Y. Takeda

Publication List Details

Period

1957 - 2008

Number

246

Co-Authors

Electronic structure of Ga$_{1-x}$Cr$_{x}$N and Si-doping effects studied by photoemission and X-ray absorption spectroscopy (2008)

Song, G. S., Kobayashi, M., Hwang, J. I., Kataoka, T., Takizawa, M., Fujimori, A., ...

The electronic structure of the magnetic semiconductor Ga$_{1-x}$Cr$_{x}$N and the effect of Si doping on it have been investigated by photoemission and soft x-ray absorption spectroscopy. We have...

Abundances of lithium, sodium, and potassium in Vega (2008)

Takeda, Y.

Vega's photospheric abundances of Li, Na, and K were determined by using considerably weak lines measured on the very high-S/N spectrum, while the non-LTE correction and the gravity-darkening...

Local electronic structure of Cr in the II-VI diluted ferromagnetic semiconductor Zn$_{1-x}$Cr$_x$Te (2008)

Kobayashi, M., Ishida, Y., Hwang, J. I., Song, G. S., Fujimori, A., ...

The electronic structure of the Cr ions in the diluted ferromagnetic semiconductor Zn$_{1-x}$Cr$_x$Te ($x=0.03$ and 0.15) thin films has been investigated using x-ray magnetic circular dichroism...

Hybridization between the conduction band and 3d orbitals in the oxide-based diluted magnetic semiconductor In$_{2-x}$V$_x$O$_3$ (2008)

Kobayashi, M., Ishida, Y., Hwang, J. I., Song, G. S., Takizawa, M., Fujimori, A., ...

The electronic structure of In$_{2-x}$V$_x$O$_3$ ($x=0.08$) has been investigated using photoemission spectroscopy (PES) and x-ray absorption spectroscopy (XAS). The V $2p$ core-level PES and XAS...

Nature of magnetic coupling between Mn ions in as-grown Ga$_{1-x}$Mn$_{x}$As studied by x-ray magnetic circular dichroism (2008)

Takeda, Y., Kobayashi, M., Okane, T., Ohkochi, T., Okamoto, J., Saitoh, Y., ...

The magnetic properties of as-grown Ga$_{1-x}$Mn$_{x}$As have been investigated by the systematic measurements of temperature and magnetic field dependent soft x-ray magnetic circular dichroism...

Systematic changes of the electronic structure of the diluted ferromagnetic oxide Li-doped Ni$_{1-x}$Fe$_x$O with hole doping (2007)

Kobayashi, M., Hwang, J. I., Song, G. S., Ooki, Y., Takizawa, M., Fujimori, A., ...

The electronic structure of Li-doped Ni$_{1-x}$Fe$_x$O has been investigated using photoemission spectroscopy (PES) and x-ray absorption spectroscopy (XAS). The Ni $2p$ core-level PES and XAS spectra...

Photoemission and x-ray absorption studies of valence states in (Ni,Zn,Fe,Ti)$_{3}$O$_{4}$ thin films exhibiting photo-induced magnetization (2007)

Kobayashi, M., Ooki, Y., Takizawa, M., Song, G. S., Fujimori, A., Takeda, Y., ...

By means of photoemission and x-ray absorption spectroscopy, we have studied the electronic structure of (Ni,Zn,Fe,Ti)$_{3}$O$_{4}$ thin films, which exhibits a cluster glass behavior with a...

Soft x-ray magnetic circular dichroism study of Ca_1-xSr_xRuO_3 across the ferromagnetic quantum phase transition (2007)

Okamoto, J., Okane, T., Saitoh, Y., Terai, K., Muramatsu, Y., ...

Ca_1-xSr_xRuO_3, which is ferromagnetic for Sr concentration x > 0.3, has been studied by x-ray magnetic circular dichroism (XMCD) in Ru 3p and O 1s core-level x-ray absorption. XMCD signals appear...

X-ray magnetic circular dichroism and photoemission study of the diluted ferromagnetic semiconductor Zn$_{1-x}$Cr$_x$Te (2007)

Ishida, Y., Kobayashi, M., Hwang, J. I., Takeda, Y., Okane, T., ...

We have performed x-ray magnetic circular dichroism (XMCD) and valence-band photoemission studies of the diluted ferromagnetic semiconductor Zn$_{1-x}$Cr$_x$Te. XMCD signals due to ferromagnetism...

Depth profile high-energy spectroscopic study of Mn-doped GaN prepared by thermal diffusion (2007)

Hwang, J. I., Osafune, Y., Kobayashi, M., Ebata, K., Ooki, Y., Ishida, Y., ...

We have performed an $in$-$situ$ depth profile study of Mn-doped GaN prepared by a low temperature thermal diffusion method using photoemission and x-ray absorption spectroscopy. It was revealed from...

Soft x-ray magnetic circular dichroism study of weakly ferromagnetic Zn$_{1-x}$V$_x$O thin film (2006)

Ishida, Y., Hwang, J. I., Kobayashi, M., Takeda, Y., Mamiya, K., Okamoto, J., ...

We performed a soft x-ray magnetic circular dichroism (XMCD) study of a Zn$_{1-x}$V$_x$O thin film which showed small ferromagnetic moment. Field and temperature dependences of V 2$p$ XMCD signals...

Raman scattering in $CaFeO_{3}$ and $La_{0.33}Sr_{0.67}FeO_{3}$ across the charge-disproportionation phase transition (2005)

Ghosh, Shankar, Kamaraju, N, Seto, M, Fujimori, A, Takeda, Y, Ishiwata, S, ...

Temperature-dependent micro-Raman studies of orthorhombic $CaFeO_{3}$ and rhombohedral $La_{0.33}Sr_{0.67}FeO_{3}$ were carried out with an aim to study the role of a lattice in the formation of the...

Characterization of Magnetic Components in the Diluted Magnetic Semiconductor Zn$_{1-x}$Co$_x$O by X-ray Magnetic Circular Dichroism (2005)

Kobayashi, M., Ishida, Y., Hwang, J. L., Mizokawa, T., Fujimori, A., Mamiya, K., ...

We report on the results of x-ray absorption (XAS), x-ray magnetic circular dichroism (XMCD), and photoemission experiments on {\it n}-type Zn$_{1-x}$Co$_x$O ($x=0.05$) thin film, which shows...

Highly polarized electrons from GaAs–GaAsP and InGaAs–AlGaAs strained-layer superlattice photocathodes (2005)

Nishitani, T., Nakanishi, T., Yamamoto, M., Okumi, S., Furuta, F., Miyamoto, M., ...

GaAs–GaAsP and InGaAs–AlGaAs strained-layer superlattice photocathodes are presented as emission sources for highly polarized electron beams. The GaAs–GaAsP cathode achieved a maximum...

Raman scattering in $CaFeO_{3}$ and $La_{0.33}Sr_{0.67}FeO_{3}$ across the charge-disproportionation phase transition (2005)

Ghosh, Shankar, Kamaraju, N, Seto, M, Fujimori, A, Takeda, Y, Ishiwata, S, ...

Temperature-dependent micro-Raman studies of orthorhombic $CaFeO_{3}$ and rhombohedral $La_{0.33}Sr_{0.67}FeO_{3}$ were carried out with an aim to study the role of a lattice in the formation of the...

Spectroscopic Studies of Extremely Metal-Poor Stars with Subaru/HDS:I. Observational Data (2004)

Honda, S., Aoki, W., Ando, H., Izumiura, H., Kajino, T., Kambe, E., ...

We have obtained high-resolution (R $\simeq$ 50,000 or 90,000), high-quality (S/N $\ga$ 100) spectra of 22 very metal-poor stars ([Fe/H] $\la$ -2.5) with the High Dispersion Spectrograph fabricated...

NB-3/Notch1 pathway via Deltex1 promotes neural progenitor cell differentiation into oligodendrocytes (2004)

Cui, XY, Hu, QD, Tekaya, M, Shimoda, Y, Ang, BT, Nie, DY, ...

Neurons and glia in the vertebrate central nervous system arise in temporally distinct, albeit overlapping, phases. Neurons are generated first followed by astrocytes and oligodendrocytes from common...

F3/contactin acts as a functional ligand for notch during oligodendrocyte maturation (2003)

Hu, QD, Ang, BT, Karsak, M, Hu, WP, Cui, XY, Duka, T, ...

Axon-derived molecules are temporally and spatially required as positive or negative signals to coordinate oligodendrocyte differentiation. Increasing evidence suggests that, in addition to the...

Different routes to charge disproportionation in perovskites-type Fe oxides (2002)

Matsuno, J., Mizokawa, T., Fujimori, A., Takeda, Y., Kawasaki, S., Takano, M.

Iron perovskites CaFeO_3 and La_{0.33}Sr_{0.67}FeO_3 show charge disproportionation, resulting in charge-ordered states with Fe^{3+}:Fe^{5+} =1:1 and =2:1, respectively. We have made photoemission...

Chemical potential shift in La(1-x)Sr(x)MnO(3): Photoemission test of the phase separation scenario (2002)

Matsuno, J., Fujimori, A., Takeda, Y., Takano, M.

We have studied the chemical potential shift in La(1-x)Sr(x)MnO(3) as a function of doped hole concentration by core-level x-ray photoemission. The shift is monotonous, which means that there is no...

Chemical composition of carbon-rich, very metal-poor subgiant LP625-44 observed with the Subaru/HDS (2002)

Aoki, W., Ando, H., Honda, S., Iye, M., Izumiura, H., Kajino, T., ...

We have obtained a high resolution (R~90,000) spectrum of the carbon- and s-process-element-rich, very metal-poor ([Fe/H]=-2.7) subgiant LP625-44, as well as that of HD140283 (a metal-poor subgiant...

Photospheric Abundances of Volatile and Refractory Elements in Planet-Harboring Stars (2001)

Takeda, Y., Sato, B., Kambe, E., Aoki, W., Honda, S., Kawanomoto, S., ...

By using the high-dispersion spectra of 14 bright planet-harboring stars (along with 4 reference stars) observed with the new coude echelle spectrograph at Okayama Astrophysical Observatory, we...

Behavior of Sulfur Abundances in Metal-Poor Giants and Dwarfs (2001)

Takada-Hidai, M., Takeda, Y., Sato, S., Honda, S., Sadakane, K., Kawanomoto, S., ...

LTE and NLTE abundances of sulfur in 6 metal-poor giants and 61 dwarfs (62 dwarfs, including the Sun) were explored in the range of -3 \lsim [Fe/H] \lsim $+0.5$ using high-resolution, high...

Oxygen Abundance Determination in Very Metal-Deficient Giants: Permitted O I Lines Versus Forbidden [O I] Lines (2000)

Takeda, Y., Takada-Hidai, M., Sato, S., Sargent, W. L. W., Lu, L., Barlow, T. A., ...

The abundance of oxygen was determined for selected very metal-poor G-K stars (six giants and one turn-off star) based on the high S/N and high-resolution spectra observed with Keck HIRES in the red...

Central Rotation Curves of Spiral Galaxies (1999)

Sofue, Y., Tutui, Y., Honma, M., Tomita, A., Takamiya, T., Koda, J., ...

We present high-resolution central-to-outer rotation curves for Sb, SBb, Sc, and SBc galaxies. We discuss their general characteristics, particularly their central behavior, as well as dependencies...

Process and Properties of PM Al-Si-X Alloys. (1998)

Takeda, Y., Odani, Y., Hayashi, T., Akechi, K.

Alloys are needed by the automotive, home appliance, and other civil industries to replace cast iron and steel products; high strength, wear resistance, high modulus of elasticity, thermal expansion,...

Brittle and Ductile Creep Rupture Life Prediction of 1CrMoV Steel Notched Thick Plates. (1998)

Ando, K., Takeda, Y., Takezoe, K.

An analytical prediction method of brittle and ductile creep rupture life of 1CrMoV steel notched thick plate is proposed; rupture time is evaluated as a sum of crack growth life t(sub p) and crack...

Microstructure and Mechanical Properties of P/M Al-Si-X Alloy. (1998)

Takeda, Y., Odani, Y., Hayashi, T., Akechi, K.

Air-atomized Si-2024 is shown to have an extended eutectic silicon content of 17% and have a simple mixture of fine eutectic silicon crystals and an aluminum matrix; the addition of Fe and/or Ni is...

Mechanical Properties and Oxidation Resistance of Ti5Si3 and (Ti,X)5Si3 Intermetallic Compounds. (1998)

Murata, Y., Higuchi, T., Takeda, Y., Morinaga, M., Yukawa, N.

The solid solubilities of Ti5Si3 with vanadium and niobium additions were determined to be 18.5 at% and 15.6 at%; the mechanical properties of pure and alloyed Ti5Si3 were studied; the microhardness...

Al-Fe-X Alloys Consolidated by Powder Forging Without Lateral Flow. (1998)

Kondoh, K., Kaji, T., Hayashi, T., Takeda, Y.

This paper presents a study of Al-8 wt%Fe alloys consolidated by powder forging without lateral flow. Results of tensile tests at room temperature and at 373-573 K show that UTS was 402 MPa, higher...

Mechanical Properties and Oxidation Resistance of High Purity TiAl Intermetallic Compounds. (1998)

Murata, Y., Morinaga, M., Shimamura, Y., Takeda, Y., Miyazaki, S.

The mechanical properties and oxidation resistance of high purity TiAl intermetallic compounds were investigated. Ductility, microstructure, fracture, and grain boundaries were compared to ordinary...

Electrical Conductivity of Tetragonal Stabilized Zirconia. (1998)

Yamamoto, O., Takeda, Y., Kanno, R., Kohno, K.

The electrical conductivity change on annealing for tetragonal stabilized zirconia (TZP) was studied with the help of a.c. impedance dispersion analysis techniques. The dependences of the...

First Beam Tests Of The Ins Split Coaxial Rfq For Radioactive Nuclei (1998)

S. Arai, A. Imanishi, K. Niki, M. Okada, Y. Takeda, E. Tojyo, ...

A 25.5-MHz split coaxial RFQ has come into operation at INS. This linac was designed so as to accelerate ions with a charge-tomass ratio greater than 1/30 from 2 to 172 keV/u. The maximum intervane...

Temperature-dependent photoemission spectral weight in $La_{0.6}Sr_{0.4}MnO_3$ (1996)

Sarma, DD, Shanthi, N, Krishnakumar, SR, Saitoh, T, Mizokawa, T, Sekiyama, A, ...

We report temperature-dependent redistribution of spectral weight in photoemission spectra of $La_{0.6}Sr_{0.4}MnO_3$ over a wide energy range of several eV. We attribute this to a change in the...

Temperature-dependent photoemission spectral weight in $La_{0.6}Sr_{0.4}MnO_3$ (1996)

Sarma, DD, Shanthi, N, Krishnakumar, SR, Saitoh, T, Mizokawa, T, Sekiyama, A, ...

We report temperature-dependent redistribution of spectral weight in photoemission spectra of $La_{0.6}Sr_{0.4}MnO_3$ over a wide energy range of several eV. We attribute this to a change in the...

Iodometric method of the determination of the exposed damage surface of cereal grain (1995)

A. Miś, S. Grundas, Y. Takeda, S. Hizukuri

In this paper, a method for determining the area of the exposed damage surface of grain endosperm by means of the amperometric measurement of iodine adsorption has been presented.According to the...

Some determinants of morphology and release rate from poly()lactic acid microspheres (1990)

Kishida, A., Dressman, Jennifer B., Yoshioka, S., Aso, Y., Takeda, Y.

Morphology and release rate from poly()lactic acid microspheres were studied as a function of drug loading, drug lipophilicity and solvent evaporation rate. Sudan III was used to exemplify lipophilic...

LOCAL STRUCTURE IN InGaAsP QUATERNARY ALLOYS (1986)

Oyanagi, H., Takeda, Y., Matsushita, T., Ishiguro, T., Sasaki, A.

The local structure of InGaAsP quaternary alloys epitaxially grown on InP substrates has been studied by EXAFS and near-edge structure. The bimodal distribution of bondlength at both cation (In, Ga)...

ULTRASONIC STUDY OF SINTERED SiC AT LOW TEMPERATURES (1986)

Hikata, A., Elbaum, C., Inomata, Y., Orange, G., Takeda, Y.

We investigated the temperature dependence, at low temperatures (< 1 K), of sound velocity in sintered silicon carbide samples, containing three different sintering additives, boron or beryllium...

LOCAL STRUCTURE IN InGaAsP QUATERNARY ALLOYS (1986)

Oyanagi, H., Takeda, Y., Matsushita, T., Ishiguro, T., Sasaki, A.

The local structure of InGaAsP quaternary alloys epitaxially grown on InP substrates has been studied by EXAFS and near-edge structure. The bimodal distribution of bondlength at both cation (In, Ga)...

ULTRASONIC STUDY OF SINTERED SiC AT LOW TEMPERATURES (1986)

Hikata, A., Elbaum, C., Inomata, Y., Orange, G., Takeda, Y.

We investigated the temperature dependence, at low temperatures (< 1 K), of sound velocity in sintered silicon carbide samples, containing three different sintering additives, boron or beryllium...