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Your search keyword '"Li, Qifeng"' showing total 25 results
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25 results on '"Li, Qifeng"'

17. Preparation and Thermal Conductivity of Epoxy Resin/Graphene-Fe3O4 Composites

Author

Yida Deng, Da-Hai Xia, Zhenbo Qin, Li Qifeng, Zhong Wu, Chen Jingyun, and Yiwen Zhang

Subjects
Technology, Materials science, Electronic packaging, 02 engineering and technology, 010402 general chemistry, EP/GR-Fe3O4 composites, 01 natural sciences, Article, orientation, law.invention, Matrix (chemical analysis), Thermal conductivity, law, General Materials Science, Thermal stability, thermal conductivity, Composite material, Microscopy, QC120-168.85, Graphene, QH201-278.5, Epoxy, 021001 nanoscience & nanotechnology, Engineering (General). Civil engineering (General), magnetic GR, 0104 chemical sciences, Magnetic field, TK1-9971, Descriptive and experimental mechanics, visual_art, visual_art.visual_art_medium, Electrical engineering. Electronics. Nuclear engineering, TA1-2040, 0210 nano-technology
Abstract

By modifying the bonding of graphene (GR) and Fe3O4, a stable structure of GR-Fe3O4, namely magnetic GR, was obtained. Under the induction of a magnetic field, it can be orientated in an epoxy resin (EP) matrix, thus preparing EP/GR-Fe3O4 composites. The effects of the content of GR and the degree of orientation on the thermal conductivity of the composites were investigated, and the most suitable Fe3O4 load on GR was obtained. When the mass ratio of GR and Fe3O4 was 2:1, the thermal conductivity could be increased by 54.8% compared with that of pure EP. Meanwhile, EP/GR-Fe3O4 composites had a better thermal stability, dynamic thermomechanical properties, and excellent electrical insulation properties, which can meet the requirements of electronic packaging materials.

Published
2021

22. Preparation and Mechanical Properties of Layered Cu/Gr Composite Film

Author

Yiwen Zhang, Chen Jingyun, Wenbin Hu, Zhenbo Qin, Yida Deng, Zhong Wu, Da-Hai Xia, and Li Qifeng

Subjects
Materials science, Structure analysis, Stacking, Composite film, 02 engineering and technology, mechanical properties, 010402 general chemistry, 01 natural sciences, Layered structure, law.invention, Metal, Molecular dynamics, law, Materials Chemistry, Composite material, Graphene, Surfaces and Interfaces, Engineering (General). Civil engineering (General), 021001 nanoscience & nanotechnology, 0104 chemical sciences, Surfaces, Coatings and Films, molecular dynamics simulation, visual_art, visual_art.visual_art_medium, TA1-2040, 0210 nano-technology, Layer (electronics), Cu/Gr composite films
Abstract

Graphene (Gr) has proved its significant role as a reinforcement material in improving the strength of metal matrix composites due to its excellent mechanical properties. In this paper, Gr/Cu composite film with a layered structure was prepared by layering electrodeposition. The directional distribution of Gr in the Cu film was insured by this method, which gives play to its ultra-high-strength in a two-dimensional plane. In the meantime, the effect of electrodeposition time on the distribution structure of the Gr layer was studied. The structure analysis and mechanical properties test show that the strength of the layered Gr/Cu composite film is greatly improved compared to the pure Cu film. Furthermore, the strength of the composite film increases at the beginning and then decreases with the electrodeposition time of the Gr layer increasing, while the coverage and the degree for the layer stacking of Gr gradually increase in this process. In conclusion, the influence of different Gr distributions on the mechanical properties of the composite film has been studied by combining the experimental results with molecular dynamics simulation, which lays an effective foundation for further optimizing the structure of Gr in the layered composite film and improving the mechanical properties.

Published
2021

25. A Clean and Health-Care-Focused Way to Reduce Indoor Airborne Bacteria in Calf House with Long-Wave Ultraviolet.

Author

Ding L, Zhang Q, Wang C, Yao C, Shan F, and Li Q

Abstract

Long-term exposure to a relatively high concentration of airborne bacteria emitted from intensive livestock houses could potentially threaten the health and welfare of animals and workers. There is a dual effect of air sterilization and promotion of vitamin D synthesis for the specific bands of ultraviolet light. This study investigated the potential use of A-band ultraviolet (UVA) tubes as a clean and safe way of reducing airborne bacteria and improving calf health. The composition and emission characteristics of airborne bacteria were investigated and used to determine the correct operating regime of UVA tubes in calf houses. Intermittent exceedances of indoor airborne bacteria were observed in closed calf houses. The measured emission intensity of airborne bacteria was 1.13 ± 0.09 × 10 7 CFU h -1 per calf. Proteobacteria were the dominant microbial species in the air inside and outside calf houses. After UVA radiation, the indoor culturable airborne bacteria decreased in all particle size ranges of the Anderson sampler, and it showed the highest reduction rate in the size range of 3.3-4.7 μm. The results of this study would enrich the knowledge of the source characteristics of the airborne bacteria in intensive livestock farming and contribute to the environmental control of cattle in intensive livestock production.

Published
2024
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