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Chinese Journal of Mechanical engineering 2000年第2期13卷 122-125页

作者： Jing Hongyang (college of material science and engineering, Tianjin University) Minami Fumiyoshi (Osaka University, Japan) 天津大学天津 Osaka University 日本 Osaka

The transferability of the toughness results in ductile-brittle transition region for welded cracked specimens is conducted by 3D FE analysis. The fracture toughness Values for the double edge notched tension specimens are predicted effectively from the bend test results based on the local approach considering stable crack growth. It is found that the cell model gives a good description of the stable crack growth behavior, and the local approach is useful for the transferability analysis of fracture toughness results in ductile-brittle transition region.

关键词： Flacture toughness Stable crack growth 3D FE analysis

Theoretical analysis of alloy multiplying factor by the empirical electron theory of solids and molecules

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science China(Technological sciences) 2007年第6期50卷 807-814页

作者： SONG YuePeng1,2, LIU GuoQuan2, LI ZhiLin3, FENG ChengMing1 1 Mechanical and Electronic engineering college, Shandong Agricultural University, Tai’an 271018, China 2 college of materials science and engineering, University of science and Technology, Beijing 100083, China 3 college of material science and engineering, Beijing University of Chemical Technology, Beijing 100029, China Mechanical and Electronic engineering college Shandong Agricultural University Tai’an China college of materials science and engineering University of Science and Technology Beijing China college of material science and engineering Beijing University of Chemical Technology Beijing China

By introducing the distribution probability of structural units in austenite contain- ing alloying elements and considering its effects on phase transformation, this paper establishes a calculation model of distribution probability of structural units. A new valence electron structure (VES) parameter-transformation effect coefficient of alloying elements (HL), is defined and then studied both theoretically and ex- perimentally. The relationship between the parameter HL and the multiplying factor (the quenching capability factor) of alloying elements is studied. The results indi- cate that the two parameters (HL and the quenching capability factor) have the same variation characteristic and substance feature. Therefore, the multiplying factor virtually expresses the relative quantity of structural units in the alloying elements-containing austenite.

关键词： multiplying factor (the quenching capability factor), empirical electron theory of solids and molecules, transformation effect coefficient of alloying elements, structural units in austenite containing alloying elements

Characterization of ZnO Based Varistor Derived from Nano ZnO Powders and Ultrafine Dopants

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Journal of materials science & Technology 2005年第2期21卷 183-186页

作者： Weizhong YANG, Dali ZHOU, Guangfu YIN, Runsheng WANG and Yun ZHANG college of material science and engineering, Sichuan University, Chengdu 610064, China Coll. of Mat. Sci. and Eng. Sichuan Univ. Chengdu 610064 China

Nanosized ZnO powders were prepared with a two-step precipitation method. The average size of ZnO particles was about 80 nm and their size distribution was narrow. Combining with ultrafine additive powders, ZnO base varistor was produced via an oxide mixing route. ZnO varistor derived from normal reagent grade starting materials was investigated for comparison purpose. Outstanding microstructure of the ZnO varistor derived from nanosize ZnO powders and ultrafine dopants was obtained: uniform distribution of fine ZnO grains (less than 3 microns), grain boundary and the dopant position. Higher varistor voltage (U=492 V/mm) and nonlinear coefficient (α=56.2) as well as lower leakage current (TL=1.5 μuA) were achieved. The better electrical properties were attributed to the uniform microstructure, which in turn led to stable and uniform potential barriers. Also this improved technique is more feasible for producing ZnO nanopowders and resulting varistor in large scales.

关键词： Zinc oxide (ZnO) Varistor Nanopowders Ultrafine dopants Two-step precipitation

A NOVEL INTERPRETATION OF CONCENTRATION DEPENDENCE OF VISCOSITY OF DILUTE POLYMER SOLUTION

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Chinese Journal of Polymer science 2000年第1期18卷 57-67页

作者： Yan Pan Rong-shi Cheng college of material science and engineering, South China University of Technology, Guangzhou 510641, China college of Chemistry and Chemical engineering, Nanjing University, Nanjing 210093, China 华南理工大学广东广州

The concentration dependence of the reduced viscosity of dilute polymer solution is interpreted in the light of a new concept of the self-association of polymer chains in dilute solution. The apparent self-association constant is defined as the molar association constant divided by the molar mass of individual polymer chain and is numerically interconvertible with the Huggins coefficient. The molar association constant is directly proportional to the effective hydrodynamic volume of the polymer chain in solution and is irrespective of the chain architecture. The effective hydrodynamic volume accounts for the non-spherical conformation of a short polymer chain in solution and is a product of a shape factor and hydrodynamic volume. The observed enhancement of Huggins coefficient for short chain and branched polymer is satisfactorily interpreted by the concept of self-association. The concept of self-association allows us to predict the existence of a boundary concentration C-s(dynamic contact concentration) which divides the dilute polymer solution into two regions.

关键词： self-association polymer solution viscosity concentration dependence

Analysis of variance for testing method of cement in determination of strength

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Progress in Natural science:materials International 2011年第4期21卷 341-346页

作者： Hong HUANG,Xiao-dong SHEN State Key Laboratory of materials-Oriented Chemical engineering,college of material science and engineering, Nanjing University of Technology,Nanjing 210009,China State Key Laboratory of materials-Oriented Chemical engineering College of Material Science and Engineering Nanjing University of Technology Nanjing 210009 China

The statistical tools such as descriptive statistics,full factorial design and analysis of source of variation were used to identify the potential factors that impact the validity of testing method for determining the strength of *** results showed that personal error impacted both accuracy and precision of test *** time associated with temperature fluctuation resulted in strength variation but did not impact the precision of test in all curing *** compactions did not impact the precision of test but resulted in the strength variation on 3 d and 28 d *** methods for the initial moist air curing significantly impacted the precision of testing method and resulted in the strength variation of cement on 1 d.

关键词： testing method of cement analysis of variance strength accuracy precision

PERFORMANCE AND INITIATION MECHANISM OF ISOPROPYLTHIOXANTHONE IN SURFACE PHOTOGRAFTING

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Chinese Journal of Polymer science 2000年第5期18卷 431-435页

作者： Wan-tai Yang Mei-zhen Yin Yu-feng Sun college of material science and engineering, Beijing University of Chemical Technology, Beijing 100029, China 北京化工大学北京

In a polymerization model with low density polyethylene (LDPE) as the substrate and acrylic acid (AA) as the monomer, the performance of isopropylthioxanthone (ITX) in initiating surface photografting polymerization was evaluated. The results show that the reactivity of photopolymerization and photografting of ITX locate between benzophenone (BP) and benzildimethylketal (BDK) for polymerization, BDK > ITX > BP; for surface grafting polymerization, BP > ITX > BDK. These results can be explained by a reaction mechanism of the inter-molecular or intra-molecular hydrogen abstraction reaction of ITX.

关键词： photografting polymerization photopolymerization hydrogen abstraction reaction

Study on BaTiO_3 films prepared by AC power microarc oxidation

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science China(Technological sciences) 2009年第8期52卷 2195-2199页

作者： HUANG WenBo, LI WenFang & HAN Bing college of material science and engineering, South China University of Technology, Guangzhou 510640, China college of material science and engineering South China University of Technology Guangzhou China

BaTiO3 films were prepared by microarc oxidation (MAO) with an in-house built alternating current (AC) power supply in Ba(OH)2 solution in this study. The surface morphology, combinability with the substrate and phase composition of the films were investigated by XRD, SEM and TEM. The BaTiO3 films were annealed at a temperature range of 900 to 1200℃ and phase compositions were tested thereafter. The results showed that the BaTiO3 films were mainly composed of the primitive hexagonal phase with relatively small amount of tetragonal and amorphous phases. Moreover, the amount of amorphous phase decreased with the time of annealing. The transformation of BaTiO3 from hexagonal structure to tetragonal stucture became obvious until the annealing temperature reached 1200℃. The film consisted mainly of BaTiO3 tetragonal structure with ferroelectric property. The influence of annealing on surface morphology and mechanism of phase transformation of the films were also discussed.

关键词： microarc oxidation ferroelectric film BaTiO3 annealing phase composition

Statistical study of cement additives with and without chloride on performance modification of Portland cement

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Progress in Natural science:materials International 2011年第3期21卷 246-253页

The effectiveness of cement additives with and without chloride on the fluidity and the strength development of Portland cement was compared by using statistical full factorial *** experimental results show that the cement additive containing CaCl2and Ca(NO3)2can enhance early strength of cement ***,Ca(NO3)2is less effective than CaCl2even if it is combined with other organic chemicals such as alkanolamine and *** significant difference is found between CaCl2and Ca(NO3)2influencing the fluidity and 28 d strength of *** fluidity is determined by saccharide and its interaction with *** 28 d strength enhancement is determined by *** fluidity as well as the mechanical performance of treated cement can be significantly improved by combining Ca(NO3)2with TIPA and saccharide.

关键词： Portland cement cement additive accelerator type fluidity strength development full factorial design

Combustion Synthesis and Luminescent Properties of CaO: Eu^(3+), M^+ (M=Li, Na, K) Phosphor

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Journal of Wuhan University of Technology(materials science) 2010年第2期25卷 179-183页

作者：康明 college of material science and engineering Southwest University of Science and Technology

Li ^＋ , Na^ ＋ , or K ^＋ co-doped CaO： Eu^3＋ phosphors were prepared by the combustion synthesis method and characterized by X-ray diffraction （XRD）, photoluminescence and photolumi-nescence excitation （PL-PLE） spectra. The experimental results show that, upon excitation with 250 nm xenon light, the emission spectrum of the CaO： Eu^3＋ consists of 4f-4f emission transitions from the 5D0 excited level to the 7FJ （J=1, 2, 3） levels with the mainly electric dipole transition 5D0→7F2 of Eu3＋, indicating that the Eu^3＋ occupies a low symmetry. The charge-transfer band （CTB） shows somewhat red shift with the decreasing ionic radii of co-doped alkali metal ions. The PL and PLE intensities are significantly enhanced, especially the strongest intensity of luminescent is CaO： Eu^3＋, Li ＋ phosphor, when alkali metal ions are incorporated. The strongest peak of emission is slightly shifted from 614 to 593 nm, indicating that the Eu^3＋ ion locates in a symmetric position （Oh） when alkali metal ions are incorporated.

关键词： luminescence CaO: Eu^3+ combustion method

The frequencies of high frequency quasi-periodic oscillations in two different frames in black hole LMXBs

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Research in Astronomy and Astrophysics 2011年第11期11卷 1327-1335页

作者： Chang-Sheng Shi college of material science and Chemical engineering,Hainan University,Hainan 570228,China Key Laboratory of Modern Astronomy and Astrophysics,Nanjing University,Nanjing 210093,China college of material science and Chemical engineering Hainan University Hainan 570228 China Key Laboratory of Modern Astronomy and Astrophysics Nanjing University Nanjing 210093 China

We discuss the modes of the Alfvén waves in the accretion disk with a toroidal magnetic field in black hole low mass X-ray binaries in a rotating frame. By solving the perturbed general relativistic magnetohydrodynamic equations in the rotating frame, we find two stable modes of the Alfvén wave which are the same as those in the fiducial observer frame. This gives a feasible way to transform between the two different frames, which validates the possible Alfvén wave modes in the accreting celestial bodies with a toroidal magnetic field.

关键词： accretion accretion disks-magnetohydrodynamics-relativity