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故障模式与失效分析是一种防患未然的可靠性管理技术,是生产过程中一项事前预防的分析手段.实验室仪器管理导入故障模式与失效分析方法,实现降低仪器维护使用成本、缩短故障停机时间延长仪器使用寿命、提高生产效率等预定目标. 相似文献
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本文介绍海燕牌CS51E-7A-R型彩电出现的几例对比度故障的检修过程,供同行参考。例1.故障现象:收看中图像突然变成浮雕状、隐隐约约,但伴音正常,主机面板上除对比度旋钮调节无效外,其它调节及遥控器的控制均正常。分析检修:该机型遥控发射器上没有设置对比度调节功能,对比度控制安装于主机面板操作盒内,与帧同步旋钮并排于盒的左端。试调节对比度旋钮,并仔细观察图像变化,发现对比度稍有改变,但不明显。该机主板系东芝两片(TA7680AP和TA7698AP)机,按照TA7698AP的电气参数,对比 相似文献
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(一) 日立CTP-237D型故障现象开机工作正常,不知何时出现回扫线,光栅变暗,只有彩色信号,过一会儿能自动恢复正常,但又说不定何时会再出现故障。检查分析正常工作时,一切都正常,电路板受振也无变化,说明故障原因并不是虚焊或元件松动。有故障时,亮度调节失效,对比度调节对亮度有一点影响,色度调节有明显变化且影响亮度,无色信号(关掉 相似文献
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当今时代,自动化控制设备及电子仪器仪表在各个行业已得到广泛应用。这些设备中均有印制电路板。电路板出现故障,会造成设备不能正常运行。大多数情况下,电路板的故障往往由某一个或几个元件的功能失效所引起,只要找到故障元件并予以更换,故障即可排除。但在实际工作中,一方面由于大多数设备(尤其是进口设备)不提供电路原理图,或者是电路图过于复杂,使得维修工作难以在短期内排除故障。另一 相似文献
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笔者日前检修牡丹54F1P和高路华TC2118W彩电各一台,故障均为伴音正常,无图像,满屏黄光栅或黄绿光栅,有字符显示,若将对比度加大仔细观察,在字符笔画中有活动图像,满屏有不明显的回扫线,其它正常。故障分析首先怀疑图像通道有问题,但断开CPU第(23)、(24)脚后,图像恢复正常,说明图像通道无问题。然后检测CPU和存储器部分。牡丹54F1P彩电(下称牡丹机)和高路华TC2118W彩 相似文献
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基于红外图像和可见光图像在有雾天气下退化过程中的相似性,可以使用大气散射模型对红外图像进行图像复原.但是图像在去雾复原处理后常常会有对比度低,细节不明显的特点,不利于人眼直接观察.针对这一情况,使用Retinex对去雾后的图像进行对比度增强.经过这两个算法处理后可以提高红外图像的对比度,突出其细节,提高其信噪比,并且具有良好的视觉效果.对算法的改进可以在计算处理速度和算法处理的效果上找到一个平衡点,为后期的嵌入式平台实现实时的视频去雾打下基础. 相似文献
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PROSAT(百胜)-2100S型DVB卫星数字接收机知名度较高,在边远的乡、镇、场占有量很大,通过近10年的使用其故障明显增多,特别是开关电源电路故障率较高.由于该机型未附电路图,笔者用一台正常PROSAT(百胜)-2100S型数字机作参考,已修复数台类似机型故障,现将该机型通病故障介绍给基层同行参考. 相似文献
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The article describes a model representation of radar probing data in form of a mixture of background and target samples, which is the sum of two random variables with very different parameters. For model development we research the behavior of the central moments of the distribution mix without assuming the distribution law form. An example it is described the detection of the signal at the output of compression system of chirp ionosonde. 相似文献
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解决IP网QoS问题是目前通信领域的研究热点之一.虽然研究已经取得了一定的进展,但人们对于IP 网QoS本身的含义及相关的问题还有着不同的理解.本文将从IP网QoS的定义入手讨论相关的一些问题以及解决IP网QoS问题所做的各种努力. 相似文献
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《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1968,56(6):1024-1032
Assuming that visual responses are due to the action of particles on the membrane of the visual cells, the stochastic variability of the response should be a function of the number of particles producing it. Quantitative predictions can be made with the aid of a model proposed in previous articles. It is found that responses produced in visual cells of Limulus by absorption of a single photon have the stochastic properties which would be expected if the response to one photon were brought about by 25 particles. It is concluded from this that the processes leading to visual responses produce multiplication of particles. The effects of temperature and of metabolic poisons suggest that these processes are of chemical nature. 相似文献
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By means of exact conformal mapping method we have defined character of dependence of squares amounts of angular part of film
element on angled part dimension. We propose relations, approximating obtained dependence. Calculation results and experimental
researches of large-scale models are represented. 相似文献
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Moshrefzadeh R.S. Radcliffe M.D. Lee T.C. Mohapatra S.K. 《Lightwave Technology, Journal of》1992,10(4):420-425
The temperature dependence of refractive index of polymer films was determined for a number of slab waveguides by a grating coupling method. This dependence was examined as a function of parameters such as molecular weight and glass transition temperature of the polymer. Temperature-induced changes in N TE-N TM , N being the effective index, were studied systematically for different slab waveguide compositions. It is shown that with proper device design and choice of polymeric materials, thermal effects can be reduced 相似文献
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A. M. Emel’yanov 《Semiconductors》2010,44(9):1134-1139
A method for analyzing the luminescence spectra of semiconductors is suggested. The method is based on differentiation of
the spectra. The potentialities of the method are demonstrated for luminescence in the region of the fundamental absorption
edge of Si and SiGe alloy single crystals. The method is superior in accuracy to previously known luminescence methods of
determining the band gap of indirect-gap semiconductors and practically insensitive to different conditions of outputting
radiation from the sample. 相似文献
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“计算机组成原理”设计性实践教学模式研究 总被引:1,自引:0,他引:1
本文阐述了"计算机组成原理"设计性实验教学的重要性,对设计性实验教学的目的和基本特征进行了归纳,对"计算机组成原理"设计性实验教学的现状进行了调查,对存在的问题进行了较深入的分析;在此基础上.对组成原理设计性实验的教学模式进行了研究,对设计性实验的体系进行了初步设计,并对"计算机组成原理"设计性实验的实施方法进行了探讨. 相似文献