Papers by Author: Wen Jie Zhai

Abstract: The tribo-electrochemical performance of polycrystalline silicon was studied by Tafel polarization curves and electrochemical impedance spectroscopy (EIS), based on which the electrochemical mechanical planarization (ECMP) simulating test was done to investigate the effects of applied potentials on friction and material removal rate (MRR) with an ECMP simulating tester. According to the research, a suitable anode polarization potential is advantageous to promote the forming of passivation film with better corrosion inhibition in alkaline CeO₂ polishing liquid, and forming of passivation film on silicon surface can increase both the friction between polishing pad and specimen and the MRR of silicon. This result provides theoretical supports and experimental bases for ECMP of silicon wafer to increase its polishing efficiency.

Abstract: The wear-resisting function of the 4-10mm thickness Ultra high molecular weight polyethylene artificially acetabulum was researched, which matches up with the 28mm-diameter artificial thigh bone. The Elastic deformation theory and the finite-element analysis to get the regularity of distribution on contract stress were compared, calculate the stress integral to friction journey during the normal gait, and according with the Archard wear calculation formula, compare the reckoning of artificially acetabulum in different thickness. By this calculation, the regularity of distribution for contact stress, which got from elastic deformation theory, is close to the result got from finite-element analysis. For a 65 kg sufferer matched with a 28mm-diameter artificial thigh bone, the wear-resisting of a 6-8mm artificially acetabulum is better, when the inner spherical radius is a little bigger than artificially acetabulum. Also, except the high –usage of stuff, it can prove the best balance performance and provide theoretical foundation to the optimum design of artificial acetabulum.

Abstract: A completely interconnected macroporous and microporous poly(l-lactic acid) (PLLA) scaffold was fabricated from a PLLA–dioxane–water ternary system by an advanced manufacturing technology called low-temperature deposition manufacturing. A proper fraction of water and PEG added into the polymer solution induces liquid-liquid phase separation and gelation. The liquid-liquid phase separation brings in a new micro morphology and gelation effect produces higher fabrication accuracy.

Abstract: The average Reynolds equation and average clearance equation of circular translational polishing (CTP) under the quasi-stable mixed lubrication state are set up in polar coordinates. The distributions of fluid pressure and contact pressure during polishing are numerically analyzed by solving simultaneously these equations along with the contact pressure equation. The effects of various process parameters on hydrodynamic performance of CTP are analyzed. By comparing the distributions of periodic average pressure along radial direction under fully and partially lubricated states, we conclude that carefully controlled CTP under mixed lubrication is beneficial to improving the surface quality and planarity of the wafer.