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 & Turbulence. The organization has 10766 authors who have published 19140 publications receiving 255696 citations. The organization is also known as: Nagoya Kōgyō Daigaku & Nitech.

Tuning the selectivity of NH 3 gas sensing response using Cu-doped ZnO nanostructures

Abstract: Copper-doped ZnO (CZO) nanoflower and nanoellipsoids were synthesized by hydrothermal method. Field emission electron microscopy and transmission electron microscopy revealed that the flower-like morphology of undoped ZnO transformed into nanoellipsoids upon incorporation of copper (Cu) in ZnO. Raman spectra of copper- doped ZnO showed E2L peak shift compared with undoped ZnO nanoflower which indicated enhanced oxygen or zinc vacancy in copper-doped ZnO. Low-temperature ammonia gas sensing properties based on copper-doped ZnO were systematically studied. Cu-doped ZnO (6 wt%) showed enhanced selectivity compared with other copper doping (wt%). Furthermore, the Cu-doped ZnO showed an excellent response and recovery time at a low concentration of ammonia (10 ppm). Cu-doped ZnO showed better long-term stability and reproducibility towards ammonia gas.

Growth behavior of compound layers during reactive diffusion between solid Cu and liquid Al

Abstract: In order to examine experimentally the kinetics of the reactive diffusion between solid Cu and liquid Al, Cu/Al diffusion couples were isothermally annealed in the temperature range between T = 973 and 1073 K. Owing to annealing, compound layers consisting of the β, γ1 and ɛ2 phases are produced between the Cu-rich solid (α) and Al-rich liquid (L) phases. The β, γ1 and ɛ2 phases are the only stable compounds at T = 973–1073 K. The mean thickness of each compound layer is proportional to a power function of the annealing time. For the β layer, the exponent of the power function is close to 0.5 at T = 1023–1073 K, but nearly equal to 0.25 at T = 973 K. On the other hand, for the γ1 layer, the exponent takes values between 0.25 and 0.5 at T = 1023–1073 K, but that smaller than 0.25 at T = 973 K. The exponent smaller than 0.5 indicates that grain boundary diffusion predominantly controls the growth of the compound layer and grain growth occurs at a certain rate. In contrast, the ɛ2/L interface migrates towards the α phase. The migration distance of the ɛ2/L interface is much greater than the total thickness of the compound layers, and proportional to the square root of the annealing time. Consequently, the migration of the ɛ2/L interface is governed by interdiffusion in the L phase. According to estimation, the interdiffusion coefficient is much greater for the L phase than for the solid phases. As a result, the ɛ2/L interface migrates towards the α phase, and the migration rate of the interface is much greater than the overall growth rate of the compound layers.

Direct Asymmetric Mannich‐Type Reaction of α‐Isocyanoacetates with Ketimines using Cinchona Alkaloid/Copper(II) Catalysts

Abstract: The enantioselective direct Mannich-type reaction of ketimines with α-isocyanoacetates has been developed. Excellent yields and enantioselectivity were observed for the reaction of various ketimines and α-isocyanoacetates using cinchona alkaloid/Cu(OTf)2 and a base. Both enantiomers of the products could be obtained by using pseudoenantiomeric chiral catalysts. This process offers an efficient route for the synthesis of α,β-diamino acids.