Climatologies of tides at mid-latitudes in the lower thermosphere

Summary Time variations of the semi-diurnal and diurnal tides observed at Budrio (45°N, 12°E) in the wind structure of the lower thermosphere ((80÷110) km) throughout the period 1976–1990 are herewith represented as monthly contours of both amplitudes and phasesvs. height. The semi-diurnal tide has more marked seasonal variations, showing amplitudes generally larger than the diurnal ones ((10÷30) m/svs. (5÷15) m/s). The vertical wavelengths are longer in summer than in winter, at least below 100 km. Agreement with new numerical models for semi-diurnal tide at 50°N appears to be satisfactory.     

Thermal transformation of color centers in neutron-irradiated sapphire

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 56, No. 2, pp. 268–273, February, 1992.     

Product Integration Rules at Clenshaw-Curtis and Related Points: A Robust Implementation

Product integration rules generalizing the Fej?r, Clenshaw-Curtis,and Filippi quadrature rules respectively are derived for integralswith trigonometric and hyperbolic weight factors. The Chebyshevmoments of the weight functions are found to be given by well-conditionedexpressions, in terms of hypergeometric functions ₀F₁. An a priori error estimator is discussed which is shown bothto avoid wasteful invocation of the integration rule and toincrease significantly the robustness of the automatic quadratureprocedure. Then, specializing to extended Clenshaw-Curtis (ECC) rules,three types of a posteriori error estimates are considered andthe existence of a great risk of their failure is demonstratedby large scale validation tests. An empirical error estimator,superseding them for slowly varying integrands, is found toresult in a spectacular increase in the output reliability. Finally, enhancements in the control of the interval subdivisionstrategy aiming at increasing code robustness is discussed.Comparison with the code DQAWO of QUADPACK, with about a hundredthousand solved integrals, is illustrative of the increasedrobustness and error estimate reliability of our computer codeimplementation of the ECC rules.     

Inhomogeneities in silicon p-n-junctions

Latent macroscopic defects in silicon are detected by electrical and electron microscope measurements. They lead to anomalous temperature dependence of the Fermi level position and growth in the hole capture coefficient. A level with energy of 0.55 eV measured from the conduction zone controls the recombination process. It is proposed that macroscopic defects develop upon association of oxygen-silicon vacancy complexes. Action of an electron beam leads to reversible changes which increase upon multiple scanning, affecting the value of the diffusion length.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 71–75, April, 1991.