States quasi-stable

Stage II is the quasi-steady-state nucleation regime. During this period, the distribution of clusters has built up into a quasi-steady state and stable nuclei are being produced at a constant rate. 

ENERGY LEVEL. A stationary state of energy of any physical system. The existence of many stable, or quasi-stable, slates, in which the energy of the system stays constant for some reasonable length of time, is an essential characteristic of quantum-mechanical systems, and is the basis of large areas of modem physics. 

Thus the isometric case starts with the A-M.D.Pj state and the lower 50K cleft bound to actin. Closure of the cleft is fast and results in a distortion of the /(-sheet of the upper 50K domain. This tends to destabilize the P-loop, leading to Pj release, but, if the movement of the lever-arm and converter is not complete, then the whole process is not completed and at mM P concentration P, can rebind, leading to the loss of force and detachment. When the crossbridge is held isometric, all steps in Scheme S are in a quasi-stable dynamic equilibrium. 

Fig. 5.7. Variation of quasi-steady-state temperature excess O s with the dimensionless reactant concentration for the Salnikov model. The steady-state is stable at high and low fi but is unstable over a region fi < fi < fi indicated by the broken section of the locus.

Although the type of mineral that ultimately forms is mainly governed by its thermodynamic stability, what is observed at any time or even as a quasi-stable end product, is governed by kinetic factors. Important parameters that govern the phase that forms are temperature solution composition (pH Eh Fe concentration and oxidation state type and concentration of anions) rate of Fe supply rate of oxidation. 

A quasi-stationary state is stable if a small excursion from it is self-correcting, but is unstable if the excursion escalates. Specifically, in a system as described here, stability is ensured if the net rates rx and rY decrease if the concentrations of X and Y increase. If this is true for one of the intermediates, but not for the other, the stabilizing and destabilizing tendencies counteract one another, and the (necessary and sufficient) condition for stability becomes... 

As we have discussed earlier, because of the presence of the HB network structure water has an enormous number of stable or quasi-stable energy states (reflected in its high heat capacity). This is also reflected in the difficulty of ice formation in computer simulations. The system needs to search for a long time to find the global minimum for ice structure. The system explores the potential-energy landscape for a considerable amount of time before the start of the ice formation. This scenario agrees well with the nucleation picture discussed earlier in this chapter. 

DiolOCtriC Thoory. The piezoelectricity in amorphous polymers differs from that in semicrystalline polymers and inorganic crystals in that the polarization is not in a state of thermal equilibrium, but rather a quasi-stable state because of the freezing-in of molecular dipoles. The result is a piezoelectric-hke effect. A theoretical model for polymers that have frozen-in dipolar orientation was presented to explain piezoelectricity and p5Toelectricity in amorphous polymers such as poly(vinyl chloride) (39). 

The cyclic voltammograms shown in Figure 3.3 illustrate that, even for monocrysfalline sfructures, multiple states are represented by many peaks in the curve. This means that there are multiple states below a monolayer with quasi-stable surface organization or by partial charge transfer from the anion [2,22]. 

The piezoelectricity in amorphous polymers differs from that in semi-crystalline polymers and inorganic crystals in that the polarization is not in a state of thermal equilibrium, but rather a quasi-stable state due to the ffeezing-in of molecular dipoles. As mentioned by Broadhurst and Davis (55), four criteria are essential to make an amorphous polymer exhibit piezoelectric behavior. First, molecular dipoles must be present. As seen in Table 1, these dipoles are typically pendant to the polymer backbone as are the nitrile groups in PAN, PVDCN-VAC, and (p-CN) APB/ODPA. However, the dipoles may also reside within the main chain of the polymer such as the anhydride units in the (P-CN) APB/ODPA polyimide. In addition to a dipole moment X, the dipole concentration N (number of dipoles per unit volume) is also important in determining the ultimate polarization, P , of a polymer. 

In addition to these stable state quasi crystals, there are much more binary and ternary alloys that form metastable quasi crystalline states. 

The linear stability analysis with respect to homogeneous perturbations at the surface, shows that the scale thickness is a bifurcation parameter. Thus the quasi stationary state is stable up to a bifurcation point resulting from the destabilizing effects of the interfacial processes beyond a certain thickness the quasi stationary regime becomes stable again because of the stabilizing effects of the bulk diffusion. 

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