Dynamics, polyhedral

King RB (2005) Polyhedral dynamics and the Jahn-Teller effect. In Gielen M, Willem R, Wrackmeyer B (eds) Eluxional organometallic and coordination compounds. Wiley, New York, pp 1-37... 

Stephenson A, Argent SP, Riis-Johannessen T, Tidmarsh IS, Ward MD (2011) Structures and dynamic behaviour of large polyhedral coordination cages an unusual cage-to-cage interconversion. J Am Chem Soc. doi 10.1021/jal07403p... 

A study of the flow of a polyhedral foam in a regime of slip at the tube walls has been conducted [39]. It has been established that the rise in the dynamic viscosity of the foaming solution leads to diminishing the flow rate but to a much lesser extent at t0 = 1.25 Pa. Thus, a two fold increase in viscosity causes a 1.3 times decrease in the flow rate, while a 6 times increase in the dynamic viscosity only a 2.23 times decrease. This is probably related to the expanding of the effective thickness of the liquid layer 8 (ca. 3 times). The transition from plug flow (slip regime) to shear flow occurs at To = 9-10 Pa. This value of the shear stress is much smaller than the one obtained from Princen s formula for a two-dimensional foam (Eq. (8.18)) at a given expansion ratio and correlates well with To calculated from Eq. (8.24) and the experimental data of Thondavald and Lemlich [23],... 

Infrared light is absorbed through vibrations of the atoms or rotations of the molecular system. IR spectra give information on lattice dynamics, bond strengths, coordination, and polyhedral linkage in complex structures. 

Foam is a disperse system in which the dispersed phase is a gas (most commonly air) and the dispersion medium is a liquid (for aqueous foams, it is water). Foam structure and foam properties have been a subject of a number of comprehensive reviews [6, 17, 18]. From the viewpoint of practical applications, aqueous foams can be, provisionally, divided into two big classes dynamic (bubble) foams which are stable only when gas is constantly being dispersed in the liquid 2) medium and high-expansion foams capable of maintaining the volume during several hours or even days. In general, the basic surface science rules are established in foam models foam films, monodisperse foams in which the dispersed phase is in the form of spheres (bubble foams) or polyhedral (high-expansion foams). Meanwhile, real foams are considerably different from these models. First of all, the main foam structure parameters (dispersity, expansion, foam film thickness, pressure in the Plateau-Gibbs boarders) depend... 

Foam structure and dynamics. Surface layers surrounding the bubbles in a foam act as a membrane or skin that can stretch and relax in response to the lateral forces acting on it. At first, drainage of liquid taking place at the surface layer is entirely hydrod)niamic, but once spherical bubbles are in contact, flat walls develop between them, and polyhedral cells appear in the foam (Fig. 14.9c). Capillary forces be-... 

One of the first studies of PNC physical aging was published by Lee andLichtenhan [1998] for epoxy containing w = 0 to 9wt% of polyhedral oligomeric silsesquiox-ane (POSS). The presence of POSS increased Tg and the relaxation time thus, the nanoflller slowed down the molecular dynamics. For amorphous polymers at Tpstructural cluster model. The cluster volume fraction depends on temperature ... 

Kingma, K., Meade, C., Hemley, R.J., Mao, H.-H., and Veblen, D.R. (1993) Mi-crostructural observations of a-quartz amorphization. Science, 259, 666-669. Chaplot, S.L., and Sikka, S.K. (1993) Molecular-dynamics simulation of pressure induced crystalline-to-amorphous transition in some corner-linked polyhedral compounds, Phys. Rev., B47, 5710-5715. 

Yani, Y., and Lamm, M. H. 2009. Molecular dynamics simulation of mixed matrix nanocomposites containing polyimide and polyhedral oligometric silsesquiox-ane (ROSS). Polymer 50 1324-1332. 

The role of polyhedra in the static description of chemical structures, including those of coordination compounds, makes the dynamic properties of polyhedra also of considerable interest. The central concept in the study of dynamic properties of polyhedra is that of a polyhedral isomerization, which may be defined as the deformation of a specific polyhedron lIi until the vertices define a new polyhedron II2. Of particular interest are sequences of two polyhedral isomerization steps Hi 112 113 in which the polyhedron II3 is equivalent to the polyhedron Hi but with some permutation of the vertices. Such a polyhedral isomerization process is called a degenerate polyhedral isomerization with II2 as the intermediate polyhedron. A degenerate polyhedral isomerization in which the intermediate II2 is a planar polygon may be called a planar polyhedral isomerization. 

Another important area of research in biocompatible SMPINCs is the use of polyhedral oligomeric silsesquioxanes (POSS). In recent studies, these POSS cages primarily served as anchor sites for PCL chains to make organosilica SMPINCs with a wide variety of properties, ranging from triple-shape POSS/PCL networks [116], dynamic microscale surface features [117], ultrasoft networks post-transition... 

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