用径向分布函数及Lennard—Jones位能模型计算真实流体的PVT …

用顺序解析平衡法,结合Ｌｅｎｎａｒｄ－Ｊｏｎｅｓ（Ｌ－Ｊ）位能函数模型计算径向分布函数,然后直接代入统计热力学所给出的理论状态方程程序预测真实流体的ＰＶＴ性质。Ｌ－Ｊ位能模型参数由临界温度Ｔｃ和临界压力Ｐｃ确定。结果表明该方法能成功地预测非极性和弱极性纯流体的ＰＶＴ性质。当分子尺寸小于正己烷时,除临界温度附近之外,预测的饱和液体体积的平均相对误差一般小于５％,对于分子尺寸更大的流体,可应用象Ｋｉｈ     

共聚高分子体系的分子热力学模型

以共聚硬球链流体的分子热力学模型为基础，通过引入链节间方阱位能相互作用的贡献。建立了实际共聚高分子系统的分子热力学模型，对纯共聚高分子ＰＶＴ的关系结果，平均相对误差为０．２２％－０．８０％。     

应用WCA微扰理论推算非极性液体比热容的新方法

本文首次将统计热力学的Ｗｅｅｋｓ－Ｃｈａｎｄｌｅｒ－Ａｎｄｅｒｓｏｎ（简称ＷＣＡ）微扰理论应用于非极性液体定容比热容和定压比热容的推算，用一些液体的ｐ－ｖ－Ｔ实验数据拟合了理论中所用ＬＪ势能函数的势能参数，并提出一个通用关联式。本文方法具有通用性，在编制的计算程序中只需输入物质的临界温度、临界比容、偏心因子等就能算出相应的比热容，工程应用十分方便。     

形状因子对应态原理预测流体的热力学性质

采用形状因子对应态原理,由纯流体的蒸汽压和饱和汽液相密度方程得到的保形参数,由此推算其它区域内的Ｐ－Ｖ－Ｔ性质、第二ｖｉｒｉａｌ系数、焓、熵、热容和混合物的汽液平衡等热力学性质,计算结果与文献值符合较一致     

环氧树脂固化反应表观活化能的研究

用红外光谱法研究了Ｔ３１、低分子聚酰胺６５０（ＬＭＰ－６５０）固化环氧树脂反应的动力学参数。实验表明，环氧－Ｔ３１．固化反应的表观活化能为５４．５ＫＪ·ｍｏｌ~（－１），证明此反应常温下便有较高的速度；ＬＭＰ－６５０固化环氧反应的表观活化能为７４．４·４ＫＪ·ｍｏｌ~（－１），表明常温下反应较缓慢，固化程度随温度变化明显。红外光谱法不但可以定量研究环氧树脂固化反应动力学多数，而且可在催化剂选择、两组分配比等方面提供信息。     

应用重整化群理论计算超临界水的性质

采用重整化群理论计算了超临界水的性质.计算中考虑了密度涨落影响,水分子之间的势能采用Stockmayer函数.由临界温度回归得到的分子参数用来预测水在超临界和近临界区的热力学性质,并与实验结果进行比较.结果表明所采用的方法适合于预测水的超临界和近临界的热力学性质.     

1—2折流换热器流体温度沿程变化及其LMTD的计算

１－２折流换热器流体温度沿程变化及其ＬＭＴＤ的计算梁日忠ＴＨＥＶＡＲＩＡＴＩＯＮＯＦＦＬＵＩＤＴＥＭＰＥＲＡＴＵＲＥＡＬＯＮＧＳＩＤＰＡＳＳＡＮＤＴＨＥＣＡＬＵＡＴＩＯＮＯＦＬＭＴＤＩＮ１－２ＢＡＦＦＬＥＨＥＡＴＥＸＣＨＡＮＧＥＲ１前言换热器设计中，...     

极谱法测定冷却水中的乙二胺四甲叉膦酸钠

在６．８×１０＾－４ｍｏｌ．Ｌ柠檬酸钠，醋酸－醋酸钠缓冲溶液（ｐＨ＝５．２＋中，Ｃｕ＾２＋可与乙二胺四甲叉膦酸钠（ＥＤＴＭＰＳ）络合，使铜峰降低，峰电位Ｅｐ＝－０．２４Ｖ（银－氯化银电极）。乙二胺四甲叉膦酸钠浓度在３－５０ｍｇ／Ｌ范围内与峰高降低值呈线性关系。采用ＪＰ３－１型示波极谱仪，二次微分，起始电位０．００Ｖ，终止电位－１．２０Ｖ测定，检出银为１ｍｇ／Ｌ，变异系数为３．２％－６．０％，回收率     

酮麝香与二甲苯麝香体系相平衡研究

为了判断酮麝香、二甲苯麝香固相存在状态,改进Lennard-Jonnes位能函数后得到了适用于极性和非极性分子的位能函数式,计算得到酮麝香、二甲苯麝香体系相互作用能量参数λ,结合NRTL方程计算确认酮麝香、二甲苯麝香为简单低共熔体系,采用差分扫描量热热分析法进行了实验验证。     

不同位置取代的三氰基乙烯基蒽的光谱行为的研究

本文设计合成了两个典型的共轭的电子给体与电子受体化合物：２－三氰基乙烯基蒽与９－三氰基乙烯基蒽，通过极性效应，温度效应对它们基态与激发态的光谱行为进行了表征。研究表明：这两个化全物均表现出显著的电荷转移吸收峰，分子受光激发后，９－ＴＣＶＡ只能在非极性溶剂中产生分子内电荷转移态荧光，而２－ＴＣＶＡ在极性与非极性溶剂中都能从ＩＣＴ态发光。     

新的分子热力学模型及其应用(Ⅰ)——一种新的分子径向分布函数表达式的提出及其检验

根据液体的性质、实验现象及统计力学原理,根据总相关函数h(r)与阻尼振动之间存在的相似性,经过分析和数学处理得到了非电解质溶液径向分布函数表达式.应用该式于LJ流体、液态氩以及二元混合溶液体系,计算结果与文验、计算机模拟结果吻合较好.     

软球微扰状态方程的研究

从改进的势能函数出发,由径向分布函数理论和维里方程导出高温下纯流体配位数的计算公式,并与Sandler法结合求得简化的扰动型软球状态方程。用该方程计算的结果与Lennard-Jones模型的计算机模拟PVT数据吻合。     

Prediction of PVT behavior of polymer melts by the group-contribution lattice-fluid equation of state

The group-contribution lattice-fluid equation of state (GCLF-EOS), which is capable of predicting equilibrium behavior in polymer systems, was developed by establishing group contributions of the lattice-fluid EOS using the PVT properties of low molecular weight compounds only. This model was used to predict the PVT behavior of common polymers over a wide temperature range in the melt region and over a wide range of pressures up to about 2,000 bar. The GCLF-EOS predicted accurately the effect of pressure and temperature on the specific volumes of the polymer melts. Prediction results by the GCLF-EOS were compared with those by the group-contribution volume (GCVOL) method. The GCLF-EOS requires only the structure of the polymer repeat unit in terms of their functional groups as input information. No other polymer properties are needed. The GCLF-EOS is the only model that is capable of predicting the specific volumes of polymer melts as a function of temperature and pressure.     

TRANSPORT PROPERTIES OF DICHLORODIFLUOROMETHANE IN THE TEMPERATURE RANGE OF 280-450 K

Thermal conductivity of research grade pure dichlorodifluoromethane is measured in the temperature range 280-450?K employing the thermal conductivity column method. These data are compared with the most probable recommended values based on several data sets which scatter appreciably from each other. The molecular kinetic theory in conjunction with the Lennard-Jones (12-6) potential is employed to predict all the three transport properties of this gas. The inter-relations between the kinetic theory expressions for the viscosity and diffusion coefficients, which are essentially independent of the choice of intermolecular potential, are also used to predict these two properties.     

TRANSPORT PROPERTIES OF DICHLORODIFLUOROMETHANE IN THE TEMPERATURE RANGE OF 280-450 K

Thermal conductivity of research grade pure dichlorodifluoromethane is measured in the temperature range 280-450 K employing the thermal conductivity column method. These data are compared with the most probable recommended values based on several data sets which scatter appreciably from each other. The molecular kinetic theory in conjunction with the Lennard-Jones (12-6) potential is employed to predict all the three transport properties of this gas. The inter-relations between the kinetic theory expressions for the viscosity and diffusion coefficients, which are essentially independent of the choice of intermolecular potential, are also used to predict these two properties.     

六氟化硫PVT关系测定实验教学体会与思考

纯流体PVT关系测定及临界状态观察实验对于学生理解问题的本质,提高理论教学效果具有不可替代的作用。本文介绍了六氟化硫临界状态观察及PVT关系测定仪的制造及使用情况,重点介绍实验数据记录处理等细节上的一些经验体会和我们的建议。     

高压下长链分子的自扩散系数研究

在Lennard-Jones流体自扩散系数方程的基础上,结合链状硬球流体自扩散系数的分子模拟数据,提出了链状Lennard-Jones流体的自扩散系数方程。将所提出的方程应用于计算长链烷烃和硅油在0.1-600MPa下的自扩散系数,其平均相对偏差在10％以内,计算结果优于自扩散系数的粗糙Lennard-Jones模型。     

新的局部组成混合规则模型和汽液平衡数据的关联计算

从径向分布函数理论导出一个简单而合理的分子配位数计算公式,进而建立了新的局部组成模型,该模型简化后与改进的Peng-Robinson状态方程结合,在各类非理想体系汽液平衡计算中取得了满意的结果.     

用兰纳-琼斯位能和单参数Wilson方程预测汽液平衡

根据兰纳-琼斯位能提出计算Wilson方程中同类分子间能量参数g_(ⅱ)的一个简便方法,用于单能数Wilson方程可成功地预测二元体系汽液平衡,预测精度与已有方法相当,且仅需纯物质的基础物性数据T_c,P_c和Z_c。     

A semi-empirical molecular clustering based lattice model near to and far from the critical region

A semi-empirical molecular clustering based lattice fluid model is presented to improve the classical lattice model for volumetric properties in the critical region. This model is based on the two assumptions: (1) the Helmholtz energy is individually divided into classical and long-range density fluctuation contribution; (2) all molecules form cluster near the critical region due to long-range density fluctuation. To formulate such molecular clustering, we extended the Veytsman statistics originally developed for the cluster due to hydrogen bonding. The probability function in the statistics is modified to represent the characteristics of long-range density fluctuation vanishing far from critical region. The proposed fluctuation contribution was incorporated into the Sanchez–Lacombe model and the combined model with 6 adjustable parameters has been tested against experimental VLE data for polar and non-polar components. The combined model is found to good agreements with experimental vapor pressure, saturated density and supercritical PVT data.