Results 1 - 10 of 43994
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[en] The hybrid version of tilted axis cranking has been used to study the existence of magnetic rotation in the ΔI=1 bands of odd-A 79,81,83,85Rb isotopes. The bands are found to be built on prolate three quasiparticle π(g9/2)(circle times)ν[g9/2(fp)1] configuration. The results exhibit a rapid onset and decline of magnetic rotation as we go from N=42 to 48. The 83Rb appears to be a better case of magnetic rotation among these four Rb isotopes
[en] We propose an alternative, more rigorous, Wigner-Kirkwood expansion for the canonical partition function for restricted rotators. The present approach is based on a basis set of periodic functions that is more appropriate than the commonly chosen plane waves. We discuss the difference between present and earlier expressions and explain why the usual approach gives acceptable results
[en] The ideal magnetohydrodynamic stability is investigated of localized interchange modes in a large-aspect ratio tokamak plasma. The resulting stability criterion includes the effects of toroidal rotation and rotation shear and contains various well-known limiting cases. The analysis allows for a general adiabatic index, resulting in a stabilizing contribution from the convective effect. A further stabilizing effect from rotation exists when the angular frequency squared decreases radially more rapidly than the density. Flow shear, however, also decreases the stabilizing effect of magnetic shear through the Kelvin-Helmholtz mechanism. Numerical simulations reveal the merits and limitations of the performed local analysis.
[en] A mechanical device of particularly simple design which can be easily installed in the vacuum chamber of X-ray spectrometers focused by the curved crystal technique, is proposed. The device rotates the crystal and the whole measuring apparatus and avoids the problems of creating vacuum encountered for more complicated mechanisms
[fr]Un dispositif mecanique de conception particulierement simple et pouvant etre aisement loge dans la boite a vide du spectrometre de rayons X a focalisation par cristal courbe est propose. Le dispositif permet la rotation du cristal et de l'ensemble de detection, en evitant des problemes pour la mise a vide rencontres avec des mecanismes plus complexes
[en] The possibility of application the transformation formulas for energy and angular momentum of fast-rotating bodies to the description of nuclear rotating spectra is discussed. The formulas follow from Lorentz-Like (tangential) transformations for coordinates providing the form-invariance of interval and describing the relativistic rotation
[en] Measurements of optical rotation of molecules in beams should now be possible with ultra-sensitive polarimeters, and would open the door to many interesting new experiments, including determination of the optical rotation of individual rotational states. The 'magic angle' is used widely in magnetic resonance, and in this paper, we introduce it for the first time to optical rotation studies. We show that although the optical rotation is in general different for different rotational states, these differences disappear if the polarimeter's light beam is applied at the 'magic angle' to the externally applied electric field used to separate the states
[en] We study the evolution of octupole collectivity in the structure of nuclear rotational bands in the framework of a Quadrupole-Octupole Rotation Model (QORM). The model formalism is capable of reproducing the different angular momentum regions in alternating parity bands together with the respective beat staggering patterns. The obtained result clearly indicates the presence of a critical angular momentum region where the separate sequences of negative and positive parity levels merge into a single octupole rotational band. The implemented model analysis outlines the mechanism of forming octupole band structure and the respective evolution of nuclear complex shape properties. Also, we have studied the effect of K-mixing and its influence on the model predictions for reduced transition probabilities in octupole bands.
[en] Introductory views are presented on the physically different but remarkably good fusion reaction performance of the dense plasma focus compared to the mainline magnetic fusion research assemblies. Reference is given to our attempt in explaining a reputed fundamental but not understood phenomenon in the focus plasma by an ion acceleration mechanism of basically the betatron type. Paradoxically, this magnetically induced plasma rotation is both contained in and denied by standard plasma equations, briefly derived and discussed with respect to validity. The neglet of the Hall term in the usual ''Ideal MHD Equations'' is shown to be in error with regard to current magnetic fusion research plasmas. Magnetically induced plasma rotation is derived from the ion fluid motion equations, from basic MHD fluid equations and by an analysis of the electro-magnetic torque distribution. General validity is proved by invoking usually overlooked consequences of the noncentral character of the forces sustaining quasi-neutrality. Arguments are given in favor of new approaches to magnetic fusion. (orig.)
[en] The Coriolis attenuation problem in the particle-rotor model is shown to be related to the BCS approximation. A model including the full recoil effect of one- and two-body terms, and with an exact diagonalization of the pairing force, is applied on four nuclei in the rare earth region known to have strongly Coriolis-perturbed isub(13/2) rotational bands. In all nuclei, the old Coriolis attenuation problem has been removed. (orig.)