管线用高强韧性宽厚钢板的开发

本文回顾了舞钢高强韧性管线用宽厚钢板的研制开发过程，并结合生产工艺，对钢板性能作了全面分析，指导了钢管线钢的生产。舞钢X70级管线钢有较高的断裂韧性、良好的可焊性以及抗SSCC、HIC性能。舞钢正在进行技术改造，以进一步改善组织，提高性能、满足西气东输要求。     

热处理工艺对冲击曲线的影响

通过ＳＡ５１５Ｇｒ．７０钢的不同温度正火和１３ＭｎＮｉＭｏＮｂＲ钢正火不同温度回火试样的示波冲击试验，研究了不同热处理工艺对冲击曲线的影响。     

Extrapolated galerkin time finite elements

A new time finite-element method based on the extrapolation technique and the Galerkin time finite-element method is presented. In this method, the second-order governing differential equations of motion for dynamic problems are rewritten as a set of first order differential equations in state space. The standard Galerkin method is then employed for the temporal discretization. The algorithm is first-order accurate only. Based on the first-order Galerkin time finite-element formulation, the extrapolation technique is introduced to improve the order of accuracy. It is achieved by expressing the numerical amplification matrix of higher-order algorithm as a linear combination of the basic amplification matrices evaluated at selected instances of time. The matrices are combined with different weighting factors. The pairs of the selected instance of time and the corresponding weighting factors are free parameters. Unconditionally stable higher-order accurate formulations can be derived by properly choosing the free parameters. Algorithms up to fourth-order accurate are presented in this paper. Detailed analyses on stability, numerical dissipation and numerical dispersion are also given. Comparisons of the present algorithms with some well-known time-integration methods are presented to demonstrate the versatility of the present method, in particular its accuracy in the higher-order formulations.     

Representation and uniformization of algebraic transductions

This paper explores different means of representation for algebraic transductions, i.e., word relations realized by pushdown transducers. The relevance of this work lies more in its point of view rather than any particular result. We are aiming at giving specific techniques for obtaining, or perhaps explaining, decompositions of algebraic (and incidentally, rational) relations, relying solely on their “machine” definition rather than some complex algebraic apparatus. From this point of view, we are hoping to have demystified the heavy formalism employed in the present literature. Some of the novelties of our work are: the use of “stack languages” and “embeddings,” which eliminate the need of arbitrary context-free languages in our characterizations, the study of uniformizations for algebraic transductions and the use of the so-called stack transductions for exposing the anatomy of pushdown transducers.This work was supported by the Natural Science and Engineering Research Council of Canada grants R220259 and OGP0041630.     

宝鸡民营钛工业发展现状

介绍了宝鸡民营钛工业在新材料、新技术、新设备、新应用方面的进展,提供了市场需求与发展前景方面的相关信息,并对中小型钛加工企业的发展提出建议。     

激光光束质量因子的研究进展

本文详细分析了各种光场下光束质量M2因子。在不同的场中,A.E.Siegman当初所定义的M2因子,已经有了很大的变化,因而M2因子的特性也与当初不同,不仅M2因子可以大于等于1,而且可以小于1,甚至小于0。其反映的物理意义,也从经典场中的衍射极限倍数,变化为非经典场中的准直性量度以及对空间相干性的某些反映。此外还列举并分析了几种特殊的光束质量因子,最后讨论了M2因子应用的问题并指出了其局限性。     

凹凸科技正式进军网络安全

网络安全及电源管理芯片供应商凹凸科技于2月28日正式宣布跻身网络安全领域,并在当天的酒会上向中国用户隆重推介凹凸科技在网络安全领域的独特理念和全新方案;同时对外亮相的还有两款代表性的成熟产品—ASIC防火墙SifoWorks和SSLVPN产品Succendo。凹凸科技成立于1995年4月,在模拟与数字集成电路方面拥有强大的研发队伍和能力,是移动及网络安全通信系统方面的ASIC技术专家,其产品客户广泛遍布于全球各主要电脑、消费电子、工业及移动通信等重要领域。随着混合式防火墙等安全产品的市场需求发展,在ASIC设计领域拥有独特能力和品质保…     

发展靠改革 改革求创新——访上海烟草工业印刷厂俞志康厂长

从中央对“十一五”规划的部署来看,我国的发展又进入了一个新的历史阶段。规划强调改变经济的增长方式,提高资源利用率,调整经济增长与资源环境制约之间的矛盾,继续实施产业结构的调整,对企业兼并改组的力度还将加强,钢铁、石油、石化、烟草等均在其列。占国家税收重头的烟草业,自2003年就迎来一次“地震”式的重组。2006年1月11日,国家烟草专卖局又宣布,正式启动“打造十大烟草航母集团”的计划,将对现有44家烟草企业进行整合,组建成以品牌为支撑的十大烟草航母集团。这对长期以来依靠烟草企业而生存发展的烟草印刷企业来说,如何面对这种改组,并规划好自身的发展,采取哪些应对策略与措施,也就成了那些不甘寂寞,且仍想稳操胜券的烟印企业领导们关注的焦点。其实,在钢铁、石油、石化以及其他大型企业集团长期庇护下的印刷企业又何止少数?这些企业的领导人也该从“手捧铁饭碗,稳坐太师椅”的状态中有所觉醒、有所思考吧?所以这次我们采访上海烟草印刷厂领导的目的,说白了,绝不仅仅是为了报道上海烟印自强不息的光辉篇章,而是通过这一报道,给面临行业整合改组的印企领导们奉上一道醒酒菜。毕竟在葡萄美酒前自我陶醉的好景不会太久了,还是尽快作好优胜劣汰的竞争准备吧。     

Closed-form solutions for one-dimensional inhomogeneous anisotropicmedium in a special case. I. Direct scattering problem

An analytical formulation is presented for the direct scattering problem of one-dimensional (1-D) inhomogeneous anisotropic medium in a special case. This method gives nonlinear differential equations for the reflection coefficients of the anisotropic medium. Applying the discontinuity condition of the dielectric parameters at the interface of the medium with free space, approximate closed-form solutions for the reflection coefficients are obtained. Numerical examples show the validity of the method