After numerous simulations, authors could unsuccessfully design an impulse current calibrator, whose output's time parameters (front time, T₁ and time to half the peak, T₂ ) are quite close to ideals defined in IEC 60060-1. The investigation for the failed trial was commenced. Using normalized damped oscillating waveform e^-tsin(ωt), a relationship of the ratio T₂/T₁ and undershoot value are studied for all possible value for . With this relationship, it is derived that 1) one cannot generate an ideal wave form unless one has to accept a certain margin for the two parameters, 2) even with the allowable margin, one can generate a wave form only in a case a value for T₁ is smaller and T₂ is larger than standard values. In the paper, possible time parameter combination, which fulfils IEC 60060-1 requirements, is illustrated for a calibrator design.

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We have observed the co-seismic electromagnetic phenomena such as earth potential difference (EPD) variation in many observation sites of both Miyagi and Akita Prefectures. So far, in any earthquakes we observed clear signals of the EPD variation. However, the amplitude of observed EPD signals are very different at each site. To explain this difference, firstly we assumed the EPD generation mechanism to be the streaming potential. Secondarily, the underground circumstance is modeled as the composer of groundwater table, capillary tubes and fine tubes. The model how EPD variation signals appear is postulated to explain the observed data. The relative position of the ground water table against the buried electrodes is examined to explain the observed data. The groundwater table may be very sensitive to the appearance of the EPD variation. If electrodes were buried a few meters below the ground surface, we could observe the EPD signals in the case of shallow groundwater table.

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Among several numerical methods, a Finite Element Method (FEM) has been adopted in various engineering problems. In such a background, it is necessary to instruct university students in the numerical analysis. The authors have designed and implemented the numerical analysis education support system for learning electromagnetic fields with Graphical User Interface (GUI) based on the server-client model using Java. In the paper, a feasibility study on the student laboratory class in the third year is described.

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Both an experimental observation and a numerical modeling of streamer development in SF₆-N₂ gas mixtures are performed and the results are compared with each other. By using a steep-front square high voltage in the measurements, it is possible to keep the constant condition of the electric field during the streamer development. Minimum sparkover voltage and streamer velocities obtained from the numerical modeling show good agreement with those from the experimental observation, and the change in the streamer velocity against the gas mixture ratio shows a similar tendency.

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The emission radiated from electric and electronic equipments is evaluated through OATS. Recently, it is not fully prepared the environment for OATS because of a variety of communication radiation sources (e.g., digital television broadcast and cellular phone station). Therefore, the EM anechoic chambers are becoming more and more important as EMI test site. On the other hand, the EM anechoic chambers are needed high performance in order to cut down EMI countermeasure cost and calculate the antenna factor. The objective of this paper is mainly to present the EM wave absorber design in order to obtain within ±2dB against the theoretical site attenuation values in the 10m semi anechoic chamber at 30MHz to 300MHz. We get the necessary reflectivity of EM wave absorber by the basic site attenuation equation. We design the open-top hollow pyramidal new hybrid EM wave absorber consisted of 180cm long dielectric loss foam and ferrite tiles. Then, we design the 10m semi anechoic chamber by using the ray-tracing simulation and construct it in the size of L24m×W15.2m×H11.2m. More over, we measure the site attenuation of the constructed 10m semi anechoic chamber by using the broadband calculable dipole antennas. As the result, we confirm the validity of the designed open-top hollow pyramidal new hybrid EM wave absorber.

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The electronic toll collection (ETC) system is now beginning to widely use as part of the ITS which aims for the new environment in Japan road traffic. However, it is not fully prepared the environment for ETC system because of the communication interference caused by the multiple reflections from the constructions, such as the tollgate canopy and the elevated highway. In this paper, we propose a new improvement method to suppress the multiple reflections from the constructions by using EM wave absorber. We present the necessary absorption of EM wave absorber in the oblique incidence at 5.8GHz circular-polarized wave, abbreviated as CP wave, by using a basic radio propagation principle. Then, we develop the CP' EM wave absorber. Moreover, we experiment at the ETC system under the elevated highway in order to demonstrate the effectiveness of the CP' EM wave absorber. As a result, we were able to confirm effectiveness of the proposed new method.

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The apple snail, Pomacea canaliculata, brought to Japan from Taiwan for human consumption in the 1980s, has come to be considered as deleterious for rice cultivation. The snail is unable to injure young rice plants while receiving electric shock because the snail retracts its entire body into its shell and shuts its aperture with its operculum. Electric shock should be applied intermittently to reduce the amount of energy that is wasted when the snail is in its shell made of one of the insulator. The minimum electric shock required for controlling snails and the time required for movement after application of electric shock to determine the frequency of each electric shock were investigated using two methods; vertical and horizontal application of the electrical stimulation. The results showed that there is a strong correlation between the strength of electric shock and the reaction of the snails, and electric shock made snails inactive when it was applied 0.35 A/m² in the horizontal direction and 0.45 A/m² in the vertical direction with water of 11 mS/m. A positive correlation was also found between electric shock and the reaction of the snails and shell height. In comparison with larger snails, the smaller snails had higher threshold levels against electric current density because their shorter feet tended to have lower voltage dorp. Moreover, the frequency of electric shock should be chosen the minimum duration for the inactive condition, and it was approximately 10 seconds. Consequently the direction of electric current should be in the horizontal direction above 0.35 A/m² and the frequency of electric shock should be less than 10 seconds for practical use. However, electric shock would have to be maintained at greater than 0.35 A/m² because snails might become habituated to electric shock and water in paddy field would have high electric conductivity.

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This paper proposes an automatic classification system for impulsive electromagnetic (EM) noises. The classification is based on the frequency spectrum of EM waves emitted from partial discharges in power apparatus. This concept is validated by confirming the reproducibility of waveforms of EM waves. In order to clarify the effectiveness of our proposal, six defects are considered: a needle-plane electrode, a strain insulator, a pin-type insulator, FDF (Forced Draft Fun), CBP (Condensate Booster Pump), and COOL-P (Cooling Water Pump). Neural networks are used to classify the frequency spectrum of EM waves. As a main result, these sources are well classified with the recognition rate of 80% or better. This is supported by treating a thousand of EM pulses.

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As a first step to understand the processes taking place in a pulsed xenon discharge, the temporal behavior of the radial metastable atom distribution in a xenon lamp was measured by IR laser absorption spectroscopy. During the first 10μs after starting the discharge, high electron density and the depletion of the ground state atoms at the center of the discharge brought about an almost flat distribution of the metastable atoms within the half-radius area. Following that, the metastable atom density became higher at the center than outside because of recombination between electrons and ions. After the metastable density increase and following voltage cut off, the metastable density decreases again. Considering the diffusion equation alongside these results, it becomes clear that the decrease of the metastable density is caused by quenching to the resonace level from the metastable level or three-body collisions forming excimers.

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An authoring software for online lecture contents has been developed. Various multimedia such as HTML, SMIL and Real System are integrated in this software, which is named EzClassMaker. Professors who are not familiar to the information technology can make the online lecture content including the sound and movies, and place the content on Leaning Management System by using this software. Only the microcomputer with this software and a microphone (or a movie camera) is requested to make the content.

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For the care of people in bed, the assistance or support for their body motion is an essential task. In the absence of helpers or at night, however, preventive measures are being required to avoid sudden accidents such as a fracture of bone due to a fall from a bed or suffocation due to turning in bed. In this paper, a new method was proposed for monitoring their body motion, which is able to supply a 24-hour monitoring with a low cost and high accuracy. Being different from commonly used methods in which three-dimensional coordinates for the markers attached to the body are obtained from sequential image processing, this proposed method employs two-dimensional positioning detectors to determine the three-dimensional coordinates of the markers via a perspective view transformation. A prototype system was developed based on our ideas, and its measurement evaluation was conducted for a fixed marker and a repetitive circular motion marker. The results showed that positions obtained 1% for the fixed marker vary within and reproduce with an error of ±3.6 mm for the repetitive circular motion marker with a swing of ±100 mm. An application of the system to a subject turning in bed demonstrated the system's feasibility for body motion monitoring from the motion tracks together with rolling angles and the breathing of a subject.

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Lanthanum chromite (LaCrO₃) has excellent chemical stability at high temperature. LaCrO₃ doped with alkaline earth metals has high electric conductivity as a heater material having operating temperatures starting from room temperature. The purpose of this study is to fabricate heaters using thin films of LaCrO₃ doped with dopant Ca which is deposited on alumina substrates with different purities by RF magnetron sputtering and evaluate their characteristics under any conditions. Thin films of Ca doped LaCrO₃ shows different heating characteristics with dc current drive for the different purity of alumina substrate. In case of lower purity (95.3%), long term stabilities of LaCrO₃ thin film heaters showed the increase of the residence with increasing time. On the other hands, in case of high purity (approximately 99.5%), the resistance was almost constant. It is speculated that impurities, such as SiO₂, contained in a alumina substrate enhance the migration of La, Cr, or Ca atoms through the Pt electrode and increase the resistance of a heater. It is considered the increase of resistance is caused by such reaction.

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ITO(Indium-Tin-Oxide) has been now widely used as the transparent anode for organic light-emitting devices(OLEDs). We used various methods of ITO surface treatment and examined the effects of them by measuring contact angle and calculating surface energy. We also prepared OLEDs with ITO treated by each method, and estimated their characteristics. The surface of ITO treated by UV-O₃ or O₂-plasma was more hydrophilic than that treated by only organic rinse or no treatment, and consequently the characteristic of the OLED was improved. We suppose these treatments affect the hole injection from ITO into organic layer, due to ionization potential or surface cleanness. We also investigated time degradation of NPD films on the ITO substrates. The films deposited with high deposition rate porycrystallized faster.

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The polycyclic aromatic compounds were added to low density polyethylene (LDPE) with the concentration of 0.1-1.6wt% to restrict the generation of electrical tree in LDPE. The compounds used were naphthalene(Nf), anthracene(An), tetracene (Te), pentacene(Pn) and 9,10 bromo-anthracene(Br-An). AC(50Hz) high voltage was applied to a needle electrode inserted to a block of PE with the additive. The experimental results show that when the concentrations of additive are in the range from 0.5wt% to 0.75wt%, the tree inception voltage for LDPE/An is 3.5-4 times higher than that for LDPE without additive. However, the addition of An is not able to restrict the propagation of tree generated in the specimen. The addition of the other additives except for Nf has much less effect for the increase in the inception voltage than that of An, and the inception voltage for LDPE/Nf is almost the same as that for LDPE without additive. The mechanisms for increasing the tree inception voltage by An were discussed refereeing to our experimental results with UV absorption spectrum, DSC and SPM. SPM observation revealed that high density fibrous construction is formed only on the surface of LDPE/An and surface roughness on LDPE/An is almost 0.17times smaller than that on the other materials. The roughness of the other samples is not small as that of LDPE/An. It is estimated that free volume at an interface between electrode and polymer for LDPE/An is smaller than that for LDPE without additive. It is considered that the increase in the inception voltage for LDPE/An results mainly from the small size of free volume at the interface.

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Monte Carlo simulations of electron swarms in oxygen have been performed to study effect of a magnetic field on ozone generation. The result shows that superimposition of the magnetic field perpendicular to an electric field reduces dissociation rate of oxygen molecules. Reduction of the dissociation rate is due to depression of electron energy in the swarm and backscattering of electrons to the cathode. It is also confirmed that a radial expansion of the swarm is constrained in the case of the magnetic field parallel to the electric field.

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