Harjo, S.; Kubota, Satoru*; Gong, W.*; Kawasaki, Takuro; Gao, S.*
Acta Materialia, 196, p.584 - 594, 2020/09
Yamaguchi, Hisato*; Ogawa, Shuichi*; Watanabe, Daiki*; Hozumi, Hideaki*; Gao, Y.*; Eda, Goki*; Mattevi, C.*; Fujita, Takeshi*; Yoshigoe, Akitaka; Ishizuka, Shinji*; et al.
Physica Status Solidi (A), 213(9), p.2380 - 2386, 2016/09
We report valence-band electronic structure evolution of graphene oxide (GO) upon its thermal reduction. The degree of oxygen functionalization was controlled by annealing temperature, and an electronic structure evolution was monitored using real-time ultraviolet photoelectron spectroscopy. We observed a drastic increase in the density of states around the Fermi level upon thermal annealing at 600C. The result indicates that while there is an apparent bandgap for GO prior to a thermal reduction, the gap closes after an annealing around that temperature. This trend of bandgap closure was correlated with the electrical, chemical, and structural properties to determine a set of GO material properties that is optimal for optoelectronics. The results revealed that annealing at a temperature of 500C leads to the desired properties, demonstrated by a uniform and an order of magnitude enhanced photocurrent map of an individual GO sheet compared to an as-synthesized counterpart.
Tremsin, A. S.*; Gao, Y.*; Dial, L. C.*; Grazzi, F.*; Shinohara, Takenao
Science and Technology of Advanced Materials, 17(1), p.324 - 336, 2016/07
Schaffer, M. J.*; Snipes, J. A.*; Gohil, P.*; de Vries, P.*; Evans, T. E.*; Fenstermacher, M. E.*; Gao, X.*; Garofalo, A. M.*; Gates, D. A.*; Greenfield, C. M.*; et al.
Nuclear Fusion, 51(10), p.103028_1 - 103028_11, 2011/10
Experiments at DIII-D investigated the effects of ferromagnetic error fields similar to those expected from proposed ITER Test Blanket Modules (TBMs). Studied were effects on: plasma rotation and locking; confinement; L-H transition; edge localized mode (ELM) suppression by resonant magnetic perturbations; ELMs and the H-mode pedestal; energetic particle losses; and more. The experiments used a 3-coil mock-up of 2 magnetized ITER TBMs in one ITER equatorial port. The experiments did not reveal any effect likely to preclude ITER operations with a TBM-like error field. The largest effect was slowed plasma toroidal rotation v across the entire radial profile by as much as via non-resonant braking. Changes to global , and were 3 times smaller. These effects are stronger at higher and lower . Other effects were smaller.
Tanaka, Tadao; Nagao, Seiya; Sakamoto, Yoshiaki; Onuki, Toshihiko; S.Ni*; *
Journal of Nuclear Science and Technology, 34(8), p.829 - 834, 1997/08
no abstracts in English
Tanaka, Tadao; Nagao, Seiya; Sakamoto, Yoshiaki; Onuki, Toshihiko; S.Ni*;
Hoshasei Haikibutsu Kenkyu, 3(1), p.41 - 47, 1996/08
no abstracts in English
Snipes, J. A.*; Schaffer, M. J.*; Gohil, P.*; de Vries, P.*; Fenstermacher, M. E.*; Evans, T. E.*; Gao, X. M.*; Garofalo, A.*; Gates, D. A.*; Greenfield, C. M.*; et al.
no journal, ,
A series of experiments was performed on DIII-D to mock-up the field that will be induced in a pair of ferromagnetic Test Blanket Modules (TBMs) in ITER to determine the effects of such error fields on plasma operation and performance. A set of coils producing both poloidal and toroidal fields was placed inside a re-entrant horizontal port close to the plasma. The coils produce a localized ripple due to the toroidal field (TF) + TBM up to 5.7%, which is more than four times that expected from a pair of representative 1.3 ton TBMs in ITER. The experiments show that the reduction in the toroidal rotation is sensitive to the ripple. On the other hand, the confinement is reduced by up to 15-18% for local ripple 3% but is hardly affected at 1.7% local ripple.
Sanial, V.*; Buesseler, K. O.*; Charette, M.*; Casacuberta, N.*; Castrillejo, M.*; Henderson, P.*; Juan Diaz, X.*; Kanda, Jota*; Masque, P.*; Nagao, Seiya*; et al.
no journal, ,
Radiocesium activities in the coastal ocean off Fukushima dropped by orders of magnitude within one year after the accident of Fukushima Dai-ichi Nuclear Power Plant (FDNPP), but have remained relatively constant over the past 5 years exceeding background values. We investigated distribution of radiocesium in surface seawater and submarine groundwater along the Fukushima coast in October 2015. Our highest radiocesium activities were not found in the ocean, but in groundwater samples underlying coastal beaches 35 km south from the FDNPP. This may be due to sorption of the extremely contaminated waters on to beach sands/clays early after the accident and subsequent desorption back in to the ocean. Submarine groundwater discharge, which is widely recognized to be an important vector for the transport of chemicals from land to ocean, is thus a non-negligible path for transport of Fukushima-derived radionuclides to the ocean.