并行MLFMA分布层的构造及其负载均衡

研究了并行多层快速多极子算法（MLFMA）的分布层,提出了一种衡量其负载不均衡程度的方法,并在此基础上提出了分布树的一种新的构造算法。通过预先估算按分布层的不同层均分所得分布层的负载不均衡度,选取了一种负载不均衡度较小的方法来构造分布树。实验结果表明,该算法相比传统的按分布层的最细层均分所得分布树的算法,能更为有效地提高整个多层快速多极子算法的并行效率。     

A modified advancing layers mesh generation for thin three-dimensional objects with variable thickness

A method of generating modified advancing layers mesh is proposed. In this paper the mesh generation process of semi-unstructured prismatic/tetrahedral mesh is presented for relatively thin three-dimensional geometries with variable thickness, as in the case of injection molding analysis. Prismatic meshes are generated by offsetting initial surface triangular meshes. During the mesh generation process, mesh quality is efficiently improved with the use of a new node relocation method. Finally, tetrahedral meshes are automatically generated in the rest of the domain. The mesh generating capability of the proposed algorithm is demonstrated with the several practical test cases.     

改进颜色融合的医学图像彩色化技术

彩色化后的医学图像能清晰体现患者病灶信息有利于医患沟通。提出改进颜色融合的医学图像彩色化方法,首先利用基于KNN的图像前背景区分算法,强化病灶区域的边界信息;然后以此为约束条件,只需提供简单的着色输入;最后将边界能量引入颜色融合方法,得到较好的着色结果。着色图像保持了原图的灰度信息不变,增加了彩色标记图像的颜色和真实感。实验结果表明,该算法具有较高的精确度,可有效的应用于医学图像彩色化处理。     

用Java开发CORBA式应用程序

采用Java与CORBA组合方式编写客户机 /服务器应用程序 ,使其应用程序功能更强、更加灵活。这样既可允许开发者利用已有的代码保护投资 ,另一方面又可充分发挥Java编程语言的优势 ,利用JDBC获得相关信息 ,该方法将用CORBA生成一个真正的三层应用程序。     

Tuning the alignment of liquid crystals by means of nano‐structured surfaces (Invited Paper)

Abstract— The solid‐surface/liquid‐crystal interactions, defining the field‐free alignment of the liquid crystal in conventional liquid‐crystal displays, are playing a vital role in their optical appearance and performance. Nano‐scale changes in the solid‐surface structure induced by light have been recently shown to affect the anchoring strength and the easy‐axis direction. Fine tuning of the anchoring strength is also demonstrated by nano‐structuring of the Langmuir‐Blodgett monolayer employed as liquid‐crystal alignment layers promoting homeotropic orientation. On the basis of nano‐engineering of the surface alignment properties, two novel alignment concepts have been introduced: electrically commanded surfaces (ECS) and high‐performance alignment layers (HiPAL). Nano‐structured polymers related to these concepts have been designed, synthesized, and used as materials for alignment layers in LCDs. ECS materials belong to the category of active alignment materials designed to mediate switching of the liquid crystal, whereas the HiPAL materials make possible the control of the molecular tilt angle in a broad range, from 0° to 90°, and they seem to enable the control of the anchoring strength as well. The nano‐structured alignment materials are strong candidates for implementation in a new generation of advanced liquid‐crystal displays and devices.     

基于模糊神经网络的煤层冲击地压预测模型研究

煤层冲击地压是煤矿重大灾害之一。冲击地压的发生是由多方面因素造成的,具有模糊性、动态性,表现为一个复杂的非线性动力学过程,这使得冲击地压预测系统的数据处理不能按照常规的线性系统法进行处理。文章提出了多源信息融合的模糊神经元网络算法,且基于势场拓扑层次聚类融合FCM算法的聚类思想,将模糊集合理论引入神经元网络,构成基于多判据信息融合的模糊神经元网络模型,并对该网络进行了优化。通过仿真试验,验证了该模型的有效性。     

GIS域状图层可交换文件的C＋＋编程转换——以ARC／INFO向MapInfo转换为例

域状图是GIS处理或操作的基本对象之一,大量复杂的域状图层靠备拓扑运算功能的GIS自动生成,编码严谨、档注完备,是单机和网络上数据分析可视化应用急需的信息源。为了信息共享,不同GIS平台之间,GIS与GIS应用软件之间常进行可交换文件的格式转换,以ARC／INFO向MapInfo文件转换为例,通过简析它们相应的文件结构,简介了C＋＋环境下的数据转换编程思路、流程、相关的数据结构和解决方法,为日常办公电子表格应用中的区域状图层或图件自动插入奠定了基础。     

Study of Nano-Porous Silicon with Low Thermal Conductivity as Thermal Insulating Material

Recently discovered phenomenon of extremely low thermal conductivity of nano-porous silicon (nano-PS) is discussed in detail. A theoretical model describing specific mechanisms of heat transport in as-prepared and oxidized nano-PS layers is described. The theoretical estimations are in a good agreement with experimental data obtained earlier. The low thermal conductivity values allow to use this promising material as thermal insulator in microsensors and microsystems. To ensure an efficient thermal isolation, a nano-PS layer has to be as thick as possible and mechanically stable. We describe here the procedures to form thick (up to 200 m) and stable nano-PS layers. Distribution of Si oxidized fraction along the layer thickness after thermal oxidation in dry O₂ atmosphere at 300°C during 1 h is studied.     

海河隧道工程防洪影响分析

海河隧道线路全长2 3034 m,其中主河道沉管段长240 m,沉管断面宽度374 m,高98 m,共设置两节,每节120 m。河道沉管段采用水中沉管法施工。管段安装会对河道的防洪安全产生较大的影响,故须对河段的水沙条件有严格的要求。本文采用三维分层水流泥沙数学模型,通过错层处理,较好地解决了同层网格产生急剧变化,在突变点处隔层网格物理量的影响远大于层间网格的影响问题。对隧道管段悬浮状态、沉放过程中的过流能力、水流流态和河段水流泥沙运移规律进行了深入分析,提出管段对河段水沙的影响程度及解决措施。本研究拓展了三维分层水流泥沙数学模型的应用范围,为保证工程施工安全提供了理论基础。