{"id":60279,"date":"2023-04-21T22:22:19","date_gmt":"2023-04-22T03:22:19","guid":{"rendered":"https:\/\/www.bjultrasonic.com\/how-to-generate-ultrasound\/"},"modified":"2025-01-27T06:08:31","modified_gmt":"2025-01-27T11:08:31","slug":"how-to-generate-ultrasound","status":"publish","type":"post","link":"https:\/\/www.bjultrasonic.com\/cs\/how-to-generate-ultrasound\/","title":{"rendered":"Generov\u00e1n\u00ed ultrazvuku: Princip a techniky"},"content":{"rendered":"<p>Ultrazvuk je v\u0161udyp\u0159\u00edtomn\u00fd v modern\u00ed medic\u00edn\u011b, pr\u016fmyslu a dal\u0161\u00edch oblastech. Jeho generov\u00e1n\u00ed je fascinuj\u00edc\u00ed proces, kter\u00fd spo\u010d\u00edv\u00e1 v p\u0159em\u011bn\u011b elektrick\u00e9 energie na mechanick\u00e9 vibrace, a n\u00e1sledn\u011b na zvukov\u00e9 vlny o frekvenci vy\u0161\u0161\u00ed ne\u017e 20 kHz, tedy nad hranic\u00ed sly\u0161itelnosti lidsk\u00e9ho ucha.  Tento \u010dl\u00e1nek se podrobn\u011b zam\u011b\u0159\u00ed na principy generov\u00e1n\u00ed ultrazvuku a na r\u016fzn\u00e9 metody, kter\u00e9 se k tomuto \u00fa\u010delu pou\u017e\u00edvaj\u00ed.<\/p>\n<h3>Piezoelektrick\u00fd jev a jeho vyu\u017eit\u00ed v generov\u00e1n\u00ed ultrazvuku<\/h3>\n<p>Nejpou\u017e\u00edvan\u011bj\u0161\u00ed metodou generov\u00e1n\u00ed ultrazvuku je vyu\u017eit\u00ed piezoelektrick\u00e9ho jevu.  Tento jev popisuje schopnost n\u011bkter\u00fdch krystalick\u00fdch materi\u00e1l\u016f, nap\u0159\u00edklad k\u0159emene nebo keramiky (nap\u0159. titan\u00e1t barnat\u00fd), m\u011bnit sv\u00e9 rozm\u011bry v z\u00e1vislosti na aplikovan\u00e9m elektrick\u00e9m poli.  Aplikac\u00ed st\u0159\u00eddav\u00e9ho nap\u011bt\u00ed na piezoelektrick\u00fd prvek se dos\u00e1hne jeho periodick\u00e9 expanze a kontrakce, co\u017e vede k mechanick\u00fdm vibrac\u00edm o frekvenci odpov\u00eddaj\u00edc\u00ed frekvenci st\u0159\u00eddav\u00e9ho nap\u011bt\u00ed. Pokud je tato frekvence nad 20 kHz, generuj\u00ed se ultrazvukov\u00e9 vlny.  Kvalita a intenzita generovan\u00e9ho ultrazvuku z\u00e1vis\u00ed na vlastnostech piezoelektrick\u00e9ho materi\u00e1lu, jeho geometrii a frekvenci aplikovan\u00e9ho nap\u011bt\u00ed.<\/p>\n<table class=\"table table-striped table-bordered\">\n<thead>\n<tr>\n<th>Materi\u00e1l<\/th>\n<th>Piezoelektrick\u00e1 konstanta (pC\/N)<\/th>\n<th>Frekven\u010dn\u00ed rozsah (MHz)<\/th>\n<th>V\u00fdhody<\/th>\n<th>Nev\u00fdhody<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>K\u0159emen<\/td>\n<td>2,3<\/td>\n<td>1-100<\/td>\n<td>Vysok\u00e1 stabilita, odolnost<\/td>\n<td>N\u00edzk\u00e1 piezoelektrick\u00e1 konstanta<\/td>\n<\/tr>\n<tr>\n<td>Titan\u00e1t barnat\u00fd (BaTiO\u2083)<\/td>\n<td>190<\/td>\n<td>1-1000<\/td>\n<td>Vysok\u00e1 piezoelektrick\u00e1 konstanta<\/td>\n<td>Ni\u017e\u0161\u00ed stabilita, citlivost na teplotu<\/td>\n<\/tr>\n<tr>\n<td>PZT (Zirkon\u00e1t titani\u010ditan olovnat\u00fd)<\/td>\n<td>&gt; 500<\/td>\n<td>1-1000<\/td>\n<td>Velmi vysok\u00e1 piezoelektrick\u00e1 konstanta<\/td>\n<td>Toxicita olova<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h3>Magnetostrik\u010dn\u00ed metoda generov\u00e1n\u00ed ultrazvuku<\/h3>\n<p>Dal\u0161\u00ed metodou generov\u00e1n\u00ed ultrazvuku je magnetostrikce. Tento jev popisuje zm\u011bnu rozm\u011br\u016f feromagnetick\u00fdch materi\u00e1l\u016f v z\u00e1vislosti na aplikovan\u00e9m magnetick\u00e9m poli.  Aplikac\u00ed st\u0159\u00eddav\u00e9ho magnetick\u00e9ho pole na magnetostrik\u010dn\u00ed materi\u00e1l se dos\u00e1hne jeho periodick\u00e9 expanze a kontrakce, podobn\u011b jako u piezoelektrick\u00e9ho jevu.  Magnetostrik\u010dn\u00ed metoda se \u010dasto vyu\u017e\u00edv\u00e1 pro generov\u00e1n\u00ed ultrazvuku o ni\u017e\u0161\u00edch frekvenc\u00edch a vy\u0161\u0161\u00edch v\u00fdkonech.  Nicm\u00e9n\u011b, tato metoda je obecn\u011b m\u00e9n\u011b efektivn\u00ed a p\u0159esn\u00e1 ne\u017e piezoelektrick\u00e1 metoda.<\/p>\n<h3>Gener\u00e1tory ultrazvuku: design a parametry<\/h3>\n<p>Gener\u00e1tory ultrazvuku se skl\u00e1daj\u00ed z n\u011bkolika kl\u00ed\u010dov\u00fdch komponent:  gener\u00e1toru vysokofrekven\u010dn\u00edho nap\u011bt\u00ed, piezoelektrick\u00e9ho (nebo magnetostrik\u010dn\u00edho) p\u0159evodn\u00edku a obvykle i akustick\u00e9 \u010do\u010dky pro fokusaci ultrazvuku.  Konstrukce a parametry gener\u00e1toru jsou kritick\u00e9 pro dosa\u017een\u00ed po\u017eadovan\u00fdch charakteristik ultrazvuku, jako je frekvence, intenzita a tvar akustick\u00e9ho svazku.  V\u00fdb\u011br spr\u00e1vn\u00e9ho materi\u00e1lu pro p\u0159evodn\u00edk a jeho geometrie jsou kl\u00ed\u010dov\u00e9 pro optimalizaci v\u00fdkonu. Nap\u0159\u00edklad pro aplikace v medic\u00edn\u011b je d\u016fle\u017eit\u00e1 p\u0159esn\u00e1 kontrola parametr\u016f ultrazvuku, aby se zabr\u00e1nilo po\u0161kozen\u00ed tk\u00e1n\u011b.<\/p>\n<h3>Aplikace ultrazvuku<\/h3>\n<p>Ultrazvuk nach\u00e1z\u00ed \u0161irok\u00e9 uplatn\u011bn\u00ed v r\u016fzn\u00fdch oblastech. V medic\u00edn\u011b se pou\u017e\u00edv\u00e1 k diagnostice (ultrazvukov\u00e9 zobrazov\u00e1n\u00ed) a terapii (ultrazvukov\u00e1 chirurgie, ultrazvukov\u00e1 terapie). V pr\u016fmyslu se vyu\u017e\u00edv\u00e1 k \u010di\u0161t\u011bn\u00ed, sva\u0159ov\u00e1n\u00ed, ultrazvukov\u00e9 defektoskopii a mnoho dal\u0161\u00edch aplikac\u00ed.  Pou\u017eit\u00ed ultrazvuku z\u00e1vis\u00ed na specifick\u00fdch po\u017eadavc\u00edch dan\u00e9 aplikace, a proto se vol\u00ed r\u016fzn\u00e9 frekvence a intenzity ultrazvuku.<\/p>\n<p>Z\u00e1v\u011brem lze \u0159\u00edci, \u017ee generov\u00e1n\u00ed ultrazvuku je zalo\u017eeno na p\u0159em\u011bn\u011b elektrick\u00e9 nebo magnetick\u00e9 energie na mechanick\u00e9 vibrace.  Piezoelektrick\u00e1 metoda je nejroz\u0161\u00ed\u0159en\u011bj\u0161\u00ed d\u00edky sv\u00e9 efektivit\u011b a p\u0159esnosti, zat\u00edmco magnetostrikce je vhodn\u00e1 pro aplikace vy\u017eaduj\u00edc\u00ed vy\u0161\u0161\u00ed v\u00fdkon a ni\u017e\u0161\u00ed frekvence.  R\u016fzn\u00e9 aplikace ultrazvuku vy\u017eaduj\u00ed optimalizaci parametr\u016f gener\u00e1toru, aby se dos\u00e1hlo po\u017eadovan\u00fdch v\u00fdsledk\u016f.  Pokrok v oblasti materi\u00e1l\u016f a elektroniky vede k neust\u00e1l\u00e9mu zlep\u0161ov\u00e1n\u00ed technologi\u00ed generov\u00e1n\u00ed ultrazvuku a roz\u0161i\u0159ov\u00e1n\u00ed jeho pou\u017eit\u00ed v r\u016fzn\u00fdch oblastech.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Ultrazvuk je v\u0161udyp\u0159\u00edtomn\u00fd v modern\u00ed medic\u00edn\u011b, pr\u016fmyslu a dal\u0161\u00edch oblastech. Jeho generov\u00e1n\u00ed je fascinuj\u00edc\u00ed proces, kter\u00fd spo\u010d\u00edv\u00e1 v p\u0159em\u011bn\u011b elektrick\u00e9 energie na mechanick\u00e9 vibrace, a n\u00e1sledn\u011b na zvukov\u00e9 vlny o frekvenci vy\u0161\u0161\u00ed ne\u017e 20 kHz, tedy nad hranic\u00ed sly\u0161itelnosti lidsk\u00e9ho ucha. Tento \u010dl\u00e1nek se podrobn\u011b zam\u011b\u0159\u00ed na principy generov\u00e1n\u00ed ultrazvuku a na r\u016fzn\u00e9 metody, kter\u00e9<\/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-60279","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\/60279","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=60279"}],"version-history":[{"count":0,"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/posts\/60279\/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=60279"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/categories?post=60279"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.bjultrasonic.com\/cs\/wp-json\/wp\/v2\/tags?post=60279"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}