虚拟全景的链接——“虚拟现实”系列之三

该文通过实例介绍了虚拟全景之间、虚拟现实全景与URL以及静止图片之间的链接技术     

Effects of finishing rolling temperatures and reduction on the mechanical properties of hot rolled multiphase steel

Effects of finishing rolling temperatures and reduction on the mechanical properties of hot rolled multiphase steel were investigated. Thermo-mechanical control processing (TMCP) was conducted by using a laboratory hot rolling mill, in which three different kinds of finishing rolling temperatures and reduction and various austempering times were applied. The results showed that polygonal ferrite, granular bainite and larger amount of stabilized retained austenite can be obtained by controlled rolling processes, and that the strain-induced transformation to martensite from the retained austenite can occur gradually when the steel is deformed during tensile test. Mechanical properties increase with decreasing finishing rolling temperature and increasing amount of deformation. The most TRIP (transformation induced plasticity) effect, and ultimate tensile strength (UTS), total elongation (TEL) and the product of ultimate tensile strength and total elongation (UTS×TEL) are obtained at 20 min.     

Numerical Modeling of Response and Damage of Masonry Walls to Blast Loading

To model the damage process of masonry walls under blast loading, a dynamic continuum damage material model is constructed for brick and mortar separately. The degradation of both the stiffness and strength are governed by a damage variable. By using the proposed material model, damage and fragmentation of a typical masonry wall under blast loading at different scaled distances is calculated. The hazard level of the masonry wall to blast loading is evaluated by analyzing the numerical results.     

Mitigation of Blast Effects on Aluminum Foam Protected Masonry Walls

Terrorist attacks using improvised explosive devices (IED) can result in unreinforced ma-sonry (URM) wall collapse. Protecting URM wall from IED attack is very complicated. An effective solution to mitigate blast effects on URM wall is to retrofit URM walls with metallic foam sheets to absorb blast energy. However, mitigation of blast effects on metallic foam protected URM walls is currently in their infancy in the world. In this paper, numerical models are used to simulate the per-formance of aluminum foam protected URM walls subjected to blast loads. A distinctive model, in which mortar and brick units of masonry are discritized individually, is used to model the perform-ance of masonry and the contact between the masonry and steel face-sheet of aluminum foam is modelled using the interface element model. The aluminum foam is modelled by a nonlinear elas-toplastic material model. The material models for masonry, aluminum foam and interface are then coded into a finite element program LS-DYNA3D to perform the numerical calculations of response and damage of aluminum foam protected URM walls under airblast loads. Discussion is made on the effectiveness of the aluminum foam protected system for URM wall against blast loads.     

Strength and Toughness of Steel Fibre Reinforced Reactive Powder Concrete Under Blast Loading

The blast resistance of structures used in buildings needs to be investigated due to the increased threat of a terrorist attack. The damage done by Composition B or Powergel to steel fibre reinforced reactive powder concrete (SFRPC) panels and ordinary reinforced concrete (RC) panels of equivalent static flexural strength is compared. A 0.5 kg charge was detonated at a distance of 0.1 m from the 1.3 m×1.0 m×0. 1 m (thick) panels, which were simply supported and spaning 1.3m. Dynamic displacement measurements, high-speed video recording and visual examination of the panels for spall and breach were undertaken. The SFRPC panels withstood the bare charge blast better than the reinforced ordinary concrete panels. Neither type of panel was breached using a 0.5 kg charge. The RC panel exhibited more spalling when Composition B was used. Under successive Composition B loading conditions, the RC panel was breached. In comparison the SFRPC panel was not breached. Exposure to fragmenting charge loading conditions confirmed these performance differences between the SFRPC panel and the reinforced ordinary concrete panel.     

矿渣微粉对混凝土性能影响的试验研究

通过试验，利用不同细度、不同掺量的矿渣微粉等量置换混凝土中的水泥，研究混凝土性能变化趋势，以期达到优化矿渣微粉应用参数和使用效果的目的。试验结果表明：在配制C40混凝土时，矿渣细度控制在500m^2/kg左右，掺量20％∽60％时，混凝土的工作性和力学性能均得到较好的发挥。     

Simulation of Blast and Fragment Loading Using a Coupled Multi-Solver Approach

Simulating blast and fragment loading simultaneously in a single computation requires the combined use of multiple states of the art solvers. A pipe bomb is an example of simple improvised explosive device (IED) that consists of a piece of pipe filled with explosive material and capped at both ends. To simulate the explosion of a pipe bomb and the damage it causes, a coupled multisolver approach based upon finite element and finite volume methods is applied. The numerical calculation presented demonstrates the ability of ANSYS AUTODYN(?) to correctly simulate the threats of lEDs and provides insight into how the most significant physical phenomena affect the results.     

我国高影响力论文产出现状及国际地位

【目的】了解我国高水平科研产出的结构特征和国际科技地位,为我国科技期刊的选题、组稿,科技期刊和科学研究的国际化发展提供参考。【方法】利用ESI数据库对我国热点论文进行全面分析与评价,对比研究我国科研人员参与发表和我国科研人员作为第一作者发表的热点论文的文献计量学特征。【结果】我国入选ESI热点论文数量排名全球第3,主要分布在我国北京、江苏、上海、浙江等地区,与美国、英国、德国、澳大利亚等合作最为密切。【结论】我国高影响力科研产出名列国际前茅,但短期内较难实现全球第一的突破。我国高影响力论文产出状况有助于我们了解我国优质稿源的分布特征和去向,对推动我国学术期刊的国际化发展具有重要意义。     

在计算机硬件实验教学中培养学生各种能力

根据《计算机硬件实验》课不同实验内容按由浅入深分为基本性实验、验证性实验、设计性实验三部分,根据不同的实验内容采用不同的教学方法有侧重地培养学生的各种能力。     

影响铁水预处理脱硫粉剂消耗因素的探讨

通过对影响铁水预处理脱硫粉剂消耗因素的分析,阐述了降低粉剂消耗的措施,以指导实际生产.