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Lecture D32: Damped Free Vibration Spring-Dashpot-Mass System k Spring Force Fs =-kx, k>0 Dashpot Fd =-cx, c>0 Newton's Second Law (mx =EF) mx +cx+kx (Define)Natural Frequency wn=k/m,and
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Lecture D33: Forced Vibration Fosinwt m Spring Force Fs =-kx, k>0 Dashpot Fd =-ci, c>0 Forcing Fext Fo sin wt Newton's Second Law (mix =CF) mx+cx+kx= Fo sin wt =k/m,=c/(2mwn)
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1几项重要基本概念 人因可靠性:人对于系统的可靠性所必须完成的活 动的成功概率。 人的可靠性,人为可靠性,人员可靠性 人因失误(《(humancrror)《):人未能精确地、恰当地、 充分地、可接受地完成所规定的绩效 标准范围内的任务
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– 1、掌握设备有形、无形损耗的类型及其对设备价值的影响; – 2、掌握设备折旧的含义、折旧方法与计算; – 3、掌握设备经济寿命概念及其计算; – 4、掌握存在新设备的设备更新原则及方法; – 5、掌握存在税收影响的设备租赁与购买比较决策
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(1)了解物化处理的主要方法,掌握粗大颗粒去除的原理,掌握悬浮物质和胶体物质去除的基本原理和常用方法; (2)了解溶解物质的处理方法,掌握几种重要方法的去除机理,掌握消毒原理,熟悉常用的几种消毒方法; (3)了解水的其他物理化学处理方法
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When the only force acting on a particle is always directed to- wards a fixed point, the motion is called central force motion. This type of motion is particularly relevant when studying the orbital movement of planets and satellites. The laws which gov- ern this motion were first postulated by Kepler and deduced from observation. In this lecture, we will see that these laws are a con- sequence of Newton's second law. An understanding of central
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In this lecture, we consider the problem of a body in which the mass of the body changes during the motion, that is, m is a function of t, i.e. m(t). Although there are many cases for which this particular model is applicable, one of obvious importance to us are rockets. We shall see that a significant fraction of the mass of a rocket is the fuel, which is expelled during flight at a high velocity and thus, provides the propulsive force for the rocket
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In this lecture, we will consider how to transfer from one orbit, or trajectory, to another. One of the assumptions that we shall make is that the velocity changes of the spacecraft, due to the propulsive effects, occur instantaneously. Although it obviously takes some time for the spacecraft to accelerate to the velocity of the new orbit, this assumption is reasonable when the burn time of the rocket is much smaller than the period of the orbit. In such cases, the Av required to do the maneuver is simply the difference between the
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生产过程 是指从准备生产开始,直到此 产品产出的全过程,是劳动者借助于劳 动资料直接或间接的作用于劳动对象, 使之成为产品的全过程。 医药企业的生产过程,主要包括生产准 备过程、基本生产过程、辅助生产过程、 生产结束清场与清洗和生产服务过程
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劳动定额 1.劳动定额的作用 劳动定额是在一定的生产技术和合理的劳动组织 条件下,为生产一定的产品或完成一定的工作所 规定的必要劳动量的标准
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