检索结果-南通市图书馆

CLOSED-FORM SOLUTIONS FOR ELASTOPLASTIC PURE BENDING OF A CURVED BEAM WITH MATERIAL INHOMOGENEITY

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 Mechanica Solida Sinica 2014年第1期27卷 54-64页

作者： Guojuan nie Zheng zhong School of Aerospace Engineering and Applied Mechanics Tongji University

The elastoplastic pure bending problem of a curved beam with material inhomo- geneity is investigated based on Tresca＇s yield criterion and its associated flow rule. Suppose that the material is elastically isotropic, ideally elastic-plastic and its elastic modulus and yield limit vary radially according to exponential functions. Closed-form solutions to the stresses and radial displacement in both purely elastic stress state and partially plastic stress state are presented. Numerical examples reveal the distinct characteristics of elastoplastic bending of a curved beam composed of inhomogeneous materials. Due to the inhomogeneity of materials, the bearing capac- ity of the curved beam can be improved greatly and the initial yield mode can also be dominated. Closed-form solutions presented here can serve as benchmark results for evaluating numerical solutions.

关键词： elastoplastic pure bending curved beam inhomogeneous materials closed-form solutions

Comprehensive interpretation of the Sedongpu glacier-related mass flows in the eastern Himalayan syntaxis

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2022年第9期19卷 2469-2486页

作者： ZHANG Xiao-peng HU Kai-heng LIU Shuang nie Yong HAN yun-zhong Institute of Mountain Hazards and Environment Chinese Academy of SciencesChengdu 610041China University of Chinese Academy of Sciences Beijing 100049China Beijing Institute of Spacecraft System Engineering Beijing 100094China

Glacier-related mass flows(GMFs)in the high-mountain cryosphere have become more frequent in the last decade,e.g.,the 2018 Sedongpu(SDP)GMFs in the *** forcing,thermal perturbation and heavy rainfall are common triggers of the *** the exact role of seimic forcing in the GMF formation is poorly known due to scarity of observational data of real *** the evolution processes of the GMFs and the detachment of the trunk glacier in SDP are reconstructed by using remote sensing techniques,including feature-tracking of multi-source optical satellite imagery and visual *** reconstruction demonstrates that the high frequency of GMF events in SDP after the Milin earthquake on 18 November 2017 was mainly attributed to the earthquake-induced glacial stress changes and *** post-earthquake velocity of the trunk glacier is about three times of that in December 2016 and December *** median glacier-surface velocity raised to 0.32 m d-1between November 2017 and June 2018,being 14%-77%higher than that of pre-earthquake,which is initiated by the seismic forcing and then aggravated by additional loading of ice/rock avalanches,infiltration of liquid water,progressively crevassed glacier,and local compressional *** surge motion of the trunk glacier resulted from high temperature and heavy precipitation between July and September *** infer that the trunk glacier is more sensitive to the thermal perturbation after the Milin earthquake,which is the predominant cause in sudden surge *** findings reveal comprehensive mechanisms of quakeinduced,low-angle,glacial detachment and multisource-driven GMF in the Himalayas.

关键词： Glacier-related mass flow(GMF) Milin earthquake Glacial speedup Glacier detachment Ice/rock avalanche

AXISYMMETRIC BENDING OF TWO-DIRECTIONAL FUNCTIONALLY GRADED CIRCULAR AND ANNULAR PLATES

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2007年第4期20卷 289-295页

作者： Guojun nie Zheng zhong School of Aerospace Engineering and Applied Mechanics Tongji University Shanghai 200092 China

Assuming the material properties varying with an exponential law both in the thick- ness and radial directions, axisymmetric bending of two-directional functionally graded circular and annular plates is studied using the semi-analytical numerical method in this paper. The deflections and stresses of the plates are presented. Numerical results show the well accuracy and convergence of the method. Compared with the finite element method, the semi-analytical nu- merical method is with great advantage in the computational efficiency. Moreover, study on ax- isymmetric bending of two-directional functionally graded annular plate shows that such plates have better performance than those made of isotropic homogeneous materials or one-directional functionally graded materials. Two-directional functionally graded material is a potential alternative to the one-directional functionally graded material. And the integrated design of materials and structures can really be achieved in two-directional functionally graded materials.

关键词： two-directional functionally graded materials circular and annular plates axisym-metric bending semi-analytical numerical method integrated design

Schwarz lemma from a Kähler manifold into a complex Finsler manifold

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2022年第8期65卷 1661-1678页

作者： Jun nie Chunping zhong School of Mathematical Sciences Xiamen UniversityXiamen 361005China

Suppose that M is a complete Kähler manifold such that its holomorphic sectional curvature is bounded from below by a constant and its radial sectional curvature is also bounded from *** that N is a strongly pseudoconvex complex Finsler manifold such that its holomorphic sectional curvature is bounded from above by a negative *** this paper,we establish a Schwarz lemma for holomorphic mappings f from M into *** applications,we obtain a Liouville type rigidity result for holomorphic mappings f from M into N,as well as a rigidity theorem for bimeromorphic mappings from a compact complex manifold into a compact complex Finsler manifold.

关键词： Schwarz lemma Kähler manifold complex Finsler manifold holomorphic sectional curvature

Enantioselective reductive conjugate alkenylation of α,β-enones with keto alkenyl acetates by nickel catalysis

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2025年第01期 157-162页

作者： Rong-De He yun-Lei Luo Qiu-Quan Pan Qi-Wei Yao Xing-zhong Shu State Key Laboratory of Applied Organic Chemistry College of Chemistry and Chemical Engineering Lanzhou University

Reactions involving alkenyl acetates offer cost-effective and environmentally friendly routes for alkene synthesis, yet their asymmetric variant remains elusive. Concurrently, asymmetric conjugate alkenylation predominantly centered on nucleophilic addition using alkenyl–M. This manuscript presents an asymmetric reductive conjugate alkenylation reaction involving alkenyl acetates. The method facilitates the enantioselective addition of keto alkenyl groups to α,β-enones, resulting in the formation of unsaturated diketones—a class of useful structural motifs that are challenging to access otherwise. The use of electron-rich Pyroxy ligand is essential for achieving both high reaction efficiency and enantioselectivity.

关键词：

Corrosion Resistance of AZ91 Mg Alloy Modified by High-Current Pulsed Electron Beam

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 Metallurgica Sinica(English Letters) 2019年第2期32卷 218-226页

作者： Peng-Peng Wu Kun-Kun Deng Kai-Bo nie zhong-zhong Zhang Shanxi Key Laboratory of Advanced Magnesium-Based Materials College of Materials Science and EngineeringTaiyuan University of Technology

The high-current pulsed electron beam(HCPEB) treatment with current density 6 J/cm^2 was applied on AZ91 Mg alloy to improve its corrosion resistance. Results showed that the net-like Mg_(17)Al_(12) disappeared on the surface of AZ91 Mg alloy after irradiation by HCPEB, which was instead of supersaturated Al element on the surface. Nevertheless, the application of HCPEB also led to the formation of crater-like and groove-like structures as well as micro-cracks on the surface of AZ91 Mg alloy. After HCPEB treatment by 3, 5 and 10 pulses, the AZ91 Mg alloy exhibited better corrosion ***, the increasing amount of micro-cracks reduced the anti-corrosive properties of AZ91 Mg alloy as the pulse increased to 20 and 30.

关键词： High-current pulsed electron beam(HCPEB) Corrosion resistance Electrochemical impedance spectroscopy(EIS) AZ91 Mg alloy Microstructure

Convergence analysis for complementary-label learning with kernel ridge regression

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics(A Journal of Chinese Universities) 2024年第3期39卷 533-544页

作者： nie Wei-lin WANG Cheng XIE zhong-hua School of Mathematics and Statistics Huizhou UniversityHuizhou 516007China School of Computer Science and Engineering Huizhou UniversityHuizhou 516007China

Complementary-label learning(CLL)aims at finding a classifier via samples with complementary *** data is considered to contain less information than ordinary-label *** transition matrix between the true label and the complementary label,and some loss functions have been developed to handle this *** this paper,we show that CLL can be transformed into ordinary classification under some mild conditions,which indicates that the complementary labels can supply enough information in most *** an example,an extensive misclassification error analysis was performed for the Kernel Ridge Regression(KRR)method applied to multiple complementary-label learning(MCLL),which demonstrates its superior performance compared to existing approaches.

关键词： multiple complementary-label learning partial label learning error analysis reproducing kernel Hilbert spaces

Narrow Band Gap and Room-temperature Ferromagnetism in KNb1-xFexO3-δ

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Physics 2017年第1期30卷 97-102,I0002页

作者： Dan nie Jiang Zhang Wen-ji Deng Xi Chen zhong-quan Mao Ling-yun Tang Department of Physics South China University of Technology Guangzhou 510641 China

We have investigated the structure, optical and magnetic properties of ferroelectric KNb1-xFe2O3-δ （x=0, 0.01, 0.03, 0.05, 0.10, 0.15, 0.20, 0.25） synthesized by a traditional solid-state reaction method. According to the X-ray diffraction and the results of Rietveld refinement, all the samples maintain orthorhombic distorted perovskite structures with Amm2 space group without any secondary phase, suggesting the well incorporation of Fe ions into the KNbO3 matrix. With the increase of Fe concentration, the band gap of each sample is decreased gradually, which is much smaller than the 3.18 eV band gap of pure KNbO3. Through X-ray photoelectron spectrum analysis, the increased density of oxygen vacancy and Fe ions may be responsible for the observed decrease in band gap. Compared with the pure KNbO3, Fe doped samples exhibit room-temperature weak ferromagnetism. The ferromagnetism in KNb1-xFexO3-δ with low-concentration dopants （x=0.01-0.10） can be attributed to the bound magnetic polaron mediated exchange. The enhancement of magnetism for the high-concentration （x=0.10-0.20） doped samples may arise from the further increase of magnetic Fe ions.

关键词： KNbO3 Dope Optical property Magnetic property Bound magnetic polaron

Relationship Between Producer Services Developing Level and Urban Hierarchy——A Case Study of Zhujiang River Delta

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 Geographical Science 2008年第1期18卷 1-8页

作者： zhong yun YAN Xiaopei Institute of Hong Kong Macao ＆ SEZs Economy Jinan University Guangzhou 510632 China Center for Urban ＆ Regional Studies SUN Yat-Sen University Guangzhou 510275 China

As the Central Place Theory indicates, the centricity of a central city can influence the extension of its ser- vice. Since the service industry in the theory is mostly consumer services, it is worth studying the relationship between the producer services and the centricity of the city in the service society with producer services becoming a more im- portant part of the service industry. The paper takes the case of the Zhujiang (Pearl) River Delta (PRD), a developed region in China, to study the relationship between the developing level of producer services and the urban hierarchy. Based on the analysis about the spatial difference of the producer services in the nine cities of the PRD, and the divi- sion of the nine cities according to some economic indices, it is shown that there is a correlation between the develop- ing level of producer services and the urban hierarchy. Furthermore, two deductions about the future status of the pro- ducer services in the city and the location of the producer services in a large region can be made from this correlation between the developing level of producer services and the urban hierarchy.

关键词： producer services urban hierarchy correlativity Zhujiang (Pearl) River Delta (PRD)