Text 11a Superconductivity
Superconductivity is the loss of electrical resistivity by chemical elements, compounds or alloys on being cooled to temperatures close to absolute zero. On April 8, 1911, a Dutch physicist Kamerlingh Onnes found that the electrical resistivity of a mercury wire disappeared suddenly when cooled below a temperature of 4 Kelvin.
50 years later, in 1957, American physicists presented a satisfactory theory on superconductivity and in 1972 they got the Nobel Prize for it. Many scientists made a contribution to this theory, among them Russian physicists Landau and Ginzburg. In 1986, American scientists from IBM, found a metallic ceramic compound which could become a superconductor at a temperature well above 23 K. It was difficult to believe it, but in 1987 American physicist Paul Chu produced superconductivity at 98 K in a special ceramic material. That was a sensation. Nowadays scientists found a ceramic material that works at a room temperature.
In conclusion I’d like to say that the latest world achievements in the field of superconductivity mean a revolution in science and technology.
Topic - great britain
The full name of the country is the United Kingdom of Great Britain and Northern Ireland.
The United Kingdom is situated on the British Isles. The British Isles consist of two large islands, Great Britain and Ireland, and a great number of small islands.
The island of Great Britain consists of three main parts: England, Wales and Scotland.
There are no high mountains in Great Britain. There are many beautiful lakes in the mountainous parts of the country.
Most rivers flow into the North Sea and they are not very long. The Thames is the deepest and the longest of the British rivers. Great Britain is not very rich in mineral resources; it has some deposits of coal and iron ore and vast deposits of oil and gas that were discovered in the North Sea.
In the Great Britain winters are not severely cold and summers are rarely hot.
The population of the United Kingdom is over 58 million people. The main nationalities are English, Welsh, Scottish and Irish. In Great Britain there are a lot of immigrants from former British Asian and African colonies.
Great Britain is a highly industrialized country. It is known as one of the world’s largest producers and exporters of iron and steel products, machinery and electronics, chemicals and textile, aircraft and navigation equipment. One of the main industries of the country is shipbuilding.
The main industrial centers are London, Birmingham, Manchester, Leeds, Liverpool, Glasgow and Bristol.
The capital of the country is London. The United Kingdom is a parliamentary monarchy. The Queen is the head of the state, but in practice the elected government rules it with a Prime Minister at the head. The British Parliament consists of two chambers: the House of Lords and the House of Commons.
There are three main political parties in Great Britain: the Labor, the Conservative and the Liberal. The Labor party is the ruling party nowadays.
Topic - Optical Technology
One of the most interesting developments in telecommunication is rapid progress of optical communication. It is a result of combining two great technologies of the 20th century: the laser and the fabrication of ultra-thin silicon fibers.
Optical fibers are made from glass and are usually about 120 micrometers in diameter.
It is difficult to steal information from optical fibers and they don’t ignite, so they can be used in flammable atmospheres, for example in petrochemical plants. Optical fibers are more expensive per meter than copper cables.
So, we may say that optical communication promises a considerable increase in capacity, quality, performance and reliability of the global telecommunication network.
In fact, any kind of information, such as voice, computer data, even video images, can be processed and transmitted over a single digital communication network.
Nowadays optical transmission systems are being installed between major cities of Kazakhstan at a rapid rate.