We developed a potential monitor to measure the surface charging potentials on insulating materials for spacecraft due to charged particles in space environment. The potential monitor was installed on geostationary Engineering Test Satellite V of Japan which was launched on August 27, 1987. Three kinds of thermal control materials were used as samples. We obtained the following observational results: (1) The level of the charging potential depended on the environmental plasma condition and the material. (2) The rapid increase of the charging potential to be due to the shadows of the paddle and/or the antenna was occasionally observed. (3) For long time, the potential gradually increased under the shaded condition, but decreased in the sunlit condition.

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This paper describes transmission electron microscope (TEM) analysis of polyethylene in terms of electron energy loss spectroscopy (EELS) in order to evaluate the mean free path of high energy electrons. The mean free path is one of the basic properties due to pylyethylene-electron interactions and is useful to characterize the material. The mean free path was correlated with polyethylene specimens with various mean density. For the first step, the mass thickness (the relative thickness to the mean free path) was evaluated through EELS data and then the real thickness of the specimens was measured by the side view of the specimen through TEM observation. Finally, the mean free path in polyethylene was evaluated to be about 500 nm at electron energy of 200 keV with an electron beam radius of 10 nm. The mean free path slightly depends on the specimen density.

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Recently, high-speed digital communication with large capacity is the social requirement. The frequencies of the CPU clocks in personal computers and workstations are getting higher rapidly. On the other hand, the integration technology of integrated circuits has been developed, and this makes the electronic application more miniature and higher density. These tendencies are principal factors which enlarge the crosstalk. Therefore, it is important to study the cause of crosstalk and to suppress it.
In this paper, we study the behavior of crosstalk of microstrip lines with nonlinear loads such as CMOS-IC. To simplify the analysis, we use the 4-port network. Experiment shows that the CMOS-IC can be regarded as a linear load in high frequency range.

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The investigations on dc tracking resistance should be enhanced due to the increasing of organic insulating materials being used with dc power. This paper describes the influence of gamma-rays irradiation on dc tracking failure of organic insulating materials by use of the IEC Publ. 112 method. Epoxy resin, polyethylene terephthalate and modified polycarbonate which were irradiated in air until 1×10⁵ Gy and 1×10⁶ Gy with dose rate of 10⁴ Gy/h using a ⁶⁰Co gamma-source have been used as the test samples. The total dose effects on the number of drops to tracking failure (or erosion depth), and scintillation discharge energy have been studied. The effects of gamma-rays irradiation on do tracking failure are due to radiation-induced degradation or cross-linking of organic insulating materials. A wavelet analysis using gaussian wavelet is applied to show the scintillation discharge energy.

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This paper describes the hydrophobicity variation of an alumina-trihydrate filled silicone rubber during a water absorbing-drying process. Especially, the hydrophobicity recovery characteristics during the drying process am investigated. It is found that the hydrophobicity can not recover the initial property after long-term water immersion because alumina-trihydrates expose on the surface and low molecular weight contents migrate into water. The effect of thermal ageing on the variations of the water absorbance and the hydrophobicity is also investigated. It is found that water absorbance of the thermally aged is higher than that of the untreated. In addition, it is turned out that the hydrophobicity recovery characteristics of the thermally aged depend on the heat treatment temperature.

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Hirokazu Tohya, Member (Resources and Environment Protection Research Labs., NEC Corporation) Discrete wavelets transform is widely used for the wave and image analysis. Particularly, multi-resolutional analysis is extremely useful tool for the noise reduction. On the other side, electromagnetic field coming from the printed circuit boards (PCB) is becoming one of the noise sources according to the rising up the operation frequency of central processing unit (CPU). In order to reduce the noise coming from PCB, it is extremely important to grasp the dominant current distributions on the PCB.
In the present paper, we apply the discrete wavelets analysis to the noise reduction of the current vector distributing on the PCB. Numerical and practical examples demonstrate that the noise current vectors are dramatically removed by our approach.

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Barium strontium titanate ((Ba_xSr_1-x)TiO₃) thin films have been successfully prepared in situ on Al/SiO₂/Si(100) or SiO₂/Si(100) substrate by backside deposition using intense, pulsed, ion-beam evaporation technique, without heating the substrate. The deposition rate of 20nm/shot is obtained. The composition ratio of the films is same as that of the target in structure of cubic perovskite polycrystals. The relative dielectric constant of the film deposited at composition of x= 0.5 is typically 43 at 100kHz.

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Induced current density in human head involved in generation of magnetophosphenes is estimated by numerical analysis using the impedance method to gain insight into the mechanism of magnetophosphenes. Complex shape and electrical heterogeneity of real human head are considered and a magnetic field which can cause magnetophosphenes is used. Calculated current density distributes throughout the head and is relatively high around nose and eyes. Induced current density distribution on retina is higher in the upper and lower parts than in the central part, which is consistent with experimental observations. Maximum induced current density at retina is estimated about 11mA/m².

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Darkening Phenomena of electroluminescent (EL) lamps with polyethyleneterephthalate (PET)/indium tin oxide (ITO)/ZnS:Mn/BaTiO₃/Al structure has been investigated under operating in the field. The field test over one year operation changes the EL lamp surface to darken. In addition, the PET film peeled off from the underlying ITO layer. The results of Auger electron spectroscopy (AES) indicate that after the field test a sulfur-rich layer piles up at the boundary between PET and ITO films. The darken color of the film becomes disappear after etching off the most part of ITO film, then an original color of underlying ZnS:Mn layer appears. The chemical state change of the ITO and the stoichiometric change of the ZnS:Mn are also observed after the field operation of the EL lamp. The results indicate that the darkening of the EL lamp is mainly originated to a selective out-diffusion of sulfur of ZnS:Mn layer into ITO film and the chemical state change of the ITO under the EL lamp operation.

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New Low Density Polyethylene (M-LDPE) prepared using metallocene catalyst has narrower composition distribution and molecular weight distributions than Linear-Low Density Polyethylene (LLDPE) using Ziegler catalyst. The authors compared the electrical insulating properties of M-LDPE films and conventional LLDPE films. The high-field current of M-LDPE was found to be lower than that of LLDPE. The difference in current increased with the decrease of temperature. The high-field current was much suppressed in M-LDPE with a low melting point. The impulse breakdown strength of M-LDPE raised with the decrease of temperature. The insulating properties of M-LDPE with a low melting point were improved at 30°C. These results were explained by a fact that M-LDPE with a low melting point includes more low-molecular-weight components. We also discussed the effects of antioxidant on the electrical properties of MLDPE. We compared the electrical conduction and breakdown strength of undoped M-LDPE and antioxidant-doped M-LDPE. The difference of their electrical properties were little. It was found that the excellent properties of M-LDPE do not depend on the effects of antioxidant.

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Effects of internal oxidation on the buried silicon dioxide have been studied. The dioxide examined was the buried insulator in a silicon-on-insulator (SOI) structure fabricated by implantation of oxygen ions into Si, or the SIMOX process. The internal oxidation is an oxidation process given to the SOI structure after its fabrication. It was observed that the photoluminescence intensity due to neutral oxygen vacancies (O₃≡Sii≡O₃, "≡" denotes bonds with three separate oxygens) increased after the internal oxidation. The oxide thickness and the number of E' γ centers (O₃≡Si•, "•" denotes an unpaired electron) were also found to increase similarly. The measurements repeatedly done by changing the oxide thickness revealed that the increased part of oxide by the internal oxidation contains the vacancies with a similar density to the original part. It is concluded that the internal oxidation scarcely affects the oxygen deficiency of the oxide. It was also observed that the number of breakdowns at low electric fields remarkably decreased after the internal oxidation, indicating that electrically weak spots such as silicon pipes were effectively reduced.

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The electrochemical properties of fly ash obtained from combustion of fuel in fossil power plants and their performance as anode material of secondary battery have been investigated. Various fly ash pellets molded at various molding presssure have been used as anode in lithium secondary battery. The best performance was achieved when fly ash pellet molded at pressure of 100kgf/cm² is utilized, that is, charge capacity of 273Ah/kg and Coulombic efficiency of larger than 95% have been achieved In addition, this battery exhibited good cycling performance. Considering these results, we predicted that utilization of the fly ash as anodematerial and polyaniline conducting polymer as cathode material in a secondary battery will show charge capacity of 101Ah/kg, energy density of 365Wh/kg and Coulombic efficiency of higher than 92%. Potential application of fly ash as anode material in the secondary lithium ion battery seems also to be meaningful from view point of evironmental improvement by reducing harmful waste.

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The growth process of silver dendrite due to ionic migration on glass substrate has been studied by confocal laser microscope. The migration between screen-printed silver electrodes with gap of 0.5mm was occurred both under the condition of 25°C, 98%R.H, and in the de-ionized water, The results were analyzed by the dimentionality of fractal natures of the dendrite growth. The area S of dendirte increases with time t according to S=t_Dt, where a factor Dt is approxiately ranging from 0.4 to 4.4. The shape fractal demension of dendrite (Ds) is approxiately ranging from 1.5 to 1.8. We show that a failure time can estimated from Dt, Ds and an unisotropic ratio of dendrite growth.

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In this paper we researched on the implementation of the welfare information system on the Internet. We pointed out the following three considerations that are need to the welfare information system. 1) The systems can deal with multi-media data. 2) We can do interactive communication with others. 3) Users can share much useful information on welfare. Then we designed the model of the welfare information system that consists of four sub system (two databases for public and for managers, a consultation service system, and a discussion system). It can deal with five kinds of welfare information (information on service, need, treatment, participation, and management). Moreover, it is necessary to design the system based on the concept of "universal design". After the implementation of the system on the Internet, we experimented the use of the system in three months for a welfare association for the visually impaired, analyzed the traffic within the system, and evaluate the effectiveness of the system use.

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A method to simultaneously measure the electrical and magnetic properties of a spherical sample (SRPM method) has been developed. The SRPM is the acronym of "Simultaneous Resistivity and Permeability Measurement" for a normal metal sample. With the SRPM method, a rather time-consuming full formula is used to calculate the difference in the impedance of a coil with, and another one without a sample. A new simplified formula for this purpose has been derived. Comparison of the values obtained with the full formula and the new one was made. The new simplified formula cuts down the calculation time to one tenth. As the new formula is based on the case when the sample is placed in a uniform magnetic field, the applicable region of the new formula is shown in comparison with the full formula.

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We developed a corona reactor, a new gas purifier without liquid nitrogen, to remove gaseous impurities from the excimer laser gas, because the impurities from the discharge affect the laser output power negatively. The electrodes of the corona reactor are arranged to co-axial construction, where a cylindrical tube is used as an anode electrode and a wire cathode is set at the center of the cylindrical anode.
This paper describes the experimental results of the corona reactor under the practical excimer laser operation. The corona reactor was run to efficienc tests for 6×10⁸ shots of excimer laser pulses. During the long operation, the reactor removed the impurities well so that laser output power went down as little as the case of the conventional gas-purifier with liquid nitrogen. The electrical characteristics of the reactor showed no degradation during the experiments.

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We measured the electron transport coefficients, the electron drift velocity W and the product of the gas number density and the longitudinal diffusion coefficient NDL, over the E/N range from 0.03 to 100 Td and gas pressure range from 0.133 to 122kPa in the 0.526% and 5.05% C₃F₈-Ar mixtures by the double shutter drift tube with variable drift distance.
We determined the electron collision cross sections for the C₃F₈ molecule by the comparison of the present measurement and the calculation of electron transport coefficients in the C₃F₈-Ar mixtures by using a multi-term Boltzmann equation analysis. Our special attention in the present study was focused upon the vibrational excitation cross sections of the C₃F₈ molecule.

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We analyzed the electron arrival time signal measured in pure oxygen and in dilute oxygen-argon mixtures by using a double shutter electron drift tube with variable drift distance and derived the density normalized attachment coefficient for respective gases. The present attachment coefficient detennined for pure oxygen agreed well with previously reported values and we confirmed that the present apparatus was useful in determining electron attachment coefficient even if there were no ionization, when there will be no steady state current growth and, hence, the steady state Townsend (SST) method can not be applied in principle. The measured attachment coefficients in the mixtures agreed very well with the calculation using our latest cross section set for the oxygen molecule and that will be a confirmation for the validity of the cross section set.

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In this paper, the propagation characteristics of a creepage discharge on the surface of a solid insulator with a back electrode in perfluorocarbon liquid under an impulse voltage application are investigated. The propagation process is observed in detail by using a high-speed schlieren optical technique, and simultaneously waveforms of a current and a charge are also measured. Consequently, the polarity effect of the streamer propagation and the positive streamer which propagates stepwise can be seen. The latter is concurrent with the sparse current pulse which corresponds to the charge step-variation. These results are compared with ones obtained in transformer oil.

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NO reduction has been studied by using a barrier discharge in NO/N₂. The rate of NO reduction depends on applied voltage, pulse frequency, input power, gas flow rate, and initial NO concentration. Experimental results satisfy a scaling relation in which the rate of NO conversion rate is determined by input energy per flow rate and NO initial concentration. A simple calculation for reaction processes shows that, for this relation, NO conversion rate is determined by generation of N by discharge. At constant voltage and current waveform, NO conversion through barrier discharge can be normalized by the relation. While discharge volume and polarity are not included the parameters of the scaling relation but affect the efficiency of input energy into the discharge tube. The scaling relation can be used to estimate the dependence of efficiency on the structure of discharge tube and power supply.

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