Negative-parity spectra for mass-18 nuclei in the dynamic-interaction propagator approach

The energy spectra and two-particle strengths of negative-parity states in mass-18 nuclei are calculated by using a Green-function formulation which includes energy-dependent two-particle interactions. The energy dependence is induced by the dynamic exchange of the octupole phonon which appears at 6.13 MeV in ¹⁶O. This state is described within a normal static particle-hole RPA. The two-body interaction parameters are chosen to provide the correct phonon energy and reasonable negative parity mass-17 and positive-parity mass-18 spectra. The negative-parity states are then calculated in a parameter-free way. In order to avoid redundant solutions or ghosts, the fermion lines must be dressed in a way consistent with the phonon exchange.     

Long-time behaviour of soliton ensembles. Part I––Emergence of ensembles

This paper is focused on the emergence of the KdV solitons from an initial harmonic excitation. In the long run this process is characterized not so much by regular soliton trains but rather by soliton ensembles. It has been shown explicitly that under indicated initial conditions the width of emerging solitons are mostly larger than the distance between maxima of wave profiles. Consequently, visible are the ensembles formed by several simultaneously interacting solitons including also hidden (virtual) solitons. The conditions for emerging such ensembles are studied over the wide range of amplitude ratios for typical dispersion parameters. Based on that analysis, it is possible to cast more light to the recurrence and periodicity in the long run (see Part II).     

Neutron scattering from Au,Hg, and Tl

The elastic and the inelastic scattering of fast neutrons from Au, Hg, and Tl was studied at incident neutron energy intervals of ~50 keV from 0.3 to 1.5 MeV. The differential elastic scattering cross sections were determined approximately every fifteen degrees from 20 to 145 degrees. The cross sections for the inelastic excitation of states in Au at 77, 270, 409, 520, 540, 740, 830, 940, 1120, and 1220 keV; in Hg at 160, 208, 440, 610, 980, and 1120 keV; and in Tl at 205, 279, 615, 680, 930, and 1080 keV were determined. The measured elastic scattering cross sections were compared with the results of optical model calculations and evidence for a decrease in the imaginary part of the potential near the doubly closed shell atA=208 was observed. The results of Hauser-Feshbach calculations, utilizing known spin and parity assignments together with those estimated from nuclear systematics, were in qualitative agreement with the measured inelastic excitation functions. The effect of resonance width fluctuations was considered in the context of the experimental results.     

Zur Chemie der Selen-Stickstoff-Verbindungen, 1. Mitt.: Die Produkte der Umsetzung von SeO2F2 mit Ammoniak

Zusammenfassung Bei der Umsetzung von SeO₂F₂ mit NH₃ entsteht unter gewissen Bedingungen ein Gemisch aus den Ammoniumsalzen des cyclischen Triselenimides und der homologen Reihe der kettenförmigen Poly-imidoselensäure-amide. Das Salz des Triselenimides läßt sich heraustrennen und verhält sich in vieler Hinsicht wie die analoge Schwefelverbindung. Die Reihe der Poly-imidoselenat-amide hydrolysiert in wäßrigen Lösungen schnell über die Monoamide zu den Poly-imidoselenaten, ebenfalls eine homologe Reihe. Durch alkalischen Abbau des cyclischen Triselenimides konnte eine Verbindung dieser Reihe, das Diimido-triselenat, rein erhalten werden.Alle trockenen Substanzen explodieren auf Schlag und beim Erwärmen auf 120–180° sehr heftig.Die Papierchromatographie erweist sich als sehr geeignetes und unbedingt notwendiges Hilfsmittel für den Nachweis und die Identifizierung der zahlreichen Individuen dieser Verbindungsklassen.Mit 8 AbbildungenAls vorläufige Mitteilung veröffentlicht anläßlich der XVII. I. U. P. A. C.-Tagung, Müchen 30.8.–6. 9. 1959, s. Versammlungsbericht, Angewandte Chemie72, 43 (1960).     

Hydroxylammonium-fluorborat (NH3OH)BF4

Ohne Zusammenfassung     

Two-body propagators with dynamic effective interactions in a many-fermion medium: I. General structure

Excitations of the many-body medium cause dynamic effective interactions between fermions. In actual calculations these interactions are almost always replaced by static approximations. In this paper a Green function approach is outlined which preserves the dynamic structure of the interactions. The central quantity is the four-vertex or two-fermion scattering amplitude Γ in the medium, which depends on three energy variables s, t, and u. Integral equations connect Γ to irreducible effective interactions in the three channels. With static interactions the s- and t-channels correspond to particle-particle and particle-hole configurations, respectively. Dynamic interactions mix these configurations. They also introduce poles in the crossed channels: the exchange of a phonon is a t-pole in the s-channel while pairons induce s-poles in the t-channel. Poles of the one-body propagator G(ω) and the two-body propagators K(s) and K(t) correspond to states of the A ± 1, A ± 2 and A-particle systems. The dynamic coupling between channels results in an intricate connection between various aspects of the many-fermion problem.     

Drug-liposome distribution phenomena studied by capillary electrophoresis-frontal analysis

The potential of using CE frontal analysis (CE-FA) for the study of low-molecular-weight drug-liposome interactions was assessed. The interaction of bupivacaine, brompheniramine, chlorpromazine, imipramine, and ropivacaine with net negatively charged 80/20 mol% 1-oleoyl-2-palmitoyl-sn-glycero-3-phosphocholine/egg yolk phosphatidic acid liposome suspensions in HEPES buffer at pH 7.4 was investigated. The fraction of free drug as a function of lipid concentration was measured and apparent liposome - buffer distribution coefficients were determined for the basic drug substances. The distribution coefficients increased in the order ropivacaine, bupivacaine, brompheniramine, imipramine, and chlorpromazine. The developed CE method was relatively fast allowing estimates of drug-liposome affinity to be obtained within 15 min. CE-FA may have the potential to become a valuable tool for the characterization of drug-liposome interactions in relation to estimation of drug lipophilicity and for the evaluation of drug distribution in liposomal drug delivery systems.