{"id":7739,"date":"2017-10-24T00:01:41","date_gmt":"2017-10-23T17:01:41","guid":{"rendered":"http:\/\/ttud.com.vn\/?p=7739"},"modified":"2017-12-04T00:02:20","modified_gmt":"2017-12-03T17:02:20","slug":"sieu-vat-lieu-co-cau-truc-me-cung-giup-giam-o-nhiem-tieng-on","status":"publish","type":"post","link":"https:\/\/casta.ttud.com.vn\/index.php\/sieu-vat-lieu-co-cau-truc-me-cung-giup-giam-o-nhiem-tieng-on\/","title":{"rendered":"Si\u00eau v\u1eadt li\u1ec7u c\u00f3 c\u1ea5u tr\u00fac m\u00ea cung gi\u00fap gi\u1ea3m \u00f4 nhi\u1ec5m ti\u1ebfng \u1ed3n"},"content":{"rendered":"

\"alt\"<\/p>\n

M\u1ed9t nh\u00f3m c\u00e1c nh\u00e0 nghi\u00ean c\u1ee9u g\u1ed3m c\u00e1c nh\u00e0 khoa h\u1ecdc Anastasiia Krushynska v\u00e0 Federico Bosia thu\u1ed9c tr\u01b0\u1eddng \u0110\u1ea1i h\u1ecdc Torino, Marco Miniaci – \u0110\u1ea1i h\u1ecdc Le Havre v\u00e0 Nicola Pugno thu\u1ed9c tr\u01b0\u1eddng \u0110\u1ea1i h\u1ecdc Trento, \u0110\u1ea1i h\u1ecdc Queen Mary \u1edf London, v\u00e0 C\u01a1 quan V\u0169 tr\u1ee5 \u00dd \u0111\u00e3 ch\u1ee9ng minh r\u1eb1ng c\u1ea5u tr\u00fac h\u00ecnh h\u1ecdc c\u1ee7a m\u1ea1ng nh\u1ec7n t\u1ef1 nhi\u00ean c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng \u0111\u1ec3 thi\u1ebft k\u1ebf c\u00e1c c\u1ea5u tr\u00fac m\u1edbi gi\u00fap gi\u1ea3i quy\u1ebft m\u1ed9t trong nh\u1eefng th\u00e1ch th\u1ee9c l\u1edbn nh\u1ea5t trong v\u1ea5n \u0111\u1ec1 ki\u1ec3m so\u00e1t hi\u1ec7n tr\u1ea1ng \u00f4 nhi\u1ec5m \u00e2m thanh, gi\u1ea3m m\u1ee9c \u0111\u1ed9 \u00f4 nhi\u1ec5m ti\u1ebfng \u1ed3n (tr\u1ea7m t\u1ea7n s\u1ed1 th\u1ea5p) v\u1ed1n \u0111\u01b0\u1ee3c coi l\u00e0 v\u1ea5n \u0111\u1ec1 m\u00f4i tr\u01b0\u1eddng th\u1ee9 hai lan r\u1ed9ng \u1edf ch\u00e2u \u00c2u sau khi \u00f4 nhi\u1ec5m kh\u00f4ng kh\u00ed.<\/p>\n

Pugno cho bi\u1ebft: C\u00f4ng tr\u00ecnh nghi\u00ean c\u1ee9u \u0111\u1ec1 xu\u1ea5t m\u1ed9t ph\u01b0\u01a1ng ph\u00e1p ti\u1ebfp c\u1eadn m\u1edbi \u0111\u1ea7y h\u1ee9a h\u1eb9n nh\u1eb1m gi\u1ea3m thi\u1ec3u t\u00ecnh tr\u1ea1ng \u00f4 nhi\u1ec5m ti\u1ebfng \u1ed3n t\u1ea7n s\u1ed1 th\u1ea5p. C\u1ee5 th\u1ec3, nh\u00f3m nghi\u00ean c\u1ee9u \u0111\u00e3 thi\u1ebft k\u1ebf ra m\u1ed9t lo\u1ea1i si\u00eau v\u1eadt li\u1ec7u (metamaterials) – lo\u1ea1i v\u1eadt ch\u1ea5t nh\u00e2n t\u1ea1o c\u00f3 kh\u1ea3 n\u0103ng k\u1ebft h\u1ee3p nh\u1eefng \u01b0u \u0111i\u1ec3m c\u1ee7a c\u1ea5u tr\u00fac h\u00ecnh h\u1ecdc gi\u1ed1ng nh\u01b0 t\u01a1 nh\u1ec7n v\u1edbi h\u01b0\u1edbng ti\u1ebfp c\u1eadn xo\u1eafn kh\u00f4ng gian c\u1ee7a c\u00e1c r\u00e3nh m\u00ea cung. C\u1ea5u tr\u00fac m\u1edbi g\u1ee3i m\u1edf ra ph\u01b0\u01a1ng th\u1ee9c \u0111\u01a1n gi\u1ea3n v\u00e0 \u0111\u00e1ng tin c\u1eady, c\u00f3 t\u00ednh kh\u1ea3 thi trong thao t\u00e1c ch\u1ec9nh \u00e2m thanh, \u0111i\u1ec1u n\u00e0y r\u1ea5t c\u1ea7n thi\u1ebft \u0111\u1ed1i v\u1edbi c\u00e1c \u1ee9ng d\u1ee5ng th\u1ef1c ti\u1ec5n.<\/p>\n

\u00c2m thanh t\u1ea7n s\u1ed1 th\u1ea5p \u0111\u01b0\u1ee3c \u0111\u1eb7c tr\u01b0ng b\u1edfi c\u00e1c b\u01b0\u1edbc s\u00f3ng d\u00e0i, do \u0111\u00f3, vi\u1ec7c che ch\u1eafn, h\u1ea1n ch\u1ebf c\u00e1c s\u00f3ng \u00e2m n\u00e0y th\u01b0\u1eddng \u0111\u00f2i h\u1ecfi s\u1eed d\u1ee5ng nh\u1eefng lo\u1ea1i v\u1eadt li\u1ec7u c\u00f3 c\u1ea5u tr\u00fac ch\u1eafc ch\u1eafn, d\u00e0y v\u00e0 tr\u1ecdng l\u01b0\u1ee3ng l\u1edbn, chi ph\u00ed t\u1ed1n k\u00e9m v\u00e0 \u0111\u1eb7c bi\u1ec7t l\u00e0 kh\u00f4ng d\u1ec5 \u00e1p d\u1ee5ng \u0111\u1ed1i v\u1edbi h\u1ea7u h\u1ebft c\u00e1c \u1ee9ng d\u1ee5ng.<\/p>\n

Trong nghi\u00ean c\u1ee9u, c\u00e1c nh\u00e0 khoa h\u1ecdc \u0111\u00e3 ph\u00e1t minh ra m\u1ed9t ph\u01b0\u01a1ng ph\u00e1p ti\u1ebfp c\u1eadn kh\u00e1c trong \u0111\u00f3 h\u1ecd s\u1eed d\u1ee5ng nh\u1eefng lo\u1ea1i si\u00eau v\u1eadt li\u1ec7u m\u1edbi \u0111\u01b0\u1ee3c ph\u00e1t tri\u1ec3n g\u1ea7n \u0111\u00e2y. Trong khi hi\u1ec7u qu\u1ea3 \u0111i\u1ec1u ch\u1ec9nh \u00e2m thanh b\u1eb1ng t\u1ea5m c\u00e1ch \u00e2m ch\u1ed1ng \u1ed3n th\u00f4ng th\u01b0\u1eddng ch\u1ee7 y\u1ebfu d\u1ef1a v\u00e0o c\u1ea5u t\u1ea1o v\u00e0 \u0111\u1ed9 d\u00e0y c\u1ee7a v\u1eadt li\u1ec7u th\u00ec \u0111\u1ed1i v\u1edbi c\u00e1c si\u00eau v\u1eadt li\u1ec7u, c\u1ea5u tr\u00fac subwavelength-scale ph\u1ee9c t\u1ea1p \u0111\u00f3ng vai tr\u00f2 quy\u1ebft \u0111\u1ecbnh. K\u1ebft qu\u1ea3 l\u00e0, metamaterials tuy c\u00f3 c\u1ea5u t\u1ea1o r\u1ea5t m\u1ecfng nh\u01b0ng hi\u1ec7u qu\u1ea3 c\u00e1ch \u00e2m c\u0169ng nh\u01b0 kh\u1ea3 n\u0103ng \u0111i\u1ec1u ch\u1ec9nh \u00e2m thanh \u00e2m thanh t\u1ea7n s\u1ed1 th\u1ea5p c\u1ee7a n\u00f3 l\u1ea1i r\u1ea5t cao.<\/p>\n

Trong nghi\u00ean c\u1ee9u m\u1edbi, thi\u1ebft k\u1ebf m\u1edbi d\u1ef1a tr\u00ean m\u1ed9t kh\u00e1i ni\u1ec7m m\u1edbi c\u00f3 t\u00ean g\u1ecdi l\u00e0 metamaterials m\u00ea cung ho\u1eb7c “cu\u1ed9n kh\u00f4ng gian” \u0111\u01b0\u1ee3c \u0111\u1ec1 xu\u1ea5t l\u1ea7n \u0111\u1ea7u ti\u00ean v\u00e0i n\u0103m tr\u01b0\u1edbc \u0111\u00e2y. V\u1eadt li\u1ec7u m\u1edbi \u0111\u01b0\u1ee3c c\u1ea5u th\u00e0nh b\u1edfi c\u00e1c r\u00e3nh h\u00ecnh zig-zag \u0111\u01b0\u1ee3c u\u1ed1n ch\u1eadp c\u00e1c k\u00eanh lu\u00e2n chuy\u1ec3n v\u1edbi nhau, cho h\u1ecd m\u1ed9t h\u00ecnh d\u1ea1ng gi\u1ed1ng nh\u01b0 m\u00ea cung.<\/p>\n

Si\u00eau v\u1eadt li\u1ec7u c\u00f3 c\u1ea5u tr\u00fac m\u00ea cung \u0111\u01b0\u1ee3c c\u1ea5u h\u00ecnh d\u01b0\u1edbi d\u1ea1ng c\u1ea5u tr\u00fac m\u1ed9t m\u1ea1ng nh\u1ec7n. C\u00e1c chuy\u00ean gia cho bi\u1ebft c\u1ea5u tr\u00fac h\u00ecnh h\u1ecdc n\u00e0y \u0111\u1eb7c bi\u1ec7t hi\u1ec7u qu\u1ea3 trong vi\u1ec7c l\u00e0m suy y\u1ebfu (ho\u1eb7c l\u00e0m gi\u1ea3m c\u01b0\u1eddng \u0111\u1ed9) c\u1ee7a c\u00e1c s\u00f3ng c\u01a1 h\u1ecdc (s\u00f3ng \u0111\u00e0n h\u1ed3i). Trong nghi\u00ean c\u1ee9u m\u1edbi, c\u00e1c nh\u00e0 khoa h\u1ecdc \u0111\u00e3 thay \u0111\u1ed5i thi\u1ebft k\u1ebf c\u1ee7a si\u00eau v\u1eadt li\u1ec7u m\u00ea cung \u0111\u00e3 \u0111\u01b0\u1ee3c \u0111\u1ec1 xu\u1ea5t tr\u01b0\u1edbc \u0111\u00f3 b\u1eb1ng c\u00e1ch th\u00eam m\u1ed9t khung h\u00ecnh vu\u00f4ng, khi\u1ebfn cho c\u1ea5u tr\u00fac c\u1ee7a v\u1eadt li\u1ec7u gi\u1ed1ng v\u1edbi c\u1ea5u tr\u00fac c\u1ee7a m\u1ed9t m\u1ea1ng nh\u1ec7n trong t\u1ef1 nhi\u00ean. Ch\u00ednh s\u1ef1 thay \u0111\u1ed5i t\u01b0\u1edfng ch\u1eebng h\u1ebft s\u1ee9c \u0111\u01a1n gi\u1ea3n n\u00e0y \u0111\u00e3 g\u00f3p ph\u1ea7n t\u1ea1o ra c\u00e1c l\u1ed7 h\u1ed5ng kh\u00f4ng kh\u00ed, chi\u1ec1u r\u1ed9ng c\u1ee7a c\u00e1c r\u00e3nh c\u0169ng nh\u1edd \u0111\u00f3 c\u00f3 th\u1ec3 bi\u1ebfn \u0111\u1ed5i linh ho\u1ea1t. C\u00e1c nh\u00e0 nghi\u00ean c\u1ee9u kh\u1eb3ng \u0111\u1ecbnh c\u00f3 th\u1ec3 \u0111i\u1ec1u ch\u1ec9nh c\u00e1c \u0111\u1eb7c tr\u01b0ng \u00e2m thanh c\u1ee7a si\u00eau v\u1eadt li\u1ec7u, bao g\u1ed3m hi\u1ec7n t\u01b0\u1ee3ng t\u00e1n \u00e2m v\u00e0 ph\u1ea3n x\u1ea1 s\u00f3ng \u00e2m th\u00f4ng qua \u0111i\u1ec1u ch\u1ec9nh chi\u1ec1u r\u1ed9ng c\u1ee7a r\u00e3nh.<\/p>\n

Nh\u00f3m nghi\u00ean c\u1ee9u hy v\u1ecdng r\u1eb1ng, lo\u1ea1i si\u00eau v\u1eadt li\u1ec7u c\u00f3 c\u1ea5u tr\u00fac m\u1ea1ng nh\u1ec7n \u0111\u01b0\u1ee3c thi\u1ebft k\u1ebf b\u1eb1ng nh\u00f4m, c\u00f3 th\u1ec3 d\u1ec5 d\u00e0ng ch\u1ebf t\u1ea1o s\u1ebd tr\u1edf n\u00ean h\u1eefu \u00edch v\u00e0 \u0111\u01b0\u1ee3c \u1ee9ng d\u1ee5ng r\u1ed9ng r\u00e3i trong c\u00e1c c\u00f4ng ngh\u1ec7 \u0111i\u1ec1u ch\u1ec9nh \u00e2m thanh t\u1ea7n s\u1ed1 th\u1ea5p.<\/p>\n

\u00d4ng Pugno gi\u1ea3i th\u00edch: M\u1eb7c d\u00f9 vi\u1ec7c \u00e1p d\u1ee5ng c\u1ea5u tr\u00fac h\u00ecnh h\u1ecdc t\u01b0\u01a1ng t\u1ef1 \u0111\u01b0\u1ee3c coi l\u00e0 nh\u1eefng gi\u1ea3i ph\u00e1p \u0111\u1ea7y h\u1ee9a h\u1eb9n nh\u1eb1m l\u00e0m gi\u1ea3m thi\u1ec3u c\u1ee7a s\u1ef1 rung \u0111\u1ed9ng c\u1ee7a \u00e2m thanh t\u1ea7n s\u1ed1 th\u1ea5p. C\u00e1c si\u00eau v\u1eadt li\u1ec7u \u0111\u00e3 \u0111\u01b0\u1ee3c ph\u00e1t tri\u1ec3n kh\u00f4ng th\u1ec3 \u00e1p d\u1ee5ng tr\u1ef1c ti\u1ebfp nh\u01b0 m\u1ed9t gi\u1ea3i ph\u00e1p che ch\u1eafn \u0111\u1ecba ch\u1ea5n, v\u00ec ch\u00fang c\u00f3 kh\u1ea3 n\u0103ng \u0111i\u1ec1u ch\u1ec9nh s\u00f3ng \u00e2m (trong \u0111i\u1ec1u ki\u1ec7n \u1edf tr\u00ean kh\u00f4ng) v\u00e0 s\u00f3ng kh\u00f4ng \u0111\u00e0n h\u1ed3i. Th\u00f4ng th\u01b0\u1eddng, lo\u1ea1i v\u1eadt li\u1ec7u n\u00e0y \u0111\u01b0\u1ee3c l\u1ef1a ch\u1ecdn s\u1eed d\u1ee5ng cho c\u00e1c \u1ee9ng d\u1ee5ng nh\u1eb1m ki\u1ec3m so\u00e1t ti\u1ebfng \u1ed3n \u00e2m thanh t\u1ea7n s\u1ed1 th\u1ea5p ho\u1eb7c \u0111\u1ec3 t\u00e1ch t\u1ea1p \u00e2m v\u1ed1n \u0111\u01b0\u1ee3c coi l\u00e0 nh\u1eefng th\u00e1ch th\u1ee9c \u0111\u1ed1i v\u1edbi c\u00e1c ph\u01b0\u01a1ng ph\u00e1p ti\u1ebfp c\u1eadn truy\u1ec1n th\u1ed1ng, c\u0169ng nh\u01b0 c\u00e1c ph\u01b0\u01a1ng th\u1ee9c \u0111i\u1ec1u ch\u1ec9nh \u00e2m thanh chuy\u1ec3n \u0111\u1ed5i v\u00e0 h\u1ed9i t\u1ee5 \u00e2m thanh \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong c\u00e1c ph\u00f2ng h\u00f2a nh\u1ea1c.<\/p>\n

\u00a0(NASATI)<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"

M\u1ed9t nh\u00f3m c\u00e1c nh\u00e0 nghi\u00ean c\u1ee9u g\u1ed3m c\u00e1c nh\u00e0 khoa h\u1ecdc Anastasiia Krushynska v\u00e0 Federico Bosia thu\u1ed9c tr\u01b0\u1eddng \u0110\u1ea1i h\u1ecdc Torino, Marco Miniaci – \u0110\u1ea1i h\u1ecdc Le Havre v\u00e0 Nicola Pugno thu\u1ed9c tr\u01b0\u1eddng \u0110\u1ea1i h\u1ecdc Trento, \u0110\u1ea1i h\u1ecdc Queen Mary \u1edf London, v\u00e0 C\u01a1 quan V\u0169 tr\u1ee5 \u00dd \u0111\u00e3 ch\u1ee9ng minh r\u1eb1ng c\u1ea5u tr\u00fac h\u00ecnh […]<\/p>\n","protected":false},"author":18,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[47],"tags":[],"class_list":["post-7739","post","type-post","status-publish","format-standard","hentry","category-tin-tuc"],"_links":{"self":[{"href":"https:\/\/casta.ttud.com.vn\/index.php\/wp-json\/wp\/v2\/posts\/7739","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\/18"}],"replies":[{"embeddable":true,"href":"https:\/\/casta.ttud.com.vn\/index.php\/wp-json\/wp\/v2\/comments?post=7739"}],"version-history":[{"count":1,"href":"https:\/\/casta.ttud.com.vn\/index.php\/wp-json\/wp\/v2\/posts\/7739\/revisions"}],"predecessor-version":[{"id":7740,"href":"https:\/\/casta.ttud.com.vn\/index.php\/wp-json\/wp\/v2\/posts\/7739\/revisions\/7740"}],"wp:attachment":[{"href":"https:\/\/casta.ttud.com.vn\/index.php\/wp-json\/wp\/v2\/media?parent=7739"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/casta.ttud.com.vn\/index.php\/wp-json\/wp\/v2\/categories?post=7739"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/casta.ttud.com.vn\/index.php\/wp-json\/wp\/v2\/tags?post=7739"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}