美国物理学家密立根历时七年之久,通过测量微小油滴所带的电荷,不仅证明了电 荷的不连续性,即所有的电荷都是基本电荷e的整数倍,而且测得了基本电荷的准确 值。电荷e是一个基本物理量,它的测定还为从实验上测定电子质量、普朗克常数等其 他物理量提供了可能性,密立根因此获得了1923年的诺贝尔物理学奖 密立根油滴实验用经典力学的方法,揭示了微观粒子的量子本性。因为它的构思巧 妙,设备简单,结果准确,所以是一个著名而有启发性的物理实验

Text B 1. some time: a certain period of time e.g. the fire went for some time before it was brought under control. atatad the Cf. sometime: at some uncertain or unstated time in the future or in the past e.g. we'll take our holiday sometime in August. Our house was built sometime around 1905

一、电场线 电场线： 1、曲线上每一点的切线方向表示该点电场强度E的方向。描述电场分布情况的曲线。 2、曲线的疏密表示该点处场强E的大小。即：垂直通过单位面积的电场线条数，在数值上就等于该点处电场强度的大小

Detailed stud 1. hard: with great effort e.g. looking hard at this picture. think hard and work hard 2. hardly: almost not e.g. he could hardly wait to hear the news There's hardly any coal left. 3. .. than employees did in 1979

Consider a digraph G = (V, E) with edge-weight function w : E → R. The weight of path p = v1 → v2 → L → vk is defined to be

Definition. A directed graph (digraph) G = (V, E) is an ordered pair consisting of • a set V of vertices (singular: vertex)

The foundation of E.P.: before 1920s Wundt,1879: methodology James, “Talks to the teachers” 1899; “The principles of psychology”1890; Dewey: apply psychology to education

1. M. F. Egan, M. Kojima, J. H. Callicott, T. E. Goldberg, B. S. Kolachana, E. Zaistev, A. Bertolino, B. Gold, D. Goldman, M. Dean, B. Lu, (co-corresponding author) and D. R. Weinberger. (2003) The BDNF val66met polymorphism affects activity-dependent secretion of BDNF and human memory and hippocampal function. Cell 112, 257-269

Text A: fantasy, suspicion, injection, deputy, considerate, restore, estate, fantastic, multiple, furnish, deceive, commission, substantial, arrest, motive, justify exceeding, swear, disguise, switch e Text B: romantics, mysterious, e it, sigh, simplify, standpoint, heave, shiver, 2. Key phrases and expressions Text A: raise a glass to, turn out, buy up, live out, add on, fix up, sell sth at a loss Text B: read about, for one thing, in the night, make an appointment, switch on, raise the devil answer the door. stare after 3. Key structures

Daniel E Prober is in the Departments of Applied Physics and Physics, Yale University, NewHaven, Connecticut 06520-8284 USA. e-mail: daniel.prober@yale.edu Astronomers crave a detector sensitive enough to detect a single photon and determine its energy. new single-pixel