下面的式子哪一个是描述非稳态导热的第二类边界条件（ ）。
A:
B:
C:
D:
A:
B:
C:
D:
举一反三
- 图示应力圆对应于应力状态<img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/a61d48f304e9454fb6f3d8fcac0a5888.png" /> A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/fa83fd043ee946869755b338236b2b0e.png" /> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/77ff74928a3642928e805440db706068.png" /> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/6cce8e25b7ec4d00895cd86fabc16f64.png" /> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/62d9a4357886450cbfb0bde0deda67ec.png" />
- 在纯电容电路中，电压和电流的关系应为（ ）。 A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/3e829c34dee64700a6d7c47703fac813.png"> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/76f4755b138c42dcb27c8c006369dd09.png"> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/99d49adf0f7142ef91f9c78e42ba24b0.png"> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/d5322333240046d382b302f48318d1cb.png"> E: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/c5689885a941415493404a53dbf5e03b.png">
- 欠阻尼二阶系统的闭环极点分布图为（ ）。 A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/e26de5d73f984ba391a6ac30d8c6d4fe.png" /> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/11aa916316d34c4eb0ae8cafd3bdaeb0.png" /> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/31e7b12aeb2e427f882a4b430c6f6d94.png" /> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/aa587a3419434ed38f3114ee0eeaba96.png" />
- 在纯电感电路中，电压应为（）。 A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/fe9a2726638343cf8f66ce58ca5146cc.png"> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/0f360aa88e6d4c1993733df279cd3734.png"> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/08dcf081ff844b1e92735fc0b9d1a227.png"> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/344144b6bd8f4089899e73bd6daadc00.png">
- 下列各对函数中，两函数相同的是（ ） A: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/005a115bac08495eb95962c7071a78f1.png"> B: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/a527471aab444488884fca1d17d9d400.png"> C: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/3a0e26b4b4f44ceaa2ac479ce599077d.png"> D: <img src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/201908/3430e6031b074123a928985c91d4bf44.png">