logo

korean english

게시판

Home > 게시판 > 세미나

아래와 같이 콜로퀴움을 개최하오니 많이 참석해 주시기 바랍니다.

4시 20분부터 제1과학관 31214 e+강의실에서 다과를 준비하오니 많은 참석 부탁드립니다

 

아 래

 

제목: 청각의 물리학: 어떻게 노이즈를 극복하는가?

  

연사: 안  강  헌 교수님 (충남대학교, 물리학과)

 

일시: 2013년 9월 25일(수) 오후4:30

 

장소: 제1과학관 31214  e+첨단강의실 

 

초록:

Hair cells of the vertebrate inner ear are the mechanotransducers which have been proposed to amplify weak signals by generating active forces. While amplification in the mammalian cochlea is widely believed to originate from the membrane dynamics involving outer hair cell motility, non-mammalian vertebrates lack outer hair cells. Nevertheless the ear of lower vertebrates achieves acute hearing. The exact mechanism is not yet clearly known. Hair bundle motility probably underlies the amplification process. Unlike mammalian hair cells, spontaneous oscillations have been observed in individual hair cells of turtles and frogs. However, in recent experiments under more natural conditions than previously studied, frog hair bundles with an overlying membrane are found not to spontaneously oscillate, but are in fact quiescent.

 Here we introduce our recent theory[1] on the auditory transduction of the bullfrog sacculus, where  the coupling of hair bundles can induce the cessation of the spontaneous oscillation and enhanced signal-to-noise ratio. Using numerical simulations of models of bullfrog sacculi, we investigate the mechanotransduction properties of inhomogeneous hair bundles with elastic coupling and mechanical loading. We show that when inhomogeneous hair bundles are coupled with sufficient strength, all the spontaneous oscillations are suddenly quenched. This phenomenon is called amplitude death – the cessation of oscillation due to the coupling of oscillators, which was first noted in the 19th century by Rayleigh, who found that adjacent organ pipes can suppress each other's sound. We find that there exists an optimal value of the mass of the overlying membrane which gives the maximum signal-to-noise ratio. The hair bundles in this optimal condition turn out to be in the region where amplitude death is seen, which indicates the hair bundles are likely to exploit amplitude death for signal transmission.

 

[1] Ahn K-H. 2013 Enhanced signal-to-noise ratios in frog hearing can be achieved through amplitude death.  J R Soc Interface 10: 20130525.

 

 

Figure 1: Schematic figure for elastically coupled hair bundles with mechanical loading. (a)~(f) The power spectra of mechanical displacement for various inter-bundle coupling strength k and the stimulus amplitude F when 6 Hz signal is applied.

번호 제목 날짜 조회 수
공지 <12/8(Thu.) 11:00am>노벨상 소개 강연 - 2016년 노벨 물리학상: 위상 응집 물리의 탄생 2016.11.28 1026947
226 <3/19> 고자기장 하에서 반도체 양자구조의 광전이 특성 2014.03.13 72137
225 <Dec. 7(Wed.) 4:30 PM>Mechanotransduction of cells in vitro(세포기능의 역학적 조절) 2016.11.30 72648
224 <11/24>생물계의 물리학적 연구: 단분자 생물물리학과 세포 역학 연구 2006.11.21 72916
223 THINKING PHYSICS 발표회 2009.03.16 73073
222 <11/30> Spinning Black Holes: key to Gamma-ray Bur... 2007.11.26 73209
221 <Sep.12(Wed.) 4:30 PM> Functional Nanomaterials for Energy Harvesting 2018.09.05 73256
220 2007학년도 2학기 콜로퀴움 안내 2007.08.23 73385
219 <11/14> 한방의료기기에서 나노소자의 활용 2008.11.11 73605
218 <10/5> 국제핵융합로 프로젝트 및 이와 관련된 초전도 연구 2007.10.01 73634
217 <3/28> Nanoscale Physics related to Resistance Switchings &Its Applications to Resistance RAM 2008.03.24 73775
216 <11/19(수)> 3D topological insulators with magnetic impurities 2014.11.13 73921
215 <12/12> 나노물리학과 컴퓨터 시뮬레이션 2008.12.08 74072
214 <Oct.30(Wed.)> 왼손과 오른손, 기본 입자와 끈 2019.10.24 74121
213 <11/16> 방사선과 그 이용 2007.11.16 74426
212 <3/23> 차세대 전자 소자용 산화물 반도체 박막의 개발 2007.03.20 74432
211 <10/26> 차세대 비휘발성 메모리 나노 소자 2007.10.11 74500
210 <10/16> 복잡계의 물리 2009.10.09 74565
209 <4/7> Structure and Dynamics of Complex Networks 2006.04.03 74652
208 2008학년도 1학기 물리세미나1 강의계획서 2008.03.18 75012
207 <5/15>강상관 전자계의 열전변환 응용 2009.05.08 75065