%0 Journal Article
%T Theoretical and experimental study of enhanced subharmonic emission from microbubbles with chirp excitation<br>调频激励增强微气泡的次谐波理论和实验研究
%A Gong Yan-Jun
%A Zhang Dong
%A Xi Xiao-Yu
%A Gong Xiu-Fen
%A Liu Zheng
%A <br>龚燕君
%A 章东
%A 郗晓宇
%A 龚秀芬
%A 刘政
%J 物理学报
%D 2007
%I 
%X Subharmonic contrast imaging provides improved ultrasound imaging quality by taking advantage of increased contrast to tissue ratio. This article presents a novl approach to enhance the subharmonic emission from microbubbles by using a chip excitation technique. The chirp excitation pressure threshold and the sound pessure dependence of subharmonic are theoretically evaluated based on the Churc's model. Measurements validate that the optimized bandwidth and time duration of the chirp excitation can improve subharmonic amplitude and reduce side-lobe level. Both theoretical and experimental results demonstrate that the chirp excitation can improve the amplitude up to 22dB over the pulse excitation at the subharmonic frequency when comparing the coded excitation with traditional pulse excitation.
%K chirp excitation
%K ultrasound contrast agent
%K microbubble
%K subharmonic<br>调频激励
%K 超声造影剂
%K 微气泡
%K 次谐波
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=6E709DC38FA1D09A4B578DD0906875B5B44D4D294832BB8E&cid=47EA7CFDDEBB28E0&jid=29DF2CB55EF687E7EFA80DFD4B978260&aid=1AF38BA7FDD7D1753B3649C081A46113&yid=A732AF04DDA03BB3&vid=014B591DF029732F&iid=59906B3B2830C2C5&sid=4A71C870C8D926F2&eid=2B5C7C5536150C95&journal_id=1000-3290&journal_name=物理学报&referenced_num=0&reference_num=17