基于螺旋形超材料的宽带心肺音听诊器件  

A helical metamaterial-based auscultation device for broadband cardiopulmonary sound detection

作　　者：陈政吉 刘京京 梁彬[1] 杨京[1] 程建春[1] Zhengji Chen;Jingjing Liu;Bin Liang;Jing Yang;Jianchun Cheng(Department of Physics,Nanjing University,Key Laboratory of Modern Acoustics of Ministry of Education,Collaborative Innovation Center of Advanced Microstructures,Nanjing 210093,China)

机构地区：[1]南京大学物理学院,近代声学教育部重点实验室,人工微结构科学与技术协同创新中心,南京210093

出　　处：《科学通报》2023年第26期3472-3481,共10页Chinese Science Bulletin

基　　金：国家重点研发计划(2022YFA1404402,2017YFA0303700);国家自然科学基金(11634006,12174190)资助。

摘　　要：圆柱管听诊器具有结构简单、价格低廉、适用范围广等优势,但其尺寸通常较大,且工作频带难以覆盖心肺音频率范围.本文基于螺旋形超材料提出了一种圆柱形的心肺音听诊器件的设计理论,其尺寸可满足便携性要求(长度约1/5波长),且工作频带能有效覆盖典型心肺音频率范围(20∼1000 Hz).所设计器件的基本工作原理是利用内置的螺旋形超材料增加声波的传播路径长度,使不同频率下的等效声折射率均得到显著提升,从而在有效缩减结构尺寸的同时保持极宽的工作频带.基于等效媒质理论,对该结构中的声传播过程进行了理论分析,研究了其等效声学参数及灵敏度增益在不同频率下的变化特性,并通过有限元方法进行了验证.理论和仿真结果能够很好吻合,证明所设计的心肺音听诊器在20∼1000 Hz的宽频带内产生了平均10 dB的灵敏度提升.基于此,进一步分析了热黏滞损耗和结构参数变化对该器件的灵敏度和工作带宽的影响规律.最后,制备了心肺音听诊器样品并对其声学性能进行了实验测量,结果表明心肺音听诊器相比于圆柱管听诊器在20~1000 Hz全频带具有更高的灵敏度,在330~820 Hz频段的平均增益能够达到10 dB.本研究所设计的心肺音听诊器件具有灵敏度高、工作带宽大、设计简单、结构强度高、材质选择自由、鲁棒性等特性,为心肺音听诊器件的设计提供了新的思路,在医学临床诊断和声学传感等领域具有广泛的应用前景.The use of conventional stethoscopes in crucial situations when caring for patients with infectious disorders like COVID-19 and H1N1 is significantly limited by protective garments for infection protection.In order to solve this issue,a straight cylindrical stethoscope design is proposed that uses an empty potato chip canister coated in sterile paper and is inexpensive,safe,and practical to use.The design can be used as a significant substitute for conventional stethoscopes for clinical diagnosis in unique circumstances.By adjusting the diameter and length of the tube,the cylindrical tube stethoscope’s structural design gets further optimization which improves the effect of heart sound acquisition and raises the sound pressure level of cardiac auscultation by about 3 dB in comparison to the original structure.However,the dimension of the cylindrical stethoscope is often quite large,it might be challenging to design the structural elements so that the resonance frequency falls within the heart sound frequency range.The development of acoustic metamaterials,a class of composite materials with artificial microstructures,offers anomalous acoustic features not found in nature,considerably expanding the modulation possibilities for sound waves.The width of the effective operating frequency band is still constrained,despite the fact that the use of acoustic metamaterials can greatly reduce the size of cylindrical auscultation devices and enhance the auscultation effect of heart sounds.Normal lung sounds fall within the frequency range of 100–1000 Hz,as opposed to the typical heart sound range of 20–200 Hz.Hence,it is highly beneficial for research to efficiently expand the cylindrical auscultation device’s operational frequency band to the typical frequency range of heart and lung sounds while keeping the device’s compactness.In this study,a novel design theory for a cardiopulmonary auscultation device with sub-wavelength size(less than 1/5λ0,whereλ0 is the wavelength of the frequency band’s core frequency

关 键 词：螺旋形超材料 宽带传感 心肺音听诊 高灵敏度 

分 类 号：TH77[机械工程—仪器科学与技术]