Buildings that contain magnetic bodies (e.g., steel frameworks and reinforcing steel bars) reduce the homogeneity of the Earth's magnetic field. Such magnetic disturbance interferes with compass swinging sites and magnetic testing site. Keeping the disturbance sources away from the site enough, or using non-magnetic materials for buildings is the best solution of such a problem, however, we have to prepare a huge ground for the site, or accept very expensive construction cost of the buildings. Moreover, the magnetic shielding is useless for the disturbance of the magnetic declination. This paper proposes a method for reducing the disturbance of the magnetic declination by using ferromagnetic materials as a magnetic compensator. The procedures of the proposed method are as follows: measuring the distribution of the declination of an infected site; simulating or measuring effects of the compensators; designing a number and arrangement of the compensators by comparing the distribution of the declination on the site with that of the compensators. It is shown that the proposed method recovers the homogeneity of the site with a diameter of 30 m by about 30% by setting two compensators appropriately.

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To realize fast electromagnetic field analysis, the parallelization technique has been often introduced into the preconditioned Krylov subspace method. When the multicolor ordering is applied to parallelization of forward and backward substitution, the elapsed time of matrix calculation might increase owing to the increment of bandwidth. Therefore, the block-multicolor ordering based on the level structure arising in reverse Cuthill-McKee ordering has been developed. The validity of developed method was demonstrated on the parallelized incomplete-Cholesky-preconditioned conjugate gradient (ICCG) method. In this paper, the parallelization performance of preconditioned minimized residual method based on the three-term recurrence formula of the CG-type (MRTR) method supported by developed ordering is investigated. Furthermore, the affinity of developed ordering or cache-cache elements technique for parallelized forward and backward substitution in Eisenstat's technique is particularly examined.

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We have investigated a new dry ashing system for manufacturing of semiconductor devices. For this purpose, we have proposed a plasma system using RF transformer, which is essential to dry ashing, in order to maintain the plasma excitation. This RF transformer can achieve a balanced connection of inductive coil. This system also can improve the ashing uniformity, resulting in high capability for various plasma processing. From the measurement of antenna potential, the deviation of etching rate for balanced connection was reduced to 35%, as compared to that for the unbalanced connection, resulting in improvement of uniformity. By employing an impedance conversion method using RF transformer, the incident signal power can be supplied even though the 25 times higher load impedance than conventional plasma systems. As for the T-type impedance matching using RF transformer, the matching time was reduced to 0.2 s from 8 s for conventional L-type impedance matching system. Wide range impedance matching can be achieved by using T-type impedance matching system. It was confirmed that this system can achieve a stable plasma processing and reduction of ashing process step number, as well as reduction of power consumption and environmental load.

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Electric power equipment currently plays an important role in social infrastructures. Partial discharge (PD) may occur due to the electric field concentration in the electrical insulation parts of the electric power equipment, for example if metallic foreign matter deposited on the insulation parts. It is considered that continuous PD occurrence may lead to dielectric degradation and finally breakdown. Therefore, it is necessary to detect PD, which is precursor phenomenon of dielectric aging and breakdown. The PD detection by impedance method is often used but it is sometimes difficult to insert the detecting impedance into the actual electric circuit. In this case PD detection using an antenna method has more advantage than that using the impedance method. However, in antenna method the radiation of EM waves has been considered to be emitted directly from the PD source and the EM waves indirectly emitted from the circuit current around the PD source has been almost ignored. In this paper, it is investigated the intensities of EM waves emitted both directly from the PD source and indirectly from the circuit current around PD source.

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The plasma melting treatment of low level radioactive waste is currently in practical use. This treatment is applied to typical radioactive wastes such as carbon steel and concrete to produce a solidified product. The scaling factor method is used to evaluate the concentrations of radio-nuclides in the product. Because cobalt (Co) plays a particularly important role, it is important to clarify the behavior of Co during the treatment. In this report, we investigated the residual Co ratio in the slag produced during the plasma melting treatment of a nickel alloy. We found that a residual Co ratio of less than 10% was achieved in the slag when a Ni concentration of less than 80 wt% and a Fe concentration of more than 20 wt% was kept in the molten metal. The effect of the reduction of Co oxides by Fe on the residual Co ratio was the most dominant among the Co oxidation/reduction reactions occurring in the molten melt.

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It is well-known that concentration of generated ozone by ozone generator with dielectric barrier discharge (DBD) using high purity oxygen as a fed gas is decreased with time. The phenomenon is called “Ozone Zero Phenomenon” (OZP). As one of factors responsible for occurrence of this phenomenon is speculated to be an influence from electrode surface, we have focused our investigation on electrode surface heating generated by electrical discharge. In this paper, we studied the behavior of thermal decomposition ozone flowing ozone into the heated stainless steel pipe, and examined the temporal change of the decomposition rate of ozone. In the results, when ozone decomposition in stainless steel pipe that have not been exposed to ozone, decomposition rate of ozone has a momentarily sharp peak after that was stable. Subsequently, it was repeated thermal decomposition of ozone under the same condition we couldn't have the same results of high decomposition rate of ozone. Over 180℃ of heating temperature of stainless steel pipe, when ozone concentration flowing into the stainless steel pipe is high, decomposition rate of ozone is high. And also we found that temperature of stainless steel pipe was increasing. It was thought that cause of the temperature rise that occurs the heat generated in the ozone decomposition.

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Electrostatic precipitators are suitable for using large gas flow rate due to low pressure drop as compared with other precipitators such as fabric filter. For a cigarette smoking area, an electrostatic spray coating booth, a smoke filled room because of fire, the closed space with particulate-laden atmosphere, it is necessary for minimum volume to install air cleaner. In this work, electrostatic precipitator is tested for the influence of treated gas flow rate on suspended particle concentration decrement in a closed space. This present version electrostatic precipitator is only corona discharge unit for required simplification and smaller precipitator. An acrylic box (125 liter capacity) is used as a closed space. As results, in case of using electrostatic precipitator in a closed space with washable walls, it has been shown that particle concentration decrement rate increases with increasing gas flow rate of electrostatic precipitator.

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This paper presents an experimental study on photosensitivity of tomato seeds subjected to non-equilibrium plasma produced by polarity reversed voltage pulses in ns range. Dielectric barrier discharge repeatedly propagates along the surface of the seeds on a glass barrier between plane-plane electrodes. After the discharge treatment, the seeds are incubated on a wet filter paper at 20℃ with dark-room condition for sciophilous plants or with irradiating condition for heliophilous plants. Regardless of the discharge treatment time (0, 5, 10, 20, 30 min), most part of the seeds starts to root within 4 days and then germinate within 1 week in dark-room condition. Both the leaf size and root length after 1 week incubation are not depend on the discharge treatment in dark-room condition. On the other hand, the seeds without discharge treatment have a lower ability for germination in irradiating condition because tomato is a heliophilous plant. However, the germination ratio of the seeds in irradiating condition increases with increasing the discharge treatment time. This interesting phenomenon implies that loss of sciophilous characteristics due to molecular structure change of photoreceptor in the seed coat is caused by the repetitive barrier discharges.

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In long-distance DC submarine cables, insulating oil depletion phenomenon occurs due to limitations in pressure transmission distance. Therefore, the high viscosity insulating oil such as high viscosity oil is promising. However, if the unexpected bubbles are occurred in the high viscosity oil, partial discharge in bubbles may reduce insulation performance of the cable. In addition, the partial discharge promote the degradation of insulating oil and insulating performance may reduce. In this paper, it is investigated DC partial discharge inception voltage and repetition rate of DC partial discharge occurrence of the kraft paper impregnated with the high viscosity insulating oil. Furthermore, the charge behavior was discussed.

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CuMn-related alloys as typified by Manganin, and NiCr-related alloys such as Evanohm are widely used for the materials of standard and precision resistors. These materials have a broad resistance peak around room temperature in the resistance-temperature curve and resistance is stable and insensitive to temperature change and fluctuation around the peak. Therefore these alloys are recognized as superior materials for standard and precision resistors. The antiperovskite manganese nitride compounds, Mn₃Ag_1-xCu_xN, also show a broad resistance-temperature curve around room temperature and the temperature coefficient is comparable to those of Manganin alloys. We found out that this curvature and the peak temperature can be controlled by co-doping with Cu and In or Fe and we demonstrated that the Mn_3.03Ag_0.62Cu_0.19In_0.15N shows a low temperature second-order coefficient of resistor, 0.2 (μΩ/Ω)/K². We have also revealed that the drift rate of the resistance can be decreased by shaping a sintered sample to the 4-terminal fashion.

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In the precise phase noise measurement, we studied the influence of the relation between the frequency of the measured signal and sampling frequency on the phase noise value. It is revealed that the error of the phase noise L(f) decreases with the increasing of the offset frequency in the L(f) characteristic.

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In the reflection and transmission problem of multilayers for a plane wave incidence, electromagnetic fields are expressed using forward and backward waves from the solutions of Helmholtz equation. However, when the propagation constant becomes zero, both waves degenerate and cannot be separated. This paper clears reflection, transmission and field distributions at a propagation constant of zero in the middle regions.

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This paper presents a self-similarity-based-analysis of effects of transient electromagnetic fields on bioelectric potentials of plants. In our experiment, a single transient electromagnetic field was applied to aloe and pachira. As a result, we found that the Hurst exponent of bioelectric potential was increased by the application of a transient electromagnetic field.

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Oxygen translational energy effects on initial oxidation processes and saturation coverage of O at a Ru(0001) surface were investigated using supersonic O₂ molecular beams and synchrotron radiation photoemission spectroscopic techniques. The change of surface core level spectrum of Ru 3d_5/2 by irradiation of O₂ beams with high translational energy indicates occurrence of collision-induced oxygen migration at the oxidized Ru(0001) surface. We suggest that such collision-induced migration provides suitable sites for dissociative adsorption of O₂, resulting in higher O coverage at the Ru(0001) surface.

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Electrical treeing determines lifetime of solid insulating media in power equipment. A non-destructive observation method in non-transparent sample is needed to evaluate propagation of electrical trees. In this paper, we report observation results of electrical trees in unfilled and filled epoxy by X-ray phase contrast imaging.

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