共查询到18条相似文献,搜索用时 62 毫秒
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由于高温超导材料的临界温度较高,可以运行在一个较宽的温度范围内,因此高温超导磁体被看作是稳定性较好的磁体,它在超导电力、超导磁体方面的应用占着日益重要的地位.YBCO带材作为第二代高温超导体的代表,近年来其生产工艺水平也得到了迅速发展和提高.磁体失超是影响超导磁体运行稳定性的重要问题之一.本文研究了YBCO单饼线圈在液氮环境中因由热扰动诱发的失超特性,设计了一套高温超导线圈在液氮浸泡下的失超测量系统,通过软件LABVIEW和数据采集卡对线圈的温度和电压进行采集和记录,测量YBCO单饼线圈在不同运行条件下的失超特性. 相似文献
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高温超导磁体临界电流磁矢量分析法准确地预测了BSCCO高温超导磁体的临界电流,为了进一步验证该方法预测YBCO高温超导磁体临界电流的准确性,文中作者用9.3m二代高温超导YBCO带材绕制了一个内径为70mm,外径为100mm,共35匝的单饼,测试了单饼5-15匝,15-25匝,25-35匝和5-35匝在77K下的临界电流,并用磁矢量分析法进行了仿真分析。通过对比发现,仿真分析和实验结果的误差在5%左右,最大误差是6.75%,最小误差是4.77%,验证了磁矢量分析法在预测YBCO高温超导磁体临界电流时的准确性。 相似文献
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付猷昆 《核工业西南物理研究院年报》2003,(1):113-114
近来膜超导体YBCO的长尺寸化取得了较大的进展,有望在不久的将来用这种下一代的高温超导体制成超导线圈。与用低温超导体材料绕制的线圈相比,高温超导线圈可以在较高的温度下运行且较难发生失超现象。即使这样,对高温超导体失超的研究和测量也是非常有必要的。特别是膜超导体由YBCO薄膜和Ni基金属基带(比如Hastelloy合金)组成,当导体失超时有较高的电阻率。 相似文献
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在实际的超导电力装置运行过程中,超导带材可能由于电力系统中诸如系统短路故障等各种动态过程,承受短路大电流、不平衡电流的冲击,以及由此而产生的电磁、机械应力、热量的作用而失超,因此,研究热冲击对超导材料性能的影响对超导电力装置失超保护非常重要.本文以第二代高温超导(YBCO)带材为样品,模拟实际超导电力装置中带材的绝热环境,通过外加电源对超导带材进行热冲击,研究YBCO带材在不同情况的热冲击条件下的失超过程以及带材温度和超导性能的变化.试验结果表明:对于美国Superpower公司生产的YBCO工程带材,瞬时温度超导300K后,带材的临界电流下降,瞬时温度超过500K,带材可能出现烧断现象. 相似文献
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YBCO线圈的交流损耗直接关系到YBCO设备的运行成本及稳定性。实现对YBCO线圈交流损耗的快速、准确测量,对于开展YBCO涂层导体的应用研究具有重要的意义。文中采用电测量法,在77K、零场和不同频率条件下,对YBCO线圈通以不同运行电流时产生的交流传输损耗进行测量。构建了YBCO线圈交流损耗的数值计算模型,对YBCO线圈交流损耗进行理论研究,最后将实验数据与理论计算结果进行比较,两者结果基本一致。可以发现,YBCO线圈在频率低于75Hz时,交流传输损耗随频率的增大而减小,当频率从75Hz增加到195Hz时,交流传输损耗随频率的增大而增加。 相似文献
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M. M. Bonch-Osmolovskii T. I. Galkina A. I. Golovashkin K. Yu. Dovydenko A. Yu. Klokov S. I. Krasnosvobodtsev S. R. Oktyabrskii E. G. Romanov 《Annalen der Physik》1993,505(4):330-334
The photoresponse of a YBaCuO/ZrO2 bolometric structure was measured under modulated (λ = 630 nm) and pulsed (τ ≈ 7 – 8 ns; λ = 337 nm) laser excitation. The shape of the measured photoresponse was interpreted by a thermal model; nevertheless, the pulse amplitude for vanishing YBaCuO film resistance was 5–6 times greater than predicted; the thermal boundary resistance RBd between YBaCuO and YSZ was evaluated ? 10?2 K × cm2/Watt, which is considerably larger than estimated theoretically for the similar situation of YBaCuO/MgO [5]. 相似文献
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A dilatometer, using the three terminal capacitance technique, suitable for measurement of linear thermal expansion of solids
in the temperature range 1.3–300 K is described. The dialtometer is designed such that the mounting system for the specimen
does not undergo any significant changes in dimensions when the specimen is heated. The apparatus, therefore, yields in principle
absolute values of α, the coefficient of linear thermal expansion. The performance of the apparatus has been checked by measurements
on copper in the temperature range of 77–300 K. Some preliminary results on the behaviour of α for Y1Ba2Cu3O6.9 compound in the vicinity of superconducting transition temperature,T
c are also described. The system can detect relative changes in length Δl/l
0 of about 10−8. Attempts are being made to improve the sensitivity. 相似文献
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为了保护臭氧层,用于生产聚氨酯泡沫的CFC-11发泡剂已经被淘汰,新开发的环境友好型聚氨酯泡沫用于低温设计时缺乏热物理性质数据的支持。文中介绍了开发的三套实验测试系统,以对热导率、线性膨胀系数和比热容这三大热物性在从室温到低温一个宽广的制冷及低温温度区间内进行测试。测试系统采用多项措施保证低温测试所需要的真空环境及漏热问题,保证了测试的顺利进行,以期提供制冷工程设计急需的低温热物性数据,并对泡沫的生产工艺进行优化。 相似文献
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The electrical resistivity of soft solder (Pb0.28Sn0.72) has been measured in the temperature range 4.2 K to 300 K. The ‘alloy’ becomes electrically superconducting at a temperature
of 6.9 K. Above this, in the entire temperature range, the resistivity could be described, apart from the residual resistivity,
by the weighted average of the resistivities of the individual constituents which are derived from the Bloch-Grüneisen relation.
The results are in accordance with the phase diagram, which shows a co-existence of two phases in almost the entire range
of concentration of the Pb-Sn binary system. It has been shown that the thermal conductivity data on soft solder as well as
on Pb0.7Sn0.3, both taken from literature, could be interpreted on the same basis, below and above the ‘superconducting transition temperature’.
Recent results on other Pb-Sn systems are discussed in the light of this interpretation. 相似文献
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《Current Applied Physics》2014,14(2):196-205
The thermal behavior of lithium ion battery during charge and discharge is investigated by a numerical simulation. The commercially available cylindrical 18650 battery is modeled in this study. Two different models are used. The porous electrode model is simulated to obtain the Li content inside the particles. The transient thermo-electric model is used to predict the temperature distribution inside the cell. The results suggest that the increase in temperature during discharge is higher than that during charge. The temperature difference between charge and discharge is decreased with increasing C-rates. At a rate of 1C, the discharge temperature increases with a waving region at the beginning, whereas the charge temperature increases until certain point and then decreases. The thermal behavior is closely related to the change in entropy and applied current. 相似文献