{"id":32231,"date":"2013-03-19T18:56:16","date_gmt":"2013-03-19T15:56:16","guid":{"rendered":"http:\/\/www.fyysika.ee\/uudised\/?p=32231"},"modified":"2013-03-24T01:02:34","modified_gmt":"2013-03-23T22:02:34","slug":"esimene-grafeenist-kolar-seljatab-konkurentsi","status":"publish","type":"post","link":"https:\/\/www.fyysika.ee\/?p=32231","title":{"rendered":"Esimene grafeenk\u00f5lar seljatab konkurentsi"},"content":{"rendered":"

Insenerid esitlesid 13. m\u00e4rtsil inimkonna esimest elektrostaatilist grafeenk\u00f5larit, mille heliomadused on v\u00e4hemalt sama head kui parematel poem\u00fc\u00fcgi k\u00f5rvaklappidel.<\/strong><\/p>\n

Enamus valjuh\u00e4\u00e4ldeid tekitavad heli diafragmap\u00f5him\u00f5ttel. Heli elektrisignaal juhitakse membraani elektroodidele, mis p\u00f5hjustab membraani v\u00f5nkumise ning seega helilaineid. \u201eInimese kuulmisl\u00e4ve 20 Hz \u2013 20kHz sagedusvahemiku ideaalne k\u00f5lar on pideva helir\u00f5huprofiiliga. Iga sagedusega elektrisisendile peab vastama pideva amplituudjaotusega v\u00e4ljund,\u201c selgitasid California Berkeley teadlased Qin Zhou ning Alex Zettl.
\n\"\"<\/a>
\n<\/strong><\/p>\n

Varemalt on grafeenile lavavalgust helgitud eelk\u00f5ige heade elektriliste omaduste t\u00f5ttu. N\u00fc\u00fcd on j\u00e4rg imematerjali mehaanika k\u00e4es.<\/p>\n

K\u00f5lari kvaliteedi p\u00f5hjused on h\u00f5lpsasti selgitatavad. Iga k\u00f5lari diafragma on olemuselt lihtne harmooniline ostsillaator. Sellel on v\u00e4ike mass ning vaikiolekut taastav j\u00f5umoment, mis m\u00e4\u00e4rab sisendsageduste kostekarakteristikud. Enamik diafragmasid vajab laiema helispektri saavutamiseks summutamist. Ent summutamismeetodid muutuvad iga sagedusvahemiku lisandumisega eksponentsiaalselt keerulisemaks ja kallimaks. Keerulise summutusega k\u00f5lar tarbib enamasti rohkem energiat.<\/p>\n

Lihtsaim summutusmeetod on v\u00e4ga \u00f5hukese ning v\u00e4ikse j\u00e4ikusteguriga diafragma kasutamine. Et keskmine materjal muutub \u00f5henedes ka hapramaks, on paremate diafragmak\u00f5larite valmistamine olnud kammitsetud.<\/p>\n

Grafeen on otse ideaalne diafragmamaterjal. \u201eSee juhib elektrit, on tugev ning samas v\u00e4ga kerge. Mitmekihilise grafeeni j\u00e4ikustegurit on kerge muuta,\u201c \u00fctles Zhou.<\/p>\n

Zhou ja Zettl-i grafeendiafragma on 30 nm paksune ning 5 mm l\u00e4bim\u00f5\u00f5duga. Selle heliv\u00e4ljund normeeriti Sennheiser MX-400 klappidel. Tulemused olid paljulubavad. \u201eIsegi optimisatsioonita on grafeenk\u00f5lar suuteline tootma suurep\u00e4rase sageduskostega heli, mis on v\u00f5rreldav parimategi elektrostaatiliste k\u00f5rvaklappidega,\u201c lisas Zettl.<\/p>\n

\u00d5hk-summutatud grafeenmembraan muundab enamuse deformatsioonienergiast heliks ja on seet\u00f5ttu energias\u00e4\u00e4stlik. Mobiilseadmete puhul on energias\u00e4\u00e4stlikkus \u00fclioluline.<\/p>\n

Allikas: Technologyreview<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

Insenerid esitlesid 13. m\u00e4rtsil inimkonna esimest elektrostaatilist grafeenk\u00f5larit, mille heliomadused on v\u00e4hemalt sama head kui parematel poem\u00fc\u00fcgi k\u00f5rvaklappidel. Enamus valjuh\u00e4\u00e4ldeid tekitavad heli diafragmap\u00f5him\u00f5ttel. Heli elektrisignaal juhitakse membraani elektroodidele, mis p\u00f5hjustab membraani v\u00f5nkumise ning seega helilaineid. \u201eInimese kuulmisl\u00e4ve 20 Hz \u2013 20kHz sagedusvahemiku ideaalne k\u00f5lar on pideva helir\u00f5huprofiiliga. Iga sagedusega elektrisisendile peab vastama pideva amplituudjaotusega v\u00e4ljund,\u201c […]<\/p>\n","protected":false},"author":449,"featured_media":32232,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_genesis_hide_title":false,"_genesis_hide_breadcrumbs":false,"_genesis_hide_singular_image":false,"_genesis_hide_footer_widgets":false,"_genesis_custom_body_class":"","_genesis_custom_post_class":"","_genesis_layout":"","footnotes":""},"categories":[16],"tags":[45],"class_list":{"0":"post-32231","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-teadusuudis","8":"tag-grafeengrafaan","9":"entry"},"_links":{"self":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/posts\/32231","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/users\/449"}],"replies":[{"embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=32231"}],"version-history":[{"count":0,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/posts\/32231\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/media\/32232"}],"wp:attachment":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=32231"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=32231"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=32231"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}