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Yang B.,Southwest University of Science and Technology | Wang L.-G.,Southwest University of Science and Technology | Yi Y.,Southwest University of Science and Technology | Yi Y.,State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials | And 2 more authors.
Wuli Xuebao/Acta Physica Sinica | Year: 2015

Based on the density functional theory, the diffusion behaviors of C, N and O atoms in V metal are studied by using the first-principles calculation method. Firstly, the site occupations of C, N and O atoms in the interstitials of the bcc V lattice are discussed. The interactions of interstitial C, N and O atoms with V lattice are analyzed, and the influence of the electronic structure on the interaction is explored. The study results show that C, N and O atoms are more stable in octahedral interstice of V metal, and a relatively strong bonding interaction is formed between their 2p-electron and the 3d-electron of V metal. The diffusion barriers of C, N and O atoms are 0.89 eV, 1.26 eV and 0.98 eV, respectively. Thus, the expressions of their diffusion coefficients are obtained. Finally, the diffusion coefficients of C, N and O atoms are compared by the Arrhenius plot. Their diffusion coefficients are calculated at 500-1100 K, and the calculation results are consistent with experimental values. © 2015 Chinese Physical Society. Source


Xia Y.,Southwest University of Science and Technology | Yan Y.,State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials | Hu Z.,State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials
Construction and Building Materials | Year: 2013

Circulating fluidized bed combustion (CFBC) fly ash (CFA) is an industrial waste from CFBC boiler of electric power plant, which is not a good supplementary cementitious material for Portland cement and concrete because its expansive feature results in unexpected deterioration of concrete in the last stage. The non-autoclaved aerated concrete (NAAC) was developed using the CFA as main raw materials in this study. To find out the effect of raw materials on the products properties, rheological property of fresh pastes, physical, chemical, mechanical and microstructure analyses were performed. The results show the reasonable dosage of CFA, cement, and lime were 65.5%, 22%, and 10%, respectively. Medium diameter of CFA particle size ranges from 9.6 μm to 23.9 μm is the most suitable for preparation of NAAC duo to the matching condition between thickening rate of the slurry and the reaction rate of aluminum powder and water. The principal minerals in NAAC are needlelike AFt and floccular C-S-H, be different from autoclaved aerated concrete (AAC). © 2013 Published by Elsevier Ltd. Source


Li T.,University of Sichuan | Li T.,State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials | Liu Y.,University of Sichuan | He D.,Mianyang Normal University | Ma G.,State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials
Xiyou Jinshu Cailiao Yu Gongcheng/Rare Metal Materials and Engineering | Year: 2012

Through a mild thermal precipitation and aging process, hydrated cobalt oxalate nanorods were synthesized using CoSO 3 and (NH 4) 2 C 2O 4·H 2O as raw materials at the reaction and aging temperature of 65°C. Afterwards, the metal cobalt nanofibres were prepared by decomposition of cobalt oxalate nanorods precursor in Ar gas atmosphere. The composition and morphology of products were characterized by means of atomic absorption spectrometer (AAS), organic elemental analyzer (OEA), Fourier transform infrared spectroscopy (FT-IR), thermogravimetry analysis and derivative thermogravimetry (TGA-DTG), the X-ray diffraction (XRD), and scanning electron microscope (SEM). The results demonstrate that the product is hydrated cobalt oxalate, and the chemical formula CoC 2O 4·3H 2O is confirmed. The sizes of the cobalt oxalate nanorods as-prepared are about 0.2-0.4 μm in diameter, and 1.0-5.0 μm in length; the metal nanofibres prepared via decomposition process of hydrated cobalt oxalate nanorods are about 0.2 μm in diameter, and 1.0-5.0 μm in length. Copyright © 2012, Northwest Institute for Nonferrous Metal Research. Published by Elsevier BV. All rights reserved. Source


Li T.,Sichuan University | Li T.,State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials | Liu Y.,Sichuan University | Ma G.,State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials | He D.,Mianyang Normal University
Journal Wuhan University of Technology, Materials Science Edition | Year: 2013

Nickel tartrate precursor particles were synthesized by the liquid phase precipitation method in an ethanol-water-ammonia mixed solution, with tartaric acid and using nickel chlorate as raw materials, with the pH value controlled at 4.0, and the temperature controlled at 50 C. Nickel particles with complicated morphology were prepared by the decomposition of nickel taratrate precursor particles at temperatures of 360, 380 and 400 C, respectively. The study of infrared spectroscopy (IR) indicated that the product was pure nickel tartrate. The studies of the atomic absorption spectrometry (AAS) and organic elemental analysis (OEA) indicated that the molar ratio of Ni2+ to (C 4H4O6)2- is close to 1:1. The studies of the differential scanning calorimeter and thermo-gravimetric analysis (DSC-TG) indicated that the chemical formula Ni2(C4H 4O6)2·5H2O was confirmed. The studies of X-ray diffractions (XRD) indicated that the silvery white metal powders were pure Ni, with a face-centered cubic crystal structure. The images of scanning electron microscopy (SEM) showed that the morphology of metal Ni particles was obvious spherical and radiate. The diameter of nickel tartrate particles was about 60 μm, which consisted of many nanolathes; and the diameter of metal Ni particles was about 30 μm, which consisted of many lathes about 0.5 μm in thickness. © 2013 Wuhan University of Technology and Springer-Verlag Berlin Heidelberg. Source


Chen X.,State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials | Yan Y.,Southwest University of Science and Technology | Liu Y.,State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials | Hu Z.,State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials
Construction and Building Materials | Year: 2014

Circulating fluidized bed combustion (CFBC) fly ash (CFA), which has not been recycled in large scale due to its later volume expansion yet, was utilized for the preparation of foam concrete. To investigate whether a large volume of pore in the foam concrete would reduce the expansion from the CFA or reduce the shrinkage of foam concrete. A series of manufacturing parameters, such as quick lime and aluminate cement dosages, water to solid ratio (W/S), CFA fineness and type, chemical activators and so on, were investigated based on the density and compressive strength of specimens and the performances of products were also tested in this paper. The results show the most reasonable dosages of CFA, quick lime, and aluminate cement were 70%, 8%, and 2%, respectively. The addition of quicklime or/and aluminate cement could accelerate the setting and hardening rate of slurry. To improve the compressive strength, the finer CFA is better, and W/S should be reduced as low as possible. Incorporating 0.05% TEA or/and 0.5% Na2SO4 into the slurry can significantly enhance the compressive strength of the foam concrete. Encouragingly, the compressive strength, frost-resistance and thermal conductivity of products are good. © 2013 Elsevier Ltd. All rights reserved. Source

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