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Df = Bcos37¡ã¡ÁL2 + Bsin37¡ã¡ÁL2= [2·Ö]
D t = [1·Ö]
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(2) ͨ¹ýÏßȦºá½ØÃæµÄµçºÉÁ¿ Q = [2·Ö]
(3) µ±ÏßȦƽÃæÓë´Å¸ÐÏßƽÐÐ, ¸ÐÓ¦µçÁ÷×î´ó, bc±ßËùÊܵݲÅàÁ¦Ò²×î´ó.
Em = BL¡ÁwL = BwL2
[2·Ö]
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