Chen Guobang

A separate two-stage pulse tube cooler working at liquid helium temperature

A novel 4 K separate two-stage pulse tube cooler (PTC) was designed and tested. The cooler consists of two separate pulse tube coolers, in which the cold end of the first stage regenerator is thermally connected with the middle part of the second regenerator. Compared to the traditional coupled multi-stage pulse tube cooler, the mutual interference between stages can be significantly eliminated. The lowest refrigeration temperature obtained at the first stage pulse tube was 13.8 K. This is a new record for single stage PTC. With two compressors and two rotary valves driving mode, the separate two-stage PTC obtained a refrigeration temperature of 2.5 K at the second stage. Cooling capacities of 508 mW at 4.2 K and 15 W at 37.5 K were achieved simultaneously. A one-compressor and one-rotary valve driving mode has been proposed to further simplify the structure of separate type PTC.

Study on Reaction Characteristics of Er3Ni Hydrogenation

Abstract In order to better understand the mechanism of the reaction characteristics of Er 3 Ni hydrogenation, a self-built hydrogen-adsorption experimental apparatus was used to study the effects of particle size, reaction temperature and pressure on the induction time of Er 3 Ni hydrogenation reaction and the hydrogen adsorption capacity, based on which the hydrogenation characteristics of Er 3 Ni were then discussed. The results show that activation has a great effect on hydrogen absorption capacity of Er 3 Ni. The influence of particle size of Er 3 Ni is mainly on the induction time. Lower reaction temperature needs longer induction time of accumulating energy to overcome the energy barrier of hydrogenation. The value x in Er 3 NiH x is insensitive to the reaction equilibrium pressure. Hydrides Er 3 NiH x reaches equilibrium at an extremely low pressure, about 10 kPa.