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【多选题】
The launch orbits of spacecraft include: ____.
A.
Direct orbit injection
B.
Ballistic orbit injection
C.
Sliding orbit injection
D.
Transition orbit injection
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参考答案：
参考解析：
刷刷题刷刷变学霸
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【单选题】关于应力集中，一下哪个是错误的？
A.
因杆件载荷的改变而引起应力增加的现象称为应力集中
B.
对塑性材料,在应力集中的地方,当某点最大应力达到屈服极限时,将发生塑性变形,应力不再增加
C.
应力集丰对塑性粉料的强度影响很小
D.
脆性材料对应力集中敏感性甚强
【单选题】The black barrier area is located in ____ of the spacecraft’s return orbit.
A.
Deorbit stage
B.
Transition stage
C.
Re-entry stage
D.
Landing stage
【单选题】Students entering the design competition have to
A.
produce an energy-efficient design.
B.
adapt an existing energy-saving appliance.
C.
develop a new use for current technology.
【多选题】Which following is true about the re-entry angle of the spacecraft’s return stage? ____.
A.
The re-entry angle is the angle between the direction of the spacecraft’s flight speed and the local horizon.
B.
If the re-entry angle is too small, the spacecraft might been destroy due to high temperature.
C.
If the re-entry angle is too large, the spacecraft might skim the atmosphere.
D.
If the re-entry angle is too large, the spacecraft might been destroy due to high temperature.