氦制冷机和液化器中的纯化系统

主要介绍了氦制冷机和氦液化器中应用的几种典型的氦纯化器的工作原理，主要工作程序和优缺点，并介绍了讨论了几种氦纯化器的设计方案，吸附量和计算以及可用于氦纯化器的工程设计。     

新型氦气体轴承透平膨胀机的研制

着重介绍所开发的新型氦气体轴承透平膨胀机的主要设计参数及关键部件的结构，该氦气体轴承透平膨胀机用于空间环境模拟的氦制冷系统，在设计中，利用多目标优化程序获得了较好的热力性能及较高的失稳转速，同时还开展了不同工质的相似模化研究，以便更好地预测氦透平膨胀机的热力性能，为了测试透平膨胀机的热力性能及机械性能，进行了多次的常温空气试车及液氮级温度低温试车，试验结果及现场实际车结果表明氦气体轴承透平膨胀机具有优异的热力性能及机械性能，满足了神舟号飞船发射前的热真空试验要求。     

Direct Measurements of Quantum Turbulence Induced by Second Sound Shock Pulses in Helium II

Direct measurements in a wide channel of He II at 1.7 K are presented of quantum turbulence induced by second sound shock (SSS) pulses. Such pulses are moving volume sources of power flux density, with the Vinen and Hall equation not directly applicable. Instead, a fit based on an electric field energy analogy is introduced, a leaky capacitor fit (LCF), for the purpose of extracting a growth and decay characterization of the apparent induced quantum turbulence from the measurements, with the fit parameters tabulated. Also, an explicit energy account is taken of the quantum turbulence as well as of the inducing SSS pulses. Plotting pulse energy transport fraction versus initial energy flux density, a breakpoint energy flux density is proposed for the onset of Gorter–Mellink thermal diffusion in the presence and absence of a quantum turbulence background. This is in contrast with a breakpoint power flux density discussed by previous researchers. This breakpoint energy flux density is about 75 J/m ² in the absence of a background, in quiescent He II at 1.7 K, and is thus a characteristic of all SSS pulses.     

氦离子化检测器气相色谱法分析氦中微量氖

论述了用氦离子化检测器气相色谱法分析氦中微量氖的方法及结果。     

模板法制备聚乙烯咔唑纳米结构中的浸润转变

采用溶液浸润多孔阳极氧化铝模板(AAO)的方法,在孔径为200nm的AAO模板中制备功能聚合物聚乙烯咔唑(poly(vinyl carbazole),PVK)一维纳米结构.SEM和TEM测试结果表明,2.5%和3.5%(质量分数)的PVK溶液可制得纳米管,其外径约为200nm,管壁厚度分别为30与70nm;而5.0%与10.0%(质量分数)的PVK溶液可制得纳米线,其直径约为200nm.提出了溶液浸润模板法中的完全浸润体系和部分浸润体系以及临界浸润浓度Cw.     

Viscosity of Toluene+Cyclopentane Mixtures: Measurements and Prediction

New measurements of the viscosity of binary mixtures of toluene+cyclopentane are presented. The measurements, performed in a vibrating-wire viscometer, cover the temperature range from 210 to 310 K at pressures up to 25 MPa. The concentrations studied are 60 and 30%, by weight, toluene. The uncertainty of the measurements, confirmed at room temperature and higher temperatures with the measurement of the viscosity of water, is estimated to be ±0.5%, increasing to ±1% at temperatures below 240 K. The present measurements are employed to examine the predictive power of two recent theoretically based schemes proposed for the calculation of the viscosity of mixtures.     

Equation of State of He-H2 and He-D2 Dense Fluid Mixtures at High Pressures and Temperatures

The fluid variational theory is used to calculate the Hugoniot equation of state (EOS) of He, D₂, He + H₂, and He + D₂ fluid mixtures with different He:H₂ and He:D₂ compositions at high pressures and temperatures. He, H₂, and D₂ are the lightest elements. Therefore, the quantum effect is included via a first-order quantum correction in the framework of the Wigner-Kirkwood expansion. An examination of the reliability of the above computations is performed by comparing experiments and calculations, in which the calculation procedure used for He and D₂ is adopted also for He + D₂ and He + H₂, since no experimental data for the mixtures are available to conduct these comparisons. Good agreement in both comparisons is found. This result may be seen as an indirect verification of the calculation procedures used here, at least, in the pressure and temperature domains covered by the experimental data for He and D₂ used for comparisons, which is nearly up to 40 GPa and 10⁵ K. Also, the equation of state of He + H₂ fluid mixtures with different compositions is predicted over a wide range of temperatures and pressures.     

高纯氦气体标准物质的研制

论述了高纯氦标准物质的研制结果、实验方法以及误差分析等。     

空调两器检漏设备氦气回收纯化装置的试验研究

本文试验研究了一种针对空调两器检漏设备的氦气回收纯化装置,研究结果表明,该装置可以有效地将空调两器检漏设备内氦气纯度维持在80%以上,该工艺的氦气使用量约为6.7m³/天,远小于未使用该工艺时系统因纯度低而排放的氦气量(约128m³/天),考虑到企业实际使用该装置的经济性要求,提出了该装置后续工艺优化的方向。     

低温容器的氦质谱检漏

分析了大、小型低温容器的氦质谱检漏的各自特点及应注意的问题，讨论了部分国产氦质谱检漏仪的应用特点。     

Supersolidity and the Thermodynamics of Solid Helium

The specific heat of solid helium in the temperature range below about 1.2 K has been found to contain a term varying as T ⁷, in addition to the usual T ³ contribution always found in a crystalline dielectric solid. It has been proposed by Anderson, Brinkman and Huse, (Science 310, 1164 (2005)) that the existence of this T ⁷ term supports their theory of supersolidity. However, in this paper we show that corrections to the phonon specific heat arising from phonon dispersion are much larger than expected based on simple order of magnitude estimates and, as a consequence, it is very unlikely that the existence of this T ⁷ term can be considered as evidence for supersolidity.      

不锈钢高温氦脆(HTHE)问题

扼要地介绍了不锈钢高温氦脆的研究概况，主要包括高温下氦在不锈钢中的分布和生长机制，以及高温下氦的分布对其力学性能的影响。     

Viscosity and Density Measurements of Binary Mixtures Composed of Methylcyclohexane + cis-Decalin Versus Temperature and Pressure

Viscosity and density measurements have been carried out for binary mixtures composed of methylcyclohexane + cis-decalin in the temperature range 293.15 to 353.15 K and at pressures up to 100 MPa. The viscosity was measured with a falling-body viscometer, except at atmospheric pressure where an Ubbelohde viscometer was used. The experimental uncertainty for the measured viscosities is 2%. The density was measured up to 60 MPa and extrapolated by a Tait-type relationship to 100 MPa. For the reported densities the uncertainty is less than 1 kgm^–3. An evaluation of the simple mixing laws of Grunberg and Nissan and of Katti and Chaudhri, which require only the density and viscosity of the pure compounds, showed that they can represent the viscosity of the binary mixtures with an average absolute deviation of 2%, corresponding to the experimental uncertainty.     

Dynamics of Liquid Helium Wetting on Real Surfaces

Interest about wetting properties of liquid helium on weakly binding substrates was recently focused on dynamical properties. The motion of liquid film border near prewetting transitions has been investigated, as well as meniscus edge dynamical properties. Depending on substrate quality, an hysteretic dynamics is observed due to line pinning. It may interfere with the observation of the transition, in addition to the intrinsic thermal hysteresis associated with its first order nature. Experimental results and models put forward to explain them will be discussed.     

大型氦低温系统中的杂质净化

EAST是一个全超导的托卡马克核聚变实验装置,磁体采用超临界氦迫流冷却.磁体在降温过程中对氦气的纯度有很高的要求,净化系统是整个低温系统的重要环节之一,以防各种杂质气体在低温下凝结固化威胁低温系统的稳定可靠运行.理论分析了氦气纯化的基本原理及固定床吸附器的吸附机理,对低温纯化器的运行进行了阐述,并介绍了杂质成分检测系统,以对净化效果进行评估,实验得知氦气净化系统能满足低温系统氦气高纯度的要求.     

模板浸润法制备可生物降解聚合物纳米管和纳米线

以孔径为200nm的阳极氧化铝（AAO）为模板，用简单的物理方法制备了生物可降解聚合物聚己内酯（PCL）的纳米管、线及其阵列结构。SEM和TEM测试结果表明：熔融法在120℃和140℃都能制得整齐的纳米管阵列结构，管径均匀，约300nm。在溶液法中，5％浓度的溶液制得了杂乱的纳米管，而10％浓度的溶液制得的是纳米线阵列，直径在200nm左右。     

Wetting of Rough Walls

Quenched geometric disorder of a wall delimiting a spectator phase can have dramatic effects on the nature of critical wetting transitions. We consider self-affine walls in 2D with roughness exponent _W. Transfer matrix results for directed interfacial models with short-range interactions suggest that wetting turns first-order as soon as _W exceeds ₀, the anisotropy index of interface fluctuations in the bulk. Discontinuous interface depinning is best identified by a peculiar two-peak structure in the statistical distributions of wall–interface contacts obtained by sampling over disorder. On the other hand, for _W<₀ wetting remains continuous, most plausibly in the same universality class as with flat walls. This occurs both with ordered (₀ = 1/2) and with bond-disordered (₀ = 2/3) bulk. A precise location of the thresholds at _W = ₀ can be argued on the basis of an analysis of different terms in the interfacial free energy. This analysis elucidates the peculiar role played by the intrinsic interfacial roughness and suggests extensions of the results to 3D and to long-range substrate forces.     

Properties of Electron Bubbles in Liquid Helium

We present calculations of a number of properties of electron bubbles in liquid helium. The size and shape of bubbles containing electrons in different quantum states is determined based on a simplified model. We then find how the geometry of these bubbles changes with the applied pressure. The radiative lifetime of bubbles with electrons in excited states is calculated. Finally, we use a quantum Monte Carlo method to determine the properties of a bubble containing two electrons. We show that this object is unstable against fission.