任何螺栓连接的构件,由于孔洞对构件截面有削弱,所以,强度验算只需要对净截面进行。
A campus emergency ______ occur at any time of the day or night, weekend, or holiday, with little or no warning.
2002年新配方口服补液盐(ORS)溶液的张力是
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