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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

Effect of Placements (horizontal with vertical) on Gas-solid Flow and Particle Impact Erosion in Gate Valve

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Journal of Thermal Science 2014年第6期23卷 558-563页

作者： LIN zhe zhu Linhang CUI Baoling LI Yi RUAN Xiaodong The zhejiang Provincial Key Laboratory of Fluid Transmission Technology Zhejiang Sci-Tech University 1201 Chu Kochen Honor College Zhejiang University State Key Laboratory of Fluid Power Transmission and Control Zhejiang University

Gate valve has various placements in the practical *** to the effect of gravity,particle trajectories and erosions are distinct between *** in this study,gas-solid flow properties and erosion in gate valve for horizontal placement and vertical placement are discussed and compared by using Euler-Lagrange simulation *** structure of a gate valve and a simplified structure are *** simulation procedure is validated in our published paper by comparing with the experiment data of a pipe and an *** results show that for all investigated open degrees and Stokes numbers(St),there are little difference of gas flow properties and flow coefficients between two *** is also found that the trajectories of particles for two placements are mostly identical when St << 1,making the erosion independent of *** the increase of St,the distinction of trajectories between placements becomes more obvious,leading to an increasing difference of the erosion ***,the total erosion ratio of surface T for horizontal placement is two orders of magnitudes larger than that for vertical placement when the particle diameter is 250 μm.

关键词： gate valve placement flow properties erosion

Quantum discord in the three-spin XXZ chain with Dzyaloshinskii-Moriya interaction

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Science China(Physics,Mechanics & Astronomy) 2012年第11期55卷 2081-2087页

作者： zhu YinYan ZHANG yong School of Science Beijing University of Posts and TelecommunicationsBeijing 100876China

The quantum discord(QD) of a three-qubit Heisenberg XXZ system with the Dzyaloshinskii-Moriya(DM) interaction parameter is investigated,and the three-qubit QD under Ornstein-Uhlenbeck noise is *** find that both DM interaction parameter D z and anisotropic parameter J z can increase QD and entanglement but D z is a more efficient parameter in the antiferromagnetic *** observe a complex range of QD with the change of D z and a sudden change of QD with the variation of J z in the ferromagnetic *** show that the decrease durations of both QD and entanglement can be prolonged by increasing DM interaction and reducing noise bandwidth in the evolutionary process.

关键词： quantum discord XXZ-spin chain DM interaction Ornstein-Uhlenbeck noise

NONLINEAR WATER WAVES IN LAGRANGIAN COORDINATES:SHALLOW FLUIDS

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Journal of Hydrodynamics 1996年第4期8卷 25-34页

作者： Tian, Mei zhu, yong Shanghai Univ Shanghai China

In this paper the KdV equation has been derived by using the Lagrangian coordinates and the head-on collision between solitary waves was studied without the assumption of irrotational motion condition. It is found tha... 详细信息

关键词： Computer simulation Flow of water Hydrodynamics Nonlinear equations Numerical analysis Water wave effects

A three-stage real-time detector for traffic signs in large panoramas

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Computational Visual Media 2019年第4期5卷 403-416页

作者： Yizhi Song Ruochen Fan Sharon Huang zhe zhu Ruofeng Tong Department of Computer Science Purdue University305 N.University StreetWest LafayetteIN 47907USA Department of Computer Science and Technology Tsinghua UniversityBeijing 100084China College of Information Sciences and Technology Penn State UniversityUniversity ParkPA 16802USA Department of Radiology Duke UniversityDurhamNC 27705USA College of Computer Science and Technology Zhejiang UniversityHangzhou 310007China

Traffic sign detection is one of the key components in autonomous *** autonomous vehicles armed with high quality sensors capture high definition images for further *** traffic signs,moving vehicles,and lanes is important for localization and decision *** signs,especially those that are far from the camera,are small,and so are challenging to traditional object detection *** this work,in order to reduce computational cost and improve detection performance,we split the large input images into small blocks and then recognize traffic signs in the blocks using another detection ***,this paper proposes a three-stage traffic sign detector,which connects a Block Net with an RPN–RCNN detection *** Net,which is composed of a set of CNN layers,is capable of performing block-level foreground detection,making inferences in less than 1 ***,the RPN–RCNN two-stage detector is used to identify traffic sign objects in each block;it is trained on a derived dataset named TT100 *** show that our framework can achieve both state-of-the-art accuracy and recall;its fastest detection speed is 102 fps.

关键词： traffic sign detection real time

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

Effects of process parameters on fragment and refinement of millimeter- grade coarse grains for 316LN steel during hot cogging

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Journal of Iron and Steel Research International 2017年第5期24卷 529-535页

作者： Da-shan Sui Hai-ming Zhang Hong-yang zhu zhe zhu zhen-shan Cui National Die & Mold CAD Engineering Research Center Shanghai Jiao Tong University Shanghai 200030 China Shanghai Heavy Machinery Plant Shanghai 200245 China

The heterogeneous mixed-grain microstructure is a common defect for the heavy forging of 316LN austenitie stainless steel. Isothermal compression experiments were performed on a Gleeble-3500 thermo-mechanical simulator to investigate the effect of process parameters on the fragment and re- finement of millimeter-grade coarse grains （MCGs） during hot cogging. The experimental results in- dicate that the stress of MCG specimens is much larger than that of fine grain （FG） ones at 1150 ℃, while the stress difference between MCG and FG samples became smaller at 1200 ℃. Moreover, the MCGs can be well fragmented and refined under the condition of temperature of 1200 ℃, strain rate of 0.01 s-1 , and reduction rate of 50%. Meanwhile, numerical simulations were conducted to study the influences of temperature, strain and strain rate on microstructure evolution. The results of ex- periments and simulations comprehensively demonstrate that the MCG results in the increase of de- formation resistance and incompatibility of deformation, and it can be fragmented and refined at 1200 ℃ so that the plastic deformation energy decreases remarkably with the increase of temperature from 1 150 to 1200 ℃.

关键词： 316LN steel Hot deformation Coarse grain Microstrueture evolution Numerical simulation

High-order Soliton Matrix for the Third-order Flow Equation of the Gerdjikov-Ivanov Hierarchy Through the Riemann-Hilbert Method

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Acta Mathematicae Applicatae Sinica 2024年第2期40卷 358-378页

作者： Jin-yan zhu yong CHEN School of Mathematical Sciences Shanghai Key Laboratory of Pure Mathematics and Mathematical PracticeEast China Normal UniversityShanghai 200062China College of Mathematics and Systems Science Shandong University of Science and TechnologyQingdao 266590China

The Gerdjikov-Ivanov(GI)hierarchy is derived via recursion operator,in this article,we mainly investigate the third-order flow GI *** the framework of the Riemann-Hilbert method,the soliton matrices of the third-order flow GI equation with simple zeros and elementary high-order zeros of Riemann-Hilbert problem are constructed through the standard dressing *** advantage of this result,some properties and asymptotic analysis of single soliton solution and two soliton solution are discussed,and the simple elastic interaction of two soliton are *** with soliton solution of the classical second-order flow,we find that the higher-order dispersion term affects the propagation velocity,propagation direction and amplitude of the ***,by means of a certain limit technique,the high-order soliton solution matrix for the third-order flow GI equation is derived.

关键词： Gerdjikov-Ivanov hierarchy third-order flow GI equation Riemann-Hilbert method high-order soliton

Direct Laser Writing Facility for Fabrication of Submicron Mask

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Chinese Physics Letters 2014年第4期31卷 185-188页

作者： zhu Feng MA Jian-yong Information Optics Laboratory Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences Shanghai 201800

Direct laser writing technique has become a well-established, multi-functional and flexible method for fabricating high quality diffractive optical elements. We propose and build a maskless direct laser writing system with the ability to produce a sub-micron feature size. The high precision lithography is realized by using the astigmatic autofocus method. The minimum feature size of the system, breaking through the diffraction limit with the chromium layer, can achieve 300hm with the 405nm blue laser. A 50 x 50ram2 chromium grating mask with a period of 1 #m and line width of 300 nm is fabricated. This facility will be useful for the fabrication of large-scale submicron diffraction optical elements in the future.

关键词： FABRICATION (Manufacturing) DIFFRACTIVE optical elements CHROMIUM -- Spectra BLUE lasers OPTICAL diffraction ASTIGMATISM (Optics)

The Asymptotic Distributions of the Largest Entries of Sample Correlation Matrices under an α-mixing Assumption

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Acta Mathematica Sinica,English Series 2022年第11期38卷 2039-2056页

作者： Hao zhu ZHAO yong ZHANG School of Mathematics Jilin UniversityChangchun 130012P.R.China

Let{Xk,i;k≥1,i≥1}be an array of random variables,{Xk;k≥1}be a strictly stationaryα-mixing sequence,where Xk=(Xk,1,Xk,2,...).Let{pn;n≥1}be a sequence of positive integers such that c1≤p n n≤c2,where c1,c2>*** th... 详细信息

关键词： Sample correlation matrices α-mixing sequence Chen-Stein method