Nagoya Institute of Technology

About: Nagoya Institute of Technology is a education organization based out in Nagoya, Japan. It is known for research contribution in the topics: Thin film & Catalysis. The organization has 10766 authors who have published 19140 publications receiving 255696 citations. The organization is also known as: Nagoya Kōgyō Daigaku & Nitech.

Grain refining performance for Al and Al–Si alloy casts by addition of equal-channel angular pressed Al–5 mass% Ti alloy

Abstract: This paper investigated the microstructural evolution and the grain refining performance of an Al–5 mass% Ti alloy that was fabricated by the equal-channel angular pressing (ECAP) method. The microstructures were observed by a scanning electron microscopy (SEM). Platelet-shaped Al3Ti particles cracked severely with repetitive ECAP passes, and the mean size of the Al3Ti particles decreased from 70 to 3.2 μm after 15 ECAP passes. Energy dispersive X-ray spectroscopy (EDXS) and X-ray diffraction (XRD) analysis showed an Al–Ti supersaturated solid solution was formed during the ECAP process. Moreover, when the ECAPed Al–Ti alloy with the Al–Ti supersaturated solid solution was added to pure Al and Al–Si eutectic alloy melts, a better grain refining effect was obtained compared to that of the same alloy without the ECAP. It is considered that the fine Al3Ti particles and the Al3Ti precipitates from the supersaturated solid solution probably contribute to the grain refinement. The pure Al and Al–12.6 mass% Si alloy that was refined by the ECAPed Al–5 mass% Ti refiner had a high Vickers microhardness and good wear resistance. It is suggested that the ECAPed Al–5 mass% Ti alloy could become an effective refiner in commercial Al cast production.

Cross-sectional TEM observation of copper-implanted SiO2 glass

Abstract: Transmission electron microscopic observation has been made on SiO2 glass implanted to a dose of 6 × 1016 ions/cm2 at an energy of 160 keV and in a sample implanted to 6 × 1016 ions/cm2 at 169 keV and to 2 × 1016 ions/cm2 at 35 keV. In the sample with 6 × 1016 ions/cm2, the depth distribution of implanted Cu is bimodal in shape. It has been found that nano-sized particles of copper are formed in both depth regions of the bimodal distribution and the distribution of Cu colloid diameters has a shape that is close to that of implanted Cu concentrations. A triple layer of Cu colloid particles has been formed by sequential implantation using differing acceleration voltages (160 keV followed by 35 keV).

Silicon nanowire array/polymer hybrid solar cell incorporating carbon nanotubes

Abstract: Here we present a simple and novel approach of fabricating three dimensional (3D) n-Si nanowires (NWs) and poly(3-octylthiophene) hybrid solar cells incorporating carbon nanotubes (CNTs). Vertically aligned n-Si NWs arrays were fabricated by electroless chemical etching of a n-Si [1?1?1] wafer. n-Si NWs/poly(3-octylthiophene) hybrid solar cells were fabricated with and without functionalized CNTs incorporation. Fabricated solar cells incorporating CNTs show open circuit voltage (Voc), short circuit current density (Jsc) fill factor (FF) and conversion efficiency as 0.353, 7.85?mA?cm?2, 22% and 0.61%, respectively. In fabricated devices n-Si NWs arrays form multiple heterojunctions with the polymer and provide efficient electron collection and transportation, whereas CNTs provide efficient hole transportation.

Microwave dielectric properties of forsterite-based solid solutions

Abstract: Recently forsterite has been reported as an excellent dielectric material for millimeter wave application. However, its temperature variation of the resonant frequency ( τ f ) is relatively large which precludes its immediate use in practical applications. In this paper, we report the effect of substituting Ca and Mn for Mg on the microwave dielectric properties of forsterite. The composition 0.975Mg 2 SiO 4 –0.025Mn 2 SiO 4 showed excellent Q × f value of 180,000 GHz with a τ f of −71 ppm/°C. The end member Mn 2 SiO 4 , showed a Q × f of 50,000GHz, ɛ r of 8.52 and τ f = −90 ppm/°C. In the case of Ca substitution for Mg, τ f shifted to high negative value with increasing amount of Ca. However, Q × f did not show much change in its value. It is suggested that the increase of τ f towards a more negative value is related to the ionic radii of the substitutes.