High-temperature superconductors
3_________________________________________________________________________. Then, in 1986, two European scientists working for IBM, discovered a ceramic cuprate (a material containing copper and oxygen) that could became a superconductor at much higher temperatures (−238°C, −396°F, or 35K). Other scientists have since found materials that show superconductivity at even higher temperatures and the record is currently held by a material called mercury thallium (таллий) barium (барий) calcium (кальций) copper oxide, which superconducts at −135°C (−211°F or 138K) and was patented by Korean scientists in 1996
4 _________________________________________________________________________ The original superconductors needed temperatures within a whisker of *absolute zero—and you can reach those only by cooling materials using an expensive coolant gas such as liquid helium. But the high-temperature superconductors (that's relatively high, not absolutely high—remember we're still well below minus 100 Celsius and minus 200 Fahrenheit!) can be cooled using liquid nitrogen instead, which is about 10 times cheaper to produce. A lot of applications that weren't economic suddenly became a whole lot more practical when high-temperature superconductors were discovered. 5______________________________________________________________
.
* IDM be, come etc. within a whisker of sth/doing sth – to almost do sth
41. Five sentences have been removed from the article. Choose from the sentences a)-e) the one which fits each gap (1-5). There is one sentence you do not need.
a) But if you had to cool large parts of the plant and all the transmission wires to absolute zero, you’d probably waste far more energy doing that than you’d ever save from having no resistance in the cables.
b) The ongoing drive to discover materials that superconduct at more convenient temperatures may yet make Onnes’s discovery a part of our everyday life.
c) The discovery of so-called high-temperature superconductors moved research on enormously.
d) For many years, scientists assumed superconductivity could happen only at very low temperatures.
e) The combination of both effects –the expulsion of magnetic fields and zero electrical resistance – is exactly a superconductor.
f) Each different material becomes a superconductor at a slightly different temperature (known as its critical temperature or Tc)
42. Read the article again. Are the statements true (T), false (F) or is the information
not given (NG)?
1 Most of the physical properties of superconductors vary from material to material, such as the heat capacity and the critical temperature, critical field, and critical current density at which superconductivity is destroyed
2 The simplest method to measure the electrical resistance of a sample of some material is to place it in an electrical circuit in series with a current source and measure the resulting voltage across the sample. If the voltage is zero, this means that the resistance is zero.
3 Until 1986, physicists had believed that BCS theory forbade superconductivity at temperatures above 30 K.
4 Since about 1993, the highest-temperature superconductor has been a ceramic material consisting of mercury, barium, calcium, copper and oxygen with Tc = 138 K.
5 In 1950s and 1960s, superconductors were used to build experimental digital computers using cryotron switches.
6 The idea of a power plant that gets electricity to your home down superconducting wires is brilliant: it would save huge amounts of wasted energy.
7 Practically all materials show superconductivity at temperatures close to absolute zero.
8 In 2015 hydrogen sulfide (H2S) has been observed to exhibit superconductivity at below 203 K but at extremely high pressures – around 150 gigapascals.
43. Make the words negative by adding the correct prefix.
un- dis- im- non- mis- ir- in-
-apply -convenient -continue
-integrate -sufficient -spelling
-practical -satisfactory -regular
-productive -satisfaction -connect
-advantage -believable -likely
44. Work in pairs and complete the information. Use the words below in the correct form. You need to use some words more than once.
lose conductor superconductor discover conductive
resistance mercury cool below superconductive
When an electric current is passed through a conductor some of the energy ______ in the form of heat and light. The amount of energy lost varies depending on the individual material’s electrical _________. Some materials, like copper and gold, are great _______ of electricity and have very low ________. Scientists __________that the colder these materials are the more ________ they become. But no matter how cold you make copper or gold, it will always show some electrical ___________. Mercury, however, is different. In 1911, when scientists _______ a sample of ________to 4.2 degrees above absolute zero, its _______abruptly disappeared: the first _________ was discovered. Gradually, more and more superconductive materials have been found that show zero electrical resistance _______a certain critical temperature. When _________ is zero, electricity is conducted perfectly, without any loss and a current can theoretically flow in a closed loop for ever. This has been demonstrated by scientists who have sustained electrical currents in superconductive rings for years without any measurable depreciation of energy and it doesn’t end there; not only do ______________have absolutely zero________ they also don’t like to let magnetic fields to pass through.
45. Watch the first part of the video “Superconductors” (1:08) and check your answers
46. Watch the second part of the video. “Superconductors” Then complete the dialogues and present them to the class
Student A: -What materials are known as high-temperature superconductors?
Student B - I suppose materials that ____________________________________________
- But still, always having to have liquid nitrogen at hand is _________________
- Well, it is the goal for scientists to create a material that is________________
If we had _______________________________________
we’d be able to power devices using much less power; none of the
energy would be lost as heat, changing the way that electronic devices are
designed and built.
Student A: - Have you seen the Meissner effect in action with science experiments?
Student B: - Yes, I’ve seen the video.
- Could you describe it?
- I’ll try. A __________is put on top of a _______________________and
___________ temperature nothing really special happens, but when the material
is _____________to its critical temperature the Meissner effect kicks in, causing
the_______________ as if by magic..
Student A: - We can’t forget that superconductors have to be kept at ___________________
________________ in order to function properly.
Student B: - And this is the main factor limiting the _________________________________
- Fortunately, scientists have been busy finding and creating materials that ______
_________________ at higher and higher temperatures.
Study the table
| either | neither | |
| союз | -…or…либо…-либо… или…или | -…nor…-ни…, ни… |
| местоимение | любой (из двух), кто-нибудь | никакой (из двух), никто |
| наречие | тоже, также | тоже не, также не |
I like milk. – Me too. (Я люблю молоко. Я тоже)
I don’t like milk. – Me neither. (Я не люблю молоко. – Я тоже)
I don’t like juice. – I don’t like juice either. (Я не люблю сок. – Я тоже не люблю сок.) Или же Neither do I.
Either you do this work just now or I’ll tell your parents.
They want to go either to France or to Italy for summer holidays.
You can have neither juice nor ice cream before dinner.
She eats neither fish nor meat.
47. Give short answers
0.I don’t eat porridge (Mary) – Neither does Mary.
1 I cannot understand him. (we)
2 We are not from London. (I)
3 I didn’t go to the movie. (Nick)
4 I will never talk to him. (my Mum)
5 He hasn’t got any brothers. (my friend)
6 I don’t enjoy this film. (we)
7 She isn’t going to Spain. (he)
8 My friend doesn’t like to play football. (I)
48. Complete the sentences below
11 She can’t ride a horse. I can’t ride them …
2 I’ve never been to China. – Me…
3 I can’t understand that language. I can’t understand it …
4 I speak …French …Spanish.
5 You can go … to Japan … to Vietnam.
6 Ann won’t go to the theatre tomorrow. Her brother won’t to go there …
7 Which pen can I take? …of them.
8… of the possible ways is simple
49. Translate the sentences into English
1 Мы спросили их обоих, но никто из них не знает ее адреса.
2 Он жил в Милане и в Мадриде, но ему не понравился ни один из городов.
3 Никто из них не пригласил меня, поэтому я с ними туда не ходил.
4 Мы не можем встретиться ни сегодня, ни завтра. Я очень занят.
5 Я попросил двух друзей помочь мне, но никто из них не смог приехать.
6 Ты можешь взять любую книгу, какую хочешь.
7 Ни один из нас не смог закончить свою статью, поскольку было недостаточно времени.
8 Ты можешь позвонить мне домой или в офис.
50. Make up dialogues, using neither, either, neither…nor, either …or. Guide the situations given below
You are in a new (unknown to you) district of a large city looking for your friend’s address. The houses around you seem very alike. You ask a passer-by to help you find the place.
A stranger comes to you and asks you the way to the nearest railway station. You give him the necessary directions.
51. Work in pairs. Complete the dialogue with neither, either, or
Customer: What credit cards do you take?
Cashier: Amex ____ Visa, _____ one is fine.
Customer: I have Amex (American Express).
Cashier: Okay, I need ______a license ______ photo I.D.
Customer: I have ________ with me.
Cashier: Sorry, I can’t take Amex without a photo I.D.
Customer: I don’t know what I did with my license, I probably left it at home or misplaced it
somewhere. ________way, I must find it.
Cashier: Do you still want to take these two items?
Customer: Sorry, I don’t have enough cash for______ of the two.