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Accurate atomic scanning transmission electron microscopy analysis enabled by deep learning

Nano Research 2024年第4期17卷 2971-2980页

作者： Tianshu Chu Lei Zhou Bowei Zhang Fu-Zhen Xuan Shanghai Key Laboratory of Intelligent Sensing and Detection Technology East China University of Science and TechnologyShanghai 200237China School of Mechanical and Power Engineering East China University of Science and TechnologyShanghai 200237China Key Laboratory of Pressure Systems and Safety of Ministry of Education East China University of Science and TechnologyShanghai 200237China

Currently,the machine learning(ML)-based scanning transmission electron microscopy(STEM)analysis is limited in the simulative stage,its application in experimental STEM is needed but ***,we built up a universal model to analyze the vacancy defects and single atoms accurately and rapidly in experimental STEM images using a full convolution *** our model,the unavoidable interference factors of noise,aberration,and carbon contamination were fully considered during the training,which were difficult to be considered in the *** toward the simultaneous identification of various vacancy types and low-contrast single atoms in the low-quality STEM images,our model showed rapid process speed(45 images per second)and high accuracy(>95%).This work represents an improvement in experimental STEM image analysis by ML.

关键词： deep learning low-dimensional materials atomic defects single atoms

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Mode-locked fiber laser with an embedded Sagnac interference filter for strain sensing

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Optics and Laser technology 2025年 190卷

作者： Jiang, Chen Wang, Zhiqiang Wan, Ying Zhang, Sheng Yun, Ling Sun, Bing Mou, Chengbo Liu, Yunqi Zhang, Zuxing Nanjing University of Posts and Telecommunications 9 Wenyuan Road Nanjing210023 China Information Materials and Intelligent Sensing Laboratory of Anhui Province Anhui University 111 Jiu Long Road Hefei230601 China The School of Physics and Optoelectronic Engineering Nanjing University of Information Science & Technology 219 Ningliu Road Nanjing210044 China The Key Laboratory of Specialty Fiber Optics and Optical Access Networks Shanghai University Shanghai200444 China

We demonstrate a saturable absorber-based mode-locked fiber laser with an embedded Sagnac interference filter for strain sensing. By selecting an appropriate birefringent fiber length in the loop, the interferometer exhibits two dips within the wavelength ranges of the amplified spontaneous emission spectrum, functioning as a bandpass filter for wavelength selection. Mode-locked pulses at the central wavelength of the bandpass filter can self-start by increasing the pump power. The laser-based axial strain sensing system retains the high sensitivity of a Sagnac interferometer while overcoming demodulation challenges caused by peak tracking of the interferometer spectrum. Strain sensing was achieved by monitoring the optical spectrum and radio frequency (RF) spectrum of the mode-locked pulses. Within a strain variation range of 0–1045 μϵ, the wavelength shift sensitivity reached 21 pm/μϵ. As strain increased, cavity length expansion resulted in a fundamental frequency RF spectrum shift sensitivity of −0.767 Hz/μϵ. The proposed system provides multiple types of strain demodulation options, and its compact structure holds the potential for structural health monitoring of bridges, pipelines, aviation materials, etc. © 2025 Elsevier Ltd

关键词： Atomic emission spectroscopy

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Absence of superconductivity and density-wave transition in ambient-pressure tetragonal La4Ni3O10

arXiv

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arXiv 2025年

作者： Shi, Mengzhu Li, Yikang Wang, Yuxing Peng, Di Yang, Shaohua Li, Houpu Fan, Kaibao Jiang, Kun He, Junfeng Zeng, Qiaoshi Song, Dongsheng Ge, Binghui Xiang, Ziji Wang, Zhenyu Ying, Jianjun Wu, Tao Chen, Xianhui CAS Key Laboratory of Strongly-coupled Quantum Matter Physics Department of Physics University of Science and Technology of China Anhui Hefei230026 China Hefei National Laboratory for Physical Sciences at the Microscale University of Science and Technology of China Anhui Hefei230026 China Institute of Physics Chinese Academy of Sciences Beijing National Laboratory for Condensed Matter Physics Beijing100190 China Collaborative Innovation Center of Advanced Microstructures Nanjing University Nanjing210093 China Hefei National Laboratory University of Science and Technology of China Hefei230088 China Shanghai China Center for High Pressure Science and Technology Advanced Research Shanghai China Information Materials and Intelligent Sensing Laboratory of Anhui Province Anhui Key Laboratory of Magnetic Functional Materials and Devices Institutes of Physical Science and Information Technology Anhui University Hefei China

The recent discovery of superconductivity in La3Ni2O7 and La4Ni3O10 under high pressure stimulates intensive research interests. These nickelates crystallize in an orthogonal/monoclinic structure with tilted NiO6 octahedra at ambient pressure and enter a density-wave-like phase at low temperatures. The application of pressure suppresses the octahedral tilting and triggers a transition to tetragonal structure (I4/mmm), which is believed to be a key prerequisite for the emergence of superconducting state. Here, by developing a high oxidative environment growth technology, we report the first tetragonal nickelates La4Ni3O10 microcrystals without octahedral tilting at ambient pressure. In tetragonal La4Ni3O10, transport measurements find that both density-wave and superconducting transitions are absent up to 160 GPa, indicating a robust tetragonal metallic ground state. Density functional theory calculations reveal that the band structure of ambient-pressure tetragonal La4Ni3O10 involves more dz2 orbital contribution to the Fermi surface, compared to the monoclinic phase or the high-pressure superconducting tetragonal phase. The concurrent absence of density-wave state and high-pressure superconductivity in our ambient-pressure tetragonal crystals of La4Ni3O10 suggests an underlying correlation between these two orders. It suggests that the tetragonal structure is not necessary, while the density-wave state is crucial for the superconductivity in nickelates. Our findings impose important constraints on the mechanism of pressure-induced superconductivity in nickelates and sheds new light on exploring ambient pressure high-temperature Ni-based superconductors. © 2025, CC BY.

关键词： Nickel oxide

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Optimization of Narrow-magnet EMAT for Lamb Waves with Low Distortion 3

Optimization of Narrow-magnet EMAT for Lamb Waves with Low D...

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3rd International Symposium on Sensor technology and Control, ISSTC 2024

作者： Qu, Haifeng Hu, Zheng Liu, Lishuai Xiang, Yanxun East China University of Science and Technology Shanghai Key Laboratory of intelligent Sensing and Detection Technology Shanghai China East China University of Science and Technology Shanghai Institute of Aircraft Mechanics and Control Shanghai Key Laboratory of intelligent Sensing and Detection Technology Shanghai China

ISBN: (纸本)9798331541637

Compared to traditional electromagnetic acoustic transducer (EMAT), the narrow-magnet EMAT extends its meander conductors to the edges and outside of the magnet, hence a wider area of the magnetic field can be used to excite stronger ultrasound waves. Because of the magnetic field inhomogeneity, the classical half-wavelength spacing rule is not suitable for the coil used in the narrow-magnet EMAT. Otherwise, obvious waveform distortions will appear. In this work, the coil conductor spacing correction methodology proposed in previous works is testified for Lamb wave excitations, and a simpler wavelength-based adjustment approach is proposed, where waveforms of low distortions can be obtained. Both approaches are evaluated in simulation and practical experiments, where the Lamb wave amplitude enhancement brought by the coil conductor spacing correction method is more than 157.41%, and the improvement achieved by the proposed wavelength adjustment concept is above 179.34%. © 2024 IEEE.

关键词： Ultrasonic waves

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Compressed sensing for Full Matrix Capture Data Based on Optimal Reconstruction Algorithm 8

Compressed Sensing for Full Matrix Capture Data Based on Opt...

引用

8th International Conference on intelligent Computing and Signal Processing, ICSP 2023

作者： Zhao, Zhiyuan Teng, Da Liu, Lishuai Xiang, Yanxun East China University of Science and Technology Shanghai Key Laboratory of Intelligent Sensing and Detection Technology Shanghai China

ISBN: (纸本)9798350302455

Ultrasonic phased array total focusing method (TFM) attracts much interest because of high image resolution and large dynamic range. However, the data acquisition method relied on by TFM is full matrix capture (FMC), which generates huge data and brings great pressure. In this paper, the feasibility of compressed sensing (CS) in the reconstruction of ultrasonic FMC data is investigated. Firstly, four greedy algorithms are used to compress and reconstruct the ultrasonic signal, and the optimal algorithm is selected according to the reconstruction accuracy and the influence of sampling rate is considered. Secondly, the optimal algorithm is applied to the reconstruction of undersampled FMC data, and TFM is performed based on reconstructed FMC data. The simulation results demonstrate that excellent reconstruction can be obtained using measurement points less than the Nyquist sampling limitation required, the spatial resolution of TFM imaging of FMC data reconstructed with CS remained unchanged. Finally, experimental verification is carried out. Although the experimental results are not as ideal as the simulation results, FMC data can still be accurately recovered with a small number of measurements and the identification of defects by TFM is guaranteed. © 2023 IEEE.

关键词： Data acquisition

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The Short-spacing Interferometer Array for Global 21-cm Signal detection (SIGMA): Design of the Antennas and Layout

arXiv

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arXiv 2025年

作者： Zhao, Feiyu Guo, Quan Zheng, Qian Liang, Ruxi Zhang, Pengfei Wu, Yajun Gu, Junhua Yang, Zhao Yu, Yun Huang, Yan Liu, Tianyang Shanghai Astronomical Observatory Chinese Academy of Sciences 80 Nandan Road Shanghai200030 China University of Chinese Academy of Sciences No.1 Yanqihu East Road Beijing101408 China Key Laboratory of Radio Astronomy and Technology Chinese Academy of Sciences 20A Datun Road Beijing100101 China Xidian University National Key Laboratory of Radar Detection and Sensing No. 2 South Taibai Road Xi’an710071 China National Astronomical Observatories Chinese Academy of Sciences 20A Datun Road Beijing100101 China

Numerous experiments have been designed to investigate the Cosmic Dawn (CD) and Epoch of Reionization (EoR) by examining redshifted 21-cm emissions from neutral hydrogen. Detecting the global spectrum of redshifted 21-cm signals is typically achieved through single-antenna experiments. However, this global 21-cm signal is deeply embedded in foreground emissions, which are about four orders of magnitude stronger. Extracting this faint signal is a significant challenge, requiring highly precise instrumental calibration. Additionally, accurately modelling receiver noise in single-antenna experiments is inherently complex. An alternative approach using a short-spacing interferometer is expected to alleviate these difficulties because the noise in different receivers is uncorrelated and averages to zero upon cross-correlation. The Short-spacing Interferometer array for Global 21-cm Signal detection (SIGMA) is an upcoming experiment aimed at detecting the global CD/EoR signal using this approach. We describe the SIGMA system with a focus on optimal antenna design and layout, and propose a framework to address cross-talk between antennas in future calibrations. The SIGMA system is intended to serve as a prototype to gain a better understanding of the system’s instrumental effects and to optimize its performance further. Copyright © 2025, The Authors. All rights reserved.

关键词： Dark Matter

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Design of A Rayleigh wave EMAT by using Racetrack Coil and Periodic Permanent Magnets 2

Design of A Rayleigh wave EMAT by using Racetrack Coil and P...

引用

2nd International Symposium on Sensor technology and Control, ISSTC 2023

作者： Guo, Xinfeng Lin, Junjie Hu, Zheng Xiang, Yanxun East China University of Science and Technology Shanghai Key Laboratory of Intelligent Sensing and Detection Technology Shanghai China

ISBN: (纸本)9798350314465

Rayleigh waves are widely used for the detection and characterization of defects nearby the surface in the modern industries. Electromagnetic acoustic transducers (EMATs) have received extensive attention because of the lack of physical coupling. However, the main drawback of the inefficiency in generating and receiving ultrasonic waves restricts the extension and application of Rayleigh wave EMAT. This article proposes a type of Rayleigh wave electromagnetic acoustic transducer, which is consisted of a racetrack coil and a group of periodic permanent magnet array with a special configuration. The configuration of PPMs in the proposed EMAT is different from that in the common sheared-horizontal wave EMATs. The magnet units are magnetization along the width direction. The racetrack coil generates eddy current, and the periodic permanent magnet array provides bias static magnetic fields. The directions of generated Lorentz forces depend on the relative position between the magnet units and the conductors. The center frequency of the generated guided waves depends on the distance between the adjacent magnet units. In 2D FE simulations, different models were established, and the generation efficiencies for Rayleigh wave of vertical and horizontal Lorentz forces were compared. In the experiments, the guided wave EMAT, generating both horizontal and vertical Lorentz forces, was fabricated and used in the experiment system. The results prove the performance of the proposed EMAT for the effective generation Rayleigh waves. © 2023 IEEE.

关键词： Permanent magnets

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An Omnidirectional EMAT Employing Spiral Coil and Annular Magnets for Enhanced Generation of A0 Mode Lamb Wave 2

An Omnidirectional EMAT Employing Spiral Coil and Annular Ma...

引用

2nd International Symposium on Sensor technology and Control, ISSTC 2023

作者： Guo, Xinfeng Lin, Junjie Hu, Zheng Xiang, Yanxun East China University of Science and Technology Shanghai Key Laboratory of Intelligent Sensing and Detection Technology Shanghai China

ISBN: (纸本)9798350314465

As a typical noncontact ultrasonic testing method, electromagnetic ultrasonic guided wave testing has received extensive attention in recent years. However, the low energy efficiency and signal-to-noise ratio is especially obvious in omnidirectional electromagnetic acoustic transducers. To solve this problem for noncontact guided wave positioning detction, this article proposes an omnidirectional electromagnetic acoustic transducer (EMAT) for enhanced generation of A0 mode ultrasonic Lamb waves with pure mode in non-ferromagnetic plates. The proposed EMAT consists of a spiral coil and a group of annular magnets. The annular magnets build a special kind of periodic permanent magnets (PPM). The radius difference between the adjacent annular magnets is set to half the wavelength of the desire wave mode to maximize the excitation efficiency. In 2D axisymmetric FE simulations, the distribution of the bias magnetic fields and eddy currents was analyzed, and the mode of the generated guided waves was determined. In experiments, the omnidirectional EMATs were fabricated to verify the performance of generating omnidirectional A0 mode Lamb waves. The results prove the performance of the omnidirectional EMATs for effective generation of pure antisymmetric mode Lamb waves at specific frequency. © 2023 IEEE.

关键词： Guided electromagnetic wave propagation

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Stacking, Strain-Engineering Induced Altermagnetism, Multipiezo Effect, and Topological State in Two-Dimensional Materials

arXiv

引用

arXiv 2025年

作者： Xun, Wei Liu, Xin Zhang, Youdong Wu, Yin-Zhong Li, Ping Jiangsu Engineering Research Center for Design and Application of Intelligent Detection Equipment School of Electronic Engineering Jiangsu Vocational College of Electronics and Information Huaian223003 China School of Physical Science and Technology Suzhou University of Science and Technology Suzhou215009 China State Key Laboratory for Mechanical Behavior of Materials Center for Spintronics and Quantum System School of Materials Science and Engineering Xi’an Jiaotong University Shaanxi Xi’an710049 China State Key Laboratory for Surface Physics Department of Physics Fudan University Shanghai200433 China State Key Laboratory of Silicon and Advanced Semiconductor Materials Zhejiang University Hangzhou310027 China

Altermagnetism, as a newly identified form of unconventional antiferromagnetism, enables the removal of spin degeneracy in the absence of net magnetization that provides a platform for the low power consumption and ultra-fast device applications. However, the rare attention has been paid to the relationship between stacking, strain and altermagnet, multipiezo effect and topological state. Here, we propose a mechanism to realize the altermagnet, multipiezo effect, and topological state in two-dimensional materials by the stacking and strain engineering. Based on the analysis of symmetry, we find that the spin splitting feature related to the Ut, PTt, MzUt, or MzPTt symmetries in altermagnet multilayers. In addition, we find that the stacking engineering can effectively realize the transform from antiferromagnetism to altermagnetism and semiconductor to metal for the Jauns bilayer V2SeTeO. More interestingly, the strain not only induces an intriguing multipiezo effect, encompassing the piezovalley, piezomagnetism and piezoelectric, but also achieves the abundant topological phase. Our findings offer a generalized direction for manipulating the spin splitting, valley polarization, and topological states, promoting practical application of valleytronic and spintronic devices based on two-dimensional altermagnets. © 2025, CC BY.

关键词： Antiferromagnetism

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The Design and numerical simulation of a 3D-printed flexible capacitive pressure sensor with a composite structure 7

The Design and numerical simulation of a 3D-printed flexible...

引用

2024 7th International Conference on Mechanical, Electrical and Material Application, MEMA 2024

作者： Chen, Yike Zhang, Hongbo Gao, Yang Yin, Ruixue Shanghai Key Laboratory of Intelligent Sensing and Detection East China University of Science and Technology Shanghai200237 China

Flexible pressure sensors are crucial for many areas, such as electronic skins, human motion, robot monitoring, and medical treatment. However, conventional manufacturing methods limit the speed and accuracy of manufacturing sensor dielectric layers. In this paper, a unique capacitive pressure sensor with a composite structure is introduced that can be fabricated by 3D printing technology. The structure, which has 3D hierarchical pyramids microstructures and porous substrate, can be directly fabricated by a DLP 3D printer. This allows flexible dielectric layers to be fabricated quickly while maintaining their superior performance. The dimension of the produced sensor is 10×10×4.5 mm3. The sensor's design process, numerical simulation, and performance are provided and elucidated. The performance of the sensor is measured between 0 and 1 MPa. It has low hysteresis and high sensitivity (6.83 MPa-1 within the scope of 0 to 0.5 MPa and 2.56 MPa-1 within the scope of 0.5 to 1 MPa). © Published under licence by IOP Publishing Ltd.

关键词： 3D printing

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