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INTERACTION OF A DISLOCATION DIPOLE WITH A MODE III INTERFACE CRACK

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Acta Mechanica Solida Sinica 2007年第1期20卷 50-56页

作者： Jin Bo fang Qihong liu Youwen College of Civil Engineering Hunan University Changsha 410082 China College of Mechanics and Aerospace Hunan University Changsha 410082 China

Interaction between a screw dislocation dipole and a mode III interface crack is investigated. By using the complex variable method, the closed form solutions for complex potentials are obtained when a screw dislocation dipole lies inside a medium. The stress fields and the stress intensity factors at the tip of the interface crack produced by the screw dislocation dipole are given. The influence of the orientation, the dipole arm and the location of the screw dislocation dipole as well as the material mismatch on the stress intensity factors is discussed. The image force and the image torque acting on the screw dislocation dipole center are also calculated. The mechanical equilibrium position of the screw dislocation dipole is examined for various material property combinations and crack geometries. The results indicate that the shielding or anti-shielding effect on the stress intensity factor increases abruptly when the dislocation dipole approaches the tip of the crack. Additionally, the disturbation of the interface crack on the motion of the dislocation dipole is also significant.

关键词： dislocation dipole interface crack image force image torque

Temporal distribution of piperocks in Cambrian and Ordovician: A coevolutionary process with changes of paleoenvironment

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Science China Earth Sciences 2012年第1期55卷 26-38页

作者： fang Liang liu JianBo ZHAN RenBin School of Earth and Space Sciences Peking UniversityBeijing 100871China Key Laboratory of Orogenic Belts and Crustal Evolution(Peking University) Ministry of EducationBeijing 100871China State Key Laboratory of Palaeobiology and Stratigraphy Nanjing Institute of Geology and PalaeontologyChinese Academy of SciencesNanjing 210008China

Piperock, a kind of characteristic ichnofabrics in Phanerozoic, was thought to decline gradually from Cambrian to Ordovician. A new compilation on the occurrences of the Cambrian and Ordovician piperocks of China and the world shows that piperocks generally flourished in Cambrian and declined in Ordovician, but a sharp decrease occurred during Middle and Late Cambrian. The case-study on the piperocks from the Lower-Middle Ordovician Hongshiya Formation at Dabaochang of Qiaojia, northern Yunnan Province, Southwest China indicates that the forming and preservation of piperocks were controlled by the depositional environment, the intensities of predation, competition, bioturbation, and the contents of nutrition and oxygen in watermass. A careful study on the development of the Cambrian and Ordovician piperocks suggests that the decrease of nearshore siliciclastic sediments and the low contents of oxygen and nutrition in the watermass may have contributed to the decline of piperocks in Middle and Late Cambrian.

关键词： Piperock Skolithos Cambrian Ordovician temporal distribution Qiaojia northeastern Yunnan

CeO_(2)/MMT纳米复合材料的制备及其可见光催化氧化性能研究

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水处理技术 2024年第9期50卷 80-84,97页

作者：李友凤易睿方程商涛肖菡曦遵义师范学院化学化工学院贵州遵义563000

采用沉淀法和水热法合成CeO_(2)/MMT纳米复合材料,利用XRD、SEM、BET和UV-Vis DRS等方法对材料的结构、形貌、织构特性和光吸收性能进行分析。在长弧氙灯照射下,模拟太阳可见光降解四环素,研究降解液pH、CeO_(2)与MMT的质量比、催化剂... 详细信息

采用沉淀法和水热法合成CeO_(2)/MMT纳米复合材料,利用XRD、SEM、BET和UV-Vis DRS等方法对材料的结构、形貌、织构特性和光吸收性能进行分析。在长弧氙灯照射下,模拟太阳可见光降解四环素,研究降解液pH、CeO_(2)与MMT的质量比、催化剂用量及抗生素初始浓度等参数对CeO_(2)/MMT光催化的降解性能的影响。结果发现,CeO_(2)/MMT光催化氧化性能较CeO_(2)的要好,且催化氧化反应宜在酸性溶液中进行,当CeO_(2)与MMT的质量比为2时,取得良好的催化降解效果;随着催化剂用量的增大,催化降解率增大,最佳催化剂用量宜为2.5 g/L;四环素初始质量浓度在0.02 g/L以下,降解效果较好;在最佳工艺条件下,CeO_(2)/MMT对四环素的降解率达95%左右。自由基捕获实验发现,CeO_(2)/MMT可见光催化氧化降解过程中•O_(2)^(-)和h^(+)两个活性基团起主要作用,其催化性能稳定,重复使用效果较好。

关键词： CeO_(2)/MMT 复合材料可见光催化氧化四环素

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工业固废碳化固化淤泥的力学性能及机理研究

河南城建学院学报 2024年第1期33卷 56-63页

作者：方子航王强张俊毅安徽理工大学土木建筑学院安徽淮南232001

为改善淤泥的力学特性,提高其抗变形能力,采用电石渣、粉煤灰与矿渣作为环保固化剂,联合CO_(2)碳化固化淤泥。通过加速碳化试验、无侧限抗压强度试验、X射线衍射(XRD)和电镜扫描(SEM),对比分析不同固化剂掺量、碳化时间、碳化深度对试... 详细信息

为改善淤泥的力学特性,提高其抗变形能力,采用电石渣、粉煤灰与矿渣作为环保固化剂,联合CO_(2)碳化固化淤泥。通过加速碳化试验、无侧限抗压强度试验、X射线衍射(XRD)和电镜扫描(SEM),对比分析不同固化剂掺量、碳化时间、碳化深度对试样力学性能和微观结构的影响。结果表明:碳化6 h试样抗压强度得到明显提升,提升幅度为16%~25%;试样强度随着碳化时间先增加后减小,最佳碳化时间为6 h左右;碳化6 h后的pH值从11~14降低到10~12;固化淤泥碳化深度与碳化时间的平方根近似为线性关系;碳化后试样破坏,应变基本不变,但峰值应力明显增大,碳化试样变形模量高于未碳化试样;工业固废碳化固化淤泥试样所生成的水化产物为CaCO_(3)晶体,以针状的文石和方形的方解石形式存在,共同构建土体内部骨架,形成非常密实的交叉体系。

关键词：工业固废碳化固化固化淤泥力学特性微观机制

Electrochemical reactions at the electrode/solution interface:Theory and applications to water electrolysis and oxygen reduction

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Science China Chemistry 2010年第3期53卷 542-551页

作者： fang, Ya Hui liu, Zhi Pan Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials Department of Chemistry Fudan University Shanghai 200433 China

Theoretical simulations on complex electrochemical processes have been developed on the basis of the understanding in electrochemistry,which has benefited from quantum mechanics *** article reviews the recent progress on the theory and applications in *** representative reactions,namely water electrolysis and oxygen reduction,are selected to illustrate how the theoretical methods are applied to electrocatalytic *** microscopic nature of these electrochemical reactions under the applied potentials is described and the understanding of the reactions is *** thermodynamics and kinetics of the electrochemical reactions affected by the interplay of the electrochemical potential,the bonding strength and the local surface structure are addressed at the atomic level.

关键词： density functional theory electrode/solution interface water electrolysis oxygen reduction reaction review

基于改进连通域检测算法的电力工程图纸识别技术

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沈阳工业大学学报 2024年第4期46卷 361-366页

作者：樊冬梅严文豆梁毅刘巍巍浙江大学电气工程学院浙江杭州310027 广东电网有限责任公司广州供电局广东广州510180

针对电力工程图纸识别中存在无法整体标记粘连字符以及标记效率较低的问题,提出了基于数学形态膨胀处理及简化决策树的连通域标记算法。利用可灵活设定的结构元素对输入图像进行膨胀处理,实现了对粘连字符的整体标记;通过分析相邻像素... 详细信息

针对电力工程图纸识别中存在无法整体标记粘连字符以及标记效率较低的问题,提出了基于数学形态膨胀处理及简化决策树的连通域标记算法。利用可灵活设定的结构元素对输入图像进行膨胀处理,实现了对粘连字符的整体标记;通过分析相邻像素的各种可能性,设计了一种基于简化决策树的高效连通域标记算法,进而提升了电力工程图纸的识别效率。仿真结果表明,与传统方法相比,所提算法在实现整体标记粘连字符的同时,显著提高了算法的执行效率,其执行时间约为传统方法的1/2。

关键词：电力工程图纸字符定位字符提取连通域标记粘连字符决策树简化数学形态膨胀标记效率

Construction of optimal supersaturated designs by the packing method

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Science China Mathematics 2004年第1期47卷 128-143页

作者： fang Kaitai GE Gennian liu Minqian Department of Mathematics Hong Kong Baptist University Hong Kong China Department of Mathematics Zhejiang University Hangzhou 310027 China Department of Statistics Nankai University Tianjin 300071 China

A supersaturated design is essentially a factorial design with the equal occurrence of levels property and no fully aliased factors in which the number of main effects is greater than the number of runs. It has received much recent interest because of its potential in factor screening experiments. A packing design is an important object in combinatorial design theory. In this paper, a strong link between the two apparently unrelated kinds of designs is shown. Several criteria for comparing supersaturated designs are proposed, their properties and connections with other existing criteria are discussed. A combinatorial approach, called the packing method, for constructing optimal supersaturated designs is presented, and properties of the resulting designs are also investigated. Comparisons between the new designs and other existing designs are given, which show that our construction method and the newly constructed designs have good properties.

关键词： Kirkman triple systems, orthogonality, packing design, resolvability, supersaturated design.

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鸭嘴式谷子穴播排种器设计与试验

农机化研究 2024年第10期46卷 111-119页

作者：刘华钰衣淑娟陈涛陶桂香毛欣黑龙江八一农垦大学工程学院黑龙江省大庆163319

针对现有谷子排种器条播时重播严重的问题,结合农艺要求,设计了一种鸭嘴式谷子穴播排种器,并分析了排种器的工作过程,确定了排种器与鸭嘴式扎穴器的组合以及排种器转速、取种管直径、取种管角度。采用响应面优化试验,分析了排种器转速... 详细信息

针对现有谷子排种器条播时重播严重的问题,结合农艺要求,设计了一种鸭嘴式谷子穴播排种器,并分析了排种器的工作过程,确定了排种器与鸭嘴式扎穴器的组合以及排种器转速、取种管直径、取种管角度。采用响应面优化试验,分析了排种器转速、取种管直径、取种管角度对穴粒数合格率、漏播率及重播率的影响,结果表明:在取种管角度为55°、取种管直径为8.5 mm、排种器转速为60r/min时,穴粒数合格率为96.70%,漏播率为1.74%,重播率为1.56%,排种性能较优。

关键词：谷子穴播排种器鸭嘴式机构

基于APCS-MLR和PMF的污灌与工业复合区农田土壤重金属来源解析

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环境科学 2024年第8期45卷 4812-4824页

作者：刘德新孟凡磊段海静李一蒙马建华河南大学地理与环境学院开封475004 河南大学黄河中下游数字地理技术教育部重点实验室开封475004 河南大学土壤重金属污染控制与修复工程研究中心开封475004

基于开封市污灌与工业复合区农田表土样品,测定8种重金属(Cr、Ni、Cu、Zn、Cd、Pb、As和Hg)含量,利用绝对因子得分-多元线性回归(APCS-MLR)模型和正定矩阵因子分解(PMF)模型,结合相关性分析和系统聚类分析对土壤重金属来源和贡献率进行... 详细信息

基于开封市污灌与工业复合区农田表土样品,测定8种重金属(Cr、Ni、Cu、Zn、Cd、Pb、As和Hg)含量,利用绝对因子得分-多元线性回归(APCS-MLR)模型和正定矩阵因子分解(PMF)模型,结合相关性分析和系统聚类分析对土壤重金属来源和贡献率进行解析.结果表明:①研究区ω(Cr)、ω(Ni)、ω(Cu)、ω(Zn)、ω(Cd)、ω(Pb)、ω(As)和ω(Hg)平均值分别为52.19、25.00、42.03、323.53、1.79、53.45、9.43和0.20 mg·kg^(-1),其中Cr、Ni和As低于潮土背景值,Cu、Zn、Cd、Pb和Hg高于潮土背景值.②8种重金属有4种来源:自然源、农业污水灌溉源、工业大气沉降源和交通运输源,Cr和Ni主要为自然源,Cu、Zn、Cd和Pb主要为农业污水灌溉和交通运输,As主要为自然源和农业污水灌溉,Hg主要为工业大气沉降.③APCS-MLR和PMF源解析结果表明工农业活动是研究区土壤重金属的主要来源.研究区9个采样小区APCS-MLR平均贡献率为76.01%(自然源和农业污水灌溉源)、22.71%(工业大气沉降源和交通运输源)和1.28%(未知源),PMF平均贡献率为59.66%(自然源和农业污水灌溉源)和40.34%(工业大气沉降源和交通运输源),其中LZ、XZ、NLT、PT、YLZ和BC的两种模型源解析结果基本一致,WL在APCS-MLR模型更优,SG和QT在PMF模型更优.研究结果可为土壤重金属污染防治和环境修复提供科学依据.

关键词：污灌与工业复合区农田土壤绝对因子得分-多元线性回归(APCS-MLR) 正定矩阵因子分解(PMF) 源解析