问题 问答题 简答题

简述改进传统淬火介质的思路。

答案

参考答案:

传统的淬火介质主要是水和油,想要改进传统淬火介质就得围绕这两种物质展开。

1)在水中加入无机盐和有机聚合物:这样可以程度不同地降低工件淬火时的低温冷却速度,因而能有效地防止工件的淬裂和变形,或者获得更高的淬火硬度和更深的淬硬层深度,从而提高工件的淬火质量。

2)在淬火油中加入添加剂:在淬火油中添加催冷剂、抗氧化剂、光亮剂等,形成高效多用新型淬火油,这样可以获得更强的冷却能力和更合理的冷却速度分布以及更长的使用寿命:或者更能保持工件表面的光亮性,更能减少工件变形和开裂,从而实现一油多用。此外改进淬火装置,使用物理的方法(搅拌、喷淋、超声波等)来强化冷却,也可以提高淬火油的冷却速度,满足淬火工艺要求。

问答题
阅读理解

Diet Coke, diet Pepsi, diet pills, no-fat diet, vegetable diet… We are surrounded by the word “diet” everywhere we look and listen. We have so easily been attracted by the promise and potential of diet products that we have stopped thinking about what diet products are doing to us. We are paying for products that harm us psychologically and physically.

Diet products weaken us psychologically. On one level, we are not allowing our brain to admit that our weight problems lie not in actually losing the weight, but in controlling the consumption of fatty, high-calorie(卡), unhealthy foods. Diet products allow us to jump over the thinking stage and go straight for the counter instead. All we have to do is to swallow or recognize the word “diet” in food brands.

On another level, diet products have greater psychological effects. Every time we have a zero-calorie drink, we are telling ourselves without our awareness that we don’t have to work to get results. Diet products make people believe that gain comes without pain, and that life can be without resistance and struggle.

The danger of diet products lies not only in the psychological effects they have on us, but also in the physical harm that they cause. Diet foods can indirectly harm our bodies because consuming them instead of healthy foods means we are preventing our bodies from having basic nutrients(营养成分). Diet foods and diet pills contain zero calorie only because the diet industry has created chemicals to produce these wonder products. Diet products may not be nutritional, and the chemical that go into diet products are potentially dangerous.

Now that we are aware of the effects that diet products have on us, it is time to seriously think about buying them. Losing weight lies in the power of minds, not in the power of chemicals. Once we realize this, we will be much better able to resist diet products, and therefore prevent the psychological harm that comes from using them.

小题1:The first paragraph mainly tells us _____.

A.diet products can bring out people’s potential

B.people have difficulty in choosing diet products

C.diet products are misleading people

D.people are fed up with diet products小题2:One psychological effect of diet products is that people tend to ____.

A.resist a variety of diet foods

B.hesitate before they enjoy diet foods

C.pay attention to their own eating habits

D.watch their weight rather than their diet小题3:The purpose of writing this passage is _________.

A.to warn people of the side effect of diet products

B.to tell people how to lose weight

C.to advise people to eat diet products

D.to introduce some diet products小题4: Which of the following shows the structure(结构) of the passage?

CP: Central Point      P: Point       Sp: Sub-point(次要点)   C: Conclusion