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145 results on '"Wan, Jianfeng"'

32. Phase-field simulation of magnetic field induced microstructure evolution in γMn-based alloys.

Author

Cui, Shushan, Wan, Jianfeng, Chen, Nailu, and Rong, Yonghua

Subjects
*MAGNETIC fields, *IRON-manganese alloys, *MAGNETIC structure, *MAGNETIC transitions, *MARTENSITIC structure, *MICROSTRUCTURE, *ANTIFERROMAGNETIC materials, *MAGNETIC domain
Abstract

γMn-based alloys mainly possess an antiferromagnetic martensitic structure at room temperature, in which the type of crystal structure changes with the magnetic structure. Therefore, it is commonly believed that the cubic–tetragonal structural transformation is caused by the magnetic transition. Due to small transformation distortion and high magnetic field being required to present strong magnetism, the microstructure evolution of γMn-based alloys under an external magnetic field has rarely been experimentally revealed. In this paper, a phase-field model based on the related antiferromagnetic energies is proposed to investigate the microstructure evolution during magnetization. The simulated results show that the microstructure after martensitic transformation exhibits a self-accommodated twinning pattern. Upon magnetic loading, two transition stages, i.e., the reorientation stage of antiferromagnetic domains and the antiferromagnetic–ferromagnetic transition stage, would successively appear. External stress directly affects the relative stability among martensitic variants, thereby indirectly influencing the magnetization behavior, and the effect is related to the stress direction. Although the microstructure changes with the external condition, the interfacial migration of martensitic variant domain (or the martensitic twin boundary) and magnetic domain could keep in accordance with each other due to the strong magnetoelastic coupling. [ABSTRACT FROM AUTHOR]

Published
2020
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40. Enhanced visible-light-driven photocatalytic performance of In2O3-loaded TiO2 nanocubes with exposed (001) facet

Author

Lin Bi-Zhou, Gao Bi-Fen, HU De-Sheng, Wan Jianfeng, and Chen Yi-Lin

Subjects
Photocurrent, Anatase, Materials science, Diffuse reflectance infrared fourier transform, Nanoparticle, Heterojunction, 02 engineering and technology, General Chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, chemistry.chemical_compound, Chemical engineering, chemistry, Photocatalysis, Rhodamine B, 0210 nano-technology, Visible spectrum
Abstract

The heterostructures of In2O3 nanoparticle loaded on anatase TiO2 nanocube with exposed (001) facet (In2O3/TiO2-nanocube) were fabricated via a two-step hydrothermal process. The crystal phase, morphology, microstructure and photo-absorption property of the products were characterized by FESEM, TEM, XRD, and UV-Vis diffuse reflectance spectroscopy. The results showed that the percentage of exposed (001) facet of TiO2 nanocube was about 33%. In2O3 nanoparticles were successfully decorated on the surface of TiO2 nanocube to form the In2O3/TiO2 heterojunction. Photocurrent measurements confirmed that (001) faceted surface was advantageous for the charge carrier migration and separation in the composites. In comparison with bare TiO2 nanocube and In2O3/TiO2-nanoparticle, the In2O3/TiO2-nanocube heterostructures exhibited enhanced activity toward the degradation of rhodamine B and tetracycline under visible light irradiation, which was attributed to the synergic effect of In2O3/TiO2 heterojunction and the exposure of (001) facet.

Published
2017

46. Is there TRIP effect? Verification from finite element simulation

Author

Rong, Yonghua, Chen, Nailu, Zuo, Xunwei, Wan, Jianfeng, and Feng, Rui

Subjects
transformation-induced plasticity (TRIP) effect, finite element simulation, strain-induced martensitic transformation, elongation, critical stress of martensitic transformation
Published
2016

48. Method Of Real-Time Assessing Of Life Of Hp Heater Tube-Plate In Power Plants

Author

Liu Junli, Meng Fanmao, Bi Wenyan, and Wan Jianfeng

Subjects
Engineering, Thermal fatigue, business.industry, assessing of life, loss life of thermal stress, On-line monitoring, Structural engineering, Automotive engineering, Power (physics), real-time computing, High pressure, General Earth and Planetary Sciences, Tube (fluid conveyance), life prediction, business, General Environmental Science
Abstract

In large power plants, in order to improve safety and stability of HP heaters(High Pressure) in operation, thicker tubeplates are designed and made, which will lead to more thermal stress between tube-plate and end-cover, furthermore, will reduce the thermal fatigue life of HP heaters sharply. so it is necessary to monitor the thermal fatigue its life. However, at presently a large portion of methods carry on calculating or analyzing beforehand or afterwords, which make effect of analyzing life being less greatly. In this paper, according to the theory of calculation of thermal fatigue life, real-time gathering tube-plate's temperatures, and computing the life everyday, provide the basis of operating and maintaining in the power plate.

Published
2011

50. Effect of Rare Earths on Electronic Structure of (110) Twin Martensite Boundary for Ni2MnGa Alloy

Author

Fei Yanqiong, Wan Jianfeng, and Wang Jiannong

Subjects
Materials science, Condensed matter physics, Doping, Relaxation (NMR), Ab initio, Boundary (topology), General Chemistry, Electronic structure, Condensed Matter::Materials Science, Crystallography, Geochemistry and Petrology, Martensite, Supercell (crystal), Crystal twinning
Abstract

The doping effect of rare earth elements (Tb and Sm) on the electronic structure of (110) martensitic twin boundary in Ni 2 MnGa alloys was investigated by using ab initio method within the DFT and the supercell implementation. The calculated results show that the atomic relaxation lowers the boundary energy and the segregation energy. Sm seems easier to segregate to the boundary and has a greater doping effect compared with Tb due to its lower segregation energy and bigger bonder order with neighboring atoms. Tb makes a greater contribution to the magnetic properties of the twin boundary than Sm.

Published
2006

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