在中性点直接接地系统中发生单相接地时表计指示如何变化?
参考答案:
发生单相接地时(如A相)UAB、UAC指示偏低,UBC指示无变化,A相电流增大。
幽门螺杆菌检测方法中特异性最高的是()
A.细菌培养
B.基因诊断
C.尿素酶试验
D.13C呼气试验
E.组织染色
Parents should be aware that communication between parents and their children is important,
________their heavy work loads. [ ]
A. but for
B. besides
C. because of
D. despite