质子交换膜燃料电池中抗CO中毒的PtM阳极催化剂

介绍了PtM阳极催化剂加入第二金属组分后对Pt晶体结构、颗粒大小、分散度等方面的影响以及PtM相互之间、PtM与载体之间的相互作用。由于存在这些相互作用，使其改变了Pt的CO中毒特性，导致了不同的反应活化能、反应级数以及CO的表面覆盖率。评述了目前几种主要的催化剂抗CO中毒机理及三组分和多组分催化剂的研究进展。     

Effect of Phosphorus Ions on the Proton Conductivity in the Sol–Gel-Derived Porous Glasses

The effect of phosphorus ions on the proton conductivity was examined for the sol–gel-derived glasses. The porous glasses were prepared through hydrolysis of PO(OCH₃)₃ and Si(OC₂H₅)₄, in which the phosphorus ions consisted of the POH bonds and were dissolved into the silica matrix without any P-O-Si bond. The electrical conductivity increased in a humid atmosphere and reached ∼30 mS/cm at 50°C under 70% RH. High conductivity is achieved by both the POH bonds and the molecular water bonded to the POH bonds. The conductivity increased with a change in humidity from 40% to 80% RH. The phosphorus ions were selectively dissolved in water, resulting in a lower conductivity.     

High-Temperature Proton Conductors for the Injection of Hydrogen into a Vacuum

Tubes of ceramic high-temperature proton conductors (CaZr_0.9In_0.1O_{3− x} ,BaZr_0.9Y_0.1O_{3− x} , and Ba₃Ca_1.18Nb_1.82O_{9− x} )were used to introduce hydrogen into a vacuum system. A prerequisite was a leak rate below 10⁻⁸mbar/s for an assembly consisting of the active tube and a 8YSZ support tube. Mass spectrometry showed that the partial pressure of hydrogen in the vacuum system, p _H2, increased linearly with the electric current flowing through the proton conductor. All other important partial pressures remained unaffected by this operation. Calculation of throughput during operation of the hydrogen source essentially revealed that the total current, J , is used to transport protons from the anode to the cathode ( t _H∼ 1). The number of moles of H₂ transported per second is given by J /2 F . In essence, the present proton conductor tube constitutes a precise, current-controllable device, with a response time of a few seconds only, that delivers ultrahigh-purity hydrogen to a vacuum system.     

基于Pro／E隐形眼镜盒盖的注塑模具设计

采用Pro／Engineer来实现隐形眼镜盒盒盖的三维设计及模具成型零件设计，通过Plastic Advisor模块分析制件的进浇点及成型质量，再采用EMX组件来实现模架的装配，并在产品设计及模具装配过程中，辅助以必要的理论计算，将数字化设计与理论计算结合起来，可以大大缩短产品研发周期、模具设计周期，提高产品设计及模具设计的准确性、产品成型质量，降低产品研发、模具设计成本。     

基于Pro／E隐形眼镜盒盒盖的注塑模具设计

采用Pro／Engineer来实现隐形眼镜盒盒盖的三维设计及模具成型零件设计，通过Plastic Advisor模块分析制件的进浇点及成型质量，再采用EMX组件来实现模架的装配，并在产品设计及模具装配过程中，辅助以必要的理论计算，将数字化设计与理论计算结合起来，可以大大缩短产品研发周期、模具设计周期，提高产品设计及模具设计的准确性、产品成型质量，降低产品研发、模具设计成本。     

Investigation of Glasses Using Surface Profiling by Spectrochemical Analysis of Sputter-Induced Radiation: II, Field-Driven Formation and Electrochemical Properties of Protonated Glasses Containing Various Proton Concentrations

The ion-sputtering technique for measuring concentration profiles in glass surfaces provides a method for studying ionic transport in solids. Simultaneous field-driven lithium ion and proton transfer from solutions into, and migration of these ions within, several lithium silicate glasses was investigated quantitatively. This work leads to the new field of protonated glasses which are distinguished by the availability of all sites to both cationic species. Conductivity and mobilities reported as a function of concentration (50°C) do not exhibit the typical features of the mixed-alkali effect. Mechanisms are proposed for ionic transfer across solution-glass interfaces and for migration of ions within protonated glasses. Small proton mobilities at low proton concentrations are explained in terms of specific sites which function as proton traps and are identified by infrared spectroscopy. The condition for stability of boundaries between migrating ions is discussed.     

基于CAE技术的眼镜支架注塑模的模具设计及成型分析

分析了带有嵌件的眼镜支架的结构及成型工艺特点,设计了对应的注塑模模具,并利用CAE技术的塑料注射成型软件Moldflow对制件进行了预成型。制件注射过程中气穴较少、纤维取向内外层基本一致,制件性能稳定;缩痕指数表明制件的冷却相对均衡、残余应力较小。综合分析结果表明,塑件成型质量较好,一模四件的对称性分布模具结构简单合理,可行性好。     

Nucleation in ZBLAN Glasses

Nucleation rates were measured in a ZrF₄–BaF₂–NaF–LaF₃–AlF₃ glass (ZBLAN) using an optical technique. The results were compared with a similar glass having a slightly different composition. The difference in the nucleation rate is explained by classical nucleation theory using calculated free-energy differences between the ZBLAN liquid and the BaZrF₆ crystal, which is found as the precipitating phase.     

光学玻璃进展

总结了1982年《光学玻璃》出版以来光学玻璃品种和制造技术方面的进展,包括光学玻璃质量和检测标准的提高,特高、特低折射率新品种玻璃牌号,无铅无砷环保玻璃,光学玻璃连续熔炼和直接压型,非球面透镜精密模压和精密型料等。     

Substructures in Silicate Glasses

Glass compositions are correlated with published data for refractive index, specific volume, and fluidity, which indicate the presence of different structural types in silicate glasses. These structural types are shown to be uniquely related to the composition areas of primary crystallization phase fields. It is suggested that these different structural types are to be understood as silicate framework structures or "substructures" in which other appropriate cations may be accommodated. The described data relations definitely establish the presence of different recognizable substructures in silicate glasses but do not permit judgments on their detailed characteristics.     

Oxynitride Glasses

Oxynitride glasses are grain boundary phases within silicon nitride ceramics. The desire to understand their nature led to various investigations on oxynitride glass formation, structure, properties, and crystallization. This paper provides a review of oxynitride glasses and outlines the effect of glass chemistry, including nitrogen contents and cation ratios, on properties such as glass transition temperature, Young's modulus, and viscosity and relates this to structural features within the glass. A short outline of crystallization of oxynitride glasses to form glass–ceramics is presented.     

Arsenate Glasses

Stability regions were determined for a new family of glasses. Arsenic pentoxide (As₂O₅) forms binary glasses with alkali metal oxides (except Li₂O) and the known glass-formers B₂O₃, P₂O₅, GeO₂, and TeO₂. It also forms ternary glasses with Li₂O and a variety of alkaline earth, transition metal, and post-transition metal oxides when gallium oxide (and in some instances indium oxide) is present as a third component.     

Tellurite Glasses

The boundaries of regions of glass-forming compositions were determined in binary tellurite systems with alkali, alkaline-earth, and heavy-metal oxides, and in the ternary systems TeO₂-WO₃-Ta₂O₅, TeO₂-WO₃-BaO, TeO₂-WO₃-Bi₂O₃, and TeO₂-WO₃-Tl₂O. On the basis of a structural interpretation of liquid immiscibility in binary oxide systems and of X-ray diffraction investigation of the structure of tellurite glasses, a crystallochemical interpretation of glass formation is proposed, as well as a method for calculating the modifier-poor boundaries of the regions of glass-forming compositions in binary systems. An investigation of the crystallizability, density, optical constants, spectral transmission characteristics, and chemical durability of the tellurite glasses as functions of their chemical compositions has led to the development of a new flint-type optical glass, with n _d= 2.1608 and v = 17.4, possessing a high chemical durability and resistance to devitrification.     

Proton Solvation and Proton Mobility

Experimental evidence for proton solvation and proton mobility is analyzed and the results are compared with recent simulations. Three factors contribute to differences in proton solvation energies: hydrogen-bond cleavage, changes in hydrogen-bond lengths, and proton derealization. These factors are estimated from experimental attributes. In dilute acidic aqueous solutions H₃O⁺ is more stable than H₅O₂⁺ by about 0.6 kcal/mol. This estimate, together with the activation energy for proton mobility, supports the 121 mechanism for proton mobility in which a protonated water monomer is transformed, by second-shell hydrogen-bond cleavage, to a protonated dimer and back to another protonated monomer.     

含铅玻璃及其无铅化的研究

介绍了铅对人体的危害,综述了一些为限制铅的使用及排放而制定的相关法规,详细介绍了铅玻璃在现阶段中的一些主要用途和目前人们对这些玻璃的无铅化方面的工作。指出电子产品无铅化的迫切性。     

Photoelastic Effects in Phosphate Glasses

The stress-optical coefficients of RO-Pz05 glasses (R = Mg, Ca, Sr, Ba, and Zn) were measured, and the photoelasticity mechanisms were analyzed based on the equation expressing the relation among the photoelastic constants, the elastic moduli, and the refractive index of glasses. No simple relation was found between the stress-optical coefficient and the elastic modulus, indicating that the factor (p – q), where p and q are the Neumann strain-optical coefficients, is important. The change of (p – q) with glass composition is governed mainly by changes in the effect of the atoms, rather than the lattice. The atomic effect increases with decreasing radius of the divalent cation, except for Zn²⁺. The ZnO-containing glasses exhibit extraordinarily large atomic effects. The photo-elasticity mechanism is discussed in relation to the nature of the chemical bonds.