Controlling synthesis of BiIn dendritic nanocrystals by solution dispersion

In this study, we report a novel and simple solution-phase route for one-dimensional metal nanocrystals. BiIn nanocrystals were prepared by directly dispersing melting BiIn alloy at an appropriate solvent. The as-obtained BiIn nanocrystals with a dendritic shape possess a good crystalline phase. The morphology of the nanocrystals can be greatly modified by changing the reaction parameters. This strong UV emission might arise from the quantum-confined In2O3 particles.     

Neural Network Models for Finline Discontinuities

The radial basis network is used as the finline discontinuities electromagnetic artifical neural network(EMANN) models. EM software analysis is employed to characterize finline discontinuities. EMANN models are then trained using physical parameters and frequency as inputs and equivalent electric circuit element parameters of finline discontinuities as outputs. Once trained , the EMANN models can simulate equivalent electric circuit element parameters of finline step, notch and strip very fast and efficiently.     

Self-organized periodic photonic structure in a nonchiral liquid crystal

A hybrid-aligned cell of the smectic A liquid material 8CB gives two stable director configurations, one of which is periodic and gives strong diffraction of light. This photonic lattice director profile arises from "frustration" caused by conflicting constraints imposed by the boundary conditions and the constant amplitude smectic density wave. A model is proposed which accords well with the experiment results, predicting correctly the dependence of the periodicity on the cell thickness and reproducing optical polarization microscopy results.     

深过冷Ag-Cu-Ge三元共晶合金的相组成与凝固特征

在Ag_38.5Cu_33.4Ge_28.1三元共晶合金的深过冷实验中，获得的最大过冷度为175 K(0.22T_E). XRD分析表明，不同过冷条件下其共晶组织均由(Ag),(Ge)和η(Cu₃Ge)三相组成. 在小过冷条件下，三个共晶相协同生长，凝固组织粗大.随着过冷度的增大，共晶组织明显细化，(Ge)相与其他两相分离，以初生相方式生长，而(Ag)相与η相始终呈二相层片共晶方式共生生长. 当过冷度超过80 K时，初生相(Ge)由小过冷时的块状转变为具有小面相特征的枝晶方式生长. 部分小面相(Ge)枝晶出现规则的花状，花瓣数介于5—8之间，并且过冷度越大(Ge)相越容易分瓣. 花状(Ge)枝晶的晶体表面为{111}晶面簇，择优生长方向为〈100〉晶向族. 关键词： 三元共晶 晶体形核 深过冷 快速凝固     

Dendritic and eutectic growth in Sb<Subscript>60</Subscript>Ag<Subscript>20</Subscript>Cu<Subscript>20</Subscript> ternary alloy

The rapid solidification of Sb60Ag20Cu20 ternary alloy was realized by high undercooling method, and the maximum undercooling is up to 142 K (0.18TL). Within the wide undercooling range of 40-142 K, the solidified microstructures are composed of (Sb), θand ε phases. High undercooling enlarges the solute solubility of (Sb) phase, which causes its crystal lattice to expand and its crystal lattice constants to increase. Primary (Sb) phase grows in two modes at small undercoolings non-faceted dendrite growth is the main growth form; whereas at large undercoolings faceted dendrite growth takes the dominant place. The remarkable difference of crystal structures between (Sb) and θphases leads to (θ Sb) pseudobinary eutectic hard to form, whereas strips of θform when the alloy melt reaches the (θ Sb) pseudobinary eutectic line. The cooperative growth of θand ε phases contributes to the formation of (ε θ) pseudobinary eutectic easily. In addition, the crystallization route has been determined via microstructural characteristic analysis and DSC experiment.     

无回路规则系统的Petri网验证方法

构建了无回路规则系统的加标ω-Petri网模型，产生了相应的可达树，利用可达状态反映规则系统所包含的所有可达关系，并记录；提出了可达状态的反向推演森林及其算法，实现规则系统命题间可达路径的显式化．在此基础上，给出了规则系统错误的判定定理及其检测算法，实现了结构错误的有效判定和分析．     

Formation of ζ phase in Cu-Ge peritectic alloys

Rapid growth behavior of ζ phase has been investigated in the undercooling experiments of Cu-14%Ge, Cu-15%Ge, Cu-18.5%Ge and Cu-22%Ge alloys. Alloys of the four compositions obtain the maximum undercoolings of 202 K（0.17TL）, 245 K（0.20TL）, 223 K（0.20TL） and 176 K（0.17TL）, respectively. As the content of Ge increases, the microstructural transition of ＂a（Cu） dendrite ＋ ζ＂ peritectic phase → ζ＂ peritectic phase →, ζ dendrite ＋ （ε＋ζ） eutectic＂ takes place in the alloy at small undercooling, while the microstructural transition of ＂fragmented α （Cu）dendrite ＋ ζ peritectic phase →, ζ peritectic phase →ζ dendrite ＋ ε phase＂ happens in the alloy at large undercooling. EDS analysis of the Ge content in peritectic phase indicates that undercooling enlarges the solid solubility of ζ rdendrite, which leads to a decrease in the Ge content in ζ phase as undercooling increases. In the Cu-18.5%Ge alloy composed of ζ peritectic phase, the Ge content in ζ phase increases when undercooling increases, which is due to the restraint of the Ge enrichment on the grain boundaries by high undercooling effect.     

西秦岭厂坝-李家沟铅锌矿矿床地质特征和成因分析

摘要：厂坝一李家沟矿床规模巨大，是秦岭地区西成铅锌成矿带的重要矿床之一。矿体形态和规模明显受沉积洼地控制。矿石常显微莓球状、针状、他形隐晶质、显微球粒结构。可识别的矿石沉积一成矿作用构造有浸染一条带状、条纹一条带状、隐晶质条带、条块状、块状构造等。矿体中下部主要为块状矿石，富黄铁矿、闪锌矿、钠长石和石英；上部为条带状、浸染状和层纹状矿石，富闪锌矿、重晶石和方解石。条带状的石英钠长石岩和重晶石所含的典型喷气元素B和As的含量比正常沉积岩高出几倍到几十倍。闪锌矿中Zn／Cd〉〉500，黄铁矿中Co／Ni为O．2～O．8。另外，该矿主要形成于受裂谷控制的克拉通内部及其边缘的沉降盆地。结果表明，厂坝矿具有较典型的Sedex型矿床特征。[第一段]