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A direct method for evaluating equilibrium vapor compositions from measurements of the vapor pres-sure or boiling point of the solutions is presented.The basic differential equations are derived from Gibbs-Duhem equation and can be solved easily by iterative method.This method can be successfully used forbinary systems,and in principle can also be applied to multicomponent systems.Several examples ofbinaries and ternaries are presented for demonstration.Calculated results are in good agreement with ex-perimental data. 相似文献
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using close-packed lattice models,a continuous thermodynamic framework is presented forphase-equilibrium calculations for binary solutions with a polydisperse polymer solute.An expressionfor the Helmholtz function of mixing is based on the revised Freed model developed previously.Asize parameter c_r and an energy parameter ε are used;the former can be temperature dependent,while the latter can depend on both temperature and chain-length of the polymer.The discretemulticomponent approach is adopted to derive expressions for chemical potentials,spinodals and criti-cal points.The continuous distribution function is then used in calculations of moments occurring inthose expressions.Computation programs are established for cloud-point-curve,shadow-curve,spinodal and critical-point calculations for polymer solutions with standard distribution or arbitrarydistribution of polymer.In the latter case,the derivative method developed previously is applied.lllustrations for phase-equilibrium calculations are shown 相似文献
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聚合物的内压与新溶解度参数 总被引:3,自引:0,他引:3
由文献发表的pVT数据回归得到了许多液态聚合物的Tait方程参数。据此能够获得各种密度下聚合物的等容线。将这些等容线斜率的对数与密度作图,则无例外地发现这些作出的线是很好的直线,故可建立一个聚合物的通用内压方程。它有两个特性常数,分别决定于直线的斜率和截距。它能用来准确地计算298.15K时各种液态聚合物的内压;据此,得到了90个聚合物的新溶解度参数值。 相似文献
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