Messung der γ-Winkel-Verteilung nach dem Neutroneneinfang an polarisierten Tb159-Kernen

The anisotropy of high-energy capture γ-rays from polarized Tb¹⁵⁹ nuclei was measured. Polarization of Tb¹⁵⁹ was achieved by cooling single crystals of Terbium-Ethylsulfate toT=0.35 °K in an external field of 4 kOe. With the results of this measurement, it was possible to deduce the spins of 11 levels in Tb¹⁶⁰ between 64 keV and 767 keV. Furthermore theQ-value of the reaction Tb¹⁵⁹(n, γ) Tb¹⁶⁰ was determined to beQ=(6,374.0± 1.5) keV.     

Pulsed laser deposition of polymers doped with fluorescent molecular sensors

Pulsed laser deposition (PLD) has been used to obtain thin films of poly(methyl-methacrylate), PMMA, and polystyrene, PS, doped with fluorescent probes based in the amino aromatic compounds S6, DMA-2,4, Dans and Acrid-acryl. These compounds, both in solution and inserted in polymeric films, show solvatochromic emission band shifts upon changes of pH, polarity and viscosity in their micro-environment and, prepared in thin films, could prove advantageous for use as sensors of the presence of contaminating environmental agents. Deposits, obtained by irradiating targets consisting in films of doped PMMA and PS with a Ti:sapphire laser (800 nm, 120 fs pulse), were analyzed by optical and environmental scanning electron microscopy, fluorescence microscopy, laser-induced fluorescence, micro-Raman spectroscopy and flow injection analysis-mass spectrometry. Results show the effective transfer of the polymer and the probe to the substrate and the high dependence on film structure on the polymer used in the targets. Irradiation with a KrF laser (248 nm, 20 ns) of Dans-doped targets only produced deposits when using PMMA for target preparation. Results are discussed in terms of the participation of multiphoton processes in the fs IR irradiation, the influence of the linear absorption coefficient of the targets and of the different contributions of thermal and chemical effects in the IR femtosecond and UV nanosecond domains. PACS 81.15.Fg; 61.82.Pv     

A note on the zero sets ofA(B) andA ∞ B) in transverse curves

Summary In this note we give two constructive proofs concerning the zero sets ofA(B) andA ^∞(B) of transverse curves contained in the unit sphere of C ⁿ .

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Riassunto Si forniscono due prove costruttive riguardanti l’insieme degli zeri diA(B) eA ^∞(B) delle curve traverse contenute nella sfera di C ⁿ .

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This work has been supported in part by the grant PB85-0374 from the C.I.C.Y.T.     

Benzomorphan related compounds. II. New synthesis route to thienomorphans

A new synthesis route to α-2,5,9-trimethylthieno[3,2-f]morphan and two analogous compounds from cyanopyridines and 2-thienyllithium is described. Spectroscopic data of these substances and their intermediates are included.     

The quasimolecular 1sσ orbital in collision systemsα(Z 1+Z 2)≳1, its excitation and spectroscopy

An analytical formula for the excitation probability of the quasimolecular 1sσ orbital as a function of the impact parameterb is derived for collision systems withα(Z ₁+Z ₂)?1. This formula describes well all existing experimental data for those collision systems except for the heaviest system Pb+Cm (Z ₁+Z ₂=178) at impact parametersb?40 fm. It is discussed in which way energies of the quasimolecular 1sσ orbital can be extracted from experimental 1sσ vacancy production data.     

Quantitative line selection with the Kalman filter approach for inductively coupled plasma atomic emission spectrometry

With the Kalman filter approach, the true detection limit (i.e. the detection limit in the sample solution) only depends on the height of the total background signal, and is not determined by the uncertainties in interfering background signals. Based on the background equivalent interferent concentration, the true detection limit can be directly estimated in sample solutions containing various amounts of interferent. This eases the application of the true detection limit as quantitative criterion for line selection. Following this approach, quantitative line selection is demonstrated for Pb and Cd determinations in river sediments (Fe interferences).     

Un théorème de prolongement pour des fonctions analytiques

Sans résumé