System metastable

Actually, a total closed-loop phase lag limit of 3i5 degrees is commonly used by designers any closer to 360 degrees would constitute a metastable system. This could result in the power supply breaking out into periods of oscillation when large loads or line transients are experienced. 

For the collision dynamics, a semi-classical method is quite accurate for intermediate energies about 50 keV. Note the use of a more recent collision program using the propagation method for the N " (ls2s) + He metastable system. 

When mixed with 30% of oxygen it creates a metastable system, which is particularly dangerous if the temperature is greater than 80°C. 

It is worth noting that a monotropic polymorphic system offers the potential of annealing the substance to achieve the preferred form of the thermodynamically stable phase. The use of the most stable form is ordinarily preferred to avoid the inexorable tendency of a metastable system to move toward the thermodynamic form. This is especially important especially if someone elects to use a metastable phase of an excipient as part of a tablet coating, since physical changes in the properties of the coating can take place after it has been made. Use of the most stable form avoids any solid-solid transition that could... 

K. Kristiakova, K., Svec, P. (2001) Continuous distribution of thermodynamic microprocesses in complex metastable systems, Phys. Rev. B 64,184202. 

The application of solid compounds with cluster units as sources for new molecular compounds, as well as for new polymers opens up an attractive field in chemistry. In view of the wealth of binary and ternary solid compounds, there is no end in sight. The wide range of materials should encourage many chemical groups to work much more in this direction. Especially fascinating is the possibility to form new modifications of the elements which as metastable systems could also have interesting chemical and physical properties. 

The data required for method II are the measurable quantities AGf°[ij] and, if Kn is not 0, AHmn, Tmn, and Cps[n] and an extrapolated quantity Cp[n], To make use of available data, the standard Gibbs energy of formation can be expressed in terms of the standard enthalpy and entropy of formation. The advantage of this formulation is that thermodynamic information for unstable or metastable systems is required only for the elements (i.e., Cp[n]), for which a better estimate can usually be made. This data base contains no explicit liquid-solution properties. 

In view of the instability at room temperature, Hoch and Johnston288 investigated SiO in the solid phase at 1300 °C and found by X-ray analysis a new lattice, a cubic cell with a = 7.135 A, which they postulated to be the SiO lattice. Decomposition occurs when the product is cooled slowly and the X-ray lines of silicon and Si02 may be seen below 850 °C. With rapid cooling, e.g. from 1300 °C to 850 °C over 2 minutes, the SiO lattice is frozen as a metastable system. 

A system may be in a stable, metastable, unstable, or neutral equilibrium state. In a stable system, a perturbation causes small departures from the original conditions, which are restorable. In an unstable equilibrium, even a small perturbation causes large irreversible changes. A metastable system may be stable or unstable according to the level and direction of perturbation. All thermodynamic equilibria are stable or metastable, but not unstable. This means that all natural processes evolve toward an equilibrium state, which is a global attractor. 

In Figure 2F-1 the composition where d2( G)/d 22 s equal to zero, or at the inflection point on the Gibbs energy surface, is defined as the spinodal composition. This corresponds to the boundary between an unstable solution and a metastable solution. If the necessary amount of free energy is supplied to the metastable system, the solution will phase separate into two phases with binodal compositions unstable system will always phase separate into the two phases. The temperature where the two points of inflection on the energy surface merge into a single point is defined as the critical solution temperature. 

Figure 4 The Fe-Fe3C metastable system imderlying the carbon steel making technology. (Ref. 28. Reproduced by permission of McGraw-HiU)...

The interaction of LiOEEM (30) with a dimeric model of living PtBMA was studied in THF at low temperature by NMR techniques. A metastable system was observed that needed several days at —15 °C to reach equilibrium. LiOEEM is prone to self-association, which competes with formation of mixed aggregates with the dimeric model. When the LiOEEM/dimeric model molar ratio is low (up to 4), the aggregation is incomplete and several complexes coexist ... 

In equation (29) the symbol hv denotes the energy of a quantum of light of frequency v. The notation signifies that when the H2-CI2 mixture is irradiated by light of an appropriate frequency, light quanta are absorbed by chlorine molecules, causing them to dissociate. Any process of this kind, where radiation induces a reaction in an otherwise metastable system, is termed photosensitization. There are also many examples of processes in which reaction intermediaries or products are formed in excited states and deactivate by emitting nonthermal radiation this phenomenon is called... 

H. Levine and L. Slade, Thermomechanical properties of small-carbohydrate-water glasses and rubbers, kinetically metastable systems at sub-zero temperatures. J. Chem. Soc. Faraday Trans. 1, 84, 8, 2619—2633, 1988. 

In the same context, the metal sulfide substrate is a component of an Me-S-HjO system which may be far from equilibrium and which may contain a number of metastable molecular and ionic species. While the availability of the relevant thermodynamic data, especially for metastable systems, is far from complete, Eh-pH diagrams have been constructed in connection with... 

I. Horenko, E. Dittmer, F. Lankas, J. Maddocks, P. Metzner, and C. Schiitte (2005) Macroscopic dynamics of complex metastable systems Theory, algorithms, and application to b-dna. J. Appl. Dyn. Syst, submitted... 

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