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arXiv 2025年

作者： Li, Jialu Han, Xue Wang, Wenjie Wang, Jinhui Zhang, Tingting Wu, Yuting Zhang, Guofeng Li, Bin Yang, Changgang Guo, Wenli Zhang, Mi Chen, Ruiyun Qin, Chengbing Hu, Jianyong Yang, Zhichun Liu, Shaoding Wang, Yue Gao, Yunan Ma, Jie Xiao, Liantuan Jia, Suotang State Key Laboratory of Quantum Optics Technologies and Devices Institute of Laser Spectroscopy Collaborative Innovation Center of Extreme Optics Shanxi University Taiyuan030006 China Key Lab of Advanced Transducers and Intelligent Control System of Ministry of Education Taiyuan University of Technology 79 Yingze Street Taiyuan030024 China School of Microelectronics College of Materials Science and Engineering Nanjing University of Science and Technology Nanjing210094 China State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics School of Physics Peking University Beijing100871 China

Colloidal quantum dots (QDs) are promising optical gain materials that require further threshold reduction to realize their full potential. While QD charging theoretically reduces the threshold to zero, its effectiveness has been limited by strong Auger recombination and unstable charging. Here we theoretically reveal the optimal combination of charging number and Auger recombination to minimize the lasing threshold. Experimentally, we develop stable self-charged perovskite quantum rods (QRs) as an alternative to QDs via state engineering and Mn-doping strategy. An unprecedented two-order-of-magnitude reduction in nonradiative Auger recombination enables QRs to support a sufficient charging number of up to 6. The QR liquid lasing is then achieved with a near-zero threshold of 0.098 using quasi-continuous pumping of nanosecond pulses, which is the lowest threshold among all reported QD lasers. These achievements demonstrate the potential of the specially engineered QRs as an excellent gain media and pave the way for their prospective applications. Copyright © 2025, The Authors. All rights reserved.

关键词： Optical pumping

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NURBS Interpolator With Pre-compensation Based on Discrete Inverse Transfer Function for CNC High-precision Machining

Research Square

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Research Square 2021年

作者： Wang, Taiyong Cao, Libo Zhang, Yongbin Dong, Jingchuan Jia, Songhui Tian, Chong Liu, Qingjian Renai College Tianjin University Tianjin301636 China Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin300384 China School of Mechanical Engineering Tianjin University No.135 YaGuan Road Jinnan District Tianjin300354 China

In the field of CNC machining, high-speed and high-precision machining has been regarded as the key research by many scholars. In conventional methods, high-speed machining and high-precision machining are contradictory. It is inevitable to reduce the feedrate to improve the processing accuracy. In the paper, a pre-compensation based on discrete inverse transfer function (PDIT) theory is proposed. PDIT is able to improve machining accuracy by reducing contour errors without decreasing feedrate. The proposed PDIT theory is divided into three parts, NURBS interpolator, feedrate scheduling, and interpolator with pre-compensation. The NURBS interpolator has greatly advantage to interpolate the parameter curve directly. Therefore, the paper adopts the NURBS interpolator to accomplish interpolation. In the feedrate scheduling, S-type flexible acceleration and deceleration are used for path planning, and the maximum starting feedrate is obtained with the feedrate constraint. In the interpolator with pre-compensation, the NURBS interpolator is pre-compensated by PDIT. For inputs, the response of transfer function reach steady-state response with a little time. Before reaching steady-state response, the unsteady response exists in the transfer function. The unsteady response usually sustains tens of interpolation periods and must be lead contour error in machining. Hence, the PDIT theory is employed to compensate the contour error causing by the unsteady response of transfer function to NURBS interpolator. The drive system is a transfer function, so the unsteady response of drive system cause machining errors before reaching the steady-state response. In the paper, the NURBS interpolator is pre-compensated by PDIT theory before the drive system to reduce contour errors and improve machining accuracy. Finally, the performance of the proposed PDIT is evaluated by simulation experiments. The experimental results illustrate that PDIT theory obviously improve the machining accura

关键词： Transfer functions

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Multi-objective Dimensional Optimization of a 3-DOF Translational PKM Considering Transmission Properties

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International Journal of Automation and computing 2019年第6期16卷 748-760页

作者： Song Lu Yang-Min Li Bing-Xiao Ding Department of Electromechanical Engineering University of MacaoTaipaMacao 853China Department of Industrial and Systems Engineering The Hong Kong Polytechnic UniversityKowloonHong Kong 852China Tianjin Key Laboratory of the Design and Intelligent Control of the Advanced Mechatronical System Tianjin University of TechnologyTianjin 300384China

Multi-objective dimensional optimization of parallel kinematic manipulators(PKMs) remains a challenging and worthwhile research endeavor. This paper presents a straightforward and systematic methodology for implementing the structure optimization analysis of a 3-prismatic-universal-universal(PUU) PKM when simultaneously considering motion transmission, velocity transmission and acceleration transmission. Firstly, inspired by a planar four-bar linkage mechanism, the motion transmission index of the spatial parallel manipulator is based on transmission angle which is defined as the pressure angle amongst limbs. Then, the velocity transmission index and acceleration transmission index are derived through the corresponding kinematics model. The multi-objective dimensional optimization under specific constraints is carried out by the improved non-dominated sorting genetic algorithm(NSGA Ⅱ), resulting in a set of Pareto optimal solutions. The final chosen solution shows that the manipulator with the optimized structure parameters can provide excellent motion, velocity and acceleration transmission properties.

关键词： Multi-objective optimization parallel kinematic manipulator transmission property non-dominated sorting genetic algorithm(NSGA Ⅱ)

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Non-reciprocity of energy transfer derived from cubic stiffness-induced nonlinear phenomena

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Results in Physics 2025年 73卷

作者： Kong, Na Sun, Min Chen, Jianen Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin 300384 China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology Tianjin 300384 China School of Science Tianjin Chengjian University Tianjin 300384 China

Introducing purely nonlinear elastic elements can induce rich dynamic behaviors, such as bifurcations, jumps and isolated resonance curves, to linear systems. Therefore, these elements are suitable for constructing strong non-reciprocity of vibration energy transfer. First, the energy transfer along reciprocal directions in a three-degree-of-freedom system is investigated, where three oscillators are connected by cubic springs. The semi-analytical solutions of the system are obtained using the complexification-averaging method and the least squares method. The results are compared against numerical solutions obtained by the Runge-Kutta method. The excitation amplitude range that produces strong non-reciprocity of vibration energy is analyzed. The jump phenomenon under combined excitation is investigated, and a trigger method for constructing non-reciprocity using an impulse is proposed. Then, an oscillator chain with cubic stiffness and scaling parameters is embedded into a multi-degree-of-freedom linear oscillator system to further explore the effect of cubic stiffness. Energy transfer along two directions is compared by exciting the leftmost oscillator and the rightmost oscillator. Moreover, the trigger effect of the impulse on non-reciprocity is demonstrated. The results show significant differences in vibration energy transfer within three distinct frequency bands. The critical points between reciprocal and non-reciprocal states are obtained, and the three stages of reciprocity related to excitation amplitude are analyzed. Lastly, the modulation effect of the cubic stiffness on non-reciprocity is conducted by comparing the energy of the output oscillator. © 2025 The Authors

关键词： Cubic stiffness Energy transfer Jump phenomenon Non-reciprocity

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Global Dynamics and Optimal Design of a New Highly Efficient Nonlinear Energy Sink Based on Magnetic-Elastic Impacts with Negative Stiffness

Research Square

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Research Square 2021年

作者： Li, Shuangbao Wang, Tingting Chen, Jianen Research Institute of Science and Technology Innovation Civil Aviation University of China Tianjin300300 China College of Science Civil Aviation University of China Tianjin300300 China Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin300384 China

A new highly efficient elastic-impact bistable nonlinear energy sink (EI-BNES) based on magnetic-elastic impacts with negative stiffness and bistability is proposed and optimized through global dynamical analysis. The EI-BNES has better robustness and higher energy dissipation rates with nearly more than 96.5% for broadband impulsive excitations than the traditional cubic NESs and single bistable NESs. The structure of negative stiffness impacts is realized by reasonable layout of permanent ring magnets and springs. A two-degree-of-freedom (two-DOF) elastic-impact system is established to describe the coupled nonlinear interaction between the main structure and the attached EI-BNES. A global Melnikov reduction analysis (GMRA) is proposed to study global dynamics and homoclinic bifurcations of the reduced two-dimensional subsystem, which is used to explain the mechanism of nonlinear targeted energy transfer (TET) and detect the threshold of impulsive amplitudes of EI-BNES for in-well and compound motions between in-well and cross-well resonance responses. A special type of saddle-center equilibrium points is also found in the non-smooth system of the EI-BNES and can be used to effectively increase the energy dissipation rates. The optimal design criterion of the tuned EI-BNES for better dissipation performance is also first discussed based on the GMRA and numerical techniques for calculating the Melnikov function of the non-smooth systems. The effectiveness of the analytical GMRA is also verified by numerical simulations. © 2021, CC BY.

关键词： Stiffness

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An Efficiency Enhanced Graphene/n-Si Schottky Junction for Solar Cells

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Chinese Physics Letters 2018年第7期35卷 58-61页

作者：李刚程宏伟郭丽芳王开鹰程再军 MicroNano System Research Center College of Information and Computer & Key Lab of Advanced Transducers and Intelligent Control System of Ministry of Education Taiyuan University of Technology Taiyuan 030024 School of Optoelectronic and Communication Engineering Xiamen University of Technology Xiamen 361024

A novel and facile oxidation-induced self-doping process of graphene-silicon Schottky junction by nitric acid（HNO3） vapor is reported. The HNO3 oxidation process makes graphene p-type self-doped, and leads to a higher built-in potential and conductivity to enhance charge transfer and to suppress charge carrier recombination at the graphene-silicon Schottky junction. After the HNO3 oxidation process, the open-circuit voltage is increased from the initial value of 0.36 V to the maximum value of 0.47 V, the short-circuit current is greatly increased from 0.80μA to 7.71μA, and the ideality factor is optimized from 4.4 to 1.0. The enhancement of the performance of graphene-Si solar cells may be due to oxidation-induced p-type self-doping of graphene-Si junctions.

关键词： Graphene

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Life-detection radar based on wideband chaotic signal

Life-detection radar based on wideband chaotic signal

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IET International Radar Conference 2018, IRC 2018

作者： Xu, Hang Li, Ying Li, Liqiang Zhang, Jianguo Han, Hong Liu, Li Wang, Bingjie Key Laboratory of Advanced Transducers and Intelligent Control System Ministry of Education and Shanxi Province Taiyuan University of Technology No. 79 Yingze West Main Street Taiyuan China College of Physics and Optoelectronics Taiyuan University of Technology No. 79 Yingze West Main Street Taiyuan China

We propose a novel life-detection radar using a wideband Boolean-chaos signal as a probe signal. The range between the radar and the human target can be obtained by correlating the echo signal from the target with its delayed duplicate. This range is modulated periodically by human chest's displacements along the recording time axis and the modulation frequency is the same as the respiratory frequency. Therefore, the authors propose a life-detection algorithm based on correlation method to detect the human target's respiratory frequency and range. Experimental results demonstrate that the authors' radar can simultaneously detect the respiratory frequency and range of the human target behind a 20-cm-thick wall. In addition, the high range resolution and excellent anti-jamming property of the chaotic radar have been demonstrated by their previous studies, which make it perform superbly in complex electromagnetic environments. © 2019 Institution of Engineering and Technology. All rights reserved.

关键词： Tracking radar

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Distribution of Dislocation-Twin Interaction in Twip Steel Under Different Loading Modes

SSRN

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SSRN 2022年

作者： Guo, Xiangru Mao, Ningdong Sun, Chaoyang Wang, Chunhui Cui, Yinan Xiong, Zhiping Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin300384 China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology Tianjin300384 China School of Mechanical Engineering University of Science and Technology Beijing Beijing100083 China Applied Mechanics Lab School of Aerospace Engineering Tsinghua University Beijing100084 China National Key Laboratory of Science and Technology on Materials under Shock and Impact Beijing Institute of Technology Beijing100081 China

The tension-compression asymmetry and orientation effect of dislocation-twin boundary (TB) interactions in twinned TWIP steels were investigated using the discrete dislocation dynamics simulations and Schmid's law. The different types of dislocations dominate the TB migration in the twinned TWIP steel during tension and compression with the same loading orientation, and the asymmetric dislocation reactions at TB were attributed to the different leading partials produced after the dissociation of dislocation under different loading modes (tension or compression). Moreover, the complex dislocation-TB interactions, such as dislocations traversing TB, cross slip, dissociation, pile up and so on, were determined by considering the orientation effect of dislocation activation and the asymmetry of dislocation dissociation. The research advances the understanding of asymmetric behavior of twin and its influence on the macro hardening in plastic deformation of TWIP steels. © 2022, The Authors. All rights reserved.

关键词： Dissociation

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Research on Crack Detection of Nonlinear Rotor Based on Energy Tracks

Research on Crack Detection of Nonlinear Rotor Based on Ener...

引用

IEEE International Conference on Mechatronics and Automation

作者： Yu Zhang Jun Liu Zhu Han Tianjin Key Laboratory for Advanced Mechanical System Design and Intelligent Control Tianjin University of Technology Tianjin China National Demonstration Centre for Experimental Mechanical and Electrical Engineering Education Tianjin University of technology

ISBN: (数字)9781728164168

ISBN: (纸本)9781728164175

In rotating machinery, because of high-speed working characteristics and terrible working conditions with variable cycles and variable loads, it is easy for rotors to cause a crack initiation and propagation, which may cause serious harm or even the life-threatening. The super harmonic component is an important role of the crack detection. But it is difficult to reflect the super harmonic component in the high-speed region after super harmonic resonances. In this paper, the dynamic equation of a nonlinear rotor system with a crack is considered, the potential energy expression of the cracked rotor is derived, and the concept of energy tracks is proposed. In the distortion of energy tracks, the effects of different crack parameters and nonlinear parameters on the vibration characteristics of the rotor system are compared. The results show that the energy trajectory distortion can diagnose the crack fault. It provides a new research method for vibration response analyses and fault diagnoses of cracked rotor system.

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Research on Asymmetrical Dual-rotor system Based on the Energy Orbit

Research on Asymmetrical Dual-rotor System Based on the Ener...

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IEEE International Conference on Mechatronics and Automation

作者： Zhu Han Jun Liu Yu Zhang Tianjin Key Laboratory for Advanced Mechanical System Design and Intelligent Control Tianjin University of Technology Tianjin China National Demonstration Centre for Experimental Mechanical and Electrical Engineering Education Tianjin University of technology

ISBN: (数字)9781728164168

ISBN: (纸本)9781728164175

Studying the vibration of asymmetrical dual-rotor is very important for aero engines. In this paper, based on the vibration characteristics of an aero-engine, a different novel coupled dynamic model is proposed based on the spring recovery characteristics of rotor. The model dynamic equations of asymmetrical dual-rotor are obtained by the Lagrange equation, and vibration resonance curves of high pressure and low pressure rotors are numerically simulated and theoretically analyzed by using the Runge-Kutta algorithm. The research show that the system occurs combined vibration, harmonic vibration and superharmonic vibration. In addition, the vibration occurring mechanism was investigated and verified in detail through numerical simulation. For the first time, the concept of energy orbit was introduced into the dual-rotor model system. The energy orbit represents the vibration characteristics and energy exchange process of the model system. Energy orbit is a new energy orbit method for analyzing vibration characteristics of rotor system. The new researches of this paper will show a different research direction for complex dual-rotor systems.

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