如图所示电路中,A1和为理想电流表,示数分别为和I_2 ,R1:R2:R_3=1 :2:当a、b两点间加以aR:R2R3A2恒定的电压U后,下列结论正确的是( ) A. ::4 B. ::9 C. 将、换成理想电压表,其示数之比为3:5 D. 将、换成理想电压表,其示数之比为1:1 ...
摘要: PROBLEM TO BE SOLVED: To provide a built-up wall construction method which allows the operator to check conditions of concrete (a hardening state and a possibility of mixture of air bubbles) in a foamed plastic arranged outside a concrete wall surface....