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Improving the Input of Classified Neural Networks Through Feature Construction

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Journal of Systems Engineering and Electronics 2001年第3期12卷 85-89页

作者： Yang, L. yu, z. Huang, L. School of Economics and Management Tongji University Shanghai 200092 China

A general classification algorithm of neural networks is unable to obtain satisfied results because of the uncertain problems existing among the features in moot classification programs, such as interaction. With new features constructed by optimizing decision trees of examples, the input of neural networks is improved and an optimized classification algorithm based on neural networks is presented. A concept of dispersion of a classification program is also introduced too in this paper. At the end of the paper, an analysis is made with an example.

关键词： Feature construction Neural networks Dispersion Decision trees Hyperplane.

Preparation and Microstructure Analysis of High Strength Cementitious Materials Containing Metakaolin

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武汉理工大学学报 2010年第17期32卷 117-122,136页

作者： yu R SHUI z H DONG J School of Materials Science and Engineering Wuhan University of TechnologyWuhan 430070China

The preparation and microstructure analysis of high strength cementitious materials containing metakaolin (MK) was studied in this paper. The MK was prepared firstly,and then was mixed with fly ash,ground blast furnace slag,quartz powder and cement with different percentage to produce high strength cementitious materials. After cured under different environment,the compressive strength of such materials was tested. Techniques of X-ray diffraction (XRD) and scanning electron microscopy (SEM) were further employed to identify the composition and microstructure. The results obtained reveal that the compressive strength of such materials mainly effected by component of raw materials,the water binder ratio (W/B) and the curing regime. When the three factors above are optimized,the compressive strength of such materials can get to 156 MPa in maximum. The X-ray diffraction analysis and the scanning electron microscopic images indicated that under optimal curing condition,more raw materials can take chemical reaction and the microstructure is dense to yield good mechanical properties.

关键词： preparation microstructure analysis high strength cementitious materials metakaolin

A Review of the Effects of Fly Ash on Durability of Concrete：Hydration Chemistry and Microstructure

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武汉理工大学学报 2010年第17期32卷 235-240页

作者： yu z Q YE G VAN BREUGEL K Faculty of Civil Engineering and Geosciences Delft University of TechnologyP.O. Box 50482600 GA DelftThe Netherlands

Fly ash (FA) is widely used in construction industry as a pozzolanic material for its economic and environmental advantages. However,the variety and the complexity of the chemical composition of FA make it difficult to control the quality in engineering practice. Especially the durability of FA concrete has to be considered in the design. This durability is strongly influenced by the internal chemistry and the microstructure of cement paste. The aim of this article is to present a review on the effect of FA on the durability of concrete with particularly focus on the hydration chemistry and the development of microstructure. Meanwhile,existing hydration models for hydration kinetics and microstructure development of concrete blended with FA is discussed. The results of this research will provide a modelling perspective for predicting durability of concrete when FA is used as a blending material in the mixtures.

关键词： durability fly ash hydration chemistry microstructure modelling

Identification of Orientia tsutsugamushi,spotted fever group and typhus group Rickettsia by duplex and nested PCR methods

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Asian Pacific Journal of Tropical Medicine 2008年第4期1卷 1-8页

作者： M-C Luan D-z yu L Tang L-J zhang Department of Rickettsiology National Institute of Communicable Disease Control and PreventionChina CDC Department of Microorganism Dalian Center for Disease Control and Prevention Department of Microecology Dalian medical university Department of Rickettsiology National Institute of Communicable Disease Control and PreventionChina.CDC

Objective:To identify members of genera of rickettsia and *** ***:Rapid and duplex and nested PCR methods have been established by designing primers based on the conserved regions of heat shock protein GroEL gene.345 mouse viscera samples including liver,spleen and kidney,96 Xenopsylla cheopis and 32 chiggers collected from Hongta areas of yuxi city,yunnan province were tested by the new PCR ***:The result of the study showed that the new PCR methods could identify most members of genera -Rickettsia and Orientia simultaneously with 100%specificity and its sensitivity could test one copy per *** results of detection prevalence of rickettsioses in mouse,flea and mites DNA samples showed that the total rickettsia infection rate in mouse was 34.78%(120/345).The total infection rates in ***,O.t Karp and *** of mouse samples were 28.12%(97/345),19.71%(68/345) and O. 29%(1/345) ***-infection rates in *** and 0.t Karp of mouse samples were 13.33%(46/ 345).O.t Karp type has been the main epidemic strain in these ***:We concluded that this PCR method could be used to detect multi-genera rickettsia *** evidences provided in this and previous studies strongly support that Hongta areas of yuxi city are a natural focus for typhus and scrub typhus with the common occurrence of their confection.

关键词： Rickettsia,GroEL gene Duplex and nested PCR

HEAT TREATMENT STRENGTHENING EFFECTS OF RARE EARTHS ON Mg-9Al ALLOY

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Acta Metallurgica Sinica(English Letters) 2003年第1期16卷 8-14页

作者： Y.S.Wang J.z.yu Q.D.Wang W.J.Ding Shanghai Cosmopolitan Automobile Accessory Co. LTD Shanghai 200083 China School of Materials Science and Engineering Shanghai Jiao Tong University Shanghai 200030 China

Mg-9Al-xRE magnesium alloys were studied, where, x is 0, 0.4. 0.8. 1.2 and 1.6% (in weight percent, wt%), respectively. Influence of rare earths (RE) on micro structure. and strength in both T4 (solute heat treatment) and T6 (solute heat treatment and artificial ageing treatment) were investigated. Strength of specimen was tested at ambient temperature. The micro structure was analyzed by optical microscopy, scanning electron microscopy (SEM) and X-ray diffraction analysis. RE additions improved T4 tensile strength of the treated alloys. Small addition (0.4wt%) of RE greatly improved the strength of ageing treated (T6) Mg-9Al alloy, but further additions caused decreasing.

关键词： Mg-Al alloy rare earth (RE) heat treatment mechanical property strength

Adaptive Finite Element Modeling Techniques for the Poisson-Boltzmann Equation

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Communications in Computational Physics 2012年第1期11卷 179-214页

作者： M.Holst J.A.McCammon z.yu Y.C.zhou Y.zhu Department of Mathematics University of California at San DiegoLa JollaCA 92093USA Department of Physics University of California at San DiegoLa JollaCA 92093USA Department of Chemistry&Biochemistry University of California at San DiegoLa JollaCA 92093USA Center for Theoretical Biological Physics(CTBP) University of California at San DiegoLa JollaCA 92093USA National Biomedical Computation Resource(NBCR) University of California at San DiegoLa JollaCA 92093USA Howard Hughes Medical Institute University of California at San DiegoLa JollaCA 92093USA

We consider the design of an effective and reliable adaptive finite element method(AFEM)for the nonlinear Poisson-Boltzmann equation(PBE).We first examine the two-term regularization technique for the continuous problem recently proposed by Chen,Holst and Xu based on the removal of the singular electrostatic potential inside biomolecules;this technique made possible the development of the first complete solution and approximation theory for the Poisson-Boltzmann equation,the first provably convergent discretization and also allowed for the development of a provably convergent ***,in practical implementation,this two-term regularization exhibits numerical ***,we examine a variation of this regularization technique which can be shown to be less susceptible to such *** establish a priori estimates and other basic results for the continuous regularized problem,as well as for Galerkin finite element *** show that the new approach produces regularized continuous and discrete problemswith the samemathematical advantages of the original *** then design an AFEM scheme for the new regularized problem and show that the resulting AFEM scheme is accurate and reliable,by proving a contraction result for the *** result,which is one of the first results of this type for nonlinear elliptic problems,is based on using continuous and discrete a priori L¥*** provide a high-quality geometric model as input to the AFEM algorithm,we also describe a class of feature-preserving adaptive mesh generation algorithms designed specifically for constructing meshes of biomolecular structures,based on the intrinsic local structure tensor of the molecular *** of the algorithms described in the article are implemented in the Finite Element Toolkit(FETK),developed and maintained at *** stability advantages of the new regularization scheme are demonstrated with FETK through comparisons with the original regula

关键词： Poisson-Boltzmann equation semi-linear partial differential equations supercritical nonlinearity singularity a priori L¥estimates existence uniqueness well-posedness Galerkin methods discrete a priori L¥estimates quasi-optimal a priori error estimates adaptive finite methods contraction convergence optimality surface and volume mesh generation mesh improvement and decimation.

Anomalous temperature effect of nonlinearity of WO_3 varistor doped with Al_2O_3

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Chinese Science Bulletin 1999年第7期44卷 671-672页

作者： WANG yu, z. Aburas and YAO KailunDepartment of Physics , Huazhong University of Science and Technology, Wuhan 430074, China Department of Physics Huazhong University of Science and Technology Wuhan China

MAKAROV and Trontelj first reported the WO3-based low voltage varistor material doped with MnO2 and Na2CO3 in 1994. This material is worth further study because of its low threshold voltage （ 2O3 can obviously improve the nonlinearity of WO3-MnO2-Na2CO3 series with nonlinear coefficient α≈ 2,and a may be higher than 5 when the amount of Co2O3 is 1% （mole percentage）. However, the nonlinear characteristic almost vanished when 0.5% Al2O3 was doped into this system at room temperature, and Al2O3 showed very stable

关键词： Anomalous temperature effect of nonlinearity of WO3 varistor doped with Al2O3 Al

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前后多车影响的跟驰模型及稳定性分析

交通运输系统工程与信息 2018年第6期18卷 41-47,80页

作者：彭勇刘世洁 DENNIS z yu 重庆交通大学交通运输学院重庆400074 克拉克森大学商学院

驾驶员在跟车行驶过程中,通常会通过视野前后车辆的行驶状态来调整自己的跟驰行为,基于此本文提出了一种考虑驾驶员视野内双前车和后车对跟驰车辆影响的改进跟驰模型.根据线性稳定分析方法,得到了改进模型的中性稳定性条件,并通过计算... 详细信息

驾驶员在跟车行驶过程中,通常会通过视野前后车辆的行驶状态来调整自己的跟驰行为,基于此本文提出了一种考虑驾驶员视野内双前车和后车对跟驰车辆影响的改进跟驰模型.根据线性稳定分析方法,得到了改进模型的中性稳定性条件,并通过计算机仿真模拟进行了验证.为了进一步加强验证结果及说明改进模型的优越性,同经典FVD模型进行了数值仿真对比.仿真结果表明:灵敏度α越大越有利于提高改进跟驰系统的稳定性;同经典FVD跟驰模型相比,改进模型抵抗干扰的能力更突出,能够消散交通系统中的微小扰动,具有抑制交通拥堵和稳定交通流的有利作用.

关键词：综合交通运输跟驰模型稳定性分析前后多车交通系统仿真

Effects of chemical pressure on diluted magneticsemiconductor(Ba,K)(zn,Mn)_2As_2

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Chinese Physics B 2019年第5期28卷 288-292页

作者： Y Peng S yu G Q zhao W M Li J F zhao L P Cao X C Wang Q Q Liu S J zhang R z yu z Deng X H zhu C Q Jin College of Materials Science & Engineering Sichuan University Beijing National Laboratory for Condensed Matter Physics and Institute of Physics Chinese Academy of Sciences School of Physics University of Chinese Academy of Sciences Collaborative Innovation Center of Quantum Matter

Chemical pressure induced by iso-valent doping has been widely employed to tune physical properties of materials. In this work, we report effects of chemical pressure by substitution of Sb or P into As on a recently discovered diluted magnetic semiconductor(Ba,K)(zn,Mn)_2 As_2, which has the record of reliable Curie temperature of 230 K due to independent charge and spin doping. Sb and P are substituted into As-site to produce negative and positive chemical pressures, respectively.X-ray diffraction results demonstrate the successful chemical solution of dopants. Magnetic properties of both K-underdoped and K-optimal-doped samples are effectively tuned by Sb-and P-doping. The Hall effect measurements do not show decrease in carrier concentrations upon Sb-and P-doping. Impressively, magnetoresistance is significantly improved from7% to 27% by only 10% P-doping, successfully extending potential application of(Ba,K)(zn,Mn)_2 As_2.

关键词： chemical pressure (Ba,K)(zn,Mn)2As2 diluted magnetic semiconductor iso-valent doping