Central Research Laboratory, Hitachi, Ltd. Epitaxial films of silicon have been grown on sapphire substrates by the hydrogen reduction of SiCl4. The structure of silicon films and deposition rate were shown as a function of a mole fraction of SiCl4 in hydrogen and as a function of substrate temperature. The uniformity of orientation in the deposited silicon films-improved as they were made thicker. The linear relation observed be-tween the legarism of the deposition rate and the reciprocal of the substrate temperature yielded an apparent activation energy of about 20 Kcal/mol for growth. The epitaxial relationships between the deposited silicon and sapphire substrate have been established using electron diffraction and X-ray Laue back reflection techniques. It was found that, even on the (0001) and (1123) sapphire which were inclined at an angle of some ten degrees, (111) and (110) silicon, respectively, have been grown parallel. For growth on (1012) sapphire, (110) silicon was parallel to the interface.
Since movable tube flowmeters are based upon a measuring principle independent of Bernoulli's theorem, they enable us to measure flow rates regardless of viscosity losses. Both of the two types, of movable tube flowmeters, previously reported, however, need to determine two quantities, namely, “two pressure differences” or “a pressure difference and the external force acting on the tube”. For the new type flowmeter, here reported, two additional bellows are provided which enable us to cancel the terms involving pressure differences in the theoretical formula. It is, therefore, only necessary to determine one quantity and the measurement of flow rates is considerably simplified. The experiments showed good agreement with theory.
The measuring principle of a bend flowmeter based on Bernoulli's theorem is systematically developed in this paper. It is shown theoretically that the liquid head at any point of the tube is exclusively a function of the distance from the bend axis and the pressure taps may be in the form of slits along the inner and outer bend circles. The slit type tap is verified experimentally to be very advantageous from the point of view of uniformity of flowmetric characteristics. U bend tubes are adopted in view of the necessity of using a straight tube of considerable length. The experi-mental results show that the four laboratory-made U bend tubes with slit taps all show the same flowmetric characteristics, and flow rates can be obtained from measured values of liquid head differentials with a discharge coefficient of 1.
Maréchal method of aberration balancing is applied to the analysis of holographic imaging systems. We discuss, on the basis of Meier's formulas and seidel coefficients, how to find the best imaging system and how large the field of view should be. From this analysis, we found an optimum system for holographic microscopy. Although the lensless Fourier transform system allows us to use low resolving emulsion, it is found that the working distance should be im-practically small for high power imaging systems.
Several types of the corrosive action of CO, N2, O2 and Ar gases on a tungsten tip in presence of various electric field are studied with the field-ion microscope. There are no corrosions by O2 and N2 gases at high field conditions above 70 per cent of the field-evaporation voltage. However an adsorbed CO gas is diffused from shank to apex of the tip at the same field strength and give rise to violent field-evaporation. Below field-ionization voltages of gases, the gas molecules in the space can reach the crystal planes on the tip and lead to preferential heavy corrosion depending on the field strength on each crystal planes. A possible mechanism of corrosions of the tungsten tip by various gases in the field-ion microscope is discussed.