• 2022-06-18
    某三相电路中A,B,C三相的有功功率分别为PA,PB,PC,则该三相电路总有功功率P为( )。
    A:
    B:
    C:
  • B

    举一反三

    内容

    • 0

      延时环节<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/5c7e2dbac7e649e9ba2da3656a964d45.png" />,其相频特性和幅频特性的变化规律是( ) A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/0831ed5bb7a5495b9632eb9be36d703d.png" /> dB B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/a2358c63853d4f50a2cf9003407f588f.png" /> dB C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/23119fba416f46db820927d5fcd66a7d.png" /> dB D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/67d0e95b64db43bd9c955f6cf62e36a2.png" /> dB

    • 1

      下列不属于弹性力学平面问题的是( )。 A: 应力分量<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/14e55ab2cde14d22a44bff9ea88507d2.png">,只有应力分量<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/c3c1da2ca4e64ad19e0fbc1764ed6bcc.png">存在,且它们都仅为<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/7bffc15d98b240c584d659d1aa155670.png">和<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/dbee1ba1e52447b2bb076c7d812d3e5c.png">的函数 B: 应变分量<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/ea8a2b953bca4b598b6781db39c5f5bf.png">,只有应变分量<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/7877a5c9731d4b54b054875be6f3ea05.png">存在,且它们都仅为<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/7bffc15d98b240c584d659d1aa155670.png">和<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/dbee1ba1e52447b2bb076c7d812d3e5c.png">的函数 C: 位移分量<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/1e6aeef29fa74143bf306acfc598d7e4.png">,只有位移分量<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/0a59276fcf7e48d8bc4d1fb7313cc78d.png">存在,且它们都仅为<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/7bffc15d98b240c584d659d1aa155670.png">和<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/dbee1ba1e52447b2bb076c7d812d3e5c.png">的函数 D: 薄板弯曲问题

    • 2

      下列重氮离子进行偶联反应,哪个活性最大?( ) A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/971f9e07d154479180dc4b963ca9f331.png"> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/9bd8814746a84f9c81f49eefa5104a05.png"> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/936cd022f8df4a38abe5e1adaa8e97ad.png"> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/42005484f8fb4b1eac7615c0f6a9d46d.png">

    • 3

      一阶系统的时间常数为T,其单位斜坡响应为( ) A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/67e3c0d52e254647b240f082770206ce.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/77cbfaa7e7c347c9a502d35f1a8b3f5c.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/52b5ceec9ed54c339da07e37bc70083e.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/698f17a321984af99eeee8732000c80d.png" />

    • 4

      JK触发器的特性方程是( )。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/9dfa6d2bcd9d459ca40130783da2454a.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/1b99630eead9460aa41cd8b7e0a19594.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202102/5868e29bb93b4f9eb7adc83586f47786.png" />