(9分)(1)电动汽车的动力系统由“10kW电机+144V镍氢电池”组成。 镍氢

题型:填空题

问题:

(9分)(1)电动汽车的动力系统由“10kW电机+144V镍氢电池”组成。

镍氢电池的使用可减少重金属离子污染,它采用储氢金属作为负极,碱液(主要是KOH)作为电解液,镍氢电池充电时发生反应:Ni(OH)2="==" NiO(OH)+1/2H2。其放电时正极电极反应式为_________________________________。

(2)二氧化锰、锌是制造干电池的重要原料,工业上用软锰矿(含MnO2)和闪锌矿(含ZnS)联合生产二氧化锰、锌的工艺如下:

①单质A为____________,单质B为______________。

②上述电解过程中,当阴极生成6.5gB时阳极生成MnO2质量为_________________。

③利用铝热反应原理,可从软锰矿中提取单质锰,写出其化学反应式:________________

考点:金属的电化学腐蚀
题型:填空题

阅读理解。

     Many facts suggest that children are overweight and the situation is getting worse, according to the doctors.

I feel there are a number of reasons for this.

     Some people blame the fact that we are surrounded by shops selling unhealthy, fatty foods, such as fried

chicken and ice cream, at low prices. This has turned out a whole generation of grown-ups who seldom cook

a meal for themselves. If there were fewer of these restaurants, then probably children would buy less take-

away food.

     There is another argument that blames parents for allowing their children to become overweight. I agree

with this, because good eating habits begin early in life, long before children start to visit fast food shops. If

children are given fried chicken and chocolate rather than healthy food, or are always allowed to choose what

they eat, they will go for sweet and salty foods every time, and this will carry on throughout their lives.

     There is a third reason for this situation. Children these days take very little exercise. They do not walk to

school. When they get home, they sit in front of the television or their computers and play computer games.

Not only is this an unhealthy pastime, it also gives them time to eat more unhealthy food. What they need is to

go outside and play active games or sports.

     The above are the main reasons for this problem, and therefore we have to encourage young people to be

more active, as well as steering them away from fast food shops and bad eating habits.

1. According to the text, what kind of children may eat more unhealthy food? [ ]

A. Those who often take exercise

B. Those who often watch television

C. Those who often have meals at home

D. Those who often walk to school

2. The author thinks that children are becoming overweight because _____. [ ]

A. their parents often cook meals for them

B. they are too busy to go out to play

C. they can't choose what to eat

D. there are many fast food shops around

3. The word steering in the last sentence most probably means _____. [ ]

A. forcing

B. guiding

C. driving

D. moving

4. The main purpose of the text is to _____. [ ]

A. tell a story

B. provide facts

C. give advice

D. compare opinions

题型:填空题

医学科研道德的根本原则是()。

A.献身医学

B.造福人类

C.团结同道

D.合理保密

E.严谨治学

题型:填空题

发动机工作时若燃烧浓混合气,则氧传感器的信号电压将()

A.变小

B.变大

C.不变

D.不确定

题型:填空题

如图18-5-11所示弹簧原长l=100mm,刚性系数k=4.9kN/m,一端固定在点O,此点在半径为R=100mm的圆周上。如弹簧的另一端由点B拉至点D,AC⊥BC,OA和BD为直径,则弹簧力所作的功为()。

A.20.3J

B.-20.3J

C.24.5J

D.-24.5

题型:填空题

采用管式静态混和器,构造简单,安装方便,混合快速而均匀。

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