检索结果-南通市图书馆

Meso-Scale Modeling for Effective Properties in Continuous Fiber-Reinforced Composites by State-Based Peridynamics

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2021年第5期34卷 729-742页

作者： Xiang li yin yu Zhongcheng Mu y.L.Hu Aerospace Structure Research Center School of Aeronautics and AstronauticsShanghai Jiao Tong UniversityShanghai200240China School of Aeronautics and Astronautics Shanghai Jiao Tong UniversityShanghai200240China

This study demonstrates a homogenization approach via a modified state-based peridynamic(PD)method to predict the effective elastic properties of composite materials with periodic *** procedure of modeling the PD unit cell(UC)of continuous fiber-reinforced composite is *** boundary conditions are derived and implemented through the Lagrange multiplier method.A matrix-dominated approach for modeling the interphase properties between dissimilar materials is *** periodicity and continuity assumptions are employed to determine the stress and strain fields,as well as the effective elastic *** PD-UCs of square and hexagonal packs as well as the 0/90 laminate microstructure are modeled and compared with the analytical,numerical and experimental results from the *** agreement of predicted effective properties can be *** other PD homogenization approaches,the effective material properties can be directly and individually obtained from simple loading conditions.

关键词： State-based peridynamics Composites Meso-scale Unit Cell Homogenization

Magnetic and Transport Properties of Mn_(0.98)Cr_(0.02)Te Epitaxial Films Grown on Al_2O_3 Substrates

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

Journal of Materials Science & Technology 2014年第2期30卷 103-106页

作者： Z.H.Wang D.y.Geng J.li y.B.li Z.D.Zhang Sheny.ng National Laboratory for Materials Science Institute of Metal Researchand International Centre for Materials PhysicsChinese Academy of Sciences Changchun Institute of Optics Fine Mechanics and PhysicsChinese Academy of Sciences

The epitaxial Mno0.98Cr0.02Te films on single crystal Al2O3 （0001） substrates were prepared by pulsed laser deposition. The X-ray diffraction and scanning electron microscopy results showed that the good continuous epitaxial film was obtained with substrate temperature of 500 ℃. When the substrate temperature reached 700 ℃, the film was island growth and the manganese oxides phase appeared. The temperature dependence of both the magnetization and electrical resistance showed a sharp rise at around 60 K due to the magnetoelastic coupling. The temperature dependence of the electrical resistance of Mno0.98Cr0.02Te provided evidence for a transition from the metallic to semiconducting state at 305 K due to the spin disorder scattering with a large contribution from the influence of magnon drag.

关键词： Magnetic properties Mno0.98Cr0.02Te films X-ray diffraction Epitaxial film

Low-rank matrix recovery with total generalized variation for defending adversarial examples

在线全文

学校读者我要写书评

暂无评论

Frontiers of Information Technology & Electronic Engineering 2024年第3期25卷 432-445页

作者： Wen li Hengyou WAng lianzhi HUO Qiang HE linlin CHEN Zhiquan HE Wing W.y.ng School of Science Beijing University of Civil Engineering and ArchitectureBeijing 100044China School of Computer Science and Engineering South China University of TechnologyGuangzhou 510006China Aerospace Information Research Institute Chinese Academy of SciencesBeijing 100094China Guangdong Key Laboratory of Intelligent Information Processing Shenzhen 518060China Institute of Big Data Modeling and Technology Beijing University of Civil Engineering and ArchitectureBeijing 100044China

Low-rank matrix decomposition with first-order total variation(TV)regularization exhibits excellent performance in exploration of image *** advantage of its excellent performance in image denoising,we apply it to improve the robustness of deep neural ***,although TV regularization can improve the robustness of the model,it reduces the accuracy of normal samples due to its *** our work,we develop a new low-rank matrix recovery model,called LRTGV,which incorporates total generalized variation(TGV)regularization into the reweighted low-rank matrix recovery *** the proposed model,TGV is used to better reconstruct texture information without *** reweighted nuclear norm and li-norm can enhance the global structure ***,the proposed LRTGV can destroy the structure of adversarial noise while re-enhancing the global structure and local texture of the *** solve the challenging optimal model issue,we propose an algorithm based on the alternating direction method of *** results show that the proposed algorithm has a certain defense capability against black-box attacks,and outperforms state-of-the-art low-rank matrix recovery methods in image restoration.

关键词： Total generalized variation Low-rank matrix Alternating direction method of multipliers Adversarial example

An Efficient and Convenient Cyclization Method for the Synthesis of Flavans

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 1998年第9期9卷 805-807页

作者： Hou, LM Huang, CS Cen, W li, y li, yL Lanzhou Univ Inst Organ Chem Lanzhou 730000 Peoples R China Lanzhou Univ Natl Lab Appl Organ Chem Lanzhou 730000 Peoples R China Qingdao Univ Dept Chem Qingdao 266071 Peoples R China

A convenient cyclization method for the flavans synthesis is described. BF3 was used for the first time as an efficient catalyst to effect the cyclization of 1,3-diarylpropan-1-ols.

关键词： flavans cyclization synthesis

De Novo Design and Synthesis of Four-Helix Bundle Peptides

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 1996年第9期7卷 809-811页

作者： li, XQ Miao, ZW Luo, y li, CX Tang, yQ BEIJIng UNIV DEPT CHEMBEIJING 100871PEOPLES R CHINA

Two peptides (li22 and li29) designed to form four-helix bundle were synthesized by stepwise solid phase peptide synthesis (SPPS) using Fmoc strategy, purified by reversed phase high performance liquid chromatography ... 详细信息

关键词： Design Four De Novo Design and Synthesis of Four-Helix Bundle Peptides

Inokosterone Is a Potential Drug Target of Estrogen Receptor 1 in Rheumatoid Arthritis Patients:Analysis from Active Ingredient of Cyathula Officinalis

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Integrative Medicine 2021年第10期27卷 767-773页

作者： MO Ji-hao XIE Han-kun ZHOU ye-mian ng Sihan-benjamin li Shao-xia WAng Lei Department of Medical Laboratory Luoyang Orthopedic Hospital of Henan ProvinceOrthopedic Institute of Henan ProvinceLuoyangHenan Province(471002)China Miller School of Medicine University of Miami(33136)MiamiFLUSA Institute of Technical Biology&Agriculture Engineering Hefei Institutes of Physical ScienceChinese Academy of SciencesHefei(230031)China Eatobe Pte.limited(573969) Singapore

Objective:To elucidate the active compounds and the molecular mechanism of Cyathula Off/c/na//s as a drug treatment for rheumatoid arthritis(RA).Methods:The target genes of active ingredients from Cyathula Officinalis were obtained from bioinformatics analysis tool for the molecular mechanism of traditional Chinese *** protein-protein interaction between the target genes were analyzed using STRIng and *** transcriptome of RA patients compared to healthy people(GSE121894)were analyzed using R program package *** relative expression of the target genes was obtained from the RNA-seq *** molecular docking analyses were processed based on the molecular model of estrogen receptor 1(ESR1)binding with estradiol(PDB ID:1A52).The binding details were analyzed by ***:Inokosterone,ecdysterone,and cyaterone were the 3 active ingredients from Cyathula Officinalis that bind to target *** all the significantly changed genes from RA patients,ESR1,ADORA1,and ANXA1 were significantly increased in mRNA samples of RA ***:ESR1,the transcription factor that binds inokosterone in the molecular binding analysis,is the target protein of Cyathula Officinalis.

关键词： rheumatoid arthritis estrogen receptor 1 inokosterone Cyathula Officinalis Chinese medicine

THE CURVED BAR SUBJECTED TO AN ARBITRARILy DISTRIBUTED LOADIng:ANOTHER PARADOX IN THE TWO-DIMENSIONAL THEORy OF ELASTICITy

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 1996年第3期9卷 253-262页

作者： Ding, HJ Peng, NL li, y ZHEJIAng UNIV DEPT CIVIL ENGNHANGZHOU 310027PEOPLES R CHINA NANCHAng UNIV INST ENGN MECHNANCHANG 330029PEOPLES R CHINA BOSTON UNIV BOSTONMA 02215

The problem of the curved bar subjected to an arbitrarily distributed loading on the surfaces r=a and r=b is sp!ved by using the method of complex functions and expanding the boundary conditions at r=a and r=b into Fourier series. Then another paradox in the two-dimensional theory of elasticity is discovered, i. e., the classical solution becomes infinite when the curved bat is subjected to a uniform loading or when the angle included between the two ends of the curved bar 2 alpha is equal to 2 pi and the curved bar is subjected to a sine or cosine loading. In this paper the paradox is resolved successfully and the solutions for the paradox ate obtained. Moreover, the modified classical solution which remains bounded as 2 alpha approaches 2 pi is provided.

关键词： curved bar paradox elasticity

STUDy ON VERTICAL WATER TEMPERATURE MODEL FOR MIyUN RESERVOIR

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2000年第4期12卷 75-83页

作者： li, y.L. Chen, y.C. Zhang, B.X. Dep. of Hydraulic Eng. Tsinghua Univ. Beijing 100084 China

According to the characters of the Miyun reservoir located in northeast Beijing, one-dimensional method is used to establish a mathematical model of temperature for the reservoir. In this model the heat exchange between water surface and atmosphere, effective diffusion, inflows, outflows, and thermal advection are considered comprehensively. The effective diffusion coefficient, decay coefficient of short wave in water, etc, are calibrated based on the observed stratification data of 1991 in the reservoir. The mathematical model is verified through the agreement with the data of 1992. This model can be used to predict the temperature distribution along the vertical direction for the Miyun reservoir and other similar reservoir.

关键词： Computer simulation Heat transfer Mathematical models Temperature distribution

A THEORy OF EFFECTIVE THERMAL CONDUCTIVITy FOR MATRIX-INCLUSION-MICROCRACK THREE-PHASE HETEROGENEOUS MATERIALS BASED ON MICROMECHANICS

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2000年第2期13卷 179-187页

作者： Zhang, QJ Zhai, PC li, y Wuhan Univ Technol State Key Lab Adv Technol Mat Synth & Proc Wuhan 430070 Peoples R China

The effective thermal conductivity of matrix-inclusion-microcrack three-phase heterogeneous materials is investigated with a self-consistent micromechanical method (SCM) and a random microstructure finite element method(RMFEM). In the SCM, microcracks are assumed to be randomly distributed and penny-shaped and inclusions to be spherical, the crack effect is accounted for by introducing a crack density parameter, the effective thermal conductivity is derived which relates the macroscopic behavior to the crack density parameter. In the RMFEM, the highly irregular microstructure of the heterogeneous media is accurately described, the interaction among the matrix-inclusion-microcracks is exactly treated, the inclusion shape effect and crack size effect are considered. A Ni/ZrO2 particulate composite material containing randomly distributed, penny-shaped cracks is examined as an example. The main results obtained are: (1) the effective thermal conductivity is sensitive to the crack density and exhibits essentially a linear relationship with the density parameter: (2) the inclusion shape has a significant effect on the effective thermal conductivity and a polygon-shaped inclusion is more effective in increasing or decreasing the effective thermal conductivity than a sphere-shaped one; and (3) the SCM and RMFEM are compared and the two methods give the same effective property in the case in which the matrix thermal conductivity A, is greater than the inclusion one lambda(2). In the inverse case of lambda(1) y are low and differ as they are high. A reasonable explanation for the agreement and deviation between the two methods in the case of lambda(1) < lambda(2) is made.

关键词： effective thermal conductivity heterogeneous materials microcracks micromechanics