用英文介绍青神县的地理位置

geological location

地理位置可分为：经纬位置和海陆位置和交通位置

geographic location of China

In general, directions of the east is at right, and the west at left while the north is up and the south down on a map.

以中国为例 China The People"s Republic of China is a socialism country with its own characteristics. It is one of the developing countries. China lies in the east of Asia. It has a number of neighboring countries. To the north, northeast and northwest are the Mongolia, Russia and Korea. To the south are Vietnam, Laos, Thailand and the Philippine. To the west and southwest are India, Burma, Bhutan, Nepal and Pakistan. To the east is Japan, which faces China across the East China Sea. China is a country with a vast territory. It has an area of over 9,600,000 square kilometers. It consists of 34 provinces, autonomous regions, and municipalities directly under the Central Covernment. Beijing, which is situated in the North China, is its capital. The People"s Republic of China is one of the largest countries in the world. Now it has a population of more than 1.2 billion, making up a quarter of the world population. 以下是汉字部分哈: ①中华人民共和国是一个有中国特色的社会主义国家。它是一个发展中国家。 ②中国位于亚洲的东部，有许多邻国。北面和东北面有蒙古，俄罗斯和朝鲜；南面有越南、老挝、泰国和菲律宾；西面和西南面有缅甸、印度、尼泊尔、不丹和巴基斯坦；东面有日本，与中国隔海相望。 ③中国幅员辽阔，有九百六十万平方千米。 ④它有34个省、直辖市和自治区。首都是北京，位于华北。 ⑤中国是世界上最大的国家之一。现在，它有12多亿人口，占世界人口的四分之一。

Compared to the United Kingdom, the United States, China"s geographical location is different

The United States of America locates in central and northwest North America with coastlines on the Atlantic and Pacific oceans.It includes the noncontiguous states of Alaska and Hawaii and various island territories in the Caribbean Sea and Pacific Ocean. 美国位于北美洲中部和西北,海岸线延及太平洋和大西洋.它包括非邻接的阿拉斯加州、夏威夷洲和在加勒比海、太平洋中的许多岛屿领土.

Located in the east of the Asia-Europe Continent, on the western shore of the Pacific Ocean, China has a land boundary of some 20,000 km, with 15 neighboring countries.　　China"s mainland coastline extends from the Yalu River on the border with North Korea in the north to the Beilun River on the border of China and Vietnam in the south, measuring approximately 18,000 km. The Chinese mainland is flanked to the east and south by the Bohai, Yellow, East China and South China seas. A total of over 5,000 islands dot China"s territorial waters. The largest of these is Taiwan. The island coastline measures approximately 14,000 km.　　China is bordered by Korea to the east; Mongolia to the north; Russia to the northeast; Kazakhstan, Kyrgyzstan and Tajikistan to the northwest; Afghanistan, Pakistan, India, Nepal, Sikkim and Bhutan to the west and southwest; and Vietnam, Laos and Myanmar to the south.　　Across the seas to the east and southeast of China are Japan, the Republic of Korea, the Philippines, Malaysia, Indonesia and Brunei.

Australia country in the Southern Hemisphere comprising the mainland of the Australian continent (the world"s smallest), the island of Tasmania and numerous smaller islands in the Indian and Pacific Oceans. Neighbouring countries include Indonesia, East Timor and Papua New Guinea to the north, the Solomon Islands.

Great Britain (Scottish Gaelic: Breatainn Mhòr, Welsh: Prydain Fawr) is the largest island of the British Isles, the largest island in Europe and the eighth-largest island in the world. It lies to the northwest of Continental Europe, with Ireland to the west, and makes up the largest part of the territory of the state known as the United Kingdom of Great Britain and Northern Ireland. It is surrounded by over 1,000[citation needed] smaller islands and islets.The historic nations of England, Scotland and the principality of Wales are mostly situated on the island, along with their capital cities, London, Edinburgh and Cardiff respectively.

美国位于北美洲南部，东临大西洋，西濒太平洋，北接加拿大，南靠墨西哥及墨西哥湾。美国国土面积占世界总面积的7％，居世界第四位。美国面积9372610平方公里（其中陆地面积915.8960万平方公里，内陆水域面积约20万平方公里），如果加上五大湖中美国主权部分约17万平方公里，河口、港湾、内海等沿海水域面积约10万平方公里，面积为963万平方公里，如果只计陆地面积，美国排名第三，仅次于俄罗斯、中国，在加拿大之前。扩展资料美国国土地形变化多端，地势西高东低。东海岸沿海地区有着海岸平原，南宽北窄，一直延伸到新泽西州，在长岛等地也有一些冰川沉积平原。在海岸平原后方的是地形起伏的山麓地带，延伸到位于北卡罗来纳州和新罕布什尔州、高1830米的阿巴拉契亚山脉为止。美国大部分地区属于大陆性气候，南部属亚热带气候。中北部平原温差很大，芝加哥1月平均气温-3℃，7月24℃；墨西哥湾沿岸1月平均气温11℃，7月28℃。

用in the southeast of China in表示"在……范围内”,还表示“在…之中”. 比如：Haikou lies in the south of China on表示“与……毗邻,接壤”,还有表示“在……之上”强调和表面接触, 比如：Canada lies on the north of America to表示方位,不接壤. 比如:Haikou lies to the south of Guangzhou 另外： at,in和on表示地点时的区别 1.at表示地点： （1）用于指较小的地方.如： I shall wait for you at the station. （2）用于门牌号码前.如： He lives at 115 Zhongshan Road. 2.in表示地点： （1）用于指较大的地方.如： He lives in Shanghai. （2）虽然是很小的地方,如果说话人住在那里,也可用in.商店、学校、机关等,若看作一个地点（point）用at,若看作一个场所（place）用in.如： I met him at the post-office. I"m now working in the post-office. 3.on表示地点,一般指与面或线接触,意为“在……上；在……旁”.如： The picture was hanging on the wall. New York is on the Hudson River.

Xi"an lies on the Guanzhong Plain in central China, on a flood plain created by the eight surrounding rivers and streams, most of which are too polluted to be used as sources of fresh water.The city has an average elevation of 400 metres (1,312 ft) above sea level and an annual precipitation of 550 millimetres (22 in). The urban area of Xi"an is located at 34°16′N 108°56′E / 34.267°N 108.933°E / 34.267; 108.933 The Wei River provides potable water to the city.The city borders the northern foot of the Qinling Mountains to the south, and the banks of the Wei River to the north. Hua Shan, one of the five sacred Taoist mountains, is located 100 km away to the east of the city.At the beginning of Han Dynasty, Prime Minister Zhang Liang advised the emperor Liu Bang to choose Guanzhong as the capital of the Han Dynasty: "Guanzhong Plain, which is located behind Xiao Pass and Hangu Pass, connects Long Plain and Shu Plain. Land of thousands miles and rich in harvest can be found here, as if this place is belongs to the nation of the heaven." ("关中左崤函, 右陇蜀, 沃野千里, 此所谓金城千里, 天府之国也" 《史记·留侯世家》) Since then, Guanzhong is also known as "Nation of the Heaven".

oriental pearl 东方明珠

AF] AFRICA 非洲 [EU] EUROPE 欧洲 [AS] ASIA 亚洲 [OA] OCEANIA 大洋洲 [NA] NORTH AMERICA 北美洲 [SA] SOUTH AMERICA 南美洲 [AN] ANTARCTICA 南极洲

France is located in the Western Europe and lies between latitudes 48° 50" N, and longitudes 2° 20" E.

地理位置 United Kingdom, island country located off the northwestern coast of mainland Europe. The United Kingdom comprises the whole of the island of Great Britain—which contains England, Wales, and Scotland—as well as the northern portion of the island of Ireland.面积 The total area of the United Kingdom is approximately 244500 square kilometres.

the location of WuHan city in the map

ChinaThe People"s Republic of China is a socialism country with its own characteristics. It is one of the developing countries.China lies in the east of Asia. It has a number of neighboring countries. To the north, northeast and northwest are the Mongolia, Russia and Korea. To the south are Vietnam, Laos, Thailand and the Philippine. To the west and southwest are India, Burma, Bhutan, Nepal and Pakistan. To the east is Japan, which faces China across the East China Sea.China is a country with a vast territory. It has an area of over 9,600,000 square kilometers. It consists of 34 provinces, autonomous regions, and municipalities directly under the Central Covernment. Beijing, which is situated in the North China, is its capital.The People"s Republic of China is one of the largest countries in the world. Now it has a population of more than 1.2 billion, making up a quarter of the world population.以下是汉字部分哈:①中华人民共和国是一个有中国特色的社会主义国家。它是一个发展中国家。②中国位于亚洲的东部，有许多邻国。北面和东北面有蒙古，俄罗斯和朝鲜；南面有越南、老挝、泰国和菲律宾；西面和西南面有缅甸、印度、尼泊尔、不丹和巴基斯坦；东面有日本，与中国隔海相望。③中国幅员辽阔，有九百六十万平方千米。④它有34个省、直辖市和自治区。首都是北京，位于华北。⑤中国是世界上最大的国家之一。现在，它有12多亿人口，占世界人口的四分之一。

Australia is a country in the Southern Hemisphere comprising the mainland of the Australian continent (the world"s smallest),the island of Tasmania and numerous smaller islands in the Indian and Pacific Oceans.Neighbouring countries include Indonesia,East Timor and Papua New Guinea to the north,the Solomon Islands,Vanuatu and New Caledonia to the northeast and New Zealand to the southeast.

British mainland western Europe from Great Britain and Ireland, north-east and many nearby islands. The full name of the United Kingdom of Great Britain and Northern Ireland. She east by the North Sea, the Atlantic Ocean to the west, up to the North Atlantic off Iceland, Yugoslavia and the European continent, separated only by a strip of water, the English Channel. British total area of about 243,000 square kilometers. The main island is a British territory of Great Britain from northern Scotland. southwest of the southern and central parts of England and Wales, three regional groupings. England area of 130,000 square kilometers which, accounting for most of the island of Great Britain; Wales area of 20,000 square kilometers, territory is mountainous and rugged; Scottish area of 78,000 square kilometers. Northern Ireland area of 14,000 square kilometers. Britain is about 1,000 km from south to north and 50 ° north latitude and 61 ° C; Most things is not more than 500 km wide, east longitude 1 ° 45 "W 8 ° 10" between. Zero meridian through the southeast London GMT (Greenich). British coastline of about 11,500 km. Although the British high latitudes, but due to a single Atlantic, not the cold winter. British maritime climate temperate broadleaf forests. In normal years, the hottest (July), the average temperature of 19-25 degrees Celsius. the coldest (January), the average temperature of 4-7 degrees Celsius. British uneven rainfall throughout England low-lying, with an average rainfall of 830 mm, west, Mountain precipitation in the northern part of a larger, up to 4,000 mm. Britain is the main mineral resources of coal, iron, oil and gas. Hard coal reserves of 170 billion tons. Rail reserves of about 3.8 billion tons. In the United Kingdom North Sea continental shelf oil reserves of about 10-40 million tons. 8600-25,850 billion cubic meters of natural gas reserves in between. Britain"s total population of about 59 million, of which 50 million in England, Scotland, five million, three million in Wales. Northern Ireland 2 million. In the British capital of London, England.

以中国为例 China The People"s Republic of China is a socialism country with its own characteristics.It is one of the developing countries. China lies in the east of Asia.It has a number of neighboring countries.To the north,northeast and northwest are the Mongolia,Russia and Korea.To the south are Vietnam,Laos,Thailand and the Philippine.To the west and southwest are India,Burma,Bhutan,Nepal and Pakistan.To the east is Japan,which faces China across the East China Sea. China is a country with a vast territory.It has an area of over 9,600,000 square kilometers.It consists of 34 provinces,autonomous regions,and municipalities directly under the Central Covernment.Beijing,which is situated in the North China,is its capital. The People"s Republic of China is one of the largest countries in the world.Now it has a population of more than 1.2 billion,making up a quarter of the world population. 以下是汉字部分哈: ①中华人民共和国是一个有中国特色的社会主义国家.它是一个发展中国家. ②中国位于亚洲的东部,有许多邻国.北面和东北面有蒙古,俄罗斯和朝鲜；南面有越南、老挝、泰国和菲律宾；西面和西南面有缅甸、印度、尼泊尔、不丹和巴基斯坦；东面有日本,与中国隔海相望. ③中国幅员辽阔,有九百六十万平方千米. ④它有34个省、直辖市和自治区.首都是北京,位于华北. ⑤中国是世界上最大的国家之一.现在,它有12多亿人口,占世界人口的四分之一.

澳大利亚是大洋洲最大的国家,首都是堪培拉,但是主要城市还是悉尼,与新西兰隔海相望 Australia is the largest country in Oceania, the capital of Canberra, major cities of Sydney and New Zealand across the sea

位置的英文是position。position的读法为英音pu0259"zu026au0283n，美音pu0259"zu026au0283n。position作为名词时，最基本的含义是“位置”。它可以指物体或人所处的位置，也可以指某个地方的地理位置。例如：The position of the statue is right in front of the museum.这座雕像的位置就在博物馆前面。What"s the position of the company in the market。这家公司在市场上的地位上，position还可以指人的“姿势，姿态”，这是其比较形象的一个含义。例如：He sat in a chair in his favorite position.他坐在椅子上，摆出他最喜欢的姿势，position还可以指人对事物所持的“见解，态度”。这个含义比较抽象，但却是position比较重要的一个含义。例如：I take a positive position on the issue of gun control.我对枪支控制问题持积极态度。学习英语的好处：1、英语是全球通用语言在全球化日益加剧的今天，掌握英语能够更好地融入国际社会，更方便地与来自不同国家和文化的人交流和合作。也能更容易地与来自不同国家和文化的人建立联系和开展业务合作。2、学习英语可以开拓视野通过学习英语，可以了解西方世界的文化、历史、科学、技术等方面的知识，可以拓宽自己的知识面和视野，英语也是很多科学、技术的国际期刊和论文的书写语言，掌握了英语，就能更容易地了解和掌握这些领域的前沿动态。3、学习英语可以提高职业竞争力在求职和职业发展中，掌握英语往往是一个重要的优势。英语是很多行业的基本要求，掌握英语能够更好地在这些领域中发展自己的职业事业。掌握英语，就能更方便地与外籍同事和客户沟通，更好地完成工作任务。

搜一下：课题：大武汉。武汉的地理位置，要用英文写，越多越好，谢谢各位姐姐，哥哥。。

南京，地处我国东部沿海、长江下游地区。南京有很多古称，如金陵、建康、建业、江宁等，是我国八大古都之一，有近500年的建都史，东吴、东晋、南朝宋、齐、梁、陈先后在南京建都。南京之所以被戏称为“徽京”，有地理位置、历史、文化、经济等几个方面的原因。南京是国家重要的科教中心，自古以来就是一座崇文重教的城市，有“天下文枢”“东南第一学”之称，明清中国一半以上的状元均出自南京江南贡院。截至2020年，南京有各类高等院校68所，其中双一流高校13所、111计划高校10所，211高校8所、两院院士81人，均仅次于北京上海；全球科研城市20强排名，南京位列全球第8、中国第3。

Most of Harvard University is located in and near Cambridge,Boston,and Allston,Massachusetts,on the east coast of the United States of America.Harvard College and some graduate schools are located in Cambridge.The Harvard Business School and many athletic facilities are across the Charles River in Allston.The Harvard Medical School,the Harvard School of Public Health,the Harvard School of Dental Medicine,and many affiliated medical institutions are in an area of Boston known as the Longwood Medical Area or Longwood Medical Campus.

1、优越的地理位置predominant geographical position2、丰富独特的旅游资源plentiful unique tourist resources/ plentiful unique sightseeing resource3、催人奋进的奋斗目标inspiring striving goal4、多元化的立体交通网络 a wide range of steric traffic network5、强大的能源支撑 powerful support for energy6、必要性和可行性 necessity and feasibility7、建设规模及内容 construction scale and content 8、建设条件 condition construction9、市场预测 market forecasting10、项目效益分析 project-benefit analysis11、市场预测和效益分析 market forecasting and benefit analysis12、项目前期工作进展情况 the progress of the project of preliminary work

Tongjiang county belongs to the northeast of sichuan bazhong, MiCangShan eastern, south dabashan mountain gaps in 31 ° north latitude 39 "~ 32 ° 33", longitude 106 ° between "~ 107 ° 46" 59. Pingchang county wanyuan county east, south, west by bazhou, nanjiang county, shaanxi province in the north to south, xixiang, zheng town three counties. Tongjiang county 150 kilometers south from dazhou, 420 km away from chongqing. 89 kilometers west of bazhong, 580 km from provincial capital chengdu, 270 km away from in guangyuan city; East 180 kilometers away from wanyuan; The north is 158 km from zhenba county of shaanxi province. 131 kilometers northwest of nanjiang.

　　Guizhou Province is in the southwest part of the People"s Republice of China.The origin of the Zhujiang River is in the Mut Wumeng.There"re millions of mountains and people there arekind of poor but honest and hard-working. Guizhou Province is hot and rains a lot in the summur.But it is not cold and dry in the winter.

Guangzhou Travel Guide Guangzhou, the South Gate of China, is the capital city of Guangdong.It"s the center of its political, economic, scientific, educational and cultural life. The kapok is the city flower and the kapok tree is the city tree of Guangzhou. Guangzhou is located in the middle south of Guangdong Province, north of the Pearl River Delta. It lies close to the South China Sea, Hong Kong, and Macau. Zhujiang (The Pearl River), the third largest river of China, runs through Guangzhou and is navigable to the South China Sea. Situated in such an excellent geographical region, Guangzhou is called China"s South Gate. Covering an area of 7434.4 square kilometers,Guangzhou is home to more than 11 million people.(不好意思，字数我也不知对不对，看着删减吧）

1.south 2.north3.east4.north-westnorth-east

France is to the south of England.France is on the west of Switzerland.

Certainly one of the best spots in the Mediterranean , Barcelona is the capital city of Catalunya and is one of the 17 Autonomous Communities that make up Spain . It is strategically located in a very privileged position on the northeastern coast of the Iberian peninsula, along the Mediterranean coast, around 41 and 2 Its being located at the Mediterranean sea in the very north of the Spanish coast also contributes to making it certainly the most cosmopolitan and most economically active city in the country of Spain . Barcelona is 160 km (100 mi) south of the Pyrenees mountain range and is nestled in between the mouths of the rivers Llobregat and Bes , and the shores of the Mediterranean . It has an altitude of 4 m above sea level and has the following distances from: Tarragona (98 km), Girona (100 km), Lleida (156 km), Huesca (274 km), Castellon (284 km), Zaragoza (296 km) and Madrid (621 km).Located in the comarca of Barcelon , Barcelona is also the second largest city in Spain in both size and population. The city has a population of 1,510,000, but this number escalates to more than 4,000,000 if the outlying areas are also included in the count. As estimated as of year 2005, the population of the city proper is at 1,593,075, while the population of the metropolitan area is at 4,686,701. On the other hand, population of the province of Barcelona is 5,226,354 although this population only covers 7,733 km (3,000 mi around the city.

Jiangsu is a province of the People"s Republic of China, located along the east coast of the country.Jiangsu borders Shandong in the north, Anhui to the west, and Zhejiang and Shanghai to the south. Jiangsu has a coastline of over one thousand kilometers along the Yellow Sea, and the Yangtze River passes through its southern parts. Since the inception of economic reforms in 1978, Jiangsu has been a hot spot for economic development, and is now one of China"s most prosperous provinces.

哥们，这题选a，你是对的，我今天才做的这道题。给你拍一张照好了，，擦拍不了啊，算了给你讲吧。道理很简单，，假设这两个货都满偏，那么他们各自两端的电压都相等（g表），但是如果联1，他还有一个电阻在串联啊，所以与1联的时候每个支路上的电压都比联2时只路上的电压要大的。联1底下就一个电阻，而联2就有两个，所以。。。所以就选a了。。我怎么觉得我说得稀里糊涂的，，算了你不懂再问我

三相交流异步电动机工作原理：(1)当三相异步电机接入三相交流电源时，三相定子绕组流过三相对称电流产生的三相磁动势（定子旋转磁动势）并产生旋转磁场。(2)该旋转磁场与转子导体有相对切割运动,根据电磁感应原理,转子导体产生感应电动势并产生感应电流。（3）根据电磁力定律，载流的转子导体在磁场中受到电磁力作用，形成电磁转矩，驱动转子旋转，当电动机轴上带机械负载时，便向外输出机械能。电机的转速（转子转速）小于旋转磁场的转速，从而叫为异步电机。它和感应电机基本上是相同的。s=(ns-n)/ns。s为转差率，ns为磁场转速，n为转子转速。三相异步电动机的转速永远低于旋转磁场的同步转速，使转子和旋转磁场间有相对运动，从而保证转子的闭合导体切割磁力线，感生电流，产生转矩。转速的差异是异步电机运转的必要条件。在额定情况下，转子转速一般比同步转速低2-5%。

电缸应该是新名词，伺服缸吧，滑台只是导轨这样可以么？

你搞分子生物学的？在哪个洞混呢

一、反接制动： 在电机断开电源后，为了使电机迅速停车，使用控制方法再在电机的电源上加上与正常运行电源反相的电源，此时，电机转子的旋转方向与电机旋转磁场的旋转方向相反，此时电机产生的电磁力矩为制动力矩，加快电机的减速。如下图示，利用开关Q将电枢两端的电压从电网断开，并立即将它接到一个制动电阻RL上，这时，电机内的主磁场保持不变，电枢因由惯性继续转动此时的点此力矩为制动转矩，故使电机转速下降，直到停转。 反接制动有一个最大的缺点，就是：当电机转速为0时，如果不及时撤除反相后的电源，电机会反转。解决此问题的方法有以下两种：1、在电机反相电源的控制回路中，加入一个时间继电器，当反相制动一段时间后，断开反相后的电源，从而避免电机反转。但由于此种方法制动时间难于估算，因而制动效果并不精确。2、在电机反相电源的控制回路中加入一个速度继电器，当传感器检测到电机速度为0时，及时切掉电机的反相电源。由于此种方法速度继电器实时监测电机转速，因而制动效果较上一种方法要好的多。正是由于反接制动有此特点，因此，不允许反转的机械，如一些车床等，制动方法就不能采用反接制动了，而只能采用能耗制动或机械制动。二、能耗制动： 在定子绕组中通以直流电，从而产生一个固定不变的磁场。此时，转子按旋转方向切割磁力线，从而产生一个制动力矩。由于此制动方法并不是象再生制动那样，把制动时产生的能量回馈给电网，而是单靠电机把动能消耗掉，因此叫能耗制动。又由于是在定子绕组中通以直流电来制动，因而能耗制动又叫直流注入制动。如下图示，利用倒向开关开关Q把点数电压反接到电网，此时的电枢电流将变成复制，且电流大小相当，随之产生很大的制动性质的电机转矩，是电机停转。 能耗制动是单纯依靠电机来消耗动能来达到停车的目的，因而制动效果和精度并不理想。在一些要求制动时间短和制动效果好的场合，一般不使用此制动方法。如起重机械，其运行特点是电机转速低，频繁地起动、停止和正反转，而且拖着所吊重物运行。为了实现准确而又灵活的控制，电机经常处于制动状态，并且要求制动力矩大。而能耗制动则达不到上述要求。故起重机械一般采用反接制动，且要求有机械制动，以防在运行过程中或失电时，重物滑落。三、再生制动： 再生制动和上述两种制动方法均不同。再生制动只是电机在特殊情况下的一种工作状态，而上述两者是为达到迅速停车的目的，人为在电机上施加的一种方法。再生制动的原理：当电机的转子速度超过电机同步磁场的旋转速度时，转子绕组所产生的电磁转矩的旋转方向和转子的旋转方向相反，此时，电机处于制动状态。之所以把此时的状态叫再生制动，是因为此时电机处于发电状态，即电机的动能转化成了电能。此时，可以采取一定的措施把产生的电能回馈给电网。达到节能的目的。因此，再生制动也叫发电制动。再生制动会出现在以下两种场合：1、起重机重物下降时，电机转子在重物重力的手动下，转子的转速有可能超过同步转速，此时，电机处于再生制动状态。这时，电机的制动转矩是阻止重物的下落，直至制动转矩和重力形成的转矩相等时，重物才会停止下落。2、当变频调速时，当变频器把频率降低时，同步转速也随之降低。但转子转速由于负载惯性的作用，不会马上降低，此时，电机也会处于再生制动状态，直至拖动系统的速度也下降为止。

得到电子时为-1；不是，比如在氢化钠中就是-价2.没有，因为氢是还原性物质，只有在和金属性非常强的物质反应时才会显示出氧化性。

伺服电动缸，在SMC产品中，是伺服马达带动的夹爪类器件，动作类似于气动手指。实质上它已不在“缸”的范围，SMC做气动的缸多，估计他们因此把它也叫做“缸”了。以上，纯属个人谬论~

可逆是指四象限，一般用4Q表示。可控硅整流器可工作在整流区，也可逆变将电动机产生的电反馈回电网。实现快速制动。不可逆只能工作在整流区

滤布调压阀由一根感应棒和阀体组成，它的主要作用是在带式污泥脱水机上进行对脱水机的滤布进行纠偏（校正）作用，当机台上的滤布偏向机台的一侧时，滤布就会触碰到调压阀的感应棒，此时、调压阀就会给出信号到纠偏气缸，当纠偏气缸收到信号后，就会立即作出前进或后退的动.

某些金属具有很强的捕捉氢的能力，在一定的温度和压力条件下，这些金属能够大量“吸收”氢气，反应生成金属氢化物，同时放出热量。其后，将这些金属氢化物加热，它们又会分解，将储存在其中的氢释放出来。这些会“吸收”氢气的金属，称为储氢合金。储氢合金的储氢能力很强。单位体积储氢的密度，是相同温度、压力条件下气态氢的1000倍，也即相当于储存了1000个大气压的高压氢气。由于储氢合金都是固体，既不用储存高压氢气所需的大而笨重的钢瓶，又不需存放液态氢那样极低的温度条件，需要储氢时使合金与氢反应生成金属氢化物并放出热量，需要用氢时通过加热或减压使储存于其中的氢释放出来，如同蓄电池的充、放电，因此储氢合金不愧是一种极其简便易行的理想储氢方法。目前研究发展中的储氢合金，主要有钛系储氢合金、锆系储氢合金、铁系储氢合金及稀土系储氢合金。储氢合金不光有储氢的本领，而且还有将储氢过程中的化学能转换成机械能或热能的能量转换功能。储氢合金在吸氢时放热，在放氢时吸热，利用这种放热－吸热循环，可进行热的储存和传输，制造制冷或采暖设备。储氢合金还可以用于提纯和回收氢气，它可将氢气提纯到很高的纯度。例如，采用储氢合金，可以以很低的成本获得纯度高于99.9999%的超纯氢。储氢合金的飞速发展，给氢气的利用开辟了一条广阔的道路。

　　　　液压伺服阀结构及工作原理　　一、滑阀式伺服阀：　　采用动圈式力马达，结构简单，功率放大系数较大，滞环小和工作行程大；固定节流口尺寸大，不易被污物堵塞；主滑阀两端控制油压作用面积大，从而加大了驱动力，使滑阀不易卡死，工作可靠。　　喷嘴挡板式伺服阀：　　该伺服阀，由于力反馈的存在，使得力矩马达在其零点附近工作，即衔铁偏转角θ很小，故线性度好。此外，改变反馈弹簧杆11的刚度，就能在相同输入电流时改变滑阀的位移。该伺服阀结构紧凑，外形尺寸小，响应快。但喷嘴挡板的工作间隙较小，对油液的清洁度要求较高。　　射流管式伺服阀：　　对油液的清洁度要求较低。缺点是零位泄漏量大；受油液粘度变化影响显著，低温特差；力矩马达带动射流管，负载惯量大，响应速度低于喷嘴挡板阀。　　滑阀式伺服阀　　由永磁动圈式力马达、一对固定节流孔、预开口双边滑阀式前置液压放大器和三通滑阀式功率级组成。前置控制滑阀的两个预开口节流控制边与两个固定节流孔组成一个液压桥路。滑阀副的阀心（控制阀芯）直接与力马达的动圈骨架相连，（控制阀芯）在阀套内滑动。前置级的阀套又是功率级滑阀放大器的阀心。输入控制电流使力马达动圈产生的电磁力与对中弹簧的弹簧力相平衡，使动圈和前置级（控制级）阀心（控制阀芯）移动，其移量与动圈电流成正比。前置级阀心（控制阀芯）若向右移动，则滑阀右腔控制口·面积增大，右腔控制压力降低；左侧控制口·面积减小，左腔控制压力升高。该压力差作用在功率级滑阀阀心（即前置级的阀套）的两端上，使功率级滑阀阀心（主滑阀）向右移动，也就是前置级滑阀的阀套（主滑阀）向右移动，逐渐减小右侧控制孔的面积，直至停留在某位置。在此位置上，前置级滑阀副的两个可变节流控制孔的面积相等，功率级滑阀阀心（主滑阀）两端的压力相等。这种直接反馈的作用，使功率级滑阀阀心跟随前置级滑阀阀心运动，功率级滑阀阀心的位移与动圈输入电流大小成正比。　　滑阀式伺服阀　　由永磁动圈式力马达、一对固定节流孔、预开口双边滑阀式前置液压放大器和三通滑阀式功率级组成。前置控制滑阀的两个预开口节流控制边与两个固定节流孔组成一个液压路。滑阀副的阀心（控制阀芯）直接与力马达的动圈骨架相连，（控制阀芯）在阀套内滑动。前置级的阀套又是功率级滑阀放大器的阀心。　　输入控制电流使力马达动圈产生的电磁力与对中弹簧的弹簧力相平衡，使动圈和前置级（控制级）阀心（控制阀芯）移动，其位移量与动圈电流成正比。前置级阀心（控阀芯）若向右移动，则滑阀右腔控制口·面积增大，右腔控制压力降低；左侧控制口面积减小，左腔控制压力升高。该压力差作用在功率级滑阀阀心（即前置级的阀套）的两端上，使功率级滑阀阀心主滑阀）向右移动，也就是前置级滑阀的阀套（主滑阀）向右移动，逐渐减小右侧控制孔的面积，直至停留在某一位置。在此位置上，前置级滑阀副的两个可变节流制孔的面积相等，功率级滑阀阀心（主滑阀）两端的压力相等。这种直接反馈的作用，使率级滑阀阀心跟随前置级滑阀阀心运动，功率级滑阀阀心的位移与动圈输入电流大小成比。

1、细胞毒性是由细胞或者化学物质引起的单纯的细胞杀伤事件，不依赖于凋亡或坏死的细胞死亡机理。有时需要进行特定物质细胞毒性的检测，比如药物筛选。 2、细胞毒性检测主要是根据细胞膜通透性发生改变来进行的检测，常用以下几种方法。 3、MTT、XTT法：利用线粒体内部酶的活性，可以将特定的四唑盐类进行转化，然后通过酶标仪进行检测。 4、LDH的方法：通过检测细胞培养上清中LDH的酶活性，来检测细胞毒性。 5、其它酶方法：如检测上清中碱性磷酸酶、酸性磷酸酶的活性等。

细胞活性测定方法有台盼蓝染色法、克隆（集落）形成法、 3H 放射性同位素掺入法、 MTT 法等。其中 MTT 法以其快速简便，不需要特殊检测仪器、无放射性同位素、适合大批量检测的特点而得到广泛的应用。但 MTT 法形成的 Formazan 为水不溶性的，需要加有机溶剂溶解，由于在去上清操作时会有可能带走小部分的 Formazan ，故有时重复性略差。为了解决这个问题，研究人员又开发了很多种水溶性的四氮唑盐类：如 XTT 、 CCK-8 （ WST-8 ）等。

游离态不是化合物

过滤调压阀是用来做什么的减压的气动阀门定位器是按力平衡原理设计工作的，其工作原理方框见上图所示，它是按力平衡原理设计和工作的。如图上图所示当通入波纹管的信号压力增加时，使杠杆2绕支点转动，档板靠近喷嘴，喷嘴背压经放大器放大后，送入薄膜执行机构气室，使阀杆向下移动，并带动反馈杆（摆杆）绕支点转动，连接在同一轴上的反馈凸轮（偏心凸轮）也跟着作逆时针方向转动，通过滚轮使杠杆1绕支点转动，并将反馈弹簧拉伸、弹簧对杠杆2的拉力与信号压力作用在波纹管上的力达到力矩平衡时仪表达到平衡状态。此时，一定的信号压力就与一定的阀门位置相对应。以上作用方式为正作用，若要改变作用方式，只要将凸轮翻转，A向变成B向等，即可。所谓正作用定位器，就是信号压力增加，输出压力亦增加；所谓反作用定位器，就是信号压力增加，输出压力则减少。一台正作用执行机构只要装上反作用定位器，就能实现反作用执行机构的动作；相反，一台反作用执行机构只要装上反作用定位器，就能实现正作用执行机构的动作。 相关网站（附图） 调节阀通常由电动执行机构或气动执行机构与阀体两部分共同组成。直行程主要有直通单座式和直通双座式两种，后者具有流通能力大、不平衡办小和操作稳定的特点，所以通常特别适用于大流量、高压降和泄漏少的场合。角行程主要有：V型电动调节球阀、电动蝶阀、通风调节阀、偏心蝶阀等。