挡水结构水下爆炸作用的离心模型试验

水下爆炸包括冲击波和气泡脉动,两者能量相当,均会对结构产生毁伤作用。水下爆炸载荷试验唯有在离心机内才满足相似关系,设计试验时宜在离心机负载范围内尽可能增加模型尺寸以减小边界效应。针对挡水结构,在离心机内布置压力传感器、高速摄像机、加速度计及应变片测试了冲击波、气泡脉动载荷及结构产生的动力响应。通过试验对比了水下爆炸和空爆产生的载荷,分析其引起结构动力响应的差异。对于水下爆炸,重力加速度的增加引起气泡脉动冲量的减小,而气泡脉动产生的峰值应变基本与气泡冲量呈线性关系,因而模拟气泡脉动对结构作用时应考虑重力效应。     

Structure of the Reaction Zone of a Steady Detonation Wave in Dinitrodiazapentane

The massvelocity profiles in 2,4dinitro2,4diazapentane samples of different densities were registered by a laser interferometer and the electromagnetic technique. The reaction time was shown to reach 300 nsec and weakly depend on density, while the pressure in the chemical spike can be twice as high as that at the Chapman–Jouguet point. No special features due to diamond formation were observed in the massvelocity profiles registered in the chemical reaction zone.     

Interaction of a shock pulse with a contact discontinuity

Passing of a triangular moderate-intensity pulse through a constant discontinuity is considered. Decay of the shock wave that passed into the second gas is analyzed. Damping of the detonation wave after burnout of the combustible mixture is discussed. __________ Translated from Fizika Goreniya i Vzryva, Vol. 43, No. 4, pp. 102–107, July–August, 2007.     

Processing and characterization of particles reinforced SiOC composites via pyrolysis of polysiloxane with SiC or/and Al fillers

Polysiloxane loaded with SiC as inert filler, and Al as active filler, was pyrolyzed in nitrogen to fabricate SiOC composites, and the processing and properties of the filled SiOC composites were investigated. Adding SiC fillers could reduce the linear shrinkage of filler-free cured polysiloxane in order to obtain monolithic SiC/SiOC composites. The flexural strength of SiC/SiOC composites reached 201.3 MPa at a SiC filler content of 27.6 vol.%. However, SiC/SiOC composites exhibited poor oxidation resistance, thermal shock resistance and high temperature resistance. Al fillers could react with hydrocarbon generated during polysiloxane pyrolysis at 600 °C and N₂ at 800 °C to form Al₄C₃ and AlN, respectively. The volume expansions resulting from these two reactions were in favor of the reduction in linear shrinkage and the improvement in flexural strength of SiC/SiOC composites. The flexural strength of Al-containing SiC/SiOC composites was 1.36 times that of SiC/SiOC composites without Al at an Al filler content of 20 vol.%. The addition of Al fillers remarkably improved the high temperature resistance and oxidation resistance of SiC/SiOC composites, but not thermal shock resistance.     

基于稀疏表示的单帧运动图像盲复原

提出一种基于稀疏表示的单帧运动盲复原方法,它充分利用自然图像中存在的各种先验知识进行求解。该方法分为模糊核估计和图像修复两个阶段。在估计模糊核时,它运用shock滤波器从模糊图像中预测出清晰边缘,以此指导全局图像的复原,并运用多尺度策略来解决大模糊核问题。在图像修复阶段,运用稀疏表示理论对复原图像进行降噪和重建,最终提高图像复原质量。实验结果表明,在不同噪声和模糊核条件下,该算法能有效消除运动模糊。     

Dynamic Compressibility of Carbamide at Low Pressures

The shock adiabats of pressed carbamide samples with a density of 1.29 g/cm³ and carbamide samples with a bulk density of 0.78 g/cm³ were studied at pressures of 1–14 GPa using an electromagnetic method. In the coordinates D and U, the shock adiabat of pressed carbamide is linear and the shock adiabat of carbamide of bulk density at a pressure of 2.4 GPa is represented as two linear segments: D = 2U at 0.6 < U <1.3 km/sec and D = 0.6 + 1.55U at 1.3 <U < 2.8 km/sec. The possibility of a phase transition in carbamide under shock compression is discussed.     

Strength of Some Grades of Steel and Armco Iron under Shock Compression and Rarefaction at Pressures of 2 – 200 GPa

This paper reports results from a comparative experimental study of the dynamic strength of St. 20 and 09G2S steels (which are of interest as structural materials for the loadbearing casings of explosionproof chambers) under shock compression and tension (spalling) at shockfront pressures of 1–5 GPa and strain rates of 10³ – 10⁴ sec^-1. A comparative analysis is performed of the obtained and available data on the dynamic yield point and spall strength of St. 3, St. 20, 09G2S, 12Kh18N10T, ÉI712, 30KhGSA, 36NKhTYu, KhVG, and 35Kh3NM steels and armco iron, whose strengths and ductilities under static loading conditions differ by a factor of up to five. Experiments are described in which spheres of St. 3, St. 20, 12Kh18N10T, and 30KhGSA steels with markedly different strengths and ductilities are loaded by a convergent quasispherical shock wave with a pressure at the center of 200 GPa and a strain rate of 10⁵sec^-1.     

人热休克蛋白70基因的克隆、表达及鉴定

目的克隆人热休克蛋白70(HSP70)基因,构建其原核高效表达载体。方法将PCR扩增的HSP70基因克隆到原核高效表达载体pET-28b中,转化大肠杆菌JM109。挑选阳性克隆,提取质粒pE28b70F,转化大肠杆菌BL21(DE3),IPTG诱导表达目标蛋白。结果在大肠杆菌中成功表达了HSP70,表达量约占细菌总蛋白的22·3%,其中可溶性目标蛋白占上清总蛋白的12%。Westernblot表明该目标蛋白具有与鼠抗人HSP70单抗特异结合的抗原活性。通过Ni2+-NTA亲和柱,从1L诱导产物中纯化出约1520mg重组蛋白,纯度在80%以上。结论已成功表达HSP70,为进一步研究其生物学功能和作用机制奠定了基础。     

基于跨文化适应理论的电影《推手》赏析

运用跨文化适应理论对李安编剧并导演的电影《推手》的主人公所经历的文化震荡和跨文化适应过程进行了分析和解读。同时,结合《推手》的创作背景,指出《推手》实为一部跨文化交际的生动教材,不仅深刻描写了跨文化适应过程中人们要经历的情感痛苦和迷茫,而且客观呈现了人们在跨文化适应过程中从深感疏离到渴望融合的心理过程,能为即将体验跨文化适应过程的人们提供情感和心理准备。     

“广岛——日本‘最具活力’的城市”中的文化冲击

从跨文化交际中的文化冲击理论出发,解读＂广岛——日本‘最具活力’的城市＂一文。分析该文作者,一位普通美国记者,在战后重建的广岛所经历的种种不解和困惑。并进一步分析日美两个民族在对待等级秩序和人人平等,自杀是消极还是积极等方面存在的差异。正是这些文化差异导致普通美国民众对日本文化的误读并产生排斥性情感。