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中国城市多中心空间结构的发育程度、基本模式及影响因素——基于297个地级及以上城市的实证研究 被引量:1
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作者 张延吉 黄宏祥 林胜 《地理科学》 CSSCI CSCD 北大核心 2024年第5期766-774,共9页
利用高精度活动人口数据,整合空间自相关分析与多中心模型,识别2019年297个地级及以上城市的所有中心地,从中心数量、距离、均衡性评价多中心程度,基于前述3大指标归纳出10类城市空间结构模式。研究表明,除少量分散型城市,中心数越多,... 利用高精度活动人口数据,整合空间自相关分析与多中心模型,识别2019年297个地级及以上城市的所有中心地,从中心数量、距离、均衡性评价多中心程度,基于前述3大指标归纳出10类城市空间结构模式。研究表明,除少量分散型城市,中心数越多,相应城市越少;山地海岛、与邻省交界或发达城市更易远离主中心形成副中心;组团式布局的大城市和强县弱区型中小城市具有相对均衡的多中心,圈层扩张型城市则多呈极化格局。经济社会发展水平提高是形塑多中心结构的首要因素,自然地形起伏助推多中心发育,但政府搬迁、兴建开发区等外迁政策对多中心程度并无显著影响,修建道路也难以壮大新中心。可见多中心结构是经济社会高水平发展的产物,而非跨越式打造而成的。 展开更多
关键词 多中心程度 空间结构模式 负指数函数 空间自相关
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Optimization and mechanism of surfactant accelerating leaching test 被引量:6
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作者 艾纯明 吴爱祥 +1 位作者 王贻明 侯春来 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第5期1032-1039,共8页
To solve the problem of slow leaching speed of copper,surfactant was added into lixivium as leaching agent in the experiment.Based on physical chemistry and seepage flow mechanics,the leaching mechanics of surfactant ... To solve the problem of slow leaching speed of copper,surfactant was added into lixivium as leaching agent in the experiment.Based on physical chemistry and seepage flow mechanics,the leaching mechanics of surfactant was analyzed.The solution surface tension and surfactant adsorbing on the surface of ore have a significant impact on the surface wetting effect.With leaching rate for response,the study screened out three main factors by Plackett-Burman design method:the sulfuric acid concentration,surfactant concentration and temperature.Among these three factors,the surfactant concentration is the most important contributor to leaching rate.After obtaining the experiment center by the steepest ascent experiment,a continuous variable surface model was built by response surface methodology.By solving quadratic polynomial equation,optimal conditions for leaching were finally obtained as follows:the sulfuric acid concentration was 60 g/L,the surfactant concentration was 0.00914 mol/L,and the temperature was 45 °C.The leaching rate was 66.81% in the optimized leaching conditions,which was close to the predicted value,showing that regression result was good. 展开更多
关键词 SURFACTANT OPTIMIZATION LEACHING response surface
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