Highly textured and strongly anisotropic TiB2 ceramics prepared using magnetic field alignment (9T)

Highly textured TiB₂ ceramics were prepared by slip casting an aqueous suspension in a magnetic field of 9 T, followed by sintering using Field Assisted Sintering Technology (FAST). Particle size refinement by ball milling improved both the degree of texturing and densification of the material (RD > 98 %). The sintered material exhibited a Lotgering orientation factor of 0.90, with the c-axis of TiB₂ oriented parallel to the magnetic field and FAST pressing direction. The texturing effect induced by the uniaxial pressing was negligible. The textured TiB₂ material exhibited a significant anisotropy in mechanical properties; the values of hardness and indentation elastic modulus measured along directions transverse to the c-axis of TiB₂ were 37 % and 13 % higher than the ones measured along the c-axis direction. Moreover, the specific wear rate of a surface of textured TiB₂ parallel to the field was one order of magnitude lower than a surface perpendicular to the field.     

液晶光学相阵列相移单元的电压-相移特性

液晶光学相阵列是一种新型的光学相位调制器件,为分析器件中相移单元的电压-相移特性,建立了液晶相移单元的数学模型,并提出了一种混合差分迭代算法。该算法根据液晶分子在电场作用下的物理变化过程,在指向矢与电位的耦合迭代过程中,采用追赶法计算相移单元中的电位分布。根据该算法对相移单元中液晶指向矢的分布进行了仿真计算,进而对取向膜厚度、预倾角和液晶盒厚度对器件的电压-相移特性的影响进行了分析。结果表明,当电压处于阈值电压与饱和电压之间时,取向膜厚度对液晶的电压-相移特性的影响比较明显。     

初始对准中常规六状态卡尔曼滤波器的应用

建立了常规六状态滤波器误差方程,进行了kalman滤波仿真,得到航向、姿态角误差和陀螺漂移误差量,进行补偿。仿真结果显示常规滤波器在初始对准中取得了较好的效果。     

Technological Innovation: Regaining the Competitive Edge

ABSTRACT

Global competition has become a business reality. To become competitive, we must improve the rate at which new technical concepts are incorporated into our products and processes. This article describes the sources and driving forces of innovation and the creative environment that the engineering manager must consider to increase the innovative productivity of the organization. Managers must also recognize the impact that the technical education system has on future innovative productivity and take the initiative to improve it. They must emphasize the importance of systems and process research and support such programs. In addition, idea generation must be considered just as important as analysis to the long-term success of the technological enterprise.     

Internetressourcen zu IT/Business Alignment

IT/Business Alignment IT/Business Alignment has become a key issue for many companies. Therefore a lot of companies, institutions and universities have published documents about this topic. This paper is intended to give an overview of these resources found in the Internet.

     

SAMBO—A system for aligning and merging biomedical ontologies

Due to the recent explosion of the amount of on-line accessible biomedical data and tools, finding and retrieving the relevant information is not an easy task. The vision of a Semantic Web for life sciences alleviates these difficulties. A key technology for the Semantic Web is ontologies. In recent years many biomedical ontologies have been developed and many of these ontologies contain overlapping information. To be able to use multiple ontologies they have to be aligned or merged. In this paper we propose a framework for aligning and merging ontologies. Further, we developed a system for aligning and merging biomedical ontologies (SAMBO) based on this framework. The framework is also a first step towards a general framework that can be used for comparative evaluations of alignment strategies and their combinations. In this paper we evaluated different strategies and their combinations in terms of quality and processing time and compared SAMBO with two other systems.     

A relation between edit distance for ordered trees and edit distance for Euler strings

We consider a relationship between the unit cost edit distance for two rooted ordered trees and the unit cost edit distance for the corresponding Euler strings. We show that the edit distance between trees is at least half of the edit distance between the Euler strings and is at most 2h+1 times the edit distance between the Euler strings, where h is the minimum height of two trees. The result can be extended for more general cost functions.     

在大学英语写作中运用过程教学法的基本构思

英语教学正在向重视培养语言应用能力的方向发展,英语写作是体现英语应用能力的一个重要方面.过程教学是国外普遍采用的写作教学方法,它是沿着写作过程的三个阶段进行教学的.它不但能指导学生顺利通过四、六级写作考试,而且对考研、托福等考生了解英语写作的一般规律也有借鉴价值.     

英语科技文体的语言特征

英语科技文体语法规范,措辞严谨,词汇的术语性强。与其它各种文体相比,其语言特征主要表现在:术语性词汇、主导形时态、被动句式、超长句等的出现频率较高。