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Novel high torque bearingless two-sided rotary ultrasonic motor 总被引：3，自引：0，他引：3
LI Xia CHEN Wei-shan XIE Tao LIU Jun-kao 《浙江大学学报(A卷英文版)》2007,8(5):786-792
Applications are limited at present because the currently available ultrasonic motors (USMs) do not provide suffi-ciently high torque and power. The conventional travelling-wave USM needs the bearing to support, which required lubricant. To solve the above problem, a bearingless travelling-wave USM is designed. First, a novel structure of the two-sided USM consisting of a two-sided teeth stator and two disk-type rotors is designed. And the excitation principle of the two-sided travelling-wave USM is analyzed. Then, using ANSYS software, we set up the model of the stator to predict the excitation frequency and modal response of the stator. The shape of the vibration mode was obtained. Last, the load characteristics of the USM are measured using ex-perimental method. The maximum stall torque and the no-load speed were obtained. The results showed that the characteristics of the two-sided USM are better than those of the conventional one-sided USM. 相似文献
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在课堂教学中,教师大量使用的语言是独白语。教师在使用独白语时应力避“干”、“淡”、“俗”、“病”、“乱”、“怪”等种种失误,追求语言的“准”、“达”、“活”、“权”,并注意与形体语言恰当结合,以取得课堂独白语的理想教学效果。 相似文献
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This study presents and verifies a new idea for constructing a rotary traveling wave ultrasonic motor (USM) that uses the
radial bending mode of a ring. In the new design, 20 trapezoid cross section slots are cut symmetrically in the outer surface
of a thick duralumin alloy ring, where 20 PZT stacks are nested. In each slot, two wedging blocks are set between the PZT
stack and the two sides of the slot respectively to apply preloading on the PZT ceramics. Two radial bending modes of the
stator that have a phase difference of a quarter wavelength on space are generated by using the d33 operating mode of the
PZT elements, and then a flexural traveling wave is formed by the superimposing of two standing waves whose amplitudes are
equal and phases are different by 90° temporally. Two conical rotors are pressed to each end of the ring type stator by a
coiled spring. The finite element method (FEM) simulation is developed to validate the feasibility of the proposed motor.
The maximal speed and torque of the prototype are tested to be 126 r/min and 0.8 N·m, respectively. 相似文献
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自由体现了人的本质、体现了社会关系的存在、体现了发展,追求自由是人的本质.自由教育是以自由为终极追求、以自由人为教育对象、以自由内容为媒介、以自由形式进行的教育.自由教育能引导与唤醒学生的生命意识,是实现创新、终身教育、自由社会的基础.中国的自由教育目前还存在着很多问题,亟待解决. 相似文献
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信息网络技术给高校德育带来新机遇的同时,也给高校德育带来了严峻挑战。在信息网络技术环境下,高校应采取积极措施,借助互联网实现高校德育的创新与发展。 相似文献
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运用症状自评量表(SCL-90)和教师一般情况调查问卷,采取方便取样和整群取样的方法对延安市幼儿园一线245名教师进行了调查,延安市幼儿教师的心理健康水平整体好于全国普通人群;阳性项目检出率为11.02%,心理问题排前三位的依次是强迫、敌对和抑郁;民办园教师的心理健康水平好于公办园教师;无职称教师的心理健康水平整体上好于初级、中级和高级职称教师;中专学历教师的心理健康水平整体上好于大专学历和本科学历教师。建议建立独立的幼儿园教师职称评审制度,增强幼儿园教师个人的心理调试能力和切实提高幼儿园教师的工资水平,提高幼教质量。 相似文献
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高师公共教育学课程教学改革探索 总被引：2，自引：0，他引：2
传统公共教育学教学存在很多弊端,严重影响了课程教学目标的实现。只有从课程内容、教学模式、教学评价等几方面积极改革,才能使公共教育学课程教学步入素质教育的轨道,并在一定程度上满足基础教育改革对教师教育的新需求。 相似文献
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