Selective oxidation of alcohols using octahedral molecular sieves: influence of synthesis method and property–activity relations

Manganese oxides having a tunnel structure (OMS-2) have been utilized as selective catalysts for alcohol oxidation. In this study manganese oxide catalysts were synthesized in different media and modified by exchanging the tunnel cation by H⁺, using acid treatment or exchanging with NH₄⁺ followed by thermolysis. Various alcohol oxidations were performed using these catalysts to ascertain the influence of synthesis method on their activity. A correlation is made between lattice oxygen instability and activity of the catalysts, which indicates involvement of the lattice oxygen in the mechanism. The exchange of the tunnel cation with the smaller H⁺ ions leads to weakening of the Mn–O bond, as verified by temperature programmed desorption (TPD) results. Only the chemisorbed oxygen on the surface (O⁻) and the lattice oxygen in the layers close to the surface is involved in the oxygen transfer during the reaction.     

大连电视台分量电视车视频系统设计特点

本文介绍亚州第一台模拟分量电视车视频系统的设计思想,比较详细地阐述了该车的各种功能,总结了不同于复合电视车的新特点。     

基于感知器的快速彩色图像无损压缩算法

针对彩色图像像素和颜色分量之间存在的相关性，将神经网络中的感知器技术引入彩色图像的无损压缩算法中，提出了一种新的预测模型。应用感知器的自学习和自适应能力，对预测值进行自适应调整，使算法在运行过程中具有很小的预测残差并具有较小的动态范围。同时应用颜色空间变换来减小颜色分量间的相关性。相对于新的国际标准JPEG—LS，这种预测模型具有较低的计算复杂性。对比实验结果说明，这种算法的性能明显优于传统算法，在压缩比损失很小的前提下，其执行速度高于JPEG—LS。     

多层复合膜的成型技术

阐述了用AutoLisp程序模拟塑料熔体在2层复合膜机头内的流动情况，并介绍了复合膜机头的内部结构。     

封闭插接母线施工工艺

从工艺原理、流程、操作要点、质量要求等不同侧面介绍了封闭插接母线的施工方法，提出了应注意的安全事项，通过效益分析表明，此法具有工期短、节省人力、工序先进、效益显著等优点。     

Structure evolution of conductive polymer composites revealed by solvent vapor induced time-dependent percolation

The authors of this paper synthesized a series of amphiphilic triblock copolymers of polystyrene-b-poly(ethylene glycol)-b-polystyrene (PS-PEG-PS) having different PEG/PS ratios with nearly identical molecular weights of the entire copolymers. The interfacial interactions in the composites consisting of carbon black and the copolymers can thus be tailored. When these conducting composites are exposed to certain solvent vapors, their electrical resistances greatly increase, showing the gas sensitivity. The present work indicated that this switching behavior is controlled by the structural relaxation of the composites because matrix swelling acts as the main mechanism. The response time has been correlated with absolute temperature by Arrhenius equation, and the estimated activation energy reflects mobility of the fillers involved in the solvent induced expansion of the surrounding polymer. Therefore, by using the gas sensibility of the conductive composites, the structure evolution of the composite materials in solid state and the effect of filler/matrix interfacial interaction on the relaxation property of the matrix polymer has been inspected. It was found that lower activation energy represents stronger interfacial interaction in case good solvent of the matrix was used for the test.     

电信号码编排的建议——使用电话名

介绍了电话名的概念 ,并主要针对电话名系统的实现、应用及前景做了相应的分析     

Improved domino logic for high speed design

Techniques are introduced to improve the speed of domino logic. With an inverted clock scheme, a serial transistor is removed and capacitances at the output node are reduced in the new structures. HSPICE simulation shows that over 20% performance enhancement is achieved.     

变频器的常见故障分析

本文阐述了变频器的常见故障，并针对常见故障提出了解决措施。