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An Objective Approach to Generating Multi-physics Ensemble Precipitation Forecasts Based on the WRF Model

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Journal of Meteorological Research 2020年第3期34卷 601-620页

作者： Chenwei SHEN Qingyun DUAN Wei GONG Yanjun GAN Zhenhua DI Chen WANG Shiguang MIAO State Key laboratory of Earth surface Processes and Resource Ecology Faculty of Geographical ScienceBeijing Normal UniversityBeijing 100875 State Key laboratory of Hydrology–Water Resources and Hydraulic Engineering and College of Hydrology&Water Resources Hohai UniversityNanjing 210098 State Key laboratory of Severe Weather Chinese Academy of Meteorological SciencesChina Meteorological AdministrationBeijing 100081 South China Botanical Garden Chinese Academy of SciencesGuangzhou 510650 Institute of Urban Meteorology China Meteorological AdministrationBeijing 100081

Selecting proper parameterization scheme combinations for a particular application is of great interest to the Weather Research and Forecasting(WRF)model *** study aims to develop an objective method for identifying a set of scheme combinations to form a multi-physics ensemble suitable for short-range precipitation forecasting in the Greater Beijing *** ensemble is created by using statistical techniques and some *** initial sample of 90 scheme combinations was first generated by using Latin hypercube sampling(LHS).Then,after several rounds of screening,a final ensemble of 40 combinations were *** ensemble forecasts generated for both the training and verification cases using these combinations were evaluated based on several verification metrics,including threat score(TS),Brier score(BS),relative operating characteristics(ROC),and ranked probability score(RPS).The results show that TS of the final ensemble improved by 9%-33%over that of the initial *** reliability was improved for rain≤10 mm day^-1,but decreased slightly for rain>10 mm day^-1 due to insufficient *** resolution remained about the *** final ensemble forecasts were better than that generated from randomly sampled scheme *** results suggest that the proposed approach is an effective way to select a multi-physics ensemble for generating accurate and reliable forecasts.

关键词： ensemble precipitation forecast Weather Research and Forecasting(WRF)model multi-physics verification bootstrapping

Low dielectric constant and signature of ferroelectric nature in transition metal(Co,Ni,Cu)-doped Mg_(0.5)Zn_(0.5)Al_(2)O_(4)aluminates

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Journal of Advanced Dielectrics 2019年第4期9卷 63-70页

作者： M.Saleem M.Padole A.Mishra Materials Science laboratory School of Physics Vigyan BhawanDevi Ahilya University Khandwa Road CampusIndore 452001India

This paper throws light on the preparation of transition metal-doped Mg_(0.5)Zn_(0.5)Al_(2)O_(4)(x=0,0.05 and TM=Co,Ni,Cu)aluminates via solid-state reaction *** X-ray diffraction characterization analysis confirmed that all the samples have crystallized into the psuedocubic phase having space group Fd3m and were single *** incorporation of transition metals ***^(2+),Ni^(2+),Cu^(2+)in the Mg_(0.5)Zn_(0.5)Al_(2)O_(4)matrix does not result in the appearance of new peaks or any considerable shift in diffraction peaks within the limits of XRD *** infers homogeneous dispersion of dopants at the Mg-site which is attributed to nearly same ionic radii of the dopants to that of Mg-site in Mg 0:5 Zn0:5 Al 2 O *** structure,bonding nature and hence the spinel formation were verified through Raman scattering *** compositional verification was carried out via energy dispersive analysis of X-rays(EDAX).The surface morphology and hence the microstructural studies were carried out using field emission scanning electron microscopy(FESEM).The synthesized Mg_(0.5)Zn_(0.5)Al_(2)O_(4)(x=0,0.05 and TM=Co,Ni,Cu)aluminate samples were tested for polarization studies keeping their insulating nature into consideration and they displayed a sign of well-behaved P-E loop.

关键词： Nanoparticles structure morphology polarization

A theoretical study on chemical ordering of 38-atom trimetallic Pd-Ag-Pt nanoalloys

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Chinese physics B 2020年第7期29卷 548-554页

作者： Songül Taran Ali Kemal Garip Haydar Arslan Department of physics Duzce UniversityDuzce 81620Turkey Department of physics Zonguldak Bulent Ecevit UniversityZonguldak 67100Turkey

In this study,truncated octahedron(TO)structure is selected for further analysis and we focus on 38-atom Pd-Pt-Ag trimetallic *** best chemical ordering structures of PdnAg32-nPt6 trimetallic nanoalloys are obtained at Gupta *** structures with the lowest energy at Gupta level are then re-optimized by density functional theory(DFT)relaxations and DFT results confirm the Gupta level calculations with small shifts on bond lengths indicating TO structure is favorable for 38-atom of PdnAg32-nPt6 trimetallic *** DFT excess energy analysis shows that Pd8Ag24Pt6 composition has the lowest excess energy value in common with excess energy analysis at Gupta *** Pd8Ag24Pt6 composition,eight Pd atoms are central sites of 8(111)hexagonal facets of TO,24 Ag atoms locate on surface,and 6 Pt atoms locate at the core of the *** is also obtained that all of the compositions except Pd18Ag14Pt6 and Pd20Ag12Pt6 exhibit a octahedral Pt ***,it is observed that there is a clear tendency for Ag atoms to segregate to the surface and also Pt atoms prefer to locate at core due to order parameter(R)variations.

关键词： nanoalloys chemical ordering optimization density functional theory(DFT)

High temperature thermal behaviour modeling of large-scale fused silica optics for laser facility

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Chinese physics B 2012年第6期21卷 329-334页

作者：于景侠贺少勃向霞袁晓东郑万国吕海兵祖小涛 Department of Applied physics University of Electronic Science and Technology of China Research Centre of Laser Fusion China Academy of Engineering Physics

High temperature annealing is often used for the stress control of optical ***,weight and viscosity at high temperature may destroy the surface morphology,especially for the large-scale,thin and heavy optics used for large laser *** is necessary to understand the thermal behaviour and design proper support systems for large-scale optics at high *** this work,three support systems for fused silica optics are designed and simulated with the finite element *** the analysis of the thermal behaviours of different support systems,some advantages and disadvantages can be *** results show that the support with the optical surface vertical is optimal because both pollution and deformation of optics could be well controlled during annealing at high *** process of the optics irradiated by CO2 laser is also *** can be concluded that high temperature annealing can effectively reduce the residual ***,the effects of annealing on surface morphology of the optics are *** creep is closely related to the residual stress and strain *** the region with large residual stress,the creep is too large and probably increases the deformation gradient which may affect the laser beam propagation.

关键词： numerical simulation support systems large-scale fused silica high temperature

Effects of thickness & shape on localized surface plasmon resonance of sexfoil nanoparticles

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Chinese physics B 2017年第1期26卷 508-513页

作者： Yan Chen Xianchao Liu Weidong Chen Zhengwei Xie Yuerong Huang Ling Li College of physics and Electronic Engineering Sichuan Normal University Chengdu 610101 China State Key laboratory of Electronic Thin Films and Integrated Devices School of Optoelectronic Information University of Electronic Science and Technology Chengdu 610054 China

Localized surface plasmon （LSPR） resonance and sensing properties of a novel nanostructure （sexfoil nanoparticle） are studied using the finite-difference time-domain method. For the sandwich sexfoil nanoparticle, the calculated extinction spectrum shows that with the thickness of the dielectric layer increasing, long-wavelength peaks blueshift, while short- wavelength peaks redshift. Strong near-field coupling of the upper and lower metal layers leads to electric and magnetic field resonances; as the thickness increases, the electric field resonance gradually increases, while the magnetic field resonance decreases. The obtained refractive index sensitivity and figure of merit are 332 nm/RIU and 3.91 RIU^-1, respectively. In order to obtain better sensing ability, we further research the LSPR character of monolayer Ag sexfoil nanoparticle. After a series of trials to optimize the thickness and shape, the refractive index sensitivity approximates 668 nm/RIU, and the greatest figure of merit value comes to 14.8 RIU^-1.

关键词： sexfoil nanoparticle localized surface plasmon resonance extinction properties LSPR sensors

Symmetry-enforced three-dimensional Dirac phononic crystals

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Light(Science & Applications) 2020年第1期9卷 1641-1646页

作者： Xiangxi Cai Liping Ye Chunyin Qiu Meng Xiao Rui Yu Manzhu Ke Zhengyou Liu Key laboratory of Artificial Micro-Structures and Nano-Structures of Ministry of Education and School of physics and Technology Wuhan University430072 WuhanChina Institute for Advanced Studies Wuhan University430072 WuhanChina

Dirac semimetals,the materials featuring fourfold degenerate Dirac points,are critical states of topologically distinct *** gapless topological states have been accomplished by a band-inversion mechanism,in which the Dirac points can be annihilated pairwise by perturbations without changing the symmetry of the ***,we report an experimental observation of Dirac points that are enforced completely by the crystal symmetry using a nonsymmorphic three-dimensional phononic ***,our Dirac phononic crystal hosts four spiral topological surface states,in which the surface states of opposite helicities intersect gaplessly along certain momentum lines,as confirmed by additional surface *** novel Dirac system may release new opportunities for studying elusive(pseudo)and offer a unique prototype platform for acoustic applications.

关键词： Dirac topological forced

Enhancement in photovoltaic properties of Nd:SnS films prepared by low-cost NSP method

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Rare Metals 2022年第5期41卷 1661-1670页

作者： S.Sebastian I.Kulandaisamy A.M.S.Arulanantham S.Valanarasu A.Kathalingam Mohd.Shkir Salem AlFaify PG&Research Department of physics Arul Anandar CollegeKarumathurMadurai 625514India Millimeter Wave Innovation Technology Research Center(MINT) Dongguk University-SeoulSeoul 04620Republic of Korea Advanced Functional Materials&Optoelectronics laboratory(AFMOL) Department of PhysicsFaculty of ScienceKing Khalid UniversityAbha 9004Saudi Arabia

The inner transition metal(ITM) neodymium(Nd)-doped tin sulfide(Nd:SnS) thin films with various Nd concentrations were coated by nebulizer spray pyrolysis(NSP) technique at 350℃. All the coated films were analyzed for their structural, optical and photoelectrical properties. X-ray diffractometer(XRD) study showed(111) direction as the highly preferred orientation with orthorhombic crystal structure for all the films. The intensity of the peaks was found to increase until 5 at% Nd doping and then reduced for higher(7 at% Nd) doping concentration. Atomic force microscopic(AFM) images of the films proclaimed an increase in the surface and line roughness of the films by increasing Nd *** analysis on the films showed a variation in energy gap from 2.05 to 1.69 eV when the doping concentration increased from 0 at% to 7 at%. At 5 at% Nd doping, the photoluminescence(PL) spectra displayed a single strong emission peak at 723.1 nm with enhanced intensity corresponding to near-band-edge emission. All the SnS thin films exhibited p-type behavior with the lowest resistivity of ~ 4.311 Ω·cm and high carrier concentrations of ~ 1.441 × 10^(17)cm^(-3) for 5 at% Nd doping level as observed from Hall effect studies. Furthermore, fluorinedoped tin oxide(FTO)/n-CdS/p-Nd:SnS hetero-junction solar cells were prepared and the current–voltage curve in dark and light condition was obtained for the device. An efficiency of 0.135% was observed for the solar cell fabricated with 5 at% Nd-doped SnS thin film.

关键词： Rare earth doping Neodymium SnS thin films Nebulizer spray Optical studies Solar cells

Improvement of a Snow Albedo Parameterization in the Snow–Atmosphere–Soil Transfer Model:Evaluation of Impacts of Aerosol on Seasonal Snow Cover

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Advances in Atmospheric Sciences 2017年第11期34卷 1333-1345页

作者： Efang ZHONG Qian LI Shufen SUN Wen CHEN Shangfeng CHEN Debashis NATH Center for Monsoon System Research Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China University of Chinese Academy of Sciences Beijing 100049 China State Key laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

The presence of light-absorbing aerosols （LAA） in snow profoundly influence the surface energy balance and water budget. However, most snow-process schemes in land-surface and climate models currently do not take this into consider- ation. To better represent the snow process and to evaluate the impacts of LAA on snow, this study presents an improved snow albedo parameterization in the Snow-Atmosphere-Soil on snow. Specifically, the Snow, Ice and Aerosol Radiation Transfer （SAST） model, which includes the impacts of LAA （SNICAR） model is incorporated into the SAST model with an LAA mass stratigraphy scheme. The new coupled model is validated against in-situ measurements at the Swamp Angel Study Plot （SASP）, Colorado, USA. Results show that the snow albedo and snow depth are better reproduced than those in the original SAST, particularly during the period of snow ablation. Furthermore, the impacts of LAA on snow are esti- mated in the coupled model through case comparisons of the snowpack, with or without LAA. The LAA particles directly absorb extra solar radiation, which accelerates the growth rate of the snow grain size. Meanwhile, these larger snow particles favor more radiative absorption. The average total radiative forcing of the LAA at the SASP is 47.5 W m-2. This extra radiative absorption enhances the snowmelt rate. As a result, the peak runoff time and ＂snow all gone＂ day have shifted 18 and 19.5 days earlier, respectively, which could further impose substantial impacts on the hydrologic cycle and atmospheric processes.

关键词： light-absorbing aerosols snow albedo SAST SNICAR

Brightness of Blue/Violet Luminescent Nano-Crystalline AZO and IZO Thin Films with Effect of Layer Number:For High Optical Performance

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Chinese physics Letters 2016年第5期33卷 80-83页

作者： Panagiota KORAL Songül FAT VAROL Michael KOMPITSAS Mihaela GIRTAN School of Mechanical Engineering National Technical University of Athens National Hellenic Research Foundation Theoretical and Physical Chemistry Institute Giresun University Faculty of EngineeringEnergy Systems Engineering Photonics laboratory Angers University

From different reports, it （AZO） and indium-doped including usage areas. We nanocrystalline films with is realized that there is a need to consider all sides of aluminum-doped zinc oxide zinc oxide （IZO） thin films with their optical, luminescence and surface properties establish an assessment to carry out further information to summarize AZO and IZO impact of the layer number.

关键词： of in is AZO ZnO Brightness of Blue/Violet Luminescent Nano-Crystalline AZO and IZO Thin Films with Effect of Layer Number:For High Optical Performance for that with