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For a nonholonomic system, a new type of Lie symmetrical non-Noether conserved quantity is given under general infinitesimal transformations of groups in which time is variable. On the basis of the invariance theory of differential equations of motion under infinitesimal transformations for t and q_s, we construct the Lie symmetrical determining equations, the constrained restriction equations and the additional restriction equations of the system. And a new type of Lie symmetrical non-Noether conserved quantity is directly obtained from the Lie symmetry of the system, which only depends on the variables t, q_s and \dot{q}_s. A series of deductions are inferred for a holonomic nonconservative system, Lagrangian system and other dynamical systems in the case of vanishing of time variation. An example is given to illustrate the application of the results. 相似文献
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信息社会中,计算机操作及计算机技术运用能力已成为大学生的基本能力要求之一,但是,目前高校计算机公共课教学中普遍存在厌学、逃课等学习倦怠现象.学习倦怠对学生的学业成就、身心健康等方面都有负面影响.从客观原因和主观原因两方面探讨了计算机公共课教学中学习倦怠产生的原因,并从大学生、学校、老师这三个角度提出了解决这些问题的应对策略. 相似文献
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