Size distribution of photo-pulses in a DC positive corona discharge by wire-to-plate electrodes is recorded as a function of the applied voltage. Measurements are made in regions of intermittent corona and steady burst pulse corona, and the effect of external radiation on the corona characteristics is examined. The characteristic of intermittent burst pulse corona is observed to change sensitively into what resembles the characteristic of steady corona when the corona gap is irradiated with β-rays or ultra-violet rays or even with α-rays that come from a P0 source to be counted by the corona instrument used as a spark counter.
Based upon the transfer function, we can obtain a well balanced radiographic system by measurements of spatial frequency characteristics between consecutive components comprising an X-ray tube, object, intensifying screen and film. From spatial frequency spectrum and phase obtained by Fourier analysis of X-ray tube focal intensity distribution along the beam through the system, the existence of spurious resolution is confirmed theoretically. And from the focal intensity distributions found by varying independently the tube voltage and the tube current, the variation of focal spatial frequency distribution is clarified, which will contribute to obtaining accurate information on the filmed image. A new method of measuring the sine wave response by the use of the principle of stroboscope is suggested, and some results of experiment made by this method are given.
The relation between the internal reflectivity of output end face of a laser rod and the energy output under usual excitation is investigated. By analytical calculations, the following are deduced. (1) For a given pumping energy, there is an optimum value of end face reflectivity to maximize the energy output. (2) This optimum value decreases as the pumping energy increases. (3) The maximum value of output energy is proportional to the square of logarithm of this optimum value of reflectivity. (4) As is known, the energy output varies linearly with the pumping energy for a given value of reflectivity and depends largely upon the losses in the rod. Changing of reflectivity of the end face is equivalent to varying of the degree of coupling with the rod, for which two methods are tried, one is to increase gradually the number of small holes made by removing the dielectric multilayer that covers the end face to make it a mirror, the other is to vacuum-evaporate a silver film onto the end face and to vary its thickness. The value of energy output obtained by measurement is in reasonable agreement with the value obtained by calculation.
An apparatus for cutting crystals through any desired crystallographic plane has been devised. The main part of the apparatus consists of a rotating-wheel cutter, a crystal-holding gonimneter, and an optical system, all of which are mounted on a single base. Additonal attachments for the circulation of cutting oil, automatic cutting feed, and automatic stop are provided. With this apparatus, any desired crystal plane to be cut can be determined rapidly and accurately by the light figure method and the crystal can at once be cut by the rotating-wheel cutter. The accuracy of cutting through a specified crystal plane is within 0.5°, the time required for cutting varying widely with the kind of crystal to be cut. Actual examples of cutting some crystals are given. This apparatus can also be used for accurate and rapid orientation determination of single crystals and individual grains in polycrystalline rod or plate by the light figure method. Detailed procedures for the orientation work are illustrated.
The snowslide is usually studied by treating the laid snow as being plastic. But in Fukui district, as it seems elastic rather than plastic that is characteristic of colder districts, a simple elastic model of snowslide is conceived with the following conclusions. (1) The magnitude of a moving mass of snow in the form of a snowball, the impact of which against the laid snow is necessary to originate the snowslide, can be estimated. (2) The concerned snow-mass, when it is a broken fragment of a cornice, becomes also computable. With the measured values of mechanical constants of laid snow, the magnitudes of the concerned snow-mass in the above two cases are calculated and are found to be of the same order. This confirms that the snowslide in Fukui district can be explained by the elastic nature of laid snow.