Karpas

von Immanuel Löw

Graphische Requisiten und Erzeugnisse bei den Juden

Bd 1 enth. 2 Lieferungen

Beiträge zur jüdischen Alterthumskunde

von Leopold Löw

Griechische und lateinische Lehnwörter im Talmud, Midrasch und Targum : preisgekrönte Lösung der Lattes'schen Preisfrage

Samuel Krauss. Mit Bemerkungen von Immanuel Löw

The inverse problem for Schwinger pair production

The production of electron–positron pairs in time-dependent electric fields (Schwinger mechanism) depends non-linearly on the applied field profile. Accordingly, the resulting momentum spectrum is extremely sensitive to small variations of the field parameters. Owing to this non-linear dependence it is so far unpredictable how to choose a field configuration such that a predetermined momentum distribution is generated. We show that quantum kinetic theory along with optimal control theory can be used to approximately solve this inverse problem for Schwinger pair production. We exemplify this by studying the superposition of a small number of harmonic components resulting in predetermined signatures in the asymptotic momentum spectrum. In the long run, our results could facilitate the observation of this yet unobserved pair production mechanism in quantum electrodynamics by providing suggestions for tailored field configurations.

Der Verein zur Beschäftigung brotloser Arbeiter an seine Mitbürger: Als wir im Mai d. J. Ihren unermüdlichen Wohlthätigkeitssinn mit der Bitte um eine tägliche Spende von 1 bis 3 Kreuzern in Anspruch nahmen ...

Welsch (Projektbearbeiter): Rechenschaftslegung über die Spendeneinnahmen des Vereins sowie deren Verwendung (Auszahlung von Löhnen für öffentliche Erdarbeiten)

Imaging the South Pole-Aitken basin in backscattered neutral hydrogen atoms

The lunar surface is very efficient in reflecting impinging solar wind ions as energetic neutral atoms (ENAs). A global analysis of lunar hydrogen ENAs showed that on average 16% of the solar wind protons are reflected, and that the reflected fraction can range from less than 8% to more than 24%, depending on location. It is established that magnetic anomalies reduce the flux of backscattered hydrogen ENAs by screening-off a fraction of the impinging solar wind. The effects of the surface properties, such as porosity, roughness, chemical composition, and extent of weathering, were not known. In this paper, we conduct an in-depth analysis of ENA observations of the South Pole-Aitken basin to determine which of the surface properties might be responsible for the observed variation in the integral ENA flux. The South Pole-Aitken basin with its highly variable surface properties is an ideal object for such studies. It is very deep, possesses strikingly elevated concentrations in iron and thorium, has a low albedo and coincides with a cluster of strong magnetic anomalies located on the northern rim of the basin. Our analysis shows that whereas, as expected, the magnetic anomalies can account well for the observed ENA depletion at the South Pole-Aitken basin, none of the other surface properties seem to influence the ENA reflection efficiency. Therefore, the integral flux of backscattered hydrogen ENAs is mainly determined by the impinging plasma flux and ENA imaging of backscattered hydrogen captures the electrodynamics of the plasma at the surface. We cannot exclude minor effects by surface features. (C) 2015 Elsevier Ltd. All rights reserved.

Jüdischer Turnverein

Karl Löw

Der Kuß

Immanuel Löw

Der Kuß

Immanuel Löw

[Rezension]

Immanuel Löw

[Rezension]

Immanuel Löw

[Rezension]

Immanuel Löw

Zu terafim

Immanuel Löw

[Rezension]

Immanuel Löw