Research and production of semiconductor materials have required reliable analytical methods for ultra-trace impurities in them. Radioactivation analysis is of the widest use, and many impurities have been determined by neutron activation. We established processes of analyzing semiconductor silicon for halogens, and determined them in the samples of various origins. Ultratraces of carbon, nitrogen, and oxygen should be determined by charged particle activation analysis. We set up the analytical processes and analyzed semiconductor silicons of various origins for the three elements. Thus, their behaviours in course of the zone-refining and the singlecrystal formation were examined and made clear, and such quantities as solubility of carbon in solid silicon at its melting point and equilibrium distribution coefficient of carbon in silicon were determined. Also, pyrolytic graphites were analyzed for trace nitrogen, and its behaviour was persuited.
The behaviour of mono-and polycrystalline silicon steel sheets under high velocity deformation was studied. As the strain rate increased, in single crystal and coarse-grained specimens total elongation decreased and the fracture mode became brittle, while in fine-grained specimen total elongation increased and Lüders bands grew apparent. Several patterns characteristic of mechanical twins were observed at the grain boundaries in coarse-grained specimens. They were clearly affected by a relation involving crystallographic orientation between two adjacent grains. The value of cosα · cosβ, where α is the angle of twin directions and β is the angle of twin planes between two grains, proved important for discriminating these patterns. After recrystallization, no polygonization were observed in the specimens which had been deformed at high strain rate.
Temperature dependence of the stress-birefringence effects in crosslinked polyesters was investigated using the Sénarmont's compensator method with an automatic recording apparatus. It was obtained that: (1) The photoelastic effect arose predominantly from the instantaneous orientation of the backbone chain. (2) The retarded-photoelastic effect in crosslinked polyesters was a summation of two contributions-a positive contribution from phenyl groups in the backbone chain oriented parallel to the backbone plane, and a negative contribution from phenyl groups of the side chain oriented perpendicular to the backbone chain. (3) The phenyl group of the side chain became gradually oriented perpendicular to the backbone chain with increasing temperature; the retarded photoelastic coefficient, therefore, decreased with temperature, and a reversal in sign was observed. (4) The R. P. E. transition temperature was interpreted as the temperature at which a summation of a positive and a negative contributions became zero.
The photoelastic effect in γ-irradiated crosslinked polyesters was investigated at various temperatures using the Sénarmont's compensator method with an automatic recording apparatus. The results obtained are following. (1) The change in the photoelastic coefficient is similar to the change in the compliance of irradiated crosslinked polyesters. (2) Little change of the photoelastic coefficient and the compliance was obtaind by irradiation, can be considered that the photoelastic effect is predominantly determined by an instantaneous orientation of the backbone chain. (3) In addition, it is also suggested that new photoelastic materials might be provided by irradiating the polymeric materials with γ-rays.
The retarded-photoelastic effect in γ-irradiated crosslinked polyesters was investigated at characteristic temperatures by the apparatus used in our previous works. The results obtained are following. (1) The R. P. E. transition temperature was shifted to the higher temperature with the dosage of γ-rays, and in some cases (in the vicinity of the R. P. E. transition temperature), a reversal in sign of the retarded-photoelastic coefficient was observed from positive to negative. (2) Above the glass transition temperature, the motion of the phenyl group of the side chain is not almost hindered sterically, even if the samples are irradiated by the γ-rays. In the temperature range, the retarded-photoelastic coefficient is, therefore, hardly affected by radiation dose. (3) The retarded-photoelastic effect in irradiated crosslinked polyesters can be explained as the summation of two contributions… a positive contribution from phenyl groups in the backbone chain oriented parallel to the backbone plane, and a negative contribution from phenyl groups of the side chain oriented perpendicular to the backbone chain.
An apparatus was constructed to measure the velocity and attenuation of longitudinal ultrasonic waves through textile fibers by an ultrasonic pulse technique. The present apparatus enables the measurement of acoustical properties of short fibers, e. g. several centimeters long by the usage of ultrasonic waves of 1 MHz. Special considerations are paid for the setting of ultrasonic oscillator in this apparatus. The specimen can be examined either in air, vacuum, or nitrogen atmosphere and at various relative humidities. The temperature range of measurements is between room temperature and 150°C. Accurate measurements can be obtained even for short cotton fibers of length of three centimeters. The errors in velocity and attenuation measurements for cotton fibers are 1% and 5% respectively.
Glass lasers usually show no definite polarization in their output light. But those using a Porro prism as a reflector are expected to have transverse modes polarized only in a direction either parallel or perpendicular to the edge of the prism. This is because the phase shifts for the two components at total internal reflection are not equal and an obliquely polarized mode can not regenerate itself in the cavity. Experimentally, these two polarization components were observed to oscillate alternatively, which exhibits the validity of the above discussion and indicates a coupling between them which may be due to spatial hole burning.
An optical interaction in GaAs diode lasers was observed in the “tee” configuration between an emitter diode and an irradiated one. By varing the interval of time between the injection pulse currents of the two diodes, we observed an enhancement of laser light from the irradiated one in addition to a quenching effect reported before.