Boaz Almog "levitates" a superconductor

772,929 views ・ 2012-07-02

TED


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00:00
Translator: Morton Bast Reviewer: Thu-Huong Ha
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Prevoditelj: SIBELA KESAC Recezent: Suzana Baric
00:25
The phenomenon you saw here for a brief moment
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Fenomen koji ste vidjeli, u jednom kratkom trenutku
00:29
is called quantum levitation and quantum locking.
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zove se kvantna levitacija i kvantno zaključavanje.
00:35
And the object that was levitating here
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Objekt koji je levitirao
00:39
is called a superconductor.
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zove se supravodič.
00:41
Superconductivity is a quantum state of matter,
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Supravodljivost je kvantno stanje stvari,
00:47
and it occurs only below a certain critical temperature.
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koje se događa samo ispod određenih temperatura.
00:51
Now, it's quite an old phenomenon;
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Zapravo je to fenomen koji već dugo poznajemo.
00:53
it was discovered 100 years ago.
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Otkriven je prije stotinu godina.
00:55
However, only recently,
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Međutim, tek odnedavno,
00:57
due to several technological advancements,
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zahvaljujući tehnološkom napretku,
01:00
we are now able to demonstrate to you
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možemo vam demonstrirati
01:02
quantum levitation and quantum locking.
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kvantnu levitaciju i kvantno zaključavanje.
01:06
So, a superconductor is defined by two properties.
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Dakle, supravodič je određen dvama svojstvima.
01:12
The first is zero electrical resistance,
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Prvo svojstvo je odsustvo električnog otpora,
01:15
and the second is the expulsion of a magnetic field from the interior of the superconductor.
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a drugo je izbacivanje magnetskog polja iz unutrašnjosti supravodiča.
01:22
That sounds complicated, right?
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Zvuči kompilcirano, zar ne?
01:25
But what is electrical resistance?
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No, što je električni otpor?
01:28
So, electricity is the flow of electrons inside a material.
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Elektricitet je protok elektrona unutar materijala.
01:34
And these electrons, while flowing,
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I ti elektroni se u svom kretanju
01:38
they collide with the atoms, and in these collisions
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sudaraju s atomima, i u tim sudarima
01:40
they lose a certain amount of energy.
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gube određenu količinu energije.
01:42
And they dissipate this energy in the form of heat, and you know that effect.
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Ta se energija rasipa u vidu zagrijavanja, i to vam je poznato.
01:48
However, inside a superconductor there are no collisions,
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Međutim, unutar supravodiča nema sudaranja
01:54
so there is no energy dissipation.
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i stoga nema rasipanja energije.
01:59
It's quite remarkable. Think about it.
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To je zaista izvanredno. Razmislite o tome.
02:02
In classical physics, there is always some friction, some energy loss.
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U klasičnoj fizici, uvijek imamo trenje, uvijek se gubi nešto energije.
02:07
But not here, because it is a quantum effect.
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Ali, ne i ovdje, zbog toga što je riječ o kvantnom efektu.
02:11
But that's not all, because superconductors don't like magnetic fields.
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Ali to nije sve, zato što supravodiči ne vole magnetna polja.
02:19
So a superconductor will try to expel magnetic field from the inside,
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Zato supravodiči nastoje izbaciti magnetno polje iznutra,
02:24
and it has the means to do that by circulating currents.
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a to rade uz pomoć kružnih struja.
02:30
Now, the combination of both effects --
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Kombinacija oba efekta --
02:33
the expulsion of magnetic fields and zero electrical resistance --
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izbacivanje magnetnog polja i izostanak električnog otpora
02:39
is exactly a superconductor.
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jest supravodič.
02:42
But the picture isn't always perfect, as we all know,
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No, kako to biva, slika nije uvijek savršena
02:46
and sometimes strands of magnetic field remain inside the superconductor.
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i ponekad silnice magnetnog polja ostaju u supravodiču.
02:54
Now, under proper conditions, which we have here,
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Sada, u odgovarajućim uvjetima, kakve imamo ovdje,
02:57
these strands of magnetic field can be trapped inside the superconductor.
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silnice magnetnog polja mogu ostati zarobljene unutar supravodiča.
03:02
And these strands of magnetic field inside the superconductor,
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A te silnice unutar supravodiča
03:09
they come in discrete quantities.
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dolaze u malim količinama.
03:12
Why? Because it is a quantum phenomenon. It's quantum physics.
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Zašto? Zato što je to kvantni fenomen. Kvantna fizika.
03:15
And it turns out that they behave like quantum particles.
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I ispada da se one ponašaju poput kvantnih čestica.
03:19
In this movie here, you can see how they flow one by one discretely.
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U ovom ovdje filmu možete vidjeti kako se diskretno kreću jedna po jedna.
03:25
This is strands of magnetic field. These are not particles,
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Ovo su silnice magnetnog polja. Ovo nisu čestice,
03:28
but they behave like particles.
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ali se ponašaju poput čestica.
03:33
So, this is why we call this effect quantum levitation and quantum locking.
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Dakle, zbog toga se fenomen zove kvantna levitacija i kvantno zaključavanje.
03:37
But what happens to the superconductor when we put it inside a magnetic field?
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No, što se dešava sa supravodičem kada ga stavimo unutar magnetnog polja?
03:43
Well, first there are strands of magnetic field left inside,
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Pa, imamo silnice magnetnog polja koje su ostale unutra,
03:48
but now the superconductor doesn't like them moving around,
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ali sada supravodiču više ne odgovara da se one kreću naokolo
03:52
because their movements dissipate energy,
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jer njihovo kretanje rasipa energiju
03:55
which breaks the superconductivity state.
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i to prekida stanje supravodljivosti.
03:58
So what it actually does, it locks these strands,
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Tako da zapravo da zaključava te silnice,
04:02
which are called fluxons, and it locks these fluxons in place.
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koje se zovu fluksoni. Zaključava fluksone u mjestu.
04:08
And by doing that, what it actually does is locking itself in place.
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Na taj način on sam sebe zapravo zaključava u mjestu.
04:15
Why? Because any movement of the superconductor will change their place,
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Zašto? Zato što svaki pokret supravodiča mijenja mjesto silnica
04:24
will change their configuration.
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i njihovu konfiguraciju.
04:26
So we get quantum locking. And let me show you how this works.
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I tako dobivamo kvantno zaključavanje. Pokazat ću vam kako to funkcionira.
04:31
I have here a superconductor, which I wrapped up so it'd stay cold long enough.
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Ovdje imam supravodič koji sam umotao kako bi dovoljno dugo ostao hladan.
04:37
And when I place it on top of a regular magnet,
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I kada ga stavim na običan magnet,
04:41
it just stays locked in midair.
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on ostane zaključan u zraku.
04:45
(Applause)
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(Pljesak)
04:49
Now, this is not just levitation. It's not just repulsion.
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Pazite, ne radi se o levitaciji. Nije to obično odbijanje.
04:53
I can rearrange the fluxons, and it will be locked in this new configuration.
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Mogu prerasporediti fluksone i bit će zaključan u ovoj novoj konfiguraciji.
04:58
Like this, or move it slightly to the right or to the left.
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Na primjer, ovako. Ili ga mogu pomaknuti malo lijevo ili desno.
05:02
So, this is quantum locking -- actually locking -- three-dimensional locking of the superconductor.
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Dakle, ovo je kvantno zaključavanje -- stvarno zaključavanje -- trodimenzionalno zaključavanje supravodiča.
05:10
Of course, I can turn it upside down,
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Naravno, može se okrenuti i naglavačke
05:12
and it will remain locked.
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i ostat će zaključan.
05:15
Now, now that we understand that this so-called levitation is actually locking,
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Sada kada razumijemo da je tzv. levitacija zapravo zaključavanje,
05:24
Yeah, we understand that.
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da, to smo shvatili.
05:29
You won't be surprised to hear that if I take this circular magnet,
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Neće vas iznenaditi ako vam kažem da će, ako uzmem ovaj kružni magnet
05:33
in which the magnetic field is the same all around,
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u kojem je magnetno polje jednako na svim djelovima,
05:37
the superconductor will be able to freely rotate around the axis of the magnet.
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supravodič slobodno kružiti oko osi magneta.
05:43
Why? Because as long as it rotates, the locking is maintained.
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Zašto? Zato što dokle god rotira, održava se zaključavanje.
05:49
You see? I can adjust and I can rotate the superconductor.
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Vidite? Mogu namjestiti i rotirati supravodič.
05:55
We have frictionless motion. It is still levitating, but can move freely all around.
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Imamo kretanje bez trenja. Još uvijek levitira, ali se može slobodno kretati uokolo.
06:01
So, we have quantum locking and we can levitate it on top of this magnet.
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Dakle, imamo kvantno zaključavanje i mogućnost levitacije na vrhu magneta.
06:11
But how many fluxons, how many magnetic strands are there in a single disk like this?
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No, koliko fluksona, koliko magnetnih silnica imamo u jednom ovakvom disku?
06:17
Well, we can calculate it, and it turns out, quite a lot.
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Pa, možemo to izračunati i ispada da ih je mnogo.
06:20
One hundred billion strands of magnetic field inside this three-inch disk.
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Stotinu milijardi silnica magnetnog polja nalazi se unutar jednog ovakvog diska veličine 7,6 cm.
06:27
But that's not the amazing part yet, because there is something I haven't told you yet.
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Ali, to još nije nevjerojatan dio priče, zato što postoji nešto što vam još nisam rekao.
06:32
And, yeah, the amazing part is that this superconductor that you see here
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Da, da, nevjerojatan dio priče je taj da je supravodič kojeg ovdje vidite
06:37
is only half a micron thick. It's extremely thin.
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debeo samo pola mikrona. Izuzetno je tanak.
06:45
And this extremely thin layer is able to levitate more than 70,000 times its own weight.
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I taj nevjerojatno tanki sloj može držati nešto 70,000 puta teže od vlastite težine.
06:54
It's a remarkable effect. It's very strong.
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To je nevjerojatan efekt. Izuzetno snažan.
07:00
Now, I can extend this circular magnet,
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Sada, mogu proširiti ovaj kružni magnet
07:04
and make whatever track I want.
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i napraviti kakvu god traku želim.
07:08
For example, I can make a large circular rail here.
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Na primjer, mogu napraviti veliku kružnu traku ovdje.
07:12
And when I place the superconducting disk on top of this rail,
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I kada na traku stavim supravodljivi disk,
07:19
it moves freely.
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on se slobodno kreće.
07:23
(Applause)
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(Pljesak)
07:33
And again, that's not all. I can adjust its position like this, and rotate,
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Ali opet, to nije sve, mogu ga namjestiti ovako i rotirati
07:37
and it freely moves in this new position.
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i on se slobodno kreće u tom novom položaju.
07:44
And I can even try a new thing; let's try it for the first time.
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I možemo probati i jednu novu stvar; probajmo to po prvi put.
07:48
I can take this disk and put it here,
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Mogu uzeti ovaj disk, staviti ga ovdje,
07:54
and while it stays here -- don't move --
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i dok je tu -- ne miči se --
07:57
I will try to rotate the track,
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probat ću zarotirati traku,
08:04
and hopefully, if I did it correctly,
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i nadati se, ako sam to dobro učinio,
08:06
it stays suspended.
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da će tu ostati.
08:08
(Applause)
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(Pljesak)
08:18
You see, it's quantum locking, not levitation.
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Vidite, radi se o kvantnom zaključavanju, ne o levitaciji.
08:25
Now, while I'll let it circulate for a little more,
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Sada, pustit ćemo ga da još malo kruži,
08:29
let me tell you a little bit about superconductors.
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a ja ću vam reći nešto o supravodičima.
08:32
Now -- (Laughter) --
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Sada-- (Smijeh) --
08:38
So we now know that we are able to transfer enormous amount of currents inside superconductors,
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Sada znamo da možemo prenijeti ogromne količine struje unutar saupravodiča
08:45
so we can use them to produce strong magnetic fields,
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pa ih možemo koristiti da bismo stvorili jaka magnetna polja,
08:50
such as needed in MRI machines, particle accelerators and so on.
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koja su potrebna kod MRI uređaja, ubrzivača čestica, itd.
08:55
But we can also store energy using superconductors,
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Ali unutar supravodiča možemo i spremiti energiju,
09:00
because we have no dissipation.
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zato što nema rasipanja.
09:02
And we could also produce power cables, to transfer enormous amounts of current between power stations.
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I možemo proizvesti kablove za prijenos ogromnih količina struje između elektrana.
09:09
Imagine you could back up a single power station with a single superconducting cable.
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Zamislite da možete podržati cijelu elektranu sa samo jednim supravodljivim kablom.
09:18
But what is the future of quantum levitation and quantum locking?
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No što je budućnost kvantne levitacije i kvantnog zaključavanja?
09:23
Well, let me answer this simple question by giving you an example.
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Pa, odgovorit ću vam na ovo jednostavno pitanje jednim primjerom.
09:30
Imagine you would have a disk similar to the one I have here in my hand,
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Zamislite da imate disk koji je nalik ovom ovdje kojeg imam u ruci,
09:36
three-inch diameter, with a single difference.
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7,6 centimetara u promjeru, sa samo jednom razlikom.
09:40
The superconducting layer, instead of being half a micron thin,
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Supravodljivi sloj, umjesto debljine jednog mikrona,
09:45
being two millimeters thin, quite thin.
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bude debljine dva milimetra, i dalje jako tanak.
09:48
This two-millimeter-thin superconducting layer could hold 1,000 kilograms, a small car, in my hand.
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Takav supravodljivi sloj od dva milimetra može držati 1.000 kilograma, manji auto, u mojoj ruci.
09:59
Amazing. Thank you.
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Zadivljujuće. Hvala vam.
10:02
(Applause)
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(Pljesak)
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