检索结果-南通市图书馆

Chemical vapor deposition for perovskite solar cells and modules

在线全文

学校读者我要写书评

暂无评论

Journal of Semiconductors 2024年第4期45卷 1-4页

作者： Zhihao Tao Yuxuan Song Baochang Wang Guoqing Tong Liming Ding School of Materials Science and Engineering Hefei University of TechnologyHefei 230009China Center for Excellence in Nanoscience(CAS) Key Laboratory of Nanosystem and Hierarchical Fabrication(CAS)National Center for Nanoscience and TechnologyBeijing 100190China

Metal halide perovskites are promising materials for solar cells because of high power conversion efficiency(PCE),tun-able bandgap,high defect tolerance,long carrier diffusion length,and low-cost fabrication[1-7].The PCE for perovskite solar cells(PSCs)reaches 26.14%for single-junction cells,29.1%for perovskite/perovskite tandem cells and 33.9%for perovskite/silicon tandem cells,being comparable to that for silicon and other thin-film solar cells[8-10].Perovskite solar cells have been made by solution methods including spin-coat-ing,blade coating and printing[11,12].

关键词： perovskite blade film

Structural characteristics of electrohydrodynamic jets induced by a blade-plane actuator subjected to highly non-uniform electric fields:Parametric investigation through the particle image velocimetry techniques

在线全文

学校读者我要写书评

暂无评论

High Voltage 2023年第1期8卷 183-195页

作者： Zelu Yan Christophe Louste Philippe Traoré Jian Wu Jian'an Fang Logistics Engineering College Shanghai Maritime UniversityShanghaiChina Institut PPRIME Universitéde PoitiersPoitiersFrance Key Laboratory of Aerospace Thermophysics School of Energy Science and EngineeringHarbin Institute of TechnologyHarbinChina College of Information Science and Technology Donghua UniversityShanghaiChina

This study set out to systematically investigate the structural characteristics of plane electrohydrodynamic jets through the particle image velocimetry(PIV)techniques.Due to the wide range of applied voltages and electrode gaps under various experimental conditions,an assessment of the image quality and a statistical analysis of the velocity fields are first performed to ensure the validity of the PIV measurements,which were originally applied purely to fluid mechanics.The results indicate that the time interval between two consecutive images should be pre-adjusted to reduce the number of uncorrelated vector fields.Moreover,the minimum number of instantaneous fields should be achieved for an accurate calculation of the time-averaged fields.An equivalent electric field criterion adapted to the asymmetric electrode configuration is defined to find similarities in flow structures under different voltage and electrode gap conditions.As the applied electric field increases,three injection regimes are identified and the current increases almost linearly,indicating a large conduction current component.The decrease in charge density due to recombination proves to be relevant in all cases of this study.Analogous to the parametric analysis approach for classical jets and thermal plumes,the evolution of the coefficients of axial velocity,half-width and turbulence intensity are investigated.

关键词： plane particle blade

Comparison of roller-spreading and blade-spreading processes in powder-bed additive manufacturing by DEM simulations

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2022年第7期20卷 48-58页

作者： Jiangtao Zhang Yuanqiang Tan Xiangwu Xiao Shengqiang Jiang Institute of Manufacturing Engineering Huaqiao UniversityXiamen 361021China National&Local Joint Engineering Research Center for Intelligent Manufacturing Technology of Brittle Material Products Huaqiao UniversityXiamen 361021China School of Mechanical Engineering Xiangtan UniversityXiangtan 411105China

The roller-spreading and blade-spreading are main powder spreading methods in powder-bed additive manufacturing.The discrete element method was introduced to simulate nylon powder spreading by both roller and blade spreaders.The two spreading processes were compared from several aspects including particle flow behavior,particle contact forces,forces exerted on spreaders,particle segregation and powder layer density.It is found that powder spreading methods mainly affect the movement trajectory of particles,particle contact forces and forces exerted on spreaders.Complicated dispersion and circulation movement of particles occur inside the powder pile by roller-spreading,while particles have relatively weak dispersion by the blade-spreading.The normal force applied to the roller introduces a compacting effect on the powder pile and creates strong force chains that distribute uniformly in the powder pile.Therefore,the powder bed with higher density can be obtained by roller-spreading in thicker powder layer due to the compacting effect.The blade spreader sustains tangential force mainly,so the blade-spreading process limits its application to thicker powder layer.As the powder layer thickness increases,the roller-spreading is more sensitive to segregation index than that of the blade-spreading.The comprehensive comparison of two spreading processes provides criteria for selecting spreading methods.

关键词： Additive manufacturing Powder spreading Roller blade Discrete element metho

Alternative flexible correction forming of a blade: multipoint correction with surface measurement and deformation simulation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Manufacturing 2023年第4期11卷 587-600页

作者： Da-Wei Zhang Wen-Long Gao-Zhang Qi Zhang Xi’an Key Laboratory of Intelligent Equipment and Control School of Mechanical EngineeringXi’an Jiaotong UniversityXi’an710049People’s Republic of China

Distortion during the forging or machining processes of a blade causes problems in subsequent manufacturing. This paper proposes an alternative multipoint correction method integrated with blade measurement, determination of correcting parameters, and adjustment of the correcting die. An iterative algorithm for determining the correcting parameters is proposed. Measuring equipment combining a laser displacement sensor with multipoint flexible support is manufactured to measure the blade shape. Multipoint correcting equipment with an adaptive lower die and rapid adjustment is manufactured, and software is developed for data analysis and equipment control. The correction experiment for a rough-machined steam-turbine blade indicates that the correcting parameters can be determined after one modification based on numerical simulation, and that a rough blade that meets the allowance for finish machining can be obtained using the determined correction parameters.

关键词： blade Surface measurement Numerical simulation Multipoint correction

Field rapid detection method of wind turbine blade fixing bolt defects based on FPGA

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Optoelectronics Letters 2022年第9期18卷 541-546页

作者： HOU Yupeng ZHANG Lei WANG Yuanquan ZHAO Xiaosong FENG Guoce ZHANG Yirui School of Artificial Intelligence Hebei University of TechnologyTianjin 300130China

In order to solve the problem that blade fixing bolt cannot be detected quickly and conveniently in the field in actual production, this paper proposed a field rapid detection method of wind turbine blade fixing bolt defects based on field programmable gate array(FPGA), and Yolov4-tiny is selected as the basic algorithm. Nonetheless, the original Yolov4-tiny was not suitable for detecting small defects, so this paper improved the Yolov4-tiny to enhance the detection effect. Next, the convolutional operations in the algorithm were encapsulated into intellectual property(IP) cores by high-level synthesis(HLS) and Vivado, and parallel computation was realized using FPGA features. In the end, using Python to call the IP core and the FPGA hardware library, this paper achieved the purpose of rapid detection. Compared with traditional detection methods and other algorithms, the accuracy and speed of this method are significantly improved, which has a good application value.

关键词： hardware Python blade

Analysis of the Influence of the blade Deformation on Wind Turbine Output Power in the Framework of a Bidirectional Fluid-Structure Interaction Model

在线全文

学校读者我要写书评

暂无评论

Fluid Dynamics & Materials Processing 2023年第5期19卷 1129-1141页

作者： Ling Yuan Zhenggang Liu Li Li Ming Lin CHN Energy United Power Technology Co. Ltd.Beijing100036China School of Energy and Power Engineering Shandong UniversityJinan250061China School of Renewable Energy North China Electric Power UniversityBeijing102206China

The blades of large-scale wind turbines can obviously deform during operation,and such a deformation can affect the wind turbine’s output power to a certain extent.In order to shed some light on this phenomenon,for which limited information is available in the literature,a bidirectional fluid-structure interaction(FSI)numerical model is employed in this work.In particular,a 5 MW large-scale wind turbine designed by the National Renewable Energy Laboratory(NREL)of the United States is considered as a testbed.The research results show that blades’deformation can increase the wind turbine’s output power by 135 kW at rated working conditions.Compared with the outcomes of the simulations conducted using the model with no blade deformation,the results obtained with the FSI model are closer to the experimental data.It is concluded that the bidirectional FSI model can replicate the working conditions of wind turbines with great fidelity,thereby providing an effective method for wind turbine design and optimization.

关键词： Wind turbine fluid-structure interaction numerical simulation blade

Wu Mengchao:A blade warrior against liver cancer

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Liver Research 2022年第3期6卷 130-131页

作者： Tian Yang Qi Zhang Ming-Da Wang Feng Shen Department of Hepatobiliary Surgery Eastern Hepatobiliary Surgery HospitalSecond Military Medical University(Navy Medical University)ShanghaiChina Vaccine Research Institute of Sun Yat-sen University The Third Affiliated Hospital of Sun Yat-sen UniversityGuangzhouChina Biotherapy Center The Third Affiliated Hospital of Sun Yat-sen UniversityGuangzhouChina Zhongshan School of Medicine Sun Yat-sen UniversityGuangzhouChina

China is a big nation primarily affected by liver cancer with the number of patients with liver cancer accounting more than 50%worldwide.1,2 Dr.Wu Mengchao(August 1922-May 2021;Fig.1)has devoted almost all his energy and wisdom to fighting against liver cancer for more than half a century.Dr.Wu graduated from the Tongji University School of Medicine in 1949.In 1960,Dr.Wu worked as the chief surgeon completing the first case of surgical resection for liver cancer in China.

关键词： cancer blade devoted

A novel vibration modeling method for a rotating blade with breathing cracks

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2019年第2期62卷 333-348页

作者： XIE JingSong ZI YanYang ZHANG MingQuan LUO QinYuan State Key Laboratory for Manufacturing Systems Engineering Xi'an Jiaotong University

This paper proposes a vibration modeling method for a rotating blade with breathing cracks, considering the coupling of the centrifugal effects, the breathing effects and the crack effects. Firstly, considering the combined effects of the centrifugal stress and the bending stress, a crack breathing model for the rotating blade is proposed. Since the crack surface cannot provide the spanwise centrifugal tensile stress, an additional bending moment will be generated at the crack surface in the rotating state.Therefore, an additional bending moment caused by the centrifugal stress is then constructed. In addition, due to the discontinuity of the crack cross section, the additional stiffness caused by the centrifugal effects of the cracked blade will be smaller than that of the normal blade. Therefore, a correction coefficient of the centrifugal stiffness is built. Furthermore, based on the Lagrange equation and the assumed modal method, the vibration equation of the rotating blade with a breathing crack is established(RBC model), and a strategy is constructed for solving this vibration equation. Finally, taking the finite element model(FEM) as a reference, the vibration responses of the RBC model, the open crack model(OC) and the bilinear crack model(BC) are compared. The necessity of the RBC model is illustrated, and the accuracy of the RBC model is verified. The RBC model is a computationally efficient alternative to the finite element analysis for the rotating cracked blade. It can provide an important tool for the vibration modeling and the vibration analysis of the rotating shaft-disk-blade system with cracked blades.

关键词： vibration modeling rotating blade crack breathing model centrifugal effects

CFD simulation of single-phase flow in flotation cells:Effect of impeller blade shape,clearance,and Reynolds number

在线全文

学校读者我要写书评

暂无评论

International Journal of Mining Science and Technology 2019年第5期29卷 657-669页

作者： Manjunath Basavarajappa Sanja Miskovic Department of Metallurgical Engineering University of UtahSalt Lake City 84112United States INEOS Pigments 6752 Baymeadow DriveGlen Burnie 21061United States Norman B.Keevil Institute of Mining Engineering The University of British ColumbiaBritish Columbia V6T 1Z4Canada

A series of numerical simulations of turbulent single-phase flows are performed to understand the flow and mixing characteristics in a laboratory scale flotation tank.Four impeller blade shapes covering a wide range of surface areas and lip lengths are considered to highlight and contrast the flow behavior predicted in the impeller stream.The mean flow close to the impeller is fully characterized by considering velocity components along the axial direction at different radial locations.Normalized results suggest the development of a comparatively stronger axial velocity component for a blade design with the smallest lip length,called big-tip impeller here.Normalized turbulent kinetic energy profiles close to the impeller reveal the existence of an asymmetric trailing vortex pair.The highest turbulence kinetic energy dissipation rates are observed close to the impeller blades and stator walls where the radial jet strikes the stator walls periodically.Furthermore,liquid phase mixing in the flotation cell is studied using transient scalar tracing simulations providing mixing time data.Finally,pumping capacity and efficiency of different impeller designs are calculated based on which the impeller blade design with a rectangular blade design is found to perform most efficiently.

关键词： Flotation Impeller blade design Turbulent flow Mixing Pumping efficiency