Imitha ye-ultraviolet

Kwifiziksi, imitha ye-ultraviolet , ehlala ifinyeziwe kwi-UV kwaye eyaziwa ngokuba yimitha ye-UV okanye ukukhanya kwe-UV, ithathwa njengemitha ye -electromagnetic spectrum phakathi kokubonakalayo. ukukhanya kunye ne -4 nm .  Imitha ye-Ultraviolet yenza malunga ne-10% yokukhanya okukhutshwa liLanga kwaye iveliswa ziigesi ze-ionized kunye nezibane ezithile ( izibane zemercury vapor kunye nezibane zeWood ). 

Imitha ye-UV ayibonakali emehlweni abantu, ngokuqhelekileyo ayiboni ukukhanya ngobude obungaphantsi kwama-390. nm. Nangona kunjalo, kukho okungafaniyo: phantsi kweemeko ezithile, abantwana kunye nabaselula banokubona i-ultraviolet ukuya kuma-310. nm.   I -lens, ngokubanzi, ihluza i-UV-B okanye i-frequencies ephezulu, kodwa abantu abaphethwe yi-pathologies efana ne -aphasia (ukungabikho kwe- lens ) banokubona kwakhona kwi-UV band. Imitha yeUV ekufutshane nobude obubonakalayo ebantwini inokubonwa zizinambuzane,  ezinye izilwanyana ezincancisayo kunye neentaka ezininzi. 

Imitha ye-UV inamandla kakhulu, inamandla amakhulu e-ionizing kunye ne-photoelectric, ibangela i-fluorescence kunye ne -phosphorescence kwizinto ezahlukeneyo, kwaye ineziphumo ezibonakalayo zebhayoloji, kuquka nokuguqulwa kwesakhiwo se -DNA .  I-UV kubude bamaza amade (ukusuka ~ 200 ukuya kwi-400 nm) inokubangela ukusabela kweekhemikhali, njengokukhazimla okanye i-fluorescence phenomena.

Iimpembelelo zebhayoloji ze-UV, ngenxa yokusebenzisana kwazo kunye neemolekyuli zezinto eziphilayo, zinoxanduva lweziganeko ezifana nokutshisa, i-freckles kunye nokutshiswa kwelanga; zikwamela oyena nobangela womhlaza wolusu . Nayiphi na into ephilayo inokonakala kanobom yimitha ye-UV evela eLangeni ukuba indawo elungileyo yemitha yemitha ibingahluzwanga yiatmosfera yoMhlaba . Ubude obufutshane be-ultraviolet, obungaphantsi kwe-121 nm, bukhupha umoya ngokukhawuleza kangangokuba uphantse ufunxeke ngokupheleleyo ngaphambi kokuba ufikelele emhlabeni. Ngakolunye uhlangothi, i-ultraviolet nayo inoxanduva lokuqinisa amathambo, ukuthatha inxaxheba ekubunjweni kwe-vitamin D, kwiindawo ezininzi ze-vertebrates zomhlaba , ngoko ke i-UV inemiphumo enenzuzo kunye neyingozi kwimpilo yabantu (kuxhomekeke kakhulu kwi-dose).