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Nha Trang, Vietnam

Nha Trang University is a university in Nha Trang, Khánh Hòa Province, in Vietnam's South Central Coast. This a multidisciplinary university with 29 specialities from vocational training to doctor's degree. Wikipedia.


Tra T.H.,Nha Trang University | Okazaki M.,Nagaoka University of Technology | Suzuki K.,Niigata University
International Journal of Fatigue | Year: 2012

Behavior of fatigue crack which was propagated at some representative areas in the friction stir welded (FSWed) joint of aluminum alloy 6063-T5 was studied. By extracting the T-L orientation specimens so that the loading axis on the fatigue test and the crack propagation direction were transverse and longitudinal to the welding direction, respectively, the crack propagation tests were carried out for both the as-welded and post-weld heat treated (PWHTed) FSWs at room temperature and 200°C. The experiments showed that the fatigue crack propagation (FCP) rates were sensitive to the propagating location, the test temperature, and the PWHT condition as well. It was also found that the different FCP rates were driven by the microstructural influences in and around the welded zone. While the residual stress was remarkable in the shoulder limit areas, it had a minor effect on the FCP behavior. © 2012 Elsevier Ltd. All rights reserved. Source


Nguyen V.H.,Yeungnam University | Nguyen V.H.,Nha Trang University | Shim J.-J.,Yeungnam University
Journal of Power Sources | Year: 2015

A facile and efficient two-step method for the decoration of graphene sheets and nickel cobalt oxide (NiCo2O4) nanoparticles on conducting nickel foam was developed. First, graphene and a bimetallic (Ni, Co) hydroxide precursor were deposited on a Ni foam support by electrodeposition followed by a thermal transformation of the bimetallic hydroxide to NiCo2O4. The graphene layer with a thickness of a few nanometers was decorated with NiCo2O4 nanoparticles, ranging in size from 3 to 5 nm. The nickel foam electrode supported graphene and NiCo2O4 exhibited rapid electron and ion transport, large electroactive surface area, and excellent structural stability. The specific capacitance of the obtained electrode was as high as 1950 F g-1 at a high current density of 7.5 A g-1, suggesting its promising applications as an efficient electrode for electrochemical capacitors. © 2014 Elsevier B.V. All rights reserved. Source


Nguyen V.H.,Yeungnam University | Nguyen V.H.,Nha Trang University | Shim J.-J.,Yeungnam University
Electrochimica Acta | Year: 2015

Hierarchical mesoporous NiCo2S4@MnO2 core-shell structured arrays on nickel foam were designed and fabricated using a facile hydrothermal method for supercapacitor applications. The electrodes exhibited rapid electron and ion transport, large electroactive surface area, and excellent structural stability owing to the highly conducting nature of the well-defined mesoporous NiCo2S4 nanowire arrays in combination with the large surface area provided by the ultrathin MnO2 nanosheets and ultralong MnO2 nanowires, as well as to the open framework of the three-dimensional nanoarchitectures. The specific capacitance of the resulting electrode was as high as 17.5 F cm-2 at a very high current density of 100 mA cm-2, highlighting its potential as an efficient electrode for electrochemical capacitors. © 2015 Elsevier Ltd. All rights reserved. Source


Nguyen V.H.,Yeungnam University | Nguyen V.H.,Nha Trang University | Shim J.-J.,Yeungnam University
Materials Science and Engineering B: Solid-State Materials for Advanced Technology | Year: 2014

A graphene-TiO2 hybrid was synthesized by a solvothermal microwave-assisted method in a mixture of two green solvents: water and an ionic liquid (1-butyl-3-methylimidazolium tetrafluoroborate, [bmim][BF4]). Graphene oxide (GO) could be easily reduced under microwave irradiation without any additional reducing reagent. Titanium (IV) isopropoxide was used as a starting material for the growth of TiO2 nanoparticles on the graphene sheets accompanied by the reduction of GO. The structure and morphology of the as-prepared hybrid were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and thermogravimetric analysis. The graphene-TiO2 hybrid had a high surface area and exhibited high photocatalytic degradation of methylene blue. © 2013 Elsevier B.V. All rights reserved. Source


Hoa Nguyen V.,Yeungnam University | Hoa Nguyen V.,Nha Trang University | Shim J.-J.,Yeungnam University
Materials Letters | Year: 2015

Nickel foam was decorated with graphene and cobalt oxide (Co3O4) sheets by chemical vapor deposition and electrochemical deposition, respectively. After coated by a thin graphene layer, the nickel foam was decorated with Co3O4 nanoparticles, ranging in size from 3 to 5 nm. The resulted electrode allowed the rapid transportation of electrons and ions with a large electroactive surface area, and showed excellent structural stability. The specific capacitance of the electrode was as high as 1126 F g-1 at a high current density of 7.5 A g-1 in KOH 3 M electrolyte, highlighting its promising applications as a high performance electrode for supercapacitors. © 2014 Elsevier B.V. All rights reserved. Source

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