Effect of shot peening on hydrogen embrittlement of high strength steel

The effect of shot peening (SP) on hydrogen embrittlement of high strength steel was investigated by electrochemical hydrogen charging, slow strain rate tensile tests, and hydrogen permeation tests. Microstructure observation, microhardness, and X-ray diffraction residual stress studies were also conducted on the steel. The results show that the shot peening specimens exhibit a higher resistance to hydrogen embrittlement in comparison with the no shot peening (NSP) specimens under the same hydrogen-charging current density. In addition, SP treatment sharply decreases the apparent hydrogen diffusivity and increases the subsurface hydrogen concentration. These findings are attributed to the changes in microstructure and compressive residual stress in the surface layer by SP. Scanning electron microscope fractographs reveal that the fracture surface of the NSP specimen exhibits the intergranular and quasi-cleavage mixed fracture modes, whereas the SP specimen shows only the quasi-cleavage fractures under the same hydrogen charging conditions, implying that the SP treatment delays the onset of intergranular fracture.     

Thermodynamic simulation of the effect of slag chemistry on the corrosion behavior of alumina–chromia refractory

The corrosion behavior of alumina–chromia refractory against two kinds of industrial slags (coal slag and iron smelting slag) at 1550°C was investigated via thermodynamic simulations. In the proposed simulation model, the initial slag first attacks the matrix and surface aggregates and subsequently attacks the inner aggregates. The simulation results indicate that the slag chemistry strongly affects the phase formation and corrosion behavior of the refractory brick. Greater amounts of alumina were dissolved and spinel solid phases formed when the brick interacted with iron smelting slag. These phenomena, as well as the calculated lower viscosity, may lead to much deeper penetration than that exhibited by coal slag and to more severe corrosion compared to that induced by coal slag. The thermodynamic calculations well match the experimental observations, demonstrating the efficiency of the proposed simulation model for evaluating the corrosion behavior of alumina–chromia refractory.     

显著边缘直接引导的动态模糊图像盲复原方法

针对主动视觉中运动载体和云台抖动导致图像模糊的问题,提出一种显著边缘直接引导的动态模糊图像盲复原方法。为了克服经典 Canny 算子只能对边缘进行标注的缺陷,设计了图像边缘搜索-增强算法,并基于此提出了仅依据图像中显著边缘邻域完成点扩散函数优化估计的方法;为解决传统残差图像方法不能适应预测图像错位的问题,提出图像解模糊的递归残差修正算法来抑制复原图像波动;设计了图像复原的分层迭代处理流程,保证模糊图像复原的可靠性和精度。理想光照条件下的仿真表明,算法能准确恢复模糊图像的边缘,同时抑制复原图像中的波动。非理想光照条件下的仿真也验证了算法对环境有良好的适应性,具有较高的实际应用价值。     

冲喷嘴碰撞壁形状对射流特性影响的实验研究

本文根据现场使用的脉冲喷嘴碰撞壁形状的变化规律,将其划为七种典型的形状,测试并分析了碰撞壁形状交化对脉冲射流特性的影响规律,同时还将普通喷嘴与七种典型形状碰撞壁的脉冲喷嘴,在相同条件下进行了岩样冲蚀实脸.得到了很有意义的结论,这为评价脉冲喷嘴在现场的使用寿命,提供了可靠的依据。     

组合拱式管桥单项可靠指标的建立

本文探讨了组合拱式管桥载荷效应组合和结构构件抗力统计分析问题,建立了组合拱式管桥结构构件的失效准则,运用一次二阶矩中心点法推导出相应单项可靠指标的计算公式,这些公式可作为组合拱式管桥可靠性分析与设计的参考。     

确定抽油杆疲劳断裂常数的一种实用统计方法

针对疲劳裂纹扩展性能的统计性质,提出了一种确定抽油杆疾劳断裂材料常数的实用方法,该方法确定出的常数位与存活率相对应,与其它方法的结论基本一致。对抽油杆疲劳裂纹扩展寿命的分布和常数c与m之问的关系作了初步脸证。     

Riccatti微分方程的亚纯解

本文研究Riccatti微分方程u′一A(z)+u~2的亚纯解。得到该方程具有亚纯解(一个参数族亚纯解)的充要条件:存在一个非常数亚纯函数g(z),使i) g(z)的所有极点是奇数阶的:ii) g′(z)的所有零点是偶数阶的;iii)A(z)=1/2{g,z}     

贵州树木新分类群及新分布(续)

<正>长柄核果木 新种(图1) Drypetis longipes X. H. Song, sp, nov. Species foliis intergris, pedicellis fructuum 3～4cm. longis instractis. Arbuscula sempervirens, 8 m. alta, tranco 14 cm diam., cortice cineracei, levi,tenuiramis cernuis cinereis vel flavidi-inereis, lenticellis suberosis leviter elevatis,ramulis hornotinis interdum pubescentibus, deinde glabris. Folia alterna tenuicoriacea vel crassi-chartacea, elliptica vel ovato-elliptica, 7～10cm. longa et 3～4cm. lata, apice acuminata vel brevicaudata, acumine obtusis, basi cuneata, obliqua,utringque glabra, nitide, costa media supra elevata vel plana subtus elevata, nervis alteralibus utrinsecus 7～8(～9), curvis, prope marginem consutis, nervulis,subparallelis, subtus elevatis, manifestis, petiolis 3～5mm. longis, purpureis interdum pubescentibus. Fructus juvenes plerumque singulares, globosis viridis,dense brevipubescentis, stylis brevissimis 2-lobatis, persistentibus, stigmatibus latissimis, reniformibus, pedicellis 3～4cm. longis.     

中国灰鹤种群数量与年龄结构探讨

截至１９９５年,灰鹤在中国和总数量估计为１９３７２－２２３１１只,其种群的年龄结构：成鸟４４．１９％,亚成鸟３６．１％,幼鸟１６．８６％。总体属稳定增长型种群,其中,在我国东北和东部区域,成鸟８４．１６％,亚成鸟０．３４．５,幼鸟１５．５％左右,潜在着数量下降和年龄老化的危机,可能属下降种群;在我国云贵高原,成鸟３８．４８％,亚成鸟４１．２％,幼鸟１８．７２％,属潜在强劲发展态的增长型种群。     

不同葡萄糖浓度对霉菌产油能力的影响

为了筛选出高产油菌株,本实验采用细胞形态学与细胞化学方法(苏丹黑染色法)对常现青霉P1、土壤青霉P3、绿色木霉L1、红色脉孢霉H1四株霉菌进行跟踪观察,通过在不同葡萄糖浓度梯度的发酵液中摇瓶培养,并分析菌种生物量、葡萄糖利用率和油脂含量,从而确定最经济有效的葡萄糖浓度。结果表明,高浓度的葡萄糖会抑制霉菌油脂的合成,L1菌株在培养基中初始葡萄糖浓度为4%时,积累生物量、葡萄糖转化率均较大,油脂产量最佳为2.598g/L,菌体油含量达到38.62%(细胞干重)。