{"id":55195,"date":"2020-01-15T00:00:00","date_gmt":"2020-01-14T21:00:00","guid":{"rendered":"https:\/\/prohoster.info\/blog\/blog_prohoster\/velikaya-teoriya-snezhinok"},"modified":"2020-02-18T14:03:17","modified_gmt":"2020-02-18T11:03:17","slug":"velikaya-teoriya-snezhinok","status":"publish","type":"post","link":"https:\/\/prohoster.info\/cs\/blog\/news\/velikaya-teoriya-snezhinok","title":{"rendered":"Velk\u00e1 teorie sn\u011bhov\u00fdch vlo\u010dek","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"

\"Velk\u00e1
\nTato zima je v centr\u00e1ln\u00ed \u010d\u00e1sti Ruska m\u00e1lo sn\u011bhov\u00e1. Kdesi samoz\u0159ejm\u011b napadl, ale v lednu jsme mohli o\u010dek\u00e1vat n\u011bjak\u00e9 v\u00edce mraziv\u00e9 a sn\u011bhov\u00e9 po\u010das\u00ed. Smutn\u00e1 \u0161edivost a nep\u0159\u00edjemn\u00e1 b\u0159e\u010dka br\u00e1n\u00ed pocit\u016fm radosti z obvykl\u00fdch zimn\u00edch radov\u00e1nek. Proto Cloud4Y nab\u00edz\u00ed, abychom do na\u0161eho \u017eivota p\u0159idali trochu sn\u011bhu a promluvili o\u2026 sn\u011bhov\u00fdch vlo\u010dk\u00e1ch.<\/i><\/a><\/noindex><\/p>\n

P\u0159edpokl\u00e1d\u00e1 se, \u017ee sn\u011bhov\u00e9 vlo\u010dky jsou pouze dvou typ\u016f. Jeden ze v\u011bdc\u016f, kter\u00e9ho ob\u010das naz\u00fdvaj\u00ed \"otcem\" fyziky sn\u011bhov\u00fdch vlo\u010dek, p\u0159i\u0161el s novou teori\u00ed, kter\u00e1 vysv\u011btluje d\u016fvod tohoto jevu. Kenneth Libbrecht<\/a><\/noindex> je fascinuj\u00edc\u00ed \u010dlov\u011bk, kter\u00fd je ochoten opustit slunnou Ji\u017en\u00ed Kalifornii uprost\u0159ed zimy, aby se dostal do Fairbanksu na Alja\u0161ce, obl\u00e9kl si teplou bundu a usadil se na promrzl\u00e9 louce s kamerou a kusem polystyrenov\u00e9 desky v rukou.<\/p>\n

Pro\u010d? Hled\u00e1 nejjasn\u011bj\u0161\u00ed, nejtexturovan\u011bj\u0161\u00ed a nejkr\u00e1sn\u011bj\u0161\u00ed sn\u011bhov\u00e9 vlo\u010dky, kter\u00e9 p\u0159\u00edroda dok\u00e1\u017ee vytvo\u0159it. Podle jeho slov se nejzaj\u00edmav\u011bj\u0161\u00ed vzorky tvo\u0159\u00ed na nejchladn\u011bj\u0161\u00edch m\u00edstech \u2014 na proslul\u00e9m Fairbanksu a ve zasn\u011b\u017een\u00e9 severn\u00ed \u010d\u00e1sti New Yorku. Nejlep\u0161\u00ed sn\u00edh, kter\u00fd Kenneth kdy vid\u011bl, padal v Cochra na severov\u00fdchod\u011b Ontaria, kde slab\u00fd v\u00edtr rozt\u00e1\u010del sn\u011bhov\u00e9 vlo\u010dky padaj\u00edc\u00ed z nebe.<\/p>\n

Okouzlen p\u0159\u00edrodou, Libbrecht s hou\u017eevnatost\u00ed archeologa zkoum\u00e1 svou polystyrenovou desku. Pokud je tam n\u011bco zaj\u00edmav\u00e9ho, jeho pohled se na to ur\u010dit\u011b upne. Pokud ne \u2014 sn\u00edh je smeten z desky a v\u0161e za\u010d\u00edn\u00e1 znovu. A to trv\u00e1 hodiny.<\/p>\n

Libbrecht je fyzik. Z podivn\u00e9ho souhry okolnost\u00ed se jeho laborato\u0159 na Kalifornsk\u00e9m technologick\u00e9m institutu zab\u00fdv\u00e1 v\u00fdzkumem vnit\u0159n\u00ed struktury Slunce a dokonce vyvinula modern\u00ed p\u0159\u00edstroje pro detekci gravita\u010dn\u00edch vln. Ale v posledn\u00edch 20 letech byla skute\u010dnou v\u00e1\u0161n\u00ed Libbrechta sn\u00edh \u2014 nejen jeho vzhled, ale i to, co zp\u016fsobuje, \u017ee vypad\u00e1 tak, jak vypad\u00e1. \"Ot\u00e1zka, jak\u00e9 objekty padaj\u00ed z nebe, jak se to d\u011bje a pro\u010d vypadaj\u00ed takto, m\u011b neust\u00e1le tr\u00e1p\u00ed,\" p\u0159izn\u00e1v\u00e1 Kenneth.<\/p>\n

\"Velk\u00e1
\n
\nDlouho bylo pro fyziky dostate\u010dn\u00e9 v\u011bd\u011bt, \u017ee mezi mnoha drobn\u00fdmi sn\u011bhov\u00fdmi krystaly lze rozli\u0161it dva p\u0159evl\u00e1daj\u00edc\u00ed typy. Jeden z nich je ploch\u00e1 hv\u011bzda se \u0161esti nebo dvan\u00e1cti paprsky, z nich\u017e ka\u017ed\u00fd je zdoben \u00fachvatn\u011b kr\u00e1sn\u00fdmi krajkami. Druh\u00fd p\u0159ipom\u00edn\u00e1 jakousi miniaturu sloupu, n\u011bkdy stla\u010den\u00e9ho mezi ploch\u00fdmi \"v\u00ed\u010dky\", jindy se podob\u00e1 b\u011b\u017en\u00e9 matici. Tyto formy lze vid\u011bt p\u0159i r\u016fzn\u00fdch teplot\u00e1ch a vlhkostech, ale d\u016fvod vzniku t\u00e9 \u010di on\u00e9 formy z\u016fst\u00e1val z\u00e1hadou. L\u00e9ta pozorov\u00e1n\u00ed Libbrechtu pomohla l\u00e9pe pochopit proces krystalizace sn\u011bhov\u00fdch vlo\u010dek.<\/p>\n

V\u00fdzkumy Libbrechtu v t\u00e9to oblasti pomohly vytvo\u0159it nov\u00fd model, kter\u00fd vysv\u011btluje, pro\u010d sn\u011bhov\u00e9 vlo\u010dky a dal\u0161\u00ed sn\u011bhov\u00e9 krystaly vytv\u00e1\u0159ej\u00ed to, co jsme zvykl\u00ed v\u00eddat. Podle jeho teorie, publikovan\u00e9 <\/a><\/noindex>na internetu v \u0159\u00edjnu 2019, popisuje pohyb molekul vody bl\u00edzko bodu zamrz\u00e1n\u00ed (krystalizace) a to, jak konkr\u00e9tn\u00ed pohyby t\u011bchto molekul mohou vyvol\u00e1vat soubor krystal\u016f, kter\u00e9 se vytv\u00e1\u0159ej\u00ed za r\u016fzn\u00fdch podm\u00ednek. Ve sv\u00e9 monografii <\/a><\/noindex>o objemu 540 stran Libbrecht popisuje v\u0161echny znalosti o sn\u011bhov\u00fdch krystalech.<\/p>\n

\u0160estic\u00edp\u00e9 hv\u011bzdy<\/h2>\n

\nUr\u010dit\u011b v\u00edte, \u017ee nen\u00ed mo\u017en\u00e9 vid\u011bt dv\u011b identick\u00e9 sn\u011bhov\u00e9 vlo\u010dky (pokud nebereme v \u00favahu f\u00e1zi jejich vzniku). Tento fakt souvis\u00ed s t\u00edm, jak se krystaly formuj\u00ed na obloze. Sn\u00edh je shrom\u00e1\u017ed\u011bn\u00ed ledov\u00fdch krystal\u016f, kter\u00e9 se vytvo\u0159\u00ed v atmosf\u00e9\u0159e a udr\u017euj\u00ed si sv\u016fj tvar, kdy\u017e padaj\u00ed na Zemi. Vytv\u00e1\u0159ej\u00ed se, kdy\u017e je atmosf\u00e9ra dostate\u010dn\u011b chladn\u00e1, aby nedo\u0161lo ke slou\u010den\u00ed nebo t\u00e1n\u00ed a p\u0159em\u011bn\u011b na mokr\u00fd sn\u00edh nebo d\u00e9\u0161\u0165.<\/p>\n

I kdy\u017e v r\u00e1mci jednoho mraku lze zaznamenat mnoho teplot a \u00farovn\u00ed vlhkosti, pro jednu sn\u011bhovou vlo\u010dku budou tyto prom\u011bnn\u00e9 konstantn\u00ed. Proto sn\u011bhov\u00e1 vlo\u010dka \u010dasto roste symetricky. Na druh\u00e9 stran\u011b je ka\u017ed\u00e1 sn\u011bhov\u00e1 vlo\u010dka vystavena vlivu v\u011btru, slune\u010dn\u00edmu sv\u011btlu a dal\u0161\u00edm faktor\u016fm. V podstat\u011b ka\u017ed\u00fd krystal podl\u00e9h\u00e1 chaosu mraku, a proto nab\u00fdv\u00e1 r\u016fzn\u00fdch tvar\u016f.<\/p>\n

Podle studie Libbrechtova jsou nejran\u011bj\u0161\u00ed \u00favahy o t\u011bchto delik\u00e1tn\u00edch form\u00e1ch zaznamen\u00e1ny v roce 135 p\u0159. n. l. v \u010c\u00edn\u011b. \u201eKv\u011bty rostlin a strom\u016f jsou obvykle p\u011bti\u010detn\u00e9, ale kv\u011bty sn\u011bhu jsou v\u017edy \u0161esti\u010detn\u00e9,\u201c psal v\u011bdec Han Yin. A prvn\u00edm v\u011bdcem, kter\u00fd se pokusil rozlu\u0161tit, pro\u010d tomu tak je, byl pravd\u011bpodobn\u011b Johannes Kepler, n\u011bmeck\u00fd v\u011bdec a erudita.<\/p>\n

V roce 1611 daroval Kepler novoro\u010dn\u00ed d\u00e1rek sv\u00e9mu patronovi, c\u00edsa\u0159i Svat\u00e9 \u0159\u00ed\u0161e \u0159\u00edmsk\u00e9 Rudolfu II.: mal\u00fd trak\u00e1t <\/a><\/noindex>s n\u00e1zvem \u201eO \u0161esti\u00faheln\u00edkov\u00fdch sn\u011bhov\u00fdch vlo\u010dk\u00e1ch\u201c. <\/p>\n

\u201eP\u0159ech\u00e1z\u00edm most, su\u017eov\u00e1n hanbou \u2013 nechal jsem t\u011b bez novoro\u010dn\u00edho d\u00e1rku! A tu se mi nask\u00fdt\u00e1 pohodln\u00e1 p\u0159\u00edle\u017eitost! Vodn\u00ed p\u00e1ry, zhu\u0161\u0165uj\u00edc\u00ed se od chladu na sn\u00edh, padaj\u00ed jako vlo\u010dky na m\u00e9 oble\u010den\u00ed, v\u0161echny jako jedna, \u0161esti\u00faheln\u00edkov\u00e9, s na\u010dechran\u00fdmi paprsky. P\u0159\u00edsah\u00e1m H\u00e9raklovi, tady je n\u011bco, co je men\u0161\u00ed ne\u017e jak\u00e1koliv kapka, m\u00e1 tvar a m\u016f\u017ee slou\u017eit jako dlouho o\u010dek\u00e1van\u00fd novoro\u010dn\u00ed d\u00e1rek pro milovn\u00edka Ni\u010deho a zasluhuje matematiky, kter\u00fd m\u00e1 Nic a dost\u00e1v\u00e1 Nic, nebo\u0165 pad\u00e1 z nebe a skr\u00fdv\u00e1 v sob\u011b podobu \u0161esti\u00faheln\u00e9 hv\u011bzdy!\u201c<\/p><\/blockquote>\n

\u201eMus\u00ed existovat d\u016fvod, pro\u010d m\u00e1 sn\u00edh tvar \u0161esti\u00faheln\u00e9 hv\u011bzdi\u010dky. To nem\u016f\u017ee b\u00fdt n\u00e1hoda,\u201c byl si jist\u00fd Johannes Kepler. Mo\u017en\u00e1 si vybavil dopis od sv\u00e9ho sou\u010dasn\u00edka Thomase Harriotta, anglick\u00e9ho v\u011bdce a astronoma, kter\u00fd tak\u00e9 stihl pracovat jako navig\u00e1tor pro badatele Sira Waltera Raleigha. Kolem roku 1584 Harriott hledal nejefektivn\u011bj\u0161\u00ed zp\u016fsob, jak usklad\u0148ovat d\u011blov\u00e9 koule na palub\u011b Raleighov\u00fdch lod\u00ed. Harriott zjistil, \u017ee hexagon\u00e1ln\u00ed vzory se zdaj\u00ed b\u00fdt nejlep\u0161\u00edm zp\u016fsobem uspo\u0159\u00e1d\u00e1n\u00ed sf\u00e9r, a tuto ot\u00e1zku prob\u00edral v korespondenci s Keplerem. Kepler se ptal, zda se n\u011bco podobn\u00e9ho d\u011bje ve sn\u011bhov\u00fdch vlo\u010dk\u00e1ch a jak\u00fd prvek zp\u016fsobuje a udr\u017euje t\u011bchto \u0161est paprsk\u016f. <\/p>\n

Tvary sn\u011bhov\u00fdch vlo\u010dek<\/b>\"Velk\u00e1
\n
\n\"Velk\u00e1
\n
\n\"Velk\u00e1
\n
\nLze \u0159\u00edci, \u017ee to bylo po\u010d\u00e1te\u010dn\u00ed porozum\u011bn\u00ed princip\u016fm atomov\u00e9 fyziky, o kter\u00fdch se za\u010dne mluvit a\u017e o 300 let pozd\u011bji. Opravu, molekuly vody se sv\u00fdmi dv\u011bma atomy vod\u00edku a jedn\u00edm atomem kysl\u00edku maj\u00ed tendenci se spojovat dohromady a vytv\u00e1\u0159et hexagon\u00e1ln\u00ed struktury. Kepler a jeho sou\u010dasn\u00edci si ani nedok\u00e1zali p\u0159edstavit, jak d\u016fle\u017eit\u00e9 to je.<\/p>\n

Jak \u0159\u00edkaj\u00ed fyzici, d\u00edky vod\u00edkov\u00fdm vazb\u00e1m a interakc\u00edm mezi molekulami m\u016f\u017eeme pozorovat otev\u0159enou krystalickou strukturu. Krom\u011b schopnosti vytv\u00e1\u0159et sn\u011bhov\u00e9 vlo\u010dky hexagon\u00e1ln\u00ed struktura umo\u017e\u0148uje, aby byl led m\u00e9n\u011b hust\u00fd ne\u017e voda, co\u017e m\u00e1 obrovsk\u00fd vliv na geochemii, geofyziku a klima. Jin\u00fdmi slovy, kdyby led neplaval, \u017eivot na Zemi by byl nemo\u017en\u00fd.<\/p>\n

Ale po Keplerov\u011b trakt\u00e1tu bylo pozorov\u00e1n\u00ed sn\u011bhov\u00fdch vlo\u010dek sp\u00ed\u0161e kon\u00ed\u010dkem ne\u017e v\u00e1\u017enou v\u011bdou. V 80. letech 19. stolet\u00ed americk\u00fd fotograf jm\u00e9nem Wilson Bentley, kter\u00fd \u017eil v mal\u00e9m m\u011bst\u011b Jericho (st\u00e1t Vermont, USA) pokryt\u00e9m sn\u011bhem, za\u010dal fotografovat sn\u011bhov\u00e9 vlo\u010dky pomoc\u00ed fotografick\u00fdch desek. Stihl vytvo\u0159it v\u00edce ne\u017e 5000 fotografi\u00ed, ne\u017e zem\u0159el na z\u00e1pal plic.<\/p>\n

\"Velk\u00e1
\n
\nJe\u0161t\u011b pozd\u011bji, ve 30. letech 20. stolet\u00ed, japonsk\u00fd v\u011bdec Ukichiro Nakaya za\u010dal systematick\u00e9 zkoum\u00e1n\u00ed r\u016fzn\u00fdch typ\u016f sn\u011bhov\u00fdch krystal\u016f. V polovin\u011b stolet\u00ed Nakaya p\u011bstoval sn\u011bhov\u00e9 vlo\u010dky v laborato\u0159i s vyu\u017eit\u00edm jednotliv\u00fdch chlup\u016f kr\u00e1l\u00edka um\u00edst\u011bn\u00fdch do ochlazen\u00e9ho prostoru. Hr\u00e1val si s nastaven\u00edm vlhkosti a teploty, p\u011bstoval hlavn\u00ed typy krystal\u016f a sestavil sv\u016fj origin\u00e1ln\u00ed katalog mo\u017en\u00fdch tvar\u016f. Nakaya zjistil, \u017ee hv\u011bzdn\u00e9 sn\u011bhov\u00e9 vlo\u010dky se tvo\u0159\u00ed p\u0159i -2 \u00b0C a -15 \u00b0C. Sloupce se tvo\u0159\u00ed p\u0159i -5 \u00b0C a p\u0159ibli\u017en\u011b p\u0159i -30 \u00b0C. <\/p>\n

Je d\u016fle\u017eit\u00e9 zm\u00ednit, \u017ee p\u0159i teplot\u011b kolem -2 \u00b0C se objevuj\u00ed tenk\u00e9 pl\u00e1tkovit\u00e9 formy sn\u011bhov\u00fdch vlo\u010dek, p\u0159i -5 \u00b0C vytv\u00e1\u0159ej\u00ed tenk\u00e9 sloupce a jehlice, kdy\u017e teplota klesne na -15 \u00b0C, st\u00e1vaj\u00ed se opravdu tenk\u00fdmi pl\u00e1ty, a p\u0159i teplot\u011b pod -30 \u00b0C se vracej\u00ed k tlust\u0161\u00edm sloup\u016fm.<\/p>\n

\"Velk\u00e1
\n
\nZa podm\u00ednek n\u00edzk\u00e9 vlhkosti hv\u011bzdn\u00e9 sn\u011bhov\u00e9 vlo\u010dky vytv\u00e1\u0159ej\u00ed n\u011bkolik v\u011btv\u00ed a p\u0159ipom\u00ednaj\u00ed hexagon\u00e1ln\u00ed pl\u00e1ty, ale p\u0159i vysok\u00e9 vlhkosti se st\u00e1vaj\u00ed slo\u017eit\u011bj\u0161\u00edmi, krajkov\u00fdmi.<\/p>\n

Podle Libbrechtov\u00fdch n\u00e1zor\u016f se d\u016fvody vzniku r\u016fzn\u00fdch forem sn\u011bhov\u00fdch vlo\u010dek staly jasn\u011bj\u0161\u00edmi d\u00edky pr\u00e1ci Nakayi. Bylo zji\u0161t\u011bno, \u017ee sn\u011bhov\u00e9 krystaly se prom\u011b\u0148uj\u00ed v ploch\u00e9 hv\u011bzdy a pl\u00e1ty (a nikoli v trojrozm\u011brn\u00e9 struktury), kdy\u017e okraje rychle rostou ven, zat\u00edmco st\u011bny rostou pomalu nahoru. Tenk\u00e9 sloupy rostou jinak, s rychle rostouc\u00edmi st\u011bnami a pomaleji rostouc\u00edmi okraji.<\/p>\n

Sou\u010dasn\u011b z\u016fstaly hlavn\u00ed procesy ovliv\u0148uj\u00edc\u00ed to, zda se sn\u011bhov\u00e1 vlo\u010dka stane hv\u011bzdou nebo sloupem, nejasn\u00e9. Mo\u017en\u00e1 je tajemstv\u00ed skryto v teplotn\u00edch podm\u00ednk\u00e1ch. A Libbrecht se sna\u017eil naj\u00edt odpov\u011b\u010f na tuto ot\u00e1zku.<\/p>\n

Recept na sn\u011bhovou vlo\u010dku<\/h2>\n

\nSpolu se sv\u00fdm mal\u00fdm t\u00fdmem v\u00fdzkumn\u00edk\u016f se Libbrecht sna\u017eil vymyslet recept na sn\u011bhovou vlo\u010dku. To znamen\u00e1 ur\u010dit\u00fd soubor rovnic a parametr\u016f, kter\u00e9 lze nahr\u00e1t do po\u010d\u00edta\u010de a z\u00edskat od AI n\u00e1dhern\u00e9 rozmanit\u00e9 sn\u011bhov\u00e9 vlo\u010dky.<\/p>\n

Sv\u00e1 v\u00fdzkumy Kenneth Libbrecht zah\u00e1jil p\u0159ed dvaceti lety pot\u00e9, co se dozv\u011bd\u011bl o exotick\u00e9 form\u011b sn\u011bhov\u00e9 vlo\u010dky, naz\u00fdvan\u00e9 uzav\u0159en\u00fd sloup. Ta vypad\u00e1 jako c\u00edvka na nit nebo dv\u011b kola a osa. Naroden\u00fd na severu zem\u011b byl \u0161okov\u00e1n t\u00edm, \u017ee nikdy nevid\u011bl takovou sn\u011bhovou vlo\u010dku.<\/p>\n

Ohromen nekone\u010dn\u00fdmi formami sn\u011bhov\u00fdch krystal\u016f, zab\u00fdval se studov\u00e1n\u00edm<\/a><\/noindex> jejich p\u0159\u00edrody, vytvo\u0159il laborato\u0159 pro p\u011bstov\u00e1n\u00ed sn\u011bhov\u00fdch vlo\u010dek. V\u00fdsledky dlouholet\u00fdch pozorov\u00e1n\u00ed pomohly vytvo\u0159it model, kter\u00fd s\u00e1m autor pova\u017euje za pr\u016flomov\u00fd. Navrhl my\u0161lenku molekul\u00e1rn\u00ed difuze na z\u00e1klad\u011b povrchov\u00e9 energie. Tato my\u0161lenka popisuje, jak r\u016fst sn\u011bhov\u00e9ho krystalu z\u00e1vis\u00ed na po\u010d\u00e1te\u010dn\u00edch podm\u00ednk\u00e1ch a chov\u00e1n\u00ed molekul, kter\u00e9 ho tvo\u0159\u00ed.<\/p>\n

\"Velk\u00e1
\n
\nP\u0159edstavte si, \u017ee molekuly vody jsou svobodn\u011b um\u00edst\u011bny, kdy\u017e se p\u00e1ry vody teprve za\u010d\u00ednaj\u00ed zamrzat. Kdyby bylo mo\u017en\u00e9 b\u00fdt uvnit\u0159 mali\u010dk\u00e9 observato\u0159e a pozorovat tento proces, mohli byste vid\u011bt, jak molekuly zmrzl\u00e9 vody za\u010d\u00ednaj\u00ed tvo\u0159it tuh\u00fd m\u0159\u00ed\u017ekov\u00fd syst\u00e9m, kde je ka\u017ed\u00fd atom kysl\u00edku obklopen \u010dty\u0159mi atomy vod\u00edku. Tyto krystaly rostou t\u00edm, \u017ee do jejich struktury za\u010dle\u0148uj\u00ed molekuly vody z okoln\u00edho vzduchu. Mohou r\u016fst ve dvou z\u00e1kladn\u00edch sm\u011brech: nahoru nebo ven.<\/p>\n

Tenk\u00fd ploch\u00fd krystal (ploch\u00fd nebo hv\u011bzdicov\u00fd) se vytv\u00e1\u0159\u00ed, kdy\u017e se okraje formuj\u00ed rychleji ne\u017e dv\u011b plochy krystalu. R\u016fst krystalu se bude \u0161\u00ed\u0159it ven. Nicm\u00e9n\u011b, kdy\u017e jeho plochy rostou rychleji ne\u017e jeho okraje, krystal se st\u00e1v\u00e1 vy\u0161\u0161\u00edm a vytv\u00e1\u0159\u00ed jehlu, dut\u00fd sloup nebo ty\u010d.<\/p>\n

Vz\u00e1cn\u00e9 formy sn\u011bhov\u00fdch vlo\u010dek<\/b>\"Velk\u00e1
\n
\n\"Velk\u00e1
\n
\n\"Velk\u00e1
\n
\nJe\u0161t\u011b jedna v\u011bc. V\u0161imn\u011bte si t\u0159et\u00ed fotografie po\u0159\u00edzen\u00e9 Libbrechtom v severn\u00edm Ontariu. To je krystal se \u201euzav\u0159en\u00fdmi sloupci\u201c \u2014 dv\u011b desky p\u0159ipevn\u011bn\u00e9 k konc\u016fm tlust\u00e9ho sloupcov\u00e9ho krystalu. V tomto p\u0159\u00edpad\u011b je ka\u017ed\u00e1 deska rozd\u011blena na p\u00e1r mnohem ten\u010d\u00edch desek. Pod\u00edvejte se na okraje, uvid\u00edte, jak se deska d\u011bl\u00ed na dv\u011b. Celkov\u00e1 d\u00e9lka ledov\u00e9ho sloupce je p\u0159ibli\u017en\u011b 1,5 mm.<\/p>\n

Podle modelu Libbrechta se vodn\u00ed p\u00e1ra nejprve usazuje na roz\u00edch krystalu a pot\u00e9 se \u0161\u00ed\u0159\u00ed (difunduje) po povrchu bu\u010f k okraj\u016fm krystalu, nebo k jeho hran\u00e1m, co\u017e zp\u016fsobuje, \u017ee krystal roste ven nebo nahoru. Kter\u00fd z t\u011bchto proces\u016f \u201evyhraje\u201c, z\u00e1vis\u00ed p\u0159edev\u0161\u00edm na teplot\u011b.<\/p>\n

Je t\u0159eba poznamenat, \u017ee model je \u201epoluempirick\u00fd\u201c. To znamen\u00e1, \u017ee je \u010d\u00e1ste\u010dn\u011b vytvo\u0159en tak, aby vyhovoval d\u011bn\u00ed, a ne aby vysv\u011btloval principy r\u016fstu sn\u011bhov\u00fdch vlo\u010dek. Nestability a interakce mezi bezpo\u010dtem molekul jsou p\u0159\u00edli\u0161 slo\u017eit\u00e9 na to, aby byly zcela odhaleny. P\u0159esto z\u016fst\u00e1v\u00e1 nad\u011bje, \u017ee my\u0161lenky Libbrechta poslou\u017e\u00ed jako z\u00e1klad pro komplexn\u00ed model dynamiky r\u016fstu ledu, kter\u00fd bude mo\u017en\u00e9 podrobn\u011bji rozpracovat pomoc\u00ed podrobn\u011bj\u0161\u00edch m\u011b\u0159en\u00ed a experiment\u016f.<\/p>\n

Ned\u011blejte si dojem, \u017ee tyto pozorov\u00e1n\u00ed zaj\u00edmaj\u00ed \u00fazk\u00fd okruh v\u011bdc\u016f. Podobn\u00e9 ot\u00e1zky se objevuj\u00ed v oblasti fyziky kondenzovan\u00fdch l\u00e1tek a v dal\u0161\u00edch oblastech. Molekuly l\u00e9k\u016f, polovodi\u010dov\u00e9 \u010dipy pro po\u010d\u00edta\u010de, slune\u010dn\u00ed \u010dl\u00e1nky a mnoh\u00e9 dal\u0161\u00ed obory se spol\u00e9haj\u00ed na vysoce kvalitn\u00ed krystaly, a cel\u00e9 t\u00fdmy se zab\u00fdvaj\u00ed jejich p\u011bstov\u00e1n\u00edm. Tak\u017ee Libbrechtovi milovan\u00e9 sn\u011bhov\u00e9 vlo\u010dky mohou zcela ur\u010dit\u011b slou\u017eit v\u011bd\u011b.<\/p>\n

Co dal\u0161\u00edho si m\u016f\u017eete p\u0159e\u010d\u00edst v blogu Cloud4Y<\/a><\/noindex><\/b><\/p>\n

\u2192 Slan\u00e1 slune\u010dn\u00ed energie<\/a><\/noindex>
\n\u2192 Pentesteri na p\u0159edn\u00ed linii kybernetick\u00e9 bezpe\u010dnosti<\/a><\/noindex>
\n\u2192 Startupy, kter\u00e9 dok\u00e1\u017e\u00ed p\u0159ekvapit<\/a><\/noindex>
\n\u2192 Internet na vzducholod\u00edch<\/a><\/noindex>
\n\u2192 Jsou v datov\u00fdch centrech pot\u0159ebn\u00e9 podlo\u017eky?<\/a><\/noindex><\/p>\n

Sledujte n\u00e1\u0161 Telegram<\/a><\/noindex>-kan\u00e1l, abyste nezme\u0161kali dal\u0161\u00ed \u010dl\u00e1nek! P\u00ed\u0161eme maxim\u00e1ln\u011b dvakr\u00e1t t\u00fddn\u011b a pouze relevantn\u011b. Mimochodem, pokud se je\u0161t\u011b nev\u00edte, startupy mohou z\u00edskat 10 000 $ od Cloud4Y. Podm\u00ednky a dotazn\u00edk pro z\u00e1jemce \u2014 na na\u0161ich webov\u00fdch str\u00e1nk\u00e1ch: bit.ly\/2sj6dPK<\/a><\/noindex>
\n
Zdroj: habr.com<\/a><\/p>","protected":false,"gt_translate_keys":[{"key":"rendered","format":"html"}]},"excerpt":{"rendered":"

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\u043c\u0435\u0448\u0430\u044e\u0442 \u043e\u0449\u0443\u0442\u0438\u0442\u044c \u0440\u0430\u0434\u043e\u0441\u0442\u044c \u043e\u0442 \u043f\u0440\u0438\u0432\u044b\u0447\u043d\u044b\u0445 \u0437\u0438\u043c\u043d\u0438\u0445 \u0437\u0430\u0431\u0430\u0432. \u041f\u043e\u044d\u0442\u043e\u043c\u0443 Cloud4Y \u043f\u0440\u0435\u0434\u043b\u0430\u0433\u0430\u0435\u0442 \u0434\u043e\u0431\u0430\u0432\u0438\u0442\u044c \u043d\u0435\u043c\u043d\u043e\u0433\u043e \u0441\u043d\u0435\u0433\u0430 \u0432 \u043d\u0430\u0448\u0443 \u0436\u0438\u0437\u043d\u044c, \u043f\u043e\u0433\u043e\u0432\u043e\u0440\u0438\u0432 \u043e\u2026 \u0441\u043d\u0435\u0436\u0438\u043d\u043a\u0430\u0445. \u0421\u0447\u0438\u0442\u0430\u0435\u0442\u0441\u044f, \u0447\u0442\u043e \u0441\u043d\u0435\u0436\u0438\u043d\u043a\u0438 \u0431\u044b\u0432\u0430\u044e\u0442 \u0442\u043e\u043b\u044c\u043a\u043e \u0434\u0432\u0443\u0445 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