縦型ボディチャネルMOS Field-Effect Transistorを用いたマイクロプロセッサ向け高効率・高集積DC-DCコンバータとそのパワーマネジメントに関する研究

Tohoku University遠藤哲郎課

Dye-Sensitized Solar Cells Using Surface-Stabilized Nanocrystalline-TiO2 Electrodes Coated by Epoxy Polymer

In order to improve the thermal durability of dye-sensitized solar cells, epoxy polymer was coated on dyed-TiO2 electrode to prevent dye desorption under heating condition over 80 °C.  The covering effect on epoxy polymer was confirmed using impedance spectroscopy.  Using the epoxy polymer coating with Z907 Ru dye and ionic liquid electrolyte, the DSC photovoltaic durability was improved up to 90 °C, which is the highest temperature published for the DSC durability test.  Although the epoxy polymer suppressed the DSC photovoltaic effect, it enhance the thermal durability; DSC coated epoxy polymer on the dyed-TiO2 electrode was able to prolong the efficiency over 90% of the initial value at 90 °C for 550 hours.Key words: Dye-sensitized solar cells; Epoxy polymer; Ionic liquid electrolyte; Thermal durability; Heat tes

Synthesis of Formation Control Systems for Multi-Agent Systems under Control Gain Perturbations

This paper proposed a linear matrix inequality (LMI)-based design method of non-fragile guaranteed cost controllers for multi-agent systems (MASs) with leader-follower structures. In the guaranteed cost control approach, the resultant controller guarantees an upper bound on the given cost function together with asymptotical stability for the closed-loop system. The proposed non-fragile guaranteed cost control system can achieve consensus for MASs despite control gain perturbations. The goal is to develop an LMI-based sufficient condition for the existence of the proposed non-fragile guaranteed cost controller.  Moreover, a design problem of an optimal non-fragile guaranteed cost controller showe that minimizing an upper bound on the given quadratic cost function can be reduced to constrain a convex optimization problem. Finally, numerical examples were given to illustrate the effectiveness of the proposed non-fragile controller for MASs

A Method to Evaluate Accumulated Stress Using Nail Image

In this paper, we propose a method to evaluate accumulated stress by extraction the height of the lunula of the nail from a nail image. The proposed method consists of three stages: measurement, preprocessing, and stress evaluation. In the measurement, we take a nail image. In the preprocessing, we extract the height of the lunula of the nail. Then, we carry out edge detection using a hue histogram in a rectangle. In the stress evaluation, we evaluate accumulated stress at 0 to 1 using fuzzy reasoning. In order to show the effectiveness of the proposed method, we conducted experiments. These results suggested that the difference between the minimum and maximum values of the height of the lunula while the experiment might be able to determine the presence or absence of accumulated stress

A Study on growth condition analysis of rice using drones

Kazuki, M., Atsushi, I., & Hiroyuki, H. (2017). A Study on growth condition analysis of rice. In Pan African Conference on Science, Computing and Telecommunications (PACT). Nairobi: Strathmore University. Retrieved from https://su-plus.strathmore.eduSelf-sufficiency of food is one of the most important target for Japan, however, because of decreasing the population of agriculture sector due to the progress of aging, it is difficult to realize this target. One of the main reasons of decreasing the population in agriculture is hard work in the field and requirement of experience. Our study focuses on supporting aging farmers, weekend farmers and new comers in the agriculture to reduce labor and cost, and providing system to compensate experience by using ICT. For this purpose, we are developing technology to evaluate growing condition of rice and vegetables in a field by using a drone and a multi-spectrum camera. By using this technology, it might be possible to reduce the hard work under the scorching sun and to support unexperienced young farmers. In this paper, we mention the outline of the technology that we used and the result of feasibility study to analyze growth condition of rice using drone. We measured normalized difference vegetation index (NDVI) and normalized difference red edge index (NDRE) from a drone and analyzed the data to estimate growth condition of rice. We found it was possible to find the area where growth is delaying and estimate heading day.International Institute of Engineering and Technology; IEE

Cu2ZnSn(SxSe1-x)4 Thin-Film Solar Cells Utilizing Simultaneous Reaction of a Metallic Precursor with Elemental Sulfur and Selenium Vapor Sources

A Cu2ZnSn(SxSe1-x)(4) (CZTSSe) solid alloy was prepared by reacting a metallic precursor with sulfur and selenium in a closed tube simultaneously. It was confirmed that the CZTSSe alloy could be synthesized over the whole compositional range and its lattice transformation was in good agreement with Vegard's law. The crystal grain size and electrical conductivity were enhanced when the selenium content was increased. In a CdS/CZTSSe heterojunction solar cell, the photovoltaic efficiency was improved due to the enhancement of the short-circuit current in accordance with the narrowing of the optical bandgap of the CZTSSe absorber. (c) 2012 The Japan Society of Applied PhysicsArticleAPPLIED PHYSICS EXPRESS. 5(8): 81201 (2012)journal articl

Structural characterization of N-lignoceroyl (C24:0) sphingomyelin bilayer membranes : A reevaluation

Sphingomyelin (SM) is a membrane lipid and plays important roles in signaling, protein trafficking, cell growth and death. We investigated the structure of hydrated highly asymmetric SM, N-Lignoceroyl (C24:0) SM, bilayers with X-ray diffraction (XRD), simultanous small angle X-ray scattering (SAXS) and wide angle XRD, and SAXS measurements. At temperatures between two endothermic transitions of hydrated C24:0 SM bilayers, the C24:0 SM formed a ripple phase with the ripple periodicity of ~12-14 nm. About 3 month incubation at 277 K induced the formation of a stable phase with a short lamellar spacing of 5.62 nm. Based upon the structures revealed by this study and the phase behavior, we discuss the intermolecular interactions between C24:0 SM molecules in the bilayer membrane

Superior Electrochemical Performance of a Ni-P/Si Negative Electrode for Li-ion Batteries in an Ionic Liquid Electrolyte

To achieve electrode performance with both high capacity and long cycle life, we investigated the effect of the anion structure in an ionic liquid electrolyte on the electrochemical performance of an annealed Ni-P/(etched Si) negative electrode for Li-ion batteries. The electrode maintained a discharge capacity of 1890 mA h g-1 after 250 cycles in bis(fluorosulfonyl)amide-based ionic liquid electrolyte, which was approximately three times higher than that in bis(trifluoromethanesulfonyl)amide-based electrolyte