时序逻辑电路如下图所示，其状态方程组是。（）<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202003/75fb6bc0f79d4332b5bdc69605562aba.png" > A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202003/5f963aec69ea48089a47d3cea9ec8f96.png" > B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202003/4a0262f12d584d86a85b3d0917a539aa.png" > C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202003/0733702e95cb4432b6847bfa287c88cc.png" > D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202003/b4619d1e5055487c984ea3b0b338ee02.png" >

利用替代法编程中常开触点对应的指令符号为：（）。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202006/b406fdddc2df4fa5a4101e1bb8cb9c59.png"> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202006/1fdbc7cdabc04afab6cf08b2dd2cb791.png"> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202006/9fc7f90d98ad49b8b3192379ace5d920.png"> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202006/4ed446acaf5142c48011611260c96457.png">

图所示圆截面杆,已知载荷F 1=200 kN,F 2=100 kN,AB段的直径d 1=40 mm,如欲使AB与BC段横截面上的正应力相同,试求BC段的直径。https://p.ananas.chaoxing.com/star3/origin/ebbf8bab1c04c0ab68376fea1065a2cc.png

图示结构支座B的反力为（设向上为正）：（ ）[img=232x113]1802d593f835870.png[/img] A: 26 kN B: 18 kN C: 8 kN D: -10 kN

用三线-八线译码器74LS138和辅助门电路实现逻辑函数<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202003/c871492b27384497a59d367211b93efb.png" >，应：（） A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202003/37b75181b0ad4fba92ee10f87ffa0bbb.png" > B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202003/453b2c724d1d4d41898e10c9ba036a39.png" > C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202003/2c10ee737f77406fa0457e0f02318515.png" > D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202003/9cbe3266526b4e8eab204cf96440be55.png" >