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美国大学教育“双层制”的特征及其意义 被引量:1
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作者 李凤玮 周川 《江苏高教》 CSSCI 北大核心 2016年第6期64-67,共4页
霍普金斯大学于1876年创办研究生院,标志着美国大学教育"双层制"初步形成。"双层制"的基本特征是:在一所大学里,本科生教育主要在本科生学院进行;研究生教育主要在各专业学院进行。随着时代的发展,"双层制&qu... 霍普金斯大学于1876年创办研究生院,标志着美国大学教育"双层制"初步形成。"双层制"的基本特征是:在一所大学里,本科生教育主要在本科生学院进行;研究生教育主要在各专业学院进行。随着时代的发展,"双层制"在具体形式上发生了许多变化,产生了诸多变式,呈现出错综复杂的多样化局面。但从总体上看,"双层制"的基本要素在美国多数大学里依然保持着,其原因在于:"双层制"较好地满足了本科生教育和研究生教育的不同培养目标,协调了教学和科研的关系,促进了人财物力资源的合理调配。 展开更多
关键词 “双层制” 本科生学院 研究生学院
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Mechanism of ultrasonic-pulse electrochemical compound machining based on particles 被引量:2
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作者 张成光 张勇 张飞虎 《Journal of Central South University》 SCIE EI CAS 2014年第1期151-159,共9页
The electric double layer with the transmission of particles was presented based on the principle of electrochemistry.In accordance with this theory,the cavitation catalysis removal mechanism of ultrasonic-pulse elect... The electric double layer with the transmission of particles was presented based on the principle of electrochemistry.In accordance with this theory,the cavitation catalysis removal mechanism of ultrasonic-pulse electrochemical compound machining(UPECM) based on particles was proposed.The removal mechanism was a particular focus and was thus validated by experiments.The principles and experiments of UPECM were introduced,and the removal model of the UPECM based on the principles of UPECM was established.Furthermore,the effects of the material removal rate for the main processing parameters,including the particles size,the ultrasonic vibration amplitude,the pulse voltage and the minimum machining gap between the tool and the workpiece,were also studied through UPECM.The results show that the particles promote ultrasonic-pulse electrochemical compound machining and thus act as the catalyzer of UPECM.The results also indicate that the processing speed,machining accuracy and surface quality can be improved under UPECM compound machining. 展开更多
关键词 ULTRASONIC pulse electrochemical machining (PECM) cavitation catalysis removal mechanism PARTICLES electric doublelayer
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