Papers by Author: Ling Chen

Abstract: Existing auto after-sales service recommendation only based on user' history behavior, and doesn't take user's real-time location into account, and the recommended result doesn’t meet user’s needs well. Aiming at the problem of traditional recommendation, put forward the personalized recommendation method based on LBS. This method takes the user as the core, by analyzing user's real-time behavior, historical behavior and the user's real-time geographic location, speculated the user's current needs, and recommend accurate information for them.

Abstract: The polytetrafluoroethylene (PTFE) matrix composites which filled with polyphenylene sulfide (PPS) fiber, poly-p-phenelenferephthalamide (PPTA) fibre or glass fiber (GF)) and graphite at various mass fractions were prepared by the processes of mechanical blending, compression molding and sintering. The mechanical properties of the composites, such as tensile strength, impact strength and hardness were investigated. The results show that tensile strength and elongation at break markedly decrease but elasticity increases by filling with fibers. Impact strength decreases by filling with PPS and GF, and the composite displays brittle characteristic. However, the impact strength rapidly increases by filling with PPTA fiber. Hardness increases with the fibers content increases, and decreases with graphite content increases. Filling graphite into PTFE has light effect on the impact and tensile strength of composites. The tribological properties of the composites were investigated on M-2000 wear tester at dry friction condition. The wear mechanism was also discussed and the wear surfaces were examined by SEM. The result indicates that fibers which diffused in PTFE matrix wind with PTFE molecule chain, and then form grid structure. The load-bearing capacity of composites can be obviously enhanced and the trend of block fragmentations slide is inhibited, so that the tribological properties are improved markedly.

Abstract: Arc ion plating(AIP) has higher deposition rates, whereas macro-particles (MPs) make the film properties decreasing. In this paper, AIP with or without magnetic filter (MF or AIP) and composition of AIP followed with magnetic filter (MFAIP) were designed to deposit TiN films on silicon (Si) and high-speed steel(HSS), respectively. Scanning electron microscope (SEM), nanoindentation and microscratch tests were investigated. SEM showed that both the MF and the MFAIP films had a superfine layer among the columnar crystals grown vertically against substrate surface. However, the columnar crystals of MF films were leptosomatic and well-orientational, while MFAIP ones were coarse and short, and even ragged in size and orientation. Nanoindentation test results showed the highest hardness for MF films and the lowest one for AIP films. A new parameter Scratch Crack Propagation Resistance (CPRs) was introduced to evaluate the film adhesion properties in a scratch test. MF films had the highest adhesion. AIP films were most susceptible to failure as the CPRs was the lowest, although the Lc1 was higher than MFAIP ones. It was proposed that the MPs were effectively removed with the MF, and the MF layers were superfine to improve the properties of the films.