Numerical Simulation of Response of SRC Columns Subjected to Blast Loading

The dynamic characteristics and failure modes of steel reinforced concrete (SRC) columns subjected to blast loading are complicated because of the transient stress wave in the SRC columns and the interaction between steel and concrete. This paper presents a numerical simulation of the response of SRC columns subjected to blast loading using hydrocode LS-DYNA. In the numerical model, a sophisticate concrete material model (the Concrete Damage Model) is employed with consideration of the strain rate effect and the damage accumulation. An erosion technique is adopted to model the spalling process of concrete. The possible failure modes of SRC columns are evaluated. It is observed that the failure of SRC columns subjected to blast load can generally be classified into three modes, namely, a direct failure in concrete body due to the stress wave, a transverse shear failure near the support sections due to the high shear force, and a flexural failure pertaining to large local and global deformation of the reinforcing steel.     

中国山水画笔墨认识

中国山水画历史悠久,山水画笔墨技术从产生到成熟,建构了独特的绘画符号。“程式化”笔墨因此而确立。没有“程式”就不能成为国画。     

运动性骨骼肌损伤时的某些组织学、生化学及力学变化

运动性骨骼肌损伤是:体育运动中非常普遍的现象,在出现肌肉延迟性疼痛的同时,伴有肌组织结构和功能及血液生化成分的改变,表现为细胞肿胀、肌力下降、血中肌肉酶活性升高等等。研究发现肌组织的这种结构与功能的变化是暂时的,它可随运动员对某一运动形式,负荷的适应而逐渐消失。运动性骨骼肌损伤的诱发机理并不十分明了,目前认为很可能与肌组织的机械应激有关。     

基于空间光调制器和CCD的衍射光学实验系统

开发了基于空间光调制器(SLM)和数码摄像机(CCD)的新型衍射光学实验系统。用SLM取代掩模板,用AutoCAD、Matlab等绘图软件,在PC机屏幕上绘制小孔、狭缝以及复杂的几何图形,再通过接口电路传输到SLM。用扩束准直后的激光束照射SLM,通过透镜在其后方借助CCD实时观察各图案的衍射图像,可对其菲涅耳与夫琅和费衍射特性进行观察和在线测量分析。该系统能够完成典型几何图案、小孔狭缝、多种形状随机分布孔等三类对象的衍射实验。系统实时性好,衍射图像可存储和处理,灵活方便。     

谈风景画中的光与色彩

在分析风景画中的光与色彩和印象派画家的作品及理论观点的基础上,研究了光是塑造风景画色彩的本源。针对光对风景画色彩语言的表现与创作和光与色是风景画家主观世界的绘画表现语言问题进行了进一步的探讨。     

Evaluation of the antioxidant effects of four main theaflavin derivatives through chemiluminescence and DNA damage analyses

Theaflavins (TFs) are the dimers of a couple of epimerized catechins, which are specially formed during black tea fermentation. To explore the differences among four main TF derivatives (theaflavin (TF₁), theaflavin-3-gallate (TF₂A), theaflavin-3′-gallate (TF₂B), and theaflavin-3,3′-digallate (TF₃)) in scavenging reactive oxygen species (ROS) in vitro, their properties of inhibiting superoxide, singlet oxygen, hydrogen peroxide, and the hydroxyl radical, and their effects on hydroxyl radical-induced DNA oxidative damage were systematically analyzed in the present study. The results show that, compared with (−)-epigallocatechin gallate (EGCG), TF derivatives were good antioxidants for scavenging ROS and preventing the hydroxyl radical-induced DNA damage in vitro. TF₃ was the most positive in scavenging hydrogen peroxide and hydroxyl radical, and TF₁ suppressed superoxide. Positive antioxidant capacities of TF₂B on singlet oxygen, hydrogen peroxide, hydroxyl radical, and the hydroxyl radical-induced DNA damage in vitro were found. The differences between the antioxidant capacities of four main TF derivatives in relation to their chemical structures were also discussed. We suggest that these activity differences among TF derivatives would be beneficial to scavenge different ROS with therapeutic potential.     

TS-10C全固态中波广播发射机报警系统的改进

介绍ＴＳ—１０Ｃ全固态中波广播发射机控制监测器功能,阐述对其报警系统改进方法．     

微小长度变化量的实验研究

总结了光杠杆放大法、千分表测量法、光的干涉测量法和光的衍射测量法测量微小长度变化量的方法,通过对实验装置进行相应的改造与组装,并用其测量原理和方法以及相关的实验装置对金属受热时的微小伸长量及线胀系数进行了相应的测定,同时对实验结果和误差进行了比较与分析。实验表明,4种测量方法中千分表测量法的相对误差和标准偏差均接近最小值,是4种方法中最理想的测量方法。该实验也有利于激发学生的创新意识,培养他们的研究潜能。     

震后重建推进住宅产业化模式研究

技术和经济相结合,先采用有限元软件建立了典型多层轻钢结构模型,通过计算分析了抗震性能、较优跨度和经济用钢量。再将该模型的全寿命周期成本与传统住宅造价进行比较分析,旨在为灾后重建以及住宅产业化的推广提供参考。     

论我国危害列车运行安全犯罪的立法完善

我国刑法关于危害列车运行安全犯罪的立法规定在维护铁路运输安全方面发挥着重要作用,然而和西方国家的立法相比,存在着法定起点刑过高、语言表述模糊以及过失危险犯缺失等方面的不足,导致维护列车运行安全的法律保护体系并未充分的形成和发挥作用。