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SEMICONDUCTORS IN MODERN TECHNOLOGY

During the past several decades technology has passed 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 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 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 modem electronic devices for examp1, in transistors, thermocouples, non-linear resistors and so on.

This special place occupied by semiconductors in modem 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 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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ROBOTS MOVE IN

Imagine the real working conditions for a human operator at, for example, transfer of a hot-formed glass tube, the removal of hot metal die castings or plastics injection. The environmental temperature is above 50 and the melting furnaces produce direct and unbearable heat radiation. This kind of job is very difficult, exhausting, monotonous and unpleasant. In the case of machining radioactive or toxic material the work becomes highly dangerous for a man's life.

The necessity of some form of automated handling processes became obvious. So robots appeared on the scene with their high safety and reliability level.

We are now surrounded by robots, big ones, little ones, and medium-sized ones. They serve us in thousands of ways every day.

You can find robots practically anywhere you look. In factories there are giant robots. They pick up great amounts of raw materials and pass them to other robots to press, stamp and shape the raw materials into a wide variety of things.

According to available data, the industry in our country receives annually thousands of robots of different types and purposes. Today robotic systems, lines and modules are already operating at the leading plants of the motor, electrical engineering, watch-making, machine-tool industries, etc.

 

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Oil in the sea

The sea is full of bacteria, plants and animals which eat waste. It can clean itself if we do not use it as a dump. But if we pump too much waste in the sea, the bacteria, plants and animals cannot recycle it quickly enough and the water gets polluted.

When you use a toilet, the waste goes into a sewer. But where does it go after that? All over the world, sewers dump waste into the sea. The sea washes the waste onto the beaches and pollutes them.

The Mediterranean is one of the most polluted seas in the world. There is land nearly all around it, so the waste has nowhere to go. Many big towns empty their sewers into the sea. It is not safe to swim in parts of the Mediterranean, and many beaches are polluted.

Chemicals from farms and factories get into rivers; and the rivers carry the waste to the sea. The chemicals get into the food chain and poison the fish. Ships dump their waste at sea and pollute the beaches.

The worst kind of sea pollution is an oil spill. Oil is black and dirty and contains toxic chemicals. If you spill oil at sea, it makes an oil slick on top of the water. Air cannot get to the plants and animals under the water. We spill a lot of oil into the sea every year, from ships and from oil refineries. Those oil spills were accidental, but the worst oil pollution in the world was deliberate. In the Gulf War in 1991, oil was spilled deliberately. Oil wells burned and millions of tonnes of oil went into the sea. There were fifty-kilometre oil slicks. Oil also spilled onto the ground. There were lakes of burning oil everywhere. The oil went down under the ground and polluted the water in underground wells.

The pollution was terrible. Electric street lights burned all day in Kuwait because of the smoke and smog from burning oil. Black and dirty rain fell on the Himalayan mountains, thousands of kilometres away. Many years after the war, people are still trying to clean everything up.

. , 䳺-. .

1. The radar has been used for the automatic control of ground-transport.

2. Today plastics are being widely used instead of metals.

3. The construction of the dam has been completed this month.

4. The alloys were experimented upon in our lab.

. , it, that, one.

1. It is the number of electrons within the atom that determines the properties of a substance.

2. The territory of Kyiv is less than that of London.

3. In London one must get used to the left-side traffic

. , .

1. The hostel our students live in is situated not far from the metro station.

2. I think he has made a mistake in his calculations.

IV. . , ᒺ ᒺ .

1. The Sun and stars are proved to be able to produce great quantities of energy by means of certain nuclear reactions.

2. For the experiment we need several electrical devices to be connected in series.

3. Lasers are known to have found application in medicine.

V. . 䳺 .

1. Measurements of solar radiation reaching the Earth each day make it possible to calculate the surface temperature of the Sun.

2. Having built a new automobile plant, we increase the output of cars and buses.

3. Knowledge being the most valuable wealth of our times, the information theory became of great importance for the national economy.

VI. . .

1. If the gathered data had been presented in time, the results of the experiments would have been different.

2. If you had answered six questions in the competition, you would have won the first prize.

3. It would be impossible to carry on a careful study of the process without the new device.

VII. . .

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SUN-DRIVEN ENGINE

It is common knowledge that certain metals and their alloys are attracted by a magnet. After heating this property vanishes: it is restored after cooling down. A new magneto-heat engine works on this principle. This invention relates to devices which transform thermal power, for instance, the power of the sun rays, into a mechanical power of rotation.

We know solar power is inexhaustible and its use does not harm the environment. That's why such importance is attached to the devices which make it possible to apply the idea of direct use of solar power, transforming it into mechanical forms of power. The development of an engine directly driven by heat source such as solar power, makes it possible to simplify and make power generation considerably cheaper, in comparison to the existing thermal engines we use today.

The rotor of the new engine is made of an alloy that loses its magnetic properties already at 100C. If the rotor is heated on one side, the cold side of the rotor will turn toward the magnet. Since heating continues, the rotor goes on rotating, too. This solar power can be used as a source of heat in this case. The magneto-heat engine can drive pumps in waterless districts, can also be widely used for watering greenery in cities and settlements.

By using thermomagnetic alloys it is possible to develop a lot of automatic devices, for example, solar clocks, thermometers, etc. Mention should be made that these devices can withstand extreme temperatures. To organize the production of the necessary alloys is simple as there is no need for rare materials or complex technology.

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