一组适合炼厂水蒸汽参数的快速计算方程

本文以IAPWS-IF97为基础,参考有关文献,提出一组水和水蒸汽热力性质计算的简明方程,包括饱和蒸汽压、饱和液密度、饱和汽密度、饱和液焓、饱和汽焓、汽化潜热6个方程,并以IAPW S-IF97的计算结果拟合了方程中的常数。所提出的6个方程,形式简单,使用方便,具有良好的计算精度,完全覆盖石化、炼油企业所用蒸汽参数范围。     

Molecular dynamics studies of two hard-disk particles in a rectangular box I. Thermodynamic properties and position autocorrelation functions

Molecular dynamics simulations have been carried out for the simple few-body systems of two hard-disk particles confined within a 2-dimensional rectangular box. Wall pressures, the collision frequencies, density profiles, two-particle probability distributions, and position autocorrelation functions were computed to examine the thermodynamic, structural and time-dependent properties of such systems. Excellent agreement was found between simulation results and theoretical predictions recently proposed by Munakata and Hu. Detailed dynamic effects are also discussed to describe configurational particle trajectories including fast/slow relaxation processes observed in the position autocorrelation functions. Professor Hyun-Ku Rhee on the occasion of his retirement from Seoul National University     

Thermodynamic modeling of vapor-liquid equilibria and excess properties of the binary systems containing diethers and n-alkanes by cubic equation of state

A comparison of the performances of two different approaches of cubic equations of state models, based on a classical van der Waals and mixing rules incorporating theG ^E equation, was carried out for correlation of Vapor-Liquid Equilibria (VLE), H^E and C _P ^E data alone, and simultaneous correlation of VLE+H^E, VLE+C _P ^E , H^E +C _P ^E and VLE+H^E +C _P ^E data for the diethers (1,4-dioxane or 1,3-dioxolane) with n-alkane systems. For all calculations the Peng-Robinson-Stryjek-Vera cubic equation of state (PRSV CEOS) was used. A family of mixing rules for the PRSV CEOS based on the Modified van der Waals one-fluid mixing rule (MvdW1) and two well-known CEOS/G^E mixing rules (MHV1 and MHV2), was considered. The NRTL equation, as the G^E model with linear or reciprocal temperature dependent parameters, was incorporated in the CEOS/G^E models. The results obtained by the CEOS/G^E models exhibit significant improvement in comparison to the MvdW1 models.     

Formation mechanism of β-Sialon with different morphologies based on DFT calculation and its effect on the performance of refractory composites

β-Sialon with whisker-like, columnar, and plate-shaped structures was successfully synthesized with Al₂O₃–C refractory compositions. In the presence of a catalyst, the preferential growth face of columnar β-Sialon was (100), whereas plate-like β-Sialon preferred (101) and (111). DFT calculations demonstrated that the SiO adsorption energy on the (100), (101), and (111) faces of β-Sialon crystal were –34.95, –52.88, and –45.08 eV, respectively. Therefore, the (101) and (111) faces were more stable in Al-rich β-Sialon. With the increase in catalyst content, the Si-rich Si–Al–O–N liquid phases, which contributed to the generation of columnar β-Sialon, were converted into the Al-rich Al–Si–O–N system that was conducive to the formation of plate-like β-Sialon. Compared to the sample without the catalyst, the CMOR and HMOR of the specimen were increased by 45.07% and 60.47%, respectively, with the addition of Fe₂O₃. This was attributed to the formation of β-Sialon with a one- or two- dimensional shape.     

硅酮粉对改性PC体系的耐划伤性能的研究

主要用硅酮粉对已用质量分数为5%的晶须硅改性后的聚碳酸酯(PC)体系进行了抗划伤改性;测定了改性后PC体系的热力学、力学、流变和耐划伤性能。通过比较和分析试验数据,得出了硅酮粉对PC+5%晶须硅体系耐划伤改性的最佳配方即PC+5%晶须硅+1%硅酮粉。     

Excess molar volumes and molar enthalpies in the binary mixtures of {x1CH3CHClCH2Cl+x2CH3(CH2)n?1OH} (n=1 to 4) at T=298.15K

The excess molar volumes V _m ^E and excess molar enthalpies H _m ^E at T=298.15 K and atmospheric pressure for the binary systems {x₁CH₃CHClCH₂Cl+x₂CH₃(CH₂) _n−1OH} (n=1 to 4) have been determined from density measurements by using a digital vibrating-tube densimeter and an isothermal calorimeter with flow-mixing cell, respectively. The 1-alkanols are methanol, ethanol, 1-propanol and 1-butanol. The V _m ^E values of the binary mixtures increase with chain length of the 1-alkanols, resulting in entire negative V _m ^E values for methanol, ‘S-shaped’ for ethanol, being nega- tive at low and positive at high mole fraction of 1,2-dichloropropane, and entire positive V _m ^E values for both 1-propanol and 1- butanol. The H _m ^E values for all systems show an endothermic effect (positive values), which exhibits a regular increase in magnitude when the number of -CH₂- group in 1-alkanols is progressively increased and maximum values of H _m ^E varying from 741 J·mol⁻¹ (methanol) to 1,249 J·mol⁻¹ (1-butanol) around x₁=0.63−0.72. The experimental results of both H _m ^E and V _m ^E were fitted to Redlich-Kister equation to correlate the composition dependence. The experimental H _m ^E data were also used to test the suitability of the Wilson, NRTL, and UNIQUAC models. The correlation of excess enthalpy data in these binary systems using UNIQUAC model provides the most appropriate results except for the system containing methanol.     

On the information and methods for computing phase equilibria and thermodynamic properties

The Helmholtz free energy or an equation of state relating temperature, pressure, volume and composition plays a key role in the calculation of phase equilibria and thermodynamic properties. Such information is usually available for vapor, partially available for liquids, and rarely available for solids. Depending on the information available, different methods are used for properties calculation. In this study, various methods were systematically presented and their relations with available information were comprehensively discussed.     

碳氢燃料与空气混合物爆轰性能实验研究

利用矩形激波管测定了几种碳氢燃料与空气混合物的爆轰极限和临界起爆能。根据分子结构的不同，对实验结果进行了分析。     

炸药爆轰波光谱发射率及爆温的虚拟辅助光源反射法测量

依据光学原理,提出了爆轰波光谱发射率及爆温的虚拟辅助光源反射测量方法,克服了单波长或双波长光学测试装置不能同时测量两参量的困难,利用该方法对液体炸药ＮＭ爆轰波光谱发射率及其爆温进行了实验测量,结果与文献报道相吻合。