New aspects of the rotational model in25Mg

1974 ◽  
Vol 266 (1) ◽  
pp. 55-64 ◽  
Author(s):  
H. Röpke ◽  
G. Hammel ◽  
W. Brendler ◽  
P. Betz ◽  
V. Glattes
Keyword(s):  
Rotational Model

Branching Ratios and Lifetimes of 25Mg Levels below 5.2 MeV

1974 ◽  
Vol 52 (23) ◽  
pp. 2329-2342 ◽  
Author(s):  
R. W. Ollerhead ◽  
D. C. Kean ◽  
R. M. Gorman ◽  
M. B. Thomson
Keyword(s):  
Doppler Shift ◽  
Gamma Ray ◽  
Branching Ratios ◽  
Surface Barrier ◽  
Surface Barrier Detector ◽  
Rotational Model ◽  
Rotational Bands ◽  
Barrier Detector ◽  
Combined Data

All levels below 5.2 MeV in 25Mg have been studied using the reaction 25Mg(p, p′γ). In-elastically scattered protons were detected in an annular surface barrier detector located at 180°; coincidence gamma-ray spectra were obtained at Ge (Li) detector angles of 90°, 45°, and 135°. Level energies were determined from unshifted gamma-ray energies recorded in the 90° spectra. Lifetimes were obtained from the attenuated Doppler shift of gamma-ray energies recorded in spectra taken at forward and backward angles. Branching ratios were deduced from the combined data of all three angles. The identification of levels as members of rotational bands is discussed, and transition strengths deduced from the present measurements are compared with predictions of the simple rotational model.

A HYBRID MODEL ON HYSTERESIS LOOP AND COERCIVITY IN NANOSTRUCTURED PERMANENT MAGNETS

2006 ◽  
Vol 05 (04n05) ◽  
pp. 627-631 ◽  
Author(s):  
M. J. SUN ◽  
G. P. ZHAO ◽  
J. LIANG ◽  
G. ZHOU ◽  
H. S. LIM ◽  
...  
Keyword(s):  
Thin Films ◽  
Domain Wall ◽  
Grain Boundary ◽  
Magnetic Moment ◽  
Permanent Magnets ◽  
Hysteresis Loops ◽  
Bulk Materials ◽  
Rotational Model ◽  
Moment Distribution ◽  
Coercivity Mechanism

A simplified micromagnetic model has been proposed to calculate the hysteresis loops of nanostructured permanent magnets for various configurations, including thin films, exchange-coupled double-layer systems and bulk materials. The reversal part of the hysteresis is based on the Stoner–Wohlfarth coherent rotational model and the coercivity mechanism is due mainly to the motion of the transition region (a domain wall like magnetic moment distribution in the grain boundary). The elements of nucleation and pinning models are also incorporated.

Friction Induced Vibrations in Aircraft Disk Brakes

1997 ◽  
Author(s):  
Lisle B. Hagler ◽  
Per G. Reinhall
Keyword(s):  
Friction Coefficient ◽  
Multiple Scales ◽  
Primary Resonance ◽  
Rotational Model ◽  
Stick Slip ◽  
Numeric Simulation ◽  
Constant Friction ◽  
The Stability ◽  
Rotor Stiffness ◽  
Friction Induced Vibration

Abstract This paper presents a detailed analysis of the dynamic behavior of a single rotor/stator brake system. Two separate mathematical models of the brake are considered. First, a non-rotational model is constructed with the purpose of showing that friction induced vibration can occur in the stator without assuming stick-slip behavior and a velocity dependent friction coefficient. Self-induced vibrations are analyzed via the application of the method of multiple scales. The stability boundaries of the primary resonance, as well as the super-harmonics and sub-harmonics are determined. Secondly, rotational effects are investigated by considering a mathematical brake model consisting of a spinning rotor engaging against a flexible stator. Again, a constant friction coefficient is assumed. The stability of steady whirl is determined as a function of the system parameters. We demonstrate that only forward whirl is stable for no-slip motion of the rotor. The interactions between chatter, squeal, and rotor whirl are investigated through numeric simulation. It is shown that rotor whirl can be an important source of the torsional oscillations (squeal) of the stator and that the settling time to no-slip decreases as the ratio of the stator to rotor stiffness is increased.

PROPERTIES OF THE 7.02-MeV AND 10.65-MeV LEVELS OF 20Ne

1967 ◽  
Vol 45 (6) ◽  
pp. 2133-2143 ◽  
Author(s):  
P. J. M. Smulders ◽  
C. Broude ◽  
A. E. Litherland
Keyword(s):  
Angular Correlation ◽  
Excellent Agreement ◽  
Amplitude Ratio ◽  
Branching Ratio ◽  
Rotational Model ◽  
Particle Counter ◽  
Correlation Techniques

The 7.02-MeV level of 20Ne has been studied by the I2C(12C, αγ)20Ne reaction, using angular correlation techniques, with a particle counter and six Nal crystals. The spin and parity of this level were determined to be 4−. The branching ratio of the decays to the 5.63, 4.97, and 4.25 MeV levels was found to be 22:65:13. The transition to the 5.63-MeV state (4− → 3−) is an almost pure E2 transition with an M1/E2 amplitude ratio of 0.03 ± 0.03. The branching ratio of the E2 transitions to the 5.63-MeV 3− level and the 4.97-MeV 2− level is in excellent agreement with predictions from the rotational model and also with SU3 calculations.Similar measurements on the 10.65-MeV level in 20Ne support the tentative 6− assignment to this level.

scholarly journals Excitation of the Ground-State Rotational Band in 28Si by Inelastic Scattering of 25.25 MeV Polarized Protons

1973 ◽  
Vol 51 (12) ◽  
pp. 1293-1299 ◽  
Author(s):  
R. de Swiniarski ◽  
H. E. Conzett ◽  
C. R. Lamontagne ◽  
B. Frois ◽  
R. J. Slobodrian
Keyword(s):  
Inelastic Scattering ◽  
Cross Sections ◽  
Ground State ◽  
Optical Potential ◽  
Great Sensitivity ◽  
Angular Distributions ◽  
Rotational Model ◽  
Coupled Channels ◽  
Polarized Protons ◽  
State Band

Angular distributions of the analyzing power and cross sections have been measured for the elastic and inelastic scattering of 25.25 MeV protons exciting the K = 0+ ground-state band in 28Si. Good agreement with experiment is obtained in the coupled-channels formalism on the basis of the rotational model with a quadrupole deformation β2 = −0.40 (oblate) and a hexadecapole deformation β4 = +0.15. The calculations show the great sensitivity of the experimental results to both the magnitude and sign of the quadrupole and hexadecapole deformations. Equivalent fits of the data were obtained either by keeping the deformation length of the various deformed terms of the optical potential constant (δ0 = β0R0 = βIRI = βLSRLS) or by increasing the deformation of the spin–orbit optical potential relative to the central potential by a factor of 1.5 (βLS = 1.5βcent).

Microscopic Uni-axial Bohr-Mottelson Rotational Model

2010 ◽  
Author(s):  
P. Gulshani ◽  
Ricardo Alarcon ◽  
Phil Cole ◽  
Andres J. Kreiner ◽  
Hugo F. Arellano
Keyword(s):  
Rotational Model
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