Effect of promoters on the behavior and properties of VPO catalysts for the selective oxidation of n-butane to maleic anhydride

A series of vanadyl pyrophosphate (VPO) modified by several additives has been investigated with the aim to reveal the promotion mechanism of the additives for selective conversion of n-butane to maleic anhydride (MA). Catalyst performance and various physicochemical characterization including XPS, XRD, FT-IR, DTA and BET indicated that the properties of additives, such as electronegativity and ion radius, contributed much to the effect of the additives on the structure and surface characteristics of VPO catalysts, and then influenced the catalytic behavior. The remarkable effects of additives on the surface vanadium and oxygen species were discussed. It was shown that maximum MA selectivity could be found with a moderate V⁵⁺ /V⁴⁺ ratio, and the catalytic activity and selectivity were improved, respectively, with the increase of surface active oxygen species, as well as as their amount and stability.     

态|ψ5(3)〉q中广义电场的2(2m+1)次方Y压缩特性

利用多模压缩态理论,研究了由多模复共轭相干态|{Z_j^*}〉_q(j =1,2,3,…,…,q)、多模复共轭相干态的相反态|{-Z_j^*}〉_q和多模虚相干态|{iZ_{j}〉q的线性叠加所组成的第Ⅴ类三态叠加多模叠加态光场|ψ5⁽³⁾〉q中广义电场分量的等幂次N次方Y压缩特性 .结果发现 :当压缩次数N=2 p且p=2m+1(m=0,1,2,…,…)时,在一定的条件下,态|ψ5⁽³⁾〉q的广义电场分量(即第二正交相位分量)可呈现出周期性变化的、偶数次的等幂次2(2m+1)次方Y压缩效应 .}     

亚硝基甲胺异构化的量子化学研究

此文用ＭＮＤＯ方法研究了亚硝基甲胺异构化反应的机理。     

On the Residues of Binomial Coefficients and Their Products Modulo Prime Powers

In this paper, we show several arithmetic properties on the residues of binomial coefficients and their products modulo prime powers, e.g., for any distinct odd primes p and q. Meanwhile, we discuss the connections with the prime recognitions. Received November 5, 1998, Accepted December 7, 2000.     

并行FORTRAN程序设计技术探索

简要叙述了并行程序设计语言ＣＭＦｏｒｔｒａｎ的计算模式、并行数据结构及其主要特征．并对Ｆｏｒｔｒａｎ７７和Ｆｏｒｔｒａｎ９０上的扩展部分作了概要描述．     

用光谱烧孔研究卟啉掺杂的高分子薄膜中电子－声子的相互作用

本文对电子给体、受体双掺杂在高分子薄膜中形成的光谱烧孔体系，做温度循环实验，研究体系中电子－声子的相互作用，得到了表征电子－声子耦合强度的黄昆因子和薄膜中局域振动的声子频率．     

准二维电荷密度波导体钾紫青铜KxMo6O17单晶样品的制备

采用碳酸盐替代高钼酸盐电解还原的方法成功制备出了准二维电荷密度波导体钾紫青铜单晶.通过x射线衍射、透射电子显微术等方法对单晶进行结构分析表明：晶胞参数a=b=0.5540nm，c=1.3508nm，单晶为三角晶系，对称群为P3.电阻温度关系曲线的测量显示：钾紫青铜K_xMo₆O₁₇单晶在112K附近发生金属到金属的Peierls相变. 关键词： 钾紫青铜 电荷密度波 Peierls相变     

弹性撞击速度的激光分束测量技术

 研制了一个激光分束测速系统。它由一台4mW He-Ne激光器，一个将单束激光分成10束相互平行的等间距（间距为5 mm）激光的分光器，一个高灵敏度、工作状态自检、可进行波形合成、10路接受、一路输出的光电接收转换装置，一台数字存贮示波器，以及微型计算机组成。可进行弹性撞击速度的测量。     

Correlation of the Dielectric Properties of Dispersed Particles with the Electrorheological Effect

The dc field rheological properties and frequency dependent dielectric properties of a set of electrorheological (ER) fluids composed of oxidized polyacrylonitrile or aluminosilicate materials dispersed in silicone oil were examined in this paper. Our experimental investigations show that there is a complicated relationship between the dielectric properties of dispersed particles and the ER effect. The dielectric loss of dispersed particles, which has not attracted much attention in previous work, was found to play a considerable role in ER response. The large dielectric loss tangent, experimentally around 0.10 at 1000 Hz, is found to be needed for a strong ER effect. A good ER solid material should first have large dielectric loss, and then the higher the dielectric constant, the stronger the ER effect. The large dielectric loss would facilitate the turning of dispersed particles, and the high dielectric constant would maintain the fibrillation structure stable and strong. Two processes, the particle turning process and the particle polarization process, are thought to be involved in ER activity. Our findings, in connection with the Wagner model, can better explain why the strongest ER effect occurs at particle conductivity of 10⁻⁷S/m; why the shear stress of some ER fluids decreases with frequency while with others the shear stress increases with frequency; and why trace water can enhance the ER effect considerably, which would help in understanding the mechanism of the ER effect. Too large a dielectric loss is thought to be unfavorable for the ER effect, and its suitable range is worth further study. The results also present a method of designing high performance ER fluids, which would significantly promote development of electrorheology and its application in industrial areas.     

小波级数的Bouligand维数(英)

本文讨论小波级数的上、下Buoligangd维数，在小波级数满足一定的条件下，给出了与Weierstrass函数相应的结果．