Simulation study of peak junction temperature and power limitationof AlGaAs/GaAs HBTs under pulsed and CW operation

The authors have used a 3-D transmission-line matrix (TLM) modeling method to study the junction temperature distribution and power limitation of device geometries with multiple embedded heat sources. Peak values of the junction temperature against the dissipated power density under both pulsed and CW operation are presented for a typical power AlGaAs/GaAs HBT structure. These data should facilitate the rapid determination of junction temperature for a given output power, which is of paramount importance in power device design     

Evaluation of constructed wetlands by wastewater purification ability and greenhouse gas emissions.

Domestic wastewater is a significant source of nitrogen and phosphorus, which cause lake eutrophication. Among the wastewater treatment technologies, constructed wetlands are a promising low-cost means of treating point and diffuse sources of domestic wastewater in rural areas. However, the sustainable operation of constructed wetland treatment systems depends upon a high rate conversion of organic and nitrogenous loading into their metabolic gaseous end products, such as N2O and CH4. In this study, we examined and compared the performance of three typical types of constructed wetlands: Free Water Surface (FWS), Subsurface Flow (SF) and Vertical Flow (VF) wetlands. Pollutant removal efficiency and N2O and CH4 emissions were assessed as measures of performance. We found that the pollutant removal rates and gas emissions measured in the wetlands exhibited clear seasonal changes, and these changes were closely associated with plant growth. VF wetlands exhibited stable removal of organic pollutants and NH3-N throughout the experiment regardless of season and showed great potential for CH4 adsorption. SF wetlands showed preferable T-N removal performance and a lower risk of greenhouse gas emissions than FWS wetlands. Soil oxidation reduction potential (ORP) analysis revealed that water flow structure and plant growth influenced constructed wetland oxygen transfer, and these variations resulted in seasonal changes of ORP distribution inside wetlands that were accompanied by fluctuations in pollutant removal and greenhouse gas emissions.     

三唑并嘧啶磺酰胺类除草剂的QSAR研究（II）

三唑并嘧啶类除草剂是作用于乙酰乳酸合成酶的新一类超高效除草剂，本文采用ＣＡＳＡＣ软件中的逐步线性回归方法，在二维水平上通过讨论三唑并嘧啶类化合物对油菜ｒａｐｅ（Ｇｏｓｓｙｐｉｕｍｓｐｐ．）欧龙牙草ｃｏｃｋｌｅｂｕｒ（Ｘａｎｔｈｉｕｍ，ｓｐｐ．）曼陀罗ｊｉｍｓｏｎｗｅｅｄ（Ｄａｔｕｒａ，ｓｔｒａｍｏｎｉｕｍ），牵牛花ａｎｎｕａｌｍｏｒｎｉｎｇｇｌｏｒｙ（ｌｐｏｍｏｅａｓｐｐ。）苋菜ｐｉｇｗｅｅｄ（Ａ     

湿法冶炼浸出过程H∞优化控制研究与设计

应用H∞优化控制方法对锌湿法冶炼浸出过程进行H∞优化控制器设计,同时,讨论了如何把浸出过程控制问题转化为H∞优化控制问题、浸出过程的输入输出量和H∞标准控制问题各量之间的关系及其物理意义.通过仿真实验,给出了几种情况下的仿真曲线,并进行了分析,从而得出结论.     

Land reclamation in the refuse dump of open coal mines and its following ecology principle

Through the research on the model of the land reclamation in the refuse dump of Heidaigou open coal mines, it was concerned that ecology was the theoretical basic for the land reclamation of open coal mines. According to the principle of ecological substituting, the land reclamation can be divided into three stages： water and soil conservation, ecological performance and economic performance. Taking the land reclamation in the refuse dump of Heidaigou open coal mines as the practical example, explained the application of the ecological substituting principle on the land reclamation in the open coal mines .     

短壁综放面快速推进矿山压力显现规律与特征

通过分析短壁综放工作面快速推进条件下的矿压显现规律与特征,为今后类似条件的工作面巷道布置、支护参数选择等提供切实可靠的依据。对工作面回采提出有针对性的防范措施,实现工作面快速推进时的安全生产。     

基于UMTS R4的多媒体彩铃方案

本文首先对UMTSR4网络进行了简要的概述,然后阐述了3种基于UMTSR4网络的多媒体彩铃方案,最后对这3种方案进行了比较。     

Research on relations between failure heights of overburden strata and ~] / mining face parameters and forecasting method

The commercial FEM software ANSYS was used to analyze the failure characteristics of overburden strata under the conditions of different lengths of mining faces. It was shown that the parameters of mining faces, especially the length was the important factor to the failure heights and shapes of overburden strata. Fuzzy mathematics and statistical methods were used to analyze the forecasting method of the failure height of overburden strata influenced by the parameters of mining face based on the measured data under the conditions of fully-mechanized mining of general hardness cover rocks. On the basis of these analyses, a new forecasting formula was gotten. The forecasting result conforms to the in situ measured value. The result has a very important application value in safe and high-efficient mining, and has a very important advancing function to theoretical studies.     

EPTPC:一种改进的两阶段分类算法

分类是数据挖掘中的重要任务之一。基本显露模式(eEPs)是一种有趣的知识模式,能够反映两个不同数据集之间的某些显著差异并减少分类噪音,适合解决针对稠密数据集和高维数据集的分类问题。但是,传统的采用顺序覆盖策略分类算法无法解决小覆盖问题和反例碎片问题。提出了一种改进的基于eEPs模式的两阶段分类算法,它将eEPs模式作为分类模式,采用两阶段思想来构造分类器,特别是优化了评分策略和两个阶段的权重设置。同时与NB,CBA,C5.0,CMAR,CAEP,BCEP等方法的分类结果进行了比较,在UCI机器学习库中的11个数据集上的实验结果表明了文中提出的算法的有效性。     

加大人才开发培养力度 积极创建学习型组织

人才开发培养历来是企业关注的核心问题。当代社会企业的竞争归根到底就体现在人才的竞争。通过创建学习型组织、开展各类型不同层面的培训学习,加强国内外科学和技术交流,建设网络虚拟学校和数字图书馆,举办读书会等多种途径,可以人才开发与培养方面创出一条新路。