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滤纸条末端形状对色素带平直度的影响
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作者 徐彤 《实验教学与仪器》 2019年第7期76-78,共3页
人教版高中生物教材必修1有“绿叶中色素的提取和分离”实验,但该实验层析时“为什么需要在滤纸条末端剪去两个角”“剪怎样的角”一直是困惑一线教师的热门话题。为此,对滤纸末端实施有规则的“减”和“加”两种变形剪角,可以顺利得出... 人教版高中生物教材必修1有“绿叶中色素的提取和分离”实验,但该实验层析时“为什么需要在滤纸条末端剪去两个角”“剪怎样的角”一直是困惑一线教师的热门话题。为此,对滤纸末端实施有规则的“减”和“加”两种变形剪角,可以顺利得出“如何剪角需根据滤纸条宽度而定”的初步结论。 展开更多
关键词 滤纸条 末端形状 色素带 层析法 平直程度
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Urban Three-dimensional Expansion and Its Driving Forces——A Case Study of Shanghai,China 被引量:20
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作者 SHI Longyu SHAO Guofan +4 位作者 CUI Shenghui LI Xuanqi LIN Tao YIN Kai ZHAO Jingzhu 《Chinese Geographical Science》 SCIE CSCD 2009年第4期291-298,共8页
Urban expansion is a phenomenon of urban space increase,and an important measuring index of the process of urbanization.Taking Shanghai as an example,the changes of urban average height and built-up area were studied ... Urban expansion is a phenomenon of urban space increase,and an important measuring index of the process of urbanization.Taking Shanghai as an example,the changes of urban average height and built-up area were studied to represent city's vertical and horizontal increases respectively,and statistical methods were used to analyze the driving forces of urban expansion.The research drew following conclusions:1) The urban expansion process of Shanghai from 1985 to 2006 had a clear periodic feature,and could be divided into three stages:vertical expansion in dominance,coordinated vertical and horizontal expansion,and horizontal expansion in dominance.2) The average height and quantity of buildings in core city were significantly bigger than those in suburbs,but the changing speed of the latter was faster.And 3) urbanization process was the major driving force for the city's horizontal expansion,while industrial structure improvement was the key driving factor for the vertical expansion.Those two driving forces were simultaneously affected by city's political factors. 展开更多
关键词 urban expansion three-dimensional space URBANIZATION urban vertical expansion urban horizontal ex-pansion SHANGHAI China
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