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Raman Scattering and t-Phase Lattice Vibration of 3% (mole fraction) Y_2O_3-ZrO_2

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Journal of Materials Science & Technology 2004年第5期20卷 485-489页

作者： Xinglun TANG and Xinhua ZHENGSchool of Materials Science and Engineering, beijing Institute of Technology, beijing 100081, china Sch. of Mat. Sci. and Eng. Beijing Inst. of Technol. Beijing 100081 China

The Raman spectra of 3% (mole fraction) Y2O3-ZrO2 (3Y) are obtained at different temperature from 77 K to 853 K. The results show that 260 cm-1 Eg and 460 cm-1 Eg modes on the spectra shift toward lower wave number with the increase of temperature; meanwhile, the continuity of the Half Width at Half Maximum (HWHM) and wave number (frequency) of Raman bands are broken and t-phase only partially transforms to m-phase at 523 K. Based on the experimental results, this paper discusses the t-phase lattice vibration of 3Y and presents the images of vibration displacement of six Raman-active modes for t-phase of ZrO2. The analysis indicates that there are diversities existing in the displacement of the atomic vibration of Raman-active modes because of their different symmetries at various temperature, which leads to the different change tendencies of Raman bands. Furthermore, the abrupt changes of some Raman-active modes indicating the atomic displacement are assumed to be the condensations of phonon modes in the t→m phase transition.

关键词： Raman scattering Zirconia Phase transition Condensation of phonon

SUPERCONVERGENCES OF THE ADINI'S ELEMENT FORSECOND ORDER EQUATION

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Journal of Computational Mathematics 1999年第6期17卷 569-574页

作者： Ping Luo(Department of Computer Science and Technology, Qinghua University, beijing 100084,china)Qun Lin(Institute of Systems Science, Academia Sinica, beijing, 100080, china) Tsing Hua Univ Dept Comp Sci & Technol Beijing 100084 Peoples R China Acad Sinica Inst Syst Sci Beijing 100080 Peoples R China

n this papers the asymptotic error expansions of Adini's element for the secondorder imhomogeneous Neumann problem are given and the superconvergence estimations are obtained. Moreover, a numerical example to support ... 详细信息

关键词： Adini's element Superconvergence estimation Asymptotic expansion.

ANALYSIS OF DEPOSITED PRODUCTS AND REANODIZED POROUS LUBRICATING FILM ON A1 AFTER(NH_4)_2MoS_4 SOLUTION TREATMENT

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Acta Metallurgica Sinica(English Letters) 1993年第8期6卷 102-107页

作者： JIANG Guang WU Yinshun LI Jiuqing LIU Haiping University of Science and Technology beijing,beijing,china Department of Surface Sciences and Corrosion Engineering,University of Science and Technology beijing,beijing 100083,china beijing Univ of Science and Technology Beijing China

Observation was carried out of the structure of sulphuric,oxalic or phosphoric film on Al after treatment of reanodizing and electrolytic depositing lubricant in (NH_4)_2MoS_4 solution,as well as of the deposited products by means of EMPA,TEM and energy spectro-scopic *** deposited products are mixture of compounds of S and Mo rather than single MoS_2 and most of them dcposited near the surface layer of the *** regular long pores without barrier layer occurred in the film,but the regular fine channels without relation to the structural element parameters of original anodized film were found in the thickened barrier layer of phosphoric *** may be remained as Mo sulphide in the film during heating under Ar protective environment.

关键词： Al anodizing reanodizing lubricating film MoS_2

Kinetics of Carbide Layer Forming on the Surface of Steel in Molten Systems

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International Journal of Minerals,Metallurgy and Materials 1998年第2期12卷 75-79页

作者： Shuhuan Wang Shengwen Wu Shantong Jin Metallurgy School, UST beijing, beijing 100083, china Metallurgy School UST Beijing Beijing 100083 China

A mathematical model of kinetics of carbide layer formed on the surface of steel in fused system was set up with the theory of non-stable diffusion mass transfer and regular solution sub-lattice. This model was analyzed and testified by the experiments in which the VC layers were formed on four kinds of steels as steel 45,4Cr5MoSiV1,T10, and Cr12MoV immersed in the V_2O_5-Na_2O-B_2O_5 fused system with the reducing agent of *** results showed that there was a good agreement between the model and the experimental results;the growth speed of carbide layer depended on the factors of carbon activity in substrate, treatment temperature,kinds of carbides and its structure etc.

关键词： fused systern carbide layer treatment kinetics

Numerical Simulation of Shrinkage Cavity Formation in Spheroidal Graphite Iron Castings Based on Micro Modeling

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International Journal of Minerals,Metallurgy and Materials 1998年第1期12卷 9-12页

作者： Wenzhen Li Baicheng Liu Shantong Jin (Metallurgy Engineering School, University of Science and Technology beijing, beijing 100083, china)(Department of Mechanical Engineering, Tsinghua University, beijing 100084, china) Metallurgy Engineering School University of Science and Technology Beijing Beijing 100083 China Department of Mechanical Engineering Tsinghua University Beijing 100084 China

A micro-modeling method (MM) for the quantitative prediction of the shrinkage cavity formation in SGiron castings is proposed. The mathematical models describing the volume changes during the solidification ofspheroidal graphite cast iron are established based on the models of solidification kinetics. The shrinkage cavityformation of T-shaped SG iron castings is calculated with MM method. The calculated results are compared with theexperimental results. It is shown that the predicted size, shape and distribution of shrinkage cavity by MM methodare in good agreement with the measured results.

关键词： solidification shrinkage numerical simulation micro modeling spheroidal graphite cast iron

Assessment of the apparent activation energies for gas/solid reactions—carbonate decomposition

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Journal of University of Science and Technology beijing 2003年第2期10卷 25-29页

作者： Jianhua Liu and Jiayun ZhangMetallurgical Engineering School, University of Science and Technology beijing, beijing 100083, china Metall. Eng. Sch. Univ. of Sci. and Technol. Beijing Beijing 100083 China

The guidelines for assessing the apparent activation energies of gas/solidreactions have been proposed based on the experimental results from literatures. In CO_2 free inletgas flow, CaCO_3 decomposition between 950 and 1250 K with thin sample layer could be controlled bythe interfacial chemical reaction with apparent activation energy E = (215+-10) KJ/mol and E=(200+-10) kJ/mol at T = 813 to 1020 K, respectively. With relatively thick sample layer between 793and 1273 K, the CaCO_3 decomposition could be controlled by one or more steps involvingself-cooling, nucleation, intrinsic diffusion and heat transfer of gases, and E could vary between147 and 190 kJ/mol. In CO_2 containing inlet gas flow (5 percent-100 percent of CO_2), E wasdetermined to be varied from 949 to 2897 kJ/mol. For SrCO_3 and BaCO_3 decompositions controlled bythe interfacial chemical reaction, E was (213+-15) kJ/mol (1000-1350K) and (305+-15) kJ/mol(1260-1400 K), respectively

关键词： assessment activation energy decomposition carbonate

CONVERGENCE RATE OFDISTRIBUTIONS OF TRIMMED SUMS

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Chinese Annals of Mathematics,Series B 1996年第3期17卷 349-364页

作者： QI YONGCHENG CHENG SHIHONG(Department of Probability & Statistics, beijing University, beijing 100871, china) beijing UNIV DEPT PROBABIL & STATBEIJING 100871PEOPLES R CHINA

The authors first derive the normal expansion of the joint density function of two orderstatistics from the uniform distribution and then, using the approximation, establish a wayto estimate the normal convergence rate for trimmed sums. For applications, the convergencerates for the intermediately trimmed sums and heavily trimmed surns are found out.

关键词： Trimmed sum Order statistics Convergence rate Normal approximation

Boundedness for commutators of fractional Hardy operators on Herz spaces

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Progress in Natural Science:Materials International 2007年第1期17卷 20-25页

作者： FU Zunwei, LIU Zongguang and LU Shanzhen ( School of Mathematical Sciences, beijing Normal University, beijing 100875, china Department of Mathematics, Linyi Normal University, Linyi 276005, china Department of Mathematics, china University of Mining and Technology, beijing 100083, china) [a]School of Mathematical Sciences Beijing Normal University Beijing China [b]Departhent of Mathematics Linyi Normal University Linyi China [c]Departhent of Mathematics China University of Mining and Technology Beijing China

Some boundedness results are established for commutators generated by classical fractional Hardy operators and one-sided CMO functions on the homogeneous Herz spaces, which extends some known results.

关键词： fractional Hardy operator Hardy’s integral inequality commutator one-sided CMO function homogeneous Herz space.

PARALLEL ROSENBROCK METHODS FOR SOLVING STIFF SYSTEMS IN REAL-TIME SIMULATION

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Journal of Computational Mathematics 2000年第4期18卷 375-386页

作者： Li-rong Chen De-gui Liu (beijing institute of Computer Application and Simulation Technology, beijing 100854, china) 北京计算机应用与仿真技术所北京 100854

In this paper parallel Rosenbrock methods in real-time simulation are presented on parallel computers. Their construction, their convergence and their numerical stability are studied, and the numerical simulation expe... 详细信息

关键词： Rosenbrock methods stiff system real-time simulation parallel algorithms