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Interfacial DMI in Fe/Pt thin films grown on different buffer layers

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Chinese Physics B 2024年第4期33卷 712-718页

作者：张文君魏菲刘冰周阳康仕寿孙兵 school of Physics and electronic information Weifang UniversityWeifang 261061China school of Physics and State Key Laboratory of Crystal Materials Shandong UniversityJinan 250100China

We study the interfacial Dzyaloshinskii-Moriya interactions(i-DMI)of Fe/Pt bilayers grown on Si substrates with MgO,SiO_(2),or Ta each as a buffer layer on the basis of wave-vector-resolved Brillouin light scattering(BLS)*** obtained i-DMI energy values for Fe/Pt on MgO,Ta,and SiO_(2) buffer layers are 0.359,0.321,and 0.274 mJ/m~2,*** large i-DMI value observed in Fe/Pt system on the MgO buffer layer can be attributed to the good interfacial quality and the Rshaba effect at the MgO/Fe ***,the MgO/Fe/Pt system,benefiting from better sample quality,exhibits a lower damping ***,layer-resolved first-principles calculations are carried out to gain a more in-depth understanding of the origin of the i-DMI in the Fe/Pt *** results indicate that in the Fe(110)/Pt(111)system,the substantial DMI energy between Fe spins at the interface is related to a significant change in spin-orbit coupling(SOC)energy in the neighboring Pt *** contrast,for the MgO(002)/Fe(002)system,both the DMI and its related SOC energy are concentrated at the interfacial Fe *** investigation will provide a valuable insight into the spintronic community in exploring novel devices with chirality dependence.

关键词： Fe/Pt i-DMI BLS ferromagnetic resonance magnetic relaxation

Semiannual oscillation,annual oscillation,quasibiennial oscillation,and solar cycle variation of the OH airglow emission in the mesopause region

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Earth and Planetary Physics 2024年第3期8卷 479-496页

作者： Sheng-Yang Gu Dong Wang YuSong Qin Liang Tang YaFei Wei XianKang Dou electronic information school Wuhan UniversityWuhan 430072China school of Optoelectronic Engineering Chongqing University of Posts and TelecommunicationsChongqing 400065China

The vertically integrated emission rate,centroid altitude,peak emission rate,and peak height of the hydroxyl(OH)airglow were calculated from Thermosphere Ionosphere Mesosphere Energetics and Dynamics(TIMED)/Sounding of the Atmosphere using Broadband Emission Radiometry(SABER)observations to study the seasonal and interannual variations in the intensity and location of the OH *** emission rate is inversely proportional to the height of the emission,with the semiannual oscillation dominating at low latitudes and the annual oscillation dominating at higher *** OH emission is modulated by the quasibiennial oscillation at the equator,and the quasibiennial oscillation signal is weak at other *** represented the vertical transport of atomic oxygen by using atomic oxygen concentrations obtained from a global atmospheric model,the Specified Dynamics Whole Atmosphere Community Climate Model with thermosphere and ionosphere eXtension *** with the amplitudes of the migrating diurnal tide(DW1)calculated from temperature data observed by TIMED/SABER,we found that both the vertical transport of atomic oxygen and DW1 amplitudes in the equatorial region exhibit semiannual oscillation and quasibiennial oscillation,which have a strong correlation with the variations in the amplitude and phase of semiannual oscillation and quasibiennial oscillation in OH *** is likely that the DW1 affects the vertical transport of atomic oxygen that is involved in the reaction to produce O3,thus affecting the OH *** analyzed the relationship between OH emission and solar activity by using the solar radio flux at 10.7 cm as a proxy for solar *** results showed that the OH emission is well correlated with solar activity,and the modulation of OH emission by solar activity has a significant latitudinal *** small correlation between emission height and solar activity indicates that solar activity modulates OH emission mainly thr

关键词： OH airglow semiannual oscillation quasibiennial oscillation solar activity diurnal tide

On Designs of Decentralized Reputation Management for Permissioned Blockchain Networks

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Computer Modeling in Engineering & Sciences 2024年第5期139卷 1755-1773页

作者： Jinyu Chen Long Shi Qisheng Huang Taotao Wang Daojing He school of electronic and optical Engineering Nanjing University of Science and TechnologyNanjing210094China school of Mechanical Engineering and Automation Harbin Institute of TechnologyShenzhen518055China College of electronics and information Engineering Shenzhen UniversityShenzhen518060China school of Computer Science and Technology Harbin Institute of TechnologyShenzhen518055China

In permissioned blockchain networks,the Proof of Authority(PoA)consensus,which uses the election of authorized nodes to validate transactions and blocks,has beenwidely advocated thanks to its high transaction throughput and fault ***,PoA suffers from the drawback of centralization dominated by a limited number of authorized nodes and the lack of anonymity due to the round-robin block proposal *** a result,traditional PoA is vulnerable to a single point of failure that compromises the security of the blockchain *** address these issues,we propose a novel decentralized reputation management mechanism for permissioned blockchain networks to enhance security,promote liveness,and mitigate centralization while retaining the same throughput as traditional *** paper aims to design an off-chain reputation evaluation and an on-chain reputation-aided ***,we evaluate the nodes’reputation in the context of the blockchain networks and make the reputation globally verifiable through smart ***,building upon traditional PoA,we propose a reputation-aided PoA(rPoA)consensus to enhance securitywithout sacrificing *** particular,rPoA can incentivize nodes to autonomously form committees based on reputation authority,which prevents block generation from being tracked through the randomness of reputation ***,we develop a reputation-aided fork-choice rule for rPoA to promote the network’s ***,experimental results show that the proposed rPoA achieves higher security performance while retaining transaction throughput compared to traditional PoA.

关键词： Blockchain reputation management PoA throughput security decentralization

Rational construction of CuFe_(2)O_(4)@C/Cd_(0.9)Zn_(0.1)S S-scheme heterojunction photocatalyst for extraordinary photothermal-assisted photocatalytic H_(2) evolution

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Journal of Energy Chemistry 2024年第5期92卷 240-249页

作者： Dong Zhang Minghui Zhu Ran Qin Peixian Chen Maoye Yin Dafeng Zhang Junchang Liu Hengshuai Li Xipeng Pu Peiqing Cai school of Physics Science and information Technology Shandong Key Laboratory of Optical Communication Science and TechnologyLiaocheng UniversityLiaocheng 252000ShandongChina school of Materials Science and Engineering Shandong Provincial Key Laboratory of Chemical Energy Storage and Novel Cell TechnologyLiaocheng UniversityLiaocheng 252000ShandongChina College of optical and electronic Technology China Jiliang UniversityHangzhou 310018ZhejiangChina

Rational design of photocatalyst to maximize the use of sunlight is one of the issues to be solved in photocatalysis *** this study,the CuFe_(2)O_(4)@C/Cd_(0.9)Zn_(0.1)S(CFO@C/CZS)S-scheme photocatalyst with photothermal effect was synthesized by ultrasonic self-assembly combined with *** dark CFO@C absorbed visible light and partly converted into heat to promote the hydrogen evolution *** presence of heterojunctions inhibited the photogenerated electron-hole *** graphite-carbon layer provided a stable channel for electron transfer,and the presence of magnetic CFO made recycle *** the action of photothermal assistance and heterojunction,the hydrogen evolution rate of the optimal CFO@C/CZS was 80.79 mmol g^(-1) h^(-1),which was 2.55 times and 260.61 times of that of pure CZS and CFO@C,***,the composite samples also exhibit excellent stability and a wide range of environmental *** experimental tests and first-principles simulation calculation methods,the plausible mechanism of photoactivity enhancement was *** work provided a feasible strategy of photothermal assistance for the development of heterojunction photocatalysts with distinctive hydrogen evolution.

关键词： Photothermal effect S-scheme heterojunction Photocatalytic hydrogen evolution First-principles calculations

λ/20-Thick cavity for mimicking electromagnetically induced transparency at telecommunication wavelengths

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Advanced Photonics 2024年第3期6卷 42-50页

作者： Hua Lu Shouhao Shi Dikun Li Shuwen Bo Jianxu Zhao Dong Mao Jianlin Zhao Northwestern Polytechnical University School of Physical Science and Technology MOE Key Laboratory of Material Physics and Chemistry under Extraordinary Conditions Key Laboratory of Light-Field Manipulation and Information Acquisition Ministry of Industry and Information TechnologyShaanxi Key Laboratory of Optical Information Technology

optical cavities play crucial roles in enhanced light–matter interaction, light control, and optical communications, but their dimensions are limited by the material property and operating *** planar cavities are urgently in demand for large-area and integrated optical devices. However,extremely reducing the planar cavity dimension is a critical challenge, especially at telecommunication wavelengths. Herein, we demonstrate a type of ultrathin cavities based on large-area grown Bi2Te3topological insulator（TI） nanofilms, which present distinct optical resonance in the near-infrared region. The result shows that the Bi2Te3TI material presents ultrahigh refractive indices of >6 at telecommunication wavelengths. The cavity thickness can approach 1/20 of the resonance wavelength, superior to those of planar cavities based on conventional Si and Ge high refractive index materials. Moreover, we observed an analog of the electromagnetically induced transparency（EIT） effect at telecommunication wavelengths by depositing the cavity on a photonic crystal. The EIT-like behavior is derived from the destructive interference coupling between the nanocavity resonance and Tamm plasmons. The spectral response depends on the nanocavity thickness, whose adjustment enables the generation of obvious Fano *** experiments agree well with the simulations. This work will open a new door for ultrathin cavities and applications of TI materials in light control and devices.

关键词： Bismuth Tellurium Refractive index Nanofilms Photonic crystals Transparency Silver Telecommunications Crystals Plasmons

Novel self-embedding holographic watermarking image encryption protection scheme

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Chinese Physics B 2024年第5期33卷 281-290页

作者：王励年周楠润孙博曹颖鸿牟俊 school of information Science and Engineering Dalian Polytechnic UniversityDalian 116034 China school of electronic and Electrical Engineering Shanghai University of Engineering ScienceShanghai 201620China

For digital image transmission security and information copyright,a new holographic image self-embedding watermarking encryption scheme is ***,the plaintext is converted to the RGB three-color channel,the corresponding phase hologram is obtained by holographic technology and the watermark is self-embedded in the frequency ***,by applying the Hilbert transform principle and genetic center law,a complete set of image encryption algorithms is constructed to realize the encryption of image ***,simulation results and security analysis indicate that the scheme can effectively encrypt and decrypt image information and realize the copyright protection of *** introduced scheme can provide some support for relevant theoretical research,and has practical significance.

关键词： color image encryption Hilbert transform self-embedding watermark holographic technology

Suppression of modulation-induced polarization error in spliceless open-loop fiber optic gyroscope [Invited]

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Chinese Optics Letters 2024年第7期22卷 6-11页

作者： Lin Chen Peitong He Biqiang Jiang Jianlin Zhao Key Laboratory of Light Field Manipulation and information Acquisition and Shaanxi Key Laboratory of Optical Information TechnologySchool of Physical Science and TechnologyNorthwestern Polytechnical UniversityXi’an 710129China Zhejiang Lab Hangzhou 311100China

The suppression of polarization cross talk in lead zirconate titanate phase modulators as a key error source has been challenging for open-loop fiber optic gyroscopes(FOGs).We developed a polarization-diversity optical frequency domain reflectometry(OFDR)to measure the distributed modulation polarization error in the *** error contributes 8×10^(−6) rad to FOG’s bias *** a UV-fabricated in-fiberλ/4 wave plate and polarization-mode converter with fiber taper technology,the modulation error has been suppressed by 15 dB in assembled *** approach reduced error with temperature from 25°/h to 0.7°/h,meeting the requirements of control-level gyroscopes with bias errors less than 1°/h.

关键词： fiber optic gyroscope inline wave plate optical frequency domain reflectometry polarization-mode converter.

YOLO-DD:Improved YOLOv5 for Defect Detection

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Computers, Materials & Continua 2024年第1期78卷 759-780页

作者： Jinhai Wang Wei Wang Zongyin Zhang Xuemin Lin Jingxian Zhao Mingyou Chen Lufeng Luo school of electronic and information Engineering Foshan UniversityFoshan528000China school of Mechatronic Engineering and Automation Foshan UniversityFoshan528000China

As computer technology continues to advance,factories have increasingly higher demands for detecting ***,detecting defects in a plant environment remains a challenging task due to the presence of complex backgrounds and defects of varying shapes and *** address this issue,this paper proposes YOLO-DD,a defect detectionmodel based on YOLOv5 that is effective and *** improve the feature extraction process and better capture global information,the vanilla YOLOv5 is augmented with a new module called Relative-Distance-Aware Transformer(RDAT).Additionally,an information Gap Filling Strategy(IGFS)is proposed to improve the fusion of features at different *** classic lightweight attention mechanism Squeeze-and-Excitation(SE)module is also incorporated into the neck section to enhance feature expression and improve the model’s *** results on the NEU-DET dataset demonstrate that YOLO-DDachieves competitive results compared to state-of-the-art methods,with a 2.0% increase in accuracy compared to the original YOLOv5,achieving 82.41% accuracy and38.25FPS(framesper second).Themodel is also testedon a self-constructed fabric defect dataset,and the results show that YOLO-DD is more stable and has higher accuracy than the original YOLOv5,demonstrating its stability and generalization *** high efficiency of YOLO-DD enables it to meet the requirements of industrial high accuracy and real-time detection.

关键词： YOLO-DD defect detection feature fusion attention mechanism

Stochastic Gradient Compression for Federated Learning over Wireless Network

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China Communications 2024年第4期21卷 230-247页

作者： Lin Xiaohan Liu Yuan Chen Fangjiong Huang Yang Ge Xiaohu school of electronic and information Engineering South China University of TechnologyGuangzhou 510641China Key Laboratory of Dynamic Cognitive System of Electromagnetic Spectrum Space Ministry of Industry and Information TechnologyNanjing University of Aeronautics and AstronauticsNanjing 210016China school of electronic information and Communications Huazhong University of Science and TechnologyWuhan 430074China

As a mature distributed machine learning paradigm,federated learning enables wireless edge devices to collaboratively train a shared AI-model by stochastic gradient descent(SGD).However,devices need to upload high-dimensional stochastic gradients to edge server in training,which cause severe communication *** address this problem,we compress the communication by sparsifying and quantizing the stochastic gradients of edge *** first derive a closed form of the communication compression in terms of sparsification and quantization ***,the convergence rate of this communicationcompressed system is analyzed and several insights are ***,we formulate and deal with the quantization resource allocation problem for the goal of minimizing the convergence upper bound,under the constraint of multiple-access channel *** show that the proposed scheme outperforms the benchmarks.

关键词： federated learning gradient compression quantization resource allocation stochastic gradient descent(SGD)