1、某水泵以转速n为3600r／min旋转时，相对应的扬程H为128m，流量qV为1.23m3／min， 为满足该流量，拟采用比转数ns为85～133范围的单吸多级泵，试确定所用泵叶轮的级数i? 答案:解：试用2级时，i1＝2，比转速

Theory of Equivalence Relations (A, R) (E1) For all x : xRx. (E2) For all x, y : If xRy then yRx. (E3) For all x, y, z : If xRy and yRz then xRz. Logic in Computer Science – p.2/16

[1] Abramowitz, M., and Stegun, I., Handbook of Mathematical Functions, Dover Pub￾lications, New York, 1965. [2] Adair, R., Concepts in Physics, Academic Press, New York, 1969. [3] Anderson, J., and Ryon, J., Electromagnetic Radiation in Accelerated Systems, Physical Review, vol. 181, no. 5, pp. 1765–1775, May 1969

1948年，W.R.Evans根据反馈控制系统开环传递 函数与其闭环特征方程式之间的内在联系，提出了 一种非常实用的求取闭环特征方程式根的图解法－ 根轨迹法。 当系统特征方程式中的某一参数（例如开环增 益 、时间常数 ）连续由零变化到无穷大时，特征 方程式的根连续变化而在 平面上形成的运动轨迹， 即为闭环系统特征根的根轨迹

1、采用两级压缩的原因 单级压缩压缩比为10时最低蒸发温度 2、两级压缩制冷环 单级压缩的压比一般为:617≤82R210

The result appears to be trivial, but it is not. Notice that the “velocity increment” ∆V is actually equal to the decrease in orbital velocity. The rocket is pushing forward, but the velocity is decreasing. This is because in a r-2 force field, the kinetic energy is equal in magnitude but of the opposite sign

1 Theory of Isothermal Free Jet Free jet Jet without the limitation of solid boundary 1. General Properties National Lab. of Coal Combustion. HUST Wuhan 430074 P.R. CHINA

1. Classification wall turbulence -friction of wall free turbulence interaction of fluid layers homogeneous turbulence isotropic turbulence National Lab. of Coal Combustion. HUST Wuhan 430074 P.R. CHINA

化学工程学:以化学、物理和数学原理为基础,研究物料在 工业规模条件下,它所发生物理或化学状态变化的工业过程 R及这类工业过程所用装置的设计和操作的一门技术学科

31.2 Sources and Detectors Lucent Technologies Properties of Light. Absorption Coherence. Geometric Optics. Incoherent Light. Detectors, R.A.Becker