QED polarization asymmetries fore + e − scattering due to helicity flips

The polarization asymmetries for thee ⁺ e ^? scattering with polarized incoming and outgoing beams, which are proportional to the amplitudes? ₅ describing one helicity flip and? ₅ describing two helicity flips, have been calculated including their pure QED radiative corrections. These asymmetries are partly large and can be observed well at low energies.     

Über den Anstieg von Flüssigkeiten in vertikalen makroskopischen Modellrohren unter Weltraumbedingungen

übersicht Der Anstieg einer Flüssigkeitssäule in makroskopischen kreiszylindrischen und konischen Rohren unter verminderter Schwereeinwirkung wird theoretisch und experimentell (Höhenforschungsrakete) untersucht. Das Verhalten von Flüssigkeiten unter Weltraumbedingungen (Restschwere, Mikrogravitation) ist von besonderem Interesse in der Raumfahrttechnik. Unter Berücksichtigung aller wesentlichen Kräfte ergibt sich trotz verschiedener Vereinfachungen in den theoretischen Ansätzen eine gute übereinstimmung zwischen numerischen Resultaten und den Meßergebnissen.

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On the rise of liquid columns into vertical tubes subjected to zero-gravity

Summary Theoretical and experimental information is given on the capillary rise of liquid into macroscopic vertical round tubes subjected to reduced gravity. The response in a low gravitational environment is of particular interest in studying the behaviour of liquid systems for space vehicles. An approximate analysis is presented to predict the transient rise and to interpret the experimental data. Agreement between numerical and experimental results is very good.

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Herrn Professor em. Dr. Dr.-Ing. E. h. Eberhard Mettler zur Vollendung des 75. Lebensjahres gewidmet     

Global attractors for the three-dimensional Navier-Stokes equations

In this paper we show that the weak solutions of the Navier-Stokes equations on any bounded, smooth three-dimensional domain have a global attractor for any positive value of the viscosity. The proof of this result, which bypasses the two issues of the possible nonuniqueness of the weak solutions and the possible lack of global regularity of the strong solutions, is based on a new point of view for the construction of the semiflow generated by these equations. We also show that, under added assumptions, this global attractor consists entirely of strong solutions.     

Cesium vapor laser with transverse pumping by multiple laser diode arrays

We have demonstrated a Cs vapor laser that utilizes fifteen laser diode arrays for transverse pumping of the gain medium. A maximum output power of 28 W was achieved with a total optical to optical efficiency of 14% and a slope efficiency of 15%. Transverse pumping allows scaling of such a laser system to a higher power level by simple increasing of the gain medium volume and the number of pump sources.     

Infrared diode laser spectroscopy of nitric oxide

The lineshapes of the rotational-vibrational lines $\text{R(}\text{17}\text{2}\text{)}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{, R(}\text{19}\text{2}\text{)}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$, and $\text{R(}\text{19}\text{2}\text{)}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ of nitric oxide were measured using a PbS_0.61Se_0.39 diode laser. These lineshapes were measured for a NO/N₂ mixture and an NO/H₂O/N₂ mixture at atmospheric pressure. This is the first high resolution spectroscopic mearuement of the rotational-vibrational lineshape of NO broadened by H₂O. The effect of the H₂O is to broaden the lines, increasing the halfwidth by up to 30% for a 10% volume concentration of H₂O. For the case of NO broadened by N₂, the measured linestrengths for the $\text{R(}\text{19}\text{2}\text{)}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ and $\text{R(}\text{17}\text{2}\text{)}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ lines are within 2% of previously published values.     

Existence of dichotomies and invariant splittings for linear differential systems I

This paper is concerned with linear time-varying ordinary differential equations. Sufficient conditions are given for the existence of an exponential dichotomy for a class of equations which includes those with Bohr almost-periodic coefficients. The problem is treated in the context of linear skew-product flows, where it becomes clear how to generalize to the case of fiber-preserving flows on vector bundles. Both continuous and discrete flows are treated and the results apply to the linearized variational equation for a time-varying vector field on a manifold as well as the linearization of a diffeomorphism acting on a manifold. Sufficient conditions are given for a diffeomorphism on a manifold to be an Anosov diffeomorphism. For linear skew-product flows arising from ordinary differential equations our theory is a partial generalization of Floquet theory to the almost-periodic case.