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Project based teaching has already been used in many countries around the world, including Vietnam. After overview research about project based teaching of some domestic and foreign authors, we suggest that the process of organizing project based teaching in the training of math teachers in Vietnam include 4 stages: Preparation; Planning the way to perform teaching projects; Performance of the project; Reporting the products and assessing the projects. In the final part of the article, we will mention the use of this form of teaching in the process of showing the methods of teaching to students of Math Education in Vietnam. The results of this experiment have shown the effectiveness of this form of teaching in the training of math teachers in pedagogical universities in Vietnam. [ABSTRACT FROM AUTHOR]

Temperature-dependent photoluminescence (PL) of graphene oxide (GO) reduced with hydrazine and heat has been measured to investigate the effect of reduction type on the bandgap of the reduced GO. Nitrogen functionalities formed in the hydrazine-treated GO were responsible for a strong localization of carriers that caused in a fluctuation in PL peak position with temperature. The intensity of C-OH peak was relatively low in the heat-treated GO, indicating that raising temperature facilitated the removal of hydroxyl groups, resulting in larger sp2 domain size and smaller bandgap energy. [ABSTRACT FROM AUTHOR]

Chemically converted graphene that was reduced with phenylhydrazine was highly dispersed in organic solvents, and its “paper” prepared by filtration of the reduced graphene possessed an electrical conductivity value as high as 20 950 S m−1. [ABSTRACT FROM AUTHOR]

The Fe1-xGax thin films (x = 0.4, 0.5) have been grown on GaSb(100) substrate using molecular beam epitaxy. An epitaxial film with bcc a-Fe crystal structure (A2) is observed in Fe0.6Ga0.4 film, while an impure Fe3Ga phase with DO3 structure is appeared in Fe0.5Ga0.5 film. The saturated magnetizations at room temperature are observed to be 570 emu/cm3 and 180emu/cm3 and the coercivities to be 170 and 364Oe for Fe0.6Ga0.4 and Fe0.5Ga0.5, respectively. A hysteresis trend in Hall resistance vs. magnetic field is observed for Fe0.5Ga0.5 film. However, there is a weak hysteresis noticed in Fe0.4Ga0.6 thin film. [ABSTRACT FROM AUTHOR]

[Display omitted] • Introduction of spinel-layered Li 3 MnTiO 4+ z cathode materials. • Heterostructure of the cathode material enables facile Li+ transport. • Activation of the layered phase increases voltage and capacity of the cathode. Herein, a layered-spinel structure of Li 3 MnTiO 4+ z (0.8Li 2 Mn 0.5 Ti 0.5 O 3 •0.2LiMnTiO 4) as a working electrode (WE) for Li-ion batteries was synthesized successfully by a solid-state reaction. The cathode delivers a capacity of 80 mAh g−1 for the first discharge. During a working cycle of the battery, the layered-phase material was activated, which contributes to the voltage increase in the 3 V region. The layered phase activation also contributes to the rise in cathode capacity and after 24 cycles, it could reach a capacity of 190 mAh g−1. Moreover, numerous Ti atoms substituted for Mn, and the composite structure facilitated the fast Li+ diffusion, leading to the Li+ diffusion coefficient number in the cathode showing a high value of 3.28 × 10−10 cm2 s−1. [ABSTRACT FROM AUTHOR]

We report a device that combines indium tin oxide (ITO) nanodot nodes with two-dimensional chemically converted graphene (CCG) films to yield a GaN-based light emitting diode (LED) with interesting characteristics for transparent and current spreading electrodes for the potential use in the ultraviolet region. The current-voltage characteristics and electroluminescence output power performance showed that CCG network on ITO nanodot nodes operated as a transparent and current spreading electrode in LED devices. [ABSTRACT FROM AUTHOR]

This article reports on the development of a reduced graphene oxide (rGO)-embedded light-emitting diode (LED) on a patterned sapphire substrate (PSS), for improving heat dissipation and reducing threading dislocations. The prototype device fabrication involves the generation of scalable curved graphene oxide microscale patterns on a PSS, followed by thermal reduction and epitaxial lateral overgrowth of GaN in a metal–organic chemical vapor deposition system with a one-step process. Using the forward voltage method, the junction temperature Tj of the rGO-embedded LED was found to be reduced by about 17 °C from the ∼62 °C of the LED grown without the rGO buffer layer. Temperature-dependent light output power and chip surface temperature measurements were also performed and the results are discussed. [ABSTRACT FROM AUTHOR]