排序方式: 共有34条查询结果,搜索用时 15 毫秒
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TieYing Zhou Yun Zhang Yu Chen CunYue Lu DeYong Fu Yi Li XiaoPing Hu 《科学通报(英文版)》2009,54(20):3778-3783
This article reports a screw-driven polyhedron linear ultrasonic motor (USM) of nut-type. It is comprised of a stator, which is a threaded metal nut bonded with piezoelectric plates on its external surface, and a rotor with external threads, which engage with the internal threads of the stator. A traveling wave in the plane is stimulated on the stator when harmonic electric signals are applied to the piezoelectric plates. The traveling wave drives the rotor to rotate, and the threads transform the rotation into a linear motion. The lens can be fixed in the rotor and realize the integrated design of the auto focus system. This structure can omit retarder and directly drive to obtain a high accuracy of positioning, and it is shockproof. A mini AF cellular phone module (8.5 mm×8.5 mm×5.9 mm) driven by this motor was made and an image resolution of 3-5 MP was obtained in the module prototypes of the cellular phone. 相似文献
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文章通过世界著名科学家牛顿和爱因斯坦学习成长片断,说明现行教育必须减轻学生学习负担,应该对“小孩子有不可思议的力量”要有坚强的信念,积极主张推行陶行知先生倡导的“教学做合一”、“手脑双挥”、“即知即传人”和“小先生”等生活教育思想,进一步提高教育质量。 相似文献
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基于下刚果盆地中段实际地震剖面,结合物理模拟及离散元数值模拟方法,研究西非安哥拉被动大陆边缘下刚果盆地中段挤压带盐底辟构造的成因机制及演化过程,理解被动大陆边缘重力失稳构造的深层驱动机制,分析挤压作用下底辟构造间迷你盆地沉积中心的迁移与底辟作用的关系.结果表明,下刚果盆地中段挤压带的盐底辟构造演化过程与应力条件密不可分... 相似文献
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Xie Wenlong Author Vitae Author Vitae 《系统工程与电子技术(英文版)》2008,19(4):722-734
A new coordination scheme for multi-robot systems is proposed. A state space model of the multi- robot system is defined and constructed in which the system's initial and goal states are included along with the task definition and the system's internal and external constraints. Task accomplishment is considered a transition of the system state in its state space (SS) under the system's constraints. Therefore, if there exists a connectable path within reachable area of the SS from the initial state to the goal state, the task is realizable. The optimal strategy for the task realization under constraints is investigated and reached by searching for the optimal state transition trajectory of the robot system in the SS. Moreover, if there is no connectable path, which means the task cannot be performed Successfully, the task could be transformed to be realizable by making the initial state and the goal state connectable and finding a path connecting them in the system's SS. This might be done via adjusting the system's configuration and/or task constraints. Experiments of multi-robot formation control with obstacles in the environment are conducted and simulation results show the validity of the proposed method. 相似文献
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短串联重复(STR)的多态性分析是生物个体识别最有效的一种手段,在法医学鉴定中已被广泛用于身份识别.但目前使用的方法成本太高,以致不便在更广泛的范围推广.针对法医上常选用的4bp重复单位的STR基因座,采用PCR产物小于160bp的迷你STR(Mini STR)和优化聚丙烯酰胺凝胶电泳条件,提高分辨率,使重复单位之间能有效分辨.设计PCR引物,使STR基因座扩增产物的大小为4bp的倍数,应用8bp的DNA Ladder即能精确测定整数倍STR重复单位数.这一方法操作简便,成本低廉,尤其是用于制作人基因身份证,使得人人制作一张基因身份证成为可能. 相似文献
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短串联重复(STR)的多态性分析是生物个体识别最有效的一种手段,在法医学鉴定中已被广泛用于身份识别.但目前使用的方法成本太高,以致不便在更广泛的范围推广.针对法医上常选用的4 bp萤复单位的STR基因座,采用PCR产物小于160 bp的迷你STR(Mini STR)和优化聚丙烯酰胺凝胶电泳条件,提高分辨率,使重复单位之间能有效分辨.设计PCR引物,使STR基因座扩增产物的大小为4 bp的倍数,应用8 bp的DNALadder即能精确测定整数倍STR重复单位数.这一方法操作简便,成本低廉,尤其是用于制作人基因身份证,使得人人制作一张基凶身份证成为町能. 相似文献
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据英国每日邮报报道,日前,最新研制的“迷你芯片”不足15分钟便能精确率100%地探测到是否患有艾滋病。这种便携式验血装置可在几分钟内诊断是否被病毒感染,被称为发展中国家抵御艾滋病毒的重大突破。 相似文献