分光偏光解析等によるSiC酸化膜の評価

We have developed the method of obtaining the refractive indices of SiC/oxide interfaces by use of spectroscopic ellipsometry, and by using this method we have characterized SiC/oxide interfaces obtained by various oxidation methods and/or post oxidation annealing (POA). We have designed and fabricated the system with which in situ spectroscopic ellipsometry measurements can be carried out. We have observed the initial oxidation stage of SiC. We have also observed the changes of the refractive indices of interfaces by annealing in Ar atmosphere (Ar POA). The changes of atomic bond states at the interface by Ar POA were also observed by angle-resolved XPS and UPS, and compared with the results obtained form optical measurements and C-V measurements. We have developed the measurement method of obtaining carrier density and mobility distribution in SiC wafers by use of microscopic FT-IR. We have shown that the values obtained by this method well agree with those obtained from Hall measurements, suggesting that the method is useful to characterize electrical properties of SiC wafers quantitatively, non-destructively and without contact.textapplication/pdfdepartmental bulletin pape

A balloon-borne very long baseline interferometry experiment in the stratosphere: Systems design and developments

application/pdfAdvances in Space Research. 2019, 63 (1), P.779-793journal articl

Synthesis of Au-assisted GaAs Nanowires on Si Substrate by Pulsed-jet Epitaxy Method

GaAs nanowires (NWs) assisted Au catalyst on the Si (111) substrate have been synthesized by employing the pulsed-jet epitaxy method. The effect of growth conditions was evaluated by changing the formation and the growth direction of the NWs. Increasing the Au droplet diameter, the number density of NWs reduced and the length of NWs became longer. In the higher growth temperature, the distribution of the growth direction on the nanowire axis was small, and the NWs grow to perpendicular direction to a substrate. However, the desorption of As restrain the growth of NWs more than 550 ℃.departmental bulletin pape

Observation of B̅0→DsJ*(2317)+K- Decay

journal articl

Solar neutrino measurements in Super-Kamiokande-II

The results of the second phase of the Super-Kamiokande solar neutrino measurement are presented and compared to the first phase. The solar neutrino flux spectrum and time variation as well as oscillation results are statistically consistent with the first phase and do not show spectral distortion. The timedependent flux measurement of the combined first and second phases coincides with the full period of solar cycle 23 and shows no correlation with solar activity. The measured 8B total flux is (2:38± 0.05(stat.)/begin+0.16 // -0.15/end (sys.)) × 10^6 cm^{-2} s^{-1} and the day-night difference is found to be (-6.3 ±4.2(stat.)±3.7(sys.))%.There is no evidence of systematic tendencies between the first and second phases.journal articl

Abstracts of Vol.61 Nos.5･6, March 2010

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食品含有ナノ粒子による腸管免疫機構の破綻を介した消化管炎症反応の解明とリスク評価

application/pdf食品に含有するナノ粒子の消化器系における炎症反応の誘導作用を解明するため、ヒトマクロファージ様細胞THP-1および大腸腺癌細胞Caco-2を用い、ナノ粒子曝露による生存率の変化、活性酸素種（ROS）および炎症性サイトカインの産生について解析を行った。二酸化チタンのナノ粒子曝露により、ROSおよび炎症性サイトカインIL-1βの産生が増加する傾向が認められた。また一次粒径が同程度でも、酸化亜鉛の方が二酸化チタンより細胞の生存率の低下およびROSの産生を誘導する事が認められ、粒子の種類により細胞毒性作用、炎症反応誘導の機構に違いがあることが示唆された。The present study investigated the cytotoxicity, production of reactive oxygen species (ROS) and inflammatory cytokine induced by nano-TiO₂ and nano-ZnO particles using human monocytic leukemia cells (THP-1) and human colon cancer cells (Caco-2). The viability of THP-1 macrophages exposed to nano-ZnO was lower than that to nano-TiO₂ THP-1. The production of ROS and IL-1β showed a tendency to be increased by nano-TiO₂ particles. This study indicated that nano-TiO₂ particles may induce inflammation in THP-1 macrophages through production of ROS and IL-1β, and nano- ZnO particles were suggested to be more toxic to THP-1 macrophages than nano-TiO₂.2011年度～2012年度科学研究費補助金(研究活動スタート支援)研究成果報告書23890082research repor