Double-couple model

The corresponding moment tensor and a double-couple model are given in Fig. 7.17 (b) and Fig. 7.17 (c), respectively. Again, one couple force is irrational, because the equilibrium of forces is violated. From Eq. 7.27, it is readily found that the double-couples forces (off-diagonal components) just correspond to shear stresses in the stress tensor. 

Fig. 7.17. (a) Dislocation model for a shear crack, (b) the corresponding moment tensor and (c) double-couple model. 

Reactive double-slit model (RDSM), non-adiabatic coupling, Longuet-Higgins phase-based treatment, two-dimensional two-surface system, scattering calculation, 150-155... 

Protein Sequencing. The xylanase protein sequence was obtained by stepwise automated E an degradation ter an initial double-coupling protocol, using an Applied Biosystems model 470A gas-phase sequenator equipped with an on-line Applied Biosystems model 120A PTH-amino acid analyzer 13). 

The data have been analyzed within the described coupled double-well model. The protons are represented by pseudospins whereas the C4O4 unit displays highly nonlinear polarizability effects, which are taken into account within the framework of the nonlinear polarizability model [17,20]. As compared to KDP-type ferroelectrics the model is less complex [26,27] since the... 

The active Irunsport of chloride has also been demonstrated across ihe wall of the IVog stomach, rat ileum, dog ileum, and the human ileum. Experiments have produced a double exchange model in which bicarbonate secretion and chloride absorption are linked hy an isoelectric mechanism to hydrogen ion secretion and sodium absorption across the human ileum. In 1972. a group of researchers proposed a similar model of coupled transport... 

The calculations present here among the first to give serious consideration to the competing effects of spin coupling and electron delocalization in polynuclear transition metal clusters. The qualitative features support the "double exchange" model put forth to describe experimental spectra (7), although we do not postulate a particular mechanism in these calculations--the results arise solely from analysis of computed total energies for various states. 

H. Koch, O. Christiansen, R. Kobayashi, P. Jorgensen, and T. Helgaker, Chem. Phys. Lett., 228, 233 (1994). A Direct Atomic Orbital Driven Implementation of the Coupled Cluster Singles and Doubles (CCSD) Model. 

No low level of / = 0 is predicted by these schemes other than the ground state, but it arises naturally as a dilational state in the alpha particle model. This model (Sect. 4) also predicts the 2 state but requires low lying states of J = y and 1" which have not been identified. The 0" state can also be obtained by double nucleon excitation, e.g. in the configuration pfj p i - The transition probability of the O " state for pair emission to the ground state can be estimated from the cross section for excitation of this state with electrons. Schiff claims that the value obtained is too small to be explained by the alpha particle model and too large to be accounted for by a // coupling model with excitation of two -particles he suggests that a collective model intermediate in properties between the two extreme models is necessary. 

One of the special cases of coupled-cluster theory is the singles-and-doubles (CCSD) model [37]. The cluster operator Eq. (29) is restricted to contain only the singles and doubles excitation operators. The importance of this model can be seen from the fact that, for any coupled-cluster wave function, the singles and doubles amplitudes are the only ones that contribute directly to the coupled-cluster energy. In the explicitly correlated CCSD model the conventional cluster operator containing the T and T2 operators is supplemented with an additional term that takes care of the explicit correlation (written with red font)... 

A coupling model has also been developed by Kubat et al. (1999,2000). In it, the authors proposed that, while single relaxation events are most likely to occur, a cluster of these relaxations can also take place. Thus, in addition to single elementary transitions, double, triple, and higher transitions may occm with decreasing relaxation times (t,t/2, t/3,. ..). While the available firee volume still... 

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