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NN-based Output Tracking for More General Stochastic Nonlinear Systems with Unknown Control Coefficients

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International Journal of Automation and computing 2017年第3期14卷 350-359页

作者： Na Duan hui-fang min School of Electrical Engineering & Automation Jiangsu Normal UniversityXuzhou 221116 China

This paper considers the output tracking problem for more general classes of stochastic nonlinear systems with unknown control coefficients and driven by noise of unknown covariance. By utilizing the radial basis function neural network approximation method and backstepping technique, we successfully construct a controller to guarantee the solution process to be bounded in *** tracking error signal is 4th-moment semi-globally uniformly ultimately bounded（SGUUB） and can be regulated into a small neighborhood of the origin in probability. A simulation example is given to demonstrate the effectiveness of the control scheme.

关键词： Stochastic nonlinear systems unknown control coefficients output tracking neural networks backstepping

Origin of Negative Imaginary Part of Effective Permittivity of Passive Materials

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Chinese Physics Letters 2017年第9期34卷 105-108页

作者： Kai-Lun Zhang Zhi-Ling Hou Ling-Bao Kong hui-min fang Ke-Tao Zhan School of Science ＆ Beijing Laboratory of Enyironmentally Harmful Chemicals Assessment Beijing University of Chemical Technology Beijing 100029 Key of Science Beijing Technology and Business University Beijing 100048

The anti-resonant phenomenon of effective electromagnetic parameters of metamaterials has aroused controversy due to negative imaginary permittivity or permeability. It is experimentally found that the negative imaginary permittivity can occur for the natural passive materials near the Fabry Perot resonances. We reveal the nature of negative imaginary permittivity, which is correlated with the magnetoelectric coupling. The anti-resonance of permittivity is a non-inherent feature for passive materials, while it can be inherent for devices or metamaterials. Our finding validates that the negative imaginary part of effective permittivity does not contradict the second law of thermodynamics for metamaterials owing to the magnetoelectric coupling.

关键词： Origin of Negative Imaginary Part of Effective Permittivity of Passive Materials FPR

Machine learning-based grayscale analyses for lithofacies identification of the Shahejie formation, Bohai Bay Basin, China

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Petroleum Science 2025年第1期22卷 42-54页

作者： Yu-Fan Wang Shang Xu fang Hao hui-min Liu Qin-Hong Hu Ke-Lai Xi Dong Yang National Key Laboratory of Deep Oil and Gas China University of Petroleum (East China) Shengli Oilfield Branch Company SINOPEC

It is of great significance to accurately and rapidly identify shale lithofacies in relation to the evaluation and prediction of sweet spots for shale oil and gas reservoirs. To address the problem of low resolution in logging curves, this study establishes a grayscale-phase model based on high-resolution grayscale curves using clustering analysis algorithms for shale lithofacies identification, working with the Shahejie Formation, Bohai Bay Basin, China. The grayscale phase is defined as the sum of absolute grayscale and relative amplitude as well as their features. The absolute grayscale is the absolute magnitude of the gray values and is utilized for evaluating the material composition(mineral composition + total organic carbon) of shale, while the relative amplitude is the difference between adjacent gray values and is used to identify the shale structure type. The research results show that the grayscale phase model can identify shale lithofacies well, and the accuracy and applicability of this model were verified by the fitting relationship between absolute grayscale and shale mineral composition, as well as corresponding relationships between relative amplitudes and laminae development in shales. Four lithofacies are identified in the target layer of the study area: massive mixed shale, laminated mixed shale, massive calcareous shale and laminated calcareous shale. This method can not only effectively characterize the material composition of shale, but also numerically characterize the development degree of shale laminae, and solve the problem that difficult to identify millimeter-scale laminae based on logging curves, which can provide technical support for shale lithofacies identification, sweet spot evaluation and prediction of complex continental lacustrine basins.

关键词： Shale Machine learning Absolute grayscale Relative amplitude Grayscale phase model Lithofacies identification

Corrosion resistance of high-alumina graphite based refractories to the smelting reduction melts

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材料科学与工程（中英文版） 2008年第12期2卷 49-53页

作者： LIU Qing-cai ZHENG hui-min LU Cun-fang GAO Wei School of Material Science and Engineering Chongqing University Chongqing 400044 China

New Insights on Gamma-Ray Burst Radiation Mechanisms from Multiwavelength Observations

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Research in Astronomy and Astrophysics 2025年第2期25卷 3-12页

作者： Yu-Hua Yao fang-Sheng min Shi Chen Yi-Qing Guo College of Physics Chongqing University Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Wisconsin Ice Cube Particle Astrophysics Center University of Wisconsin–Madison University of Chinese Academy of Sciences School of Physics and Astronomy Yunnan University Tianfu Cosmic Ray Research Center

The study of high-energy gamma-ray emission from gamma-ray bursts(GRBs) involves complex synchrotron radiation and synchrotron self-Compton(SSC) scattering mechanisms with multiple parameters exhibiting a wide distribution. Recent advancements in GRB research, particularly the observation of very high energy(VHE,>100 Ge V) radiation, have ushered in a new era of multiwavelength exploration, offering fresh perspectives and limitations for understanding GRB radiation mechanisms. This study aimed to leverage VHE observations to refine constraints on synchrotron + SSC radiation from electrons accelerated by forward shocks. By analyzing two external environments—the uniform interstellar medium and stratified stellar wind medium, we conducted spectral and variability fitting for five specific bursts(GRB 180720B, GRB 190114C, GRB 190829A, GRB 201216C, and GRB 221009A) to identify the optimal parameters characterizing these events. A comparative analysis of model parameter distributions with and without VHE radiation observations reveals that the magnetic energy equipartition factor εBis more concentrated with VHE emissions. This suggests that VHE emissions may offer greater constraints on this microphysical parameter. Additionally, we found that the energy budget between VHE and ke V–Me V γ-ray emissions under the SSC radiation exhibits an almost linear relationship, which may serve as a tool to differentiate radiation mechanisms. We anticipate future statistical analyses of additional VHE bursts to validate our findings.

关键词： (transients:) gamma-ray bursts gamma-rays: ISM radiation mechanisms: non-thermal

非匹配条件下非线性系统的指定时间二阶滑模控制

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控制与决策 2024年第9期39卷 3043-3051页

作者：石尚张国胜闵惠芳河海大学能源与电气学院南京211100 东南大学自动化学院南京210096 南京理工大学自动化学院南京210094

针对不确定非线性系统设计一种新型指定时间二阶滑模(SOSM)控制器.首先,通过选取新的滑模变量,将标准的二阶滑模积分链系统推广至带有非匹配项的新二阶滑模动态系统,新滑模动态系统的使用可以有效减少传统滑模系统控制通道中的不确定性... 详细信息

针对不确定非线性系统设计一种新型指定时间二阶滑模(SOSM)控制器.首先,通过选取新的滑模变量,将标准的二阶滑模积分链系统推广至带有非匹配项的新二阶滑模动态系统,新滑模动态系统的使用可以有效减少传统滑模系统控制通道中的不确定性;其次,通过使用时变放缩函数的概念,在非匹配项的增益函数上界未知的情况下,针对新的滑模动态系统提出一种基于切换策略的指定时间SOSM控制算法.所提出的控制器从一个有限时间域的SOSM控制器切换到传统的有限时间SOSM控制器,前者可以保证滑模变量在有限时间域内实现指定时间收敛到零,且收敛时间不依赖于系统的初始条件;后者可以保证滑模变量此后始终保持在零.最后,对闭环系统的指定时间稳定性进行了分析,通过仿真对比验证了理论结果的有效性.

关键词：指定时间控制二阶滑模非线性系统非匹配项滑模控制不确定系统

不确定Chua电路系统的固定时间自适应参数估计

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控制理论与应用 2022年第8期39卷 1551-1560页

作者：石尚李慧闵惠芳徐胜元孙永辉河海大学能源与电气学院江苏南京211100 南京理工大学自动化学院江苏南京210094 东南大学自动化学院江苏南京234299

针对具有未知参数的不确定Chua电路系统,本文提出了一种基于Volterra积分算子的固定时间自适应参数估计算法.在仅有输出信号的已知的情况下,该算法能够保证参数的估计值在一个不依赖于初始误差的固定时间内收敛到参数的真实值.通过在Vol... 详细信息

针对具有未知参数的不确定Chua电路系统,本文提出了一种基于Volterra积分算子的固定时间自适应参数估计算法.在仅有输出信号的已知的情况下,该算法能够保证参数的估计值在一个不依赖于初始误差的固定时间内收敛到参数的真实值.通过在Volterra积分算子中巧妙的选取核函数,使其满足在τ=0和τ=t时核函数及其导数为零,从而能够有效消除系统初始值的影响,同时避免了对系统输出导数的计算.最后,仿真结果验证了所提算法的有效性.

关键词： Chua电路固定时间自适应参数估计 Volterra积分算子

Galileo multi-day precise orbit determination using L-band and SLR data

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Geodesy and Geodynamics 2025年第1期16卷 99-110页

作者： Tianhe Xu Honglei Yang Song Li Zhenlong fang Wenfeng Nie min Li Baoguo Yu Shandong Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment Institute of Space Sciences Shandong University Navigation Laboratory of the 54th Research Institute of China Electronics Technology Group Corporation

The continuously available satellites of European Galileo currently reach more than 25. To explore the rationality and reliability of the L-band and satellite laser ranging(SLR) data processing strategies, we design the Galileo L-band, the SLR-only, and the combined L-band/SLR dynamic precise orbit determination(POD) strategies by using the normal equations(NEQs) stacking, and investigate their continuity and stability by employing the Galileo L-band data and SLR observations for the time span of the whole year of 2023, based on the Bei Dou/GNSS analysis center platform of Shandong University by using the modified Bernese GNSS Software Version 5.4. The orbital consistency of the L-band 1-day solution is the best with the Three-dimensional Root-Mean-Square(3D-RMS) values of 3.6 cm compared with the Center for Orbit Determination in Europe Multi-GNSS Experiment(COM) orbits, the corresponding values is 1.4 cm, 2.5 cm, and 2.3 cm in Radial, the Tangential, and the Normal(RTN) direction, respectively. While the SLR-only 9-day arc length is optimal with the RTN values of 5.3 cm, 30 cm, and 38.2 cm,as well as the 3D-RMS values of 48.9 cm. Encouragingly, the difference of the orbital accuracy between the combined L-band/SLR multi-day solution and the COM orbits is reduced by 0.5 cm and 0.9 cm, 0.6 cm and 1.2 cm in T-, and N-direction for the 3-and 5-day solution respectively. The corresponding values improve 0.7 cm and 0.9 cm, 1.4 cm and 1.8 cm for the 3-and 5-day orbital overlaps difference between the combined L-band/SLR and the L-band solution. Take the E09 satellite as a case study, the SLR-only orbital accuracy is regularly optimized as the multi-day arc lengthens and with the sites ***, the SLR residuals of its three types of orbits further demonstrate the positive contribution of SLR to the combination of the GNSS and SLR techniques.

关键词： Galileo POD SLR L-band NEQs stacking

In situ seed layer bandgap engineering leading to the conduction band offset reversion and efficient Sb2Se3 solar cells with high open-circuit voltage

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Journal of Energy Chemistry 2025年第2期101卷 201-212页

作者： Yanting Jiang Weiyu Wang Zhirong Chen Zhenyu fang Qiqiang Zhu Qiao Zheng Jionghua Wu hui Deng Weihuang Wang Shuying Cheng Fuzhou University Institute of Micronano Devices & Solar Cells College of Physics & Information Engineering Jiangsu Collaborative Innovation Center for Photovoltaic Science and Engineering

Sb2Se3solar cells have achieved a power conversion efficiency（PCE） of over 10%.However,the serious open-circuit voltage deficit(VOC-deificit),induced by the hard-to-control crystal orientation and heterojunction interface reaction,limits the PCE of vapor transport deposition（VTD） processed Sb2Se3solar *** overcome the VOC-deficit problem of VTD processed Sb2Se3solar cells,herein,an in-situ bandgap regulation strategy is innovatively proposed to prepare a wide band gap Sb2（S,Se）3seed layer（WBSL） at CdS/Sb2Se3heterojunction interface to improve the PCE of Sb2Se3solar *** analysis results show that the introduced Sb2（S,Se）3seed layer can enhance the [001] orientation of Sb2Se3thin films,broaden the band gap of heterojunction interface,and realize a "Spike-like" conduction band alignment withΔEc=0.11 *** addition,thanks to the suppressed CdS/Sb2Se3interface reaction after WBSL application,the depletion region width of Sb2Se3solar cells is widened,and the quality of CdS/Sb2Se3interface and the carrier transporting performance of Sb2Se3solar cells are significantly improved as ***,the harmful Se vacancy defects near the front interface of Sb2Se3solar cells can be greatly diminished by ***,the PCE of Sb2Se3solar cells is improved from 7.0% to 7.6%;meanwhile the VOCis increased to 466 mV which is the highest value for the VTD derived Sb2Se3solar *** work will provide a valuable reference for the interface and orientation regulation of antimony-based chalcogenide solar cells.

关键词： Band gap alignment Carrier transport Crystal orientation Open circuit voltage deficit Seed-layer