CABLES. COAXIAL AND POLYTHENE CABLES
It is a well-known fact that the basic technological element in communication is a transmission line and its main part is a cable.
The construction of a cable is comparatively simple. Mainly it consists of insulated conductors that form a metallic circuit. The conducting wires are made of metals. The space between central conducting wire and a concentric cylindrical conductor is filled with some dielectic material. It may be air, polythene, bakelite or some other.
The outer conductor of a cable is normally connected to Earth. In this construction high-frequency currents travel only on the surface of the conductor, since the solid inner part of it causes resistance to the flow of current. And resistance causes a drag eliminated by the coaxial construction of the cable. And that is the main advantage of a coaxial construction. But it also has disadvantages, and one of them is its comparatively high cost. The dimensions must be very accurate for the range of the frequencies to be carried. This property of coaxial cable makes its construction rather costly.
Nowadays a great number of coaxial cables of various length and different constructions are being produced and laid all over the world.
The main function of a coaxial cable is to transmit power from one element of a system to another with minimum energy loss. It may be, for example, used in the aerial of a radio system. From the aerial, as we know, energy is transmitted into, or received from, space, or the atmosphere.
The properties of cables are being constantly improved. One of the popular ways of improving their properties is the use of polythene as an insulating material.
Polythene is thermoplastic insulating material mostly used in cases where a chemically-resistant plastic material is needed.
Polythene cables belong to the type of cables widely used in transmitting electrical energy from area to area, since polythene is the popular and highly useful insulating material of today.
Polythene cables are known to have a number of advantages: they may be used for both a conductor insulation and a sheath, which makes them one of the most usable substance in industry. There exist two main types of polythene cables: the one having polythene insulation for the conductors, and the other having paper insulation. To these belong lead-sheathed paper-core cables. The number of pairs in different cables is also different. Of them the cables including 100 pairs and more have natural polythene sheaths.
Unlike lead-covered cables, polythene ones can be laid directly in the ground without ducts since they are corrosion-proof, while lead-sheathed cables are usually laid in asbestos-cement ducts since they can be easily corroded. Another advantage of polythene cables is that they can be used in much longer length than lead-covered ones.
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bakelite - название синтетической смолы
drag – торможение, сопротивление
dimension – размеры, величина
eliminate - устранять
corrode – ржаветь, разъедать
core – сердечник, комплект жил кабеля
duct – канал, труба
lead - свинец
sheath – оболочка, обшивка
ground – земля, заземление
GRAMMAR EXERCISES
I. Translate the following sentences, pay attention to the Objective Infinitive construction (Complex Object).
1. The engineers consider the cyclotron to be the simplest and oldest type of accelerator. 2. We believe electrons in a synchrotron to travel on a circular orbit inside a narrow vacuum vessel. 3. The designers may expect the electrons to be injected into the vessel from a smaller linear accelerator. 4. They supposed the greater part of energy to be used for supplying plants in that region. 5. We saw thedimension of the body change under different temperature conditions. 6.Any student must know a voltmeter to be used for mea potential difference between any two points in a circuit. 7. Engineers think these cables to disturb the reception. 8. We thought superconductive materials to be produced in Kiev. 9. The designers assume the system operation to be improved as a result of some of its parts.
II. While translating indicate those sentences in which Complex Object is used.
1 .This is quite the wrong view to take. 2. Assume the base of the column to be furnished with angles on the flanges. 3. Rollers not only cause a reaction to act at right angles to the supporting surface but also serve the purpose of allowing structures to expand and contract with changes in temperature. 4. Outside and in, the modern store must offer an invitation to the passerby to enter and to spend.
III. Translate the following sentences and define the functions of "to have, to be".
1. The form of energy most required by us is technical energy. 2. There are four factors to consider in the design of this reflector. 3. This gigantic plan is to be completed in the short period of five years. 4. The open end of the tube is connected to the apparatus the pressure within which is to be measured. 5. An electromagnet or temporal magnet is one in which the magnetic field is produced by an electric current.
IV. Point out which of the sentences "to have, to be" are used as Modal Verbs. Translate the sentences.
1. Draglines are operated where excavation has to be carried out at some distance from the machine. 2. Many basic principles are still to be established. 3. The time is nearing when international agreements will be drafted to govern the design and operation of nuclear vessels. 4. If practical answers are to be found and the factor of safety is to be put on a firm calculable basis a large number of complicated problems will have to be solved. 5. Care should be used to obtain amount of light in buildings in which men are to work. 6. The drawings show how the materials are to be incorporated into the structure; the specifications state the quality and the methods, which are to be employed.
LEXICAL EXERCISES
V. Translate the following stable expressions into Russian.
| And there we go ... | The idea of it... |
| The case stands ... | More to the point... |
| By all means ... | None any too ... |
| Can I help you ... | This is it... |
| Certain as the rising sun ... |
VI. Translate the following sentences, pay attention to the words in bold type.
1. The use of light metals in industry will amountto a higher and higher per cent. 2. There is a great amountof titanium in the Urals. 3. A square thing does not fit into a roundhole. 4. The Earth roundonce in one day and one night. 5. There is a bus stop round the corner. 6. In order to come to the station you must roundthe corner. 7. The Earth makes its yearly roundin 365 or 366 days.
VII. Translate the following sentences, pay attention to the words in bold type.
1. Television is an important meansof communication. 2. This fact meansthat the number of radio stations in our country will increase. 3. All technical meanswill be perfect in future. 4. A number of modem houseswill be constructed in this region. 5. The instrument cabin of a spaceship housesvarious transmitters, power sources and other equipment. 6. This system housesall technological and auxiliary services. 7. The obtained resultis of great practical importance for the development of these systems. 8. The application of powerful outer space relays resultin better communication. 9. Engineers achieved great resultsin constructing semiconductor devices. 10. The application of semiconductor devices results in better operation of this equipment. 11. The totalnumber of power stations in the world is growing constantly. 12. All the devices of this laboratory totalabout two hundred.
VIII. Translate the following word combinations into Russian
1. space communication; 2. space communication system; 3. long-range space communication system; 4 the production growth; 5. communication channels; 6. long-range communication channels. 7. long-range communication channels improvement; 8. the radio station network; 9. outer-space relays; 10. the outer-space relays application; 11. the outer-space relays improvement; 12. radio engineering purposes; 13. high voltage transmission lines.
IX. Arrange the following words to the similar meanings
to grow, to house, powerful, total, to contain
a mean, artificial, a way, to use, great, to increase, amount, to apply, man-made
X. Translate the following words with the prefix re- and make up the sentences with them.
re-form v, renew v, re-radiate v, readjust v, reuse v, re-entry n
XI. Translate the following text.
Cable laying
The process of laying cables is known as “long-length cabling”. Cables may be laid directly in the ground or put into ducts already laid. Cables laid directly in the ground must always have some protection against corrosion. Faulty cable must be taken out and inspected.
The cost of direct laying is rather low but laying of this kind has a disadvantage: directly laid cables cannot be taken out. In cities it is not possible to use direct laying and cables must be put in ducts. In tunnels and subways cables are usually put on walls. In cold weather cables must be kept warm or warmed before laying. No cable should be laid when the temperature is low because of the possible damage to the paper core. If a cable is faulty or if it is corroded, it stops operating or operates badly.
Most common faults in cables are a break, a short, and a contact between conductors in a multi-wire system. Naturally, different combinations of these faults are also possible. Faulty cables are taken out and replaced by new ones.
GRAMMAR REFERENCES
Употребление оборота Complex Object
В английском языке оборот Complex Object употребляется для упрощения сложноподчиненных предложений с дополнительным придаточным предложением.
Упрощение происходит следующим образом: подлежащее и сказуемое главного предложения сохраняются, союз that опускается, придаточное дополнительное предложение становиться сложным дополнением.
Оборот Complex Object состоит из двух частей. Первая часть — существительное в «общем» падеже или местоимение в «объектном» падеже; вторая часть — инфинитив, который выражает действие, выполняемое лицом или предметом (cyществительным или местоимением).
Модель: S + Р + Noun/Pronoun + Infinitive
Глаголы, после которых употребляется Complex Object, делятся на пять групп.
1. Глаголы, выражающие суждение, предположение, мнение: to consider, to believe, to think, to suppose, to expect и др. После глаголов этой группы (кроме to expect) чаще всего употребляется инфинитив глагола to be.
We believe that these experiments are very important. =We believe these experiments to bevery important. Мы полагаем, что эти экспериментыочень важные.
2. Глаголы, выражающие требование, просьбу: to реrmit, to request, to demand, to command и др.После глаголов этой группы употребляется Complex Object в страдательном залоге. После глагола to ask всегда стоит предлог for.
Не asked for the letter to be sent offat once.
Он попросил, чтобы письмо отправилисразу.
3. Глаголы, выражающие восприятие посредством органов чувств: to see, to hear, to feel, to notice, to observe, to watch, инфинитив при этом употребляется без частицы to. После глаголов этой группы оборот переводится на русский язык придаточным предложением, начинающимся с союза «как», а иногда союза «что»:
We see the water boilin the boiler.
Мы видим, что вода кипитв котле.
4. Глаголы, выражающие желание, ненависть, любовь:
to want, to desire, should (would) like, to like, to hate, to intend и др.
После глаголов этой группы оборот Complex Object переводится на русский язык придаточным предложением, начинающимся с союза «чтобы», «когда».
1wanted him to be invitedhere.
Я хотел, чтобы его пригласилисюда.
We hate you to say such things.
Мы ненавидим, когда вы говоритетакие вещи.
5. Оборот Complex Object употребляется после ряда глаголов, которые требуют дополнения с предлогом: to wait for, to rely on, to count on (upon) и др. В этих случаях перед оборотом Complex Object стоит предлог.
We waited for them to beginthe conversation.
Мы ждали, чтобы они началиразговор.
/ count upon him to helpme.
Я рассчитываю, что он поможетмне.
Глаголы, после которых употребляется оборот Complex Object, должны быть в действительном залоге.
Глаголы, после которых чаще всего употребляется оборот Complex Object:
to assume — предполагать, допускать
to believe — полагать, верить
to consider — рассматривать, учитывать
to desire — желать, просить
to expect — ожидать, предполагать
to feel— чувствовать, ощущать
to hear — слышать
to know — знать
to prove — подтвердить, испытывать
to require — требовать
to suppose — допускать, предвидеть
to see — видеть
to show — показывать
to think — думать, рассчитывать
to wish — желать, хотеть
to want — хотеть, требовать
to watch — наблюдать, следить
Перевод оборота Complex Object на русский язык
Этот оборот переводится на русский язык придаточным дополнительным предложением с союзами «что», «чтобы», «как».
The Indefinite Infinitive в действительном и страдательном залогах выражает действие, одновременное с действием глагола-сказуемого, и переводится на русский язык тем же временем, что и сказуемое основного глагола.
The experiment showed them to obtaingood results.
Эксперимент показал, что они получилихорошие результаты.
The Perfect Infinitive в действительном истрадательном залоге выражает действие, предшествующее действию глагола-сказуемого, и переводится прошедшим временем.
Не proved the reaction to have runin the cold.
Он подтвердил, что реакция произошла на холоде.
После глагола to expect инфинитив переводится будущим временем.
We expect(ed) the reaction to be overin two hours.
Мы полагаем (полагали), что реакция закончитсячерез два часа.
Инфинитив сложного дополнения в страдательном залоге после глаголов allow, permit (разрешать), enable (давать возможность) переводится инфинитивом действительного залога, асуществительное или местоимение, стоящее перед инфинитивом, становится дополнением.
A whole series of experiments enable the problem to be solved.
Целый ряд экспериментов дал возможность решить проблему.
LEXICAL REFERENCES