汽车尾气催化转换器中的催化材料

介绍汽车尾气催化转换器中的催化材料一三元催化剂，以及贵金属催化剂，过渡金属氧化物催化材料，复合化合物催化剂，催化剂制备。     

金属污染本质的探讨

现代工业的发展对金属材料提出了严格的要求，金属的防污染问题已变得愈来愈重要，本文从异类金属，非金属元素及其化合物对金属的污染着手，探讨了在高温和低温下金属污染的本质。     

钯碳催化木质素模型化合物制备烷烃的试验研究

针对木质素的转化,以木质素模型化合物愈创木酚催化加氢脱氧制备烷烃为模型反应,研究酸溶液中,活性炭负载Pd、Pt、Ru、Rh金属催化剂的催化性能。研究发现:在测试的催化剂中,Pd/C催化剂显示出较高催化加氢脱氧性能,烃类产物收率达到80%。随后,考查反应条件对催化性能的影响,发现在适中反应温度(200~250℃)、酸浓度(0.5wt%~1.0wt%)和较高氢气压力(5MPa)下,反应有利于烃类产物的生成。最后,探讨愈创木酚加氢脱氧的反应历程。     

碱金属化合物阴离子团对油页岩燃烧特性影响

以富含钠金属化合物的桦甸油页岩为研究对象,采用热重技术和燃烧动力学相结合的方式,探究了CO_3~(2-)、OH~-及Cl~-3种阴离子团对碱金属化合物催化油页岩燃烧行为的影响规律.结果表明:CO_3~(2-)和OH~-对促进油页岩中有机物分解具有明显作用,而Cl~-则有利于固定碳的燃烧.NaOH的加入使油页岩的综合燃烧指数达到最大值.基于高斯分峰拟合Coats-Redfern法和Friedman法的计算结果表明,由CO_3~(2-)、OH~-及Cl~-组成的钠金属化合物使油页岩燃烧主要阶段的表观活化能分别降低了9.42 kJ/mol、9.10 kJ/mol及1.09 kJ/mol.经综合分析,OH~-与碱金属阳离子间的协同作用对提升油页岩综合燃烧性能较为显著.     

有机红外光电器件及其制备方法

本发明涉及一种基于超大环金属酞菁化合物的有机红外光电器件及该器件的制备方法。有机光电器件由玻璃或柔性透明衬底、透明或半透明薄膜下电极、有机／聚合物光活性层和金属薄膜上电极组成。其中有机／聚合物光活性层是在真空10-Pa条件下，用石英舟或钼舟加热超大环金属酞菁化合物进行热蒸发获得，热蒸发温度为600-900℃；也可将超大环金属酞菁化合物溶解到二甲亚基砜（DMSO）溶液中，旋涂到ITO玻璃上，然后在普通机械泵能达到的低真空条件下烘烤干燥获得。     

煤焦水蒸气催化气化动力学分析

利用固定床反应器研究了K、Ca、Ni和Fe金属对600～900℃内煤焦水蒸气气化的催化效果，分析了适用于原煤焦、脱灰煤焦和添加K、Ca、Ni和Fe金属后的煤焦水蒸气气化动力学模型。     

生物油在钌镍双金属催化剂下加氢脱氧制备液体燃料

研究了生物油及其模型化合物在RuNi双金属催化剂作用下加氢脱氧制备烃类液体燃料。实验比较了单金属催化剂与双金属催化剂的反应效果,结果表明双金属催化剂的催化活性更高。在260℃下,RuNi双金属催化剂催化愈创木酚反应,可基本转化为环己烷,而单金属Ru催化剂转化率只有49.4%,单金属Ni催化剂转化率很低。该RuNi双金属催化剂用于生物油的加氢脱氧也有很好的效果,在280℃下,生物油中的碳氢化合物含量从反应前的15.6%增加到反应后的63.0%。     

过渡金属碳化物的催化研究

过渡金属碳化物作为一种催化新材料得到了人们广泛的关注，在催化加氢、脱氢、脱硫（HDS）、脱氮（HDN）和重整等方面，表现出优良的催化活性和选择性。本文综述了碳化钒、碳化钼、碳化钨、碳化铁、碳化钛等碳化物的催化性能在国内外的研究进展和碳化物在各个反应中的催化机理。     

催化裂化装置掺炼乙烯黄油成功

乙烯黄油进催化裂化装置是扬子石化公司今年重点技改工程之一，它是发挥催化装置的技术潜能．把乙烯生产过程中产生的黄油作为催化汽油生产原料。进行再次加工处理，有效提高产品的附加值。催化装置掺炼乙烯黄油技措工程是今年2月份破土动工，3月份中旬建成投运。由于黄油成分较重．含有不少金属钠离子，容易对催化剂造成损伤，[第一段]     

氮氧化物的危害及其催化还原控制方法

对大气中氮氧化物的危害及其控制方法进行了综述,总结了氮氧化物的主要来源、排放情况及其危害。着重探讨选择性催化还原方法、金属及其氧化物催化还原方法两种氮氧化物的催化还原控制方法。     

High-rate capability of zinc anodes in alkaline primary cells

This work is devoted to the electrochemical aspects of high-power testing of primary alkaline LR6 (“AA”) cells and to the factors influencing cell performance, namely the corresponding zinc anode behaviour under such high-rate conditions. The influence of the high-rate testing regime, such as the discharge mode and the end-potential, on zinc utilisation in alkaline cells has been monitored and its behaviour has been isolated by means of a pseudo-reference electrode.As anticipated, anode formulation, including zinc alloy composition and size distribution, is found to affect the cell’s discharge curve and the corresponding zinc electrode potential and utilisation. The effects of these parameters on the discharge curve are discussed in terms of three stages of discharge.Finally, the high-rate capability of commercial LR6 cells is analysed in terms of zinc anode formulation. It was concluded that zinc electrode polarisation is very small and is relatively independent of manufacturer, of zinc anode formulation and of zinc alloying. On the other hand, metallic zinc utilisation remains very low under high-rate conditions.     

A two-pass solar air heater

An air heater, in which the air first flows between metallic and cover plates and is then made to flow between two metallic plates in opposite direction, is discussed theoretically. The governing equations of the model are solved explicitly under suitable conditions. The measured values of the solar insolation and ambient temperature are represented by Fourier series. The effects of collector length and flow rate have been studied. The air heater in this mode of operation is more efficient than one in which air flows between two metallic plates in the same direction, provided the plate length is less than 5 m.     

Research and development at the UNICAMP laboratory of hydrogen, Brazil, 1975–1992

This article presents the research and development efforts that have been made in the Laboratório de Hidrog nio of Universidade Estadual de Campinas, Brazil, since the beginning of the laboratory in 1975. The topics are based on hydrogen production from alkaline water electrolysis, gas purification (up to 99.999% purity), conventional and metallic hydride hydrogen storage, conventional and thermochemical hydrogen compression, and the utilization of hydrogen as a fuel in vehicles. Other topics also studied are the following: electrodeposited surfaces for alkaline water electrolysis; hydrogen effects on metals; ultrapure gas analysis, including the production of standards for quantitative analysis; the production of metallic standards to analyse hydrogen in metals; and study of new metallic hydrides.     

Theoretical analysis on the role of annular metallic shapes for microwave processing of food dielectric cylinders with various irradiations

A theoretical analysis has been carried out to analyze efficient microwave assisted heating processes of food cylinders with various shapes of metallic annuli in presence of lateral and radial irradiation. Lateral irradiation represents the sample incident at one direction with source at infinity whereas the radial irradiation represents the situation where the sample is incident with microwave radiations from co-axial cylindrical cavity at infinity. A generic finite element method has been used to obtain computational mesh for all shapes of metallic annulus and Galerkin finite element method has been used to solve electric field and energy balance equations. Influence of metallic annulus has been illustrated for three representative sample lengths or regimes (I, II and III) as a function of wave number (N_w). Sample radius with regime I is smallest and largest sample radius corresponds to regime III. In general, power absorption due to lateral irradiation is larger for regime I whereas identical power with lateral or radial irradiation or larger power absorption with radial irradiation corresponds to regime II in absence of metallic annulus. The metallic annuli are found to enhance power absorption or heating rate for specific aspect ratios of both bread and beef samples. The aspect ratios are defined as the ratio of the dimension of metallic annulus and outer radius of the food sample. Lateral irradiation is found to give larger heating rates especially for regimes II and III for bread samples (low dielectric loss), but radial irradiation gives smaller degree of thermal runaway. On the other hand, radial irradiation gives significantly large heating rates with minimal thermal runaway for beef samples (high dielectric loss) with all regimes. It is interesting to observe that the metallic annuli enhance two to three times microwave power for beef samples involving regimes II and III. Various shapes of metallic annuli are also found to play dominant role either to focus or to optimize heating effects.     

Corrosion resistance characteristics of stamped and hydroformed proton exchange membrane fuel cell metallic bipolar plates

Metallic bipolar plates have several advantages over bipolar plates made from graphite and composites due to their high conductivity, low material and production costs. Moreover, thin bipolar plates are possible with metallic alloys, and hence low fuel cell stack volume and mass are. Among existing fabrication methods for metallic bipolar plates, stamping and hydroforming are seen as prominent approaches for mass production scales. In this study, the effects of important process parameters of these manufacturing processes on the corrosion resistance of metallic bipolar plates made of SS304 were investigated. Specifically, the effects of punch speed, pressure rate, stamping force and hydroforming pressure were studied as they were considered to inevitably affect the bipolar plate micro-channel dimensions, surface topography, and hence the corrosion resistance. Corrosion resistance under real fuel cell conditions was examined using both potentiodynamic and potentiostatic experiments. The majority of the results exhibited a reduction in the corrosion resistance for both stamped and hydroformed plates when compared with non-deformed blank plates of SS304. In addition, it was observed that there exist an optimal process window for punch speed in stamping and the pressure rate in hydroforming to achieve improved corrosion resistance at a faster production rate.     

First-principle investigation for the hydrogen storage properties of NaXH3 (X= Mn,Fe, Co) perovskite type hydrides

In the present study, NaXH₃ (X = Mn, Fe, Co) perovskite type hydrides have been investigated by performing first-principles calculation. The results of the structural optimizations show that all these compounds have negative formation energy implying the thermodynamic stability and synthesisability. The mechanical stability of these compounds has been studied with the elastic constants. Moreover, the polycrystalline properties like bulk modulus, Poisson's ratio, etc. have been obtained using calculated elastic constants of interest compounds. The electronic properties have been studied and band structures have been drawn with the corresponding partial density of states. These plots indicated that NaXH₃ hydrides show metallic characteristics. The charge transfer characteristics in these compounds have been studied with the Bader partial charge analysis. The phonon dispersion curves and corresponding density of states indicated that NaXH₃ compounds are dynamically stable compounds. The investigation on hydrogen storage characteristics of NaXH₃ compounds resulted in hydrogen storage capacities of 3.74, 3.70 and 3.57 wt% for X = Mn, Fe and Co, respectively. The present study is the first investigation of NaXH₃ perovskite type hydrides as known up to date and may provide remarkable contribution to the future researches in hydrogen storage applications.     

柴油机金属丝纤维过滤器的模型改进和试验验证

本文建立了改进的柴油机颗粒过滤器的计算模型，计算模型结合流场计算结果和对初始条件的假设，考虑了纤维过滤体下游流动的涡流对颗粒的卷吸作用，并探讨了大尺寸颗粒在纤维表面的吸附效应对过滤效率的影响。计算结果表明，涡流和颗粒在纤维表面的吸附效应，使得纤维过滤效率高于不考虑这些效应时的计算结果，改进模型能够更好地符合试验结果。     

SIZE EFFECTS ON THE THERMAL CONDUCTIVITY OF THIN METALLIC WIRES: MICROSCALE IMPLICATIONS

This study examines the influence of radial thickness on the thermal conductivity of thin metallic wires. While size effects on the electrical conductivity of thin wires have been discussed in the literature, research into size effects on thermal conductivity still requires investigation. At such small length scales, the assumption that the reduced electrical conductivity can be simply related to the reduced thermal conductivity through a Wiedemann-Franz relation is subject to question. This study uses the Boltzmann transport equation for electrons to determine the thermal conductivity of a thin wire directly. Electrons are treated as the primary heat carriers in a thin wire with a thermal gradient along the axis. A single-crystal, defect-free, metallic thin wire is considered in the derivation. An expression is presented which accounts for the radial size effects on axial thermal conductivity. The derived thermal conductivity is compared to expressions for the reduced electrical conductivity, and the applicability of the Wiedemann-Franz relation is discussed.     

A novel composite negative electrode consist of multiphase Sn compounds and mesophase graphite powders for lithium ion batteries

A modified electroless plating technique was adopted to prepare the Sn compounds/mesophase graphite powders (MGP) composite electrode. Characterization of the composite material showed that multiphase Sn compounds were uniformly deposited on MGP. The multiphase composition which contained metallic Sn, SnP₃ and SnP₂O₇ were expected to provide a higher spectator to Sn ratio for improved cycleability. During cycling between 0.001 and 1.5 V, the charge capacity was greatly enhanced without appreciable fading. From the voltage profiles and cyclic voltammetry (CV) curves, it was revealed that the capacity fading was caused by either the formation of insulated LiP in the early stage or by aggregation of metallic Sn after prolonged cycling. For improving the cycleability, the cut-off voltage was lowered from 1.5 to 0.9 V. Adjusting the voltage range was manifested to be an effective way for obtaining superior cycling performance in the Sn–P–O/MGP composite negative electrode. The capacity retention was as high as 96% of the highest capacity after charge/discharge between 0.001 and 0.9 V for 45 cycles.     

Hydrogen trapping: Synergetic effects of inorganic additives with cobalt sulfide absorbers and reactivity of cobalt polysulfide

The biphasic product CoS₂ + Co(OH)₂ obtained by oxidation of cobalt sulfide is known to trap hydrogen at room temperature and low pressure according to a balanced reduction equation. Adding various inorganic compounds to this original absorber induces their reduction by hydrogen in the same conditions at a significant rate: (i) excess cobalt hydroxide is reduced to metallic cobalt; (ii) nitrate ions are reduced to ammonia; (iii) sulfur and sodium thiosulfate are reduced to H₂S or NaHS and Na₂S, respectively. Without a hydrogen absorber these inorganic compounds are not reduced by H₂, suggesting synergetic effects involving H₂ and the hydrogen absorber. Amorphous cobalt polysulfide, CoS₅, is also reduced by hydrogen at room temperature and releases H₂S gas. In the presence of a base to neutralize H₂S gas, the reaction rate is initially slower than with the CoS₂ + Co(OH)₂ mixture due to the higher stability of polysulfide chains but the H₂ trapping yield is improved, making CoS₅ a good candidate for H₂ trapping.