2017-12-14
754
по английскому языку для студентов всех технических специальностей ЗФ
Вариант 5
Ш семестр
I. Прочитайте и переведите текст (устно).
SMART MATERIALS
Smart – or shape memory – materials are an invention that has changed the world of engineering. There are two types of such materials: metal alloys and plastic polymers. The metal alloys were made first and they are usually an expensive mixture of titanium and nickel.
Shape memory materials are called 'smart' because they react to changes in their environment, for example:
• plastics that return to their original shape when the temperature changes; One use is in
surgery where plastic threads 'remember' the shape of a knot, react to the patient's body
temperature and make themselves into stitches.
• metal alloys that have a 'memory' and can return to their original shape. They are used in medical implants that are compressed so they can be put inside the patient's body through a small cut. The implant then expands back to its original shape. More everyday uses are for flexible spectacle frames and teeth braces, solids that darken in sunlight, like the lenses in some sunglasses.
• liquid crystals that change shape and colour. These have been used in climbing ropes that
change colour if there is too much strain and weight on them.
The future of these materials and their possible uses is limited only by human imagination. One clever idea is that if cars were made of smart metal, a minor accident could be repaired by leaving the car in the sun!
The first reported steps towards the discovery of the shape-memory effect were taken in the 1930s. The nickel-titanium alloys were first developed in 1962–1963 by the United States Naval Ordnance Laboratory. Their remarkable properties were discovered by accident. A sample that was bent out of shape many times was presented at a laboratory management meeting. One of the technical directors decided to see what would happen if the sample was subjected to heat and held his pipe lighter underneath it. To everyone's amazement the sample stretched back to its original shape.
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II. Выберите правильный вариант ответа на вопросы по тексту.
1. What time could smart materials be referred to?
a) the invention of the 19th century
b) the invention of our time
c) the old Persian technology
2. What characteristics do the smart materials exhibit?
a) dissipating after heating
b) changing the melting point
c) returning to their original form
3. When were the first nickel-titanium alloys developed?
a) 1930s
b) 1962-1963
c) the 21st century
III. Закончите предложение по содержанию прочитанного текста.
4. Smart materials …
a) are a new development in engineering.
b) used are very old.
c) are manufactured everywhere.
5. Materials that react to changes in environment are …
а) called alloys.
b) only plastics.
c) called smart materials.
6. There …
a) is need in smart materials in medicine.
b) are three types of smart materials.
c) are experiments with aluminum-titanium alloys.
7. One of the laboratory directors …
a) broke the sample.
b) decided to heat the sample.
c) exposed the sample to light.
8. After heating, the sample …
a) returned to its original shape.
b) did not change the form.
c) evaporated.
