Our visual characteristics are affected by various visual environments. In this experiment, we examine how object colors look in dense fog. Namely, 7 male subjects evaluated their color perception of object color in the presence of fog and in the absence of fog. Subject's task is to match the apparent color of 10 test-color-cards in dense fog with the Munsell color. In the presence of fog, apparent color showed a drastically decrease both in the chroma and in the value. We are confident that in the visual environment involving fog, these results are extremely helpful both in basic study and in practical use.

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A new estimation method for the radiated far-field emission from PCBs (Printed Circuit Boards) with parallel traces was proposed. An equation for calculating the electric far-field due to common-mode currents on the traces being not always electrically short, was theoretically derived. The FDTD (Finite-Difference Time-Domain) method was used to compute the common-mode currents for the electric far-field prediction. A comparison of the predicted far-field strength with the results acyually measured for two types of prefabricated sample PCBs having parallel traces was carried out in order to validate the above prediction approach. As a result, good agreement was obtained between the estimation and the measurement in the broad frequency range from 30 MHz to 1 GHz.

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A weakly ionized plasma channel produced by an ultra-violet laser was adopted for laser triggered lightning method. It is excellent for guiding ability because of expecting a long plasma channel. Triggering ability, however, is not expected so much because of being low plasma density. So, it is studied to improve the triggering ability using a kHz high repetition rate of KrF excimer laser. Using this type of laser it is so expected of the accumulation effect caused by charged particles that the plasma density can be enhanced and it connects to improve triggering ability. Moreover, up to the present, the studies of laser-triggered lightning with kHz high repetition rate have not been reported. The density of charged particles produced by this type of laser was measured. From this experiment, the accumulation effect of charged particles and enhanced triggered discharge were confirmed in the case of laser repetition rate of 1 kHz.

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Non-thermal plasma has been used to remove nitric monoxide (NO) in a mixture of nitrogen, oxygen, and wa-ter vapor simulating the flue gases from a power station stack. Ammonia has been known to be useful for high efficiency removal of NO_x. The effects of the ammonia and ammonium nitrate were studied. The addition of NH₃ to the exhaust gas was effective. The ammonium nitrate has an effect to decrease NO₂ in gas mixture.

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We have been studying the charging phenomena on an insulating spacer in vacuum. According to our previous studies, a probe technique for the real-time observation of charging as well as a numerical simulation technique based on Secondary Electron Emission Avalanche (SEEA) mechanism are very useful for understanding the charging phenomena. However, details of the charging process have not been fully understood until now. In the present study, we have conducted current and luminescence measurements in combination with the probe measurement in order to clarify the charging process. A cylindrical insulator made of PMMA (poly-methyl-methacrylate), A_l2O₃ or Teflon was examined under a ramped voltage excitation. As a result, it has been shown that pulsive currents (mA order in each peak), accompanied by luminescence, flow during the charging. The probe signal (electric field strength at cathode) is an almost linear function of the charge amount obtained by integrating the current pulse. These results show that the current composed of short pulses is responsible for the surface charging in vacuum.

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The paper describes the calculation results of induced current in human models due to a 50-Hz uniform magnetic field. The human models with five internal organs were constructed from the second order curved elements. The calculation method is the boundary element method (BEM). In the homogeneous model, the maximum current density appears near the body surface at the front and back for a vertical magnetic field and appears at the left and right side of the body for a horizontal one. Little effect was found on the induced current of each internal organ for two different postures. In the human model with internal organs, conductivity of the organs exhibits a considerable effect on the distribution of the induced current and electric field. The important result is that the induced current density in an organ varies proportionally to its conductivity in many cases.

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We investigated the factors that influence the dielectric properties such as breakdown strength and conduction current of linear low-density polyethylene. The film with a lower melt-flow-rate shows a higher dielectric strength. Furthermore, the catalyst to polymerize the film affects the dielectric strength, although additives in the film scarcely affect its electrical properties. The effect of crosslinking on the dielectric breakdown in linear low-density polyethylene was found to be similar to the one in low-density polyethylene.

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This paper deals with recovery behavior of hydrophobicity of silicone rubber for polymer insulator housing after depositing artificial contaminant on its surface. Artificial contaminant was prepared based on TONOKO and sodium chloride. Recovery behavior of hydrophobicity of a specimen deposited with artificial contaminant was evaluated by receding contact angle and diameter of water droplets dropped on its surface. The specimen kept under high temperature and dry conditions recovered hydrophobicity faster than the specimen kept under low temperature and high humidity conditions. Also the specimen which contains much more amount of LMW (Low Molecular Weight) component recovered hydrophobicity faster than the specimen which contains less amount of LMW component. But adding low viscosity silicone oil to the silicone rubber lowered rubber properties, such as hardness, elongation, and tensile strength, and it was also clarified that an excess amount of low viscosity silicone oil made lowered tracking resistance performance of the specimen.

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We have measured photoluminescence (PL) spectra induced in polypropylene (PP) by irradiation of photons from an ArF excimer laser under different irradiation atmospheres (air, O₂, and vacuum) and thoseinduced by synchrotron radiation in order to examine the photo-induced chemical reaction. The PL due tothe oxidation that relates essentially to the degradation of PP is examined in this research by comparingPL spectrum induced by the irradiation in vacuum and the one induced in oxygen. The important resultobtained is that the PL component around 4 eV decreases with an increase in irradiation time irrespectiveof the irradiation atmosphere. On the other hand, a new PL component around 3 eV appears and increaseswith an increase in irradiation time only in the case that the laser irradiation was done in vacuum. Bycomparing the PL properties observed in low-density polyethylene used for reference, the decrease of the4-eV PL is considered to be due to the decomposition of unsaturated ketone or benzene ring present in PPas an impurity or antioxidant, while the appearance and increase of the 3-eV PL is probably caused by the double bonds induced by the irradiation. These results suggest that different chemical groups are induced depending on the irradiation atmosphere.

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The transient capacitance and transient charging current simultaneous measuring system of liquid crystal (LC) cell is presented. The waveform of the current-voltage dependence of the LC cells is measured by applying a triangle wave of voltage with a step bias. We discuss transient characteristics of orientation of liquid crystal molecules and impurity ions in liquid crystal cell from the transient capacitance, transient resistance and the transient charging current. This transient simultaneous measuring system is useful for investigating the relationship between the polarizations due to impurity ions and the orientation of liquid crystal molecules.

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Providing the drivers with relevant traffic information on a real-time basis, LED (light emitting diode) traffic information boards have a vital role. On the other hand, we must know the optimum range of chromaticity for display colors so that the drivers can correctly recognize the displayed information in a short time. In this experiment, we tried to define the optimum chromaticity regions for display colors so that a given color is most effectively discriminated from the others. Categorization of the display colors on the chromaticity diagram is extremely useful in designing a LED traffic information board.

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Approximation functions, which determine the switching impulse voltage parameters using the definition for the lightning impulse, are proposed. The paper demonstrates any waveform defined as a switching impulse voltage by the IEC can precisely be processed with negligibly small error. The details of the approximation technique are also discussed in the paper.

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