著者

石渡 晋太郎

出版者

東京大学

雑誌

若手研究(A)

巻号頁・発行日

2011-04-01

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立方晶ペロブスカイトSrFeO3は、金属的伝導性とらせん磁性を併せもつ希有な酸化物として古くから知られていたが、単純ならせん磁性では説明できない磁気輸送特性を示すことから、スカーミオンなどのトポロジカルに新しいらせん磁性相の存在が期待されていた。本研究では、フローティングゾーン法と高圧合成法を組み合わせることで、SrFeO3およびその周辺物質の大型単結晶育成に世界で初めて成功し、磁化・抵抗・ホール抵抗測定から多彩な新奇らせん磁性相を含む磁気相図を確立した。さらに磁場中における偏極中性子回折実験を行うことで、この系が4つの磁気伝搬ベクトルを有するmulti-Qらせん磁性体であることを見いだした。

著者

浅田 篤

出版者

一般社団法人映像情報メディア学会

雑誌

テレビジョン (ISSN:03743470)

巻号頁・発行日

vol.14, no.2, pp.96-97, 1960-02-01

著者

具 本榮 伊藤 憲三

出版者

一般社団法人電子情報通信学会

雑誌

電子情報通信学会技術研究報告. WIT, 福祉情報工学 (ISSN:09135685)

巻号頁・発行日

vol.102, no.493, pp.45-50, 2002-11-30

被引用文献数

6

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我々は、様々な音の洪水の中で生活しており、高度情報社会では音の種類も益々多様になって来ている。そのような状況の中で、高齢者や難聴者の人たちが家の中で生活する時に重度と思われる「音」(これをここでは生活音と呼ぶ)を聴取できないという問題がある。これに対処するシステムとしては、いくつか販売されているが、十分な性能を有していない現状にある。本報告では、高齢者や難聴者支援を目的とした生活音識別システムを提案した。提案方式は、識別したい生活音信号の特徴量を事前に登録する「事前登録方式」である。信号の特徴量は、信号パワーとFFTスペクトル特性及びLPC包絡特性とした。実験の結果、13種類の生活音を99%以上で識別できることが分かった。

著者

三松 幸雄

出版者

東京大学教養学部哲学・科学史部会

雑誌

哲学・科学史論叢 (ISSN:13446185)

巻号頁・発行日

no.8, pp.79-137, 2006

著者

岸上 義〓 服部 正次 横山 泰 野村 裕 高橋 隆 桜宮 正子 宮脇 一男 橋本 良夫 横内 峻

出版者

特定非営利活動法人日本臨床細胞学会

雑誌

日本臨床細胞学会雑誌 (ISSN:03871193)

巻号頁・発行日

vol.7, no.1, 1968-06-30

著者

奥山眞紀子主任研究

出版者

[奥山眞紀子]

著者

Kanako Kawaura Asuka Saeki Takehiro Masumura Shigeto Morita Yasunari Ogihara

出版者

日本遺伝学会

雑誌

Genes & Genetic Systems (ISSN:13417568)

巻号頁・発行日

vol.86, no.4, pp.249-255, 2011 (Released:2011-12-29)

参考文献数

23

被引用文献数

3 8 2

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The plant chondriome confers a complex nature. The atp4 gene (formerly called orf25) of Aegilops crassa (CR) harbors the promoter sequence of the rps7 gene from common wheat (Triticum aestivum cv. Chinese Spring, CS). The rps7 gene of CR has the promoter sequence of CS atp6. The atp6 gene of CR contains an unknown sequence inside of its coding region. Since repeat sequences have been found around the breaking points, these structural alterations are most likely generated through homologous recombination. In this study, PCR analysis was performed to detect structural alterations in each of three lines: euplasmic lines of Ae. crassa, Chinese Spring, and alloplasmic Chinese Spring wheat with the cytoplasm of Ae. crassa ((cr)-CS). We found that each of these lines contained both genotypes, although mitochondrial genotypes of CR in Chinese Spring wheat and CS genotypes in Ae. crassa were still retained as minor fractions (less than 10%). On the other hand, CS mitochondrial gene frequencies in ((cr)-CS) were shown to be ca. 30%. SNP analysis after DNA sequencing of these genes indicated that minor types of all three mitochondrial genes in alloplasmic wheat contained the mitochondrial gene types from pollens. Since the frequencies of paternal mitochondrial gene types in F1 were about 20%, successive backcrossing increased the frequencies of paternal mitochondrial gene types to around 30% in alloplasmic wheat. Expression profiles of these mitochondrial genes were quantitatively analyzed by RT-PCR. Transcripts of paternal mitochondrial gene types were scarcely found. This suggests that minor fractions including paternal mitochondrial gene types are maintained and silenced in the descendants.

著者

渡邊 雅之 深澤 均 白石 不二雄 白石 寛明 塩澤 竜志 寺尾 良保

出版者

一般社団法人 日本環境化学会

雑誌

環境化学 (ISSN:09172408)

巻号頁・発行日

vol.14, no.1, pp.65-71, 2004-03-29 (Released:2010-05-31)

参考文献数

16

被引用文献数

4 5

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試験用離解機を用いて古紙原料の離解排水を作成し, そのBPA濃度を測定した。8種類の古紙原料のうち, 感熱紙で440mg/lと高濃度のBPAが検出された。さらに, ワープロ用あるいはFAX用の11種類の感熱紙について検討したところ, 1999年以前に製造された感熱紙の離解排水で170~460mg/lのBPAが検出された。しかし, それ以降に製造された感熱紙ではBPA濃度が大きく低下することや, 顕色剤としてBPSあるいはBPS-monoPが検出されることが示された。これらのことから, 感熱紙の顕色剤としてBPAから他の製品への切り替えが進んでいることが示唆された。また, 増感剤としてm-テルフェニル, 4-ベンジルビフェニル, 1, 2-ビス (3-メチルフェノキシ) エタン及びベンジル2-ナフチルエーテルも検出された。感熱紙に含まれる可能性のある物質について酵母ツーハイブリッド・アッセイ法によるエストロゲン・アゴニスト試験を行ったところ, 4-ヒドロキシ安息香酸ベンジルとトリフェニルメタンにBPAより強い活性が認められた。

著者

Ahart Muhtar Hushur Anwar Bing Yonghong Ye Zuo-Guang Hemley Russell J. Kojima Seiji

出版者

American Institute of Physics

雑誌

Applied physics letters (ISSN:00036951)

巻号頁・発行日

vol.94, no.14, pp.142906, 2009-04

被引用文献数

27

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Brillouin spectroscopy of Pb(Sc0.5Nb0.5)O3 single crystals reveals an order-disorder ferroelectric phase transition occurs at 110 °C upon cooling. A softening of the longitudinal acoustic (LA) mode is observed that can be attributed to the coupling between polar nanoregions and acoustic modes. A critical slowing down of the central peak, a feature of order-disorder ferroelectric phase transitions, is observed near Tc. The similarity in temperature dependences of the two kinds of relaxation times determined from the central peak and LA mode suggests that the changes in the central peak arise from local polarization fluctuations in the polar nanoregions.

著者

Tanaka Hisaaki Watanabe Shun-ichiro Ito Hiroshi Marumoto Kazuhiro Kuroda Shin-ichi

出版者

American Institute of Physics

雑誌

Applied physics letters (ISSN:00036951)

巻号頁・発行日

vol.94, no.10, pp.103308, 2009-03

被引用文献数

33 17

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Charge carrier concentration in operating field-effect transistor (FET) of regioregular poly(3-hexylthiophene) has been directly determined by electron spin resonance (ESR). ESR signals of field-induced polarons are observed around g=2.003 under the application of negative gate-source voltage (Vgs). Upon applying drain-source voltage (Vds), ESR intensity decreases linearly in the low Vds region, reaching to about 50% of the initial intensity at the pinch-off point (Vds~=Vgs). For larger absolute values of Vds, it becomes nearly Vds independent. These behaviors are well explained by the change in the carrier concentration obtained by the FET theory using gradual channel approximation.

著者

Kita Yuki Yoshida Shinichi Hosoi Takuji Shimura Takayoshi Shiraishi Kenji Nara Yasuo Yamada Keisaku Watanabe Heiji

出版者

American Institute of Physics

雑誌

Applied physics letters (ISSN:00036951)

巻号頁・発行日

vol.94, no.12, pp.122905, 2009-03

被引用文献数

8 8

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Change in the work function (WF) of the gate electrode material caused by the contact with Hf-based high-k gate dielectrics was investigated by means of the flat-band voltage (Vfb) shift in capacitance-voltage curves, and the interface dipole, which modifies the WF, was characterized by x-ray photoelectron spectroscopy. We observed a negative Vfb shift and corresponding interface dipole, which suggest the formation of oxygen vacancy (VO) in the Hf-based oxides. In contrast, we observed an opposite (positive) Vfb shift and interface dipole when Au electrodes were formed on cleaned Hf-based dielectrics. This indicates that Au–Hf bond hybridization at the Au/HfSiON interface also causes effective WF modulation, as theoretically predicted by Shiraishi et al. (Tech. - Dig. Int. Electron Devices Meet. 2005, 43).

著者

Moritomo Y. Nakada F. Kurihara Y.

出版者

American Institute of Physics

雑誌

Applied physics letters (ISSN:00036951)

巻号頁・発行日

vol.94, no.11, pp.111914, 2009-03

被引用文献数

5 4

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Electrochromism is extensively investigated for practical application of display and memory devices. To develop the material, reliable information on the optical and electronic properties of the solid film is indispensable. Here, we propose valence-differential spectroscopy that can selectively extract the spectral components related to the oxidized/reduced metal site. We applied the spectroscopy to Co2+–Fe2+delta and Co2+delta–Fe2+ cyanide films with finely control of averaged valence (delta) of the transition metal by external electric pulses. The spectroscopy revealed transition energy E, width Gamma, and oscillator strength f of the spectral components related to the transition metal.

著者

Hase Muneaki

出版者

American Institute of Physics

雑誌

Applied physics letters (ISSN:00036951)

巻号頁・発行日

vol.94, no.11, pp.112111, 2009-03

被引用文献数

18 6

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Ultrafast dephasing of the plasmonlike longitudinal optical phonon-plasmon coupled (LOPC) mode in highly doped n-GaAs has been investigated by using a femtosecond optical pump-probe technique with 40 THz bandwidth as a function of photodoping levels. The direct measurement of plasmon damping with the help of a wavelet analysis enables us to extract carrier (electron) mobility, which decreases with increasing the photodoping levels. It is found that the mobility is suppressed at high photodoping levels due to electron-hole scattering, while it is enhanced near a critical density, being plausibly attributed to the strong coherent coupling of the LO phonon with the plasmon.

著者

Xu Maojie Okada Arifumi Yoshida Shoji Shigekawa Hidemi

出版者

American Institute of Physics

雑誌

Applied physics letters (ISSN:00036951)

巻号頁・発行日

vol.94, no.7, pp.073109, 2009

被引用文献数

5 7

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Methods of forming various In nanostructures on Si surfaces are demonstrated. Using a high-index Si(311) surface, isolated nanotriangles and wires were grown by optimizing the deposition rate and substrate temperature. In contrast, nanodots were formed by the deposition of In on a Si(111)-In-31×31 surface at room temperature (RT) deposition. On a Si(111)-In-4×1/31×31 coexisting surface, nanowires were selectively grown in the Si(111)-In 4×1 area by RT deposition through the nucleation promoted by the boundary barrier produced by the surrounding 31×31 area. Details were studied using scanning tunneling microscopy.

著者

Fukata N. Mitome M. Bando Y. Seoka M. Matsushita S. Murakami K. Chen J. Sekiguchi T.

出版者

American Institute of Physics

雑誌

Applied physics letters (ISSN:00036951)

巻号頁・発行日

vol.93, no.20, pp.203106, 2008-11

被引用文献数

33 20

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Codoping of boron (B) and phosphorus (P) atoms was performed during the synthesis of silicon nanowires (SiNWs) by laser ablation. The observation of a local vibrational mode of B clearly showed B doping in codoped SiNWs, while Fano broadening due to heavy B doping disappeared, indicating compensation by P donors. The electrospin resonance signal of conduction electrons also disappeared due to compensation by B acceptors. These results indicate that codoping of B and P atoms was achieved in SiNWs during laser ablation.

著者

Tanimoto H. Yamada K. Mizubayashi H. Matsumoto Y. Naramaoto H. Sakai S.

出版者

American Institute of Physics

雑誌

Applied physics letters (ISSN:00036951)

巻号頁・発行日

vol.93, no.15, pp.151919, 2008-10

被引用文献数

7

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C60 films with thicknesses of 100–480 nm were deposited on Si reed substrates under in situ photoirradiation. In anelasticity measurements, no internal friction peaks associated with rotational motions of the C60 molecules were observed, and Young's modulus was 1.5 times larger than that of a pristine C60 material. X-ray diffraction patterns suggested that the face-centered cubic lattice was contracted by about 3% and locally distorted from the pristine C60 material. Raman spectra very similar to those reported for dimerized C60 were also obtained. These characteristics recovered to those of the pristine C60 materials after annealing the C60 films at 523 K. These results indicate uniform dimerization in C60 films deposited under in situ photoirradiation.

著者

Ko J.-H. Kojima S. Koo T.-Y. Jung J. H. Won C. J. Hur N. J.

出版者

American Institute of Physics

雑誌

Applied physics letters (ISSN:00036951)

巻号頁・発行日

vol.93, no.10, pp.102905, 2008-09

被引用文献数

69 45

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A strong relaxation mode was observed in the paraelectric phase of barium titanate (BaTiO3) single crystals by Brillouin scattering study and was found to correlate with the softening of the longitudinal acoustic mode and the increase in the hypersonic damping. These observations support the existence of polar percursors and their electrostrictive coupling with the strain caused by the acoustic waves, consistent with former studies evidencing off-centered Ti ions in the high-symmetry cubic phase. A critical slowing down has been clearly observed in the vicinity of the cubic-tetragonal phase transition, indicating order-disorder component contributes to the phase transition of BaTiO3.

著者

Chong S. V. Kadowaki K. Xia J. Idriss H.

出版者

American Institute of Physics

雑誌

Applied physics letters (ISSN:00036951)

巻号頁・発行日

vol.92, no.23, pp.232502, 2008-06

被引用文献数

34

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The magnetic behavior of titanium dioxide nanobelts has been investigated with and without Codoping. Room temperature ferromagnetism was observed when the Co-doped anatase TiO2nanobelts were prepared via vacuum annealing of 2.5 at. % Co-doped titanate nanobelts, whileannealing them in air resulted in paramagnetic ordering. Interestingly, by vacuum annealing theundoped titanate nanobelts under the same conditions, superparamagnetic ordering was observed inthe resulting anatase TiO2 nanobelts. The electron paramagnetic resonance of this latter sampleshows a strong symmetrical signal at g=2.003 suggesting some sort of exchange interactions amongthe localized electrons’ spin moments from single electron trapped in oxygen vacancies.

著者

Ootsuka Teruhisa Suemasu Takashi Chen Jun Sekiguchi Takashi Hara Yoshiaki

出版者

American Institute of Physics

雑誌

Applied physics letters (ISSN:00036951)

巻号頁・発行日

vol.92, no.19, pp.192114, 2008-05

被引用文献数

14

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We have evaluated the lifetime and diffusion length of photogenerated minority carriers (holes) in single-crystalline n-type beta-FeSi2 bulk grown by chemical vapor transport. The diffusion length measured by optical-beam-induced current agreed well with that measured by electron-beam-induced current, that is, 51 and 38 µm, respectively, for samples annealed at 800 °C for 8 h. The decay curve of photoconductivity obtained by 1.31 and 1.55 µm light pulses was well fitted by assuming a carrier lifetime of approximately a few microseconds. The mobility of photogenerated minority carriers was estimated to be approximately 200–360 cm2/V s from the measured lifetime and diffusion length.

著者

Uchida Noriyuki Mikami Youhei Kintoh Hiroshi Murakami Kouichi Fukata Naoki Mitome Masanori Hase Muneaki Kitajima Masahiro

出版者

American Institute of Physics

雑誌

Applied physics letters (ISSN:00036951)

巻号頁・発行日

vol.92, no.15, pp.153112, 2008-04

被引用文献数

5

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We have developed a robust method for fabricating Si nanoregions in silica glass using femtosecond laser processing. We attained a vivid formation of silicon-rich nanoregions site-selectively generated in SiO2 by irradiation of femtosecond laser pulses to the interface of a SiO2 substrate and deposited aluminum (Al) thin film, where the Al element acts as a gettering site for O atoms. Growth of high-density Si nanocrystals and amorphous Si was observed by transmission electron microscopy in the region that was multiply irradiated with the femtosecond laser. Furthermore, local annealing with a cw laser enhances the Si nanocrystal growth, which was determined by micro-Raman measurements.