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Revolutionizing solid-state single-photon sources with multifunctional metalenses

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Light(Science & Applications) 2024年第1期13卷 8-9页

作者： Fei ding Centre for Nano Optics University of Southern DenmarkCampusvej 55Odense MDK-5230Denmark

Ultrathin multifunctional metalenses are demonstrated to control the multiple degrees of freedom of a single-photon source in hexagonal boron nitride.

关键词： hexagonal boron state

Steady-state responses of a belt-drive dynamical system under dual excitations

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Acta Mechanica Sinica 2016年第1期32卷 156-169页

作者： Hu ding Shanghai Institute of Applied Mathematics and Mechanics Shanghai Key Laboratory of Mechanics in Energy EngineeringShanghai UniversityShanghai 200072China

The stable steady-state periodic responses of a belt-drive system with a one-way clutch are studied. For the first time, the dynamical system is investigated under dual excitations. The system is simultaneously excited by the firing pulsations of the engine and the harmonic motion of the foundation. Nonlinear discrete-continuous equations are derived for coupling the transverse vibration of the belt spans and the rotations of the driving and driven pulleys and the accessory pulley. The nonlinear dynamics is studied under equal and multiple relations between the frequency of the fir- ing pulsations and the frequency of the foundation motion. Furthermore, translating belt spans are modeled as axially moving strings. A set of nonlinear piecewise ordinary differ- ential equations is achieved by using the Galerkin truncation. Under various relations between the excitation frequencies, the time histories of the dynamical system are numerically simulated based on the time discretization method. Further- more, the stable steady-state periodic response curves are calculated based on the frequency sweep. Moreover, the convergence of the Galerkin truncation is examined. Numer- ical results demonstrate that the one-way clutch reduces the resonance amplitude of the rotations of the driven pul- ley and the accessory pulley. On the other hand, numerical examples prove that the resonance areas of the belt spans are decreased by eliminating the torque-transmitting in the opposite direction. With the increasing amplitude of the foun- dation excitation, the damping effect of the one-way clutch will be reduced. Furthermore, as the amplitude of the firing pulsations of the engine increases, the jumping phenomena in steady-state response curves of the belt-drive system with or without a one-way clutch both occur.

关键词： Nonlinear vibration One-way clutch Dynamical system Steady-state responses Galerkinmethod

Biodegradation of jute/poly(lactic acid) composites by fungi

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Science China(Technological Sciences) 2018年第11期61卷 1705-1712页

作者： ding ding YU Tao LI Yan School of Aerospace Engineering and Applied Mechanical Tongji University State Key Laboratory for Strength and Vibration of Mechanical Structures Xi'an Jiaotong University Key Laboratory of Advanced Civil Engineering Materials Ministry of Education Tongji University

Jute/poly(lactic acid)(PLA) composites were firstly prepared by extrusion and injection molding. Then the composites were exposed to a fungi environment for 28 d which consisted with five fungi according to the American Society of Testing Materials(ASTM) standards. Weight loss, morphology and mechanical properties of the samples with different infected days were measured. Gel permeation chromatography(GPC), scanning electron microscope(SEM) and differential scanning calorimetry(DSC) were utilized to analyze the infected process. Mechanism can be concluded that PLA on the surface of composites slowly degraded under the fungi environment. Then surface fiber were exposed in the air, the interface gap between fiber and matrix enlarged, resulting in the decline of the mechanical properties.

关键词： jute poly(lactic acid) composites biodegradation fungi

2D phosphides heterostructures on titanium microfiltration membrane for enhanced ampere-level current density overall seawater splitting

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Nano Research 2025年第1期18卷 249-259页

作者： Wenjing Dai Xin Wang Yulong Ma Sisi He Ming Chen Zhaohui Yin Shuheng Tian Maolin Wang Shixiang Yu Hang Zhang Yuanzhe Wang Hong Wang Jianxin Li Faming Gao Bowen Cheng Yun Wang Zhen Yin ding Ma Tianjin Key Laboratory of Brine Chemical Engineering and Resource Eco-utilization College of Chemical Engineering and Materials ScienceTianjin University of Science and TechnologyTianjin 300457China State Key Laboratory of Biobased Fiber Manufacturing Technology Tianjin University of Science and TechnologyTianjin 300457China Haian Institute of High-Tech Research Nanjing UniversityHaian 226600China Beijing National Laboratory for Molecular Sciences College of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China State Key Laboratory of Separation Membranes and Membrane Processes Separation Membrane Science and Technology International Joint Research CentreTiangong UniversityTianjin 300387China Centre for Catalysis and Clean Energy School of Environment and ScienceGold Coast CampusGriffith UniversitySouthportQueensland 4222Australia

The advancement of direct seawater electrolysis is a significant step towards sustainable hydrogen production,addressing the critical need for renewable energy sources and efficient resource ***,direct seawater electrolysis has to face several challenges posed by the corrosiveness of highly concentrated chloride and the competitive chlorine evolution reaction(ClER).To overcome these issues,we designed a novel NiP_(2)@CoP electrocatalyst on a porous titanium microfiltration(Ti MF)*** obtained bifunctional NiP_(2)@CoP catalyst outperforms the Pt/C and IrO_(2),as evidenced by its low overpotentials of 192 and 425 mV at a current density of 500 mA·cm^(-2) for hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)in alkaline seawater(1 M KOH+0.5 M NaCl),***,only 231 and 569 mV overpotentials are required at the current density of 1500 mA·cm^(-2) towards HER and OER in alkaline seawater,*** importantly,no ClER was observed,demonstrating its excellent selectivity to *** selection of porous Ti MF membrane as an electrode substrate further enhances the performance by providing a robust structure that promotes the fast generation and release of gas *** promising outcomes obtained with NiP_(2)@CoP catalysts on Ti MF support,therefore,pave the way for the commercial viability of direct seawater electrolysis technologies at industrial-level current densities.

关键词： direct seawater electrolysis porous titanium microfiltration membrane phosphides heterostructures NiP_(2)@CoP electrocatalyst excellent selectivity to oxygen evolution reaction(OER)

Smoothness-oriented path optimization for robotic milling processes

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Science China(Technological Sciences) 2020年第9期63卷 1751-1763页

作者： PENG JingFu ding Ye ZHANG Gang ding Han State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong UniversityShanghai200240China HUST-Wuxi Research Institute Wuxi214174China

Industrial robots are increasingly used for five-axis machining operations, where the rotation of the end effector along the toolaxis direction is functionally redundant. This functional redundancy should be carefully resolved when planning the robot path according to the tool path generated by a computer-aided manufacturing(CAM) system. Improper planning of the redundancy may cause drastic variations of the joint motions, which could significantly decrease the machining efficiency as well as the machining accuracy. To tackle this problem, this paper presents a new optimization-based methodology to globally resolve the functional redundancy for the robotic milling process. Firstly, a global performance index concerning the smoothness of the robot path at the joint acceleration level is proposed. By minimizing the smoothness performance index while considering the avoidance of joint limits and the singularity and the constraint of the stiffness performance, the resolution of the redundancy is formulated as a constrained optimization problem. To efficiently solve the problem, the sequential linearization programming method is employed to improve the initial solution provided by the conventional graph-based method. Then, simulations for a given tool path are presented. Compared with the graph-based method, the proposed method can generate a smoother robot path in which a significant reduction of the magnitude of the maximum joint acceleration is obtained, resulting in a smoother tool-tip feedrate profile. Finally, the experiment on the robotic milling system is also presented. The results show that the optimized robot path of the proposed method obtains better surface quality and higher machining efficiency, which verifies the effectiveness of the proposed method.

关键词： robot milling functional redundancy path optimization smoothness sequential linear programming

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

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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

Possible effects of selecting different station distributions in the optimal sequence estimation method

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Geodesy and Geodynamics 2024年第6期15卷 554-567页

作者： Hao ding School of Geodesy and Geomatics Hubei Luojia LaboratoryWuhan UniversityWuhan 430079China

Since the inception of the optimal sequence estimation (OSE) method,various research teams have substantiated its efficacy as the optimal stacking technique for handling array data,leading to its successful application in numerous geoscience ***,concerns persist regarding the potential impact of aliasing resulting from the choice of distinct station distributions on the outcomes derived from *** this investigation,I employ theoretical deduction and experimental analysis to elucidate the reasons behind the immunity of the Y_(l'm')-related common signal obtained through OSE to variations in station distribution *** primary objective of OSE is also underscored,i.e.,to restore/strip a Y_(l'm')-related common periodic signal from various ***,I provide additional clarification that the‘Y_(l'm')-related common signal’and the‘Y_(l'm')-related equivalent excitation sequence’are distinct *** analyses will facilitate the utilization of the OSE technique by other researchers in investigating intriguing geophysical phenomena and attaining sound explanations.

关键词： Optimal sequence estimation Station selection GPS

Secure separable reversible data hiding of halftone image in blockchain

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The Journal of China Universities of Posts and Telecommunications 2022年第2期29卷 85-96页

作者： ding Haiyang College of Information Engineering Beijing Institute of Graphic CommunicationBeijing 102600China Information Security Center Beijing University of Posts and TelecommunicationsBeijing 100876China

To realize the distributed storage and management of a secret halftone image in blockchain,a secure separable reversible data hiding(RDH)of halftone image in blockchain(SSRDHB)was proposed.A secret halftone image can be used as the original image to generate multiple share images which can be distributed storage in each point of blockchain,and additional data can be hidden to achieve management of each share ***,the secret halftone image was encrypted through Zu Chongzhi(ZUC)algorithm by using the encryption key(EK).Secondly,the method of using odd or even of share data was proposed to hide data,and a share dataset can be generated by using polynomial ***,multiple share images can be obtained through selecting share data,and different additional data can be hidden through controlling odd or even of share data,and additional data can be protected by using data-hiding key(DK).After sharing process,if the receiver has both keys,the halftone image can be recovered and additional data can be revealed,and two processes are *** results show that multiple share images hidden additional data can be obtained through SSRDHB,and the halftone image can be recovered with 100%by picking any part of share images,and one additional data can be revealed with 100%by picking any one share image.

关键词： separable reversible data hiding(RDH) halftone image secret sharing blockchain additional data

Global Stability of Multi-wave Configurations for the Compressible Non-isentropic Euler System

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Chinese Annals of Mathematics,Series B 2021年第6期42卷 921-952页

作者： Min ding Department of Mathematics School of ScienceWuhan University of TechnologyWuhan 430070China

This paper is contributed to the structural stability of multi-wave configurations to Cauchy problem for the compressible non-isentropic Euler system with adiabatic exponentγ∈(1,3].Given some small BV perturbations of the initial state,the author employs a modified wave front tracking method,constructs a new Glimm functional,and proves its monotone decreasing based on the possible local wave interaction estimates,then establishes the global stability of the multi-wave configurations,consisting of a strong 1-shock wave,a strong 2-contact discontinuity,and a strong 3-shock wave,without restrictions on their strengths.

关键词： Structural stability Multi-wave configuration Shock Contact discontinuity Compressible non-isentropic Euler system Wave front tracking method