SSNTD and radiochemical studies on the transmutation of nuclei using relativistic ions

Extended targets were irradiated for transmutation studies with relativistic heavy ions. For this, a metal core was surrounded by a paraffin moderator. The metal is either copper or lead and it was irradiated with deuterium, alpha, or carbon beams of 1.5 or 3.7 GeV/u at the SYNCHROPHASOTRON, LHE, JINR, Dubna, Russia. During this irradiation copious amounts of secondary neutrons are produced and studied with SSNTD detectors and radiochemical sensors, for example ¹³⁹La (n, γ) ¹⁴⁰La→β⁻. The yield of reaction products allows an estimation of secondary neutron fluxes. The yields of all kinds of reactions produced with deuterium and alpha beams obey to some extent the law of “limiting fragmentation”, i.e. they show little influence on the energy and the kind of incoming particles. However, one observes with 44 GeV ¹²C ions always enhanced nuclear cross-sections induced by secondary particles. This behavior could not be confirmed with theoretical estimations based on the Dubna Cascade Model in its Cascade Evaporation Model version (DCM-CEM). Finally, some results for transmutation studies on ¹²⁷I and Cu will be presented.     

Binaural summation and lateralization of transients: a combined analysis

Subjects judged the loudness and the lateral position of dichotic transient signals, which were presented at equal and unequal levels, synchronously and asynchronously, to the two ears. Binaural loudness summation of clicks does not obey a law of linear addition: It is partial at low level and superadditive at high level. Supersummation is greater for interaurally delayed clicks than for coincidental ones. The relation between click loudness and sound pressure (over moderate SLs) can be described as a power function with a greater exponent for the binaural function. Lateral positions spread over a greater range for interaural level differences than for interaural time differences. The time-intensity trading ratio was greater than is typically reported for tones. When sound lateralization was induced by interaural time difference, but not by intensity difference, a virtually perfect negative correlation between loudness and extent of off-center displacement existed.     

On combinatorial optimization problems on matroids with uncertain weights

In this paper the combinatorial optimization problem on weighted matroid is considered. It is assumed that the weights in the problem are ill-known and they are modeled as fuzzy intervals. The optimality of solutions and the optimality of elements are characterized. This characterization is performed in the setting of possibility theory. A method of choosing a solution under uncertainty is also proposed.     

Struktur und reaktivität des koordinativ überladenen komplexes dichloro-η5 -cyclopentadienyl- tris(tetrahydrofuran)ytterbium(III)

The crystal and molecular structure of (η⁵ -C₅H₅)YbCl₂(THF)₃ (1), which crystallizes e.g. from solutions of [(C₅H₅)₂YbCl]₂ in THF, fully corresponds to the structure of the previously examined Er-homologue. In accordance with its rather high SAS-value (0.784), 1 loses spontaneously two THF ligands when exposed to toluene.     

Liouville-type theorems for some complex hypoelliptic operators

It is shown that the natural analogue of Liouville's theorem holds for the well-known hypoelliptic operators _α (for ¦α¦ < n) introduced and studied by Folland and Stein on the Heisenberg group H_n. Since these operators are non-real for α ≠ 0, the usual methods of potential theory fail and are replaced by an explicit use of the fundamental solution.     

Apertureless near field optical microscopy: a contribution to the understanding of the signal detected in the presence of a background field

Apertureless scanning near field optical microscopy techniques have become a common way of studying surface samples. By using a nano-probe that scatters the electromagnetic non-propagative waves emerging from a given sample, this microscopy provides optical images with a resolution beyond the diffraction limit. Despite a great diversity of works covering a wide variety of physical domains, the formation of the images obtained is not yet fully understood. The purpose of this letter is to assess the influence of the tip position and imposed oscillation of the tip in apertureless SNOM when a background field is added to the scattered near field. We propose a simple analytical model which enables us to account for the experimental results and explains how, depending on the experimental conditions, the near field signal can totally disappear or, on the contrary, be greatly enhanced.