苯乙烯在三氯化铁/联吡啶/1-溴乙基苯催化体系中聚合

用三氯化铁-2,2'-联吡啶-1-嗅乙基苯催化聚合苯乙烯,研究了聚合反应条件对聚合的影响,三氯化铁/2,2'-联吡啶/1-溴乙基苯摩尔比对聚合的影响,用凝胶渗透色谱研究了分子量和分子量分布。     

轮胎内衬层胶片卷取装置控制系统的研究

为实现轮胎内衬层胶片的恒张力卷取 ,采用扭矩控制 ,在卷取转速调节过程中加入半径调节的影响 ,通过变频调速使卷取转速同步跟踪牵引转速。在此基础上构成由计算机、PLC及变频器等组成的硬件系统 ,并应用恒张力控制原理分析了卷取张力不恒定的原因 ,提出了改进措施     

用Visual C++实现PLC实时监控

用VisualC + +和MFC开发了上位机和PLC的通讯系统 ,给出了系统的通讯原理和软件设计方法。运行结果表明 ,此方法简单、稳定、实用性强     

Influence of calcination temperature on structural and optical properties of TiO2-SiO2 thin films prepared by sol-gel dip coating

We prepared TiO₂-SiO₂ thin films with various TiO₂/SiO₂ ratios by sol-gel dip coating method and explored the dependence of their structural and optical properties on calcination temperature. The absorption peaks relevant to Si—O, Si—O—Ti and Ti—O bonds appeared in the FTIR spectra. With increasing TiO₂ content, the intensity of Si—O bond peaks decreases and that of Ti—O bond peaks increases. The XRD results show that the temperature of transformation from amorphous to anatase phase is lowered as TiO₂ content increases. The crystallite size of anatase phase in composite thin films increases with increasing TiO₂ content and calcination temperature. At 1000°C, the mixed phase of anatase and rutile appears in the pure TiO₂ thin films. The rutile films are denser than the anatase films. The increase in refractive index of composite thin films with calcination temperature is related to the decreased thickness and increased density as a result of evaporation of water and organic matters below 400°C. On the other hand, it is related to the change in the crystal phase and crystallite size of the films over 400°C.     

Growth of Hydroxyapatite Crystal in the Presence of Organic Film

The growth of hydroxyapatite (HAp) crystal in the presence of hexadecylamine was investigated. Due to its high polarity and high charge density, the organic film could increase the ion supersaturation on its surface. Therefore the growth of pure HAp crystals was accelerated. Moreover, the positive headgroups of the organic film could act as recognized nucleation sites and orient the growth of HAp crystals along the <0001> direction.     

电缆故障指示器及其使用情况评析

本文通过介绍近年来在广州供电分公司配网中使用较为广泛的三种电缆故障指示器,分析论述了其在查找故障点等方面的优势,同时也指出了其在使用过程中存在的问题,并提出了解决问题的方法。     

Ordinal scheduling problem and its asymptotically optimal algorithms on parallel machine system

Consider a resource allocation problem on the following system. A system consists of m identical parallel machines and is alive only when all the machines are alive. To keep a machine alive, it requires resources (material, fuel, etc.). Resources with various sizes arrive one by one and the goal is to keep the system alive as long as possible. The problem has applications in many areas such as sequencing of maintenance actions for modular gas turbine aircraft engines[1]. Using scheduling term…     

A new second-order method for blind signal separation from dynamic mixtures

This paper presents a new approach to separate colored stationary signals mixed by convolutive channels. A cost function is proposed by employing linear constraint to the demixing vectors. The linear constraint is shown to be sufficient for avoiding trivial solution. The minimization of the cost function is performed using the Lagrangian method. Simulation results demonstrate the performance of the algorithm.