A GEOGRAPHIC INFORMATION SYSTEM TOOL FOR AQUATIC RESOURCE CONSERVATION IN THE RED AND SABINE RIVER WATERSHEDS OF THE SOUTHEAST UNITED STATES

Our goal was to build a geographic information system (GIS) tool to enhance modeling and hypothesis testing relevant to watersheds and fish fauna of the Red and Sabine Rivers in the southeastern United States. Species of concern were identified from wildlife action plans and Web sites. Spatial distributions of fish species and mercury in fillets were delineated using data from states. Public georeferenced data were obtained on land cover, soil type, forest canopy, impervious surfaces, wastewater facilities and 303(d) impaired waters. Overlay maps highlighted patterns across 8‐digit hydrologic unit codes (HUCs). Bossier City, Louisiana and Beaumont, Texas areas displayed impervious surfaces over 10% and 303(d) waters per HUC were 20% and 8%, respectively. Because bowfin (Amia calva) (n = 299) and bass (Micropterus spp.) (n = 1493) occurred in up to 44% of HUCs and fillets contained elemental mercury concentrations across ranges monitored, they were appropriate indicators of bioavailable mercury. Of the total fish number showing >0.5 ppm, 81% of records were derived from bowfin and bass, and stepwise multiple linear regressions indicated fish with mercury at these concentrations correlated with environmental variables. Detrended correspondence analysis showed total species occurrence and environmental relationships significant, where 81.6% of the variability in fish occurrence was explained by impervious surface, land cover other than canopy or impervious surface (such as wetlands and agricultural area) and canopy (forest type). Two‐way indicator species analysis delineated species co‐occurrence in HUCs (14 groups) and similarity of species composition (nine groups). Results identified three HUC groupings as potential targets for managerial interest. Quality control concerns for GIS development included site name data and priority rankings of critical fish species. This tool can be used to support modeling and trend analyses for several purposes, such as those relevant for developing and reporting on water quality standards and critical habitat assessments. Published in 2011 by John Wiley & Sons, Ltd.     

高压水射流径向水平井钻井技术

介绍了高压水射流径向水平钻井技术的工作原理、系统构成、关键技术及国内外试验应用情况 ,并对目前国内试验中存在的问题进行了讨论。     

第二代超低电流电压检测器NCP302/NCP303系列ICs及应用

NCP302和NC303系列ICs是安森美公司生产的第二代超低电流并带有可编程延时的电压检测器。文中介绍了NCP302和NCP303系列器件的引脚排列、内部结构和主要特性，最后给出了该两系列电压检测器件的几种应用电路。     

CrossoverNet: A computer graphics/ video crossover LAN system

A new type of local area network operating system namedCrossover Net is developed for effective control of digital devices and audio visual devices such as video cameras, TV displays, video discs and video cassette recorders. A remarkable feature ofCrossoverNet is that it can handle and transfer both digital and analog information, including data, video and voice, in an integrated manner. To ensure secure operations of the entire network, we formalizeCrossoverNet in a precise mathematical way by defining object, job, task and process as data types belonging toCrossoverNet. We also present a practical installation example of theCrossoverNet system.     

不同检波方式对测试结果的影响

该文主要是想通过几个实际的案例来探讨不同的检波方式对测试结果是否会产生影响,特别是AV检波和CISPR AV检波在测试结果上到底有什么样的差异。     

矩阵变换器输出电压频谱的分析

矩阵变换器是采用高频PWM调制技术的交-交型电源变换器,其输出电压中包含的谐波分量会影响输出波形的质量。为此需要从理论上预估它的输出电压频谱特性并通过仿真数据验证理论分析,同时也为采取合适的PWM方法提高矩阵变换器输出电压谐波特性提供了依据。     

速冻水饺酸价和过氧化值的测定方法探讨

探讨了速冻水饺的酸价、过氧化值的测定值与浸泡时间和提取溶剂的关系。酸价的测定应在浸泡的8~18h内测定,过氧化值的测定有待于进一步研究,提取溶剂应使用石油醚。     

MPEG-7:音频视频信息的描述标准

从MPEG-7标准开发的目标、要求、MPEG-7标准的组成成分以及标准的应用领域四个方面阐述了MPEG-7标准的基本内容。     

基于UPnP的AV体系结构的设计与实现

UPnP是一种实现网络设备智能互连以及对设备服务自动控制的标准规范.介绍一种基于UPnP的AV体系结构,AV体系结构允许设备支持不同格式类型的娱乐内容(例如:MPEG4、JPEG、MP3、Windows Media Architecture(WMA)、bitmaps (BMP)、NTSC等)和多种传输协议(例如:IEC-61883/IEEE-1394、HTTP GET、RTP、HTTP PUT/POST、TCP/IP等).