【单选题】钢轨探伤仪37°探头探测75kg/m钢轨时(声程为250mm),探头入射点距轨端()荧光屏出现钢轨底角反射波。
【单选题】钢轨探伤仪37°探头探测50kg/m钢轨时(声程为200mm),探头入射点距轨端( )荧光屏出现钢轨底角反射波。
【判断题】威尔逊法的基本假设认为在时间间隔中,加速度矢量是线性变化的。
【简答题】Zhang Wei is at the duty-free shop. He asked the salegirl Cassie to recommoend some gifts for his tourists. Listen to the conversation and fill in the blanks with what you hear.
【单选题】钢轨探伤仪测距为纵波声程250mm,用70°探头发现钢轨内有一斜裂纹回波3.2~4.4格,则该裂纹距探测面的垂直距离约为( )。
【单选题】超声波探伤仪测距为横波声程200mm,用0°探头发现钢轨内有一缺陷显示于4格,则缺陷距探测面的垂直距离为()
【多选题】医药消费者行为学是一门建立在( )科学理论基础上的应用种学。
【单选题】unit one conversation1
B.
The dorm is too crowded.
D.
She cannot afford to live on campus
【单选题】Unit 3- Long conversation How does the man spend his time on the morning train?
B.
Chatting with friends.
C.
Listening to the daily news.
D.
Planning the day's work.
【单选题】钢轨探伤仪37°探头探测43kg/m钢轨时(声程为200mm),探头入射点距轨端( )荧光屏出现钢轨底角反射波。