Each metal or alloy possesses a certain distinct combination of properties which differs it from other metals and alloys and by which metals and alloys are determined for a given engineering application. This combination of properties may be varied by alloying with other elements.
Before starting to study the properties of metals and alloys we should get an idea of what the terms “pure metal” and “alloys” mean. The term “alloy” is commonly used to describe a metallic solid containing two or more metals and metalloids. The properties of an alloy are influenced by the properties of the elements it consists of. As a rule, alloys are defined by their dominant element which is present in a quantity over 50% (per cent) by weight, the remainder are alloying elements and impurities. There are a lot of alloys, for example, copper-base alloys, aluminium-base alloys and so on.
The term “pure metal” is used for materials from which almost all chemical elements but one are eliminated.
The designation “metal” is sometimes applied in metallurgy to any metallic materials without making any distinction between a pure metal and an alloy. The first definition of the word “metal” was formulated by M. V. Lomonosov in the following way: “A metal is a bright solid that can be forged”. This definition is still true. The metallic luster and the ability for plastic deformation are, in fact, looked upon as the characteristic features of metals. The most important feature of metals, however, is their high electrical conductivity which decreases as the temperature is raised.
In conclusion it’s necessary to mention that metals and alloys are the most important engineering materials due to their excellent properties.
10. Выпишите из текста 10 интернациональных слов и переведите их.
11. Выпишите из текста 5 существительных, 5 прилагательных и 4 наречия образованных с помощью словообразовательных суффиксов.
12. Выпишите из текста 3 словосочетания модальный глагол или его эквивалент + инфинитив.
13. Подчеркните в тексте 5 сказуемых в страдательном залоге.
14. Ответьте на следующие вопросы, опираясь на текст.
1. What new metals have recently come to light?
2. What does the term “alloy” mean?
3. What determines the properties of an alloy?
4. What does the term “pure metal” mean?
5. What is the most important feature of metals?
15. Выполните перевод текста.
Variant 6
1. Переведите интернациональные слова на русский язык. Значение выделенного слоова, уточните по словарю.
to inspect –
machine –
clay –
mechanism –
principle –
technological –
to regulate –
condenser –
conductor –
corrosion –
2. Проанализируйте слова с различными суффиксами и разделите их на четыре группы: существительные, прилагательные, глаголы, наречия. Выделите суффиксы и переведите
informal, broaden, education, different, experience, useful, language, simply, teacher, television, childhood, productive, regularly, qualify, special, physically, mentally, changeable, intelligent, specialist, pressurize, primarily, agriculture, pleasure, absolutely, public, independent, mainly, assistance, demonstrate.
Nouns - существительные | Adjectives - прилагательные | Verb глаголы | Adverbs наречия |
3. Переведите предложения, обращая внимание на многозначность выделенного слова.
1. The power of this generator is equal to n5 W.
2. Eight is the third power of two.
3. They took power over several provinces.
4. The solution of the puzzle is on page 26.
5. The density of this solution is very high.
4. Определите, какими частями речи являются выделенные слова, принимая во внимание их место в предложении и формальные признаки. Предложения переведите.
1. Our professor always answer ( ) all our questions.
2. At the age of 70 Einstein still looked for the answers ( ) to new secrets of time and space.
3. The lathe can cut and form ( ) metal parts.
4. The form ( ) of this part is absolutely new.
5. The new hydroelectric station supplies ( ) energy to many industrial centres.
6. The supplies ( ) of electrical energy in our country are very great.
5. Переведите предложения, обращая внимание на глаголы с послелогами.
1. He was in bed for a month, but he is getting about again.
2. How is he getting along with his work?
3. We must get at the truth.
4. When shall I get my book back?
5. Get down the books from the shelf, please.
6. I have left the key and couldn't get in.
7. I'm getting off the bus at the last stop.
6. Переведите сочетания слов, обращая внимание на перевод существительных в функции определения
1. power transmission lines -
2. city water-supply system -
3. radio equipment -
4. an office clerk -
5. fuel energy consumption -
6. diesel engine -
7. wage rise -
8. data transmission network -
9. reference document -
10. metals transformation –
7. Подчеркните в предложениях сказуемое, содержащее модальный глагол или его эквивалент и переведите предложения на русский язык.
1. The distance between the Earth and the Moon may change.
2. Man had to create new sources of energy.
3. The workers were to assemble the machine yesterday.
4. The engineer has to use new technological processes.
5. At present man is able to solve many scientific problems by means of computers.
6. All these machines should be protected from corrosion.
8. Подчеркните в предложениях глагол-сказуемое, определите его видовременную форму и залог. Предложения переведите.
1. He has worked hard this week.
2. The new design was being studied by this engineer the whole day yesterday.
3. The builders will have constructed a twelve-storey house for the workers by the end of the year.
4. The worker was sent to the head engineer.
5. When the student entered the hall, professor had already been speaking for ten minutes.
6. The first scientific researches were followed by the experimental work.
7. The chemistry industry has been developing more speedily than other branches of industry.
8. The turbine are driven by the kinetic energy of the water.
9. The discovery of radio waves by Alexander Popov in 1895vhad a great value for mankind.
10. The electron was discovered more than fifty years ago, but has never been seen.
9. Прочитайте текст и выполните следующие за ним задания.
Metals in the Service of Man
Let us consider why metals play such a great role in man’s activities. Wood and stone are both older in use, yet to a considerable extent they have been replaced by metals. In spite of the great progress of chemistry and increasing output of plastic materials metals are still used for most of machines, structures and instruments. If there were no metals, no railway, airplane, car, electric motor, turbine or pipeline could operate.
The reason for the increased use of metals is to be found in their characteristic properties. The most important of these properties is their strength or ability to support weight without bending or breaking. Resistance to atmospheric destruction, plasticity and the ability to be formed into desired shapes are remarkable as well. Some metals have also special properties – two of which are the ability to conduct electric current and the ability to be magnetized.
Nowadays we know that over three quarters of existing elements are metals. We know approximately over 80 metals and several thousand alloys.
Most metals are usually found in nature as minerals or ores, where they exist in chemical combinations with other substances. Metallic ores contain metals combined with oxygen, sulphur or other metals.
Ores are usually mined and passed to the metallurgist for refining and purification. The ores are treated by fire or chemically by the process called smelting. Ores have to pass through this very complicated process before pure metals are obtained.
But pure metals are comparatively seldom used because they are rather expensive and their strength is generally insufficient for the purposes of to-day. The most important way in which the strength of metals can be increased is alloying. Alloys are the most important engineering materials. Alloys are obtained by adding various metals or non-metals to the main metallic element.
10. Выпишите из текста 10 интернациональных слов и переведите их.
11. Выпишите из текста 5 существительных, 5 прилагательных и 5 наречий образованных с помощью словообразовательных суффиксов.
12. Выпишите из текста 3 словосочетания модальный глагол или его эквивалент + инфинитив.
13. Подчеркните в тексте 5 сказуемых в страдательном залоге.
14. Ответьте на следующие вопросы, опираясь на текст.
1. What are the oldest structural materials?
2. In what forms do metals exist in nature?
3. Why are pure metals comparatively seldom used in industry?
4. What are the most important engineering materials?
5. How are alloys obtained?
15. Выполните перевод текста.
Variant 7
1. Переведите интернациональные слова на русский язык. Значение выделенного слова, уточните по словарю.
specialist –
automobile –
production –
phase –
accurate –
comfortable –
ecological –
method –
optimal –
mechanism –
2. Проанализируйте слова с различными суффиксами и разделите их на четыре группы: существительные, прилагательные, глаголы, наречия. Выделите суффиксы и переведите
|
Из за большого объема этот материал размещен на нескольких страницах:
1 2 3 4 5 6 7 8 9 10 11 12 |
