Zur Ganggeschwindigkeit von Uhren auf der rotierenden Erde

On the Rates of Advance of Clocks on the Rotating Earth In 1905 ALBERT EINSTEIN came from his Special Theory of Relativity to the conclusion that a “balance clock” located at the earth's equator is somewhat slowed down compared with a clock resting at one of the earth's poles P (see Fig. 2 below). But interestingly, this retardation of time is fully compensated by an opposing gravitational effect which (according to the General Theory of Relativity, discovered later by EINSTEIN, 1908 - 1915) causes all (atomic) clocks even at any point A on earth's surface at normal sea-level at arbitrary latitudes φ to advance at the same rate as the clock at the pole: The kinematic time-dilatation of a clock A moving with the velocity v of the earth's daily revolution around its axis turns out to be precisely equal in magnitude to the acceleration of the advance of the same clock A with respect to the clock at P due to the gravitational potential-difference between A and P, resulting from the ellipsoidal figure of the rotating earth. These two variations in the clock-rates, amounting relatively to 1/2 (v/c)², where c denotes the velocity of light in vacuum, exactly cancel each other. Furthermore the so called clock-paradox and the Hafele-Keating-Experiment are rediscussed in a somewhat different way than usual.     

Die einwirkung der struktur auf die kristallisationskinetik des glasigen selens

By means of a calorimetric method the rate of crystallization of vitreous selenium samples remelted at various temperatures t_U (225–3502C) was studied at a temperature of 90.0°C. To describe the kinetics the Avrami equation was used. The samples remelted at t_U < 260°C crystallized in one stage, A. For the samples remelted at t_U ? 260°C two stages, A and B, were observed. The rate constants k_Kr = z(L · c_Kr)$\text{1}\text{2}$ and the coefficients z were calculated from the Avrami equation. For the samples remelted at t_U = 225, 250 and 330°C, the activation energy e_kr was determined.The values of z, k_Kr and z · E_Kr were found to decrease as the temperature t_U increased. The kinetics of crystallization probably depend upon the structure of vitreous selenium (i.e. on the number of crystalline regions and on content of the small rings), which in turn is dependent on the temperature _U. This supposition was confirmed mathematically.     

Die Sauerstoffspannungsreihe und ihre anwendung auf die technologie von halbleitern

For the dissociation of oxides, also referred to as “half reactions” the chemical potential will be defined. In analogy to the electrochemical voltage series these chemical potentials may be arranged in an “oxygen pressure series” which immediately enables one to determine the change in free energy in case of reactions with oxygen transfer. Thus the thermodynamic tendency for these reactions to proceed will be fixed in a quantitative manner.The dependence on temperature and pressure of the chemical potentials will be mentioned. Some applications as for example the behaviour of quartz or carbonized quartz in the synthesis of semiconductors will be discussed.     

Die Einwirkung der Te- und s-beimischungen auf die kristallisationskinetik des glasigen selens

The influence of tellurium (up to 6 at %) and sulphur (up to 2 at %) admixtures on the rate and on the activation energy E_Kr of vitreous selenium crystallization was investigated by means of calorimetric method. The results satisfy the Avrami's aquation x = 1 ?exp(?L · c_Kr · τ^z). The exponent z and the product z·E_Kr, are increased due to addition of tellurium admixtures, while the value L · c_Kr is decreased. The admixtures of sulphur decrease the exponent z, but have not any influence on the values L · c_Kr and z · E_Kr.Probably the tellurium admixtures increase the rate of the crystallite growth and the number of the crystallization centres, what accelerates the process. But at the same time, formation of the stable nucleus is prolonged. Sulphur admixtures do not change the contents of the small rings and of the hexagonal regions in vitreous selenium. They produce deffects in the chain structure, what retards the crystallization.