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61.
Hong-Wen Wang Chien-Hung Kuo Hsiu-Chu Lin I.-Ting Kuo Chi-Feng Cheng 《Journal of the American Ceramic Society》2006,89(11):3388-3392
Rapid formation of active, mesoporous, and crystalline TiO2 photocatalysts via a novel microwave hydrothermal process is presented. Crystalline anatase mesoporous nanopowders 100–300 nm in size with worm hole-like pore sizes of 3–5 nm were prepared by a modified sol–gel of titanium tetra-isopropoxide, accelerated by a microwave hydrothermal process. The organic surfactant, tetradecylamine, which is used as a self-assembly micelle in the sol–gel and microwave hydrothermal process, enables to harvest crystallized mesoporous anatase nanoparticles with a high-surface area. Mesoporous worm hole-like and crystalline powders with surface areas of 243–622 m2 /g are obtained. X-ray diffraction, N2 -adsorption isotherms (Barrett–Joyner–Halenda and Brunauer–Emmet–Teller method), scanning electron microscope, and transmission electron microscope are used to identify the characteristics and morphologies of the powders. It is shown that crystallization by calcination at 400°C/3 h inevitably reduced the surface area, while the microwave hydrothermal process demonstrated a rapid formation of crystalline mesoporous TiO2 nanopowders with a high-surface area and excellent photocatalytic effects. 相似文献
62.
For this study, we first prepared a fluorocarbon polymer and its hybrid materials. We found that fluorocarbon copolymers can produce hydrogen bonds with SiO2 to form hybrid materials. We also used thermogravimetric analyzer and tested the thermostabilities of the four products, which were ranked as follows: fluorocarbon copolymer/SiO2 hybrid material > fluorocarbon polymer/SiO2 hybrid material > fluorocarbon copolymer > fluorocarbon polymer. In addition, we found that, due to the inorganic SiO2 used, the number of pores and the specific surface areas of the hybrid materials both increased. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1140–1145, 2007 相似文献
63.
In Yang Monlin Kuo Deland J. Myers 《Journal of the American Oil Chemists' Society》2006,83(3):239-245
Chromated copper arsenate (CCA), an arsenicbased wood preservative, is toxic to human health and the environment. Although
CCA is stable in seasoned wood, there are potential dangers during CCA manufacture, lumber treatment, and waste disposal.
This research was conducted to study the effectiveness of soy products to replace toxic chromium and arsenic compounds in
wood preservative formulations. Three soy product (Arpro 2100, HM 90, and Supro 760) were used as fixative agents in preservative
solutions containing anhydrous CuSO4 and Na2B4O7·10H2O. The decay resistance of treated wood blocks was measured by a soil-block culture method. Despite the large molecular sizes
of copper-protein and copper-boron-protein complexes, southern pine sapwood was treatable with these preservative formulations.
Wood samples treated with >6 kg°m−3 CuSO4 and 7.5 kg·m−3 soy product, and subsequently leached for 3 d and exposed to the decay fungus Gloeophyllum trabeum (Fr.) Mur., sustained only 0.5% weight loss over 12 wk. Wood samples needed 40 kg·m−3 CuSO4 and 50 kg·m−3 soy protein to resist the copper-tolerant decay fungus Postia placenta (Fr.) M. Lars. & Lomb. These results suggest that soy-based wood preservatives can prevent wood products from fungal attack
and can replace CCA. 相似文献
64.
Multimedia Tools and Applications - Rate distortion optimization technique is adopted by H.264/AVC to select the best intra and inter prediction modes. It achieves remarkable improvement in... 相似文献
65.
Jason Crampton Michael Huth Jim Huan-Pu Kuo 《International Journal on Software Tools for Technology Transfer (STTT)》2014,16(1):31-48
Many business processes are modeled as workflows, which often need to comply with business rules, legal requirements, and authorization policies. Workflow satisfiability is the problem of determining whether there exists a workflow instance that realizes the workflow specification while simultaneously complying with such constraints. This problem has already been studied by the computer security community, with the development of algorithms and the study of their worst-case complexity. These solutions are often tailored to a particular workflow model and are, therefore, of little or no use in analyzing different models; their worst-case complexities are likely to be an unreliable judge of their feasibility; and they lack support for other forms of analysis such as the determination of the smallest number of users required to satisfy a workflow specification. We propose model checking of an NP-complete fragment $\mathsf{LTL }(\mathsf{F })$ of propositional linear-time temporal logic as an alternative solution. We report encodings in LTL(F) that can compute a set of solutions (thus deciding satisfiability), compute minimal user bases and a safe bound on the resiliency of satisfiability under the removal of users. These theoretical contributions are validated through detailed experiments whose results attest to the viability of our proposed approach. 相似文献
66.
The UV‐curable urethane‐acrylates based on 2‐hydroxyethyl methacrylate (HEMA)‐terminated polyurethane (PU) for lithographic and coating applications are investigated in this study. Series of PU prepolymers were made from 4,4‐diphenyl methane diisocyanate (MDI), poly(propylene oxide) glycol (PPG 400), poly(butylene adipate)glycol (PBA 500), or poly(tetramethylene oxide) glycol (PTMO 1000) and are terminated with HEMA. The 2,2‐azobisisobutyronitrile (AIBN) was used as a UV‐initiator under air atmosphere. The curing kinetics of HEMA‐terminated PU film were studied. The curing analysis, using FTIR and reaction kinetics, indicate the reaction rate equation correlates well with the film thickness [T], initiator concentration [I], unreacted double bond concentration [C?C], and exposed energy [E] of the reaction system. The kinetic rate equation for the UV‐curable reaction can be written as © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3162–3166, 2004 相似文献
67.
Wen‐Bin Liau Yu‐Ting Sun Ling‐Yueh Yang Lee‐Yih Wang Wen‐Yen Chiu Kuo‐Huang Hsieh Sheng‐Mao Tseng 《应用聚合物科学杂志》2006,102(6):5406-5413
The polyaniline (PANI)‐coated polystyrene (PS) latexes were synthesized, and the electrically conductive films were prepared thereafter. The weight ratio of PANI was 5%. Thermal analysis of the latices was performed using DSC and TGA. In this study, the electrically conductive films were prepared above the PS glass transition temperature (Tg). During the film formation, the effects of the annealing temperature and atmosphere (air or N2) on the film resistance were investigated. In addition, the film morphology was observed utilizing scanning electron microscopy. The film resistance decreased in the initial heating stage due to the increasing temperature and the compaction of film. Then the film resistance increased with further annealing due to the aging of PANI. Typically, the film resistance was about 6000 Ω/sq, and the conductivity was 0.3 S/cm. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5406–5413, 2006 相似文献
68.
本文从实际使用出发,提出了多媒体教学系统的设计思路,主要介绍了多媒体教学系统的系统结构、主要系统功能等。 相似文献
69.
Free acids of the iron substituted heteropoly acids (HPA), H7[(P2W17O61)FeIII(H2O)] (HFe1) and H18[(P2W15O56)2FeIII2(H2O)2] (HFe2) were prepared from the salts K7[(P2W17O61)FeIII(H2O)] (KFe1) and Na12[(P2W15O56)2FeIII4(H2O)2] (NaFe4), respectively. The iron-substituted HPA were adsorbed on to XC-72 carbon based GDLs to form HPA doped GDEs after water washing with HPA loadings of ca. 1 μmol. The HPA was detected throughout the GDL by EDX. Solution electrochemistry of the free acids are reported for the first time in sulfate buffer, pH 1-3. The hydrogen oxidation reaction was catalyzed by KFe1 at 0.33 V, with an exchange current density of 38 mA/cm2. Moderate activity for the oxygen reduction reaction was observed for the iron substituted HPA, which was dramatically improved by selectively removing oxygen atoms from the HPA by cycling the fuel cell cathode under N2 followed by reoxidation to give a restructured oxide catalyst. The nanostructured oxide achieved an OCV of 0.7 V with a Tafel slope of 115 mV/decade. Cycling the same catalysts in oxygen resulted in an improved catalyst/ionomer/carbon configuration with a slightly higher Tafel slope, 128 mV/decade but a respectable current density of 100 mA/cm2 at 0.2 V. 相似文献
70.
A nanosized silica particle was used as the support to prepare an Et[Ind]2ZrCl2/MAO catalyst for propylene polymerization of polypropylene. The catalyst and the polymer produced were characterized with nitrogen adsorption, ICP, DSC, SEM, TEM, XRD, solution viscometer, 13C NMR and optical microscopy. The effects of polymerization temperature and [Al]/[Zr] ratio on catalyst activity and polymer melting point were investigated. Under identical reaction conditions, nanosized catalyst exhibited better polymerization activity than the microsized catalyst (e.g., the former had 64% higher activity than the latter at the optimum polymerization temperature (50°C) and [Al]/[Zr] = 570). DSC results indicated that polymer melting point increased with the increase of [Al]/[Zr] ratio and with the decrease of polymerization temperature. XRD results showed that the percentage of γ crystals increased with decreasing [Al]/[Zr] ratio. Electron microscopic results showed that the polymer particle size increased with increasing polymerization temperature. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2573–2580, 2006 相似文献