Abstract

Two groups of experimental data obtained in the vicinity of the critical point are discussed. Group I describes the level h_t of the meniscus separating the two phases of the substance in the cell. The measurements were performed for SF₆ under the condition (g = 9.8 m s^–2) during an experiment conducted in a space laboratory. Group II includes data on the density of liquid and vapor measured for C₆F₆ along the saturation curve under terrestrial condition. In both cases, the studied two-phase sample is located in a horizontal cylindrical cell. In the second experiment, the gravitational effect was also measured along the isotherms as the dependence of the sample density on the height h measured from the bottom of the cell. An equation relating the h_t level (experiment I) with such functions as the order parameter f_s and the average diameter f_d is derived in this work. The obtained equation describes the initial experimental data at relative temperatures τ = (T – T_c)/T_c = 2 × 10^–6–0.01. An approach is considered that takes into account the influence under microgravity (g = g_M ⪡ 9.8 m s^–2) on the height h (experiment II). The dependences that represent f_s and f_d and the density of the liquid and gas phases along the saturation curve of these substances are obtained. These dependences agree satisfactorily with the results of experiments I and II in a wide temperature range and correspond to the scaling theory of critical phenomena.

中文翻译：

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微重力作用下C 6 F 6和SF 6相边界的研究

摘要

讨论了在临界点附近获得的两组实验数据。第一组描述了分离细胞中物质两相的弯液面的高度h _t。在太空实验室进行的实验中，是在条件（g = 9.8 ms ^–2）下对SF ₆进行测量的。第二组包括有关C ₆ F ₆的液体和蒸气密度的数据沿地面条件下的饱和度曲线。在这两种情况下，研究的两相样本都位于水平圆柱单元中。在第二个实验中，还沿着等温线测量了重力效应，即样品密度与从电池底部测量的高度h的关系。在这项工作中，推导了将h _t水平（实验I）与阶数参数f _s和平均直径f _d等函数相关的方程。得到的方程式描述了相对温度τ=（T – T _c）/ T _c = 2×10时的初始实验数据。^–6 –0.01。一种方法被认为是，考虑到微重力条件下的影响（克=克_中号⪡9.8毫秒^-2上的高度）H ^（实验Ⅱ）。获得了代表f _s和f _d的依赖性以及沿着这些物质的饱和曲线的液相和气相密度的依赖性。这些依赖性与在宽温度范围内的实验I和II的结果令人满意地吻合，并且与临界现象的定标理论相对应。