Superconductive single flux quantum (SFQ) circuits, which perform their circuit operations by controlling propagations of flux quanta in connected superconducting rings, can operate at the frequency of several tens GHz with ultra low power dissipation. The SFQ circuit is thought to be an attractive candidate for fundamental elements of future high-end information processing systems. This paper reports the development of SFQ microprocessors for high-end computation systems.

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This paper investigates methods of implementing a high-precision AC voltage control circuit using a transformer. An investigation was also made of the relationship between excitation parameters and the self-inductance of the winding as apparent to the excitation winding of the transformer. Concretely, the authors first demonstrate that the B-H loop apparent to the excitation winding varies with excitation parameters, and propose an approach for handling self-inductance. The proposed approach was applied to the analysis of an AC voltage control circuit, with the result that the calculated and actual controlled voltages were within ±0.15% error of each other. Based on these results, guidelines were developed for the handling of self-inductance when designing AC voltage control circuits with transformers.

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In this paper, characteristics of restoring force and braking torque for a passive magnetic bearing which has a rotation ring and a the permanent magnets were studied. The restoring force increases with the rotation speed and the ring displacement. On the other hand, the braking torque is saturated with respect to the rotation speed and is constant regardless of the ring displacement. In order to improve the characteristics of the magnetic bearing, we proposed auxiliary magnet for changing distributions of the magnetic flux and the current density on the ring. As a result, the braking torque is decreased by 27% and the restoring force is increased by 30%.

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In superconducting coils, local and excessive joule heating may give damage to the superconducting windings when a quench occurs and therefore it is essential that the quench is detected quickly and precisely so that the coils can be safely discharged. We have presented a quench protection system based on the active power method which detects a quench by measuring the instantaneous active power generated in a superconducting coil. The protection system based on this method is strong against the inductive voltage and noise which may cause insufficient quench recognition. However, the proposed system is useful for a single coil but it is vulnerable to the magnetically coupled multi-coil such as high field superconducting coils. Because the proposed system can not avoid insufficient quench recognition by the mutual inductive voltage from the other coils. This paper presents a method to improve the characteristics of the active power method by cancelling the mutual inductive voltage. The experimental results of the quench protection for small Bi2223 coils show that the proposed system is useful for the magnetically coupled coils.

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This paper describes an e-learning system for technical Chinese that integrates sounds, pictures, videos, and Flash animation into a Web-based multimedia course to optimize learning efficiency. The design employs an ADDIE model in instructional design and cognitive theory of multimedia learning.

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Parallel operation of pulsed plasma generated inside bubbles is successfully demonstrated by applying fast rising voltage to a multi electrode system mounted in treat water. A 10 ppm acetic acid which is not decomposed by ozone is used as persistent materials in water and the decomposing efficiency of that material is evaluated by measuring TOC values in water. The electric conductivity of treat water affects the decomposing efficiency because the water resistor that is inversely proportional to the conductivity limits the plasma current flowing along the surface of bubbles that are generated by feeding oxygen gas. With nine parallel electrode system, the decomposing efficiency of acetic acid shows higher values than that with a single electrode system. The emission of OH radicals generated in plasma was observed by spectroscopic measurements.

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Decomposition characteristics of acetone in a DC corona discharge generated between a multi-needle and a plane electrodes in nitrogen-oxygen mixtures at atmospheric pressure are investigated mainly by infrared absorption spectroscopy in this work. It is found that CO₂, CO, CH₄, HCHO, HCOOH and HCN are the by-products of acetone in the corona discharge, and that CO, CH₄, HCHO, HCOOH and HCN are intermediate products, which tend to be decomposed in the corona discharge. CO₂ is found to be the major and end-product. It is also found that acetone is chiefly inverted to CO₂ via CO at high oxygen concentration (20%) and via CO and CH₄ at relatively low oxygen concentration (0.2%), in addition to the direct conversion from acetone to CO₂. As the oxygen concentration increases, the percentages of carbon atoms contained in deposit on the plane electrode and the wall of the discharge chamber increases. Further, the decomposition process of acetone is deduced from the examination of rate constants for the reactions in the gaseous phase.

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Raman scattering from metastable excited nitrogen molecules N₂(A³Σ_u⁺) created by an impulse discharge in nitrogen at atmospheric pressure was detected. A pulsed Nd:YAG laser of wavelength 266 nm was used as the light source, and Raman scattering from N₂(A³Σ_u⁺) at wavelength 277 nm was detected using an interference filter and photomultiplier tube. The filter had sufficient rejection of Rayleigh scattering of laser light at wavelength 266 nm and Raman scattering from ground state nitrogen molecules N₂(X¹Σ_g⁺) at wavelength 284 nm. The temporal variation of the signal intensity of Raman scattering from N₂(A³Σ_u⁺) was measured by transmitting the laser at different time delays relative to sparkover. Results showed that the signal intensity decayed with a time constant of about 200 μs.

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We have developed a novel non-destructive optical diagnosis technique for low-voltage cable insulations used in nuclear power plants. The key features of this diagnosis are the use of two wavelengths to measure the change in reflective absorbance (ΔA_R), the use of polarized light to measure crystallinity and the use of element volatilizing to measure fluorescence. Chemical kinetics is used to predict the lifetimes of the cable insulations. When cable insulations darken and harden by time degradation, the ΔA_R and depolarization parameters increase. This means that the cross-linking density in the cable insulations increases due to deterioration reactions. When the cross-linking density of insulation increases, its elasticity, corresponding to the material's life, increases. Similarly, as the crystallinity increases due to the change in the high-order structure of the insulating resin caused by irradiation, its elongation property decreases. The elongation property of insulation is one of the most important parameters that can be used to evaluate material lifetimes, because it relates to elasticity. The ΔA_R correlated with the elongation property, and the correlation coefficient of an accelerated experiment using model pieces was over 0.9. Thus, we concluded that this optical diagnosis should be applied to evaluate the degradation of cable insulations used in nuclear power plants.

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Tracking of a cord plug caused by leakage current flowing between its electrodes, which is observed under contaminated and wetted conditions, is attributed to one of the causes of fire accidents. Demands of society for establishment of countermeasures against this type of tracking have become stronger since the number of fire accidents by the tracking has been increased in the recent ten years. However, it seems rather difficult to detect the leakage current because its magnitude is much smaller than that of a typical load current of a household appliance.
In this paper, a novel method to detect the existence of the leakage current is proposed, where a high frequency signal superimposed on a load current is detected instead of detecting the leakage current itself. It was confirmed by laboratory experiments that the signal could be detected only when wetted dust was in the space between a cord plug and an outlet. The proposed method seems promising to detect of tracking of a cord plug with high frequency signal.

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Electrostatic precipitators are used in decontaminating polluted gases in expressway tunnels in order to improve both driver safety and the environment around the tunnels. A conventional electrostatic precipitator has high collection efficiency but is still needed to improve collection efficiency for nano-particles smaller than 0.1 μm. The experiments carried out in this study have focused on improving nano-particle collection efficiency without using additional energy. The experimental electrostatic precipitator was a two-stage type consisting of a pre-charger and a collector. The collector had a parallel-plates configuration, including a grounded electrode and a high voltage electrode. A hole-punched stainless plate was used as the high voltage electrode in order to improve nano-particle collection efficiency. The collection efficiency as a function of the particle diameter was studied. As a result, the nano-particle collection efficiency on the ESP with the hole-punched high voltage electrode was significantly improved. In the case of certain number of hole, the nano-particle collection efficiency increases with increasing the punched hole diameter. In the case of the constant of aperture rate, the nano-particle collection efficiency increases with decreasing the punched hole diameter. This effect is probably due to increasing the electric field intensity near the hole edges of the hole punched electrode.

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In recent years, because of the rapid progress in wireless technology, microwave absorbers or noise suppressors have become necessary for a safe-electromagnetic-wave-level environment. To design microwave absorbers or noise suppressors, it is necessary to have knowledge of complex permittivity, ε_r^* and permeability, μ_r^*. In this report, we show the values of complex permeability, μ_r^* and permittivity, ε_r^* for a composite materials of magnetic (Iron, Fe, coated by Fe₃O₄) and dielectric (Titanium Oxide, TiO₂), by changing Fe / TiO₂ volume fraction ratio. As changing of these, we can change the values of complex permeability (μ_r^* = μ_r' - jμ_r") and complex permittivity (ε_r^* = ε_r' - jε_r"). And the results are applied in the design of a microwave absorber which makes reflection losses and the central frequency to do a purpose, for example, necessary conditions of ETC (5.8GHz) use in Japan.

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To understand the mechanism of surface processing using an atmospheric-pressure non-equilibrium microwave discharge plasma jet, we used optical emission spectroscopy to measure the vibrational and rotational temperatures of plasma. A microwave (2.45GHz) power supply was used to excite the plasma. The vibrational and rotational temperatures in the plasma were measured at approximately 0.18 eV and 0.22 eV. We also conducted plasma surface processing of polyethylene naphthalate (PEN) film to measure changes in the water contact angle before and after the PEN film was processed and as the rotational temperature of the plasma increased. Analysis of all the results from XPS, and surface free energy as calculated from the contact angle confirms that the improvement in hydrophilic properties of the PEN film surface using the microwave discharge plasma jet were effective, after comparing improvements in the hydrophilic properties of PEN film surface by plasma exposure. We conclude that the hydrophilicity of the polyethylene naphthalate film surface improves as the rotational temperature of the plasma increases.

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The authors proposed the novel evaporation supply method, flashing spray chemical vapor deposition (FS-CVD). In the experiment, tetrakisethylmethylamidohafnium (TEMAH) was used as the precursor and n-pentane was used as the low boiling point organic solvent. The critical consolute temperature of TEMAH and n-pentane mixed material solution was 276K. The vapor pressure of the mixed material solution was ten times higher than that of TEMAH by formation of two-phase region. HfO₂ film was deposited on Si wafer by using TEMAH and n-pentane with FS-CVD. As the result, the uniformity of HfO₂ film was +/-5% and film thickness was 133.6nm. The uniformity of HfO₂ film of refractive index was +/-5% and refractive index was 1.63. It is found that the precursor was evaporated by flash boiling and HfO₂ film was deposited by decomposition.

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