第一章 大学之魂 第二章 青春在呼号 第三章 仁爱，天地最美 第四章 爱是难的 第五章 向往自由 第六章 寻找良知 第七章 星空让人敬畏 第八章 乡愁与家 第九章 为了忘却的记忆 第十章 英雄不仅是神话 第十一章 坚忍的山峦 第十二章 希望的红帆 第十三章 审视自我 第十四章 反讽与幽默 第十五章 诗意地栖居 第十六章 回归大自然

In lecture D9, we saw the principle of impulse and momentum applied to particle motion. This principle was of particular importance when the applied forces were functions of time and when interactions between particles occurred over very short times, such as with impact forces. In this lecture, we extend these principles to two dimensional rigid body dynamics. Impulse and Momentum Equations Linear Momentum In lecture D18, we introduced the equations of motion for a two dimensional rigid body. The linear momen- tum for a system of particles is defined

In this lecture, we will particularize the conservation principles presented in the previous lecture to the case in which the system of particles considered is a 2D rigid body. Mass Moment of Inertia In the previous lecture, we established that the angular momentum of a system of particles relative to the center of mass, G, was

A pendulum is a rigid body suspended from a fixed point (hinge) which is offset with respect to the body's center of mass. If all the mass is assumed to be concentrated at a point, we obtain the idealized simple pendulum. Pendulums have played an important role in the history of dynamics. Galileo identified the pendulum as the first example of synchronous motion, which led to the first successful clock developed

In this lecture, we will derive expressions for the angular momentum and kinetic energy of a 3D rigid body. We shall see that this introduces the concept of the Inertia Tensor. Angular Momentum We start form the expression of the angular momentum of a system of particles about the center of mass

D244BD RIGID BODY DYNAMICS KINETIC EWEGY In echure we derwed am kinenc a susem u dm T= Fere ts the velouty relanve to G. for a nald body we ca wate Uing the vechor nidontklyAxB=Ax

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

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)

一、抗菌肽简介 从微生物代谢产物中分离得到的一些多肽类抗 生素很早已经被应用; 但继1980年在美国天蚕体内发现了第一个动物 来源的抗生素多肽杀菌肽(cecropin)以来, 在昆虫、两栖类、水产动物、包括人在内的哺 乳动物甚至植物及细菌等广泛的生物谱中发现 了至少1700余种抗菌肽; 它们构成了宿主抵抗外来病原菌感染的第一道 防线

1.意外伤害(Unintentional Injury):突然发生的事件对人体所造成的肉体和精神上的伤害,原因包括物理、化学和生物等各种因素,是儿童致伤、致残、致死的主要原因之一 2.1985年美国国家儿童卫生与人类发展研究所(NICHD)学术会议对意外伤害的定义和分类进行标准化 3.国际疾病分类(ICD-10)将其列为单独一类疾病