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Nonlinear dynamic response of bimorph piezoelectric energy harvester with functionally graded porous core

Noise and Vibration Worldwide 2023年第2-3期54卷 145-157页

作者： Akbar, Narges Soltani, Madjid Department of Mechanical Engineering Alzahra University Tehran Iran Department of Mechanical Engineering K. N. Toosi University of Technology Tehran Iran Department of Electrical and Computer Engineering University of Waterloo WaterlooON Canada University of Waterloo WaterlooON Canada Advanced Bioengineering Initiative Center Computational Medicine Center K. N. Toosi University of Technology Tehran Iran

This study deals with piezoelectric energy harvesters carrying the magnet at the free end while a magnifier connected them to the base. The harvester consists of a cantilever beam with Functionally Graded (FG) porous foam core and two piezoelectric faces while taking into account the von-Karman strains and the magnetic interaction of two magnets. The governing equation has been developed using Hamilton’s principle and reduced-order via the Galerkin method. Frequency response of vibrations and voltage derived using harmonic balance method and the adjusted model has been confirmed by parametric studies of the lumped parameter model. A parametric study is also performed to expose the effects of porosity coefficient and pattern, magnifier ratios, and excitation level on the responses. Results show that by correct selection of the magnifier parameters, the proposed harvester can provide a higher output over a wider frequency band. Also, the core porosity increases the flexibility of the beam and raised the voltage by a factor of 1.8. © The Author(s) 2023.

关键词： Porosity

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Subwavelength imaging using a solid‑immersion diffractive optical processor

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eLight 2024年第1期4卷 203-222页

作者： Jingtian Hu Kun Liao Niyazi Ulas Dinc Carlo Gigli Bijie Bai Tianyi Gan Xurong Li Hanlong Chen Xilin Yang Yuhang Li Cağatay Işıl Md Sadman Sakib Rahman Jingxi Li Xiaoyong Hu Mona Jarrahi Demetri Psaltis Aydogan Ozcan Electrical and Computer Engineering Department University of CaliforniaLos AngelesCA 90095USA Bioengineering Department University of CaliforniaLos AngelesCA 90095USA California NanoSystems Institute(CNSI) University of CaliforniaLos AngelesCA 90095USA Department of Physics Peking UniversityBeijing 100871China School of Engineering Ecole Polytechnique Federale de Lausanne(EPFL)LausanneSwitzerland David Geffen School of Medicine University of CaliforniaLos AngelesCA 90095USA

Phase imaging is widely used in biomedical imaging,sensing,and material characterization,among other ***,direct imaging of phase objects with subwavelength resolution remains a ***,we demonstrate subwavelength imaging of phase and amplitude objects based on all-optical diffractive encoding and *** resolve subwavelength features of an object,the diffractive imager uses a thin,high-index solid-immersion layer to transmit high-frequency information of the object to a spatially-optimized diffractive encoder,which converts/encodes high-frequency information of the input into low-frequency spatial modes for transmission through *** subsequent diffractive decoder layers(in air)are jointly designed with the encoder using deep-learning-based optimization,and communicate with the encoder layer to create magnified images of input objects at its output,revealing subwavelength features that would otherwise be washed away due to diffraction *** demonstrate that this all-optical collaboration between a diffractive solid-immersion encoder and the following decoder layers in air can resolve subwavelength phase and amplitude features of input objects in a highly compact *** experimentally demonstrate its proof-of-concept,we used terahertz radiation and developed a fabrication method for creating monolithic multi-layer diffractive *** these monolithically fabricated diffractive encoder-decoder pairs,we demonstrated phase-to-intensity(P→I)transformations and all-optically reconstructed subwavelength phase features of input objects(with linewidths of~λ/3.4,whereλis the illumination wavelength)by directly transforming them into magnified intensity features at the *** solid-immersion-based diffractive imager,with its compact and cost-effective design,can find wide-ranging applications in bioimaging,endoscopy,sensing and materials characterization.

关键词： Diffractive processors Solid immersion imaging Phase-to-intensity transformations

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Blood Flow Analysis of Subject-Specific Cerebral Arterial Tree: A Focus on the Redistribution of the Blood Flow After Occlusion 22

Blood Flow Analysis of Subject-Specific Cerebral Arterial Tr...

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22nd IEEE International Symposium on Biomedical Imaging, ISBI 2025

作者： Ghaffari, Amin Vahid, Mobina Amiri Zaree, Pedram Saadabadi, Kasra Mazarei Ghaffari, Mahsa University of California Department of Bioengineering Riverside United States Amirkabir University of Technology Department of Mechanical Engineering Tehran Iran University of California Department of Computer Science Riverside United States University of California Department of Electrical Engineering Riverside United States University of Illinois Department of Bioengineering Chicago United States

ISBN: (纸本)9798331520526

During vascular occlusions, the blood flow distribution in the cerebroarterial tree changes and can lead to insufficient blood flow, which can in turn cause tissue damage or ischemia. In such situations, predicting blood flow dynamics in a timely manner is crucial as it provides information about regions at risk, enabling clinicians to select optimal sites for revascularization procedures. This paper presents the development of a hemodynamic simulator designed to model pressure and flow, enabling detailed analysis of blood flow redistribution in response to arterial blockages. We focused on the role of Circle of Willis to provide immediate compensation for the loss of blood supply to the distal sites of occluded vessels. For this purpose, the angioarchitecture of a cerebral arterial tree was acquired using magnetic resonance angiography from a human subject with a complete Circle of Willis, and in-vivo blood flow measurements were used to obtain subject-specific boundary conditions. A 1D arterial network simulator was developed to predict the flow through the entire cerebral vascular tree model after five different scenarios of arteries occlusion. The blood flow in the communicating arteries, particularly in the right middle cerebral artery, significantly changed in different occlusion cases showing their importance for blood flow accommodation after occlusion. © 2025 IEEE.

关键词： Plasma (human)

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ADC-Less 3D-NAND Compute-in-Memory Architecture Using Margin Propagation 66

ADC-Less 3D-NAND Compute-in-Memory Architecture Using Margin...

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2023 IEEE 66th International Midwest Symposium on Circuits and Systems, MWSCAS 2023

作者： Undavalli, Aswin Chowdary Cauwenberghs, Gert Natarajan, Arun Chakrabartty, Shantanu Nagulu, Aravind Washington University in St. Louis Department of Electrical and Systems Engineering MO United States University of California at San Diego Department of Bioengineering CA United States School of Electrical Engineering and Computer Science Oregon State University CorvallisOR United States

ISBN: (纸本)9798350302103

Compute In Memory (CIM) has gained significant attention in recent years due to its potential to overcome the memory bottleneck in Von-Neumann computing architectures. While most CIM architectures use non-volatile memory elements in a NOR-based configuration, NAND-based configuration, and in particular, 3D-NAND flash memories are attractive because of their potential in achieving ultra-high memory density and ultra-low cost per bit storage. Unfortunately, the standard multiply-and-accumulate (MAC) CIM-paradigm can not be directly applied to NAND-flash memories. In this paper, we report a NAND-Flash-based CIM architecture by combining the conventional 3D-NAND flash with a Margin-Propagation (MP) based approximate computing technique. We show its application for implementing matrix-vector multipliers (MVMs) that do not require analog-to-digital converters (ADCs) for read-out. Using simulation results we show that this approach has the potential to provide a 100 x improvement in compute density, read speed, and computation efficiency compared to the current state-of-the-art. © 2023 IEEE.

关键词： Compute-In Memory Margin Propagation Matrix Vector Multipliers Multiply and Accumulate NAND Flash

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Crosstalk in polymer microelectrode arrays

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Nano Research 2021年第9期14卷 3240-3247页

作者： Yi Qiang Wen Gu Zehua Liu Shanchuan Liang Jae Hyeon Ryu Kyung Jin Seo Wentai Liu Hui Fang Department of Electrical and Computer Engineering Northeastern UniversityBostonMA 02115USA Department of Bioengineering University of CaliforniaLos AngelesLos AngelesCA 90095USA Department of Bioengineering Northeastern UniversityBostonMA 02115USA

Thin-film polymer microelectrcxje arrays(MEAs)facilitate the high-resolution neural recording with its superior mechanical ***,the densely packed electrodes and interconnects along with the ultra-thin polymeric encapsulation/substrate layers give rise to non-negligible crosstalk,which could result in severe interference in the neural signal *** to the lack of standardized characterization or modeling of crosstalk in neural electrode arrays,to date,crosstalk in polymer MEAs remains poorly *** this work,the crosstalk between two adjacent polymer microelectrodes is measured experimentally and modeled using equivalent ***,this study demonstrated a two-well measuring platform and systematically characterized the crosstalk in polymer microelectrodes with true isolation of the victim channel and precise control of its grounding condition.A simple,unified equation from detailed circuit modeling was proposed to calculate the crosstalk in different *** element analysis(FEA)analysis was conducted further to explore the crosstalk in more aggressively scaled polymer electrode *** addition to standardizing neural electrode array crosstalk characterization,this study not only reveals the dependence of the crosstalk in polymer MEAs on a variety of key device parameters but also provides general guidelines for the design of thin polymer MEAs for high-quality neural signal recording.

关键词： crosstalk effect flexible microelectrodes equivalent circuit modelling finite element analysis polymer

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Erratum to “Edge Selections in Bilinear Dynamic Networks”

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IEEE Transactions on Automatic Control 2024年第1期70卷 705-706页

作者： Arthur Castello B. de Oliveira Milad Siami Eduardo D. Sontag Department of Electrical and Computer Engineering Northeastern University Boston MA USA Department of Bioengineering Northeastern University Boston MA USA

Lemma 2 of “Edge Selections in Bilinear Dynamical Networks” (Oliveira et al., 2024) allows one to efficiently compute a lower bound for the optimal $\mathcal {H}_{2}$ -norm of a bilinear dynamical network following optimal edge selection, by showing convexity of a relaxed version of the problem. However, the proof presented is wrong in general, leaving the statement unproven. In this note, we discuss a case in which the presented result is guaranteed to hold and update our experimental results in light of this fact. Despite this problem with an auxiliary result in the article, notice that the main result in Theorem 1 remains correct, proving supermodularity of the $\mathcal {H}_{2}$ -norm under edge addition.

关键词： Symmetric matrices Simulation Optimization Noise

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Wavelength-multiplexed multiplane quantitative phase imaging using a diffractive optical processor 11

Wavelength-multiplexed multiplane quantitative phase imaging...

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Quantitative Phase Imaging XI 2025

作者： Shen, Che-Yung Li, Jingxi Gan, Tianyi Li, Yuhang Bai, Langxing Jarrahi, Mona Ozcan, Aydogan Electrical and Computer Engineering Department University of California Los AngelesCA90095 United States Bioengineering Department University of California Los AngelesCA90095 United States University of California Los AngelesCA90095 United States Department of Computer Science University of California Los AngelesCA90095 United States

ISBN: (纸本)9781510684065

We present deep learning-designed all-optical processors that can perform multiplane quantitative phase imaging (QPI). By leveraging diffractive processing and wavelength multiplexing, our approach allows the direct capture of quantitative phase distributions of input objects located at different axial planes using an intensity-only image sensor, eliminating the need for digital phase recovery algorithms. A proof-of-concept experiment validated the approach, showcasing successful imaging of distinct phase objects at different axial positions in the terahertz spectrum. By providing a faster, more efficient method for QPI, this technology can be applied to medical diagnosis, material science, and environmental monitoring, among other applications. © 2025 SPIE.

关键词： Phase imaging Biological imaging Image processing Biomedical optics Imaging devices Multiplexing Stereoscopy

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All-Optical Phase Conjugation Using a Diffractive Visual Processor

All-Optical Phase Conjugation Using a Diffractive Visual Pro...

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CLEO: Applications and Technology in CLEO 2024, CLEO: A and T 2024 - Part of Conference on Lasers and Electro-Optics

作者： Shen, Che-Yung Li, Jingxi Gan, Tianyi Jarrahi, Mona Ozcan, Aydogan Electrical and Computer Engineering Department University of California Los AngelesCA90095 United States Bioengineering Department University of California Los AngelesCA90095 United States University of California Los AngelesCA90095 United States

We present a diffractive visual processor that can approximate optical phase conjugation operation by linear optical processing without any digital computing or external power sources, which can be used for turbidity ... 详细信息

关键词： Optical phase conjugation

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Unidirectional image magnification and demagnification using pyramid diffractive optical networks

Unidirectional image magnification and demagnification using...

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2024 Conference on Lasers and Electro-Optics, CLEO 2024

作者： Bai, Bijie Yang, Xilin Gan, Tianyi Li, Jingxi Mengu, Deniz Jarrahi, Mona Ozcan, Aydogan Electrical and Computer Engineering Department University of California Los AngelesCA90095 United States Bioengineering Department University of California Los AngelesCA90095 United States University of California Los AngelesCA90095 United States

ISBN: (纸本)9781957171395

We introduce a pyramid-structured deep diffractive optical network (P-D2NN) design that performs unidirectional image magnification and demagnification using reduced degrees of freedom. Experimental validation at terahertz spectrum demonstrates the efficacy of this design strategy. CLEO 2024 © Optica Publishing Group 2024 © 2024 The Author(s)

关键词： Optical fibers

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All-Optical Phase Conjugation Using a Diffractive Visual Processor

All-Optical Phase Conjugation Using a Diffractive Visual Pro...

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2024 Conference on Lasers and Electro-Optics, CLEO 2024

ISBN: (纸本)9781957171395

关键词： Adaptive optics

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