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本文阐述了感温光纤和光纤光栅火灾探测的基本原理,分析了拉曼感温光纤火灾报警系统、独立光纤光栅感温火灾探测系统以及全同光纤光栅感温火灾探测系统的工作原理及应用方式。 相似文献
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针对目前航空飞机修理厂对飞机环控系统流量调节活门修理后测试方法落后,误差大的状况,设计了飞机流量调节活门计算机辅助测试台。本文详细介绍了该测试台的组成、工作原理及特点。 相似文献
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模拟式线型感温电缆及其应用 总被引:1,自引:0,他引:1
文章通过与普通型感温电缆的比较,介绍了英国Alarmline^TM模拟式线型感温电缆系统结构、工作原理、优缺点以及在广州体育馆工程中的实际应用。 相似文献
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<正>我厂4M12-59/30型氧气压缩机的进排气活门原结构的活门座和活门片及缓冲片均为不锈钢,因活门座与活门片间为硬接触,在工作过程中不锈钢网状活门片在高频率往复运动中不断冲击活门座,活门片一般在使用2~3个月就会出现倒气或活门片断裂的现象,容易因活门片断裂而造成活门座、活塞、气缸的损伤或产生火花,造成火灾隐患,国内已有这类事故发生。 相似文献
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玻璃液体温度计具有结构简单、使用方便、价格低廉等优点,是目前应用最广泛的温度测量仪器之一,其原理是利用在透明玻璃感温泡和毛细管内的感温液体随温度的变化而热胀冷缩的作用来测量温度的。本文主要对玻璃液体温度计的正确选用及示值误差修正方法进行讨论。 相似文献
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用电子显微镜、能谱、扭转试验机、球柱润滑评定仪等对失效分油活门的表面磨损形貌、显微组织、化学成分等进行了分析,对分油活门的扭断力矩、工作油料的润滑性进行测试;对历年分油活门失效的现象、结论进行了统计分析;讨论了活门组件失效的现象、机理.结果表明,活门组件失效与多余物有关.针对分油活门组件抗污染能力不足,在工艺上进行了一系列的改进,如改进材料、结构、表面离子注入、放大组件的配合间隙等,并通过了300h的试车考核. 相似文献
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自从本刊1977年第5期发表《简易插入式光电高温计在高温盐浴炉中的应用》一文后,不少同志来函了解简易插入式光电高温计(以下称仪表)的原理和制作等问题。为此,本文进一步作如下补充。一、仪表的制作简易插入式光电高温计是利用全辐射感温器的壳体及光路,以硅光电池作感温元件改装而成。感温镜头前装有导光管插入高温盐浴炉中,以电子电位差计为二次仪表。图1为该仪 相似文献
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排气活门是航空发动机上的一个非常复杂和重要的零件。大家知道,排气活门是汽缸内热气经排气管通向大气的一个关卡。它的用途就是借活门的来回往复运动与汽门座相接触而开启及关闭汽缸的内腔的。因而活门的菌部在整个工作时间都被热气所包围,而活门的杆部在运动中与汽缸头上的导套发生磨损,同时杆部的顶端与摇臂滑输相接触(见图1)。 相似文献
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李应刚 《中国新技术新产品》2013,(21)
本文以贵州安龙与广西隆林两县的界河南盘江天生桥二级电站为研究案例,通过对天生桥二级电站#5、#6水轮发电机组进水口蝴蝶阀活门进行活门噪声振动测试、活门过流板件固有频率测试等试验,找出了裂纹原因的分析。 相似文献
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针对二元NiTi形状记忆合金在应用中所显示出的局限性,三元NiTi基形状记忆合金通过第三组元的加入,改善了二元NiTi形状记忆合金的某些性能,弥补了其在应用中的不足,降低了成本,进一步扩大了NiTi基形状记忆合金的应用范围,从而一直受到研究者的广泛关注.综述了三元NiTi基形状记忆合金的研究现状,总结了存在的不足:首先,对于合金体系还需要大量的量化研究,确定出不同应用条件下合金的有效成分范围是其实用化的基础;其次,合金制备过程熔炼介质对合金产生的影响等重视不够;同时,应用性能研究还有待加强,性能的长效性与稳定性是关键,这方面的研究还缺乏充分而有效的数据. 相似文献
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铁基形状记忆合金及其应用 总被引:10,自引:1,他引:9
铁基形状记忆合金是继镍钛基、铜基形状记忆合金之后的新型记忆合金。本文对铁基形状记忆合金的分类、记忆性能、记忆机制及应用进行了评述 ,并展望了其应用前景 相似文献
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Hu T Chu CL Wu SL Xin YC Lu J Chu PK 《Journal of nanoscience and nanotechnology》2011,11(12):10954-10957
To conduct grain refinement induced by plastic deformation, NiTi shape memory alloy is processed by surface mechanical attrition treatment. The process leads to surface nanocrystallization and consequently surface hardening. The cross sectional microhardness of the treated NiTi is measured and compared to those of annealed NiTi specimens with residual stress relaxation and recrystallization. Our results show that surface nanocrystallization induced by surface mechanical attrition treatment is an effective method to enhance the surface hardness and anti-wear properties of NiTi shape memory alloy for the biomedical application. 相似文献
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Mohammad H. Elahinia Mahdi Hashemi Majid Tabesh Sarit B. Bhaduri 《Progress in Materials Science》2012,57(5):911-946
NiTi is categorized as a shape memory alloy that found interesting applications in vast areas of engineering from aerospace to biomedical; the latter applications are due to its biocompatibility in addition to its unique properties. The unique properties such as shape memory and pseudoelasticity make NiTi an excellent candidate in many functional designs. However, the manufacturing and processing complications of this alloy pose impediments to widespread applications. This paper discusses challenges and opportunities in making NiTi parts for biomedical applications such as implants. To this end, common manufacturing processes for NiTi from casting and powder metallurgy to machining are discussed. Also, new opportunities in additive manufacturing processes such as laser and electron beam techniques towards making 3D components from NiTi are described. Finally, the challenges in heat treatment and shape-setting of NiTi parts in order to attain desired shape memory properties are reviewed. 相似文献
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N. Levintant 《Vacuum》2007,81(10):1283-1287
Experimental results of an accumulation and return strain behaviour of the modified surface of NiTi alloy, as well as mechanical and shape memory behaviour, are shown in this paper.Surface of equiatomic NiTi shape memory alloy (in martensitic form) has been modified by high-dose ion-implantation technique using nitrogen ion beam. The low-energy (65 keV) and following high doses have been used: 1×1017, 5×1017 and 1×1018 J/cm2. Correlation between subsurface layers elemental composition of NiTi alloy, microstructure and shape memory properties is shown. 相似文献
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NiTi合金由于其形状记忆效应、超弹性和低模量等优良性能在生物医学领域得到广泛应用。然而,在生理环境中镍离子释放会诱发毒性和炎性反应,因此需要对其进行表面改性。从表面氧化、表面涂层和表面接枝大分子等方面综述了近年来国内外NiTi合金表面改性的研究进展,评述了各种表面改性技术的优势和缺陷,指明了NiTi合金表面改性的未来发展趋势。 相似文献
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ABSTRACTThe two-way shape memory effect in NiTi shape memory alloys is identified according to the evolution of the apparent modulus of the martensite during mechanical cycling. The microstrain and texture index of the NiTi samples are evaluated with synchrotron data to relate the evolution to the changes in the NiTi microstructure caused by mechanical cycling. The results show that a progressive decrease in the apparent modulus of the martensite during load, together with an increase in the apparent modulus of the reoriented martensite, are a sign that the NiTi sample is developing the two-way memory effect by mechanical cycling. When the two moduli show the same value, the two-way shape memory effect is fully developed in the NiTi alloy.This paper is part of a thematic issue on Titanium. 相似文献