44721

Gerund (forms and functions)

Конспект урока

Иностранные языки, филология и лингвистика

Prctise reding the following twosyllble words with the stress on the second syllble: Include between employ pply design convert trnsform obtin Prctise reding the following mny syllble words: Electricity impossible ccumulte numerous resistnce temperture emergency photocell complicted Prctise reding the following words with double stress: Engineering semiconductor utomtion conductivity irrespective reproduce Memorize the spelling nd pronuncition of the following words: Vry ['vεərI]...

Английский

2013-11-13

114.28 KB

5 чел.

6

UNIT 9

Grammar: Gerund (forms and functions)

Reading Exercises.

  1.  Practise reading the following one-syllable words:

    Sun, cold, light, ore, part, fall, switch, kind, turn, way, half, few, term, cent, branch.

  1.  Practise reading the following two-syllable words with the stress on the first syllable:

    Metal, sharply, prospect, system, constant, progress, fraction, power, cover, sunlight.

  1.  Practise  reading the following two-syllable words with the stress on the second syllable:

    Include, between, employ, apply, design, convert, transform, obtain

  1.  Practise reading the following many syllable words:

    Electricity, impossible, accumulate, numerous, resistance, temperature, emergency, photocell, complicated

  1.  Practise reading the following words with double stress:

    Engineering, semiconductor, automation, conductivity, irrespective, reproduce

  1.  Memorize the spelling and pronunciation of the following words:

    Vary ['ərI] –міняти, змінювати

Variety [vəraIətI] –різноманітність

    Technique [tek'ni:k] –метод

    Design [dI'zaIn] –проект

    Circuit ['sə:kIt] –схема

    Determine [dI'tə:mIn] –визначати

Text 9 A

SEMICONDUCTORS

The term “semiconductor” means “half-conductor”, that is, a material whose conductivity ranges between that of conductors and non-conductors or insulators.

They include a great variety of elements (silicon, germanium, selenium, phosphorus and others), many chemical compounds (oxides, sulphides) as well as numerous ores and minerals.

While the conductivity of metals is very little influenced by temperature, the conductivity of semiconductors sharply increases with heating and falls with cooling. This dependence has opened great prospects for employing semiconductors in measuring techniques.

Light as well as heat increases the conductivity of semiconducting materials, this principle is used in creating photo resistances. It is also widely applied for switching on engines, for counting parts on a conveyer belt, as well as for various systems of emergency signals and for reproducing sound in a cinematography. Besides reacting to light, semiconductors react to all kinds of radiations and are therefore employed in designing electronic counters.

Engineers and physicists turned their attention to semiconductors many years ago, seeing in them the way of solving complicated engineering problems. Converting heat into electricity without using boilers or other machines was one of them. This could be done by means of metal thermocouples, but in this way it was impossible to convert more than a few tenths of one per cent of the heat into electricity. The thermocouples made later of semiconductors generated ten times as much electricity as the metal ones.

Sunlight like heat can feed our electric circuits. Photocells made of semi-conducting materials are capable  of transforming ten per cent of sun-ray energy into electric power. By burning wood which has accumulated the same amount of solar energy, we obtain only fractions of one per cent of electric power.

The electricity generated by semiconductor thermocouples can produce not only heat but also cold, this principle is used in manufacturing refrigerators.

Semiconducting materials are also excellent means of maintaining a constant temperature irrespective of the surrounding temperature changes. The latter can vary over a wide range, for example, from 50° below 0° to 100° above 0°.

Notes:

  1.  emergency signals –аварийні сигнали
  2.  to turn one’s attention to –звернути свою увагу

Answer the questions:

  1.  What does the term “semiconductor” mean?
  2.  What elements do they include?
  3.  When does the conductivity of semiconductors sharply increase and fall?
  4.  What principle is used in creating photoresistances?
  5.  Where is it also widely applied?
  6.  Why are semiconductors employed in designing electronic counters?
  7.  Why did engineers and physicists turn their attention to semiconductors?
  8.  What principle has been used in manufacturing refrigerators?
  9.  What temperature can semiconducting materials maintain irrespective of the surrounding temperature changes?

Exercises

  1.  Translate the following words and state their parts of speech:

    Chemical, dependence, numerous, sharply, radiation, electronic, physicist,  possible, electricity, widely,  emergency

  1.  Translate the following words paying attention to the prefixes “ir-”, “re-” and “im-”:
  2.  Irrespective, irrational, irregular, irresponsible, irrecognizable;
  3.  Reproduce, rebuild, rewrite,  remove, restart, reappear, rewind, renew, repatriate, re-examination;
  4.  Impossible, impassable, imperfect, impenetrable, improbable, immeasurable,  immovable, impracticable
  5.  Form nouns after the models and translate them: V + ment, V + ion (tion), V+ ance (ence).

    Radiate, depend, produce, measure, differ, react, employ, automate, generate, develop, perform

  1.  Form adjectives adding the suffixes  -al, -able, -ic to the root of the nouns:

    Chemistry, technique, change, office, science, electron, physics, solve, compare, magnet, cylinder, experiment, desire

  1.  Form new words adding the prefix  ’’semi’’- and translate them:

    Sphere, tropical, final, cylindrical, automatic, diameter, tone, precious, circle, official

  1.  Translate the following word-combinations:

    Electric  circuits, a great variety of elements, semiconducting materials, to maintain a constant temperature, measuring techniques, emergency signals, a conveyer belt, to reproduce sound, to design electronic counters, to solve complicated engineering problems, to manufacture refrigerators, to generate electricity, the surrounding temperature changes

  1.  Translate the following international words:

    Temperature, mineral, conductor, thermal, progress, accumulate, technique, automation, radio, principle, refrigerator, energy, constant, metal, design, signal, cinematography

  1.  Find in the text:
  2.  synonyms to the following words –a great number, dielectric, to give an effect (impact), type, use, complex, to produce, able, to make, very good (perfect), permanent
  3.  antonyms to the following words –to reduce, gradually, to destroy, impossible, insulator, narrow, to reject
  4.  Make up word-combinations using the words “electric” and “semi-conductor” with the following nouns: circuit, current, power, device, detector, material, physics, electronics, technology, engineering, diode.
  5.  Translate the sentences paying attention to the meaning of the words in bold type:
  6.  Semiconductors are neither good conductors nor good insulators.
  7.  Energy can neither be created nor destroyed
  8.  Matter can neither appear nor disappear by itself.
  9.  The greatest part of matter on the Earth is either liquid or gas.
  10.  Some sixty or seventy years ago semiconductors didn’t exist either in electric industry or in radioengineering.
  11.  Silicon and germanium can be made either p-type or n-type semi-conductors.

  1.  Translate the sentences:

  1.  Після відкриття напівпровідників вчені намагалися знайти шляхи їх використання у різних галузях науки і техніки.
  2.  Крім застосування в техніці напівпровідники широко використовуються у повсякденному житті.
  3.  Провідність напівпровідникових матеріалів різко зростає з нагріванням.
  4.  Напівпровідникові фотоелементи спроможні трансформувати енергію сонця в електричний струм. Ми можемо використовувати їх для освітлення, розмістивши їх на даху будинка.

  1.  Translate the following attributive word-combinations:

semiconductor thermo-electric generator, current-carrying conductor, electrical engineering problem, emergency sygnal system, high-temperature range, cotton insulation layer, energy accumulation process, electronic counting machine.

  1.  Translate the following sentences and make up questions to them:

  1.  The first practical use of semiconductors was as crystal detectors in the earliest radio receivers.
  2.  At present semiconductors have found wide use in all kinds of complicated devices such as television and radio sets, refrigerators and many others.
  3.  Owing to semiconductors we are able to convert heat directly into electricity without boilers or other machines.
  4.  Thermocouples made of semiconductors and capable of producing both heat and cold.
  5.  A photo-cell is also a small electric station feeding on light.

TEXT 9 B.

Semiconductor Laser.

 Give a summary of the text.

Semiconductor quantum generators occupy a special place among the optical quantum generators. The size of a ruby crystal laser comes to tens of centimetres while a gas generator is about a metre long. A semiconductor laser is a few lengths of a millimetre long. Whereas the density of its radiation is hundreds of thousands of times as great as that of the best ruby lasers. For example, the device shown in Fig. 1 is 0.4 mm on each edge, with the junction lying in a horizontal plane through the centre.

All previous solid-state lasers needed energy supplied from external light sources, usually an intense burst of light from a flashtube. In the new gallium-arsenide injection lasers, pump energy is supplied directly by injecting electrons into the diode. Now modulation of the laser beam can be achieved by modulating the input current source. Semiconductor lasers operate under pulse and permanent regimes.

 Notes:

Burst –спалах 

Flashtube –спалахуюча лампа

By injecting –вводячи

Input –вхiд

Junction region

|not to scale|

Fig. 1.

TEXT 9 C

Semiconductors in modern technology.

Translate the text using a dictionary:

During the past several decades technology has posed problems that have required new methods and new materials for their solution. There have appeared heat-resisting alloys, superhard and light alloys, plastics, organic glass, sponge-glass and new building materials. The electric industry has added to its metals and insulators a group of semiconductors.

An investigation of the physical nature of semiconductors and a scientific explanation of semiconductivity have broadened the theory of semiconductors and have elucidated fresh facts that make possible the solution of many new technical problems.

The study of semiconducting materials which revealed their unique properties, such as dependence of conductivity on heat and light, opened up great possibilities for various uses of semiconductors.

There are altogether several hundred materials which have been studied and identified as semiconductors. Germanium and silicon seem to be the most useful semiconductor materials at present. They are widely used in modern electronic techniques, for example, in rectifiers, transistors, thermopiles, non-linear resistors and so on.

At present two semiconductors, germanium and silicon, are of special interest as they form the basis of the transistor –an electronic amplifier –in which the amplified current is emitted and transported within the semiconducting solid. As long as transistors are constructed of solid materials, their size can be made smaller as compared with tubes of corresponding electrical performance. They are more strong and reliable. The highest quality radio receivers and the most complex apparatus for signalization, automation and remote control become more and more tiny in size and cheaper thanks to the application of semiconductors.

The semiconductor devices are used in measuring technique, computers, radio and TV-sets for transmission of signals, for automation and remote control of a variety of processes, for switching on engines, for the production of sound, protection of high-voltage transmission lines, speeding up some chemical reactions, and so on. Semiconductors convert alternating current into direct current, amplify high-frequency oscillations and generate radiowaves, thereby replacing vacuum devices. They can convert heat energy into electric energy without machines, store light and release it on demand, etc.

Although this list could be continued, the number of applications named is sufficient to appreciate the importance and role of semiconductors in modern technology.

The introduction of semiconductors into industry began not long ago. Some fifty or sixty years ago semiconductors did not exist either in electric industry or in radio engineering. Now the semiconductor industry is developing very rapidly. Its very first steps showed that they may change our technological patterns entirely. Broad automation of all technical processes and their control from one centre will become a method easily attained in various industries. It will bring to a steep rise in labour productivity.

Semiconductors help to solve such fundamental problems as the direct conversion of thermal energy and the solar energy into electric power, and also electric energy into mechanical energy, and vice versa, without any complex mechanism with moving parts. Semiconductor couples convert heat directly into electricity just as a generator does it. A new industry –helioengineering –has emerged. Solar batteries are successfully operating on sputniks and spaceships.

This special place occupied by semiconductors in modern physics and engineering and potential possibilities of application are due to the peculiarities of their properties which are not found in other materials. When considering the future development of semiconductor technology, we must keep in mind that it is one of the youngest branches of science and technology – of the same age as nuclear physics.


 

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