基于C/S结构的上机管理信息系统实现方法

本文以上机管理信息系统的开发为背景,介绍基于Ｃ/Ｓ结构的管理信息系统的实现方法。     

不同加载角T形钢管混凝土压弯承载力研究

采用有限元软件ABAQUS建立了不同加载角T形带肋和多室钢管混凝土压弯构件的计算模型,数值计算结果与试验结果吻合良好。对影响T形钢管混凝土柱水平荷载P-水平位移Δ关系曲线的参数进行分析,结果表明:加载角为0°时,T形钢管混凝土构件的承载力最低,在67.5°负向加载时,构件的承载力最大,比0°加载角构件大13%左右,加载角为45°~90°间承载力总体上差别不大。随着钢管屈服强度、混凝土抗压强度、钢管长厚比、带肋和多室T形钢管混凝土构件在斜向加载的承载力增加,在传统钢管混凝土基础上,提出了适用于不同加载角带肋和多室T形钢管混凝土压弯构件的承载力设计方法,简化计算公式与有限元结果、试验结果均吻合较好。     

Numerical Simulation of Dynamic Response and Collapse for Steel Frame Structures Subjected to Blast Load

The progressive collapse of steel frame structures under the blast load was investigated using LS-DYNA. The multi-material Eulerian and Lagrangian coupling algorithm was adopted. A flu-id-structure coupling finite element model was established which consists of Lagrange element for simulating steel frame structures and concrete ground, multiple ALE element for simulating air and TNT explosive material. Numerical simulations of the blast pressure wave propagation, struc-tural dynamic responses and deformation, and progressive collapse of a five-story steel frame structure in the event of an explosion near above ground were performed. The numerical analysis showed that the Lagrangian and Eulerian coupling algorithm gave good simulations of the shock wave propagation in the mediums and blast load effects on the structure. The columns subjected to blast load may collapse by shear yielding rather than by flexural deformation. The columns and joints of steel beam to column in the front steel frame structure generated enormous plastic defor-mation subjected to intensive blast waves, and columns lost carrying capacity, subsequently lead-ing to the collapse of the whole structure. The approach coupling influence between struc-tural deformation and fluid load well simulated the progressive collapse process of structures, and provided an effective tool for analyzing the collapse mechanism of the steel frame structure under blast load.     

Numerical Simulation of Dynamic Response and Collapse for Steel Frame Structures Subjected to Blast Load

The progressive collapse of steel frame structures under the blast load was investigated using LS-DYNA.The multi-material Eulerian and Lagrangian coupling algorithm was adopted.A fluid-structure coupling finite element model was established which consists of Lagrange element for simulating steel frame structures and concrete ground,multiple ALE element for simulating air and TNT explosive material.Numerical simulations of the blast pressure wave propagation,structural dynamic responses and deformation,and progressive collapse of a five-story steel frame structure in the event of an explosion near above ground were performed.The numerical analysis showed that the Lagrangian and Eulerian coupling algorithm gave good simulations of the shock wave propagation in the mediums and blast load effects on the structure.The columns subjected to blast load may collapse by shear yielding rather than by flexural deformation.The columns and joints of steel beam to column in the front steel frame structure generated enormous plastic deformation subjected to intensive blast waves,and columns lost carrying capacity,subsequently leading to the collapse of the whole structure.The approach coupling influence between structural deformation and fluid load well simulated the progressive collapse process of structures,and provided an effective tool for analyzing the collapse mechanism of the steel frame structure under blast load.     

Compressive Strength of Hydrostatic-Stress-Sensitive Materials at High Strain-Rates

Many engineering materials demonstrate dynamic enhancement of their compressive strength with the increase of strain-rate, which have been included in material models to improve the reliability of numerical simulations of the material and structural responses under impact and blast loads. The strain-rate effects on the dynamic compressive strength of a range of engineering materials which behave in hydrostatic-stress-sensitive manner were investigated. It is concluded that the dynamic enhancement of the compressive strength of a hydrostatic-stress-sensitive material may include inertia-induced lateral confinement effects, which, as a non-strain-rate factor, may greatly enhance the compressive strength of these materials. Some empirical formulae based on the dynamic stress-strain measurements over-predict the strain-rate effects on the compressive strength of these hydrostatic-stress-sensitive materials, and thus may over-estimate the structural resistance to impact and blast loads, leading to non-conservative design of protective structures.     

K/Na-Mo复合变质对M2高速钢组织和性能的影响

用K／Na-Mo复合变质剂对M2铸造高速钢进行变质处理,对试样进行组织分析及力学性能测试．结果表明,随着K／Na-Mo复合变质剂的加入,M2高速钢中铸态碳化物趋于断网,骨状晶转变为等轴晶,组织得到了优化,同时M2高速钢的韧性明显提高,硬度和红硬性也有所改善．     

梁启超与五卅运动

五卅惨案发生后,梁启超作为一介国士,以维护国家利益为己任,多次向政府和国人病陈沪案解决方略,提出了一些很有见地的主张,然而非但没有引起政府和国人的重视,反而遭致许多误解。梁启超不以为悔,其拳拳爱国之心表现于字里行间。     

竖向电渣压力焊施工操作方法特点

竖向电渣压力焊是一种综合效益极好的技术,具有焊接工艺操作简单、速度快、成本低等特点,应在多层和高层框架结构竖向钢筋连接中大力推行.     

Innovation, regional knowledge spillovers and R&D cooperation

We investigate the impact of knowledge spillovers and R&D cooperation on innovation activities in three German regions. We begin by estimating the knowledge-production function in order to test for interregional difference with regard to the efficiency of innovation activities. In a second step, we analyze the contribution of spillovers from R&D effort of other private firms and of public research institutions to explain these differences. The inclusion of variables for R&D cooperation in the model indicates that R&D cooperation is only of relatively minor importance as a medium for knowledge spillover.     

Investigating the interaction and mutual dependence between science and technology

Literature on the economics of science and technology (S&T) suggests not only that technological innovation demands the expansion of the institutional borders between universities, research institutes, industrial companies and the financial system, but also that science leads as well as follows technology. Medical innovation in particular is very dependent on scientific research, which represents a source of information that impels the productive sector. The latter introduces a series of questions that motivate the researchers in their attempt to understand how the human body reacts to certain products and therapies. This paper analyses the pattern of S&T interaction for both the national system of innovation (NSI) and the health innovation system. The panel data and simultaneous equations models analyze the interaction between S&T. The theory about the existence of a mutual dependence between them has been confirmed, which means that science moves technology and technology also influences scientific development. The estimated models, which use data from scientific papers and patents as proxies of science and technology, represent just the tip of the iceberg called NSI, known as a multifaceted and complex institutional arrangement.