1己基3甲基咪唑碘盐与分子溶剂二元体系密度和黏度

本研究系统地测定了288.15~323.15 K条件下,1己基3甲基咪唑碘盐([Hmim][I])分别与甲醇(CH 3OH)、二甲基亚砜(DMSO)和异丙醇(IPA)组成的二元混合溶液体系在全浓度范围内的密度和黏度。通过密度和黏度数据分别计算了二元混合溶液体系的过量体积(V E)与黏度偏差(Δη),采用Redlich Kister方程对V E、Δη随溶液组成的变化进行回归,获得方程参数。结果表明:温度升高,二元混合溶液体系的密度和黏度均降低,随着[Hmim][I]含量增加,二元混合溶液体系密度和黏度均增加。V E和Δη呈负偏差,不同分子溶剂对V E和Δη的影响较大。溶剂的分子大小对二元混合溶液体系的V E影响较大,Δη受到分子溶剂分子体积、分子极性和介电常数等综合因素的影响,导致CH 3OH对其影响最大,IPA其次,DMSO最小。

MathCAD在相平衡计算中的应用

MathCAD具有接近板书风格的语言且计算功能强大,在处理化工热力学中的相平衡问题时十分方便,且能十分清晰直观地反映出相平衡模型计算的推演过程,将复杂的相平衡计算问题简单化后直接搬上课堂,能大大提高课堂教学效果。本文通过两个实例,说明如何利用MathCAD软件来处理常见的相平衡计算问题,并对计算结果进行了分析,证明了计算结果的可靠性。

二甲苯异构体与八甲基环四硅氧烷二元混合物在298.15K的密度、表面张力和黏度

测定了八甲基环四硅氧烷(D4)分别与邻二甲苯、间二甲苯和对二甲苯组成的二元混合物在298.15K下全浓度范围内的密度、表面张力和黏度,计算了表面张力偏差和黏度偏差,并用Redlich-Kister多项式方程对实验数据进行了拟合。结果表明,上述3个二元体系的表面张力偏差和黏度偏差均为负值。

六硝基茋在硝酸中的溶解度测定及关联

采用激光监测技术,测定了25℃下六硝基茋在不同浓度硝酸中的溶解度,用(CNIBS)/Redlich-Kister经验方程对实验数据进行了关联。结果表明六硝基茋在硝酸中的溶解度随硝酸浓度的增大而增加,用(CNIBS)/Redlich-Kister方程预测的溶解度值与实验值有较好的吻合。

Mg-Er二元体系的热力学评估

采用CALPHAD(CALculation of PHAse Diagram)方法,对Mg-Er二元体系重新进行了热力学评估。用Redlich-Kister模型对溶体相(Liquid,HCP_A3和BCC_A2)进行描述。金属间化合物Mg_(24)Er_5和Mg_2Er存在一定的成分区间,并分别用双亚点阵模型表示:Mg_(24)(Mg, Er)_5和(Mg, Er)_2(Mg, Er)_1。化合物MgEr的成分区间较窄,作为化学计量化合物处理。基于文献评估的实验数据,获得一套自恰的Mg-Er二元体系的热力学参数。

二元系热力学性质解析计算表示式的改进形式

提出二元系热力学性质的Ｍａｒｇｕｌｅｓ展开式，Ｒｅｄｌｉｃｈ－Ｋｉｓｔｅｒ展开式和Ｌｇｅｎｄｒｅ展开式的改进形式。该式具有收敛性强和系数间不相关的特点。

Thermodynamic investigation of ZrO_2-BaO system

Thermodynamic description of ZrO2-BaO system was developed using the available experimental information. Special attention was paid to the modelling of the perovskite phase BaZrO3 by a temperature-dependent polynomial to fit the experimental thermodynamic properties. The liquid phases, CSS (cubic ZrO2 solid solution) and TSS (tetragonal ZrO2 solid solution) were modelled with Redlich-Kister formula. The compounds Ba2ZrO4 and Ba3Zr2O7 were treated as stoichiometric phases and the BaOSS and MSS (halite BaO and monoclinic ZrO2 solid solutions) were treated as pure compounds. Comparisons between the calculated and the measured phase diagram as well as the thermodynamic quantities indicate that the most reliable experimental information is satisfactorily accounted for by the present thermodynamic calculation.

Effect of Dissolved Cadmium Chloride and Ammonium Chloride Salts on the Enthalpy of Mixing of the Methanol＋Benzene System at 303.15 K

The effect of two dissolved inorganic salts,cadmium chloride CdCl2 and ammonium chloride NH4Cl,on the excess enthalpy of mixing(HE) of the binary system methanol + benzene measured at 303.15 K using an iso-thermal displacement calorimeter with vapor space is investigated in the present work. Compared to the salt-free system,a decreasing trend in the endothermicity of HE values is significant with the addition of CdCl2 salt but the decrease in the HE values is insignificantly smaller with the addition of NH4Cl salt. The experimental values of the enthalpy of mixing are fitted into a Redlich-Kister equation and the deviations in the values and the parameters are reported. The importance of the solute-solvent interactions and the solvent-solvent interactions are demonstrated from the increasing excess enthalpy of mixing values in the positive direction with the increase of salt concentration.

函数曲线之间符合程度的评价

在科学实验及理论研究中常常需要对某一函数在一定自变量范围内的不同来源的数据进行比较与评价。本文提出了一种比较实验曲线或理论曲线间符合程度的方法———积分法 ;对于多项式和Redlich Kister方程形式的曲线推导出了标准偏差计算公式 ;选取不同文献来源的环己烷 苯体系超额体积实验值 ,对它们在全浓度范围内的总体符合程度进行了评价。

RE_2O_3-SiO_2(RE=La,Ce)相图及其相关热力学研究

鉴于RE_2SiO_5、RE_(4.67)Si_3O_(13)(RE=La、Ce)等稀土硅酸盐热力学数据的缺失,通过比较分析后采用较准确的Carvalho经验式、Binnewies熵值相加法、Neumann-Kopp定律、Kubaschewski法计算得到了稀土硅酸盐的标准生成焓、标准熵、C_p(298.15 K)、C_p(T)等热力学数据,对稀土硅酸盐的热力学数据进行了补充和完善。采用Redlich-Kister表达式得到了较为准确的La_2O_3-SiO_2相图,在此基础上首次对Ce_2O_3-SiO_2体系的相图进行了预测。

Chemical Composition Control of Non-Metallic Inclusions in High Alloy Steel Production Process

There is a close relation between the characteristics of products and the chemical composition control of inclusions in steelmaking process. Therefore, it is very important for a warranty of product’s characteristics to improve inclusion quality resulting in defective products. In the present work, the control technique of inclusions’ chemical composition is discussed thermodynamically based on the Redlich-Kister type polynomial to metallic solution and regular solution model to molten oxide solution. It is very effective for the precise chemical composition control of oxides to determine the concentration of deoxidizers based on the thermodynamic relation among dissolved deoxidizers and oxygen, because it is known that oxide inclusions are equilibrated with them in molten steel in the steel making process. High alloy steel production process was focused in the present work.

Dielectric relaxation studies of binary mixture of β-picoline and methanol using time domain reflectometry at different temperatures

Complex permittivity spectra of binary mixtures of varying concentrations of β-picoline and Methanol(MeOH)have been obtained using time domain reflectometry(TDR)technique over frequency range 10 MHz to 25 GHz at 283.15,288.15,293.15 and 298.15K temperatures.The dielectric relaxation parameters namely static permittivity(ε),high frequency limit permittivity(ε∞1)and the relaxation time(τ)were determined by fiting complex permittivity data to the single Debye/Cole-Davidson model.Complex nonlinear least square(CNLS)fiting procedure was carried out using LEVMW software.The excess permittivity(ε_(0)^(E))and the excess inverse relaxation time(1/τ)^(E) which contain information regarding molecular structure and interaction between polar-polar liqids were also determined.From the experimental data,parameters such as effective Kirkwood correlation factor(geff),Bruggeman factor(fB)and some thermo dynamical parameters have been calculated.Excess parameters were fitted to the Redlich-Kister polynomial equation.The values of static permittivity and relaxation time increase nonlinearly with increase in the mol-fraction of MeOH at all temperatures.The values of excess static permittivity(ε_(0)^(E))and the excess inverse relaxation time(1/τ)^(E) are negative for the studied β-picoline MeOH system at all temperatures.

Dielectric studies of binary mixtures of ethylene glycol mono phenyl ether with 1-butanol at different temperatures

Static permittivity(ε),refractive index(n)and density(ρ)of binary mixtures of ethylene glycol mono phenyl ether(EGMPE)with 1-butanol(1-BuOH)over the entire range of mole fraction and at temperatures(T=303:15,313.15 and 323.15 K)have been measured.From the experimental data,parameters such as excess static permittivity(ε^(E)),excess permittivity at optical frequency(ε^(E)_(∞)),effective Kirkwood correlation factor(g^(eff)),corrective Kirkwood correlation factor(g^(f))and Bruggeman factor(f^(b))have been calculated to obtain qualitative and quantitative information about the complex formation through H-bond in binary system.In order to predict the static permittivity of polar–polar binary mixtures six mixing rules were applied and for refractive index five mixing rule were applied.Experimental results of permittivity(ε)and refractive index(n)are compared with those obtained from theoretical calculations.Excess parameters were fitted to the Redlich–Kister type polynomial equation.