Добавил:
Upload Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз: Предмет: Файл:
English_for_Students_of_Chemistry.doc
Скачиваний:
243
Добавлен:
23.02.2015
Размер:
1.07 Mб
Скачать

Text 1: Radioactivity

The discovery of natural radioactivity by the French researcher Henri Becquerel ushered in a new era in science and technology. This phenomenon is based on the principle that substances occurring in nature, such as uranium and radium, are transformed into other chemical elements, independently of influences from outside, emitting different kinds of radiations which blacken a photographic plate as this is done by the rays of light.

In the decades following this discovery thousands of scientists in many countries of the world have systematically investigated the essence and the application of radioactivity and of the radiation emitted by radioactive nuclides.

The basic practical and theoretical work done by the Curies, the work by E. Rutherford who achieved an artificial nuclear transformation, the development of apparatus for the detection of radioactive nuclides by Geiger and Muller, the discovery of neutron by the English physicist J. Chadwick, the discovery of the artificial radioactivity by the Curies and the discoveries of some other scientists are the milestones in the history of radioactivity.

The field of application of radioactive nuclides in chemistry, physics, biology, agriculture, medicine and industry has rapidly expanded. One of the most interesting fields of applications of radioactivity is the determination of the age of carbonaceous materials, that is materials containing carbon, by measurement of their radioactivity due to carbon 14.

This technique of radiocarbon dating permits the dating of samples containing carbon with an accuracy of around 200 years.

At the present time the method involved can be applied to materials that are about 25,000 years old.

Today the range of application of radioactive nuclides comprises all branches of research work. Thus, for example, certain medical examinations call for short lived radioactive nuclides in order that the human organism should not be exposed too long a period of time to radiation, whereas a radioactive nuclide which excites the luminescent material should have a long half-life.

Investigations into the reaction mechanisms in chemistry, researches in the field of physics, the explanation of vital processes in plants, animals and man, diagnostics of diseases of the human body, the testing of metallic and ceramic materials are but a few fields of science and technology which today, 91 years after the discovery of radioactivity, cannot dispense with radioactive nuclides and the radiation emitted by them.

It should be added that a considerable number of research problems has only become soluble by the use of radioactive nuclides.

Ex. 6. Look through the text again and find the sentences where the author describes:

  • the principle of natural radioactivity

  • radioactive nuclides application

  • application of radioactive nuclides in medicine

  • the limitation of usage

Ex. 7. Think if the following statements are true or false.

  1. Natural radioactivity is based on the principle that artificially made substances can be transformed into other chemical elements.

  2. Natural radioactive elements ban blacken a photographic plate whereas artificial ones can not.

  3. Geiger was the one to invent the device of radioactive nuclides detection.

  4. One of the most interesting application of radioactive nuclides is the dating of carbon containing samples.

  5. Only a few branches of science can apply radioactive nuclides.

  6. Nowadays scientists can apply just a limited possibility of radioactive nuclide.

Ex. 8. Find in the text English equivalents of the following words and word combinations.

  1. оголосити про

  2. незалежно

  3. випромінювати

  4. затемнювати

  5. сутність

  6. виявлення

  7. штучна радіоактивність

  8. віха

  1. визначення віку за допомогою ізотопів вуглецю

  2. зразок

  3. таким чином

  4. медичні аналізи

  5. період напіврозпаду

  6. обходитися без

  7. значна кількість

  8. той, що можна вирішити

Ex. 9. Match the Ukrainian words and word combinations from the exercise above with their English equivalents.

  1. half-life

  2. detection

  3. usher in

  4. sample

  5. considerable number

  6. essence

  7. independently

  8. dispense with

  1. radiocarbon dating

  2. artificial radioactivity

  3. emit

  4. thus

  5. soluble

  6. medical examination

  7. milestone

  8. blacken

Ex. 10. Answer the following questions:

  1. Who discovered the phenomenon of radioactivity?

  2. What is the phenomenon of radioactivity based on?

  3. What are the milestones in the history of radioactivity?

  4. Where can radioactivity be applied?

  5. What is the most interesting field of applications of radioactivity?

  6. Where are radioactive nuclides applied now?

Ex. 11. Open the brackets choosing the correct forms of the Participles. Translate the sentences into Ukrainian.

1. Much could be (writing, written) about the application of nuclides. 2. Many experiments have been (carrying out, carried out) in the field of radioactivity. 3. The work (doing, done) by the scientists was of great significance. 4. Many of the above-mentioned applications of radioactive nuclides or of the radiation (emitting, emitted) by them are directly or indirectly connected with industry. 5. A mechanical method was (substituting, substituted) by a new one. 6. This type of radiation consists of a current of positively (charged, charging) particles. 7. This discovery (following, followed) by many experiments was of great use to chemists. 8. The two substances (investigating, investigated) were homogeneous. 9. The man (speaking, spoken of) was the first to discover this phenomenon.

Ex. 12. Translate the following sentences into English using Participial constructions.

  1. Деякі речовини природного походження, такі як уран або радій, можуть перетворюватись на інші хімічні елементи, випромінюючи при цьому радіацію.

  2. Робота, що була проведена Кюрі, має важливе теоретичне значення.

  3. Матеріали, що містять вуглець, можна проаналізувати для визначення віку.

  4. Через те, що деякі радіоактивні нукліди мають короткий період напіврозпаду, вони можуть використовуватись у медичних цілях.

  5. Тільки після винаходу радіоактивних нуклідів людство спромоглося вирішити значну кількість задач.

Ex. 13. Open the brackets choosing the correct forms of the Participles:

1. When (heating, having heated) this substance, one should be very careful. 2. (Investigated, having investigated, investigating) all the properties of new water, they could understand the mystery of silvery clouds. 3. The (dissolving, dissolved, having dissolved) materials may be soluble solids, liquids or gases. 4. Water (using, used, having used) in steam boilers, should be free from substances that cause corrosion. 5. (Purified, having purified, purifying) the water from the substance that cause corrosion, we can use it in steam boilers.

Ex. 14. Translate into Ukrainian paying attention to the Participles.

1. Some adsorbents may contain sufficient acid or alkali to alter the pH of the water being treated. 2. Having been compressed the air is to be cooled. 3. Having been composed of liquid particles emulsions disperse in other liquids. 4. Being used in different fields of chemistry, industry and medicine colloid chemistry becomes increasingly important. 5. When placed in a liquid, the corresponding solids will swell first and then slowly go into solution.

Ex. 15. Translate the following sentences paying attention to the meanings of the word "learn":

1. He carried out a number of experiments as he wanted to learn all the properties of the water. 2. We have learned that he teaches at the Chemico-Technological Institute. 3. The first-year students learn physics, mathematics, and some other subjects. 4. Having learned the weight of hydrogen and oxygen, the research-workers could determine the ratio of two elements. 5. If you want to investigate all the properties of this element, first of all learn its atomic weight.

Ex. 16. Before reading the text match the word and its definition

1

accelerator

A

a branch of production or manufacture

2

beam

B

direction a stream of high-speed particles

3

bombardment

C

living being with interdependent parts

4

detector

D

apparatus for imparting high speeds to charged particles

5

industry

E

place of origination

6

isotope

F

ray or shaft of light or radiation

7

organism

G

artificial radioactive isotope which can be followed through the body by the radiation it produces

8

research

H

one of two or more forms of an element differing from each other in relative atomic mass, and in nuclear but not chemical properties

9

source

I

systematic investigation and study of materials, sources, etc., in order to establish facts and reach conclusions

10

tracer

J

discoverer

Тут вы можете оставить комментарий к выбранному абзацу или сообщить об ошибке.

Оставленные комментарии видны всем.

Соседние файлы в предмете [НЕСОРТИРОВАННОЕ]