共查询到20条相似文献,搜索用时 125 毫秒
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本文叙述了660MW中间再热机组强制循环汽包炉的炉本体采用盐酸清洗、采用磷酸和多聚磷酸盐进行漂洗钝化的清洗工艺方法。其特点在于:为减缓金属腐蚀,必需严格控制清洗工艺配方。通过缓蚀剂对比小型试验探索出:在酸洗配方和水冲洗过程中,添加适量的异抗坏血酸钠还原剂可以抑制三价铁离子对金属的腐蚀,并可避免因水冲洗时间过长而产生二次锈蚀。该工艺实际应用后效果良好,金属腐蚀速率及腐蚀总量均显著小于《火力发电厂锅炉化学清洗导则》(DL/T794—2001)所规定的标准。该工艺还探索出:在酸洗和酸洗后的冲洗水中添加异抗坏血酸钠后,能够有效抑制三价铁离子的腐蚀危害,并减少二次锈蚀的产生。 相似文献
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介绍了几种常用的晶圆金属铝膜腐蚀工艺,并详细讲解了全自动单晶圆铝腐蚀清洗机采用第四种工艺配方进行金属铝膜腐蚀清洗的工艺过程。同时,简单介绍了为提高腐蚀清洗效果而设计的两套子系统的工作原理。 相似文献
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12Cr2MoWVTiB钢(简称102钢)是我国自己研究的多元低合金耐热钢,它取代了奥氏体高合金钢用来制造发电机组的高压锅炉再热器和过热器。102钢最早投入工业性应用已超过十万小时的设计寿命,它长期工作在594℃的当量温度、49MPa的压力和燃烧煤的烟气条件下,以至发生管子爆破事故,造成经济损失。本文通过对硫、氧等元素在102钢管壁内分布形态的研究,揭示该钢管被烟气等介质高温腐蚀的特征,对研究失效机理有着重要的参考作用。 相似文献
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免清洗工艺是针对原先采用的传统清洗工艺而言的,是建立在保证原有品质要求的基础上简化工艺流程的一种先进技术。本文详细对比分析了五种配方的免清洗助焊剂的助焊性、可靠性、对印制板的污染度,同时阐述了相关的涂敷工艺、焊接设备、工艺参数、工艺准备和工艺管理等。 相似文献
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针对带铝件的印制电路组件清洗后,铝件腐蚀的问题,探讨了各种清洗剂清洗的效果。结果表明:当清洗溶液φ(A)∶φ(B)为1∶(5~7),清洗剂体积分数6%~10%,温度50~55℃,时间10~15 min,采用KO2000清洗设备清洗,能同时解决铝件腐蚀问题及清洁度达到技术指标要求,清洁度≤1.55μg/cm2。适合带铝件的印制电路组件敷形涂覆前的清洗。 相似文献
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采用纳秒脉冲激光器对TC4钛合金表面的氧化膜及油污进行激光清洗,研究了扫描速度对清洗后试样表面形貌、成分、元素含量及价态的影响规律,并分析了扫描速度对表面粗糙度、硬度和耐腐蚀性能的影响。结果表明:当扫描速度为500 mm/s时,激光对基体的损伤大且会发生热氧化,表面形成TiO,O含量较高。随着扫描速度由3000 mm/s增加至10000 mm/s,表面逐渐变得光滑平整,O含量先降低后升高,Ti含量则先升高后降低。当扫描速度为9000 mm/s时,表面Ti含量(质量分数)达到最大值84.24%,O含量(质量分数)降至最小值4.54%,且粗糙度(Ra)最低约为0.907μm,清洗效果最佳。扫描速度的增加使清洗后表面的粗糙度先升高后降低。此外,激光清洗可使TC4钛合金表面的硬度和耐腐蚀性能有所提高。 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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罗晓羽 《信息技术与标准化》2008,(6):37-39
论述了推进电子行业标准制修订项目计划管理信息化的必要性.并提出了具体措施;详细介绍了电子行业标准制修订项目计划管理数据库的设计思路和实现方法.阐述了对后续工作的几点思考. 相似文献
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对影响镍镀层内应力的因素做了介绍和分析,提出了对收缩应力的一种解释,提供了排除这些因素影响的方法,指出重视镀液的管理是减少各种影响内应力因素的主要办法。 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