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Search Results: 1 - 10 of 1371 matches for " Toshihito Ishikawa "
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One Case of Suspected Angiostenosis Revealed by MRA Following Carotid Endarterectomy Due to a Rare Cause  [PDF]
Yuji Endo, Naoki Sato, Hidekazu Takahashi, Mamoru Ota, Toshihito Ishikawa, Katsuhiro Endo, Kenichi Ebihara
Open Journal of Modern Neurosurgery (OJMN) , 2018, DOI: 10.4236/ojmn.2018.83023
Abstract: We herein report on a case in which magnetic resonance angiography (MRA) following carotid endarterectomy revealed the appearance of angiostenosis due to an artifact of metallic powder, which was thought to have come from an old surgical instrument. The patient was a 77-year-old male. Carotid endarterectomy (CEA) was performed for stenosis in the internal carotid artery of his left neck (82%). Upon observing a decline in renal function following CEA surgery, a postoperative cervical MRA revealed the appearance of high-grade stenosis at the common carotid artery on which surgery was performed. No stenosis was revealed upon carotid ultrasonography and angiography. In the original MRA image, an orbicular low intensity area was observed in concordance with the narrow segment. 3D computed tomography (3D-CT) revealed a metallic finding, suggesting it was an artifact caused by metal powder. Close inspection of the metal surgical instruments used during surgery revealed slight damage to a suture snare which had been used for 30 years. Going forward, it is necessary to pay attention to old surgical instruments, introduce a system by which the number of years and the frequency of use of each surgical instrument can be learned, and replace them with new equipment as necessary.
Methyl Termination and ATR-FTIR Evaluation of n-Si(111) Electrode towards Photoelectrochemical Cell Fabrication  [PDF]
Toshihito Ohtake
Journal of Surface Engineered Materials and Advanced Technology (JSEMAT) , 2013, DOI: 10.4236/jsemat.2013.33022

We confirmed methyl termination on n-Si(111) surface by ATR-FTIR measurement, which was fabricated by a photo chloro-reaction and its methylation. The coverage of the methylation was about 63.7%, and the surface was not re-terminated by hydrogen. Photoelectrochemical properties of the n-Si(111) were measured as an electrode for a photoelectrochemical cell, and an onset potential obtaining photocurrent for the methyl terminated n-Si(111) electrode was observed as negative shift at 70 mV comparing with that of the hydrogen terminated n-Si(111) electrode. Therefore, the negative shift would be expected for improving open circuit voltage towards solar cell.

ATR-FTIR and XPS Evaluation of Alkyl Immobilization by Hydrosilylation on n-Si(111) for Photoelectrochemical Cell Electrode  [PDF]
Toshihito Ohtake
Journal of Surface Engineered Materials and Advanced Technology (JSEMAT) , 2013, DOI: 10.4236/jsemat.2013.33A002

An electrode development was needed with high efficiency and low costs as next generation solar cells. We attempted the electrode fabrication for a photoelectrochemical cell by immobilizing functional groups on a n-Si(111) surface. The immobilization was applied by hydrosilylation terminated with ester (hydrophobic) or carbonyl (hydrophilic) group. Results confirmed the immobilization on the Si surface by measuring ATR-FTIR and XPS.

Fabrication by Fine Particles and Evaluation of WO3 Photo Semiconductor Electrode  [PDF]
Toshihito Ohtake
Journal of Materials Science and Chemical Engineering (MSCE) , 2013, DOI: 10.4236/msce.2013.16007
Abstract: Application of semiconductor particles has been noticed to solve energy problems as photocatalysis for O2 evolution in water splitting etc. We are trying fabrication of semiconductor electrode by n-WO3 particle toward O2 evolution in water splitting. The electrode obtained high photooxidation properties of water as preventing effective recombination between electrons and holes by utilizing fine semiconductor particles. Particularly, application of suspension prepared by ball milling was able to obtain fine n-WO3 thin film and the remarked semiconductor properties.
In Situ ATR-FTIR Observation about Surfactant/Hydrogen-TerminatedSi(111) Interface in Solution  [PDF]
Toshihito Ohtake
Journal of Surface Engineered Materials and Advanced Technology (JSEMAT) , 2014, DOI: 10.4236/jsemat.2014.42008

Development of novel functional devices has been expected by modification for Si surface. This study investigated immobilization and roles of the Si surface with flowing surfactant by in situ ATR-FTIR method. This result suggested that the surfactant prevented oxidation of the hydrogen-terminated Si surface from the higher concentration in aqueous solution. These would guard the Si surface against H2O molecules.

Single Phase Li4Ti5O12 Synthesis for Nanoparticles by Two Steps Sintering  [PDF]
Toshihito Ohtake
Journal of Materials Science and Chemical Engineering (MSCE) , 2015, DOI: 10.4236/msce.2015.32002
Abstract: Li4Ti5O12 has been noticed about a negative electrode of a high powered and safe lithium ion secondary battery. These properties require single phase, high crystallization, larger specific surface area and fine nanoparticles. This study carried out the noble synthesis of Li4Ti5O12 using a solid phase synthesis by two steps sintering. These results showed Li4Ti5O12 of 6.1 m2·g-1?and diameter of 110 nm with the single phase and high crystallization. Li2TiO3 will play an important role in this reaction, obtained by pre-sintering as a precursor.
Edge State and Intrinsic Hole Doping in Bilayer Phosphorene
Toshihito Osada
Physics , 2014, DOI: 10.7566/JPSJ.84.013703
Abstract: Using a simple LCAO model by Harrison, we have qualitatively studied the edge state of bilayer phosphorene, which is a unit structure of the layered crystal of black phosphorus. This model successfully reproduces the isolated edge state in the bulk gap in monolayer phosphorene. In bilayer phosphorene, however, it shows that edge states are almost buried in the valence band and there is no isolated midgap edge state at the zigzag edge. Since the buried edge state works as acceptor, holes are doped from the edge state into the bulk. This gives a possible explanation for p-type conduction in undoped black phosphorus. Under the vertical electric field, the intrinsic hole doping is reduced because a part of edge states move into the gap. These features of bilayer phosphorene might be better suited for device application.
Surface Transport in the ν=0 Quantum Hall Ferromagnetic State in the Organic Dirac Fermion System
Toshihito Osada
Physics , 2015, DOI: 10.7566/JPSJ.84.053704
Abstract: We discuss the surface magnetotransport in the quantum Hall (QH) ferromagnetic state expected in the organic Dirac fermion system \alpha-(BEDT-TTF)_2I_3. The QH ferromagnetic state is one of the possible \nu=0 QH states in the two-dimensional Dirac fermion system resulting from the degeneracy breaking of the n=0 Landau level. It is characterized by the helical edge state. We have studied the interlayer surface transport via helical edge state in the multilayer QH ferromagnet, in which the bulk region is insulating. We have clarified that the surface conductivity is much less than e^2/h and decreases as the magnetic field is tilted to the normal direction of the side surface. These features explain the observed interlayer magnetoresistance in \alpha-(BEDT-TTF)_2I_3.
Li4Ti5O12 Synthesis with High Specific Surface Area and Single Phase  [PDF]
Toshihito Ohtake, Ken-ichiro Iijima
Journal of Materials Science and Chemical Engineering (MSCE) , 2015, DOI: 10.4236/msce.2015.39009
Abstract: We have investigated a novel Li4Ti5O12 synthesis with high specific surface area, high crystallization and single phase and its mechanism. The method was performed with a solid phase synthesis by using CH3COOLi·2H2O and anatase TiO2 via Li2TiO3 as an intermediate in pre-sintering at 500°C and sintering at 750°C. This result showed specific surface area of 12 m2/g and single phase- Li4Ti5O12 by applying the high specific surface anatase TiO2 as a precursor.
Cell range expansion using distributed Q-learning in heterogeneous networks
Toshihito Kudo and Tomoaki Ohtsuki
EURASIP Journal on Wireless Communications and Networking , 2013, DOI: 10.1186/1687-1499-2013-61
Abstract: In this article, we propose a scheme to determine the bias value of each UE by using Q-learning algorithm where each UE learns its bias value that minimizes the number of outage UEs from its past experience independently. Simulation results show that, compared to the scheme using optimal common bias value, the proposed scheme reduces the number of outage UEs and improves network throughput.
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