在高压下双原子分子的行为

位于美国华盛顿洲的Carnegie研究所的A．Goncharov教授的他的合作者美国Lawrence Livermore国家实验室的J．Crowhurst教授共同进行了一项实验．他们将许多种类的双原子分子，例如氢、氘和氮等挤压人一个菱形的砧格内，然后观察它们在高温高压下的行为．在实验中他们不断地改变温度与压强这两个参数，使分子样品常常可以从流体转变为晶体，或者反过来从晶体变为流体，甚至于让整个分子解体．他们的具体实验手段是利用近红外激光对样品加热，再利用拉曼光谱仪来测定分子在各种条件下的量子振动激发态，并细缄地记录下各条谱线的频率与伸缩模的线宽。     

铝板带冷轧过程中磨损影响因素 及磨损作用机制研究

轧后铝材表面磨损量是影响铝材轧制过程的重要因素,脱落的铝粉恶化产品表面质量、影响轧制效率。本文选用不同的添加剂配制轧制油,对铝板材进行冷轧试验,重点研究添加剂种类、铝材原始表面质量、轧制压下率三方面对铝材表面磨损性能及磨损机制的影响。结果表明：双组分添加剂轧制油中油性剂在金属表面吸附成膜,犁削磨损现象较无润滑和纯基础油轧制有明显改善,轧后铝材表面磨损量小;轧件轧前表面粗糙度大,轧辊对轧件微凸体的碾压作用加剧,被碾压下来的大量铝粉成为轧辊和轧件外的“第三体”,造成磨粒磨损加剧;化学磨损和犁削磨损同时存在于轧制过程中,油膜厚度较大时,前者是主要磨损机制;反之,后者起主导作用。     

高温高压的流动溶液内矿物-水反应动力学研究

本文着重介绍高温高压下开放流动体系内矿物-水反应动力学的最新研究成果。在研究了连续流动体系中方解石-水的反应速度方程后又在稳态操作的化学动力学实验中发现了偶存于其中的非稳态动力学过程。同时用轴向弥散模型和叠层反应器研究了萤石和钠长石反应动力学机理。本文还研究了不同温压、流速、介质和不同的溶液性质对反应速度的影响及控制因素。     

First-Principles Study of Structural Stabilities, Electronic and Optical Properties of SrF2 under High Pressure

An investigation of structural stabilities, electronic and optical properties of SrF2 under high pressure is conducted using a first-principles calculation based on density functional theory （DFT） with the plane wave basis set as implemented in the CASTEP code. Our results predict that the second high-pressure phase of SrF2 is of a Ni2In- type structure, and demonstrate that the sequence of the pressure-induced phase transition of SrF2 is the fluorite structure （Fm3m） to the PbC12-type structure （Pnma）, and to the Ni2In-type phase （P63/mmc）. The first and second phase transition pressures are 5. 77 and 45.58 GPa, respectively. The energy gap increases initially with pressure in the Fm3m, and begins to decrease in the Pnma phases at 30 GPa. The band gap overlap metallization does not occur up to 210 GPa. The pressure effect on the optical properties is discussed.     

Reshock Response of 2A12 Aluminum Alloy at High Pressures

By means of mounting the specimen on a low-impedance buffer, reshock experiments were carried out on a 2A12 almninum alloy up to shock stresses＇ of 67.6 GPa. Reshock wave profiles from the initial shock stresses of 60.9-67.6 GPa were measured with a velocity interferometer, and it shows that the 2A12 aluminum alloy characterizes as quasi-elastic response during recompression process. The Lagrange longitudinal velocities along the reloading path from initial shock state were obtained from two shots of experiments, while the bulk velocities at corresponding shock stresses were determined via extrapolating from the public reported unloading plastic sound velocities. Combining the reshock and the release experimental results, the yield strength of 2A12 aluminum alloy at shock stress of 60.9 GPa was estimated to be about 1.7GPa.     

The Phase Transition of Eu2O3 under High Pressures

Pressure-induced phase transition of cubic Eu2 03 is studied by angle-dispersive x-ray diffraction （ADXD） up to 42.3 GPa at room temperature. A structural transformation from a cubic phase to a hexagonal phase is observed, which starts at 5.0 GPa and finishes at about 13.1 GPa. The phase transition leads to a volume collapse of 9.0% at 8.6 GPa. The hexagonal phase of Eu2 03 maintains stable up to the highest experiment pressure. After re/ease of pressure, the high-pressure phase transforms to a monoclinic phase. The pressure-volume data are fitted with the Birch-Murnaghan equation of state. The bulk moduli obtained upon compression from the fitting are 145（2） GPa and 151（6） OPa for the cubic and hexagonal phases, respectively, when their first pressure derivatives are fixed at 4.     

固态氧在高压下失去磁性

通常水波只在浅水中被折射，香港科技大学的科学家发现，一批周期性排列的固定在海底并竖直延伸到水面的圆柱体改变了水的“有效”深度和引力常数，这导致水波被折射。他们指出，有效引力常数可由通常的9．8m／s^2增加到16m／s^2．     

高温高压下NaCl热力学特性的分子动力学模拟

欲了解固体物理和地球内部特征就要弄清固体在高温高压的热力学特性，而碱金属卤化物的研究有利于在实验室难以接近的高温高压条件下建立金属氧化物的相转变模型。文中应用分子动力学方法模拟NaCl离子晶体的高压熔化、高温高压下热力学参数，如热容、等压体膨胀系数、等温体模量、Gruneisen参数等。     

Synthesis of 1,1′-binaphthyl-2,2′-diamine from 2-naphthol under atmospheric pressure

A practical protocol to obtain 1,1'-binaphthyl-2,2'-diamine was developed from 2-naphthol and 2-naphthylhydrazine under mild conditions:solvent-free,125-130℃,atmospheric pressure.The convenient procedure makes the process amenable for large-scale synthesis of the versatile compound.     

化学反应ΔrGm的物理意义

△rGm是物理化学中常用的重要物理量,在相应的教材中都有一定的介绍.本文从范霍夫反应等温式出发,经简单的处理,清晰地揭示了△rGm的涵义在有限体系内化学反应的△rGm是由两种因素贡献的,即等温等压下发生的纯化学反应的△rGm*及等温等压下产物与反应物的混合引起的△mixG相迭加的结果,且后者是随反应时间不断改变的.