充值vip 上传试卷赚钱
快速导航
学历类
职业资格
公务员
医卫类
建筑工程
外语类
外贸类
计算机类
财会类
技能鉴定
特种作业
安全生产
医疗药物
交通相关
科技类
食品类
服务行业
健康护理
其他类
当前位置：考试网  > 试卷库  > 技能鉴定  > 其他类  > 石油石化职业技能鉴定  > 压风机司机  > 什么是压缩机？
试题预览

什么是压缩机？

查看答案
收藏
纠错
正确答案：

压缩机是一种压缩气体提高气体压力或输送气体的机器，叫压缩机又叫压气机和压风机、各种压缩机都属于动力机械，能将气体体积缩小，压力增高，具有一定的动能，可作为机械动力或其他用途。根据所压缩的气体不同，称空气压缩机，氧气压缩机、氨压缩机、天然气压缩机等等。

答案解析：

暂无解析

上一题 下一题
你可能感兴趣的试题

下列选项中，属于工会基本职责的是()

查看答案

下列关于个人独资企业特点的表述，正确的有()

查看答案

下列情形中用人单位解除劳动合同，无须提前30天以书面形式通知劳动者本人，也不存在经济补偿的有（）

查看答案

简述无效合同的种类。

查看答案

领导者发扬良好学风的要求是（）

查看答案
热门试题 更多>
Managers know that stress is a barrier to motivating the workforce.
试题分类： 初级(口语)
练习次数：0次
Rubber protector
试题分类： 初级(口语)
练习次数：0次
Perks and Fitness: No Longer a Nicety but a Necessity
试题分类： 初级(口语)
练习次数：0次
In most cities and towns, the high volumes of road traffic become a problem. What are the causes of that and what actions could be taken to solve the problem?
试题分类： 写作
练习次数：0次
数据库应用系统功能设计包括哪两个方面?每个方面主要由哪些设计步骤组成?
试题分类： 计算机四级
练习次数：0次
I hoped we can cooperate happily.
试题分类： 口语
练习次数：0次
根据《国际货物销售合同公约》的规定，什么样的情况可造成发盘的失效?
试题分类： 理论与实务
练习次数：2次
1.The failure of a high-profile cholesterol drug has thrown a spotlight on the complicated machinery that regulates cholesterol levels.But many researchers remain confident that drugs to boost levels of 'good' cholesterol are still one of the most promising means to combat spiralling heart disease. 2.Drug company Pfizer announced on 2 December that it was cancelling all clinical trials of torcetrapib，a drug designed to raise heart-protective high-density lipoproteins (HDLs).In a trial of 15000 patients，a safety board found that more people died or suffered cardiovascular problems after taking the drug plus a cholesterol-lowering statin than those in a control group who took the statin alone. 3.The news came as a kick in the teeth to many cardiologists because earlier tests in animals and people suggested it would lower rates of cardiovascular disease."There have been no red flags to my knowledge," says John Chapman，a specialist in lipoproteins and atherosclerosis at the National Institute for Health and Medical Research (INSERM) in Paris who has also studied torcetrapib."This cancellation came as a complete shock." 4.Torcetrapib is one of the most advanced of a new breed of drugs designed to raise levels of HDLs，which ferry cholesterol out of artery-clogging plaques to the liver for removal from the body.Specifically，torcetrapib blocks a protein called cholesterol ester transfer protein (CETP)，which normally transfers the cholesterol from high-density lipoproteins to low density，plaque-promoting ones.Statins，in contrast，mainly work by lowering the 'bad' low-density lipoproteins. Under pressure 5.Researchers are now trying to work out why and how the drug backfired，something that will not become clear until the clinical details are released by Pfizer.One hint lies in evidence from earlier trials that it slightly raises blood pressure in some patients.It was thought that this mild problem would be offset by the heart benefits of the drug.But it is possible that it actually proved fatal in some patients who already suffered high blood pressure.If blood pressure is the explanation，it would actually be good news for drug developers because it suggests that the problems are specific to this compound.Other prototype drugs that are being developed to block CETP work in a slightly different way and might not suffer the same downfall. 6.But it is also possible that the whole idea of blocking CETP is flawed，says Moti Kashyap，who directs atherosclerosis research at the VA Medical Center in Long Beach，California.When HDLs excrete cholesterol in the liver，they actually rely on LDLs for part of this process.So inhibiting CETP，which prevents the transfer of cholesterol from HDL to LDL，might actually cause an abnormal and irreversible accumulation of cholesterol in the body."You're blocking a physiologic mechanism to eliminate cholesterol and effectively constipating the pathway," says Kashyap.Going up 7.Most researchers remain confident that elevating high density lipoproteins levels by one means or another is one of the best routes for helping heart disease patients.But HDLs are complex and not entirely understood.One approved drug，called niacin，is known to both raise HDL and reduce cardiovascular risk but also causes an unpleasant sensation of heat and tingling.Researchers are exploring whether they can bypass this side effect and whether niacin can lower disease risk more than statins alone.Scientists are also working on several other means to bump up high-density lipoproteins by，for example，introducing synthetic HDLs."The only thing we know is dead in the water is torcetrapib，not the whole idea of raising HDL," says Michael Miller，director of preventive cardiology at the University of Maryland Medical Center，Baltimore. Questions 7-13 Match torcetrapib，HDLs，statin and CETP with their functions (Questions 8-13)..Write the correct letter A，B，C or D in boxes 8-13 on your answer sheet.NB You may use any letter more than once. 7.It has been administered to over 10,000 subjects in a clinical trial. 8.It could help rid human body of cholesterol. 9.Researchers are yet to find more about it. 10.It was used to reduce the level of cholesterol. 11.According to Kashyap，it might lead to unwanted result if it's blocked. 12.It produced contradictory results in different trials. 13.It could inhibit LDLs.List of choices A.TorcetrapicB.HDLSC.StatinD.CETP
试题分类： 阅读
练习次数：3次
How shops can exploit people's herd mentality to increase sales 1.A TRIP to the supermarket may not seem like an exercise in psychological warfare—but it is.Shopkeepers know that filling a store with the aroma of freshly baked bread makes people feel hungry and persuades them to buy more food than they had intended.Stocking the most expensive products at eye level makes them sell faster than cheaper but less visible competitors.Now researchers are investigating how “swarm intelligence” (that is，how ants，bees or any social animal，including humans，behave in a crowd) can be used to influence what people buy. 2.At a recent conference on the simulation of adaptive behaviour in Rome，Zeeshan-ul-hassan Usmani，a computer scientist from the Florida Institute of Technology，described a new way to increase impulse buying using this phenomenon.Supermarkets already encourage shoppers to buy things they did not realise they wanted: for instance，by placing everyday items such as milk and eggs at the back of the store，forcing shoppers to walk past other tempting goods to reach them.Mr Usmani and Ronaldo Menezes，also of the Florida Institute of Technology，set out to enhance this tendency to buy more by playing on the herd instinct.The idea is that，if a certain product is seen to be popular，shoppers are likely to choose it too.The challenge is to keep customers informed about what others are buying. 3.Enter smart-cart technology.In Mr Usmani's supermarket every product has a radio frequency identification tag，a sort of barcode that uses radio waves to transmit information，and every trolley has a scanner that reads this information and relays it to a central computer.As a customer walks past a shelf of goods，a screen on the shelf tells him how many people currently in the shop have chosen that particular product.If the number is high，he is more likely to select it too. 4.Mr Usmani's “swarm-moves” model appeals to supermarkets because it increases sales without the need to give people discounts.And it gives shoppers the satisfaction of knowing that they bought the “right” product—that is，the one everyone else bought.The model has not yet been tested widely in the real world，mainly because radio frequency identification technology is new and has only been installed experimentally in some supermarkets.But Mr Usmani says that both Wal-Mart in America and Tesco in Britain are interested in his work，and testing will get under way in the spring. 5.Another recent study on the power of social influence indicates that sales could，indeed，be boosted in this way.Matthew Salganik of Columbia University in New York and his colleagues have described creating an artificial music market in which some 14,000 people downloaded previously unknown songs.The researchers found that when people could see the songs ranked by how many times they had been downloaded，they followed the crowd.When the songs were not ordered by rank，but the number of times they had been downloaded was displayed，the effect of social influence was still there but was less pronounced.People thus follow the herd when it is easy for them to do so. 6.In Japan a chain of convenience shops called RanKing RanQueen has been ordering its products according to sales data from department stores and research companies.The shops sell only the most popular items in each product category，and the rankings are updated weekly.Icosystem，a company in Cambridge，Massachusetts，also aims to exploit knowledge of social networking to improve sales. 7.And the psychology that works in physical stores is just as potent on the internet.Online retailers such as Amazon are adept at telling shoppers which products are popular with like-minded consumers.Even in the privacy of your home，you can still be part of the swarm. Questions 1-6 Complete the sentences below with words taken from the reading passage.Use NO MORE THAN THREE WORDS for each answer. 1.Shopowners realize that the smell of _______________ can increase sales of food products. 2.In shops，products shelved at a more visible level sell better even if they are more _______________. 3.According to Mr.Usmani，with the use of “swarm intelligence” phenomenon，a new method can be applied to encourage _______________. 4.On the way to everyday items at the back of the store，shoppers might be tempted to buy _______________. 5.If the number of buyers shown on the _______________ is high，other customers tend to follow them. 6.Using the “swarm-moves” model，shopowners do not have to give customers _______________ to increase sales.
试题分类： 阅读
练习次数：52次
An increasing number of museums tend to charge admission fees from tourists rather than providing service free of charge. Do you think the advantages outweigh the disadvantages?
试题分类： 写作
练习次数：0次
相关题库 更多>
采油工 采气工 仪表工 供水调度工 压风机司机 电焊工 井下作业工 输气工 集输工 加油站操作员 变电站值班员 汽车驾驶员技师 汽车驾驶员(高级) 汽车驾驶员(中级) 汽车驾驶员(初级)
新手指南
会员服务
服务支持
扫一扫，手机做题