An L=2 Helical Heliac is a newly proposed helical-axis configuration of Heliac type in which toroidal coils and a center conductor is replaced by L=2 helical coils with a double helix. The Shafranov shift of the magnetic axis in an L=2 Helical Heliac is suppressed as the helical displacement of a helical coil axis (HDCA) increases because of the increase in the rotational transforms. This suggests that the equilibrium beta limit is large for an L=2 Helical Heliac with a large HDCA. An L=2 Helical Heliac with a larger HDCA, however, has a no magnetic well, larger magnetic ripple and the smaller outermost surface. No magnetic well means that the stability beta limit of an L=2 Helical Heliac with a large HDCA is low because the magnetic shear of an L=2 Helical Heliac is not so large. The optimum coil parameter set of an L=2 Helical Heliac is presented from the standpoint of the equilibrium and stability beta limit.

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The reason how the constant current characteristics is realized in start-up stage power supply current, which is an advantageous factor in term of energy saving with in-phase type operating circuit for high-mercury arc lamp to conduct sine wave supply current with almost 100% of power factor is presented by way of harmonic balance method.

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A pulsed power generator with an inductive energy storage system has advantages in weight and size in comparison with a conventional pulsed power generator consisting of a Marx generator and a water capacitor. However, inductive pulsed power generators need opening switches which can interrupt a large current rapidly. Development of such repetitively operated opening switches has been expected for various applications. In this paper, development of an inductive pulsed power generator repetitively operated is described. Explosive wires, which have been studied for single shot machines, are used as an opening switch for this repetitive pulsed power generator. Explosive wires are successfully set automatically, and operated with 6pps (pulses per second). The reproducibility of output voltage was pretty well.

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In this work, the effect of discharge condition on the NOx reduction performances by a superimposing barrier discharge plasma reactor is experimentally investigated. The superimposing barrier discharge plasma reactor consists of double coaxial cylinders. The outer tube is made of Pyrex glass with aluminum foil electrode which is the outer electrode. The inner tube is a glass one filled with NaCl solution which is the central electrode, and nickel wire electrode wound on the surface of central electrode is the inner electrode. Amplified AC high voltage is applied to the outer electrode and central electrode, and the inner electrode was used as a common ground. A superimposing discharge is generated by surface or silent discharge of 50Hz and changeable frequency. Experimental investigation has been conducted to reduce NO concentration by two kinds of single discharges operating mode and three kinds of superimposed barrier discharge on the changeable frequency.
The results show that the reduction rate of NO at superimposed barrier discharge is higher than that of a single discharge at the same applied voltage. At the range of low discharge power, the highest reduction rate is obtained by silent discharge mode. However, the discharge power is more, the highest reduction rate is obtained by surface discharge mode.

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Non-thermal plasma reactors, and in particular surface, silent and superimposed barrier discharge reactors, have shown significant potential for removing NOx, CO2 and SOx emissions from the flue gas of thermal power plants, incinerators, and diesel engines. In the present work, the effect of moisture on the decomposition of NO2 at a reduce pressure 2.7kPa was experimentally investigated. The reactor is a coaxial discharge tube and consisted of strip-type and continuous electrodes mounted on insulating supports.
A 50Hz ac high voltage is applied between the electrodes and the current of the silent discharge is maintained at fixed voltage during the experiments. The initial gas and discharge by-products were measured using Fourier Transform Infrared spectroscopy. The experimental results show that the NO2 decreases with increasing humidity and residence reaction time, while NO, N2O and HNO3 appeared in the reaction products. The rate of NO2 reduction was fastest at an initial concentration of water vapour at 200mg/m3 with high oxygen concentration.

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We apply V-Q Lissajous' figure for the discharge measurements of ac PDPs (Plasma Display Panels) which have the electrodes covered with dielectric. From measuring the V-Q Lissajous' figure, we can know the wall voltage and the voltage between the discharge gap. We can also know the sparking voltage and extinction voltage. We compare the PDP discharge, which occurred at fast rise time applied voltage, and ozonizer discharge, which occurred at slow rise time applied voltage. Then we know that the discharge phenomena of PDPs, which sparking voltage is very high and extinction voltage is very small, is completely different from that of ozonizer discharge, which gap voltage is kept constant, the sustain voltage V*. From the point of view, we propose noble discharge model for ac-PDPs.

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We investigated surface discharge elongation phenomena on an insulated fine wire under the application of an impulse voltage in both of positive and negative polarities. In this study because the surface streamer was guided along a single linear discharge path, so the streamer elongated in one dimensionally on the wire. The streamer observed in this studies exhibit intermittent and stepping growth. Injection charge to the surface streamer was measured to clarify the mechanism of surface discharges. The backward discharge always occurs owing the existence of excessive charge injection process through the forward discharge. The backward discharge plays very important roles in the charge injection mechanisms, as it keeps total line density injected into the discharge to be nearly constant.

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The improving collection efficiency for particles smaller than l [μm] on every precipitator is important We sought to improve, the collection of these particles on an ESP due to particle agglomeration. Particles are charged by AC corona discharge at precharging section, and agglomerated at plate-plate electrodes section at downstream of precharging section.
Diesel exhaust particles (DEP) were used as particulate matter for the experiments. The distribution of particle size was measured using a particle counter and ascanning electron microscope. By these methods, particles as small as 0.01 [μm] could be counted. Result shows agglomeration between particles at AC corona discharge operating mode. The concentration of particles smaller than approximately 0.35 [μm] decreased and that of particles larger than approximately 0.35 [μm] increased by agglomeration. The agglomeration rate increased and saturated with increasing an applied voltage. These results may be due to the size distribution and decreasing characteristic of concentration by agglomeration.

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For development of the electrical appliances, analysis of a generated electro-magnetic field is required. As methods of the electro-magnetic field analysis, the Finite Element Method (FEM) and the Boundary Element Method (BEM) have been widely used. The FEM is suitable for analysis of a complicated region which includes non-linear materials. On the other hand, the BEM is useful for analysis of infinitely extending fields. To take full advantages of these two method, the authors have been proposing a hybrid FE and BE method to electro-magnetic field having non-linear and infinite subfields. The hybrid FE/BE method, however, requires a long calculation time for a large scale problem. To reduce calculation time for such problems using the hybrid FE/BE method, this paper proposes parallel processing scheme and evaluates its performance on Cenju-3.

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This paper presents experiments performed using a dielectric barrier discharge for mobile engine pollution control purposes. Measurements of NO, NOx decomposition efficiency and the resultant energy cost was achieved for sample gas mixtures (NO/N2, NO2/N2) and for real diesel engine exhaust gas. Experiment results show that a significant NO decomposition rate of 65-76% (in NO (=644ppm and 166ppm)/N2) can be obtained with the reactor used. The related energy cost was <300eV per NO molecule removed. Experiments in NO/N2 also demonstrated that varying the power injection into the reactor lead to a considerable reduction of the energy cost while keeping high decomposition rate. With diesel exhaust gas, 66% of NO. decomposition (initially 115ppm) was achieved for an energy cost of 464eV/NOx.

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Degaradations with water boiling were explored by Acoustic emission mesasurement for tensile and bending tests of epoxy composite filled with silica particles. Mixing of silan coupling agent (SCA) improved the adhesion between epoxy resin and silica particles of epoxy composite after immersing in water boiling Amplitude distribution of Acoustic emission measurement indicated at high amplitude in mechanical testing for SCA mixing composite.

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In this paper, we made the simultaneous measurements of DC electric strengths and space charge distributions in a 100μm thick low-density polyethylene (LDPE) films up to electrical breakdown by using pulsede lectroacoustic method. Here the cathode and anode electric field modified by the accumulated space charges in front of each electrode were estimated from the measured charge density at the cathode and the anode, respectively. The sample film was placed in the iron sphere - aluminum plane electrode system and the DC step voltage increased 2kV and 5min. was applied to the film up to the electric breakdown.
The electric strengths of LDPE film decreased with temperature and electric strengths at aluminum cathode was lower than that at iron cathode, suggesting that the carrier injection from the electrodes play some role in the DC breakdown. At room temperature, both the cathode and the anode electric fields were nearly equal the applied electric field at the breakdown, showing the little space charge accumulation in the bulk With increase of temperature, the cathode electric field decreased and kept the value almost equal to the average electric field, while the anode electric field were higher than applied electric field before the electrical breakdown. The above results suggest that both the negative carrier injection from the cathode and the hetero space charge accumulation near the anode affect the DC electrical breakdown of LDPE film at higher temperature.

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SiC (silicon carbide) ceramic is a promising candidate semiconductor material applicable to electronic devices operated at high temperature such as the thermistor. Effects of the aluminum addition on the microstructure and the electrical conductivity of SiC ceramic were investigated. SiC ceramic added aluminum in the quantity range from 0wt% to 0.6 wt% were fired at 2273K for 30 minutes. The thermoelectric power, DC conductivity and AC conductivity were measured for these SIC ceramics. The samples showed P-type behavior independent of the amount of aluminum addition. As the amount of the aluminum addition increases, the electrical conductivity of the SiC ceramic increased while its temperature and frequency dependence decreased. It was revealed that the conductivity and the temperature dependence of the conductivity of the SiC ceramic can be controlled by the varying the amount of aluminum addition, which expand the chance of the material design.

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To improve on superconducting characteristics of oxide superconducting thick films, multilayer deposition process in KrF excimer laser ablation method is used to prepare YBCO thick films on MgO and LaAlO3 substrates. Laser fluence, laser repetition rate and substrate temperature were changed at substrate interface deposition (thickness: few run), intermediate layer deposition (thickness: about 300nm) and surface layer deposition (thickness: about 600nm) for both substrates and were optimized in each deposition periods.
In case of using the MgO substrate, strict deposition conditions for each deposition layers were required, particularly related to substrate surface deposition conditions. YBCO (1μm)/MgO thick film prepared under the optimized growth conditions showed a smooth surface and c-axis textured growth. The superconducting propperties of Tc=89.2K and Jc=1.2×106A/cm2 (5K) were obtained.
On the other hand, the broad optimum conditions for YBCO (1μm)/LaAlO3 is easily to produce same quality YBCO films. However, superconducting properties were degraded with increase of thickness in spite of use of multilayer deposition process.

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SrBi₂Ta₂O₉ thin films were successfully prepared at a low annealing temperature using a low oxygen concentration annealing technique. It was possible to obtain a single perovskite phase at 600°C in 0.7% oxygen concentration and fluorite phase was observed at 600°C in 100% oxygen concentration. In addition, the SrBi₂Ta₂O₉ thin films annealed at 650°C in 0.7% oxygen concentration were well crystallized and composed of densely crystal grains with the size of 70nm. The remnant polarization and leakage current density of the SrBi₂Ta₂O₉ thin film obtanied using this new technique were 7μC/cm2 and 3×10-9A/m2 (at 5V), respectively. The final remnant polarization after 109 switching cycles was nearly constant.

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We have measured the variability of thermoelectric performance for p-type Bi-Sb-Te thermoelements, synthesized via the PIES (Pulverized and Intermixed Elements Sintering) method. We observed variations both between samples and between slices taken from individual samples. Within each sample, resistivity and thermal conductivities were found to vary by 3 to 4% along the sample length, with minimum in the center; while the Seebeck coefficient varied by 1% randomly.
Variability in thermoelectric performance was larger between samples, due to variances in carrier concentration (not measured). The observed thermoelectric figure-of-merit had a mean value across ail sarnples of. 00315±.00022±.00019 K-1; where the first error is due to variance between samples, and the second error is the variance within each sample. This yields a TOTAL VARIABILITY of 10%. Thus, the PIES method is an excellent choice for high quality mass production of p-type Bi-Sb-Te.

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