多相感应电机任意非正弦气隙磁密的磁动势分析与应用

多相感应电机转矩密度的提高依赖于非正弦气隙磁密行波的合理构建,由于传统的电流相位、幅值控制策略无 法给出期望的非正弦磁密行波,因此文章研究了控制多相感应电机定子相电流中基波和谐波幅值、相位、频率的大小来 构建期望的气隙磁密波形的方法、首先基于单根载流导体产生的气隙磁动势波形,推导了任意相数、不对称、包含任意 高次谐波电流波形激励的具有典型绕组结构的多相感应电机的磁动势分布表达式。根据以上磁动势分析结论,多相电 机可通过变电流相序变极。针对气隙磁密行波逼近方波波形的案例,根据所提出的磁动势分析方法分析和预测了理想 空载励磁电流的波形。将预测波形和方波供电下的励磁电流波形进行了比较,从FFT分析结果来看,仍需微调各次谐波 电压相位,从而实现各次电流相位完全一致。     

扩大中间阶层是构建和谐社会的必要条件

中间阶层实质上是一个经济地位、政治地位和社会地位等各方面介于上层精英阶层和下层大众阶层之间的、具有中等社会经济地位的阶层和群体的集合.扩大中间阶层是构建和谐社会的必要条件.通过运用财政税收政策,大力发展教育和科技,鼓励创业,建立顺畅的社会流动机制等方式壮大我国的中间阶层对促进构建社会主义和谐社会有重要的作用.     

《红楼梦》中刘姥姥与《堂吉诃德》中桑丘形象对比

刘姥姥和桑丘是来自两个不同地域的人物,但是他们的行为方式和思想意识又有着许多的相似点,他们身上都体现出了农民的自私狭隘,同时也表现出了农民所固有的善良品性。透过他们,可以看到那个时代的黑暗面,看到不同阶层的生活状态和贫富差距,看到底层人民的悲惨命运和上层贵族的穷奢极欲。     

牛津高中英语教材本土文化调查分析

在文化教学渐渐引起国内外学者关注的时候,牛津版高中英语教材作为新一代教材的成功典范在文化导入方面已经给予重视,而在本土文化的导入中是否也达到了新课标的要求？笔者以牛津版高中英语教材九级水平为评测目标,以教材的9、10、11三个模块为研究对象,设计本调查力求回答上述问题,并指出该教材中存在的问题。     

论清初丁酉世盟高会

顺治十四年,冒襄于南京举行了丁酉世盟高会,大会故交同盟子弟.雅集上众人共同抒发了故国之思及抗清思变的愿望,造成集体拒绝参加江南乡试的政治影响.然而由于同盟后人的敌国之思终究存在隔闵、抗争思想不够坚决及难以抗拒现实利益的诱惑,使得拒绝参加清廷科考只能是暂时性的偶发事件.     

Longitudinal predictors of reading achievement among at-risk children

Early exposure to multiple risk factors is related to an elevated risk for academic difficulty. Thus, it is important to promote academic resilience as early as possible and to identify factors that support resilience. Given the positive relation between early literacy skills and later academic outcomes, examining resilience in reading is important. This study examined, first, whether the reading gap widens or narrows for below-average and above-average, at-risk children during the first four years of school; and, second, what protective factors predict reading achievement over time from kindergarten through the end of third grade. Results indicated that as a group, low-achieving children made smaller gains in reading than high-achieving children over the first four years of school. In addition, participation in center-based prekindergarten care, plus more access to books in the home, better interpersonal skills, and fewer poor physical conditions immediately surrounding elementary schools served as protective factors for at-risk children's early literacy development.     

联结主义理论与英语阅读教学

联结主义理论给英语教学新的启示。本文在理论分析的基础上,结合英语阅读教学的现状和个人教学实践,提出了阅读教学中应用联结主义的教学步骤。探讨了强化注意程度,激活输入的语言信息,提高输出意识的教学方法。     

代焦虑与创伤记忆--读君特·格拉斯的《狗年月》

《狗年月》是格拉斯的但泽三部曲之一部,这部作品与其他两部相比,作者的视野更加开阔.本文集中于分析小说中的"代现象",并以此为基点讨论德意志保守主义传统与纳粹统治的关系,揭示在高度分化的现代社会,不同群体之间的隔膜与争执,进而讨论如何承担历史责任的主题.     

Modeling the demand reduction input-output (I-O) inoperability due to terrorism of interconnected infrastructures.

Interdependency analysis in the context of this article is a process of assessing and managing risks inherent in a system of interconnected entities (e.g., infrastructures or industry sectors). Invoking the principles of input-output (I-O) and decomposition analysis, the article offers a framework for describing how terrorism-induced perturbations can propagate due to interconnectedness. Data published by the Bureau of Economic Analysis Division of the U.S. Department of Commerce is utilized to present applications to serve as test beds for the proposed framework. Specifically, a case study estimating the economic impact of airline demand perturbations to national-level U.S. sectors is made possible using I-O matrices. A ranking of the affected sectors according to their vulnerability to perturbations originating from a primary sector (e.g., air transportation) can serve as important input to risk management. For example, limited resources can be prioritized for the "top-n" sectors that are perceived to suffer the greatest economic losses due to terrorism. In addition, regional decomposition via location quotients enables the analysis of local-level terrorism events. The Regional I-O Multiplier System II (RIMS II) Division of the U.S. Department of Commerce is the agency responsible for releasing the regional multipliers for various geographical resolutions (economic areas, states, and counties). A regional-level case study demonstrates a process of estimating the economic impact of transportation-related scenarios on industry sectors within Economic Area 010 (the New York metropolitan region and vicinities).     

The Incremental Group Testing Model for Gap Closing in Sequencing Long Molecules

In this paper, we propose the incremental group testing model for the gap closing problem, which assumes that we can tell the difference between the outcome of testing a subset S, and the outcome of testing S {x}. We also give improvements over currently best results in literature for some other models.