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1.
2月份的时候,我们就已经知道伦敦交响乐团(London Symphony Orchestra,简称LSO)要来中国演出,起初看到行程安排是北京、上海、香港,后来加上了天津和广州。在接到了这个消息以后,广州不少乐迷兴奋了好一阵子。之后票价出来了,是380到1880大元,广州只演一场,对比北京上海香港的分别两场,有些寒酸,但毕竟在3年前巴黎管弦乐团到访以后以,终于有机会再次听到世界一流乐团了,机会实在难得。  相似文献   

2.
非晶硅太阳能电池的新进展   总被引:1,自引:0,他引:1  
对非晶硅材料的物理性能及工艺优势进行了阐述,其中介绍了一种新型的刻划成图工艺,即等离子CVM,简单回顾了非晶硅太阳池的历史发展,分析了非晶硅太阳电池当前所存在的问题,提出了其发展的方向,其中,主要论述了叠层非晶硅太阳电池,并介绍了几种新型的非晶硅电池,最后,概括了非晶硅太阳电池的应用现状及前景。  相似文献   

3.
基于相关法的合成孔径雷达运动目标的参数估计   总被引:1,自引:0,他引:1  
本文针对合成孔径雷达运动目标的运动参数估计问题,将方位向频谱相关法用于运动目标的参数估计,本文详细探讨了频谱相关法,给出了相应的框图,在此基础上,利用自适应滤波的概念,引入了时域估计的方法,将两者在计算量进行了比较,并采用在原始数据中注入运动目标的方法,通过计算机模拟,给出了不同信噪比和不同运动速度下的参数估计曲线,将两方法进行了比较,得出了一些有参考意义的结论。  相似文献   

4.
文章在分析了电动机运行状况的基础上,根据电动机常见的故障特征,如相间接地;定子绕组开路、过负荷,失压,堵转、过热等,提出了基于ISPLSI及196系列单片机为核心的实用电动机保护方案,具有零序保护、负序电流保护,正序电流保护,过载保护,堵转保护,过热保护,失压保护等功能,在算法上进行了数学模型的建立和推导,在硬件,软件上进行了优化设计,特别是采用了在系统可编程逻辑器件(ISPLSI1032E),使装置具有简洁,稳定,速度快,抗干扰性好,保护功能强等特点。  相似文献   

5.
介绍某维修测试台编码显示器的设计及模块电路的应用,采用高集成化电路完成该维修测试台轴角编码显示的功能,不但缩小了体积,比用分离元器件设计的电路器件数减少了90%左右,且给电路的设计,加工,调试等带来了很大的方便,改善了电路的可维修性,进一步增强了电路的可靠性。  相似文献   

6.
介绍了基于硅的微型燃料电池的国内外研究动态,总结了微型燃料电池的研究成果,并对其制作方法中的关键技术进行了阐述。在此基础上,根据微通道的特性,分析了电极板上各种不同截面形状的气道对微型燃料电池性能的影响。当由气道决定的水力直径Dh由大变小时,在同样的实验条件下,电池性能开始逐渐变好,达到一个最佳值后,性能又逐渐下降。  相似文献   

7.
给定拓扑结构的网络的可靠性设计   总被引:6,自引:0,他引:6  
本文首先讨论了网络链路堵概率的加权平均值,提出了网络分配的一般准则,并在考虑了网络链路生存链路概率的因素后,提出了更一般的网络链路堵塞概率的加权平均值,以此为基础,分别讨论了网络在给定点的费用条件下,使得网络可靠性最大的网络设计问题,以及在给定网络可靠性指标的前提下,使得网络费用最小的网络设计问题。  相似文献   

8.
《家庭电子》2007,(9):127-127
记得刚刚大学毕业的那段日子,我失落、彷徨,像一头困兽整天在网上游荡。为了找工作,想为自己购置一部手机,于是出入于各大手机网站,直到有一天在论坛中发现了LGG650这款手机,让我眼前一亮。它大气的外表、出众的性价比都深深地吸引了我。我平生第一次对一件事情这么快就做出了决定,迫不及待地把手里的钞票变成了小G,当天晚上我兴奋得失眠了,这可是我毕业以后的第一个大手笔。  相似文献   

9.
余浩  丁炜 《数字通信》1998,25(4):20-23
首先介绍了局域网仿真的起因,定义和所提供的业务类型,然后了讨论了实现局域网仿真的关键技术,包括连接管理技术,地址解析LE-ARP技术,用户数据传输技术,最后,总结了局域网仿真的优缺点。  相似文献   

10.
《新潮电子》2005,(6):188-191
悠久的历史 传说古代的一位波斯国王爱吃葡萄,为了防止他人偷吃,他将采摘下来的葡萄藏在一个大陶罐里,并在上边写上“有毒”。数天后,一个妃子因对生活感到了厌倦,偷偷饮下了陶罐内的液体,结果,她非但没能结束自己的生命,反而感到异样兴奋。妃子把此事告诉了国王,国王试饮后也欣喜异常,于是他颁布了法令,专门征收成熟的葡萄,放在容器内压紧发酵,以便得到“毒液”——葡萄酒。  相似文献   

11.
DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.  相似文献   

12.
From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.  相似文献   

13.
The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.  相似文献   

14.
The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.  相似文献   

15.
Today, micro-system technology and the development of new MEMS (Micro-Electro-Mechanical Systems) are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.  相似文献   

16.
Waveguide multilayer optical card (WMOC) is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling & processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic (VB) language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.  相似文献   

17.
This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel's.  相似文献   

18.
It is a key problem to accurately calculate beam spots' center of measuring the warp by using a collimated laser. A new method, named double geometrical center method (DGCM), is put forward for the first time. In this method, a plane wave perpendicularly irradiates an aperture stop, and a charge couple device (CCD) is employed to receive the diffraction-beam spots, then the geometrical centers of the fast and the second diffraction-beam spots are calculated respectively, and their mean value is regarded as the center of datum beam. In face of such adverse instances as laser intension distributing defectively, part of the image being saturated, this method can still work well. What's more, this method can detect whether an unacceptable error exits in the courses of image receiving, processing and calculating. The experimental results indicate the precision of this method is high.  相似文献   

19.
The collinearly phase-matching condition of terahertz-wave generation via difference frequency mixed in GaAs and InP is theoretically studied. In collinear phase-matching, the optimum phase-matching wave hands of these two crystals are calculated. The optimum phase-matching wave bands in GaAs and lnP are 0.95-1.38μm and 0.7-0.96μm respectively. The influence of the wavelength choice of the pump wave on the coherent length in THz-wave tuning is also discussed. The influence of the temperature alteration on the phase-matching and the temperature tuning properties in GaAs crystal are calculated and analyzed. It can serve for the following experiments as a theoretical evidence and a reference as well.  相似文献   

20.
Composition dependence of bulk and surface phonon-polaritons in ternary mixed crystals are studied in the framework of the modified random-element-isodisplacement model and the Bom-Huang approximation. The numerical results for Several Ⅱ - Ⅵ and Ⅲ- Ⅴ compound systems are performed, and the polariton frequencies as functions of the compositions for ternary mixed crystals AlxGa1-xAs, GaPxAS1-x, ZnSxSe1-x, GaAsxSb1-x, GaxIn1-xP, and ZnxCd1-xS as examples are given and discussed. The results show that the dependence of the energies of two branches of bulk phonon-polaritons which have phonon-like characteristics, and surface phonon-polaritons on the compositions of ternary mixed crystals are nonlinear and different from those of the corresponding binary systems.  相似文献   

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