Mechanistic study of partial oxidation of methane to synthesis gas over supported rhodium and ruthenium catalysts using in situ time-resolved FTIR spectroscopy

In situ time-resolved FTIR spectroscopy was used to study the reaction mechanism of partial oxidation of methane to synthesis gas and the interaction of CH₄/O₂/He (2/1/45) gas mixture with adsorbed CO species over SiO₂ and γ-Al₂O₃ supported Rh and Ru catalysts at 500–600°C. It was found that CO is the primary product for the reaction of CH₄/O₂/He (2/1/45) gas mixture over H₂ reduced and working state Rh/SiO₂ catalyst. Direct oxidation of methane is the main pathway of synthesis gas formation over Rh/SiO₂ catalyst. CO₂ is the primary product for the reaction of CH₄/O₂/He (2/1/45) gas mixture over Ru/γ-Al₂O₃ and Ru/SiO₂ catalysts. The dominant reaction pathway of CO formation over Ru/γ-Al₂O₃ and Ru/SiO₂ catalysts is via the reforming reactions of CH₄ with CO₂ and H₂O. The effect of space velocity on the partial oxidation of methane over SiO₂ and γ-Al₂O₃ supported Rh and Ru catalysts is consistent with the above mechanisms. It is also found that consecutive oxidation of surface CO species is an important pathway of CO₂ formation during the partial oxidation of methane to synthesis gas over Rh/SiO₂ and Ru/γ-Al₂O₃ catalysts.     

Green State Joining of Silicon Carbide Using Polycarbosilane

Green state joining of SiC was investigated using a paste consisting of polycarbosilane polymer and SiC powder. The joining process and densification were described. Initial experiments resulted in the formation of symmetrical black bands and cracks on both sides of the joint. However, with modifications in processing conditions, the cracks were eliminated and the resulting joints were indistinguishable from the matrix. The flexural strength of joined samples was measured to be 234 MPa, which was comparable to that of the control sample with similar density. As the applied pressure during joining was increased from 34 to 138 MPa, the strength of the joined samples increased from 180 to 250 MPa.     

年产120吨聚丙烯酸钠絮凝剂的工艺设计与投产

介绍了新开发的生产工艺过程及工艺条件,对120吨/年的工厂设备选型、工厂经济分析及其应用效果作了简要评述。     

高氮量硝化棉的脱硝反应动力学研究(英文)

用实时测定凝聚相分解产物的固体原位反应池/快速扫描傅立叶变换红外光谱热技术研究了高氮量硝化棉(14.14%N)的脱硝反应动力学。该反应的动力学参数(活化能和指前因子)用改良的Coats-Redfern法计算。根据所得结果,提出了在403～465K温度范围内描述高氮量硝化棉脱硝反应的微分动力学方程。     

Heat Generation in Multilayer Piezoelectric Actuators

Multilayer piezoelectric actuators when driven under high frequency, generate significant heat, which influences the reliability and other piezoelectric properties. In this paper, heat generation in various types of multilayer PZT-based actuators was studied. Experimental results showed that heat generation is mainly caused by ferroelectric hysteresis loss in the stress-free state. A simplified analytic method was established to evaluate the temperature rise, which is useful for the design of multilayer and other high-power actuators.     

掺混纳米微粉的聚碳硅烷熔融纺丝工艺研究

运用功率超声将纳米Ｎｉ粉均匀分散到聚碳硅烷（ＰＣＳ）中，通过熔融纺丝制备出了直径约１５～３５μｍ的有机纤维。研究了超声过程对纳米微粉分散状态的影响及掺混型ＰＣＳ熔融纺丝的工艺条件。     

CVD-ZnS中与锌有关的晶体缺陷及其对光学性能的影响

采用化学气相沉积（ＣＶＤ）法制备了红外晶体ＺｎＳ块材料。用氩气作为载体，反应气体为硫化氢和锌蒸气。ＸＰＳ，ＩＲ及能谱分析表明：当沉积温度低于锌蒸发温度时，生成的ＺｎＳ中与锌有关的晶体缺陷有Ｚｎ—Ｈ功能团及存在于花瓣状形态中心的锌微粒夹杂；当沉积温度高于锌蒸发温度时，锌微粒夹杂消失，且随沉积温度的升高Ｚｎ—Ｈ含量减少，Ｚｎ—Ｈ对红外光在６．２μｍ波长处的吸收峰减弱，使生成的ＺｎＳ具有高的红外透过率。     

高温水采暖系统内部氧腐蚀

对阜康冶炼厂高温水采暖系统内部产生氧腐蚀的原因进行分析，采取相应的措施，收到良好的效果     

超扭曲向列相液晶显示技术及其进展

介绍了超扭曲向列相液晶显示器的工作原理，应用范围，评述了该类显示器的技术现状及发展趋势。对液晶材料的要求以及国内研制动态。     

Effect of pH Value on Electroless Deposition of Copper Graphite Powders

Protection of Metals and Physical Chemistry of Surfaces - The effect of pH value on the electroless deposition of copper coated graphite powders (Cu@GPs) was investigated in this paper. The...