碳酸二甲酯-乙醇体系等压汽液相平衡

采用双循环汽液平衡釜测定了碳酸二甲酯-乙醇在100 kPa下的汽液平衡数据。实验数据经Herington面积积分法校验符合热力学一致性。运用M atlab中的非线性最小二乘法程序,对二元汽液平衡的W ilson模型进行参数计算,利用关联出的模型参数计算相应的汽相组成,并与实验值比较,其平均绝对偏差为0.002 8,表明二者符合良好,这为建立碳酸二甲酯和乙醇的精馏分离数学模型提供了基础数据。     

Co-Cu-Zn三元系相平衡的实验研究

本实验通过采用电子探针显微分析和X-ray衍射分析方法实验研究了Co-Cu-Zn三元体系在800°C和1000°C时的相平衡。在这两个等温截面中均未发现三元化合物。在800°C等温截面,Co在β-CuZn相中的固溶度为32.36%,Cu在β1-CoZn相中的固溶度为5.28%。除此之外,γ-Co5Zn21和γ-Cu5Zn8具有相同的晶体结构,因此,它们之间形成了一个贯穿连续固溶体相。1000°C的等温截面中,β-CuZn相、β1-CoZn相、γ-Co5Zn21相、γ-Cu5Zn8相都消失了。随着温度从800°C上升到1000°C,液相区域增大。     

遗传算法在C7+临界性质估算中的应用

研究烃类体系的相态特征对凝析气田的开发和开采有着重要的意义.应用组分模型对凝析气藏进行模拟时,大量的时间耗费在相态的计算上.在烃类体系中C7+以上的重组分对流体性质的影响最大,因此必须对组成烃类体系重组分的临界性质进行估算.应用遗传算法确定C7+组分的临界性质,并利用PR状态方程进行相平衡计算.对应用遗传算法预测的结果、室内定容衰竭实验结果和应用Eclipse软件计算的结果进行了对比,结果表明,文中提出的方法所得到的结果和室内实验结果符合程度更高.     

离子液体在萃取精馏领域应用的基础性研究进展

综述了近年来离子液体在萃取精馏领域应用的基础性研究进展。主要介绍了在离子液体中的无限稀释活度系数的测定、汽液平衡的测定、含离子液体物系相平衡与活度系数模型研究以及离子液体萃取精馏的应用。目前离子液体用于萃取精馏存在基础性研究不足、生产成本高和工程应用等方面的问题。     

Cu-Ni-Sn: A Key System for Lead-Free Soldering

Being the most complex constituent of the quaternary system Ag-Cu-Ni-Sn, the ternary system Cu-Ni-Sn is the key system for the investigation of the interactions of Ag-Cu-Sn solder alloys with Ni as a contact material. Although this system has been thoroughly studied in the literature, there are still many uncertainties left. In the present work, a study of the phase equilibria in four isothermal sections at 220, 400, 500, and 700°C of the Cu-Ni-Sn system was carried out following a comprehensive literature study. The methods employed were x-ray diffraction (XRD), metallography, and scanning electron microscopy including electron probe microanalysis. The ternary solubilities of the Ni₃Sn₂-Cu₆Sn₅ and Ni₃Sn-Cu₃Sn fields were characterized in detail. So far no continuous solubility between the respective phases has been found. At 25 at.% Sn the existence of two ternary compounds formed from the BiF₃-type (Cu,Ni)₃Sn phase and reported in literature could be confirmed. On the other hand, our results differ significantly from the very recent literature related to lead-free soldering.     

固液平衡关系的推算研究

本文为解决二组元连续固体溶液型固液平衡的熔化线测定的困难,提出了一种推算方法。即在实验准确测得凝固线的情况下,经热力学推导,得出各组分的无限稀释活度系数,然后由Van Laar方程关联液相活度系数,从而推算出熔点线。最后,对已知固液平衡关系的实际体系应用此法进行了推算验证。     

Reaction of Cerium Oxide with Zirconium and Yttrium Oxides at 1250°C

Phase relationships in the ternary system ZrO₂ Y₂O₃ CeO₂ were investigated by x-ray diffraction analysis and electron microscopy for the first time, and phase relationships in the binary systems ZrO₂ CeO₂ and CeO₂ Y₂O₃ defined more accurately at 1250°C over the entire range of concentrations. The 1250°C isothermal section of the phase diagram for ternary system was constructed. Specimens were prepared from nitrate solutions by evaporation, drying, grinding, and subsequent annealing at 1250°C. The systems were characterized by the formation of broad solid solution ranges based on C -Y₂O₃, F-CeO₂, F-ZrO₂, and narrow based on T-ZrO₂ and -phase. No new phases were found in the systems. The path of isoparametric lines in the F-ZrO₂ solid solution field suggests that yttrium and cerium ions can substitute for each other without appreciable substitution of zirconium ions.     

Precise Measurements of the Vapor-Liquid Equilibria (VLE) of HFC-32/134a Mixtures Using a New Apparatus

A new apparatus for precise measurements of the vapor-liquid equilibria of mixtures by the circulation method has been developed. This apparatus has two special components: a high-stability temperature control system and a helium pressurization system. The temperature in the liquid bath surrounding the sample cell is kept constant within ±0.5mK. The helium pressurization system increases the pressure of the sampled mixture when measuring the compositions at low temperatures by gas chromatography. With these components, the uncertainty in measuring the vapor-liquid equilibria has been reduced. Using this apparatus, the vapor-liquid equilibria of HFC-32/134a mixtures were measured in a temperature range of 263.15 to 293.15K. These results are in good agreement with the calculated results from REFPROP (Ver. 6.01) with a relative pressure difference of about 2%.     

高压汽液平衡的统计回归与推算(Ⅱ)

对前文（Ⅰ）[10]中的二元统计回归结果中的两组回归结果进行了残差分析，进一进证实了新的DDLC-SRK模型优于SRK方程,同时还对DDLC-SRK模型证实了统计回归方法求得的参数更为可靠．另外进行了三元高压汽液平衡的推算，结果表明，应用DDLC-SRK模型的统计回归推算精度优于其经典方法，而应用SRK方程的统计回归推算精度与其经典方法相近。