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RISS 인기검색어
- 검색키워드
- 저자 : Jifeng Cheng (검색결과 3 건)
- 무료
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Xiaomei Zhan,Jifeng Cheng,Li Xiang,Huiju Shao,Shuhao Qin 한국섬유공학회 2021 Fibers and polymers Vol.22 No.5
To obtain the excellent permeate flux, rejection performance and mechanical properties, the chlorinated polyvinylchloride (CPVC) porous membrane was fabricated on the polyethylene terephthalate (PET) non-woven fabric by non-solventinduced phase separation (NIPS), using Tween80 (polyoxyethylene sorbitan monooleate) as a hydrophilic surfactant to regulate themicrostructure of the membrane. Porous skin layer and sub-layer were achieved when 3 wt.% Tween80 was added with asmall amount of deionized water as additive, and internal layer consisted of various finger-like holes. The forming mechanism ofmicrostructures was investigated according to the effects of Tween80 molecular chain structure on the viscosity and surface tensionof casting solution. Significantly, the modified membranes obviously exhibited higher pure water flux, which was increasedby 257 % compared with the pristine membrane. The rejection to ink suspension was over 99 %. Furthermore, the antifoulingperformance of modified membrane was also greatly improved on account of the above microstructure and more hydrophilicsurface. This study provides a new idea for the construction of membrane microstructure and the hydrophilic modification.
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Xiao Wu,Huiju Shao,Jifeng Cheng,Dongdong Kang 한국섬유공학회 2022 Fibers and polymers Vol.23 No.5
To optimize the mechanical properties of polymeric membranes fabricated by non-solvent induced phaseseparation (NIPS), a non-woven fabric has been used to reinforce the composite membrane. However, it remains a challengeto prepare an intact polymer membrane on the non-woven fabric because casting dopes usually spread into the poroussubstrate. Herein, a kind of non-woven fabric reinforced poly(vinylidene fluoride) (PVDF) composite membrane wasfabricated by using poly(vinyl pyrrolidone) (PVP) to control the viscosity of casting dopes. Additionally, the effects of nonwovenfabric on the membrane structure and properties were explored in the light of dynamics during the phase inversionprocess. A porous skin layer and long finger-like pores were successfully created on the surface and inner of membraneswhen 6 wt% PVP was added in the casting dopes. Compared with pure PVDF membranes, the pure water flux of the resultantmembrane was elevated from 49.9 L/m2h to 656 L/m2h, BSA rejection from 40.5 % to 86.4 %, and flux recovery ratio (FRR)from 58.7 % to 86.1 %. More importantly, it also possessed outstanding mechanical properties, which far outperforms theresults reported in some literatures. This study suggests a promising strategy to fabricate PVDF composite membranes withpreeminent properties for wastewater treatment.
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Research on influence of harmonic wear wheel on wheel/rail contact geometry of high-speed train
Qian Xiao,Zhixiang Luo,Xu Xu,Jifeng Zheng,Shu Cheng 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.2
Harmonic wear is one of the common wear phenomena of high-speed train wheels. The change of wheel/rail rolling contact geometry leads to unstable characteristics of wheel/rail contact, which directly affects the quality and safety of high-speed train operation. Because wheelset lateral displacement directly affected the wheel/rail contact geometry, in this paper, the UM software was used to establish a high-speed train vehicle-track coupled dynamics simulation model of the CRH2 (China Railway High-speed 2) head car. Lateral displacement of harmonic wear wheel was calculated under different wear condition to analyze the influence of harmonic wear wheels on wheelset lateral displacement. Then according to macroscopic dimension change of the wheel profile from lateral and radial directions of high-speed train induced by harmonic wear wheels, wheel profiles under different wear condition were selected. And wheel/rail contact geometry under different harmonic wear stages was calculated to discuss the influence of harmonic wear wheel on wheel/rail contact geometry. The results show that harmonic order and wave depth of harmonic wear wheel have small influence on the lateral displacement of wheelset, but the influence of wave depth is greater than harmonic order. The average difference of lateral displacement between harmonic wear wheel and no harmonic wear wheel increases with the increase of wave depth and order. In a harmonic wave length, the maximum value of both equivalent conicity and contact angle appear in deepest wave depth. The greater the wave depth, the more obvious the fluctuations, and equivalent conicity changes are less obvious.
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