共查询到20条相似文献,搜索用时 406 毫秒
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中国加入WTO短短几个月,在外面的人来看,整个电信行业好像风平浪静,可实际上,行业内的人士都清楚,这短短几个月相当于过去的几年。在这短短几个月内,电信行业过去久拖不决的几个老大难问题,都轻松地迎刃而解。什么原因?可以说以前是只有消费者一厢情愿的呼吁,而没有运营商自我变革的内因,所以正应了辩证法那句话,“内因是变化的根据,外因是变化的条件”,只有外因,没有内因,变革终究不能发生。而如今加入WTO给了运营商很大的刺激,运营商不变革不行了,所以内外条件相合,量变终于在瞬间转化成为了质变。所以我们说,WTO… 相似文献
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本文介绍了影响半导体异质外延晶片质量的主要原因,检测方法,几个典型测试结果。最后给出了几个外延晶片材料质量评估的参照标准。 相似文献
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介绍了一种灵活多用的32抽头模拟延迟线BAD32,分析了它的工作原理和应用中必须注意的几个问题,给出了几个典型应用实例。 相似文献
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文献[1~4]给出了通信密钥分散管理的几个方案。而经文献[5~7]分析研究,指出这几个方案并不是(k,n)门限方案。本文首先给出了判定不是(k,n)门限方案的简易方法,然后分析这几个方案不是(k,n)门限方案的原因,并对这几个方案给予修改,使得它们确实是(k,n)门限方案。最后对[8~10]给予讨论,指出它们存在的问题。此外还指出了其中一些方案其实是多密钥的(k,n)TCSSS。 相似文献
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Matlab在图像编码算法研究中的应用 总被引:1,自引:0,他引:1
介绍了matlab进行图像编码算法研究用到的几个函数及其在程度中的使用,并给出了数据结构转换的几个程序,由此可以构成一个算法研究的系统。 相似文献
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文章介绍了AD820、AD822和AD824运算放大器的主要性能指标及其特点,列举了几个应用例子,并且讨论了应用中几个有关问题。 相似文献
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本文首先对硅橡胶作了简单的介绍,然后详细叙述了几种常用硅橡胶的性能及用途,并列举了混合微电子技术中应用硅橡胶的几个实例,最后,提示了几点注意事项,以帮助读者合理地选用硅橡胶。 相似文献
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《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1969,57(7):1292-1293
It is shown that, in a given graph, the set of trees not containing a given branch can be obtained from the set of trees containing the given branch without duplications. Based on this, a simple derivation of Mayeda and Seshu's technique on generation of trees without duplications is given. 相似文献
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对于一个给定的网络图,可以确定对应的网络矩阵。同样,如果给定网络矩阵,也能够画出对应的网络图。本文讨论由基本割集矩阵求网络图的方法,该方法利用基本割集矩阵Q和降价关联矩阵A的关系,由Q得到A,进而画出对应的网络图。本文的讨论可供从事电路教学的教师参考。 相似文献
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《IEEE transactions on information theory / Professional Technical Group on Information Theory》1968,14(5):765-766
A sufficient condition involving a hypothesis of mean-square convergence is given for the convergence of discrimination information. A stronger condition requiring uniform convergence has already been given. An example is given which satisfies the mean-square convergence hypothesis but not the uniform convergence hypothesis. 相似文献
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Tables of the gain-area product of a circular aperture are given and explained. Particular attention is given to the realization of maximum gain over a given area with no constraints on aperture size, but with a simple in-phase aperture distribution; and with a given aperture size, using the same class of illumination function 相似文献
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A simplified Coates flow-graph technique, applied to the analysis of an arbitrary active network, is presented. Flow-graph representations of building blocks of active networks are given, which permit construction of the graph from the given network. A flow-graph formula for the sensitivity investigation is also given. 相似文献
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AnN -port loaded scatter is one havingN ports to which lumped impedance loads or a load network is connected. Methods are given to determine the characteristic modes of a loaded scatterer and for using them in a modal solution for electromagnetic scattering. A procedure is also given for resonating any given real port current, which makes that current the dominant mode of the loaded scatterer. The theory is formulated both in terms of open-circuit and short-circuit network parameters. A number of numerical examples are given for a wire triangle to illustrate the general theory. Computer programs are available for all procedures discussed. 相似文献
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激光熔凝加工中瞬时温度场及残余应力数值模拟 总被引:2,自引:0,他引:2
以激光熔凝表面强韧化处理为背景,应用空间弹塑性有限单元和高精度数值算法同时考虑材料组织性能的变化模拟工件的温度场及残余应力,研究激光熔凝加工中瞬时温度场及残余应力数值模拟,同时考虑相变潜热及相变塑性的影响,用算例验证了模型的正确性,给出了不同时刻温度场分布及残余应力分布。 相似文献
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《Microwave Theory and Techniques》1981,29(3):229-234
A procedure is given for obtaining the impedance transformer which will produce a prescribed pair of phasor reflection coefficients by transformation from a given pair of impedance states terminating the transformer. The transformer may be used in a general two-state reflection modulator: as a phase shifter with phase change at constant amplitude or as an amplitude modulator with level shift at constant or variable phase. The condition governing the reflection coefficients available from a given pair of impedance states is given. Examples and limitations are discussed. 相似文献