다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

Wide bandgap semiconductors show superior material properties enabling potential power device operation at higher temperatures, voltages, and switching speeds than current Si technology. As a result, a new generation of power devices is being developed for power converter applications in which traditional Si power devices show limited operation. The use of these new power semiconductor devices will allow both an important improvement in the performance of existing power converters and the development of new power converters, accounting for an increase in the efficiency of the electric energy transformations and a more rational use of the electric energy. At present, SiC and GaN are the more promising semiconductor materials for these new power devices as a consequence of their outstanding properties, commercial availability of starting material, and maturity of their technological processes. This paper presents a review of recent progresses in the development of SiC- and GaN-based power semiconductor devices together with an overall view of the state of the art of this new device generation.

A Survey of Wide Bandgap Power Semiconductor Devices

Light-Emitting Diodes. (Monographs in Electrical and Electronic Engineering.) By A. A. Bergh and P. J. Dean. Pp. viii+591. (Clarendon: Oxford; Oxford University: London, 1976.) £22.

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Light-emitting diodes

An object is to provide a semiconductor device of which a manufacturing process is not complicated and by which cost can be suppressed, by forming a thin film transistor using an oxide semiconductor film typified by zinc oxide, and a manufacturing method thereof. For the semiconductor device, a gate electrode is formed over a substrate; a gate insulating film is formed covering the gate electrode; an oxide semiconductor film is formed over the gate insulating film; and a first conductive film and a second conductive film are formed over the oxide semiconductor film. The oxide semiconductor film has at least a crystallized region in a channel region.

Semiconductor device, and manufacturing method thereof

We investigate an impact of annealing temperature on surface passivation of SiC epitaxial layers with deposited SiO 2 followed by POCl 3 annealing. The POCl 3 annealing process consists of two steps: (i) thermal annealing in POCl 3 and (ii) subsequent thermal annealing in pure N 2 . We find that the annealing temperature of the subsequent N 2 annealing is important to reduce surface recombination on SiC. For surface passivation, N 2 annealing at high temperature at 1000° C is necessary.

Impact of annealing temperature on surface passivation of SiC epitaxial layers with deposited SiO 2 followed by POCl 3 annealing

PROBLEM TO BE SOLVED: To provide a manufacturing method of an SiC semiconductor element which prevents an electrode metal from diffusing in an SiC single crystal substrate and forms an ohmic electrode.SOLUTION: In a manufacturing method of an SiC semiconductor element including a process where an ohmic electrode is formed on an SiC substrate, a gettering layer, having higher defect density than the SiC substrate, is formed on the SiC substrate so as to be arranged parallel with a surface of the SiC substrate. Then, the ohmic electrode is formed at the outer side of the substrate relative to the gettering layer.

MANUFACTURING METHOD OF SiC SEMICONDUCTOR ELEMENT

The band structures of Sn nanowires with various cross-sectional shapes and orientations were calculated by a tight-binding method. The wave functions of bulk Sn and Sn nanowires were also analyzed. The calculation revealed that the conduction band minimum of some Sn nanowires originates from the electronic states in the valence band of bulk Sn. This behavior was discussed in terms of the dependence on the orientation and cross-sectional shape of Sn nanowires. In addition, we clarified that the [110]-oriented nanowires with a narrow (001) sidewall and [111]-oriented nanowires have the lightest effective mass among the considered nanowires.

Orientation and size effects on electronic structure of rectangular cross-sectional Sn nanowires

In this paper we describe an effort to find correlations between low temperature photoluminescence spectroscopy (LTPL) and deep level transient spectroscopy (DLTS) of electron irradiated samples annealed from 25 °C to 1700 °C in 100 °C steps. We report on thermal histories of defect centers created by 170 keV and 1 MeV electron irradiation, as observed by LTPL only. The DLTS results on "twin" samples are presented in a separate paper. Our results indicate that in n-type 4H SiC there is no correlation between the Z1/Z2 center in DLTS and the L1 peak of the DI center seen in LTPL. In p-type 4H SiC we do not find a correlation between a 350 meV DLTS peak above the valence band and the LTPL L1 peak of the DI center. Consequently, we cannot find evidence for a 350 meV ground state postulated in the “Pseudo–Donor” model [3].

Thermal Histories of Defect Centers as Measured by Low Temperature Photoluminescence in n- and p-Type 4H SiC Epilayers Generated by Irradiation with 170 keV or 1 MeV Electrons

In electric power conversion systems of power infrastructures, electric vehicles, and power supplies, Si-based power semiconductor devices are employed as a key hardware. Reduction of power dissipation in the conversion systems is strongly required for energy saving. In particular, ultrahigh-voltage power converters with high efficiency are essential to realize a stable and highly efficient electric power network by optimizing the use of solar power and wind-generated power in the future. The efficiency of power converters/inverters strongly relies on the performance of power semiconductor devices employed in the power electronic systems. Silicon carbide (SiC) is a newly-emerging wide bandgap semiconductor, by which high-voltage, low-loss power devices can be realized owing to its superior properties [1-3]. The major features of SiC power devices include high-voltage blocking capability, low on-state resistance, fast switching speed, and high-temperature operation.

Tsunenobu Kimoto

Papers

Impact of annealing temperature on surface passivation of SiC epitaxial layers with deposited SiO 2 followed by POCl 3 annealing

MANUFACTURING METHOD OF SiC SEMICONDUCTOR ELEMENT

Orientation and size effects on electronic structure of rectangular cross-sectional Sn nanowires

Thermal Histories of Defect Centers as Measured by Low Temperature Photoluminescence in n- and p-Type 4H SiC Epilayers Generated by Irradiation with 170 keV or 1 MeV Electrons

Junction technology in SiC for high-voltage power devices