Deviation of punch load center from punch center, lateral force exerted on the punch head and eccentricity between punch and die are measured through the process. In extruding a blank of slant end, punch is remarkably bent toward the low end side by the lateral force in the initial stage of extrusion. The punch tends to recover elastically in the subsequent stage, and the eccentricity between punch and die decreases as the process proceeds. The recovery is, however, retarded more or less by the resistance of the deforming metal around the punch. In extruding a blank of which lubricant film is removed from a half of the end surface, both the deviation of punch load center from the punch center and the lateral force induced by the non-axisymmetric flow bend the punch toward the dry end side. The eccentricity between punch and die increases with increase in the punch penetration.
In order to grasp the possibility of evaluating shear properties for solidified lubricants under high pressure, plastic deformations of metal micro-spheres (about 0.07mm) in solidified lubricants were evaluated by employing a diamond-anvil pressure cell (DAC). Large deformations (2–5 times larger than the original sphere dimensions) were observed for CVT oil and ester oil up to 6 GPa at 23–25°C. Deformation starting pressure agreed with the solidified pressure. These deformations were caused by the non-hydrostatic pressure in the solidified lubricants. Shear stresses of the solidified lubricants were tentatively and roughly estimated from the plastic deformations of the spheres based on some assumptions. They almost agreed with the mean shear stress (traction force / hertzian contact area) from traction test.
The hetero p-n junctions of LBMO/ZnO were fabricated by ion beam sputtering. The sample shows clear temperature-dependent rectifying current ( I )-voltage ( V ) characteristics, and junction resistance vs temperature curve is reflected by the CMR nature based on DEC model. The sample shows two-step switching, then the I - V is composed of very-low-resistance (VLR), low-resistance (LR) and high-resistance (HR) regions. The whole I - V behavior is changed by measurement running current. The switching is caused by the spot current, and the original VLR is restored when the current is reduced. The mechanism of switching is proposed in terms of the percolation paths composed of metallic FM-grains. Photo illumination effect on the I - V was investigated. The currents are increased in VLR and HR regions by the illumination. Two origins are possible, electronic process due to hole injection, and phase process. The percolation path might be reinforced by the light.
Based on an indication in the previous research that there is an ocean bacterium which can reduce iron red rust to magnetite extracellularly, it is attempted to develop a new recycling process employing such kind of bacteria. Two methods for producing very fine magnetite powder from red rust are presented by making up an artificial environment and shown to be successful. Bacteria participating in magnetite production are examined in detail, and are found to be microaerobic ammonia-oxidizing bacteria (coccus and bacillus), regarded as new types different from the GS-15 bacterium reported earlier. Their role is clarified and a mechanism of magnetite formation is presented.
Characteristics of the free surface profile of aluminum sheets under uniaxial tension are examined by employing fractal analysis. As a fractal analysis method applicable to a self-affine surface, a zeroset method for generating intersections of the surface profile in a base plane is presented. It is found that the fractal dimension of a surface resulting from plastic deformation tends to be constant (2.35), and each asperity has a uniform fractal structure. Other fractal analysis methods, the box-counting method, power spectrum method and zeroset method were applied to surface profile curves obtained using a stylus profilometer, and the characteristics of various fractal dimensions are discussed. From these results, the geometry of surface profiles under uniaxial tension is clarified.
High-pressure viscosity was measured for lubricant oils including a traction CVT oil up to 2.7 GPa at elevated temperature up to 200℃ employing a falling sphere method in a diamond-anvil pressure cell (DAC). The obtained relations between logarithmic viscosity and pressure at all temperature (40℃〜200℃) showed the non-linearity with some data scattering. Therefore, viscosity-pressure coefficient α was not constant and decreased with pressure for lubricant oils and increased for a traction CVT oil. α was also dependent on temperature. These dependence should be considered for EHL oil film thickness analyses concerning fatigue life of machine elements. A pressure temperature phase diagram of liquid-solid transition was plotted from the obtained high pressure viscosity, which predicts traction feature.
