问题 问答题 论述题

什么是系列化设计?优缺点是什么?

答案

参考答案:

系列化设计方法是在设计的某一类产品中,选择功能,结构和尺寸等方面较典型产品为基型,以它为基础,运用结构典型化,零件通用化,标准化(结构的典型化)的原则设计出其他各种尺寸参数的产品构成产品的基型系列。

优点:

(1)可用较少品种规格的产品满足市场较大范围的需求

(2)可减少设计工作量,提高质量,减少开发风险,缩短研制周期

(3)可压缩工艺装备的数量和种类,缩短研制周期,减低成本

(4)零备件种类少,便于维修和售后服务

(5)伟变型设计提高基础。

缺点:产品具有通用性,用户只能在系列型谱内有限的品种规格中选取,参数功能不一定最符合,功能还可能冗余。

选择题
阅读理解

Most sharks are dangerous. The largest kind of sharks—the whale shark—has small teeth and is quite harmless to people. However, blue sharks, tiger sharks, white sharks and hammerheads are enemies of man.

Man-eaters are always a danger to swimmers in shark waters. Sometimes, though, men have used strange methods when they’re suddenly faced with a shark.

During world War Ⅱ, soldiers and sailors whose boats or planes were destroyed drifted(漂流) helplessly on the ocean in small rafts(筏子). While waiting to be saved, the men had to struggle to stay alive and were often attacked by sharks. In some cases, they had few weapons to protect themselves with. They found that just splashing(溅水) water seemed to help keep the sharks away.

One sailor was swimming for his life in the Atlantic Ocean after his boat had been blown up. He saw a shark swimming towards him. He hit the shark with his bare fist, and that drove it off.

Once, in Australia, a fisherman was fishing after sunset. He hooked a big fish and drew it towards the shore. His line broke when the fish was only a few yards from the shore. The fisherman waded(涉水) into the water to try to catch it with his hands. In the dim light, it looked like the kind of fish that could be dealt with without danger.

He put his arms around the fish and wrestled with it. Dragging it to the beach turned out to be harder than he had expected, but at last he pulled it in. When he turned a light on it, he was amazed. He had caught a shark. It was small for a shark, but it was the man-eating type and was about as long as a tall man.In a word, the best way to deal with sharks is to keep far away from them.

60. The shark that is least dangerous to man is the ________.

A. white shark      B. whale shark   C. tiger shark     D. hammerhead shark

61. This story tells you that sharks are usually ________.

A. friendly         B. small         C. afraid of people     D. dangerous

62. After the Australian fisherman found he had caught a shark, he was _________.

A. surprised      B. frightened      C. unhappy      D. angry

63. This story tells you that the best way to handle sharks is to ________.

A. hit them with your fist                 B. keep far away from them

C. splash water                         D. wrestle with them

64. The passage mainly tells us something  ________.

A. about fishing sharks                  B. about sharks

C. how to eat  sharks                   D. that sharks are man’s enemies