. compresio . . , , , . . , .
.
, . .
Burning or combustion is the process of uniting of fuel or combustible with oxygen in the air.
, .
burning fuel combustion combustible , .
, , . - .
, . , . , . : ; .
.
, .
Unit 7
RADIO COMMUNICATION
Radio communication is the transfer of high-frequency energy from the transmitter to the receiver. Accordingly, the main components of radio communication of any kind are a transmitter and a receiver.
The function of a transmitter is to generate electrical oscillations at radio frequency which is called the carrier frequency. The main components of a transmitter are an oscillator, amplifiers, and a transducer. The oscillator of a transmitter converts electric power into oscillations of definite radio frequency. As for amplifiers, they increase the intensity of oscillations produced by the oscillator and retain the definite frequency. The transducer converts the information to be transmitted into a varying electrical voltage. In case of sound transmission a microphone serves as a transducer.
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Other important components of radio transmitters are the modulator and the aerial. As for the modulators, they use proportional voltages for controlling the variations of oscillation intensity. And the aerial is that part of a radio system from which energy is transmitted into or received from the space (or the atmosphere). The aerial must be insulated from the ground and may occupy vertical or horizontal position. In case the transmitter aerial occupies vertical position, the receiver aerial must be also vertical and vice versa. It applies to all radio frequencies except short waves. In usual amplitude-modulated broadcasting the receiver aerial may consist of a wire wound on a core.
Most modern radio receivers are of super heterodyne type. In them an oscillator generates a radio-frequency wave that is mixed with the incoming signal. As a result, a radio-frequency wave of lower frequency (called intermediate frequency) is being produced. In order to tune the receiver to different frequencies, the frequency of oscillations changes but the intermediate frequency always remains the same.
The oscillator is tuned by changing the capacity of the capacitor in its tuned circuit. The aerial circuit is also tuned by a capacitor in its tuned circuit.
What are the characteristics of a good radio receiver? It should have high selectivity and fidelity and low noise. Selectivity is achieved by a receiver receiving signals from one station and rejecting them from another station operating on a nearby frequency. A high fidelity receiver contains both the tuner and amplifier circuits of a radio. And the high fidelity radio may consist of a separate audio-amplifier and a separate radio tuner. High sensitivity is achieved by having numerous stages of amplification. But it should be noted that high amplification is used only if high fidelity of the system is achieved. It is also important to achieve as low noise as possible.
_____________________
Retain ,
Wire winding
Core .
Heterodyne
Reject ,
Fidelity
GRAMMAR EXERCISES
I. Translate the following sentences, pay attention to the Subjective Infinitive construction (Complex Subject).
A. 1. Electronics is thought to be a young science. 2. The electric generator is known to be a machine that converts mechanical energy into electrical energy. 3. Alpha rays are considered to be positively charged helium atom. 4. An electric cell is believed to consist of an electrolyte and two electrodes. 5. This voltage source was supposed to supply current for this circuit. 6. The value of the output voltage of the cell was found to depend only on the material used. 7. Due to these experiments this substance was shown to be a good conductor. 8. The secondary coil of the transformer is assumed to have more turns than the primary one. 9. Cadmium was reported to be useful for application in transistor. 10. This scientist is expected to make a report on the fundamentals of radio engineering. 11. The designer is said to construct a new device by using semiconductors. 12. The antenna was found to receive only a small part of energy radiated by the transmitter. 13. Atomic nuclei are believed to be composed of protons and neutrons.
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B. 1. Yablochkov is known to be the inventor of the electric candle. 2. All the members of the committee are reported to have been enthusiastic about the plan. 3. "Hamlet" is considered to be the summit of Shakespeare's art. 4. Substances are known to burn when they unite with the oxygen of the air. 5. The years that he had spent abroad seemed to have taught him much. 6. He is supposed to be one of the greatest writers of our time. 7. It appeared to be quite another man. 8. Shakespeare is known to have been an actor and playwright in one of the leading companies of players at the end of 1580.
II. While translating the following sentences point out the Complex Object and the Complex Subject constructions.
1. For the pressure to be reduced to safe limits the foundations may be widened. 2. Such method of making drawings requires every size of the object to be divided by the proportion of the scale. 3. It is usually not required that a first year student should ink and colour his drawings when they are done to this scale. 4. If it is assumed to be tension and proves to be compression, this will be indicated by a negative value in the result. 5. We assume these charts to give accurate results for such sections, which are reinforced in tension or compression. 6. The point at which a body ceases to be elastic is termed the yield point, the body is then said to have undergone plastic deformation or flow. 7. Concrete piles are less likely to be injured in driving than wooden piles. 8. Tapered piles appear to have a bearing capacity in soft material considerably greater than a straight pile.
III. Point out the construction "for+infinitive". Translate the following sentences.
1. On completion of a contract of long duration it is a sound policy for the plant to be sent to the repair deport for thorough examination. 2. Architecture is a difficult art, for it requires a special type of imagination and takes long years of training and experience to produce a capable architect. 3. In pushing over or falling trees, which are too large for the tractor to move by blade, the roots of the trees should be exposed and cut through. 4. In its way the camera can be even more deceptive than a drawing for the good architectural photographer can make beautiful photographs of the ugliest structures. 5. The six rivets necessary for the web connection to be able to take up the design shear are arranged as shown.
IV. Translate the following sentences into Russian, pay attention to the Infinitive.
1. Real water vapour and steam are known to be completely invisible. 2. A rod of ebonite, which has been rubbed with the wool flanell, is found to have the property of attracting light objects such as small pieces of paper, cork, etc. 3. When heat is transferred from one part of the body to another without any progressive motion of the parts of the substance, the heat is said to the transferred by conduction. 4. A book lying on a table is expected to keep its position without any difficulty, as one knows it to be in a state of equilibrium. 5. Heat is said to reach the cooler end of the rod by conduction along or through the material of the rod. 6. All metals are known to consist of minute particles called molecules.
V. Translate the following sentences pay attention to the construction "for+ noun+ infinitive".
1. 8 minutes are required for light to travel from the Sun to the earth. 2. Nearly a month is required for the moon to circle the Earth. 3. The satellite of Neptune is too far away for its size to be known with any accuracy. 4. For combustion to be rapid, the fuel and oxidant must be quickly mixed. 5. For ions to be formed, a considerable amount of energy must be given to the parent atoms. 6. In order for the airplane to climb, thrust must exceed drag.
VI. Change the following sentences according to the model.
Pattern: Modern systems are known to be complex and varied.
It is known that modern systems are complex and varied.
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1. Physical, economic, and business system are known to have technical and human aspects. 2. Industrial engineering accomplishments are known to have reduced labour costs. 3. The term "industrial engineering" is known to be contemporary with the beginning of industrial revolution. 4. The first point of impact of the industrial revolution is known to have been the British cotton-textile industry.
VII. Translate the following text in written form.
CONDUCTORS
Conductors are materials having a low resistance, so that current easily passes through them. The lower the resistance of the material, the more current can pass through it. The most common conductors are metals, and silver and copper are the best of them. The advantage of copper is that it is much cheaper than silver. Thus, copper is widely used to produce conductors. One of the common functions of wire conductors is connecting voltage source to a load resistance. Since copper wire conductors have a very low resistance a minimum voltage drop is produced in them. Thus, all of the applied voltage can produce current in the load resistance. Most materials change the value of resistance when their temperature changes.
LEXICAL EXERCISES
VIII. Give Russian equivalents of the following word combinations (terms).
1. artificial horizon 7. original equation
2. remote control 8. straight angle
3. direct current 9. low-flying
4. acrobatic maneuvers 10. short-circuit
5. parasitic antenna 11. rapid change
6. aerodynamic missile 12. low water
IX. Translate the following sentences into Russian, pay attention to words in bold type.
1. During eighteenth and nineteenth centuries chemists slowly had been accumulating evidence that all matters were composed of atoms. 2. The photographic evidence clearly indicates that approximately 90 per cent of all visually observable meteors are of cometary origin. 3. The close approach of Mars brought very little new evidence concerning the origin of geometrical patterns on its surface.
X. Translate the following words with prefixes dis-, in-, im-, il-; un-.
continuous a - discontinuous correct adj - incorrect
charge v - discharge divisible adj - invisible
close v - disclose accurate adj - inaccurate
connect v - disconnect movable adj - immovable
advantage n - disadvantage logical adj - illogical
regular adj - irregular important adj - unimportant
complete adj - incomplete
XI. Form words with the opposite meaning using prefixes and translate them.
un-: desirable, wanted, solved, natural, limited, able
non-: metallic, magnetic, ferrous, productive, breakable
in-: complete, dependent, ability, expensive, effective,
im-: pure, possible, perfection, patient, permanent,
ir-: regular, responsible, respective, relative
il-: logical, legal
dis-: order, advantage, to continue, to connect, to like
mis-: use, information, understanding, to understand
XII. Translate the terms which are composed of noun+participle I (gerund) + noun.
Pattern: pulse forming coil
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↓
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↓
: .
error indicating circuit plutonium- producing reactor
direction-finding receiver isotope-handling equipment
data-translating system spectrum-measuring detector
error-measuring system information destroying process
beam-forming cathode information-carrying capacity
electron-emitting source frequency-dividing circuit
receiver feeding battery voltage regulating system
XIII. Arrange the following words in pairs according to opposite meaning.
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1) huge a) tremendous
2) probable b) improbable
3) to propel c) to radiate
4) sufficient d) small
5) to pick up e) fast
6) tiny f) insufficient
7) exact g) inaccurate
8) slow h) output
9) input i) to stop
GRAMMAR REFERENCES
Complex Subject
Complex Subject . ; , , ( ).
, , to seem, to appear .
: Noun/Pronoun + P + Infinitive
Complex Subject . : , , , . to .
It is known that sunlight activated various chemical reactions.
Sunlight is known to activate various chemical reactions.
, .
is known . it that .
Subject :
1. , : to think, to consider, to believe, to suppose, to expect, to say, to report .
These fruit is known to be grown in the North.
, .
2. , : to order, to ask, to allow, to permit, to make, to cause .
All books were ordered to be returned within five days.
, .
3. , : to see, to hear, to feel, to notice, to observe, to watch .
They were seen to go home together.
, .
4. , : to appear, to happen, to chance, to turn out, to prove .
The doctor happened to be at home.
, .
- to appear -.
5. be + likely, sure, liable, unlike, certain. Indefinite Infinitive .
The goods are unlikely to be unloaded today.
,
Complex Subject there.
There appears to be possibility of conducting the experiment.
, .
Complex Subject :
1) :
to say (is, are said) ()
to see (is, are seen) ()
to hear (is, are heard) ()
to state (is, are stated) - ,
to find (is, are found) ,
to claim (is, are claimed) - ()
to think (is, are thought) , ()
to know (is, are known) ()
to report (is, are reported) ()
to suppose (is, are supposed) - ()
to expect (is, are expected} ()
to consider (is, are considered) ()
to believe (is, are believed) ()
to hold (is, are held) ()
to take (is, are taken) ()
to assume (is, are assumed) ()
2)
to seem
to prove
to appear
to happen ,
3) , - to be ( ):
to be likely
to be certain
to be unlikely
to besure ,
Complex Subject
Complex Subject :
) .
(is said, is known, is believed .), 3- (, , .). , , .
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Billions of stars are assumed to exist in the universe.
2 1 3 4
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) ( , , ), , .
The results are known to have been used in this experiment
, , .
, Complex Subject . , .
These forms of radiant energy have been found to travel through space with a big speed.
, , .
. to be .
Atoms were assumed to be indivisible particles of the elementary substance.
, () .
- to be + likely to be + unlikely. Indefinite Infinitive .
Under these conditions the output is likely to increase.
.
(to have been) .
This scientist is supposed to have developed a new method.
, .
, .
This method does not seem to offer any advantage.
, .
, .
Such reaction was not observed to happen.
He , .
