Decay energy of183Re→183W

The electron capture decay energy of¹⁸³Re has been determined from the fraction ofK-capture in the transition to the 453.08 keV level in¹⁸³W by delayed coincidences. From this value the total decay energy from₁₈₃Re→¹⁸³W is obtained to beQ=555 _?7 ⁺⁹ keV according to the theory ofBrysk andRose with corrections ofBahcall. The resulting logft values and consequences for the decay scheme are discussed.     

Collective structures in185Hg

Excited states of¹⁸⁵Hg have been investigated via the¹⁶¹Dy(²⁸Si, 4n) reaction at 145 MeV. In-beamγ-ray spectroscopic studies have been performed with the “Château de Cristal” 4π-multidetector array. A level scheme of¹⁸⁵Hg has been established. Shape coexistence, still present in¹⁸⁵Hg like in the neighbouring Hg isotopes, manifests itself through a weakly populated decoupled band built on the 13/2⁺ isomer and three strongly-coupled bands built on the prolate 1/2^? [521], 7/2^? [514], and 9/2⁺ [624] Nilsson states.     

Koinzidenzmessungen am Ta183→W183-Zerfall mit Hilfe eines eisenfreien Orangen-Beta-Spektrometers

The decay of Ta¹⁸³ has been studied using an iron-free orange-type beta-ray spectrometer. Beta-gamma coincidence measurements confirm the proposed level scheme of W¹⁸³. The recently discovered 313.28 keV transition has been inserted into the level scheme and a new single particle state 9/2⁺ [624] at 622.7 keV is proposed. The isomeric level at 309.4 keV is shown to have spin and parity 11/2⁺.     

Asymmetry parameters in183W and182W using mice detection with a crystal monochromator

Using exceptionally high intensity Mössbauer sources (～ 1–100 Ci) of¹⁸²Ta and¹⁸³Ta, we have measured the Mössbauer effect for the 46.5 and 99.1 keV transitions of¹⁸³W and the 100.1 keV transition of¹⁸²W. Using a microfoil internal conversion electron (MICE) /1/ detector capable of operation at low temperatures, and a LiF crystal monochromator, we obtain effects of nearly 600% for the 46.5 keV transition and 3 1/2% and 6% for the other two cases, while standard transmission measurements typically yield much smaller signal-to-background ratios. With this technique we have measured the asymmetry term in the conversion electron spectra. To our present level of accuracy the results are in agreement with theoretical calculations of interference parameters /2/. Our results do not agree with earlier measurements /3/ on this transition, which are grossly at variance with theoretical calculations of the interference parameter.     

Collective band structures in106,107Cd

Levels in^106,107Cd have been studied with the reactions⁸²Se(³⁰Si, 5-6n)^106,107Cd. The bands observed in the experimental are mostly due to the N=4 and h_11/2 neutron structures.     

Collective transport in locally asymmetric periodic structures

In this paper we give an overview of the cooperative effects in fluctuation driven transport arising from the interaction of a large number of particles. (i) First, we study a model with finite-sized, overdamped Brownian particles interacting via hard-core repulsion. Computer simulations and theoretical calculations reveal a number of novel cooperative transport phenomena in this system, including the reversal of direction of the net current as the particle density is increased, and a very strong and complex dependence of the average velocity on both the size and the average distance of the particles. (ii) Next, we consider the cooperation of a collection of motors rigidly attached to a backbone. This system possesses dynamical phase transition allowing spontaneous directed motion even if the system is spatially symmetric. (iii) Finally, we report on an experimental investigation exploring the horizontal transport of granular particles in a vertically vibrated system whose base has a sawtooth-shaped profile. The resulting material flow exhibits complex collective behavior, both as a function of the number of layers of particles and the driving frequency; in particular, under certain conditions, increasing the layer thickness leads to a reversal of the current, while the onset of transport as a function of frequency occurs gradually in a manner reminiscent of a phase transition. (c) 1998 American Institute of Physics.     

Collective structures and smooth band termination in109Sn

Six rotational bands up to energies E _x =24.7 MeV and spinsj ^π=(79/2^?) have been identified in¹⁰⁹Sn using the GAMMASPHEREγ-detector array. Four of the bands show smoothly decreasing dynamic moments of inertia at rotational frequencies?ω>0.6 MeV. The bands arise at medium spins from a coupling of a valence d_5/2, g_7/2 or h_11/2 neutron to the deformed 2p2h proton excitation of the Z=50 core¹⁰⁸Sn. At very high?ω these bands show the typical behaviour of smoothly terminating bands, i.e. a gradual alignment of the angular momenta of the valence particles and holes corresponding to a transition from high collectivity to noncollective states.     

Collective structures and smooth band termination in 109Sn

Six rotational bands up to energies E _x = 24.7 MeV and spins J^π=(79/2^?) have been identified in ¹⁰⁹Sn using the GAMMASPHERE γ-detector array. Four of the bands show smoothly decreasing dynamic moments of inertia at rotational frequencies ?ω > 0.6 MeV. The bands arise at medium spins from a coupling of a valence d_5/2, g_7/2 or h_11/2 neutron to the deformed 2p2h proton excitation of the Z=50 core ¹⁰⁸Sn. At very high ?ω these bands show the typical behaviour of smoothly terminating bands, i.e. a gradual alignment of the angular momenta of the valence particles and holes corresponding to a transition from high collectivity to noncollective states.     

Angular- and temperature-dependent RSMR on myoglobin using 183W and 57Fe

Myoglobin crystals are investigated by Rayleigh scattering of Mössbauer radiation at T = 87 K and T = 300 K and angles up to sin(?)/λ = 0.44 Å^?1. The results are analysed in terms of normal modes.     

Statistical modeling of intrinsic structures in impacts sounds

This paper presents a statistical data-driven method for learning intrinsic structures of impact sounds. The method applies principal and independent component analysis to learn low-dimensional representations that model the distribution of both the time-varying spectral and amplitude structure. As a result, the method is able to decompose sounds into a small number of underlying features that characterize acoustic properties such as ringing, resonance, sustain, decay, and onsets. The method is highly flexible and makes no a priori assumptions about the physics, acoustics, or dynamics of the objects. In addition, by modeling the underlying distribution, the method can capture the natural variability of ensembles of related impact sounds.     

Confirmation of the giant hyperfine anomaly of the system184W2+-183W g by new spin-echo experiments with183WFe and remarks on possible explanations

Spin-echo measurements on¹⁸³W were performed with dilute alloys of W (0.1, 0.25, 0.5 and 1 at %) in Fe. The result for the hyperfine field:B _4.2K ^hf =(?)62 · 54 (3) T agrees with the old data of Kontani and Itoh, but the accuracy is much better. The giant hyperfine anomaly of¹⁸³W with respect to¹⁸⁴W₂₊ observed by Alzner et al. is thus confirmed and the errors are reduced to:¹⁸⁴W₂₊Δ¹⁸³W_g=+0.150(31). This is the first case of a very large hyperfine anomaly in electronic hyperfine fields which is not caused by the pathological cancellation of orbital and spin magnetism in jackknifep _1/2 ord _3/2 single proton configurations. A detailed discussion shows that the large hyperfine anomaly may be related to the anomalously small magnetic dipole moment of¹⁸³W. Our result should stimulate further theoretical work with the aim to understand this magnetic moment as well as the giant hyperfine anomaly.