相变

We also analyze the mechanism of the initial zinc blende structure and wurtzite structure phase transition in II-VI and III-V compound materials. The results indicate that the transition of zinc blende structure to rocksalt structure due to "chair" structure transform, the transition of wurtzite structure to rocksalt structure due to "chair" and "boat" structure transform.

对II-VI族和III-V族初始相为闪锌矿或纤锌矿的压致结构相变机制进行的分析表明，闪锌矿结构到岩盐矿的相变是因为"椅式"结构的变化，纤锌矿结构到岩盐矿的相变是因为"椅式"和"船形"两种结构的变化。

The type of magnetic phase transition in Dy(subscript 1-xGd Co2 compounds is found shifting from first order to second order as Dy is substituted by Gd, which is supposed to be the main reason for the detraction of MEC.

磁熵变下降的主要原因是Gd替代Dy后化合物的磁相变由一级相变转变为二级相变。

Shape memory alloy with thermoelastic martensite metallography transform represents absolute shape memory effect, for matrix metallography lattice orientation selectivity in reverse metallography transform.

具有热弹性马氏体相变的形状记忆合金，在逆相变中必定会选择相变前母相的晶格位向，表现出完全的形状记忆效应。

The formation of martensite is accomplished by the immigration of well-defined glissile interface (121)fcc type and its misfit dislocations can produce the lattice invariant deformation on the basis of phenomenal theory of martensitic crystallography, however, LID is retarded slightly after the migration of interphase (121)fcc, i.e.a thin plate-like zone exists without LID in martensite near the well-defined interface. When the temperature reduces to the Ms point, the lattice parameter of austenite matrix is √3/2 times that of the martensite without LID. This critical condition for spontaneous transformation agrees with that the stack fault energy in matrix is less than zero according to Olson and Cohen's nucleation model.

通过模型分析表明：fcc/bcc马氏体形核与长大过程是通过(121)fcc型择优界面推移进行的，界面上的错配位错可以完成马氏体晶体学唯象理论要求的点阵不变变形，但LID要稍滞后于界面迁移，即在马氏体形核与长大过程中推移界面新相一侧存在一未发生LID的新相薄区；当相变温度达到马氏体相变点Ms时，母相奥氏体与这一薄区的晶格常数比为√3/2，这一几何条件和Olson-Cohen形核模型中要求扩展位错层错区界面能γ≤0是等价的。

Keywords: Phase transformation; Impact; Phase transformation Taylor's Bar; Constitutive model; Phase boundary

中文关键词：相变冲击；相变Taylor杆；相变本构；相边界

From the theory of phase transformation and thermal elastoplastic, and based on experimental data of laser quenching, a non linear coupling heat conduction equation considering phase transformation, temperature field and variable physical properties can be estabilished.

从相变理论和热弹塑性理论出发，并结合激光淬火实验资料，建立了考虑相变过程、温度场和变物性系数的非线性耦合热传导方程；建立了相变组织与材料性能的数值计算模型。

The results indicated that there were two-phase and three-phase regions only,was not any trinal intermediate phase in the investigated Si content range.Two binary pseudo-alloys took place solid-phase changes at 556℃ and 471℃ respectively.

结果表明：在研究的Si含量范围内，相组成较复杂，但仅有二相区和三相区，未发现三元中间相。2个伪二元合金系在556℃和471℃存在固相转变，且Cu3Si相的η、η′和η"相同属正交晶系，其相变属于"位移型相变，空间群有待进一步研究。

By investigating a series of homologous cholesteric liquid crystal materials,it is found that the cholesteric liquid crystal phase transition temperatures reduce along with change length of the molecules.

首次报告利用液晶分子的机械旋转模型研究胆甾相液晶材料相变与分子构造相关性的研究结果。通过对不同质量的系列胆甾相液晶材料的研究，发现材料的相变温度随着分子的变长而降低。

The phenomenon demonstrates that the perovskite is a stable state with low free energy. The (1-x) PMN- x PT system has a morphotropic phase boundary separating the tetragonal and rhombohedral phases. The MPB is located in the vicinity of x = 33%. The PMN-PT ceramics near the phase boundary possesses excellent piezoelectric performance. d33 can reach to 540 pC/N. kt and kp can be up to 0.45 and 0.62, respectively.

在准同型相界附近，PMN-PT陶瓷材料具有较好的压电性能，d33可达540 pC/N，kt、kp分别可达0.45和0.62；在准同型相界附近，极化后的（1-x）PMN-xPT陶瓷材料（0.22 x 0.35）的介电常数在温度诱导FR-FT相变过程中发生突变；PMN-PT陶瓷材料在FR-FT相变过程中呈现出一个热释电峰，反应了自发极化在相变过程中发生了非线性的变化。

Combining the mechanism of oxygen diffusion with the block model in YBCO, the mechanism of the phase transitions can he explained as follows: the phase transition at 400℃ comes directly from O(1) in the rock salt block, and corresponds to the beginning of O-T; the phase transition at 850℃ corresponds to the end of O-T, when O(2) and O(3) of Cu(2)-O plain are rearranged and a few oxygen enter O(1) site of Cu(1)-O plain through O(4) bridge atom, and at last escape from the crystal cell. Thus the phase transition at 850℃ is related with the pervoskite block.

结合YBCO中氧扩散机制和块模型，相变机理解释如下：400℃的相变直接来自于岩盐块，对应于正交－四方转变的起点；850℃相变对应于正交－四方转变的终点，此时Cu(2)-O面中的O(2)和O(3)重排，一些O通过O(4)桥原子进入O(1)位，最后逸出晶胞，因而850℃相变与钙钛矿关系密切。

It has been put forward that there exists single Ball point and double Ball points on the symmetrical connecting-rod curves of equilateral mechanisms.

从鲍尔点的形成原理出发，分析对称连杆曲线上鲍尔点的产生条件，提出等边机构的对称连杆曲线上有单鲍尔点和双鲍尔点。

The factory affiliated to the Group primarily manufactures multiple-purpose pincers, baking kits, knives, scissors, kitchenware, gardening tools and beauty care kits as well as other hardware tools, the annual production value of which reaches US$ 30 million dollars.

集团所属工厂主要生产多用钳、烤具、刀具、剪刀、厨具、花园工具、美容套等五金产品，年生产总值3000万美元，产品价廉物美、选料上乘、质量保证，深受国内外客户的青睐