Matsuda, Asahi*; Takahashi, Satoru*; Kawabata, Kuniaki; Oda, Shoji*; Kaneko, Shunichi*
Denki Gakkai Rombunshi, D, 139(4), p.424 - 432, 2019/04
Teraoka, Yuden; Jinno, Muneaki*; Takaoka, Tsuyoshi*; Harries, J.; Okada, Ryuta; Iwai, Yutaro*; Yoshigoe, Akitaka; Komeda, Tadahiro*
Denki Gakkai Rombunshi, C, 134(4), p.524 - 525, 2014/04
Teraoka, Yuden; Tode, Mayumi*; Harries, J.; Yoshigoe, Akitaka
Denki Gakkai Rombunshi, C, 134(4), p.473 - 478, 2014/04
Imai, Suguru*; Taguchi, Kenji*; Kashiwa, Tatsuya*; Kitazawa, Toshihide*; Kato, Yoshiyuki; Segawa, Tomoomi; Suzuki, Masahiro
Denki Gakkai Rombunshi, A, 133(5), p.271 - 272, 2013/05
As a part of the nuclear fuel cycle in Japan, the mixed oxide (MOX) fuels are produced through the microwave heating of the Pu/U mixed nitrate solution obtained from spent fuels. In this work, we investigate the effect of a spacer between the bottom of cavity and solution dish in microwave oven cavity to heat unifomly Pu/U mixed nitrate solution for making MOX fuels. As a result, we show the effectiveness of inserting the spacer for a uniform heating of the solution by evaluating the top-to-bottom ratio.
Inoue, Keisuke; Teraoka, Yuden
Denki Gakkai Rombunshi, C, 130(10), p.1817 - 1818, 2010/10
The effective attenuation length (EAL) is a necessary parameter to estimate the thickness of SiO overlayer by X-ray photoemission spectroscopy (XPS). Inelastic mean free path (IMFP) is often used instead of EAL because EAL is scarcely known. EAL values were determined experimentally in the photon energy region from 480 eV to 800 eV using synchrotron radiation photoemission spectroscopy. Although EALs estimated are different from calculated IMFPs, EALs, estimated without suboxides, are mostly close to theoretically-calculated IMFPs.
Tode, Mayumi; Harries, J.; Teraoka, Yuden; Yoshigoe, Akitaka
Denki Gakkai Rombunshi, C, 130(10), p.1819 - 1820, 2010/10
In order to study the thermal degradation process of the hydrogen storage materials surface layer and the thermal desorption of hydrogen property, we have used high-resolution synchrotron radiation X-ray photoelectron spectroscopy. The experiments were performed at the JAEA soft X-ray beamline BL23SU at SPring-8, using the "SUREAC2000" surface reaction analysis apparatus. Spectra were recorded for two samples (VCrTi) covered with native oxide layers, one of which was implanted with deuterium ions. For the un-implanted sample, the oxide layer changes dramatically between 373 K and 473 K, for the deuterium-implanted sample, the change occurs between 473 K and 573 K. The implantation of deuterium leads to a stabilization (of approximately 100 K) of the surface oxide layer.
Kado, Masataka; Ishino, Masahiko; Tamotsu, Satoshi*; Yasuda, Keiko*; Kishimoto, Maki; Nishikino, Masaharu; Kinjo, Yasuhito*; Shinohara, Kunio*
Denki Gakkai Rombunshi, C, 130(10), p.1774 - 1778, 2010/10
Actin filaments in Leydig cells from mouse testes have been observed with a contact-type soft X-ray microscope with laser plasma X-ray source. The Leydig cells were fixed with paraformaldehyde, stained with Phalloidin, and observed with a confocal laser microscope prior to the observation with X-ray microscope. Obtained images by both of the confocal laser microscopy and the X-ray microscopy were directly compared and revealed that not only position of actin filaments but also the shapes can be identified each other. The actin filaments in the X-ray images were clearly recognized and their structures were obtained in more detail compared to those in the confocal laser microscope images.
Daido, Hiroyuki; Pirozhkov, A. S.; Nishiuchi, Mamiko
Denki Gakkai Rombunshi, C, 130(10), p.1706 - 1710, 2010/10
no abstracts in English
Sato, Katsutoshi; Nishikino, Masaharu; Numasaki, Hodaka*; Kawachi, Tetsuya; Teshima, Teruki*; Nishimura, Hiroaki*
Denki Gakkai Rombunshi, C, 130(10), p.1800 - 1805, 2010/10
no abstracts in English
Hashinokuchi, Michihiro*; Sumimoto, Yuichi*; Tode, Mayumi; Harries, J.; Okada, Michio*; Teraoka, Yuden; Kasai, Toshio*
Denki Gakkai Rombunshi, C, 130(10), p.1723 - 1729, 2010/10
The oxidation processes on a TiAl surface induced by a hyperthermal O molecular beam (HOMB) with a translational energy of 2.2 eV was studied by X-ray photoemission spectroscopy in conjunction with synchrotron radiation. At a surface temperature of 300 K, the simultaneous growth of Al and Ti oxides accompanied with the segregation of AlO near the surface was observed. The efficiency of oxidation for the HOMB incidence was smaller than that for O backfilling (25 meV). Furthermore, the chemical compositions of oxide species (AlO, TiO, TiO) on the TiAl surface were independent of the translational energy of incident O molecule. The present results suggest that the oxidation on TiAl surface proceeds via precursor molecular states.
Denki Gakkai Rombunshi, A, 129(9), p.585 - 588, 2009/09
To evaluate a bootstrap-current-profile quickly, a simple method has been developed with a novel approximation. This results in that all of the neoclassical diffusion coefficients for the gradient become the polynominals only in variables of inverse aspect-ratio, , effective charge, Z and collisionality, , in the whole range of variables. The resultant current profile is well reproduced from ITER benchmark with transport code including the case with internal-transport-barrier. This method is applied to a commercial reactor, VECTOR, low-aspect-ratio tokamak reactor. The fraction of bootstrap-current, I/I, are evaluated as: 55%, 60% and 100% for the normal-shear, weakly-reversed-shear and strongly-reversed-shear (with current-hole) plasmas, respectively.
Tani, Keiji*; Nishio, Satoshi; Tobita, Kenji; Tsutsui, Hiroaki*; Mimata, Hideyuki*; Iio, Shunji*; Aoki, Takayuki*
Denki Gakkai Rombunshi, A, 129(9), p.569 - 574, 2009/09
Studies on the loss of fusion produced alpha particles enhanced by toroidal field (TF) ripple in a low-aspect-ratio tokamak reactor (VECTOR) have been made by using an orbit-following Monte-Carlo code. In actual TF coil systems, the ripple loss of alpha particles is strongly reduced as the aspect ratio becomes low (the power loss is proportional to A for A more than 2.5) and the reduction of the number of TF coils results in a large amount of ripple losses even in a low-aspect-ratio tokamak.
Teraoka, Yuden; Yoshigoe, Akitaka
Denki Gakkai Rombunshi, C, 129(2), p.294 - 295, 2009/02
The Al(111) surface has been directly nitrided by supersonic N molecular beams at 473 K. A translational kinetic energy threshold of the nitridation was 1.8 eV. A nitrogen uptake curve obtained at the translational energy of 2.0 eV showed a linear profile with the nitrogen dose indicating non-protective layer formation. Al-2p photoemission spectra were involved a merely-shifted shoulder structure in the higher binding energy side so that sub-nitride components were included in the AlN overlayer.
Sowa, Makoto*; Yamazaki, Daichi*; Okada, Michio*; Yoshigoe, Akitaka; Teraoka, Yuden; Kasai, Toshio*
Denki Gakkai Rombunshi, C, 129(2), p.229 - 232, 2009/02
Native oxide at CuAu(110) surface has been studied by high energy-resolution X-ray photoemission spectroscopy with synchrotron radiation. The clean surface of CuAu(110) is terminated by Au and Cu atoms with equal contents. After oxidation in the air, Cu atoms segregated on the surface and the Cu-oxide was formed. In other words, Au atoms moved into the bulk. Au atoms below the oxide prevented the O atom diffusion into the bulk. Surface index dependences of natural oxidation suggested in every cases that the diffusion of Cu atoms contributed to the oxide formation.
Iijima, Hokuto; Nagai, Ryoji; Nishimori, Nobuyuki; Hajima, Ryoichi
Denki Gakkai Rombunshi, C, 129(2), p.253 - 258, 2009/02
A high-brightness electron source of ultra-small emittance and high-average current is one of the most important components for next-generation light sources based on an energy-recovery linac (ERL). Such a high-brightness electron source can be realized by a DC photo-cathode gun driven by laser pulses tailored in temporal and spatial dimensions. We propose a novel photocathode based on a quantum cascade laser (QCL). Since ultrafast response of photo-electron emission from the QCL is compatible with tailored laser pulses, it is a candidate for the electron source for ERLs.
Murakami, Haruyuki*; Ueda, Hiroshi*; Ishiyama, Atsushi*; Koizumi, Norikiyo; Okuno, Kiyoshi
Denki Gakkai Rombunshi, B, 128(6), p.853 - 859, 2008/06
In the ITER Engineering Design Activity (EDA), it was revealed the critical current of the NbSn model coil conductor degraded by periodic strand bending caused by enormous electromagnetic force. We developed a simulation code based on the distributed circuit to investigate dependency of the critical current performance on bending strain. The results of the numerical simulations were in good agreement with the experiments. The dependence of the critical current on periodic transverse load, temperature, pitch of periodic load, thickness of Ta barrier which prevents Cu stabilizer to be contaminated by Sn, twist pitch of the strand and RRR of the bronze matrix is investigated using developed code. The results show the critical current degraded less with decreasing the pitch of the transverse load and increasing the Ta barrier thickness. It suggests that shorter twist pitch of the cable and larger bending stiffness prevent the critical current degradation.
Denki Gakkai Rombunshi, C, 127(2), p.118 - 125, 2007/02
Surface temperature and gas pressure are reaction controlling parameters of surface reactions. For instance, the following three reaction modes are selectable in the Si oxidation, "oxide film formation" in low temperature/high pressure conditions, "etching (SiO desorption)" in high temperature/low pressure conditions, and their coexistence depending on reaction conditions. Recently, it has been found that the oxidation reactions were also controllable by translational kinetic energy of O molecules. Although irradiation of high speed particles such as ion beams induces roughening of surface crystal structure and the beams reach into deep bulk, atomic and molecular beams with low incident energy restrict the reactions to be adsorption at the extreme surface. If the incident energy is larger than a potential energy barrier, a direct adsorption process may take place without trapping at physically-adsorbed states. Generally the barrier height is several eV so that surface-excited processes are available even by atomic and molecular beams with hyper-thermal incident energy. The atomic and molecular beams are very useful techniques for precise control of film formation and etching with sub-nano-meter scale. Furthermore, a research field of surface stereo-reaction dynamics may open by applying oriented-molecular-beam techniques. The molecular orientation may be effective 4th reaction controlling parameter in addition to surface temperature, gas pressure, and the 3rd parameter of incident energy. Atomic and molecular beam generation techniques, some practical applications of surface-excited reactions with low energy beams, and perspective of the surface-excited nano processes will be introduced in this review.
Teraoka, Yuden; Yoshigoe, Akitaka; Moritani, Kosuke*
Denki Gakkai Rombunshi, C, 127(2), p.133 - 139, 2007/02
Oxidation reactions at Si(001) surfaces has been studied via real-time in-situ photoemission spectroscopy for chemical bonding states of Si and O atoms, and mass spectrometry for desorbing SiO molecules with synchrotron radiation and supersonic O molecular beams in the temperature range from 900K to 1300K. With increasing an incident energy in the temperature range from 900K to 1000K, the SiO desorption yield decreased. In that case, the time evolution of an Si 2p photoemission spectrum showed that SiO structure at the surface was easily formed by the action of larger incident energy and the increased SiO coverage correlated with the decreased SiO desorption yield. Coincidence measurements of Si 2p photoemission spectra and SiO desorption yield revealed that the decrease of SiO correlated with the increase of Si component, and the SiO desorption was terminated at the oxide thickness of 0.22nm. These facts indicate that the SiO desorption take place at the topmost Si dimmers and its precursor is so called T site, in which O atoms are bonding to the dangling bonds of the dimmers. Consequently, M1 and M2 in the Dual-Oxide-Species (DOS) model were clarified to be T sites and Si states, respectively.
Ogawa, Shuichi*; Takakuwa, Yuji*; Ishizuka, Shinji*; Yoshigoe, Akitaka; Teraoka, Yuden; Moritani, Kosuke*; Mizuno, Yoshiyuki*
Denki Gakkai Rombunshi, C, 127(2), p.140 - 145, 2007/02
The initial sticking probability of O molecule on a Ti(0001)-11 surface at room temperature was measured as a function of translational kinetic energy by real-time photoelectron spectroscopy. The O 1s photoelectron spectra can be fitted well with three components A, B, and C, where the chemical shift of component B and C are +0.7 and +1.6 eV relative to the binding energy of component A (528.8 eV). Upon exposing to the O beam, component A and C appear dominantly and component B grows with an incubation time, indicating that two kinds of chemical adsorption states are concerned with dissociative adsorption of O molecule at the initial stage. The incident energy dependence of initial sticking probability shows quite different behaviours between component A and C: initial sticking probability of component C decreases monotonously with incident energy and is almost constant above 0.6 eV, while initial sticking probability of component A shows a rapid decrease followed by a gradual increase with a minimum at 0.5 eV and then decreases with two small maxima at 0.9 and 1.8 eV. The observed incident energy dependence of initial sticking probability for component A and C are discussed in terms of a trapping-mediated dissociative adsorption and a direct dissociative adsorption process.
Oda, Yasuhisa*; Komurasaki, Kimiya*; Takahashi, Koji; Kasugai, Atsushi; Imai, Tsuyoshi*; Sakamoto, Keishi
Denki Gakkai Rombunshi, A, 126(8), p.807 - 812, 2006/08
Experiments on microwave plasma generation and its application to microwave beamed energy propulsion were conducted using a 1MW-class, 170GHz gyrotron. The microwave beam was focused using a parabola reflector and plasma was initiated near the focal point in the ambient air. Plasma propagated upstream in the microwave beam channel while absorbing microwave. Its propagation velocity was supersonic when the microwave power density was larger than 75kW/cm. The propulsive impulse was measured using a cone-cylinder shaped thruster model. As a result, maximum momentum coupling coefficient was obtained at a certain plasma propagation distance. In addition, large momentum coupling coefficient was obtained when plasma was propagated at a supersonic velocity. It would be because supersonic plasma propagation forms a strong shock wave, resulting in an efficient pressure increase.