5. With the discovery of... superconductivity has become almost practical.
6. As a coolant liquid helium can be replaced by ... .
7. If the technology of superconductors is improved, they could be turned into practical devices such as....
• Look through the passage and answer the following questions.
1. What is superconductivity?
2. How old is the discovery of superconductivity?
3. What conditions enable some metals to become superconducting?
4. How can these conditions be provided?
5. Why has superconductivity not become widely used in practice?
6. What laterdevelopmcnts have brought superconductivity into the range of practical use?
7. What properties make liquid nitrogen more attractive as a coolant than liquid helium?
8. What fields of superconductor application could you name?
CLASS WORK
READING (14B)
• Skim the passage carefully (3 min), define the main idea of the passage and give a headline to it.
In terms of the social impact superconductivity could well be the breakthrough of the 1980s in the sense that the transistor was the breakthrough ofthe 1950s. Indeed, scientists hardly know where to start in describing the bonanza that superconductors could yield.
Take the transmission of electricity, for example. As much as 20% ofthe energy sent through high-tension lines is now lost in the form of heat generated as the current encounters resistance in the copper wire. If the electricity could be sent through superconducting cable, however, not a kilowatt-second of energy would be lost, thus saving the utilities, and presumably consumers, billions of dollars. Furthermore, at least in theory, all of a large city's electrical energy needs could be supplied through a handful of underground cables.
Elimination of heat caused by electrical resistance could have ^profound effect on the design and performance of computers. In their efforts to produce smaller and faster computers, designers try to cram more and more circuits into chips and ever more chips into a tiny space. But they are limited in their scaling down endeavors by heat: even the tiny currents in computer circuits generate enough cumulative heat to damage components if they are too tightly packed. Today's personal computers could not operate without vents or internal fans to dissipate the heat. Now, with practical superconducting circuitry on the horizon, computer designers may soon see the way clear for even more remarkable miniturization.
In still othcrapplications, the intense magnetic fields that might some day be generated by the new superconductors should benefit any device that now uses electromagnctism in its operation — medical diagnostic imaging machines, magnetically levitated trains, fusion-energy generators — and will undoubtedely spawn a host of new machines. Electric motors could increase in power and shrink in size.
• Explain how you understand the italicized words in the passage.
• Look through the passage again and choose all potential Fields of superconductor applications in practice.
• Think and say a few words about the problem as a whole.
HOMEWORK
(to be done in writing)
1. Translate into Russian.
High-temperature Superconductors
The new HTSCs arc mixed oxides that display the mechanical and physical properties of ceramics. A key to the behaviour of the new ..- 'crials appears to be the presence of planes containing copper (Cu) and • gen (O) atoms, chemically bonded to each other. The special nature of the copper-oxygen chemical bonding gives rise to materials that conduct electricity well in some directions in contrast to the majority of ceramics whic'i are electrically insulating.
The first class of high T(.' oxides discovered was based on the chemical alteration ofthe insulating ternary compound La2Cu04 by replacement of a small fraction ofthe element lanthanum (La) with the alkaline earths barium (Ba), strontium (Sr) or calcium (Ca). This substitution led to compounds with Tcs of up to 40 K. In these materials, an intimate relation between superconductivity and magnetic order is presently under intensive study and has inspired one of the many classes of theories that attempt to explain HT Superconductivity.
2. Translate into English.
1. Значительный прогресс в понимании физической основы сверхпроводимости наступил (come) в 1940-х годах.
2. Он связан с работами хорошо известных советских ученых П.Л. Капицы и Л .Д. Ландау.
3. Они разработали макроскопическую теорию сверхтекучести (superfluidity) жидкого гелия, которая возникает при температурах около абсолютного нуля.
4. Они написали большое количество научных статей по сверхпроводимости и промежуточным (intermediate) состояниям в сверхпроводниках при низких температурах.
Tt.s — critical temperatures
UNIT FIFTEEN
GRAMMAR: REVISION
• Provide answers to the following questions. Use the words in brackets. Follow the model.
Model: What problems do they discuss? (A highly important...)
A highly important problem has just been discussed by them.