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简析提高英语口语表达能力的“开口”策略
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作者 吴丽娟 《长春师范大学学报(人文社会科学版)》 2012年第2期174-175,共2页
高职学生英语口语表达能力普遍不高。为满足学生的学业和就业需要,英语教师有必要着力提高学生的英语口语表达能力。本通过激励学生"敢于开口、善于开口、乐于开口"的教学方法的尝试和探索,指出这种方法的核心思想是把口语训... 高职学生英语口语表达能力普遍不高。为满足学生的学业和就业需要,英语教师有必要着力提高学生的英语口语表达能力。本通过激励学生"敢于开口、善于开口、乐于开口"的教学方法的尝试和探索,指出这种方法的核心思想是把口语训练贯穿到英语教学的各个环节中去。 展开更多
关键词 高职教育 英语口语 表达能力 “开口”策略
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Analysis and control of novel split-winding doubly salient permanent magnet motor for adjustable speed drive 被引量:6
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作者 程明 周鹗 《Science China(Technological Sciences)》 SCIE EI CAS 2001年第4期353-364,共12页
In this paper, a novel split-winding doubly salient permanentmagnet (DSPM) motor is proposed and the theoretical and experimental studies on the magnetic field, static characteristics and control strategy of this moto... In this paper, a novel split-winding doubly salient permanentmagnet (DSPM) motor is proposed and the theoretical and experimental studies on the magnetic field, static characteristics and control strategy of this motor are carried out. The steady-state and dynamic models are presented and the output power equation is derived. The feasibility of extending the operation range of the DSPM motor by using split-windings is proved. The finite element method is used to analyze the magnetic field, in which the leakage flux outside the stator circumference is taken into account. Based on the operation principle and the static characteristics of the motor, the control strategy and scheme are developed and implemented in a microcomputer-based controller. According to the features of the 4-phase 8/6-pole DSPM motor, a half-bridge power converter without neutral is adopted to reduce the number of power devices and to eliminate the problem of voltage unbalance in the split capacitors. The experimental results on the prototype machine not only verify the theoretical analysis, but also show that the proposed DSPM motor drive possesses good steady-state and dynamic performances, offering high efficiency over wide power range, and that the split-winding topology can effectively extend the operation range of the DSPM motor. 展开更多
关键词 doubly salient permanent magnet motor variable speed drive control strategy split-winding finite element leakage flux INDUCTANCE
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