The accuracy of numerical results obtained by computers is hard to know mathematically. At present it is only natural to gain confidence in the results by computer runs. As a way to achieve reliability an interval method has been proposed for the eigenvalue problem. In the interval method eigenvalues are computed by solving the characteristic equation of a matrix. There are severe ristrictions on the starting intervals allowed for the method.
This paper describes an alternative way for finding the eigenvalues and eigenvectors of a given matrix with real elements. It employs Householder's transformation, the method of bisection and the QR algorithm, based on triplex arithmetic operations. The only limitation to matrices is that all the eigenvalues are to be simple. The matrices may be symmetric or nonsymmetric.
In triplex arithmetic the number is represented by describing simultaneously the approximate value and the error. In parallel to the result of operation, the rounding error produced in that operation is determined, which is summed up for each operation. When a series of operations is completed, the range of existence for the result can be determined automatically from the result of computation and the sum of errors.
Some numerical examples are given, 3×3 to 6×6 Lotkin matrices included.

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This paper describes the mapping theory which is useful for the analysis of the electric field in three-dimensional anisotropic media. The mapping relations of various electric quantities between two anisotropic media with charge distribution are presented. In this mapping, an anisotropic medium can be transformed to an equivalent isotropic one. The simple isotropic mapping function is presented, and it is made clear that the isotropic permittivity can be determined arbitrarily and the convenience is caused by a similarity transformation. Furthermore, it is shown that the mapping conserves the field continuity on the boundary when one mapping function is applied to the compound regions consisting two or more different anisotropic media. In addition, the isotropic mapping for the compound region is discussed and the mapping function in some limitations is presented.

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There have been some interests recently in studying the propagation of an ion acoustic soliton in a plasma consisting of two components in electron temperature, each with its unique electron temperature T_h and T_c and density N_eh and N_ec. The addition of the second component opens the possibility of excitation and propagation of both a compressive and rarefactive soliton. The ion acoustic soliton propagation can be described in terms of a Sagdeev potential U(Φ) with hot and cold electrons. The most striking features are that 1) in the compressive soliton, the characteristics between the Mach number μ and the normalized alnplitude eΦ/(kT_h) are reversed when T=T_h/T_c varies, and 2) in the rarefactive soliton, they are reversed when N=N_eh/N_ec varies.
In this paper Sagdeev potential is analyzed to clarify the property of above-mentioned compressive and rarefactive solitons.

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A lightning impulse voltage is applied repeatedly 10, 000 times to an electrode system of positive point to plane and two electrode systems of positive point to plane which has installed a protrusion in low pressure air of 8Torr. The flashaver voltages where the rate of arc occurrence times to discharge times is 50% (henceforth, call 50% flashover voltage, V_A50) are examined. Moreover, effects of the increase of the discharge times on changes of the V_A50 in the range of 0.1-30Torr and the protrusion surface forming a part of the cathode surface are examined, and the change of the protrusion surface is observed and analyzed by an electron probe micro-analyzer and a x-ray photoelectron spectroscope.
The main results are as follows.
(1) Even in the case that the 50% flashover voltage of the electrode system rised and saturated in the relatively little discharge times, when the discharge times were increased further, the 50% flashover voltage became higher and again saturated, depending on the electrode system geometry and the oxidation of the cathode surface.
(2) The 50% flashover voltages became higher in the vicinity of 8Torr in which the voltage was applied so many times, and the curves of the V_A50 to the air pressures of 0.1-30Torr before and after the many discharges differed.
(3) After a number of discharges, CuO and Cu₂O were formed and the adsorptive oxygen molecule or moisture appeared on the copper cathode surface, and as a result the 50% flashover voltage became higher.

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Organic silicate materials such as TEOS are attracting attention as new silicon sources because of better film quality, excellent step coverage in particular, in atmospheric pressure CVD as well as low pressure (high temperature) CVD and plasma CVD. In AP CVD, addition of ozone (O₃) lowers deposition temperatures to around 400°C, and the CVD reaction is thermal (chemical). TEOS/O₃ AP-CVD is now well known for very good conformality. Deposition rate of the CVD depends on base materials to be deposited on. On thermal oxide deposition rate is lower and film quality is poorer than on silicon. These facts can be attributed to that the CVD reaction is rate-limited by a surface reaction. Characteristics of TEOS, OMCTS and HMDS/O₃ CVD are discussed centering on the base material dependence, which is related to hydrophile of base materials and structure of the organic silicon materials. Two step deposition method is proposed to improve quality of the film deposited on thermal oxide.

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This paper describes the change of AC breakdown voltages of 6.6kV dry-cured XLPE cables during the immersed accelerated test. The cause of the reduction of the breakdown voltages was investigated. The accelerated test was carried out by applying 6.9kV of 1kHz at room temperature with the conductor strands and insulation shields kept constantly moist. It was found that the breakdown voltage decreased to about half of the initial breakdown voltage until 3 months aging. This decrease was found to be mainly caused by the moisture permeating the cables during the accelerated test. After 3 months, the breakdown voltage decreased due to bow-tie trees which touched inner or outer semi-conductive shields.

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This paper proposes an image processing system as detectors of tracking deterioration on the surface of organic insulating materials. The binary images for the image processing system were able to detect the trace of the deposited carbon path. It was also observed that the area of the carbon path increases as the carbon path length increases under all test voltages. In addition, the time dependence of the area for Bisphenolic based epoxy resin (EX) differs from that of Polycarbonate (PC). The EX shows a negative voltage dependence. On the other hand, the PC shows the positive one.
In order to investigate the different voltage dependences between two samples, the light pulses for the scintillation discharge were measured by the light pulse count method. It was clarified that the voltage dependence of the carbon area for each sample corresponds with the accumulated numbers of light pulse. Therefore, it is indicated that the visual image provides quatitative and real time information regarding the propagation process of the carbon path.

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An experiment was carried out to investigate the effect of addition of composite rare-earth oxide (55La₂O₃-34Nd₂O₃-10Pr₆O₁₁) on magnetic properties of anisotropic BaO•6Fe₂O₃ magnets. It was found that the magnetoplumbite structure was stabilized by addition of composite rare-earth oxide to BaO•6Fe₂O₃ compound, and these Ba-La-Nd-Pr system ferrite had excellent properties as a parmanent magnet. The optimum conditions of making an anisotropic magnet and some properties of typical sample are as follows; composition: BaO•6Fe₂O₃ added with 5wt% composite rare-earth oxide, semisintering condition 1, 225°C×1.0h in O₂ gas, sintering condition 1, 325°C×0.5h in O₂ gas. Magnetic properties; J_m=0.425T, J_r=0.461T, H_cJ=178kA/m H_cB=176kA/m, (BH)_max=33.6kJ/m³, K_A=3.25×10⁵J/m³, H_A=1, 536kA/m, T_c=449.3°C. And then, the magnetic properties of BaO•6Fe₂O₃ magnet added with 2wt% composite rare-earth oxide, 0.5wt% SiO₂ and 0.5wt% CaO was equivalent to that of BaO•6Fe₂O₃ magnet added with 5wt% compiosite rare-earth oxide.

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