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ENERGY-LOSS FUNCTIONS DERIVED FROm REELS SPECTRA FOR ALUmINUm

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Acta metallurgica Sinica(English Letters) 2005年第3期18卷 217-222页

作者： Z.m.Zhang Z.J.Ding h.m.li K.Salma X.Sun R.Shimizu T.Koshikawa K.Goto StructureResearchLaboratoryandDepartmentofPhysics UniversityofScienceandTechnologyofChinaTheChineseAcademyofSciencesHefei230026China DepartmentofInformationScience OsakaInstituteofTechnologyOsaka573-0196Japan FundamentalElectronicsResearchInstitute OsakaElectro-CommunicationUniversityOsaka572-8530Japan DepartmentofSystemsEngineering NagoyaInstituteofTechnologyNagoya466-8555Japan

The effective energy loss functions for Al have been derived from differential i nverse inelastic mean free path based on the extended Landau approach. It has be en revealed that the effective energy loss function is very close in value to th e theoretical surface energy loss function in the lower energy loss region but g radually approaches the theoretical bulk energy loss function in the higher ener gy loss region. moreover, the intensity corresponding to surface excitation in e ffective energy loss functions decreases with the increase of primary electron e nergy. These facts show that the present effective energy loss function describe s not only surface excitation but also bulk excitation. At last, REELS spectra s imulated by monte Carlo method based on use of the effective energy loss functio ns has reproduced the experimental REELS spectra with considerable success.

关键词： effective energy loss function monte Carlo simulation extended Landau approach reflection electron energy loss spectro scopy Aluminum

Computation of Biobjective/Bidisciplinary Optimization

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Computation of Biobjective/Bidisciplinary Optimization

On the Generation of Strong Core Field Inside Flux Rope:2-D mhD and hall mhD Simulation

第十一届全国计算流体力学会议

作者： Z.Q.Zhu h.Y.Fu R.X.Yu h.m.li Beijing University of Aeronautics and Astronautics. Beijing 100083China

1 Introduction It is well known that a modern fighter should have high aerodynamic performance, i.e., highlift (C) and low drag (C), high C/C at subsonic speed and low drag at supersonic speed, ***, stealthy performance has also become one of the basic requirements to a modern fighter. Sothe task of a designer today is to shape the aircraft with not only the maximum aerodynamic efficiencybut also a low observability. Up to now, reducing radar cross section (RCS) is the most importantpart of low observable technique for a flight vehicle. These requirements derive the development ofmultiobjective (mO)/multidisciplinary (mD) optimization. The goal of mO/mD optimization is toobtain one of the needed pareto solution at a minimum computing expense. A computational study ofbiobjective (BO)/bidisciplinary(BD) optimization of airfoils and wings is given in the present paper.

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On the Generation of Strong Core Field Inside Flux Rope:2-D ...

Fast efficient photon deceleration in plasmas by using two laser pulses at different frequencies

中国空间科学学会空间物理学专业委员会第十五届全国日地空间物理学研讨会

作者： Y.Pang m.Zhou S.Y.huang X.h.Deng Z.G.Yuan X.J.Xu h.m.li D.D.Wang Institute of Space Science and Technology Nanchang University Institute of Astronomy Nanchang University School of Electronic and Information Wuhan University

2-D mhD and hall mhD simulations are carried out to study the generation of the enhancement of core field inside flux ***,we systemically investigate the growth of core fieldoyB,at the center of the flux rope(the O point),with or without hall *** contrary to previous simulation results[liu et al.,2009],we find that a nonlinear growth ofoyB,is simply due to the interaction between two reconnection jets ejected from two adjacent X lines,rather than the interaction between the hall effect and pre-existed guide *** develop a simple theoretical model to semi-quantitatively describe how such an interaction(between reconnection jets)causes the explosive growth ofoyB,.In addition,we also find that hall magnetic field can directly contributes to the enhancement ofoyB,via"re-reconnection"process in small scale flux rope and will lead to the saturated value ofoyB,slightly higher than those of large ones.

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matter and Radiation at Extremes 2024年第3期9卷 11-18页

作者： Y.X.Wang X.L.Zhu S.m.Weng P.li X.F.li h.Ai h.R.Pan Z.m.Sheng Key Laboratory for Laser Plasmas(moe) School of Physics and AstronomyShanghai Jiao Tong UniversityShanghai 200240China Collaborative Innovation Center of IFSA Shanghai Jiao Tong UniversityShanghai 200240China Research Center of Laser Fusion of China Academy of Engineering Physics MianyangSichuan 621900China State key Laboratory of high Field Laser Physics Shanghai Institute of Optics and Fine MechanicsChinese Academy of SciencesShanghai 201800China Tsung-dao Lee Institute Shanghai Jiao Tong UniversityShanghai 200240China

The generation of ultrashort high-power light sources in the mid-infrared(mid-IR)to terahertz(Thz)range is of interest for applications in a number of fields,from fundamental research to biology and *** conventional laser technology,photon deceleration in plasma wakes provides an alternative approach to the generation of ultrashort mid-IR or Thz ***,we present a photon deceleration scheme for the efficient generation of ultrashort mid-IR or Thz pulses by using an intense driver laser pulse with a relatively short wavelength and a signal laser pulse with a relatively long *** signal pulse trails the driver pulse with an appropriate time delay such that it sits at the front of the second wake bubble that is driven by the driver *** to its relatively long wavelength,the signal pulse will be subjected to a large gradient of the refractive index in the plasma wake ***,the photon deceleration in the plasma wake becomes faster and more efficient for signal pulses with longer *** greatly enhances the capacity and efficiency of photon deceleration in the generation of ultrashort high-power light sources in the long-wavelength IR and Thz spectral ranges.

关键词： laser ultrashort photon

Greatly enhanced corrosion/wear resistances of epoxy coating for mg alloy through a synergistic effect between functionalized graphene and insulated blocking layer

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Journal of magnesium and Alloys 2024年第1期12卷 332-344页

作者： Z.Y.Xue X.J.li J.h.Chu m.m.li D.N.Zou L.B.Tong School of metallurgical Engineering Xi’an University of Architecture and TechnologyXi’an 710055China State Key Laboratory of Advanced Design and manufacturing for Vehicle Body Hunan UniversityChangsha 410082China

The poor corrosion and wear resistances of mg alloys seriously limit their potential applications in various *** conventional epoxy coating easily forms many intrinsic defects during the solidification process,which cannot provide sufficient *** the current study,we design a double-layer epoxy composite coating on mg alloy with enhanced anti-corrosion/wear properties,via the spin-assisted assembly *** outer layer is functionalized graphene(FG)in waterborne epoxy resin(WEP)and the inner layer is Ce-based conversion(Ce)*** FG sheets can be homogeneously dispersed within the epoxy matrix to fill the intrinsic defects and improve the barrier *** Ce film connects the outer layer with the substrate,showing the transition *** corrosion rate of Ce/WEP/FG composite coating is 2131 times lower than that of bare mg alloy,and the wear rate is decreased by~90%.The improved corrosion resistance is attributed to the labyrinth effect(hindering the penetration of corrosive medium)and the obstruction of galvanic coupling *** synergistic effect derived from the FG sheet and blocking layer exhibits great potential in realizing the improvement of multi-functional integration,which will open up a new avenue for the development of novel composite protection coatings of mg alloys.

关键词： mg alloy Functionalized graphene Epoxy coating Corrosion/wear resistance Blocking layer

Free vibration and buckling analysis of polymeric composite beams reinforced by functionally graded bamboo fbers

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Applied mathematics and mechanics(English Edition) 2024年第3期45卷 543-562页

作者： h.m.FEIZABAD m.h.YAS Department of mechanical Engineering Razi UniversityKermanshah ***Iran

Natural fibers have been extensively researched as reinforcement materials in polymers on account of their environmental and economic advantages in comparison with synthetic fibers in the recent *** fibers are renowned for their good mechanical properties,abundance,and short cycle *** beams are one of the fundamental structural components and are susceptible to mechanical loads in engineering applications,this paper performs a study on the free vibration and buckling responses of bamboo fiber reinforced composite(BFRC)beams on the elastic *** different functionally graded(FG)layouts and a uniform one are the considered distributions for unidirectional long bamboo fibers across the *** elastic properties of the composite are determined with the law of *** hamilton’s principle,the governing equations of motion are *** generalized differential quadrature method(GDQm)is then applied to the equations to obtain the *** achieved outcomes exhibit that the natural frequency and buckling load values vary as the fiber volume fractions and distributions,elastic foundation stiffness values,and boundary conditions(BCs)and slenderness ratio of the beam ***,a comparative study is conducted between the derived analysis outcomes for BFRC and homogenous polymer beams to examine the effectiveness of bamboo fibers as reinforcement materials,demonstrating the significant enhancements in both vibration and buckling responses,with the exception of natural frequencies for cantilever beams on the Pasternak foundation with the FG-◇fiber ***,the obtained analysis results of BFRC beams are also compared with those for carbon nanotube reinforced composite(CNTRC)beams found in the literature,indicating that the buckling loads and natural frequencies of BFRC beams are lower than those of CNTRC beams.

关键词： bamboo fiber free vibration buckling analysis functionally graded(FG)beam elastic foundation generalized differential quadrature method(GDQm)

Convexification of hybrid AC-DC Optimal Power Flow with line-Commutated Converters

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 617-628页

作者： hongyuan liang Zhigang li J.h.Zheng Q.h.Wu School of Electric Power Engineering South China University of TechnologyGuangzhou 510641China

line-commutated converter (LCC)-based high-voltage DC (hVDC) systems have been integrated with bulk AC power grids for interregional transmission of renewable power. The nonlinear LCC model brings additional nonconvexity to optimal power flow (OPF) of hybrid AC-DC power grids. A convexification method for the LCC station model could address such nonconvexity but has rarely been discussed. We devise an equivalent reformulation for classical LCC station models that facilitates second-order cone convex relaxation for the OPF of LCC-based AC-DC power grids. We also propose sufficient conditions for exactness of convex relaxation with its proof. Equivalence of the proposed LCC station models and properties, exactness, and effectiveness of convex relaxation are verified using four numerical simulations. Simulation results demonstrate a globally optimal solution of the original OPF can be efficiently obtained from relaxed model.

关键词： AC-DC power system convex relaxation linecommutated converter optimal power flow second-order cone programming

Editorial for the Special Issue on Emerging Technology and Advanced Application of Nondestructive Detection for Power Equipment

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Chinese Journal of Electrical Engineering 2024年第1期10卷 1-2页

作者： li J. mei h. li S. Tianjin University China Tsinghua Shenzhen International Graduate School China Lanzhou Jiaotong University China

The rapid development of clean and renewable energy technologies represented by wind and solar energy,as well as the continuous growth of load demand,have put forward higher requirements for the safe operation of the power *** performance of power equipment based on traditional dielectric materials is often limited by various defects generated during molding,transportation,assembly,and operation,which cannot meet the reliability requirements of power systems in the new *** detection is an essential technical method in industrial development,which can detect and evaluate the defect and damage status of in-service equipment,key components,and materials without damaging the object.

关键词： service Application operation

A hybrid Signal Processing method Combining mathematical morphology and Walsh Theory for Power Quality Disturbance Detection and Classification

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 584-592页

作者： Zhi Ding Tianyao Ji mengshi li Q.h.Wu School of Electric Power Engineering South China University of Technology(SCUT)Guangzhou 510641China

In this paper, a novel signal processing method combining mathematical morphology (mm) and Walsh theory is proposed, which uses Walsh functions to control the structuring element (SE) and mm operators. Based on the Walsh-mm method, a scheme for power quality disturbances detection and classification is developed, which involves three steps: denoising, feature extraction and morphological clustering. First, various evolution rules of Walsh function are used to generate groups of SEs for the multiscale Walsh-ordered morphological operation, so the original signal can be denoised. Next, the fundamental wave of the denoised signal is suppressed by hadamard matrix;thus, disturbances can be extracted. Finally, the Walsh power spectrum of the waveform extracted in the previous step is calculated, and the parameters of which are taken by morphological clustering to classify the disturbances. Simulation results reveal the proposed scheme can effectively detect and classify disturbances, and the Walsh-mm method is less affected by noise and only involves simple calculation, which has a potential to be implemented in hardware and more suitable for real-time application.

关键词： hadamard matrix mathematical morphology morphological clustering power quality disturbance Walsh theory