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Two-dimensional characterization of three-dimensional magnetic bubbles in Fe3Sn2 nanostructures

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National Science Review 2021年第6期8卷 188-194页

作者： Jin Tang Yaodong Wu Lingyao Kong Weiwei Wang Yutao Chen Yihao Wang Y.Soh Yimin Xiong Mingliang Tian Haifeng Du anhui Province key laboratory of Condensed Matter Physics at Extreme Conditions High Magnetic Field Laboratory of the Chinese Academy of Sciencesand University of Science and Technology of China Universities Joint key laboratory of Photoelectric detection Science and technology in anhui Province Hefei Normal University School of Physics and Materials Science Anhui University Institute of Physical Science and Information technology Anhui University Paul Scherrer Institute

We report differential phase contrast scanning transmission electron microscopy(TEM) of nanoscale magnetic objects in Kagome ferromagnet Fe3 Sn2 nanostructures. This technique can directly detect the deflection angle of a focused electron beam, thus allowing clear identification of the real magnetic structures of two magnetic objects including three-ring and complex arch-shaped vortices in Fe3 Sn2 by Lorentz-TEM imaging. Numerical calculations based on real material-specific parameters well reproduced the experimental results, showing that the magnetic objects can be attributed to integral magnetizations of two types of complex three-dimensional(3 D) magnetic bubbles with depth-modulated spin twisting. Magnetic configurations obtained using the high-resolution TEM are generally considered as two-dimensional(2 D)magnetic objects previously. Our results imply the importance of the integral magnetizations of underestimated 3 D magnetic structures in 2 D TEM magnetic characterizations.

关键词： skyrmion skyrmion bubbles three-dimensional magnetic structures differential phase contrast scanning transmission electron microscopy micromagnetics

Comparision between Ga- and N-polarity InGaN solar cells with gradient-In-composition intrinsic layers

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Chinese Physics B 2016年第10期25卷 549-553页

作者：鲁麟李明潮吕琛高文根江明许福军陈其工 anhui key laboratory of detection technology and Energy Saving Devices Anhui Polytechnic University College of Electrical Engineering Anhui Polytechnic University Research Center for Wide Gap Semiconductor School of Physics Peking University

Performances of Ga-and N-polarity solar cells(SCs) adopting gradient-In-composition intrinsic layer(IL) are *** is found the gradient ILs can greatly weaken the negative influence from the polarization effects for the Gapolarity case,and the highest conversion efficiency(η) of 2.18%can be obtained in the structure with a linear increase of In composition in the IL from bottom to *** is mainly attributed to the adsorptions of more photons caused by the higher In composition in the IL closer to the p-GaN window *** contrast,for the N-polarity case,the SC structure with an InGaN IL adopting fixed In composition prevails over the ones adopting the gradient-In-composition IL,where the highest η of 9.28%can be obtained at x of 0.62.N-polarity SC structures are proven to have greater potential preparations in high-efficient InGaN SCs.

关键词： InGaN solar cell polarity

A Sparsity Adaptive Greedy Iterative Algorithm for Compressed Sensing

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A Sparsity Adaptive Greedy Iterative Algorithm for Compresse...

A probability theory for filtered ghost imaging

第37届中国控制会议

作者： Li Wang Lina Xun Dexiang Zhang Yi Xia College of Electrical Engineering and Automation Anhui University key laboratory of polarization imaging detection technology in anhui Province

Aiming at the problem of signal reconstruction with unknown sparsity in compressed sensing, an improved iterative greedy algorithm is proposed to signal reconstruction from low sampling rate. Firstly, a sparsity estimation strategy is used to estimate the sparsity and the true support set of target signal, and then the residual is initialized with the estimated value. In order to optimize the estimated value, it is necessary to determine the direction of the iteration before the iteration begins. The proposed algorithm is associated with the ideas of adaptive, backtracking and greedy choice to iteratively refine. The simulation results show that the proposed algorithm performs better than that of OMP, CoSaMP and SAMP algorithms for both one-dimensional signal and two-dimensional image signal, and the algorithm has better practical application value.

关键词： Compressed sensing sparsity estimation reconstruction algorithm

来源： cnki会议评论

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Chinese Physics B 2023年第4期32卷 329-337页

作者：刘忠源孟少英陈希浩 key laboratory of Optoelectronic Devices and detection technology College of PhysicsLiaoning UniversityShenyang 110036China

Based on probability density functions,we present a theoretical model to explain filtered ghost imaging(FGI)we first proposed and experimentally demonstrated in 2017[***.425290(2017)].An analytic expression for the joint intensity probability density functions of filtered random speckle fields is derived according to their probability ***,the normalized second-order intensity correlation functions are calculated for the three cases of low-pass,bandpass and high-pass filterings to study the resolution and visibility in the FGI *** simulations show that the resolution and visibility predicted by our model agree well with the experimental results,which also explains why FGI can achieve a super-resolution image and better visibility than traditional ghost imaging.

关键词： ltered ghost imaging probability density function super-resolution

Resolution-enhanced single-pixel imaging using the Hadamard transform matrix

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Chinese Physics B 2023年第12期32卷 652-656页

作者：别书航王晨晖吕瑞兵鲍倩倩付强孟少英陈希浩 key laboratory of Optoelectronic Devices and detection technology College of PhysicsLiaoning UniversityShenyang 110036China

We propose a single-pixel imaging(SPI)method to achieve a higher-resolution image via the Hadamard transform *** traditional SPI schemes,this new method recovers images by correlating single-pixel signals with synchronized transformed patterns of Hadamard bases that are actually projected onto the digital micromirror *** transform pattern is obtained through the inverse Fourier transform of the pattern acquired by Gaussian filtering of each Hadamard basis in the frequency *** proposed scheme is based on a typical SPI experimental setup and does not add any hardware complexity,enabling the transformation of Hadamard matrices and image reconstruction through data processing ***,this approach could be considered as an alternative option for achieving fast SPI in a diffraction-limited imaging system,without the need for additional hardware.

关键词： single-pixel imaging Gaussian filtering resolution enhancement

Resistive switching performance improvement of In GaZnO-based memory device by nitrogen plasma treatment

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Journal of Materials Science & technology 2020年第14期47卷 1-6页

作者： Li Zhang Zhong Xu Jia Han Lei Liu Cong Ye Yi Zhou Wen Xiong Yanxin Liu Gang He Faculty of Physics and Electronic Science Hubei UniversityHubei Key Laboratory of Ferro-&Piezoelectric Materials and DevicesHubei Key Laboratory of Applied MathematicsWuhan430062China School of Physics and Materials Science Radiation Detection Materials&Device LabAnhui UniversityHefei230039China School of Microelectronics Tianjin Key Laboratory of Imaging and Sensing Microelectronic TechnologyTianjin UniversityTianjin300072China

With the demand of flat panel display development,utilizing the non-volatile memory devices based on indium-gallium-zinc-oxide(IGZO)film may be integrated with IGZO thin film transistors(TFTs)to accomplish system-on-panel *** this work,1×1μm^2 via hole structure IGZO based memory device was fabricated and the resistive switching(RS)behavior was *** inserting a nitrogen doping layer IGZO:N by plasma treatment in Pt/IGZO/Ti N device,highly improved RS performance including lower forming voltage,remarkable uniformity,large memory window of 102,retention property of 10^4 s at 125℃,excellent pulse endurance of 10^7 cycles were *** X-ray photoelectron spectroscopy analysis indicates that plasma doping method can evenly dope nitrogen and induce more non-lattice oxygen in the IGZO *** is deduced that the N atoms of the inserting layer can influence the random formation of oxygen vacancy type conducting filaments,which results in more stable and uniform performance.

关键词： Memory device Resistive switching Plasma treatment Indium-gallium-zinc-oxide Memristor

Study of polarization Image Color Fusion Method Based on Color Transfer

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Journal of Beijing Institute of technology 2010年第2期19卷 196-201页

作者：王霞李海兰文璇金伟其白廷柱张晓 key laboratory of Photoelectronic imaging technology and System Beijing Institute of Technology

Based on the characteristics that human eyes are sensitive to brightness and color, the lightness information of visible image and degree of linear polarization and polarization angle were fused in hue-saturation- value（HSV） space. To meet the observation of human eyes, hue adjustment based on color transfer was carried out to the fused image and hue was adjusted by polynomial fitting method. Hue adjustment method was improved considering the complicated real mapping relationship between hue gray scale of fused image and reference template image. The result shows that the color fusion method presented in this paper is superior to the traditional pseudo-color method and it is helpful to recognize the target from the environment correctly. The fusion result can reflect the difference of object＇s polarization characteristic, and get a natural fused image effect.

关键词： color transfer polarization image color image fusion

Molecular exchange and passivation at interface afford high-performing perovskite solar cells with efficiency over 24%

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Journal of Energy Chemistry 2023年第7期82卷 219-227,I0005页

作者： Jianjun Sun Wangchao Chen Yingke Ren Yunjuan Niu Zhiqian Yang Li'e Mo Yang Huang Zhaoqian Li Hong Zhang Linhua Hu key laboratory of Photovoltaic and Energy Conservation Materials Institute of Solid State PhysicsHFIPSChinese Academy of SciencesHefei 230031AnhuiChina School of Chemistry and Chemical Engineering Anhui Province Key Laboratory of Advanced Catalytic Materials and Reaction EngineeringHefei University of TechnologyHefei 230009AnhuiChina College of Science Hebei University of Science and TechnologyShijiazhuang 050018HebeiChina Hebei Computational Optical imaging and Photoelectric detection technology Innovation Center Hebei International Joint Research Center for Computational Optical Imaging and Intelligent SensingSchool of Mathematics and Physics Science and EngineeringHebei University of EngineeringHandan 056038HebeiChina University of Science and technology of Chin1 Anhui 230026HefeiChina

The interface is crucial for perovskite solar cells(PSCs).However,voids at interfaces induced by the trapped hygroscopic dimethyl sulfoxide(DMSO)can reduce charge extraction and accelerate the film degradation,seriously damaging the efficiency and *** this work,4,4’-dinonyl-2,2’-dipyridine(DN-DP),a Lewis base with long alkyl chains is introduced to solve this *** calculated and experimental results confirm that the dipyridyl group on DN-DP can more strongly coordinate with Pb^(2+)than that of the S=O group on *** strong coordination effect plays a crucial role in removing the DMSO-based adduct and reducing the formation of *** to the electron-donating properties of pyridine,the existence of DN-DP in the perovskite film can passivate the defects and optimize the energy level alignment of the perovskite *** open-circuit voltage(VOC)of the DN-DP-based PSC is improved from 1.107 V(control device)to 1.153 V,giving rise to a power conversion efficiency(PCE)of24.02%.Furthermore,benefiting from the moisture resistance stemming from the hydrophobic nonyl group,the PCE retains 90.4%of the initial performance after 1000 h of storage in the ambient condition.

关键词： Perovskite solar cell Anti-solvent 4 4′-Dinonyl-2 2′-dipyridine Optimized interfaceStability

Effects of laser beam divergence angle on airborne LIDAR positioning errors

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Journal of Beijing Institute of technology 2012年第2期21卷 278-284页

作者：姜利芳蓝天顾美霞倪国强 key laboratory of Photo-electronic imaging technology and System Beijing Institute of Technology

The influence of laser beam divergence angle on the positioning accuracy of scanning airborne light detection and ranging （LIDAR） is analyzed and simulated. Based on the data process and positioning principle of airborne LIDAR, the errors from pulse broadening induced by laser beam di vergence angle are modeled and qualitatively analyzed for different terrain surfaces. Simulated results of positioning errors and suggestions to reduce them are given for the flat surface, the downhill of slope surface, and the uphill surface.

关键词： Kairborne light detection and ranging (LIDAR) positioning error laser beam divergenceangle slope angle scan angle