Proceedings of the Japan Academy, Series B
Online ISSN : 1349-2896
Print ISSN : 0386-2208
ISSN-L : 0386-2208
Volume 77 , Issue 6
Showing 1-7 articles out of 7 articles from the selected issue
  • Panayiotis VAROTSOS, Nikos SARLIS, Efthimios SKORDAS
    2001 Volume 77 Issue 6 Pages 87-92
    Published: 2001
    Released: October 17, 2006
    JOURNALS FREE ACCESS
    Small amplitude Seismic Electric Signals (SES), are not accompanied by readily detectable variations of the horizontal components of the magnetic field. This does not hold for strong SES activities, i.e., before earthquakes with M-6.5 at epicentral distances of -100 [km]. The instrumentation used to obtain such conclusions is described. Attention is focused on a careful calibration of the coil magnetometers that were in operation at loannina station when the strong SES activities associated with the 6.6 earthquake at Grevena-Kozani were recorded. These magnetometers act as dB/dt detectors for periods longer than around half a second; furthermore their output is“neutralized”after 200 [ms] from the“arrival”of a fast step magnetic variation. In other words, a signal recorded by these magnetometers should correspond to a magnetic variation that has“arrived”at the sensor less than 200 [ms] before the recording. This property is critical for the study of the time difference between the variations in the electric and the magnetic fields. The variations in these fields“arrive”simultaneously (within experimental accuracy) from the usual nearby artificial sources, while for magnetotellurics the magnetic recordings“precede”those of the electric field. Both behaviors differ from that observed in the case of strong SES activities, a matter described in the accompanying paper.
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  • Panayiotis VAROTSOS, Nikos SARLIS, Efthimios SKORDAS
    2001 Volume 77 Issue 6 Pages 93-97
    Published: 2001
    Released: October 17, 2006
    JOURNALS FREE ACCESS
    The 6.6 Grevena-Kozani EQ that occurred on May 13, 1995 was preceded by two strong SES activities recorded (with a sampling rate 1 sample/sec) at Ioannina station on April 18 and April 19, 1995. These activities were accompanied by observable variations of the horizontal magnetic field (unfortunately, the vertical magnetometer was out of order). The magnetic recordings were found to“arrive”1-2 [s] after the electric field variations. The same value of the time-lag is found for both the whole SES activities and portions of them. A careful inspection shows that this time-lag cannot be attributed to the instrumentation; for example, MT disturbances recorded just before (or after) the SES activities exhibit an opposite behavior, i.e., the magnetic recordings“precede”the electric ones as naturally expected.1) The fact that SES electric field variations“precede”the accompanied magnetic ones by a time-lag of the order of one second excludes any possibility of attributing them to a nearby artificial source. This time-lag can be understood only if we consider that the trasmission of the fields obey diffusion type equations and the epicentral distance was about 80 [km]. The measurable time-lag between these variations may provide a tool for (1) improving the prediction of the epicenter and (2) distinguishing true SES from artificial noise (the latter distinction becoming possible if the epicentral distance is significant, e.g., several tens of km).
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  • Junzo KASAHARA, Shigeru NAKAO, Kazuki KOKETSU
    2001 Volume 77 Issue 6 Pages 98-103
    Published: 2001
    Released: October 17, 2006
    JOURNALS FREE ACCESS
    During the 2000 Miyake jima volcanic activities, forty-six steps on tilt meters and earthquake bursts in Miyake-jima were observed over a 40-day period. These tilt steps and earthquake bursts seem to have a diurnal or semi-diurnal periodicity. Earthquake bursts were high around tilt steps. The correlation of tilt steps and calculated shear strain components of tidal force was examined. If we consider some scatter of direction, shear strain components of tidal deformation show good coincidence with tilt steps. The coincidence is best in the N45°E-N70°E directions. A model to explain tilt steps by tidal triggering is proposed. According to this model, the tidal force triggered or accelerated the opening of gaps between volcanic conduit and capped-rock near the summit. The shear movements in the N45°E-N70°E directions might effectively act to open gaps between conduit and capped-rock and/or existing cracks. Vapor, sulfur dioxide, and/or carbon dioxide are candidates for the pressure source in the volcano conduit. If the tidal effect on volcanism in Miyake-jima can be applied to other cases, many similar observations can be explained.
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  • Yukio ISOZAKI, Ayano OTA
    2001 Volume 77 Issue 6 Pages 104-109
    Published: 2001
    Released: October 17, 2006
    JOURNALS FREE ACCESS
    Nearly 10 million years before the Permo-Triassic boundary (PTB; ca. 251 Ma) characterized by the greatest mass extinction in the Phanerozoic, the Middle-Upper Permian boundary marked another big biotic decline almost comparable in magnitude to the PTB event. Two stratigraphic sections spanning across the Maokouan (Middle Permian)-Wuchiapingian (Upper Permian) boundary (MWB) were newly found in paleo-atoll limestone within the Jurassic accretionary complex in Kamura and Akasaka, Japan. These two sections share almost identical litho- and biostratigraphy that records a remarkable biotic extinction of large-shelled fusultnids and a sharp lithologic change exactly across the MWB. These new data, as the first evidence from the shallow-water mid-oceanic realm, suggest that a quick environmental change occurred in a global scale across the MWB. A thin, acidic tuff recognized at the MWB horizon in the paleoatoll limestone has a potential utility as a key bed for global correlation and suggests a possible link between the end-Permian biosphere crisis and the explosive acidic volcanism.
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  • Akikazu MATUSMOTO, Sadamu NAGAHAMA
    2001 Volume 77 Issue 6 Pages 110-114
    Published: 2001
    Released: October 17, 2006
    JOURNALS FREE ACCESS
    The photopolymerization reactivity and the polymer structure control of several benzylammonium sorbates as the 1, 3-diene monomers in the crystalline state are described. The polymerization of the 4-methyl-substituted benzylammonium derivative proceeds to give a stereoregular polymer in the crystalline state under UV irradiation, similar to naphthylmethylammonium sorbate. We have also succeeded in the synthesis of a ladder polymer by topochemical polymerization of p-xylylenediammonium disorbate as the bifunctional monomer under similar conditions. The polymerization mechanism and the stereochemical structure of the resulting polymers are discussed based on the results of the X-ray single crystal structure analysis as well as IR, NMR, and ESR spectroscopic studies. We have demonstrated a unique two-dimensional polymer synthesis by topochemical polymerization via a radical chain mechanism based on polymer crystal engineering, which is useful for the control and design of the polymerization reactivity and the polymer chain and crystal structures.
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  • Kazue KURIHARA, Masashi MIZUKAMI
    2001 Volume 77 Issue 6 Pages 115-120
    Published: 2001
    Released: October 17, 2006
    JOURNALS FREE ACCESS
    The macrocluster formation of propionic acid adsorbed onto silica (glass and silicon oxide) surfaces from propionic acid-cyclohexane mixtures has been studied using surface forces measurement, adsorption excess isotherm measurement and Fourier transform infrared spectroscopy (FTIR) in the attenuated total reflection (ATR) and the transmission (TS) mode. In pure cyclohexane, the interaction extended to only 2-3nm and described as the van der Waals force. On the other hand, unusually long-range attraction was observed in the presence of propionic acid in the concentration range of 0.1-20mol%. At 0.5mol% propionic acid, the attraction appeared at 67±8nm and turned into repulsion below 2nm upon compression. This attraction was accounted for in terms of the bridging of opposed adsorption layers of propionic acid on the surfaces. The thickness of the adsorption layer was estimated as half of the attraction range to be 34±4nm for 0.2-1.0mol% propionic acid, which agreed well with the thickness calculated from the adsorption excess amount of propionic acid, 38±9nm, assuming that the adsorption layer consisted of pure propionic acid. Chemical interactions involved in the formation of the adsorption layers of propionic acid were investigated by FTIR-ATR spectroscopy using silicon oxide as a substrate. The hydrogen-bonded OH absorption of propionic acid around 3120cm-1 was observed at 0.1mol% propionic acid where the contribution from the bulk solution was small. The linear structure of the surface cluster initiated from the surface silanol groups was demonstrated from the peak position and the dichroic analysis of the hydrogen-bonded OH absorption. An application of this phenomenon with respect to the nano-scale coating technique was demonstrated by the photo-polymerization of the acrylic acid monomer adsorbed on the silica surfaces. Photo-irradiation of the silica substrates for 20min in 0.1mol% acrylic acid produced extremely uniform and flat polymer films with a thickness of≈25nm, which exhibited an average difference in the height of less than 0.2 nm for a 3μm×3μm area on the surface.
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  • Tadashige NOZAKI, Hisako FUJIHARA, Nobuo KAMADA, Otoya UEDA, Tsuyoshi ...
    2001 Volume 77 Issue 6 Pages 121-124
    Published: 2001
    Released: October 17, 2006
    JOURNALS FREE ACCESS
    Various studies show that poly(ADP-ribose) polymerase-1 (Parp-1) is involved in genomic stability. We previously established Parp-1 knockout (Parp-1-1-) mice by disrupting Parp-1 exon 1. Parp-1-1- and Parp-1+/+ embryonic fibroblasts were isolated and they became immortalized spontaneously after two months of culture. Parp-1-1- embryonic fibroblasts showed extensive hyperploidy compared to Parp-1+1+ counterparts, and most of the cells contained a single nucleus. These results suggest that disruption of Parp-1 could result in the perturbation of chromosomal ploidy control through endoreduplication.
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