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Research Status of DME Fuelled Diesel Engine in China
Zhou Longbao,Wang Ying,Wang Xibin,Pan Keyu,Jiang Deming 한국자동차공학회 2004 한국자동차공학회 Workshop Vol.2004 No.-
This paper mainly introduces the energy status, the necessity and importance of developing alternative fuel powered engine in China. DME is one of the most promising alternative fuels for diesel engine due to its excellent chemical and physical properties. Power output of DME engine can exceed that of the diesel engine. Emission results from ESC test cycles indicate that NOx.HC and PM emissions of CA498 DME engine all meet Euro Ⅲ regulation, excluding CO emission.
Improvement of Glass Formability in Ultrasonic Vibration Assisted Molding Process
Tianfeng Zhou,Jiaqing Xie,Jiwang Yan,Kuriyagawa Tsunemoto,Xibin Wang 한국정밀공학회 2017 International Journal of Precision Engineering and Vol.18 No.1
Micro optical elements with complex shapes are needed increasingly in optical, optoelectronic and biomedical industries. Since glass molding process is an effective approach to fabricate microstructures, and its surface quality strongly depends on the filling capacity of glass at high temperature. To improve the formability and reduce adhesion between the glass and the mold at high temperature, ultrasonic vibration is applied to improve the formability in the molding process. Fundamental experiments are carried out to test the effectiveness of ultrasonic vibration on friction force decrease and a bonding model on the glass-mold interface at elevated temperature is proposed. Finite element method (FEM) simulation and glass molding experiments are conducted to evaluate the improvements of material formability brought about by ultrasonic vibration. The results show that the ultrasonic vibration can significantly lower the friction force and increase the glass formability.
Micro Convexity Elimination of Tungsten Carbide in Electrical Discharge Milling for Lens Moulds
Tianfeng Zhou,Si-Bo Wang,Xin Liu,Zhi-Qiang Liang,Xibin Wang 한국정밀공학회 2017 International Journal of Precision Engineering and Vol.18 No.12
Electrical discharge milling (ED milling) using spherical electrode is considered to fabricate tungsten carbide (WC) lens moulds for high volume and cost efficient mass production comparing with hemispherical electrode whose wear is noticeably larger. However, micro convexity with dome shape generating in the center of the mould leads to poor surface quality of moulds when using spherical electrode. Therefore, based on boundary layer theory, the forming mechanism of the micro convexity is analyzed in detail by measuring its height and profile by virtue of 3D laser scanning microscope and scanning electron microscope (SEM). The relationship between the boundary layer thickness and the discharge gap is subsequently established, which can be utilized to reduce the convexity to improve the surface quality of lens mould. Then a method to eliminate the micro convexity is proposed. In addition, experiments of different discharge gaps were carried out to confirm the boundary layer theory. Results show that the height of micro convexity can be reduced to 4 μm when the discharge gap was specified to the boundary layer thickness at certain rotational speed.
Qian Yu,Tianfeng Zhou,Yupeng He,Peng Liu,Xibin Wang,Jiwang Yan 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.7
Relative tool sharpness (RTS) is identified as the ratio of undeformed chip thickness to tool cutting edge radius. This paper studies the effects of RTS on the surface generation mechanism of precision turning of electroless nickel-phosphorus (Ni-P) coating. An Rshaped tungsten carbide (WC) tool was adopted for the face turning experiment. The cutting edge radius was 1.84 μm measured by a laser scanning confocal microscope (LSCM). The chip formation behavior, cutting forces and surface morphology were investigated under different RTS values. Results showed that the chip changes from continuous to discontinuous as RTS decreases from 0.54 to 0.27, indicating the transition of the material removal mechanism. The periodical fluctuations with small amplitudes on the machined surface are associated with the high-frequency tool-tip vibration. The low-frequency fluctuations of the cutting forces are related to the material swelling and recovery. The optimal machined surface roughness was obtained at the RTS of 0.38.
Joint Deployment of Small Cells and Wireless Backhaul Links in Next-Generation Networks
Xiangxiang Xu,Saad, Walid,Xiujun Zhang,Xibin Xu,Shidong Zhou IEEE 2015 IEEE communications letters Vol.19 No.12
<P>In this letter, a novel approach for optimizing the joint deployment of small cell base stations and wireless backhaul links is proposed. This joint deployment scenario is cast as a multiobjective optimization problem under the constraints of limited backhaul capacity and outage probability. To address the problem, a novel adaptive algorithm that integrates E-method, Lagrangian relaxation, and tabu search is proposed to obtain the Pareto optimal solution set. Simulation results show that the proposed algorithm is quite effective in finding the optimal solutions. The proposed joint deployment model can be used for planning small cell networks.</P>
Tao Shao,Dehong Bai,Mingzhu Qiu,Yu Li,Qiankun Zhang,Ziyu Xue,Shijie He,Dongxia Zhang,Xibin Zhou 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.108 No.-
Facile synthesis of more dendritic and uniform Pt-based nanostructures with carbon materials couldgreatly reduce cost and increase Pt utilization for methanol oxidation reaction (MOR) in direct methanolfuel cell (DMFC). This study reports a novel one-pot method to fabricate AgPt nano-pompons (AgPt NPs)with the guidance of N-GQDs through AA reduce the precursor of Ag and Pt. Morphology characterizationdescribes N-GQDs as morphology guiding and dispersing agents to regulate the dendrite formation ofnano-pompons. Under the optimized conditions, the AgPt NPs (Ag1Pt2) display above 11 times improvementin electrocatalytic activity and higher stability for the MOR compared with Pt/C catalysts. Densityfunction theory (DFT) studies prove that the introduction of Ag can greatly enhance the adsorption of COon Pt and promote the transformation of CO to COOH. The facile synthetic method and excellent MORperformance endow AgPt NPs with great application prospect in DMFCs as an anode catalyst.