In recent years there has been remarkable progress in our understanding of the properties of solid surfaces. Several factors which have contributed to recent developments in surface science are attributed to the advances of ultrahigh vacuum technology, modern experimental techniques, and handling of metals in very high purity. The investigations of gas-solid interac-tions, gained by various modern techniques, are reviewed on such topics as the adsorption states and binding energies of gases, surface reaction, and structure of adsorbed sarface layer on atomically clean metal surfaces.
An absolute measurement of the acceleration due to gravity has been carried out at the gravity station of the NRLM at Kakioka, Ibaraki prefecture. The measurement is based on the free-fall motion of a graduated linear scale of 1 meter in length with divisions lined every 1 cm. A value of 9.799648 m/s2 with a 95% confidence limit within an error of 0.7ppm was obtained. This value, which is reduced to the first floor of the station, is 15.3 mGal smaller than the value given by the Potsdam system. From an analysis of the data scattered about the mean value, it was found that the error dispersion in some experiments was affected by microscoseisms. The 95% confidence limit of the error at single experiment is estimated to be about 1 ppm by the method of least squares.
Output power properties of an HCN laser with gas mixtures of CH4+N2 and CH4+NH3 were measured as functions of flow rate, mixing ratio, discharge current and size of coupling aperture in both pulsed and CW operations. From these results the mechanism of excitation and relaxation, oscillation modes, and the saturation of output power for the discharge current are discussed. The obtained maximum power at 337 jtm oscillation was 2 W for pulsed operation and 80 mW for CW operation, respectively.
Spherical drilling and staining was studied and found to be one of the simplest methods for measuring the thickness of Si epitaxial layers, especially when their thickness was less than one micron. The minimum thickness which could be measured by this method was about 1000A with an error of less than 80A (8%). The results obtained by this method were compared with those by other methods i. e., beveling and staining, weight difference, and infrared reflection. This method was also applied successfully to the thickness measurement of dielectric or thin metal layers on Si substrate,