基于无线通信的静止式进相器系统设计

静止式进相器是专为大中型绕线式电机节能降耗设计的无功功率就地补偿装置。现有静止式进相器仅停留在单台电动机和单台静止式进相器的配套使用上,缺乏监控系统、历史数据无法保存。详细介绍了基于无线通信的静止式进相器系统设计,系统由静止式进相器控制子系统和主控子系统组成,使用无线通信模块实现静止式进相器和主控机的通信。主控子系统设计中,采用预约ALOHA实现主控子系统的多址通信。该系统经过实验和现场调试,其结果表明:静止式进相器补偿效果明显,实现系统无线通信功能,满足无线监测的设计要求。     

圆周上的范德瓦尔登数

The big upper bound of typical van der Waerden number was investigated through calculating the van der Waerden number on a circle. And the van der Waerden number Wh (3,3) = 9, Wh (3,3,3)≥25 on a circle was calculated by computer.     

Does maternal employment influence poor children’s social development?

Various initiatives over the past 40 years have aimed to strengthen children’s early learning and social development. One policy theory—manifest in recent welfare reforms—postulates that requiring single mothers to work more outside the home will advance children’s well-being. We first examine whether young children’s social development is related to maternal employment among 405 women who entered welfare-to-work programs in 1998. For girls, age 24–42 months, we found that their mother’s recent employment duration was significantly associated with a lower incidence of aggressive behavior and inattentiveness, measured by two scales from the Child Behavior Checklist (CBCL 2/3). Yet these relationships with employment were weaker than more robust associations observed for proximal child-rearing practices, including the frequency of reading with the child, enforcing a regular bedtime, the propensity to spank the child, as well as levels of maternal depression. We then assess whether broader measures of the mother’s economic security help to predict these proximal determinants of development. We observed that food security and indicators of job quality consistently predicted the proximal factors. Structural equation models (SEM) provided additional evidence that these broader indicators of economic security, but not recent employment per se, operated through parenting practices and maternal depression to influence girls’ and boys’ social development. These results are consistent with recent findings from random-assignment experiments, showing that employment gains rarely affect child outcomes unless mothers’ income and broader economic security also improve.     

浅议高校共青团学生干部队伍建设

本文论述了高等学校共青团学生干部队伍的重要性，并对如何进行高校共青团干部队伍建设进行了有益的探讨。     

鄂州市莲花山地质特征

莲花山地处淮阳山字型前弧西翼,地壳组成主要是强烈钠长石化的中细粒闪长岩和斑状斜长花岗岩。由一系列断裂、节理(或劈理)组成、以格状构造为特征的现存构造格局显然是新华夏系构造迭加而造成的,力学结构面性质、特征显示它们形成于岩体冷却之后的脆性剪切应力作用。     

Relative efficiency of R&D activities: A cross-country study accounting for environmental factors in the DEA approach

This paper applies the production framework associated with the data envelopment analysis (DEA) method to evaluate the relative efficiency of R&D activities across countries. R&D capital stocks and manpower are treated as inputs while patents and academic publications are considered as outputs. A three-stage approach, which involves using DEA for evaluating efficiency and using Tobit regressions for controlling the external environment, is applied to 30 countries in recent years. The results show that less than one-half of the countries are fully efficient in R&D activities and that more than two-thirds are at the stage of increasing returns to scale. Most countries have a more significant advantage in producing SCI cum EI publications than in generating patents.     

网络经济下的网络游戏与动漫产业合作分析

前言在我国,游戏和动漫是数字内容产业中的朝阳产业。在欧、美、韩、日等国家、游戏与动漫产业已是其文化产业支柱之一。中国加入世界贸易组织之后,文化产业也将向世界开放,我们将不得不面对海外文化势力,尤其是产业规模、商业运     

支持手机检索的技术方案

随着手机的日益普及，人们越来越希望能利用手机从Internet获取各种信息，本文介绍了满足这一需要的两种技术方案。     

小型空心砌块建筑墙体裂缝的控制与防治

小型空心砌块建筑墙体设计到位,并在施工中应严格按有关规范和设计要求进行,裂缝是完全可以控制和防治的。