海船船员考试

单选题Many cast iron pistons are designed with heat dams, which serve to ()A keep piston crown temperatures elevated for smoother combustionB reduce the possibility of overheating the top compression ringC help retain the heat of compression to prevent ignit

题目
单选题
Many cast iron pistons are designed with heat dams, which serve to ()
A

keep piston crown temperatures elevated for smoother combustion

B

reduce the possibility of overheating the top compression ring

C

help retain the heat of compression to prevent ignition delay

D

help retain the heat of compression to prevent combustion knock

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相似问题和答案

第1题:

Eat as many vegetables as possible,for they are rich__iron.

A.of
B.in
C.with
D.for

答案:B
解析:
be rich in意为“富含……,在……(方面)富有,是固定搭配。

第2题:

Which statements concerning casting and conversion are true?()  

  • A、Conversion from int to long does not need a cast.
  • B、Conversion from byte to short does not need a cast.
  • C、Conversion from float to long does not need a cast.
  • D、Conversion from short to char does not need a cast.
  • E、Conversion from boolean to int using a cast is not possible.

正确答案:A,B,E

第3题:

共用题干
第三篇

Iron Deficiencies

Experts have observed for years that endurance athletes,particularly females,frequently have iron deficiencies.Now a new study by a team of Purdue University researchers suggests that even moderate exercise may lead to reduced iron in the blood of women.
"We found that women who were normally inactive and then started a program of moderate exercise showed evidence of iron loss,"says Roseanne M.Lyle,associate professor at Purdue.Her study of 62 formerly inactive women who began exercising three times a week for six months was published in the journal Medicine & Science in Sports & Exercise."Women who consumed additional meat or took iron supplements were able to bounce back,"she notes."But the new exercisers who followed their normal diet showed a significant decrease in iron levels."
Iron deficiency is very common among women in general,affecting one in four female teenagers and one in five women aged 18 to 45,respectively.But the ratio is even greater among active women,affecting up to 80 percent of female endurance athletes.This means,Lyle says,that"too many women ignore the amount of iron they take in."
Women of childbearing age are at greatest risk,since their monthly bleeding is a major source of iron loss.Plus,many health-conscious women increase their risk by rejecting red meat,which contains the most easily absorbed form of iron.And because women often restrict their diet in an effort to control weight,they may not consume enough iron-rich food,and are liable to experience a deficiency.
"The average woman takes in only two thirds of the recommended daily allowance of iron," notes another expert."For a woman who already has a poor iron status,any additional iron loss from exercise may be enough to tip her over the edge into a more serious deficiency,"notes the expert. Exercise can result in iron loss through a variety of mechanisms.Some iron is lost in sweat,and,for unknown reasons,intense endurance exercise is sometimes associated with bleeding of the digestive system.
The best sources of iron,and the only sources of the form of iron most readily absorbed by the body,are meat,chicken,and fish.Good sources of other forms of iron include dates,beans,and some leafy green vegetables.

Who will have a significant decrease in iron levels?
A:All the women.
B:All the inactive women.
C:Women who start to do moderate exercise and follow their normal diet.
D:Women who start to do moderate exercise and consume additional meat or take iron supplements.

答案:C
解析:
文章第一段第一句告诉我们endurance athletes会缺铁,它是指“耐力运动员”。选项A是指“跳高运动员”,选项B是指“举重运动员”,选项C是指“马拉松运动员”,选项D是指“短跑运动员”。因此选项C最合适。
文章第二段第一句话提到“那些通常不运动的女性一旦开始适度的锻炼,就会出现铁含量下降的迹象”。因此只有选项D最正确。
文章第二段最后一句话提到,那些增食肉类食品或服用铁质补剂的女性能够恢复到健康状态。但突然参加锻炼却仍沿用旧食谱的人则显示出铁含量降低。因此只有选项D正确。
文章第三段第一句话告诉我们,每四个十几岁的少女中有一人缺铁,每五个18岁至45岁的女性中有一人缺铁。而在积极锻炼的妇女中这一比例更高,女耐力运动员中,缺铁者比例则高达80%。因此只有选项C表述正确。
文章第四段告诉我们选项A、B、D所指人群都有缺铁的风险,第六段提示我们富含铁的食物中提到了bean和date,因此只有C项是正确的。

第4题:

单选题
The possibility of damage from operating a diesel engine at critical speeds is reduced by the use of().
A

an isochronous governor

B

elastic engine mounts

C

a vibration damper

D

a cast iron bed plate with good flexible qualities


正确答案: C
解析: 暂无解析

第5题:

单选题
The cast iron was melted and _____ into sand molds as soon as possible.
A

regulated

B

relayed

C

poured

D

oppressed


正确答案: D
解析:
句意:铸铁被熔化,然后尽快到进沙砾做的模子里。pour倾泻,倾倒。regulate控制。调整。relay分程传送。转播。oppress压迫,压抑。

第6题:


According to Paragraph 5,the EEOB’s decoration details( )

A.had almost no cast iron and plaster
B.hardly use of wood for fireproofing
C.are with the materials of granite,bronze,and glass
D.are with carved wood,oriental rugs,and stenciled wall patterns

答案:C
解析:

第7题:

When comparing capacity-to-capacity, the IBM Rear Door Heat eXchanger helps provide more advantages than other available thermal environment solutions, usually at a fraction of the cost.   Which of the following statements is NOT an advantage of the IBM Rear Door Heat eXchanger? ()

  • A、The IBM Rear Door Heat eXchanger may dramatically unburden existing AC units by cooling the air before it exhausts from the electronics into the hot aisle.
  • B、The IBM Rear Door Heat eXchanger is a "hang, plug, and run" design so the units may be added quickly.
  • C、The IBM Rear Door Heat eXchanger is equipped with two fans to help maintain water temperature at 18C (64.4F) and provide even air flow.
  • D、The IBM Rear Door Heat eXchanger is designed to support a 42U rack.

正确答案:C

第8题:

共用题干
第三篇

Iron Deficiencies

Experts have observed for years that endurance athletes,particularly females,frequently have iron deficiencies.Now a new study by a team of Purdue University researchers suggests that even moderate exercise may lead to reduced iron in the blood of women.
"We found that women who were normally inactive and then started a program of moderate exercise showed evidence of iron loss,"says Roseanne M.Lyle,associate professor at Purdue.Her study of 62 formerly inactive women who began exercising three times a week for six months was published in the journal Medicine & Science in Sports & Exercise."Women who consumed additional meat or took iron supplements were able to bounce back,"she notes."But the new exercisers who followed their normal diet showed a significant decrease in iron levels."
Iron deficiency is very common among women in general,affecting one in four female teenagers and one in five women aged 18 to 45,respectively.But the ratio is even greater among active women,affecting up to 80 percent of female endurance athletes.This means,Lyle says,that"too many women ignore the amount of iron they take in."
Women of childbearing age are at greatest risk,since their monthly bleeding is a major source of iron loss.Plus,many health-conscious women increase their risk by rejecting red meat,which contains the most easily absorbed form of iron.And because women often restrict their diet in an effort to control weight,they may not consume enough iron-rich food,and are liable to experience a deficiency.
"The average woman takes in only two thirds of the recommended daily allowance of iron," notes another expert."For a woman who already has a poor iron status,any additional iron loss from exercise may be enough to tip her over the edge into a more serious deficiency,"notes the expert. Exercise can result in iron loss through a variety of mechanisms.Some iron is lost in sweat,and,for unknown reasons,intense endurance exercise is sometimes associated with bleeding of the digestive system.
The best sources of iron,and the only sources of the form of iron most readily absorbed by the body,are meat,chicken,and fish.Good sources of other forms of iron include dates,beans,and some leafy green vegetables.

Which group of women will possibly have iron loss?
A:one in four women aged 18 to 45.
B:one in five female teenagers.
C:80 percent of female endurance athletes.
D:80 percent of active women.

答案:C
解析:
文章第一段第一句告诉我们endurance athletes会缺铁,它是指“耐力运动员”。选项A是指“跳高运动员”,选项B是指“举重运动员”,选项C是指“马拉松运动员”,选项D是指“短跑运动员”。因此选项C最合适。
文章第二段第一句话提到“那些通常不运动的女性一旦开始适度的锻炼,就会出现铁含量下降的迹象”。因此只有选项D最正确。
文章第二段最后一句话提到,那些增食肉类食品或服用铁质补剂的女性能够恢复到健康状态。但突然参加锻炼却仍沿用旧食谱的人则显示出铁含量降低。因此只有选项D正确。
文章第三段第一句话告诉我们,每四个十几岁的少女中有一人缺铁,每五个18岁至45岁的女性中有一人缺铁。而在积极锻炼的妇女中这一比例更高,女耐力运动员中,缺铁者比例则高达80%。因此只有选项C表述正确。
文章第四段告诉我们选项A、B、D所指人群都有缺铁的风险,第六段提示我们富含铁的食物中提到了bean和date,因此只有C项是正确的。

第9题:

单选题
An advantage of aluminum pistons, when compared to cast iron pistons is ().
A

greater high temperature strength

B

better heat conductivity

C

greater weight per cubic inch

D

increased resistance to wear


正确答案: A
解析: 暂无解析

第10题:

单选题
Aluminum pistons have () coefficient of thermal expansion compared with those of cast iron.
A

higher

B

lower

C

the same

D

none of the above


正确答案: A
解析: 暂无解析

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