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Effect of Pressure on the Intermediate-valence Semiconductor SmB6 : 11B-NMR
Kohei Nishiyama,Takeshi Mito,Ko-ichi Ueda,Takehide Koyama,Takao Kohara,Gabriel Prist´aˇs,Slavom´ır Gab´ani,Mari´an Reiffers,Karol Flachbart,Yasuhiro Komaki,Mitsutane Kokubu,Hideto Fukazawa,and Yoh Koh 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.62 No.12
We report the first high-pressure 11B-NMR studies above 3 GPa on the intermediate-valencesemiconductor SmB6. A 11B-NMR line obtained at 4.9 GPa, the highest pressure for the measurements,and at 1.9 K shows quite similar a line shape to that at ambient pressure, indicating nostructural or magnetic phase transition up to this pressure. The temperature dependence of thespin lattice relaxation rate 1/T1 at 4.9 GPa still exhibits an activation-type temperature dependencecharacteristic of semiconductors, which reveals an obvious decrease in the insulating gap byabout 30% compared to the gap at ambient pressure. The present experimental facts of a finiteinsulator gap and no magnetic order at 4.9 GPa are consistent with recent transport measurementsperformed under better hydrostatic pressures.
Research Activities on a MIR-FEL and Table-Top THz Generation in Kyoto University
H. Ohgaki,T. Kii,K. Masuda,M. A. Bakr,K. Higashimura,R. Kinjo,S. Ueda,T. Sonobe,Y. U. Jeong,K. Yoshida 한국물리학회 2010 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.57 No.21
Free Electron Lasers (FEL), which could be useful for developing energy materials, have been exploited at the Institute of Advanced Energy, Kyoto University. A mid-infrared FEL has been developed, and FEL gain saturation at 13.2 µm was achieved for the first time in May 2008. A FEL beam characterization was performed. A macro pulse energy of 5 mJ/pulse and a peak power of about 3 MW were achieved. A FEL beam transport system was constructed in the user room. Furthermore a tabletop THz FEL amplifier for the spectral range from 150 to 300 µm, which consists of a photocathode RF gun and an undulator, has been proposed to strengthen the materials research. For evaluation of the proposed design, a start-to-end simulation was carried out. An output power of about 350 kW is expected with the proposed system. Free Electron Lasers (FEL), which could be useful for developing energy materials, have been exploited at the Institute of Advanced Energy, Kyoto University. A mid-infrared FEL has been developed, and FEL gain saturation at 13.2 µm was achieved for the first time in May 2008. A FEL beam characterization was performed. A macro pulse energy of 5 mJ/pulse and a peak power of about 3 MW were achieved. A FEL beam transport system was constructed in the user room. Furthermore a tabletop THz FEL amplifier for the spectral range from 150 to 300 µm, which consists of a photocathode RF gun and an undulator, has been proposed to strengthen the materials research. For evaluation of the proposed design, a start-to-end simulation was carried out. An output power of about 350 kW is expected with the proposed system.
Eiteneer, D.,Palsson, G.K.,Nemsak, S.,Gray, A.X.,Kaiser, A.M.,Son, J.,LeBeau, J.,Conti, G.,Greer, A.A.,Keqi, A.,Rattanachata, A.,Saw, A.Y.,Bostwick, A.,Rotenberg, E.,Gullikson, E.M.,Ueda, S.,Kobayashi Elsevier Scientific Pub. Co 2016 Journal of electron spectroscopy and related pheno Vol.211 No.-
LaNiO<SUB>3</SUB> (LNO) is an intriguing member of the rare-earth nickelates in exhibiting a metal-insulator transition for a critical film thickness of about 4 unit cells [Son et al., Appl. Phys. Lett. 96, 062114 (2010)]; however, such thin films also show a transition to a metallic state in superlattices with SrTiO<SUB>3</SUB> (STO) [Son et al., Appl. Phys. Lett. 97, 202109 (2010)]. In order to better understand this transition, we have studied a strained LNO/STO superlattice with 10 repeats of [4 unit-cell LNO/3 unit-cell STO] grown on an (LaAlO<SUB>3</SUB>)<SUB>0.3</SUB>(Sr<SUB>2</SUB>AlTaO<SUB>6</SUB>)<SUB>0.7</SUB> substrate using soft x-ray standing-wave-excited angle-resolved photoemission (SWARPES), together with soft- and hard- x-ray photoemission measurements of core levels and densities-of-states valence spectra. The experimental results are compared with state-of-the-art density functional theory (DFT) calculations of band structures and densities of states. Using core-level rocking curves and x-ray optical modeling to assess the position of the standing wave, SWARPES measurements are carried out for various incidence angles and used to determine interface-specific changes in momentum-resolved electronic structure. We further show that the momentum-resolved behavior of the Ni 3d e<SUB>g</SUB> and t<SUB>2g</SUB> states near the Fermi level, as well as those at the bottom of the valence bands, is very similar to recently published SWARPES results for a related La<SUB>0.7</SUB>Sr<SUB>0.3</SUB>MnO<SUB>3</SUB>/SrTiO<SUB>3</SUB> superlattice that was studied using the same technique (Gray et al., Europhysics Letters 104, 17004 (2013)), which further validates this experimental approach and our conclusions. Our conclusions are also supported in several ways by comparison to DFT calculations for the parent materials and the superlattice, including layer-resolved density-of-states results.
Adsorption and Reaction of CO and NO on Ir(111) Under Near Ambient Pressure Conditions
Ueda, K.,Suzuki, K.,Toyoshima, R.,Monya, Y.,Yoshida, M.,Isegawa, K.,Amemiya, K.,Mase, K.,Mun, B. S.,Arman, M. A. Springer Science + Business Media 2016 Topics in catalysis Vol.59 No.5
<P>The adsorption and reaction of CO and NO on Ir(111) have been studied by near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) together with low-energy electron diffraction, scanning tunneling microscopy, and mass spectroscopy (MS). Under both ultrahigh vacuum (UHV) and NAP conditions CO molecules occupy on-top sites of the Ir(111) surface at room temperature (RT) by forming two-dimensional clusters. Exposure to NO under UHV conditions at RT induces partially dissociative adsorption, while NAP NO exposure leads to a Ir(111) surface that is covered by molecular NO. We conducted in-operando NAP-XPS/MS observation of the NO + (CO)-C-13 reaction under a NAP condition as a function of temperature. Below 210 degrees C adsorption of NO is inhibited by CO, while above 210 degrees C the CO inhibition is released due to partial desorption of CO and dissociative adsorption of NO starts to occur leading to associative formation of N-2. Under the most active condition studied here the Ir surface is covered by a dense co-adsorption layer consisting of on-top CO, atomic N and O, which suggests that this reaction is not a NO-dissociation-limited process but a N-2/CO2 formation-limited process.</P>
Mahmood A. Hamed,Seiichi Nakata,Ramadan H. Sayed,Hiromi Ueda,Badawy S. Badawy,Yoichi Nishimura,Takuro Kojima,Noboru Iwata,Ahmed R. Ahmed,Khalid Dahy,Naoki Kondo,Kenji Suzuki 대한이비인후과학회 2016 Clinical and Experimental Otorhinolaryngology Vol.9 No.4
Cholesteatoma is a cystic non tumorous lesion of the temporal bone that has the ability to destroy nearby structures by its power to cause bone resorption and as a result, fatal complications prevail. We aimed to conduct a comprehensive review for pathogenesis of acquired cholesteatoma, bone resorption mechanisms, and offer a future vision of this serious disease. We have reviewed different theories for pathogenesis of acquired cholesteatoma including the most relevant and updated ones with special emphasis on the mechanisms of bone resorption through Medline/PubMed research using the keywords ‘aetiopathogenesis, bone resorption, acquired cholesteatoma, temporal bone, and cytokines.’ In order to strengthen our study, we searched the reference lists of identified reviews. Cholesteatoma is a subject of debate among otolaryngologists since it was prescribed firstly. Over many decades, several theories were postulated for aetiopathogenesis of cholesteatoma with a tendency to follow more than one theory to explain the proper nature of that disease. Until now, the mechanism of bone resorption has yet to be more clarified. In the last century, a leap has occurred in the field of biomolecular cholesteatoma research which improved our knowledge about its pathophysiology and bone destructive mechanism. However, surgery is still the only available treatment. We conclude that discovery of new therapeutic choices for cholesteatoma other than surgery by the use of anti-growth, anti-proliferative, apoptotic agents as well as medications that antagonize osteoclastogenesis should be the main concern in the future clinical and experimental research work. Also, searching for predictors of the aggressiveness of cholesteatoma can affect the timing of intervention and prevent occurrence of complications.
Hisashi Koiwa,,Stephane Hausmann,Bang, Woo-Young,Akihiro Ueda,Naoko Kondo,Akihiro Hiraguri,Toshiyuki Fuku,hara,Bahk, Jeong-Dong,Yun, Dae-Jin,Ray A. Bressan,Paul M. Hasegawa,Stewart Shuman Plant molecular biology and biotechnology research 2004 Plant molecular biology and biotechnology research Vol.2004 No.-
Transcription and mRNA processing are regulated by phosphorylation and dephosphorylation of the C-terminal domain (CTD) of RNA polymerase Ⅱ, which consists of tandem repeats of a Y^(1)S^(2)P^(3)T^(4)S^(5)P^(6)S^(7) heptapeptide. Previous studies showed that members of the plant CTD phosphatase-like (CPL) protein family differentially regulate osmotic stress-responsive and abscisic acid-responsive transcription in Arabidopsis thaliana. Here we report that AtCPL1 and AtCPL2 specifically dephosphorylate Ser-5 of the CTD heptad in Arabidopsis RNA polymerase Ⅱ, but not Ser-2. An N-terminal catalytic domain of CPL1, which suffices for CTD Ser-5 phosphatase activity in virto, includes a signature DXDXT acylphosphatase motif, but lacks a breast cancer 1 CTD, which is an essential component of the fungal and metazoan Fcp1 CTD phosphatase enzymes. The CTD of CPL1, which contains two putative double-stranded RNA binding motifs, is essential for the in vivo function of CPL1 and includes a C-terminal 23-aa signal responsible for its nuclear targeting. CPL2 has a similar domain structure but contains only one double-stranded RNA binding motif. Combining mutant alleles of CPL1 and CPL2 causes synthetic lethality of the male but not the female gametes. These results indicate that CPL1 and CPL2 exemplify a unique family of CTD Ser-5-specific phosphatases with an essential role in plant growth and development.
Application of MIR-FEL Irradiation to Selectively Excite Phonons in Wide-gap Semiconductors
Kyohei Yoshida,Taro Sonobe,M. A. Bakr,Y. W. Choi,Ryota Kinjo,M. Omer,Masato Takasaki,Satoshi Ueda,Naoki Kimura,Keiichi Ishida,Kai Masuda,Toshiteru Kii,Hideaki Ohgaki 한국물리학회 2011 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.59 No.51
A mid-infrared free electron laser (MIR-FEL) (5 - 20 μm) facility (KU-FEL: Kyoto University Free Electron Laser) was constructed to aid in various energy science researchers at the Institute of Advanced Energy, Kyoto University. In May 2008, the first power saturation at 13.2 μm was achieved. A pilot application to evaluate selective phonon excitation processes in solid materials by irradiating with MIR-FEL was implemented, and a preliminary experiment without FEL irradiation was conducted. N-doped silicon carbide (SiC) was selected as a sample material due to its unique electrical property where the lattice vibration and electronic structure are coupled. Two peaks at 1.8 - 2.4 eV and 2.4 - 2.8 eV, which showed strong temperature dependences in both their intensities and peak energy, were observed. These tendencies could be explained by a donor-acceptor pair luminescence (DAP) model with impurity and defects in the SiC sample. The results imply that we can verify the selective phonon excitation by investigating the change of PL spectrum introduced by MIR-FEL irradiation.
Short-term Response of Vegetation to Cattle Grazing in an Abandoned Orchard in Southwestern Japan
Hayashi, K.,Ikeda, K.,Ueda, A.,Fumita, T.,Etoh, T.,Gotoh, T. Asian Australasian Association of Animal Productio 2006 Animal Bioscience Vol.19 No.4
An abandoned mandarin orange orchard in southwestern Japan was set-stocked by Japanese Black cows at two stocking rates (1.0 and 2.0 animals/ha), and vegetation dynamics and diet selection by cattle were monitored for two years, in an effort to obtain information on effective use of abandoned agricultural fields for low-cost animal production and environmental conservation. Two dominant species at the commencement of grazing, kudzu (Pueraria lobata Ohwi) and tall goldenrod (Solidago altissima L.), showed different responses to grazing during the two years; the composition of kudzu decreased, contrasting with that of tall goldenrod which increased at both stocking rates. This was caused by high preference for kudzu and avoidance or low preference for tall goldenrod by cattle. Retrogression of vegetation due to cattle disturbances occurred at both stocking rates, with the high stocking rate leading to a lower degree of succession than the low stocking rate. It was shown that cattle grazing, particularly at a high stocking rate, was effective in the management of vegetation of an abandoned orchard.