Khaleghi Morteza, Cheng Jeffrey Tao, Furlong Cosme, Rosowski John J
Center for Holographic Studies and Laser micro-mechaTronics (CHSLT), Mechanical Engineering Department, Worcester Polytechnic Institute, 100 Institute Road, Worcester, Massachusetts 01609, USA.
Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Department of Otology and Laryngology, Harvard Medical School, 243 Charles Street, Boston, Massachusetts 02114, USA.
J Acoust Soc Am. 2016 Jan;139(1):104-17. doi: 10.1121/1.4935386.
Computer-controlled digital holographic techniques are developed and used to measure shape and four-dimensional nano-scale displacements of the surface of the tympanic membrane (TM) in cadaveric human ears in response to tonal sounds. The combination of these measurements (shape and sound-induced motions) allows the calculation of the out-of-plane (perpendicular to the surface) and in-plane (tangential) motion components at over 1,000,000 points on the TM surface with a high-degree of accuracy and sensitivity. A general conclusion is that the in-plane motion components are 10-20 dB smaller than the out-of-plane motions. These conditions are most often compromised with higher-frequency sound stimuli where the overall displacements are smaller, or the spatial density of holographic fringes is higher, both of which increase the uncertainty of the measurements. The results are consistent with the TM acting as a Kirchhoff-Love's thin shell dominated by out-of-plane motion with little in-plane motion, at least with stimulus frequencies up to 8 kHz.
开发了计算机控制的数字全息技术，并用于测量尸体人耳中鼓膜（TM）表面响应音调声音的形状和四维纳米级位移。这些测量结果（形状和声音引起的运动）相结合，能够高精度、高灵敏度地计算出TM表面超过1,000,000个点处的平面外（垂直于表面）和平行于平面（切向）运动分量。一个普遍的结论是，平面内运动分量比平面外运动小10-20dB。在高频声音刺激下，这些条件最常受到影响，因为此时整体位移较小，或者全息条纹的空间密度较高，这两者都会增加测量的不确定性。结果表明，至少在高达8kHz的刺激频率下，TM的行为类似于基尔霍夫-洛夫薄壳，以平面外运动为主，平面内运动很少。
