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教与学双边活动时间分配的“黄金分割率”
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作者 刘会元 《现代教育论丛》 2011年第Z1期39-41,共3页
课堂教学中极易产生两种极端:一是坚守传统,教师唱独角戏,"满堂灌"并依然灌得响亮。二是瞄准高考,大搞"题海战",课内作业、课外作业满天飞,各类课堂(包括公开课、示范课,课改课)都要强调学生的探究性活动。本文作... 课堂教学中极易产生两种极端:一是坚守传统,教师唱独角戏,"满堂灌"并依然灌得响亮。二是瞄准高考,大搞"题海战",课内作业、课外作业满天飞,各类课堂(包括公开课、示范课,课改课)都要强调学生的探究性活动。本文作者努力探索教时与学时应有一个非常合适的比例(1:0.618),才是教学效果的最大化。 展开更多
关键词 教与学双边活动时间 分配 “黄金分割率”
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Solution of rectangular bar forging with bulging of sides by strain rate vector inner-product
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作者 王磊 金文忠 +1 位作者 赵德文 刘相华 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第6期1367-1372,共6页
Abstract:ools. The effective strain rate for for determining the total pressure developed during forging of a rectangular bar forging with bulging was expressed in terms of four-dimensional strain rate vector. The in... Abstract:ools. The effective strain rate for for determining the total pressure developed during forging of a rectangular bar forging with bulging was expressed in terms of four-dimensional strain rate vector. The inner-product of the vector was termwise integrated and summed. The integral mean value theorem was applied to determining the ratio of the strain rate components and the values of direction cosine of the vector and then an analytical solution of stress effective factor was obtained. The compression experiments of pure lead bar were performed to test the accuracy of the solution. The optimized results of total pressure by golden section search were compared with those of the indicator readings of the testing machine. It indicates that the optimized total pressures are 2.60%-10.14% higher than those measured. The solution is available and still an upper-bound solution. 展开更多
关键词 rectangular bar forging BULGING strain rate vector inner-product golden section search
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