The improved current-bridge method and its mathematical model are proposed for accurate low-impedance measurement. To realize the accurate measurements of shunt resistors smaller than 1 mΩ, the expansion of current ratio of a current transformer and a current comparator, the use of low-value resistance for reference impedance, and the development of a buffer amplifier which have flat load characteristics are required. The improved current bridge-method has the possibility for accurate measurement of shunt resistors up to 10 µΩ.

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We have carried out experimental and numerical analyses for reconstruction of permittivity distribution using a pair of long distance small size electrodes and additional arc electrodes. A reconstruction method for permittivity distribution that uses a genetic algorithm and numerical analysis (finite element method) based on measured capacitance has been proposed and investigated. However, the conventional method had a problem in accuracy. In this paper, the reconstruction method has been improved by using a Parameter-free Genetic Algorithm(PfGA) based on measured capacitance and electric potential. In addition, we have evaluated the fitness function with PfGA.

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The Spin-dependent scattering of conduction electron in metallic magnetic multilayers was investigated to reveal the optical properties which corresponded to the magnetization state. From the measurement of magnetorefractive effect in antiferro-magnetically exchange coupled Co/Ru multilayers, it was found that (1) The transmittance varied around 1% at wavelength of 1550 nm during the parallel/antiparallel spin alignment changes, (2) As a result of number of repetition and Co thickness for the multilayers, transmittance difference between the parallel and antiparallel spin alignment states had trade-off relationship with the magnitude of transmittance, (3) Asymmetric Co/Ru/Co stacking structure brought different interlayer exchange coupling field in each layer, which resulted in magnetic field sensitive transmittance.

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This paper describes the effect of ozone treatment on water dispersibility of micrometer order long multi-walled carbon nanotubes by using simple ozone generation set up. Inverter type neon transformer was used to supply required energy. The dispersed nanotubes suspension was stable for a few months after treatment. Laser Raman Spectroscopy, Fourier Transform Infrared Spectroscopy, and Transmission Electron Miscroscope were used to characterize the resulted nanotubes. Analyzed data revealed that the multi-walled carbon nanotubes were functionalized by oxygen and hydrogen containing groups.

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An electrostatic adsorption method can produce composite materials with an arbitrary structure. To develop a composite material with a higher thermal conductivity and acceptable breakdown strength, a thermal conductive Polymethylmethacrylate (PMMA) / Boron nitride (BN) composite insulating material is produced using an electrostatic adsorption method. The breakdown strength of the PMMA/BN composite as a function of the PMMA particle size showed a peak. It was recognized from the observation of SEM image that the increase of the distance between fillers which leads to increase of breakdown strength, and the increase of the orientation ratio of longer direction on the BN to electric field direction which leads to decrease of breakdown strength. These balances may determine the breakdown strength. On the other hand, the thermal conductivity exhibited the increasing trend with the increase of the PMMA particle size. The increase of the orientation ratio of longer direction on the BN to the thermal conductivity measurement direction may bring to higher thermal conductivity with the increasing PMMA particle size. It was clarified that the electrostatic adsorption method can easily produce the composite material with different properties for different purposes by changing the PMMA particle size.

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Electric breakdown form of the uniform electric field air gap is the spark discharge with a single channel. However, it was proven that pre breakdown phenomenon had been generated just before spark over discharge. In this paper, the pre- discharge of the ultraviolet radiation is defined as the following ULD By applying alternative impuls voltage to the sphere gap, this study investigated discharge form and incidence of ULD, and also effect of ULD on the spark discharge form by the combined use of standstill camera and ICCD camera with the high-speed gate. As the result, In the vertical sphere gap, it was proven that the negative half wave voltage was higher than the positive half wave voltage on the incidence of ULD in upper spherical electrode. Generally the linear spark discharge is observed in uniform electric field sphere gap at atmosphere. However, there is a case in which the bent shape of spark is sometimes observed. This discharge phenomenon was observed with a high sensitive camera. It was shown that this bent shape of spark discharge was caused by ULD.

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(Bi,Pb)₂Sr₂Ca₂Cu₃O_y ((Bi,Pb)2333) has high critical temperature (T_c) compared to REBa₂Cu₃O_y. However, (Bi,Pb)2223 tape has low critical current density (J_c) because of in-plane orientation. In addition, (Bi,Pb)2223 has a disadvantage that the J_c seriously degrades in magnetic fields. We succeeded to fabricate (Bi,Pb)2223 epitaxial thin films by pulsed laser deposition (PLD) method and post-annealing process. In addition, we tried to introduce artificial pinning center (APC) by heavy-ion irradiation to improve J_c in the magnetic field. As a result, we fabricated (Bi,Pb)2223 thin films that had high J_c in self field at 77 K of 0.4 MA/cm². The J_c in the magnetic field of (Bi,Pb)2223 thin films after heavy-ion irradiation improved. J_c in the matching magnetic field (B_ϕ) improved 20 times of (Bi,Pb)2223 before heavy-ion irradiation.

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Low density polyethylene (LDPE) and polypropylene (PP) exhibit a photoluminescence (PL) band, which emits photons with an energy of around 4.3 eV when excited by photons with energies around 6.4 eV. The origin of this PL band has been assigned to α, β-unsaturated carbonyl. In this paper, the appearance of PL was examined for four kinds of polyolefin and four kinds of biodegradable polymers. As a result, it has become clear that all the polymers show a PL band with a PL excitation spectrum and a PL spectrum similar to those of the above-mentioned PL band in LDPE and PP. The decay profiles observed for these PL bands indicate that they are fluorescence. Furthermore, the intensity of the PL becomes weak for all the four polyolefin samples and the polylatic acid sample if ultraviolet photons were irradiated to the sample. Quantum chemical calculations carried out by assuming a model of α, β-unsaturated carbonyl have revealed that the PL originates in the π^* to π transition of electrons in the carbon-carbon double bond.

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The profiles of the ion temperature and flow during magnetic reconnection in counter-helicity merging are measured in TS-4 plasma merging device. It is found the higher ion temperature and faster ion flow in the one side (out- or inboard) of the radial direction, which is attributed to the asymmetric radial profiles of the plasma potential caused by the two-fluid effect.

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