检索结果-南通市图书馆

卫星遥感影像在村镇及作物分布调查中的应用研究

在线全文

学校读者我要写书评

暂无评论

水土保持学报 2004年第1期18卷 130-133,137页

作者：许迪刘钰蔡林根 Vincent B 国家节水灌溉北京工程技术研究中心北京100044 法国农业及环境工程研究院

利用监督分类、经验指数、屏幕数字化等遥感影像处理方法,在山东簸箕李灌区开展村镇及作物分布调查的应用研究。在对采用卫星遥感影像(SPOT、LANDSAT)识别的村镇可视化效果进行对比的基础上,基于LANDSAT5影像,经屏幕数字化处理得到村镇... 详细信息

利用监督分类、经验指数、屏幕数字化等遥感影像处理方法,在山东簸箕李灌区开展村镇及作物分布调查的应用研究。在对采用卫星遥感影像(SPOT、LANDSAT)识别的村镇可视化效果进行对比的基础上,基于LANDSAT5影像,经屏幕数字化处理得到村镇分布现状,并依据NDVI指数推断作物分布状况。研究结果表明,

关键词：卫星遥感影像村镇作物分布经验指数屏幕数字化

Sequential Color LED Back-Light Driving System for LCD Panels

在线全文

学校读者我要写书评

暂无评论

Sequential Color LED Back-Light Driving System for LCD Panel...

CES/IEEE 5th International Power Electronics and Motion Control Conference

作者： C.-C. Chen C.-Y. Wu P.-C. Lu Y.-M. Chen and T.-F. Wu Elegant Power Application research center (EPARC) Department of Electrical engineering national Chung Cheng university Ming-Hsiung Chia-Yi Taiwan china Department of Electrical engineering Nan-Jeon Institute of Technology Yen-Shui Tainan Taiwan china

＜正＞In this paper, a sequential color light emitting diode （LED） backlight driving system for liquid crystal display （LCD） panels is proposed. Due to improvement on luminous efficacy, long life and wide color gamut, LED has gradually substituted for cold cathode fluorescent lamp as backlight. The proposed driving system adopts sequential color scanning scheme to improve light utilization efficiency by removing color filter. To meet display performance requirement where color variation uv needs to be limited below 0.002, this paper also proposes a family of output current ripple free topologies to reduce color variation caused by ripple current. In addition, a driving voltage reseter is introduced to resolve current-spike problem, improving backlight reliability and availability. A forward-type current ripple free converter has been built, from which experimental measurements have verified the discussed performance and feasibility of the proposed system.

关键词： sequential color display LED LCD

Design and Development of Database System for Titanium Alloys

在线全文

cnki会议

学校读者我要写书评

暂无评论

Design and Development of Database System for Titanium Alloy...

第二届亚洲材料数据库会议

作者： Yongqing Zhao~* Weidong Zeng Vice-General engineering Northwest Institute for Nonferrous Metal research Xi’an Shaanxi 710016 china

＜正＞With the increasing and extensive application of titanium alloys in the fields of aerospace, marine and energy industry etc.,the corresponding references and experimental data have increased ***,it is necessary for material researchers to solve the key problems of collection, collation and utilization for the multifarious ***,based on the database technology and modularization designing method,a database system for titanium alloys was developed using Visual Basic 6.0 object-oriented programming *** is an intelligent inquiry system concerning all kinds of information in the field of titanium *** database system consists of 5 modules such as the basic knowledge,the information inquiry,the application,the standard,and the data information management of titanium *** the help of the database system developed in this investigation,it is found that the information of titanium alloys could be scientifically classified and systematically *** system provides simple and recognizable user interfaces for ease of use,and it facilitates the related data and the highly efficient inquiring methods.

关键词： Titanium alloy Object-oriented Database Inquiry

resources Investigation and Ribosomal DNA ITS Sequence Analyses of Medical Plant of Rumex hastatus

在线全文

cnki会议

学校读者我要写书评

暂无评论

Resources Investigation and Ribosomal DNA ITS Sequence Analy...

中华中医药学会第九届中药鉴定学术会议

作者： ZHENG Shui-qing~1,ZENG Ming~2,CHEN Wan-sheng~1,MA Ya-jun~3,Ding Ru-xian~1,QIAO Chuan-zhuo~1,CAO Hui~4 (1.College of Pharmacy,the Second Military Medical university,Shanghai 200433,china 2.Department of Pharmacology, General Hospital of Beijing Military Area,Beijing 100700,china,3.Department of Basic Medicine of the Second Military Medical university,Shanghai 200433,china 4.national engineering research center for Modernization of Traditional Chinese Medicine,Zhuhai 519020,china)

Objective:To investigate the resources of medical plants of Rumex hastatus in china for providing scientific data for their exploitation and to sequence its ribosomal DNA ITS for providing DNA molecular markers for authenticating Rumex *** Field investigation,sample collecting and identifying,and specimens checking in some institutes of botany were carried *** DNA ITS was amplified by PCR using consensus primer set and its sequence was determined by PCR direct *** Rumex hastatus is growing in Yunnan、Sichuan,southeast of Tibet and west of Guizhou. resources of Rumex hastatus are relatively rich in above *** lengths of its internal transcribed spacer 1,5.8S ribosomal RNA gene and internal transcribed spacer 2 are respectively 199bp,165bp and *** Rumex hastatus has values of development and utilization and DNA sequencing could be a useful and reliable tool in the identification of Rumex hastatus.

关键词： Rumex hastatus resources investigation ribosomal DNA internal transcribed spacer

束晕-混沌的复杂性理论与控制方法及其应用前景

在线全文

cnki会议

学校读者我要写书评

暂无评论

物理学进展 2003年第3期23卷 321-388页

作者：方锦清陈关荣中国原子能科学研究所北京27581信箱102413 香港城市大学混沌控制与同步学术研究中心

　本文系统论述涉及强流加速器等强流离子束装置中产生的束晕混沌的复杂性理论与控制方法及其应用前景。强流离子束在核材料生产与增殖、洁净核能、放射性废物嬗变、放射性药物生产、重离子聚变、高能物理、核科学与工程、国防与民用... 详细信息

　本文系统论述涉及强流加速器等强流离子束装置中产生的束晕混沌的复杂性理论与控制方法及其应用前景。强流离子束在核材料生产与增殖、洁净核能、放射性废物嬗变、放射性药物生产、重离子聚变、高能物理、核科学与工程、国防与民用工业和医疗等许多方面都有极其重要的应用潜力和诱人的发展前景。尤其是,近年来强流加速器驱动的放射性洁净核能系统是国内外关注的热门课题,因为它比常规核电更安全、更干净、更便宜。但是,强流离子束形成的束晕混沌的复杂性现象已引起了国内外广泛关注,需要加以抑制、控制和消除这类现象,解决这一难题已经成为强流离子束应用中的关键问题之一。目前不仅必须深入研究这类束晕混沌的复杂特性及其产生的物理机制,而且需要研究如何实现对束晕混沌的有效控制,并寻求和发展其新理论、新方法和新技术。这就向强流离子束物理和非线性-复杂性科学及其技术提出了一系列极富挑战性的新课题。本文结合国内外的研究概况,根据我们多年来的研究成果,特别是我们首创性地提出了一些束晕混沌的有效控制方法,它们包括:非线性反馈控制法,小波反馈控制法,变结构控制法,延迟反馈控制法,参数自适应控制法等,进行重点的介绍。

关键词：束晕-混沌控制复杂性理论控制方法强流加速器等强流离子束装置放射性洁净核能系统

在线全文

学校读者我要写书评

暂无评论

交互作用下磷石膏砌块的最佳配比的研究

武汉工程大学学报 2011年第8期33卷 86-89,94页

作者：王培雄宾晓蓓杨欢王胜军薛俊陈家藏曹宏武汉理工大学资源与环境工程学院湖北武汉430070 武汉工程大学国家磷资源开发利用工程技术研究中心湖北武汉430074

磷石膏是磷化工产生的工业废渣,已严重危害生态环境,将其制备成建筑砌块,变废为宝具有重大现实意义.通过极端顶点混料设计方法研究了配比对磷石膏砌块7 d强度的影响,得到最佳配比为:磷石膏/生石灰/粉煤灰/水=47/15/30/8.典型样品的SEM、... 详细信息

磷石膏是磷化工产生的工业废渣,已严重危害生态环境,将其制备成建筑砌块,变废为宝具有重大现实意义.通过极端顶点混料设计方法研究了配比对磷石膏砌块7 d强度的影响,得到最佳配比为:磷石膏/生石灰/粉煤灰/水=47/15/30/8.典型样品的SEM、XRD分析表明,钙矾石和CSH的大量形成并紧密包裹在粉煤灰玻璃球周围是形成强度的关键.

关键词：磷石膏极端顶点设计抗折强度耐水性

在线全文

学校读者我要写书评

暂无评论

第八届中国生物毒素学术研讨会

作者： Zhan-Tao Bai~￡ Tong Liu~$ Xue-Yan Pang~§ Yong-Hua Ji§ ~￡College of life Sciences,Yan''an university Shaanxi engineering and technological research center for conservation and utilization of regional biological resources,Yan''an 716000,P.R.china ~§School of life Sciences,Shanghai university,Shanghai 200444,P.R.china ~$Graduate School of the Chinese Academy of Sciences,Institute of Physiology,Shanghai Institutes for Biological Sciences,Chinese Academy of Sciences,Shanghai 200031,P.R.china.

＜正＞The sting by scorpion Buthus Martensi Karsch （BmK） could cause severe ongoing pain,inflammation and burning sensation for a long *** mimic these natural sting-induced clinical pain syndromes,subcutaneous intra... 详细信息

关键词： Scorpion venom BmK I Paw inflammation Spontaneous pain Thermal and mechanical hypersensitivity Sodium channels

在线全文

cnki会议

学校读者我要写书评

暂无评论

北京市农业用水问题及对策研究

节水灌溉 2008年第12期 20-23页

作者：闫华赵春江郑文刚国家农业信息化工程技术研究中心农业部农业信息技术重点开放实验室北京100089

北京市为资源型重度缺水地区,水资源的需求量随着经济发展和人口的增长而骤增,供需矛盾日益加剧。农业用水是用水大户,接近全市用水的40%。水资源紧缺导致北京农业水资源严重不足,而农业用水浪费现象还普遍存在,节水农业是解决北京水资... 详细信息

北京市为资源型重度缺水地区,水资源的需求量随着经济发展和人口的增长而骤增,供需矛盾日益加剧。农业用水是用水大户,接近全市用水的40%。水资源紧缺导致北京农业水资源严重不足,而农业用水浪费现象还普遍存在,节水农业是解决北京水资源问题的重要途径之一。概述了北京地区的农业水资源的现状,阐述了北京农业用水特点,分析了农业用水中存在的主要问题,从优化种植结构、雨洪利用、农艺节水、工程节水以及管理节水等方面提出了农业节水的对策措施和建议。

关键词：水资源农业节水北京

efficient Synthesis of 1,3-Disubstitutedimidazole-2-selones

在线全文

学校读者我要写书评

暂无评论

Efficient Synthesis of 1,3-Disubstitutedimidazole-2-selones

第一届硒与环境和人体健康国际会议

作者： R Li X.F.Wang X.H.Yuan S.D.Wang and S.W.Lu~* national engineering research center for Catalysis Dalian Institute of Chemical Physics Chinese Academy of Sciences 457 Zhongshan Road Dalian Liaoning 116011 P.R.china.

＜正＞Introduction Chemistry of imidazole-2-selone derivatives has attracted great attention recently because:（1） the imidazole-2-selone derivatives could serve as donors towards halogens in a fashion similar to many other selone derivatives,affording charge-transfer complexes of spoke structures or T-shaped structures;（2） some of the imidazole-2-selone derivatives are bioactive and promising *** have also reported that some of imidazole-2-selones are efficient catalysts for oxidative carbonylation of organic *** their important chemistry synthetic methodologies to imidazole-2-selone derivatives have not been extensively *** route to 1,3-disubstitutedimidazole-2-selone derivatives was to react elemental Selenium（Se） with the N-heterocyclic carbenes（NHCs） prepared

关键词：