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.

Normally-OFF Al2O3/AlGaN/GaN MOS-HEMT on 8 in. Si with Low Leakage Current and High Breakdown Voltage (825 V)

Abstract: We report recessed-gate Al2O3/AlGaN/GaN normally-OFF metal–oxide–semiconductor high-electron-mobility transistors (MOS-HEMTs) on 8 in. Si. The MOS-HEMTs showed a maximum drain current of 300 mA/mm with a high threshold voltage of +2.4 V. The quite low subthreshold leakage current (~10−8 mA/mm) yielded an excellent ON/OFF current ratio (9 × 108) with a small, stable subthreshold slope of 74 mV/dec. An atomic-layer-deposited Al2O3 layer effectively passivates, as no significant drain current dispersions were observed. A high OFF-state breakdown voltage of 825 V was achieved for a device with a gate-to-drain distance of 20 µm at a gate bias of 0 V.

Bioactive silica–poly(γ-glutamic acid) hybrids for bone regeneration: effect of covalent coupling on dissolution and mechanical properties and fabrication of porous scaffolds

Abstract: It is well known that bone has excellent mechanical properties through its hierarchical structure and that design of new materials should take inspiration from its structure, especially those that will be used as synthetic bone grafts. However it has not yet been possible to mimic the complex structure. Here we present new organic–inorganic hybrid scaffolds produced by a sol–gel foaming process with the aim of producing materials that mimic the trabecular structure of bone and take inspiration from the nanocomposite structure. Poly(γ-glutamic acid) (γ-PGA) was chosen as the organic component because it is a polypeptide that can be functionalised and can degrade by enzyme action. The γ-PGA chains and bioactive silica were covalently bonded to each other (class II hybrid) through an organosilane coupling agent, glycidoxypropyl trimethoxysilane (GPTMS). This was key to obtaining a hybrid with good mechanical properties and homogeneous integration of inorganic and organic chains at the nanoscale. The effect of the degree of covalent coupling on mechanical properties and dissolution rate of the hybrids was investigated. Hybrids with a covalent coupling between 2 and 10 glutamic acid units per GPTMS molecule showed optimal mechanical properties and polymer release into TRIS-buffer solution. Polymer release was much slower from these hybrids than from those with lower amounts of covalent coupling. Monoliths of these compositions were not toxic to the SaOs-2 osteosarcoma cell line and supported cell attachment and growth. Foaming of the optimised hybrid composition was performed to produce porous 3D scaffolds. The modal pore and interconnect diameters were quantified to be 297 and 111 μm respectively, using micro-computed tomography (μCT) and image analysis, showing the pore network to mimic that of cancellous bone.

Environmental Burden Analysis for Machining Operation Using LCA Method

Abstract: We have developed an environmental burden analyzer for machine tool operations, which can evaluate an NC program from the view point of an environment burden by simulating a cutting process and using emission intensities. In this paper, global warming is selected as an impact category and the environmental burden analysis of dry, wet and MQL machining operations are carried out by using this analyzer with consideration of various situations. The influence of the peripheral devices of a machine tool, the spindle and the servo motors, the coolant, the lubricant oil, the cutting tool and the metal chips to global warming is introduced in detail.

Diffuse reflectance infrared Fourier transform spectral study of the interaction of 3-aminopropyltriethoxysilane on silica gel. Behavior of amino groups on the surface

Abstract: Three silica gel sample systems, modified with 3-aminopropyltriethoxysilane (APTS), were prepared by sequentially sampling the reaction mixture at various time intervals, and the diffuse reflectance infrared Fourier transform (DRIFT) spectra of these samples were measured in the regions 2700–3500 and 1300–2000 cm-1. The IR bands observed at 1597 and 1629–1633 cm-1 were assigned to the deformation modes of NH2 and NH 3 + groups, respectively. The intensities of these two bands are dependent on both the APTS concentration used in the preparation and the reaction time. The results are summarized as follows. For the sample systems in which smaller APTS concentration were used, most of the NH2 groups of the aminopropyl segments are converted into the NH 3 + groups on the surface, showing that the SiO- H+ NH2- type structure is predominantly stabilized on the surface of the silica gel. As the APTS concentration in the reaction mixture increases, the population of NH2 groups in the silane layer coated onto the surface increases. Interpretation of the CH stretch region further suggests that cyclic structures may be formed on the surface as a consequence of the formation of NH 3 + groups.