Model coherent

For both time-dependent and steady-state models, coherent dephasing is taken into account by phenomenological terms in the off diagonal time derivatives of the DM elements that appear in the Liouville dynamics. In the time dependent model, increasing the donor or bridge decoherences decreases the yield asymmetry and... 

The integration of object concepts is attractive to describe static and structural aspects. Classes generate entities that encapsulate both attributes (such as continuous variables) and methods which handle these data (including equations). In PrODHyS, objects are introduced in Petri net as well as Petri nets are introduced inside objects (figure 3). Tokens are typed and carry various kind of objects. Individualization and definition of classes for tokens make the model more compact without information loss. Hence, an ODPTPN is also characterized by typed arcs (that ensure model coherence) and transitions with conditions (expression with attributes and methods of allowed tokens) and actions (instanciate or destroy tokens, execute allowed token methods). 

As for the possibility of obtaining the same results in the same time without the support of the model, the interviewees provided different answers. In the majority of the cases, the interviewees reported that they would not obtain the same results in the same time without the support of the model (company 3, 5, 7, 8, and 9) in other cases, the interviewees were not able to answer to the question (company 1 and 4), and in other cases (company 2 and 10) the interviewees reported that they would obtain the same results in the same time without the support of the model, coherently with previous answers. 

Al.6.101) are precisely equivalent to these derivatives the rate of change of a population is proportional to the instantaneous coherence, a relationship which can be observed already in the vector precession model of the two-level system ( section Al.6.2.3). 

Depending on the relative phase difference between these temis, one may observe various experimental spectra, as illustrated in figure Bl.5.14. This type of behaviour, while potentially a source of confiision, is familiar for other types of nonlinear spectroscopy, such as CARS (coherent anti-Stokes Raman scattering) [30. 31] and can be readily incorporated mto modelling of measured spectral features. 

Polarons of Molecular Crystal Model by Nonlocal Dynamical Coherent Potential Method... 

In this section we shall consider in some detail the mechanism of coherence breakdown due to the bath, in order to clarify the physical assumptions which underlie the concept of rate constant at low temperatures. The particular tunneling model we choose is the two-level system (TLS) with the Hamiltonian... 

The simplest scheme that accounts for the destruction of phase coherence is the so-called stochastic interruption model [Nikitin and Korst 1965 Simonius 1978 Silbey and Harris 1989]. Suppose the process of free tunneling is interrupted by a sequence of collisions separated by time periods vo = to do After each collision the system forgets its initial phase, i.e., the off-diagonal matrix elements of the density matrix p go to zero, resulting in the density matrix p ... 

Today s high technology products and growing international competition require knowledgeable design decisions based on realistic models that include manufacturability requirements. A suitable and coherent tolerance allocation methodology... 

The schematic model is depicted in Fig. 8. As the bias voltage increases, the number of the molecular orbitals available for conduction also increases (Fig. 8) and it results in the step-wise increase in the current. It was also found that the conductance peak plotted vs. the bias voltage decreases and broadens with increasing temperature to ca. 1 K. This fact supports the idea that transport of carriers from one electrode to another can take place through one molecular orbital delocalising over whole length of the CNT, or at least the distance between two electrodes (140 nm). In other words, individual CNTs work as coherent quantum wires. 

For amide enolates (X = NR2), with Z geometry, model transition state D is intrinsically favored, but, again, large X substituents favor the formation of nt/-adducts via C. Factors that influence the diastereoselectivity include the solvent, the enolate counterion and the substituent pattern of enolate and enonc. In some cases either syn- or unh-products are obtained preferentially by varying the nature of the solvent, donor atom (enolate versus thioeno-late), or counterion. Most Michael additions listed in this section have not been examined systematically in terms of diastereoselectivity and coherent transition stale models are currently not available. Similar models to those shown in A-D can be used, however all the previously mentioned factors (among others) may be critical to the stereochemical outcome of the reaction. 

The above rate equations were originally largely developed from studies of gas—solid reactions and assume that particles of the solid reactant are completely covered by a coherent layer of product. Various applications of these models to kinetic studies of solid—solid interactions have been given. 

Komatsu [478] has put forward the hypothesis that reaction in many powder mixtures is initiated only at interparticle contact and that product formation occurs by diffusion through these contact zones. Here, one of the participating reactants is not covered with a coherent product layer. Quantitative consideration of this model leads to a modified Jander equation. 

If the molecule moves without hindrance in a rigid-walled enclosure (the free enclosure ), as assumed in free volume theories, then rattling back and forth is a free vibration, which could be considered as coherent in such a cell. The transfer time between opposite sides of the cell t0 is roughly the inverse frequency of the vibration. The maximum in the free-path distribution was found theoretically in many cells of different shape [74]. In model distribution (1.121) it appears at a > 2 and shifts to t0 at a - oo (Fig. 1.18). At y — 1 coherent vibration in a cell turns into translational velocity oscillation as well as a molecular libration (Fig. 1.19). 

Temkin S. I., Suvemev A. A. Evaluation of the CARS spectra of linear molecules in the Keilson-Storer model, In Coherent Raman Spectroscopy. ed. G. Marowsky, V. V. Smirnov, Springer Proceedings in Physics 63, pp. 49-53 (Springer, Berlin) (1992). 

Two types of observations show that our model of a gas must be refined. The qualitative observation is that gases can be condensed to liquids when cooled or compressed. This property strongly suggests that, contrary to the assumptions of the kinetic model, gas molecules do attract one another because otherwise they would not cohere (stick together). In addition, liquids are very difficult to compress. This... 

The capacity to construct a representation for a given purpose This was shown. Concrete (material) models were initially used, becoming progressively more sophisticated as the sequence of classes went on. Visual representations (diagrams) were readily employed. Most interestingly, symbolic representations were introduced and coherently used by the students despite the fact that they had not been systematically introduced to the conventions involved. 

Towards a Coherent Model for Macro, Submicro and Symbolic Representations in Chemical Education... 

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