检索结果-南通市图书馆

THE HEATING FIELD IN AN AsYMMETRIC HuRRICANE -PART I:sCALE analysis

在线全文

学校读者我要写书评

暂无评论

Advances in Atmospheric sciences 1985年第03期2卷 402-413页

作者： T.N.Krishnamurti,盛剑 Department of Meteorology Florida state university u.s.a Department of Meteorology Florida state university u.s.a

A closed system of equations describing an asymmetric disturbance in cylindrical geometry is expanded about a small parameter. The small parameter describes the ratio of the magnitude of divergence in the boundary layer to that above that layer. A low order system describes a gradient wind balance in the radial direction and is quasi-symmetric with respect to the pressure and temperature fields. This system can be solved as an inverse problem for a mature steady state hurricane. The procedure entails asking the questions what structure and heating distributions are required to maintain a given asymmetric distribution of the tangential velocity (i. e. the angular momentum) in steady state. The method of characteristics enables us to solve for the vertical motion. That in turn determines the radial motion from the mass continuity equation. Application of the hydrostatics to the cylindrical thermal wind equation determines the pressure and the thermal fields and finally the required heating fields are dedu

关键词： THE HEATING FIELD IN AN AsYMMETRIC HuRRICANE PART I

Proton irradiation-induced cracking and microstructural defects in uN and (u,Zr)N composite fuels

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Materiomics 2024年第4期10卷 906-918页

作者： Elina Charatsidou Maria Giamouridou Andrea Fazi Gyula Nagy Diogo Ribeiro Costa sarmad Naim Katea Mikael Jolkkonen Gunnar Westin Mattias Thuvander Daniel Primetzhofer Pär Olsson KTH Royal Institute of Technology StockholmSweden Chalmers university of Technology GothenburgSweden uppsala university UppsalaSweden Westinghouse Electric sweden AB VästeråsSweden Höganäs sweden AB HöganäsSweden

Proton irradiation with a primary ion energy of 2 MeV was used to simulate radiation damage in uN and(u,Zr)N fuel *** pellets,nominally at room temperature,were irradiated to peak levels of 0.1,1,10 dpa and 100.0 dpa resulting in a peak hydrogen concentration of at most 90 at.%.Microstructure and mechanical properties of the samples were investigated and compared before and after *** irradiation induced an increase in hardness,whereas a decrease in Young’s modulus was observed for both *** characterization revealed irradiation-induced cracking,initiated in the bulk of the material,where the peak damage was deposited,propagating towards the ***,transmission electron microscopy was used to study irradiation *** loops and fringes were identified and observed to increase in density with increasing dose *** high density of irradiation defects and hydrogen implanted are proposed as the main cause of swelling and consequent sample cracking,leading simultaneously to increased hardening and a decrease in Young's modulus.

关键词： Proton irradiation uranium nitride spark plasma sintering Irradiation induced cracking simulated burn-up structure Composite nuclear fuels

Performance Limits and Advancements in single 2D Transition Metal Dichalcogenide Transistor

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano-Micro Letters 2024年第12期16卷 134-188页

作者： Jing Chen Ming-Yuan sun Zhen-Hua Wang Zheng Zhang Kai Zhang shuai Wang Yu Zhang Xiaoming Wu Tian-Ling Ren Hong Liu Lin Han Institute of Marine science and Technology Shandong UniversityQingdao 266237ShandongPeople’s Republic of China school of Integrated Circuits and Beijing National Research Center for Information science and Technology(BNRist) Tsinghua UniversityBeijing 100084People’s Republic of China BNRist Tsinghua UniversityBeijing 100084People’s Republic of China state Key Laboratory of Crystal Materials Shandong UniversityJinan 250100ShandongPeople’s Republic of China shenzhen Research Institute of shandong university Shenzhen 518057People’s Republic of China shandong Engineering Research Center of Biomarker and Artificial Intelligence Application Jinan 250100People’s Republic of China

Two-dimensional(2D)transition metal dichalcogenides(TMDs)allow for atomic-scale manipulation,challenging the conventional limitations of semiconductor *** capability may overcome the short-channel effect,sparking significant advancements in electronic devices that utilize 2D *** the dimension and performance limits of transistors based on 2D TMDs has gained su.s.antial *** review provides a comprehensive investigation into these limits of the single 2D-TMD *** delves into the impacts of miniaturization,including the reduction of channel length,gate length,source/drain contact length,and dielectric thickness on transistor operation and *** addition,this review provides a detailed analysis of performance parameters such as source/drain contact resistance,subthreshold swing,hysteresis loop,carrier mobility,on/off ratio,and the development of p-type and single logic *** review details the two logical expressions of the single 2D-TMD logic transistor,including current and *** also emphasizes the role of 2D TMD-based transistors as memory devices,focusing on enhancing memory operation speed,endurance,data retention,and extinction ratio,as well as reducing energy consumption in memory devices functioning as artificial *** review demonstrates the two calculating methods for dynamic energy consumption of 2D synaptic *** review not only summarizes the current state of the art in this field but also highlights potential future research directions and *** underscores the anticipated challenges,opportunities,and potential solutions in navigating the dimension and performance boundaries of 2D transistors.

关键词： Two-dimensional transistors Dimension limits Performance limits Memory devices Artificial synapses

Prioritizing Indicators for Rapid Response in Global Health security: A Bayesian Network Approach

在线全文

学校读者我要写书评

暂无评论

INTERNATIONAL JOuRNAL OF DIsAsTER RIsK sCIENCE 2024年第4期15卷 536-551页

作者： Qazi, Abroon simsekler, Mecit Can Emre Al-Mhdawi, M. K. s. Amer univ sharjah Sch Business Adm Sharjah 26666 U Arab Emirates Khalifa univ sci & Technol Dept Management Sci & Engn Abu Dhabi 127788 U Arab Emirates Teesside univ Sch Comp Engn & Digital Technol Middlesbrough TS1 3BX England

This study explored a Bayesian belief networks (BBNs) approach, developing two distinct models for prioritizing the seven indicators related to the "rapid response to and mitigation of the spread of an epidemic" category within the context of both the specific category and the Global Health security Index (GHs index). utilizing data from the 2021 GHs index, the methodology involves rigorous preprocessing, the application of the augmented naive Bayes algorithm for structural learning, and k-fold cross-validation. Key findings show unique perspectives in both BBN models. In the mutual value of information analysis, "linking public health and security authorities" emerged as the key predictor for the "rapid response to and mitigation of the spread of an epidemic" category, while "emergency preparedness and response planning" assumed precedence for the GHs index. sensitivity analysis highlighted the critical role of "emergency preparedness and response planning" and "linking public health and security authorities" in extreme performance states, with "access to communications infrastructure" and "trade and travel restrictions" exhibiting varied significance. The BBN models exhibit high predictive accuracy, achieving 83.3% and 82.3% accuracy for extreme states in "rapid response to and mitigation of the spread of an epidemic" and the GHs index, respectively. This study contributes to the literature on GHs by modeling the dependencies among various indicators of the rapid response dimension of the GHs index and highlighting their relative importance based on the mutual value of information and sensitivity analyses.

关键词： Bayesian belief networks Global health security Indicators Mitigation Policy implications Rapid response RIsK DIsEAsE

self-propelled Leidenfrost droplets on femtosecond-laser-induced surface with periodic hydrophobicity gradient

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Extreme Manufacturing 2024年第2期6卷 502-509页

作者： Bohong Li Lan Jiang Xiaowei Li Zhipeng Wang Peng Yi Laser Micro/Nano Fabrication Laboratory School of Mechanical EngineeringBeijing Institute of TechnologyBeijingPeople’s Republic of China Beijing Institute of Technology Chongqing Innovation Center ChongqingPeople’s Republic of China Yangtze Delta Region Academy of Beijing Institute of Technology JiaxingPeople’s Republic of China

The controllable transfer of droplets on the surface of objects has a wide application prospect in the fields of microfluidic devices,fog collection and so *** Leidenfrost effect can be utilized to significantly reduce motion ***,the use of 3D structures limits the widespread application of self-propulsion based on Leidenfrost droplets in microelectromechanical *** manipulate Leidenfrost droplets,it is necessary to create 2D or quasi-2D *** this study,femtosecond laser is applied to fabricate a surface with periodic hydrophobicity gradient(sPHG),enabling directional self-propulsion of Leidenfrost *** field analysis within the Leidenfrost droplets reveals that the vapor layer between the droplets and the hot surface can be modulated by the sPHG,resulting in directional propulsion of the inner *** viscous force between the gas and liquid then drives the droplet to move.

关键词： self-propelled Leidenfrost droplets periodic hydrophobicity gradient femtosecond laser fabrication

Estimating the grain size of microgranular material using laser-induced breakdown spectroscopy combined with machine learning algorithms

在线全文

学校读者我要写书评

暂无评论

Plasma science and Technology 2024年第5期26卷 129-137页

作者：张朝李亚举杨光辉曾强李小龙陈良文钱东斌孙对兄苏茂根杨磊张少锋马新文 Key Laboratory of Atomic and Molecular Physics and Functional Materials of Gansu Province College of Physics and Electronic EngineeringNorthwest Normal UniversityLanzhou 730070People’s Republic of China Advanced Energy science and Technology Guangdong LaboratoryHuizhou 516000People’s Republic of China Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000People’s Republic of China university of the Chinese Academy of sciences Beijing 100049People’s Republic of China school of Nuclear science and Technology University of the Chinese Academy of SciencesBeijing 100049People’s Republic of China

Recent work has validated a new method for estimating the grain size of microgranular materials in the range of tens to hundreds of micrometers using laser-induced breakdown spectroscopy(LIBs).In this situation,a piecewise univariate model must be constructed to estimate grain size due to the complex dependence of the plasma formation environment on grain *** the present work,we tentatively construct a unified calibration model suitable for LIBs-based estimation of those grain ***,two unified multivariate calibration models are constructed based on back-propagation neural network(BPNN)algorithms using feature selection strategies with and without considering prior *** detailed analysis of the performances of the two multivariate models,it was found that a unified calibration model can be successfully constructed based on BPNN algorithms for estimating the grain size in the range of tens to hundreds of *** was also found that the model constructed with a priorguided feature selection strategy had better prediction *** study has practical significance in developing the technology for material analysis using LIBs,especially when the LIBs signal exhibits a complex dependence on the material parameter to be estimated.

关键词： laser-induced breakdown spectroscopy machine learning randomly packed microgranular materials

Age-of-Information-Aware Federated Learning

在线全文

学校读者我要写书评

暂无评论

Journal of Computer science & Technology 2024年第3期39卷 637-653页

作者：徐殷肖明军吴晨吴杰周津锐孙贺 student Member CCF 1.School of Computer Science and TechnologyUniversity of Science and Technology of ChinaHefei 230026China suzhou Institute for Advanced Research University of Science and Technology of ChinaSuzhou 215123China school of Data science University of Science and Technology of ChinaHefei 230026China Department of Computer and Information sciences Temple UniversityPhiladelphiaPA 19122U.S.A. CCF IEEE

Federated learning(FL)is an emerging privacy-preserving distributed computing paradigm,enabling numerous clients to collaboratively train machine learning models without the necessity of transmitting clients’private datasets to the central *** most existing research where the local datasets of clients are assumed to be unchanged over time throughout the whole FL process,our study addresses such scenarios in this paper where clients’datasets need to be updated periodically,and the server can incentivize clients to employ as fresh as possible datasets for local model *** primary objective is to design a client selection strategy to minimize the loss of the global model for FL loss within a constrained *** this end,we introduce the concept of“Age of Information”(AoI)to quantitatively assess the freshness of local datasets and conduct a theoretical analysis of the convergence bound in our AoI-aware FL *** on the convergence bound,we further formulate our problem as a restless multi-armed bandit(RMAB)***,we relax the RMAB problem and apply the Lagrangian Dual approach to decouple it into multiple ***,we propose a Whittle’s Index Based Client selection(WICs)algorithm to determine the set of selected *** addition,comprehensive simulations su.s.antiate that the proposed algorithm can effectively reduce training loss and enhance the learning accuracy compared with some state-of-the-art methods.

关键词： federated learning Age of Information restless multi-armed bandit Whittle’s index

Wavelength calibration and spectral analysis of vacuum ultraviolet spectroscopy in EAsT

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Plasma science and Technology 2024年第8期26卷 37-43页

作者：计华健张洪明吕波 Cheonho BAE 何梁林子超尹相辉沈永才戴舒宇 Institute of Plasma Physics Chinese Academy of SciencesHefei 230031People’s Republic of China science Island Branch Graduate SchoolUniversity of Science and Technology of ChinaHefei 230031People’s Republic of China College of Electrical Engineering University of South ChinaHengyang 421001People’s Republic of China school of Physics and Materials Engineering Hefei Normal UniversityHefei 230601People’s Republic of China school of Physics Dalian University of TechnologyDalian 116024People’s Republic of China

A vacuum ultraviolet(VuV)spectroscopy with a focal length of 1 m has been engineered specifically for observing edge impurity emissions in Experimental Advanced superconducting Tokamak(EAsT).In this study,wavelength calibration for the VuV spectroscopy is achieved utilizing a zinc *** grating angle and charge-coupled device(CCD)position are carefully calibrated for different wavelength *** wavelength calibration of the VuV spectroscopy is crucial for improving the accuracy of impurity spectral data,and is required to identify more impurity spectral lines for impurity transport *** spectra of EAsT plasmas have also been obtained in the wavelength range of 50–300 nm with relatively high spectral *** is found that the impurity emissions in the edge region are still dominated by low-Z impurities,such as carbon,oxygen,and nitrogen,albeit with the application of fulltungsten divertors on the EAsT tokamak.

关键词： vacuum ultraviolet spectroscopy wavelength calibration impurity spectra

CONTINuOus AND DIsCRETE N-CONVEX APPROXIMATIONs

在线全文

学校读者我要写书评

暂无评论

analysis in Theory and Applications 1992年第4期8卷 28-34页

作者： D.Legg D.Townsend Indiana university-Purdue university U.S.A

We show that the best L_p-approximant to continuous functions by n-convex functions is the limit of discrete n-convex *** techniques of the proof are then used to show the existence of near interpolants to discrete n-... 详细信息

关键词： CONTINuOus AND DIsCRETE N-CONVEX APPROXIMATIONs