The merits of U. H. V. E. M. (Ultra High Voltage Electron Microscope) and demands from metallurgical science are surveyed. The history of constructions of U. H. V. E. M. in Japan is reviewed briefly. It is mentioned that the utility of U. H. V. E. M. exceeds the predicted one. It is also applied to biological specimen and assured to be very useful in steroscopic observation of thick specimen. Japanese research groups equipped with U. H. V. E. M. are introduced. The outline of 3 MeV U. H. V. E. M. which is under construction in Japan is sketched. Finally, the problems of the future Mega-volts E. M., accelerating system, lens, observation and recording of E. M. image, are discussed.
As the lower pressure of hitherto used crifice flowmeter, with vena contracta tap or corner tap, pressure at the position of the vena contracta is taken approximately. But the phenomenon of the vena contracta is so complicated that the interchangeability of orifice flowmeter can hardly be obtained without the strict standardization of the orifice plate. The new orifice flowmeter here reported has the taps within the orifice plate itself, and the pressure at the orifice plate itself is taken instead of the pressure at the vena contracta. The profiles of these plates are shown in Fig. 2. The upstream side of the orifice hole is rounded with five kinds of radius, i, e., r=0, 0.5, 1.0, 1.5 and 2.0 mm. The experimental results, in the region of Reynolds number 3×103_??_3×104, show that the orifice with 1.5 mm radius has a better interchangeability than other orifice plates, and that the flowmeter enables us to measure the flow rate regardless of vena contracta as it is expected.
As an experimental device for the study of digital optical information processing by a computer, a half-tone plotter has been used. This device can display a half-tone drawing on a conventional cathode ray tube, and is useful for giving an optical information by a computer processing. On the other hand, the fast Fourier transform algorism has greatly reduced the computing time of Fourier transforms. This is especially important for two-dimensional Fourier transforms, which often appear in the optical information processing. In this paper, the digitized Fraunhofer holograms are synthesized with a computer and a haf-tone plotter. The comlex amplitude of Fraunhofer diffraction (hologram) of an image can be synthesized by a computer processing with a technique similar to the binary hologram, and it is displayed as a continuous tone digitized hologram on a cathode ray tube with the half-tone plotter. These holograms are photographically reduced and the images are reconstructed optically. A certain consideration on F. F. T. is also developed.
The temperature rise of an avalanching Si p-n junction diode has been calculated numerically by considering the temperature dependent thermal conductivity of silicon and assuming a one-dimensional structure of the diode. The effect of the two heat sink structure of the diode is calculated. The numerical analysis is compared with the experimental results obtained from the voltage-current characteristics in the avalanching region.
New laser oscillation in ionized xenon at 5591±2Å has been obtained by the use of pulse excitation supplied by capacitive dis-charge at a low pressure (0.02_??_0.04 Torr). This oscillation is dominant in a rather longer current pulse duration, which seems to sug-gest the possibility of cw oscillation, whereas the seven already known XeIII and XeII laser lines (4954, 5008, 5159, 5260 or 5262, 5353, 5395 and 5971 Å) observed by the same appar-atus oscillate exclusively under the excitation of the shorter pulse and higher peak current. The new line was tentatively assigned to XeII 7 s'2D3/2 -6 P'2D3/2 transition, 5591.6Å. It is also shown that the output of pulsed ion laser is much influenced by not only the cur-rent density but the current pulse duration.