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High Power Laser Science and Engineering 2024年第1期12卷 116-116页

作者： J.Goodman m.king E.J.Dolier R.Wilson R.J.Gray P.mcKenna 不详

Due to an isolated error in the 3D simulation parameters,the laser energy and intensity(calculated using the energy)values were incorrectly stated as 10.9 J and 3×10^(22) W cm^(−2),respectively,in Sections 3.3,7 and *** correct values are 39.8 J and 1.1×10^(23) W cm^(−2).Similarly,the values stated for the higher energy case,109 J and 3×10^(23) W cm^(−2) in Section 7,should be 398 J and 1.1×10^(24) W cm^(−2),respectively.

关键词： Bayesian optimization gamma rays laser-solid interactions machine learning radiation reaction

Optimization and control of synchrotron emission in ultraintense laser–solid interactions using machine learning

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高功率激光科学与工程:英文版 2023年第3期11卷 15-31页

作者： J.Goodman m.king E.J.Dolier R.Wilson R.J.Gray P.mcKenna SUPA Department of Physics University of StrathclydeGlasgowUK The Cockcroft Institute Sci-Tech DaresburyWarringtonUK

The optimum parameters for the generation of synchrotron radiation in ultraintense laser pulse interactions with planar foils are investigated with the application of Bayesian optimization,via Gaussian process regression,to 2D particle-incell *** properties of the synchrotron emission,such as the yield,are maximized,and simultaneous mitigation of bremsstrahlung emission is achieved with multi-variate objective *** angle-of-incidence of the laser pulse onto the target is shown to strongly influence the synchrotron yield and angular profile,with oblique incidence producing the optimal *** is further explored in 3D simulations,in which additional control of the spatial profile of synchrotron emission is demonstrated by varying the polarization of the laser *** results demonstrate the utility of applying a machine learning-based optimization approach and provide new insights into the physics of radiation generation in laser-foil interactions,which will inform the design of experiments in the quantum electrodynamics(QED)-plasma regime.

关键词： Bayesian optimization gamma rays laser-solid interactions machine learning radiation reaction

High order modes of intense second harmonic light produced from a plasma aperture

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matter and Radiation at Extremes 2022年第5期7卷 7-16页

作者： E.F.J.Bacon m.king R.Wilson T.P.Frazer R.J.Gray P.mcKenna SUPA Department of Physics University of StrathclydeGlasgow G40NGUnited Kingdom The Cockcroft Institute Sci-Tech DaresburyWarrington WA44ADUnited Kingdom

Because of their ability to sustain extremely high-amplitude electromagnetic fields and transient density and field profiles,plasma optical components are being developed to amplify,compress,and condition high-power laser *** recently demonstrated the potential to use a relativistic plasma aperture—produced during the interaction of a high-power laser pulse with an ultrathin foil target—to tailor the spatiotemporal properties of the intense fundamental and second-harmonic light generated[Duff et al.,***.10,105(2020)].Herein,we explore numerically the interaction of an intense laser pulse with a preformed aperture target to generate second-harmonic laser light with higher-order spatial *** maximum generation efficiency is found for an aperture diameter close to the full width at half maximum of the laser focus and for a micrometer-scale target *** spatial mode generated is shown to depend strongly on the polarization of the drive laser pulse,which enables changing between a linearly polarized TEm01 mode and a circularly polarized Laguerre–Gaussian LG01 *** demonstrates the use of a plasma aperture to generate intense higher-frequency light with selectable spatial mode structure.

关键词： polarization intense harmonic

Stiffness-damping matching method of an ECAS system based on LQG control

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Journal of Central South University 2014年第1期21卷 439-446页

作者：陈一锴何杰 m.king 陈无畏张卫华 School of Transportation Engineering Hefei University of Technology Traffic management Research Institute of the ministry of Public Security School of Transportation Southeast University Centre for Accident Research and Road Safety-Queensland Queensland University of TechnologyKelvin Grove 4059Australia School of mechanical and Automotive Engineering Hefei University of Technology

A novel method of matching stiffness and continuous variable damping of an ECAS(electronically controlled air suspension) based on LQG(linear quadratic Gaussian) control was proposed to simultaneously improve the road-friendliness and ride comfort of a two-axle school *** account of the suspension nonlinearities and target-height-dependent variation in suspension characteristics,a stiffness model of the ECAS mounted on the drive axle of the bus was developed based on thermodynamics and the key parameters were obtained through field *** determining the proper range of the target height for the ECAS of the fully-loaded bus based on the design requirements of vehicle body bounce frequency,the control algorithm of the target suspension height(i.e.,stiffness) was derived according to driving speed and road *** account of the nonlinearities of a continuous variable semi-active damper,the damping force was obtained through the subtraction of the air spring force from the optimum integrated suspension force,which was calculated based on LQG ***,a GA(genetic algorithm)-based matching method between stepped variable damping and stiffness was employed as a benchmark to evaluate the effectiveness of the LQG-based matching *** results indicate that compared with the GA-based matching method,both dynamic tire force and vehicle body vertical acceleration responses are markedly reduced around the vehicle body bounce frequency employing the LQG-based matching method,with peak values of the dynamic tire force PSD(power spectral density) decreased by 73.6%,60.8% and 71.9% in the three cases,and corresponding reduction are 71.3%,59.4% and 68.2% for the vehicle body vertical acceleration.A strong robustness to variation of driving speed and road roughness is also observed for the LQG-based matching method.

关键词： LQG控制匹配方法刚度匹配可变阻尼 CAS系统电控空气悬架线性二次型高斯垂直加速度

Comparison of two suspension control strategies for multi-axle heavy truck

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Journal of Central South University 2013年第2期20卷 550-562页

作者：陈一锴何杰 m.king 冯忠祥张卫华 School of Transportation Engineering Hefei University of Technology Traffic management Research Institute of ministry of Public Security College of Transportation Southeast University Centre for Accident Research & Road Safety-Queensland Queensland University of Technology

Two simple and effective control strategies for a multi-axle heavy truck, modified skyhook damping (mSD) control and proportional-integration-derivative (PID) control, were implemented into functional virtual prototype (FVP) model and compared in terms of road friendliness and ride comfort. A four-axle heavy truck-road coupling system model was established using FVP technology and validated through a ride comfort test. Then appropriate passive air suspensions were chosen to replace the rear tandem suspensions of the original truck model for preliminary optimization. The mechanical properties and time lag of dampers were taken into account in simulations of mSD and PID semi-active dampers implemented using mATLAB/Simulink. Through co-simulations with Adams and mATLAB, the effects of semi-active mSD and PID control were analyzed and compared, and control parameters which afforded the best comprehensive performance for each control strategy were chosen. Simulation results indicate that compared with the passive air suspension truck, semi-active mSD control improves both ride comfort and road-friendliness markedly, with optimization ratios of RmS vertical acceleration and RmS tyre force ranging from 10.1% to 44.8%. However, semi-active PID control only reduces vertical vibration of the driver's seat by 11.1%, 11.1% and 10.9% on A, B and C level roads respectively. Both strategies are robust to the variation of road level.

关键词：控制策略重型卡车空气悬架多轴 mATLAB仿真 PID控制 Simulink 比例积分微分

Structural brain differences between ultra-endurance athletes and sedentary persons

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Sports medicine and Health Science 2020年第2期2卷 89-94页

作者： T.Paruk L.Rauch m.Jankiewicz K.Van Breda D.J.Stein m.king Department of Exercise Science and Sports medicine University of Cape TownSouth Africa Division of Biomedical Engineering Department of Human BiologyUniversity of Cape TownSouth Africa SAmRC Unit on Risk&Resilience in mental Disorders Dept of Psychiatry&Neuroscience InstituteUniversity of Cape TownSouth Africa

Participation in ultra-endurance events has increased in recent years and requires extreme levels of moderate to vigorous physical activity(mVPA).moderate levels of mVPA have been associated with increased brain volume but the effects of extreme levels of mVPA on brain volume is *** a result,we sought to compare the brains of those who engage in extremely high levels of mVPA with those who are sedentary using magnetic resonance *** performed whole brain volumetric analyses and voxel-based morphometry on 12 ultraendurance athletes(1078.75±407.86 min of mVPA/week)and 9 sedentary persons(18.0±56.9 min of mVPA/week).Whole-brain analyses revealed that those who participate in ultra-endurance training have increased grey(pmatter volume(pmaller regional grey matter volume in the right primary sensory and motor cortex,inferior and middle frontal gyrus,and left *** research is warranted to determine why ultra-endurance athletes have lower regional volumes in these areas despite having overall increased grey and white matter volumes.

关键词： Ironman athletes Ultra-racing Ultra-training mRI Ultra endurance

Automated control and optimization of laser-driven ion acceleration

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高功率激光科学与工程:英文版 2023年第3期11卷 32-40页

作者： B.Loughran m.J.V.Streeter H.Ahmed S.Astbury m.Balcazar m.Borghesi N.Bourgeois C.B.Curry S.J.D.Dann S.DiIorio N.P.Dover T.Dzelzainis O.C.Ettlinger m.Gauthier L.Giuffrida G.D.Glenn S.H.Glenzer J.S.Green R.J.Gray G.S.Hicks C.Hyland V.Istokskaia m.king D.margarone O.mcCusker P.mcKenna Z.Najmudin C.Parisuaña P.Parsons C.Spindloe D.R.Symes A.G.R.Thomas F.Treffert N.Xu C.A.J.Palmer School of mathematics and Physics Queen’s University BelfastBelfastUK Central Laser Facility STFC Rutherford Appleton LaboratoryDidcotUK Gérard mourou Center for Ultrafast Optical Science University of MichiganAnn ArborMIUSA SLAC National Accelerator Laboratory Menlo ParkCAUSA Department of Electrical and Computer Engineering University of AlbertaEdmontonABCanada The John Adams Institute for Accelerator Science Imperial College LondonLondonUK ELI Beamlines Centre Institute of PhysicsCzech Academy of SciencesDolníBˇrežanyCzech Republic Department of Applied Physics Stanford UniversityStanfordCAUSA Department of Physics SUPAUniversity of StrathclydeGlasgowUK Faculty of Nuclear Sciences and Physical Engineering Czech Technical University in PraguePragueCzech Republic Department of mechanical Engineering Stanford UniversityStanfordCAUSA Institut für Kernphysik Technische Universität DarmstadtDarmstadtGermany

The interaction of relativistically intense lasers with opaque targets represents a highly non-linear,multi-dimensional parameter *** limits the utility of sequential 1D scanning of experimental parameters for the optimization of secondary radiation,although to-date this has been the accepted methodology due to low data acquisition *** repetition-rate(HRR)lasers augmented by machine learning present a valuable opportunity for efficient source ***,an automated,HRR-compatible system produced high-fidelity parameter scans,revealing the influence of laser intensity on target pre-heating and proton generation.A closed-loop Bayesian optimization of maximum proton energy,through control of the laser wavefront and target position,produced proton beams with equivalent maximum energy to manually optimized laser pulses but using only 60%of the laser *** demonstration of automated optimization of laser-driven proton beams is a crucial step towards deeper physical insight and the construction of future radiation sources.

关键词： Bayesian optimization high repetition-rate laser-target interaction laser-driven particle acceleration proton generation

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EUROTRA:多语机器翻译的尝试

当代语言学 1985年第1期 18-21页

作者： m.king 刘敏

EUROTRA是在欧洲共同体委员会赞助下当前正在设计的一个机器翻译系统。此项设计的基本原理是由模块化设计来实现多语之间的翻译,使多语转换模块跟单语分析模块和单语生成模块严格分开。模块之间的交流是通过一个接口结构进行的。这个接... 详细信息

EUROTRA是在欧洲共同体委员会赞助下当前正在设计的一个机器翻译系统。此项设计的基本原理是由模块化设计来实现多语之间的翻译,使多语转换模块跟单语分析模块和单语生成模块严格分开。模块之间的交流是通过一个接口结构进行的。这个接口结构的定义已为参加设计的各小组所公认。这个系统的一致性是由接口结构来保证的,通过使用共同的数据结构来掌握全部加工的结果,并通过使用共同的软件来操纵数据结构。

关键词：目标语接口翻译语法文法 EUROTRA 动词词组源语荷兰语多语单语生成模块子任务语言策略名词词组语言学语言科学

Effect of rear surface fields on hot, refluxing and escaping electron populations via numerical simulations

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High Power Laser Science and Engineering 2019年第3期7卷 76-86页

作者： D.R.Rusby C.D.Armstrong G.G.Scott m.king P.mcKenna D.Neely Central Laser Facility STFCRutherford Appleton LaboratoryChiltonDidcot 0X11 OQXUK SUPA Department of PhysicsUniversity of StrathclydeGlasgow G4 ONGUK

After a population of laser-driven hot electrons traverses a limited thickness solid target,these electrons will encounter the rear surface,creating TV/m fields that heavily influence the subsequent hot-electron *** that fail to overcome the electrostatic potential reflux back into the *** electrons that do overcome the field will escape the ***,using the particle-in-cell(PIC)code EPOCH and particle tracking of a large population of macro-particles,we investigate the refluxing and escaping electron populations,as well as the magnitude,spatial and temporal evolution of the rear surface electrostatic *** temperature of both the escaping and refluxing electrons is reduced by 30%–50%when compared to the initial hot-electron temperature as a function of intensity between 1019 and 1021 W/cm^*** particle tracking we conclude that the highest energy internal hot electrons are guaranteed to escape up to a threshold energy,below which only a small fraction are able to escape the *** also examine the temporal characteristic of energy changes of the refluxing and escaping electrons and show that the majority of the energy change is as a result of the temporally evolving electric field that forms on the rear surface.

关键词： electron transport high power laser particle-in-cell simulations

Reflection of intense laser light from microstructured targets as a potential diagnostic of laser focus and plasma temperature

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High Power Laser Science and Engineering 2019年第1期7卷 10-16页

作者： J.Jarrett m.king R.J.Gray N.Neumann L.Dhl C.D.Baird T.Ebert m.Hesse A.Tebartz D.R.Rusby N.C.Woolsey D.Neely m.Roth P.mcKenna Department of Physics SUPA University of Strathclyde Institut f¨ur Kernphysik Technische Universit?t Darmstadt York Plasma Institute University of York STFC-Rutherford Appleton Laboratory Institut fur Kernphysik Technische Universit?t Darmstadt

The spatial-intensity profile of light reflected during the interaction of an intense laser pulse with a microstructured target is investigated experimentally and the potential to apply this as a diagnostic of the interaction physics is explored numerically. Diffraction and speckle patterns are measured in the specularly reflected light in the cases of targets with regular groove and needle-like structures, respectively, highlighting the potential to use this as a diagnostic of the evolving plasma surface. It is shown, via ray-tracing and numerical modelling, that for a laser focal spot diameter smaller than the periodicity of the target structure, the reflected light patterns can potentially be used to diagnose the degree of plasma expansion, and by extension the local plasma temperature, at the focus of the intense laser light. The reflected patterns could also be used to diagnose the size of the laser focal spot during a high-intensity interaction when using a regular structure with known spacing.

关键词： high power laser laser-solid interactions plasma temperature diagnosis