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Coordinated optimization of signal timing for intersections with dynamic shared through-and right-turn lanes

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Journal of Intelligent and Connected Vehicles 2024年第3期7卷 219-228页

作者： zhe zheng Jian Yuan Kun An Nan zheng Wanjing Ma The Key Laboratory of Road and Traffic Engineering Ministry of EducationTongji UniversityShanghai 201804China Department of Civil Engineering Monash UniversityMelbourne VIC 3800Australia

Through and right-turn shared lanes are widely designed to increase the capacity of through traffic,but they can also cause delays for right-turn *** study presents a dynamic control method for a shared lane that prioritizes right-turn vehicles at the beginning of the cycle and subsequently allows through traffic to queue in the shared lane for saturated *** traffic wave model is employed to reveal the dynamics of the traffic flow under this control and to derive the relationships among major traffic *** by the major relationship,a linear programming approach to minimize the total queue length is developed to determine the proper values of control parameters,including the shared area length,subordinate signal time lag,and shared or exclusive duration.A sensitivity analysis of the control parameters for different arrival rates and flow ratios is *** are conducted among the dynamic shared lane,the fixed exclusive lane,and the fixed shared *** results show that the dynamic control method results in a lower delay for both through and total traffic.

关键词： traffic control dynamic lane right-turn traffic optimization model

Association between cardiovascular implantable electronic devices and tricuspid regurgitation: a case- control study

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World Journal of Emergency Medicine 2022年第5期13卷 403-405页

作者： Yuan-yuan Zhang Yan Cheng Liang-rong zheng zhe-lan zheng Department of Cardiovascular Ultrasonic Center the First Affi liated HospitalZhejiang University School of MedicineHangzhou 310003China Department of Cardiology the First Affi liated HospitalZhejiang University School of MedicineHangzhou 310003China

Cardiovascular implantable electronic devices(CIEDs)are widely used in the modern *** year,about 730,000 permanent pacemakers and 330,000 CIEDs are implanted *** have been known to increase the life expectancy of millions of people and improve their quality of life by controlling the heart rate and atrioventricular and interventricular synchronization and preventing sudden cardiac death.[1]The tricuspid valve consists of the annulus,leaflets,chordae tendineae,and papillary *** between the endocardial lead and any component of this structure can lead to tricuspid valve dysfunction,thereby resulting in tricuspid regurgitation(TR).[2]CIED-related TR has been shown to be an independent predictor of hospitalization for heart failure.[3,4]

关键词： tricuspid regurgitation ventricular

Analytical Analysis and Performance Characterization of Brushless Doubly Fed Induction Machines Based on General Air-gap Field Modulation Theory

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Chinese Journal of Electrical Engineering 2021年第3期7卷 4-19页

作者： Peng Han ming Cheng Xinkai Zhu zhe Chen Ansys Inc.San JoseCA 95134USA School of Electrical Engineering Southeast UniversityNanjing 210096China Department of Electrical Engineering North China Electric Power UniversityBaoding 071003China Department of Energy Technology Aalborg UniversityAalborg 9220Denmark

Air-gap magnetic field modulation has been widely observed in electric *** this study,we present an analytical analysis and performance characterization of brushless doubly fed induction machines(BDFIMs)fed by two independent converters from the perspective of air-gap field *** spiral-loop winding is studied in detail as an example to show the generalized workflow that can also be used to analyze other short-circuited rotor winding types,such as nested-loop and multiphase double-layer *** field conversion factors are introduced to characterize the modulation behavior of special rotor windings and facilitate their comparison in terms of cross-coupling capability,average torque,and harmonic content of the air-gap flux density *** stator magnetomotive force(MMF),rotor MMF,and resultant air-gap MMF are considered,based on which the closed-form inductance formulas are derived,and the torque equation is obtained along with the optimal current angle for maximum torque operation by using the virtual work *** design equations are then developed for the initial sizing and geometry scaling of the *** finite element analysis and experimental measurements are performed to validate the analysis.

关键词： AC machines air gap magnetic field spatial harmonic frequency domain modulation rotor windings

Mechanical buckling induced periodic kinking/stripe microstructures in mechanically peeled graphite fla es from HOPG

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Acta Mechanica Sinica 2015年第4期31卷 494-499页

作者： Manrui Ren Ze Liu Quan-shui zheng Jefferson zhe Liu Department of Engineering Mechanics and Center for Nano and Micro Mechanics Tsinghua University Department of Mechanical and Aerospace Engineering Monash University

Mechanical exfoliation is a widely used method to isolate high quality graphene layers from bulk graphite. In our recent experiments, some ordered microstructures, consisting of a periodic alternation of kinks and stripes, were observed in thin graphite flakes that were mechanically peeled from highly oriented pyrolytic graphite. In this paper, a theoretical model is presented to attribute the formation of such ordered structures to the alternation of two mechanical processes during the exfoliation：（1） peeling of a graphite flake and （2） mechanical buckling of the flake being sub- jected to bending. In this model, the width of the stripes L is determined by thickness h of the flakes, surface energy Y, and critical buckling strain ecr. Using some appropriate values of y and ecr that are within the ranges determined by other inde- pendent experiments and simulations, the predicted relations between the stripe width and the flake thickness agree reason- ably well with our experimental measurements. Conversely, measuring the L-h relations of the periodic microstructures in thin graphite flakes could help determine the critical mechan- ical buckling strain εcr and the interface energy γ.

关键词： HOPG Mechanical exfoliation Periodic microstructures Kinking Mechanical buckling

Influence of substrate metals on the crystal growth of AlN films

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International Journal of Minerals,Metallurgy and Materials 2010年第1期17卷 98-103页

作者： Juan Xiong Hao-shuang Gu Kuan Hu ming-zhe Hu School of Physics and Electronic Technology Hubei University Wuhan 430062 China

AlN films were deposited by reactive radio frequency （RF） sputtering on various bottom electrodes, such as Al, Ti, Mo, Au/Ti, and Pt/Ti. The effects of substrate metals on the orientation of AlN thin films were investigated. The results of X-ray diffraction, atomic force microscopy, and field emission scanning electron microscopy show that the orientation of AlN films depends on the kinds of substrate metals evidently. The differences of AlN films deposited on various metal electrodes are attributed to the differences in lattice mismatch and thermal expansion coefficient between the AlN material and substrate metals. The AlN film deposited on the Pt/Ti electrode reveals highly the c-axis orientation with well-textured columnar structure. The positive role of the Pt/Ti electrode in achieving the high-quality AlN films and high-performance film bulk acoustic resonator （FBAR） may be attributed to the smaller lattice mismatch as well as the similarity of thermal expansion coefficient between the deposited AlN material and the Pt/Ti electrode substrate.

关键词： AlN films substrate orientation crystallinity

Zero-voltage switching converter absorbing parasitic parameters for super high frequency induction heating

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Journal of zhejiang University-Science A(Applied Physics & Engineering) 2008年第4期9卷 564-571页

作者： zheng-shi WANG Hui-ming CHEN School of Electrical Engineering Zhejiang University Hangzhou 310027 China

This paper presents a novel mega-Hz-level super high frequency zero-voltage soft-switching converter for induction heating power supplies. The prominent advantage of this topology is that it can absorb both inductive and capacitive parasitic components in the converter. The switch devices operate in a zero-voltage soft-switching mode. Consequently, the high voltage and high current spikes caused by parasitic inductors or capacitors oscillation do not occur in this circuit, and the high power loss caused by high frequency switching can be greatly reduced. A large value inductor is adopted between the input capacitor and the switches, thus, this novel converter shares the benefits of both voltage-type and current-type circuits simultaneously, and there are no needs of dead time between two switches. The working principles in different modes are introduced. Results of simulation and experiments operated at around 1 MHz frequency verify the validity of parasitic components absorption and show that this convener is competent for super high frequency applications.

关键词： Induction heating Super high frequency Soft-switching converter Parasitic parameters

Model-guided 3D stitching for augmented virtual environment

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Science China(Information Sciences) 2023年第1期66卷 115-130页

作者： Zhong ZHOU ming MENG Yi ZHOU zhe ZHU Jingdi YOU State Key Laboratory of Virtual Reality Technology and Systems Beihang University Department of Radiology Duke University Beijing Big View Technology Co. Ltd.

Image and video stitching have made tremendous progress in the construction of wide field-of-view(FOV). However, some long-term challenges still exist, including wide baselines between cameras,large parallaxes, and low texture in overlapping areas. The augmented virtual environment(AVE) captures videos as live textures of 3D models in a virtual environment, and provides another 3D solution to overcome the aforementioned challenges. Existing AVE methods primarily follow from video projection, and cannot produce satisfactory stitching results compared with image stitching. In this paper, we propose a novel model-guided 3D stitching algorithm for AVE. The algorithm recovers an approximate 3D model for each video streaming and optimizes the warping of the models to meet the requirements of feature point matching of the 3D models from adjacent videos. Compared with previous state-of-the-art methods, experiment results illustrate that our method significantly improves the stitching quality.

关键词： 3D stitching video model multiple video visualization augmented virtual environment

Overview of deep space laser communication

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Science China(Information Sciences) 2018年第4期61卷 7-18页

作者： Weiren WU ming CHEN zhe ZHANG Xiangnan LIU Yuhui DONG School of Aerospace Engineering Beijing Institute of Technology Beijing Research Institute of Telemetry

The deep space probe is a vital technology for observing and exploring the universe. It is thus intensifying as an aerospace research focus on an international scale. Despite improving the frequency band,the conventional microwave communication technique has difficulty satisfying the increased demand for the enormous volume of scientific data returning to the Earth. With a carrier frequency that is several orders of magnitude higher than the microwave, free-space optical communication is a robust and promising method for achieving both high bit rates and long distances in deep space communication. In this article, the history of this technology is summarized and the objective laws are formulated, while key techniques and development trends are analyzed. Finally, useful concepts and suggestions are proposed for the development of deep space laser communication in China.

关键词： deep space communication deep space observation development process free space communication laser communication

In situ strengths of matrix in a composite

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Acta Mechanica Sinica 2017年第1期33卷 120-131页

作者： zheng-ming Huang Li-Min Xin Key Laboratory of the Ministry of Education for Advanced Civil Engineering Materials School of Aerospace Engineering and Applied Mechanics Tongji UniversityShanghai 200092 China

A major obstacle to achieving reasonable strength prediction of a composite only from its constituent information is in the determination of in situ strengths of the matrix. One can measure only the original strengths of the pure matrix, on the basis of which the predicted transverse strengths of a unidirectional (UD) composite are far from reality. It is impossible to reliably measure matrix in situ strengths. This paper focuses on the correlation between in situ and original strengths. Stress concentrations in a matrix owing to the introduction of fibers are attributed to the strength variation. Once stress concentration factors (SCFs) are obtained, the matrix in situ strengths are assigned as the original counterparts divided by them. Such an SCF cannot be defined following a classical approach. All of the relevant issues associated with determining it are systematically addressed in this paper. Analytical expressions for SCFs under transverse tension, transverse compression, and transverse shear are derived. Closed-form and compact formulas for all of the uniaxial strengths of a UD composite are first presented in this paper. Their application to strength predictions of a number of typical UD composites demonstrates the correctness of these formulas.

关键词： Composites Strength formulas Micromechanics Stress concentration factor Matrix in situ strength