When a reduction of waste and dissolution of iron are carried out by using arc plasma, the arc radiation power should be suppressed. In those cases the radiation power from plasmas has to be precisely controlled.
Therefore, we tried to measure the radiation power from torch plasma using a power-meter. The radiation power was measured to be about 100_??_2, 000 W for an appearance plasma length of 1_??_3cm at 50_??_150A and increases in proportion to the 1.85th power of the plasma current and with increment of appearance plasma length.
The radiation efficiency for the appearance torch plasma is 8_??_27%, and also that for the wall-stabilized arc model in whole plasma length is 19-43% in the condition mentioned above in the sphere model.

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This paper describes characteristics of surface charging on a conical insulating spacer that has various contact angles with a plane cathode. The spacer is made of polymethyl methacrylate resin (PMMA) and has the contact angle between +45 and -45 degrees, where the positive sign indicates that the spacer has an obtuse angle with the cathode surface, and the negative sign an acute angle. The spacer is subjected to a ramped DC voltage, and the charging is observed by using an electrostatic probe located on the surface of the cathode close to the triple junction TJ where the insulator, cathode and vacuum meet. When the contact angle is between -25 and 0 degrees, the spacer surface acquires positive charge, which increases almost linearly with the applied voltage. The spacer with a positive contact angle acquires no charge. These results agree with the theoretical prediction which is obtained from the calculation based on the secondary emission electron avalanche (SEEA) mechanism. On the contrary, the spacer having a contact angle between -30 and -45 degrees acquires very little charge. This result differs from the theoretical prediction in which the surface acquires negative charge that increases with the applied voltage. The disagreement between the results is discussed in terms of the relaxation of electric field at TJ due to the slight negative charge accumulation.

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We have developed a measuring system which is able to detect the Maxwell displacement current (MDC) and second harmonic generation (SHG) of Langmuir films. This system enables us to study the linear and nonlinear dielectric properties of monolayers on a water surface. It was revealed that MDC and SHG signals are able to be detected at 5CB monolayers using this system.

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This paper proposes modifications to a numerical convolution algorithm, which theoretically has to be most precise amongst three convolution methods but has so far been avoided because of its poor accuracy in the numerical applications. In the paper, the three algorithms are to be examined to analyse one of the most difficult response computations for the input impulse, the ideal front-chopped impulse, and numerical results are compared with the analytically obtained values. The reason for the poor numerical performance in the method is investigated and new additional terms are to be derived so that the conventional inadequate method can yield the most precise results. Numerical analyses show that, with the proposed techniques, the accuracy of 10-5 can easily be attained in the response calculations for the input impulse. Also in the paper, it is demonstrated that the number of the multiplications involved in the convolution integral almost dominates the numerical precision for the computed response.

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A novel image processing methodology based on the field theory is proposed to visualize the electromagnetic vector fields as well as any other vector fields. The key idea of our method is that an image is regarded as a potential field. Consequently, any images can be represented by differential equations. In the static image, the images with any resolutions can be obtained by solving for the Poisson type partial differential equations. As an application, our method is applied to the practically experimented magnetic field distributing around a DC/DC converter.

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We investigated the relationship between the constituent tissue number and the localized peak SARs (specific absorption rate) inside an our newly developed MRI (Magnetic Resonance Imaging) based head model for far-field exposure with respect to all irradiating directions of the microwaves being employed for portable telephones. The FDTD (Finite-Difference Time-Domain) method was used to compute the SARs inside the MRI based head models consisting of various tissues up to fifteen kinds for 1.5 GHz microwave far-field exposure of 1 mW/cm² specified in an uncontrolled environment. As a result, we found that in the head model having less than three kinds of tissue, the localized peak SAR reaches maximum for side irradiation, decreasing with increasing the tissue kind, while in the head model with more than four kinds of tissue, the localized peak SAR reaches maximum for rear irradiation, whose value increases with the tissue kind and reaches saturation point for over five tissues including skin, fat, muscle, bone, and brain. The latter finding suggests that the head model having the above five tissues at most can be used enough for dosimetry evaluation with high accuracy.

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Pb_1-xSn_xTe solid-solutions (0_??_x_??_1) were prepared by the unidirectional solidification process with a rocking furnace. The obtained Pb_1-xSn_xTe solid-solutions, which were all p-type, were homogeneous without segregation. Pb_1-xSn_xTe solid-solutions (0_??_x_??_0.40) was characterized below 800K by its maximum figure-of-merit Z_max that shifted to high temperature with increasing x, while Pb_0.35Sn_0.65Te showed the monotonous increase of Z with increasing temperature. The high average figure-of-merit Z_av was exhibited by Pb_0.60Sn_0.40Te and Pb_0.35Sn_0.65Te at low and high temperatures, respectively. When the joined material of Pb_0.60Sn_0.40Te and Pb_0.35Sn_0.65Te, which is referred to as functionally graded material (FGM), is applied under the temperature gradient of 300-800K, the Z_av is 1.28×10^-3K^-1; this value is higher by 11 and 91% than the Z_av of the monolithic Pb_0.60Sn_0.40Te and Pb_0.35Sn_0.65Te. Thus the maximum conversion efficiency η_max of FGM reaches 11.37%, which is improved by 11 and 69% when compared with Pb_0.60Sn_0.40Te and Pb_0.35Sn_0.65Te, respectively. It is clarified that FGM can perform the high Z_av, leading to the high η_max.

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Temperature dependence of resistivity ρ of carbon black(CB)-polyethylene composites below and above percolation threshold pc is studied based on the electrical conduction mechanism. The temperature dependence of ρ of the composites below pc can be explained with a tunneling conduction model by incorporating the effect of thermal expansion of the composite into a tunneling gap. By assuming that the electrical conduction through percolating paths is a thermally activated process and incorporating the effect of thermal expansion into volume fraction p of CB, the temperature dependence of ρ above pc has been well explained without violating the universal law of conductivity and the apparent activation energy is estimated to be 0.14 eV.

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Loss current through a non-penetrated water treed polyethylene sheet has been studied by changing the applied voltagefrequency from 50 Hz to 1000 Hz of 1000 V. The change of the fundamental and 3rd harmonic components of the loss current for frequency is discussed by taking the capacitance of the water treed sheet sample to be Maxwell-Wagner two-layer capacitor: the capacitance both for the non-treed region and the closed channel region is connected in series to the parallel combination of the capacitance and the conductance for the open channel region. By assuming a non-ohmic dependence of the conductance for the open channel region, the fundamental and 3rd harmonic components of the loss current have been numerically calculatedbased on the equivalent circuit. It has been concluded that the conductance of the opened channel region in the water treedregion is directly proportional to frequency and the conductivity at 1kHz is in the order of 10^-7 S/m.

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Nitrogen implantation by plasma-based ion implantation with a negative voltage of 10 kV, a pulse width of 10 μs and a repetition rate of 100 Hz leads to formation of AIN on the surface layer of an aluminum alloy (Al-7Si) target. The AES analysis of the ion-implanted samples annealed at 400°C for 1 hour shows that there is little diffusion of oxygen at the top surface of the sample into the inside of the sample, indicating an enhancement of high-temperature oxidation resistance by AlN layer formation.

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Traffic information boards have a vital role in promoting safety and efficient road traffic, by providing the drivers with relevant traffic information on a real-time basis. To achieve good visibility and eye-catching quality, we must know the optimum number of display colors and ranges of chromaticity so that the road users can correctly recognize displayed information in a short time.
We attempted to determine the optimum number of display colors based on the categorical color (basic perceived color) technique, as well as to define the chromaticity regions for display colors so that a given color is most effectively discriminated from the others.
The results showed that the optimum number of display colors is nine, and categorization of the so-defined nine display colors on the chromaticity diagram is extremely useful in designing a traffic information board.

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In recent years, landscape lighting is more important for improvement in townscape. In this experiment, we examined how landscape lighting affect on townscape. 20 subjects evaluated impressions of dayscape and nightscape in light. It became clear that nightscape got higher estimation than dayscape, and in general, female gave higher scores than male. The results also showed that landscape lighting is effective on townscape.

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The hollow cathode discharges are characterized by a low maintaining voltage and high current density. This unique feature of the hollow cathode discharge, however, is the effect of the cathode geometry, in that electrons are trapped between the two plates due to potential distribution of the cathode fall and then can undergo a limited number of collisions with plasma particles, reverse direction and repeatedly across the cathode fall region. This possibility of making multiple passage of electrons greatly increase the ion-and photon producing effectiveness. Aims of this research are to determine the optimal shape and geometry among three typical shapes of the hollow cathode, a pair of two parallel plates, a square shaped cylinder and a circular cylinder. It is concluded that the most suitable shape of the hollow cathode is the long circular cylinder because of the lowest maintaining voltage and high current density among these three.

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