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【简答题】
右图为手动铰车中所采用的蜗杆传动。已知m=8mm,d 1 =80mm ,蜗杆头数z 1 =1,蜗杆传动的传动比i=40,卷筒的直径D=250mm,试计算:(1)欲使重物上升1m,应转动蜗杆的转数; (2)设蜗杆和蜗轮间的当量摩擦系数为0.18,检验该蜗杆传动是否满足自锁条件; (3)设重物重Q=5kN,通过手柄转臂施加的力F=100N,计算手柄转臂的长度l的最小值(不计轴承效率)。
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【单选题】在财产保险的承保中，如果保险标的低于承保标准，保险人通常采用减少保险金额，或者使用较高的免赔额或较高的保险费率的方式承保。这一承保决策属于( )
A.
正常承保
B.
优惠承保
C.
有条件承保
D.
拒保
【简答题】在搜索引擎布尔检索中,要求检索结果中只包含所输入的两个关键词中的一个的关系的布尔关系词是________。
【单选题】The purpose of Bill Meyer’s investigation was_________
A.
to find out everything the banker did in his workday
B.
to find out whether Americans are working harder than ever before
C.
to prove that Americans are not working harder than ever before
D.
To prove that Americans are now doing a lot of unnecessary work
【单选题】下列有关滚装船特点描述正确的是:1、首跳板处必须设置首门与内门;2、首门位于干舷甲板之下;3、车辆通过舱内设置的活动斜坡道或升降平台作上下层间的移动
A.
①、②、③
B.
①、②
C.
①、③
D.
②、③
【单选题】What is the purpose of Bill Smith's AIDS foundation?
A.
To prevent people from contracting and spreading AIDS.
B.
To carry out research on how to prevent the spread of AIDS.
C.
To keep up with the rate of the epidemic growing.
D.
To promote AIDS awareness and prevention.
【单选题】The purpose of Bill Meyer’s investigation was ______.
A.
t o find out everything the banker did in his workday
B.
to find out whether Americans are working harder than ever before
C.
to prove that Americans are not working harder than ever before
D.
to prove that Americans are now doing a lot of unnecessary work
【简答题】下列有关古代发明创造的表述，正确的是（ ）。
【单选题】Which of the following is NOT the purpose that a bill of lading serves?
A.
It is a receipt.
B.
It is a check.
C.
It is a document of title.
D.
It is a contract.
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