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An electrostatic sheet stapler (ESS) that can paste a sheet material on a target by electrostatic force has been developed as an adherence and removal method for future sheet devices. The stapler was composed of two couples of needle to grid electrodes as positive and negative corona chargers with an insulator support dividing the two corona chargers. The proposed sheet material has two adherence areas where the surface can be charged up and a functional area where a thin and flexible functional device is placed; typically devices from printable electronics technology. The sheet device is adhered onto the target electrostatically; therefore, the force can be easily controlled, which provides a possible mechanization process for the adherence and removal of sheet devices without an adhesive material. Here we describe the theoretical concept of the ESS and measure the withstanding weight using a test model ESS. The time variation and distribution of the surface potential on the charged sheet and the adherence force are also reported.

For comparative assessment of tokamak and helical reactors, two base case reactor designs with 1 GW electric power output are introduced; high-field high-beta compact tokamak reactor TR-1 (major radius R = 5.2 m, magnetic field B = 7.1 T) and high-beta helical system HR-1 (R = 12.1 m, B = 4.6 T). Operational boundaries of both reactors are compared by the zero-dimensional energy balance model, which clarifies the difference between the higher temperature operational regime of TR-1 and the lower temperature regime of HR-1. These operational scenarios are reconfirmed by the toroidal transport analysis linkage (TOTAL) code coupling with two-dimensional equilibrium in the TOTAL-T tokamak code and three-dimensional equilibrium in the TOTAL-H helical code. The beta effect on confinement degradation and the impurity radiation effect on energy balance are found to make the ignition difficult in both systems.

The charging characteristics of polymer particles were investigated in order to develop an electrostatic separator for plastic-plastic mixtures which are to be recycled. The charging section of the proposed separator utilizes a vibrating feeder equipped with a charging plate. Plastic particles are charged by triboelectric charging while moving on the plastic plate. In order to increase the amount of a charge acquired by the plastic particles as well as to avoid an accumulation of a charge at the surface of the plastic plate, a plastic layer with a number of holes was formed by melting fine plastic powder over an aluminum plate. The charging characteristics of several kinds of plastic particles were investigated and the results show that the plastic-laminated vibrating plate is effective in charging plastic particles.

Transmission lines passing through a mountainous region often are struck by winter lightning. As a result, numerous double-circuit faults occur. Space charge might be responsible for this phenomena. Several investigations on flashover characteristics have been performed focusing on reduction of flashover voltage due to ionic space charge formed by corona discharge. In this paper, flashover characteristics of an air gap within a charged droplet cloud ejected from an airless nozzle using an induction charging method are discussed. The droplets are charged in the range -200 to 200 μC/kg, forming the space-charge density of approximately 13 μC/m3. The flashover voltage and the time lag to flashover were measured when 1.2 × 50 μs lightning impulse voltage applied to a rod-sphere gap is placed within the charged cloud. Flashover voltage for a positive rod increased markedly within a positive charged cloud by increasing the charge-to-mass ratio. The increase of flashover voltage was up to 80 percent in comparison with uncharged droplets. Flashover voltage for the negative rod decreased about 20 percent in the cloud of either polarity. The results show that the presence of charged droplets in the air gaps affects the discharge process significantly.

We studied the radiation hardness of the ZnO/ZnMgO heterostructure field-effect transistors (HFETs) by irradiating 200 MeV proton beam for fluences up to 3.6 × 1014 p/cm2. The change of the characteristics was monitored and compared with those of GaAs HEMTs. The saturation drain current for the ZnO/ZnMgO HFETs decreased by 10% while that of GaAs HEMTs decreased by 50% at proton beam fluence of 3.6 × 1014 p/cm2. The results demonstrate the superior radiation hardness of the ZnO/ZnMgO HFETs. The fact that little resistance change was observed for the as-grown ZnO/ZnMgO heterostructure implies the reduced drain current observed for HFETs might be caused by degradation of gate dielectric.

Investigation on removal method of SF/sub 6/ was carried out by using nonthermal plasma generated by pulsed power. We investigated the dependence of the discharge power and the polarity of applied pulsed voltage to the reactor on the removal rate of SF/sub 6/. The discharge power is varied with discharge repetition rate or charging voltage of the capacitor. As the discharge power increases, the removal rate of SF/sub 6/ is increases. The high repetition rate of pulse is more effective for removal of SF/sub 6/ than the big value of charging voltage. When the same discharge energy is supplied to the sample gas by changing the residence time or repetition rate, the removal rate is high in short residence time and high repetition rate. The removal rate of SF/sub 6/ for negative pulses is higher than that for positive ones. Consequently, the nonthermal plasma generated by pulsed power is effective to remove dilute SF/sub 6/ gas completely.

The behavior of water droplets placed on the surface of a hydrophobic polymer plate under a DC field was investigated experimentally. In order to confirm the effect of hydrophobicity on the movement of the water droplet, three kinds of hydrophobic insulating materials-PTFE, silicone rubber (SR) and ethylene propylene rubber (EPDM)-were used. Water droplets were placed on the insulating plate in contact with the aluminum foil electrode or placed between the thin foil electrodes. A single droplet placed in contact with the electrode on the SR or EPDM plate was elongated and a water filament extended along the surface by the electrostatic force, while that on the PTFE plate left the electrode. The water droplet placed on the border of electrode at the PTFE plate was deformed and formed a semi-cone at a triple junction. The apparent contact angle varied with time for a constant applied voltage and some amounts of charge were emitted by micro discharge or by ejection of small droplets. The behavior of the droplets under DC field strongly depends on not only the hydrophobicity but also the surface property of an insulating plate.

Since the elongated particles have experimentally shown better ER effect than spherical ones, chain formation mechanism of suspensions was investigated by using a large scale model. In series of the experiment with this large scale model, interesting and peculiar particle motions were observed. Experimental set up consists of parallel electrodes immersed in Silicone fluid whose conductivity was changed by adding butylalcohol. The motion of propylene rod with a diameter of 0.7 mm and 6 mm long was examined by using video camera and also high-speed camera. At very low conductivity, there is no motion of the rod. When the conductivity is increased, there is many different kind of motion observed. Rotational motion was most frequently observed at a certain range of conductivity. Further increase of applied field, there is a circular motion of the rod. The rotational speed increases with the applied field. However, when the circular motion starts, the rotational speed decreases. The highest rotational speed observed was 11 rps.

Summary form only given. Sulphur hexafluoride (SF/sub 6/) is useful as an insulator of a circuit breaker and as an etcher of semiconductors. Since SF/sub 6/ is one of greenhouse gases, emission of SF/sub 6/ must be limited and reduced. Investigation on removal method of SF/sub 6/ was carried out by using a pulsed corona reactor. An experimental setup is presented. The electrode of the corona reactor is arranged in a co-axial wire-cylinder configuration. The cylindrical tube is used as a cathode electrode and the wire anode electrode is aligned with the center axis of the cylindrical cathode. The concentration of SF/sub 6/ is measured with an absorption spectrometry. The corona reactor and a cell for measurement of SF/sub 6/ absorption in a sample gas are set in a closed gas loop equipped with two buffer chambers. The sample gas flows constantly in closed gas loop. The buffer chambers play a role to fix the concentration of SF/sub 6/ at an inlet of the corona. reactor during one measurement. The sample gas consists of SF/sub 6/ and helium. The pressure of sample gas is 1 atm. The pulsed voltage circuit is a type of capacitor charge transfer.

In the future fusion reactor, the plasma density peaking is important for the increase in the fusion power gain. The density control and the internal transport barrier (ITB) formation due to the pellet injection have been simulated in tokamak and helical reactors using the toroidal transport linkage code TOTAL. Firstly, the pellet injection simulation is carried out including the neutral gas shielding model and the mass relocation model in the TOTAL code, and the effectiveness of the high field side (HFS) pellet injection is clarified. Secondly, the ITB simulation with the pellet injection is carried out with the confinement improvement model based on the E×B shear effects, and it is found that the deep pellet penetration is helpful for the ITB formation as well as the plasma core fuelling in the reversed shear tokamak reactor, but the deep pellet penetration is not effective in the helical reactor.