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Efficient guiding and focusing of intense laser pulse using periodic thin slits

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matter and Radiation at Extremes 2024年第4期9卷 29-39页

作者： L.Xu T.W.Huang K.Jiang c.n.Wu H.Peng P.c.hen R.Li H.B.Zhuo c.T.Zhou Shenzhen Key Laboratory of Ultraintense Laser and Advanced material Technology Center for Intense Laser ApplicationTechnologyand College of Engineering PhysicsShenzhen Technology UniversityShenzhen 518118People’s Republic of China

Slits have been widely used in laser-plasma interactions as plasma optical components for generating high-harmonic light and controlling laser-driven particle ***,we propose and demonstrate that periodic thin slits can be regarded as a new breed of optical elements for efficient focusing and guiding of intense laser *** fundamental physics of intense laser interaction with thin slits is studied,and it is revealed that relativistic effects can lead to enhanced laser focusing far beyond the pure diffractive focusing *** addition,the interaction of an intense laser pulse with periodic thin slits makes it feasible to achieve multifold enhancement in both laser intensity and energy transfer efficiency compared with conventional *** results provide a novel method for manipulating ultra-intense laser pulses and should be of interest for many laser-based applications.

关键词： laser pulse intense

An improved pulse coupled neural networks model for semantic IoT

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Digital communications and networks 2024年第3期10卷 557-567页

作者： Rong ma Zhen Zhang Yide ma Xiping Hu Edith c.H.ngai Victor c.m.Leung School of Information Science and Engineering Lanzhou UniversityLanzhou 730000China School of medical Technology Beijing Institute of TechnologyBeijing100081China Department of Electrical and Electronic Engineer The University of Hong KongHong Kong 999077China college of computer Science and Software Engineering Shenzhen UniversityShenzhen 518060China Department of Electrical and computer Engineering the University of British ColumbiaVancouverBC V6T 1Z4Canada

In recent years,the Internet of Things(IoT)has gradually developed applications such as collecting sensory data and building intelligent services,which has led to an explosion in mobile data ***,with the rapid development of artificial intelligence,semantic communication has attracted great attention as a new communication ***,for IoT devices,however,processing image information efficiently in real time is an essential task for the rapid transmission of semantic *** the increase of model parameters in deep learning methods,the model inference time in sensor devices continues to *** contrast,the Pulse coupled neural network(Pcnn)has fewer parameters,making it more suitable for processing real-time scene tasks such as image segmentation,which lays the foundation for real-time,effective,and accurate image ***,the parameters of Pcnn are determined by trial and error,which limits its *** overcome this limitation,an Improved Pulse coupled neural networks(IPcnn)model is proposed in this *** IPcnn constructs the connection between the static properties of the input image and the dyn.m.c.properties of the neurons,and all its parameters are set adaptively,which avoids the inconvenience of manual setting in traditional methods and improves the adaptability of parameters to different types of *** segmentation results demonstrate the validity and efficiency of the proposed self-adaptive parameter setting method of IPcnn on the gray images and natural images from the matlab and Berkeley Segmentation *** IPcnn method achieves a better segmentation result without training,providing a new solution for the real-time transmission of image semantic information.

关键词： Internet of things(IoT) Semantic information Real-time application Improved pulse coupled neural network Image segmentation

changes in children’s cardiorespiratory fitness and body mass index over the course of the cOVID‑19 pandemic:a 34‑month longitudinal study of 331 primary school children

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World Journal of Pediatrics 2024年第2期20卷 185-188页

作者： Gerald Jarnig Reinhold Kerbl mireille n.m.van Poppel Institute of Human movement Science Sport and HealthUniversity of GrazMozartgasse 148010 GrazAustria Department of Pediatrics and Adolescent medicine LKH Hochsteiermark8700 LeobenAustria

In late 2019,heavy restrictions were enforced on public activities worldwide to diminish the spread of the severe acute respiratory syndrome coronavirus 2(SARS-coV-2)virus[1].These restrictions,which included school closures and strictly limited sports and leisure opportunities,particularly impacted children and adolescents[2].Lifestyle changes in children and adolescents led to reduced physical activity levels[2,3],increased sedentary behavior[3,4],changes in eating habits,and changes in sleep habits[3].

关键词： respiratory acute children

Distinct Electrical and mechanical Responses of a cu-10Fe composite Prepared by Hot-Pressed Sintering and Post Treatment

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Acta metallurgica Sinica(English Letters) 2024年第2期37卷 255-265页

作者： X.Y.Yue S.Y.Peng X.Zhang c.n.He Y.Z.Tian Key Laboratory for Anisotropy and Texture of materials(ministry of Education) School of Materials Science and EngineeringNortheastern UniversityShenyang110819China School of materials Science and Engineering and Tianjin Key Laboratory of composite and Functional materials Tianjin UniversityTianjin300350China Research centre for metallic Wires Northeastern UniversityShenyang110819China

A cu-10wt%Fe composite was prepared through hot-pressed sintering,and the material was subsequently solution *** hot-pressed sintered and solution treated materials were rolled and *** precipitation behavior and performance changes were systematically studied by using scanning electron.m.c.oscopy and transmission electron *** contrast to the hot-pressed sintered specimen,the solution treatment significantly affects the thermal stability and properties of the cu-10wt%Fe *** cu-10wt%Fe composite was prepared after solid solution,cold rolling and aging at 773 K for 1 h,and it obtained excellent tensile strength of 494 mPa,uniform elongation of 16.3%,electrical conductivity of 51.1%IAcS and softening temperature of 838 *** for the distinct difference in thermal stability and properties between hot-pressed sintered and solution treated specimens were *** findings provide a theoretical basis for designing high-performance cu-based in-situ composites by post treatment.

关键词： cu-Fe composite Hot-pressed sintering Thermal stability Strength Electrical conductivity

Dust particle surface potential in an argonhelium plasma using the(r,q)-distribution function

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communications in Theoretical Physics 2024年第9期76卷 143-150页

作者： Bahaaudin m Raffah A A Abid Abdullah Khan Amin Esmaeili Yas Al-Hadeethi m n S Qureshi Department of Physics Faculty of Sciences King Abdulaziz University Lithography in Devices Fabrication and Development Research Group Deanship of Scientific ResearchKing Abdulaziz University Joint Laboratory of Plasma Application Technology Institute of Advanced Technology University of Science and Technology of China cAS Key Laboratory of Geospace Environment University of Science and Technology of China Department of Physics Zhejiang Normal University Department of Physics Graduate School of Science Tokyo Metropolitan University Department of Physics GC University

In this paper, the dust particle surface potential for argon-helium plasma is evaluated analytically and numerically in the context of negatively charged dust particles by employing a power-law(r, q)-distribution function. Recent studies have reported the argon-helium plasma and conducted a brief theoretical and experimental survey. To deepen our understanding further, this study aims to analyze the argon-helium plasma comprehensively using the same pattern but with the(r, q)-distribution function. For this purpose, the current balance equations are derived for electron, helium and argon ions, when these charge species attain the quasineutrality *** numerically examined the currents of plasma species for a broad range of effective distribution function parameters r and q. It is revealed that the surface potential of dust particles is significantly affected by the parameters r and q, helium ion-to-electron temperature ratio,argon ion-to-electron temperature ratio, and helium ion to argon ion number density ratio. By incorporating the multi-ion(argon-helium) species, the significance of low-temperature nonmaxwellian dusty(complex) plasma is briefly examined.

关键词： dust charge potential dusty plasma helium argon plasma non-maxwellian distribution plasma physics q distribution function r

Old-growth mixed dipterocarp forests show variable losses and gains in aboveground biomass and standing carbon over forty years

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Forest Ecosystems 2024年第1期11卷 14-23页

作者： Sisira Ediriweera champika Bandara Tithira Lakkana Shanika Jayasinghe David Woodbury Arun Dayanandan B.m.P.Singhakumara Xiangcheng mi I.A.U.n.Gunatilleke c.V.S.Gunatilleke mark SAshton Department of Science and Technology Uva Wellassa UniversityBadullaSri Lanka The Forest School Yale School of the EnvironmentYale UniversityNew HavenCT06511USA Department of Forestry and Environmental Science University of Sri JayewardenepuraNugegodaSri Lanka State Key Laboratory of Vegetation and Environmental change Institute of BotanyChinese Academy of SciencesBeijing100093China Botany Department University of PeradeniyaPeradeniyaSri Lanka

Background:no studies have documented long-term trends in aboveground biomass(AGB)for mixed-dipterocarp forests(mDF),the dominant rain forest type in tropical wet equatorial *** our study,we sought to document such trends over forty years across three sites representing lowland to lower montane ***:To do this,we established fifty 100 m×25 m plots in 1978 across three sites sampled along an elevation gradient,identified as mature old-growth *** measured trees for diameter at breast height that we identified to species and *** took wood samples to calculate species wood-specific *** re-measured plots in 1998 and again in ***:We show standing AGB for all sites combined to be 517.52 mg·ha^(-1)in 1978,but this declined by 17%over 40 years to 430.11 mg·ha^(-1).no differences exist among sites in AGB primarily because of considerable within site variation;but interactions of time with site show declines across sites were not uniform,one remained about the *** few species represented a high proportion of the AGB with the top five species comprising between 34%and 65%,depending upon site and year *** species,mesua nagassarium,represented a disproportionately large amount of AGB and decline over time,particularly at the low elevation ***:Our results are directly relevant to estimating AGB and standing carbon sequestered in *** study is the first to demonstrate varying but overall,declining trends in amounts of AGB among forests making predictions of biomass and standing carbon in mDF difficult over wide regions.

关键词： Western ghats Shorea spp. Southeast Asia Sri Lanka Tropical rain forest Wood specific gravity

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Groundwater vulnerability assessment using a GIS-based DRASTIc method in the Erbil Dumpsite area (Kani Qirzhala), central Erbil Basin, north Iraq

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Journal of Groundwater Science and Engineering 2024年第1期12卷 16-33页

作者： masoud H Hamed Rebwar n Dara marios c Kirlas Department of Earth Sciences and Petroleum College of ScienceSalahaddin University-ErbilErbilIraq Department of Petroleum Engineering College of EngineeringKnowledge UniversityErbilIraq Department of Agriculture Faculty of AgricultureForestry and Natural EnvironmentAristotle University of Thessaloniki

Groundwater vulnerability assessment is a crucial step in the efficient management of groundwater resources,especially in areas with intensive anthropogenic activities and groundwater *** the present study,the DRASTIc method was applied using Geographic Information System(GIS)to delineate groundwater vulnerability zones in the Erbil Dumpsite area,central Erbil Basin,north *** showed that the area was classified into four vulnerability classes:Very low(16.97%),low(27.67%),moderate(36.55%)and high(18.81%).The southern,south-eastern and northern parts of the study area exhibited the highest vulnerability potential,while the central-northern,northern and north-western regions displayed the lowest vulnerability ***,results of the single-parameter sensitivity analysis indicated that amongst the seven DRASTIc parameters,the unsaturated zone and the aquifer media were the most influencing *** conclustion,the correlation of 25 nitrate concentration values with the final vulnerability map,assessed using the Pearson correlation coefficient,yielded a satisfactory result of R=0.72.

关键词： DRASTIc Erbil Iraq Groundwater vulnerability assessment nitrate Pollution Sensitivity analysis

Effect of radiative loss mechanisms on FIR thermometric parameters of nd^(3+)-doped lithium tellurite glasses

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Journal of Rare Earths 2024年第7期42卷 1250-1257,I0002页

作者： c.Y.morassuti A.P.L Silva L.A.O.nunes S.m.Lima L.H.c.Andrade Optical and Photothermal Spectroscopy Group(GEOF) Center for Studies in Natural Resources(CERNA)State University of Mato Grosso do Sul(UEMS)C.P.351DouradosMSBrazil Renato Archer Information Technology center Dom Pedro I Highway(SP-65)Km 1436-Chácaras Campos dos AmaraisCampinasSPBrazil Institute of Physics of São carlos University of São PauloSão CarlosSPBrazil

nd^(3+)-doped tellurite glasses are promising materials for thermometers based on the fluorescence intensity ratio(FIR)***,at high nd^(3+)concentrations,energy transfer(ET)processes such as optical reabsorption and cross-relaxation can affect the nd^(3+)emission,which has been little explored in the ***,the present work investigated the use of nd^(3+)-doped tellurite glass(samples doped with nd^(3+)at 0.2 mol%,0.5 mol%,2.0 mol%,and 4.0 mol%)in fluorescence thermometers,in the temperature range from 299 to 371 *** results indicate a strong dependence of the FIR parameters on the nd^(3+)concentration,due to changes in the emission band profiles caused by optical reabsorption of the nd^(3+)emissions and cross-relaxation processes.A decrease of the relative sensitivity of the ratio^(4)F_(5/2)→^(4)I_(9/2)/^(4)F_(3/2)→^(4)I_(9/2)is observed for samples doped with higher amounts of nd^(3+).The maximum relative sensitivity at 299 K is 3.00%/K,which is the highest value among the reported nd^(3+)ions.

关键词： nd^(3+)-doped tellurite glass Fluorescence intensity ratio Optical thermometry Judd-Ofelt Rare earths

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In-situ study of the microstructure evolution during tension of a mg-Y-Zn-Al alloy processed by rapidly solidified ribbon consolidation technique

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Journal of magnesium and Alloys 2024年第5期12卷 2024-2040页

作者： Jeno Gubicza Kristián máthis Péter nagy Péter Jenei Zoltán Hegedus Andrea Farkas Jozef Vesely Shin-ichi Inoue Daria Drozdenko Yoshihito Kawamura Department of materials Physics Faculty of ScienceEotvos Loránd UniversityPázmány P.sétány 1/ABudapest H-1117Hungary Department of Physics of materials Faculty of Mathematics and PhysicsCharles UniversityKe Karlovu 512116 Praha 2Czech Republic Deutsches Elektronen-Synchrotron DESY Notkestr.85Hamburg 22603Germany magnesium Research center Kumamoto University2-39-1 KurokamiChuo-kuKumamoto 860-8555Japan

mg-Y-Zn-Al alloys processed by rapidly solidified ribbon consolidation(RSRc)technique exhibit an exceptional mechanical performance indicating promising application *** material has a bimodal microstructure consisting of fine recrystallized and coarse non-recrystallized grains with solute-rich stacking faults forming cluster arranged layers(cALs)and nanoplates(cAnaPs),or complete long period stacking ordered(LPSO)*** order to reveal the deformation.m.c.anisms,in-situ synchrotron X-ray diffraction line profile analysis was employed for a detailed study of the dislocation arrangement created during tension in mg-0.9%Zn-2.05%Y-0.15%Al(at%)*** uncovering the effect of the initial microstructure on the mechanical performance,additional samples were obtained by annealing of the as-consolidated specimen at 300 and 400℃ for 2 *** heat treatment at 300℃ had no significant effect on the initial microstructure,its evolution during tension and,thus,the overall deformation behavior under tensile *** the other hand,annealing at 400℃ resulted in a significant increase of the recrystallized grains fraction and a decrease of the dislocation density,leading to only minor degradation of the mechanical *** maximum dislocation density at the failure of the samples corresponding to the plastic strain of 10-25% was estimated to be about 16-20×10^(14)m^(-2).The diffraction profile analysis indicated that most dislocations formed during tension were of non-basal and pyramidal types,what was also in agreement with the Schmid factor values revealed independently from orientation *** was also shown that the dislocation-induced Taylor hardening was much lower below the plastic strain of 3% than above this value,which was explained by a model of the interaction between prismatic dislocations and cAnaPs/LPSO plates.

关键词： mg-Zn-Y-Al alloy Long period stacking ordered(LPSO)phase cluster arranged nanoplates(cAnaPs) Annealing Tension Dislocation density Hardening

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