共查询到18条相似文献,搜索用时 78 毫秒
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随着大型低温真空泵、高低温超导器件、核磁共振成像仪、红外探测器、低温光电子学器件的迅速发展,以及作为传统蓄冷材料的铅(Pb)等有害物质的限制使用,对大冷量新型蓄冷材料G-M制冷机的发展提出了迫切的需要。文中主要介绍国内外大冷量G-M制冷机及新型磁性蓄冷材料的最新研究进展和应用情况,并提出了下一步的研究方向。 相似文献
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叙述了极小型低温制冷机系统的设计要求、设计计算、结构特点和测试结果,对影响制冷机的可靠性各类因素进行了分析,目前该制冷机与红外探测器组件的联试已取得成功,制冷机各项设计指标已满足组件要求。 相似文献
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Based on the evolution of the quantity of Sr in Pr0.63Dy0.37-xSrxMnO3 (x = 0.00 and x = 0.30) systems and the different heat treatments (500, 800 and 1300 °C), various physical changes are illustrated by these samples. X-ray diffraction patterns were carried out revealing that the heat temperature can affect the structure of the systems.Zero-Field-Cooled and Field-Cooled magnetizations revealed the appearance of different magnetic transitions; from the paramagnetic state to the antiferromagnetic one. Once increasing the temperature of heat up to 1300 °C and for x = 0.30, the system presents a ferromagnetic order at Curie temperature that is around 200 K. Magnetic hysteresis loops confirm the transitions presented by the magnetic measurements.The heating temperature affected also the evolution of the magnetic entropy change. All samples show an important increase in the data values of the maximum of the magnetic entropy change while augmenting the applied magnetic field. We note an important result that is the refrigerant capacity of the x = 0.30 sample heated at 1300 °C is 725% compared to that at 500 °C. 相似文献
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