{"id":56841,"date":"2023-04-25T16:48:22","date_gmt":"2023-04-25T21:48:22","guid":{"rendered":"https:\/\/www.bjultrasonic.com\/what-blocks-ultrasonic-sound-waves\/"},"modified":"2025-01-27T06:15:58","modified_gmt":"2025-01-27T11:15:58","slug":"what-blocks-ultrasonic-sound-waves","status":"publish","type":"post","link":"https:\/\/www.bjultrasonic.com\/cs\/what-blocks-ultrasonic-sound-waves\/","title":{"rendered":"Ultrazvuk: Co Brzd\u00ed Jeho \u0160\u00ed\u0159en\u00ed?"},"content":{"rendered":"<p>Ultrazvukov\u00e9 vlny, neviditeln\u00e9 nosi\u010de energie, nach\u00e1zej\u00ed uplatn\u011bn\u00ed v mnoha oblastech lidsk\u00e9ho \u017eivota, od l\u00e9ka\u0159stv\u00ed a\u017e po pr\u016fmysl.  Pochopen\u00ed toho, co tyto vlny blokuje, je kl\u00ed\u010dov\u00e9 pro jejich efektivn\u00ed vyu\u017eit\u00ed a tak\u00e9 pro minimalizaci ne\u017e\u00e1douc\u00edch interferenc\u00ed.  Tento \u010dl\u00e1nek se detailn\u011bji zam\u011b\u0159\u00ed na materi\u00e1ly a faktory, kter\u00e9 ovliv\u0148uj\u00ed \u0161\u00ed\u0159en\u00ed ultrazvuku.<\/p>\n<h3>Materi\u00e1ly s vysokou hustotou<\/h3>\n<p>Hustota materi\u00e1lu hraje kl\u00ed\u010dovou roli v absorpci a odrazu ultrazvukov\u00fdch vln.  Materi\u00e1ly s vysokou hustotou, jako je ocel, olovo nebo beton, efektivn\u011b odr\u00e1\u017eej\u00ed ultrazvukov\u00e9 vlny.  \u010c\u00edm v\u011bt\u0161\u00ed je rozd\u00edl v akustick\u00e9 impedanci mezi prost\u0159ed\u00edm, ve kter\u00e9m se vlny \u0161\u00ed\u0159\u00ed, a materi\u00e1lem, na kter\u00fd dopadaj\u00ed, t\u00edm v\u011bt\u0161\u00ed je odraz.  Naproti tomu materi\u00e1ly s n\u00edzkou hustotou, nap\u0159\u00edklad d\u0159evo nebo p\u011bna, absorbuj\u00ed a rozptyluj\u00ed ultrazvukov\u00e9 vlny do v\u011bt\u0161\u00ed m\u00edry.<\/p>\n<table class=\"table table-striped table-bordered\">\n<thead>\n<tr>\n<th>Materi\u00e1l<\/th>\n<th>Hustota (kg\/m\u00b3)<\/th>\n<th>Akustick\u00e1 impedance (MRayls)<\/th>\n<th>Odrazivost (%) (na rozhran\u00ed vzduch-materi\u00e1l)<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Vzduch<\/td>\n<td>1.2<\/td>\n<td>0.00042<\/td>\n<td>&#8211;<\/td>\n<\/tr>\n<tr>\n<td>D\u0159evo (borovice)<\/td>\n<td>500<\/td>\n<td>2.6<\/td>\n<td>99.9 %<\/td>\n<\/tr>\n<tr>\n<td>Ocel<\/td>\n<td>7850<\/td>\n<td>46.6<\/td>\n<td>99.99%<\/td>\n<\/tr>\n<tr>\n<td>Voda<\/td>\n<td>1000<\/td>\n<td>1.48<\/td>\n<td>99.7%<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h3>Vliv tlou\u0161\u0165ky materi\u00e1lu<\/h3>\n<p>Tlou\u0161\u0165ka materi\u00e1lu rovn\u011b\u017e ovliv\u0148uje jeho schopnost blokovat ultrazvuk. Tenk\u00fd materi\u00e1l m\u016f\u017ee ultrazvuk propustit, zat\u00edmco tlust\u00fd materi\u00e1l jej efektivn\u011b absorbuje nebo odraz\u00ed.  Tento efekt je z\u00e1visl\u00fd na frekvenci ultrazvuku &#8211; vy\u0161\u0161\u00ed frekvence jsou v\u00edce absorbov\u00e1ny ten\u010d\u00edmi vrstvami materi\u00e1lu.<\/p>\n<h3>Vliv frekvence ultrazvuku<\/h3>\n<p>Frekvence ultrazvukov\u00fdch vln je dal\u0161\u00edm d\u016fle\u017eit\u00fdm faktorem. Vy\u0161\u0161\u00ed frekvence se sn\u00e1ze absorbuj\u00ed v r\u016fzn\u00fdch materi\u00e1lech, zat\u00edmco ni\u017e\u0161\u00ed frekvence pronikaj\u00ed hloub\u011bji.  Nap\u0159\u00edklad ultrazvukov\u00e9 \u010didlo pracuj\u00edc\u00ed na frekvenci 20 kHz bude m\u00edt jinou penetraci do materi\u00e1lu ne\u017e \u010didlo pracuj\u00edc\u00ed na 1 MHz.  Tento aspekt je d\u016fle\u017eit\u00fd p\u0159i v\u00fdb\u011bru vhodn\u00e9ho senzoru pro danou aplikaci.<\/p>\n<h3>Vlnov\u00e1 d\u00e9lka a rozptyl<\/h3>\n<p>Vlnov\u00e1 d\u00e9lka ultrazvuku je \u00fazce spjata s jeho frekvenc\u00ed. Krat\u0161\u00ed vlnov\u00e9 d\u00e9lky se sn\u00e1ze rozptyluj\u00ed na nerovnostech povrchu materi\u00e1lu.  To m\u016f\u017ee v\u00e9st k oslaben\u00ed sign\u00e1lu a sn\u00ed\u017een\u00ed \u00fa\u010dinnosti ultrazvukov\u00e9ho m\u011b\u0159en\u00ed.<\/p>\n<h3>Absorpce v materi\u00e1lu<\/h3>\n<p>Mnoho materi\u00e1l\u016f absorbuje energii ultrazvukov\u00fdch vln, \u010d\u00edm\u017e se sni\u017euje jejich intenzita.  Tato absorpce je z\u00e1visl\u00e1 na vlastnostech materi\u00e1lu a frekvenci ultrazvuku.  V n\u011bkter\u00fdch p\u0159\u00edpadech m\u016f\u017ee b\u00fdt absorpce tak vysok\u00e1, \u017ee ultrazvukov\u00fd sign\u00e1l je prakticky zcela utlumen.<\/p>\n<h3>Vliv teploty a tlaku<\/h3>\n<p>Teplota a tlak prost\u0159ed\u00ed mohou tak\u00e9 ovlivnit \u0161\u00ed\u0159en\u00ed ultrazvuku. Zm\u011bny t\u011bchto parametr\u016f mohou v\u00e9st k zm\u011bn\u00e1m rychlosti \u0161\u00ed\u0159en\u00ed a absorpce ultrazvukov\u00fdch vln v materi\u00e1lu.<\/p>\n<p>Z\u00e1v\u011brem lze \u0159\u00edci, \u017ee blokov\u00e1n\u00ed ultrazvukov\u00fdch vln je komplexn\u00ed jev ovlivn\u011bn\u00fd mnoha faktory, v\u010detn\u011b hustoty, tlou\u0161\u0165ky a typu materi\u00e1lu, frekvence ultrazvuku, vlnov\u00e9 d\u00e9lky, teploty a tlaku.  Pochopen\u00ed t\u011bchto faktor\u016f je nezbytn\u00e9 pro n\u00e1vrh a pou\u017eit\u00ed ultrazvukov\u00fdch syst\u00e9m\u016f v r\u016fzn\u00fdch aplikac\u00edch.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Ultrazvukov\u00e9 vlny, neviditeln\u00e9 nosi\u010de energie, nach\u00e1zej\u00ed uplatn\u011bn\u00ed v mnoha oblastech lidsk\u00e9ho \u017eivota, od l\u00e9ka\u0159stv\u00ed a\u017e po pr\u016fmysl. Pochopen\u00ed toho, co tyto vlny blokuje, je kl\u00ed\u010dov\u00e9 pro jejich efektivn\u00ed vyu\u017eit\u00ed a tak\u00e9 pro minimalizaci ne\u017e\u00e1douc\u00edch interferenc\u00ed. Tento \u010dl\u00e1nek se detailn\u011bji zam\u011b\u0159\u00ed na materi\u00e1ly a faktory, kter\u00e9 ovliv\u0148uj\u00ed \u0161\u00ed\u0159en\u00ed ultrazvuku. Materi\u00e1ly s vysokou hustotou Hustota materi\u00e1lu hraje<\/p>\n","protected":false},"author":1,"featured_media":26471,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6415],"tags":[],"class_list":["post-56841","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog","prodpage-classic"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/posts\/56841","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/comments?post=56841"}],"version-history":[{"count":0,"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/posts\/56841\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/media\/26471"}],"wp:attachment":[{"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/media?parent=56841"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/categories?post=56841"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/tags?post=56841"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}