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故障现象:一台TOPCON单色显示器在联机时加电,工作指示灯亮,有高压启动的声音,开机数秒钟后,机内出现“吱吱”声,且显示器没有光栅(该类机在正常情况下联机才有光栅).故障分析:根据机内发出的“吱吱”叫声和工作指示灯亮这一现象,可以说明稳压电路基本正常,故障可能是行输出电路及行输出负载电路存在短路现象,从而引起电源负载过重而发出不正常的叫声. 相似文献
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结合第二相析出强化原理并采用基于饱和值调整法的工艺路径,使用计算软件辅助制定第二相强化真空渗碳淬火工艺,并对18CrNiMo7-6钢制圆片试样和齿轮试样进行了试验。分别测试了圆片试样与齿轮的表面硬度、淬硬层深度,并观测了圆片和齿轮试样的显微组织。结果表明,第二相强化渗碳工艺可导致在渗碳层中析出大量弥散细小且分布均匀的碳化物,其作为渗碳层中的第二相粒子,提高圆片试样表面硬度至840 HV左右,且高硬度层较深,硬度-层深曲线较为理想,可以应用在齿轮等传动部件以提高其表面硬度。 相似文献
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GB/T 50081—2002《普通混凝土力学性能试验方法》中规定:“采用标准养护的试件应在……温度为(20±2)℃,相对湿度为95%以上的标准养护室中养护。”可见,标准养护室温度的有效控制和温度的均匀度、波动度将直接影响我们对混凝土试件的正确评定。 相似文献
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A plasma-based stable,ultra-wideband electromagnetic (EM) wave absorber structure is studied in this paper for stealth applications.The stability is maintained by a multi-layer structure with several plasma layers and dielectric layers distributed alternately.The plasma in each plasma layer is designed to be uniform,whereas it has a discrete nonuniform distribution from the overall view of the structure.The nonuniform distribution of the plasma is the key to obtaining ultra-wideband wave absorption.A discrete Epstein distribution model is put forward to constrain the nonuniform electron density of the plasma layers,by which the wave absorption range is extended to the ultra-wideband.Then,the scattering matrix method (SMM) is employed to analyze the electromagnetic reflection and absorption of the absorber structure.In the simulation,the validation of the proposed structure and model in ultra-wideband EM wave absorption is first illustrated by comparing the nonuniform plasma model with the uniform case.Then,the influence of various parameters on the EM wave reflection of the plasma are simulated and analyzed in detail,verifying the EM wave absorption performance of the absorber.The proposed structure and model are expected to be superior in some realistic applications,such as supersonic aircraft. 相似文献
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利用真空低压渗碳软件对20CrMoH钢的渗碳过程进行模拟,并根据模拟输出在WZSTQ真空渗碳炉上进行了试验。在800 Pa压力和960 ℃温度下渗碳,保压25 s,对比渗碳有效硬化层深度优化工艺。结果表明,最佳渗碳时间为120 min。优化工艺后,试验测得有效硬化层深度与软件预测的深度偏差在+0.23 mm以内,满足设计要求。软件预测的有效硬化层深度更接近齿轮产品的实测深度,最小偏差为+0.10 mm。通过930 ℃下渗碳试验,对比表面碳含量,证明了软件预测表面碳含量为0.75%时,与实测值基本一致,最大偏差为-0.02%。 相似文献
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采用二位式温度调节仪对实验室的恒温箱和高温炉的炉温进行控制时,提出在不增加用户较大成本的情况下来改善炉温温度波动度、温度均匀性、温度偏差几种方法。 相似文献
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