检索结果-南通市图书馆

Numerical Method Based on Compatible Manifold Element for Thin Plate Bending

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2010年第1期23卷 100-109页

作者： zhang Zhengrong zhang xiangwei Lu Wenge Faculty of Materials and Energy Guangdong University of Technology Guangzhou 510006 China Faculty of Electromeehanical Engineering Guangdong University of Technology Guangzhou 510006 China

The typical quadrangular and triangular elements for thin plate bending based on Kirchhoff assumptions are the non- conforming elements with low computational accuracy and limitative application range in fmite element method（FEM）. Some compatible elements can be developed by the means of supplementing correction functions, increasing nodes in element or on the boundaries, expanding nodal degrees of freedom（DOF）, etc, but these elements are inconvenient to apply in practice for the high calculation complexity. In this paper, in order to overcome the defects of thin plate bending finite element, numerical manifold method（NMM） was introduced to solve thin plate bending deformation problem. Rectangular mesh was adopted as mathematical mesh to form f＇mite element cover system, and then 16-cover manifold element was proposed. Numerical manifold formulas were constructed on the basis of minimum potential energy principle, displacement boundary conditions are implemented by penalty function method, and all the element matrixes were derived in details. The 16-cover element has a simple calculation process for employing only the transverse displacement cover DOFs as the basic unknown variables, and has been proved to meet the requirements of completeness and full compatibility. As an application, the presented 16-cover element has been used to analyze bending deformation of square thin plate under different loads and boundary conditions, and the results show that numerical manifold method with compatible element, compared with finite element method, can improve computational accuracy and convergence greatly.

关键词： thin plate bending numerical manifold method compatible element 16-cover manifold element

RECONSTRUCTION OF LAYER DATA WITH DEFORMABLE B-SPLINES

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2005年第3期18卷 321-324页

作者： Cheng Siyuan zhang xiangwei Xiong Hanwei Faculty of Electromechanical Engineering Guangdong University of Technology Guangzhou 510090 China

A new B-spline surface reconstruction method from layer data based on deformable model is presented. An initial deformable surface, which is represented as a closed cylinder, is firstly given. The surface is subject to internal forces describing its implicit smoothness property and external forces attracting it toward the layer data points. And then finite element method is adopted to solve its energy minimization problem, which results a bicubic closed B-spline surface with C^2 continuity. The proposed method can provide a smoothness and accurate surface model directly from the layer data, without the need to fit cross-sectional curves and make them compatible. The feasibility of the proposed method is verified by the experimental results.

关键词： Revere engineering Surface reconstruction Deformable model Layer data

Synthesis and microwave characterization of Co-SiC core-shell powders by electroless plating

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2006年第3期25卷 216-220页

作者： zhang Haijun WU xiangwei JIA Quanli JIA Xiaolin High Temperature Ceramics Zhengzhou University Zhengzhou 450052 China

Co-SiC core-shell powders were prepared by electroless plating. Scanning electron microscopy （SEM） revealed that Co-SiC core-shell powders were of nearly sphere-like shape and were about 0.3 pan. X-ray powder diffraction （XRD） patterns showed that the cobalt powder was hexagonal crystallite. The complex dielectric constant and the complex permeability of Co-SiC core-shell powders-paraffin wax composite were measured by the rectangle wavegnide method. It showed that the dielectric loss was less than 0.1 and the magnetic loss was about 0.2 in 8.2-12.4 GHz for prepared Co-SiC core-shell comoosite oowders.

关键词： Co-SiC core-shell powders electroless plating dielectric constant permeability

Study and Application of Project Acceleration Measures Based on ACA

在线全文

学校读者我要写书评

暂无评论

Study and Application of Project Acceleration Measures Based...

Enhanced visible-light-assisted peroxymonosulfate activation over MnFe_(2)O_(4) modified g-C_(3)N_(4)/diatomite composite for bisphenol A degradation

第25届中国控制与决策会议

作者： Zhao Ping zhang xiangwei School of Civil Engineering Xi’an University of Architecture and Technology

ISBN: (纸本)9781467355322

In order to control the project schedule delay problem efficiently in actual construction, the mathematical model of Multi-process Cross-operating Acceleration Measures is built based on improvement of process implementation mode function expression and analysis of process duration-cost relationship after considering the logical and resource constraints. Then the feasible project schedule of some engineering example can be achieved by solving the mathematical model with ant colony algorithm which contains elite strategy. The final results prove that it could provide rational references for actual acceleration construction by comparing with enumeration algorithm.

关键词： Multi-modes Acceleration Measures Model Duration-cost Optimization Ant Colony Algorithm

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

International Journal of Mining Science and Technology 2021年第6期31卷 1169-1179页

作者： xiangwei zhang Chunquan Li Ting Chen Ye Tan Xiaorui Liu Fang Yuan Shuilin Zheng Zhiming Sun School of Chemical and Environmental Engineering China University of Mining and Technology(Beijing)Beijing 100083China

The MnFe_(2) O_(4)/g-C_(3) N_(4)/diatomite composites(Mn/G/D) were prepared via a facile precipitation-calcination method in this *** Mn/G/D possessed higher specific surface area,lower electron-hole pairs' recombination rate,as well as wider and stronger visible light absorption *** the synergistic effect between g-C_(3 )N_(4) and MnFe_(2) O_(4),the photogene rated electron could transfer from g-C3 N4 to MnFe_(2) O_(4),which could promote the migration of electrons as well as enhance the photocatalytic activity and peroxymonosulfate(PMS) activation ***/G/D-5% composite displayed the excellent degradation performance of bisphenol A(BPA) with the removal efficiency of 99.9% under PMS/Vis system,which was approximately 2.47 and 63.8 times as high as that of the Mn/G/D-5%/PMS and Mn/G/D-5%/Vis system,***,negative electricity derived from diatomite surface also promoted the photogenerated carriers' migration,and the degradation rate constant was around 2.4 times higher than that of MnFe_(2) O_(4)/g-C_(3) N_(4)(Mn/G).In addition,quenching experiments showed that both radical pathway(h^(+),·OH,·O_(2)^(-)and SO_(4)·^(-)) and non-radical pathway(^(1) O_(2)) were responsible for the degradation of BPA.

关键词： Bisphenol A Photocatalysis Peroxymonosulfate MnFe_(2)O_(4) g-C_(3)N_(4) Diatomite

Functionalization of diatomite with glycine and amino silane for formaldehyde removal

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2022年第2期29卷 356-367页

作者： Yonghao Di Fang Yuan Xiaotian Ning Hongwei Jia Yangyu Liu xiangwei zhang Chunquan Li Shuilin Zheng Zhiming Sun School of Chemical and Environmental Engineering China University of Mining and Technology(Beijing)Beijing 100083China

Two amino-functionalized diatomite(DE)composites modified by 3-aminopropyltriethoxysilane(APTS)or glycine(GLY)(i.e.,APTS/DE and GLY/DE)were successfully synthesized via the wet chemical method for the time-and cost-efficient removal of indoor formaldehyde(HCHO).First,the optimal preparation conditions of the two composites were determined,and then their microstructures and morphologies were characterized and *** HCHO adsorption experiments with the two types of amino-modified DE composites were also conducted to compare their adsorption *** results indicated that the pseudo-second-order kinetic and Langmuir isotherm models could well describe the adsorption process,and the maximum adsorption capacities of APTS/DE and GLY/DE prepared under optimal conditions at 20°C were 5.83 and 1.14 mg·g^(-1),*** thermodynamic parameters of the composites indicated that the adsorption process was spontaneous and *** abundant amine groups grafted on the surface of DE were derived from the Schiff base reaction and were essential for the high-efficient adsorption performance toward HCHO.

关键词： diatomite 3-aminopropyltriethoxysilane glycine adsorption formaldehyde

NEW VISUAL METHOD FOR FREE-FORM SURFACE RECONSTRUCTION

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2002年第1期15卷 35-39页

作者： Xiong Hanwei Artificial Intelligence Institute，Zhejiang University，Hangzhou 310027，China zhang xiangwei Guangdong University of Technology Artificial Intelligence Institute Zhejiang University Hangzhou 310027 China

A new method is put forward combining computer vision with computer aidedgeometric design (CAGD) to resolve the problem of free-form surface reconstruction. The surface isfirst subdivided into N-sided Gregory patches, and a stereo algorithm is used to reconstruct theboundary curves. Then, the cross boundary tangent vectors are computed through reflectance *** last, the whole surface can be reconstructed jointing these patches with G^1 continuity(tangentcontinuity). Examples on synthetic images are given.

关键词： Reverse engineering Free-form surface design Computer vision

Hierarchical assembly of highly efficient visible-light-driven Ag/g-C_(3)N_(4)/kaolinite composite photocatalyst for the degradation of ibuprofen

在线全文

学校读者我要写书评

暂无评论

Journal of Materiomics 2020年第3期6卷 582-592页

作者： Zhiming Sun xiangwei zhang Xiongbo Dong Xiaorui Liu Ye Tan Fang Yuan Shuilin Zheng Chunquan Li School of Chemical and Environmental Engineering China University of Mining and Technology(Beijing)Beijing100083China

A novel Ag/g-C_(3)N_(4)/kaolinite composite photocatalyst was fabricated for the first time through a two-step assembly strategy by employing in situ calcination and a photodeposition *** synthesized Ag/g-C_(3)N_(4)/kaolinite composite reached a higher degradation rate of ibuprofen(IBP)with a reaction rate constant of 0.0113 min^(-1) at an Ag content of 7% under visible-light irradiation,which was approximately 1.87 times that of the Ag/g-C_(3)N_(4) *** on the physicochemical properties,the enhanced photocatalytic activity was attributed to the stronger adsorption property,wider photoresponse range and more efficient separation and transfer of electron-hole ***,the incorporation of monodispersed Ag nanoparticles onto the g-C_(3)N_(4)/kaolinite sheets provided more reactive sites for the IBP *** addition,according to the EPR study and trapping experiments,it was demonstrated that holes(h^(+))should be the key reactive species.A possible pathway of IBP degradation was also proposed based on the detected ***,the results of this work may facilitate the design of a novel visible-light-driven photocatalyst with a high efficiency that is derived from a natural mineral for environmental remediation.

关键词： Photocatalyst Ag nanoparticles g-C_(3)N_(4) Kaolinite Ibuprofen Visible-light-driven

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

对流扩散方程的数值流形格式及其稳定性分析

西安交通大学学报 2010年第1期44卷 117-124页

作者：章争荣张湘伟广东工业大学材料与能源学院广州510006 广东工业大学机电工程学院广州510006

将流形方法应用于对流扩散方程的数值求解,建立了基于标准Galerkin加权余量法的定常无源对流扩散方程的数值流形格式,采用一维定常无源对流扩散方程证明了物理覆盖的覆盖函数取完全一阶多项式的标准流形格式具有绝对的数值稳定性,并通... 详细信息

将流形方法应用于对流扩散方程的数值求解,建立了基于标准Galerkin加权余量法的定常无源对流扩散方程的数值流形格式,采用一维定常无源对流扩散方程证明了物理覆盖的覆盖函数取完全一阶多项式的标准流形格式具有绝对的数值稳定性,并通过与一维对流扩散方程有限元解、精确解的对比,对该数值流形格式的稳定性进行了验证.同时,将基于四节点矩形有限单元覆盖系统的数值流形格式应用于二维平行管道中定常热对流扩散问题的数值分析.结果表明:在小的单元Pe(Pe<2)时,流形解的精度较有限元方法显著提高;在较大单元Pe条件下,一阶多项式覆盖函数的标准流形格式虽然绝对稳定,但假扩散作用显著,得到的数值解与真实结果存在较大的偏差.

关键词：对流扩散数值流形数值稳定性