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1. A Continuous Articulatory Gesture Based Liveness Detection for Voice Authentication on Smart Devices

   https://doi.org/10.1109/JIOT.2022.3199995  

   Zhang, Linghan ; Tan, Sheng ; Chen, Yingying ; Yang, Jie ( August 2022 , IEEE Internet of Things Journal)

   Voice biometrics is drawing increasing attention to user authentication on smart devices. However, voice biometrics is vulnerable to replay attacks, where adversaries try to spoof voice authentication systems using pre-recorded voice samples collected from genuine users. To this end, we propose VoiceGesture, a liveness detection solution for voice authentication on smart devices such as smartphones and smart speakers. With audio hardware advances on smart devices, VoiceGesture leverages built-in speaker and microphone pairs on smart devices as Doppler Radar to sense articulatory gestures for liveness detection during voice authentication. The experiments with 21 participants and different smart devices show that VoiceGesture achieves over 99% and around 98% detection accuracy for text-dependent and text-independent liveness detection, respectively. Moreover, VoiceGesture is robust to different device placements, low audio sampling frequency, and supports medium range liveness detection on smart speakers in various use scenarios, including smart homes and smart vehicles. 

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2. First‐principles modeling for optimal design, operation, and integration of energy conversion and storage systems

   https://doi.org/10.1002/aic.16482  

   Smolin, Yuriy Y. ; Lau, Kenneth K. S. ; Soroush, Masoud ( December 2018 , AIChE Journal)

   Energy and electricity consumption is expected to increase in the foreseeable future. Concurrently, sustainability concerns of fossil‐based energy resources have motivated the use of renewable and reusable energy resources, and the use of more efficient energy‐converting and energy‐consuming systems. Consequently, for the past decade, there have been major theoretical and experimental advances in (1) energy generation from renewable and reusable resources and (2) energy‐consuming and energy‐converting devices. This review article focuses on the recent theoretical advances in renewable energy conversion devices such as photovoltaic and fuel cells, and in energy storage devices such as rechargeable batteries, flow batteries, and supercapacitors. Due to similar chemistry, electrochemistry, and physics of these systems, modeling similarities between different energy systems are highlighted. This review puts into perspective how first‐principles mathematical modeling has contributed to systematic advances in the optimal design, operation, and integration of these systems. © 2018 American Institute of Chemical EngineersAIChE J, 65: e16482 2019

    

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3. Effect of Perforation on the Thermal and Electrical Breakdown of Self‐Rolled‐Up Nanomembrane Structures

   https://doi.org/10.1002/admi.201901022  

   Michaels, Julian A. ; Wood, Derek R. ; Froeter, Paul J. ; Huang, Wen ; Sievers, Dane J. ; Li, Xiuling ( September 2019 , Advanced Materials Interfaces)

   Strain‐induced self‐rolled‐up membranes (S‐RuM) are structures formed spontaneously by releasing a strained layer or layer stacks from its mechanical support, with unique applications in passive photonics, electronics, and bioengineering. Depending on the thermal properties of the strained layers, these structures can experience various thermally induced deformations. These deformations can be avoided and augmented with the addition of strategically placed perforations in the membrane. This study reports on the use of perforations to modify the thermal effects on strained silicon nitride S‐RuM structures. A programmable fuse with well‐defined thermal threshold, ultrasmall footprint, and 2–3 V voltage rating is demonstrated, which can potentially serve as an on‐chip sensing device for power electronic circuits.

    

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4. Strain engineering photonic properties in monolayer semiconductors through mechanically-reconfigurable wrinkling

   https://doi.org/10.1117/12.2567539  

   Hossein, Mohammad A. ; Zhang, Yue ; van der Zande, Arend ( August 2020 , Proc. of SPIE Physical Chemistry of Semiconductor Materials and Interfaces IX)

   Congreve, Daniel ; Nielsen, Christian ; Musser, Andrew J. (Ed.)

   Inhomogeneous and three-dimensional strain engineering in two dimensional materials opens up new avenues to straintronic devices for control strain sensitive photonic properties. Here we present a method to tune strain by wrinkling monolayer WSe2 attached to a 15 nm thick ALD support layer and compressing the heterostructure on a soft substrate. The ALD film stiffens the 2D material, enabling optically resolvable micron scale wrinkling rather than nanometer scale crumpling and folding. Using photoluminescence spectroscopy, we show the wrinkling introduces periodic modulation of the bandgap by 47 meV, corresponding with strain modulation from +0.67% tensile strain at the wrinkle crest to -0.31% compressive strain at the trough. Moreover, we show that cycling the substrate strain mechanically reconfigures the magnitude and direction of wrinkling and resulting band tuning. These results pave the way towards stretchable multifuctional devices based on strained 2D materials. 

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5. Recent progress in electrospun nanomaterials for wearables

   https://doi.org/10.1063/5.0088136  

   Das, Riddha ; Zeng, Wenxin ; Asci, Cihan ; Del-Rio-Ruiz, Ruben ; Sonkusale, Sameer ( June 2022 , APL Bioengineering)

   Wearables have garnered significant attention in recent years not only as consumer electronics for entertainment, communications, and commerce but also for real-time continuous health monitoring. This has been spurred by advances in flexible sensors, transistors, energy storage, and harvesting devices to replace the traditional, bulky, and rigid electronic devices. However, engineering smart wearables that can seamlessly integrate with the human body is a daunting task. Some of the key material attributes that are challenging to meet are skin conformability, breathability, and biocompatibility while providing tunability of its mechanical, electrical, and chemical properties. Electrospinning has emerged as a versatile platform that can potentially address these challenges by fabricating nanofibers with tunable properties from a polymer base. In this article, we review advances in wearable electronic devices and systems that are developed using electrospinning. We cover various applications in multiple fields including healthcare, biomedicine, and energy. We review the ability to tune the electrical, physiochemical, and mechanical properties of the nanofibers underlying these applications and illustrate strategies that enable integration of these nanofibers with human skin. 

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