 147 µm for coarse Ti6Al4V) due to the sizes of the microsphere used. The Ti6Al4V foams had a slightly higher Young׳s modulus compared with cancellous bone. The dynamic mechanical properties of the Ti6Al4V foams were slightly low, but these materials can satisfy the requirements for intervertebral prosthesis applications. The cultured cells colonized both sizes of microspheres near the pore spaces, where they occupied almost the entire area of the microspheres when the final cell culture time was reached. No statistical differences in cell proliferation were observed; however, the cells filled the pores on fine Ti6Al4V foams but they only colonized the superficial microspheres, whereas the cells did not fill the pores on coarse Ti6Al4V foams but they were distributed throughout most of the material. In addition, the microspheres with wide pores (coarse Ti6Al4V) stimulated higher osteoblast differentiation, as demonstrated by the Alcaline Phosphatase (ALP) activity. Our in vitro results suggest that foams with wide pore facilitate internal cell colonization and stimulate osteoblast differentiation.

  3. Preparation of composite hollow fiber membranes: co-extrusion of hydrophilic coatings onto porous hydrophobic support structures

    NARCIS (Netherlands)

    He, T.; Mulder, M.H.V.; Strathmann, H.; Wessling, M.

    2002-01-01

    Coating a layer onto a support membrane can serve as a means of surface functionalization of membranes. Frequently, this procedure is a two-step process. In this paper, we describe a concept of membrane preparation in which a coating layer forms in situ onto a support membrane in one step by a co-ex

  4. 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.

  5. Preparation of nitrate-selective porous magnetic resin and assessment of its performance in removing nitrate from groundwater.

    Science.gov (United States)

    Liu, Cheng; Zhu, Lifei; Zhang, Qian; Chen, Wei

    2017-02-01

    Nitrate-selective, porous magnetic anion-exchange resin (NS-PMAER) with enhanced affinity and higher selectivity for nitrate was synthesized, characterized and its performance in nitrate removal was investigated. The results show that NS-PMAER consists of spherical particles with an average size of 200 μm. It has mean pore diameter, total pore volume, and BET specific surface area of 21.38 nm, 0.3605 cm(3)/g, and 67.455 m(2)/g, respectively. The specific saturation magnetization of NS-PMAER was about 10.79 emu/g. Fourier transform infrared spectrometer (FTIR) and X-ray photoelectron spectroscopy (XPS) results indicate that NS-PMAER has selectivity for nitrate higher than that of MIEX® resin; its coefficients of selectivity toward nitrate for nitrate and sulfate are 20.978 and 6.769, respectively, higher than those of MIEX® resin (1.256 and 4.342, respectively). Its working exchange capacity was 72.41 mg/mL. Column-exchange experiments' results suggest that it could be easily regenerated using 1.5 mol/L sodium chloride solution for a contact time of 30 min. Its recovery rate stayed at > 95% even after five rounds of recycling. Results of the pilot test indicate that NS-PMAER could effectively remove nitrate in groundwater, and ensure that nitrate concentrations of effluent to meet the guideline limit for drinking water by the World Health Organization.

  6. High sensitivity hydrogen sensing with Pt-decorated porous gallium nitride prepared by metal-assisted electroless etching.

    Science.gov (United States)

    Duan, Barrett K; Bohn, Paul W

    2010-05-01

    A unique hydrogen sensor structure based on Pt-decorated porous gallium nitride (PGaN) was fabricated by a two-step process consisting of metal-assisted electroless etching to produce PGaN with highly anisotropic pores followed by electroless deposition of Pt in the pores from an ammoniacal PtCl(6)(2-) solution. The Pt-decorated PGaN structure contains 50-100 nm diameter nanopores which are 400 nm to 1 microm deep and filled with Pt islands. Both electroless etching and deposition steps are done in solution and allow for large-scale production. An AC four-point probe conductivity measurement was implemented at f = 1 kHz, a frequency where the impedance of Pt-PGaN is nearly entirely resistive, and the change in conductance upon H(2) exposure was measured for three sample types: PGaN with a surface sputtered layer of Pt only; unetched GaN (CGaN) with both sputtered and electrolessly deposited Pt; and PGaN with both sputtered and electrolessly deposited Pt. The hydrogen sensing performance of the Pt-filled PGaN sensor was more than an order of magnitude better than either of the other two sample types under all experimental conditions, an observation attributed to the significant increase in Pt-GaN interfacial area in the electrolessly decorated PGaN samples, exhibiting a response to H2 concentrations as low as 1 ppm. The conductance changes are ascribed to adsorption-induced changes in interfacial polarization that produce changes in band bending and thus to the width of the space charge region near the Pt-GaN interface.

  7. Preparation and Passivation of Fine ε-CL-20%细粒度ε-CL-20的制备及钝化

    Institute of Scientific and Technical Information of China (English)

    任晓婷; 孙忠祥; 曹一林

    2011-01-01

    The fine ε-CL-20 was prepared by recrystalization with solvent-nonsolvent method. The feeding styles and categories of additives for controlling crystal growth on the crystal morphology and particle size were analyzed. The results show that they have great effect on the morphology, particle size and agglomeration in the crystallization process. Sonication process offers uniform crystalline morphology without any agglomeration and can decrease its mechanical properties. The particle size of fine CL-20 sample is around(16±l)μm,and its friction and impact sensitivity were 84% and 55. 1J,respectively,which were much more insensitive than the original products.%采用溶剂-非溶剂重结晶法制备了细粒度ε-CL-20,分析了加料方式、晶体生长控制剂种类等因素在结晶细化过程中对CL-20微晶形貌和粒度的影响.结果表明,上述几种因素对细粒度CL-20的形貌、粒径及聚集状态均有较大影响.采用超声波辅助技术可明显改善CL-20的晶体形貌和防止晶体团聚,显著降低产品的机械感度,所制备的ε-CL-20平均粒径为(16士1)μm、摩擦感度和撞击感度分别为84%和55.1J,明显优于原料.

  8. Preparation of three-layered porous PLA/PEG scaffold: relationship between morphology, mechanical behavior and cell permeability.

    Science.gov (United States)

    Scaffaro, R; Lopresti, F; Botta, L; Rigogliuso, S; Ghersi, G

    2016-02-01

    Interface tissue engineering (ITE) is used to repair or regenerate interface living tissue such as for instance bone and cartilage. This kind of tissues present natural different properties from a biological and mechanical point of view. With the aim to imitating the natural gradient occurring in the bone-cartilage tissue, several technologies and methods have been proposed over recent years in order to develop polymeric functionally graded scaffolds (FGS). In this study three-layered scaffolds with a pore size gradient were developed by melt mixing polylactic acid (PLA) and two water-soluble porogen agents: sodium chloride (NaCl) and polyethylene glycol (PEG). Pore dimensions were controlled by NaCl granulometry while PEG solvation created a micropores network within the devices. Scaffolds were characterized from a morphological and mechanical point of view in order to find a correlation between the preparation method, the pore architecture and compressive mechanical behavior. Biological tests were also performed in order to study the effect of pore size gradient on the permeation of different cell lines in co-culture. To imitate the physiological work condition, compressive tests were also performed in phosphate buffered saline (PBS) solution at 37°C. The presented preparation method permitted to prepare three-layered scaffolds with high control of porosity and pore size distribution. Furthermore mechanical behaviors were found to be strongly affected by pore architecture of tested devices as well as the permeation of osteoblast and fibroblast in-vitro.

  9. Preparation of PVAL/CMC Porous Composites by Microbial Foaming Method%酵母菌发泡PVAL/CMC多孔复合材料的制备

    Institute of Scientific and Technical Information of China (English)

    张敏; 杨鱼; 李成涛; 李八军; 刘智勇

    2016-01-01

    The polyvinyl alcohol(PVAL)/carboxymethylcellulose(CMC) porous composites were prepared by microbial foaming and cyclic freezing-thawing method. The yeast wasmixed into PVAL/CMC composites as microbial foaming agent. The effects of Y/G proportion,foaming time,foaming temperature,and CMC/PVAL proportion on porous composites were discussed by single factor experiments.L9(34) orthogonal test was adopted to optimize the foaming condition. The structures of PVAL/CMC porous composites were characterized by FTIR and SEM. The results show that when the foaming time is 60 min at 31℃, the proportion of CMC/PVAL is 0.7/1,the proportion of Y/G is 2.8/1,the foaming effect is best. The proportion of CMC/PVAL ratio is the most significant factor on the foaming behavior. In addition,the effect of Y/G ratio is also significant. SEM photographs show that the PVAL/CMC porous composites have high porosity,presenting open pore structures which large cells are sleeved by small cells.The average diameter of large cell and small cell is about 180μm and 15μm respectively.%采用微生物发泡法,将酵母菌作为微生物发泡剂,结合循环冷冻–解冻法制备聚乙烯醇(PVAL)/羧甲基纤维素(CMC)多孔复合材料。通过单因素试验探讨了酵母菌与葡萄糖比例(Y/G)、发泡时间、发泡温度和CMC与PVAL比例(CMC/PVAL)对发泡效果的影响,采用L9(34)正交试验进一步优化了发泡条件,通过傅立叶变换红外光谱和扫描电子显微镜(SEM)表征了PVAL/CMC多孔复合材料的结构。结果表明,当Y/G比例为2.8/1、发泡温度为31℃、发泡时间为60 min、CMC/PVAL比例为0.7/1时,PVAL/CMC多孔复合材料发泡效果最佳,其中CMC/PVAL比例为主要影响因素,此外,Y/G比例对发泡效果的影响也较为显著。SEM照片显示,以酵母菌为发泡剂制备的PVAL/CMC多孔复合材料具有较高的孔隙率,大孔平均孔径在180μm左右,小孔平均孔径在15

  10. Electrochemical Properties of Porous Co(OH){sub 2} Nano-flake Thin Film Prepared by Electro-deposition for Supercapacitor

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyeon Jeong; Jin, En Mei; Jeong, Sang Mun [Chungbuk National University, Cheongju (Korea, Republic of)

    2016-04-15

    Porous Co(OH){sub 2} nano-flake thin films were prepared by a potential-controlled electro-deposition technique at various deposition voltage (−0.75, −1.0, −1.2, and −1.4 V) on Ti-mesh substrates for supercapacitor application. The potential of electrode was controlled to regulate the film thickness and the amount of Co(OH){sub 2} nano-flake on the titanium substrate. The film thickness was shown to reach the maximum value of 34 μm at −1.4 V of electrode potential, where 17.2 g of Co(OH){sub 2} was deposited on the substrate. The specific discharge capacitances were measured to be 226, 370, 720, and 1008 mF cm{sup -2} in the 1st cycle corresponding to the films which were formed at −0.75, −1.0, −1.2, and −1.4 V of electrode potentials, respectively. Then the discharge capacities were decreased to be 206, 349, 586 and 866 mF/cm{sup 2}, where the persistency rates were 91, 94, 81, and 86%, respectively.

  11. Preparation of electrolyte thin film on NiO-YSZ porous substrate for solid oxide fuel cells by electrophoretic deposition (I)

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S.W.; Lee, B.H.; Son, Y.B.; Song, H.S. [Korea Institute of Science and Technology, Seoul (Korea)

    1999-05-01

    Yttria-stabilized zirconia(YSZ) thin films for an anode support type solid oxide fuel cell(SOFC) was prepared by electrophoretic deposition(EPD). Kinetic model and properties of electrolyte film obtained by EPD on porous NiO-YSZ substrate were investigated. In the constant current mode, the deposited weight increased with time and the curve was well-fitted by Dihyperbola type function. In constant voltage mode, the deposited weight saturated with time, and the curve was fitted by the modified Zhangs' equation. There was little difference in the weight and microstructure of films between constant current and constant voltage conditions in short time(under 30 s), but the surface of deposited film at constant current condition was more smooth than that at constant voltage condition. Although zirconia films, obtained under either conditions at low electric field for long time processing, contained defects such as sagging and crack, sagging of film at constant voltage condition was more sever than for constant current condition. YSZ thin film with uniform thickness of less than 10 {mu}m by EPD was formed at constant current, 0.035 mA/cm{sup 2} for 10 s. 19 refs., 12 figs.

  12. Structural, optical, and adsorption properties of ZnO(2)/poly(acrylic acid) hybrid thin porous films prepared by ionic strength controlled layer-by-layer method.

    Science.gov (United States)

    Pál, Edit; Sebok, Dániel; Hornok, Viktória; Dékány, Imre

    2009-04-01

    ZnO(2)/poly(acrylic acid) sandwich structures were prepared by layer-by-layer (LbL) self-assembly. The structure and optical behavior of the hybrid films were controlled by changing the surface charge and conformation of the poly(acrylic acid). The buildup of the films was followed by UV-vis absorption and reflection spectroscopy, atomic force microscopy (AFM), X-ray diffraction (XRD), and quartz crystal microbalance (QCM) measurements. It was found that the ionic strength of the polymer solution had a great influence on the film thickness which, in turn, affected the optical properties. The water vapor adsorption isotherms of the films determined by QCM showed an adsorption hysteresis characteristic of porous thin layer structures. The adsorption of water molecules inside the films changed the effective refractive index resulting in a change of the reflection properties. This phenomenon is shown to be exploited for the application of the films as optical sensors. The polarizability of water molecules in the adsorption layer was also determined. It was found that polarization of water molecules in the adsorption layer is much lower than in the liquid water when the surface coverage (Theta) is low.

  13. 电池级超微细磷酸铁的制备%Preparation of battery-grade ultra fine iron phosphates

    Institute of Scientific and Technical Information of China (English)

    彭爱国; 贺周初; 余长艳; 庄新娟; 闻杰; 汪永斌

    2013-01-01

    To explore a low cost synthesis process of iron phosphates,preparation of battery-grade ultra fine iron phosphates is discovered with ferrous sulfate as the raw material by ferrous sulfate oxidation reaction,basic iron phosphate precipitation reaction and basic iron phosphate conversion reaction.Influences of reaction temperature,feeding time of hydrogen peroxide and ammonium phosphate,feeding quantity of hydrogen peroxide and concentration of phosphoric acid etc.on the product quality were discussed.The optimal process conditions are that hydrogen peroxide feeding quantity is 120% and feeding time is 50 mins in oxidation reaction,reaction temperature is 40 ℃ ; ammonium phosphate feeding time is 40 mins in precipitation reaction,reaction temperature is 90 ℃ and concentration of phosphoric acid is 0.5 mol/L in conversion reaction.Battery-grade ultra fine iron phosphates with particle size less than 3.0 μm can be prepared under the optimum conditions,elemental analysis reveals that the content of metal impurities is less than 0.005%,sulphur content is less than 0.022%,and n(P)/n(Fe) is 1.01; the iron phosphates is highly pure product.X-ray diffraction test results show that the product without high-temperature treatment is amorphous ultra fine particles,and the product after being treated under high temperature of 600 ℃ has high crystallinity,and crystal is very perfect.%为了探索一种低成本的磷酸铁合成工艺,以硫酸亚铁为原料,经过硫酸亚铁氧化、碱式磷酸铁沉淀、碱式磷酸铁转化制备出电池级超微细磷酸铁.研究了硫酸亚铁氧化、碱式磷酸铁沉淀、碱式磷酸铁转化反应过程中反应温度、加料时间、磷酸浓度等因素对磷酸铁产品质量的影响.通过试验得到了合成磷酸铁的最佳工艺条件:氧化反应过氧化氢加料量为标准量的120%,加料时间50 min,沉淀反应温度40℃;磷酸铵加料时间40 min,转化反应温度90℃,磷酸浓度0.5 mol/L.

  14. Preparation, characterization and adsorption properties of a novel 3-aminopropyltriethoxysilane functionalized sodium alginate porous membrane adsorbent for Cr(III) ions.

    Science.gov (United States)

    Chen, Jian Hua; Xing, Hai Tao; Guo, Hong Xu; Li, Guo Ping; Weng, Wen; Hu, Shi Rong

    2013-03-15

    In this study, we prepared 3-aminopropyl-triethoxysilane (APTEOS) functionalized sodium alginate (SA) porous membrane adsorbent (APTEOS/SA) and tested its adsorption performance for removing of Cr(III) ions. The physico-chemical properties of the pristine and Cr(III) ions loaded APTEOS/SA were investigated by FT-IR, SEM-EDX, TG, AFM, and contact angle goniometer methods. To investigate the adsorption kinetics of Cr(III) ions onto this newly developed APTEOS/SA, we performed a batch of experiments under different adsorption conditions: solution pH, adsorbent dose, initial Cr(III) ion concentration, adsorption temperature, and contact time. The APTEOS/SA exhibited an encouraging uptake capacity of 90.0mg/g under suitable adsorption conditions. To study the mechanism of adsorption process, we examined the Lagergren pseudo-first-order and pseudo-second-order kinetic model, the intra-particular diffusion model, and the Crank model. Kinetics experiments indicated that the pseudo-first-order model displayed the best correlation with adsorption kinetics data. The Crank model showed that the intra-particle solute diffusion was the main rate-controlling step. Furthermore, our adsorption equilibrium data could be better described by the Freundlich equation. We also carried out consecutive adsorption-desorption experiments eight times to show that the APTEOS/SA has encouraging adsorption-desorption efficiencies. The results indicates that the prepared adsorbent is promising for using as an effective and economical adsorbent for Cr(III) ions removal.

  15. Porous TiO(2)/SiO(2) composite prepared using PEG as template direction reagent with assistance of supercritical CO(2).

    Science.gov (United States)

    Jiao, Jianxia; Xu, Qun; Li, Limin

    2007-12-15

    Titania-silica mesoporous composites have been prepared using polyethylene glycol (PEG) 20,000 as a template direction reagent with the assistance of supercritical carbon dioxide (SC CO(2)). For this preparation method, the composite precursors of tetrabutyl titanate (TBTT) and tetraethyl orthosilicate (TEOS) were dissolved in supercritical CO(2) and impregnated into PEG 20,000 using SC CO(2) as swelling agent and carrier. After removal of the PEG template by calcination in air at suitable temperatures, porous titania-silica composites were obtained. Effects of CO(2) pressure and temperature have been studied on the impregnation ratio during the supercritical fluid condition. The composite products were characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), FTIR spectroscopy, nitrogen sorption-desorption experiments, scanning electronic microscope (SEM), and transmission electron microscope (TEM). XRD and nitrogen sorption-desorption experimental results indicate that the titania-silica composite crystallized in anatase phase and has a preferable BET surface area up to 301.98 m(2)/g. It was also demonstrated that the microstructure and macroproperty of TiO(2)/SiO(2) composites depend strongly on the experimental pressure during the impregnation process in SC CO(2). At suitable CO(2) pressure, silica even can be found in a single crystalline structure in nature by observation of TEM. At the same time, SEM indicates that the composite product existed in a spheric form or a cubic form inserted with many holes. So this work provides a new route to control and obtain the special micrography of TiO(2)/SiO(2) composites with the aid of suitable polymer templates in supercritical CO(2).

  16. Preparation of porous hollow silica spheres via a layer-by-layer process and the chromatographic performance

    Science.gov (United States)

    Wei, Xiaobing; Gong, Cairong; Chen, Xujuan; Fan, Guoliang; Xu, Xinhua

    2017-03-01

    Hollow silica spheres possessing excellent mechanical properties were successfully prepared through a layer-by-layer process using uniform polystyrene (PS) latex fabricated by dispersion polymerization as template. The formation of hollow SiO2 micro-spheres, structures and properties were observed in detail by zeta potential, SEM, TEM, FTIR, TGA and nitrogen sorption porosimetry. The results indicated that the hollow spheres were uniform with particle diameter of 1.6 μm and shell thickness of 150 nm. The surface area was 511 m2/g and the pore diameter was 8.36 nm. A new stationary phase for HPLC was obtained by using C18-derivatized hollow SiO2 micro-spheres as packing materials and the chromatographic properties were evaluated for the separation of some regular small molecules. The packed column showed low column pressure, high values of efficiency (up to about 43 000 plates/m) and appropriate asymmetry factors.

  17. Near-Edge X-Ray Absorption Fine Structure of Ultrananocrystalline Diamond/Hydrogenated Amorphous Carbon Films Prepared by Pulsed Laser Deposition

    Directory of Open Access Journals (Sweden)

    Shinya Ohmagari

    2009-01-01

    Full Text Available The atomic bonding configuration of ultrananocrystalline diamond (UNCD/hydrogenated amorphous carbon (a-C:H films prepared by pulsed laser ablation of graphite in a hydrogen atmosphere was examined by near-edge X-ray absorption fine structure spectroscopy. The measured spectra were decomposed with simple component spectra, and they were analyzed in detail. As compared to the a-C:H films deposited at room substrate-temperature, the UNCD/a-C:H and nonhydrogenated amorphous carbon (a-C films deposited at a substrate-temperature of 550∘C exhibited enhanced ∗ and ∗C≡C peaks. At the elevated substrate-temperature, the ∗ and ∗C≡C bonds formation is enhanced while the ∗C–H and ∗C–C bonds formation is suppressed. The UNCD/a-C:H film showed a larger ∗C–C peak than the a-C film deposited at the same elevated substrate-temperature in vacuum. We believe that the intense ∗C–C peak is evidently responsible for UNCD crystallites existence in the film.

  18. Preparation and photochromic properties of ultra-fine H{sub 3}PW{sub 11}MoO{sub 40}/PVA fibre mats

    Energy Technology Data Exchange (ETDEWEB)

    Yang Guocheng; Gong Jian; Pan Yan; Cui Xiujun; Shao Changlu; Guo Yihang; Wen Shangbin; Qu Lunyu [Department of Chemistry, Northeast Normal University, Changchun 130024 (China)

    2004-07-21

    Novel photochromic materials, H{sub 3}PW{sub 11}MoO{sub 40}/Poly (vinyl alcohol) (PVA) ultra-fine fibre mats containing different weight percentages of H{sub 3}PW{sub 11}MoO{sub 40}, have been prepared from different H{sub 3}PW{sub 11}MoO{sub 40}/PVA solutions by an electrospinning technique. IR spectroscopy, wide-angle x-ray diffraction, and scanning electron microscope spectroscopy are used to characterize the fibre mats. Results of viscosity and conductivity measurements of the solutions indicate that lower viscosity and higher conductivity favour the formation of thin fibres without beads. When irradiated with ultraviolet light (313.2 nm), the colour of the fibre mats changes from white to blue, and the mats show reversible photochromism. IR and ESR spectra of the irradiated fibre mats indicate a conceivable photochromic mechanism, i.e. Mo{sup VI} is reduced under ultraviolet irradiation. Meanwhile, PVA is oxidized to unsaturated ketone or aldehyde.

  19. Multilayer porous structures of HVPE and MOCVD grown GaN for photonic applications

    Science.gov (United States)

    Braniste, T.; Ciers, Joachim; Monaico, Ed.; Martin, D.; Carlin, J.-F.; Ursaki, V. V.; Sergentu, V. V.; Tiginyanu, I. M.; Grandjean, N.

    2017-02-01

    In this paper we report on a comparative study of electrochemical processes for the preparation of multilayer porous structures in hydride vapor phase epitaxy (HVPE) and metal organic chemical vapor phase deposition (MOCVD) grown GaN. It was found that in HVPE-grown GaN, multilayer porous structures are obtained due to self-organization processes leading to a fine modulation of doping during the crystal growth. However, these processes are not totally under control. Multilayer porous structures with a controlled design have been produced by optimizing the technological process of electrochemical etching in MOCVD-grown samples, consisting of five pairs of thin layers with alternating-doping profiles. The samples have been characterized by SEM imaging, photoluminescence spectroscopy, and micro-reflectivity measurements, accompanied by transfer matrix analysis and simulations by a method developed for the calculation of optical reflection spectra. We demonstrate the applicability of the produced structures for the design of Bragg reflectors.

  20. Facile preparation of nitrogen-doped porous carbon from waste tobacco by a simple pre-treatment process and their application in electrochemical capacitor and CO{sub 2} capture

    Energy Technology Data Exchange (ETDEWEB)

    Sha, Yunfei; Lou, Jiaying [Technical Center, Shanghai Tobacco Group Co., Ltd., Shanghai 200082 (China); Bai, Shizhe [Department of Chemistry, Fudan University, Shanghai 200433 (China); Wu, Da, E-mail: wud@sh.tobacco.com.cn [Technical Center, Shanghai Tobacco Group Co., Ltd., Shanghai 200082 (China); Liu, Baizhan [Technical Center, Shanghai Tobacco Group Co., Ltd., Shanghai 200082 (China); Ling, Yun, E-mail: yunling@fudan.edu.cn [Department of Chemistry, Fudan University, Shanghai 200433 (China)

    2015-04-15

    Highlights: • A pre-treatment process is used to prepared N-doped carbon from waste biomass. • Waste tobaccos, which are limited for the disposal, are used as the raw materials. • The product shows a specific surface area and nitrogen content. • Its electrochemical performance is better than commercial activated carbon. • Its CO{sub 2} sorption performance is also better than commercial activated carbon. - Abstract: Preparing nitrogen-doped porous carbons directly from waste biomass has received considerable interest for the purpose of realizing the atomic economy. In this study, N-doped porous carbons have been successfully prepared from waste tobaccos (WT) by a simple pre-treatment process. The sample calcinated at 700 °C (WT-700) shows a micro/meso-porous structures with a BET surface area of 1104 m{sup 2} g{sup −1} and a nitrogen content of ca. 19.08 wt.% (EDS). Performance studies demonstrate that WT-700 displays 170 F g{sup −1} electrocapacitivity at a current density of 0.5 A g{sup −1} (in 6 M KOH), and a CO{sub 2} capacity of 3.6 mmol g{sup −1} at 0 °C and 1 bar, and a selectivity of ca. 32 for CO{sub 2} over N{sub 2} at 25 °C. Our studies indicate that it is feasible to prepare N-enriched porous carbons from waste natural crops by a pre-treatment process for potential industrial application.

  1. Porous silicon gettering

    Energy Technology Data Exchange (ETDEWEB)

    Tsuo, Y.S.; Menna, P.; Pitts, J.R. [National Renewable Energy Lab., Golden, CO (United States)] [and others

    1996-05-01

    The authors have studied a novel extrinsic gettering method that uses the large surface areas produced by a porous-silicon etch as gettering sites. The annealing step of the gettering used a high-flux solar furnace. They found that a high density of photons during annealing enhanced the impurity diffusion to the gettering sites. The authors used metallurgical-grade Si (MG-Si) prepared by directional solidification casing as the starting material. They propose to use porous-silicon-gettered MG-Si as a low-cost epitaxial substrate for polycrystalline silicon thin-film growth.

  2. [The preparation and characterization of fine dusts carried out in the Clinica del Lavoro di Milano in support of experimental studies].

    Science.gov (United States)

    Occella, E; Maddalon, G; Peruzzo, G F; Foà, V

    1999-01-01

    This paper aims to illustrate the conditions selected at the Clinica del Lavoro of the University of Milan to prepare and analyze a large number of fine dust samples produced over a period of about 50 years, that were initially used for studies within the Clinic performed in its own facilities, and since 1956 were sent to other Italian and overseas laboratories (Luxembourg, UK, Germany, Norway, Sweden, South Korea, USA). The total quantity of material distributed (with maximum size 7-10 microns) was about 2 kg and consisted of the following mineral and artificial compounds: quartz, HF-treated quartz, tridymite, HF-treated tridymite, cristobalite, chromite, anthracite, quartz sand for foundry moulds, sand from the Lybian desert, vitreous silica, pumice, cement, as well small quantities of metallic oxides, organic resins, chrysotile, crocidolite, fibres (vitreous, cotton and polyamidic). About half of the entire quantity of dusts produced consisted of partially HF-treated tridymite. Initially, research on the etiology of silicosis used quartz dust samples, simply sieved or ventilated (consisting of classes finer than 0.04 mm, containing a 15-20% respirable fraction). From 1956 to 1960 the dusts were produced by manual grinding in an agate mortar, below about 10 microns, starting from quartz from Quincinetto (near Ivrea, Province of Turin), containing about 99.5% quartz: particle size and composition were checked using an optical-petrographic technique, with identification of the free and total silica content. Subsequently, the dusts used for biological research were obtained by grinding coarse material with a cast iron pestle and planetary mills, agate and corundum jars. The grinding products were sized by means of centrifugal classification, using the selector developed by N. Zurlo, ensuring control of dust size both optically and by means of wet levigators and hydraulic classifiers (in cooperation with the Institute of Mines of Turin Polytechnic School). After 1990

  3. The preparation of porous alumina ceramics with directional pore channels structure by a camphene-based freeze-casting%莰烯基冷冻浇注成型法制备定向通孔氧化铝陶瓷

    Institute of Scientific and Technical Information of China (English)

    刘波涛; 骆兵; 许壮志; 刘贵山

    2011-01-01

    由莰烯、氧化铝、Texaphor 963组成的陶瓷料浆,在温度梯度的诱导下,用冷冻浇注成型法制备了氧化铝陶瓷坯体,经干燥、烧结后,制备出了高孔隙率、高强度的定向通孔氧化铝陶瓷.通过扫描电镜观察其孔结构,并对其孔隙率、抗压强度和收缩率进行分析测试.结果表明:料浆的固体含量和烧结温度显著影响试样的气孔率、抗压强度和收缩率;冷冻温度和烧结温度对最终的孔径分布和微观结构有较大影响.采用莰烯基冷冻浇注成型法可以制备定向通孔陶瓷材料,通过调整工艺参数来控制多孔陶瓷孔隙结构和性能,以满足不同需求.%The porous alumina ceramics was prepared by freezing the slurry system, which was constituted of camphene, alumina powder and Texaphor 963, then induced by temperature gradient, followed by drying and firing. The resultant porous ceramics had unique directional pore channels structure, high porosity and high compressive strength. The scanning electron microscope was used to observe its internal structure. The porosity, compressive strength and shrinkage of the porous ceramics were tested respectively. The results show that the solid loading of the slurry and sintering temperature have remarkable effects on porosity, compressive strength and shrinkage of porous alumina ceramics, freezing temperature and sintering temperature have greater influence on pore size distribution and fracture microstructure of porous alumina ceramics. The porous ceramics with directional pore channels structure can be prepared by a camphene-based freeze-casting technique, by adjusting process parameters to control the pore structure and properties of porous ceramics, in order to meet different needs of the user.

  4. Strategy and mechanism for controlling the direction of defect evolution in graphene: preparation of high quality defect healed and hierarchically porous graphene

    Science.gov (United States)

    Cao, Kecheng; Tian, Yin; Zhang, Yongzhi; Yang, Xiaodan; Bai, Chiyao; Luo, Yue; Zhao, Xiaosheng; Ma, Lijian; Li, Shoujian

    2014-10-01

    In this paper, a novel approach for controlling the direction of defect evolution in graphene through intercalation of organic small molecules into graphite oxide (GO) combined with a one-pot microwave-assisted reaction is reported. By using ethanol as intercalator, the bulk production of high quality graphene with its defects being satisfactorily healed is achieved. The repair of defects using extraneous carbon atoms and the hybrid state of these carbon atoms are definitely demonstrated using isotopic tracing studies with 13C-labeled ethanol combined with 13C solid-state NMR. The defect healed graphene shows excellent crystallinity, extremely low oxygen content (C : O ratio of 23.8) and has the highest sheet conductivity (61 500 S m-1) compared to all other reported graphene products derived from GO. By using methanol or benzene as intercalators, hierarchically porous graphene with a self-supported 3-dimensional framework (~917 m2 g-1) containing both macropores and mesopores (2-5 nm) is obtained. This graphene possesses a distinctive amorphous carbon structure around the edge of the nanopores, which could be conducive to enhancing the lithium storage performance (up to 580 mA h g-1 after 300 cycles) when tested as an anode of lithium ion batteries, and might have promising applications in the field of electrode materials, catalysis, and separation, and so on. The mechanism involved for the controlled defect evolution is also proposed. The simple, ultrafast and unified strategy developed in this research provides a practical and effective approach to harness structural defects in graphene-based materials, which could also be expanded for designing and preparing other ordered carbon materials with specific structures.In this paper, a novel approach for controlling the direction of defect evolution in graphene through intercalation of organic small molecules into graphite oxide (GO) combined with a one-pot microwave-assisted reaction is reported. By using ethanol as

  5. PREPARATION OF ORIENTED POROUS CERAMICS BY DIRECTIONAL SOLIDIFICATION AND FREEZE-DRYING METHOD%定向凝固和冷冻干燥制备定向多孔陶瓷

    Institute of Scientific and Technical Information of China (English)

    李利娟; 董寅生; 林萍华; 储成林; 盛晓波; 郭超

    2009-01-01

    采用定向凝固和冷冻干燥法制备定向多孔陶瓷材料,考察主要制备参数对多孔陶瓷材料性能的影响.以Al_2O_3,SiO_2为原料,Na_2O·SiO_2为添加剂,明胶为粘结剂,将陶瓷原料与蒸馏水混合制成浆料,预冻,冷冻干燥,烧结得到多孔陶瓷材料,通过扫描电镜观察其孔结构,并对其孔隙率和收缩率进行测试.制备过程中,浆料的固含量,冷冻温度,烧结温度对多孔陶瓷材料的孔隙率、收缩率、微观结构有较大影响.采用定向凝固和冷冻干燥法可以制备定向多孔陶瓷材料,通过控制工艺参数可以调整多孔陶瓷孔隙结构和性能,以满足不同需求.%Objectives To prepare oriented porous ceramics by directional solidification and freeze-drying method, the main preparation parameters that affect the properties of porous ceramics were investigated. Methods The solid materials, including alumina, silicon dioxide, sodium metassilicate and glutin, were mixed with distilled water at certain ratios to obtain slurry. The slurry was solidified directionally, freeze-dried and then sintered to get oriented porous ceramics. The microstructure of the porous ceramics was observed by scanning electron microscopy (SEM) and the properties were characterized by shrinkage and porosity. Results The solid content of slurry, the freezing and sintering temperatures affected the microstructure, shrinkage and porosity of the porous ceramics. Conclusion Oriented porous ceramics can be successfully prepared by directional solidification and freeze-drying method. By controlling the technique parameters, the pore structure and properties can be adjusted to satisfy different needs.

  6. An assessment of geochemical preparation methods prior to organic carbon concentration and carbon isotope ratio analyses of fine-grained sedimentary rocks

    Science.gov (United States)

    KöNitzer, Sven F.; Leng, Melanie J.; Davies, Sarah J.; Stephenson, Michael H.

    2012-09-01

    This study summarizes organic carbon isotope (δ13C) and total organic carbon (TOC) data from a series of tests undertaken to provide an appropriate methodology for pre-analysis treatment of mudstones from an Upper Carboniferous sedimentary succession, in order to develop a consistent preparation procedure. The main treatments involved removing both inorganic carbonate and hydrocarbons (which might be extraneous) before δ13C and TOC analysis. The results show that decarbonating using hydrochloric acid causes significant reduction in δ13C and total carbon (TC) of the bulk material due to the removal of inorganic carbonate. These changes are most pronounced where soluble calcium carbonate (rather than Ca-Mg-Fe carbonate) is present. Deoiled samples show only slightly higher mean δ13C where visible bitumen was extracted from the bulk sample. Moreover, the isotopic signatures of the extracts are closely correlated to those of their respective bulk samples, suggesting that small yields of hydrocarbons were generated in situ with no isotopic fractionation. In addition, further δ13C and TC analyses were performed on samples where mixing of oil-based drilling mud with brecciated core material had been undertaken. Brecciated mudstone material did not display distinct isotopic signals compared to the surrounding fine-grained material. Overall we show that the most accurate assessment of bulk organic carbon isotopes and concentration in these samples can be achieved through decarbonating the material prior to measurement via the `rinse method'. However, our results support recent findings that pre-analysis acid treatments can cause variable and unpredictable errors in δ13C and TOC values. We believe that, despite these uncertainties, the findings presented here can be applied to paleoenvironmental studies on organic matter contained within sedimentary rocks over a range of geological ages and compositions.

  7. Porous structure and Cr(VI) removal abilities of Fe{sub 3}O{sub 4} prepared from Fe-urea complex

    Energy Technology Data Exchange (ETDEWEB)

    Asuha, S., E-mail: asuha42@yahoo.com.cn [Chemistry and Environment Science College, Inner Mongolia Normal University, and Key Laboratory of Physics and Chemistry of Function Materials, Inner Mongolia, 81 Zhaowudalu, Huhhot 010022 (China); Suyala, B.; Zhao, S. [Chemistry and Environment Science College, Inner Mongolia Normal University, and Key Laboratory of Physics and Chemistry of Function Materials, Inner Mongolia, 81 Zhaowudalu, Huhhot 010022 (China)

    2011-09-15

    Highlights: {yields} Solvothermal reaction of [Fe(CON{sub 2}H{sub 4}){sub 6}](NO{sub 3}){sub 3} can produce mesoporous Fe{sub 3}O{sub 4}. {yields} The mesoporous Fe{sub 3}O{sub 4} shows high removal ability for Cr(VI). {yields} The adsorption of Cr(VI) on the Fe{sub 3}O{sub 4} can be well described by Langmuir model. - Abstract: In this work, the porous structure and the Cr(VI) removal abilities of the magnetite (Fe{sub 3}O{sub 4}) nanopowder prepared by one-pot solvothermal reaction of Fe-urea complex ([Fe(CON{sub 2}H{sub 4}){sub 6}](NO{sub 3}){sub 3}) were investigated. Low-angle X-ray diffraction (XRD), nitrogen adsorption-desorption measurements, and transmission electron micrograph (TEM) observations show that the Fe{sub 3}O{sub 4} has a mesoporous structure with an average pore size of 5.3 nm and BET surface area of 120 m{sup 2}/g. The removal of gaseous species including CON{sub 2}H{sub 4}, NO, NO{sub 2} and O{sub 2} during the formation of the Fe{sub 3}O{sub 4} are considered to be the most probable reason for the formation of mesoporous structure. The adsorption behavior of Cr(VI) on the mesoporous Fe{sub 3}O{sub 4} can be well described by Langmuir adsorption model, and the maximum adsorption capacity for Cr(VI) is estimated to be 15.4 mg/g.

  8. Integrin-mediated osteoblastic adhesion on a porous manganese-incorporated TiO2 coating prepared by plasma electrolytic oxidation.

    Science.gov (United States)

    Zhang, Zhenxiang; Gu, Beibei; Zhu, Wei; Zhu, Lixian

    2013-09-01

    This study was conducted to evaluate the bioactivity of manganese-incorporated TiO2 (Mn-TiO2) coating prepared on titanium (Ti) plate by plasma electrolytic oxidation (PEO) technique in Ca-, P- and Mn-containing electrolytes. The surface topography, phase and element compositions of the coatings were investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive spectrometry (EDS), respectively. The adhesion of osteoblast-like MG63 cells onto Ti, TiO2 and Mn-TiO2 surfaces was evaluated, and the signal transduction pathway involved was confirmed by the sequential expression of the genes for integrins β1, β3, α1 and α3, focal adhesion kinase (FAK), and the extracellular regulated kinases (ERKs), including ERK1 and ERK2. The results obtained indicated that Mn was successfully incorporated into the porous nanostructured TiO2 coating, and did not alter the surface topography or the phase composition of the coating. The adhesion of the MG63 cells onto the Mn-incorporated TiO2 coating was significantly enhanced compared with that on the Mn-free TiO2 coating and the pure Ti plates. In addition, the enhanced cell adhesion on the Mn-TiO2 coatings may have been mediated by the binding of the integrin subunits, β1 and α1, and the subsequent signal transduction pathway, involving FAK and ERK2. The study indicated that the novel Mn-TiO2 coating has potential for orthopedic implant applications, and that further investigations are required.

  9. Strategy and mechanism for controlling the direction of defect evolution in graphene: preparation of high quality defect healed and hierarchically porous graphene.

    Science.gov (United States)

    Cao, Kecheng; Tian, Yin; Zhang, Yongzhi; Yang, Xiaodan; Bai, Chiyao; Luo, Yue; Zhao, Xiaosheng; Ma, Lijian; Li, Shoujian

    2014-11-21

    In this paper, a novel approach for controlling the direction of defect evolution in graphene through intercalation of organic small molecules into graphite oxide (GO) combined with a one-pot microwave-assisted reaction is reported. By using ethanol as intercalator, the bulk production of high quality graphene with its defects being satisfactorily healed is achieved. The repair of defects using extraneous carbon atoms and the hybrid state of these carbon atoms are definitely demonstrated using isotopic tracing studies with (13)C-labeled ethanol combined with (13)C solid-state NMR. The defect healed graphene shows excellent crystallinity, extremely low oxygen content (C : O ratio of 23.8) and has the highest sheet conductivity (61 500 S m(-1)) compared to all other reported graphene products derived from GO. By using methanol or benzene as intercalators, hierarchically porous graphene with a self-supported 3-dimensional framework (∼917 m(2) g(-1)) containing both macropores and mesopores (2-5 nm) is obtained. This graphene possesses a distinctive amorphous carbon structure around the edge of the nanopores, which could be conducive to enhancing the lithium storage performance (up to 580 mA h g(-1) after 300 cycles) when tested as an anode of lithium ion batteries, and might have promising applications in the field of electrode materials, catalysis, and separation, and so on. The mechanism involved for the controlled defect evolution is also proposed. The simple, ultrafast and unified strategy developed in this research provides a practical and effective approach to harness structural defects in graphene-based materials, which could also be expanded for designing and preparing other ordered carbon materials with specific structures.

  10. 钛酸钾晶须耐碱多孔陶瓷的制备及表征%Preparation and Characterization of Alkaline Resistant Porous Ceramics from Potassium Titanate Whiskers

    Institute of Scientific and Technical Information of China (English)

    周亚新; 刘畅; 何明; 杨祝红; 冯新; 陆小华

    2007-01-01

    The preparation and characterization of alkaline resistant porous ceramics from potassium titanate whiskers are studied. K2Ti4O9 whiskers in the whisker preforms (mixtures of K2Ti6O13 and K2Ti4O9) were completely converted to K2Ti6O13 at 960℃. The alkaline resistance as well as the change in bending strength, porosity and permeability of the ceramics was investigated by altering the composition of the preforms in which the content of K2Ti6O13 whiskers was higher than 50% (molar fraction). The alkaline resistance of the porous K2Ti6O13 ceramics is found much higher than that of Al2O3 in caustic NaOH solutions, and further study indicates that the K2Ti6O13ceramics can be stably used in solutions of pH>2.0. The bending strength increases initially with the content of the raw K2Ti6O13 in the preforms up to 66% (molar fraction) and then decreases, contrary to the behaviors of porosity and permeability. The values of bending strength, porosity and permeability of the ceramics prepared from the precomparable to those of the porous Al2O3 ceramics.

  11. Preparation, in vitro degradability, cytotoxicity, and in vivo biocompatibility of porous hydroxyapatite whisker-reinforced poly(L-lactide) biocomposite scaffolds.

    Science.gov (United States)

    Xie, Lu; Yu, Haiyang; Yang, Weizhong; Zhu, Zhuoli; Yue, Li

    2016-01-01

    Biodegradable and bioactive scaffolds with interconnected macroporous structures, suitable biodegradability, adequate mechanical property, and excellent biocompatibility have drawn increasing attention in bone tissue engineering. Hence, in this work, porous hydroxyapatite whisker-reinforced poly(L-lactide) (HA-w/PLLA) composite scaffolds with different ratios of HA and PLLA were successfully developed through compression molding and particle leaching. The microstructure, in vitro mineralization, cytocompatibility, hemocompatibility, and in vivo biocompatibility of the porous HA-w/PLLA were investigated for the first time. The SEM results revealed that these HA-w/PLLA scaffolds possessed interconnected pore structures. Compared with porous HA powder-reinforced PLLA (HA-p/PLLA) scaffolds, HA-w/PLLA scaffolds exhibited better mechanical property and in vitro bioactivity, as more formation of bone-like apatite layers were induced on these scaffolds after mineralization in SBF. Importantly, in vitro cytotoxicity displayed that porous HA-w/PLLA scaffold with HA/PLLA ratio of 1:1 (HA-w1/PLLA1) produced no deleterious effect on human mesenchymal stem cells (hMSCs), and cells performed elevated cell proliferation, indicating a good cytocompatibility. Simultaneously, well-behaved hemocompatibility and favorable in vivo biocompatibility determined from acute toxicity test and histological evaluation were also found in the porous HA-w1/PLLA1 scaffold. These findings may provide new prospects for utilizing the porous HA whisker-based biodegradable scaffolds in bone repair, replacement, and augmentation applications.

  12. 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.

  13. Mechanical and frictional behaviour of nano-porous anodised aluminium

    Energy Technology Data Exchange (ETDEWEB)

    Tsyntsaru, N., E-mail: tintaru@phys.asm.md [Institute of Applied Physics of ASM, 5 Academy str., Chisinau, MD 2028 (Moldova, Republic of); Kavas, B., E-mail: bkavas@ford.com.tr [Istanbul Technical University, Department of Metallurgical and Materials Engineering, 34469 Maslak (Turkey); Ford Otomotiv San A.S., Istanbul (Turkey); Sort, J., E-mail: jordi.sort@uab.cat [Institució Catalana de Recerca i Estudis Avançats (ICREA) and Departament de Física, Universitat Autònoma de Barcelona, E-08193 Bellaterra (Spain); Urgen, M., E-mail: urgen@itu.edu.tr [Istanbul Technical University, Department of Metallurgical and Materials Engineering, 34469 Maslak (Turkey); Celis, J.-P., E-mail: jean-pierre.celis@mtm.kuleuven.be [KU Leuven, Dept. MTM, Kasteelpark Arenberg 44, B-3001 (Belgium)

    2014-12-15

    The porous structure of anodic aluminium oxide (AAO) can be used in versatile applications such as a lubricant reservoir in self-lubricating systems. Such systems are subjected to biaxial loading, which can induce crack formation and propagation, ultimately leading to catastrophic mechanical failure. In this study, the mechanical and tribological behaviour of AAO, prepared from two different types of electrolytes (sulphuric and oxalic acids), are studied in detail. The electrolytic conditions are adjusted to render highly tuneable average pore diameters (between 16 and 75 nm), with porosity levels ranging from 9% to 65%. Well-ordered porous AAO are produced by two-step anodization at rather low temperatures. Mechanical properties, mainly hardness and Young's modulus, are investigated using nanoindentation. Both the porosity degree and the composition of the electrolytic baths used to prepare the AAO have an influence on the mechanical properties. Ball-on-flat configuration was used to estimate the tribological behaviour under dry conditions. No major cracks were observed by scanning electron microscopy, neither after indentation or fretting tests. In the running-in period of tribology experiments the pores were filled with debris. This was followed by the formation of a highly adherent tribolayer – a third body consisting of fine worn particles originated from both the sample and the counterbody. Pore diameter and porosity percentage are found to strongly affect hardness and Young's modulus, but they do not have a major effect on the frictional behaviour. - Highlights: • Well-ordered porous AAO with pore diameters between 16 and 75 nm were produced. • Porosity and composition of electrolytic baths influence the mechanical properties. • Ball-on-flat configuration was used in tribological testing under dry conditions. • Adherent tribolayer consisting of fine worn particles prevents AAO from cracking. • Testing parameters are moreover essential

  14. Contribution to the study of the production and properties of finely divided solids, prepared in a flame reactor (1960); Contribution a l'etude de procedes d'obtention et des proprietes des solides finement divises elabores dans un reacteur a flamme (1960)

    Energy Technology Data Exchange (ETDEWEB)

    Cuer, J.P. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1960-04-15

    Sufficiently fine particles cannot be obtained by the grinding of crystals. It is therefore logical to adopt a method whereby the solid is formed from a compound in the vapour phase notable amongst such compounds, volatile at moderate temperatures, are certain organic derivatives of metals and the metallic halides. Formation of the solid from its gaseous derivative should be possible by hydrolysis or oxidation without the dispersion of the reaction medium being modified. The simplest method seems to be to obtain the reaction in an oxy-hydrogen blow-pipe. When the gases in the blow-pipe contain a volatile metallic compound, precipitation of finely divided solid in the form of oxide is produced in the flame at high temperature. Aluminium, titanium, iron and zirconium oxides and silica, the particles of which are spherical and very homogeneous in diameter, have been prepared in this way. The specific surfaces calculated from the diameters on electron microscope photographs are in agreement with those measured by adsorption of nitrogen at 195 deg. C. The oxides thus prepared are therefore not intensely porous. The properties and size of the oxide particles are studied as a function of various operational parameters, such as flame temperature and concentration of volatile metal derivative in the reactive gases. When the blow-pipe is supplied with oxide particles of small diameter, a very marked increase in size is observed. The properties of these preparations are also examined. (author) [French] Les procedes de broyage des cristaux ne conduisent pas a des particules suffisamment fines. Aussi, il est logique de s'adresser a un procede de formation du solide a partir d'un compose se trouvant en phase vapeur. De tels composes, volatils a des temperatures moderees, sont notamment certains derives organiques des metaux et les halogenures metalliques. La formation du solide a partir de son derive gazeux doit pouvoir etre effectuee par l'hydrolyse ou l

  15. Effect of Y{sub 2}O{sub 3} addition on the properties of mullite bonded porous SiC ceramics prepared by an infiltration technique

    Energy Technology Data Exchange (ETDEWEB)

    Kayal, N.; Dey, O.; Chakrabarti, O.

    2013-10-01

    Mullite bonded porous SiC ceramics were synthesized by infiltrating a powder compact of SiC and Y{sub 2}O{sub 3} with a liquid precursor of mullite which on subsequent heat treatment at 1300-1500 degree centigrade produced mullite bonded porous SiC ceramics. The effect of Y{sub 2}O{sub 3} content and sintering temperature on phase composition, microstructure, oxidation degree of SiC, flexural strength, porosity and pore size distribution were studied. Due to enhance oxidation and well developed neck formation by the addition of Y{sub 2}O{sub 3} a high strength 49 MPa was achieved for the porous mullite bonded SiC ceramics with porosity 28 vol %. (Author)

  16. Progress in Preparation Methods of Porous TiO2 Thin Films%多孔 TiO2薄膜的制备研究进展

    Institute of Scientific and Technical Information of China (English)

    王达; 刘建敏; 周曦亚

    2012-01-01

    The preparation methods of porous TiO2 thin films,such as liquid phase ways (Including sol-gel, evaporation-induced self-assembly,etc ) , physical vapor deposition ways(Including magnetron sputtering, electron beam evaporation deposition,etc. ), electrochemical ways (Including anodic oxidation, micro-arc oxidation,etc. ) are summarized, and the preparing theory is introduced respectively. Different ways of preparing porous TiO2 thin films have great difference in surface topography, aperture size, tropism and wall of hole thickness aspect The problems in synthesizing porous TiO2 thin films and research direction in the future are pointed out at last.%综述了液相法(包括溶胶-凝胶法、蒸发诱导自组装法等)、电化学法(包括阳极氧化法、微弧氧化法等)、物理气相法(包括磁控溅射法、电子束蒸发法等)、化学气相法等制备多孔TiO2薄膜的方法,介绍了相应的合成原理,指出不同方法制备的多孔TiO2薄膜在表面形貌、孔径尺寸、取向和孔壁厚度等方面存在很大差异.通过对比不同制备方法的优缺点并结合工业化生产成本,提出了今后多孔TiO2薄膜制备技术的发展方向,并展望了多孔TiO2薄膜广阔的应用前景.

  17. Anne Fine

    Directory of Open Access Journals (Sweden)

    Philip Gaydon

    2015-04-01

    Full Text Available An interview with Anne Fine with an introduction and aside on the role of children’s literature in our lives and development, and our adult perceptions of the suitability of childhood reading material.Since graduating from Warwick in 1968 with a BA in Politics and History, Anne Fine has written over fifty books for children and eight for adults, won the Carnegie Medal twice (for Goggle-Eyes in 1989 and Flour Babies in 1992, been a highly commended runner-up three times (for Bill’s New Frock in 1989, The Tulip Touch in 1996, and Up on Cloud Nine in 2002, been shortlisted for the Hans Christian Andersen Award (the highest recognition available to a writer or illustrator of children’s books, 1998, undertaken the positon of Children’s Laureate (2001-2003, and been awarded an OBE for her services to literature (2003. Warwick presented Fine with an Honorary Doctorate in 2005.Philip Gaydon’s interview with Anne Fine was recorded as part of the ‘Voices of the University’ oral history project, co-ordinated by Warwick’s Institute of Advanced Study.

  18. A controllable ionic liquid-assisted hydrothermal route to prepare CoCO{sub 3} crystals and their conversion to porous Co{sub 3}O{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Li, Haobo; Duan, Xiaochuan; Ma, Jianmin; Zheng, Wenjun [Department of Materials Chemistry and Key Laboratory of Advanced Energy Materials Chemistry MOE, College of Chemistry, Nankai University, Tianjin (China)

    2012-01-15

    In this work, we have synthesized CoCO{sub 3} microaggregation, microcubes and nanoplates by an ionic liquid-assisted hydrothermal method. The morphologies of the CoCO{sub 3} crystals depend on the concentration of the ionic liquid and the reaction temperature. Moreover, the as-prepared CoCO{sub 3} crystals can serve as a useful precursor to obtain porous Co{sub 3}O{sub 4} particles with similar morphology by means of calcinations. (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  19. Photocatalytic activities of wet oxidation synthesized ZnO and ZnO-TiO2 thick porous films

    Science.gov (United States)

    Chen, Ruiqun; Han, Jie; Yan, Xiaodong; Zou, Chongwen; Bian, Jiming; Alyamani, Ahmed; Gao, Wei

    2011-05-01

    Highly porous zinc oxide (ZnO) film was produced by using reactive magnetron sputtering zinc target followed by wet oxidation. Titanium dioxide (TiO2) was mixed to the porous films by using either TiO2 target magnetron sputter deposition or sol-spin method. The film thickness could reach 50 μm with uniform porosity. On the sputtering prepared ZnO-TiO2 film surface, fine nanorods with small anatase TiO2 nano-clusters on the tips were observed by SEM and TEM, and the titanium (Ti) composition was determined by XPS as 0.37%. The sol-spin treatment could increase the Ti composition to 4.9%, with reduced pore size compared to the untreated ZnO porous film. Photoluminescence measurements showed that the Ti containing porous film has strong ultraviolet-visible light emission. In the photo-catalysis testing, ZnO and ZnO-TiO2 have similar photo-catalysis activity under 365 nm UV irradiation, but under visible light, the photocatalysis activities of ZnO-TiO2 films were twice higher than that of ZnO porous film, implying promising applications of this porous oxide composite for industrial and dairy farm wastewater treatment.

  20. Preparation of Honeycomb-like Porous 316L Stainless Steel by Selective Laser Melting%蜂窝状多孔316L不锈钢的选区激光熔化制备

    Institute of Scientific and Technical Information of China (English)

    王志阳; 沈以赴; 顾冬冬; 于秀平

    2011-01-01

    对含预合金316L不锈钢和NH4HCO3(质量比96:4)的混合粉末进行选区激光熔化,制备多孔材料的实验研究.利用扫描电镜分析试样的微观孔隙特征.结果表明,在较高激光功率(800 W)条件下,可形成蜂窝状的多孔结构,孔径分布均匀(2~5 μm),平均孔径约3.5 μm.分析激光功率对多孔结构特征的影响,讨论选区激光熔化蜂窝状多孔结构的形成机制.%The selective laser melting of a blended powder system consisting of 96wt% 316L stainless steel and 4wt% NH4HCO3 was performed to prepare porous materials.The SEM characterizations show the formation of a honeycomb-like porous structure at a relatively high laser power of 800 W.The pore sizes of the porous structure distribute homogeneously, typically in a range of 2-5 μm.The average pore size is about 3.5 μm.The effects of laser power on the microstructural characteristics of the as-obtained microcellular structures were investigated.The formation mechanisms of the honeycomb-like porous structure during selective laser melting were also discussed.

  1. Porous substrates filled with nanomaterials

    Science.gov (United States)

    Worsley, Marcus A.; Baumann, Theodore F.; Satcher, Jr., Joe H.; Stadermann, Michael

    2014-08-19

    A composition comprising: at least one porous carbon monolith, such as a carbon aerogel, comprising internal pores, and at least one nanomaterial, such as carbon nanotubes, disposed uniformly throughout the internal pores. The nanomaterial can be disposed in the middle of the monolith. In addition, a method for making a monolithic solid with both high surface area and good bulk electrical conductivity is provided. A porous substrate having a thickness of 100 microns or more and comprising macropores throughout its thickness is prepared. At least one catalyst is deposited inside the porous substrate. Subsequently, chemical vapor deposition is used to uniformly deposit a nanomaterial in the macropores throughout the thickness of the porous substrate. Applications include electrical energy storage, such as batteries and capacitors, and hydrogen storage.

  2. Preparation and thermodynamics characterization of micro-porous TiC%TiC微孔陶瓷的制备及其热力学表征

    Institute of Scientific and Technical Information of China (English)

    罗勇; 田茂财; 杨莉

    2012-01-01

    Material thermodynamics is used to analyze the carburization of titanium alloy for the purpose of research on the formation mechanism of micro-porous TiC ceramics. And then TiC miero-porous ceramics are successfully synthesized on the surface of titanium alloys using se- quential carburization. Finally, the properties of micro-porous TiC ceramics are examined. It is found that the sequential carburization is thermodynamically feasible, and graphite is obtained after the carburization. It also reveals that the high hardness could provide excellent support to the titanium alloy substrate. The results show that compact micro-porous titanium carbide with a face-centred cubic structure has high hardness value of 16.1 GPa, which indicates that micro --porous TiC ceramics is a potential biomaterial due to its excellent protection of the titanium substrate.%为了研究TiC微孔陶瓷的形成机理,采用材料热力学分析了钛合金的渗碳工艺,采用分级渗碳法在钛合金表面制备出了TiC微孔陶瓷,并对微孔陶瓷进行了性能表征.研究后认为钛合金分级渗碳在热力学上可行,同时在分级渗碳中得到的是石墨碳;其硬度很高能够对钛合金形成很好的支撑作用.结果表明:面心立方结构的碳化钛微孔陶瓷的纳米硬度值达到了16.1GPa,将对钛合金基体起到很好的保护作用,是一种很有前途的生物材料.

  3. Preparation and characterization of zirconia-yttria porous ceramics with addition of potassium iodide; Preparacao e caracterizacao de ceramicas porosas de zirconia-itria com adicao de iodeto de potassio

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, S.G.M.; Muccillo, R., E-mail: sabrina.carvalho@usp.br, E-mail: muccillo@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP/CCTM), Sao Paulo, SP (Brazil). Centro de Ciencia e Tecnologia de Materiais

    2012-07-01

    Porous zirconia stabilized with 8 mol% of yttria were prepared by adding different amounts of KI followed by its removal upon sintering. The thermal removal was evaluated by thermogravimetric and differential thermal analysis and dilatometric measurements. The samples were prepared and sintered at 1400 deg C/2h. All samples were characterized by X-ray diffraction and topographic analysis of polished and thermally etched surface to evaluate pore content. The additive content was evaluated by X-ray fluorescence analysis, showing that KI was removed during sintering. The electrical behavior was analyzed by impedance spectroscopy. The X- ray diffraction analyses show that all samples are single phase, cubic fluorite-type. The impedance diagrams allowed evaluating the increase in intergranular and intragranular resistivity with increasing content of pores. (author)

  4. Porous bioactive materials

    Science.gov (United States)

    Zhang, Kai

    Bioactive materials chemically bond to tissues through the development of biologically active apatite. Porous structures in biomaterials are designed to enhance bioactivity, grow artificial tissues and achieve better integration with host tissues in the body. The goal of this research is to design, fabricate and characterize novel porous bioactive materials. 3D ordered macroporous bioactive glasses (3DOM-BGs, pore size: 200--1000 nm) were prepared using a sol-gel process and colloidal crystal templates. 3DOM-BGs are more bioactive and degradable than mesoporous (pore size simulated body fluid (SBF). Apatite formation and 3DOM-BG degradation rates increased with the decrease of soaking ratio. Apatite induction time in SBF increased with 3DOM-BG calcination temperature (600--800°C). Apatite formation and 3DOMBG degradation were slightly enhanced for a phosphate containing composition. Large 3DOM-BG particles formed less apatite and degraded less completely as compared with small particles. An increase in macropore size slowed down 3DOM-BG degradation and apatite formation processes. After heating the converted apatite at a temperature higher than 700°C, highly crystalline hydroxyapatite and a minor tri-calcium phosphate phase formed. 3DOM-BGs have potential applications as bone/periodontal fillers, and drugs and biological factors delivery agents. Anchoring artificial soft tissues (e.g., cartilage) to native bone presents a challenge. Porous polymer/bioactive glass composites are candidate materials for engineering artificial soft tissue/bone interfaces. Porous composites consisting of polymer matrices (e.g., polysulfone, polylactide, and polyurethane) and bioactive glass particles were prepared by polymer phase separation techniques adapted to include ceramic particles. Composites (thickness: 200--500 mum) have asymmetric structures with dense top layers and porous structures beneath. Porous structures consist of large pores (>100 mum) in a network of smaller (<10

  5. 多孔金属氧化物半导体薄膜的制备及光催化性能%Preparation and Photocatalytic Activity of Porous Metal Oxides Films

    Institute of Scientific and Technical Information of China (English)

    吴朵朵; 鲍艳; 马建中; 田万乐

    2016-01-01

    以垂直蒸发沉积法制备的聚苯乙烯(PS)胶态晶体为模板,采用溶胶–凝胶法制备多孔 ZnO 和 TiO2薄膜,分别考察其对罗丹明 B(RhB)溶液的光催化降解效果。使用扫描电子显微镜观察 PS 胶态晶体以及多孔 ZnO 和 TiO2薄膜的形貌,以紫外–可见吸收光谱仪表征光催化降解效果。结果表明:PS 微球分散液浓度为0.025%时,胶态晶体为单层和多层结构,随着浓度增加至0.100%,胶态晶体呈现完善的多层结构;PS 微球分散液浓度为0.100%、ZnO 溶胶浓度为0.3 mol/L 制备的多孔 ZnO 薄膜对 RhB 降解效果较好;PS 微球分散液浓度为0.025%、TiO2溶胶浓度为0.1 mol/L 获得的多孔 TiO2薄膜对 RhB 降解效果较好。多孔 ZnO 薄膜对 RhB 的降解效果优于多孔 TiO2薄膜。%Porous ZnO and TiO2 films were fabricated by a sol-gel method with polystyrene colloidal crystal as a template, which was prepared via a vertical deposition method. The effect of porous ZnO and TiO2 films on the photocatalysis degradation to Rhodamine B solution was investigated. The structure of polystyrene colloidal crystal templates, porous ZnO and TiO2 films was analyzed by scanning electron microscopy. The photocatalysis degradation ability of porous ZnO and TiO2 films was evaluated by ultraviolet-visible spectrometry. The results show that the colloidal crystal prepared by 0.025% polystyrene suspension presents both monolayer and multilayer structure, and as the concentration increases to 0.100%, the colloidal crystal shows perfect multilayer structure. The porous ZnO films obtained from 0.3 mol/L sol and 0.100% polystyrene suspension show better photocatalytic degradation ability. Meanwhile, for the porous TiO2 films, the optimal photocatalytic degradation ability is obtained with 0.1 mol/L sol and 0.025% polystyrene suspension.Whereas, the photocatalytic degradation ability of porous ZnO films is superior to TiO2 films.

  6. Preparation of highly permeable BPPO microfiltration membrane with binary porous structures on a colloidal crystal substrate by the breath figure method.

    Science.gov (United States)

    Yuan, Hua; Yu, Bing; Cong, Hailin; Peng, Qiaohong; Yang, Zhen; Luo, Yongli; Chi, Ming

    2016-01-01

    A highly permeable brominated poly(phenylene oxide) (BPPO) microfiltration membrane with binary porous structures was fabricated by combination of the breath figure and colloidal crystal template methods. The pore size in the bottom layer of the membrane was adjusted by the diameter of SiO2 microspheres in the colloidal crystal template, while the pore size in the top layer of the membrane was adjusted by varying the BPPO concentration in the casting solution. The permeability of the membrane cast on the colloidal crystal substrate was much higher than that of the membrane cast on a bare silicon wafer. The binary porous BPPO membrane with high permeability and antifouling property was used for microfiltration applications.

  7. PREPARATION OF ULTRA-LOW VOLUME WEIGHT AUTOCLAVED AERATED CONCRETE

    Directory of Open Access Journals (Sweden)

    Ondrej Koutny

    2016-12-01

    Full Text Available Autoclaved aerated concrete is a modern construction material that gains its popularity especially due to its thermal insulation performance resulting from low volume weight and porous structure with sufficient mechanical strength. Nowadays, there are attempts to use this material for thermal insulation purposes and to replace current systems, which have many disadvantages, mainly concerning durability. The key for improvement of thermal insulation properties is therefore obtaining a material based on autoclaved aerated concrete with extremely low volume weight (below 200 kg/m ³ ensuring good thermal isolation properties, but with sufficient mechanical properties to allow easy manipulation. This material can be prepared by foaming very fine powder materials such as silica fume or very finely ground sand. This paper deals with the possibilities of preparation and summarizes the basic requirements for successful preparation of such a material.

  8. Preparation of porous bioceramics using reverse thermo-responsive hydrogels in combination with rhBMP-2 carriers: in vitro and in vivo evaluation.

    Science.gov (United States)

    Fu, Yin-Chih; Chen, Chung-Hwan; Wang, Chau-Zen; Wang, Yan-Hsiung; Chang, Je-Ken; Wang, Gwo-Jaw; Ho, Mei-Ling; Wang, Chih-Kuang

    2013-11-01

    Porous biphasic calcium phosphates (BCP) were fabricated using reverse thermo-responsive hydrogels with hydroxyapatite (HAp) and β-tricalcium (β-TCP) powder and planetary centrifugal mixer. This hydrogel mixture slurry will shrink and compress the HAp powder during the sintering process. The porous bioceramics are expected to have good mechanical properties after sintering at 1200°C. Reverse thermo-responsive hydrogels of poly[(N-isopropylacrylamide)-co-(methacrylic acid)] p(NiPAAm-MAA) were synthesized by free-radical cross-linking copolymerization, and their chemical properties were evaluated by nuclear magnetic resonance spectroscopy, infrared spectroscopy, and electrospray-ionization mass spectrometry. The lower critical solution temperature (LCST) of the hydrogel was determined using turbidity measurements. A thermogravimetric analysis was used to examine the thermal properties. The porous bioceramic properties were analyzed by X-ray diffraction, scanning electron microscopy, bulk density, compressive strength testing and cytotoxicity. The compressive strength and average porosity of the porous bioceramics were examined at approximately 6.8MPa and 66% under 10wt% p(NiPAAm-MAA)=99:1 condition. The ratio of HAp/β-TCP can adjust two different compositional behaviors during the 1200°C sintering process without resulting in cell toxicity. The (rhBMP-2)-HAp-PLGA carriers were fabricated as in our previous study of the double emulsion and drop-coating technique. Results of animal study included histological micrographs of the 1-mm defect in the femurs, with the rhBMP-2 carrier group, the bioceramic spacer group and the bioceramic spacer with rhBMP-2 carriers group showing better callus formation around the femur defect site than the control group. The optimal dual effects of the bone growth factors from osteoconductive bioceramics and osteoinductive rhBMP-2 carriers produced better bone formation.

  9. 粉煤灰基多孔陶瓷过滤材料的制备和性能%Preparation and performance of fly ash porous ceramics for filtration

    Institute of Scientific and Technical Information of China (English)

    熊林; 刘晓荣

    2011-01-01

    以粉煤灰为骨料,采用添加造孔剂法制备粉煤灰基多孔陶瓷过滤材料,研究了造孔剂用量和烧结温度对其性能的影响.通过压汞仪、X射线衍射仪和场发射扫描电子显微镜等分析测试技术对试样进行了性能表征.结果表明:随着造孔剂用量的增加,显气孔率和吸水率升高,抗弯强度和密度下降.提高烧结温度可以有效提高抗弯强度,而不影响材料的主要物相组成;当烧结温度大于1 175℃时,显气孔率和透气度显著下降.造孔剂用量为35%,烧结温度为1175℃时,可制得抗弯强度大、气孔发达及高比表面积的多孔陶瓷过滤材料.%Porous ceramics were prepared from fly ash by adding a pore-making agent. Some effects of the amount of the poremaking agent and sintering temperature on the properties of the porous ceramics were studied. The properties of specimens were characterized by pressure mercury analyzer, X-ray diffraction (XRD), and field emission scanning electron microscopy (SEM). The results show that with the pore-making agent increasing, the porosity and water absorption increase, but the bending strength and density decrease. Increasing the sintering temperature can improve the bending strength of the porous ceramics. However, main phases in the porous ceramics are similar at different sintering temperatures. As the sintering temperature is more than 1 175 ℃, the porosity and gas permeability decrease significantly. When the amount of the pore-making agent is 35% and the sintering temperature is 1 175 ℃ , the fly ash porous ceramics for filtration have high bending strength, advanced porosity and high specific surface area.

  10. 光致变色多孔聚苯乙烯功能微球的制备和性能%Preparation of functionalized porous photochromic polystyrene microspheres and their performance

    Institute of Scientific and Technical Information of China (English)

    孙静; 裴广玲

    2011-01-01

    Porous cross-linked polystyrene microspheres were prepared by disperse polymerization in the presence of toluene/heptane as pore-forming agents.The effects of monomer, initiating agent, stabilizer, and cross-linker on the average size of the microspheres were investigated, and the photochromic performance of the porous polystyrene microspheres after adsorbing photochromic materials at ambient temperature and pressure was primarily evaluated.Results indicate that the porous polystyrene microspheres obtained under the optimized conditions have an average grain size of 1 μm.After adsorbing photochromic materials, the porous microspheres were able to rapidly reverse color under ultraviolet or sun light irradiation.Besides, the porous photochromic polystyrene microspheres could be fabricated into photochromic materials by using blending or coating technology; and it was feasible to improve their long lasting discoloring performance by surface-capping.%以甲苯/庚烷为致孔剂,利用分散聚合技术制备了多孔交联聚苯乙烯微球.研究了聚合单体、引发剂、稳定剂、交联剂等对微球平均粒径的影响,并初步评价了其在常温常压下吸附光致变色材料后的光致变色性能.结果表明,在最佳条件下制得的多孔聚合物微球平均粒径为1 μm;吸附光致变色材料后,其在紫外或日光照射下具有快速可逆的光致变色功能.利用共混或涂层技术可以将光致变色微球制备成光致变色材料;通过对变色微球进行表面包覆,可进一步提高其变色持久性.

  11. A fibrous hypercrosslinked sorbent prepared on PP-ST-DVB matrix via post-crosslinking reaction

    Institute of Scientific and Technical Information of China (English)

    Feng Liu; Si Guo Yuan; Xiao Li Wang; A.P. Polikarpov; A.A. Shunkevich

    2007-01-01

    A fibrous sorbent possessing abundant micropore structure was firstly prepared via post-crosslinking reaction on the PP-ST-DVB original fiber. Its micromorphology and sorptive properties were investigated, and the results. Demonstrated that the novel fibrous hypercrosslinked sorbent has narrow pore-size distribution, small average porous radius (1.90 nm), high specific surface area (362.31 m2/g), and fine sorptive properties for small organic molecules.

  12. Research progress in preparation and modification of porous polymeric microspheres for pulmonary drug delivery%肺部给药用高分子多孔微球的制备及改性研究进展

    Institute of Scientific and Technical Information of China (English)

    朱利会; 陈爱政; 王士斌

    2014-01-01

    As a non-invasive administration method,pulmonary drug delivery displays a great potential in the inhalable delivery of protein and peptide. The porous polymeric microspheres are one of the most suitable carriers for pulmonary drug delivery,this article presents several traditional methods to prepare porous polymeric microspheres,and analyzes the pros and cons of these methods under different conditions in the first place. Then,aiming at those questions such as difficulty to achieve a controllable process,and low efficiency in encapsulating drugs,this article reviews the physical and chemical modification of the porous microspheres to obtain a higher performance by the researchers in recent years,and the advices for the existing problems are also proposed. Finally,the combination of different methods to prepare porous polymeric microspheres for pulmonary drug delivery and their potential applications in the field of biomedicine are prospected.%肺部给药作为一种非入侵式的给药方式,在蛋白质、多肽类药物的给药研究中具有很大的发展潜力。高分子多孔微球是最适合肺部给药的药物载体之一,本文首先阐述了高分子多孔微球的几种传统制备方法,分析了这些制备方法在不同的条件下存在的优点及缺点。随后本文针对传统的高分子多孔微球制备条件难以单独控制,药物不能有效包封等问题,对近年来研究者们为了提高多孔微球的性能对其进行的物理化学改性进行了综述并提出了观点。最后对肺部给药用高分子多孔微球不同的制备方法的相互结合以及在生物医学领域的应用价值进行了展望。

  13. 三维打印结合反应烧结制备多孔氮化硅陶瓷%Porous Silicon Nitride Ceramics Prepared by 3D Printing and Reaction Sintering

    Institute of Scientific and Technical Information of China (English)

    翁作海; 曾庆丰; 谢聪伟; 彭军辉; 张瑾

    2013-01-01

    Using silicon powder as starting material and dextrin as binder, porous silicon green body was prepared via 3D printing technology, and then highly porous silicon nitride ceramic was obtained by reaction sintering. The influence of sintering process on the property of the 3DP porous Si3N4 was investigated. The results show that, when the silicon green body was prepared by the 3D printer followed by the step-by-step heating process, porous Si3N4 ceramic with flexural strength of (5. 1 + 0. 3) MPa and porosity of (74. 3 + 0. 6) % was obtained. After reaction sintering, the linear shrinkages of the samples were smaller than 2. 0%. Ceramic parts with complex shapes can be ma-nufactured by such hybrid 3DP and reaction sintering technology with free-form and near-net-shape features.%以硅粉(Si)为起始原料,糊精为粘结剂,采用三维打印(3DP)快速成型技术制备出多孔硅坯体,通过反应烧结得到高孔隙率的氮化硅(Si3N4)陶瓷.研究了反应烧结工艺对3DP多孔Si3N4陶瓷性能的影响.结果表明:3DP成型的硅坯体采用阶梯式升温机制,可得到抗弯强度为(5.1±0.3)MPa,孔隙率达(74.3±0.6)%的多孔Si3 N4陶瓷.反应烧结后,样品的线收缩率小于2.O%.三维打印结合反应烧结法实现了复杂形状陶瓷构件的无模制造与净尺寸成型.

  14. Porous carbons

    Indian Academy of Sciences (India)

    Satish M Manocha

    2003-02-01

    Carbon in dense as well as porous solid form is used in a variety of applications. Activated porous carbons are made through pyrolysis and activation of carbonaceous natural as well as synthetic precursors. Pyrolysed woods replicate the structure of original wood but as such possess very low surface areas and poor adsorption capacities. On activation, these exhibit increased adsorption volumes of 0.5–0.8 cm3 /gm and surface areas of 700–1800 m2 /gm depending on activation conditions, whether physical or chemical. Former carbons possess mixed pore size distribution while chemically activated carbons predominantly possess micropores. Thus, these carbons can be used for adsorption of wide distributions of molecules from gas to liquid. The molecular adsorption within the pores is due to single layer or multilayer molecule deposition at the pore walls and hence results in different types of adsorption isotherm. On the other hand, activated carbon fibres with controlled microporous structure and surface area in the range of 2500 m2 /gm can be developed by controlled pyrolysis and physical activation of amorphous carbon fibres. Active carbon fibres with unmatchable pore structure and surface characteristics are present and futuristic porous materials for a number of applications from pollution control to energy storage.

  15. Preparation of Carbon Nano-fiber Washcoat on Porous Silica Foam as Structured Catalyst Support%大孔二氧化硅膜上纳米碳纤维层结构化催化剂载体的制备

    Institute of Scientific and Technical Information of China (English)

    刘平乐; L.Lefferts

    2006-01-01

    This paper reports how a hairy layer of carbon nano-fibers can be prepared on the macro-porous silica foam produced by the sphere templating method. Firstly, three-dimensional close-packed crystals of polystyrene spheres are assembled on porous disk substrate by vacuum filtration or evaporation. The polystyrene template isannealed slightly above the glass transition temperature in order to strengthen the colloidal crystal and ensure interconnection of the spheres so as to obtain porous materials with open structure. Following the treatment of hexdecyltrimethylammonium bromide, the polystyrene template is filled with silica colloidal solution, which solidifies in the cavities. Then the polystyrene particles are removed by calcination at 843K, leaving behind porous silica foam.Scanning electron microscopy images demonstrate that silica foam has uniform and open structured pores. Nickel particles were deposited on porous silica foam layer by the dipping method and porous carbon nano-fiber washcoat was prepared by catalytic decomposition of ethene over small nickel particles.

  16. Research Progress on Preparation and Surface Activation of Porous Biomedical Metal Materials%医用多孔金属的制备及其生物活化研究进展

    Institute of Scientific and Technical Information of China (English)

    刘辉; 憨勇

    2012-01-01

    Biomedical porous metal materials, especially the porous titanium and titanium alloys, can provide the mechanical properties similar to human bone and promote growth of bone tissue into pores of the materials to enhance the fixation between their implants and bone at early periods of implantation, exhibiting a great potential for the application of human hard tissue repair and replacement. This paper focuses on the preparation methods and research progress of porous titanium and titanium alloys and their surface bio-activation technologies which are suitable for the complex pore structure. Nowadays, the main methods suitable for preparing porous titanium and titanium alloys include powder metallurgy (PM) , titanimn fibers sintering, self-propagating high-temperature synthesis (SHS), selective electron beam mehing (SEBM) and selective laser mehing ( SLM). Surface bio-activation technologies suitable for porous titanium and titanium alloys, including sol-gel processing, bionic solution, electrochemical deposition, and micro-arc oxidation, are also reviewed. As biomedical materials, both mechanical compatibility and surface bioactivity of porous titanium and titanium alloys must be achieved to meet clinical criteria.%医用多孔金属材料,特别是多孔钛及钛合金能够提供与人体骨组织相匹配的力学性能,并促进骨组织长人以提高其与骨的固定度,在人体硬组织修复与替换方面具有广泛的应用前景。重点围绕多孔钛及钛合金的制备方法及适用于其复杂孔隙结构的表面生物活化方法,综述了各种方法在多孔钛及钛合金上的应用现状。目前适用于多孔钛及钛合金制备的技术主要有粉末冶金法、钛纤维烧结法、自蔓延高温合成法、选区电子束熔化技术和选区激光熔化技术,适用于多孔钛及钛合金表面生物活化的技术主要有溶胶凝胶法、仿生矿化法、电化学沉积法和微

  17. Light Emitting Porous Silicon

    Science.gov (United States)

    1993-05-01

    ml - mm m lm m ~ m m ThO report Page 14 preparation method which has been originally described by Wohler [23] leads to a bright yellow substance with...Solid State Commun. 81, 307 (1992). [221 H. Kautsky, and H. Zocher, Z. Phys. 9,267 (1992). L TNO report Page 28 [231 F. Wohler , Lieb. Ann. 127, 275 (1863...Netherlands Fax + 31 70 328 09 61 Phone + 31 70 326 42 21 TNO- report copy no. e FEL-93eo047r Lh Emitting Porous Silicon sitho(s): DTICHMi.P.Th

  18. Porous Thermoelectric Materials

    Directory of Open Access Journals (Sweden)

    Hiroshi Julian Goldsmid

    2009-08-01

    Full Text Available Thermoelectric materials are sometimes prepared using a sintering process in which the achievement of a high density is often one of the objectives. However, it has recently been shown that the introduction of a highly porous material is desirable in synthetic transverse thermoelements. Porosity may also be an advantage in conventional longitudinal thermoelectric modules in which a high thermal flux density creates problems, but heat transfer within the pores can degrade the thermoelectric figure of merit. The amount of this degradation is calculated and it is shown that it can be small enough to be acceptable in practical devices.

  19. Small, porous polyacrylate beads

    Science.gov (United States)

    Rembaum, Alan (Inventor); Yen, Shiao-Ping Siao (Inventor); Dreyer, William J. (Inventor)

    1976-01-01

    Uniformly-shaped, porous, round beads are prepared by the co-polymerization of an acrylic monomer and a cross-linking agent in the presence of 0.05 to 5% by weight of an aqueous soluble polymer such as polyethylene oxide. Cross-linking proceeds at high temperature above about 50.degree.C or at a lower temperature with irradiation. Beads of even shape and even size distribution of less than 2 micron diameter are formed. The beads will find use as adsorbents in chromatography and as markers for studies of cell surface receptors.

  20. Crosslinked, porous, polyacrylate beads

    Science.gov (United States)

    Rembaum, Alan (Inventor); Yen, Shiao-Ping S. (Inventor); Dreyer, William J. (Inventor)

    1977-01-01

    Uniformly-shaped, porous, round beads are prepared by the co-polymerization of an acrylic monomer and a cross-linking agent in the presence of 0.05 to 5% by weight of an aqueous soluble polymer such as polyethylene oxide. Cross-linking proceeds at high temperature above about 50.degree. C or at a lower temperature with irradiation. Beads of even shape and even size distribution of less than 2 micron diameter are formed. The beads will find use as adsorbents in chromatography and as markers for studies of cell surface receptors.

  1. 以尿素为造孔剂制备开孔NiAl金属间化合物%Open-celled porous NiAl intermetallics prepared by replication of carbamide space-holders

    Institute of Scientific and Technical Information of China (English)

    吴杰; 崔洪芝; 曹丽丽; 谷征征

    2011-01-01

    以尿素为造孔剂,利用燃烧合成技术成功制备孔洞结构和力学性能可控可调的开孔NiAl金属间化合物,并对材料的宏观和微观形貌、准静态压缩性能进行分析.通过调整尿素的体积分数和颗粒大小,多孔NiAl金属间化合物的孔隙率可控制在57.57%-84.58%,孔径大小可控制在0.4-2.0 mm.准静态压缩实验表明,多孔NiAl金属间化合物的力学性能可用Gibson-Ashby模型来解释.%Open-celled porous NiAl intermetallics with adjustable pore characteristics and mechanical properties were successfully prepared by using spherical carbamide as space-holders via combustion synthesis.Examinations of macroscopic and microscopic morphologies as well as the quasi-static compressive test for the resultant materials were carried out.Depending on the volume fraction and particle size of the carbamide,the porosity and pore size of the porous NiAl intermetallics can be controlled freely in a range of 57.57%-84.58% and 0.4-2.0 mm,respectively.Furthermore,quasi-static compressive tests indicate that the mechanical behavior of the present porous materials is in good agreement with the Gibson-Ashby model.

  2. Preparation and research on heat preservation performance of porous phase change energy storage granule material%多孔相变储能颗粒的制备及蓄热性能研究

    Institute of Scientific and Technical Information of China (English)

    李书进; 蒋晓曙; 刘燕; 厉见芬

    2012-01-01

    In this article,with lauric -capric acid composite as PCM, expanded perlite, expanded vermiculite and expanded graphite three porous particles as enclosed carrier, three kinds of phase change energy storage granule were prepared by vacuum adsorption and melt impregnation method. Morphology of porous particles before and after the adsorption of PCM was observed through SEM. Phase change temperature and latent heat of energy storage granule were tested by TG-DSC. The results showed that, three kinds of phase change energy storage granule all fall in human comfort temperature range; PCM adsorption quantity and microstructure of porous particle exists direct correlation; after 150 times thermal cycles, phase change temperature and latent heat of phase change energy storage granule were stable.%以月桂酸-癸酸复合二元酸作为PCM,以膨胀珍珠岩、膨胀蛭石和膨胀石墨3种多孔颗粒作为封装载体,用真空吸附-熔融浸渍法制备了3种多孔相变储能颗粒.通过SEM观测多孔颗粒吸附PCM前后的形貌,并用TG-DSC测试多孔相变储能颗粒的相变温度和相变潜热.结果表明,3种多孔相变储能颗粒的相变温度均在人体舒适度范围内;多孔颗粒的微观结构与PCM吸附量存在直接关系;经受150次冷热循环后,多孔相变储能颗粒的相变温度和相变潜热均比较稳定.

  3. Effect of Y2O3 addition on the properties of mullite bonded porous SiC ceramics prepared by an infiltration technique

    Directory of Open Access Journals (Sweden)

    Kayal, N.

    2013-10-01

    Full Text Available Mullite bonded porous SiC ceramics were synthesized by infiltrating a powder compact of SiC and Y2O3 with a liquid precursor of mullite which on subsequent heat treatment at 1300-1500 ºC produced mullite bonded porous SiC ceramics. The effect of Y2O3 content and sintering temperature on phase composition, microstructure, oxidation degree of SiC, flexural strength, porosity and pore size distribution were studied. Due to enhance oxidation and well developed neck formation by the addition of Y2O3 a high strength 49 MPa was achieved for the porous mullite bonded SiC ceramics with porosity 28 vol %.Se han sintetizado materiales porosos de SiC-Mullita mediante la infiltración de polvo prensado de SiC y Y2O3 con un precursor líquido de mullita, el cual con un tratamiento térmico posterior a 1300-1500 °C da lugar a los materiales porosos de SiC-Mullita. Se estudió el efecto del contenido de Y2O3 y la temperatura de sinterización en la constitución mineralógica, en la microestructura, en el grado de oxidación del SiC, la resistencia a la flexión, la porosidad total y su distribución de tamaño. Debido a la oxidación y a la mejora en la formación de los cuellos por la adición de Y2O3, se alcanzan altos valores de resistencia, 49 MPa, para estos materiales porosos de SiC-Mullita con porosidad 28 % en volumen.

  4. Rigid, non-porous and tunable hybrid p-aminobenzoate/TiO2 materials: Toward a fine structural determination of the immobilized RhCl(Ph3)3 complex

    KAUST Repository

    Espinas, Jeff

    2015-05-01

    By exchange of ligands, Wilkinson complex RhCl(PPh3)3 are immobilized on p-aminobenzoate/TiO2 with different organic loading (6, 11 and 16%). This new hybrid material exhibit a linear correlation between the ligand content of the starting TiO2 and the rhodium loading, showing the accessibility of all surfaces amines fonctions on the non-porous parent materials. 1H, 13C, and 1D, 2D INAQUEDATE refocused and J-resolved 31P solid-state NMR confirm the well-defined structure [(≡TiO)2(n{right tail}2-O2C-C6H4-NH2)RhCl-cis-(PPh3)2]. New immobilized catalysts show interesting activity in cyclohexene hydroformylation.

  5. Improved Mixed Particles Cast Preparation and Characterization of Magnetic Porous Scaffolds for Tissue Engineering%改进混粒共浇法制备磁性多孔组织工程支架及其表征

    Institute of Scientific and Technical Information of China (English)

    刘淑英

    2015-01-01

    Using poly lactic acid solution, NaCl particles and Fe3O4 powder as raw material, the preparation can be used for magnetic porous biological scaffold materials for tissue engineering, and the magnetic properties of materials, was used to analyze the microstructure and XRD diffraction. The results show that, this process can not only the formation of porous structure, but also effectively coated magnetic powder materials, keep the good magnetic properties.%采用聚乳酸溶液、NaCl粒子和Fe3O4粉末为原料,制备了可用于组织工程的磁性多孔生物支架材料,并对材料的磁性能、微观结构和XRD衍射进行了分析。结果表明,该工艺不仅可以形成多孔结构,还能有效包裹磁性粉末材料,保留了良好的磁性能。

  6. Luminescence decay of porous silicon

    Science.gov (United States)

    Chen, X.; Uttamchandani, D.; Sander, D.; O'Donnell, K. P.

    1993-04-01

    The luminescence decay pattern of porous silicon samples prepared by electrochemical etching is characterised experimentally by a non-exponential profile, a strong dependence on temperature and an absence of spectral diffusion. We describe this luminescence as carrier-dopping-assisted recombination. Following the correlation function approach to non-dispersive transport developed by Scher and co-workers [Physics Today 41 (1991) 26], we suggest a simple derivation of analytical functions which accurately describes the anomalous luminescence decay of porous silicon, and show that this model includes exponential and Kohlrausch [Pogg. Ann. Phys. 119 (1863) 352] (stretched-exponential) relaxations as special cases.

  7. Photocatalytic Degradation of Rhodamine B Dye over Novel Porous TiO2-SnO2 Nanocomposites Prepared by Hydrothermal Method

    Directory of Open Access Journals (Sweden)

    Yan Wang

    2014-01-01

    Full Text Available The photocatalytic degradation of Rhodamine B dye was successfully carried out under UV irradiation over porous TiO2-SnO2 nanocomposites with various molar ratios of Ti/Sn (4–12 synthesized by hydrothermal method using polystyrene microspheres as template. The combination of TiO2 with SnO2 can obtain high quantum yield of TiO2, and then achieve the high photocatalytic activity. And its porous structure can provide large surface area, leading to more adsorption and fast transfer of dye pollutant. Structural and textural features of the samples were investigated by X-ray diffraction (XRD, transmission electron microscopy (TEM, and N2 sorption techniques. Both adsorption and UV irradiation contribute to decolorization of about 100% of Rhodamine B dye over the sample TiSn10 after 30 min of the photocatalytic reaction, while the decomposition of Rhodamine B dye is only 62% over pure titania (Degussa P25.

  8. Porous Ascend

    DEFF Research Database (Denmark)

    Riiber, Jacob; Tamke, Martin; Ramsgaard Thomsen, Mette

    2012-01-01

    The Porous Ascend project investigates how algorithmic and generative approaches allows for the utilization of complex, and by other means inaccessible, ways of devising the schema by which we arrange the parts of an architectural object. It does so by pursuing to physically realize a structure...... of folded elements, based on the concept of applying recursion to the geometry of the non-periodic Penrose tiling. Within this process the project explores questions regarding the making of bespoke digital design tools, digital production, material behaviour and assemblage strategies. The project points...... with an outside and an efficient distribution of specific material behaviour....

  9. Preparation and Characterization of Bacterial Cellulose/Gelatin Composite Porous Scaffold%细菌纤维素/明胶复合多孔支架材料的制备与表征

    Institute of Scientific and Technical Information of China (English)

    蔡志江; 侯成伟

    2012-01-01

    In this research,a bacterial cellulos(BC)/gelatin composite porous scaffold has been successfully prepared by using BC gel and gelatin solution as raw materials.Characteristics of this BC/gelatin composite porous scaffold are investigated by Fourier transform infrared spectrum(FT-IR),scanning electron microscopy(SEM),X-ray diffraction(XRD) and the tensile test.The results show that the composite scaffold has very well interconnected porous network structure and large aspect surface.Gelatin molecules are not only coated on the BC fibrils surface but also penetrate inside BC.With the introduction of gelatin,the crystal structure of BC becomes less regular,crystallinity and tensile properties tend to decrease,which might be associated with strong interaction between BC and gelatin.The cells incubated in BC/gelatin composite porous scaffold for 48 h are capable of forming cell adhesion and proliferation.It shows much better biocompatibility than pure BC.Therefore,this BC/gelatin scaffold is more suitable for biomedical applications.%介绍了以细菌纤维素水凝胶膜和明胶为原料制备细菌纤维素/明胶多孔复合支架的方法,并利用红外光谱、扫描电子显微镜、X射线衍射及力学性能测试对多孔复合支架进行研究。结果表明,复合多孔支架的表面孔径变大、孔隙率下降,但依然呈三维网络结构;明胶的加入使细菌纤维素的链规整度下降,结晶度变小、力学性能下降;同时,明胶能够调节细胞的响应并且促进细胞的贴附和生长,使细菌纤维素/明胶复合多孔支架更有利于细胞的粘附、增殖,更适用于生物医学领域。

  10. Monolithic porous carbon prepared by Na2CO3 templating as a substrate for a nickel hydroxide electrode%以Na2CO3为模板制备多孔炭片作为Ni(OH)2电极基体

    Institute of Scientific and Technical Information of China (English)

    陈冬; 程杰; 文越华; 潘军青; 杨裕生

    2013-01-01

    Monolithic porous carbon (MPC) was synthesized by a templating method using Na2CO3 as template, novolac-type phenolic resin as carbon precursor and hexamethylenetetramine as hardening agent. The template, carbon precursor and hardening a-gent were mechanically mixed in a grinding machine, hardened at 150 ℃, crushed into fine particles, compacted into a disc, carbonized at 800 ℃ and finally washed with deionized water to form MPC. MPC-Ni(OH)2 electrodes were prepared by loading Ni (OH)2 into the MPC by cathodic deposition. The MPC is hierarchically porous, has an electric conductivity of 20.40 S·cm-1 and a specific surface area of 576 m2· g-1. Charge-discharge characterization of the MPC-Ni ( OH) 2 electrodes shows that the specific capacities based on active material and the whole electrode are 230 mAh·g-1 and 131 mAh·g-1, respectively. This suggests that the MPC is a promising lightweight matrix to host nickel hydroxide to achieve a high specific energy in nickel-based alkaline batteries.%以Na2CO3为模板、线性酚醛树脂为碳源,经粉末压制成型、炭化、除去模板制备MPC.制备的MPC电导率为20.4 S·cm-1,比表面积约576 m2·g-1,具有无序的分级孔结构.将所制MPC作为Ni(OH)2电极基体,以电化学浸渍的方式填充Ni(OH)2,得到MPC-Ni (OH)2电极,测得Ni(OH)2比容量可达230 mAh·g-1,电极比容量为131 mAh·g-1.研究表明,多孔炭片材料作为一种轻质电极基体,可提高氧化镍电极的性能.

  11. Preparation, characterization and catalytic behavior of hierachically porous CuO/α-Fe2O3/SiO2 composite material for CO and o-DCB oxidation

    Institute of Scientific and Technical Information of China (English)

    Xiaodong Ma; Xi Feng; Xuan He; Hongwen Guo; Lu Lü

    2011-01-01

    Hierachically porous (HP) CuO/α-Fe2O3/SiO2 composite material was fabricated by sol-gel method and multi-hydrothermal processes using HP-SiO2 as support.The resulting material was characterized by N2 adsorption-desorption,X-ray diffraction and scanning electron microscopy.The as-prepared CuO/Fe2O3/HP-SiO2 sample,with α-Fe2O3 and CuO nanocrystals,possessed a co-continuous skeleton,through-macroporous and mesoporous structure.Its catalytic behavior for CO and o-DCB oxidation was investigated.The result showed that CuO/Fe2O3/HP-SiO2 catalyst exhibited high catalytic activity for both CO and o-DCB oxidation,indicating its potential application in combined abatement of CO and chlorinated volatile organic compounds.

  12. Synthesis of Nanoscale Lithium-Ion Battery Cathode Materials Using a Porous Polymer Precursor Method

    KAUST Repository

    Deshazer, H.D.

    2011-01-01

    Fine particles of metal oxides with carefully controlled compositions can be easily prepared by the thermal decomposition of porous polymers, such as cellulose, into which solutions containing salts of the desired cations have been dissolved. This is a simple and versatile method that can be used to produce a wide variety of materials with a range of particle sizes and carefully controlled chemical compositions. Examples of the use of this method to produce fine particles of LiCoO2 and Li(NiMnCo)1/3O2, which are used in the positive electrodes of lithium-ion batteries, are shown. Experiments have demonstrated that materials made using this method can have electrochemical properties comparable to those typically produced by more elaborate procedures. © 2011 The Electrochemical Society.

  13. Study on Preparation of Porous Thermal Insulation Materials by Comprehensive Utilization of Tile Industry Waste%建陶厂废料综合利用制备多孔保温材料研究

    Institute of Scientific and Technical Information of China (English)

    王前; 杜庆洋; 姚奇恒; 李成峰; 刘俊成

    2015-01-01

    利用建陶厂抛光砖废渣、废熟料和废生料为原料,通过添加高岭土、煤粉和发泡剂制备多孔保温材料。研究了高岭土和煤粉的用量、烧成温度对样品气孔率、抗压强度和微观结构的影响。利用阿基米德法测量样品的气孔率,万能试验机测试样品的抗压强度,体视显微镜分析样品的微观结构。结果表明:添加20%高岭土和15%煤粉,在1100℃烧结可制备气孔率为59.70%,抗压强度为4.12 MPa,发泡均匀的多孔保温材料。%The porous thermal insulation materials was prepared using tile ceramic waste, kaolin, pulverized coal and blowing agent as raw materials in the thesis. The inlfuence of addition amount of kaolin, pulverized coal and sintering temperature on porosity, compressive strength and microstructure of sample were studied. The porosity of sample was measured by archimedes law. The compressive strength was tested using universal testing machine and the microstructure was observed with the stereo microscope. The experimental results showed that the porous thermal insulation materials with porosity of 59.70%, compressive strength of 4.12 MPa and uniformity of bubbles was prepared when the addition amount of kaolin and pulverized coal was 20% and 15%, and the sintering temperature was 1100℃.

  14. Morphology and transmittance of porous alumina on glass substrate

    Energy Technology Data Exchange (ETDEWEB)

    Guo Peitao, E-mail: guopeitao@hotmail.com [Wuhan University of Technology. Wuhan (China); Xia Zhilin [Wuhan University of Technology. Wuhan (China); Key Laboratory of Low Dimensional Materials and Application Technology, Xiangtan University, Ministry of Education, Xiangtan (China); Xue Yiyu [Wuhan University of Technology. Wuhan (China); Huang Caihua [China Three Gorges University, Yichang (China); Zhao Lixin [Wuhan University of Technology. Wuhan (China)

    2011-02-01

    The porous optical film has higher threshold of laser-induced damage than densified films, for the study of mechanism of laser-induced damage of porous optical film with ordered pore structure. Porous anodic alumina (PAA) film with high transmittance on glass substrate has been prepared. Aluminum film was deposited on glass substrate by means of resistance and electron beam heat (EBH) evaporation. Porous alumina was prepared in oxalic acid solution under different anodizing conditions. At normal incidence, the optical transmittance spectrum over 300-1000 nm spectra region was obtained by spectrophotometer. SEM was introduced to analysis the morphology of the porous alumina film. The pore aperture increased with the increase of anodizing voltage, which resulted in a rapid decrease of the pore concentration and the optical thickness of porous alumina film. Damage morphology of porous alumina film is found to be typically defects initiated, and the defect is the pore presented on the film.

  15. Additive manufacturing technologies of porous metal implants

    Institute of Scientific and Technical Information of China (English)

    Zhou Linxi; Yang Quanzhan; Zhang Guirong; Zhao Fangxin; Shen Gang; Yu Bo

    2014-01-01

    Biomedical metal materials with good corrosion resistance and mechanical properties are widely used in orthopedic surgery and dental implant materials, but they can easily cause stress shielding due to the signiifcant difference in elastic modulus between the implant and human bones. The elastic modulus of porous metals is lower than that of dense metals. Therefore, it is possible to adjust the pore parameters to make the elastic modulus of porous metals match or be comparable with that of the bone tissue. At the same time, the open porous metals with pores connected to each other could provide the structural condition for bone ingrowth, which is helpful in strengthening the biological combination of bone tissue with the implants. Therefore, the preparation technologies of porous metal implants and related research have been drawing more and more attention due to the excellent features of porous metals. Selective laser melting (SLM) and electron beam melting technology (EBM) are important research fields of additive manufacturing. They have the advantages of directly forming arbitrarily complex shaped metal parts which are suitable for the preparation of porous metal implants with complex shape and ifne structure. As new manufacturing technologies, the applications of SLM and EBM for porous metal implants have just begun. This paper aims to understand the technology status of SLM and EBM, the research progress of porous metal implants preparation by using SLM and EBM, and the biological compatibility of the materials, individual design and manufacturing requirements. The existing problems and future research directions for porous metal implants prepared by SLM and EBM methods are discussed in the last paragraph.

  16. Porous microsphere and its applications

    Directory of Open Access Journals (Sweden)

    Cai Y

    2013-03-01

    Full Text Available Yunpeng Cai,1,2* Yinghui Chen,3* Xiaoyun Hong,2 Zhenguo Liu,1 Weien Yuan2 1Department of Neurology, Xinhua Hospital affiliated to Shanghai Jiaotong University School of Medicine, 2School of Pharmacy, Shanghai JiaoTong University, 3Department of Neurology Jinshan Hospital, Fudan University, Shanghai, People's Republic of China *These authors contributed equally to this workAbstract: Porous microspheres have drawn great attention in the last two decades for their potential applications in many fields, such as carriers for drugs, absorption and desorption of substances, pulmonary drug delivery, and tissue regeneration. The application of porous microspheres has become a feasible way to address existing problems. In this essay, we give a brief introduction of the porous microsphere, its characteristics, preparation methods, applications, and a brief summary of existing problems and research tendencies.Keywords: pore, porosity, porogen, suspension polymerization, seed swelling, pulmonary drug delivery, tissue regeneration

  17. Porous pavement. Phase 1: Design and operational criteria

    Science.gov (United States)

    Diniz, E. V.

    1980-08-01

    Utilization concepts, benefits and disadvantages, as well as other characteristics of porous pavements are presented with emphasis on porous asphalt pavements, but the criteria and design approach are applicable to all other porous pavement types. Design considerations include siting problems, load bearing design and hydrologic design. The history of porous pavement development and previous experience with porous pavement by several designers, contractors and operators are described. A computer model for hydrologic performance evaluation of existing or proposed porous pavement systems is also examined. Load bearing design criteria are based on previous work conducted for porous asphalt pavements. Appendices include a sample set of specifications for porous asphalt construction and a list of soils and their permeability classes as prepared by the U.S. Soil Conservation Service.

  18. Improvement of Method to Prepare Porous Anodic Alumina Template%多孔阳极氧化铝(PAA)模板制备方法的改进

    Institute of Scientific and Technical Information of China (English)

    高明

    2016-01-01

    通过改进制备方法成功制备出高度有序的多孔阳极氧化铝(porous anodic alumina,P从)模板.对称结构的电解池两侧容室使用等量的、相同浓度的稀硫酸电解液,能够同时对两片铝片接触电解液的面进行阳极氧化,更好的平衡了铝片两侧的压力,有利于提高所制备模板的有序度,同时提高了制备效率.

  19. γ-ray Irradiation Assisted Preparation of Porous Starch%γ射线辐照辅助制备多孔淀粉

    Institute of Scientific and Technical Information of China (English)

    华成武; 遆永周; 吕晓华; 邓刚; 王晓慧

    2015-01-01

    In this paper,we useα-amylase and glucoamylase to hydrolyze the maize starch byγ-ray irradiation as raw materials in acidic environment less than the pasting temperature. The effects of reaction time ,irradiation dose and other factors on the rates of starch hydrolysis and oil-absorption were studied,and the product forms were also observed with electron microscope. The results show that the electron microscopic morphology and the rates of porous starch hydrolysis and oil-absorption are anastomose essentially,γ-ray irradiation can effectively improve the efficiency of enzymatic hydrolysis of starch,and can greatly improve the oil-absorption rate of porous starch.%以玉米淀粉为原料,以不同剂量γ射线辐照,然后用α-淀粉酶和糖化酶在酸性环境中、糊化温度以下酶解制备多孔淀粉. 探讨了反应时间、辐照剂量等因素对淀粉水解率和吸油率的影响,同时也用电镜观察了产物的形态. 结果表明,电镜下多孔淀粉形态与其水解率和吸油率相吻合,γ射线辐照能有效提高淀粉的酶解效率,可以大幅度提高多孔淀粉的吸油率.

  20. 气体静压轴承用多孔SiC陶瓷的制备及静态性能%Preparation and Static Properties of Porous SiC Ceramic as Aerostatic Bearing

    Institute of Scientific and Technical Information of China (English)

    于雪梅

    2011-01-01

    以α-SiC和β-SiC粉末为原料,羧甲基纤维素为造孔剂,制备了多孔SiC陶瓷.探讨了烧结温度、成型压力和造孔剂含量对SiC陶瓷的气孔率、显气孔率以及弯曲强度的影响,研究了用不同渗透率的多孔SiC陶瓷制备气体静压轴承的承载能力和静态刚度.结果表明:在高温下,β-SiC转变为α-SiC,同时,通过α-SiC的蒸发-凝聚过程实现了SiC陶瓷的烧结,并形成无收缩自结合结构;试样的气孔率和显气孔率随烧结温度和成型压力的增加而略有降低,但弯曲强度却增大;造孔剂含量越高,试样的气孔率和显气孔率越大,弯曲强度越低.添加质量分数为10%的造孔剂,经250 MPa冷等静压成型,在2 400℃下制备的试样气孔率和显气孔率分别为28.91%和24.03%,渗透率为7.74×10-13 m2,弯曲强度为63.8 MPa.因此,多孔siC陶瓷的渗透率越低,利用它制备的气体静压轴承的承载能力越低,静态刚度就越高.%Porous SiC ceramics were prepared with α-SiC and β-SiC powders, and carboxymethyl cellulose(CMC) as the pore entraining agent. The porosity, open porosity, and the flexural strength as functions of sintering temperatures, shaping pressures, and pore entraining agent content were investigated. The load capacity and the static stiffness of aerostatic bearing assembled by porous SiC ceramics with different permeability were studied. The results show that porous SiC ceramic is able to be prepared when the β-SiC converts to α-SiC by the aggregates connection in high temperature range. The porosity and the open porosity decrease and the flexural strength increases with increasing sintering temperatures and shaping pressures. The porosity and the open porosity increases and the flexural strength decreases with increase of pore entraining agent content. For the sample with 10% (mass fraction) CMC prepared at 250 MPa and 2 400 ℃, the porosity and open porosity get respectively 28.91% and 24.03%, the

  1. The Manufacturing of High Porosity Iron with an Ultra-Fine Microstructure via Free Pressureless Spark Plasma Sintering

    Directory of Open Access Journals (Sweden)

    Guodong Cui

    2016-06-01

    Full Text Available High porosity (>40 vol % iron specimens with micro- and nanoscale isotropic pores were fabricated by carrying out free pressureless spark plasma sintering (FPSPS of submicron hollow Fe–N powders at 750 °C. Ultra-fine porous microstructures are obtained by imposing high heating rates during the preparation process. This specially designed approach not only avoids the extra procedures of adding and removing space holders during the formation of porous structures, but also triggers the continued phase transitions of the Fe–N system at relatively lower processing temperatures. The compressive strength and energy absorption characteristics of the FPSPS processed specimens are examined here to be correspondingly improved as a result of the refined microstructure.

  2. Porous Hydrogen-Bonded Organic Frameworks

    Directory of Open Access Journals (Sweden)

    Yi-Fei Han

    2017-02-01

    Full Text Available Ordered porous solid-state architectures constructed via non-covalent supramolecular self-assembly have attracted increasing interest due to their unique advantages and potential applications. Porous metal-coordination organic frameworks (MOFs are generated by the assembly of metal coordination centers and organic linkers. Compared to MOFs, porous hydrogen-bonded organic frameworks (HOFs are readily purified and recovered via simple recrystallization. However, due to lacking of sufficiently ability to orientate self-aggregation of building motifs in predictable manners, rational design and preparation of porous HOFs are still challenging. Herein, we summarize recent developments about porous HOFs and attempt to gain deeper insights into the design strategies of basic building motifs.

  3. 我国超细铜粉研究及生产现状%Status-in-art of Preparation and Production of Ultra-fine Copper Powder in China

    Institute of Scientific and Technical Information of China (English)

    黄凌云; 朱国才; 霍慧彬; 池汝安

    2008-01-01

      The status-in-art of preparation and production of ultra-fine copper powder including ball mill, plasma,γ-ray irradiation-hydrothermal crystallization, chemical reduction, electrolysis, ultrasound electrolysis, hydrothermal, micro emulsions and collosol method are summarized. The advance of pre-reduction-complex reduction used by Institute of Nuclear and New Energy Technology, Tsinghua University was introduced, too. Furthermore, the present state of copper powder consumption and production in China were also analyzed. Finally, the development of ultra-fine copper powder is prospected.%  概述了目前超细铜粉制备方法,包括球磨法、等离子体法、γ射线辐照射法、雾化法、超声电解法、电解法、微乳液法、溶胶-凝胶法、化学还原法等的研究现状,介绍了清华大学核能与新能源技术研究院采用的预还原-复合还原法。同时,对我国的铜粉消费与生产现状作了分析,并对我国今后超细铜粉研究作了展望。

  4. A way to inhibit SO[sub 2] poisoning of SCR catalysts by fine tuning of the composition and the preparation method of the support

    Energy Technology Data Exchange (ETDEWEB)

    Matralis, H.; Fiasse, S.; Bastians, Ph.; Ruwet, M.; Grange, P.; Delmon, B. (Unite de Catalyse et Chimie des Materiaux Divise, Louvain-la-Neuve (Belgium)); Castillo, R. (Monomeros Colombo Venezolanos (EMA), Las Flores Barranquilla (Colombia))

    1993-05-26

    Two series of mixed SiO[sub 2]-TiO[sub 2] and Al[sub 2]O[sub 3]-TiO[sub 2] supports were prepared by the following methods: precipitation from TiCl[sub 4] solution with aqueous ammonia, impregnation with titanium isopropoxide solution in isopropanol, and grafting by reaction of TiCl[sub 4] with the hydroxyl groups of the main carrier (SiO[sub 2] or Al[sub 2]O[sub 3]). The vanadia catalysts, resulting from the impregnation of these mixed supports with an aqueous solution of vanadium oxalate, were tested in the selective catalytic reduction-(SCR) of NO with NH[sub 3] in the presence of O[sub 2]. BET, XRD and XPS were used to characterise the samples. All these catalysts were less active than a standard TiO[sub 2]-V[sub 2]O[sub 5] catalyst when tested with a SO[sub 2]-free feed. However, in the presence of 4000 ppm SO[sub 2] in the feed they were more resistant and more active than the TiO[sub 2]-V[sub 2]O[sub 5] catalyst. Our results indicate that the dispersion of TiO[sub 2] on the main carrier is a key factor for preparing a performant SCR-catalyst. The grafting and impregnation methods for the Al[sub 2]O[sub 3]-TiO[sub 2] and the impregnation for the SiO[sub 2]-TiO[sub 2] supports were found to be the most effective preparation techniques for dispersing TiO[sub 2], and for giving the most performant and resistant, towards SO[sub 2] poisoning, catalysts.

  5. 超重力氨法制备超细氧化锌%Preparation of Ultra-Fine Zinc Oxide by Ammonia Decomposition Method in High Gravity Field

    Institute of Scientific and Technical Information of China (English)

    焦纬洲; 刘有智; 祁贵生; 杨森; 李孟委

    2012-01-01

    在旋转填料床反应器中,以锌氨络合物与蒸汽为原料制得氧化锌前驱体,经煅烧后得到超细氧化锌产品.考察了超重力因子、气液比、蒸汽流量和温度等操作参数对产品收率的影响.结果表明,在超重力因子167.2,气液比1.14 kg/L,蒸汽流量 30 L/h和蒸汽温度135℃的条件下,沉锌率较高,可达96.7%.氧化锌产品的透射电镜(TEM)表征结果表明,其形貌为近球状,平均粒径为45 nm.%In the high gravity rotating packed bed reactor, the zinc-ammonia complex solution reacted with steam to precipitate the precursor of zinc oxide, which was then calcinated into ultra-fine zinc oxide. The effects of gravity factor, gas-liquid ratio, steam flow rate and temperature on the efficiency of zinc precipitation were investigated. The results showed that the zinc precipitation could reach up to 96.7% under the conditions of gravity factor of 167.2, gas-liquid ratio of 1.14 kg/L, steam flow rate of 30 L/h and steam temperature of 135℃. Transmission electron microscope (TEM) results showed that the product had a near spherical morphology with an average particle size of 45 nm.

  6. Porous metal oxide microspheres from ion exchange resin

    Science.gov (United States)

    Picart, S.; Parant, P.; Caisso, M.; Remy, E.; Mokhtari, H.; Jobelin, I.; Bayle, J. P.; Martin, C. L.; Blanchart, P.; Ayral, A.; Delahaye, T.

    2015-07-01

    This study is devoted to the synthesis and the characterization of porous metal oxide microsphere from metal loaded ion exchange resin. Their application concerns the fabrication of uranium-americium oxide pellets using the powder-free process called Calcined Resin Microsphere Pelletization (CRMP). Those mixed oxide ceramics are one of the materials envisaged for americium transmutation in sodium fast neutron reactors. The advantage of such microsphere precursor compared to classical oxide powder is the diminution of the risk of fine dissemination which can be critical for the handling of highly radioactive powders such as americium based oxides and the improvement of flowability for the filling of compaction chamber. Those millimetric oxide microspheres incorporating uranium and americium were synthesized and characterizations showed a very porous microstructure very brittle in nature which occurred to be adapted to shaping by compaction. Studies allowed to determine an optimal heat treatment with calcination temperature comprised between 700-800 °C and temperature rate lower than 2 °C/min. Oxide Precursors were die-pressed into pellets and then sintered under air to form regular ceramic pellets of 95% of theoretical density (TD) and of homogeneous microstructure. This study validated thus the scientific feasibility of the CRMP process to prepare bearing americium target in a powder free manner.

  7. Porous Dielectrics in Microelectronic Wiring Applications

    Directory of Open Access Journals (Sweden)

    Vincent McGahay

    2010-01-01

    Full Text Available Porous insulators are utilized in the wiring structure of microelectronic devices as a means of reducing, through low dielectric permittivity, power consumption and signal delay in integrated circuits. They are typically based on low density modifications of amorphous SiO2 known as SiCOH or carbon-doped oxides, in which free volume is created through the removal of labile organic phases. Porous dielectrics pose a number of technological challenges related to chemical and mechanical stability, particularly in regard to semiconductor processing methods. This review discusses porous dielectric film preparation techniques, key issues encountered, and mitigation strategies.

  8. Removal of two ionic dyes from water by MgO-loaded porous carbons prepared through one-step process from poly(ethylene terephthalate)/magnesium carbonate mixtures

    Indian Academy of Sciences (India)

    A Czyżewski; J Karolczyk; A Usarek; J Przepiórski

    2012-04-01

    Mixtures of poly(ethylene terephthalate) and magnesium carbonate at different weight ratios were heated up to 850°C in argon atmosphere. During heating, components of the initial mixtures underwent thermal decomposition yielding porous carbon materials loaded with different amounts of magnesium oxide. Structural characteristics of the prepared materials were determined from adsorption/desorption isotherms of nitrogen, measured at 77 K. For reference, portions of the products obtained were acid-washed to obtain MgO-free carbons. Pore structures of the prepared materials were strongly dependent on the quantitative compositions of starting mixtures. As a rule, specific surface areas determined for acid-washed materials were much higher than those for MgO-loaded carbons. The adsorption abilities of obtained materials towards cationic (Basic Red 18) and anionic (Reactive Red 198) dyes as model contaminants were examined. Surprisingly, in spite of relatively low specific surface areas, substantially high adsorption of the dyes on MgO-loaded carbons was observed. An influence of specific surface area and the role of magnesium oxide presence on the adsorption capacity of the acquired sorbents were studied.

  9. Fast lithium intercalation chemistry of the hierarchically porous Li2FeP2O7/C composite prepared by an iron-reduction method

    Science.gov (United States)

    Tan, L.; Zhang, S.; Deng, C.

    2015-02-01

    Lithium iron pyrophosphate has drawn great attention because of its interesting physical and electrochemical properties, whereas its high rate capability is far from satisfactory. We synthesize nano-Li2FeP2O7/C with hierarchical pore via a low cost method which uses iron powder instead of Vitamin C as the reducing agent. The hierarchical pore is constructed through a "combustion" mechanism according to the thermogravimetric and morphological characterizations. The phase-pure nanoparticles of Li2FeP2O7 are embedded in the three-dimensional network of amorphous carbon. The hierarchical pore together with the two-dimensional diffusion channel of lithium in Li2FeP2O7 is beneficial to lithium diffusion capability which is evaluated by the lithium diffusion coefficients calculated from the results of GITT measurements. The fast lithium intercalation chemistry facilitates the reversible de/intercalation of lithium, resulting in the high cycling stability and rate-capability. After 100 cycles at the current density of 1C, 93.8% of the initial capacity is retained. The discharge capacity is 62.1 mAh g-1 at the current density of 4C. Therefore, the hierarchically porous nano-Li2FeP2O7/C is a promising cathode material for advanced rechargeable lithium ion battery.

  10. Preparation of explosive nanoparticles in a porous chromium(III) oxide matrix: a first attempt to control the reactivity of explosives

    Energy Technology Data Exchange (ETDEWEB)

    Comet, M; Siegert, B; Pichot, V; Gibot, P; Spitzer, D [Laboratoire ISL/CNRS ' Nanomateriaux pour les Systemes Sous Sollicitations Extremes' (NS3E), FRE 3026, French-German Research Institute of Saint-Louis (ISL), 5 rue du General Cassagnou, 68301 Saint-Louis (France)], E-mail: comet@isl.tm.fr

    2008-07-16

    This paper reports the first attempt to control the combustion and the detonation properties of a high explosive through its structure. A porous chromium(III) oxide matrix produced by the combustion of ammonium dichromate was infiltrated by hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). The structure of the Cr{sub 2}O{sub 3} matrix was studied by both scanning and transmission electron microscopy (SEM, TEM); the Cr{sub 2}O{sub 3}/RDX nanocomposites were characterized by nitrogen adsorption. A mathematical model based on these techniques was used to demonstrate that the Cr{sub 2}O{sub 3} matrix encloses and stabilizes RDX particles at the nanoscale. The decomposition process of the nanocomposites was investigated by atomic force microscopy (AFM). The reactivity and sensitivity of the nanocomposites were studied by impact and friction tests, differential scanning calorimetry (DSC), time-resolved cinematography and detonation experiments, and were correlated with their structure. The size of RDX nanoparticles and their distribution in the Cr{sub 2}O{sub 3} matrix have an important influence on their reactivity. The reactive properties of nanostructured RDX differ significantly from those of classical micron-sized RDX. For instance, the melting point disappears and the decomposition temperature is significantly lowered. The quantization of the explosive particles in the Cr{sub 2}O{sub 3} matrix decreases the sensitivity to mechanical stress and allows controlling the decomposition mode-i.e. combustion versus detonation.

  11. Preparation of explosive nanoparticles in a porous chromium(III) oxide matrix: a first attempt to control the reactivity of explosives

    Science.gov (United States)

    Comet, M.; Siegert, B.; Pichot, V.; Gibot, P.; Spitzer, D.

    2008-07-01

    This paper reports the first attempt to control the combustion and the detonation properties of a high explosive through its structure. A porous chromium(III) oxide matrix produced by the combustion of ammonium dichromate was infiltrated by hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). The structure of the Cr2O3 matrix was studied by both scanning and transmission electron microscopy (SEM, TEM); the Cr2O3/RDX nanocomposites were characterized by nitrogen adsorption. A mathematical model based on these techniques was used to demonstrate that the Cr2O3 matrix encloses and stabilizes RDX particles at the nanoscale. The decomposition process of the nanocomposites was investigated by atomic force microscopy (AFM). The reactivity and sensitivity of the nanocomposites were studied by impact and friction tests, differential scanning calorimetry (DSC), time-resolved cinematography and detonation experiments, and were correlated with their structure. The size of RDX nanoparticles and their distribution in the Cr2O3 matrix have an important influence on their reactivity. The reactive properties of nanostructured RDX differ significantly from those of classical micron-sized RDX. For instance, the melting point disappears and the decomposition temperature is significantly lowered. The quantization of the explosive particles in the Cr2O3 matrix decreases the sensitivity to mechanical stress and allows controlling the decomposition mode—i.e. combustion versus detonation.

  12. Effect of hydrofluoric acid concentration on the evolution of photoluminescence characteristics in porous silicon nanowires prepared by Ag-assisted electroless etching method

    KAUST Repository

    Najar, Adel

    2012-01-01

    We report on the structural and optical properties of porous silicon nanowires (PSiNWs) fabricated using silver (Ag) ions assisted electroless etching method. Silicon nanocrystallites with sizes <5 nm embedded in amorphous silica have been observed from PSiNW samples etched using the optimum hydrofluoric acid (HF) concentration. The strongest photoluminescence (PL) signal has been measured from samples etched with 4.8 M of HF, beyond which a significant decreasing in PL emission intensity has been observed. A qualitative model is proposed for the formation of PSiNWs in the presence of Ag catalyst. This model affirms our observations in PL enhancement for samples etched using HF <4.8 M and the eventual PL reduction for samples etched beyond 4.8 M of HF concentration. The enhancement in PL signals has been associated to the formation of PSiNWs and the quantum confinement effect in the Si nanocrystallites. Compared to PSiNWs without Si-O x, the HF treated samples exhibited significant blue PL peak shift of 100 nm. This effect has been correlated to the formation of defect states in the surface oxide. PSiNWs fabricated using the electroless etching method can find useful applications in optical sensors and as anti-reflection layer in silicon-based solar cells. © 2012 American Institute of Physics.

  13. 木质含碳生物陶粒的制备工艺及性能%Preparation and characterization of wood porous ceramsite

    Institute of Scientific and Technical Information of China (English)

    鲍腾; 陈天虎; 陈冬; 庆承松

    2013-01-01

    以凹凸棒石粘土(Pg)、锯末(成孔剂)和水玻璃(粘结剂)为原料,通氮气保护炭化,制备出符合国家水处理标准的木质含碳生物陶粒(Wood Porous Ceramsite,WPC).利用所制备WPC的抗压强度作为评价WPC质量的指标,通过单因素实验、正交实验来优化WPC的物料配比和煅烧工艺,并通过X射线衍射(XRD)、扫描电子显微镜(SEM),偏光显微镜(polarizing microscope-PM),比表面积(BET)等技术来表征WPC结构特征及其特性.结果表明:WPC具有较大比表面积(75 m2/g)和较高的孔隙率(83%),以开放空隙为主.由于微生物可以深入陶粒内部附着生长,在相同培养条件下挂膜实验结果表明,该复合陶粒生物负载量高于市售陶粒,可望为曝气生物滤池提供新的功能性材料.

  14. Toward Lower Overpotential through Improved Electron Transport Property: Hierarchically Porous CoN Nanorods Prepared by Nitridation for Lithium-Oxygen Batteries.

    Science.gov (United States)

    Xu, Shu-Mao; Zhu, Qian-Cheng; Harris, Michelle; Chen, Tong-Heng; Ma, Chao; Wei, Xiao; Xu, Hua-Sheng; Zhou, Yong-Xian; Cao, Yu-Cai; Wang, Kai-Xue; Chen, Jie-Sheng

    2016-09-14

    To lower the overpotential of a lithium-oxygen battery, electron transport at the solid-to-solid interface between the discharge product Li2O2 and the cathode catalyst is of great significance. Here we propose a strategy to enhance electron transport property of the cathode catalyst by the replace of oxygen atoms in the generally used metal oxide-based catalysts with nitrogen atoms to improve electron density at Fermi energy after nitridation. Hierarchically porous CoN nanorods were obtained by thermal treatment of Co3O4 nanorods under ammonia atmosphere at 350 °C. Compared with that of the pristine Co3O4 precursor before nitridation, the overpotential of the obtained CoN cathode was significantly decreased. Moreover, specific capacity and cycling stability of the CoN nanorods were enhanced. It is assumed that the discharged products with different morphologies for Co3O4 and CoN cathodes might be closely associated with the variation in the electronic density induced by occupancy of nitrogen atoms into interstitial sites of metal lattice after nitridation. The nitridation strategy for improved electron density proposed in this work is proved to be a simple but efficient way to improve the electrochemical performance of metal oxide based cathodes for lithium-oxygen batteries.

  15. GP水沟用多孔混凝土的制备与性能研究%The Study of Preparation and Property on Porous Concrete in GP

    Institute of Scientific and Technical Information of China (English)

    任沙

    2011-01-01

    GP水沟用多孔混凝土是植生混凝土的一种,主要在高速公路排水设施的GP水沟上(Grassed swale based on Porous concrete)使用.该混凝土使用粒径为20~40 mm的断级配、不连续的卵石或碎石,水灰比在0.20~0.40之间.经实验测定,该混凝土在目标空隙率为30%时,制成试块的实测空隙率基本大于30%,抗压强度基本超过10 MPa,符合植生多孔混凝土的主要技术性能要求.该混凝土在不久的将来,有望在高速公路环保绿化工程上得到广泛应用.

  16. 醇-水基料浆凝胶注模成形制备氧化铝多孔陶瓷%Porous alumina ceramics prepared by alcohol-water based gel casting process

    Institute of Scientific and Technical Information of China (English)

    彭俊; 李国栋; 熊翔; 刘靖忠; 霍凌霞

    2014-01-01

    以氧化铝粉为原料,乙醇-水为溶剂,采用凝胶注模成形工艺制备氧化铝多孔陶瓷,并研究溶剂中醇、水体积比对多孔陶瓷坯体和烧结体的收缩率、孔隙度、微观形貌及性能的影响。结果表明:多孔陶瓷的孔隙由溶剂挥发形成的“溶剂孔”和高聚物分解形成的“高聚物孔”两部分组成,孔隙呈三维贯通孔结构。当醇、水体积比由3:7增加至9:1时,制品线收缩率与抗弯强度逐渐减小,孔隙度和气体渗透通量逐渐增加。当醇、水体积比为7:3时,所制备的陶瓷具有优良的综合性能:孔隙率为76.91%,孔隙分布均匀,抗弯强度为13.08 MPa,气体渗透通量达到135.6 m3/(m2·h·kPa)。%Using high purity alumina powder as raw material, alcohol-water mixture as solvent, porous alumina ceramics were fabricated by alcohol-water based gel casting process. The effect of alcohol-water solvent ratio on the shrinking percentage, porosity, microstructure, properties of porous alumina green body and sintered ceramics were investigated. Both evaporation of solvent and decomposition of polymer contribute to the porous microstructure of the as-prepared green body and sintered ceramics, which features three dimensional inter-connected pores. With increasing the alcohol-water ratio from 3:7 to 9:1, the line shrinking percentage and flexural strength decrease, porosity and air permeability increase. When alcohol-water ratio is 7:3, optimal comprehensive performances, including uniformly distributed pores with porosity of 76.91%, flexural strength of 13.08 MPa and air permeability of 135.6 m3/(m2hkPa), can be obtained.

  17. Preparation of Porous Carbon with Waste Corn Cob and its Adsorption of Benzene%玉米芯废渣多孔碳的制备及其对液体苯的吸附

    Institute of Scientific and Technical Information of China (English)

    王倩; 张璇; 段华珍; 冯彤; 余秋兰; 吴志翔; 吴燕

    2016-01-01

    Porous carbon for absorbing liquid hazardous chemicals-benzene was prepared through chemical activation with waste corn cob as the raw material and KOH as the activator.Thermal gravimetric analysis,X-ray diffraction(XRD),and scanning electron microscope(SEM)were used to analyse the microstructure and apparent morphology of the porous car-bon.The results showed that under the conditions of 350,℃carbonization temperature,30,minutes of carbonization time, 4∶1,KOH/C mass ratio,and 120,minutes of activation time,the best activation temperature was 900,℃,the pore-forming effect of KOH was best,the porous carbons products were mainly microporous in structure,the surface area was 2,387,m2/g, and the adsorption capacity was 14,235,mg/g.%以玉米芯废渣为原料、KOH为活化剂,采用化学活化法制备多孔碳材料用于液体危化品苯的吸附.通过热重分析仪、X 射线衍射仪(XRD)、扫描电子显微镜(SEM)分析多孔碳的微观结构和表观形貌.研究表明:在碳化温度350,℃、碳化保温时间30,min、m(KOH)∶m(C)=4∶1、活化保温时间120,min 的条件下,最佳活化温度为900,℃, KOH 的造孔效果最好,制备的多孔碳产品以微孔为主,比表面积达到2,387,m2/g ,对苯的饱和吸附量最大为14,235,mg/g.

  18. 微波掺氮有序多孔TiO2材料的制备与性能%Properties of Ordered Porous N-Doped TiO2 Prepared by Microwave Irradiation

    Institute of Scientific and Technical Information of China (English)

    江学良; 吉钰纯; 周爱军

    2011-01-01

    采用晶胶模板法制备了有序多孔TiO材料,在微波辐照条件下对其掺氮改性,利用扫描电镜(SEM)、X射线衍射(XRD)、光电子能谱(XPS)方法对掺氮TiO材料进行表征,并研究掺氮前后TiO材料光催化性能.实验结果显示,通过晶胶模板法所制备的有序多孔TiO材料的整体比较致密,但局部有孔洞的塌陷.微波辐照前后有序多孔TiO材料的晶型没有改变,依然为锐钛型.XPS分析发现微波辐照后有序多孔TiO材料含有少量的氮元素,表明微波辐照制备掺氮有序多孔TiO材料是成功的.掺氮TiO材料的光催化性能好于未掺氮TiO光催化性能.%Ordered porous TiO2 materials were prepared by the colloidal crystal templating method, and N-doped TiO2 was obtained by microwave irradiation. N-doped TiO2 was characterized by scanning electron microscope (SEM), X-ray diffraction (XRD) and X-ray photoelectron specroscopy (XPS), the photocatalysis properties of N doped TiO2 were studied compared to non-N-doped TiO2. The results indicate that the close-packed porous TiO2 is obtained, but part faulty can be seen. The microwave irradiation doesn't change crystal form of porous TiO2 which is a single anatase. XPS analysis shows that the method of the microwave irradiation is successful since the sample after the microwave irradiation contains a little N element. The photocatalysis property of N-doped TiO2 is better than that of non-N-doped TiO2.

  19. 牛骨原料多孔生物陶瓷的制备及性能表征%PREPARATION AND PROPERTIES OF POROUS BIOCERAMICS MADE OF BOVINE BONE

    Institute of Scientific and Technical Information of China (English)

    丁云飞; 张学斌; 王松林

    2009-01-01

    以煅烧后的牛骨粉体(羟基磷灰石)为原料,以尿素为造孔剂,模压后烧结.制备出多孔生物陶瓷.考察了球磨时间对牛骨粉体粒径的影响,研究了尿素添加量的对多孔陶瓷微结构和力学性能的影响.多孔生物陶瓷的孔隙率约为34%~60%,平均孔径约为110 μm,抗弯强度,压缩强度和弹性模量分别位于40.15MPa~64.72MPa,7.05MPa~10.48MPa,5.98~9.72GPa;微结构和力学性能均能满足人工骨替代材料要求.%The porous hydroxyapatite (HAP) bioceramics was prepared using HAP powder from calcined bovine bone and urea as pore-creating agent. The influence of milling time on the particle size, and the influences of urea content on the micostrcuture and mechanical properties were researched. The average pore size is about 110μm. The porosities distribute from 34%-60%. And the flexural strength, compressive strength and Young's modulus of the porous bioceramics were 40.15MPa~64.72MPa, 7.05MPa~10.48MPa and 5.98~9.72GPa, respectively. All the results can meet the requirements of the human bone substitute.

  20. Self-activated Carex Meyeriana Kunth-based Porous Carbon Prepared by Direct Carbonization and Its Electrochemical Properties%自活化乌拉草基多孔碳的制备和电化学性质

    Institute of Scientific and Technical Information of China (English)

    王昀; 贲腾; 裘式纶

    2016-01-01

    Porous carbon material UlaC-950-HF( Ula stands for Carex meyeriana Kunth, C is short for carbo-nized, 950 is the optimized temperature, and HF is the etchant) was prepared through direct carbonization of Carex meyeriana Kunth after necessary impurity removal. The precursor self-activated in the process of pyroly-sis. The electrochemical measurements of the UlaC-950-HF sample and several other carbonized biomass-based porous carbon materials were carried out. The results revealed that the capacitance of UlaC-950-HF was 113 F/g. In addition, the electrode showed excellent cycling stability as its specific capacitance decreased only by 4 F/g after 4000 voltammetry cycles, showing its potential of being applied in the supercapacitor electrode material.%以乌拉草为原料,采用直接碳化方法,通过热解过程中前驱体自活化(即利用自身包含的活化剂实现分子内的化学活化),并经过必要的除杂过程制备了多孔碳材料UlaC-950-HF.测试了该多孔碳的电化学性质,并与以几种常见的生物质为原料制备的多孔碳材料及商用活性炭的电化学性质进行对比.结果表明,乌拉草基多孔碳材料UlaC-950-HF的电容值为113 F/g,经过4000次循环后,材料的电容值仅降低了4 F/g,显示出用作超级电容器电极材料的潜力.