CRH2型动车组车内信息显示器输入电压为（） A: DC100×（l士10%）V B: DC11O×（l士10%）V C: DC100×（l土5%）V D: DCI10×（l士5%）V

砂轮 1—300×50×75—A 60 L 5 V—35m/s，表示磨料代号的是（ ）。 A: A B: 60 C: L D: V

【单选题】V g 和V l 分别为饱和蒸汽和饱和液体的体积,x为湿蒸汽干度,则湿蒸汽的体积V为() A. V= x(V g - V l ) + V g B. V= (V g - V l ) + x V l C. V= x(V g - V l ) +V l D. V=(1-x)V g + x V l

船舶对水航速 V L ，对地航速 V G ，船速 V E ，如果 V L ＜V E ，而且 V G ＞V L ，则船舶航行在何种情况下。

对于饱和蒸汽进料，则有L’（ ）L ，V’（ ）V

精馏过程若为饱和液体进料，则()。 A: q = 1，L = L′ B: q = 1，V = V′ C: q = 1，L = V′ D: q = 1，L = V'

A signal s(t)=3cos(20pt) (V) is quantized by a uniform quantizer, the step size of the quantizer is 0.1(V), then the minimal number of quantization level is L , the number of bits per sample is at least R , and the variance of the quantization error is T ([img=22x22]1803a28ec2869ac.png[/img]). A: L=60, R=5, T=0.000833 B: L=30, R=5, T=0.000833 C: L=60, R=5, T=0.001667 D: L=60, R=6, T=0.000833

‏A signal s(t)=3cos(20pt) (V) is quantized by a uniform quantizer, the step size of the quantizer is 0.1(V), then the minimal number of quantization level is L , the number of bits per sample is at least R , and the variance of the quantization error is T ([img=22x22]1802e166a76be1c.png[/img]).‎ A: L=60, R=5, T=0.000833 B: L=30, R=5, T=0.000833 C: L=60, R=5, T=0.001667 D: L=60, R=6, T=0.000833

精馏过程的操作线方程的斜率是（）? V/R|V/L|L/V|R/V

某精馏塔操作时,若保持F、xF、q、D不变,增大回流比R,则L’、V’的变化趋势是( ) A: L’增大,V’减小 B: L’增大,V’增大 C: L’减小,V’减小 D: L’减小,V’增大