{"id":5964,"date":"2017-07-10T19:06:12","date_gmt":"2017-07-10T12:06:12","guid":{"rendered":"http:\/\/ttud.com.vn\/?p=5964"},"modified":"2017-10-03T10:18:25","modified_gmt":"2017-10-03T03:18:25","slug":"ky-thuat-quang-am-moi-co-the-phat-hien-chat-khi-co-nong-do-cuc-ky-thap","status":"publish","type":"post","link":"https:\/\/casta.ttud.com.vn\/index.php\/ky-thuat-quang-am-moi-co-the-phat-hien-chat-khi-co-nong-do-cuc-ky-thap\/","title":{"rendered":"K\u1ef9 thu\u1eadt quang \u00e2m m\u1edbi c\u00f3 th\u1ec3 ph\u00e1t hi\u1ec7n ch\u1ea5t kh\u00ed c\u00f3 n\u1ed3ng \u0111\u1ed9 c\u1ef1c k\u1ef3 th\u1ea5p"},"content":{"rendered":"

Nh\u00f3m nghi\u00ean c\u1ee9u h\u1ee3p t\u00e1c c\u1ee7a Tr\u01b0\u1eddng \u0110\u1ea1i h\u1ecdc Brown v\u00e0 Tr\u01b0\u1eddng \u0110\u1ea1i h\u1ecdc S\u01a1n \u0110\u00f4ng (Trung Qu\u1ed1c) \u0111\u00e3 t\u00ecm ra \u0111\u01b0\u1ee3c m\u1ed9t ph\u01b0\u01a1ng ph\u00e1p c\u00f3 th\u1ec3 ph\u00e1t hi\u1ec7n c\u00e1c kh\u00ed th\u1ea3i c\u00f3 n\u1ed3ng \u0111\u1ed9 d\u01b0\u1edbi m\u1ee9c ppq (1 ph\u1ea7n tri\u1ec7u t\u1ef7) b\u1eb1ng c\u00e1ch s\u1eed d\u1ee5ng m\u1ed9t bi\u1ebfn th\u1ec3 m\u1edbi d\u1ef1a tr\u00ean hi\u1ec7u \u1ee9ng quang – \u00e2m (photoacoustic), m\u1ed9t ph\u01b0\u01a1ng ph\u00e1p k\u1ef9 thu\u1eadt d\u00f9ng \u0111\u1ec3 \u0111o \u00e2m thanh ph\u00e1t ra khi \u00e1nh s\u00e1ng t\u01b0\u01a1ng t\u00e1c v\u1edbi c\u00e1c ph\u00e2n t\u1eed.<\/strong><\/p>\n

\"\"<\/p>\n

\u201cHi\u1ec7u \u1ee9ng quang – \u00e2m l\u00e0 m\u1ed9t ph\u01b0\u01a1ng ph\u00e1p s\u1eb5n c\u00f3 r\u1ea5t h\u1eefu d\u1ee5ng d\u00f9ng \u0111\u1ec3 ph\u00e1t hi\u1ec7n c\u00e1c ch\u1ea5t g\u00e2y \u00f4 nhi\u1ec5m trong b\u1ea7u kh\u00ed quy\u1ec3n. Tuy nhi\u00ean, khi n\u1ed3ng \u0111\u1ed9 c\u1ee7a c\u00e1c ph\u00e2n t\u1eed trong ch\u1ea5t n\u00e0o \u0111\u00f3 \u1edf d\u01b0\u1edbi m\u1ee9c 1 ph\u1ea7n ngh\u00ecn t\u1ef7 (ppt) th\u00ec s\u1ebd r\u1ea5t kh\u00f3 kh\u0103n \u0111\u1ec3 c\u00f3 th\u1ec3 ph\u00e1t hi\u1ec7n ra. K\u1ef9 thu\u1eadt quang \u00e2m m\u1edbi n\u00e0y, do ch\u00fang t\u00f4i ph\u00e1t tri\u1ec3n, c\u00f3 th\u1ec3 l\u00e0m gia t\u0103ng c\u00e1c t\u00edn hi\u1ec7u ph\u00e1t hi\u1ec7n v\u00e0 t\u1eeb \u0111\u00f3 c\u00f3 th\u1ec3 cho ph\u00e9p ch\u00fang t\u00f4i t\u00ecm ra \u0111\u01b0\u1ee3c c\u00e1c ch\u1ea5t \u00f4 nhi\u1ec5m c\u00f3 n\u1ed3ng \u0111\u1ed9 d\u01b0\u1edbi m\u1ee9c 1 ph\u1ea7n tri\u1ec7u t\u1ef7 (ppq). Con s\u1ed1 n\u00e0y \u0111\u01b0\u1ee3c xem l\u00e0 m\u1ed9t k\u1ef7 l\u1ee5c m\u1edbi\u201d, Gerald Diebold, gi\u00e1o s\u01b0 h\u00f3a h\u1ecdc t\u1ea1i \u0110\u1ea1i h\u1ecdc Brown v\u00e0 \u0111\u1ed3ng t\u00e1c gi\u1ea3 nghi\u00ean c\u1ee9u cho bi\u1ebft.<\/p>\n

C\u00f4ng tr\u00ecnh nghi\u00ean c\u1ee9u \u0111\u00e3 \u0111\u01b0\u1ee3c nh\u00f3m nghi\u00ean c\u1ee9u ph\u00f2ng th\u00ed nghi\u1ec7m Diebol (\u0110\u1ea1i h\u1ecdc Brown) v\u00e0 ph\u00f2ng th\u00ed nghi\u1ec7m Fapeng Yu ( \u0110\u1ea1i h\u1ecdc S\u01a1n \u0110\u00f4ng) c\u00f4ng b\u1ed1 tr\u00ean t\u1ea1p ch\u00ed Proceedings of the National Academy of Sciences g\u1ea7n \u0111\u00e2y.<\/p>\n

Hi\u1ec7u \u1ee9ng quang \u00e2m x\u1ea3y ra khi m\u1ed9t ch\u00f9m \u00e1nh s\u00e1ng ph\u00e1t ra \u0111\u01b0\u1ee3c h\u1ea5p th\u1ee5 b\u1edfi ch\u1ea5t kh\u00ed, l\u1ecfng ho\u1eb7c r\u1eafn khi\u1ebfn c\u00e1c ch\u1ea5t n\u00e0y b\u1ecb ph\u1ed3ng n\u1edf r\u1ed9ng ra. S\u1ef1 n\u1edf r\u1ed9ng n\u00e0y, l\u00e0 m\u1ed9t chuy\u1ec3n \u0111\u1ed9ng c\u01a1 h\u1ecdc, s\u1ebd khi\u1ebfn cho n\u00f3 t\u1ea1o ra c\u00e1c s\u00f3ng \u00e2m. Hi\u1ec7u \u1ee9ng n\u00e0y, l\u1ea7n \u0111\u1ea7u ti\u00ean \u0111\u01b0\u1ee3c ph\u00e1t hi\u1ec7n b\u1edfi nh\u00e0 khoa h\u1ecdc Alexander Graham Bell v\u00e0o th\u1eadp k\u1ef7 nh\u01b0ng n\u00f3 \u00edt c\u00f3 gi\u00e1 tr\u1ecb th\u1ef1c ti\u1ec5n cho \u0111\u1ebfn khi c\u00e1c nh\u00e0 khoa h\u1ecdc ph\u00e1t minh ra tia laser, c\u00f3 th\u1ec3 khi\u1ebfn cho c\u00e1c t\u00edn hi\u1ec7u quang \u00e2m tr\u1edf n\u00ean\u201c\u0111\u1ee7 l\u1edbn\u201d \u0111\u1ec3 c\u00f3 th\u1ec3 d\u1ec5 d\u00e0ng b\u1ecb ph\u00e1t hi\u1ec7n.<\/p>\n

Thi\u1ebft b\u1ecb d\u00f2 quang \u00e2m ho\u1ea1t \u0111\u1ed9ng b\u1eb1ng c\u00e1ch bi\u1ebfn \u0111\u1ed5i v\u1eadt li\u1ec7u b\u1eb1ng tia laser \u0111\u00e3 \u0111\u01b0\u1ee3c \u0111i\u1ec1u ch\u1ec9nh b\u01b0\u1edbc s\u00f3ng th\u00edch h\u1ee3p \u0111\u1ec3 h\u1ea5p th\u1ee5 c\u00e1c ph\u00e2n t\u1eed c\u1ea7n thi\u1ebft. Trong m\u1ed9t th\u00ed nghi\u1ec7m quang \u00e2m \u0111i\u1ec3n h\u00ecnh, ch\u00f9m tia laser \u0111\u01b0\u1ee3c b\u1eadt, t\u1eaft \u1edf t\u1ea7n s\u1ed1 m\u00e1y vi \u00e2m c\u1ea3m bi\u1ebfn c\u00f3 th\u1ec3 ph\u00e1t hi\u1ec7n \u0111\u01b0\u1ee3c b\u1ea5t k\u1ef3 s\u00f3ng \u00e2m thanh n\u00e0o ph\u00e1t ra. C\u00e1c ph\u00e2n t\u1eed kh\u00e1c nhau h\u1ea5p th\u1ee5 \u00e1nh s\u00e1ng \u1edf c\u00e1c m\u1ee9c t\u1ea7n s\u1ed1 kh\u00e1c nhau, do \u0111\u00f3 b\u1eb1ng c\u00e1ch \u0111i\u1ec1u ch\u1ec9nh t\u1ea7n s\u1ed1 c\u1ee7a tia laser, s\u1ebd c\u00f3 th\u1ec3 tinh ch\u1ec9nh m\u00e1y d\u00f2 cho t\u1eebng ch\u1ea5t c\u1ee5 th\u1ec3. V\u00ed d\u1ee5 nh\u01b0, \u0111\u1ec3 t\u00ecm ammoniac trong kh\u00f4ng kh\u00ed, laser s\u1ebd \u0111\u01b0\u1ee3c \u0111i\u1ec1u ch\u1ec9nh theo t\u1ea7n s\u1ed1 h\u1ea5p th\u1ee5 \u0111\u1eb7c tr\u01b0ng c\u1ee7a c\u00e1c ph\u00e2n t\u1eed amoniac. Tuy nhi\u00ean, s\u1ebd r\u1ea5t kh\u00f3 d\u00f2 t\u00ecm \u0111\u01b0\u1ee3c t\u00edn hi\u1ec7u c\u1ee7a ch\u1ea5t n\u00e0o \u0111\u00f3 khi n\u1ed3ng \u0111\u1ed9 c\u1ee7a ch\u1ea5t \u0111\u00f3 \u1edf m\u1ee9c r\u1ea5t nh\u1ecf, v\u00ec v\u1eady, \u0111\u1ec3 c\u00f3 th\u1ec3 ph\u00e1t hi\u1ec7n \u0111\u01b0\u1ee3c c\u00e1c ch\u1ea5t n\u00e0o \u0111\u00f3 d\u00f9 ch\u1ec9 c\u00f3 n\u1ed3ng \u0111\u1ed9 r\u1ea5t nh\u1ecf, Diebold v\u00e0 c\u00e1c \u0111\u1ed3ng nghi\u1ec7p \u0111\u00e3 d\u00f9ng m\u1ed9t k\u1ef9 thu\u1eadt \u0111\u1ed9c \u0111\u00e1o \u0111\u1ec3 c\u00f3 th\u1ec3 t\u0103ng bi\u00ean \u0111\u1ed9 t\u00edn hi\u1ec7u ph\u00e1t hi\u1ec7n.<\/p>\n

Theo Diebold cho bi\u1ebft, \u201cTh\u1ee9 m\u00e0 ch\u00fang t\u00f4i t\u1ea1o ra \u0111\u01b0\u1ee3c \u0111\u00f3 l\u00e0 ph\u00e1t minh ra \u0111\u01b0\u1ee3c m\u1ed9t ph\u01b0\u01a1ng ph\u00e1p c\u00f3 th\u1ec3 d\u1ef1a v\u00e0o 3 c\u1ed9ng h\u01b0\u1edfng khau nhau \u0111\u1ec3 t\u00ecm ra t\u00edn hi\u1ec7u ch\u1ea5t. V\u1edbi m\u1ed7i c\u1ed9ng h\u01b0\u1edfng, t\u00edn hi\u1ec7u s\u1ebd \u0111\u01b0\u1ee3c khu\u1ebfch \u0111\u1ea1i l\u1edbn d\u1ea7n l\u00ean\u201d.<\/p>\n

Thay v\u00ec ch\u1ec9 s\u1eed d\u1ee5ng m\u1ed9t ch\u00f9m laser \u0111\u01a1n, Diebold v\u00e0 c\u00e1c \u0111\u1ed3ng nghi\u1ec7p c\u1ee7a \u00f4ng k\u1ebft h\u1ee3p hai ch\u00f9m laser c\u00f3 t\u1ea7n s\u1ed1 v\u00e0 g\u00f3c r\u1ea5t \u0111\u1eb7c bi\u1ec7t. S\u1ef1 k\u1ebft h\u1ee3p c\u1ee7a hai ch\u00f9m n\u00e0y \u0111\u00e3 t\u1ea1o ra m\u1ed9t m\u1ea1ng l\u01b0\u1edbi – m\u1ed9t ki\u1ec3u giao thoa – gi\u1eefa hai ch\u00f9m laser. Khi t\u1ea7n s\u1ed1 laser \u0111\u01b0\u1ee3c \u0111i\u1ec1u ch\u1ec9nh \u0111\u00fang, m\u1ea1ng l\u01b0\u1edbi n\u00e0y s\u1ebd lan truy\u1ec1n trong ph\u1ea1m vi t\u1ebf b\u00e0o c\u00f3 th\u1ec3 ph\u00e1t hi\u1ec7n v\u1edbi t\u1ed1c \u0111\u1ed9 \u00e2m thanh, t\u1ea1o ra m\u1ed9t hi\u1ec7u \u1ee9ng khuy\u1ebfn \u0111\u1ea1i \u1edf m\u1ed7i \u0111\u1ec9nh c\u1ed9ng h\u01b0\u1edfng trong m\u1ea1ng l\u01b0\u1edbi n\u00e0y.<\/p>\n

C\u1ed9ng h\u01b0\u1edfng th\u1eed hai \u0111\u01b0\u1ee3c t\u1ea1o ra b\u1edfi tinh th\u1ec3 \u00e1p \u0111i\u1ec7n (piezoelectric). Tinh th\u1ec3 n\u00e0y c\u00f3 th\u1ec3 t\u1ea1o rung ch\u00ednh x\u00e1c \u1edf t\u1ea7n s\u1ed1 c\u1ee7a c\u00e1c tia laser k\u1ebft h\u1ee3p.<\/p>\n

C\u1ed9ng h\u01b0\u1edfng th\u1ee9 3 \u0111\u01b0\u1ee3c t\u1ea1o ra b\u1eb1ng c\u00e1ch \u0111i\u1ec1u ch\u1ec9nh b\u1ec1 r\u1ed9ng l\u1ed7 h\u1ed5ng \u1edf trong tinh th\u1ec3 \u0111\u01b0\u1ee3c g\u1eafn k\u1ebft \u0111\u1ec3 n\u00f3 t\u1ea1o ra c\u1ed9ng h\u01b0\u1edfng khi m\u1ed9t s\u1ed1 nguy\u00ean n\u1eeda \u0111\u1ed9 d\u00e0i b\u01b0\u1edbc s\u00f3ng c\u1ee7a \u00e2m thanh b\u1eb1ng v\u1edbi \u0111\u1ed9 d\u00e0i c\u1ee7a l\u1ed7 h\u1ed5ng. N\u00f3 ph\u00e1t ra \u0111i\u1ec7n \u00e1p t\u1ef7 l\u1ec7 v\u1edbi s\u1ef1 dao \u0111\u1ed9ng c\u1ee7a n\u00f3, v\u00e0 g\u1eedi t\u00edn hi\u1ec7u \u00e2m thanh c\u1ea7n ghi l\u1ea1i \u0111\u1ebfn b\u1ed9 khu\u1ebfch \u0111\u1ea1i v\u00e0 thi\u1ebft b\u1ecb c\u1ea3m bi\u1ebfn \u0111i\u1ec7n t\u1eed.<\/p>\n

\u201cM\u1ed9t trong nh\u1eefng l\u00fd do \u0111\u1ec3 ph\u01b0\u01a1ng ph\u00e1p d\u1ea1ng l\u01b0\u1edbi ho\u1ea1t \u0111\u1ed9ng n\u00e0y l\u00e0m vi\u1ec7c t\u1ed1t l\u00e0 do nh\u00f3m nghi\u00ean c\u1ee9u c\u1ee7a gi\u00e1o su Yu, \u0110\u1ea1i h\u1ecdc S\u01a1n \u0110\u00f4ng \u0111\u00e3 ph\u00e1t tri\u1ec3n \u0111\u01b0\u1ee3c m\u1ed9t tinh th\u1ec3 \u0111\u1eb7c bi\u1ec7t c\u00f3 th\u1ec3 nh\u1eadn \u0111\u01b0\u1ee3c t\u00edn hi\u1ec7u l\u1edbn trong ph\u1ea3n \u1ee9ng v\u1edbi s\u00f3ng \u00e1p l\u1ef1c. H\u1ecd \u0111\u00e3 m\u1ea5y 3 th\u00e1ng \u0111\u1ec3 t\u1ed5ng h\u1ee3p tinh th\u1ec3 n\u00e0y\u201d, Diebold n\u00f3i.<\/p>\n

Trong th\u00ed nghi\u1ec7m nghi\u00ean c\u1ee9u n\u00e0y, c\u00e1c nh\u00e0 nghi\u00ean c\u1ee9u cho th\u1ea5y b\u1eb1ng vi\u1ec7c s\u1eed d\u1ee5ng 3 c\u1ed9ng h\u01b0\u1edfng n\u00e0y h\u1ecd c\u00f3 th\u1ec3 ph\u00e1t hi\u1ec7n ra kh\u00ed hexafluorua l\u01b0u hu\u1ef3nh v\u1edbi n\u1ed3ng \u0111\u1ed9 ch\u1ea5t d\u01b0\u1edbi 1 ph\u1ea7n tri\u1ec7u t\u1ef7.<\/p>\n

Diebold cho r\u1eb1ng k\u1ef9 thu\u1eadt n\u00e0y s\u1ebd h\u1eefu \u00edch trong vi\u1ec7c ph\u00e1t tri\u1ec3n c\u00e1c m\u00e1y d\u00f2 c\u1ea3m bi\u1ebfn ph\u00e1t hi\u1ec7n ra c\u00e1c ch\u1ea5t g\u00e2y \u00f4 nhi\u1ec5m c\u00f3 n\u1ed3ng \u0111\u1ed9 r\u1ea5t th\u1ea5p, ho\u1eb7c ph\u00e1t hi\u1ec7n ra c\u00e1c ph\u00e2n t\u1eed c\u00f3 kh\u1ea3 n\u0103ng h\u1ea5p th\u1ee5 y\u1ebfu v\u00e0 r\u1ea5t kh\u00f3 ph\u00e1t hi\u1ec7n.<\/p>\n

P.T.T (NASATI), Theo https:\/\/phys.org\/news\/2017-06-photoacoustic-technique-gases-parts-per-quadrillion.html, 28\/6\/2017<\/em><\/p>\n

Ngu\u1ed3n Vista<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"

Nh\u00f3m nghi\u00ean c\u1ee9u h\u1ee3p t\u00e1c c\u1ee7a Tr\u01b0\u1eddng \u0110\u1ea1i h\u1ecdc Brown v\u00e0 Tr\u01b0\u1eddng \u0110\u1ea1i h\u1ecdc S\u01a1n \u0110\u00f4ng (Trung Qu\u1ed1c) \u0111\u00e3 t\u00ecm ra \u0111\u01b0\u1ee3c m\u1ed9t ph\u01b0\u01a1ng ph\u00e1p c\u00f3 th\u1ec3 ph\u00e1t hi\u1ec7n c\u00e1c kh\u00ed th\u1ea3i c\u00f3 n\u1ed3ng \u0111\u1ed9 d\u01b0\u1edbi m\u1ee9c ppq (1 ph\u1ea7n tri\u1ec7u t\u1ef7) b\u1eb1ng c\u00e1ch s\u1eed d\u1ee5ng m\u1ed9t bi\u1ebfn th\u1ec3 m\u1edbi d\u1ef1a tr\u00ean hi\u1ec7u \u1ee9ng quang […]<\/p>\n","protected":false},"author":17,"featured_media":6478,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[47],"tags":[],"class_list":["post-5964","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-tin-tuc"],"_links":{"self":[{"href":"https:\/\/casta.ttud.com.vn\/index.php\/wp-json\/wp\/v2\/posts\/5964","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/casta.ttud.com.vn\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/casta.ttud.com.vn\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/casta.ttud.com.vn\/index.php\/wp-json\/wp\/v2\/users\/17"}],"replies":[{"embeddable":true,"href":"https:\/\/casta.ttud.com.vn\/index.php\/wp-json\/wp\/v2\/comments?post=5964"}],"version-history":[{"count":2,"href":"https:\/\/casta.ttud.com.vn\/index.php\/wp-json\/wp\/v2\/posts\/5964\/revisions"}],"predecessor-version":[{"id":6479,"href":"https:\/\/casta.ttud.com.vn\/index.php\/wp-json\/wp\/v2\/posts\/5964\/revisions\/6479"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/casta.ttud.com.vn\/index.php\/wp-json\/wp\/v2\/media\/6478"}],"wp:attachment":[{"href":"https:\/\/casta.ttud.com.vn\/index.php\/wp-json\/wp\/v2\/media?parent=5964"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/casta.ttud.com.vn\/index.php\/wp-json\/wp\/v2\/categories?post=5964"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/casta.ttud.com.vn\/index.php\/wp-json\/wp\/v2\/tags?post=5964"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}