辐照损伤对锆合金电化学性能的影响

综述了堆内辐照对锆合金电化学性能影响的概况，浅析了堆内辐照损伤的机理，并重点探讨了主要的堆内辐照源——中子辐照对锆合金微观结构与氧化性能的影响。进一步阐述了堆外离子轰击模拟堆内中子辐照研究方法的进展概况，并就离子轰击实验参量的选择进行了较为深入的分析。     

Analysis of damage localization for ductile metal in process of shear band propagation

1 Introduction Shear localization is an important and often dominating deformation and failure mechanism for Ti and Ti alloy in dynamic loadings[1—10]. The eventual outcome of localized deformation is ductile rupture and material separation. Shear locali…     

2—甲基—1，4—萘醌对DNA光敏损伤的诱导作用

选择波长337nm的激光作为激励光源，借助凝胶电泳研究了2－甲基－1，4－萘醌诱导的DNA光敏损伤。结果表明：在氧气饱和、脱氧条件下光敏损伤显著，DNA损伤主要与光子剂量、核酸与萘醌浓度比及DNA存在形式有关。     

PBX炸药细观损伤的实验研究

为研究PBX炸药在冲击作用下的物理损伤、化学损伤及成热的物理机制,采用炸药爆炸驱动隔板实验技术对PBX炸药进行了冲击压缩实验,回收炸药试样并对其不同位置处的断面形貌进行SEM分析.结果表明,随着冲击能量的增加,其温度效应的影响越来越显著,损伤模式从物理损伤向化学损伤过渡.这为XDT问题中的"热点"形成机制等研究提供了实验基础.     

Measurement of Adhesive Bond Properties Including Damage by Dynamic Mechanical Thermal Analysis of a Beam Specimen

A method to obtain mechanical properties using a bonded (double) cantilever beam (or three point bend) specimen loaded in a manner to produce pure shear in the adhesive layer is reviewed. A revised mathematical solution which allows for easier interpretation of optimum beam dimensions to the one originally developed by Moussiaux, Cardon and Brinson for the static case is presented. An extension of this solution for a fixed/fixed viscoelastic beam under steady state oscillations developed by Li, Dickie and Morman is also discussed. Previous results using a vibrating beam to determine the complex viscoelastic properties of a bonded beam are reviewed. These results demonstrate conclusively that dynamic mechanical thermal analysis (DMTA) measurements discriminate differences in surface treatments and various environmental conditions. New measurements are presented that indicate the DMTA procedure can be used to quantify damage simulated by imbedded flaws in beams. The procedure is also shown to assess the effects of both humidity and corrosive environments on lap specimens. It is suggested that this technique may ultimately provide a method to quantify the amount of hidden damage in an adhesive joint subjected to fatigue, moisture or corrosive environments.     

大潮差河口闸下水流的流动特性分析

福建数座河口水闸发生剧烈淘刷,闸上游和下游的最大冲刷深度达到闸室高度的0.5~1.2倍,且屡修屡毁。有的水闸经多次除险加固后,不得不再花巨资重建。通过数学模型和物理模型揭示了河口水闸下游水位因受东海大潮差海潮影响发生剧烈波动时的变化规律,发现了水闸泄流过程中的间歇性淹没及非常工况甚至出现逆流的独特流动现象,给出了典型日孔流及堰流泄流能力动态变化过程线,分析了消能工变化对闸址水流结构的显著影响,并对水闸水毁修复前后闸下冲刷进行了预测。结果表明:水闸修复前闸下涨急最高水位4.53 m,修复后下降0.67 m,水闸修复后逆流现象减弱。修复后首次水跃位置往上游移动了35 m,平均水跃高度下降47.46%,闸后及二级池末端最大流速2.27 m/s和0.08 m/s,较修复前分别下降了40.58%和96.48%。常遇泄流条件下,水闸的淹没度和泄流能力呈现不断变化的动态过程。当西溪水闸62#先启孔全开,上游保持正常高水位3.2 m,下游为最低潮位-0.72 m时,修复后最大冲刷深度减少64.48%,消能防冲效果十分明显。研究成果对河口水闸安全运行具有一定的参考价值。     

混凝土冻融劣化后动态单轴抗压特性试验研究

为研究混凝土冻融循环后的动态力学性能,利用10 MN动静三轴仪对不同冻融劣化程度的混凝土在不同加载速率下进行单轴压缩试验,同时采集声发射数据分析试验过程中能量释放及损伤演化规律。最后,选用Weibull-Lognormal损伤本构模型,对试验数据进行拟合分析,并分析不同工况混凝土的损伤随应变的发展规律。研究结果表明:①相同冻融劣化程度时,随应变速率增加,峰值应力增大,峰值应变减小;冻融劣化程度会影响峰值应力的率敏感性;②在应变速率相同时,随冻融循环次数增加,峰值应力随之减小,峰值应变随之增大。③混凝土冻融劣化后应力应变关系峰前服从Weibull统计分布,峰后服从Lognormal统计分布。④在相同应变速率下,随着冻融循环次数的增加,混凝土的累计塑性应变整体呈增大趋势。     

JOB-9003炸药"激热"冲击损伤破坏及超声特征

进行了未经热处理的JOB-9003塑料粘结炸药(PBX)标准压缩试样的"激热"冲击损伤破坏试验,对试样热冲击试验前后的超声波特性参量进行了检测,试验显示出JOB-9003炸药存在一个明显的"激热"冲击损伤破坏临界温度差,并获得了试样热冲击损伤破坏的超声波参量特征.     

Raman spectra of virgin and damaged graphite edge planes

First-order Raman spectra of virgin and ion irradiated highly oriented pyrolytic graphite were performed along the basal and edge planes. Ion irradiation was performed in the low fluence regime (≈ 10¹²–10¹³ ions cm⁻²) using a 400 keV Ar⁺ beam in order to a introduce controlled amount of defects in the structure. Virgin edge Raman spectra reveal the presence of a 1351 cm⁻¹ structure (D^*) shifted 10 cm⁻¹ away from the disorder induced D-line found upon irradiating or grinding the graphite surface.The 1351 cm⁻¹ D^* structure is then considered as the feature coming from the rupture of the D_6h⁴ space group symmetry. A comparison between D^* and the classical 1360 cm⁻¹ D-line is discussed in terms of induced disorder.     

药物抗氧化作用对DNA发光动力学行为的影响

本文应用ＣｕＳＯ４－Ｐｈｅｎ－Ｖｃ－Ｈ２Ｏ２－ＤＮＡ化学发光体系观察药物对发光动力学行为的影响，研究了九种药物对ＤＮＡ损伤的保护作用，并对其药物结构对抗氧化能力的影响进行了分析。发现药物在该系统中的抗氧化作用有三种类型，提示它们可能在体内不同的反应过程中起不同的作用。在该系统中具有抑制ＤＮＡ损伤发光能力的药物，按其作用强弱依次为阿魏酸、丹参素、芦丁，茶多酚、ＳＯＤ、、丹参酮Ⅱ－Ａ，丹皮酚，五味子乙