Combination Effect of Dry-Ice Blasting and Substrate Preheating on Plasma-Sprayed CoNiCrAlY Splats

CoNiCrAlY splats were plasma-sprayed on the stainless steel substrate which was pretreated by dry-ice blasting. Only impact marks were distinguished on the glycerol-polluted substrate, while halo donut splats formed on the pretreated substrate because of the cleaning effect of dry-ice blasting on this organic substance. The proportions of different splat types vary as a function of the treatment time of dry-ice blasting. The condensation phenomenon was also detected on the substrate surface accompanying the cleaning effect after the pretreatment of dry-ice blasting. In this study, dry-ice blasting was investigated to be coupled with substrate preheating to control the substrate temperature. It was found that a regular disk-like CoNiCrAlY splat can be obtained as the substrate temperature is higher than dew point temperature.     

Neural Computation to Estimate Heat Flux in an Atmospheric Plasma Spray Process

Temperature is a key parameter in the thermal spray process and is a consequence of the heat flux experienced by the workpiece. This paper deals with the estimation of the heat flux transmitted to a workpiece from an atmospheric plasma spray torch during the preheating process often implemented in thermal spraying. An inverse heat conduction problem solution using a conjugate gradient method was considered to determine the heat flux starting from a known temperature distribution. Results from the later method were used to train an artificial neural network to discover correlations between selected processing parameters and heat flux.     

储油洞库油气爆炸燃烧建模与数值分析

以储油洞库油气爆炸为研究对象,分析洞库油气爆炸燃烧的特点,建立了基于湍流燃烧模型的油库油气爆炸燃烧分析模型。通过仿真模拟分析,对洞库内油气爆炸燃烧的特性进行了分析,验证了模型的实效性。从而为分析储油洞库油气爆炸燃烧的特点,进行下一步更深入的研究,确保洞库安全提出了一条有效的解决途径。     

电磁式剩余电流动作保护器可靠性(气候试验)的试验与研究

从一次电磁式剩余电流动作保护器(RCD)的可靠性试验失败案例开始,通过对比试验和对产品工作机理的分析,找到引起试验失败的根本原因。制订不同的改善方案,制作试品,通过试验逐一验证,最终确认最优方案。并按最佳方案批量生产试品,进行型式试验,最终确认改善方案成功。     

基于蚂蚁算法的断裂追踪技术在乌夏地区的应用

断裂解释是地震资料解释的重要内容,解释的可靠性对储层研究有很大影响。在乌夏地区地震资料进行预处理并综合应用相干体、方差体等技术手段检测地震反射不连续性的基础上,应用蚂蚁追踪技术进行断裂系统解释,对蚂蚁追踪属性体提取过程中涉及的6个参数的合理取值进行对照试验,并用地震、岩心、成像测井等资料对试验结果进行多次验证。文中利用构造平滑、方差计算增强断裂边界,通过参数试验,确定属性提取最优参数组合,并由产状控制滤除低角度层位痕迹,进而生成蚂蚁追踪属性体;对属性体提取积分厚度,预测平面裂缝发育情况,通过碎片拾取,确定裂缝大致方位及角度,以加深对乌夏地区二叠系风城组断裂系统的认识。应用分析表明,蚂蚁追踪的属性体断裂痕迹比相干体、方差体更为清晰,并能在平面及剖面解释上体现更多的细节。     

电成像测井在东濮凹陷裂缝性砂岩储层评价中的应用

为有效识别和精确评价以"双孔介质"为特征的东濮凹陷三叠系致密砂岩裂缝性储层,通过对电成像测井资料的地质应用研究,完善了其在裂缝定性识别与定量评价、地层产状描述、井旁构造分析、地应力分析及岩性识别方面的应用。用岩心刻度电成像测井(EMI)、再用电成像测井刻度常规测井,在地质条件及测试资料的约束下,总结出三叠系砂岩裂缝性储层的测井响应特征,进而形成了一套划分裂缝性储层的有效方法。据已测试的10口井分析,该评价方法的测井解释符合率达84.3%,提高了测井对三叠系裂缝性储层的识别能力。     

Effect of in-flight particle characteristics on the coating properties of atmospheric plasma-sprayed 8 mol% Y2O3-ZrO2 electrolyte coating studying by artificial neural networks

In-flight particle characteristics (surface temperature and velocity upon impact) are among the most important parameters which influence the coating microstructures and properties in atmospheric plasma spraying (APS) process. The purpose of this paper is to study hydrogen fraction used as secondary plasma forming gas on the in-flight particle surface temperature and by extension on the coating microstructures of atmospheric plasma-sprayed 8 mol% yttria stabilized zirconia electrolyte coatings implementing in particular artificial neural networks (ANN). Then, the predicted in-flight particle characteristics were on the one hand compared to experimental values and on the other hand correlated to some of the coating structural attributes (porosity and gas specific permeability). The predicted results were in good accordance with the experimental data. Results showed that the H₂ flow rate had obvious influence on particle temperature and had almost no significant effect on particle velocity. Increasing the particle temperatures induced dense coating microstructure and improved the gas-tightness performance.     

Modeling Aspects of High Velocity Impact of Particles in Cold Spraying by Explicit Finite Element Analysis

In this study, an examination of cold spray particle impacting behavior using the ABAQUS/Explicit program was conducted for typical copper material (OFHC). Various combinations of calculation settings concerning element type, Arbitrary Lagrangian Eulerian adaptive meshing, contact interaction, material damage, etc., were examined with the main focus on the element excessive distortion and its effect on the resultant output. The effect of meshing size on the impact behavior was also clarified compared to the previous results obtained by using the LS-DYNA code. Some fundamental aspects on modeling of cold spray particle deformation are discussed.     

基于局部结构张量的红外图像背景抑制

文中将局部结构张量与双边滤波相结合,提出了一种基于局部结构张量的红外图像结构化背景抑制算法。该算法采用局部结构张量的标准差作为双边滤波的执行判定,并利用双边滤波加权系数实现背景估计,从而实现结构化背景抑制和目标信息增强。实验结果显示,与二维最小均方滤波和偏微分方程算法相比,该算法对含有弱小目标的复杂背景具有良好抑制效果。     

超声后RADA16-I短肽纳米纤维支架重组装及成胶的研究

RADA16-I自组装短肽水溶液中形成纳米纤维并在盐离子作用下触发成水凝胶.RADA16-I纤维被大功率超声打断为小的原纤维片段.用AFM、CD和流变仪研究超声后纤维的重组装及其成胶性质.实验发现,超声未破坏纳米纤维二级结构,纤维仍保持β-sheet构型,超声4h后,小片段重组装为500nm的纤维,纤维虽未恢复到原长度,但仍未丧失其触发成胶的能力,只是在相同触发时间内达不到超声前的储能模量G′.还研究了超声对纳米纤维和成胶性能的影响,并提出相应的分子模型,这有助于短肽生物材料的应用,并对淀粉样蛋白病变的机理有一定的启示作用.