The intelsat VIII/VIIIA generation of global communication satellites

Developed originally to meet increased demand forecast for C-band capacity in the Pacific Ocean Region (POR), this latest generation of INTELSAT satellites is planned to be operated in a number of traditional and new roles. To date INTELSAT has bought four INTELSAT VIII spacecraft for Pacific, Indian and Atlantic Ocean regions and two modified VIII-A to meet the specific Landmass requirements for the rapidly expanding Asia-Pacific and pan-American market. The VIII spacecraft, using Martin Marietta Astro Space's GS7000 bus has sufficient power and payload carrying capability that it can accommodate a wide variety of services. A new feature for INTELSAT is the inclusion of arcjet propulsion which has the potential for long lifetime while needing only half of the fuel requirement of conventional thrusters. This new high power satellite will form a key part of the INTELSAT global network through to the year 2010 and complement the INTELSAT VII and VIIA series.     

A condensed orbital history of intelsat satellites

A condensed orbital history, from mid-1965 to mid-1983, of the satellites in the INTELSAT system is presented in the form of a chart; this shows both the operational duties which the satellites performed and the occurrence of incidents which affected their performance in orbit.     

星载GPS接收机的可见星预测方法

GPS接收机在低轨卫星上有广泛的应用。事先预测可见GPS卫星有助于接收机快速捕获。地面接收机直接取仰角大于的GPS卫星为可见卫星,这一判决方法不适用于星载GPS接收机。根据GPS卫星天线覆盖范围,提出了一种对轨道高度分段讨论的基于仰角的可见卫星判决方法。通过MATLAB和STK仿真得到这一方法的平均预测正确率和召回率都大于93%。因此,这种方法适用于不同低轨轨道高度、不同航天任务的星载GPS接收机。     

电力通信综合数据网市县互联优化方案

针对某市综合数据网市县互联链路现状,文章分析了目前市县互联链路存在的问题,阐述了优化原则,重点探讨并制定了市县骨干综合数据网互联优化方案。在实际应用中证明了这一方案的可行性。     

An LCSD & La Raza Microhistory: The Latina/o Communication Studies Division & La Raza Caucus of the National Communication Association

For many members of the National Communication Association (NCA), the La Raza Caucus and the Latina/o Communication Studies Division perhaps always have existed. These units have been options for reviewing and submitting papers, exploring leadership opportunities and finding community within a large professional academic organization (NCA). It is more accurate, however, to say that the La Raza Caucus (hereafter, “LRC” or “the Caucus”) and the Latina/o Communication Studies Division (hereafter, “LCSD” or “the Division”) are recent developments. By the NCA Centennial, the LRC has not yet reached its 25th anniversary, and the LSCD will be in its 17th year.¹[1] The Division was approved by the National Communication Association in 1997. It might be tempting to argue that the creation of both units reflects the changing demographics in the U.S. that show tremendous increases in the Latina/o population. It also might be tempting to argue that the appearance of these units is evidence of an oversized NCA. (We often interpret complaints that “NCA is just too big” as a coded way of saying there are too many people of color in the organization.) Understanding the appearance of these units requires a more complex reading. In our Microhistory of the La Raza Caucus and the Latina/o Communication Studies Division, we place the origins and growth within two contexts: (1) publication trends in communication journals and (2) the professional development needs of members. The story of these units is a story of creating a self-determined space within a large and significant academic organization where ethnic identities gain expression, where geographic orientations are more north–south than east–west, and where there is a high degree of collective self-consciousness regarding what our scholarly activity means. In this essay, we describe the formation of the LRC and the LCSD, assess the professional needs that are met for members, and chart the direction for future studies and involvement in communication.     

含RS-232接口的I/O板卡的开发

从硬件构成及软件设计方面介绍一种含RS - 2 32接口的抗干扰性能良好的I O板卡 ,通过制定相应的通讯协议 ,上位机能够通过串口对本卡的所有资源进行读入与控制 ,该卡可直接用于要求数据传输速率比较高的工业现场控制系统     

2.5 Gbit/s光孤子的产生及外调制

采用半导体的增益开关法成功地产生了２．５Ｇｂｉｔ／ｓ的孤子光脉冲并对其进行了外调制。对经过调制的孤子光脉冲进行了检测，分析了实验原理及结果。     

非线性光学产生VUV／XUV相干辐射的发展和研究

本文对近年来非线性光学效应产生VUV/XUV相干辐射的理论和实验进展进行了概括和总结,作者首先对该方面工作的理论和实验背景进行了回顾,然后重点阐述了各种产生VUV/XUV相干辐射的方法,如金属蒸汽中的双光子共振四波混频,惰性气体中的非共振和共振四波混频以及强激光场下的高次谐波过程等,最后本文简要地讨论了非线性光学效应产生VUV/XUV应用,并对本工作的发展前景进行了展望。     

The separation of generation lifetimes of Si and SiGe using capacitance-transient measurements on MOS capacitors formed by plasma anodisation of Si:Si0.9Ge0.1:Si substrates

A simple technique leading to the measurement of minority carrier lifetimes of UHV compatible LPCVD Si and SiGe by C–t depth profiling of Metal:Oxide:Si:SiGe:Si structures is reported. A high quality gate oxide is realised by low temperature (<100°C) plasma anodisation thereby reducing any oxidation effects on the underlying epitaxial layer quality. Capacitance response times were observed for an impurity concentration of 2.5×10¹⁷ cm⁻³, giving rise to generation lifetimes of the Si and Si_0.9Ge_0.1 of >0.55 and 2.6 μs respectively, reflective of very high quality epitaxial semiconductor material.