【简答题】Last year, a report by a committee of education experts said that a lot of American students cannot write well. The report noted the concerns of business leaders and teachers. The experts said that mo...
【单选题】It’s a mistake to think of Florida only __ its tourist attractions. A. by means of B. in terms of C. in connection with D. by way of
【多选题】以外汇结算销售额的,其销售额的人民币折合率可以选择结算的( )
【单选题】a fire, hotel guests are askedto remain calm. A) In the event of B) In the time of C) As a result of D) By reason of
【单选题】一对作减速传动的标准渐开线直齿圆柱齿轮,小齿轮为1齿轮,大齿轮为2齿轮,材料、热处理及齿面硬度均相同,则正常条件下传动时,两齿轮间产生的接触应力和弯曲应力关系为 _______ 。
【单选题】一对作减速传动的标准渐开线直齿圆柱齿轮,小齿轮为1齿轮,大齿轮为2齿轮,材料、热处理及齿面硬度均相同,则正常条件下传动时,两齿轮间产生的接触应力和弯曲应力关系为 ______。
【简答题】一对正确啮合的标准渐开线齿轮增速传动,1为主动,2为从动。两轮材料热处理相同,工作时轮齿根部危险截面上的弯曲应力的关系是σ F1 ()σ F2 ;接触应力σ H1 ()σ H2 。
【简答题】齿轮传动时,两轮轮齿的齿面接触应力σH 相等 ,而两轮轮齿的齿根弯曲应力σF 。