中国的三种非同步轨道卫星移动通信系统星座方案

本文介绍基于我国的三种非同步轨道卫星移动通信系统星座方案：低、中轨系统各有２４和１８颗星，轨道高度分别为１３２６和８０３５ｋｍ，两系统各以５°和３０°的仰角对我国的覆盖率为９９．７８％和９９．９６％；椭圆轨道系统１２颗星，近、远地点分别为４２７和２９０６ｋｍ，以７°和１５°仰角对我国北纬２０°以上地区覆盖率分别为９７．９０％和８９．６１％，若增加４颗中轨卫星，以１５°仰角对我国的覆盖率为９９．９９％。     

The relation between luminous properties and oxygen content inZnS:TbOF thin-film electroluminescent devices fabricated byradio-frequency magnetron sputtering method

The purpose of this paper is to study the relationship between the oxygen concentration and brightness degradation in ZnS:TbOF green thin-film electroluminescent (EL) devices. The characteristics including crystallinity, optical, and electrical properties were discussed. The brightness-voltage (B-V) measurement results shelved that with higher oxygen-content in ZnS:TbOF phosphor layer, lower brightness was measured. It was consistent with the poor crystallinity, worse photoluminescent intensity, and easier to get moisture in the oxygen-rich (O/Tb>1) phosphor film. Furthermore, deep level transient spectroscopy (DLTS) measurements identified that when the O/Tb ratio was greater than 1, the oxygen-related deep hole traps E_H1 and/or E_H2 could be detected in the ZnS:TbOF phosphor layer. These E _H1 and/or E_H2 traps were believed to be the main killers for the brightness of the device since they capture most of the holes from the generated electron-hole pairs. This evidence strongly supports that the modified energy transfer model is more dominant than direct impact excitation during the luminescent process     

二阶A型Cooper变换的增强型

对二阶Ａ型Ｃｏｏｐｅｒ变换进行增强，放宽可用性条件，并证明了其正确性，最后举例说明其应用。     

试论企业人格化管理的力量因素

论述了影响企业人格化管理的力量因素，并指出制度纪律是其保障因素，道德规范是其自律因素，理想目标是其进取因素。     

Mass transfer kinetics of neodymium(III) extraction by calix[4]arene carboxylic acid using a constant interfacial area cell with laminar flow

BACKGROUND: Thermodynamics and kinetics data are both important to explain the extraction property. In order to develop a novel separation technology superior to current extraction systems, many promising extractants have been developed including calixarene carboxylic acids. The extraction thermodynamics behavior of calix[4]arene carboxylic acids has been reported extensively. In this study, the mass transfer kinetics of neodymium(III) and the interfacial behavior of calix[4]arene carboxylic acid were investigated. RESULTS: The rate constant (K_ao) becomes constant when the stirring speed was controlled between 250 rpm and 400 rpm. The activation energy (E_a) was calculated to be 21·41 kJ mol^?1 or 88·17 kJ mol^?1 (dependent on temperature) from the slope of log K_ao against 1000/T. The linear relationship between the specific area and the extraction rate is the characteristic of an interfacial reaction control. The minimum bulk concentration of the extractant necessary to saturate the interface (C_min) is lower than 4·19 × 10^?4 mol L^?1. CONCLUSION: The effect of stirring speed, temperature, and species concentration on the extraction rate demonstrates that the extraction regime depends on the extraction conditions. The chemical reaction control governs the extraction regime at temperatures below 303 K and a mixed control regime occurs when the temperature is between 303 K and 318 K. The probable locale for the chemical reaction is at the liquid–liquid interface and the rate equation is deduced to be: ? d[Nd³⁺]_(a)/dt = k_f[Nd³⁺]_(a)[H₄A]_(o)^0·727[H⁺]_(a)^?0·978. The rate‐controlling step was suggested by the analysis of the experimental results. Copyright © 2008 Society of Chemical Industry     

以不同PAN系炭纤维布制备燃料电池气体扩散层之研究

采用石墨化PAN系炭纤维布制备了高分子电解质燃料电池气体扩散层。通过电学实验、X-ray绕射与元素分析考察了所制气体扩散层的性能。结果表明：随热处理温度的升高，气体扩散层的电阻率降低，L2增加，d（x）2减小。高温处理后的炭纤维布作为高分子电解质燃料电池气体扩散层显示了较高的电池效能。     

自由口通信模式下计算机读写PLC存储区的程序设计

本文介绍了在自由口通信模式下，用计算机读写S7—200PLC存储区内相邻的多个字节数据的通信程序设计方法，程序设计中采用了多种可靠性措施。     

A digital secure image communication scheme based on the chaotic Chebyshev map

In this paper, a simple image secure communication scheme based on the chaotic Chebyshev map and chaos synchronization is proposed. The scheme relies on the excellent correlation property of chaotic sequences, which is very desirable for secure image communication. The results obtained by computer simulation indicate that the transmitted source image can be correctly and reliably recovered using the proposed scheme, even through a noisy channel. Notably, the scheme possesses relatively high security and can be easily implemented. Moreover, the quality of the recovered image is satisfactory, quantified by such common criteria as the bit‐error rate performance. Copyright © 2004 John Wiley & Sons, Ltd.     

Dreamweaver UltraDev环境下实现数据库的动态链接

简要论述了如何在Dreamweaver UltraDev环境下实现对已有的Access或Excel数据库的动态链接的操作。在Dreamweaver UltraDev环境下，实现对企业、事业单位原有Access或Excel数据库的动态链接，可以在很短的时间内开发出符合单位实际情况的信息管理系统，并且可以使这类已经创建好的数据信息，不加任何修改地与外部进行交流，实现资源共享。将此系统以主页的形式链入Internet，可以实现开放式管理体系。     

稀土元素的分离技术

对目前稀土元素分离过程中几种常用的分离技术进行了综述，使用得较多的仍然是溶剂萃取法和离子交换法，而且新方法也在不断地出现。