PZT-hydrogel integrated active non-Hermitian complementary acoustic metamaterials with real time modulations through feedback control circuits

PZT-水凝胶集成有源非厄米互补声学超材料，通过反馈控制电路进行实时调制

• 批准号: 2102129
• 负责人: Chengzhi Shi
• 金额: $ 40万
• 依托单位: Georgia Tech Research Corporation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-08-15 至 2024-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2102129&HistoricalAwards=false
• 关键词: PZT; hydrogel; integrated; active; non

This grant will support research that will generate new fundamental knowledge on the dynamic and acoustic properties of a PZT-hydrogel based active complementary acoustic metamaterial. Such acoustic metamaterials will enable high energy transmission at high frequency through sound barriers, including those with strong intrinsic loss like skull for brain imaging and brain-machine interface. Transcranial ultrasound (i.e. ultrasound transmission through skull) has many applications including noninvasive surgeries and drug delivery. However, current transcranial ultrasound techniques are all based on sound waves with relatively low frequency and poor spatial resolution, and the energy transmission through the lossy skull is low even for such low frequency sound waves. Brain imaging and brain-machine interfaces require better spatial resolution, which can be realzied by enabling transmission of high frequency ultrasound through skulls, which is not achievable with existing technologies. Active non-Hermitian complementary acoustic metamaterials (NHCMM) are promising compensation media to complement with the strong transmission loss through skull for high frequency acoustic waves. This project explores the acoustic and material properties of PZT-hydrogel composites integrated with feedback control circuits for the experimental realization of NHCMM that can compensate the high frequency ultrasound transmission loss through a real skull. This experimental realization will set the foundation for high resolution ultrasound brain imaging and brain-machine interface. This research will have broader impacts in science, defense, industry and general society by satisfying the critical need for high performance brain imaging and brain-machine interface. In addition, this research will promote the progress of fundamental acoustics, soft matter physics, and metamaterials. This multi-disciplinary research will broaden the participation of underrepresented groups in science and engineering and positively impact STEM education.The objective of this research is to design, fabricate, and experimentally characterize an active NHCMM by integrating PZT elements, hydrogel, and feedback control circuits that can be used to complement sound barriers, including those with strong intrinsic loss such as skull, to achieve optimal energy transmission for brain imaging and brain-machine interface. The NHCMM has effective density and bulk modulus with negative values of that of the barrier to suppress the strong impedance mismatch and material gain that balances the intrinsic loss in the barrier. The NHCMM will be realized by integrating piezoelectric elements and hydrogel with electrical circuit components. The integrated feedback control circuit will actively modulate the effective acoustic properties of the metamaterials to realize the desired parameters of NHCMM and compensate impedance mismatch and loss simultaneously. This fundamental research project will pave the road for the realization of noninvasive ultrasonic brain imaging, high intensity focused ultrasound treatments, brain stimulation, and brain-machine interface. To achieve the proposed objective, the two PIs will utilize their complemented expertise in acoustics, metamaterials, and soft matter to accomplish the following research tasks: 1) Identify the dynamic properties of different types of hydrogels in a wide ultrasonic frequency band; 2) Design and fabricate hydrogel-based active NHCMMs with feedback-circuit-controlled piezoelectric elements to realize any desired effective density and bulk modulus with acoustic gain; 3) Characterize and optimize NHCMMs to enhance acoustic energy transmission through lossy skull for brain imaging and brain-machine interface.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

这项资助将支持研究，这将产生新的基础知识的动态和声学特性的PZT-水凝胶为基础的主动互补声学超材料。这种声学超材料将使高能量在高频下通过声音屏障传输，包括那些具有强烈内在损失的材料，如用于脑成像和脑机接口的头骨。经颅超声（即通过颅骨的超声传输）具有许多应用，包括非侵入性手术和药物输送。然而，目前的经颅超声技术都是基于具有相对低频率和差的空间分辨率的声波，并且即使对于这样的低频声波，通过有损颅骨的能量传输也是低的。大脑成像和脑机接口需要更好的空间分辨率，这可以通过使高频超声通过头骨传输来实现，而这是现有技术无法实现的。有源非厄米互补声学超材料（NHCMM）是一种很有前途的补偿介质，可以弥补高频声波在颅骨中的强传输损耗。该项目探讨了PZT-水凝胶复合材料的声学和材料特性，该复合材料与反馈控制电路集成，用于NHCMM的实验实现，该NHCMM可以通过真实的颅骨补偿高频超声传输损耗。这一实验实现将为高分辨率超声脑成像和脑机接口奠定基础。这项研究将通过满足高性能脑成像和脑机接口的迫切需求，在科学，国防，工业和一般社会产生更广泛的影响。此外，这项研究将促进基础声学、软物质物理和超材料的发展。这项多学科的研究将扩大在科学和工程中代表性不足的群体的参与，并积极影响STEM教育。这项研究的目的是设计，制造和实验表征一个积极的NHCMM，通过集成PZT元件，水凝胶，和反馈控制电路，可用于补充声屏障，包括那些有很强的内在损失，如头骨，以实现脑成像和脑机接口的最佳能量传输。NHCMM具有势垒的负值的有效密度和体积模量，以抑制强阻抗失配和平衡势垒中的固有损耗的材料增益。NHCMM将通过将压电元件和水凝胶与电路元件集成来实现。集成的反馈控制电路将主动调制超材料的有效声学特性，以实现NHCMM的期望参数，并同时补偿阻抗失配和损耗。该基础研究项目将为实现无创超声脑成像、高强度聚焦超声治疗、脑刺激和脑机接口铺平道路。为达致上述目的，两名研究员将利用他们在声学、超材料及软物质方面的互补专长，完成以下研究工作：1）在较宽的超声波频带内，识别不同类型水凝胶的动态特性; 2）设计并制备了具有反馈电路的水凝胶基有源NHC-MEMS器件。控制压电元件以实现具有声学增益的任何期望的有效密度和体积模量; 3）表征和优化NHC 01以增强通过有损耗颅骨的声能传输，用于脑成像和脑-该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Inverse design of acoustic metasurfaces using space-filling points

• DOI: 10.1063/5.0096869
• 发表时间: 2022-08
• 期刊: Applied Physics Letters
• 影响因子: 4
• 作者: A. Krishna;Steven R. Craig;Chengzhi Shi;V. R. Joseph