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LESSON TWO




Читайте также:
  1. A LESSON LEARNED
  2. LESSON FOUR
  3. LESSON FOUR
  4. LESSON FOUR
  5. LESSON FOUR
  6. LESSON ONE
  7. LESSON THREE
  8. LESSON THREE
  9. LESSON THREE
  10. LESSON THREE

I. Try to understand what text A is about by its title:

 

Text A

Communicating Through the Earth

1. How do we communicate with people beyond the horizon? What can be made to follow the curve of earth's surface?

2. Of course, we can send electrical signals through wires around any curves. In the Nineteenth Century, copper wires were strung across the continents1 and ocean floors and the world was united through telegraphy2. That takes a lot of copper, though, and a lot of maintenance.

3. We could send light-wave signals and do away with wires, but light waves move in a straight line and won't curve around the earth's bulge. We would have to set up relay stations or place mirrors in orbit to make that work.

4. Radio waves, like light waves but a million times longer, do better. They travel in straight lines, too, but the upper atmosphere contains regions rich in charged particles (the ionosphere) that tend to reflect3 the radio waves. It is as though there were natural mirrors in the sky. That makes it possible to send radio signals long distances, and in the Twentieth Century the world was united without wires.

5. However, the ionosphere is affected by the solar wind. When the sun produces flares, an electrical storm can take place that will disrupt radio communications.

6. But short radio waves (microwaves) can go right through the ionosphere4 and be amplified and sent on by communications satellites. As communications satellites improve, signals will be sent from place to place on earth with so little trouble that it would seem unreasonable to ask for anything better.

7. What can go through the earth itself? Light certainly can't. Radio waves can't. We can't even string wires through the earth to carry electrical signals.

8. One thing that does travel through the body of the earth is an earthquake wave, but it takes a very hard blow to set the earth to vibrating perceptibly5.

9. On the other hand6, certain massless subatomic particles called neutrinos travel at the speed of light and go through matter as though it weren't there. A beam of neutrinos7 could travel through trillions of miles of solid lead and come out the other end just about unaffected. Neutrinos reach us from every direction and almost every neutrino that does so passes right through the earth in less than a 20th of a second (and through us if we are in their paths).



10. This doesn't mean that neutrinos can't be detected. Out of many trillions, one neutrino may occasionally combine with an atomic nucleus and induce a detectable change.

11. Thus, huge vats of cleaning fluid made up of molecules that include chlorine atoms can serve as a "neutrino telescope". Such neutrino telescopes can be placed in mines, a couple of miles under the earth's crust. In that case, nothing can reach them but neutrinos, and, in this way, neutrino-producing reactions deep in the sun's core can be studied.

12. Scientists can produce neutrino beams without much trouble. Some day it might be possible to send them out in Morse code or in more complicated modulation. The day may come when improved neutrino telescopes, using water rather than cleaning fluid, will be placed all over the earth. Eventually television sets might be built that would incorporate the equivalent of neutrino telescopes and convert the signals directly into sight and sound.



13. If this could be done, communications satellites would be unnecessary and so would relay stations of any sort. Any two points on earth's surface (or in mines, or under the sea) would be connected by a mathematically straight line along which neutrinos would move at the speed of light. There is no way of communicating more quickly.

14. For that matter8, neutrinos move in a straight line throughout the universe. They are unaffected by the electromagnetic fields and dust clouds that can disrupt or block microwaves and light.

15. In the end9, then, it may be that communications among worlds would be carried out through neutrino beams.

16. Perhaps that is why we aren't detecting signals from other intelligent civilizations out there. We're looking for beams of microwaves, but perhaps we should be looking for beams of neutrinos.

 

Notes

1. copper wires were strung across the continents – медные провода опоясывали континенты

2. the world was united through telegraphy – связь в мире осуществлялась по телеграфу

3. tend to reflect – имеют тенденцию (обыкновение) отражать

4. can go right through the ionosphere – могут проходить непосредственно через ионосферу

5. but it takes a very hard blow to set the earth to vibrating perceptibly – но для того, чтобы привести землю в состояние сильной вибрации, необходим очень сильный удар

6. on the other hand – с другой стороны

7. a beam of neutrinos – луч нейтрино

8. for that matter – поэтому

9. in the end – в конце концов

 

II. Read the following statements and say whether they are true or false:

1. In the 19th century copper wires were strung across the continents and the world was united through telegraphy. 2. The upper atmosphere does not contain regions rich in charged particles that tend to reflect the radio waves. 3. Short radio waves can go right through the ionosphere and be amplified and sent on by communications satellites. 4. Subatomic particles called neutrinos travel at the speed of light and go through the matter as though it weren't there. 5. Neutrinos can't be detected. 6. Some day neutrino telescopes will be placed all over the world. 7. Communications among worlds will be carried out through neutrino beams.



 

 

III. Answer the following questions on paragraph 4.

1. How do radio waves travel? 2. What is peculiar about the upper atmosphere of the earth? 3. What made it possible to unite the world in the 20th century without wires?

IV. Find the information dealing with the possibility of using communication satellites for sending on signals from place to place on earth.

V. In paragraph 9 find the English equivalents of the following words:

субатомный, частицы, нейтрино, перемещаться, свет, скорость, материя, луч, свинец, направление, земля.

VI. Translate paragraph 11.

VII. Read paragraph 12 and speak about the prospects of building television sets capable of converting the signals directly into light and sound.

VIII. Speak about the quickest way of communication using the information of paragraphs 12 and 13.

IX. Describe the properties of neutrinos. Write out of the text words and word combinations you need.

X. Divide text A into logical parts and find topical sentences in each part.

XI. Speak about communicating through the earth using topical sentences.

 

LESSON THREE

I. Look through the list of the English words and their Russian equivalents facilitating reading text B:

picture information – видеоинформация; teletext – телетекст, вещательная видеография; videotex – видеотекст, диалоговая видеография; frame – кадр; still frame – стоп-кадр; remote data base – удаленная база данных; to augment – увеличивать, прибавлять; terminal – оконечная станция, оконечная аппаратура, терминал; data signal – сигнал данных; line – строка, линия; magazine – кассета, карман, приемник; customer – потребитель; number pad – цифровая клавиатура; to refresh – регенерировать, обновлять, восстанавливать (информацию); data display – отображение данных или информации; информационный дисплей; subtitle – субтитр; подзаголовок; viewdata – данные изображений; transmission medium – средство передачи сообщений; database computer – вычислительная машина для работы с базами данных; public switched telephone network – коммутационная телефонная сеть общего пользования; sophisticated – сложный, усложненный; audio band – диапазон звуковых частот.

II. Skim through text В and say what the main idea of it is. (You are given 10-15 minutes).

 

Text В

Interactive Picture Information Systems

Two types of picture information systems, TELETEXT and VIDEOTEX, have come into existence1 within the past decade. Both were originally aimed at displaying still frames of information from a remote data base on a home TV set. The TV is augmented by special terminal memory and logic.

In TELETEXT, a broadcast television channel with data signals describing pictures embedded in lines in the vertical interval is used to send a magazine of frames (see Fig. below) The frames are repetitively broadcast. A typical magazine might have 100 frames, and 20 seconds are required to cycle through them. A customer of the service uses a small number pad to indicate the frame he desires to see, and the next time that frame is broadcast, its description is stored in memory in the terminal, and the frame is refreshed on the customer's TV. At least one of the frames of the magazine is an index to the remaining frames, so a customer will have knowledge of what can be selected. Provision is also made2 for mixing data display with the normal TV picture to give subtitles or news flashes.

In VIDEOTEX (originally called VIEWDATA), the transmission medium is the switched telephone network. A customer calls up a database computer and requests a frame of information to be sent to his terminal for storage and display (see Fig. 13). Table of contents frames tell a customer the numbers of frames that he can select, including more specialized table of contents frames.

                   
   
 
   
 
   
 
   
 

 

 


The principal difference between Teletext and Videotex is that videotex service uses the public switched telephone network to transmit the coded textual information. Because of this two-way communications can be used, rather than3 the one-way broadcasting of teletext. This means that a dialogue can be set up between the user and the videotex center so that sophisticated service requirements of the user may be satisfied. Another feature of the interactive type of service is that it may be used for data gathering (for which the term "ingathering" has been coined) as well as data distribution. There are many exciting new possibilities for ingathering like electronic shopping for goods and tickets and some others.

The digitally coded frames of videotex are transmitted along the telephone line in the form of modulated tone that is contained within the audio band passed by long distance telephone lines. This means that it is possible to use videotex systems in offshore vessels4 over a radio telephone channel which has, in fact, about the same bandwidth capability as a long distance telephone line. Thus, mariners would be able to receive any of the services of a videotex base, for example, weather forecasts.

Notes

1. have come into existence – появились

2. provision is also made – предусматривается также

3. rather than – а не

4. in offshore vessels – на кораблях, находящихся в открытом море

III. Find in the text answers to the following questions:

1. What types of picture information systems have come into existence? 2. What were they aimed at? 3. What is Teletext? 4. What is the transmission medium in Videotex? 5. Can Teletext and Videotex be used for electronic shopping of goods and tickets? 6. Where else can interactive picture information systems be used?

 

IV. Speak about the difference between Teletext and Videotex. Find the information in the text.


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