低温下液体饱和蒸气压的测试

着重介绍了静态法测试低温下（－１００～５０℃）液体饱和蒸气压的原理及方法，给出了低温下液体全氟三乙胺饱和蒸气压的测试结果，并进行了讨论。     

低温容器泄压装置的容量要求

无论流体热力学状态如何，根据热导率和比热输入所导出的方程，可计算其泄压装置的容量要求。该方程适用于液体全液排出、饱和液体和汽-汽排出、饱和液体和汽-液排出，以及超临界液体系统的普遍情况。     

全氟甲烷(CF4)饱和蒸气压在139.53 K～217.53 K温度范围内的实验

在温度范围139．53K-217．53K内,采用自行设计的循环法实验装置精确测量了30组CF4（R14）的饱和蒸气压实验数据,并且运用Wagner方程和另一种Wagner型方程对实验数据进行了拟合。对计算值与实验数据进行了偏差分析,结果显示两种方程的计算值非常接近,与实验数据拟合地较好,从而得到以上温度范围内的CF4饱和蒸气压方程。     

异丁烷(R600a)饱和蒸气压的实验研究

利用改进的Burnett法PvTx实验台,精确测量了66组R600a饱和蒸气压实验数据.温度测量范围为253-393 K,压力测量范围为73-2833 kPa;温度测量偏差不大于±10 mK,压力测量偏差不大于±870 Pa.提出了一个新的R600a饱和蒸气压方程,方程适用温度范围为120 K到临界温度,与已有实验数据进行了比较,还计算得到了R600a的正常沸点和偏心因子值.     

基于半色调实地的纽介堡方程修正方法

目的从网点墨量与实地墨量不同的角度出发,构建基于半色调实地三刺激值的纽介堡方程修正模型,从而提高纽介堡方程的计算精度。方法以符合G7认证的印刷标准文件为研究对象,从网点墨量与实地墨量不同的角度出发,通过求解半色调实地三刺激值,构建基于半色调实地三刺激值的纽介堡方程修正模型,利用色差法对该修正模型进行精度验证。结果验证结果表明,修正模型色差精度最大可以提高2.2 NBS,平均色差精度可以提高1.0 NBS。结论基于半色调实地三刺激值的纽介堡方程修正模型能够有效提高方程精度,研究结果对于印刷分色具有重要意义。     

二氧化碳在液氧和液氮中的溶解度

求取固体二氧化碳在液氮和液氧等低温液体中的溶解度，对于控制低温流体中二氧化碳的含量至关重要。在理想溶液的基础上，采用了适用于非极性溶质-溶剂的系统的正规溶液关系式和修正的Scatchard-Hildebrand关系式，对二氧化碳在液氮和液氧中的溶解度进行了计算，并与文献中的实验数据进行比较，给出了较为合理的结果，可供工程应用参考。     

混合工质R134a/R23焓-浓度图的绘制

使用PR(Peng-Robinson)方程对混合工质R134a/R23进行了气液相平衡的预测和焓、熵的计算.针对PR方程液相精度比较差的问题,对PR方程引入了修正系数,重新推导了逸度系数、余函数等表达式,并将计算结果与实验数据进行了比较.根据计算得到的R134a/R23热物性数据,绘制了工程上广泛使用的二元混合工质的焓-浓度图,为基于该混合工质的循环计算,提供了重要的基础数据.     

纽介堡方程计算精度的研究

研究了纽介堡方程的计算精度,即用不同尤尔-尼尔森系数n修正的纽介堡方程计算印品青、品、黄的网点百分比,然后讨论计算精度.实验发现,随着n值的增大,纽介堡方程计算精度降低,且黄色对n值最敏感.     

HFC-125的饱和蒸气压实验研究

本文实测了从291K．337K范围内24对HFC-125饱和蒸气压的数据,并由实验数据拟合得到了HFC-125的蒸气压方程。实验数据的最大不确定度小于1．2kPa。蒸气压方程与实验值的偏差在0．022％以内。应用该方程外推得到了HFC-125的临界压力,导出了HFC-125的汽化潜热方程。     

饱和土层中Love波的传播特性

基于Ｂｉｏｔ的液体饱和孔隙介质模型，考虑孔隙流体粘性，导出了弹性半空间上饱和土层中Ｌｏｖｅ波的复频散方程，然后将其转化为两个实方程并利用迭代的方法进行求解。讨论了Ｌｏｖｅ波的波速范围、Ｌｏｖｅ波的频散和衰减特性以及Ｌｏｖｅ波的位移分布。     

Density of Ni-Al Alloys in Liquid and Solid-Liquid Coexistence State Measured by a Modified Pycnometric Method

The density of Ni-AI alloys in both liquid state and solid-liquid coexistence state was measured with a modified pycnometric method. It was found that the density of Ni-AI alloys decreases with increasing temperature and Al concentration in the alloys. The molar volume of liquid Ni-AI binary alloys increases with the increase of temperature and Al concentration. The partial molar volume of Al in Ni-AI binary alloy was calculated approximately. The molar volume of liquid Ni-AI alloy determined in the present work shows a negative deviation from the ideal linear molar volume.     

Density of Liquid Ni-Mo Alloys Measured by a Modified Sessile Drop Method

The density of liquid binary Ni-Mo alloys with molybdenum concentration from 0 to 20% (mass fraction) wasmeasured by a modified sessile drop method. It has been found that the density of the liquid Ni-Mo alloys decreaseswith increasing temperature, but increases with the increase of molybdenum concentration in the alloys. The molarvolume of liquid Ni-Mo binary alloys increases with the increase of temperature and molybdenum concentration. Thepartial molar volume of molybdenum in Ni-Mo binary alloy has been approximately calculated as [13.18-2.65×10~(-3)T+(-47.94+3.10×10~(-2)T)×10~(-2)X_(Mo)]×10~(-6)m~3·mol~(-1). The molar volume of Ni-Mo alloy determined inthe present work shows a negative deviation from the ideal linear mixing molar volume.     

Saturated Humidity, Entropy, and Enthalpy for the Nitrogen-Water System at Elevated Temperatures and Pressures

A model is used to calculate saturated thermophysical properties (humidity, entropy, and enthalpy) of a nitrogen-water mixture at elevated temperatures and pressures. In the model, a modified Redlich–Kwong equation of state is used to calculate fugacity coefficients for the vapor phase, and the liquid phase follows Henry's law. The model has been investigated by comparing the calculated results with the available experimental data. The comparison shows that the model can be used to calculate saturated thermodynamic properties for the nitrogen-water mixture reliably up to 523.15 K and 300 bar.     

Bubble pressures and saturated liquid molar volumes of difluoromonochloromethane—fluorochloroethane binary mixtures: experimental data and modelling

A previously described apparatus (variable volume cell method) was used to obtain bubble pressures and saturated liquid molar volumes at four temperatures for systems involving difluoromonochloromethane with tetrafluorodichloroethane, trifluorotrichloroethane and difluoromonochloroethane. The experimental bubble pressures are well represented by the Peng-Robinson equation of state with one adjusted interaction parameter. Adjusting a second interaction parameter does not significantly improve the representation. Soave and Mathias equations give a quite similar representation. Saturated liquid molar volumes calculated from the different equations of state, with binary interaction parameters adjusted on bubble pressure data, do not agree well with experimental results: the standard deviation between calculated and experimental densities is ≈ 8% with the Peng-Robinson equation of state and ≈ 18% with that of Soave and Mathias.     

Calculation of the density of liquid radon

Eleven condensed gases were investigated to relate their critical molar volume V_c to their molar volume V_o:V_o is the molar volume where the fluidity Φ = 0. From this relationship the critical density of radon was calculated ?_c = 1613 kg m.^?3 From the principle of corresponding states for viscosity and with this value for ?_c the density for the saturated liquid state of radon was predicted.     

The viscosity of the refrigerant 1,1-difluoroethane along the saturation line

The viscosity coefficient of the refrigerant R152a (1,1-difluoroethane) has been measured along the saturation line both in the saturated liquid and in the saturated vapor. The data have been obtained every 10 K from 243 up to 393 K by means of a vibrating-wire viscometer using the free damped oscillation method. The density along the saturation line was calculated from the equation of state given by Tamatsu et al. with application of the saturated vapor-pressure correlation given by Higashi et al. An interesting result is that in the neighborhood of the critical point, the kinematic viscosity of the saturated liquid seems to coincide with that of the saturated vapor. The results for the saturated liquid are in satisfying agreement with those of Kumagai and Takahashi and of Phillips and Murphy. A comparison of the saturatedvaport data with the unsaturated-vapor data of Takahashi et al. shows some discrepancies.Paper dedicated to Professor Joseph Kestin.     

Density of Liquid Ni-Cr Alloy

The density of liquid Ni-Cr alloy was measured by a modified sessile drop methold.The density of liquid Ni-Cr alloy was found to decrease with increasing temperature and Cr concentration in the alloy,The molar volume of liquid Ni-Cr alloy increases with increasing the Cr concentration in the alloy ,The molar volume of Ni-Cr alloy determined in the present work shows a positive deviation from the linear molar volume.     

Thermodynamic Properties of Liquid 3He-4He Mixtures Between 0–10 bar below 1.5 K

The thermodynamic properties of liquid ³He-⁴He mixtures at pressures of up to 10 bar and temperatures below 1.5 K are determined. The calculations are based on previously determined thermodynamic properties of ³He-⁴He mixtures at saturated (zero) pressure, and available experimental measurements of the molar volume, which are used to determine an expression for the molar volume. Since available experimental data for mixtures at higher pressures are restricted to low temperatures (below about 0.7 K), the calculated molar volumes at high pressure and high temperature are largely based on pure ³He and pure ⁴He data.     

Measurements of the refractive index of alternative refrigerants

Measurements of coexistence curves of the refractive index of HCFC-22, HFC23, HFC-32, HFC-125, and HFC-152a have been carried out in the range from ambient to critical temperature. Near the critical temperature the refractive index has distribution in both the vapor and the liquid phases in the test cell. Thus the values at the boundary between vapor and liquid are selected at those of saturated vapor and liquid, respectively. The values of the critical temperature and critical refractive index for each substance are estimated. The refractive index is related to density by the Lorentz-Lorenz equation. In the case of HFC-32 the value of the LL function is assumed to be constant in the limited region near the critical point, and the values of density of saturated vapor and liquid are calculated and are compared with the experimental values of density obtained byPVT measurement.Paper presented at the Twelfth Symposium on Thermophysical Properties, June 19–24, 1994, Boulder, Colorado, U.S.A.     

Physical properties of Freon 216

The following properties of Freon 216 are determined over a wide temperature range: density of the liquid and its saturated vapor; surface tension on the boundary with the saturated vapor; liquid dynamic viscosity; saturated vapor pressure. In addition, the critical temperature and fusion temperature are determined.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 59, No. 1, pp. 122–126, July, 1990.