Density,Viscosity, and Surface and Interfacial Tensions of Mixtures of Water + <Emphasis Type="Italic">n</Emphasis>-Butyl Acetate + 1-Propanol at 303.15 K and Atmospheric Pressure

Experimental densities, viscosities, and surface and interfacial tensions have been measured at 303.15 K for liquid mixtures of water + n-butyl acetate + 1-propanol. The excess molar volume, V ^E, viscosity, η, and surface tension, γ, were calculated and rational functions due to Myers and Scott, and Pando et al. were used to describe the composition dependence of these properties. The viscosity, η, of the mixtures was correlated using a theoretically based method developed from the Eyring theory using the above-mentioned rational functions to express the excess Gibbs energy of activation for viscous flow, G ^≠E. The UNIMOD model based on the Eyring theory was used to correlate the viscosity of the binaries and to predict the same property for ternary mixtures. To describe the above-mentioned properties of the ternary system, binary pair additivity and some empirical models were considered. The methods of Fu et al. and Li et al. were used to correlate the binary surface tension and also to predict the ternary behavior. The interfacial tension was correlated by the Li and Fu method.     

Temperature Dependence of the Volumetric Properties of Binary Mixtures Containing Polyethers and 1-Propanol

Excess molar volumes (V ^E _m ) were measured at 288.15, 298.15, and 308.15 K and atmospheric pressure as a function of composition with a continuous dilution dilatometer for the binary mixtures of 1-propanol [CH₃CH₂CH₂OH] with glymes [CH₃O(CH₂CH₂O) _m CH₃, m=1,2,3, and 4]. With these results and other thermodynamic data from the literature, the following mixing quantities have been reported over the complete range of concentration or at equimolar concentration: , volume expansivity; ^E , excess volume expansivity; (V ^E _m /T) _P , and (H ^E /P) _T at 298.15 K. The Prigogine–Flory–Patterson theory (PFP) of liquid mixtures has been applied to estimate interaction, free-volume, and internal-pressure contributions to V ^E _m and to estimate the different mixing quantities for the mixtures. The calculated values using the PFP theory were then compared at 298.15 K with the experimentally obtained results. The PFP theory predicts excess volume V ^E _m values rather well, while the calculated value of (V ^E _m /T) _P and (H ^E /P) _T by using the Flory theory show general variation with the chain length of the glyme. The (V ^E _m /T) _P and (H ^E /P) _T show deviations between theoretical and experimental values that are slightly larger in systems with lower glyme.     

Prediction of simultaneous adsorption of Cu(II) and Pb(II) onto activated carbon by conventional Langmuir type equations

Removal of Cu(II) and Pb(II) by adsorption onto activated carbon was examined in single- and binary-component aqueous solutions representative of contaminated solutions containing heavy metals. Reversibility of adsorption of the heavy metals on the activated carbon was evaluated by desorption experiments. The number of the maximum adsorption sites and adsorption equilibrium constants of Cu(II) and Pb(II) were estimated by the results of single-component systems assuming the Langmuir adsorption model. The adsorption sites per gram of activated carbon resulted in similar values for Cu(II) and Pb(II) from the isotherms. The adsorption constant for Pb(II) was nearly 1.8 times greater than that of Cu(II). Rate constants of adsorption and desorption were also estimated from the kinetic analysis. Using the single set of common parameters obtained from the single-component systems, the experimental results for a binary-component system were quantitatively predicted. Competitive adsorption of Cu(II) and Pb(II) on the same adsorption sites was confirmed by both experimental and predicted results of adsorption in the binary mixture.     

Liquid Viscosity of Binary Mixtures of Methanol with Ethanol and 1-Propanol from 273.15 to 333.15 K

The liquid viscosities and densities of two binary mixtures of methanol with ethanol and 1-propanol were measured in the temperature range from 273.15 to 333.15 K with a capillary viscometer and a glass pycnometer, respectively. The uncertainties in the measured viscosities were estimated to be smaller than 1.3%. The experimental viscosity values could be fitted to the Mertsch and Wolf equation within 2%.     

Grazing incidence X-ray diffraction study of the tilted phases of Langmuir films: Determination of molecular conformations using simulated annealing

We have analyzed grazing incidence X-ray diffraction (GIXD) data from condensed phases of Langmuir films of long-chain fatty acids at the air-water using a new method consisting in a careful extraction of the structure factors followed by fitting of molecular parameters using simulated annealing. We show that the information contained in GIXD spectra is enough to obtain near-atomic structural information. In particular, we directly determine the orientation of the chain backbone planes and of the carboxylic headgroups, and we evaluate chain conformation defects.     

改进GM(1,1)模型在环境噪声预测中的应用

从传统GM（1，1）预测模型构造原理出发分析其存在的理论缺陷，此模型适用于具有较强指数规律的序列。只能描述单调变化过程，而且预测数据序列中出现连续两个相等值时将使得α等于0，会使预测数列发散致使预测失效。采用平均斜率的概念计算α（k）序列，并利用MATLAB编程实现数据处理。广州市环境噪声污染数据计算表明，新方法有满意的拟合和预测效果，从而为提高建模精度提供了新的途径。     

Excess Molar Isentropic Compressibilities,Excess Molar Volumes,and Excess Sound Speeds of the 1-Propanol + Diethyl Ether + 1-Octanol Ternary Mixture and Constituent Binary Mixtures at 298.15 K

The sound speeds and densities of the 1-propanol + diethyl ether + 1-octanol ternary mixture and constituent binary mixtures, 1-propanol + diethyl ether, 1-propanol + 1-octanol, and diethyl ether + 1-octanol, have been measured at 298.15 K as a function of composition. Isentropic compressibilities, molar isentropic compressibilities, excess molar isentropic compressibilities, excess molar volumes, and excess sound speeds have been calculated from the experimental density and sound speed data. Excess molar volumes, excess molar isentropic compressibilities, and excess sound speeds of the binary mixtures were fitted to the Redlich–Kister equation. By using the free length theory (FLT), Schaaff’s collision factor theory (CFT), Nomoto’s relation (NR), Van Deal’s ideal mixing relation (IMR), and Junjie’s relation (JR), sound-speed values of the investigated mixtures were calculated. These values were compared with the experimental sound-speed results.     

组合模型对我国软件人才预测的应用实例

随着软件行业的快速发展,软件人才已经成为该行业重要的战略资源.研究目的便是通过对软件人才预测进行研究,使政府部门以及软件企业更好地了解和管理软件人才.根据人才预测的特点,引用灰色GM(1,1)模型预测法和线性回归预测法,利用组合模型技术建立了需求预测综合模型.应用此模型对我国未来5年软件人才需求进行了预测.     

露采爆破效果评价的灰色模型及其应用

露采爆破效果的优劣是由多项指标控制的，是一个综合评价问题。本文运用灰色系统理论建立了评价灰色模型，并应用该模型来评价露采爆破效果。     

An automatic technique for measuring the surface tension of liquid metals

A methodology for automatic measurement of surface tension of liquid metals is presented. The procedure involves the digitization of a television image of a drop of the liquid metal, image processing to obtain the real coordinates of the drop profile, and a final computation of the drop surface tension by a nonlinear regression technique. The method is faster and more reliable than other classical methods, and yields results that are reproducible and as precise as those obtainable by non-automatic procedures. An important feature of this approach is that it can be used for metallurgical tests to check the quality of an alloy during its production, or to provide surface tension data in non-equilibrium processes.     

Speeds of Sound and Isentropic Compressibilities in Binary Mixtures of 2-Propanol with Several 1-Alkanols at 298.15 K

Speeds of sound and densities of 2-propanol +1-propanol, 2-propanol + 1-butanol, 2-propanol + 1-octanol, and 2-propanol + 1-hexanol have been measured over the entire composition range at 298.15 K. Speeds of sound of the binary mixtures have also been estimated from free length theory (FLT), collision factor theory (CFT), and Nomoto’s relation (NR) and have been compared with experimental speeds of sound. The isentropic compressibilities, molar isentropic compressibilities, excess molar isentropic compressibilities, and excess speeds of sound have been calculated from experimental densities and speeds of sound. Excess molar isentropic compressibilities and excess speeds of sound of the binary mixtures were fitted to the Redlich–Kister equation     

Plasma parameters in the vicinity of the quartz window of a low pressure surface wave discharge produced in O2

Plasma parameters in the vicinity of the dielectric window of a low density, microwave discharge produced in O₂ at 915 MHz are investigated by a spherical probe and optical emission spectroscopy while the microwave field distribution is measured by a spectrum analyzer. The electron energy distribution function is found to be strongly dependent on the position with respect to the slot antenna, exhibiting a group of energetic electrons at locations where the electric field and the optical intensity exhibit maximum values. The density of energetic electrons decreases sharply just a few cm away from the dielectric.     

超精密车削表面粗糙度预测模型的建立

介绍了一种利用回归分析法来建立单点金刚石刀具超精车削表面粗糙度预测模型的新方法，并通过建立的粗糙度预测模型，研究了铝合金超精密车削过程中切削速度，进给量和切削深度等参数对表面粗糙度的影响。通过实验分析表明：二次预测方程比一次预测方程更有效，而且适用范围比一次模型大。利用优化设计中的约束变尺度法对所建立的表面粗糙度预测方程进行了优化，可以实现对切削参数的优选，从而达到加工前在特定的条件下预测和控制表     

Study on the Interaction Coefficients in PR Equation with vdW Mixing Rules for HFC and HC Binary Mixtures

The Peng-Robinson equation of state with the van der Waals mixing rules was used to correlate vapor–liquid equilibrium (VLE) data for HFC/HC, HFC/HFC, and HC/HC binary mixtures. The interaction parameter k _ij was obtained for every binary mixture. It was assumed that k _ij has contributions from the two components, and each component has its own constant contribution factor k _i for the mixture, and the values of k _ij indicate the degree in difference of properties between the two components. Therefore, the interaction parameters k _ij is proposed as: k _ij  = k _i  − k _j . The values of the mixing factor k _i for Hydrofluorocarbons (HFCs) and Hydrocarbons (HCs), including propane, isobutane, n-butane, R23, R32, R125, R143a, R134a, R152a, R227ea R236fa, R236ea, and R245fa, were obtained by least-square fitting. In total, 39 refrigerant binary mixtures were analyzed on the basis of this method, and the results showed good agreement with experimental data. The overall average absolute deviations of pressure and vapor mole fraction are 1.3 % and 0.0089, respectively.     

聚乙烯拉伸应变速率的本构方程改进及运用

目的 对等密度、恒温条件下聚乙烯（PE）在不同应变率下的力学性能进行研究,改进原有本构方程的应变率项。方法 使用万能材料试验机,测量不同拉伸速率下PE的应力-应变曲线,并研究随着应变速率的增加,最大拉伸强度和断裂伸长率的变化趋势;基于Sherwood-Frost本构模型,对经典的热激活机制Seeger模型添加幂函数项,实现应变率与应变的耦合;基于最小二乘法,采用Matlab软件拟合本构模型参数,并将本构方程拟合结果与300,400,500 mm/min速率下的试验数据进行对比。结果 改进后的本构模型拟合数据与试验结果具有更高的吻合度,最大误差为8.12%,出现在300 mm/min的速度条件下。结论 随着拉伸速率的增加,PE材料的最大拉伸强度逐渐增加,断裂伸长率逐渐降低;改进应变率项后,本构模型具有更高的拟合精度,能够为有限元分析提供准确的材料参数。     

A numerical model for the dissolution of spherical particles in binary alloys under mixed mode control

A general numerical model is described for the dissolution kinetics of spherical particles in binary systems for any combination of first order reactions at the particle-matrix interface and long distance diffusion within the matrix. The model is applicable to both finite and infinite media and handles both complete and partial particle dissolution. It is shown that interfacial reactions can have a strong effect on the dissolution kinetics, the solute concentration at the particle-matrix interface and the solute concentration profile in the matrix.     

1-3-2型压电陶瓷/聚合物复合材料的理论模型

根据Chan的1-3型复合材料理论模型和Newnham的复合材料串并联理论,提出了一种用于计算新型1-3-2型压电陶瓷/聚合物复合材料的介电常数和压电常数的理论模型.并制备了一批1-3-2型压电复合材料样品,把理论模型的计算值与实际测量的材料参数进行了比较,结果表明两者符合较好,误差小于10%.     

Influence of platelet-activating factor,lyso-platelet-activating factor and edelfosine on Langmuir monolayers imitating plasma membranes of cell lines differing in susceptibility to anti-cancer treatment: the effect of plasmalogen level

Three structurally related but differing in biological activities single-chained ether phospholipids (PAF (platelet-activating factor) and lyso-PAF) and an anti-cancer drug (edelfosine (ED)) were investigated in Langmuir monolayers imitating natural membranes. The aim of the undertaken experiments was to study the influence of these lipids on monolayers mimicking plasma membranes of cell lines differing in susceptibility to the anti-cancer activity of ED, i.e. promyelocytic leukaemia cells (HL-60) and promyeloblastic leukaemia cells (K-562). As these cells differ essentially in the cholesterol/phospholipid ratio and plasmalogen concentration in the membrane, we have carried out systematic investigations in artificial systems of various compositions. The results for model leukaemia cell membrane were compared with data acquired for systems imitating normal leucocytes. Our results show that the level of plasmalogens significantly modulates the influence of the single-chained phospholipids on the investigated systems. The experiments confirmed also that the interactions of ether lipids with a model membrane of HL-60 cells (in biological tests sensitive to ED) have opposite character when compared with K-562, being resistant to ED. Moreover, the values of the parameters characterizing monolayers serving as membrane models (strength of interactions, monolayers fluidity and morphology) proved both sensitivity of these cells to ED and lack of their susceptibility towards PAF. Interestingly, it has been found that lyso-PAF, which is usually described as an inactive precursor of PAF, displays a stronger effect on HL-60 model membranes than ED.     

老年人心智模型研究及在交互设计领域的应用

目的 对面向老年人群的心智模型研究及其在信息交互设计领域的应用现状进行分析梳理,以对相关领域的理论研究与应用建立较为全面的认识。方法 基于文献可视化工具,对国内外2000—2020年收录的面向老年人群的心智模型研究及其主要应用文献进行收集、整理与可视化分析,通过代表性文献、