减速齿轮传动中主动轮齿根弯曲疲劳的计算

传动齿轮强度理论认为,齿间滑动摩擦对齿轮齿根弯曲疲劳的影响可忽略不计。针对此说法,本文作者对带惰轮的起重减速齿轮传动中主动轮受国情况展开全面的分析研究,推导出包括齿间滑动摩擦力在内的,实际外载荷作用下的主动轮齿根弯曲疲劳应力计算公式。结果表明,齿间摩擦力对含惰轮的减速齿轮传动中主动轮齿根弯曲疲劳强度的影响不可忽视。     

How and for whom are decision aids effective? Long-term psychological outcome of a randomized controlled trial in women with newly diagnosed breast cancer.

Objective: The current study evaluates the long-term psychological impact of a decision aid intervention for surgical and systemic treatment in women with newly diagnosed breast cancer from a previous reported randomized, controlled trial (Vodermaier et al., 2009). Methods: Patients (n = 111) were randomized into usual care, or a 20-min decision aid intervention plus an information brochure prior to consultation planning with the senior physician. The retention rate at 1 year was 88%. Results: Linear mixed model analyses demonstrated that the intervention group experienced less decisional conflict (p = .047; d = .19), which was driven by perceptions of a more effective choice (p = .029; d = .20) over time. Subgroup analyses revealed that patients in the intervention group who participated in chemotherapy decision making showed better long-term body image outcomes (p = .009; d = .44), which were mediated by reduced depressive coping (p = .049). No effects emerged for anxiety and depressive symptoms, or for quality of life. Internal health locus of control moderated group effects on 'uncertainty with the decision' (p = .003). Conclusions: The study results provide novel evidence on the role of individual differences and the mechanisms behind decision aid effectiveness, and demonstrate the long-term impact of decision aid interventions on some indices of well-being. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The renewable energy consumption–growth nexus in Central America

This study examines the relationship between renewable energy consumption and economic growth for a panel of six Central American countries over the period 1980–2006. The heterogeneous panel cointegration test reveals a long-run equilibrium relationship between real GDP, renewable energy consumption, real gross fixed capital formation, and the labor force with the respective coefficients positive and statistically significant. The results from the panel error correction model indicate bidirectional causality between renewable energy consumption and economic growth in both the short- and long-run.     

Construct validity of the multidimensional structure of bullying and victimization: An application of exploratory structural equation modeling.

Existing research posits multiple dimensions of bullying and victimization but has not identified well-differentiated facets of these constructs that meet standards of good measurement: goodness of fit, measurement invariance, lack of differential item functioning, and well-differentiated factors that are not so highly correlated as to detract from their discriminant validity and substantive usefulness in school settings. Here we demonstrate exploratory structural equation modeling, an integration of confirmatory factor analysis and exploratory factor analysis. On the basis of responses to the 6-factor Adolescent Peer Relations Instrument (verbal, social, physical facets of bullying and victimization), we tested invariance of factor loadings, factor variances–covariances, item uniquenesses, item intercepts (a lack of differential item functioning), and latent means across gender, year in school, and time. Using a combination of relations with student characteristics and a multitrait–multimethod analysis, we showed that the 6 bully/victim factors have discriminant validity over time and in relation to gender, year in school, and relevant psychosocial correlates (e.g., depression, 11 components of academic and nonacademic self-concept, locus of control, attitudes toward bullies and victims). However, bullies and victims are similar in many ways, and longitudinal panel models of the positive correlations between bully and victim factors suggest reciprocal effects such that each is a cause and an effect of the other. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

一类二次奇摄动Robin问题

本文研究了可描述某伴随有体积变化的化学反应的一类二次奇摄动边值问题.在适当的条件下,先利用幂级数形式展开法,就退化问题的边值条件的一重根、二重根、三重根分别构造了问题的外部解.其次利用伸长变量,构造问题的内层解,并应用微分不等式理论,证明了边值问题解的存在性、一致有效性和渐近性态.     

掺假藕粉中木薯淀粉和甘薯淀粉的鉴别-差示扫描量热法

为了对掺入藕粉中的其他淀粉种类进行鉴别,本研究通过差示扫描量热仪对藕粉等常见几种淀粉的糊化过程进行考察发现,藕粉与其他淀粉在糊化吸热峰上有着明显的差别。根据藕粉与木薯淀粉和甘薯淀粉等在糊化吸热峰上的差异,以糊化吸热峰作为特征指标,对掺假藕粉中掺入的木薯淀粉和甘薯淀粉进行定性或定量鉴别实验。同理,此方法也可用于检验与藕粉在糊化吸热峰上有明显差异的用于藕粉掺假的其他淀粉种类,如马铃薯淀粉,玉米淀粉等。此方法将弥补前期发表的基于淀粉颗粒超微形貌特征的可食用淀粉种类扫描电镜鉴别方法的不足。     

On LM‐type tests for seasonal unit roots in the presence of a break in trend

This article proposes tests for seasonal unit roots allowing for the presence of a break in the trend slope occurring at an unknown date. In particular, new LM‐type tests are derived based on the framework introduced by Hylleberg et al. (1990). Null asymptotic distributions are derived for the no break case as well as when a break is present in the data‐generating process and a Monte Carlo investigation on the finite sample size and power performance of the new procedures is presented.     

Variation of local stress ratio and its effect on notch fatigue behavior of 2024-T4 aluminum alloy

Fatigue tests and finite element analysis of notched specimen were carried out to investigate the variation of local stress ratio at notch root and its influence on fatigue strength. The S–N curve of 2024-T4 aluminum alloy was kinked at the critical nominal stress amplitude, above which the local stress ratio became low due to the development of local plastic deformation at notch root. The predicted fatigue lives based on linear fracture mechanics approach were in agreement with the experimental results below the critical nominal stress amplitude. The predicted fatigue lives based on the SWT parameter, where the variation of local stress ratio was taken into account, were in good agreement with the experimental results above the critical nominal stress amplitude.     

GAMIT 基线解算质量指标分析

详细介绍GAMIT基线解算分步处理与自动化处理的质量评价指标,同时分别利用fortran语言和bash编写自动提取单天解标准化均方差和基线重复率自动计算的程序,实现快速评定基线解算结果质量的功能.     

基于根原因分析法的飞机连接器熔损故障分析

以连接器熔损故障事件为案例,应用根原因分析法进行失效分析,展示了其应用的整个过程,解释了根原因到达顶事件的路径及失效机理.通过完整记录所有收集的证据和调查中所采用的行动,极大地增加了确定导致顶事件发生的真正根原因的机会,并提供了不会导致顶事件发生而终止的解释.对导致顶事件发生的所有可能原因进行全面调查,提高了对调查过程的认识,并且可将所获得的技术应用于相关的设计中,防止同类事件再次发生.