Refine your search:     
Report No.
 - 
Search Results: Records 1-20 displayed on this page of 63

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

Journal Articles

Degradation prediction of a gamma-ray radiation dosimeter using InGaP solar cells in a primary containment vessel of the Fukushima Daiichi Nuclear Power Station

Okuno, Yasuki; Yamaguchi, Masafumi*; Okubo, Nariaki; Imaizumi, Mitsuru*

Journal of Nuclear Science and Technology, 57(4), p.457 - 462, 2020/04

 Times Cited Count:4 Percentile:57.07(Nuclear Science & Technology)

Indium gallium phosphide (InGaP) solar cell with a superior high-radiation resistance is expected to be a powerful candidate for a dosimeter under a high-radiation dose rate environment. In this study, in order to predict the lifetime as the dosimeter using the InGaP solar cell, we clarify the effect of minority-carrier diffusion length ($$L$$) on a radiation-induced current as a dose signal in the InGaP solar cell by irradiation tests and empirical calculations. In the irradiation tests, the short circuit current density ($$J_{rm sc}$$) as a function of the gamma-ray dose rate is measured to estimate the $$L$$ for the InGaP solar cell by irradiation tests. The operational lifetime as a detector using the InGaP solar cell under various dose rates is estimated by using the empirical calculations based on the relation between the L and absorbed dose. The results suggest that the dosimeter using InGaP solar cell is able to be used during more than 10 h in the primary containment vessel of the Fukushima Daiichi Nuclear Power Plant and it has a high potential of being a radiation-resistant dosimeter that would contribute to the decommissioning.

Journal Articles

${it In situ}$ three-dimensional X-ray reciprocal-space mapping of InGaAs multilayer structures grown on GaAs(001) by MBE

Sasaki, Takuo; Takahashi, Masamitsu; Suzuki, Hidetoshi*; Oshita, Yoshio*; Yamaguchi, Masafumi*

Journal of Crystal Growth, 425, p.13 - 15, 2015/09

 Times Cited Count:3 Percentile:34(Crystallography)

Journal Articles

Defect characterization in compositionally graded InGaAs layers on GaAs (001) grown by MBE

Sasaki, Takuo; Norman, A. G.*; Romero, M. J.*; Al-Jassim, M. M.*; Takahashi, Masamitsu; Kojima, Nobuaki*; Oshita, Yoshio*; Yamaguchi, Masafumi*

Physica Status Solidi (C), 10(11), p.1640 - 1643, 2013/11

 Times Cited Count:3 Percentile:81.12

Journal Articles

Real-time observation of crystallographic tilting InGaAs layers on GaAs offcut substrates

Nishi, Toshiaki*; Sasaki, Takuo; Ikeda, Kazuma*; Suzuki, Hidetoshi*; Takahashi, Masamitsu; Shimomura, Kenichi*; Kojima, Nobuaki*; Oshita, Yoshio*; Yamaguchi, Masafumi*

AIP Conference Proceedings 1556, p.14 - 17, 2013/09

 Times Cited Count:0 Percentile:0.01

Journal Articles

Numerical estimation of Ohmic loss of high power wideband diplexer for ECCD system

Atsumi, Kohei*; Yamaguchi, Tomoki*; Nagashima, Koji*; Saigusa, Mikio*; Fukunari, Masafumi*; Oda, Yasuhisa; Sakamoto, Keishi

Plasma and Fusion Research (Internet), 8(Sp.1), p.2405077_1 - 2405077_4, 2013/06

Journal Articles

Observation of in-plane asymmetric strain relaxation during crystal growth and growth interruption in InGaAs/GaAs(001)

Sasaki, Takuo*; Shimomura, Kenichi*; Suzuki, Hidetoshi*; Takahashi, Masamitsu; Kamiya, Itaru*; Oshita, Yoshio*; Yamaguchi, Masafumi*

Japanese Journal of Applied Physics, 51(2), p.02BP01_1 - 02BP01_3, 2012/02

 Times Cited Count:2 Percentile:10.01(Physics, Applied)

Journal Articles

Real-time structural analysis of compositionally graded InGaAs/GaAs(001) layers

Sasaki, Takuo*; Suzuki, Hidetoshi*; Inagaki, Makoto*; Ikeda, Kazuma*; Shimomura, Kenichi*; Takahashi, Masamitsu; Kozu, Miwa*; Hu, W.; Kamiya, Itaru*; Oshita, Yoshio*; et al.

IEEE Journal of Photovoltaics, 2(1), p.35 - 40, 2012/01

 Times Cited Count:5 Percentile:25.16(Energy & Fuels)

Journal Articles

X-ray reciprocal space mapping of dislocation-mediated strain relaxation during InGaAs/GaAs(001) epitaxial growth

Sasaki, Takuo*; Suzuki, Hidetoshi*; Takahashi, Masamitsu; Oshita, Yoshio*; Kamiya, Itaru*; Yamaguchi, Masafumi*

Journal of Applied Physics, 110(11), p.113502_1 - 113502_7, 2011/12

 Times Cited Count:11 Percentile:47.47(Physics, Applied)

Journal Articles

Growth temperature dependence of strain relaxation during InGaAs/GaAs(0 0 1) heteroepitaxy

Sasaki, Takuo*; Suzuki, Hidetoshi*; Sai, Akihisa*; Takahashi, Masamitsu; Fujikawa, Seiji; Kamiya, Itaru*; Oshita, Yoshio*; Yamaguchi, Masafumi*

Journal of Crystal Growth, 323(1), p.13 - 16, 2011/05

 Times Cited Count:17 Percentile:82.2(Crystallography)

Growth temperature dependence of strain relaxation during In$$_{0.12}]$$Ga$$_{0.88}$$As/GaAs(001) molecular beam epitaxy was studied by in situ X-ray reciprocal space mapping. Evolution of the residual strain and crystal quality for the InGaAs film was obtained as a function of film thickness at growth temperatures of 420, 445 and 477 $$^{circ}$$C. In the early stages of strain relaxation, it was found that evolution of the residual strain and crystal quality was dependent on the growth temperature. In order to discuss this observation quantitatively, the strain relaxation model was proposed based on the Dodson-Tsao kinetic model, and its validity was demonstrated by good agreement with the experimental residual strain. Additionally, rate coefficients reflecting dislocation motions during strain relaxation were obtained as a function of growth temperature and strain relaxation was discussed in terms of the thermally active dislocation motion.

Journal Articles

Theoretical optimization of base doping concentration for radiation resistance of InGaP subcells of InGaP/GaAs/Ge based on minority-carrier lifetime

Elfiky, D.*; Yamaguchi, Masafumi*; Sasaki, Takuo*; Takamoto, Tatsuya*; Morioka, Chiharu*; Imaizumi, Mitsuru*; Oshima, Takeshi; Sato, Shinichiro; Elnawawy, M.*; Eldesoky, T.*; et al.

Japanese Journal of Applied Physics, 49(12), p.121201_1 - 121201_7, 2010/12

 Times Cited Count:10 Percentile:43.19(Physics, Applied)

One of the fundamental objectives for research and development of space solar cells is to improve their radiation resistance. InGaP solar cells with low base carrier concentrations under low-energy proton irradiations have shown high radiation resistances. In this study, an analytical model for low-energy proton radiation damage to InGaP subcells based on a fundamental approach for radiative and nonradiative recombinations has been proposed. The radiation resistance of InGaP subcells as a function of base carrier concentration has been analyzed by using the radiative recombination lifetime and damage coefficient K for the minority-carrier lifetime of InGaP. Numerical analysis shows that an InGaP solar cell with a lower base carrier concentration is more radiation-resistant. Satisfactory agreements between analytical and experimental results have been obtained, and these results show the validity of the analytical procedure. The damage coefficients for minority-carrier diffusion length and carrier removal rate with low-energy proton irradiations have been observed to be dependent on carrier concentration through this study. As physical mechanisms behind the difference observed between the radiation-resistant properties of various base doping concentrations, two mechanisms, namely, the effect of a depletion layer as a carrier collection layer and generation of the impurity-related complex defects due to low-energy protons stopping within the active region, have been proposed.

Journal Articles

Effect of base doping concentration on radiation-resistance for GaAs sub-cells in InGaP/GaAs/Ge

Elfiky, D.*; Yamaguchi, Masafumi*; Sasaki, Takuo*; Takamoto, Tatsuya*; Morioka, Chiharu*; Imaizumi, Mitsuru*; Oshima, Takeshi; Sato, Shinichiro; Elnawawy, M.*; Eldesoky, T.*; et al.

Japanese Journal of Applied Physics, 49(12), p.121202_1 - 121202_5, 2010/12

 Times Cited Count:6 Percentile:29.58(Physics, Applied)

GaAs solar cells with the lower base carrier concentration under low energy proton irradiations had shown experimentally the better radiation-resistance. Analytical model based on fundamental approach for radiative and non-radiative recombination has been proposed for radiation damage in GaAs sub-cells. The radiation resistance of GaAs sub-cells as a function of base carrier concentration has been analyzed by using radiative recombination lifetime and damage coefficient for minority carrier lifetime. Numerical analysis shows good agreement with experimental results. The effect of carrier concentration upon the change of damage constant and carrier removal rate have been studied.

Journal Articles

Real-time observation of anisotropic strain relaxation by three-dimensional reciprocal space mapping during InGaAs/GaAs(001) growth

Suzuki, Hidetoshi*; Sasaki, Takuo*; Sai, Akihisa*; Oshita, Yoshio*; Kamiya, Itaru*; Yamaguchi, Masafumi*; Takahashi, Masamitsu; Fujikawa, Seiji

Applied Physics Letters, 97(4), p.041906_1 - 041906_3, 2010/07

 Times Cited Count:30 Percentile:76.37(Physics, Applied)

Journal Articles

Study the effects of proton irradiation on GaAs/Ge solar cells

Elfiky, D.*; Yamaguchi, Masafumi*; Sasaki, Takuo*; Takamoto, Tatsuya*; Morioka, Chiharu*; Imaizumi, Mitsuru*; Oshima, Takeshi; Sato, Shinichiro; Elnawawy, M.*; Eldesuky, T.*; et al.

Proceedings of 35th IEEE Photovoltaic Specialists Conference (PVSC-35) (CD-ROM), p.002528 - 002532, 2010/06

 Times Cited Count:1 Percentile:61.53

Proton energy dependence of radiation damage to GaAs/Ge solar cells irradiated with protons with various energies (50 keV, 200 keV, 1 MeV and 9.5 MeV) were analyzed by using PC1D simulation together with SRIM simulations to investigate their electrical properties. The degradation of the open-circuit voltage is highest for 50 keV irradiation and lowest for 9.5 MeV irradiation. According to SRIM simulations the above changes in electrical properties are mainly related to damage in different regions of the solar sells.

Journal Articles

In situ study of strain relaxation mechanisms during lattice-mismatched InGaAs/GaAs growth by X-ray reciprocal space mapping

Sasaki, Takuo*; Suzuki, Hidetoshi*; Sai, Akihisa*; Takahashi, Masamitsu; Fujikawa, Seiji; Oshita, Yoshio*; Yamaguchi, Masafumi*

Materials Research Society Symposium Proceedings, Vol.1268, 6 Pages, 2010/05

 Times Cited Count:0 Percentile:0.01

Journal Articles

${it In situ}$ real-time X-Ray reciprocal space mapping during InGaAs/GaAs growth for understanding strain relaxation mechanisms

Sasaki, Takuo*; Suzuki, Hidetoshi*; Sai, Akihisa*; Lee, J.-H.*; Takahashi, Masamitsu; Fujikawa, Seiji; Arafune, Koji*; Kamiya, Itaru*; Oshita, Yoshio*; Yamaguchi, Masafumi*

Applied Physics Express, 2, p.085501_1 - 085501_3, 2009/07

 Times Cited Count:34 Percentile:78.52(Physics, Applied)

Journal Articles

The H-Invitational Database (H-InvDB); A Comprehensive annotation resource for human genes and transcripts

Yamasaki, Chisato*; Murakami, Katsuhiko*; Fujii, Yasuyuki*; Sato, Yoshiharu*; Harada, Erimi*; Takeda, Junichi*; Taniya, Takayuki*; Sakate, Ryuichi*; Kikugawa, Shingo*; Shimada, Makoto*; et al.

Nucleic Acids Research, 36(Database), p.D793 - D799, 2008/01

 Times Cited Count:51 Percentile:74.53(Biochemistry & Molecular Biology)

Here we report the new features and improvements in our latest release of the H-Invitational Database, a comprehensive annotation resource for human genes and transcripts. H-InvDB, originally developed as an integrated database of the human transcriptome based on extensive annotation of large sets of fulllength cDNA (FLcDNA) clones, now provides annotation for 120 558 human mRNAs extracted from the International Nucleotide Sequence Databases (INSD), in addition to 54 978 human FLcDNAs, in the latest release H-InvDB. We mapped those human transcripts onto the human genome sequences (NCBI build 36.1) and determined 34 699 human gene clusters, which could define 34 057 protein-coding and 642 non-protein-coding loci; 858 transcribed loci overlapped with predicted pseudogenes.

Journal Articles

Growth of ferroelectric bismuth lanthanum nickel titanate thin films by RF magnetron sputtering

Kobune, Masafumi*; Fukushima, Koji*; Yamaji, Toru*; Tada, Hideto*; Yazawa, Tetsuo*; Fujisawa, Hironori*; Shimizu, Masaru*; Nishihata, Yasuo; Matsumura, Daiju; Mizuki, Junichiro; et al.

Journal of Applied Physics, 101(7), p.074110_1 - 074110_6, 2007/04

 Times Cited Count:8 Percentile:35.04(Physics, Applied)

no abstracts in English

Journal Articles

Electron radiation induced defects in lattice-mismatched solar cells

Sasaki, Takuo*; Ekins-Daukes, N. J.*; Lee, H. S.*; Takamoto, Tatsuya*; Imaizumi, Mitsuru*; Oshima, Takeshi; Ito, Hisayoshi; Yamaguchi, Masafumi*

JAEA-Review 2006-042, JAEA Takasaki Annual Report 2005, P. 7, 2007/02

no abstracts in English

Journal Articles

Alternative splicing in human transcriptome; Functional and structural influence on proteins

Yura, Kei; Shionyu, Masafumi*; Hagino, Kei*; Hijikata, Atsushi*; Hirashima, Yoshinori*; Nakahara, Taku*; Eguchi, Tatsuya*; Shinoda, Kazuki*; Yamaguchi, Akihiro*; Takahashi, Kenichi*; et al.

Gene, 380(2), p.63 - 71, 2006/10

 Times Cited Count:52 Percentile:73.2(Genetics & Heredity)

Alternative splicing is a molecular mechanism that produces multiple proteins from a single gene, and is thought to produce variety in proteins translated from a limited number of genes. Here we analyzed how alternative splicing produced variety in protein structure and function, by using human full-length cDNAs, on the assumption that all of the alternatively spliced mRNAs were translated to proteins. We found that the length of alternatively spliced amino acid sequences, in most cases, fell into a size shorter than that of average protein domain. We evaluated comprehensively the presumptive three-dimensional structures of the alternatively spliced products to assess the impact of alternative splicing on gene function. We found that more than half of the products encoded proteins which were involved in signal transduction, transcription and translation, and more than half of alternatively spliced regions comprised interaction sites between proteins and their binding partners, including substrates, DNA/RNA, and other proteins. Intriguingly, 67% of the alternatively spliced isoforms showed significant alterations to regions of the protein structural core, which likely resulted in large conformational change. Based on those findings, we speculate that there are a large number of cases that alternative splicing modulates protein networks through significant alteration in protein conformation.

Journal Articles

Electron radiation-induced defects in lattice mismatched InGaAs solar cells

Sasaki, Takuo*; Takamoto, Tatsuya*; Imaizumi, Mitsuru*; Oshima, Takeshi; Ito, Hisayoshi; Yamaguchi, Masafumi*

Proceedings of 7th International Workshop on Radiation Effects on Semiconductor Devices for Space Application (RASEDA-7), p.165 - 168, 2006/10

no abstracts in English

63 (Records 1-20 displayed on this page)