检索结果-南通市图书馆

Synthesis and photocatalytic properties of lanthanum doped anatase TiO_2 coated Fe_3O_4 composites

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2011年第3期30卷 252-257页

作者： Zhongliang Shi Xiaoyan Zhang Shuhua Yao shenyang univ Chem technol Sch Appl Chem Shenyang 110142 Peoples R China

A composite photocatalyst （La/TiO2/Fe3O4） with a lanthanum doped TiO2 （La/TiO2） shell and a magnetite core was prepared by coating photoactive La/TiO2 onto a magnetic Fe3O4 core. The morphological, structural, and optical properties of as-prepared samples were charac-terized by transmission electron microscopy （TEM）, X-ray diffraction （XRD） and UV-vis absorption spectroscopy. The effect of lanthanum content on the photocatalytic properties was studied, and the result revealed that 0.15 mol% La/TiO2/Fe3O4 exhibited the highest photoactiv-ity. The photocatalytic properties of the prepared photocatalyst under UV and visible light were investigated in aqueous solution using methyl orange （MO） as a target pollutant. The results showed that the prepared photocatalyst was activated by visible light and used as an ef-fective catalyst in photooxidation reactions. In addition, the possibility of cyclic usage of the prepared photocatalyst was also confirmed. Moreover, La/TiO2 was tightly bound to Fe3O4 and could be easily recovered from the medium by a simple magnetic process.

关键词： titanium dioxide magnetite lanthanum doping photocatalytic activity methyl orange

Numerical model of solidification process in binary Al Fe alloy under centrifugal casting

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 2000年第5期10卷 614-618页

作者：李荣德马冰徐玉桥 shenyang univ technol Sch Mat Sci & Engn Shenyang 110023 Peoples R China

During the solidification process of binary Al Fe alloy under centrifugal casting, the primary phase of Al 3Fe migrates along the radius because of the density difference between the primary phase and the liquid alloy. Therefore the temperature and concentration field are affected significantly by both the fluid flow and the solid phase migration. In order to take this factor into consideration, a two phase flow numerical model has been established in column coordinate to depict the solidification process of Al Fe alloy under centrifugal casting according to the feature that there exists the solid phase migration during the process. Thus the solidification process of Al Fe alloy under centrifugal casting has been described much more pertinently. [

关键词： centrifugal casting Al Fe alloy two phase flow numerical model

Revision of a CCT Diagram of the Simulated ADI Weld Metal and Its Application in Actual Welding

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & technology 1998年第2期14卷 147-150页

作者： Li, Deyuan Zhou, Zhenfeng Sun, Daqian Shao, Chengji Jilin univ technol Changchun 130025 Peoples R China shenyang Polytech univ Shenyang 110023 Peoples R China

A continuous cooling transformation (CCT) diagram of the simulated austempered ductile iron (ADI) weld metal has been developed by means of the Formastor-F diagram measurement apparatus, and revised by comparing with the actual welding. Finally, the revised diagram was used to determine the welding technology. (Edited author abstract) 4 Refs.

关键词： Iron alloys

Effects of Solution Temperature on Tensile Properties ofSiC_w/2024Al Composite

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & technology 1995年第4期11卷 291-294页

作者： MA, ZY LU, YX LUO, M BI, J ZHANG, YZ NE univ technol SHENYANG 110006PEOPLES R CHINA

The effects of solution (quench) temperature on the properties of SiCW/Al composite have been investigated using tensile tests. The experiments indicate that the solution temperature of the composite fabricated by P/M technique can be raised to 560 degrees C. The tensile strength of the composite is obviously dependent on solution (quench) temperature and the composite solutionized at 540 degrees C exhibits a maximum of tensile strength and elongation-to-failure. These results can be accounted for by the variation of the dislocation density in the composite.

关键词： Metallic matrix composites

Study on Modification Mechanism of Rare Earth in ZA27 Cast Alloy with Electronic Theory and Molecular Dynamics Method

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & technology 2004年第5期20卷 586-588页

作者： Guili LIU, Rongde LI and Zhenping ZHOUSchool of Materials Science and Engineering, shenyang university of technology, shenyang 110023, China Sch. of Mat. Sci. and Eng. Shenyang Univ. of Technol. Shenyang 110023 China

A model of liquid ZA27 cast alloy is established according to molecular dynamics theory and an atomic structural model of co-existent a phase and liquid is also presented by means of computer programming. Recursion method is adopted to calculate the electronic structure of RE (rare earth) in grains and around phase boundaries respectively. The calculation shows that RE is more stable around phase boundaries than in grains, which explains the fact that the solution of RE in a phase is less, and RE mainly aggregates in front of phase boundary. The calculations of bonding order integrals also show that RE in front of phases hardly solidify onto the grain surfaces as active element so as to prevent grains growth and refine the grains. As a result, the modification mechanism of RE may be explained from the view of electronic structure.

关键词： Atomic structural model Recursion method Electronic structure Modification mechanism Rare easth

Calculation of Phase Equilibria between Solid Solutions with Magnetic Transition by the Cluster Variation Method

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & technology 1997年第1期13卷 15-20页

作者： Liu, XJ Jiang, M Hao, SM Yuan, RW NE univ technol DEPT MAT SCI & ENGNSHENYANG 110006PEOPLES R CHINA

By using the geometric analysis of grand potential, the molar grand potential-effective chemical potential curve of solution with magnetic transition can be obtained from the relevant molar free energy diagram, and it is shown that the grand potential and effective chemical potential can be separated into paramagnetic and magnetic terms. In addition, the CVM has been combined with the present magnetic transition free energy model such as M. Hillert and T. Nishizawa's models to calculate phase equilibria between solutions with magnetic transition, and this combined method has been applied to the alpha/gamma phase equilibrium in the Fe-Mn binary system and found to be feasible.

关键词： Iron alloys

Synthesis and luminescence properties of nanocrystalline Gd_3Ga_5O_(12):Eu^(3+) by a homogeneous precipitation method

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2012年第6期31卷 599-603页

作者： Li Yanhong Lu Haiyan Zhang Yongming Ma Jing Song Guoyi shenyang univ Chem technol Sch Mat Sci & Engn Shenyang 110142 Peoples R China

Nanocrystalline Gd3Ga5O12:Eu3+ with cubic phase was prepared by a urea homogeneous precipitation method. X-ray diffraction (XRD), field emission scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), thermo-gravimetric and differential thermal analysis (TG-DTA) and photoluminescence spectra were used to characterize the samples. The effects of the initial solution pH value and urea content on the structure of the sample were studied. The XRD results show that pure phase Gd3Ga5O12 can be obtained at pH =6 and pH =8 of the initial solution. The average crystallite size can be calculated as in the range of 24~33 nm. The average crystallite size decreases with increasing molar ratio of urea to metal ion. The results of excitation spectra and emission spectra show that the emission peaks are ascribed to 5D0→7FJ transitions of Eu3+, and the magnetic dipole transition originated from 5D0 →7F1 of Eu3+ is the strongest; the broad excitation bands belong to change transfer band of Eu?O and the host absorption of Gd3Ga5O12. An efficient energy transfer occurs from Gd3+ to Eu3+.

关键词： Gd3Ga5O12:Eu3+ nanocrystal urea homogeneous precipitation method luminescence

Rare Earth Effects on Adhesion of Cr_2O_3 Oxide Scale Formed on Surface of Co-40Cr Alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2001年第1期19卷 34-39页

作者：靳惠明张林楠李美栓李铁藩 shenyang univ technol Lab Corros & Protect Shenyang 110023 Peoples R China Chinese Acad Sci Inst Corros & Protect Met State Key Lab Corros Sci Shenyang 110015 Peoples R China

Isothermal and cyclic oxidation behaviors of Co 40Cr alloy at 1000 ℃ in air were studied. Scanning electron microscopy (SEM) was used to examine the oxide scale formed on the surface of the alloy. By comparing the oxidation behaviors of Co 40Cr alloy and its 3×10 16 and 3×10 17 Y +/cm 2 implanted specimens, it was found that the resistant to oxidation property of Co 40Cr was greatly improved due to the implantation of yttrium. Acoustic emission was used to study the distribution of defects at the interface between the scale and alloy. Raman spectrum was also used to study the stress status in chromic scale formed on the surface of Co 40Cr with and without yttrium. The main reason for the improvement of resistant to oxidation property of Y doped Co 40Cr probably is that yttrium can segregate to Cr 2O 3 grain boundaries and change the scale′s growing mechanism and mechanical property. Most importantly, Y implantation decreases the size and number of interfacial defects and the residual stress in the scale, and remarkably enhances the adhesion of chromia scale with Co 40Cr substrate.

关键词： rare earths adhesion oxidation acoustic emission Raman spectrum

Ligand Substituent Electronic Effect in Ternary Complexes—— Systems of Zn2+(Cd2+)-bipy(phen)-substituted Salicylic Acid System

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1994年第13期39卷 1101-1105页

作者：高恩君原晓红刘祁涛 shenyang INST CHEM technol DEPT FINE CHEM TECHNOLSHENYANG 110221PEOPLES R CHINA

Research has been done on the cooperating effect of π electronic transformation between the ligands in some transition metal ternary complexes. The effect can remarkably affect the stability of ternary complexes. For... 详细信息

关键词： ternary complexes electronic effect stability.