下载APP
【单选题】
For two linear programs MaxZ = CX, AX ≤B, X ≥ 0 and Min W = YB, YA≥C, Y≥ 0 which are dual to each other, there is a relation ( )
A.
Z＞W
B.
Z=W
C.
Z≥W
D.
Z≤W
举报
参考答案：
参考解析：
刷刷题刷刷变学霸
举一反三
【单选题】There are three-phase windings with a mutual difference of 120 ° in the generator stator. When the symmetrical three-phase AC current flows, a () will be generated in the stator.
A.
Constant magnetic field
B.
Pulsed magnetic field
C.
A rotating magnetic field
D.
Perpetual magnetic field
【单选题】下列有关冠状动脉CTA检查心电门控技术的叙述,错误的是()
A.
目前CT冠脉动脉成像主要采用前瞻性心电门控技术
B.
回顾性心电门控技术使得按需选择从收缩期至舒张期的各种图像成为可能
C.
回顾性心电门控技术辐射剂量较大
D.
前瞻性心电门控技术在实际扫描中可因不能与实际心率相符而出现伪影
E.
前瞻性心电门控技术可以进行低剂量成像,对心律不齐的患者可进行自适应门控技术
【单选题】The optimality condition of dual simplex method for linear programming is ( )
A.
All test numbers are not positive
B.
all artificial variables are zero
C.
the number of column b is not negative
D.
all the above conditions should be met
【多选题】Why is the Jade Dragon Snow Mountain regarded as a treasure mountain for local people?
A.
the glacier
B.
precious wild animals
C.
various plants
D.
unique landscapes
【单选题】Synchronous generator stator rotating magnetic field has the characteristics of ().
A.
The number of magnetic poles and the speed of the rotor are the same, but the steering is different;
B.
The number of magnetic poles and steering is the same as that of the rotor, but the speed is different;
C.
It has the same speed and steering as the rotor, and the same magnetic pole logarithms.
【单选题】When the generator is running with pure resistance load, the phase difference between voltage and current is equal to ().
A.
180°
B.
90°
C.
0°
D.
5°
【单选题】The iteration of dual simplex method starts with ( ).
A.
the feasible solution of dual problem
B.
the optimal solution
C.
the feasible solution of the original problem
D.
the basic solution of the original problem
【单选题】When doing Beat 2 of the big Waist-twining Beating, lift up the right foot and withdraw to the right rear side with a distance about 40cm away from the left foot, point the tiptoe to （ ） degrees on t...
A.
30right
B.
45right
C.
45left
D.
30left
【单选题】When the generator is running with load, there is only energy () between the generator and the load.
A.
Consumption process
B.
Exchange process
C.
Consumption process and exchange process
D.
Not necessarily