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Nakajima, Takahiro; Kumazawa, Mineo; Shigeta, Naotaka; Kunitomo, Takahiro; Nagao, Hiromichi; Matsumoto, Hiroshi*
Gekkan Chikyu Gogai, (47), 174 Pages, 2004/00
We introduce a new electromagnetic sounding method called EM-ACROSS (ElectroMagnetic - Accurately Controlled Routinely Operated Signal System). The feature of the propagation of the elecromagnetic waves is defferent from that of elastic waves. We introduce the present state of the development of a system at Tono Geoscience Center. We estimate the posivility of the exploration of deep Earth's crust.
Nakajima, Takahiro; Kunitomo, Takahiro; Nagao, Hiromichi; Kumazawa, Mineo; Shigeta, Naotaka
Gekkan Chikyu Gogai, (47), p.179 - 184, 2004/00
We have developed an electromagnetic sounding method, called EM-ACROSS (ElectroMagnetic - Accurately Controlled Routinely Operated Signal System), which can be used for the exploration of the frequency range below hundreds hertz. A trial observation has been done at Tono area for more than one year. We have obtained the accurate averaged transfer function, and also observed its temporal variation.
Hasada, Yoko; Kumazawa, Mineo; Kayoko, Tsuruga,; Kunitomo, Takahiro
Gekkan Chikyu Gogai, (47), p.61 - 68, 2004/00
A data set acquired by ACROSS is the transfer functions between transmitted signal and received one sampled within limited bandwidth. We have developed a method to extract event localized in time domain from frequency-domain transfer function and estimate the traveltimes, which is called the Sompi event analysis.
Kayoko, Tsuruga; Kumazawa, Mineo; Kunitomo, Takahiro; Shigeta, Naotaka
Gekkan Chikyu Gogai, (47), 34 Pages, 2004/00
Focusing on the cover layer materials (as the Radon Barrier Materials), which could have the effect to restrain the radon from scattering into the air and the effect of the radiation shielding, we produced the radon barrier materials with crude bentonite on an experimental basis, using the rotary type comprehensive unit for grinding and mixing, through which we carried out the evaluation of the characteristics thereof.
Tsuruga, Kayoko; Kunitomo, Takahiro; Hasada, Yoko; Kumazawa, Mineo; Shigeta, Naotaka;
Gekkan Chikyu Gogai, (47), 95 Pages, 2004/00
There is a problem of vibration in a diagnosis system of helical evaporator tubes installed in a nuclear power station. Numerical simulations are implemented on the assumption that the vibration is caused by the Coulomb's friction. An analytical model is derived as a large scale nonlinear vibration system and a lot of computational cost would be required to carry out the simulations. The Transfer Influence Coefficient Method, which has high accuracy and efficiency in numerical computations, is applied and efficiently implements the simulations. The vibrations are qualitatively reproduced by the simulations. It enables us to make a pre-evaluation of several means to suppress the vibrations are qualitatively reproduced by the simulations. It enables us to make a pre-evaluation of several means to suppreess the vibration and the most effective devise is expected through the simulation.
Junzo, Kasahara; Kayoko, Tsuruga; Hasada, Yoko; *; Kumazawa, Mineo; Kunitomo, Takahiro
Gekkan Chikyu Gogai, (47), 141 Pages, 2004/00
Focusing on the cover layer materials (as the Radon Barrier Materials), which could have the effect to restrain the radon from scattering into the air and the effect of the radiation shielding, we produced the radon barrier materials with crude bentonite on an experimental basis, using the rotary type comprehensive unit for grinding and mixing, through which we carried out the evaluation of the characteristics thereof.