问题 问答题 论述题

论述产生印刷压力的原理。

答案

参考答案:

印刷压力一般指的是,油墨转移过程中压印体在压印面上所承受的压力,即沿压印面的法向,指向压印面的力。印刷压力就是强制地使压印体充分接触,以利于油墨的转移。但印刷压力并非愈大愈好,而是要适中。印刷压力过大,会加剧印版的磨损、增加印刷机的负荷,若用网线版印刷,还会因油墨的过分铺展而影响印刷品的阶调和颜色的再现;若用凸版印刷,则会造成印刷品背面出现凸痕甚至破损。印刷压力过小,会引起承印材料与油墨接触不良,转移墨量不足,印刷品墨迹浅淡不清,若用网线版印刷,甚至会造成印刷品高光部位的网点因着墨不良而丢失。

阅读理解

阅读理解。

根据短文内容,从短文后的选项中,选出能填入空白处的最佳选项。选项中有两项为多余选项。

     My mother is a diligent and kind woman. She is very busy from morning till night. As a teacher, she

works hard.    1    Both my brother and I love her dearly as she loves us.

My mother has been teaching math at a middle school in my hometown. She goes to work early in the

morning and does not return home until late in the afternoon.    2    She treats them with patience and

teaches them well. For her excellent quality and very good teaching results, she has been elected as a

model teacher several times.

       3  .  Every day, when she comes back home from work, she sets about doing housework, sweeping

the living room and bedrooms or cleaning the furniture, and putting everything in good order. She seems

to be busy all the time. As she has been very busy working every day, she looks older than her age. But

she looks as cheerful and happy as ever. Mother never buys expensive dresses for herself, but she often

buys some inexpensive but high quality clothes for us.    4    She just eats a plain meal outside when she is

too busy to cook herself. She lives a busy yet simple life, without any complaints.

     Often she says to us, "work while you work, and play while you play. That is the way to be happy

and gay. If you do not work, you will become lazy and be of no use to society". What a piece of good

advice this is!    5  .  This advice of hers will always serve as a guide to my behavior. My mother is great

indeed, and I always feel proud of her.

A. She enjoys listening to classic music.

B. As a mother, she takes good care of us and gives us every comfort.

C. She loves her students and cares for them.

D. She never goes to expensive restaurants to enjoy meals.

E. My mother is hard-working and never wastes money.

F. I never forget it and always bear it in my mind.

G. Can you tell us something about your mother?

多项选择题