醇-水-氯化锂体系汽液平衡

用改进的Othmer汽液平衡釜测定了 0 .1MPa下乙醇 /异丙醇 /正丙醇 -水 -氯化锂体系在不同恒盐摩尔分率下的汽液平衡数据 ,并用Mock模型、Sander模型、Macedo模型和Kikic模型对实验数据进行了关联 ,结果良好     

含缔合组分多元体系汽液平衡的研究及数理统计方法的应用(一)——甲酸-乙酸-水-乙酸甲酯四元体系汽液平衡的研究

本文解决了甲酸-乙酸-水-乙酸甲酯四元体系的分析方法,采用改进的Rose釜测定了这组体系在760mmHg下的互溶部分的汽液平衡数据。在二元缔合模型的基础上建立了一个含两个缔合组分的四元体系的热力学模型,分别用UNIQUAC方程[配位数Z=10及Z=Z(T)]、多参数Wilson方程、NRTL方程和Wilson方程从对应的六个二元体系汽液平衡数据关联所得的模型参数推算了四元体系的汽液平衡数据及对应的三元体系的汽液平衡数据,实验数据与推算结果的符合程度是令人满意的,尤其是Z=Z(T)的UNIQUAC方程的推算结果最好。     

101.3kPa下异丙醇-异丁醇-正丁醇汽液平衡的测定与关联

用改进的Rose釜测定了101.3 kPa下异丙醇-异丁醇、异丙醇-正丁醇、异丁醇-正丁醇3个二元体系及异丙醇-异丁醇-正丁醇1个三元体系的汽液平衡数据。3组两元汽液平衡数据均通过了Herington热力学一致性检验,三元汽液平衡数据也通过了McDermett-Ellis热力学一致性检验。分别用Wilson、NRTL和UNIQUAC方程对二元汽液平衡数据进行了关联,得到了相应的模型参数及关联偏差。对于3个二元体系而言,Wilson和UNIQUAC模型方程比NRTL模型方程的关联效果好。最后运用关联得到的Wilson二元交互作用参数预测了三元体系的汽液平衡数据,平衡温度的平均绝对偏差为0.52℃,异丙醇的汽相摩尔组成平均绝对偏差为0.0057,异丁醇的汽相摩尔组成平均绝对偏差为0.0048,实验值与预测值基本吻合。     

乙醇-水-盐体系汽液平衡

用改进的Ｏｔｈｍｅｒ汽液平衡釜在０．１０１３ＭＰａ下测定了乙醇水氯化钙、醋酸钾体系在恒盐摩尔分率下的汽液平衡数据。用Ｆｕｒｔｅｒ方程、修正的Ｆｕｒｔｅｒ方程、拟二元模型及溶剂化模型对实验数据进行关联，取得良好结果，其中乙醇水氯化钙体系实验数据用修正的Ｆｕｒｔｅｒ方程关联，所得汽相平均偏差为０．０１２４。     

异戊醇-乙二醇体系等压汽液相平衡研究

利用双循环汽液平衡釜测定 10 1.3kPa下异戊醇 乙二醇体系的汽液平衡数据x y t,并运用该实验结果 ,进一步获得组分的液相活度系数。实验数据经Herrington方法检验 ,表明符合热力学一致性。用Wil son模型对该实验数据进行处理 ,计算结果与实验值的平均绝对偏差为 0 .0 0 6 3,取得满意的效果。     

水-醋酸-N-甲基吡咯烷酮体系等压汽液平衡研究

用改进的Rose釜测定了醋酸-N-甲基吡咯烷酮、水-醋酸-N-甲基吡咯烷酮在101.33 kPa下的等压汽液平衡数据。醋酸-N-甲基吡咯烷酮体系的汽液平衡数据通过了热力学一致性检验。用NRTL、W ilson和UNIQUAC模型对醋酸-N-甲基吡咯烷酮体系的汽液平衡数据进行了关联,得到了相应的模型参数。用6组文献报道的水-醋酸体系的NRTL模型参数、4组水-N-甲基吡咯烷酮体系的模型参数及关联得到的醋酸-N-甲基吡咯烷酮体系的模型参数对三元体系的汽液平衡数据进行了预测,筛选出9组较佳的模型参数,获得了较优的预测结果。     

碳酸二甲酯-碳酸二乙酯-甲醇三元体系相平衡数据的推算

采用双循环汽液平衡釜测定了常压下碳酸二甲酯-碳酸二乙酯、碳酸二甲酯-甲醇、碳酸二乙酯-甲醇三组二元体系的汽液平衡数据,实验数据经Herington面积积分法检验符合热力学一致性。用Wilson模型分别对实验数据进行了关联,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,二者符合良好。利用二元体系的汽液平衡数据,由Wilson方程推算了碳酸二甲酯-碳酸二乙酯-甲醇三元体系的汽液平衡数据。为建立碳酸二乙酯和碳酸二甲酯、甲醇的精馏分离数学模型提供了基础数据。     

叔丁醇-异丙醇-水汽液平衡数据的测定及关联

采用单级循环汽液平衡釜测定常压下叔丁醇、异丙醇和水体系中的二元和三元的汽液平衡数据,并对其进行微分检验法热力学一致性校验;分别以WILSON,NRTL,UNIQUAC方程为相平衡模型,采用最小方差法对二元体系数据进行关联,确定模型参数;采用3对二元体系模型参数对三元体系的汽液平衡数据进行关联,比较汽液平衡数据的测定值与计算值,确定适宜的相平衡模型。文中为萃取精馏分离叔丁醇、异丙醇和水的混合液提供基础数据。     

三元体系中汽液平衡的盐效应

本文采用Otsuki-Williams式汽液平衡釜测定了甲酸-乙酸-水体系及甲酸-乙酸-水-醋酸钠体系在98.66kPa下汽液平衡数据.醋酸钠的浓度为1mol/kg溶剂.结果表明,醋酸钠不仅对体系起化学作用,也起物理化学作用.它涉及到了盐溶、盐析和盐效应的不规则现象.     

低浓度下己内酰胺-水-硫酸铵-苯体系的液液平衡问题

介绍了在己内酰胺废水中萃取回收己内酰胺的过程中，测定了4套己内酰胺—水—硫酸铵—苯体系的液液平衡数据(水相己内酰胺质量分数小于13％)。实验结果表明，用苯从废水中萃取回收己内酰胺时，pH在2～5．7范围内，pH值升高对回收有利。同时提出了一个简单的关联式并成功地关联上述平衡数据，已用于萃取塔的设计计算。     

Measurement and correlation of the solubility of sodium acetate in eight pure and binary solvents

The knowledge of solubility of a salt in either the pure solvent or blend solvent is of great importance for studying or operating the crystallization, extraction, and distillation processes. The solubility of sodium acetate (NaAc) in four pure solvents (water, ethanol, acetic acid and 2,2,2-trifluoroethanol) and four binary solvents (water–ethanol, water-acetic acid, acetic acid–ethanol, and acetic acid-ethyl acetate) were measured by using the laser dynamic method at temperatures from 288.15 K to 338.15 K at 0.1 MPa. The results showed that the solubility of NaAc was influenced by either the solution temperature or solvent composition. The aqueous sodium acetate solution possessed the maximal solubility under the experimental conditions. The solubility of NaAc in 2,2,2-trifluoroethanol was found to be decreased with the increase of the solution temperature. While, the solubilities of NaAc in other seven solvents increased as the solution temperature was elevated. Besides, five correlation models, including the van't Hoff model, modified Apelblat model, Yaws model, λh model, and modified Apelblat-Jouyban-Acree model were used to correlate the solubility data of those sodium acetate solutions with acceptable deviation, respectively. Finally, van't Hoff analysis method was selected to analyze the change law of thermodynamic properties of a salt during the dissolution process.     

Ni-P-纳米TiO_2化学复合镀镀液稳定性研究

在确定纳米TiO2超声分散工艺的基础上,采用正交试验和单因素比较法,系统研究了镀液配比、pH值、温度、PbCl2和纳米TiO2加入量对Ni-P-纳米TiO2化学复合镀镀液稳定性的影响。研究结果表明:镀液的配比、pH值、温度对镀液稳定性均有影响,其影响的显著性顺序是:pH值小于乳酸浓度小于温度小于镍磷比小于乙酸钠浓度的影响;PbCl2的加入可使镀液的稳定性明显提高,而纳米TiO2的加入对镀液的稳定性几乎没有影响;推荐Ni-P-纳米TiO2化学复合镀采用的镀液为:x(Ni2+/H2PO2-)=0 4,ρ(乳酸)=34g/L、ρ(乙酸钠)=4g/L、ρ(PbCl2)=0 0010g/L、ρ(TiO2)=4g/L。     

不同质量分数乙醇、乙酸钠溶液对双乙酸钠结晶过程影响

为提高双乙酸钠(SDA)的产品质量,考察了温度、溶剂组成、乙酸钠含量等条件对SDA溶解性的影响,采用动态法测定了SDA在不同质量分数乙醇-水、乙酸钠-水混合溶剂中的溶解度,并测定了SDA在纯水和质量分数为0.799 6(w1=0.799 6)的乙醇溶液中的介稳区。结果表明,SDA易溶于水,微溶于乙醇,随乙醇质量分数增加,SDA溶解度降低愈加显著,且在w1=0.799 6的乙醇溶液中降低最为明显;随产物中乙酸钠含量增加,SDA溶解度逐渐减小,且在质量分数为0.083 2乙酸钠溶液中降低幅度最大;在300~315 K范围内,w1=0.799 6的乙醇溶液对SDA和乙酸钠有明显的分离效果;SDA的介稳区宽度在纯水中随温度升高逐渐变窄,而在w1=0.799 6的乙醇溶液中受温度影响变化小,且介稳区宽度较纯水中窄。因此,在SDA结晶中,可采用w1=0.799 6的乙醇溶液结晶分离SDA,且过饱和浓度需控制在介稳区内。     

Electron Emission from Barium Strontium Titanate Ceramics

This paper focuses on understanding the influence of materials' properties on the ferroelectric electron emission. Ferroelectric ( x =1.0 and 0.8) and paraelectric ( x =0.67 and 0.5) compositions of barium strontium titanate (Ba _x Sr_{(1− x )}TiO₃) system were chosen for study based on their different ferroelectric and dielectric properties. Similar emission current waveforms were obtained from four compositions with negative triggering voltage applied to the rear electrode of the samples. It was difficult to explain the experimental results using the spontaneous polarization-switching model. The mechanism of electron emission from Ba _x Sr_{(1− x )}TiO₃ ceramics was ascertained to surface plasma emission.     

色谱斜率法测过量自由焓之模型参数的研究

研究了色谱测定(σγ/σx)_(x=0)的两种公式——修正的Kikic-Renon公式及Valentin-Guiochon公式,实测了29个二元系的γ_1~∞,分别按两种公式测定(σγ/σx)_(x=0),求取两参数过量自由焓模型参数,进而预测全浓度范围汽液平衡,得到了较为满意的结果.对Valentin-Guiochon公式合理简化,提出了一个较为简便的(σγ/σx)_(x=0) 公式.利用Gmehling等汇编的56个含醇及含水二元系γ_1~∞数据,直接计算该公式的(σγ/σx)_(x=0)之值,进而推算过量自由焓模型参数,并预测汽液平衡.又用气液色谱测定了各种含有极性与非极性组分、挥发与难挥发组分的不同类型43个二元系的γ_1~∞值,按上述方法预测全浓度范围汽液平衡,与文献中已发表的汽液平衡数据比较,结果都符合良好.最后,讨论了三种斜率公式各自的适用范围和两参数过量自由焓模型转化为单参数模型的一般方法.     

Growth of BA(TI1-xZRx)O3 single crystal fibers by laser heated pedestal growth technique

Ba(Ti_1-xZr_x)O₃ (x = 0.15 and 0.2) single crystal fibers were grown by the laser heated pedestal growth (LHPG) technique. The XRD results show that the grown crystals are of single phase. Temperature dependence of dielectric permittivity, room temperature hysteresis loops and strain were measured. A broad permittivity peak was observed with the temperature of the dielectric constant maximum T_m ≌ 339 K for x = 0.15, and T_m = 310 K for x = 0.2. The data were in agreement with those of corresponding ceramics, indicating that the compositions of the single crystals were similar to those starting stoichiometry (ceramics). The remnant polarization of 8.5 and 4.0 μC/cm² was obtained for x = 0.15 and 0.2, respectively. The strain level of ~0.065% and high field d₃₃ of ~ 130 pC/N for x = 0.15 were obtained.     

二溴苯三元物系固液平衡测定与正规溶液模型

采用差示扫描量热法,通过对一系列"拟二元"物系固液平衡数据的测定,得到了邻二溴苯、间二溴苯和对二溴苯三元物系的固液平衡数据.实验结果表明本物系为简单低共熔型,其低共熔摩尔分数组成和温度分别为:邻二溴苯(x1) 间二溴苯(x2) 对二溴苯(x3),x1=0.4259,x2=0.5345,x3=0.0396,Tcu=238.5 K.文中绘制出了其相应的低共熔三元固液平衡相图,并采用正规溶液模型,利用二元溶液的三个相互作用参数对实验数据进行了关联,温度均方根偏差仅为1.32 K,说明正规溶液模型适用于上述弱极性异构体三元物系固液平衡的计算.     

二溴苯物系固液平衡测定与正规溶液模型

采用差示扫描量热法测定了邻二溴苯与间二溴苯、对二溴苯与间二溴苯和对二溴苯与邻二溴苯的3个二元固液平衡数据,同时绘制出相应的简单低共熔型二元相图。各物系低共熔摩尔分数组成和温度分别为：邻二溴苯(x) 间二溴苯(1-x),x=0.4485,t=240．4K;对二溴苯(x) 间二溴苯(1-x),x=0.1002,T=260.9K：对二溴苯(x) 邻二溴苯(1—x),x=0.1306,T=272.3K。采用单参数正规溶液模型计算,温度均方根偏差不大于1.1K,说明正规溶液模型适用于上述弱极性异构体物系固液平衡计算．     

Formation and Structural Characterization of 1:1 Ordered Perovskites in the Ba(Zn1/3Ta2/3)O3–BaZrO3 System

The phase stabilities in the(1−x)Ba(Zn_1/3Ta_2/3)O₃ (BZT)-xBaZrO₃(BZ)system have been investigated using samples prepared by the mixed oxide method. The substitution of Zr⁴⁺destabilizes the 1:2 cation ordering in BZT and pro-motes the formation of a cubic, 1:1 ordered structure with a doubled perovskite repeat. The homogeneity range of the 1:1 phase extends from x = 0.04 to approximately x = 0.25; substitutions beyond this range stabilize a disordered perovskite. The limits of stability of the 1:1 ordering coin-cide with compositions previously found to exhibit anoma-lies in their dielectric loss. The range of homogeneity is consistent with a "random layer" model for the 1:1 ordered "Ba{β';_1/2β^1/2}O₃" structure. In this model the B× positions are assumed to be occupied exclusively by Ta⁵⁺, and the b× sites by a random distribution of Zn₂₊, Zr₄₊, and the remaining Ta 5+ cations. The validity of the model, where the ordered solid solutions can be represented by Ba{[Zn_{2− y /3}Ta_{(1−2 y )/3}Zr y ]_1/2[Ta]_1/2}O₃(y =2x)was con-firmed by Rietveld refinements conducted using data col-lected with a synchrotron X-ray source.