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Connected Vehicle-Based Traffic Signal Coordination

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Engineering 2020年第12期6卷 1463-1472页

作者： wan li Xuegang Ban Oak Ridge National Laboratory KnoxvilleTN 37932USA University of Washington SeattleWA 98195USA

This study presents a connected vehicles(CVs)-based traffic signal optimization framework for a coordinated arterial *** signal optimization and coordination problem are first formulated in a centralized scheme as a mixed-integer nonlinear program(MINLP).The optimal phase durations and offsets are solved together by minimizing fuel consumption and travel time considering an individual vehicle’s *** to the complexity of the model,we decompose the problem into two levels:an intersection level to optimize phase durations using dynamic programming(DP),and a corridor level to optimize the offsets of all *** order to solve the two-level model,a prediction-based solution technique is *** proposed models are tested using traffic simulation under various *** with the traditional actuated signal timing and coordination plan,the signal timing plans generated by solving the MINLP and the two-level model can reasonably improve the signal control *** considering varies vehicle types under high demand levels,the proposed two-level model reduced the total system cost by 3.8%comparing to baseline actuated *** reduced the system cost by 5.9%.It also suggested that coordination scheme was beneficial to corridors with relatively high demand *** intersections with major and minor street,coordination conducted for major street had little impacts on the vehicles at the minor street.

关键词： Connected vehicles Traffic signal coordination Dynamic programming Two-level optimization Mixed-integer nonlinear program

Highly parallel implementation of sub-pixel interpolation for AVS HDTV decoder

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第12期9卷 1638-1643页

作者： wan-yi li Lu YU Institute of Information and Communication Engineering Zhejiang University Hangzhou 310027 China

In this paper, we propose an effective VLS1 architecture of sub-pixel interpolation for motion compensation in the AVS HDTV decoder. To utilize the similar arithmetical operations of 15 luma sub-pixel positions, three types of interpolation filters are proposed. A simplified multiplier is presented due to the limited range of input in the chroma interpolation process. To improve the processing throughput, a parallel and pipelined computing architecture is adopted. The simulation results show that the proposed hardware implementation can satisfy the real-time constraint for the AVS HDTV （1 920× 1 088） 30 fps decoder by operating at 108 MHz with 38.18k logic gates. Meanwhile, it costs only 216 cycles to accomplish one macroblock, which means the B frame sub-pixel interpolation can be realized by using only one set of the proposed architecture under real-time constraints.

关键词： VLSI architecture Interpolation AVS HDTV

Photocatalysts of Cr Doped TiO2 Film Prepared by Micro Arc Oxidation

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Chinese Journal of Chemical Physics 2008年第5期21卷 487-492页

作者： li wan Jian-feng li Jia-you Feng Wei Sun Department of Material Science and Engineering of Education Tsinghua University Beijing 100084China Institute of Nuclear and New Energy Technology Tsinghua University Beijing 100084 China

A series of Cr doped TiO2 films were prepared by micro arc oxidation （MAO） using an electrolyte of Na3PO4＋K2Cr2O7. X-ray diffraction and scanning electron microscopy revealed that the films mainly consisted of anatase phase with a porous surface morphology. The films have an excellent photocatalytic effect for degradation of methylene blue and decomposition of water under visible light illumination. This arises from the formation of Cr3＋/Cr4＋ and oxygen vacancy energy levels owing to Cr doping. The former reduces the electron-hole recombination chance, while the latter generates a new gap between the conduction band （CB） and valence band （VB） of TiO2, which lowers the photo energy of the excited electron in the VB to the oxygen vacancy states. The mechanisms for film synthesis during the MAO process are also presented.

关键词： TiO2 Cr doping Photocatalysis Micro arc oxidation

NUMERICAL STUDY OF 3D EXPLOSION BUBBLES ADJACENT TO STRUCTURES

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Journal of Hydrodynamics 2002年第4期14卷 66-72页

作者： li, wan-Ping li, liang-Jun Dept. of Mech. Huazhong Univ. of Sci. and Technol. Wuhan 430074 China

The bejavior of a bubble near a rigid structure was considered by using the local surface fitting method and the jet prediction method. The convergence difficulty caused by the abnormality of the elements was overcome. The flow was numerically simulated by using the boundary-integral method on the assumption that the water was inviscid and incompressible, and the bubble gas obeyed the isentropic rule. The evolution of the bubble was investigated by means of the mixed Euler-Lagrange method, and the Runge-Kutta method. The important behavior of the bubble, such as migration and jetting, was analyzed in several examples. The solution of one period of the explosion bubble was obtained.

关键词： Bubbles (in fluids) Shock waves Structures (built objects)

Thermal-Hydraulic Calculation and Analysis on Evaporator System of a 1000 MW Ultra-Supercritical Pulverized Combustion Boiler with Double Reheat

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Journal of Thermal Science 2021年第3期30卷 807-816页

作者： wan li YANG Dong ZHOU Xihong DONG Le li Juan State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an 710049China

A double reheat ultra-supercritical boiler is an important development direction for high-parameter and large-capacity coal-fired power plants due to its high thermal efficiency and environmental *** has developed a 1000 MW double reheat ultra-supercritical boiler with steam parameters of 35 MPa at 605℃/613℃/613℃.Reasonable water wall design is one of the keys to safe and reliable operation of the *** order to examine the thermal-hydraulic characteristics of the double reheat ultra-supercritical boiler,the water wall system was equivalent to a flow network comprising series-parallel circuits,linking circuits and pressure nodes,and a calculation model was built on account of the conservation equations of energy,momentum and *** the iterative solving of nonlinear equations,the prediction parameters of the water wall at boiler maximum continue rate(BMCR),75%turbine heat-acceptance rate(THA)and 30%THA loads,including total pressure drops,flow distribution,outlet steam temperatures,fluid and metal temperatures were *** results of calculation exhibit excellent thermal-hydraulic characteristics and substantiate the feasibility of the water wall design of the double reheat ultra-supercritical boiler.

关键词： double reheat ultra-supercritical boiler water wall flow network method thermal-hydraulic characteristic

Solitary Wave Solutions of Delayed Coupled Higgs Field Equation

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Acta Mathematica Sinica,English Series 2022年第1期38卷 97-106页

作者： Shu Guan JI Xiao wan li School of Mathematics and Statistics and Center for Mathematics and Interdisciplinary SciencesNortheast Normal UniversityChangchun 130024P.R.China School of Mathematics Jilin UniversityChangchun 130012P.R.China College of Mathematics and System Science Xinjiang UniversityUrumqi 830046P.R.China

This paper is devoted to the study of the solitary wave solutions for the delayed coupled Higgs field equation{vtt-uxx-αu+βf*u|u|^(2)-2uv-τu(|u|^(2))x=0 vtt+vxx-β(|u|^(x))xx=*** first establish the existence of solitary wave solutions for the corresponding equation without delay and perturbation by using the Hamiltonian system *** we consider the persistence of solitary wave solutions of the delayed coupled Higgs field equation by using the method of dynamical system,especially the geometric singular perturbation theory,invariant manifold theory and Fredholm *** to the relationship between solitary wave and homoclinic orbit,the coupled Higgs field equation is transformed into the ordinary differential equations with fast variables by using the variable *** is proved that the equations with perturbation also possess homoclinic orbit,and thus we obtain the existence of solitary wave solutions of the delayed coupled Higgs field equation.

关键词： delayed coupled Higgs field equation solitary wave solutions geometric singular perturbation theory Fredholm theory homoclinic orbit

Enhanced strength and electrical conductivity of Al-0.3Ce alloy simultaneously with Ti(C,N)nanoparticle addition

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Rare Metals 2021年第7期40卷 1890-1896页

作者： wan-Peng li Yu-liang Zhang Jian Mao College of Materials Science and Engineering Sichuan UniversityChengdu 610065China

Ti(C,N)nanoparticles were added to an Al-0.3 Ce alloy by ultrasonic *** annealing at 570℃for4 h afforded the ultimate tensile strength of 79 MPa and electrical conductivity of 64.0%IACS for the Al-0.3 Ce alloy with1.5 vol%Ti(C,N)*** performance parameters were improved by 23.4%and 0.6%IACS,respectively,compared with those of casting refining pure aluminum(64 MPa and63.4%IACS).This could be explained by the following *** addition of Ti(C,N)nanoparticles could significantly refine the grain of Al-0.3 Ce ***,most of the coarse strip-shaped second phases distributed at the grain boundaries in Al-0.3 Ce were also transformed into spherical microparticles distributed in the grains,with micro-nano hierarchical structures comprising orientated nanosized strip phases with lengths of~400 nm and widths of~100 ***,a fine micro-nano hierarchical spherical structure could be obtained after annealing at 570℃for 4 *** numbers of micro-nano hierarchical spherical structures also increased due to the precipitation of pseudosolution Ce from the aluminum matrix during the annealing treatment.

关键词： Conductive aluminum alloy Ti(C,N)nanoparticles Ce Micro-nano hierarchical spherical structure Annealing treatment

Preparation and characterization of γ-La_2S_3 nanoparticles from thermal decomposition

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International Journal of Minerals,Metallurgy and Materials 2011年第6期18卷 748-752页

作者： Pei-sen li Huan-yong li wan-qi Jie School of Materials Science and Engineering Northwestern Polytechnical University Xi＇an 710072 China

To synthesize pure γ-La2S3 at lower temperature,lanthanide complex La（Et2S2CN）3·phen,containing La？S bond,was chosen as the precursors to *** obtained samples were characterized by X-ray power diffraction （XRD）,field-emission scanning electron microscopy （FE-SEM） with an energy dispersive spectrometer and UV-Vis diffuse reflectance *** decomposition mechanism of the lanthanide complex was studied by thermogravimetric analyses （TGA）.The results show that the obtained samples are cubic phase particles with sizes among 20-50 nm and the band gap is 2.97 eV,which is bigger than that of its bulk ***/DTG results indicate that La（Et2S2CN）3·phen decomposed to γ-La2S3 via La4（Et2S2CN）3 as an intermediate product.

关键词： chalcogenides nanoparticles thermogravimetric analysis decomposition optical properties

Positive Solutions for Second-Order m-Point Boundary Value Problems on Time Scales

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Acta Mathematica Sinica,English Series 2006年第6期22卷 1797-1804页

作者： wan Tong li Hong Rui SUN School of Mathematics and Statistics Lanzhou University Lanzhou 730000 P. R. China

Let T be a time scale such that 0, T ∈ T. By means of the Schauder fixed point theorem and analysis method, we establish some existence criteria for positive solutions of the m-point boundary value problem on time scales where α ∈ Ctd（（O,T,[0,∞））,f∈ Ckd（[0,∞）×[0,∞））,β,γ ∈[0,∞）,ξi ∈（0,p（T）.b,ai∈ （0,∞）（for i = 1,..., m - 2） are given constants satisfying some suitable hypotheses. We show that this problem has at least one positive solution for sufficiently small b 〉 0 and no solution for sufficiently large b. Our results are new even for the corresponding differential equation （T = R） and difference equation （T = Z）.

关键词： time scales positive solution Schauder fixed point theorem