太阳能热利用的现状和发展

开发利用新能源，尤其是太阳能，对人类环境的改善和社会的发展具有重要的战略意义。综述了国内外在太阳能热利用方面的现状及发展前景     

气体动压轴承动态参数测定原理

将气体动压轴压简化为转化气膜系统后，针对其动力特点，给出气膜在微幅振动下动压轴承的实用数学模型和测定动态参数的方法，并进行了测量误差的修正。     

网络新闻及其使用

本文介绍了Ｉｎｔｅｒｎｅｔ中网络新闻及其订阅，检查，阅读，消息文件的删除，发送新闻，新闻组的建议以及使用中应注意的事项。     

谈信息资源管理软件的开发及利用

文章重点阐述了在高职院校信息资源管理艰难的大环境下,我院信息资源管理软件开发使用的环境及过程,重点论述了管理软件的具有的特色及使用过程中遇到的问题。     

Equations of state for hard-sphere fluids

Equations of state and contact values of hard-sphere radial distribution functions (rdf's) which are given by a linear combination of the Percus— Yevick and scaled-particle virial expressions are considered. In the one-component case the mixing coefficient() is, in general, a function of the volume fraction. In mixtures the coefficient( _i ,d _i ), in general, depends upon the volume fraction _i , and diameterd _i , of each species,i andj. For the contact valuesY _ij of the rdf's, the mixing coefficients _ij ( _k ) also depend on speciesi andj. Density expansions for the exact for the one-component hard-sphere fluid are obtained and compared with several approximations made in earlier works and in our own work, as well as with simulations. For a mixture, it turns out that one cannot obtain the exact fourth virial coefficient by using a linear combination of the Percus-Yevick and scaled-particle virial expressions forY _ij unless one allows _ij to depend on mole fractionsx _i even at the zeroth order of its density expansion. We also find that _ij must depend on particle speciesi andj in order to satisfy the exact limits obtained earlier by Sung and Stell. A new equation of state for the binary hard-sphere mixture which satisfies all the exact limits we have considered is suggested.Paper presented at the Tenth Symposium on Thermophysical Properties, June 20–23, 1988, Gaithersburg, Maryland, U.S.A.     

A comparative study of transient waves in random (polycrystalline) media

The paper investigates the transient response of a random medium as predicted by two methods, a perturbation scheme and a causal approach. It is shown by direct computation of a pulse propagation that the perturbation scheme yields an advanced response inconsistent with the physical realizability of the medium. The causal model as well as a modified perturbation scheme exhibit a physically reasonable behavior.     

Effective vehicle width in self-paced tracking

In self-paced tracking tasks, such as driving, the speed is related to the lateral tolerance. This lateral tolerance has been varied in two ways in previous studies by changing the track width for constant vehicle width and vice versa. The current study used both an automobile driving task and a computer/mouse task to show that these two ways of varying lateral tolerance did not produce equivalent results. Subjects behaved as if vehicle width were less important than track width. Speeds and errors both increased as vehicle width increased for a constant lateral tolerance. This could have safety consequences when driving in confined spaces.     

含钼废渣冶炼钼铁的优化试验

利用含钼废料钼酸钙为原料,采用碳还原法冶炼钼铁,通过单因素分析试验及正交试验优化得出最佳的试验条件,钼酸钙加入量应低于10%,熔炼温度为1 525 ℃,保温时间为25 min,碱度为1.3。通过XRD、SEM、EDS分析得出用此方法生产得到的钼铁合金中,钼以Mo₂C、Fe₃Mo以及Fe₃Mo₃C的形式存在,渣系为二元玻璃渣系,具有与普通玻璃相似的成分系统。经测定合金中钼的回收率大于99%,钼资源回收效益可观。     

预分离色谱法直接测定微量组份无限稀释活度系数

预分离色谱法可直接测定混合物中微量组份的无限稀释活度系数(γ~∞),而不必把此组份从混合物中分离出来。主要由四步组成:被测组份的预浓缩,被测组份的定性,选择预分离柱和γ~∞的测定。预浓缩样品经过预分离柱分出被测组份,然后进入测量柱测定γ~∞。此方法简捷、可靠与常规以纯溶质进样的色谱测y~∞的方法具有相同的测定精度,可广泛用于缺少纯样的场合。用此法测定了戊烯-1-炔-4、丁炔-2在若干酸醇中的γ~∞,分别求得了修正和未修正的UNlFAC参数,对kikic修正模型其值为ac=c,CooH=694.9(K)acooH,c=c=-99.08(K),ac=c,oH=812.99(K),aoH,c=c=143.36(K)     

Determination of the solubility parameter of poly(ethylene oxide) at 25°C by gas-liquid chromatography

The solubility parameter of poly(ethylene oxide) at 25°C has been determined using the method developed by DiPaola-Baranyi and Guillet, by the extrapolation of the values of the interaction parameter χ, at high temperatures, ranging from 70°–90°, 90°–110° and 110°–130°C down to 25°C. The values of the solubility parameter obtained, depending on the temperature ranges employed, are 9.8, 9.9 and 10.1, respectively.