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中心螺管是超导托卡马克装置磁体系统的重要组成部分 ,在 HT- 7U中 ,中心螺管采用管装超导电缆绕制 ,线圈以脉冲方式运行。文中介绍了 HT- 7U中心螺管模型线圈实验中 ,失超信号检测系统的工作原理及失超信号特点。当磁体以脉冲方式运行时 ,失超信号检测系统为装置提供可靠的失超保护动作信号 ;还给出了有关的实验数据和检测系统记录的失超信号变化曲线。 相似文献
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EAST装置做为全超导托卡马克装置,其纵场和极向场线圈全部由超导磁体组成,所以进行安全,准确,有效的超导线圈的失超保护是装置安全运行的首要环节.由于等离子体电流的建立必须由极向场线圈系统提供极快速的磁通变化,随之产生较高的交流损耗使得极向场线圈很容易发生失超.如何对快速交变脉冲磁场下的超导线圈进行有效的失超检测,这在世界上也无先例可循.EAST装置的失超检测系统经过几十轮单饼超导线圈实验及多轮装置正式放电实验后逐步建立和完善起来,并已通过工程验收满足了装置实验运行要求.本文主要介绍了EAST装置失超检测系统的基本结构和检测原理,重点阐述了极向场超导磁体失超检测的设计方法及实验结果。 相似文献
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《低温与超导》2017,(4)
EAST是全超导托卡马克聚变装置,其极向场和纵场线圈全部采用超导磁体。一旦发生失超,失超保护系统用于确保超导磁体和引线的安全运行。诊断超导线圈电阻电压变化是最直观也是最快捷的技术解决途径,主要难点在于研制高精度的噪声抑制补偿设备,用于抑制实验过程中在诊断信号上产生的大量感应噪声。原先采用模拟电路设计的二次补偿设备存在技术缺陷;而基于DSP技术二次电压补偿设备软硬件结合,大大提高设备精度,通过上位机可以方便实现关键参数与算法更新,经过两年时间,达到初步设计指标,并在近期EAST实验中成功实现并行试运行,下一步升级改造正在进行中。文中主要介绍了数字式二次补偿系统设计思路、补偿原理、以及初步实验测试结果。 相似文献
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J. A. Catterall 《Contemporary Physics》2013,54(5):495-514
A short account is given of the characteristic properties of superconductors and the reasons for the importance of superconductivity in science and technology. The occurrence of the phenomenon in metals, alloys and chemical compounds is briefly discussed, with particular reference to those materials having the highest critical temperatures. The major part of the article is concerned with the applications of superconductivity in engineering, and attention is particularly devoted to materials for magnet construction, the various uses of superconducting magnets, and the other applications of superconductors such as power transmission cables, and transformers. Some forecasts are made regarding the probable developments in superconductivity in the next few years. 相似文献
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A rather general enhancement of superconductivity is demonstrated in a hybrid structure consisting of a submicron superconducting (SC) sample combined with an in-plane ferromagnet (FM). The superconducting state resists much higher applied magnetic fields for both perpendicular polarities, as the applied field is screened by the FM. In addition, FM induces (in the perpendicular direction to its moment) two opposite currents in the SC plane, under and aside the magnet, respectively. Because of the compensation effects, superconductivity persists up to higher applied currents. With increasing current, the sample undergoes SC-"resistive"-normal state transitions through a mixture of vortex-antivortex and phase-slip phenomena. 相似文献
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Coexistence of ferromagnetism and superconductivity in normal mental/superconductor/ferromagnet structures
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<正>We extend the Blonder,Tinkham and Klapwijk theory to the study of the inverse proximity effects in the normal mental/superconductor/ferromagnet structures.In the superconducting film,there are the gapless superconductivity and the spin-dependent density of states both within and without the energy gap.It indicates an appearance of the inverse-proximity-effect-induced ferromagnetism and a coexistence of ferromagnetism and superconductivity near the interface.The influence of exchange energy in the ferromagnet and barrier strength at the superconductor/ferromagnet interface on the inverse proximity effects is discussed. 相似文献
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中国科学院近代物理研究所正在进行国际首台45 GHz全铌三锡超导离子源FECR(Fourth Electron Cyclotron Resonance)磁体的研制,该离子源磁体线圈由六个铌三锡超导六极线圈和四个铌三锡超导螺线管线圈组成。由于单根超导线绕制异形六极线圈(非标准鞍型)技术难度大,且铌三锡超导性能对应力敏感,为了测试单个铌三锡六极线圈性能能否达到设计指标,基于铝合金壳层结构和Bladder-Key精确预紧技术,设计了镜像磁场约束结构。本工作主要阐述了运用ANSYS参数化设计编程对镜像磁场结构进行优化设计的过程和优化后的镜像磁场结构,确定了室温预应力大小,并给出了线圈经过室温预紧、冷却降温和加电励磁后的最大等效应力。进一步结合实际六极线圈制作公差(±0.1 mm),分析和评估了公差对镜像磁场结构中六极线圈预应力施加的影响。 相似文献
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《中国科学:物理学 力学 天文学(英文版)》2020,(8)
Magnetic Weyl semimetals(WSMs) with broken time-reversal symmetry(TRS) hosting topological band structures are expected to provide an ideal platform for investigating topological superconductivity and spintronics. However, the experimental verification of magnetic WSMs is very challenging. Very recently, the kagome magnet Co_3Sn_2S_2 was confirmed to be a magnetic WSM by both angle-resolved photoemission spectroscopy and scanning tunneling spectroscopy and consequently has become the focus of great attention. This paper reports a point-contact Andreev-reflection spectroscopy(PCARS) investigation on the(001) surface and the side surface of the Co_3Sn_2S_2 single crystals, respectively. The measurements from the sample's(001) and side surfaces provide experimental evidence for transport spin polarization in the Co_3Sn_2S_2 magnetic WSM. Furthermore, the superconducting proximity effect in the Co_3Sn_2S_2 single crystal is successfully detected. The point-contact spectra(PCS) along the in-plane direction cannot be well fitted by theoretical models based on s-wave pairing, indicating that possible triplet p-wave superconductivity may be triggered at the interface, which paves the way for the future exploration of the topological superconductivity and Majorana states in broken TRS WSMs. 相似文献
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新型超导体二硼化镁(MgB_2)基础研究及其应用展望 总被引:2,自引:0,他引:2
文章简要介绍了新型超导体二硼化镁的发现、研究进展和应用前景 .理论和实验都已经证明 ,二硼化镁的超导电性来源于电声子耦合 ,可以用具有S -波对称性波函数的BCS图像来描述 .然而在二硼化镁超导体中 ,人们发现有两个超导能隙 ,一个在 6meV ,另外一个在 2meV左右 ,它们同时在超导转变温度处打开 ,这给超导机理研究带来了一些新的内容 .在混合态物理方面 ,人们发现超导与正常态的边界线 (上临界磁场Hc2 )与磁通融化线(不可逆线Hirr)之间有很大的间隙 ,即使在绝对零度时也是如此 ,作者提出这可能是由于双能隙的结果或磁通物质的量子融化 .在应用方面 ,最有可能把它做成超导磁体 ,利用闭路循环制冷机制冷在 2 0K左右使用 ,这样极有可能取代现在医学上使用的核磁共振成像的液氦温度超导磁体 相似文献
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遗传算法具有很强的自适应性、鲁棒性和全局搜索能力,但其局部搜索能力相对较弱,计算后期易出现进化缓慢、过早收敛等问题,蚁群算法是近几年迅速发展起来的一种新的全局优化算法,具有正反馈机制,但是计算初期由于信息素差别小,初始收敛速度较慢.本文将这两种优化方法结合起来,充分发挥各自的优势,形成了遗传-蚁群混合算法,并选用测试函数对算法的优化性能作了对比计算,最后以高温超导匀场磁体为实际应用目标,以绕制磁体所用超导带长度为目标函数对磁体结构进行优化设计,优化方案比原始方案节省7.32%的超导带材用量. 相似文献