题目内容

压电材料主要包括:

A. 石英晶体
B. 压电陶瓷
C. 新型压电材料
D. 霍尔半导体

查看答案
更多问题

正压电效应指的是:某些电介质,当沿着一定方向对其施力而使它变形时,内部就产生极化现象,同时在它的一定表面上产生电荷,当外力去掉后,又重新恢复不带电状态的现象。

A. 对
B. 错

Translate theunderlined wordsinto Chinese.1. Other than a degree, from a college education I plan to pursue higher learning, to begin a career, and to make history in my family. (Text B, Unit 1)2. The job requires a high degree of skill.3. It will probably be a few degrees colder by the weekend.4. … a device in their eyeglasses may suggest a few meal options and then automatically place an order for them. (Text A, Unit 2)5. True leaders do not just give orders, but take time to listen to the advice of those around them.6. The doctor ordered me to stay in bed.

Transact-SQL通常称为

A. 结构化定义 语言
B. 结构化操纵语言
C. 结构化查询语言
D. 结构化控制语言

下列说法正确的是

A. SQL中局部变量可以不声明就使用
B. SQL中全局变量必须先声明再使用
C. SQL中所有变量必须先声明再使用
D. SQL中局部变量必须先声明再使用;全局变量是由系统提供的用户不能自己建立。

答案查题题库