问题 问答题 简答题

外冷铁是怎样影响冒口补缩距离(补缩范围)的?

答案

参考答案:

外冷铁安放在冒口之间,相当于在铸件中间增加了激冷端,使冷铁两端向着两个冒口方向的温度梯度扩大,形成两个冷铁末端区,可以显著地增大冒口补缩距离或补缩范围;外冷铁置于板或杆件末端时,会便铸件末端区长度略有增加;用多边布置多块外冷铁的方法查以大大延长冷铁末端区的长度,从而增大冒口的补缩距离。总之,通过放置外冷铁,改变温度梯度,延长末端区,从而增加补缩距离。

阅读理解

阅读理解。

     While travelling, you'll be taking money, license or passport. Or you will buy something expensive

to take back home with you and you don't want it to get stolen. Here are some ideas on how to keep

your valuables (贵重物品) safe while traveling

      Plan ahead of time

      Think of what you really need and don't need to take on your trip. Only take the valuables that

you must have, not just ones that you would like to have.

      Carry your valuables on your person

      Something that is small, like cash and credit cards and your passport, can be carried in a money

wallet around your neck or in a money belt. This way, your valuables are hidden and right next to you,

where you know where they are at all times. Wear clothing that can hide the money belt.

      Carry larger valuables in your carry-on bag.

      If you can't fit it in your money wallet like some large valuables, you'd better put them somewhere

that you will keep touch with them. Your can put them on the plane, so you don't have to worry about

the airline losing your bag or someone stealing it from the belt after the flight before you get to it.

      Choose a hotel that has the front desk for valuables.

      This way, you don't have to worry about housekeeping getting hold of your valuables, or someone

stealing your valuables if your room is broken into. If you give the valuables to the front desk to keep

for you, choose a time when others are not looking.

1. The passage is mainly about _______.

A. what to do while travelling

B. how to carry your valuables on your person

C. how to keep your valuables safe while traveling

D. how to save money while travelling

2. You can carry all of the following valuables on your person EXCEPT _______.

A. your cash  

B. credit cards  

C. your passport    

D. your large valuables

3. Which kind of hotel can you choose while travelling according to the text?

A. You can choose a hotel with a lot of housekeepers for valuables.

B. You can choose a hotel with the front desk for valuables.

C. You can choose some cheap hotel.

D. You can choose a hotel with gatekeepers.

4. When you plan your travel ahead of time, you should make sure that _______.

A. you take valuables that you must have

B. you take valuables as many as possible

C. you take valuables that you would like to have

D. you take valuables that you have at home

5. Which of the following is TRUE according to the text?

A. Anything small must be carried in a money wallet around your neck.

B. You give valuables to the front desk at a hotel when others are looking.

C. You should wear a tight shirt while travelling.

D. You'd better put some large valuables in your carry-on bag.

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