Bismuth-fission detectors for high energy nucleons: I. Registration characteristics

There is considerable current interest in the detection of high energy nucleons around accelerators, spallation sources, and in cosmic rays. A detector that has its principal response at nucleon-energy above 50 MeV is provided by the fission of Bi-209. The problem of limited sensitivity has been solved by: a) spark counting large detector areas, b) reducing the detector background by special counting procedures, c) using many replicates of a thin track detector between two ²⁰⁹Bi-radiators. Finally, the registration efficiency has been evaluated and determined experimentally using proton beams with energies of 100, 150, and 250 MeV.     

The weak Dirichlet problem for Baire functions

Let be a simplex and a compact subset of the set of all extreme points of . We show that any bounded function of Baire class on can be extended to a function of affine class on . Moreover, can be chosen in such a way that .

     

Fällung der anionischen Nitratkomplexe von Ce4+ und Pu4+ mit Cetylpyridiniumnitrat

Anionic nitrato complexes of Ce⁴⁺ and Pu⁴⁺ react with cetylpyridinium nitrate under formation of sparingly soluble salts. Depending on thepH, both metals are precipitated as hexanitrato complexes or octanitrato complexes or as the corresponding double salts.

     

Elektrochemische Eigenschaften der Konzentrationskette KCl-Lösung/Methyl-isobutylketon/KCl-Lösung

Zusammenfassung Um Aussagen über das Potential einer Konzentrationskette mit einer organischen Flüssigkeit, deren Moleküle stark polarisiert sind, zu bekommen, wurde das System KCI-Lösung/Methyl-isobutylketon/KCl-Lösung untersucht. Für die Interpretierung der Ergebnisse im System dieser Art liegen zwei Theorien vor: Die Theorie des Diffusionspotentials und die Adsorptionstheorie. Es wurde festgestellt, daß das Diffusionspotential in der untersuchten Kette klein und das gemessene Potential durch die Differenz der Phasengrenzpotentiale gegeben ist.

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Summary We measured the electrical potential across the cell KCl-solution/methylisobutylketone/KCl-solution. The origin of the potential can be explained by two theories: the theory of the diffusion potential and the adsorption theory. The, measurements demonstrate that the diffusion potential is negligible and that the main part of the total potential is given by the difference of the interfacial potentials.

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Mit 4 Abbildungen und 2 Tabellen     

Meßanordnung für die Untersuchung der Elektrokapillaritätserscheinungen an der Phasengrenze Öl/Elektrolytlösung

Zusammenfassung In einer vorliegenden Arbeit ist eine neue Methode für die Untersuchung des Elektrokapillaritätseffekts an der Phasengrenze Öl/Elektrolytlösung beschrieben. Die Meßanordnung ermöglicht, aus dem Serienwiderstand des Systems Elektrolytlösung/Öl/Elektrolytlösung den Potentialabfall über der Phasengrenze zu ermitteln und die Elektrokapillaritätskurven als eine Funktion _G von U darzustellen. Die Methode wurde durch die Messung an einem System von Methyl-isobutylketon (TDPJ)/Elektrolytlösung (Natriumhalogenide) demonstriert.

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Summary This paper describes a new method to investigate the electrocapillary phenomena at an interface oil/electrolyte solution. This method allows to determine the potential drop U through the interface by measuring the resistance of the system electrolyte solution/oil/electrolyte solution and to plot the electrocapillary curves _G as a function of U. To give an example we show measurements at the system methyl-isobutylketon (ammonium salt)/electrolyte solution (halide salts).

     

Third-harmonic generation in slow-light chalcogenide glass photonic crystal waveguides

We demonstrate third-harmonic generation (THG) in a dispersion-engineered slow-light photonic crystal waveguide fabricated in AMTIR-1 chalcogenide glass. Owing to the relatively low loss and low dispersion in the slow-light (c/30) regime, combined with the high nonlinear figure of merit of the material (～2), we obtain a relatively large conversion efficiency (1.4×10(-8)/W(2)), which is 30× higher than in comparable silicon waveguides, and observe a uniform visible light pattern along the waveguide. These results widen the number of applications underpinned by THG in slow-light platforms, such as the direct observation of the spatial evolution of the propagating mode.     

On the dirichlet problem of extreme points for non-continuous functions

Let X be a compact convex set and f be a bounded function defined on the set ext X of extreme points of X. We present a necessary and sufficient condition ensuring that f can be extended to a strongly affine Baire-α function. This generalizes a result of E. M. Alfsen from [2]. We also consider extensions of vector-valued mappings, thus generalizing another result of E. M. Alfsen.