Qian Wang 교수

<p>\n\tFirst-row transition metal-containing ionic liquids (ILs) were synthesized and used to catalyze the degradation of poly(ethylene terephthalate) (PET) in ethylene glycol (EG). One important feature of these IL catalysts is that they have good thermal stability, and most of them, especially [bmim](2)[CoCl4] (bmim = 1-butyl-3-methyl-imidazolium) and [bmim](2)[ZnCl4], exhibit higher catalytic activity, compared with traditional catalysts, conventional IL catalysts, and some functional I

Metal salts and solid super acids are the common catalysts used in the glycolysis of poly(ethylene terephthalate)(PET) wastes to obtain monomer bis(hydroxyethyl) terephthalate (BHET) with high conversion of PET and selectivity of BHET, but there are some drawbacks, such as severe reaction conditions, slow reaction rates and difficult recycling of the catalyst. In this study, urea, as a green, highly active, low-priced, extensive and easily produced catalyst, has been used for the degradation of

Investigation of the mixed lubrication of journal-bearing conformal contacts is very important for failure prevention and design improvement. This paper studies the asperity contact in heavily loaded journal bearings with Lee and Ren’s asperity contact theory in a newly developed mixed-TEHD (Thermal Elasto-Hydro-Dynamic) model and analyzes the performance of simulated journal bearings under high eccentricity ratios. The effects of operating conditions, bearing structures, and thermal conditions

Numerical analyses of finite journal bearings operating with large eccentricity ratios were conducted to better understand the mixed lubrication phenomena in conformal contacts. The average Reynolds equation derived by Patir and Cheng was utilized in the lubrication analysis. The influence function, calculated numerically using the finite element method, was employed to compute the bearing deformation. The effects of bearing surface roughness were incorporated in the present analysis for the cal

Today, a growing number of third-generation semiconductor-based power devices are used in products that can continuously operate at high temperatures for extended periods of time. Hence, traditional tin-lead and lead-free solders are no longer suitable for modern electronic packaging. A common method is to apply Ag paste for bare Cu–Cu joints under an inert or reductive atmosphere. In this study, the citrate-coated nanosized Ag paste was utilized to generate robust bare Cu–Cu joints under atmosp

It is of great importance to thoroughly understand residual stress distribution in wire arc additive manufacturing (WAAM) and its relationship with the deposition variables. In this study, stainless steels 308LSi and 304 were used as WAAM feedstock and substrate, respectively, for additive manufacturing of two typical structures, namely wall and pipe structures. A thermomechanical coupling analysis model for WAAM was developed to investigate the formation mechanism of residual stresses in both s

<p>\n\tThe electrodeposition of aluminum (Al) on copper (Cu) substrate was investigated in [Bmim] Cl/AlCl3 (33.3/66.7 mol%) ionic liquid using three pyridine derivatives, nicotinic acid, methyl nicotinate, and 3-methyl pyridine as additives at 303 K, respectively. It was found that bright Al coatings could be electrodeposited with nicotinic acid and methyl nicotinate as additives. SEM and XRD characterizations revealed that the bright coatings were very smooth, composed of nanocrystalline

In this paper, Ni-based alloy coating was prepared on pure iron substrate by steady magnetic field assisted laser cladding technology. The influence mechanism of steady magnetic field on the Ni-based coating was investigated by analyzing the macro-morphology, phase composition, microstructure, element composition and properties of the coatings, respectively. The results reveal that external magnetic field can restrain the surface fluctuation of the coatings. It has no effect on the phase composi

Fusion-based additive manufacturing techniques such as selective laser melting, electron beam freeform fabrication cause solidification problems such as grain coarseness and high porosity. As a new technique, cold spraying (CS) can overcome such melting-induced drawbacks. In this study, a material model using dislocation dynamics was developed specifically for the CS process for describing the following five nanosecond-scale physical phenomena: strain hardening, normal-range strain rate hardenin