中文摘要：

综述了空间用4 K温区预冷型JT制冷机方案及其相关的空间项目,研究表明该类型制冷机一般由斯特林或斯特林型脉管制冷机和JT制冷机组成,前者为后者提供预冷,后者通过节流效应降温获得4 K温区的制冷量。总结了制冷机的性能参数和系统结构,对比分析了该类型制冷机与GM/JT制冷机间存在的性能差距和关键技术差别,阐明了预冷温度和压力等参数对制冷机效率的影响,指出了当前该类型制冷机的改进空间和方案。

英文摘要：

The precooled JT cryocooler working at 4K were reviewed with their space applications. It shows that this kind of cryocoolers are usually composed of a Stirling（ST） or Stirling-type pulse-tube （STPT） eryocooler and a JT eryoeooler. The JT cryocooler can provide cooling power at 4K when it is precooled by a ST or STPT cryocooler. The published parameters and the common structure of the cryocoolers were sum- merized. The performance of the preeooled JT cryocoolers were compared with a GM/JT cryocooler, and the different technologies between them were pointed out. The effects of precooling temperature and pressure on the performance of the precooled JT cryocooler were analyzed. The analysis illustrates the key points to improve the performance of the precooled JT cryocoolers.