Kogakuin University is a private university in Shinjuku, Tokyo, Japan. The predecessor of the school initially named "Koshu Gakko" which is one of the oldest private engineering schools in Japan, was founded in 1887 by educator and politician, The President of Tokyo Imperial University's President Koki Watanabe and other professors of Tokyo Imperial University.The Koshu Gakko was an evening school and it had civil, mechanical, electric, architecture, ship building, mining, metallurgical, and chemical engineering courses since it established. In 1928. the school was renamed "Kogakuin" which means "Institute of Engineering" or "Institute of Technology" in Japanese.In 1949, the school was chartered as a 4-year university. In 1964, the school had master's course and in 1966 it had doctorate course in the graduate school. Wikipedia.
Takagi R.,Kogakuin University
IET Electrical Systems in Transportation | Year: 2012
Thanks to the recent developments, the superconducting cables using high-temperature superconducting (HTS) materials are now expected to reduce feeding losses in the power supply network for DC electric railways. However, by connecting the HTS cables with the normal conducting wires electrically, heat intrusion is inevitable; to suppress heat intrusion to an acceptable level, interconnection becomes a large and costly installation. This means that the use of HTS cables as the replacement for normal conducting feeder wires in the DC railway feeding network is unrealistic because of the need for frequent interconnections between the feeder and contact wires. By combining the results obtained by a number of cases of multi-train simulation and a preliminary estimate of the refrigeration losses, the author shows that, by using HTS cables to replace some of the feeding substations, rather than the feeder wires, the introduction of HTS cables in the feeding network of DC electric railways may have positive effects of saving energy. © 2012 The Institution of Engineering and Technology.
Okuzumi S.,Tokyo Institute of Technology |
Takeuchi T.,Tokyo Institute of Technology |
Muto T.,Kogakuin University
Astrophysical Journal | Year: 2014
Large-scale magnetic fields are key ingredients of magnetically driven disk accretion. We study how large-scale poloidal fields evolve in accretion disks, with the primary aim of quantifying the viability of magnetic accretion mechanisms in protoplanetary disks. We employ a kinematic mean-field model for poloidal field transport and focus on steady states where inward advection of a field balances with outward diffusion due to effective resistivities. We analytically derive the steady-state radial distribution of poloidal fields in highly conducting accretion disks. The analytic solution reveals an upper limit on the strength of large-scale vertical fields attainable in steady states. Any excess poloidal field will diffuse away within a finite time, and we demonstrate this with time-dependent numerical calculations of the mean-field equations. We apply this upper limit to large-scale vertical fields threading protoplanetary disks. We find that the maximum attainable strength is about 0.1 G at 1 AU, and about 1 mG at 10 AU from the central star. When combined with recent magnetic accretion models, the maximum field strength translates into the maximum steady-state accretion rate of 10-7 M yr-1, in agreement with observations. We also find that the maximum field strength is 1 kG at the surface of the central star provided that the disk extends down to the stellar surface. This implies that any excess stellar poloidal field of strength ≳ kG can be transported to the surrounding disk. This might in part resolve the magnetic flux problem in star formation. © 2014. The American Astronomical Society. All rights reserved.
Kanemura S.,University of Toyama |
Machida N.,University of Toyama |
Shindou T.,Kogakuin University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2014
We propose a simple model to explain neutrino mass, dark matter and baryogenesis based on the extended Higgs sector which appears in the low-energy effective theory of a supersymmetric gauge theory with confinement. We here consider the SU(2)H gauge symmetry with three flavours of fundamental representations which are charged under the standard SU(3)C×SU(2)L×U(1)Y symmetry and a new discrete Z2 symmetry. We also introduce a Z2-odd right-handed neutrino superfield in addition to the standard model matter superfields. The low-energy effective theory below the confinement scale contains the Higgs sector with fifteen composite superfields, some of which are Z2-odd. When the confinement scale is of the order of ten TeV, electroweak phase transition can be sufficiently of first order, which is required for successful electroweak baryogenesis. The lightest Z2-odd particle can be a new candidate for dark matter, in addition to the lightest R-parity odd particle. Neutrino masses and mixings can be explained by the quantum effects of Z2-odd fields via the one-loop and three-loop diagrams. We find a benchmark scenario of the model, where all the constraints from the current neutrino, dark matter, lepton flavour violation and LHC data are satisfied. Predictions of the model are shortly discussed. © 2014 The Authors.
Yoshimura F.,Hokkaido University |
Tanino K.,Hokkaido University |
Miyashita M.,Hokkaido University |
Miyashita M.,Kogakuin University
Accounts of Chemical Research | Year: 2012
Zoanthamine alkaloids, isolated from organisms in the Zoanthus genus, constitute a distinctive family of marine metabolites. These molecules exhibit a broad spectrum of unique biological properties. For example, norzoanthamine inhibits interleukin-6, the key mediator of bone resorption in osteoporosis, providing a promising drug candidate for a disease that affects more than 10 million people over age 50 in the United States. In addition, these natural products are characterized by a densely functionalized heptacyclic framework, as exemplified by the structures of zoanthamine, norzoanthamine, and zoanthenol, which makes them extremely attractive targets for chemical synthesis. Prior to our first total synthesis of norzoanthamine in 2004, the densely functionalized and complex stereostructures of the zoanthamine alkaloids had impeded synthetic studies of these molecules. In this Account, we describe our synthetic approach toward the total synthesis of zoanthamine alkaloids, focusing on how we overcame various synthetic challenges.At the beginning of our synthetic studies, we aimed to develop an efficient route that was flexible enough to provide access to several members of the family while allowing the synthesis of various analogues for biological testing. Our first project was the total synthesis of norzoanthamine, and we established an efficient synthetic route based on a novel strategy involving the following key features. First, we used a sequential three-component coupling reactions and subsequent photosensitized oxidation of a furan moiety to synthesize the precursor for the key intramolecular Diels-Alder reaction. Second, the key intramolecular Diels-Alder reaction constructed the ABC-ring carbon framework bearing two adjacent quaternary asymmetric carbon atoms at the C12 and C22 positions in a single stereoselective step. Third, we installed the third quaternary asymmetric carbon center at the C9 position by an intramolecular acylation of a keto alcohol followed by successive O-methylation and C-methylation reactions with complete stereoselectivity. Through the exploitation of a deuterium kinetic isoptope effect, we then efficiently synthesized the alkyne segment. Next, a coupling reaction between the alkyne segment and the amino alcohol segment and several subsequent synthetic transformations afforded the bis-aminoacetalization precursor. Finally, bis-aminoacetalization reactions carried out in one-pot constructed the DEFG-ring system and culminated in the total synthesis of norzoanthamine. Our synthetic route to norzoanthamine also allowed access to other zoanthamine alkaloids from a common synthetic intermediate, by way of stereoselective introduction of the C19 methyl group for zoanthamine, and isoaromatization for construction of the aromatic A-ring in zoanthenol. The chemistry described here not only allowed us to overcome formidable synthetic challenges but also opened a completely chemical avenue to naturally occurring zoanthamine alkaloids and their synthetic derivatives. © 2012 American Chemical Society.
Ichikawa N.,Kogakuin University
Journal of Electrostatics | Year: 2010
Electronic apparatus in partially opened metal boxes often malfunctions due to electrostatically induced voltage. The induced voltage (induced potential difference, IPD) produces when charged bodies exist and move close. Objectives of this study are (1) to improve the voltage level capable of measuring an induced voltage, (2) to discriminate its polarity. In this study, the IPD and its polarity are demonstrated by means of a neon lamp and a photomultiplier tube. The results will be useful to estimate the value and polarity of the IPD as well as to help with the basic design of printed circuit boards. © 2010 Elsevier B.V.