Pulse-Tube Dilution Refrigeration below 10 mK for Astrophysics

Astroparticle bolometric detectors often rely on the use of dilution refrigerators providing a large cooling power at millikelvin temperatures. Conventional machines, however, need a systematic supply of cryogenic fluids, complicating and making more expensive their operation, particularly in underground laboratories. We describe here novel cryogen-free dilution units, able to cool down large detectors to millikelvin temperatures, and where cooling and warming times have been optimised.      

Comparison of two models of a double inlet miniature pulse tube refrigerator: Part B electrical analogy

The design of a double inlet pulse tube refrigerator is investigated by means of an analogy with an electric circuit. The results obtained are compared with both those of the thermodynamic model (Part A) and experiments. The basic formulation of equivalent electronic components is discussed and a few improvements are proposed for adjusting the theoretical expressions of the electric impedance concerning the capillaries and the regenerator. Then additional effects such as pressure drops due to geometrical singularities are taken into account considering the different internal flow regimes that may occur. Besides a simplified formulation for the regenerator efficiency is deduced from considerations on its harmonic functioning. In this analysis, the emphasis concerns principally the design of miniature cryocoolers dedicated to electronic applications. Those models are applied to a commercial miniature refrigerator. A discussion of their relevance is achieved and a few suggestions on the refrigerator design are proposed in order to improve the cooling production.     

Investigations on triple fluid vapour absorption refrigerator

This Paper deals with theoretical and experimental investigations on the triple fluid vapour absorption refrigerator (TFVAR) in relation to the gas circuit, thermo-siphon and inert gas charge pressure. The charges of the various fluids were estimated. Helium seems to be a better inert gas than hydrogen. A compact absorber design is proposed.     

家用冰箱使用功能之本土化设计初探

通过将现有冰箱所具有的功能与具体人群的实际需求进行比较,从而找出其中的不切合点,对该产品引进和继承的同时,对其不适应的部分进行改进,使之真正适应具体人群的需要,体现家用冰箱使用功能的本土化。     

Production Of Ozone in an Electrical Discharge Using Inert Gases as Catalysts

The catalytic role of using inert gases to increase the efficiency and lower the power cost of producing ozone (O₃) from high purity oxygen (O₂) in a process incorporating an electrical discharge is demonstrated. Three inert gases (Ar, Ne, He) and N₂ are individually mixed with O₂ and the results presented. The increase in ozone production is partially attributed to the increase in electron density provided by the ionization of the inert gas in the discharge.     

Helium Adsorption on Lithium Substrates

We have developed a cryogenic pulsed laser deposition (PLD) system to deposit lithium films onto a quartz crystal microbalance (QCM) at 4 K. Adsorption isotherms of ⁴He on lithium were measured in the temperature range between 1.42 K and 2.5 K. The isotherms are qualitatively different from isotherms on strong substrates such as gold and weak substrates such as cesium. There is no evidence of the formation of solid-like layers of helium, and the helium coverage is approximately linear in the pressure over a wide range. By measuring the low coverage slope of the isotherms, the binding energy of helium to lithium was found to be approximately −13.6 K. For lithium substrates less than approximately 100 layers thick, the chemical potential at which the superfluid transition was observed was surprisingly sensitive to the details of lithium deposition. This work was supported by NSF grant DMR 0509685.     

（πR）最大时卡诺制冷机的利润率和制冷率

将利润率与制冷率结合在一齐，并以（πR）为目标函数，讨论了卡诺制冷机综合性能的优化，导出了（πR）最大时内可逆卡诺冷机的利润率和制冷率，所得结果对实践有一定的指导意义和参考价值。     

Comparison of two models of a double inlet miniature pulse tube refrigerator: Part A thermodynamics

The cooling of electronic components is of great interest to improve their capabilities, especially for CMOS components or infrared sensors. The purpose of this paper is to present the design and the optimization of a miniature double inlet pulse tube refrigerator (DIPTR) dedicated to such applications. Special precautions have to be considered in modeling the global functioning of small scale DIPTR systems and also in estimating the net cooling power. In fact, thermal gradients are greater than those observed in normal scale systems, and moreover, because of the small dimensions of ducts (diameter), the pulse tube cannot be assumed to be adiabatic. Hence thermal heat conduction phenomena must be considered. Besides dead volumes introduced by junctions and capillaries cannot be neglected any more in front of the volume of the gas tube itself. The hydrodynamic and thermal behaviors of the cooler are predicted by means of two different approaches: a classical thermodynamic model and a model based on an electrical analogy. The results of these analysis are tested and criticized by comparing them with experimental data obtained on a small commercial pulse tube refrigerator.     

环烷基润滑油临氢降凝生产全封闭冷冻机油工艺研究

新疆环烷基常二线、减二线润滑油馏分采用ＲＤＷ－１临氢降凝催化剂进行临氢降凝，可以生产出絮凝点小于－４７℃的全封闭冷冻机油。     

He-Ne激光633nm腔内倍频紫外激光器

利用碘酸锂晶体对Ｈｅ－Ｎｅ激光器６３２．８ｎｍ谱线进行腔内倍频，得到了３１６．４ｎｍ的连续紫外输出。对光学元件进行优化后，采用的三镜折叠谐振腔给出了１．５ｍＷ的紫外光输出