Dynamic precursor

Butler D A and Hayden B E 1995 The indirect channel to hydrogen dissociation on W(100)c(2 2)Cu—evidence for a dynamical precursor Chem. Phys. Lett. 232 542... 

The presence of a precursor breaks the dynamical motion into tliree parts [34], First, there is the dynamics of trapping into the precursor state secondly, there is (at least partial) thennalization in the precursor state and, thirdly, the reaction to produce the desired species (possibly a more tightly bound chemisorbed molecule). 

Butler D A, Hayden B E and Jones J D 1994 Precursor dynamics in dissociative hydrogen adsorption on W(100) Chem. Phys. Leff. 217 423... 

Rettner C T, Schweizer E K and Stein H 1990 Dynamics of chemisorption of N2 on W(100) Precursor-mediated and activated dissociation J. Chem. Phys. 93 1442... 

J Rettner C T and Mullins C B 1991 Dynamics of the chemisorption of O2 on Pt(111) Dissociation via direct population of a molecularly chemisorbed precursor at high incidence kinetic energy J. Chem. Phys. 94 1626... 

J.N. Johnson, O.E. Jones, and T.E. Michaels, Dislocation Dynamics and Single-Crystal Constitutive Relations Shock-Wave Propagation and Precursor Decay, J. Appl. Phys. 41, 2330-2339 (1970). 

When spontaneous spreading occurs, the bulk of the advancing liquid is preceded by a precursor film, usually a few millimeters in width and a few hundred nanometers or less in thickness [58], as pictured in Fig. 12. The observed dynamic contact angle is that which is made by the bulk liquid against the precursor film, and it itself depends on the rate of the advance of the nominal interline. The relationship between the rate of spontaneous spreading, i.e. the rate of movement of the nominal interline normal to itself, (/, and the dynamic contact... 

It should be realized that unlike the study of equilibrium thermodynamics for which a model is often mapped onto Ising system, elementary mechanism of atomic motion plays a deterministic role in the kinetic study. In an actual alloy system, diffusion of an atomic species is mainly driven by vacancy mechanism. The incorporation of the vacancy mechanism into PPM formalism, however, is not readily achieved, since the abundant freedom of microscopic path of atomic movement demands intractable number of variational parameters. The present study is, therefore, limited to a simple spin kinetics, known as Glauber dynamics [14] for which flipping events at fixed lattice points drive the phase transition. Hence, the present study for a spin system is regarded as a precursor to an alloy kinetics. The limitation of the model is critically examined and pointed out in the subsequent sections. 

Titanium imido complexes supported by amidinate ligands form an interesting and well-investigated class of early transition metal amidinato complexes. Metathetical reactions between the readily accessible titanium imide precursors Ti( = NR)Cl2(py)3 with lithium amidinates according to Scheme 84 afforded either terminal or bridging imido complexes depending on the steiic bulk of the amidinate anion. In solution, the mononuclear bis(pyridine) adducts exist in temperature-dependent, dynamic equilibrium with their mono(pyiidine) homologs and free pyridine. 

The vibrations of molecular bonds provide insight into bonding and stmcture. This information can be obtained by infrared spectroscopy (IRS), laser Raman spectroscopy, or electron energy loss spectroscopy (EELS). IRS and EELS have provided a wealth of data about the stmcture of catalysts and the bonding of adsorbates. IRS has also been used under reaction conditions to follow the dynamics of adsorbed reactants, intermediates, and products. Raman spectroscopy has provided exciting information about the precursors involved in the synthesis of catalysts and the stmcture of adsorbates present on catalyst and electrode surfaces. 

This paper presents the physical mechanism and the structure of a comprehensive dynamic Emulsion Polymerization Model (EPM). EPM combines the theory of coagulative nucleation of homogeneously nucleated precursors with detailed species material and energy balances to calculate the time evolution of the concentration, size, and colloidal characteristics of latex particles, the monomer conversions, the copolymer composition, and molecular weight in an emulsion system. The capabilities of EPM are demonstrated by comparisons of its predictions with experimental data from the literature covering styrene and styrene/methyl methacrylate polymerizations. EPM can successfully simulate continuous and batch reactors over a wide range of initiator and added surfactant concentrations. 

Number of k-fold Precursor Particles. Dynamic differential equations were written for the concentration of the k-fold precursors to account for birth and death by coagulation, growth by propagation, and the formation of primary precursors by homogeneous nucleation. There... 

While metabolic engineers traditionally sought the rate-limiting enzyme to unlock flow through a pathway, now they understand that there may be many points of control and feedback with the metabolic network, and seek to empirically determine the dynamics of the interactions between rate controllers and other factors. For example, the sizes of metabolic precursor pools and the catabolism or sequestration of products affect accumulation as well as flux through the pathway. 

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