1.液体在两头开口的等横截面U形管中振荡,液柱长L,液面上方为大 气压强P,忽略粘性摩擦力和表面张力,求液柱运动规律。 解:液体是不可压缩的,故液体在同一瞬时的速度=v(t)处处相等,只 是时间的函数,且等于

Why Use Instrumental Variables? e Instrumental Variables(IV)estimation is used when your model has endogenous xs That is, whenever Cov(x,l)≠0 Thus. i can be used to address the problem of omitted variable bias 2 Additionally iv can be used to solve the classic errors-in-variables problem Economics 20- Prof anderson

Stationary Stochastic Process e A stochastic process is stationary if for every collection of time indices 11 e Thus, stationarity implies that the x,'s are dentically distributed and that the nature of any correlation between adjacent terms is

Parallels with Simple regression Bo is still the intercept B, to Bk all called slope parameters u is still the error term(or disturbance) Still need to make a zero conditional mean assumption, so now assume that E(lx,x2…,x)=0 Still minimizing the sum of squared residuals. so have k+l first order conditions Economics 20- Prof anderson

一、R、L、C串联谐振电路 二、串联电路 三、矢量图

then there exists AE R\ such that (Kuhn-Tucker condition) G(s') =0 and 1. Lagrange Method for Constrained Optimization FOC: D.L(,\)=0. The following classical theorem is from Takayama(1993, p.114). Theorem A-4 (Sufficieney). Let f and, i= ,..m, be quasi-concave, where Theorem A-1. (Lagrange). For f: and G\\, consider the following G=(.8 ) Let r' satisfy the Kuhn-Tucker condition and the FOC for (A.2). Then, x' problem is a global maximum point if max f() (1)Df(x') =0, and f is locally twice continuously differentiable,or

塞曼效应 1896年塞曼( Zeeman)发现当光源放在足够强的磁场中时,原来的一条光谱线分裂成几条」 光谱线,分裂的谱线成分是偏振的分裂的条数随能级的类别而不同。后人称此现象为塞曼效 早年把那些谱线分裂为三条而裂距按波数计算正好等于一个洛伦兹单位的现象叫做正 常塞曼效应(洛伦兹单位L=eB/4mc)。正常塞曼效应用经典理论就能给予解释

中药材质量标准 中文名弗朗鼠李皮 汉语拼音 Fulangshuli Pi 英文名 CORTEX FRANGULAE 来源本品为鼠李科植物弗朗鼠李树 Rhamnus frangula L.( Frangula alnus Miller) 的干燥枝皮或干皮。进口商品分弗朗鼠李皮和弗朗鼠李皮粉。 性状弗朗鼠李皮本品呈卷筒状或槽状,厚0.5~2mm。外表面灰棕色或棕褐色, 稍有纵皱纹,有明显的长椭圆形横向皮孔,灰白色

中药材质量标准 中文名马钱子 汉语拼音 Maqianzi 英文名 SEMEN STRYCHNI 来源本品为马钱科植物马钱 Strychnos nux- vomica L.的干燥成熟种子。 性状本品呈纽扣状圆板形,常一面隆起,一面稍凹下,直径1.5~3cm,厚0.3 06cm。表面密被灰棕色或灰绿色绢状茸毛,自中间向四周呈辐射状排列,有 丝样光泽。边缘稍隆起,较厚,有突起的珠孔,底面中心有突起的圆点状种 脐

3.1直线 启动Line命令的方法有如下几种: 一、在命令行输入Line或L。 二、在绘图菜单中单击“直线”。 三、在绘图工具栏上单击直线图标