高水头泄水建筑物侧墙掺气减蚀特性研究

工程中通常采用强迫掺气减蚀措施,防止泄水建筑物在高速水流作用下发生空蚀破坏,但在保护过流面底板的同时,忽视了对其侧墙的保护。为了减免位于高流速区域和低压区域侧墙发生空化空蚀,消除侧墙清水区,采用理论分析和物理模型试验研究方法,对龙抬头明流泄洪洞下游边墙掺气减蚀进行了研究,提出了在反弧末端加折流器（突扩）和突跌掺气方式。结果表明,采用突扩和突跌的掺气方式后,侧墙水流的出射角增大,侧空腔畅通,并直接和底空腔相连,有助于掺气坎后水舌的全断面的掺气,对侧墙和底板皆起到了很好的保护作用。     

桥梁健康监测中损伤特征提取的小波包方法

针对桥梁健康监测中结构损伤识别的特点,从模式识别的角度提出和分析了损伤特征提取问题.阐述了基于小波包分析的两种节点能量特征提取的方法.为了研究小波包系数节点能量和小波包信号成分节点能量对损伤信息进行特征提取的差异,通过对随机荷载激励下的连续梁进行数值模拟,得到了结构未损和损伤状态下的加速度时程信号.应用小波包变换,对不同结构状态下的加速度信号分别提取了两种小波包节点能量特征,并对它们作为结构损伤特征指标的敏感性进行了比较.认为两种特征指标的敏感性相差很小,而小波包系数节点能量特征指标的计算效率更高,更适合桥梁健康监测中损伤特征提取的要求.     

超高性能混凝土(UHPC)在桥面板体系中的应用2020年度研究进展

超高性能混凝土（UHPC）与正交异性钢桥面板的组合是近年来桥梁工程中新材料、新构造研究的典型范例。UHPC桥面板的刚度较大,可以有效减小桥面板中的局部变形,从而明显降低正交异性钢桥面板中的疲劳应力幅,改善其抗疲劳性能。从新构造、剪力连接件性能、组合桥面板基本力学性能、组合桥面板疲劳性能及UHPC材料与构件力学性能等几个方面对UHPC-正交异性钢桥面板组合体系的研究进展进行综述,其内容主要为2020年以来发表的工作,部分兼及更早的研究成果。     

Role of TRPA1 in Tissue Damage and Kidney Disease

TRPA1, a nonselective cation channel, is expressed in sensory afferent that innervates peripheral targets. Neuronal TRPA1 can promote tissue repair, remove harmful stimuli and induce protective responses via the release of neuropeptides after the activation of the channel by chemical, exogenous, or endogenous irritants in the injured tissue. However, chronic inflammation after repeated noxious stimuli may result in the development of several diseases. In addition to sensory neurons, TRPA1, activated by inflammatory agents from some non-neuronal cells in the injured area or disease, might promote or protect disease progression. Therefore, TRPA1 works as a molecular sentinel of tissue damage or as an inflammation gatekeeper. Most kidney damage cases are associated with inflammation. In this review, we summarised the role of TRPA1 in neurogenic or non-neurogenic inflammation and in kidney disease, especially the non-neuronal TRPA1. In in vivo animal studies, TRPA1 prevented sepsis-induced or Ang-II-induced and ischemia-reperfusion renal injury by maintaining mitochondrial haemostasis or via the downregulation of macrophage-mediated inflammation, respectively. Renal tubular epithelial TRPA1 acts as an oxidative stress sensor to mediate hypoxia–reoxygenation injury in vitro and ischaemia–reperfusion-induced kidney injury in vivo through MAPKs/NF-kB signalling. Acute kidney injury (AKI) patients with high renal tubular TRPA1 expression had low complete renal function recovery. In renal disease, TPRA1 plays different roles in different cell types accordingly. These findings depict the important role of TRPA1 and warrant further investigation.     

基于RHT模型双孔同时爆破均质岩体损伤的数值模拟

为探究双孔爆破时炮孔间距和额外自由面对爆破过程中爆破损伤的影响,基于RHT（Riedel-Hiermaier-Thoma）损伤本构建立了多组三维数值模型,利用模型损伤云图研究不同爆破条件下的岩石爆破过程,通过自定义变量—有效损伤率的变化探究炮孔周围岩石损伤的时空演化过程。结果表明：随着炮孔间距的增加,岩石有效损伤率逐渐递减,相同截面处的有效损伤率在炮孔间距最小的方案中最大,相邻炮孔间的爆破能量叠加作用随炮孔间距的增大而减弱,合适的炮孔间距可以获得更加理想的爆破效果;岩石有效损伤率随着自由面到炮孔中心处距离的增大而逐渐减小,爆破能量倾向于向自由面方向传播,额外自由面对爆破能量分布的影响随自由面与炮孔间距的增大而减弱。数值模拟结果对研究双孔爆破能量的传递法则具有一定的借鉴意义。     

空间高能质子对飞行器材料的损伤分析

针对高能粒子在空间环境中的辐射,本文简要介绍了空间高能质子在空间环境中的分布情况及在物质中的传输问题,评述了国外有关高能质子的非电离能损失及线性能量转移研究,并在此基础上重点分析和研究了高能质子对航空、航天材料的辐射损伤.从空间高能质子对材料的辐射损伤的角度,分析讨论了材料厚度与屏蔽效果的关系并提出了一些相关性的结论和展望;能量为10MeV～80MeV的质子最可能发生辐射损伤效应,质子拟合公式适合于入射质子能量较小的情况.     

高纯Fe中氢损伤规律的研究

本文采用正电子湮没技术研究了高纯Fe中的氢损伤规律,实验结果表明,在0.5mol/L H_2SO_4溶液中不加毒化剂电解充氢时,产生氢损伤的临界电流密度为20 mA/cm~2;而在0.5mol/L H_2SO_4溶液中加少量As_2O_3作为毒化剂电解充氢时,即使很小的电流密度也会产生氢损伤,配合慢拉伸试验,还发现试样内部产生氢损伤以后,它将控制随后的形变和断裂过程     

Grain-size effects in the quasi-static fracture resistance of a thermally embrittled RPV steel (quenched and tempered microstructures)

The elastic-plastic fracture toughness and crack extension behavior under the quasi-static loading regimen of several thermally embrittled conditions of a nuclear reactor pressure vessel (RPV) steel were assessed on the basis of microstructural parameters. It was discovered that the bainite packet size is the fracture properties controlling parameter of single-phase quenched and tempered microstructures. Results were found in close agreement to those obtained in a parallel study with dual-phase annealed microstructures derived from the same low alloy steel. Similarly, it was concluded that a Hall-Petch type relationship correlates J-fracture mechanics criteria to the grain size.     

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…