Kirino M.,Hazama |
Tomita I.,Tokyo Institute of Technology
Macromolecules | Year: 2010
As a novel thermal latent anionic initiator for lower temperature applications, a new class of aminimide, 1,1-dimethyl-1-(2-hydroxypropyl)amine benzoylformimide (BFI), was synthesized from benzoylformic acid methyl ester in 95% yield, and its thermal rearrangement behavior was studied in detail. Thermal rearrangement of BFI proved to take place on heating above 80 °C via the Curtius rearrangement mechanism, generating the corresponding isocyanate, hydroxyamine, and their further reaction products. BFI proved to catalyze the polymerization of epoxides and epoxide/thiol system on heating above 80 °C. They exhibit both the long pot life and the low-temperature rapid polymerization in the presence of BFI which supported the promising applications of BFI as an efficient thermal latent base catalyst for anionically polymerizable/curable systems. © 2010 American Chemical Society.
Nakano K.,Hazama |
Matsushima S.,Kyoto University |
Kawase H.,Kyoto University
Bulletin of the Seismological Society of America | Year: 2015
The objective of this study is to investigate in detail the characteristics of strong ground motions separated from acceleration Fourier spectra of ground motions observed by K-NET, KiK-net, and the Japan Meteorological Agency (JMA) Shindokei network in Japan using the generalized spectral inversion method. The separation method used here is the same as that proposed by Kawase and Matsuo (2004), with the same reference bedrock site at YMGH01. We include events with magnitude equal to or larger than 4.5 observed from 1996 to 2011. Our results are in good agreement with previous results regarding source, path, and site characteristics, but with higher stability thanks to the increased amount of data. We obtain site amplification factors common to all source types but with different Q-values for three source categories: crustal earthquakes (type C), subducting plate-boundary earthquakes (type B), and intraplate earthquakes (type I). We find that our frequency-dependent Q-values are comparable to those of previous studies, and that the obtained Q-values depend on the traveling regions. As for the geometric spreading factor n, we find that for type B and type I earthquakes, the value is close to 1.0 as expected, but type C earthquakes show apparent frequency dependence. From the corner frequencies of source spectra, we calculate Brune’s stress parameters and find a clear magnitude dependence, in which smaller events tend to spread over a wider range while maintaining the same maximum value. This means that stress drops for larger events would be maximal.We confirm that this is exactly the case for several mainshock–aftershock sequences. The average stress parameters are 5.1 and 6.0 MPa for types B and I, and 0.8 MPa for type C. This large difference between types B and I and type C can be explained primarily by the depth dependence of stress parameters. © 2015, Seismological Society of America. All rights reserved.
Shimizu H.,Kyoto University |
Koyama T.,Kyoto University |
Ishida T.,Kyoto University |
Chijimatsu M.,Hazama |
And 2 more authors.
International Journal of Rock Mechanics and Mining Sciences | Year: 2010
In this study, the radial strain control method for uniaxial compression tests was introduced in the distinct element method (DEM) codes and the Class II behavior of rocks was simulated. The microscopic parameters used in the DEM models were determined based on laboratory uniaxial compression tests and Brazilian tests carried at Äspö Hard Rock Laboratory, Sweden. The numerical simulation results show good agreement with the complete stress-strain curves for Class II obtained from the laboratory experiments. These results suggest that the DEM can reproduce the Class II behavior of the rock successfully. The mechanism of the Class II behavior was also discussed in detail from the microscopic point of view. The loading condition and microscopic structure of rocks will play an important role for the Class II behavior. © 2009 Elsevier Ltd. All rights reserved.
Eto K.,Kyoto University |
Matsui M.,Kyoto University |
Sugahara T.,Hazama |
Tanaka-Ueno T.,University of Arts
Zoological Science | Year: 2012
The endemic Japanese frog Rana tagoi is unique among Holarctic brown frogs in that it breeds in small subterranean streams. Using mitochondrial 16S ribosomal RNA and NADH dehydrogenase subunit 1 genes, we investigated genealogical relationships among geographic samples of this species together with its relative P. sakuraii, which is also a unique stream breeder. These two species together form a monophyletic group, within which both are reciprocally paraphyletic. Rana tagoi is divided into two major clades (Clade A and B) that are composed of 14 genetic groups. Rana sakuraii is included in Clade A and split into two genetic groups, one of which forms a clade (Subclade A-2) with sympatric R. tagoi. This species-level paraphyly appears to be caused by incomplete taxonomy, in addition to introgressive hybridization and/or incomplete lineage sorting. Rana tagoi strongly differs from other Japanese anurans in its geographic pattern of genetic differentiation, most probably in relation to its unique reproductive habits. Taxonomically, R. tagoi surely includes many cryptic species. © 2012 Zoological Society of Japan.
Sukegawa A.M.,Japan Atomic Energy Agency |
Anayama Y.,NEO Tech |
Okuno K.,Hazama |
Sakurai S.,Japan Atomic Energy Agency |
Kaminaga A.,Japan Atomic Energy Agency
Journal of Nuclear Materials | Year: 2011
A flexible heat resistant neutron shielding material has been developed, which consists of polymer resin with 1 wt% boron. The neutron shielding performance of the developed resin, examined by the 252Cf neutron source, is almost the same as that of the polyethylene. The outgas of H 2, H 2O, CO and CO 2 from the resin have been measured at ∼250 °C environment. The resin will be applied around the port of the vacuum vessel as an additional shielding material and reduce the neutron streaming from a superconducting tokamak device such as JT-60SA. © 2011 Elsevier B.V. All rights reserved.