电力电子和未来的航海电气系统(上)

明天的航海电气系统将同今天的系统有极大的不同。电力电子给予船舶上包括推进、电力分配、备用电源、声纳和雷达等在内的各种系统的进展以重要的影响。刚刚出现的新材料、新器件和新的系统概念(诸如宽带半导体材料、碳化硅基的电力半导体器件、电力电子模组(PEBB),以及集成功率系统)正在使、并将持续地使未来的航海系统有别于今天的系统,如同内燃船舶有别于蒸汽船舶。但是,这些正在实现的技术和有关概念还未被大家所周知,而且还有难于理解的地方。本文就将介绍这些新概念和新技术,指出潜在的影响力,并揭示新的设计方法,以推动航海电气系统的发展。     

TPS6211x电源供应设计的实际考虑

作者:Jeff Falin、Bill Johns·电源管理产品/便携式电源DC/DC应用TPS6211x dc/dc转换器是一种同步降压转换器,其输入电压最高可达17V,输出电压范围为1.2-16V,输出电流高达1.5A。该器件可以高效地将两节锂离子电池、铅酸蓄电池或12V-15V系统电压降至5V、3.3V或者更低。图1为典型应用电路。图1:典型应用本文将提供TPS62111x降压转换器的示例应用并对关键特性进行总结,以供实际设计参考。外部组件的尺寸要求集成FET及内部补偿功能可进一步减少外部组件教。假设不使用集成输出电压与输入电压监控电路,则固定输出电压(5V或3.3V)时仅…     

全湿法、无灰化的全新去胶技术

在集成电路（IC）制造中，需要多次重复去除掩模用光刻胶这一步骤，因此清洁、高效地去胶工艺非常重要。90nm高性能逻辑器件的制造过程使用超过30次光刻工艺。从晶圆表面去除光刻胶的能力在很大程度是由光刻胶性质和工艺历史决定的。在离子注入工艺中，图形化的光刻胶起掩模的作用，特别难以清除。大剂量的离子注入（〉1×l014ions／cm^2）将光刻胶表面脱氢并高度交联，其性能很像非晶碳。改性光刻胶的厚度由注入剂量、注入能量和注入离子种类决定。     

Maternally modulated infant separation responses are regulated by D2-family dopamine receptors.

Although dopamine is necessary for mammalian adult pair-bond formation and maternal behavior, its function in infant social behavior and attachment has been less thoroughly explored. The vocalization rate of an isolated rat pup is influenced by recent social contact. Interactions with the dam potentiate vocalization rate. Interactions with littermates or adult males do not. Systemic administration of the D2-family agonist quinpirole specifically blocked maternal potentiation at doses that did not alter vocalization rate in an isolation prior to dam contact. This result was not explained by quinpirole's effects on body temperature or locomotion. The results are consistent with a role for dopamine in infant social behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Nature of Struck-by Accidents

Construction accidents are broadly categorized into five basic groups, namely falls (from elevation), shock (electrical), caught in/between, struck-by, and other. “Struck-by” accidents accounted for 22% of all construction-related fatalities recorded by the Occupational Safety and Health Administration between 1985 and 1989. Recent (1997 to 2000) data show that the percentage of struck-by accidents constituted 24.6% of the fatalities and serious construction worker injuries. Struck-by accidents primarily involve workers struck by equipment, private vehicles, falling materials, vertically hoisted materials, horizontally transported materials, and trench cave ins. Determining possible causation factors of these accident types is often difficult, due to the broad categories utilized in the accident coding system. This study resulted in gaining insights about the root causes of the struck-by injuries. By finding the root causes, effective methods for accident prevention can be developed.     

Health Service Use Predictors Among Trauma Survivors: A Critical Review.

This article had 2 aims: (a) to comprehensively review and synthesize the literature on predictors of health service utilization in survivors of traumatic events and posttraumatic stress disorder (PTSD) patients and (b) to discuss methodological issues in examining service utilization in this population. PsycINFO was searched for relevant articles published through April 2004. Included studies had to primarily sample trauma survivors or PTSD patients and statistically explore health service use determinants. Although some findings conflicted across studies, increased mental health service use was generally related to being female, having a previous trauma history, and having a PTSD diagnosis. Increased medical service use was found among those with a PTSD diagnosis. Methodological recommendations are made for future health service use studies. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Development of a measure for the information technology infrastructure construct

The goal of this research was to operationalize the information technology infrastructure (ITI) concept by identifying its underlying dimensions and establishing a valid and reliable measure for the construct. In order to accomplish this task with the highest degree of certainty, two approaches were sequentially applied: exploratory factor analysis and confirmatory factor analysis. In evaluating the confirmatory factor model, a step-by-step process was employed, assessing unidimensionality, reliability, discriminant validity, and nomological validity. The dimensions of ITI were determined to be: Chief Information Officer, IT Planning, IT Security, Technology Integration, Advisory Committee, Enterprise Model, and Data Administration. Researchers may now make use of this validated ITI measure to conduct investigations of ITI and other organizational measures. Implications of the ITI measure with other organizational initiatives such as electronic commerce and knowledge management are explored.     

Determinants of the Relative Advantage of a Structured SDM During the Adoption Stage of Implementation

This research investigates a new theoretical model for examining the relationships between user perceptions during innovation adoption. We have taken several innovation-related variables and constructed a framework for assessing the ability of a technology to improve worker performance. Prior research has not addressed the appropriate relationship between innovation adoption-related variables as applied to information systems development methodologies (SDM). This study attempts to use innovation-related variables created by Moore and Benbasat (Information Systems Research 2(3) (1991) 192–222) and Davis (MIS Quarterly 13(3) (1989) 319–340) to propose a framework useful by project managers in designing innovations that will successfully support the efforts of technology users. A framework is proposed, tested, and modified in the context of using an SDM to govern large systems development operation. Forty-seven users within a military software development organization were surveyed about their perceptions of a recently implemented structured SDM. A proposed model of innovation adoption perceptions was tested using correlation and partial least squares regression. Findings suggest a model for predicting the perceived relative advantage of SDMs in the adoption stage of their implementation which is useful in designing techniques in the IS development organizational function.     

Open-Source Change Logs

A recent editorial in Empirical Software Engineering suggested that open-source software projects offer a great deal of data that can be used for experimentation. These data not only include source code, but also artifacts such as defect reports and update logs. A common type of update log that experimenters may wish to investigate is the ChangeLog, which lists changes and the reasons for which they were made. ChangeLog files are created to support the development of software rather than for the needs of researchers, so questions need to be asked about the limitations of using them to support research. This paper presents evidence that the ChangeLog files provided at three open-source web sites were incomplete. We examined at least three ChangeLog files for each of three different open-source software products, namely, GNUJSP, GCC-g++, and Jikes. We developed a method for counting changes that ensures that, as far as possible, each individual ChangeLog entry is treated as a single change. For each ChangeLog file, we compared the actual changes in the source code to the entries in the ChangeLog> file and discovered significant omissions. For example, using our change-counting method, only 35 of the 93 changes in version 1.11 of Jikes appear in the ChangeLog file—that is, over 62% of the changes were not recorded there. The percentage of omissions we found ranged from 3.7 to 78.6%. These are significant omissions that should be taken into account when using ChangeLog files for research. Before using ChangeLog files as a basis for research into the development and maintenance of open-source software, experimenters should carefully check for omissions and inaccuracies.     

The Relationship Between Witnessing Parental Conflict During Childhood and Later Psychological Adjustment Among University Students: Disentangling Confounding Risk Factors.

The purpose of the current study was to examine in detail the association between witnessing domestic violence (DV) and long-term psychological adjustment. Important limitations of past research were addressed, including controlling for several associated risk factors. Special attention was paid to whether the perpetrator of the violence was the maternal or paternal figure, as well as to whether the witness to the violence was male or female. Participants completed measures examining DV witnessed, direct child abuse experienced, and current psychopathology. Following screening for physical and sexual abuse, a sample of 351 individuals was selected. Four groups of participants were compared. Results indicated that individuals who had witnessed either physical DV or major psychological DV had higher levels of psychopathology than individuals who reported witnessing minor psychological DV or controls. After controlling for direct psychological abuse experienced, witnessing DV remained a significant predictor of psychopathology for males but not for females. (PsycINFO Database Record (c) 2010 APA, all rights reserved)