基于大气环境质量的电网绝缘污秽等级划分

通过测试户外挂网绝缘子表面自然积污量及实时监测湖南省各地市近年大气环境污染物主要因子(SO2,NO2,PM10)排放状况,建立了基于大气环境质量的输电线路绝缘子等值盐密、灰密的线性理论模型,并依据该模型对湖南电网绝缘污秽等级进行划分。结果表明,大气环境质量与绝缘子等值盐密、灰密之间具有较好的相关性,可通过对区域大气环境的实时监测,来实现对电网污秽等级的划分和动态调整。     

Severe and nonsevere events in first onsets versus recurrences of depression: Evidence for stress sensitization.

Overall, research has evidenced support for Post's (1992) model, which asserts that the 1st episode of depression is more likely to be associated with severe life events than are subsequent episodes. In spite of this, there are significant gaps in the understanding of the stress–depression association. This study aimed to address three gaps by (a) identifying the explanatory model underlying the association (stress sensitization vs. stress autonomy), (b) elucidating how the role of stress changes with successive episodes, and (c) examining the role of nonsevere events. The impact and occurrence of severe and nonsevere events in a 5-year longitudinal study of late-adolescent women were examined using Cox regression models. Overall, we found support for the stress sensitization model over the stress autonomy model. Specifically, the impact of nonsevere (but not severe) events was greater in individuals with a history of depression compared with those with no history of depression. In addition, the occurrence of severe (but not nonsevere) events was greater for 1st onsets than recurrences. These effects were modified by event independence. The results were discussed in terms of the underlying mechanisms of the stress–depression association and future directions for research were elaborated. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

新型污秽在线监测技术在防污管理工作中的应用

针对国内输变电设备外绝缘防污工作自动化水平较低状况,介绍了一种基于光传感器的污秽在线监测技术.分析了基于该技术和平台对超高压公司线路防污管理工作所带来的4种变化:新颖的污秽在线测量技术、高效的污秽管理工作平台、提供输变电设备外绝缘配置和设计的辅助决策功能.实践证明,采用新型污秽在线监测技术,可实现实时防污监测,提升工作...     

基于卡尔曼滤波的剩余寿命预测模型

振动烈度是剩余寿命的一个评价指标。为提高剩余寿命预测精度,解决时序模型预测延时问题,文中提出了一种时间序列分析理论,对振动烈度数据进行平稳建模,得到符合其变化规律的模型方程;通过得到的模型方程推导出卡尔曼滤波算法的状态方程和观测方程;然后依靠卡尔曼预测递推方程进行预测,再对振动烈度进行预测,从而预测剩余寿命。实例分析表明,采用混合算法可以提高预测精度,且较好地解决了预测延时问题。     

A latent class analysis of maternal depressive symptoms over 12 years and offspring adjustment in adolescence.

The authors used data from the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development to model patterns of maternal depressive symptoms, from the period of infants’ age 1 month to adolescence (age 12 years), and then examined adolescent adjustment at age 15 years as a function of the course and severity of maternal symptoms. The authors identified 5 latent classes of symptoms in 1,357 women, while also taking into account sociodemographic measures: never depressed, stable subclinical, early decreasing, moderately elevated, and chronic. Women with few symptoms were more likely to be married, better educated, and in better physical health than were women with more elevated symptoms. At age 15 years, adolescents whose mothers were in the chronic, elevated, and stable subclinical latent classes reported more internalizing and externalizing problems and acknowledged engaging in more risky behavior than did children of never depressed mothers. Latent class differences in self-reported loneliness and dysphoria were also found. Discussion focuses on adolescent adjustment, especially among offspring whose mothers reported stable symptoms of depression across their childhoods. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The impact fracture behavior of aluminum alloy 2024-T351: Influence of notch severity

In this paper, the interactive influences of notch severity and test temperature on the impact properties and fracture behavior of a Al-Cu-Mg alloy 2024 in the T351 microstructural condition is presented and discussed. Notch angles of 45, 60, 75, and 90° were chosen for a standard Charpy impact test specimen containing two notches. For a given angle of the notch, an increase in dynamic fracture toughness, with test temperature, is most significant for the least severe of the notches, i.e., 45°. At a given test temperature, the impact toughness decreased with an increase in notch severity. An increase in notch severity resulted in Mode I dominated failure at all test temperatures. The influence of localized mixed-mode loading is minimal for the alloy in the T351 microstructural condition. The impact fracture behavior of the alloy is rationalized in light of alloy microstructure, mechanisms governing fracture, and the deformation field ahead of the propagating crack.     

Predicting the impact of child sexual abuse on women: The role of abuse severity, parental support, and coping strategies.

Female Navy recruits (N=5,226) completed surveys assessing history of childhood sexual abuse (CSA), childhood strategies for coping with CSA, childhood parental support, and current psychological adjustment. Both CSA and parental support independently predicted later adjustment. In analyses examining whether CSA victims' functioning was associated with CSA severity (indexed by 5 variables), parental support (indexed by 3 variables), and coping (constructive, self-destructive, and avoidant), the negative coping variables were the strongest predictors. A structural equation model revealed that the effect of abuse severity on later functioning was partially mediated by coping strategies. However, contrary to predictions, the model revealed that childhood parental support had little direct or indirect impact on adult adjustment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Porteus maze performance following traumatic brain injury in children.

To investigate planning in traumatically brain injured children, the authors gave the Porteus Maze Test (PMT; S. D. Porteus, 1959) to 276 pediatric patients who had sustained a traumatic brain injury (TBI) at least 3 years previously. Sensitivity of the PMT to TBI severity, age at test, and volume of focal brain lesions detected by magnetic resonance imaging was also studied. The Peabody Picture Vocabulary Test-Revised (L. M. Dunn & L. M. Dunn, 1981) was also administered as a control measure. Results indicated that the PMT was highly sensitive to TBI severity and to volume of circumscribed prefrontal lesions. In contrast to the PMT data, receptive vocabulary was related to injury severity but not to discrete prefrontal lesions. Implications for mechanisms of cognitive deficit after TBI in children are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Factors influencing service utilization and mood symptom severity in children with mood disorders: Effects of multifamily psychoeducation groups (MFPGs).

This study investigated the impact of psychoeducation on service utilization and mood symptom severity in children with mood disorders. Parents’ knowledge of mood disorders, beliefs about treatment, and perceptions of children’s need for treatment were hypothesized to mediate the relationship between psychoeducation and service utilization and between psychoeducation and mood symptom severity. Linear mixed effects modeling and joint significance test for mediation were used in secondary data analyses of the multifamily psychoeducation group (MFPG) study, a randomized controlled trial of 165 children ages 8 to 12 years with mood disorders. A majority of those sampled were male (73%) and White, non-Hispanic (90%), and the median range of family income was $40,000–$59,000. Participation in MFPG significantly improved quality of services utilized, mediated by parents’ beliefs about treatment. Participation in MFPG also significantly improved severity of child’s mood symptoms, mediated by quality of services utilized. MFPG appears to be a psychoeducational intervention that helps parents to become better consumers of the mental health system who access higher quality services. Children’s symptom severity decreases as a result. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

风电典型机型的闪变严重度分析

风力发电机组的并网运行对当地电网的电能质量有不良影响。为此．根据定速机型、变速机型引起电压波动和闪变的原理及并网风电机组电能质量的国际电工标准IEC61400—21,讨论了测量风电机组输出闪变的方法,给出了两种典型机型的短时闪变严重度与风速的关系实验曲线,并对不同风速段的闪变成因进行了分析。结果表明,变速风电机组在高风速区域综合应用桨叶节距角和变流器控制实现输出功率的稳定能够减小短时闪变严重度,在低风速区域追求最佳风能利用系数将使闪变严重度值增高。