English_2 / юниты / 20 Unit 17

5

Unit 17

Grammar: Verbals

TEXT 17 A

AN EFFICIENCY OF NEARLY 100 PER CENT

Perhaps the most interesting thing about semiconductor lasers is that they can transform electrical energy directly into light wave energy. They do this with an efficiency approaching one hundred per cent as compared with a maximum of about one per cent of other lasers.

Semiconductor lasers are sure to open up great prospects for solving various scientific and technical problems. Calculations and experiments show that already super-hard substances (diamonds, rubies and so on) and hard alloys can be worked profitably by ruby lasers, for example. The development of powerful-efficient semiconductor lasers is certain to considerably raise the power efficiency of a number of technological processes.

The high frequency radiation of optical generators makes it possible to transmit an enormous flow of information. This is of great significance for the advancement of communication techniques. The small dimensions of the semiconductor laser make it especially suitable for use in super-speed computers.

Ruby crystals about ten centimetres long can intensify light ten times. The same results can be obtained from semiconductor crystals only a few microns long. Thus it is possible to develop quantum light intensifiers with maximum sensitivity.

Theoretical calculations have shown that devices similar to semiconductor lasers can also transform the energy of light radio waves into electrical energy with an efficiency of close to 100 per cent. This means that electric power may be transmitted over considerable distances with negligible losses without the use of transmission lines.

The high efficiency of semiconductor lasers opens up possibilities of developing extremely economical sources of light. Luminescent lamps were instrumental in increasing the efficiency of light sources from two to ten per cent. Semiconductor lasers will increase this efficiency several times over. In addition, semiconductor devices will greatly increase the efficiency of luminescent crystal lasers. Semiconductor lasers are sure to have a great future.

The diversity of available lasers is now determined by the fact that all possible states of matter are used as their active media – gases, liquids, solids ad plasma. The use of each new form of matter as an active medium is associated with definite stage in the development of quantum electronics. The research for various active media may be regarded as the method of quantum electronics at an early stage of its development. Over the past decades high-power lasers have found a place in manufacturing processes: welding, heat–treating of parts to improve their surface, properties, cutting, drilling of small holes and in electronic devices and medical instruments. In all these operations laser systems have made productive lines more efficient and have reduced costs.

Answer the questions:

1. What is the most interesting thing about semiconductor lasers?

2. What prospects do semiconductor lasers open up?

3. What are the advantages of the semiconductor laser?

4. What results can be obtained from the semiconductor crystal in the field of intensifying light?

5. What have theoretical calculations shown?

6. By what fact is the diversity of available lasers determined?

7. In what operations have laser system made productive lines more efficient?

Exercises

I Translate the following words paying attention to the suffixes:

useful-useless powerful-powerless

fruitful-fruitless lawful-lawless

careful-careless

doubtful-doubtless

II Translate these words paying attention to negative prefixes:

Uneconomic, unimportant, unknown, unlimited, unofficial, unequal, unexpected, disappear, disarm, improbable, irresponsible, incapable, unlock, unload, unpack.

III Give verbs of the same root and translate them:

Collision, explosion, generator, sensitive, transform, electrical, efficiency, intensify, profitably, directly, scientific, technological, communication.

VI Form words after the models and translate them:

1. V + ment: to move- movement

2. V + ion(tion, ation): to collect- collection

2. to agree, to develop, to govern, to improve, to pay, to settle, to advance;

2. to combine, to connect, to introduce, to produce, to restrict, to transmit, to include, to transport, to communicate, to calculate, to inform, to limit.

V Form words with opposite meaning by adding the prefixes -un, -dis, - im, -ir, -in:

Comfortable, equal, limited, approve, appear, connect, probable, possible, mobile, ability, capable, complete, direct, experienced, responsible, regular, reliable.

VI Translate the following words and state their parts of speech:

Reasonable, achievement, employer, important, unimportant, resistance, resistant, darkness, weakness, departure, pressure, changeable, comparable, dangerous, restrictive, helpless, accessible, incorrect, unnatural.

VII Form adjectives adding the suffixes:

-able, -al, -ant, -ful, -ish, -(ive), -less, -ous, -y.

electric, power, consider, technology, suit, economic, compare, change, profit.

VIII Form nouns adding the suffixes: -er(or), -ance(ence), -ion(tion), -ment, -ness to the following verbs:

Calculate, communicate, transmit, develop, connect, improve, advance, generate, produce, restrict.

IX Form adverbs adding the suffix -ly to the following adjectives:

Extreme, direct, wide, economical, certain, considerable, efficient, great, successful.

X Translate the following sentences, paying attention to the underlined word combinations:

1. The electron has an electron charge as great as that of a proton. 2. The sun is much nearer to the Earth than other stars. 3. The moon is much smaller than the Earth. 4. The weight of a proton or a neutron is about two thousand times that of an electron. 5. Ruby crystals about ten centimetres long can intensify light ten times. 6. Semiconductor crystals a few microns long can also intensify light ten times. 7. The size of a gas generator is about 1 metre long. 8. A semiconductor laser is a few lengths of a millimetre long. 9. The new radio set is half the size of the old one. 10. The most modern instrument is half the weight of the outdated one. 11. The density of a semiconductor laser radiation is hundreds of times as great as that of the best ruby lasers. 12. The weight of this heavenly body is half as much as that of another meteor. 13. Carbon fibre, a mixture of carbon and plastics, is twice as strong and twice as light as steel.

XI Choose the right variant and read it aloud:

a) Quantum electronics is used for generating radio waves;

amplifying radio waves;

attenuating radio waves;

b) Quantum amplifiers are used for increasing the sensitivity of radio

receivers;

decreasing the sensitivity of radio

receivers;

reducing the sensitivity of radio

receivers

c) In order to reduce the it is necessary to keep down the radio receiver’s

noise due to heating temperature;

to keep up the radio receiver’s

temperature

XII Arrange the following words in pairs of synonyms and translate them:

for example surprising a

enable v production n

manufacture n size n

operate v work v

apply v near to

close to for instance

change v vary v

dimension n make possible

enormous a great

major a accuracy n

precision n main a

amazing a employ v

XIII Arrange the following words in pairs of antonyms and translate them:

major a heat v

rapidly adv failure n

cool v more a

less a (the) best

inaccurate a

(the) worst a

success n external a

conventional a minor a

accurate a unusual a

internal a slowly adv

increase v reduce v

efficient a inefficient a

XIV Make up sentences using the following pattern and translate them:

Pattern:

Luminescent lamps were instru- increasing the efficiency of light sources

mental in from 2 to 10 per cent.

Semiconductor lasers are instrumental increasing the efficiency of light sources

in several times over.

Semiconductor devices increasing the efficiency of luminescent

crystal lasers.

solving various scientific and technical

problems.

transforming electrical energy into light

wave energy.

Controlling the generator’s oscillations.

XV Translate into English:

1. Ми знаємо, що світлові та радіо хвилі є електромагнітними коливаннями.

2. Відомо, що в звичайних умовах всі тіла поглинають або радіо, або світлові хвилі.

3. Лазерний промінь не створюється ні ниткою розжарювання(filament), ні електричною дугою.

4. Кажуть, що промінь створюється у рубіновому крісталі.

5. Повідомляють, що промінь лазера в тисячу мільйонів разів яскравіше, ніж сонячне світло.

6. Вважають, що роботи по створенню першого оптичного генератора на півпроводниковому кристалі арсенuдa галію завершились наприкінці 1962 року.

XVI a) Make up questions to the following answers:

1Yes, plasma is the fourth state of matter. 2. It abounds in the universe. 3. Plasma is increasingly entering the service of man. 4. Engineers have used plasma for doing construction work. 5. They made a plasma knife. 6. The plasma knife does the job of a cutter. 7. Yes, the plasma knife is used where conventional welding apparatus cannot operate. 8. Yes, the plasma knife also has a direct current transformer. 9. No, the plasma does not differ in appearance from any conventional welding apparatus. 10. Yes, with the help of a d.c. transformer the gas mixture is ionized and forms plasma.

c)Speak about the practical application of plasma.

XVII Translate the following international words:

maximum, minimum, micron, accelerator, meteorology, navigation, characteristic, concentration, argument, robot, physical processes.

TEXT 17 B

LASER TECHNOLOGY

Translate the text using a dictionary:

This century may well become the century of lasers. This miracle-making beam is the symbol of the 20^th century technology. There is no doubt that the use of lasers will be very widespread in the nearest future. Quite possibly, it will be as widely used as electronic devices are today. What is laser? It is a device for making and concentrating light waves into a very intense beam. The letters LASER stand for Light Amplification by Stimulated Emission of Radiation. The light made by a laser is much more intense than ordinary light. With ordinary light all the light waves are of different lengths. With lasers all the light waves are of the same length, and this increases the intensity.

The laws of quantum mechanics govern the functioning of lasers. The laser is a device in which energy (thermal, chemical or electric) is transformed into electromagnetic radiation energy, a laser beam with maximally low entropy.

The quality of laser energy is determined by the possibility of its high concentration both in space and in time. The laser beam is first compressed in time, i. e. transformed into a short pulse. Then it may be compressed in space focusing it in a fine point with a diameter of the order of a light wave length, thus obtaining energy density which, to date, evens that of a nuclear explosion. Laser energy can also be concentrated within a very narrow spectrum interval. This makes the laser a very fine instrument.

The world’s first ruby laser had a dark-red beam. Other lasers were then produced, whose beam oscillated in crystals of a different composition, in semiconductors, gases, and liquids. And the beams were blue, green or invisible-infrared. What they have in common is that the beam is always space-bound and carries a highly pointed and powerful flux of energy.

Laser energy may be transformed practically without loss into many familiar forms of energy.

As each of new kinds of energy was mastered, mankind gained new possibilities for its development. But discovery of the laser signifies something greater than simply mastering a new kind of energy. Wide laser application in production signifies a revolution in the implements of labour - the most flexible and mobile element of the productive forces.

TEXT 17 C

LASER IN THE CLOTHES-MAKING INDUSTRY

Give a summary of the text

Clothes-making factories have the following procedure for mass sewing of clothes. Thick stacks of cloth are put on a large layout table, and then each stack is cut out with knives which look like jig-saws to fit a pattern. This leads to a considerable waste of cloth. In the process of bringing parts of clothes to fitness rather wide strips of material are thrown out as refuse.

Now a practically waste-free technology seems to have been found for this operation. An installation for laser layout of cloth designed at a Special Design and Development Bureau of the Clothes Manufacturing Industry has been built by the Shipyard in St. Petersburg.

In keeping with a set programme, a laser beam burns through a thick stack of cloth without shifting the layers (as it happens in cutting with a knife) and it does not require making allowances “just in case”.