高温超导电缆终端恒温器热负荷的计算与测定

电力电缆已被确认为高温超导技术产业化的重要项目之一。高温超导电缆终端是运行在低温的超导电缆芯向常温的高压母线过渡和致冷剂进出口的汇集组件,具有很高的技术含量。简单地介绍高温超导电缆终端恒温器的结构和功能,主要讨论终端恒温器热负荷的理论计算方法,并与试验测定进行比较。     

高温超导变压器关键技术

由于超导材料的无阻载流特性,其在超导电缆、超导限流器、超导变压器、超导储能、超导电机等超导电力装置中的应用引起人们极大兴趣。其中超导变压器具有体积小、重量轻、损耗低、无火灾隐患、无环境污染和低漏抗等特点。简要介绍了高温超导变压器基本结构,重点介绍了变压器研发过程中的关键技术问题,包括液氮和气氮低温绝缘特性、超导绕组损耗分析、电流引线设计、非金属低温容器设计等,为高温超导变压器的研发提供有用的参考。     

交流超导线交流损耗测量装置

本文介绍了用沸腾法测量超导线样品交流损耗的测量装置，测量时样品室完全浸没在液氦里，消除了背景热流所速来的测量误差，该装置最小分辨率可达１ｍＷ，量程为１－１００ｍＷ。氦流量通过量热流量变送器转换为电压信号，由计算机数据采集系统来测量。现已附加了背场，可测量在一定背场下的交流损耗值。     

一台低温穆斯堡尔装置

穆斯堡尔效应在材料科学领域中已获得相当广泛的应用,成为研究材料的微观结构、相变、磁性,氧化及腐蚀等的有力手段之一。在材料科学中,温度是很重要的,它与材料的组织、性能密切相关,因而很需要用以测量高温和低温区穆斯堡尔谱(简称M谱)的装置。本文介绍一种在77-300K范围内可任意变温及恒温的低温装置,它带有两个由Mylar膜制成的     

核技术测量用的可变温度恒温系统

整个恒温系统由恒温器、真空抽气系统和控制设备三部分组成。恒温器(见图1)是系统的主体,它主要由样品架(7),真空室,冷指内、外套(3、4),液氮瓶(2),插座(6、9),上盖(8),抽气口(10),加热器(5),冷指(1)和杜瓦瓶组成。样品架(图2)采用导热良好的轻金属制成,而且射线出射窗为两对穿孔,有利于减少射线的散射;在靠近出射孔的上、下两端对称位置处开有由两半圆槽构成的深孔,以放置测温元件铂电阻;样品架和冷指(无氧铜棒)之间由圆柱套筒内壁及端面与冷指的外壁及端面密接,进行热传导;用活动压板将样品固定在样品架上。真空室为不锈钢,其上的电接头为单芯和多芯柯伐接头,冷指外套为薄壁不锈钢管,它所包含的空间亦是真空。为了满足正电子寿命测量的要求,着重考虑了真空室顶盖(图3)的结构和形状,它被设计成扁平形,在样品架安装许可的条件下,尽量减小厚度,以缩短两探头之间的距离。由于加热器离顶盖距离不太大,当调节温度时,热辐射比较严重,导致盖壁温度显著上升,这将影响     

HT-7U超导托卡马克装置低温杜瓦的真空问题

分析了HT－7U大型全超导托卡马克装置低温杜瓦内的真空状况，对影响真空指标至关重要的磁体主机氦泄漏漏率作了计算，介绍了在试验杜瓦成功实现超导磁体正常运行的真空调试与检漏实践。     

Cryostat for production and fast ejection of deuterium filaments

A cryostat for production and fast ejection of filaments of solidified gas is described. It is to be used particularly for feeding deuterium filaments into centrifuges with which D₂ pellets are fired at high speed and repetition rate (> 500 m s^?1, > 1 Hz) into plasma devices, fusion reactors and the like. The cryostat consists of an extrusion part and a storage part whose temperatures can be idependently controlled. The extruded deuterium filament can thus be temperature conditioned for optimum mechanical strength for the large forced acceleration in the guiding channel of the centrifuge. The D₂ pellets thus accelerated have to be of a defined length, which means that the feeding method has to meet extremely high requirements as regards the starting, stopping and speed of the filaments to ensure the exact entry of the pellets. Feed rates of up to 3.5 m s^?1 have been demonstrated.     

High RF power tests of the first 1.3 GHz fundamental power coupler prototypes for the SHINE project

The Shanghai High Repetition Rate XFEL and Extreme Light Facility(SHINE) project will use 6001.3 GHz fundamental power couplers, which are modified based on TTF-Ⅲ power couplers, for continuous-wave operation with input power up to approximately 7 k W. The first batch of 20 sets of 1.3 GHz coupler prototypes was fabricated from three domestic manufacturers for the SHINE project. To better characterize the radio frequency conditioning phenomena for validating the performance of power couplers, a ...     

Interfacing small closed-cycle refrigerators to liquid helium cryostats

Several different means of connecting small closed cycle refrigerators to liquid helium cryostats for the purpose of reliquefying the boiloff or reducing the boiloff rate are described. Interface principles which enhance the reliability and serviceability are presented. Most of the interfaces which are described permit the refrigerator to be serviced while maintaining liquid helium in the cryostat.     

Helium-4 isotopic purification without a superleak

We report the successful operation of a He⁴ isotopic purification cryostat which depends for its operation solely on the phenomenon of superfluid heat flush. The product He³ content was determined as being less than 3 × 10^?11.