Electrochemical Faceting of polycrystalline platinum in HF solutions

The electrochemical faceting of polycrystalline (pc) platinum yielding a (100)-preferred oriented electrode surface was accomplished in HF solutions by applying to the pc platinum electrode a square wave potential perturbation at 1 kHz in the 0.2 to 1.3 V range (vs rhe). SEM patterns of the resulting surfaces were also obtained. For HF concentrations up to 2 M no appreciable influence of the electrolyte concentration on the electrochemical faceting was noticed. Otherwise, the voltammetric response of the (100)-type preferred oriented platinum surface in the H-adatom potential range when compared to previously reported data resulted remarkably sensitive to the electrolyte composition. The discussion of results was based on the non-equilibrium adsorption conditions for anions under the periodic perturbation.     

Catalytic properties and electronic structure of copper ions in Cu-ZSM-5

The effect of ion exchange conditions, such as Si/Al ratio, precursor copper salt, pH and concentration of the solution, on the catalytic activity in SCR of NO by propane and on the electronic state of copper ions in Cu-ZSM-5 has been studied. The NO conversion in NO SCR by C₃H₈ has been found to reach a maximum value at Cu/Al ratio about 0.37–0.4 and remain constant at higher Cu/Al.

ESR and UV–vis DR spectroscopy have been used to elucidate stabilization conditions of copper ions in Cu-ZSM-5 zeolites as isolated Cu²⁺ ions, chain copper oxide structures and square-plain oxide clusters. The ability of copper ions for reduction and reoxidation in the chain structures may be responsible for the catalytic activity of Cu-ZSM-5. These transformations of copper ions are accompanied by the observation of intervalence transitions Cu²⁺–Cu⁺ and CTLM of the chain structures in the UV–vis spectra.     

印染废水处理工艺研究及实例

本文简要介绍了印染废水水质特征,提出了处理工艺,并利用两个工程实例说明了该工艺的可行性.     

PTA压力离心机转子的改造

介绍了PTA压力离心机的主要性能参数、工作原理、分离效果的影响因素。为了增大沉渣在过渡区及脱水区滞留的时问，同时为达到在过渡区及脱水区对沉渣加入纯净水进行再冲洗的目的，对螺旋送料转子、挡液环、进料管进行了改造。改造后，沉渣在脱水区的停留时间由0．44a增至0．72s，2．5～3t／h的冲洗水对脱水区的沉渣进行冲洗效果较好。产品中的杂质质量分数较改造前减少15％，产品优等品率提高到99％。     

Effects of Na, Cu, Ni and Co Modifications on the Activity and Characteristics of Rh/Al2O3 Catalysts for NO Reduction

This study used different metals to modify Rh/Al₂O₃ catalysts for NO reduction in a simulated waste incineration flue gas containing 6% O₂. The characteristics of the modified catalysts were analyzed using BET, TEM and XRD. The results of the experiment reveal that Na addition can significantly affect the properties of Rh/Al₂O₃ catalysts on the BET surface area and Rh metal dispersion. Furthermore, Na addition was found to significantly enhance the NO conversion of Rh/Al₂O₃ at 250–350 °C. On the contrary, Cu, Ni, and Co addition was found to have slight suppression effects.     

二维多波束蜂窝网覆盖方法研究

提出一种基于二维多波束形成的蜂窝网覆盖方法,该方法旨在通过对平面阵阵元权矢量的控制,使所形成的波束在空域上呈非均匀蜂窝网结构,达到重点地区覆盖密度高,非重点区域覆盖密度低的目的,减小资源利用率,并重点分析了波束设计思路和权值的计算方法,仿真结果表明:该覆盖方法是有效的.