Owing to the influence of the atmospheric circulation with the different time and space, and the function of the dynamic and heat of the Qinghai Xizang Plateau, it is formed the “cold trough”(low temperature trough) in winter and “Thermal backbone”(high temperature backbone) in the east of China.

The Technology Demonstration of Portable Forced-Air Pre-cooling;

Effects of pre-cooling conditions on qualities of strawberries with different maturity levels;

Study on pre-cooling of fruit and vegetable in mini-cold storage;

Discussion of precooling operation of propylene jar at low temperature;

Analysis of cold air fluid field in precooling-box for pressure-difference precooling of tomatoes;

The effect of the different precooling and vase solution on preservation of Iris xiphium L. var. hybridum cv. Rosarlo after cutting;

To master the liquid helium transfer method correctly is of a great important sig-nificance in economy for reduction of the liquid helium precool amount, full use of the liquidhelium cool amount and increase of the transfer efficiency of liquid helium In this paper the construction and use demands of the liquid helium transfer tubes,liquidhelium precool and transfer methods are presented.

J - T loop is precooled by two - stage pulse tube cryocooler in order to obtain liquid helium temperature.