电解质活度系数与溶剂化数

采用扩展的Debye-H(?)ckel方程来表示溶剂化离子的活度系数,并应用数学处理消去渗透系数(?),从而建立了一个只与溶剂化数h有关的单参数活度系数公式.经对48个体系的处理,表明本文所建立的单参数活度系数公式具有良好的适用性.     

NaCl在混合溶剂(DMF-H2O)中热力学性质的研究

应用钠离子选择性电极和Ag-AgCl电极组成可逆电池,通过测定电池的电动势,应用Debye-Hückel极限公式,求得不同温度下NaCl在混合溶剂(DMF-H2O)中的活度系数(γ±),计算了NaCl在混合溶剂(DMF-H2O)中的相对偏摩尔自由能,并据电解质溶液的溶剂化理论对NaCl溶液的活度系数及相对偏摩尔自由能的变化规律进行了初步的讨论。     

对苯二甲酸结晶热力学研究

在291.65—369.15 K下用平衡法测定了对苯二甲酸在醋酸体积分数为1.000、0.895、0.791和0.688时的醋酸水溶液中的溶解度。根据固液平衡理论建立了对苯二甲酸的溶解度模型,用溶液化学理论导出了对苯二甲酸的活度系数与溶剂化平衡常数的关系式,并建立了估算对苯二甲酸溶剂化平衡常数的关系式。应用实验得到的溶解度数据估算了对苯二甲酸的溶解热、混和热、活度系数、溶剂化平衡常数和溶剂化过程中氢键的生成焓,为对苯二甲酸的工业生产提供了热力学数据。     

混合液闪点的计算方法

提出根据液体混合物种类,采用适当的活度系数公式计算混合液闪点的方法,活度系数公式中的参数可由气液平衡数据或由文献得到。     

聚二甲基硅氧烷/溶剂体系气液平衡研究

采用气液色谱法测定了聚二甲基硅氧烷（ＰＤＭＳ）和９种溶剂在５８～１８０℃范围内,７个不同温度下无限稀溶剂活度系数和Ｆｌｏｒｙ－Ｈｕｇｇｉｎｓ相互作用参数。应用ＵＮＩＦＡＣ和ＵＮＩＦＡＣ－ＦＶ模型对ＰＤＭＳ／烃溶剂体系无限稀溶剂活度系数进行了估算。结果表明,ＵＮＩＦＡＣ－ＦＶ模型能较好地预测ＰＤＭＳ／烃溶剂体系无限稀溶剂活度系数。     

抽提甲基环戊烷及精制正己烷的分离研究

测定了正己烷和甲基环戊烷在七种溶剂中的无限稀释活度系数,比较溶剂的选择性和溶解性的差别。分析温度对邻苯二甲酸二丁酯分离能力等参数的影响;以Ｗｉｓｏｎ方程为汽液平衡模型,模拟不同温度下,正己烷的化和甲基环戊烷回收的分离结果。     

烃类溶质无限稀活度系数的测定和关联

研究溶质进样量、溶剂(固定液)涂复量和载气流速(柱压降)等对色谱法测定溶质无限稀活度系数的影响,提出用通用型气相色谱仪准确测定溶质无限稀活度系数的实验方法,测定了正戊烷、正己烷、正庚烷、环己烷、苯和甲苯等烃类溶质在角鲨烷和正十八烷两种溶剂中,在30℃、50℃和70℃及大气压力下的无限稀活度系数,提出关联溶质无限稀活度系数的基团贡献模型,并定出CH_3、CH_2、CH、CYCH_2、ARCH和ARC基团的参数,用此模型进行无限稀活度系数和非无限稀活度系数的预测,其结果比ASOG模型要好。     

利用变阱宽方阱链流体状态方程计算1：1电解质溶液热力学性质

将变阱宽方阱链流体状态方程拓展到1：1强电解质水溶液热力学性质的计算中,通过关联溶液的平均离子活度系数和溶剂的渗透系数得到了22种离子的链节直径和方阱能量参数,40余种电解质溶液的平均离子活度系数和溶剂渗透系数的总平均相对偏差分别为6.03%和5.83%。计算结果表明,建立的电解质型状态方程可以满意预测电解质溶液的密度和宽广温度下溶液的蒸气压,总体平均相对偏差分别为0.22%和4.69%。进一步说明模型参数的可靠性。     

非水电解质浓溶液的热力学研究(Ⅰ)——用缔合模型关联、推算298.15K时HCL甲醇浓溶液的活度系数

利用HCl在甲醇中稀溶液的活度系数,通过Pitzer的缔合模型,关联出298.15K HCl在甲醇中的缔合常数Kx=1.7×10~2,然后利用HCl在甲醇中浓溶液的活度系数关联出近程作用单参数,进而推算溶剂甲醇的活度系数及溶液总压,均得到满意的结果,说明HCl甲醇浓溶液的热力学关联必须考虑HCl的部分离解效应。     

用气液色谱研究含乙二醇体系的盐效应

用气液色谱法测定了甲醇、乙醇、正丙醇、正丁醇、丙酮及水在含盐(乙酸钾、硝酸钾、硫氰酸钾或碘化钾)乙二醇中无限稀释条件下的活度系数;含盐溶剂的选择度及盐效应参数。本文讨论了盐对活度系数的影响,提出了一些溶盐选择的一般规律。     

四丁基氟化铵在DMF中的活度系数测定

采用电导法测定了298.15~343.15 K下四丁基氟化铵（TBAF）在DMF中的电导率,计算出TBAF在DMF中的摩尔电导率;根据Kohlrausch规则,采用外推法求出TBAF在DMF中的无限稀释摩尔电导率;采用DebyeHücker和Osager-Falkenhangen公式计算出TBAF在DMF中的平均活度系数,并讨论了TBAF电解质溶液活度系数的影响因素。结果表明,其活度系数随溶液浓度的增大和温度的升高而减小。     

New formula for calculating time to ignition of semi‐infinite solids

An analytical closed form formula is presented for explicitly calculating time to reach ignition temperature of semi‐infinite solids exposed to constant incident radiation and gas temperature as for example in the cone calorimeter. The non‐linear boundary condition due to the emitted radiation from the surface being proportional to the surface temperature raised to the fourth power according to the Stephan–Boltzmann law is accurately considered. The formula works for a wide range of the parameter values like the thermal inertia of the solid, the emissivity of the exposed surface and the convective heat transfer coefficient. They are all assumed constant. The new formula contains a single constant coefficient, which has been derived by comparing results obtained by accurate numerical finite element simulations using two different codes, comsol and TASEF , as well as calculations based on a Duhamel superposition scheme. Thus, the formula can be classified as semi‐empirical. It offers a simple approximate solution of a non‐linear problem that requires cumbersome numerical calculation methods to obtain more exact results. Any exact analytical solution is not available. The new method is carefully verified by comparisons with numerical solutions. However, as it is an analysis of well‐defined theoretical methods, any validation and comparisons with test data are not required and has therefore not been made.In comparison with other similar approximation formulas found in the literature, the accuracy as well as simplicity of applying the new formula is outstanding. Copyright © 2015 John Wiley & Sons, Ltd.     

A novel formula for the quality factor calculation for the multiphase microwave dielectric ceramic mixtures

Microwave dielectric ceramics are pillar materials in the microwave applications, for example, resonators. However, because most ceramics possess non-zero temperature coefficients, two or more ceramics, with temperature coefficient of opposite signs, are always mixed as a multiple phase system to obtain a zero temperature coefficient ceramic. While the dielectric constant can be calculated by the Maxwell-Wagner based formula, the quality factor (Q) is usually hard to be precisely calculated by the conventional method. In this paper, basing on the classical dispersion theory, we derive a new formula for the Q calculation for the ceramic mixtures. The deviation between the calculated and reported Q, of several typical ceramic systems, is around ±5%, for the example of two phases ceramic mixtures.     

粉煤灰品质评价方法研究

根据粉煤灰胶凝系数概念,通过试验研究,建立了细度、需水量比和烧失量三参数的胶凝系数计算模型。在此基础上给出了以胶凝系数评价粉煤灰品质的新方法,并与国内外其它评价方法作了比较。     

输气管道二元气体混合长度变化规律分析

运用模拟试验、平推流建模、数值计算与现场数据对比等手段,对输气管道二元气体的混合系数和混合长度进行了研究。在平推流模型求解过程中,为提高计算精度,将Taylor公式中的摩擦系数进行了修正。通过国内外10条天然气管道气体置换实例的对比分析,可知粗糙度对混合系数影响很小。同时,采用不同方法计算得出了二元气体的混合系数,Taylor-CW得出的混合系数平均比Taylor公式大1.1倍。在大管径、长距离、高流速的置换工况下,GR I(美国天然气研究所)公式混合长度计算结果与实测值误差较小。而对于小管径、短距离或者低流速的工况,用Taylor-CW公式能获得更真实准确的结果。     

Geometrical properties of porous media

The use of the coefficient characterizing the pore structure of the body in the Darcy formula is analyzed. It is shown by several examples that the translucence factor rather than the porosity factor should be used in the Darcy formula. The relations between these two factors are established by the introduction of a new linear characteristic, namely, the discontinuity factor for different types of porous body.     

山谷型垃圾卫生填埋场渗滤液水量计算

垃圾填埋场渗滤液水量是工程设计中的一个重要参数，新的设计规范要求填埋区渗透系数小于10^-7cm／s，由于目前国内外尚无成熟的计算方法，设计院往往采用防渗要求前的经验公式，对山谷型垃圾填埋场渗滤液水量计算，误差很大。作者提出一个没有经验参数的计算公式，可以精确计算，并对减少山谷型垃圾填埋场渗滤液水量的工程设计提出建议。     

圆筒式磁力传动器磁扭矩计算的一种新方法

在等效磁荷理论的基础上,运用磁荷积分法对圆筒式磁力传动器的磁扭矩进行数学建模推导得到一种新的磁扭矩计算公式,通过试验验证了该磁扭矩计算公式的正确性。通过与其他常用磁扭矩计算方法的比较,该算法平均相对误差较高斯定理求解法和经验公式求解法的小,且不需用试验确定经验系数。     

Correlation of the mean activity coefficient of aqueous electrolyte solutions using an equation of state

Accurate calculation of thermodynamic properties of electrolyte solution is essential in the design and optimization of many processes in chemical industries.A new electrolyte equation of state is developed for aqueous electrolyte solutions.The Carnahan–Starling repulsive model and an attractive term based on square-well potential are adopted to represent the short range interaction of ionic and molecular species in the new electrolyte EOS.The long range interaction of ionic species is expressed by a simplified version of Mean Spherical Approximation theory(MSA).The new equation of state also contains a Born term for charging free energy of ions.Three adjustable parameters of new e EOS per each electrolyte solution are size parameter,square-well potential depth and square-well potential interaction range.The new e EOS is applied for correlation of mean activity coefficient and prediction of osmotic coefficient of various strong aqueous electrolyte solutions at 25 °C and 0.1 MPa.In addition,the extension of the new e EOS for correlation of mean activity coefficient and solution density of a few aqueous electrolytes at temperature range of 0 to 100 °C is carried out.