检索结果-南通市图书馆

A hybrid original approach for prediction of the aerodynamic coefficients of an ATR-42 scaled wing model

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2016年第1期29卷 41-52页

作者： Abdallah Ben Mosbah Ruxandra Mihaela Botez Thien my Dao Department of Automated Production Engineering Ecole de Technologie SuperieureUniversity of QuebecLaboratory of Applied Research in Active ControlsAvionics and AeroServoElasticity LARCASEMontrealQuebec H3C-1K3Canada Department of Mechanical Engineering Ecole de Technologie SuperieureUniversity of QuebecMontrealQuebec H3C-1K3Canada

A new approach for the prediction of lift, drag, and moment coefficients is presented. This approach is based on the support vector machines （SVMs） methodology and an optimization meta-heuristic algorithm called extended great deluge （EGD）. The novelty of this approach is the hybridization between the SVM and the EGD algorithm. The EGD is used to optimize the SVM parameters. The training and validation of this new identification approach is realized using the aerodynamic coefficients of an ATR-42 wing model. The aerodynamic coefficients data are obtained with the XFoil software and experimental tests using the Price-Paidoussis wind tunnel. The predicted results with our approach are compared with those from the XFoil software and experimental results for different flight cases of angles of attack and Mach numbers. The main pur- pose of this methodology is to rapidly Predict aircraft aerodynamic coefficients.

关键词： Aerodynamic coefficients Estimation Extended great deluge Metaheuristic Model identification Optimization Support vector machines Wind tunnel tests

Periodic oscillation of quantum diffusion in coupled one-dimensional systems

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2022年第4期65卷 95-103页

作者： JinYi Jiang YanYan Lu Chao Wang Rémy Mosseri JianXin Zhong Hunan Key Laboratory of Micro-Nano Energy Materials and Devices School of Physics and OptoelectronicsXiangtan UniversityXiangtan 411105China Laboratoire de Physique Théorique de la Matière Condensée Sorbonne UniversitéCentre National de la Recherche ScientifiqueParis F-75005France

We analytically show that quantum diffusion in the coupled system composed of two identical chains exhibits a well-defined periodic oscillation in both transverse and longitudinal directions with a frequency determined by the interchain hopping strength, no matter whether the chains are periodic or non-periodic. We illustrate the result through numerical work on the coupled periodic chains and the quasiperiodic Aubry-Andre-Harper(AAH) chains with various modulations of onsite potentials supporting extended, critical, and localized states. We further numerically show that quantum diffusion in the coupled chains of different degrees of disorder W exhibits an exponential decay oscillation similar to the behavior of an underdamped harmonic oscillator, with a decay time inversely proportional to the square of W and a slight frequency change proportional to the square of W. Moreover, quantum diffusions in the coupled systems composed of two different chains are numerically studied, including periodic/disordered chains, periodic/AAH chains, and two different AAH chains, which exhibit the same behavior of underdamped periodic oscillation if the onsite potential difference between two chains is smaller than the interchain hoping *** of this universal periodic oscillation is a result of spectral splitting of the iso-spectra of two chains determined by interchain hopping, independent of system size, boundary condition, and intrachain onsite potentials. Because the oscillation frequency and spreading distance of wavepacket can be tuned separately by interchain hopping and intrachain potentials, the periodic oscillation of quantum diffusion in coupled chains is expected to find applications in control of quantum states and in designing nanoscale quantum devices.

关键词： quantum diffusion periodic oscillation localization coupled systems

同方期刊数据库

ELECTRON　TRANSFER　AGENT　DEPENDENCY　OF　MONOOXYGENATION　OF　CYCLOHEXANE　CATALYZED　BY　SILICA　IMMOBILIZED　N，N＇－BIS［2－（BENZIMIDAZOLYLMETHYL）］AMINO　FERROUS　ACETATE　COMPLEX

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 1996年第1期7卷 47-50页

作者： Wang, TJ Ma, ZH Huang, my Jiang, YY ACAD SINICA INST CHEM BEIJING 100080 PEOPLES R CHINA

Silica the N, N'-bis[-2-(benzimidazolylmethyl)]amino-ferrous acetate complexes (Ⅳ)catalyzed monooxygenation of cyclohexane to cyclohexanol with the turnover muber(equrvalent C%= 11. 2)under mild *** methylene bule is the most effective electron transfer agent which can also regulate products distribution. The iron content of the polymer-supported complexes, the redox potentials and the concentration of methylene blue greatly affect the activity and selectivity of the complex (Ⅳ).

关键词： AGENT DEPENDENCY BIS ACETATE

Visualisation and personalisation of multi-representations city models

在线全文

学校读者我要写书评

暂无评论

International Journal of Digital Earth 2020年第5期13卷 627-644页

作者： Jérémy Gaillard Adrien Peytavie Gilles Gesquiére LIRIS UMR CNRS 5205Univ LyonVilleurbanneFrance Oslandia LyonFrance

City models have a wide variety of uses that require different kind of data representation or data *** a dynamic model that enables picking the right representations(meshes,volumetric data,point cloud,etc.)can prove useful to adapt an application to each user’s *** this paper,we present an original method to create personalised visualisations of 3D city models on the *** organising the server data in a hierarchy of tiles,we are able to generate personalised models based on the user’s *** preferences take the shape of a set of rules that apply to each tile or city object and allow the user to choose which representation of the object to use depending on its position or semantic information(classification,height,etc.).Our method is designed around existing standards,guaranteeing the interoperability of the produced models.

关键词： 3D visualisation web geospatial city model

Acoustic measurements of models of military style supersonic nozzle jets

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

Chinese Journal of Aeronautics 2014年第1期27卷 23-33页

作者： Ching-Wen Kuo Jérémy Veltin Dennis K.McLaughlin Department of Aerospace Engineering The Pennsylvania State UniversityUniversity Park TNO Science and Industry

Modern military aircraft jet engines are designed with variable-geometry nozzles to provide optimal thrust in different operating conditions, depending on the flight envelope. How- ever, acoustic measurements for such nozzles are scarce, due to the cost involved in making full- scale measurements and the lack of details about the exact geometries of these nozzles. Thus the present effort at Pennsylvania State University （PSU） in partnership with GE Aviation and the NASA Glenn Research Center is aiming to study and characterize the acoustic field produced by supersonic jets issuing from converging-diverging military style nozzles, and to identify and test promising noise reduction techniques. An equally important objective is to develop methodology for using data obtained from small- and moderate-scale experiments to reliably predict the full-scale engine noise. The experimental results presented show reasonable agreement between small-scale and medium-scale jets, as well as between heated jets and heat-simulated ones.

关键词： Aeroacoustics Acoustic noise measurement Jet noise Jets Nozzle Supersonic flow

CFD simulations of gas-solid flow in an industrial-scale circulating fluidized bed furnace using subgrid-scale drag models

在线全文

学校读者我要写书评

暂无评论

Particuology 2015年第1期13卷 66-75页

作者： Srujal Shah Kari my?h?nen Sirpa Kallio Timo Hypp?nen Department of Energy Technology Lappeenranta University of Technology VTT Technical Research Centre of Finland

Mesoscale flow structures such as clusters and streamers of particles are characteristic features of gas-solid flow in fluidized beds. Numerical simulations of gas-solid flows for industrial-scale fluidized beds are often performed using the Eulerian description of phases. An accurate prediction of this type of flow structure using the Eulerian modeling approach requires a sufficiently fine mesh resolution. Because of the long computational time required when using fine meshes, simulations of industrial-sized units are usually conducted using coarse meshes, which cannot resolve the mesoscale flow structures. This leads to an overestimation of the gas-solid drag force and a false prediction of the flow field. For these cases, a cor- rection must be formulated for the gas-solid drag. We have simulated a large-scale circulating fluidized bed furnace using different gas-solid drag models and compared the model results with measurements.

关键词： Circulating fluidized bed Computational fluid dynamics Two-fluid model Drag correlation Modeling

Crafting chirality in three dimensions via a novel fabrication technique for bound states in the continuum metasurfaces

在线全文

学校读者我要写书评

暂无评论

Light(Science & Applications) 2024年第3期13卷 390-392页

作者： Zaid Haddadin Anna my Nguyen Lisa V.Poulikakos Department of Electrical&Computer Engineering University of California San DiegoLa JollaCAUSA Department of Mechanical&Aerospace Engineering University of California San DiegoLa JollaCAUSA Program of Materials Science&Engineering University of California San DiegoLa JollaCAUSA

An additional deposition step was added to a multi-step electron beam lithographic fabrication process to unlock the height dimension as an accessible parameter for resonators comprising unit cells of quasi-bound stat... 详细信息

关键词： dimensions dimension intrinsic

Fuzzy MCDM for Improving the Performance of Agricultural Supply Chain

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

Computers, Materials & Continua 2022年第11期73卷 4003-4015页

作者： Le Thi Diem my Chia-Nan Wang Nguyen Van Thanh Department of Industrial Engineering and Management National Kaohsiung University of Science and TechnologyKaohsiung CityTaiwan Faculty of Commerce Van Lang UniversityHo Chi Minh CityVietnam

Fertilizer industry in Vietnam and globally have entered the saturation *** the growth rate slowing down,this poses challenges for the development impetus of the fertilizer industry in the next *** fact,over the past few decades,Vietnam’s crop industry has abused excessive investment in chemical fertilizers,with organic fertilizers are rarely used or not at all,limiting crop productivity,increasing pests and *** develop sustainable agriculture,Vietnam’s crop industry must limit the use of chemical fertilizers,increase the use of environmentally friendly organic and natural mineral fertilizers to produce clean agricultural products which is ***,it is necessary to consider and choose the right supplier to ensure the goal of sustainable *** Fuzzy Analytic Hierarchy Process(SF-AHP),and the combinative distance-based assessment(CODAS)are new Multicriteria Decision Making(MCDM)method which can be used to solve supplier selection *** paper uses an effective solution based on a combined the concept of triple bottom line(TBL),SF-AHP and CODAS approach to help agriculture companies that need to select the best fertilizer *** research can support supply chain managers to achieve supply chain systems that reduce not only sourcing costs,but also develop sustainable agriculture.

关键词： Fuzzy theory MCDM model fertilizer agricultural supply chain optimization

Assessment and adjustment of sea surface salinity products from Aquarius in the southeast Indian Ocean based on in situ measurement and my Ocean modeled data

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

Acta Oceanologica Sinica 2016年第3期35卷 54-62页

作者： XIA Shenzhen KE Changqing zhou Xiaobing ZHANG Jie Jiangsu Provincial Key Laboratory of Geographic Information Science and Technology Nanjing UniversityNanjing 210023China Collaborative Innovation Center of South China Sea Studies Nanjing 210023China Collaborative Innovation Center of Novel Software Technology and Industrialization Nanjing 210023China Department of Geophysical Engineering Montana Tech of the University of MontanaButteMT 59701USA The First Institute of Oceanography State Oceanic AdministrationQingdao 266061China

The in situ sea surface salinity（SSS） measurements from a scientific cruise to the western zone of the southeast Indian Ocean covering 30°-60°S, 80°-120°E are used to assess the SSS retrieved from Aquarius（Aquarius SSS）.Wind speed and sea surface temperature（SST） affect the SSS estimates based on passive microwave radiation within the mid- to low-latitude southeast Indian Ocean. The relationships among the in situ, Aquarius SSS and wind-SST corrections are used to adjust the Aquarius SSS. The adjusted Aquarius SSS are compared with the SSS data from my Ocean model. Results show that：（1） Before adjustment： compared with my Ocean SSS, the Aquarius SSS in most of the sea areas is higher; but lower in the low-temperature sea areas located at the south of 55°S and west of 98°E. The Aquarius SSS is generally higher by 0.42 on average for the southeast Indian Ocean.（2） After adjustment： the adjustment greatly counteracts the impact of high wind speeds and improves the overall accuracy of the retrieved salinity（the mean absolute error of the Zonal mean is improved by 0.06, and the mean error is-0.05 compared with my Ocean SSS）. Near the latitude 42°S, the adjusted SSS is well consistent with the my Ocean and the difference is approximately 0.004.

关键词： Aquarius sea surface salinity(SSS) in situ SSS my Ocean comparison analysis southeast Indian Ocean