二维DNA晶体的多重熔解过程研究

可人工编程设计的刚性DNA分子瓦(DNA tile)中的DX分子(double-crossover，双交叉)能自组装形成二维DNA晶体。将含有二维DNA晶体的缓冲溶液程序升温，用紫外-可见分光光度计在260 nm处测定二维DNA晶体的熔解曲线，观测到了DNA晶体的多重熔解过程。AFM显微镜的研究也观测到了二维DNA晶体受热解体后的图像，表明二维DNA晶体的熔解过程首先发生在DX分子瓦间的黏性末端，然后是DX分子瓦的解体，由此推测，在DNA晶体生长过程中单链DNA相互结合成分子瓦后，分子瓦进一步自组装成晶体。     

THERMOTROPIC LIQUID CRYSTALLINE COPOLYESTERS-SOLID STATE POLYMORPHISM

This paper offers some new evidence on the polymorphism of solid state of liquid crystalline aromatic copolyesters which were prepared in our laboratory. The effects of different treatment conditions(quenching and annealing) on solid structure have been examined mainly by DSC and X-ray diffraction. The discussion focuses on the supercooled mesophase and low temperature solid-solid transition, the shifting of double melting peaks of annealed samples and the changing of their ΔH data depending on the treatment temperature, time and thermal scanning rate.     

原位X射线研究拉伸过程中间规聚丙烯晶体熔融与晶体取向关系

间规聚丙烯熔体(sPP)淬冷至液氮温度并保持5 min, 于20, 40, 80, 120 ℃下等温退火10 h, 制备出具有不同片晶厚度的样品. 在室温条件下, 利用原位X射线在线研究sPP样品拉伸过程中应力诱导的晶体熔融和晶体取向关系. 结果表明, 在单轴拉伸过程中, 应力导致的晶体熔融和晶体取向同时发生, 即两者在同一应变、 同一应力下同时发生, 这一特性不受片晶厚度的影响. 随着片晶厚度的增加, 晶体熔融和取向需要的临界应力不断增大, 在所研究范围内, 该临界应力的增加和片晶厚度基本呈线性关系. 另外, 随着片晶厚度增大, 样品的弹性模量、 屈服强度和应变硬化模量均有一定程度的增大.     

YJ-3000t型紧装式六面顶大腔体高温高压实验装置样品室的压力标定

 在温度为389~1 245 ℃和砧面压力为1.0~5.0 GPa的条件下,利用金属高压熔融标定法,采用Cu、Al、Zn和Pb四种金属,对YJ-3000t型紧装式六面顶大腔体高温高压实验装置样品室内的实际压力进行了标定。通过对由四种金属所获得的标定结果的多项式三维模拟,获得了以叶蜡石为外传压介质、氧化铝为内传压介质的情况下,由砧面压力和样品室温度估算样品室内实际压力的定量表达式。该结果可为今后该设备上类似实验组装中样品腔内实际压力的估算提供方便准确的压力标。     

New Voronoi Diagram Algorithm of Multiply-Connected Planar Areas in the Selective Laser Melting

This paper studies the practical generation of Voronoi diagrams for multiply-connected planar areas bounded by line segments. The core of the algorithm was calculating Voronoi polygon of every Voronoi object in planar areas independently. The main approach had two steps. The first step was calculating all relevant bisectors of every Voronoi object. The second was combining obtained bisectors into completed Voronoi polygons individually. All code was implemented in Visual C++ platform. The resulting code was extensively tested in real-world data and its practical running time grew only linearly. Three statistical CPU-consumption charts had been drawn with the Voronoi diagrams computation data, and compared with other published codes for computing Voronoi diagrams. The algorithm was applied to compute offsetting of slice area consisting of large-scale line segments for the selective laser melting (SLM) trajectory scanning technology which is a kind of rapid prototyping (RP). The experimental results of offsetting for slice area based on Voronoi diagrams show that the approach is effective and simple for polygon offsetting problems. The method is helpful to those offsetting work and can provide more effective offsetting solution.     

A model of melting of rare gases within bubbles of crystalline metal matrix

Abstract

On the basis of experimental results obtained in the present and some other works a model of melting of rare gas solids within bubbles formed in a crystalline metal matrix as a result of ion implantation is proposed. Rare gas solid is supposed to melt on heating at the expense of the bubble volume expansion by emission of a dislocation loop. On this basis the melting temperature can be estimated as one which is enough to provide for a pressure inside a bubble sufficient for the initiation of the dislocation loop punching. Values of melting temperatures obtained in this way are in good agreement with available experimental data.     

Thermal Conductivity of CuSbSe2 and CuBiSe2 in the Solid and Liquid State

Abstract

Thermal Conductivity of CuSbSe₂ and CuBiSe₂ have been studied in the solid and liquid state in a wide range of temperatures. Measurements of thermal conductivity were carried out using the concentric cylinder method which is based on the flow of heat through a cylindrical wall.     

浙东南沿海地区中生代火山岩—侵入杂岩形成条件的实验模拟

本文研究了浙东南沿海地区中生代火山—侵入杂岩的熔融温度,老浆粘度及其与岩石成分之间的关系,讨论了它们的岩石学意义。     

多元金属共渗高炉风口的传热分析

分析了水冷高炉风口的传热过程，对多元金属共渗高炉风口的导热热流密度进行了计算。计算结果表明，这种风口的导热能力仅提高３％。因此，这种风口只能在很有限的程序上提高其抗热流冲击的能力。