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Wafer-Scale Ag₂S-Based Memristive Crossbar Arrays with Ultra-Low Switching-Energies Reaching Biological Synapses

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NANO-MICRO LETTERS 2025年第1期17卷 1-12页

作者： Zhu, Yuan Nyberg, Tomas Nyholm, Leif Primetzhofer, Daniel Shi, Xun Zhang, Zhen Uppsala Univ Dept Elect Engn Div Solid State Elect S-75121 Uppsala Sweden Uppsala Univ Dept Chem Uppsala Sweden Uppsala Univ Dept Phys & Astron Uppsala Sweden Chinese Acad Sci Shanghai Inst Ceram State Key Lab High Performance Ceram & Superfine M Shanghai 200050 Peoples R China

Memristive crossbar arrays (MCAs) offer parallel data storage and processing for energy-efficient neuromorphic computing. However, most wafer-scale MCAs that are compatible with complementary metal-oxide-semiconductor (CMOS) technology still suffer from substantially larger energy consumption than biological synapses, due to the slow kinetics of forming conductive paths inside the memristive units. Here we report wafer-scale Ag2S-based MCAs realized using CMOS-compatible processes at temperatures below 160 degrees C. Ag2S electrolytes supply highly mobile Ag+ ions, and provide the Ag/Ag2S interface with low silver nucleation barrier to form silver filaments at low energy costs. By further enhancing Ag+ migration in Ag2S electrolytes via microstructure modulation, the integrated memristors exhibit a record low threshold of approximately - 0.1 V, and demonstrate ultra-low switching-energies reaching femtojoule values as observed in biological synapses. The low-temperature process also enables MCA integration on polyimide substrates for applications in flexible electronics. Moreover, the intrinsic nonidealities of the memristive units for deep learning can be compensated by employing an advanced training algorithm. An impressive accuracy of 92.6% in image recognition simulations is demonstrated with the MCAs after the compensation. The demonstrated MCAs provide a promising device option for neuromorphic computing with ultra-high energy-efficiency.

关键词： Wafer-scale Ag2S films Reactive sputter Silver nucleation Ag+ migration Energy-efficient neuromorphic computing

3D tomographic analysis of equatorial plasma bubble using GNSS-TEC data from Indonesian GNSS Network

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Earth and Planetary Physics 2025年第1期9卷 127-136页

作者： Ihsan Naufal Muafiry Prayitno Abadi Teguh N.Pratama Dyah R.Martiningrum Sri Ekawati Yuandhika GWismaya Febrylian FChabibi Gatot HPramono Research Center for Climate and Atmosphere Indonesian National Research and Innovation Agency(BRIN)BandungIndonesia Indonesian Geospatial Information Agency(BIG) JakartaIndonesia dept.of Physics Faculty of ScienceUniversiti Teknologi MalaysiaJohor BahruMalaysia dept.Earth Planet Sci. Hokkaido UniversitySapporoJapan School of Electrical Engineering Telkom UniversityBandungIndonesia

Equatorial Plasma Bubbles(EPBs)are ionospheric irregularities that take place near the magnetic *** most commonly occur after sunset during the equinox months,although they can also be observed during other *** phenomenon significantly disrupts radio wave signals essential to communication and navigation *** national network of Global Navigation Satellite System(GNSS)receivers in Indonesia(>30°longitudinal range)provides an opportunity for detailed EPB *** explore this,we conducted preliminary 3D tomography of total electron content(TEC)data captured by GNSS receivers following a geomagnetic storm on December 3,2023,when at least four EPB clusters occurred in the Southeast Asian *** and extracted TEC depletion with a 120-minute running average were then used as inputs for a 3D tomography *** 2D spatial distribution consistently captured the four EPB clusters over *** tomography results were validated through a classical checkerboard test and comparisons with other ionospheric data sources,such as the Global Ionospheric Map(GIM)and International Reference Ionosphere(IRI)*** of the results demonstrates the capability of the Indonesian GNSS network to measure peak ionospheric *** findings highlight the potential for future three-dimensional research of plasma bubbles in low-latitude regions using existing GNSS networks,with extensive longitudinal coverage.

关键词： EPB Indonesian GNSS Network 3D tomography

Wafer-Scale Vertical 1D GaN Nanorods/2D MoS₂/PEDOT:PSS for Piezophototronic Effect-Enhanced Self-Powered Flexible Photodetectors

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NANO-MICRO LETTERS 2025年第1期17卷 1-15页

作者： Tang, Xin Jiang, Hongsheng Lin, Zhengliang Wang, Xuan Wang, Wenliang Li, Guoqiang South China Univ Technol State Key Lab Luminescent Mat & Devices Guangzhou 510640 Peoples R China South China Univ Technol Sch Mat Sci & Engn Dept Elect Mat Guangzhou 510640 Peoples R China

Vertical 1D GaN nanorod arrays/2D MoS2/PEDOT:PSS heterostructures in wafer scale have been fabricated for flexible photodetection ***-powered flexible photodetector at compressive strain reveals a significantly enhanced photoresponse with a responsivity of 2.47 A W-1 and response times of 40/45 mu s, which are superior to the state-of-the-art flexible *** work not only provides a valuable strategy for the design and construction of tunable van der Waals heterostructures, but also opens a new opportunity for flexible sensors. van der Waals (vdW) heterostructures constructed by low-dimensional (0D, 1D, and 2D) materials are emerging as one of the most appealing systems in next-generation flexible photodetection. Currently, hand-stacked vdW-type photodetectors are not compatible with large-area-array fabrication and show unimpressive performance in self-powered mode. Herein, vertical 1D GaN nanorods arrays (NRAs)/2D MoS2/PEDOT:PSS in wafer scale have been proposed for self-powered flexible photodetectors arrays firstly. The as-integrated device without external bias under weak UV illumination exhibits a competitive responsivity of 1.47 A W-1 and a high detectivity of 1.2 x 1011 Jones, as well as a fast response speed of 54/71 mu s, thanks to the strong light absorption of GaN NRAs and the efficient photogenerated carrier separation in type-II heterojunction. Notably, the strain-tunable photodetection performances of device have been demonstrated. Impressively, the device at - 0.78% strain and zero bias reveals a significantly enhanced photoresponse with a responsivity of 2.47 A W-1, a detectivity of 2.6 x 1011 Jones, and response times of 40/45 mu s, which are superior to the state-of-the-art self-powered flexible photodetectors. This work presents a valuable avenue to prepare tunable vdWs heterostructures for self-powered flexible photodetection, which performs well in flexible sensors.

关键词： Vertical nanorod arrays van der Waals heterostructure Piezophototronic effect Self-powered photodetection Flexible sensors

Slip-model Performance for Underexpanded Micro-scale Rocket Nozzle Flows

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Journal of Thermal Science 2007年第3期16卷 223-230页

作者： JoséA.Morí■igo JoséHermidaQuesada Francisco Caballero Requena dept.of Space Programmes dept.of

In aerospace Micro-Electro Mechanical Systems （MEMS）, the characteristic length scale of the flow approaches the molecular mean free path, thus invalidating the continuum description and enforcing the use of particle methods, like the Direct Simulation Monte Carlo （DSMC）, to deal with the non-equilibrium regions. Within the slip-regime （0.01〈Kn〈-0.1） both approaches, continuum and particle-based, seem to behave well in terms of accuracy. The present study summarizes the implementation and results obtained with a 2nO-order slip boundary condition in a Navier-Stokes solver to address the rarefaction near the nozzle walls. Its assessment and application to a cold-gas micro-scale conical nozzle of 300μm throat diameter, discharging into the low-pressure freestream, constitutes the major aim of the work. The slip-model incorporates the velocity slip with thermal creep and temperature jump, thus permitting to deal with non-isothermal flows as well. Results show that the gas experiences an intense rarefaction in the lip vicinity, pointing to the limits of model validity. Furthermore, a strong Mach deceleration is observed, attributed to the rather thick subsonic boundary layer and supersonic bulk heating caused by the viscous dissipation, in contrast with the expansion to occur in large rocket nozzles during underexpanded operation.

关键词： Slip flow MEMS micronozzles

Recent Advances in Artificial Sensory Neurons: Biological Fundamentals, Devices, Applications, and Challenges

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NANO-MICRO LETTERS 2025年第1期17卷 1-49页

作者： Zhong, Shuai Su, Lirou Xu, Mingkun Loke, Desmond Yu, Bin Zhang, Yishu Zhao, Rong Guangdong Inst Intelligence Sci & Technol Zhuhai 519031 Hengqin Peoples R China Zhejiang Univ Coll Integrated Circuits Hangzhou 3112000 Peoples R China ZJU Hangzhou Global Sci & Technol Innovat Ctr Hangzhou 310027 Peoples R China Singapore Univ Technol & Design Dept Sci Math & Technol Singapore 487372 Singapore Tsinghua Univ Dept Precis Instruments Beijing 100084 Peoples R China Tsinghua Univ Ctr Brain Inspired Comp Res Beijing 100084 Peoples R China Tsinghua Univ IDG McGovern Inst Brain Res Beijing 100084 Peoples R China

Biological fundamentals and recent progress of artificial sensory neurons are systematically *** device, performance metrics, and potential applications of artificial sensory neurons are *** for the future development of artificial sensory neurons are discussed. Spike-based neural networks, which use spikes or action potentials to represent information, have gained a lot of attention because of their high energy efficiency and low power consumption. To fully leverage its advantages, converting the external analog signals to spikes is an essential prerequisite. Conventional approaches including analog-to-digital converters or ring oscillators, and sensors suffer from high power and area costs. Recent efforts are devoted to constructing artificial sensory neurons based on emerging devices inspired by the biological sensory system. They can simultaneously perform sensing and spike conversion, overcoming the deficiencies of traditional sensory systems. This review summarizes and benchmarks the recent progress of artificial sensory neurons. It starts with the presentation of various mechanisms of biological signal transduction, followed by the systematic introduction of the emerging devices employed for artificial sensory neurons. Furthermore, the implementations with different perceptual capabilities are briefly outlined and the key metrics and potential applications are also provided. Finally, we highlight the challenges and perspectives for the future development of artificial sensory neurons.

关键词： Artificial intelligence Emerging devices Artificial sensory neurons Spiking neural networks Neuromorphic sensing

Flexible Strain Sensors with Ultra-High Sensitivity and Wide Range Enabled by Crack-Modulated Electrical Pathways

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NANO-MICRO LETTERS 2025年第1期17卷 1-19页

作者： Bai, Yunzhao Zhou, Yunlei Wu, Xuanyu Yin, Mengfei Yin, Liting Qu, Shiyuan Zhang, Fan Li, Kan Huang, Yongan Huazhong Univ Sci & Technol State Key Lab Intelligent Mfg Equipment & Technol Wuhan 430074 Peoples R China Huazhong Univ Sci & Technol Flexible Elect Res Ctr Wuhan 430074 Peoples R China Xidian Univ Hangzhou Inst Technol Hangzhou 311200 Peoples R China Xidian Univ Sch Mechanoelect Engn Xian 710071 Peoples R China Univ Southern Calif Dept Aerosp & Mech Engn Los Angeles CA 90089 USA

This study presents a breakthrough in flexible strain sensor technology with the development of an ultra-high sensitivity and wide-range sensor, addressing the critical challenge of reconciling sensitivity with measurement range. Inspired by the structure of bamboo slips, we introduce a novel approach that utilises liquid metal to modulate the electrical pathways within a cracked platinum fabric electrode. The resulting sensor demonstrates a gauge factor greater than 108 and a strain measurement capability exceeding 100%. The integration of patterned liquid metal enables customisable tuning of the sensor's response, while the porous fabric structure ensures superior comfort and air permeability for the wearer. Our design not only optimises the sensor's performance but also enhances the electrical stability that is essential for practical applications. Through systematic investigation, we reveal the intrinsic mechanisms governing the sensor's response, offering valuable insights for the design of wearable strain sensors. The sensor's exceptional performance across a spectrum of applications, from micro-strain to large-strain detection, highlights its potential for a wide range of real-world uses, demonstrating a significant advancement in the field of flexible electronics.

关键词： Flexible strain sensor Fabric Crack Response regulation Epidermal device

Analytical solutions of uniform extended dislocations and tractions over a circular area in anisotropic magnetoelectroelastic bimaterials

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Acta Mechanica Sinica 2013年第1期29卷 73-84页

作者： Y.-F. Zhao X.-C. Shang E. Pan dept. of Civil Engineering University of Akron dept. of Applied Mechanics University of Science and Technology

In this paper, we derive the analytical solutions in a three-dimensional anisotropic magnetoelectroelastic bimaterial space subject to uniform extended dislocations and tractions within a horizontal circular area. By virtue of the Stroh formalism and Fourier transformation, the final expression of solutions in the physical domain contains only line integrals over [0, 2π] rather than infinite integrals. As the reduced cases, the half-space and homogeneous full-space solutions can be directly derived from the present solutions. Also, in terms of material domains, the present solutions can be reduced to the piezoelectric, piezomagnetic, purely elastic materials with different symmetries of material prop- erty. To carry out numerical calculations, Gauss quadrature is adopted. In the numerical examples, the effect of different loading locations on the response at the interface is analyzed. It is shown that, when the magnetic traction or electric dislocation is applied, the physical quantities on the interface may not decrease monotonically as the loading area moves away from the interface. The distributions of different in-plane physical quantities on the upper and lower interfaces under various extended horizontal loadings are compared and the differences are discussed. The work presented in this paper can serve as benchmarks for future numerical studies in related research fields.

关键词： Anisotropic bimaterial space. Magnetoelectroe- lastic Extended dislocations Extended tractions Circular loading Analytic solutions

Seismic risk assessment for developing countries: Pakistan as a case study

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Earthquake Engineering and Engineering Vibration 2018年第4期17卷 787-804页

作者： Shaukat A.Khan Kypros Pilakoutas Iman Hajirasouliha Reyes Garcia Maurizio Guadagnini dept. of Civil Engineering Abasyn University dept. of Civil and Structural Engineering The University of Sheffield

Modern Earthquake Risk Assessment（ERA） methods usually require seismo-tectonic information for Probabilistic Seismic Hazard Assessment（PSHA） that may not be readily available in developing countries. To bypass this drawback, this paper presents a practical event-based PSHA method that uses instrumental seismicity, available historical seismicity, as well as limited information on geology and tectonic setting. Historical seismicity is integrated with instrumental seismicity to determine the long-term hazard. The tectonic setting is included by assigning seismic source zones associated with known major faults. Monte Carlo simulations are used to generate earthquake catalogues with randomized key hazard parameters. A case study region in Pakistan is selected to demonstrate the effectiveness of the method. The results indicate that the proposed method produces seismic hazard maps consistent with previous studies, thus being suitable for generating such maps in regions where limited data are available. The PSHA procedure is developed as an integral part of an ERA framework named EQRAM. The framework is also used to determine seismic risk in terms of annual losses for the study region.

关键词： recycled concrete frame-shear wall concealed bracings shaking table test nonlinear time-history responseanalysis

Dynamic Fractal Transform with Applications to Image Data Compression

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Journal of Computer Science & Technology 1997年第3期12卷 202-209页

作者：王舟余英林 dept.ofElectronicandCommunicationEngineering SouthChinaUniv.ofTechnologyGuangzhou510641 dept.ofElectr

A recent trend in computer graphics and image processing is to use Iterated Function System (IFS) to generate and describe both man-made graphics and natural images. Jacquin was the first to propose a fully automatic gray scale image compression algorithm which is referred to as a typical static fractal transform based algorithm in this paper. By using this algorithm, an image can be condensely described as a fractal transform operator which is the combination of a set of fractal mappings. When the fractal transform operator is iteratedly applied to any initial image, a unique attractor (reconstructed image) can be achieved. In this paper) a dynamic fractal transform is presented which is a modification of the static transform. Instead of being fixed, the dynamic transform operator varies in each decoder iteration, thus differs from static transform operators. The new transform has advantages in improving coding efficiency and shows better convergence for the decoder.

关键词： Fractals Iterated Function System (IFS) data compression,image processing