This study presents a new theoretical model for discribing a rectilinearly channeled negative discharge generated on PET film (δ=50μm) under atmospheric conditions. The channel is modeled using a RC distributed constant circuit with the front potential Vl and moving at propagation speed υl.
A conduction equation (∂U/∂t=μ√U ∂2U/∂2z, U=V2, with V; Potential and μ; electron mobility) is introduced under the assumption that the generated current consists of only electrons. This equation can be solved using the boundary conditions and speed condition in which the speed is considered as being proportional to the gradient of U. (υl=-β∂U/∂z, β; const)
Although it is difficult to solve the conduction equation analytically under the boundary condition and the speed condition, using the simplified boundary condition and the length l (t) instead of the speed condi- tion, the conduction equation is solved numerically. And the U (z, t) are caluculated and compared with the experimental results.
I proposed that one of the best approach to the discussion of the conduction equation is using the solution of Stefan problem which corresponds to the fusion phenomenon occuring in a column of ice. The solution of Stefan problem are also compeared with the above numerical solution.

抄録全体を表示

This paper deals with an analysis on the offset pressure change of a Spinning Rotor Gauge (S R G), which caused from thermal change in a stainless steel rotor in starting operation and in real measurements. This analysis method is recognized to have practicability and validity in this analysis that were usefully applied to select the physical characteristics of the rotor such as density, specific heat, linnear expansion coefficient and emissivity. Then, it begins to investigate to these measured physical characteristics of rotate materials that involved liquids with measuring method of containerless treatments. Then, it continues to investigate another factor of offset pressure that especially, occurs in the effect of eddy current damping.

抄録全体を表示

The author has developed the concept of a novel ozone generator that adopts the O/O₃ different-space-generation system. The novel ozone generator consists of a dissociation chamber, an ejector, and an ozone formation chamber. Oxygen atoms generated from pure oxygen as the first material gas in the dissociation chamber are mixed with air as the second material gas in the ejector, and react with oxygen molecules to form ozone molecules in the ozone formation chamber. It has a high O₃ formation efficiency only in the low O₃ concentration range. For the improvement of the novel ozone generator, the author has newly proposed the concept of a O/O₃ different-space-generation system with a multi-stage reaction process. It consists of a dissociation chamber, multiple ejectors, and multiple ozone formation chambers. The oxygen atoms from the dissociation chamber are divided into parts for every stage and added to the air or the air containing O₃ at every stage. The ozone concentration is accumulated in every stage, and reaches the expected value in the last stage. According to the simulation results, the newly proposed ozone generator can generate O₃ of 3.1mol% with an efficiency of 172g/kwh. The novel ozone generator with the O/O₃ different-space-generation system has been improved to have a high O₃ formation efficiency even in the high O₃ concentration range.

抄録全体を表示

The pulsed electroacoustic (PEA) method and the piezo-electrically induced pressure wave propagation (PIPWP) method are compared. While the PEA method has been widely used as a measurement technique to observe space charge distributions in solid dielectric materials, the PIPWP method has not been widely used because of its relatively lower spatial resolution as compared to that of the PEA method. Therefore, in this research, an attempt has been made to improve the resolution of the PIPWP method. In this paper, principles of the generation and the detection of pressure waves in both PEA and PIPWP methods are summarized. Furthermore, the two methods are compared through observations of the generation, drift and trapping of carriers in an organic photoconductor (OPC).

抄録全体を表示

The mechanism of boron nitride thin film formation using the nitrogen-argon gas mixture plasma jet which is a new method reported by our previous paper has been studied. The electron temperature, electron density and the magnitude of various ion and radical species in the plasma jet have been measured by the electrostatic probe and the optical spectroscopic methods. The amount of recombination of nitrogen free atoms by three body conversion was estimated using the emission intensity of first positive band system from the nitrogen B state vibrational level of v=11. The emission intensity from vibrational level of v=11 at vicinity of the boron target increases more than one order of magnitude larger than that when the boron target is absent and has a peak value at the gas pressure approximately 5 to 10 Torr. Experimental data were discussed in connection with the optimum discharge condition of BN synthesis in the plasma. It is concluded that the enhanced recombination on boron target and substrate surface supplies large amount of molecular nitrogen ions and vibrationally excited nitrogen molecules in the vicinity of the substrate and thus, the high energy ion rich condition makes it possible to form c-BN film on the substrate surface placed in the plasma jet.

抄録全体を表示

Thermally stimulated current in polymethylpentene (PMP) was found to have peaks at about 20°C (referred to as δ peak), 80°C (γ), 110°C (β), and 150°C (α). From the activation energy value or the dependence on biasing electric field, δ peak is considered to be attributable to dipolar depolarization of polar groups caused by glass transition. While carbonyl groups of ester form existing in antioxidants seem to be mainly responsible, hydroperoxide or carbonyl groups formed by oxidation can also contribute to δ peak. The γ peak is caused by the movement of electrons to the electrode from which they were injected. Both β and α peaks seem to be attributable to the motion of hetero space charges.

抄録全体を表示

Recently the attention has been paid to low frequency electromagnetic environment. In this paper, effects of phase differences of the magnetic field components on the induced current density in a homogeneous spherical human model exposed to 60 Hz horizontal and vertical magnetic fields have been discussed. First, the effect of phase differences of the magnetic fields on induced current density is remarkable in case those magnitudes are approximately equal. Second, the distributions of the induced current density in the model have been visualized, and it is found that on the special conditions there are points where no current flows in the model and the maximum value exists on the circumference of the surface of the model. Third, the induced current density in the spherical model exposed to magnetic fields under the transmission line becomes maximum at the tower center line and the rnaximurn value depends only on vertical magnetic field because of phase differences of magnetic fields. These results showed that the phase differences of the magnetic fields have an effect on the induced current density in the model exposed to the ordinary magnetic environment. Therefore the discussion on the phase differences of the magnetic field is useful for analysis of induced current density in human exposed to a 3-dimensional magnetic field.

抄録全体を表示

In-situ monitoring of film quality of the diamond film during growth by hot filament-assisted CVD method is made. The CVD diamond film including non-diamond carbon was grown under the condition where the current flows between a filament and a substrate. On the other hand, the almost pure CVD diamond film was grown under the condition where no current flows between a filament and a substrate. The intensities of thermoelectron emission and secondary electron emission from CVD diamond including non-diamond carbon are higher than those from CVD diamond films including nondiamond carbon. Defect density with lone-pair electron in CVD diamond films including nondiamond carbon was about five times higher than that of the pure CVD diamond films. It was suggested that electrons mainly emit from lone-pair electron defects on the surface of CVD diamond films including nondiamond carbon.

抄録全体を表示

The outdoor polymer insulating materials are exposed to UV-ray, one of the most severe ageing factor for the polymeric materials, in natural environment. Therefore, it is suggested that UV-ray induces the surface chemical structural change with the long-term outdoor use, which makes their electrical insulating performance such as the tracking resistance decrease. After the UV-ray irradiation to samples, the tracking resistance, surface hydrophobicity, surface appearance, microscopic surface appearance and surface chemical structure are compared with these of the original. EVA, Silicone Rubber, Modified Silicone Rubber, Flame-resisting Modified Silicone Rubber, Epoxy and Silicone Resin Coating are investigated. The experimental results show that the tracking resistance decreases and/or increases due to the UV-ray irradiation. From the results of surface chemical analysis by FT-IR spectrometer and X-ray diffraction analyzer, the possible chemical reactions induced by UV-ray are considered. Then, it is found that the decrease in the tracking resistance results from the surface chemical structural change of the base polymer. The recovery of the tracking resistance is attributed to the remarkable loss of the surface hydrophobicity, which concerns the contaminant flow form and discharge behavior on the surface.

抄録全体を表示

Time variation of receding contact angle on the surface of silicone rubber pieces and that of weight of them were investigated, which had been immersed in water. It was shown that reduction in hydrophobicity in a short time range is an temporal phenomenon. However, repetitive immersion or acceleration by using water at elevated temperature proved that hydrophobicity on the surface of specimens was lost gradually. Time variation of weight of specimens suggested that a certain component like low molecular silicone migrates from the bulk of specimens to their surface.

抄録全体を表示

The authors prepared the low density polyethylene (LDPE) films with densities of 0.917-0.927g/cm³, and discussed their high-field conduction and electrical breakdown above room temperature. We discussed high-field conduction and electrical breakdown against film density. The high-field current of the specimen with a lower density was higher than that of the specimen with a higher density. In addition, the breakdown strength of the former is lower than that of the latter. The density dependence of impulse breakdown strength was lower than that of dc breakdown strength. The breakdown strength depends on the value of high-field current. The breakdown strength of the specimen with a higher current is relatively lower than that of the specimen with a lower current. In spite of the small difference in density, 0.01g/cm³, a big difference in dc breakdown strength, about 2MV/cm was observed. Our data showed the stronger density dependence of breakdown strength as compared with the previously reported data. Our experimental result also supported that the conduction pass in which high-field current flows mainly in forward in the amorphous region and that the breakdown of LDPE above room temperature was caused by an thermal breakdown process.

抄録全体を表示

Effects of fixing by shrink fitting on magnetic properties of iron coros are investigated to simulate magnetic behaviors of iron cores fixed in motor flames. Shrink fittings, of course, decrease their permeabilities and increase effective magnetostrictions and magnetic losses. It is well known that the magnetostriction increment and the permeability decrement are explained with the increase of magnetoelastic energy due to compressive stress by shrink fitting. The magnetic loss increases, however, cannot be explained with this energy. We show experimentally that the magnetic loss increases are occurred from the mechanical work due to the magnetostrictive movement of iron core under the compressive force.

抄録全体を表示

The present contribution demonstrates how the magnitudes and phase angles of the induced electric field in human model placed in the real non-uniform magnetic field differ from those in the ambient magnetic field supposed to be uniform. In the numerical calculation, a simple elliptical human model made of homogeneous substance is employed and so-called "Impedance Method" is used to analyze the induced electric field in the human model.
Examination of the results obtained for the single line shows that the magnitude of the induced electric field in the model will be in general under-estimated if the real non-uniform magnetic field would be supposed to be uniform. It is indicated that, under such a magnetic environment, the difference in the magnitude of the induced electric fields (δ_E) is almost directly proportional to the degree of the magnetic field non-uniformity (δ_B), and δ_E is always smaller than δ_B; i.e. the induced electric field strength is insensitive to the nonuniformity of the ambient magnetic field strength. As long as the magnitude of the induced electric field is concerned, almost the same conclusion as in the case of the single conductor can be drawn for the magnetic field environment appearing under the EHV and UHV transmission lines. In such an environment both the magnitude and phase angle of the magneflc field spatially vary. It is found that relationship between δ_B and δ_E is almost independent of the layout and geometrical configuration, and the line voltage of the transmission lines investigated. On the other hand the differences in the phase angles of the induced electric fields are found to be equal or greater than those of the external magnetic fields, depending on the field component to be concerned. It is consequently concluded that the phase angle of the induced electric field is much more sensitive to the non-uniformity of the ambient magnetic field than its magnitude.

抄録全体を表示

AC surface PDs in air from a triple junction (TJ) of cylindrical insulator with a backing electrode were decreased by a use of the hollow type electrode. The voltage applied was changed in a range from 1 to 1.5 times of an initiation of PD (Vpd). The thickness of the insulator was changed in a range from 2mm to 7.5mm. In the cases of 1.2x(Vpd) of the applied voltage and 7.5mm of the thickness, the integrated magnitude of the PD pulses for the electrode with hollow was about 80% smaller than that for the electrode without hollow; the integrated number of the pulse event was 40-50% smaller than that for the one without hollow; the PD pulses of which magnitude was stronger than approximately 7×10^-1 C were suppressed significantly. The computing calculation of an electric field around the TJ suggested that the generation and propagation of the PD pulse resulted from the increase in potential and strength of the vertical field component on the surface of an insulator near the TJ. It was observed from dust figures that the propagation of PDs on the insulator with the hollow was controlled their length about 50% shorter than that on the insulator without the hollow.

抄録全体を表示