An analytical method for exactly drawing current and equipotential lines in a conditional rectangular compound region consisting two anisotropic media is presented. In the region, the internal boundary of two media is on the diagonal line of the rectangle and the electrodes are attached to opposite sides.
In the method of this paper, first, the rectangular region is transformed to a mirror anti symmetrical region with a different resistivity tensor from that in the original region, under some limitations. By the transformation, however, the field continuity on the boundary is conserved. In the transformed region, the angles of incidence and refraction for the current and equipotential lines on the boundary can be determined, respectively. Next, another compound region with the known electric field and with the same boundary conditions as those in the transformed region is considered. Thus, the current and equipotential lines in the rectangular region can be easily obtained by mapping those in the region finally considered because each region in the analytical procedure gives us the same solution for the electric current field to be solved.

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The behavior of bubbles in liquid nitrogen under non-uniform fields is studied experimentally and discussed on the basis of an analytical study on electrical forces acting on bubbles by the authors. A plane-to-cylinder with/without two dimensionaly triangular fins is used as the tested electrode and the orientation of the fin on the cylinder is chosen to be circular or longitudinal. The results are as follows: the macroscopic non-uniform field roduced by the plane-to-smooth cylinder drives bubbles away to lower field region but bubble-aggregation appears when the electrical gradient force balances with the buoyancy; the microscopic non-uniform field by the fins locks bubbles in the groove between the fins and the bubbles move to a region of lower macroscopic field and are released into the surrounding liquid there. The bubble observation with different fins, circular fins and longitudinal fins on the cylinder, shows that the cylinder with the circular fins is optimum to guide the bubbles along the groove to a region of lower microscopic fields and to release them there. It is argued from the present study that the groove directed toward the gradient of the macroscopic non-uniform field on the electrode is effective for preventing both the vapor lock in the gap and the reduction in breakdown voltage and promoting the heat transfer from the electrode to liquid.

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In this study, the electron swarm parameters defined by the arrival-time distributions of electrons in N₂ are calculated by a Boltzmann equation method, and the newly-introduced evolution equation which includes these parameters is solved to derive the theoretical arrival-time distributions. The new evolution equation is deduced by the interchange of space and time in the conventional continuity equation. The calculated results of the parameters and of the arrival-time distributions are compared with those by a conventional time-of-flight (TOF) experiment using the double-shutter drift tube. It is shown that the theory introduced in this study directly corresponds to the conventional TOF experiments.

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The electrical breakdown phenomena in benzene and in cyclohexane for positve polarity with point-to-plane electrode configuration have been studied by using an image converter camera in conjunction with a photo optical current measuring system. The photographic records show the propagation of positive streamers with average velocities ranging from sonic to supersonic (1.3to> 10km/s) s for about 4mm gap spacing and the applied voltage range 25-50kV. The fast secondary streamer different from the slow primary one is occasionally observed under a higher applied voltage. The streamer velocity in benzene under a lower applied voltage is equl to that of the accompanying shock wave. Time to breakdown for gap spacing <4mm was precisely measured from prebreakdown current. The average velocity of streamer propagation is estimated from the linear relation between the time lag and gap spacing. A common propagation velocity of 1.3km/s is obtained from the relations for benzene and cyclohexane. A breakdown propagation model involving a field ionization process is presented.

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InSb this films were prepared by conventional vacuum evaporation with the suitable temperature program for source and substrate. The deposited films had InSb-In structure due to the loss of antimony during evaporation process. The films showed large magnetoresistance by the segregated indium inclusions. The lower electron mobility films with higher density of indium inclusion had higher magnetoresistance than that of stoichiometric films with higher mobility. The difference of substrates for crystal growth and segregation of indium were also investigated. Though the electron mobility of the films deposited on glass substrates was much lower than that of the films on mica substrates, the films deposited on glass showed compatible magnetoresistance to that of the films on mica.

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New sintering aids for the production of the high performance Nd-Fe-B permanent magnets were found. Powder of Rare-Earth Cobalt Boron intermetallic compound was mixed with that of Nd₂Fe₁₄B₁. With the suitable proportion of blending, energy product for the magnet was achieved 45 MGOe and over, which is the highest point in mass production base. It was because the powder of Rare-Earth Cobalt Boron alloy composed of Co-based intermetallic compounds such as R₁Co₂, R₁Co₃, R₁Co₄B₁ is so stable that Rare-Earth elements of the alloy were prevented from oxidation, which is inevitable in the case of ordinary production process.

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