ORCID Profile
0000-0002-5064-0917
Current Organisation
University of Auckland Faculty of Engineering
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Publisher: IOP Publishing
Date: 18-06-2001
Publisher: AIP
Date: 2010
DOI: 10.1063/1.3463182
Publisher: American Chemical Society (ACS)
Date: 14-08-2013
DOI: 10.1021/CG400835N
Publisher: Wiley
Date: 28-02-2017
Publisher: Wiley
Date: 06-03-2017
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3CE41184B
Publisher: IOP Publishing
Date: 25-09-2001
Publisher: American Chemical Society (ACS)
Date: 07-11-2002
DOI: 10.1021/JP026814E
Publisher: Elsevier BV
Date: 11-2008
Publisher: Springer Science and Business Media LLC
Date: 17-03-2015
DOI: 10.1038/SREP09159
Abstract: X-ray diffraction technique using a laboratory radiation has generally shown limitation in detectability. In this work, we investigated the in situ high-temperature crystallization of a lithium disilicate glass-ceramic in the SiO 2 –Li 2 O–CaO–P 2 O 5 –ZrO 2 system with the aid of synchrotron radiation. The formation of lithium metasilicate and other intermediate phases in trace amount was successfully observed by synchrotron X-ray diffraction (SXRD). The crystallization mechanism in this glass was thus intrinsically revised to be the co-nucleation of lithium metasilicate and disilicate, instead of the nucleation of lithium disilicate only. The phase content, crystallite size and crystallographic evolutions of Li 2 Si 2 O 5 in the glass-ceramic as a function of annealing temperature were studied by performing Rietveld refinements. It is found that the growth of Li 2 Si 2 O 5 is constrained by Li 2 SiO 3 phase at 580–700°C. The relationship between the crystallographic evolution and phase transition was discussed, suggesting a common phenomenon of structural response of Li 2 Si 2 O 5 along its c axis to other silicon-related phases during glass crystallization.
Publisher: IOP Publishing
Date: 10-1998
Publisher: World Scientific Pub Co Pte Lt
Date: 30-06-2010
DOI: 10.1142/S0217979210064745
Abstract: In this study, constitutional liquation in AZ91 cast alloy at 440°C and 465°C was experimentally simulated. Metallurgical examination was conducted to reveal the morphology of the constitutional liquid and dihedral angle was measured to evaluate the wettability of the liquid on grain boundary. Dihedral angle was found to be initially ~30 degree and thus grain boundaries were incomplete wet. During annealing, the metastable constitutional liquid resolidified, followed by grain growth. The extent of grain boundary wetting by the remaining liquid increased slightly with treating time. The rate of resolidification was also evaluated and the factors affecting this rate were discussed.
Publisher: Elsevier BV
Date: 12-2003
Publisher: Springer Science and Business Media LLC
Date: 24-07-2013
Publisher: Elsevier BV
Date: 02-2003
Publisher: Elsevier BV
Date: 05-2014
Publisher: American Chemical Society (ACS)
Date: 22-11-2013
DOI: 10.1021/IC402112Z
Abstract: In this work, the high-temperature crystallographic evolution of crystalline phases in a complex lithium disilicate glass was investigated using synchrotron X-ray powder diffraction. The lattice parameters and unit cell volume of Li2SiO3 (LS), Li2Si2O5 (LS2), Li3PO4 (LP), and ZrO2 as a function of temperature were determined upon heating. It is found that the lattice parameter c of LS2 shows a "V"-shaped trend during heating. The crystallographic evolution of the LS2 phase has a close correlation with the LS phase, indicating the mutual interaction between LS and LS2 phases along the c axis during the nucleation/crystallization process. The phase evolution processes were different upon heating and cooling, and the unit cell volume of both LS and LP phases demonstrated different change rates. In this glass system, no LS2 was detected during cooling and the main phases formed during cooling process were LP, LS, β-cristobalite, and β-quartz. Interestingly, there were two forms of β-quartz with slightly different lattice constants, and the silica phases showed a near-zero expansion behavior. The crystallographic evolution mechanism is discussed.
Publisher: World Scientific Pub Co Pte Ltd
Date: 06-2015
DOI: 10.1142/S1793604715400111
Abstract: In this paper, we report a series of homogeneous polymeric composites with enhanced dielectric properties and thermal conductivity. The composites were constituted of polyvinylidene fluorides (PVDFs) matrix and CaCu 3 Ti 4 O 12 (CCTO) monolithic or CCTO/β- SiC hybrid fillers, and prepared by simple melt blending and hot moulding technique. The influence of different types of fillers and their composition on the dielectric response and thermal conductivity of the obtained composites was studied. Results show that hybrid loading is preferred and a reasonable combination of thermal conductivity (0.80 W⋅m -1 ⋅K -1 ), dielectric constant (∼50) and dielectric loss (∼0.07) at 10 3 Hz was achieved in the PVDF composite containing 40 vol.% CCTO and 10 vol.% β- SiC . The strong dipolar and interfacial polarization derived from the fillers are responsible for the enhancement of the dielectric constant, while the formation of thermally conductive networks/chains by β- SiC whiskers contributes to the improved thermal conductivity.
Publisher: IOP Publishing
Date: 10-1998
Publisher: World Scientific Pub Co Pte Lt
Date: 25-07-2013
DOI: 10.1142/S0217984913410121
Abstract: In this paper, Nitinol, an equiatomic binary alloy of nickel and titanium, was surface modified for its potential biomedical applications by chemical and electrochemical etching. The main objective of the surface modification is to reduce the nickel content on the surface of Nitinol and simultaneously to a rough surface microstructure. As a result, better biocompatibility and better cell attachment would be achieved. The effect of the etching parameters was investigated, using scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectrometry (EDX) and X-ray photoelectron spectrometry (XPS). The corrosion property of modified Nitinol surfaces was investigated by electrochemical work station. After etching, the Ni content in the surface layer has been reduced and the oxidation of Ti has been enhanced.
Publisher: Wiley
Date: 06-03-2017
Publisher: Elsevier BV
Date: 03-2014
Publisher: American Chemical Society (ACS)
Date: 28-08-2014
DOI: 10.1021/CG500841X
Publisher: Springer Science and Business Media LLC
Date: 30-09-2009
Publisher: Elsevier BV
Date: 2006
Publisher: Elsevier BV
Date: 04-2023
Publisher: The Electrochemical Society
Date: 2014
DOI: 10.1149/2.032406JES
Publisher: Wiley
Date: 28-02-2017
Abstract: Aluminum-nitrogen six-fold octahedral coordination, [AlN
Publisher: World Scientific Pub Co Pte Lt
Date: 23-04-2015
DOI: 10.1142/S0217979215400032
Abstract: CaCu 3 Ti 4 O 12 (CCTO)–poly(vinylidene fluoride (PVDF)) composites were prepared by melt blending and hot molding techniques. The addition of CCTO remarkably enhanced the dielectric properties and the thermal conductivity of PVDF composites, while the melting point of the PVDF composites (~170°C) was almost independent of the CCTO concentration. Based on the results of dielectric constant and dielectric breakdown voltage, the PVDF composite containing 40 vol.% CCTO fillers shows the optimized capacitive energy storage potential (7.81 J/cm 3 ).
Publisher: AIP Publishing
Date: 11-2001
DOI: 10.1063/1.1406551
Abstract: Heat-flow changes of La1−xCaxMnO3+δ (x=0.25, 0.33, and 0.375) magnetoresistive oxides at their Curie temperatures have been detected using differential scanning calorimetry in the temperature range from 173 to 293 K. However, the transition does not occur in the s les of x=0.125 and 0.5. It was found that the heat flow reflected the transition behavior and the enthalpy change of the transition decreased as the transition temperature increased. These results indicate that the La1−xCaxMnO3+δ oxides (x=0.25, 0.33, and 0.375) undergo an endothermic phase transition from a low-temperature ferromagnetic metal to a high-temperature paramagnetic insulator. It is assumed that the transition is strongly associated with a local structure change, which is correlated with the metal–insulator transition.
Publisher: Elsevier BV
Date: 04-2015
DOI: 10.1016/J.SCITOTENV.2015.01.068
Abstract: In this study, we pyrolysed six waste derived biomass: pine sawdust (PSD), paunch grass (PG), broiler litter (BL), sewage sludge (SS), dewatered pond sludge (DWP), and dissolved air-floatation sludge (DAF) into biochar. Biochars were characterized using scanning electron microscopy, energy dispersive X-ray spectrometry, X-ray diffraction, Fourier transform infrared spectroscopy, inductively-coupled plasma mass spectrometry, (13)C-solid-state nuclear magnetic resonance spectroscopy, and X-ray photoelectron spectroscopy to evaluate their feasibility for potential agronomic and environmental applications. Syngas produced during the pyrolysis process was also analyzed to determine the energy values. Results show that PSD biochar has the utmost potential for carbon sequestration and contaminant remediation due to its high surface area, aromaticity and carbon content. Additionally given its low ash content, PSD biochar could also potentially be used as filler in wood plastic biocomposites. Low levels of heavy metals (Cr, Cu, Zn, As, Cd, Hg, and Pb) in all biochars suggest that biochars are also applicable for land application according to the United States Environmental Protection Agency regulation 40 CFR part 503. The composition of syngas evolved during the pyrolysis of feedstocks showed little difference in the calorific values, ranging from 12-16 MJ/dsm with PSD having the maximum calorific value of 16 MJ/dsm.
Publisher: Elsevier BV
Date: 07-2010
Publisher: IOP Publishing
Date: 10-01-2002
Publisher: IOP Publishing
Date: 11-07-2001
Publisher: Elsevier BV
Date: 12-2012
Publisher: Elsevier BV
Date: 09-2001
Publisher: Elsevier BV
Date: 08-2014
Publisher: Elsevier BV
Date: 07-2001
Publisher: Springer Science and Business Media LLC
Date: 06-03-2015
Publisher: American Vacuum Society
Date: 03-2001
DOI: 10.1116/1.1347048
Abstract: The Ti layer deposited by ionized metal plasma deposition technique and the reacted region between Ti and Al–0.5%Cu, in Al–0.5%Cu/Ti/SiO2/Si structure, were characterized by scanning transmission electron microscopy (STEM) and Rutherford backscattering spectroscopy (RBS). The results indicate that the Ti layer with a column-like structure grew epitaxially in the close-packed [001] direction. This growth mechanism resulted in a high-density Ti layer in Al–0.5%Cu/Ti/SiO2/Si structure. This epitaxially grown Ti layer has anisotropic diffusion properties that can retard the diffusion of Al across the Ti layer in the initial stage of high temperature Al sputtering or reflow processes. But the column-like Ti crystals recrystallized during further processing, altered the [001] alignment of the crystals to cause the interdiffusion of Ti and Al. The reactions between Ti and Al took place subsequently and formed the intemetallic Al3Ti, Al5Ti2, TiAl, and Ti3Al layers from the surface inwards. As the diffusion of Al in Ti, Ti3Al, and TiAl decreased in order, the formation of Ti3Al and TiAl layers further retarded the diffusion of Al into the SiO2 layer. It can be concluded that the intermetallic layers play an important role of diffusion barrier that impede the migration of Al across the films.
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Wei Gao.