The generation mechanism of the jumping and dropping phenomena, which appears when the ceramic resonator with high-Q is driven by the resonance frequency, has not been revealed.
This papaer proposes the model of the jumping and dropping phenomena and its hysteresis which occurs on the ceramic resonator. The generation mechanism of these phenomena is cleared comparing the analysis of the model and the mechanical resonance curve. The generation mechanism of these phenomena is described using the proposed model which is formed by the two types of resonance curves existing in each territory of the linear and the non-linear.
The results of the examination of this model are in good agreement with the experimental value. It shows that the propsed model is correct.

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Electrostatic precipitator (ESP) has been used to improve the visibility index and clean the air in highway tunnels. Most of particles in the highway tunnels are composed of carbon. Decrease of the collection efficiency due to particle re-entrainment is important problem when ESP collects carbon particles that have low electric resistance. In this work, we discuss the exhausting process of re-entrained particles from ESP. The process was discussed by particle deposit condition on collecting electrodes. The results show that the collected particles on collecting electrodes migrate to downstream with jumping between grounded and positive collecting electrodes. The particle shapes change into sphere from pearl chain when particles have been jumped between collecting electrodes. Therefore, re-entrained particles deposit on middle of electrodes.

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In this study, a doubled Q-switched Nd: YAG Laser (λ=532nm, FWHM=6nsec., repetition rate=10Hz) which has high peak power and lower thermal effect than that of continuous wave laser, was employed to investigate the production of active oxygen from photosensitzer. As the photosensitizer, Zinc coproporphyrin III (Zn CP-III) was prepared. The production of active oxygen from the photosensitizer was measured by method of luminol chemiluminescence. As the result, the waveform of luminol chemiluminescence was acquired. The peak wavelength of luminol chemiluminescence was approximately 430nm, The chemiluminescence intensity of luminol increased with increase in the Zn CP-III concentration and the pulse energy.

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The collection efficiency for the particle larger than 1μm decreases due to the re-entrainment on an electrostatic precipitator (ESP) for carbon particles. The re-entrainment means that particles on collecting electrodes refly to gas flow, The re-entrainment may be prevented by increasing the adhesive force between particles and collecting electrodes.
In this work, we have investigated the prevention of re-entrainment by spraying water with surfactant into the gas flow. Diesel exhaust particles were used as particulate matter for the experiments. The particle concentration was measured using a scanning electron microscope which is able to count the particle lager than 0.01μm. As a result, collection efficiency was improved by spraying water with surfactant into ESP. The results indicate that re-entrainment and particle agglomeration on collecting electrode are prevented.

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This paper describes improvement on heating efficiency in microwave oven. An asymmetrical rotary stub is proposed as an adjustable matching element, and the characteristics of the efficiency is investigated by the combination of the adjustable stub with the high power sensor in the past developed. As a result of automatic adjustment of matching, it is found that the VSWR is improved to be in the region of 1.5_??_4.0 and the heating efficiency is increased by 3_??_21(%) for water of 100_??_300(cc) used as a practical load.

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In a balanced three-phase system, three-phase current distortion factor of three-phase AC power sources has been expressed by applying conventional single-phase current distortion factor which is defined for a single phase system. However, in an unbalanced three-phase system, it is difficult to express the three-phase current distortion factor for distorted three-phase AC currents by means of the conventional single-phase current distortion factor. For instance, the conventional current distortion factors for the three-phase AC currents are usually different from each other in the unbalanced three-phase system. To solve above problem, this paper proposes a novel definition of the three-phase current distortion factor. The proposed three-phase current distortion factor is quite effective for the unbalanced threephase system as well as the balanced three-phase system.

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Electron transport coefficients, including ionization coefficients and excitation coefficients in a dc-type PDP (Plasma Display Panel) Cell are obtained by a MCS (Monte Carlo Simulation) method under the electric field distributions that are calculated by a FMS (Fluid Model Simulation) method under the LFA (Local Field Approximation). These results are compared with the results which calculated by the MCS assuming the LFA. Discrepancies are recognized in the results between them. In particular, as the gradients of electric field against the position become larger, the differences of ionization coefficients and excitation coefficients become more evident. This suggests that the LFA is not sufficient to describe the behaviors of electron swarm in the PDP Cell where the strong nonequilibrium regions are included.

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The breakdown voltages of a longer gap configration in gaseous nitrogen and air which are necessary for designing the superconducting electrical power apparatuses are measured at the temperatures of 293K and 93K. The quasi-uniform electric field made by a sphere-to-sphere electrode whose diameter is 150mm and whose gap length is about 10mm-100mm is used in the measurement of the breakdown voltages. When 50Hz ac and dc voltages are applied to the sphere-to-sphere gap, the breakdown voltage in nitrogen and air obeys the Paschen's law at both room temperature and cryogenic one(93K). When 1.4/50μs lightning impulse voltage is applyed to the gap, the 50% breakdown voltage of nitrogen also obeys the Paschen's law under the condition of UV irradiation to the cathode electrode. However, the breakdown voltage in air at the temperature of 93K increases in the case of lightning impulse voltage applications, and the delay time from the impulse voltege application to breakdown occurrence is apparently longer at 93K than that at 293K.

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Composite insulation system of liquid nitrogen and solid insulator, which are widely employed in high Tc superconducting equipments, can be deteriorated by partial discharge (PD) generated in highly stressed region such as a triple junction. In this study, effect of thermal bubbles, which can be generated by AC loss of the superconductor, on PD characteristics were investigated using composite insulation system. Thermal bubbles had little effects on PD characteristics because they were rejected from the high field region by gradient force. Under atmospheric pressure condition, small bubbles were generated as a result of local vaporization by PD energy injection. However, those bubbles disappeared in sub-cooled liquid nitrogen and the number of PD pulses drastically decreased. A theoretical model was proposed to estimate temperature rise due to the PD energy injection into liquid nitrogen.

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This paper proposes a new method of scanning beams from several radio-frequency quadrupole (RFQ) accelerators on a target, and gathering them into a bundle of ion beams on the target which is prepared for a neutron source of boron neutron capture therapy(BNCT). The scanning apparatus is composed of a solenoid coil and wobbling magnets. The method will be found to produce various forms of ion intensity distributions on the target, and as a result, to provide the neutron source with favorite neutron flux distributions for BNCT.

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Non-flammable large-capacity and liquid-cooled transformers have been developed. The transformers are used perfluorocarbon (PFC) liquid and SF6 gas for the cooling and insulating systems.
This paper describes the uniform breakdown characteristics in PFC liquid with the solubility of SF6 under AC and lightning impulse voltages. The breakdown strengths of the PFC liquid with dissolved SF6 have been effected the PFC vapor and SF6 gas pressure above the liquid. Further, the breakdown voltage decreases extremely in existence of gas bubbles in the liquid under AC.

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In recent years the oil filled(OF) cables have been confined to the extra high voltage of 275_??_500kV. In these circumstances, much longer drying time due to thicker insulation is required in order to remove moisture from insulating paper during OF cable manufacturing. Therefore it is important to decide the appropriate drying time to avoid the thermal degradation caused by excessive thermal drying. Additionally, in the cable insulation of semi-synthetic paper such as polypropylene laminated paper, the prolonged drying time because of gas barrier of plastic layer is inevitable in the same manner. By the basic and applicable investigation for the drying judgment of OF cable insulation, the following conclusions have been proved.
(1) Dielectric loss in very low frequency region (approx. 10^-2Hz) can be gotten in the insulating paper during vacuum thermal drying by the measurement of absorption current. This dielectric loss, which is considered to be attributable to the ionic conduction(proton migration), become lower with the decrease of water content and higher due to thermal degradation during thermal drying.
(2)In order to clarify drying limitation of insulating paper, tan δ of oil impregnated paper was precisely examined in low water content range(less than 0.1wt.%). Consequently, unlike the most results in past reports, the influence of water content on tan δ appeared more dominantly in low temperature (room temperature), rather than in high temperature (100°C).
(3) Using the absorption current value, which corresponds to the dielectric dispersion in approx. 10-2Hz, as an indicator during OF cable drying process, it has been proved that required drying time can be decided appropriately according to the difference depending on each cable structure.

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A comparison of the observed relative magnitude of the 3rd harmonic wave to the fundamental one of ac loss current I₃/I₁ and phase of the 3rd harmonic wave θ₃ with the calculated ones has been done for water tree cross-linked polyethylene. The model used for this calculation takes account of non-linear electrical conduction mechanism in the water tree region and contains two parameters; one of them is a parameter characterizing the effect of electric field on the non-linear electrical conduction and the other is a conductivity at low electric fields depending on frequency of applied voltage. It has been found that this model can explain qualitatively the changes in I₃/I₁ and θ₃ for applied voltage and its frequency.

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Magnetic thin films for magnetic drive type micro-actuators must possess high magnetostriction and soft magnetism simultaneously to ensure large magneto-mechanical coupling. In order to realize such films, binary TbFe amorphous alloy films and ternary TbHoFe amorphous alloy films were prepared by rf-sputtering on glass substrates, where the latter films were aimed to prompt soft magnetism without loosing large magnetostriction by eliminating large local magnetic anisotropy of the former alloy films. The effect of thermal annealing for the internal stress relief on magnetic properties was also examined. By combining suitable choice of composition and heat treatment, films with magnetostriction λ=300×10^-6 at H=1kOe and magnetostrictive sensitivity at zero field (dλ/dH)H=0=450×10^-9Oe^-1 were obtained for a film with Tb₃₂Ho₈Fe₆₀ after being annealed at Ta=325°C for 1h in a vacuum, the magnitudes of which are larger than those of TbFe amorphous alloy films. In addition, to check the performance characteristic of micro-actuators, cantilever-type actuators were constructed by depositing films on polyimide foils and the deflection of the free end of the cantilever by applied field was measured, from which these films were proved to be available for micro-actuator.

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In this paper, we studied the ac partial discharge (PD) characteristics and their luminescence patterns in air gap in series with fissure-like interface. The interface was formed by attaching two solid insulating blocks of epoxy resin and it was put between needle-plate electrodes and a small air gap. The PD characteristics were measured with a pulse method using a computer aided PD analyzing system and their luminescence was recorded to the photographs simultaneously.
PD and its luminescence were observed to occur from the tip of the needle electrode and its magnitude showed a good relation to the luminescence. In case of the nominal interfacial gap of 0μm (without spacer) the luminescence patterns of the specimen with a smooth interface show that the extension of PD streamers into the interface is restricted even at higher voltage and the roughened interface allowed especially for the positive PD streamers to crawl along the interface with increase of the applied voltage. When the interfacial gap became large, however, the growth of PD streamers crawling along the smooth interface became conspicuous than that along a roughened interface. These results indicate that the roughened surface has two opposite effects, one to supply interfacial space for the PD streamers to crawl along the interface in case of small interfacial gap and other to become the restraint factor for PD streamer crawling along the interface in case of larger interfacial gap.

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Acid rain is the precipitation of pH lower than 5.6, of which the main features are ion concentration, acidity pH, and conductivity. As there exit a considerable variety of acid rains originated from different sources, the characteristics of acid rain are different in various industry areas. Although there have been some studies on the erosion effects of artificial acid rain on the insulating materials, the mechanism and extent of influences of ion concentration, pH, and conductivity of varied acid rain remain to be resolved. In this paper, the degradation effect of acid rain on the high temperature vulcanizing silicone rubber (HTVSR) insulator is investigated by the accelerated aging of artificial acid rain. The influences of ion concentration, pH, and conductivity of acid rain on the material structure, hydrophobicity, and surface discharge current of insulator are respectively studied. Experimental results reported here show that conductivity of acid rain mainly induces the tracking and discharge on the energized insulator surface, and the acidity pH affects the inorganic filler in silicone rubber. The erosion effect of acid rain on the energized insulator is more severe than that on the insulator without applying voltage. Variation of conductivity hardly has influence on the insulator without applying voltage. Although the insulator surface degrades with the increasing of ingredient concentration, when the ion concentration is too high, the degradation of insulator has a trend toward saturation. The ingredient concentration of actual acid rain exerts an insignificant effect on the degradation of silicone rubber insulator. Owing that the atom bond structure of Si-O bond in silicone rubber has a high band energy, silicone rubber insulator presents a large resistance to the varied acid rain.

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Incombustible and combustible metallic materials simulating low level radioactive miscellaneous solid wastes generated from nuclear power plants are simultaneously melted by thermal plasma heating with non-radioactive tracers in oxidizing atmosphere (air). The solidified products show the following excellent properties suitable for final disposal.
The uni-axial compressive strength of slag layers is more than 50 MPa in every combination of materials.
The concentration of cold tracers and specific gravity are homogeneous in both metallic and slag layers of solidified products. Therefor, it must be easy to measure radioactivity of the waste form before final disposal.
The results of leaching test show that the solidified products have performance good enough to stabilize the radionuclides.
The cold tracers show a stable migration into solidified products and even Cs with a low boiling temperature can be captured in the slag layers more than 50 %.
From the above results, we concluded that the plasma melting technology can be applied to simultaneous treatment of miscellaneous solid wastes.

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Degradation of the printed wiring board due to the ionic migration was evaluated by the measurements of capacitance (C) and tan δ between the conductors on the board in a frequency range of 0.6-1000Hz. The material of the insulating board used was fiberglass reinforced epoxy (Fr-4). The configuration of wiring conductor (Cu) on the board was designed according to IPC-SM-840. A distance between the conductors was 0.165mm. The endurance test was performed by applying DC70V to the conductors on the board, which was set in a chamber controlled at 85°C and 85%RH.In the low frequency region (_??_10Hz), C and tan 6 increase 800-1000h after the voltage application. After the detection of the increase, C and tan δ in the low frequency region fluctuate with the laps of time. The fluctuation for the low frequency region is much greater than that for the high frequency region (_??_60Hz). It is confirmed that the sudden increases in C and tan δ in the low frequency region coincide with an appearance of the migration on the insulating board between the conductors. Whereas in the high frequency region, the coincidence is unobserved. The migration in early stage can be detected by the increases of C and tan δ in the low frequency region, which will be due to the low mobility of ions in the water film on the board between the conductors. The ions in the water film may be Cu ions migrated from conductors.

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Composite insulation systems consist of different insulators and their systems are widely used in high voltage equipment and in power cables. These interfaces are the weak part of the composite and play a decisive role in the electrical treeing and dielectric breakdown processes of the composite. Therefore, it is important to study the effects of their interfaces on the electrical treeing of polymer/polymer composite insulators.
In this paper, we investigate the ac tree growth in the specimens having heat-adhesive interfaces between ethylene vinyl acetate copolymer (EVA) sheets and the other different polymer films. The polymer/polymer interfaces in our study are arranged as being parallel to the line of electric force. It is found that the characteristics of ac tree propagation in the vicinity of the polymer/polymer interfaces are considerably different at the combinations of different polymers.

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