0001下列泵中属于叶轮式泵的是 A.齿轮泵B.叶片泵 C.水环泵D.旋涡泵 0002不属于回转式容积式泵的是 A.水环泵B.齿轮泵C.螺杆泵D.旋涡泵 0003属于回转式容积泵的是 A.离心泵B.水环泵 C.旋涡泵D.轴流泵

1.一调光台灯由单相交流调压电路供电,设该台灯可看成电阻负载,在a=0°时输出功率为最 大值,试求功率为最大输出功率的80%、50%时的开通角a 2.一单相交流调压器,电源为工频220V,阻感串连作为负载,其中R=0.5Q,L=2mH试求: ①开通角a的变化范围;②负载电流的最大有效值③最大输出功率及此时电源侧的功率因数

Routing Must choose routes for various origin destination pairs o/d pairs) or for various sessions Datagram routing: route chosen on a packet by packet basis Using datagram routing is an easy way to split paths Virtual circuit routing: route chosen a session by session basis Static routing: route chosen in a prearranged way based on O/D pairs Eytan Modiano

一、例题精解 【例题2.1】在图2.2所示方框图中,N是一线性无源网络。当U1=1V,2=1A时,U3=0V:当U1=10V,2=0A时,U3=1V.试求当U1=0V,I2=10A时,U3=? 【解】应用叠加原理计算,则U3=U3+U3。其中3=AU是U1单独作用时的分量,U3=B2是l2单独作用时的分量,即

once oncu n a paiuicuia positon on DNA, a nucleosome remained fixed in place because of the tight association 30-nm 98A5 sequence-specific DNA-binding proteins nucleosome

reward l. reward sb. with sth.用某物报答酬谢/奖励某人 2. reward sb. for sth.因某事而报答酬谢奖励某人 3 rewarding adj. helpful有益的;值得做的e.g. Make the extra effort to impress theinterviewers and you will be likely to berewarded with a better job with a bettersalary.如果你能多花些心思,给面试的考官留下深刻的印象,那么你就可能得到一个比较好的、工资也很高的工作。次大注意区分与 award之间的不同

Virus a noncellular genetic element that enlists a cell for its own replication, it has an extracellular state. A virus particle containing nucleic acid surrounded by protein and other macromolecular components is called virion

一、n维向量 1.定义 n个有次序的数a1,a2,,an所组成的数 组称为n维向量,这n个数称为该向量的个分量, 第i个数a称为第i个分量

3.1运输问题的典例和数学模型 一、典例: 某食品公司经营糖果业务,公司下设三个工厂A1、A2、A3,四个销售门市部B1、B2、B3、B4。已知每天各自的生产量、销售量及调运时的单位运输费用情况。问:如何调运可使总费用最小?

Information content of a random variable Random variable x Outcome of a random experiment Discrete R V takes on values from a finite set of possible outcomes PMF: P(X=y)=Py) How much information is contained in the event X=y? Will the sun rise today Revealing the outcome of this experiment provides no information Will the Celtics win the NBa championship? Since this is unlikely, revealing yes provides more information than revealing Events that are less likely contain more information than likely events