检索结果-南通市图书馆

science china(Technological sciences) 2005年第5期48卷 510-520页

作者： SU Juanhua1,2. LIU Ping2. DONG Qiming2.& LI Hejun1 1. college of materials {2. and Engineering, Northwestern Polytechnical university, Xi’an 710072. china 2. college of materials science and Engineering, Henan university of {2. and Technology, Luoyang 471003, china college of materials {2. and Engineering Northwestern Polytechnical University Xi’an China college of materials {2. and Engineering Henan University of Science and Technology Luoyang China

The thermomechanical treatment process is effective in enhancing the properties of the lead frame copper alloy. In this study, an optimal pattern of the thermomechanical processes for Cu-Cr-Zr was investegated using an intelligent control technique consisting of neural networks and genetic algorithms. The input parameters of the artificial neural network (ANN) are the reduction ratio of cold rolling, aging temperature and aging time. The outputs of the ANN model are the two most important properties of hardness and conductivity. Based on the successfully trained ANN model, genetic algorithms (GA) are used to optimize the input parameters of the model and select perfect combinations of thermomechanical processing parameters and properties. The good generalization performance and optimized results of the integrated model are achieved.

关键词： Cu-Cr-Zr alloy, thermomechanical processing optimization, artificial neural network, genetic algorithms.

A new ordered phase forming during ageing in Cu-Ti alloys

在线全文

学校读者我要写书评

暂无评论

Chinese science Bulletin 1997年第19期42卷 1671-1672页

作者： WEI Yinghui and WANG Xiaotian1. Department of materials science, Taiyuan {2. of Technology, Taiyuan 03002., china 2. college of materials science, Xi’an jiaotong {2., Xi’an 710049, china Ion Beam Laboratory Shanghai Institute of Metallurgy Chinese Academy of Sciences Shanghai 200050 China

AGE-hardened Cu-Ti has been an important alloy of investigation in the field of continuousphase transformation due to its complicated transformation processes which involve short rangeordering (SRO), spinodal decomposition (SD), long range ordering (LRO), etc. So far, ithas been a controversial topic whether each process exists, and in what sequence they pro-ceed.

关键词： Ti Cu A new ordered phase forming during ageing in Cu-Ti alloys

Magnetron sputtering synthesis of large area well-ordered boron nanowire arrays

在线全文

学校读者我要写书评

暂无评论

science china(Physics,Mechanics & Astronomy) 2004年第4期47卷 403-415页

作者： CAO Limin1,2. ZHANG Ze2.& WANG Wenkui1,2.1. Key Laboratory of Metastable materials science and Technology and {2. of materials science and Engineering, Yanshan university, Qinhuangdao 066004, china 2. Institute of Physics, Chinese Academy of sciences, Beijing 100080, china Key Laboratory of Metastable materials science and Technology and {2. of materials science and Engineering Yanshan University Qinhuangdao China Institute of Physics Chinese Academy of Sciences Beijing China

One-dimensionally nanostructured materials, such as nanowires and nanotubes, are the smallest dimensional structures for efficient transport of electrons and excitons, and are therefore critical building blocks for nanoscale electronic and mechanical devices. In this paper, boron nanowires with uniform diameters from 2. to 80 nm were synthesized by radio-frequency magnetron sputtering of pure boron powder and B2.3 powder mixtures in argon atmosphere. The boron nanowires produced stand vertically on the substrate surface to form well-ordered arrays over large areas with self- organized arrangements without involvement of any template and patterned catalyst. The high-density boron nanowires are parallel to each other and well distributed, forming highly ordered and uniform arrays. A more interesting and unique feature of the boron nanowires is that most of their tips are flat rather than hemispherical in morphologies. Detailed studies on its structure and composition indicate that boron nanowires are amorphous. Boron nanowire appears as a new member in the family of one-dimensional nanostructures. Considering the unique properties of boron-rich solids and other nanostructures, it is reasonable to expect that the boron nanowires will display some exceptional and interesting properties. A vapor-cluster-solid (VCS) mechanism was proposed to explain the growth of boron nanowires based on our experimental observations.

关键词： boron nanowires, magnetron sputtering, arrays, self-assembly.

A novel algorithm of artificial immune system for high-dimensional function numerical optimization

在线全文

学校读者我要写书评

暂无评论

Progress in Natural science:materials International 2005年第5期15卷 463-471页

作者： DU Haifeng 1,2.*, GONG Maoguo1, JIAO Licheng1 and LIU Ruochen1(1. Institute of Intelligent Information Processing and Key Laboratory of Radar Signal Processing, Xidian university, Xi'an 710071, china 2. School of Mechanical Engineering, Xi'an {2. university, Xi'an 710049, china) Institute of Intelligent Information Processing and Key Laboratory of Radar Signal Processing Xidian University Xi''an 710071 China School of Mechanical Engineering Xi''an Jiaotong University Xi''an 710049 China

Based on the clonal selection theory and immune memory theory, a novel artificial immune system algorithm, immune memory clonal programming algorithm (IMCPA), is put forward. Using the theorem of Markov chain, it is proved that IMCPA is convergent. Compared with some other evolutionary programming algorithms (like Breeder genetic algorithm), IMCPA is shown to be an evolutionary strategy capable of solving complex machine learning tasks, like high-dimensional function optimization, which maintains the diversity of the population and avoids prematurity to some extent, and has a higher convergence speed.

关键词： clonal selection immune memory artificial immune system evolutionary algorithms Markov chain.

Fuzzy controllers based on some fuzzy implication operators and their response functions

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural science:materials International 2004年第1期14卷 16-21页

作者： LI Hongxing 1*, YOU Fei 1 and PENG Jiayin 2.1. Department of Mathematics, Beijing Normal university, Beijing 100875, china 2. Department of Mathematics, Neijiang Teacher's {2., Neijiang 641112. china) Department of Mathematics Beijing Normal University Beijing 100875 China. Department of Mathematics Neijiang Teacher''s College Neijiang 641112 China

The fuzzy controllers constructed by 2. fuzzy implication operators based on CRI algorithm and their response functions are discussed. The conclusions show that the fuzzy controllers constructed by 9 fuzzy implication operators are universal approximators to continuous functions and can be used in practical fuzzy control systems. And these 9 fuzzy implication operators except for Einstein operator intersection are all the adjoint pairs of some fuzzy implication operators. Besides, there are 3 other fuzzy controllers formed by fuzzy implication operators being regarded approximately as fitted functions.

关键词： fuzzy implication operators CRI algorithm fuzzy controllers response functions universal approximators

Synthesis of New Polyether Polycarboxylate Superplasticizer

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Wuhan university of Technology(materials {2.) 2010年第5期25卷 799-802页

作者：麻秀星 materials college Chongqing University Xiamen Academy of Building Research Group

The effects of various factors on the synthesis process and the performances of product, including batch feeding way and the dosage of the radical initiator, the system concentration, the reaction temperature and the reaction time were discussed. A kind of polycarboxylate superplasticizer with allyl alcohol polyethylene glycol, maleic anhydride and methacrylic acid sulfonic sodium as main raw materials has been synthesized. Their relative effectiveness as dispersants was evaluated in cement paste by measuring paste fluidity. The optimum parameters of technology and the appropriate proportion of raw materials were obtained. As a result,the new high performance superplasticizer suitable for high-performance concrete has been synthesized. The structure of copolymer was characterized and analyzed by FT-IR spectra. Results indicated that product copolymer structure was consistent with the ideal molecular structure designed.

关键词： polycarboxylate maleic anhydride high-performance superplasticizer free radical polymerization

Surface Nanocrystallization of Magnesium Alloy AZ91D by High-Energy Shot Peening

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan university of Technology(materials {2.) 2009年第4期24卷 515-519页

作者：张津 School of materials science & Engineering University of Science and Technology Beijing college of materials {2. & Engineering Chongqing University of Technology

High-energy shot peening （HESP）, a method to produce severe plastic deformation by high velocity flying balls, was applied on die cast magnesium alloy AZ91D. Effects of surface nanocrystallization by HESP and heat treatment at different temperatures were investigated. The mi- crostructure evolution was conducted using X-ray diffraction （XRD） and field emission scanning electronic microscopy （FESEM）. The hardness was measured by microhardness tester. The experimental results show that surface nanocrystrallization of AZ91D obtained by HESP would lead to the increase of microhardness. Low temperature heated at 100℃ for 1 h do not change the property obviously. However, both the microstructure and microhardness vary greatly after heat treatment at 400℃ for 1 h.

关键词： AZ91 D surface nanocrystallization HESP microhardnss corrosion resistance

Crystal structures and electronic properties of BaC_2.isomers by theoretical study based on DFT

在线全文

学校读者我要写书评

暂无评论

science china Chemistry 2008年第6期51卷 545-550页

作者： FENG Jing1,XIAO Bing2.& CHEN JingChao1 1 Key Laboratory of Advanced materials of Precious-Nonferrous Metals,Education Ministry of china,and Key Lab of Advanced materials of Yunnan Province,Kunming university of science and Technology,Kunming 650093,china 2.School of materials science and Engineering,Xi’an jiaotong university,Xi’an 710049,china Key Laboratory of Advanced materials of Precious-Nonferrous Metals Education Ministry of China and Key Lab of Advanced Materials of Yunnan Province Kunming University of Science and Technology Kunming 650093 China School of materials science and Engineering Xi'an Jiaotong University Xi'an 710049 China

Band structures and electronic properties of two BaC2.isomers were calculated by using density func-tional theory(DFT) *** ionic bond features are all typical between cation(Ba) and anion clusters(C2. in both structures of the ***,a much stronger covalent bond exists in anion clusters which can be seen by inspecting the electron distribution contour that has a dull bell like shape between two carbon *** shortest distance between Ba2. and C2.? and the bond length in anion clusters are different in these isomers of BaC2.which are 0.2.45 nm and 0.1185 nm for the structure with the I4/mmm space group and 0.2.44 and 0.1136 nm with the C2.c type,*** structures were clarified by combining the DOS to indicate the ionic bonding features more *** analysis provided further evidence on these *** calculation results reveal that the transition temperature of these two polymorphs of BaC2.locates near 132.K,which is consistent with the recent experimental results.

关键词： functional materials metal diaries phase transition electron density first principle calculation orbital bonding state

Effect of Annealing Ambience on the Chemical Stability of Zr-Si-N Diffusion Barrier

在线全文

学校读者我要写书评

暂无评论

材料热处理学报 2004年第5B期25卷 1225-1228页

作者： SONGZhong-xiao WANGYuan XUKe-wei LIUChun-liang KeyLabforPhysicalElectronicsandDevicesMinistryofEducation Xi＇anJiaotongUniversity710049Xi＇anChina State-KeyLaboratoryforMechanicalBehaviorofmaterials Xi＇anJiaotongUniversity710049Xi＇anChina

Zr-Si-N films were deposited by RF magnetron sputtering (MS) technique. A Cu film on the top of Zr-Si-N films was prepared by DC pulsed magnetron sputtering. The Cu/Zr-Si-N systems were annealed in vacuum and N2.H2.gas mixture at 800°C, respectively. The structure of the films were characterized by X-ray diffraction (XRD), Auger electron spectroscopy (AES) and four-point probe method. The sheet resistances of the Cu/Zr-Si-N/Si contact systems annealed in N2.H2.gas mixture were lower than those of the specimens annealed in vacuum at 800°C. The residual oxygen contamination from vacuum annealing ambience influences the sheet resistances of the Cu/Zr-Si-N/Si contact systems due to residual oxygen contamination and/or voids in Cu films. Though thermal stabilities of the Cu/Zr-Si-N/Si systems were maintained up to 800°C when annealed in vacuum and N2.H2.gas mixture, the changes of thermal stability of specimens were noticeable. The vacuum can accelerate the oxidation and decomposition of Zr-Si-N barrier. On the contrary, N2.H2.gas mixture prevent from the Zr-Si-N barrier oxidation and decomposition.

关键词：扩散势垒 Zr-Si-N 退火化学稳定性

Construction of a genetic map and localization of QTLs for yield traits in tomato by SSR markers

在线全文

学校读者我要写书评

暂无评论

Progress in Natural science:materials International 2005年第9期15卷 793-797页

作者： LIU Yang 1,2., CHEN Huoying1**, WEI Yutang2.and ZHUANG Tianming1(1. Department of Plant science, Shanghai jiaotong {2., Shanghai 2.1101, china 2. Department of Horticulture, Shenyang Agricultural {2., Shenyang 110161, china) Department of Plant science Shanghai Jiaotong University Shanghai 201101 China. Department of Horticulture Shenyang Agricultural University Shenyang 110161 China

Using an F2.opulation derived from the hybrid of Lycopersicon esculentum Mill. ‘XF 98-7’× Lycopersicon pimpinellifolium LA2.84, a SSR genetic linkage map of tomato is constructed. The map contains 112.markers and spans 808.4 cM with an average distance of 7.2. cM between loci. Two quantitative trait loci （QTLs） for first flower node on chromosomes 5 and 11, two QTLs for number of flowers per truss on chromosomes 2.and 5, and five QTLs for fruit weight on chromosomes 1, 2. 3, 9 and 12.are identified.

关键词： tomato SSR markers genetic mapping first flower node number of flowers per truss fruit weight.