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The helium cryogenic system supplies supercritical helium cooling capacity at 4.5 K for the superconducting magnets in the EAST superconducting tokamak.Four low-temperature helium turbines are used in the 2 kW helium refrigeration system,and their performance and reliability are critical for the continuous operation of the tokamak.The turbines were made by the Helium Mechanics Company in Russia.The start-up process is very unstable,easily broken,and thus testing and improvements are needed.In this paper,we analyze the structure of the helium turbine,make improvements,and describe the testing process and results of the improved helium turbines.Some of the operational experiences during the start-up process and tests are also presented. 相似文献
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膨胀土(岩)处理是南水北调中线干线工程总干渠的关键技术问题之一。初设阶段,对膨胀土(岩)渠段采用了以放缓渠坡和对膨胀性渠床进行换填措施为主的处理方案。工程实施阶段,根据试验段的膨胀土试验情况,确定增设抗滑桩措施进行加强处理,弱膨胀土渠段采取适当加厚换填土,填方渠段包边厚度适当加厚,换填土采用水泥改性土的方案较为适宜。新增方案产生大量的设计变更,怎么样在"依法合规、实事求是、公平合理、风险共担"的原则下处理好抗滑桩变更成为重中之重。 相似文献
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田间试验结果表明,11%氧乐;酮乳油防治麦蚜,小麦白粉病,优于氧乐果对麦蚜的防效,对白粉病的防铲与三唑酮相当,并且具有用药成本低,劳动强度小,一次施药瘘治病虫害的优点,是防治麦田病虫的较好药剂。 相似文献
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An experimental method is presented to analyze the dynamic stability of the gas bearing for small cryogenic turbo-expanders. The rotation imbalance response and... 相似文献
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试验表明 :35 %一锄WP对移栽油菜田杂草具有较好的防效 ,70g/6 6 7m2 对禾本科草和阔叶草的株防效 ,药后 15~ 5 3天分别高达 97.2 2 %~ 10 0 %和 84 .4 1%~ 88.2 4 % ,显著高于对照药剂36 %广灭灵CS30 g/6 6 7m2 的防效 ,并且对移栽油菜具有较好的安全性 相似文献
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计算机科学及其应用技术在自然科学各领域中的应用和发展以及所取得的成就为世人瞩目,在我国的给排水专业领域里,计算机的应用进步较晚,落后于世界上发达国家的同类专业和国内某些其它专业,当前计算机正在进入一个以网络为中心的新的发展时期,如何更好的利用计算机及网络促进促进和服务于给排水行业是当代给排水工作者面前的一个新课题和长期任务。 相似文献
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Construction of a 2kW/4K Helium Refrigerator for HT—7U 总被引:2,自引:0,他引:2
Superconducting magnets of toroidal field (TF) and poloidal field(PF) of HT-7U tokamak are all made of NbTi/Cu Cable-in-Conduit Conductor (ClCC),and cooled with a forced flow supercritical helium of 3.8K.A helium refrigerator with an equivalent capacity of 2kW/r K will be constructed.This paper presents the design of the helium refrigerator process.The thermodynamics of the refrigeration cycle and the refrigerator equipments. 相似文献