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高斯白噪声背景下时移相位差校正法的频率估计精度分析

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振动工程学报 2007年第3期20卷 274-279页

作者：杨志坚丁康华南理工大学汽车工程学院

推导了高斯白噪声背景下加任意对称窗函数截断的谐波信号用时移相位差校正法进行离散频谱校正时的归一化频率估计误差的统计公式;针对加矩形窗和加Hanning窗,通过与仿真模拟结果的对比分析验证了其正确性,并分析了在某些情况下产生偏离... 详细信息

推导了高斯白噪声背景下加任意对称窗函数截断的谐波信号用时移相位差校正法进行离散频谱校正时的归一化频率估计误差的统计公式;针对加矩形窗和加Hanning窗,通过与仿真模拟结果的对比分析验证了其正确性,并分析了在某些情况下产生偏离的原因;研究了谐波信号本身参数和校正方法选取的参数对估计误差的影响,并比较了加矩形窗和加Hanning窗时的估计误差。

关键词：离散频谱相位差误差高斯白噪声

Functional Connectivity Difference Detected in Bilateral Occipital Lobes Between the Abacus Experts and Control Groups: Using Nonlinear Processing Method

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Chinese Journal of Biomedical Engineering(English Edition) 2010年第1期19卷 16-21页

作者： WANG Zhi-kang ding Wen-hong SUN Jian-zhong The Second Affiliated Hospital Zhejiang University College of Medicine Hangzhou 310009 China

Objective:This paper is to investigate functional connectivity differences between the abacus experts and control groups by using nonlinear processing method spatiotemporal Lyapunov ***:11 right-handed healthy control children and 12 abacus children were undergone functional magnetic resonance imaging(fMRI).After preprocessing fMRI data with SPM,linear and nonlinear methods for connectivity analysis were both ***:Connectivity differences between the two groups were statistically P<0.05 by the correlation method,while the P value by the nonlinear method were P<***:There are significant differences between the two groups in functional connectivity of bilateral occipital *** nonlinear method proposed here seems to be more specific compared with the common linear correlation method.

关键词： functional connectivity neural correlate nonlinear dynamics

Freestanding carbon encapsulated mesoporous vanadium nitride nanowires enable highly stable sulfur cathodes for lithium-sulfur batteries

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Freestanding carbon encapsulated mesoporous vanadium nitride...

Natural vibration and critical velocity of translating Timoshenko beam with non-homogeneous boundaries

中国化学会第三届中国能源材料化学研讨会

作者： Xingxing Li kang ding Biao Gao Kaifu Huo The State Key Laboratory of Refractories and Metallurgy School of Materials and MetallurgyWuhan University of Science and Technology Wuhan National Laboratory for Optoelectronics (WNLO) and School of Optical and Electronic Information Huazhong University of Science and Technology

Lithium-sulfur(Li-S) battery is one of the most promising energy storage systems due to its large energy density of 2560 Wh kg However,severe shuttle effect of polysulfide intermediates,poor conductivity of S and larg...

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Applied Mathematics and Mechanics(English Edition) 2024年第9期45卷 1523-1538页

作者： Yanan LI Jieyu ding Hu ding Liqun CHEN Shanghai Institute of Applied Mathematics and Mechanics Shanghai Key Laboratory of Mechanics in Energy EngineeringShanghai Frontier Science Center of MechanoinformaticsSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai 200072China School of Mathematics and Statistics Qingdao UniversityQingdao 266071Shandong ProvinceChina

In most practical engineering applications,the translating belt wraps around two fixed *** boundary conditions of the dynamic model are typically specified as simply supported or fixed *** this paper,non-homogeneous boundaries are introduced by the support *** the translating belt as the mechanical prototype,the vibration characteristics of translating Timoshenko beam models with nonhomogeneous boundaries are investigated for the first *** governing equations of Timoshenko beam are deduced by employing the generalized Hamilton's *** effects of parameters such as the radius of wheel and the length of belt on vibration characteristics including the equilibrium deformations,critical velocities,natural frequencies,and modes,are numerically calculated and *** numerical results indicate that the beam experiences deformation characterized by varying curvatures near the *** radii of the wheels play a pivotal role in determining the change in trend of the relative difference between two beam *** the results unearths that the relative difference in equilibrium deformations between the two beam models is more pronounced with smaller-sized *** the two wheels are of equal size,the critical velocities of both beam models reach their respective *** addition,the relative difference in natural frequencies between the two beam models exhibits nonlinear variation and can easily exceed 50%.Furthermore,as the axial velocities increase,the impact of non-homogeneous boundaries on modal shape of translating beam becomes more *** dealing with non-homogeneous boundaries is challenging,beam models with non-homogeneous boundaries are more sensitive to parameters,and the differences between the two types of beams undergo some interesting variations under the influence of non-homogeneous boundaries.

关键词： translating beam Timoshenko beam non-homogeneous boundary natural frequency critical velocity

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改变窗长相位差校正法的改进与抗噪性能分析

华南理工大学学报（自然科学版） 2007年第10期35卷 210-213页

作者：丁康杨志坚华南理工大学汽车工程学院广东广州510640

提出了一种改进的改变窗长相位差校正法来估计谐波信号的频率,与原方法相比,改进后的方法只需做一次快速傅立叶变换(FFT)和一次单点离散傅立叶变换(DFT),提高了运算速度.分析了改进方法的抗噪声性能,推导出了在高斯白噪声背景下频率估... 详细信息

提出了一种改进的改变窗长相位差校正法来估计谐波信号的频率,与原方法相比,改进后的方法只需做一次快速傅立叶变换(FFT)和一次单点离散傅立叶变换(DFT),提高了运算速度.分析了改进方法的抗噪声性能,推导出了在高斯白噪声背景下频率估计误差的方差公式,并通过仿真计算验证了推导公式的正确性.仿真结果表明改进后的方法具有更强的抗噪能力.

关键词：频率估计相位差抗噪频谱分析校正

Electronic structure tuning of layered double hydroxides for electrochemical sensing and its biomedical applications

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Science China Chemistry 2024年第11期67卷 3614-3630页

作者： Kun Wang Zhiying Cao Qihang ding Jiyoung Yoo Nem Singh Heemin kang Lin Wang Lin Xu Jong Seung Kim School and Hospital of Stomatology Jilin Provincial Key Laboratory of Tooth Development and Bone Remodeling Jilin University State Key Laboratory on Integrated Optoelectronics Collage of Electronic Science and Engineering Jilin University Department of Chemistry Korea University Department of Materials Science and Engineering Korea University

Modifying the electrodes of electrochemical sensors is critical to enhance sensitivity, selectivity, and stability, ultimately improving both their effectiveness and performance. In this paper, recent advancements in electrochemical sensors are reviewed,focusing on the utilization of layered double hydroxides(LDHs). The first section explores the advantageous and disadvantageous aspects of electrochemical sensing. Benefits include rapid response, ease of operation, and cost-effectiveness,while drawbacks concern the potential instability of prolonged use, susceptibility to interference, and the risk of biomolecule inactivation. Following this, the second section delves into the synthesis, constituents, and structure of LDHs. Moreover, after introducing the chemical mechanisms and functions of LDHs in electrochemical sensors, we concentrate on diverse modifying materials of LDHs and their different performances. Finally, the applications of LDHs in electrochemical sensing across different fields are discussed. This review aims to facilitate the continued advancement for applying LDHs in electrochemical sensors, as well as inspire the evolution of electrochemical sensing technology.

关键词： layered double hydroxides electrochemical sensor biological field modified electrode

Local tetragonal distortion of Pt alloy catalysts for enhanced oxygen reduction reaction efficiency

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Carbon Energy 2024年第7期6卷 41-52页

作者： Xiaoke Li Xiao Duan kang Hua Yongkang Wu Zhiyan Rui Rui ding Aidong Li Chen Ouyang Jia Li Ting Li Jianguo Liu National Laboratory of Solid-State Microstructures College of Engineering and Applied Sciencesand Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjingChina Long-Life Fuel Cell Key Laboratory in Sichuan Province Dongfang Electric(Chengdu)Hydrogen Fuel Cell Technology Co.Ltd.ChengduChina Institute of Energy Power Innovation North China Electric Power UniversityBeijingChina

Platinum-based alloy nanoparticles are the most attractive catalysts for the oxygen reduction reaction at present,but an in-depth understanding of the relationship between their short-range structural information and catalytic performance is still ***,we present a synthetic strategy that uses transition-metal oxide-assisted thermal ***/C catalysts with localized tetragonal distortion were obtained by controlling the thermal diffusion process of transition-metal *** localized structural distortion induced a significant strain effect on the nanoparticle surface,which further shortened the length of the Pt-Pt bond,improved the electronic state of the Pt surface,and enhanced the performance of the ***/C catalysts with special short-range structures achieved excellent mass activity(2.27 Amg_(Pt)^(-1))and specific activity(3.34 A cm^(-2)).In addition,the localized tetragonal distortion-induced surface compression of the Pt skin improved the stability of the *** mass activity decreased by only 13%after 30,000 *** catalyst activity and excellent durability have also been demonstrated in the proton exchange membrane fuel cell *** study provides valuable insights into the development of advanced Pt-based nanocatalysts and paves the way for reducing noble-metal loading and increasing the catalytic activity and catalyst stability.

关键词： electrocatalysts fuel cells local tetragonal distortion oxygen reduction

Whittle’s Index Based Sensor Scheduling for Multiprocess Systems Under DoS Attacks

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Journal of Systems Science & Complexity 2024年第1期37卷 329-350页

作者： CAI Zai ding Kemi Shenzhen Key Laboratory of Control Theory and Intelligent Systems Southern University of Science and TechnologyShenzhen 518055China.

In this paper,the authors consider how to design defensive countermeasures against DoS attacks for remote state estimation of multiprocess *** each system,a sensor will measure its state and transmits the data packets through an unreliable channel which is vulnerable to be jammed by an *** limited communication bandwidth,only a subset of sensors are allowed for data transmission,and how to select the optimal one to maximize the accuracy of remote state estimation is the focus of the proposed *** authors first formulate this problem as a Markov decision process and investigate the existence of optimal ***,the authors demonstrate the piecewise monotonicity structure of optimal *** the difficulty of obtaining an optimal policy of large-scale problems,the authors develop a suboptimal heuristic policy based on the aforementioned policy structure and Whittle’s ***,a closed form of the indices is derived in order to reduce implementation complexity of proposed scheduling policy and numerical examples are provided to illustrate the proposed developed results.

关键词： DoS attacks Kalman filter remote state estimation Whittle’s index.

Deep structure of the Southeast Asian curved subduction system and its dynamic process

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Journal of Oceanology and Limnology 2024年第3期42卷 701-704页

作者： Weiwei ding Key Laboratory of Submarine Geoscience&Second Institute of Oceanography Ministry of Natural ResourcesHangzhou 310012China School of Oceanography Shanghai Jiao Tong UniversityShanghai 200030China

The deep structure,material circulation,and dynamic processes in the Southeast Asia have long been an elusive scientific puzzle due to the lack of systematic scientific observations and recognized theoretical *** on the deep seismic tomography using long-period natural earthquake data,in this study,the deep structure and material circulation of the curved subduction system in Southeast Asia was studied,and the dynamic processes since 100 million years ago was *** is pointed out that challenges still exist in the precise reconstruction of deep mantle structures of the study area,the influence of multi-stage subduction on deep material exchange and shallow magma activity,as well as the spatiotemporal evolution and coupling mechanism of multi-plate *** work should focus on high-resolution land-sea joint 3-D seismic tomography imaging of the curved subduction system in the Southeast Asia,combined with geochemical analysis and geodynamic modelling works.

关键词： curved subduction system deep structure material recycling dynamic process Southeast Asia