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 1078429
349 <May.30(Wed.) 4:30 PM> 구리산화물 고온 초전도체의 특성과 응용 2018.05.23 45423
348 <Dec.6(Wed.) 4:30 PM> 실험핵천체물리학: 과거와 미래(Experimental Nuclear Astrophysics: Past and Future) 2017.11.29 45578
347 <Nov.21(Wed.) 4:30 PM> 핵물리학과 RAON 2018.11.15 45661
346 <Mar.7(Wed.) 4:30 PM>Acoustic metamaterial: principles and applications of phononic crystals 2018.03.02 46048
345 <May.23(Wed.) 4:30 PM> 한국 희귀동위원소과학 프로젝트(Rare Isotope Science Project in Korea) 2018.05.16 46284
344 <Nov.29(Wed.) 4:30 PM> The Intensity Frontier Experiment & SHiP 2017.11.22 46324
343 <Nov. 1(Wed.) 4:30 PM> 광자와 이온트랩을 이용한 양자 정보처리 2017.10.25 46358
342 <Mar.21(Wed.) 4:30 PM>깊은 땅속 중성미자 실험, DUNE 2018.03.14 46503
341 2022학년도 1학기 콜로퀴움 일정 2022.01.10 46576
340 <April.3(Wed.)> 전자구조계산을 이용한 새로운 양자물질 연구 2019.03.27 46752
339 <Sep. 6(Wed.) 4:30 PM> Particles in the Universe 2017.09.01 47033
338 <Sep. 20(Wed.) 4:30 PM> 양자이론에 대한 `서울해석` 시도하기 2017.09.13 47262
337 <Sep. 13(Wed.) 4:30 PM> 우주론 100년, 어디로 가고 있는가? 2017.09.06 47684
336 <April.10(Wed.)> 자성 반데르발스 물질 발견과 전망(Discovery and Perspective of magnetic van der Waals materials) 2019.04.04 48201
335 <April.11(Wed.) 4:30 PM>History of Superconductivity and its Future 2018.04.04 49548
334 <Mar.10(Wed.)> Dark matter searches in neutrino detectors 2021.03.04 50172
333 <Oct. 11(Wed.) 4:30 PM> Graphene Membrane for Imaging Molecular Assembly and Dynamics 2017.09.27 50761
332 <June 7(Wed.) 4:30 PM> 물리학으로 보는 인간과 사회 2017.05.31 51133
331 <April. 12 (Wed.) 4:30 PM>디랙물질을 통해서 본 강상관 계의 양자 홀로그래피적 조명: 2017.04.05 51227
330 <Dec.11(Wed.)>데이터 과학으로서의 물리학. 그리고 금융투자업 2019.12.04 51383