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Tokyo, Japan

Matsushita D.,Okayama University of Science | Odawara R.,Showa University | Isokawa E.,Showa University | Yamashita T.,Kougakuin University | Kumakawa T.,Japan National Institute of Public Health
AIJ Journal of Technology and Design | Year: 2013

The ultrasound positioning technology used makes it possible to collect the data of the nursing activities consecutively for one week in the respiratory disease center of the Showa University Hospital. The total of 142 person-day and 1,464 person-hour of nursing traffic line data were collected. The nursing activities were visualized in motion picture, and the room-to-room movement patterns were visualized in network models. Analysis of the data clarified the length of stay according to place, the length of traffic line of each nursing staff. According to the nurses' attributes, the resultant data showed the characteristic nursing activities. Source

Isoda H.,Kyoto University | Nakagawa M.,Shinshu University | Kawai N.,Kougakuin University | Koshihara M.,University of Tokyo | Araki Y.,Japan Building Research Institute
WCTE 2014 - World Conference on Timber Engineering, Proceedings | Year: 2014

The horizontal composite structure consisting of reinforced concrete and timber frame is tested at full scale shaking table tests in parameters of specification of the floor and number of stories. Although the eccentricity of this model is large, there was no damage against a artificial wave in return period of 495 years. Moreover, it turned out that modification of a timber frame can be reduced by raising the rigidity of horizontal diaphragm to concentrate the shearing force at the reinforced concrete wall. In a two-story specimen, the connection between a timber frame and the reinforced concrete wall was damaged. This is considered the second story is easy to be shaken because the rigidity of timber frame falls. Furthermore, the relation between a real action and the design method was considered. Source

Kim S.,University of Tokyo | Zhao P.,Zhejiang University | Aikawa S.,Kougakuin University | Einarsson E.,State University of New York at Buffalo | And 3 more authors.
ACS Applied Materials and Interfaces | Year: 2015

The intrinsic p-type behavior of graphene field-effect transistors (FETs) under ambient conditions poses a fundamental challenge for the assembly of complex electronic devices, such as integrated circuits. In this work, we present a protocol for tunable n-type doping of graphene FETs via poly(vinyl alcohol) (PVA) coating. Using graphene grown by alcohol catalytic chemical vapor deposition, functionalization of the surface by this hydroxyl anion-rich polymer results in an evolution of the FETs from p-type to ambipolar or n-type even under ambient air conditions. The doping level of graphene is strongly related to the PVA film coating parameters, such as solution concentration, hardening temperature, and hardening time. This PVA coating proves to be a simple and stable approach to tuning the Dirac point and doping level of graphene, which is highly desirable and of great significance for the future of graphene-based electronic devices. © 2015 American Chemical Society. Source

Mayama N.,Tokyo Institute of Technology | Mayama N.,Kougakuin University | Terakawa T.,University of Tokyo | Morita M.,University of Tokyo | Owari M.,University of Tokyo
e-Journal of Surface Science and Nanotechnology | Year: 2011

Recently, laser pulses on a three-dimensional atom probe have been used to trigger the field evaporation. The advantages of laser-pulse atom probes are high mass resolution and application to higher resistivity materials such as semiconductors. Most recent studies using laser pulses have indicated that the field evaporation of atoms occurred by a thermal pulsing mechanism. In this study, we analyzed the metal specimens, tungsten, nickel and aluminum, by using the hand-made 3DAP in our laboratory, and verified the mechanism of field evaporation by laser pulses. From the results, the spatial resolution might be extremely better at lower tip temperature. The difference of mass resolution between the laser-irradiated and shadow sides was observed and this might resulted from the difference of cooling duration in both sides. In the reconstruction calculation, the difference of curvature radii in the laser-irradiated and shadow sides was compensated and the spatial resolution was evaluated. © 2011 The Surface Science Society of Japan. Source

Maeda H.,Soka University | Soneda Y.,Japan National Institute of Advanced Industrial Science and Technology | Higuchi A.,Soka University | Iizuka M.,Soka University | Nagamoto H.,Kougakuin University
Bulletin of the Chemical Society of Japan | Year: 2012

Current generation from Na 2SO 3 aqueous solution was found to occur by using PAN-based carbon fibers with heat treatment at 700 °C. Sixty mL of 0.1M Na 2SO 3 and 80mL of 0.5M H 2SO 4 were added into the anode cell and cathode cell, respectively, and current generation was performed for 10 h. As a result, the current value increased from background current of 0.04 to 22.3mA after 5min. Afterward, the current was almost constant, and decreased a little in the final stage, accompanied by decrease of the amount of Na 2SO 3. The current efficiency was calculated to be 91%. The mechanism of the current generation is assumed to be described by the equation: SO 3 2- + 2OH - →SO 4 2- + H 2O + 2e -. In the current generation using a 30ω resistor, the current was 11.3 mA, so that the voltage is calculated to be 0.339V. The maximum electric power of this cell is calculated to be 3.83mW. Next, 60mL of 0.02M H 2SO 3 was added to the anode cell, and current generation was performed for 4 h as well as in the case of Na 2SO 3. As a result, the current was 8.25mA after 6min. Afterward, the value linearly decreased, and the value was 3.80mA after 3 h. The current generation almost finished after 4 h. In this case, the current efficiency was 28%. Furthermore, chemical groups on the surface of carbon fibers with heat treatment were measured by X-ray photoelectron spectroscopy. The element analysis on the surface resulted in: C, 82 atom%; N, 7.2 atom%; and O, 10.9 atom%; the existence of COO, C=O, CO, CC, C=C, CN, and C=N groups was thus suggested. © 2012 The Chemical Society of Japan. Source

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