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试论我国蜜蜂育种概况 被引量:1
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作者 张健福 《养蜂科技》 2005年第2期23-27,共5页
回顾我国蜜蜂育种已走过30年历程。70年代以前我国饲养的是单一蜂种意大利蜂,它已成为我国的当家品种。由于未重视提纯复壮措施,加之长期采用了自养自繁的模式,山现了严重的近亲繁殖衰退现象。为此,1973年国家决定从国外引进了7个世界... 回顾我国蜜蜂育种已走过30年历程。70年代以前我国饲养的是单一蜂种意大利蜂,它已成为我国的当家品种。由于未重视提纯复壮措施,加之长期采用了自养自繁的模式,山现了严重的近亲繁殖衰退现象。为此,1973年国家决定从国外引进了7个世界著名蜂种,作为改良品种的育种素材。由于当时主管部门和养蜂界思想认识和学术理论水平比较滞后,未能采取行政手段科学地实施蜂种区域化规划管理。随后在“杂种优势”利用热和生产蜂场频繁地引种、换种以及全国性高频率地长途转地放蜂冲击下,于是,全国各地发生了灾难性的多品种、多代次的无控制的混乱杂交,又引起了蜂种普遍混杂退化。但从育种效益来看,在培育蜂蜜、王浆高产品系和杂交种等方面,还是取得了一定成绩。特别是新技术“蜜蜂育种数理工程技术”,可说是我国蜜蜂育种领域里的重大科技成果。 展开更多
关键词 中国 蜜蜂 纯种选育 杂交育种 杂种优势利用 区域化规划 种蜂行业监控
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对广西电网的思考
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作者 林荣华 《广西电力技术》 1999年第2期1-4,共4页
对广西电网的现状进行了简要的分析,指出了广西电网的主要特点和近年来运行中出现的新情况,提出了广西电网运行和发展的若干思路。
关键词 电网 联网运行 区域化规划 电力系统
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让农田防护林既能防护又能生财 被引量:1
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作者 沙鹏 《新疆林业》 2000年第5期14-15,共2页
关键词 农田防护林 生态经济型 经济效益 区域化规划 管理体制 经济效能 土地承包责任制 建设管理 经营管理 生态型
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Application of Land-use Change Model in Guiding Regional Planning:A Case Study in Hun-Taizi River Watershed,Northeast China 被引量:12
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作者 LIU Miao HU Yuanman +3 位作者 ZHANG Wei ZHU Junjun CHEN Hongwei XI Fengming 《Chinese Geographical Science》 SCIE CSCD 2011年第5期609-618,共10页
This paper firstly investigated the land-use and land-cover change (LUCC) in the Hun-Taizi River water- shed, Northeast China from 1988 to 2004 based on remotely sensed images and geographic information systems (GI... This paper firstly investigated the land-use and land-cover change (LUCC) in the Hun-Taizi River water- shed, Northeast China from 1988 to 2004 based on remotely sensed images and geographic information systems (GIS) technology. Then, using the famous land-use change model of Conversion of Land Use and its Effects at Small re- gional extent (CLUE-S), this paper simulated the land use changes under historical trend (HT), urban planning (UP) and ecological protection (EP) scenarios considering urban planning and ecological protection over the next 20 years. The simulated results under UP scenario in 2020 were compared with the planning map to assess the feasibility of us- ing land-use change model to guide regional planning. Results show that forest land, dry farmland, paddy, and shrub land were the main land-use categories. Paddy and dry farmland being converted to urban area and rural settlement characterized the land-use change from 1988 to 2004. The main land-use categories changed over time. Landscape-pattem fragmentation will be worse under HT and UP scenarios, but better in EP scenario. The comparing results of simulated map with planning map in 2020 show that land-use change model is powerful tool to guide regional planning. Land-use scenarios can support regional planning and policy-making through analyzing future consequences scientifically. 展开更多
关键词 land-use change model CLUE-S regional planning Hun-Taizi River watershed
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A Comparative Study of Methods for Delineating Sphere of Urban Influence: A Case Study on Central China 被引量:6
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作者 WANG Hao DENG Yu +1 位作者 TIAN Enze WANG Kaiyong 《Chinese Geographical Science》 SCIE CSCD 2014年第6期751-762,共12页
A number of urban and regional plans have been developed with the advancement of urbanization and regional integration, among which the delineation of sphere of urban influence and improvement of integration between t... A number of urban and regional plans have been developed with the advancement of urbanization and regional integration, among which the delineation of sphere of urban influence and improvement of integration between the city and its hinterland have be- come vital important for guiding practices. In terms of delineating sphere of urban influence, existing studies have been focused on static study by using single year data or single method, resulting in a lack of time-series longitudinal analysis or comprehensive analysis based on multiple methods This study emphasizes on comparing two methods from both the theoretical and empirical perspective. Both gravity model and improwd field model are applied to the selected study area for measurements and comparison, to explore their strengths and weaknesses. A research framework for comprehensive analysis on delineating sphere of urban influence is proposed. In the end, the differences of deli:aeating methods are illustrated and the feasibility of comprehensive analysis is discussed. Recommendations are provided for selecting appropriate methods for delineating sphere of urban influence or developing regional hierarchy system plans and urban spatial structure schemes. 展开更多
关键词 gravity model improved field model sphere of urban influence regional planning central China
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