【判断题】响应特性既依赖于输入又依赖于初始条件。例如,如果阶跃输入的幅度增加一倍,非线性系统就有可能从稳定变为不稳定。
【简答题】某柴油机压缩过程开始时,空气的压力为90kPa,温度为325K,压缩终了时空气的容积为原来的1/15。若采用定值比热,并假定压缩过程是可逆绝热的,试计算: (1)压缩终了的温度及压力 (2)过程中每千克空气热力学能的变化 (3)压缩每千克空气所需的功量
【单选题】In Rutherford atomic model alpha particles were stroked on ( )
【单选题】Alpha particles directly come from__________. 查看材料
【单选题】By immersing ore particles in water, ______.
A.
we can get ore particles of equal size
B.
we can purify aluminum particles
C.
we can filter out aluminum
D.
we can improve the working conditions around
【单选题】The particles of electromagnetic radiation given off by matter are known as ______.
【简答题】Alpha particles weigh about ___ ____ ____ than neutrons. a粒子比中子重大约3倍。
【单选题】What fraction of a beam of 7.7-MeV alpha particles incident upon a gold foil 3.0 × 10 -7 m thick is scattered by less than 1°? ( )