The helical spring can no longer be used.

盘簧不能再用了.

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They were all treated with straight wire appliance and helical spring to expand clearance.

均采用直丝弓矫治器矫治,应用螺旋推簧扩展间隙及上颌前方牵引.

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Helical spring math models in the literature have constant pitch angle , which are not accurate enough.

螺旋弹簧的动力学模型一般都假设没螺旋角是常量.

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