Crystallization composites

The crystal compositions vary, depending on the transport agent used, from TiB,4,y (Ij) and TiBj <,4 (TeCl4). At process temperatures > 1000°C and with I2, the transport direction is reversed. Crystals grow in the cold zone of the tube, but only microscopic needle-like crystals are obtained. ... 

All of these factors are dependent upon the nature of the crystal composition being grown including its themicil, physical and chemical properties. Because of the importance of R.F. generators to crjrstal growth, let us now examine them in more detcill. 

Wood and Blundy (1997) adapted the lattice strain model to describe lanthanide partitioning between clinopyroxene and melt as a function of crystal composition, pressure and temperature. In developing the model, they arrived at relationships between and respectively, crystal composition, and pressure and temperature ... 

Landwehr et al. (2001) extended the model of Wood and Blundy (1997) to include and Th". They measured experimentally Aj and Z)xh in a wide variety of synthetic clinopyroxene compositions in order to evaluate the crystal compositional dependence of U-Th fractionation. Their observations confirm the predictions of Wood et al. (1999), namely that as the M2 site becomes smaller, so D-m becomes smaller than Du (Figs. 1 and 11). The M2 site becomes smaller as the enstatite component of the clinopyroxene increases and Ca on M2 is replaced by Mg. Enstatite solubility in clinopyroxene increases with increasing temperature, consequently clinopyroxene coexisting with orthopyroxene will show higher Du/Dih at higher temperature. For this reason, DuIDjb increases with increasing pressure along the mantle solidus, as discussed above. 

Having successfully described the variation in DulDj with crystal composition, pressure and temperature, Landwehr et al. (2001) went on to parameterize U-m from their own and published studies in terms of a simple partitioning equilibrium ... 

Uranium and thorium partitioning into amphibole were also studied experimentally by Tiepolo et al. (2000a). Under the redox conditions of their experiments (FMQ-2 log units) U was dominantly tetravalent. They find no correlation between Aj, Djh and crystal composition, and, but again find a linear correlation with silica content ... 

Insensitive Energetic Materials - Particles, Crystals, Composites, Eds. Teipel, U., Herrmann, M., (Symposium Proceeding), Fraunhofer IRB Verlag, 2007, Stuttgart, Germany, ISBN 978-3-8167-7328-3 Organic Chemistry of Explosives... 

Murray, J. W, Garman, E. and RavelU, R. (2004). X-ray absorption by macromolecular crystals the effects of wavelength and crystal composition on absorbed dose. /. Appl. Crystallogr. 37, 513-522. 

If the interface reaction rate is extremely small so that mass/heat transfer is rapid enough to transport nutrients to the interface, then interface reaction rate (Equation 4-33) is the overall heterogeneous reaction rate (Figure 1-lla). If the interface reaction is relatively rapid and if the crystal composition is different from the melt composition, the heterogeneous reaction rate may be limited or slowed down by the mass transfer rate because nutrients must be transported to the interface and extra junk must be transported away from the interface (Figures 1-llb and 1-llc). If the crystal composition is the same as the melt composition, then mass transfer is not necessary. When interface reaction rate and mass transfer rate are comparable, both interface reaction and mass transfer would control the overall heterogeneous reaction (Figure 1-lld). 

For crystal growth at constant rate, if the crystal composition can respond to interface melt composition through surface equilibrium, steady state may be reached (Smith et ah, 1956). At steady state, (dCldt) = 0 by definition. Hence,... 

Give initial conditions, including (i) the melt composition, density, diffusivity, and viscosity, (ii) crystal composition and density,... 

Application of the rod-like 3,6-disubstituted-l,2-dithiins in liquid crystal compositions and also as antifugal agents and anti-infectives was reported in the patent literature. 

Wronkiewicz, D. L., Wolf, S. F. DiSanto, T. S. 1996. Apatite- and monazite-bearing glass-crystal composites for the immobilization of low-level nuclear and hazardous wastes. Materials Research Society Symposium Proceedings, 412, 345-352. 

Title Polymerizable Liquid-Crystal Composition and Uses for the Same... 

Goldfinger (4) proposed preparing an alkoxy(meth)acrylate cholesterol derivative, (III), as a liquid-crystal composition. 

Title Liquid-Crystal Compositions and Polymer Networks Derived Therefrom... 

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