检索结果-南通市图书馆

The generalized solution of ill-posed boundary problem

在线全文

学校读者我要写书评

暂无评论

science china Mathematics 2006年第7期49卷 902-911页

作者： CAO Weiping & MA Jipu Department of Mathematics and Physics, Huaihai Institute of technology, Lianyungang 222005, china Y. Y. Tseng Functional Analysis Research Centre, harbin Normal university, harbin 150080, china Department of Mathematics and Physics Huaihai Institute of Technology Lianyungang China Y. Y. Tseng Functional Analysis Research Centre Harbin Normal University Harbin China

In this paper, we define a kind of new Sobolev spaces, the relative Sobolev spaces Wk,p0(Ω,∑). Then an elliptic partial differential equation of the second order with an ill-posed boundary is discussed. By utilizing the ideal of the generalized inverse of an operator, we introduce the generalized solution of the ill-posed boundary problem. Eventually, the connection between the generalized inverse and the generalized solution is studied. In this way, the non-instability of the minimal normal least square solution of the ill-posed boundary problem is avoided.

关键词： generalized inverse of operator, generalized solution, ill-posed boundary problem, elliptic partial differential equations of second order.

Microstructure and Tensile Properties of Yttria Coated-Alumina Particulates Reinforced Aluminum Matrix Composites

在线全文

学校读者我要写书评

暂无评论

Journal of Materials science & technology 2005年第1期21卷 68-70页

作者： Zhiqiang YU, Gaohui WU, Longtao JIANG and Dongli SUNSchool of Materials science and Engineering, harbin Institute of technology, harbin 150001, chinaPresent address: Department of Materials science, Fudan university, Shanghai 200433, chinaPh.D., to Sch. of Mat. Sci. and Eng. Harbin Inst. of Technol. Harbin 150001 China

The liquid-phase coating method was used to deposit Y2O3 ceramic on the surface of α-Al2O3. The coated-Al2O3p/6061AI composites were produced using squeeze casting technology. The microstructure and tensile properties of the composites were analysed and studied. The results showed that the coated AI2O3 particles are able to disperse homogeneously in the aluminum liquid. The microstructure of the composites is more even in comparison with that of as-received powders. The tensile testing indicated that mechanical properties of the coated-AI2O3p/6061AI composites are better than those of uncoated particles. In the composite with 30% volume fraction, the tensile strength, yield strength as well as elongation is increased by 29.8%, 38.4% and 10.3%, respectively. The SEM analysis of fracture indicated that the dimples of the coated-Al2O3p/6061Al composites are more even.

关键词： Submicron alumina powders Rare-earth oxide coating Microstructure Mechanical properties Aluminum matrix composite

Effect of rare earths on phase transformation in as-cast ZA27 alloy dur-ing compressive creep

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2003年第4期22卷 259-264页

作者： WEIXiaowei SHENBaoluo DepamnentofappliedPhysics UniversityofElectronicScienceandTechnologyofChinaChengdu610045China DeparlanentofMetalscience SichuanUniversityChengdu610065China

The effect of the mixed rare earths of Ce on the phase transformation in ascast ZA 27 alloy during compressive was investigated under 37 MPa and at 160 deg C by X-raydiffraction technique and SEM. The results showed that the as cast microstructure of ZA 27-RE alloyconsisted of a dendritic Al-rich alpha' surrounded by Zn-rich beta' phase, interdendritic epsilonphase and Zn-rich eta phase together with a complex Z phase which was a complex constitute compound,(RE,Cu)Al_5Zn_(16), dispersed in crystal interfaces or branch crystal interfaces and stable duringcompressive creep test at 160 deg C. The phase transformations of ZA 27-RE alloy, decomposition ofbeta' phase arid four transformation, were delayed by the addition of rare earths, also the lamellarstructure and the spheroidized structure in ZA 27-RE alloy were finer than in ZA 27 alloy duringcompressive creep test at 160 deg C at the same creep time, and the compressive creep resistance ofZA 27-RE alloy was higher than that of ZA 27 alloy.

关键词： microstructure change compressive creep rare earths ZA 27 alloy

DYNAMIC STRESS CONCENTRATIONS IN AMBARTSUMIAN'S PLATE WITH A CUTOUT

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 1998年第4期11卷 341-350页

作者： Hu Chao Zhao Xinghua (Institute of applied Mathematics and Mechanics,Shanghai university,Shanghai 200072,china)Ma Xingrui Huang Wenhu (harbin Institute of technology,harbin 150001,china) Inst. of Appl. Math. and Mechanics Shanghai University Shanghai 200072 China harbin Institute of technology Harbin 150001 China

Based on the motion equations of flexural wave in Ambartsumian' s plates including the effects of transverse shear deformations,by using perturbation method of small parameter,the scatter- ing of flexural waves and dynamic stress concentrations in the plate with a cutout have been studied. The asypmtotic solution of the dynamic stress problem is *** results for the dynamic stress concentration factor in Ambartsumian's plates with a circular cutout are graphically presented and discussed.

关键词： Ambartsumian's plate cutout dynamic stress concentration perturbation method

EFFECT OF BIAS STRESS ON NON-LINEAR INTERNAL FRICTION OF Al-Mg ALLOY

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 1992年第3期5卷 166-171页

作者： TAN Qi university of science and technology of china,Hefei,china Univ of science and technology of China Hefei China

The influence of longitudinal and torsional bias stresses on anomalous amplitude-dependent internal friction was *** longitudinal bias stress may always weaken the anomalous amplitude-dependent effect,while the torsional one may induce different effects from differ- ent directions *** stress effect exhibits only in properly heat treated and cold worked ahoy *** anomalous amplitude-dependent internal friction peaks,P_3,P_2 and P_1, are found to be related closely to slant dislocation kink ***,the application of bias stress to internal friction would be contributed to the study on dislocation structure.

关键词： internal friction bias stress anomalous amplitude effect dislocation kink

OSTWALD COARSENING UNDER CHANGING VOLUME FRACTION CONDITION

在线全文

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 1995年第1期5卷 67-70页

作者： Zhao Jiuzhou Guo, Jingjie Jia Jun Li Qingchun(college of Materials science and Engineering,harbin institute of technology, harbin 15000l) harbin INST TECHNOL COLL MAT SCI & ENGNHARBIN 150001PEOPLES R CHINA

ＯＳＴＷＡＬＤＣＯＡＲＳＥＮＩＮＧＵＮＤＥＲＣＨＡＮＧＩＮＧＶＯＬＵＭＥＦＲＡＣＴＩＯＮＣＯＮＤＩＴＩＯＮＺｈａｏ；ＪｉｕｚｈｏｕＧｕｏ，ＪｉｎｇｊｉｅＪｉａ；ＪｕｎＬｉ；Ｑｉｎｇｃｈｕｎ（ＣｏｌｌｅｇｅｏｆＭａｔｅ... 详细信息

ＯＳＴＷＡＬＤＣＯＡＲＳＥＮＩＮＧＵＮＤＥＲＣＨＡＮＧＩＮＧＶＯＬＵＭＥＦＲＡＣＴＩＯＮＣＯＮＤＩＴＩＯＮＺｈａｏ；ＪｉｕｚｈｏｕＧｕｏ，ＪｉｎｇｊｉｅＪｉａ；ＪｕｎＬｉ；Ｑｉｎｇｃｈｕｎ（ＣｏｌｌｅｇｅｏｆＭａｔｅｒｉａｌｓＳｃｉｅｎｃｅａｎｄＥｎ...

关键词： Ostwald coarsening second phase volume fraction

Effects of binders on the performance of electric double-layer capacitors of carbon nanotube electrodes

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 453-457页

作者： LI Chensha1*, WANG Dazhi1, ZHANG Baoyou2, WANG Xiaofeng1, CAO Maosheng3 and LIANG Ji1(1. Department of Mechanical Engineering, Tsinghua university, Beijing 100084, china 2. Center for Analysis and Measurement, harbin Institute of technology, harbin 150001, china 3. School of Material science and Engineering, Tsinghua university, Beijing 100084, china) Department of Mechanical Engineering Tsinghua University Beijing 100084 China Center for Analysis and Measurement Harbin Institute of Technology Harbin 150001 China School of Material science and Engineering Tsinghua University Beijing 100084 China

Polarizable electrodes of electric double layer capacitor (EDLCs) were made from carbon nanotubes. Effects of different binders, which are phenolic resin (PF) and polytetrafluoroethylene (PTFE), on the properties of polarizable electrodes are studied. Results indicate that the microstructure, pore size distribution and specific capacitance of the electrodes with PTFE binder are superior to those electrodes with PF binder after carbonization. The suitable binder (PTFE) for carbon nanotubes electrodes is proposed.

关键词： carbon nanotubes electric double-layer capacitors phenolic resin polytetrafluoroethylene.

The Process of TiB_2-Cu Composite Phase and Structure Formation during Combustion Synthesis

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 science) 2006年第4期21卷 113-116页

作者：徐强 School of Materials science and Engineering Beijing Insitute of TechnologyBeijing 100081China

The reaction process of combustion synthesis for TiB2 -Cu was investigated in detail using combustion-wave arresting experiment, X-ray diffraction （ XRD ） analysis, SEM analysis and differential thermal analysis （ DTA ）. The XRD analysis results for the different parts of the quenched specimen show that TiCux intermetallic phase firstly forms with the propagation of combustion wave, and then Ti1.87 B50 and Ti3B4 metastable phases come forth due to the diffusion of B atoms and finally the stable TiB2 phase forms because of the continuous diffusion of B atoms. The formation of TiB2 phase is uot completed by one step, but undergoes several transient processes. The process of reaction synthesis for Ti-B-Cu ternary system can be divided into three main stages： melting of Cu and Ti , and the formation of Cu- Ti melt and few TiCux , TiBx intermetallic phases ; large numbers of TiCux intermetallic phases formation and some fine TiB2 particles precipitation ; and the TiB2 particles coarsening and the stable TiB2 and Cu two phases formation in the final product.

关键词： combustion synthesis reaction process TiB2 phase combustion-wave arresting experiment

Investigation of 'chazi'(damaged-enamels)on Chenghua doucai Porcelains

在线全文

学校读者我要写书评

暂无评论

science china(Technological sciences) 2009年第6期52卷 1722-1729页

作者： DU Feng1 & SU BaoRu2 1 Institute of Chemistry & Molecular Engineering,Qingdao university of science & technology,Qingdao,china 2 college of Information science & technology,Qingdao university of science & technology,Qingdao,china Institute of Chemistry & Molecular Engineering Qingdao University of Science & Technology college of Information science & technology

At the end of the 1950s,Sun Yingzhou considered that the 'chazi'(damaged colour)on Chenghua doucai imperial porcelain as a defect was originally produced in firing process during Chenghua period(1465―1487).Researchers in china have accepted his *** any fragment with the 'chazi' has never been found in several tons of Chenghua imperial sherds excavated from Ming imperial kiln site in *** china,few scholars have questioned the formation of 'chazi',and further investigated *** researchers at the Research Laboratory in the British Museum,employing unde-structive EDXRF,have analyzed the chemical composition of the 'chazi'(damaged colour)on a Chen-ghua doucai stem cup in the museum,and they have confirmed that the 'chazi'(damaged colour)was caused by the fire of the Jianfu palace in the Forbidden City in *** on their research,the authors studied the colour chemical principle of the 'chazi's' formation *** to the ceramic technology principle,scientific reasoning for the 'chazi' was carried *** the help of the history of Qing court,the brainteaser of the 'chazi' was totally uncovered,the misunderstanding for the 'chazi' has also been *** research also suggests that employing modern science and technology is a direction to study Chinese ancient ceramic further.

关键词： Chenghua doucai porcelains court eunuchs the set on fire at the Jianfu palace ’chazi’(damaged-enamels) the British Museum colour chemical principle archaeology using science and technology