Water-in-oil emulsions of various volume percentages (0_??_85%) are made by dispersing distilled water in three kinds of oil of nearly equal dielectric constants (2.1) using ester of oleic acid and polyethlene glycol (molecular weight: 200) as emulsifier. The dielectric constant is measured by Ichijo's double resonant circuit, the temperature and the frequency being kept fixed at 20°C and 2 megacycles respectively. The results are checked with three known formulas. Bruggeman's formula is found to agree best within the experimental accuracy even up to the volume percentage of 85% surpassing 74% which is the limiting value of dispersion of spherical particles.
In the previous paper, the author summarized the process of water suction for the specimens of cryptomeria under almost the same definite conditions. In this paper, a simple theoretical expression, which has a few complementary terms, is introduced assuming that the rise of water in tracheids for a short time after soaking is caused only by its surface tension, neglecting its vapour-diffusion. It is suggested that the penetration-resistance of water and its meniscus through the pits can be approximately represented by an effective diameter. Application of this expression to measurments will be shown in the next neport.
Glass beads of equal sizes are sintered in a small cylindrical vessel under compressive load. The relations among the diameter of bead, load, sintering time and the lowest sintering temperature are determined by the method described in the former report (1). The dia-meters of beads tested are 1.30, 0.85 and 0.45mm. The ratio of the diameter of the adhered area between two beads to the diameter of the bead is found to take a certain value independent of the dimention of the bead under the same load, but it becomes larger with the load. If the degree of sintering could be determined by this ratio, it would be that the smaller the beads, the lower the sintering temperature under the same sintering time and load. The formura, which had been obtained theoretically by the author expressing the rate of growth of the adhered area between two beads is in agreement with the experimental results regardless of the dimention of the bead from which it can be said that viscous flow is the main part of the mechanism of bonding in case of the hot-press sintering of glass beads.
Microstructures of fractured surfaces of metals are observed by electron microscope. Fractured surfaces of polycrystalline ductile metals accompanied with considerable plastic deformation, consist of domains of the sizes comparable to those of crystal grains. In the cases of tempered steel and age-hardened duralumin the sizes of these domains are very small as compared with those of the normalized metals. On the stereo electron micrographs of the fractured surfaces it is observed that the interiors of these domains are dented. Fracture of ductile polycrystalline metals is regarded to proceed by the following steps: (1) As the plastic deformation progresses, large concentration of stress is produced in the grain boundaries or in the neighbourhood of precipitates. (2) Therefore at these positions microcracks are induced. (3) But around the crack, it is yet ductile enough to continue plastic deformation. Therefore the stress concentration at the crack apexes is relieved and cavities are formed. (4) This plastic flow continues until the rupture and the fractured surface appears with dented domains. Fractured surfaces of brittle metals also show the domain structures of the sizes comparable to those of the crystal grains. In the interior of these domains, glass like fracture is observed
Based upon Boltzmann's equations, general equations applicable to any phenomena related to beam electrons, gas molecules, and ions or electrons produced by collision are derived. The restrictions imposed are that the acceleration voltage of the electron beams are high enough compared with the ionization potential of the gas and the impressed electrical and magnetic field strengths are not so high as to ionize the gas molecules. In the latter half, these general equations are applied to the “Gas focussing”. In the first place, longitudinal flows of ions are calculated with the result that about one volt of dip in the axial potential distributions is sufficient to trap the ion. Then, the radial flows of ions are calculated, wherein the information about the probability η of recombinations of ions at the tube wall is required in deriving quantitative results. Relations between pressure, neutrality of beam, beam current and V are calculated and illustrated. It is concluded that the radial flow of ions play an important part in the trapped conditions when axial flow is interrupted.
The ultrasonic absorption for binary liquid systems, water-Triethylamin and water-Methylethylketon which have the lower critical solution temperature, is measured by the pulse technique at the frequeucies 0.98, 1.98, 3.00MC. Similar to the solution with upper critical temperature, the contribution of clusters to remarkable absorption is the greatest at the concentration for which the solubility curve shows minimum and becomes smaller as the temperature tends away from the critical point, and the relaxation frequencies seem to be as low as those of the solution with upper critical temperature.
With a usual bulb glass, an experiment has been carried out on the approach of specific volume to an equilibrium value for several samples which were pre-treated under various conditions, i. e. by quenching, annealing and stabilization. An electric self-controlled furnace is used for the heat treatment and the density at 20°C is measured by means of the sink method by using an aqueous solution of potassium iodide and mercuric red. After treated for a sufficient time at a constant temperature in the transformation range, the density of the sample approaches to an equilibrium value from which and characteristic orientations of structural units seem to exist at respective temperatures within the range. From the curves of dV/dt vs. V, where V and t mean specific volume and time respectively, it is found that: (i) The shape of relaxation curve is not always determined from the direction of approach towards the equilibrium state. (ii) At the same holding temperature, the rate, dV/dt, is not the same even for the samples of the same specific volume if they are differently pre-treated. The non-equilibrium state during stabilizing process of glass is presumed to depend on the thermal history of the sample. (iii) Samples, which are incompletely annealed and are kept at a constant temperature different from that of the annealing, undergo a rapid dilatation followed by a gradual contraction. This volume change is thought to have been caused by the combined effect of varied binding conditions among the structural units and the difference in structural orien-tations between the initial and final states. As for the structural unit that contributes to the volume relaxation, a chain of solid clusters of Si-O4 groups, for example, is reasonably conceived.