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【简答题】
The field current supply in older machines comes from a lower voltage direct current generator or exciter on the same shaft as the alternator. Modern machines however are either statically excited or of the high-speed brush-less type. The exciter is required to operate to counter the effects of power factor for a given load. The power factor is a measure of the phase difference between voltage and current and is expressed as the cosine of the phase angle. With a purely resistance load the voltage and the current are in phase, giving a power factor of one. The power consumed is therefore the product of voltage and current. Inductive or capacitive loads, combined with resistance loads, produce lagging or leading power factors which have a value less than one. The power consumed is therefore the product of current, voltage and power factor. The alternating current generator supplying a load has a voltage drop resulting from the load. When the load has a lagging power factor this voltage drop is considerable. Therefore the exciter, in maintaining the alternator voltage, must vary with load current and also the power factor. The speed change of the prime mover must also be taken into account.
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【单选题】以下意图哪个是用来描述ITERATOR(迭代器)?()
A.
使多个对象都有机会处理请求,从而避免请求的发送者和接收者之间的耦合关系
B.
用原型实例指定创建对象的种类,并且通过拷贝这些原型创建新的对象
C.
提供一种方法顺序访问一个聚合对象中各个元素,而又不需暴露该对象的内部表示
D.
运用共享技术有效地支持大量细粒度的对象
【单选题】以下意图哪个是用来描述TEMPLATE METHOD(模板方法)?()
A.
定义一个操作中的算法的骨架,而将一些步骤延迟到子类中
B.
为其他对象提供一种代理以控制对这个对象的访问
C.
将抽象部分与它的实现部分分离,使它们都可以独立地变化
D.
使多个对象都有机会处理请求,从而避免请求的发送者和接收者之间的耦合关系
【简答题】All my students in my class knew I was getting married in June and moving out of the state. I was sorry to see the month of June ____小题1:____; all my students wanted to learn more, They were obviously...
【简答题】如何评价混凝土的可泵性?
【单选题】以下意图那个是用来描述 TEMPLATE METHOD( 模板方法 ) ?( )
A.
定义一个操作中的算法的骨架,而将一些步骤延迟到子类中
B.
为其他对象提供一种代理以控制对这个对象的访问
C.
将抽象部分与它的实现部分分离,使它们都可以独立地变化。
D.
使多个对象都有机会处理请求,从而避免请求的发送者和接收者之间的耦合关系。
【判断题】In the matrix of transition probabilities, Pij is the conditional probability of being in state i in the future, given the current state j
A.
正确
B.
错误
【判断题】Construct SLR parsing action table from C: Let C = {I 0 , I 1 , I 2 , ..., I n }, the parsing action for state i is determined as follows: 1. If [A → α •a β ] is in I i and Goto(I i , a) = I j , then ...
A.
正确
B.
错误
【单选题】After I heard that I took a deferred pass in botany, I was in a ______ emotional state.
A.
highly
B.
doubtfully
C.
greatly
D.
nervously
【简答题】一级护理适用于哪些患者?包括哪些护理内容?
【判断题】Construct SLR parsing goto transition table from C: The goto transition for state i is constructed using the rule: If Goto(I i , A) = I j , then Goto[i, A] = j. Here ‘A’ is a non-terminal symbol. In a...
A.
正确
B.
错误
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