Search results for "Rigid rotor"
showing 7 items of 7 documents
Conformational behaviour of 2,2?-bipyrrole
1986
The rotational potential around the interannular bond in 2,2′-bipyrrole has been calculated making use of standard minimal STO-3G and split valence 4-31G basis sets. Geometrical optimization concerning the most significant interannular internal parameters has been performed with both basis sets. The trans conformer is predicted to be more stable than the cis. The minimal basis set predicts the existence of a cisoid-gauche minimum which after limited optimization becomes very shallow and it seems to be an artifact of the rigid rotor approximation. At 4-31G level, both the trans and cis conformers represent maxima in the potential curve and two gauche minima appear at θ=46.0° and θ=147.6°, th…
Rotational bands in99Sr
1984
The β-decay of 59 ms99Rb has been studied at OSTIS. As is confirmed by RPA calculations with Nilsson model wave functions, the lowest energy levels in99Sr are consistent with rotational bands built on the [411 3/2], [413 5/2] and [422 3/2] Nilsson neutron configurations at 0, 423 and 1071 keV, respectively. All three bands have similar values of the inertial parameter ħ2/2θ indicating a nearly rigid rotor.
First evidence for the 2+ level in the very neutron-rich nucleus102Sr
1995
Evidence for the 2+ level in102Sr is obtained from theβ-decay of102Rb, mass separated at the ISOLDE facility. The energy of 126 keV and the collectivity of the 2+→0+ transition indicate that102Sr is a strongly deformed rigid rotor. In addition, a sizeable lifetime is measured for the 94 keV transition in102Y.
INFLUENCE OF UNCERTAINTIES ON PD TUNING
2013
The aim of this work is to present a method for tuning the parameters of PD controller under the influences of the uncertainties, in order to stabilize the position of a rotor supported by active magnetic bearings (AMBs). The uncertainties are relative to mass, transverse and polar moment of inertia of the rotor. The introduction of the uncertainties is due to an incomplete modeled dynamic of the system or in the case the system being subjected to a parametric variation. The presence of the uncertainties produces a set of differences among the values of the output. Poles displacement method is used to reach the asymptotically stability condition characterized by a periodic oscillation durin…
INFLUENCE OF UNCERTAINTIES ON ROTATING FLEXIBLE SHAFT SUSPENDED BY 4-AXIS RADIAL ACTIVE MAGNETIC BEARINGS µ-SYNTHESIS AND LOOP-SHAPING-DESIGN
2012
This paper shows a comparison about dynamic behavior of a rotating shaft when it is suspended by 4-axis radial active magnetic bearing system. The active magnetic suspension is obtained by two different controllers which realize the robust stability and robust performance. The control systems used are µ-synthesis and loop shaping design procedure. Each of these controllers is characterized by fourinput and four output signals and the introduction of uncertainties on displacement gain and current gain is justified by the simple fact that during the time the component which constitutes these gains can be subjected to torn and worn which can lead the entire system to instability phenomena. The…
ROBUST CONTROL FOR A SUSPENDED ROTATING SHAFT BY RADIAL ACTIVE MAGNETIC BEARINGS
2011
This paper shows a comparison based on dynamic behaviour of a rotating shaft when it is suspended by 4-axis active magnetic bearings under several control systems. The control systems used are μ-synthesis, loop shaping design procedure and Sub(H∞) robust control with the introduction of uncertainties on position and current gains of the actuators. Each of these controllers is characterized by four input signals and four output signals and the introduction of uncertainties on displacement gain and current gain is due to torn and worn of the components during the time, which can lead the entire system to instability phenomena. The comparison of the performances is obtained through the introdu…
Field-free one-dimensional alignment of ethylene molecule
2006
International audience; We report an experimental study of non-adiabatic laser-induced molecular alignment of ethylene (C2H4) using a linearly polarized short laser pulse of moderate intensity. The information about the confinement of the C=C bond axis along the direction of the applied electric field is obtained by measuring the depolarization of a second short pulse of weak intensity interacting with the molecules after they have been exposed to the first pulse. The experimental data are compared with the numerical simulation of the Schr¨odinger equation written for the non-resonant interaction of an asymmetric top rigid rotor with a linearly polarized electric field. The field-free align…