Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Ogawa, Fumio*; Nakayama, Yuta*; Hiyoshi, Noritake*; Hashidate, Ryuta; Wakai, Takashi; Ito, Takamoto*
Transactions of the Indian National Academy of Engineering (Internet), 7(2), p.549 - 564, 2022/06
The strain energy-based life evaluation method of Mod. 9Cr-1Mo steel under non-proportional multiaxial creep-fatigue loading is proposed. Inelastic strain energy densities were calculated as the areas inside the hysteresis loops. The effect of mean-stress has been experimentally considered and the relationship between inelastic strain energy densities and creep-fatigue lives was investigated. It was found from the investigation of hysteresis loops, the decrease in maximum stress leads to prolonged failure life, while stress relaxation during strain holding causes strength reduction. The correction method of inelastic strain energy density was proposed considering the effect of maximum stress in hysteresis loop and minimum stress during strain holding, and strain energy densities for uniaxial and non-proportional multiaxial loading were obtained. Based on these results, the mechanisms governing creep-fatigue lives under non-proportional multiaxial loading have been discussed.
Nakayama, Yuta*; Ogawa, Fumio*; Hiyoshi, Noritake*; Hashidate, Ryuta; Wakai, Takashi; Ito, Takamoto*
ISIJ International, 61(8), p.2299 - 2304, 2021/08
Times Cited Count：4 Percentile：33.99(Metallurgy & Metallurgical Engineering)This study discusses the creep-fatigue strength for Mod.9Cr-1Mo steel at a high temperature under multiaxial loading. A low-cycle fatigue tests in various strain waveforms were performed with a hollow cylindrical specimen. The low cycle fatigue test was conducted under a proportional loading with a fixed axial strain and a non-proportional loading with a 90-degree phase difference between axial and shear strains. The low cycle fatigue tests at different strain rates and the creep-fatigue tests at different holding times were also conducted to discuss the effects of stress relaxation and strain holding on the failure life. In this study, two types of multiaxial creep-fatigue life evaluation methods were proposed: the first method is to calculate the strain range using Manson's universal slope method with considering a non-proportional loading factor and creep damage; the second method is to calculate the fatigue damage by considering the non-proportional loading factor using the linear damage law and to calculate the creep damage from the improved ductility exhaustion law. The accuracy of the evaluation methods is much better than that of the methods used in the evaluation of actual machines such as time fraction rule.
Kanayama, Hideyuki*; Hiyoshi, Noritake*; Ogawa, Fumio*; Kawabata, Mie*; Ito, Takamoto*; Wakai, Takashi
Zairyo, 68(5), p.421 - 428, 2019/05
This study presents creep damage assessment method for Mod. 9Cr-1Mo steel by sampling creep testing with thin plate specimen. Tensile creep rupture tests were performed using three different sizes of specimen under two different test environments to verify the creep testing with the thin plate specimen. Time to rupture of Mod. 9Cr-1Mo steel using three different sizes were almost same. In addition, there was no effect of environment on time to rupture. Pre-damaged thin plate specimens were machined from a bulk specimen's gage section that pre-damage test was performed with. Pre-damage based on life fraction rule were 8%, 16% and 25%. No effect of the process of machining pre-damaged specimen on time to rupture was confirmed by verification tests in same test condition as pre-damage test. Stress acceleration creep rupture tests were performed to estimate creep damage assessment. Creep damage assessment by stress acceleration creep rupture tests was sufficiently accurate estimate. Creep damage assessments by Vickers hardness and lath width were compared with the assessment by stress acceleration creep rupture tests to study applicability of these methods.
Kanayama, Hideyuki; Hiyoshi, Noritake*; Ito, Takamoto*; Ogawa, Fumio*; Wakai, Takashi
Zairyo, 66(2), p.86 - 92, 2017/02
This study presents creep characteristics of Mod. 9Cr-1Mo steel with various sized specimens and environment. Creep tests were performed using three different sizes of specimen and three different type of testing environment. Specimens are a bulk specimen which has 6mm diameter and 30mm gage length, a miniature specimen which has 2mm diameter and 10mm gage length and a thin plate specimen which has 0.76mm thickness, 1.5mm width and 7.62mm gage length. Three different type of testing environment are air, 99.99% Ar gas and vacuum. In the same environmental condition, there was no effect of specimen size on time to rupture. Time to rupture of Mod. 9Cr-1Mo steel in Ar gas was shorter than that in air and vacuum. Oxide thickness is not dominant factor in time to rupture. Fracture mode at specimen surface in Ar gas might be dominant factor in shorter time to rupture. Effect of specimen size and environment on creep strength of Mod. 9Cr-1Mo steel was evaluated on the basis of thinning.
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
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
Yamaguchi, Masafumi*; Ekins-Daukes, N. J.*; Lee, H. S.*; Sumita, Taishi*; Imaizumi, Mitsuru*; Takamoto, Tatsuya*; Agui, Takaaki*; Kaneiwa, Minoru*; Kamimura, Kunio*; Oshima, Takeshi; et al.
Proceedings of 2006 IEEE 4th World Conference on Photovoltaic Energy Conversion (WCPEC-4) (CD-ROM), p.1789 - 1792, 2006/05
no abstracts in English
AlInGaP solar cellsLee, H. S.*; Yamaguchi, Masafumi*; Ekins-Daukes, N. J.*; Khan, A.*; Takamoto, Tatsuya*; Imaizumi, Mitsuru*; Oshima, Takeshi; Ito, Hisayoshi
Proceedings of 2006 IEEE 4th World Conference on Photovoltaic Energy Conversion (WCPEC-4) (CD-ROM), p.1826 - 1829, 2006/05
no abstracts in English
/p-AlInGaP solar cellsLee, H. S.*; Yamaguchi, Masafumi*; Ekins-Daukes, N. J.*; Khan, A.*; Takamoto, Tatsuya*; Imaizumi, Mitsuru*; Oshima, Takeshi; Ito, Hisayoshi
Physica B; Condensed Matter, 376-377, p.564 - 567, 2006/04
Times Cited Count：2 Percentile：12.58(Physics, Condensed Matter)no abstracts in English
Lee, H. S.*; Yamaguchi, Masafumi*; Ekins-Daukes, N. J.*; Khan, A.*; Takamoto, Tatsuya*; Agui, Takaaki*; Kamimura, Kunio*; Kaneiwa, Minoru*; Imaizumi, Mitsuru*; Oshima, Takeshi; et al.
Journal of Applied Physics, 98(9), p.093701_1 - 093701_4, 2005/11
Times Cited Count：12 Percentile：43.27(Physics, Applied)no abstracts in English
Hattori, Shuji*; Ito, Takamoto*; Watashi, Katsumi; Hashimoto, Takashi
JNC TY4400 2005-003, 82 Pages, 2005/09
no abstracts in English
Lee, H. S.*; Ekins-Daukes, N. J.*; Sasaki, Takuo*; Yamaguchi, Masafumi*; Khan, A.*; Takamoto, Tatsuya*; Agui, Takaaki*; Kamimura, Kunio*; Kaneiwa, Minoru*; Imaizumi, Mitsuru*; et al.
Proceedings of 31st IEEE Photovoltaic Specialists Conference and Exhibition (PVSC-31), p.556 - 558, 2005/00
no abstracts in English
Ekins-Daukes, N. J.*; Arafune, Koji*; Lee, H. S.*; Sasaki, Takuo*; Yamaguchi, Masafumi*; Khan, A.*; Takamoto, Tatsuya*; Agui, Takaaki*; Kamimura, Kunio*; Kaneiwa, Minoru*; et al.
Proceedings of 31st IEEE Photovoltaic Specialists Conference and Exhibition (PVSC-31), p.683 - 686, 2005/00
no abstracts in English
/p InGaP solar cellDharmarasu, N.*; Yamaguchi, Masafumi*; Khan, A.*; Takamoto, Tatsuya*; Oshima, Takeshi; Ito, Hisayoshi; Imaizumi, Mitsuru*; Matsuda, Sumio*
Solar Energy Materials and Solar Cells, 75(1-2), p.327 - 333, 2003/01
Times Cited Count：3 Percentile：30.01(Energy & Fuels)n/p InGaP junctions were irradiated with 100keV-protons, and the effect on their electrical properties were studied using C-V and DLTS methods.The n/p InGaP junctions were fabricated by MOCVD method.They were irradiated up to 1E12 /cm
at RT. The carrier removal rate was estimated to be 6.1E4 cm
from the fluence dependence of carrier concentration. H1 peaks which were observed at 400 K in DLTS measurements were found after irradiation.It was concluded that H1 peaks relates residual defects which act as carrier removal centers.
Oshima, Takeshi; Imaizumi, Mitsuru*; Takamoto, Tatsuya*; Sumita, Taishi*; Oi, Akihiko; Kawakita, Shiro*; Ito, Hisayoshi; Matsuda, Sumio*
Proceedings of 5th International Workshop on Radiation Effects on Semiconductor Devices for Space Applications, p.113 - 116, 2002/10
The effects on proton and electron irradiateions of the characteristics of InGaP/GaAs/Ge triple junction designed for terrestrial application were studied. The solar cells used in this study has a 1% In-contained GaAs middle sub-cell, and their efficiency is more than 30 % under AM1.5, which is the highest efficiency of all solar cells in the world.As the results of 1MeV-electron and 10 MeV-proton irradiation, terrestrial triple-junction sole cells were found to have the same radiation resistance as space single junction GaAs solar cells, although terrestrial triple-junction solar cells is not stronger than space triple-junction solar cells made in USA. As the result of proton energy dependence of the electrical characteristics and quantum efficiency, the strong degradation of the GaAs middle cell was observed.
-InGaP space solar cellsDharmarasu, N.*; Yamaguchi, Masafumi*; Bourgoin, J. C.*; Takamoto, Tatsuya*; Oshima, Takeshi; Ito, Hisayoshi; Imaizumi, Mitsuru*; Matsuda, Sumio*
Applied Physics Letters, 81(1), p.64 - 66, 2002/07
Times Cited Count：17 Percentile：55.85(Physics, Applied)We studied the properties of observed defects in n/p-InGaP solar cells created by irradiation of protons with different energies.Three majority (hole) and a minority-carrier traps, labeled respectively as HP1 (E
+0.90
0.05eV), HP2 (E+0.730.05eV), H2 (E +0.55eV),and EP1 (E
0.54eV),were identified using deep level transient spectroscopy. All majority-carrier traps were found to act as recombination centers. While the H2 traps present in the proton-irradiated p-InGaP was found to anneal out by minority-carrier injection, the other traps were not.
InGaP solar CellsDharmarasu, N.*; Khan, A.*; Yamaguchi, Masafumi*; Takamoto, Tatsuya*; Oshima, Takeshi; Ito, Hisayoshi; Imaizumi, Mitsuru*; Matsuda, Sumio*
Journal of Applied Physics, 91(5), p.3306 - 3311, 2002/03
Times Cited Count：25 Percentile：66.97(Physics, Applied)3MeV proton irradiation effects on InGaP single junction and InGaP/GaAs two junction cells were studied. The degradation of electrocal properties for InGaP cells was smaller than that for InGaP/GaAs cells. The results of the measurement of spectral response showed the large degradation in long wavelength. This indicates that GaAs cell degrades. The Damage coefficient of minority carrier diffusion length was estimated to be 7.9
10
for InGaP and 1.610
for GaAs. These values of the damage coefficient for InGaP and GaAs are 580 times and 280 times larger than those for InGaP and GaAs irradiated with 1MeV electrons.
/p InGaP solar cellDharmarasu, N.*; Yamaguchi, Masafumi*; Khan, K.*; Takamoto, Tatsuya*; Oshima, Takeshi; Ito, Hisayoshi; Imaizumi, Mitsuru*; Matsuda, Sumio*
Physica B; Condensed Matter, 308-310, p.1181 - 1184, 2001/12
Times Cited Count：7 Percentile：41.38(Physics, Condensed Matter)Carrier concentration and defects in n+/p InGaP irradiated with 100keV-protons (1E10, 5E12 /cm2) were studied.As a result of C-V measurements, the carrier removal rate was estimated to be 6.1E4 /cm2 which was extremely high as compared to 1MeV-electron irradiation case (0.93 /cm). H1 peak whose energy corresponds to Ev+0.90V was obtained from DLTS measurements. This suggests that carrier removal rate in proton-irradiated ones is much higher than that in electron-irradiated ones due to the generation of the defects (H1 peak) which act as majority carrier traps.
Dharmarasu, N.*; Yamaguchi, Masafumi*; Khan, A.*; Yamada, Takashi*; Tanabe, Tatsuya*; Takagishi, Shigenori*; Takamoto, Tatsuya*; Oshima, Takeshi; Ito, Hisayoshi; Imaizumi, Mitsuru*; et al.
Applied Physics Letters, 79(15), p.2399 - 2401, 2001/10
Times Cited Count：75 Percentile：90.93(Physics, Applied)The radiation response of 3MeV proton-irradiated InGaP, InGaAsP, and InGaAs solar cells was measured and analyzed in comparison with those of InP and GaAs. The degradation of the minority-carrier diffusion length was estimated from the spectral response. The damage coefficient K
for 3MeV proton-irradiated InGaP, InGaAsP and InGaAs was also determined. The radiation resistance increases with increase in the function of In-P bonds in those materials. Minority-carrier injection under forward bias is found to cause partial recovery of the degradation on irradiated InGaP and InGaAsP cells.
Takeda, Toshikazu*; Ito, Noboru*; Kugo, Teruhiko*; Takamoto, Masanori*; Aoki, Shigeaki*; Kawagoe, Yoshihiro*; Sengoku, Katsuhisa*; Tanaka, Motonari*; Yoshimura, Akira*; Tamitani, Masashi*; et al.
PNC TJ2605 89-001, 251 Pages, 1989/03
no abstracts in English
