Using Neural Network to Predict the Interfacial Friction and Flow Stress of Materialsvia Ring Compre

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中学教师焦虑情绪、心理压力和应对方式的比较研究

目的探究中学教师在焦虑情绪、心理压力、应对方式三方面的差异,以指导教师进行有效的情绪管理和压力应对。方法采用Zung焦虑自评量表、心理压力问卷、简易应对方式问卷对716名中学教师进行了问卷调查。结果（1）不同教龄的中学教师,市、县、乡中学教师在焦虑情绪、心理压力、积极应对或消极应对几个方面差异显著（P〈0．05）。（2）普通班与重点班的教师之间在焦虑情绪、心理压力上差异显著（P〈0．01）。结论教龄较长的中学教师,市、乡中学教师以及各中学重点班的教师焦虑情绪和心理压力较重;普通中学、城市中学的教师更多地采用消极应对模式。     

蜂窝纸板疲劳性能的研究

本文对蜂窝纸板疲劳性能进行了尝试性的试验研究,得到了蜂窝纸板的S-N曲线,同时了解了频率对蜂窝纸板疲劳寿命的影响,从而对蜂窝纸板包装运输方案的设计提供一定的依据。     

磁性液体密封机理的研究

根据悬浮液的分散团聚理论,提出了磁流变效应的机理,并推导出磁流变液屈服应力公式。根据磁流变流体的磁流变效应,推导出了磁性液体密封压力的计算公式,磁性液体的密封压力与磁性液体的屈服应力、密封结构的长度和间隙相关。采用狭缝式磁流变液流变性能测试系统,测试了现有磁性液体的屈服应力,对已有的磁流体密封装置进行了实验研究,该公式计算结果与实验结果吻合。     

MEMS薄膜平均应力梯度在线测量方法

结构层淀积是MEMS加工过程中的重要工艺步骤,淀积薄膜的应力梯度是影响MEMS器件性能的一个重要的力学参数．文中介绍了几种常见的平均应力梯度在线测量方法,阐明了其测试结构及测量原理,并对这些测量方法进行了比较．     

松针提取液抗疲劳作用研究

目的 :研究松针提取液的抗疲劳作用。方法 :将松针提取液分 3个剂量组 ,即 4 g/kg·d ,8g/kg·d ,12g/kg·d给小鼠灌胃 ,对照组为生理盐水。 2 0天后小鼠力竭游泳造成疲劳 ,测定超氧化物歧化酶 (SOD)、乳酸脱氢酶 (LDH)、血红蛋白 (Hb)、血乳酸 (LA)、血尿素氮 (BUN)等指标。结果 :8g/kg·d组为最佳用量 ,12g/kg·d组无明显优势 ;SOD和LDH的活性、Hb含量均有显著性升高 ,LA和BUN含量均有显著性降低。结论 :松针提取液具有抗疲劳作用而提高机体的运动能力。     

整理活动方式对消除运动员运动后血乳酸效果的分析

采用实验法，比较安静休息、轻松整理活动和专项整理活动方式对运动后血乳酸的清除、消除心理疲劳的效果。结果发现：积极性的整理活动效果明显优于安静休息；轻松整理活动和专项整理活动对血乳酸的清除效果无显著性差异，但轻松整理活动对消除心理疲劳的效果优于专项整理活动。     

The influence of an afternoon nap on the endurance performance of trained runners

The effectiveness of a nap as a recovery strategy for endurance exercise is unknown and therefore the present study investigated the effect of napping on endurance exercise performance. Eleven trained male runners completed this randomised crossover study. On two occasions, runners completed treadmill running for 30?min at 75% ?O_2max in the morning, returning that evening to run for 20?min at 60% ?O_2max, and then to exhaustion at 90% ?O_2max. On one trial, runners had an afternoon nap approximately 90?min before the evening exercise (NAP) whilst on the other, runners did not (CON). All runners napped (20?±?10?min), but time to exhaustion (TTE) was not improved in all runners (NAP 596?±?148?s vs. CON 589?±?216?s, P?=?.83). Runners that improved TTE after the nap slept less at night than those that did not improve TTE (night-time sleep 6.4?±?0.7?h vs. 7.5?±?0.4?h, P?r^{2 ?} =??0.76, P?=?.001). In runners that improved TTE, ratings of perceived exertion (RPE) were lower during the TTE on NAP than CON compared to runners that did not improve (?0.4?±?0.6 vs. 0?±?0, P?=?.05). Reduced exercising sense of effort (RPE) may account for the improved TTE after the nap. In conclusion, a short afternoon nap improves endurance performance in runners that obtain less than 7?h night-time sleep.     

Childhood trauma and neighborhood-level crime interact in predicting adult posttraumatic stress and major depression symptoms

Previous research has identified several individual-level factors that modify the risk of childhood trauma on adult psychiatric symptoms, including symptoms of major depression (MD) and posttraumatic stress (PTS). Neighborhood-level factors also influence the impact of individual-level exposures on adult psychopathology. However, no prior studies to our knowledge have explored cross-level interactions between childhood trauma and neighborhood-level factors on MD and PTS symptoms. The purpose of this study was therefore to explore cross-level interactions between a neighborhood-level factor – neighborhood-level crime – and childhood trauma on MD and PTS symptoms. Participants in this study (N = 3192) were recruited from a large public hospital, and completed self-report inventories of childhood trauma and MD and PTS symptoms. Participant addresses were mapped onto 2010 census tracts, and data on crime within each tract were collected. Multilevel models found a significant cross-level interaction between childhood trauma and neighborhood crime on MD symptoms, such that the influence of high levels of childhood trauma on MD symptoms was enhanced for participants living in high-crime neighborhoods. Supplementary analyses found variation in the strength of cross-level interaction terms by types of childhood trauma and crime, with the strongest associations including emotional neglect paired with personal and property crime. The results provide preliminary support for interventions that help childhood trauma survivors find housing in less vulnerable neighborhoods and build skills to cope with neighborhood crime.     

局部硬化区对焊接热影响区断裂萌生的影响

采用二维有限元数值方法分析了焊接热影响区粗晶区（ＣＧＨＡＺ）中局部硬化区（ＬＨＺ）的作用。当含有ＬＨＺ时，大大提高了ＬＨＺ内的应力并引起应变在ＬＨＺ和基体界面处产生不连续分布。ＬＨＺ的形状强烈影响ＬＨＺ内部的应力，在细长ＬＨＺ内几乎整体均呈现高应力分布，而块状ＬＨＺ仅在边缘区域出现应力集中。即使ＬＨＺ含量相同，随ＬＨＺ细长比的增大，ＬＨＺ内峰值应力及高应力区面积增加，说明细长ＬＨＺ容易在低应力水平下诱发断裂。这一结果在高强钢焊接热影响区ＣＴＯＤ试验中得到证实。含细长ＭＡ组元的ＣＧＨＡＺ在低得多的ＣＴＯＤ水平下发生断裂，因此控制ＭＡ组元的形状能够大大改善ＣＧＨＡＺ的韧性。