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Water Security Problem in North China: Research and Perspective 被引量:12
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作者 XIA Jun LIU Meng-Yu jia shao-feng 《Pedosphere》 SCIE CAS CSCD 2005年第5期563-575,共13页
This paper addresses the emergence of water security problems in North China with the aim of highlighting key waterresources management and water security issues for the long-term development of North China. Three key... This paper addresses the emergence of water security problems in North China with the aim of highlighting key waterresources management and water security issues for the long-term development of North China. Three key problemsrelated to water resources and security issues in North China in the 21st century are addressed, namely 1) the watercycle under environmental change, 2) agricultural water saving, and 3) water security. Development of internationalresearch related to these issues is also reviewed. The research plan developed recently by the Chinese Academy of Sciences(CAS) is discussed and suggestions on research and development of water resources science in North China are presented.Thanks to focus on experimental catchments and dedicated research stations, a detailed knowledge of the water cycle onNorth China farmland has been compiled. A range of techniques that include isotope tracers has been used to acquirehydrologic data. Much research has been devoted to developing distributed hydrological models at different scales. In thewell irrigation district, five different water saving irrigation regimes have been investigated, and these regimes have hadwidespread application, and reduced water use 60-150 mm while they increased water use efficiency (WUE) by 20%-30%.Furthermore, preventing water pollution is the most essential step to ensure North China’s water security. 展开更多
关键词 中国 北方地区 环境变化 水资源管理 水安全 水循环
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The Effect of Wheat Mixtures on the Powdery Mildew Disease and Some Yield Components 被引量:4
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作者 LI Ning jia shao-feng +4 位作者 WANG Xiu-na DUAN Xia-yu ZHOU Yi-lin WANG Zong-hua LU Guo-dong 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2012年第4期611-620,共10页
Mixtures composed of five wheat cultivars,Jingshuang 16,Jing 411,Jingdong 8,Lunxuan 987,and Baofeng 104,with different levels of resistance against powdery mildew were tested for their potential containment of the dis... Mixtures composed of five wheat cultivars,Jingshuang 16,Jing 411,Jingdong 8,Lunxuan 987,and Baofeng 104,with different levels of resistance against powdery mildew were tested for their potential containment of the disease development in the field and for the influence on grain yield and the content of crude protein in the years 2007 and 2010.The plots were inoculated artificially with mixed isolates collected in the fields and propagated in the greenhouse and the disease was scored in 7 d interval during the two growing seasons.It was indicated that certain combinations,e.g.,Jingdong 8:Lunxuan 987,Jingdong 8:Baofeng 104,and Jing 411:Jingdong 8:Baofeng 104,showed positive efficacy on the mildew.The cultivar combinations tested in 2007 showed increase of grain yield,while most of the combinations tested in 2010 did not show the increase.The differences of the increases or decreases were not statistically significant except combinations Jing 411:Jingdong 8:Baofeng104,Jingshuang16:Jingdong8:Lunxuang 987 and Jingshuang 16:Jingdong 8:Lunxuan 987:Baofeng 104,which showed the decrease of the grain yield.The mixtures did not show influence on the content of crude protein in grain.More cultivar combinations need to be tested. 展开更多
关键词 wheat powdery mildew cultivar mixture AUDPC yield crude protein
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New progress of research on water cycle in atmosphere in China 被引量:4
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作者 Wang Guo jia shao-feng +8 位作者 Yu Gui-rui Xu Juan Wang Jin-xia Wang Qiu-feng Ge Quan-sheng Huang Ji-kun Xia Jun Li Li-fnjuan et al. 《Journal of Geographical Sciences》 SCIE CSCD 2001年第4期100-109,共10页
New progresses are introduced briefly about the water cycle study on atmosphere of China made in recent years. The introduction includes eight aspects as follows: 1) precipitation characteristics, 2) stability of clim... New progresses are introduced briefly about the water cycle study on atmosphere of China made in recent years. The introduction includes eight aspects as follows: 1) precipitation characteristics, 2) stability of climatic system, 3) precipitation sensitive region, 4) regional evaporation and evapotranspiration, 5) water surface evaporation, 6) vegetation transpiration, 7) cloud physics, and 8) vapor source. 展开更多
关键词 PROGRESS water cycle ATMOSPHERE
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水资源与社会经济发展要素时空匹配特征——以张家口为例 被引量:31
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作者 韩雁 贾绍凤 +1 位作者 鲁春霞 吕爱锋 《自然资源学报》 CSSCI CSCD 北大核心 2020年第6期1392-1401,共10页
水资源短缺已成为制约区域经济社会发展的重要因素,协调水资源与社会经济关系是水资源可持续利用的关键。以张家口为例,采用洛伦兹基尼系数和不均衡指数模型对水资源与社会经济发展要素的时空匹配特征进行研究,结果表明:2004—2015年张... 水资源短缺已成为制约区域经济社会发展的重要因素,协调水资源与社会经济关系是水资源可持续利用的关键。以张家口为例,采用洛伦兹基尼系数和不均衡指数模型对水资源与社会经济发展要素的时空匹配特征进行研究,结果表明:2004—2015年张家口水资源与人口、耕地面积分布处于"匹配比较合理"和"相对匹配"状态,水资源与经济布局匹配呈现出由"完全不匹配"状态逐渐转变为"相对不匹配"状态。在空间匹配演化方面,水资源与人口、耕地面积的匹配度变化不大。水资源与经济匹配结果表明在水资源禀赋越差的地区,经济增速越快,水资源与经济的空间匹配状况越差。张家口水资源与社会经济发展要素时空匹配特征研究,对于指导区域水资源合理开发利用具有重要的现实意义。 展开更多
关键词 水资源 时空匹配 基尼系数 不均衡指数 张家口
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中国水土资源本底匹配状况研究 被引量:38
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作者 孙侦 贾绍凤 +2 位作者 严家宝 朱文彬 梁媛 《自然资源学报》 CSSCI CSCD 北大核心 2018年第12期2057-2066,共10页
论文以中国水资源二级区为基本单元,利用单位面积水资源量法和基尼系数法,以二级区水资源总量和潜在可开垦耕地面积为数据基础,评价中国水土资源本底匹配状况,为中国水土资源优化配置提供科学依据。首先根据适宜农作物耕种的高程、坡度... 论文以中国水资源二级区为基本单元,利用单位面积水资源量法和基尼系数法,以二级区水资源总量和潜在可开垦耕地面积为数据基础,评价中国水土资源本底匹配状况,为中国水土资源优化配置提供科学依据。首先根据适宜农作物耕种的高程、坡度和土壤类型条件,得到中国潜在可开垦耕地分布;然后,计算单位潜在可开垦耕地面积水资源量,评价中国水土资源本底匹配分布状况;最后,绘制水土资源洛伦兹曲线,计算基尼系数,对中国水土资源本底匹配总体状况进行评价。研究结果表明:1)中国北部区域潜在可开垦耕地较多,西南部和南部沿海区域分布较少,未来具有较大耕地开发潜力的区域主要分布在北方;2)中国本底水资源和潜在可开垦耕地资源空间分布存在严重错位;3)较之已有研究成果中依据水资源量和耕地面积计算的基尼系数0.566,论文以本底水资源和潜在耕地为基础数据计算的基尼系数0.712要大很多,表征中国本底水土资源不匹配程度要严重得多,中国80%的水资源服务不到23%的潜在可开垦耕地。 展开更多
关键词 水土资源本底匹配 潜在可开垦耕地 单位面积水资源量 基尼系数
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外转子交替极伺服永磁电机低转矩脉动设计与综合优化
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作者 梁泳涛 贾少锋 梁得亮 《导航与控制》 2021年第5期61-70,共10页
针对伺服电机减少永磁体用量、降低转矩脉动的需求,研究了削弱外转子交替极永磁电机转矩脉动的方法。对交替极永磁电机转矩脉动的产生机理进行了分析,可以通过永磁体极弧系数优化、永磁机不等极弧系数配合和定子齿偏心结构等方法削弱电... 针对伺服电机减少永磁体用量、降低转矩脉动的需求,研究了削弱外转子交替极永磁电机转矩脉动的方法。对交替极永磁电机转矩脉动的产生机理进行了分析,可以通过永磁体极弧系数优化、永磁机不等极弧系数配合和定子齿偏心结构等方法削弱电机转矩脉动,运用有限元分析软件Ansys Maxwell对电机进行二维建模,并对比了不同优化方法对电机转矩脉动削弱的效果,最终验证了采用多种方法对外转子交替极永磁电机转矩脉动进行综合优化能够有效削弱电机的转矩脉动。 展开更多
关键词 交替极永磁电机 转矩脉动 不等极弧系数 定子齿偏心 优化分析
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