检索结果-南通市图书馆

Applied Mathematics and Mechanics(English Edition) 2023年第1期44卷 53-72页

作者： Zheng GONG Yinxiao ZHANG Ernian pan chao ZHANG School of Aeronautics Northwestern Polytechnical UniversityXi'an 710072China Joint International Research Laboratory of Impact Dynamics and Its Engineering Applications Xi'an 710072China Civil Engineering and Institute of Pioneer Semiconductor Innovation Yang Ming Chiao Tung UniversityHsinchu 30010TaiwanChina School of Civil Aviation Northwestern Polytechnical UniversityXi'an 710072China

In this paper,by defining a general potential energy for the multiphase coupled multiferroics and applying the minimum energy principle,the coupled governing equations are *** system of equations is then discretized as a general three-dimensional(3D)finite element(FE)model based on the COMSOL *** validating the formulation,it is then applied to the analysis and design of the common sandwich structure of multiferroics *** the typical static loading,the effects of general lateral boundary conditions,material grading,nonlinearity,as well as polarization orientation on the composites are *** the magneto-electro-elastic(MEE)sandwich made of piezoelectric BaTiO_(3)and magnetostrictive CoFe_(2)O_(4)with different stacking sequences,various interesting features are observed which should be very helpful for the design of high-performance multiphase composites.

关键词： multiferroics sandwich composite magneto-electro-elastic(MEE)material multilayered plate nonlinear behavior

Development of machine learning multi-city model for municipal solid waste generation prediction

在线全文

学校读者我要写书评

暂无评论

Frontiers of Environmental Science & Engineering 2022年第9期16卷 89-98页

作者： Wenjing Lu Weizhong Huo Huwanbieke Gulina chao pan School of Environment Tsinghua UniversityBeijing 100084China

Integrated management of municipal solid waste(MSW)is a major environmental challenge encountered by many *** support waste treatment/management and national macroeconomic policy development,it is essential to develop a prediction *** this motivation,a database of MSW generation and feature variables covering 130 cities across China is *** on the database,advanced machine learning(gradient boost regression tree)algorithm is adopted to build the waste generation prediction model,i.e.,*** the model development process,the main influencing factors on MSW generation are identified by weight *** selected key influencing factors are annual precipitation,population density and annual mean temperature with the weights of 13%,11%and 10%,*** WGMod shows good performance with R^(2)=*** prediction on MSW generation in Beijing and Shenzhen indicates that waste generation in Beijing would increase gradually in the next 3–5 years,while that in Shenzhen would grow rapidly in the next 3 *** difference between the two is predominately driven by the different trends of population growth.

关键词： Municipal solid waste Machine learning Multi-cities Gradient boost regression tree

DETECTION OF CAVITATION IN CENTRIFUGAL PUMP BY VIBRATION METHODS

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2008年第5期21卷 46-49页

作者： NI Yongyan yuan Shouqi pan Zhongyong yuan Jianping Research Center of Fluid Machinery Engineering and Technology Jiangsu University Zhenjiang 212013 China

For the purpose of detecting the cavitation of centrifugal pump onsite and real time, the vibration signals on varied operation conditions of both cavitation and non-cavitation obtained through acceleration sensors were analyzed. When cavitation occurs, the cavities near the leading edge of the blade will appear periodic oscillating, which will induce quasi-synchronous vibration. The frequency of the quasi-synchronous vibration symmetrically appears on the two sides of the blade passing frequency, by which the cavitation incipiency can be detected. During the developing process of the cavitation, as the severe complexity of the unsteady flow, it is very difficult to detect the development of cavitation by classical analysis methods. Fractal method of Higuchi is successfully used for detecting the incipiency, fully development of cavitation and the development between them.

关键词： Centrifugal pump Cavitation Vibration Detection

Improvement in Cr Nanoparticle Content in Ni-Cr Film by Co-deposition with Combined Surfactant HPB and CTAB

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2017年第10期30卷 999-1007页

作者： Li-Juan Qin yuan-chao Huang Laboratory for Corrosion and Protection Institute of Metal ResearchChinese Academy of Sciences College of Material Science and Engineering University of Science and Technology of China

The effects of single surfactant hexadecylpyridinium bromide（HPB） and cetyltrimethylammonium bromide（CTAB） and the combination of HPB and CTAB on the Cr nanoparticle content in the Ni-Cr film prepared by codeposition were investigated. Single HPB/CTAB addition inhibited the oxidation and amorphous transformation of the Cr nanoparticles in the plating bath and effectively stabilized the Cr nanoparticles content at approximately 10 mass% as a function of time. Moreover, the combination of HPB and CTAB formed a cylindrical micelle structure on the Cr nanoparticle surface, which prompted the formation of a layer of NiCr2O4. As a result, the Cr nanoparticle content increased sharply to 20 mass%.

关键词： Co-deposition Ni-Cr film Cr nanoparticle content HPB CTAB

Slip in Couette flow with pressure gradient:Theoretical and experimental investigation of hydrodynamic characteristics considering slip effect

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2020年第1期32卷 107-115页

作者： Xin Zhao chao Wei Shi-hua yuan Science and Technology on Vehicle Transmission Laborator Bejing Institute of TechnologyBeijing 10081China

A new slip velocity model based on molecular potential theory and macro-force analysis,which is applied in Couette flow with pressure gradient,is built *** model is validated by later being introduced in hydrodynamic system to predict film distribution,which shows a good agreement with experimental data obtained from multi-beam intensity-based tests with Fe and Cu ball materials under accurate controlled temperature,load and different wall *** show that the slip length for Fe case is ignorable so it seems like no slip,but for Cu case,the slip length is large to make 20%discrepancy with no slip simulation and also behaves ***,during the experimental cases when both Fe and Cu ball velocities rise from-133 mm/s to 1330 mm/s,the slip velocity changes its direction with entrainment velocity and thus contributes to first enhance and then diminish the hydrodynamic film,but due to slip length on Cu case varying largely than that on Fe case,the film from Cu case and from Fe case has a clear cross-point between uh=80 mm/s and uh=220 m m/s(ub is the ball speed).The results above support strongly that Cu surface will lead to stronger slip than Fe case because of its smaller solid-liquid interaction,and obviously slip will influence hydrodynamic characteristics prominently.

关键词： Slip Couette flow with pressure gradient hydrodynamic characteristic

Recent Advances in the Genetic Dissection of Neural Circuits in Drosophila

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

Neuroscience Bulletin 2019年第6期35卷 1058-1072页

作者： chao Guo Yufeng pan Zhefeng Gong Key Laboratory of Developmental Genes and Human Disease of the Ministry of Education of China Institute of Life SciencesSoutheast UniversityNanjing 210096China Department of Neurobiology Key Laboratory of Medical Neurobiology of the Ministry of Health of ChinaKey Laboratory of NeurobiologyZhejiang University School of MedicineHangzhou 310058China

Nervous systems endow animals with cognition and behavior. To understand how nervous systems control behavior, neural circuits mediating distinct functions need to be identified and characterized. With superior genetic manipulability, Drosophila is a model organism at the leading edge of neural circuit analysis. We briefly introduce the state-of-the-art genetic tools that permit precise labeling of neurons and their interconnectivity and investigating what is happening in the brain of a behaving animal and manipulating neurons to determine how behaviors are affected. Brain-wide wiring diagrams, created by light and electron microscopy, bring neural circuit analysis to a new level and scale. Studies enabled by these tools advances our understanding of the nervous system in relation to cognition and behavior.

关键词： Drosophila Neural circuit Neuroanatomy Neurogenetics Systems neuroscience

Prospect and Reality of Concentration Gradient Cathode of Lithium-ion Batteries

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Structural Chemistry 2020年第1期39卷 11-15,1页

作者： LIU Tong-chao pan Feng AMINE Khalil Chemical Sciences and Engineering Division Argonne National LaboratoryArgonneIL 60439USA School of Advanced Materials Peking UniversityShenzhen Graduate SchoolShenzhen 518055China Material Science and Engineering Stanford UniversityStanfordCA 94305USA

Li[NixMnyCoz]O2 cathodes are currently the most practicable materials in the timing of developing high-performance rechargeable batteries for next-generation *** the ever-growing demand for energy density,a significant breakthrough has been achieved by the controllable concentration design forming core-shell and concentration gradient structures to push Li[NixCoyMnz]O2 toward higher energy density,longer lifetime and ***,we review the recent progress on advanced concentration gradient cathode ***,we prospect that this novel approach will continuously extend its advantages in developing extremely fast charging and Co-free cathode materials in the near future.

关键词： lithium-ion batteries Li[NixMnyCoz]O2 core-shell structure concentration gradient structure

A novel solution of rectangular composite laminates under oblique low-velocity impacts

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2024年第12期45卷 2165-2182页

作者： Yinxiao ZHANG Zheng GONG Ernian pan chao ZHANG School of Aeronautics Northwestern Polytechnical University Joint International Research Laboratory of Impact Dynamics and Its Engineering Applications School of Civil Aviation Northwestern Polytechnical University Department of Civil Engineering College of Engineering Disaster Prevention and Water Environment Research Center Institute of Pioneer Semiconductor Innovation Yang Ming Chiao Tung University

An analytical solution for the responses of composite laminates under oblique low-velocity impacts is presented for a cross-ply, orthotropic, and rectangular plate under oblique low-velocity impacts. The plate is under simply-supported edge conditions, and the dynamic displacement field is expressed in a mixed form by in-plane double Fourier series and cubic polynomials through the thickness as 12 variables for each layer. A system of modified Lagrange equations is derived with all interface constraints. The Hertz and Cattaneo-Mindlin theories are used to solve for the normal and tangential contact forces during the impacts. By further discretizing in the time domain, the oblique impact problem is solved iteratively. While the numerical results clearly show the influence of impact velocity, stacking sequence, mechanical parameters, and geometric parameters, the proposed analytical approach could serve as a theoretical basis for the laminate analysis and design when it is under low-velocity impacts.

关键词： 74B05 analytical model composite laminate modified Lagrange equation O343 oblique impact three-dimensional (3D) displacement field

Dynamics of low-speed streak evolution and interaction in laminar boundary layer

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2014年第5期30卷 636-645页

作者： Si-chao Deng Chong pan Jin-Jun Wang Fluid Mechanics Key Laboratory of Ministry of Education Beihang University

The present paper presents an experimental effort on the regeneration process of two low-speed laminar streaks in a zero-pressure-gradient laminar boundary layer. Two vertical thin wires separated by a spanwise distance of 30 mm are used to introduce disturbances of two rolls of transitional Karmain vortex street to the downstream boundary layer. Both hydrogen bubble visualization and particle image velocimetry （PIV） measurement show that two lowspeed streaks are induced through leading-edge receptivity process. As these streaks develop in the downstream, two additional low-speed streaks begin to appear outboard of the flank of the original two, together with complex dynamics of streak splitting and merging. A flow pattern of four streaks aligned along the spanwise direction occurs finally in the far downstream. It is found that besides the mechanisms of streak breakdown, the streak interaction is also an important factor characterizing the instability of low speed streaks and their regeneration process.

关键词： Low-speed streak - Boundary layer transition Streak reproduction

Image-based 3D model retrieval using manifold learning

在线全文

学校读者我要写书评

暂无评论

Frontiers of Information Technology & Electronic Engineering 2018年第11期19卷 1397-1408页

作者： pan-pan MU San-yuan ZHANG Yin ZHANG Xiu-zi YE Xiang pan College of Computer Science and Technology Zhejiang University College of Mathematics and Information Science Wenzhou University College of Computer Science and Technology Zhejiang University of Technology

We propose a new framework for image-based three-dimensional(3D) model retrieval. We first model the query image as a Euclidean point. Then we model all projected views of a 3D model as a symmetric positive definite(SPD) matrix, which is a point on a Riemannian manifold. Thus, the image-based 3D model retrieval is reduced to a problem of Euclid-to-Riemann metric learning. To solve this heterogeneous matching problem, we map the Euclidean space and SPD Riemannian manifold to the same high-dimensional Hilbert space, thus shrinking the great gap between them. Finally, we design an optimization algorithm to learn a metric in this Hilbert space using a kernel trick. Any new image descriptors, such as the features from deep learning, can be easily embedded in our framework. Experimental results show the advantages of our approach over the state-of-the-art methods for image-based 3D model retrieval.

关键词： Model retrieval Euclidean space Riemannian manifold Hilbert space Metric learning