Melting and Grüneisen parameters of NaCl at high pressure

The Buckingham potential has been employed to simulate the melting and thermodynamic parameters of sodium chloride (NaCl) using the molecular dynamics (MD) method. The constant-volume heat capacity and Grüneisen parameters have been obtained in a wide range of temperatures. The calculated thermodynamic parameters are found to be in good agreement with the available experimental data. The NaCl melting simulations appear to validate the interpretation of superheating of the solid in the one-phase MD simulations. The melting curve of NaCl is compared with the experiments and other calculations at pressure 0－30GPa range.     

含受弯根键的根式沉井承载性能分析

根据荷载传递法及Winkler地基梁理论,考虑根键弯曲及重叠折减效应,推导了含受弯根键的根式沉井承载性能的弹性解答,计算值在弹性范围内与实测值接近.给出了竖向位移和轴力随深度的分布曲线,并分析了根键的受力性状以及各部分土反力的分担比例等.结果表明,根式沉井的承载性能明显优于传统沉井基础,可应用于工程建设中,但根键的弯曲效应会降低基础的承载性能,故在设计中应提高根键的抗弯刚度.     

内燃机缸套-活塞环磨合过程中微凸体承载研究

为获得内燃机缸套-活塞环磨合磨损过程中微凸体的承载情况,利用粗糙峰的接触模型推导出磨合过程中微凸体承载方程,其中对弹性变形部分微凸体承载和塑性变形部分微凸体承载分别进行了研究,重点比较了内燃机缸套-活塞环磨合过程中假定接触微凸体全部为弹性变形与考虑接触微凸体产生弹?塑性变形时承载能力的不同.研究结果表明,在磨合磨损的中后期,即当h/σ大于0.5,ψ小于0.9时,两者差别不大,可以假定微凸体变形全部为弹性变形进行微凸体载荷的计算;而在磨合磨损初期,即当h/σ小于0.5,ψ大于0.9时,假定微凸体变形全部为弹性变形时的承载为考虑弹?塑性变形时的50%~85%左右.考虑到内燃机缸套-活塞环磨合过程中初期磨合的重要性,在计算缸套-活塞环磨合过程中微凸体承载时,应将塑性变形部分微凸体和弹性变形部分微凸体承载分别进行研究.也说明了本文所建立的微凸体承载方程更有益于缸套-活塞环磨合过程的摩擦学状态分析.     

软土地区桩端后注浆桩承载性状对比试验研究

桩端后注浆技术是在通过预埋的压浆管对桩底压注水泥浆液,从而减少桩底沉渣和桩周泥皮的负面影响,在工程上逐渐得到广泛应用。结合宁波软土地基中某工程桩基静载荷试验,分析2根相邻后注浆和未注浆试桩的承载性状;通过对桩身预埋钢筋应力计的测试,对后注浆和未注浆桩的桩身轴力传递特性和桩侧阻力发挥特性进行比较分析研究。表明桩端后注浆不仅能提高端阻,还能提高桩端以上一定范围内土层的侧摩阻力,同时,后注浆桩的单桩极限承载力约为未注浆桩的2.5倍。根据以上研究结果表明,桩端后注浆技术能有效改善桩土界面条件,提高单桩承载力和减小桩基沉降。     

离子型化合物与氧化物载体表面相互作用的研究—“嵌入模型”及其应用

离子化合物与氧化物载体间相互作用的研究是从本质上探索负载型催化剂的物理化学性质的有效途径。在考虑载体的表面结构和离子化合物的本征性质 (价型、离子半径和电子构型等 )的基础上 ,用“嵌入模型”说明或预测一些离子化合物在不同的氧化物载体上的分散容量 ,为催化剂的设计和制备提供科学依据。本文就课题组近十年来在这方面的工作作一简要介绍     

硫酸氢钾(KHSO4,A.R.)的低温热容和热化学性质

硫酸氢钾（ＫＨＳＯ4,Ａ．Ｒ）是一种重要的无机化工原料。在化肥工业中,它是生产复合肥硫酸铵钾（ＫＮＨ４ＳＯ４）的主要原料之一。为了找到工业上生产复合肥硫酸铵钾的最佳工艺条件,提高其产率和经济效益,并且开发其新的应用领域,迫切需要该化合物准确的热力学数据作为理论分析的依据。 硫酸氢钾的导热系数,溶解度,熔点等部分热物性数据［１－３］已有报道,但是,迄今为止,文献中未见到它的低温热容和热分解过程的详细报道。本文用精密自动绝热热量计直接测定了硫酸氢钾在７８－３７３Ｋ温区的热容,并且将实验热容值用最小二乘…     

A Zoom-In Approach to Design SDH Mesh Restorable Networks

Mesh restorable networks based on SONET (Synchronous Optical Network, standard optical transmission technology widely accepted and implemented in North America) or SDH (Synchronous Digital Hierarchy, the European standard currently adopted by the major European telecom operators) are an economically attractive solution in areas where high demand and high connectivity are involved (Wu, 1995). In these networks, the reconfiguration capability of the digital cross connect systems (DCS) allows to reroute the demand affected by network failures. The degree of sharing of spare capacity in networks based on this architecture is high.This paper presents a heuristic algorithm for solving the near-optimal design of SDH mesh-type link restorable networks, i.e. determining the network topology and assigning the capacity to transport the demand in normal situations and to allow full link restorability in case of single link failures. The algorithm is based on a Zoom-In technique, a novel approach which forms a compromise between sequential and integrated techniques. The different building blocks of the algorithm are tested extensively and compared with other results mentioned in literature. Comparison of the simulation results for the overall design problem with other solution techniques indicates that the Zoom-In method is a quite promising approach, able to combine the accuracy of integrated approaches with the calculation speed of sequential approaches.     

Efficacy of Polyaniline (PANI) nanofibres for capturing Diclofenac (DC) drug from its aqueous solutions

Pharmaceutical drug contamination in water nowadays is deteriorating the ecological components. A remedial approach is therefore a necessity. This study focuses on the synthesis of PANI nanofibres employing the oxidative polymerization method using ammonium persulphate (APS) as oxidant. The synthesized nanofibres were characterized using HR-TEM, FT-IR and XRD. The HRTEM image exhibited the nano-range structure of PANI with a rough surface. The FT-IR spectra inferred about the role of surface capping groups involved in the uptake mechanism. The crystallinity of PANI was well assessed by the X-Ray Diffraction analysis. The interaction between the studied drug diclofenac (DC) and polyaniline (PANI) showed a rapid equilibrium time 120 min favored at pH 5.0 achieving maximum adsorptive capacity (q_e) of 471.08 mg g ^?1. The uptake process followed the pseudo-second order kinetic model (R² = 1) with intra-particle diffusivity model (R² = 0.9810) as the governing step and best fitting values into Langmuir isotherm model (R² = 0.9822) inferred about the favourable adsorption of DC forming monolayer over PANI having q_m to be 943.83 mg g^?1. The drug DC was easily desorbed up to 85.31% by using 0.1 M aq ethanol and was exhausted after five cycles of reusability. The whole adsorptive mechanism involved electrostatic interactions along with hydrogen bonding.