Anchoring phase substrate dependence

Most of the aforementioned methods use gas-phase feedstock, including CVD via the VLS mechanism in the presence of metal catalysts, evaporation at high temperatures without the use of metal catalysts, or laser vaporization in the presence of metal catalysts. Solution-liquid-solid methods have been explored in the presence of metal catalysts and under supercritical conditions. These two mechanisms can result in either tip or root growth, meaning that the catalysts can be either suspended in space at the tips of the growing nanowires, or anchored at the surface of the substrate, depending on the strength of interactions between the nanoparticles and the substrate. 

STM stttdies of anchoring phase transitions at nematic interfaces E SUBSTRATE DEPENDENCE M0S2 AND GRAPHITE (HOPG)... 

Fig. 2 Sketch of liquid crystal confined in the gap between a modified microsphere and a glass substrate (not to scale). Dependent on the anchoring strength, liquid crystal and temperature the substrate induces prenematic or/and presmectic alignment. If both surfaces approach each other, isotropic liquid crystal condenses into a nematic phase in the gap between both surfaces, causing attraction...

The term surface means here the surface of the other phase in contact with the nematic liquid crystal. The symmetry of this surface (and of 7s) is independent of the orientation taken by the nematic phase at the surface. In contrast, the symmetry of the interface depends on this orientation it is the subgroup of the surface symmetry group containing the symmetry elements which leave invariant the anchoring direction effectively taken by the liquid crystal. If the other phase is a solid or liquid substrate, the surface is simply the surface of this substrate. In the case when the other phase is the gas or isotropic phase, the surface is not a physical entity. However, one can still, in principle, distinguish this isotropic surface (C symmetry) from the interface with the nematic phase, the symmetry of which is C , Cjv, and Cjj, for homeotropic, planar, and tilted anchoring, respectively. 

The properties of stationary structures of enzymatic processes can be different from those obtained in gas phase calculations because, obviously, the interaction with the environment are not considered in the latter. Then, a more realistic picture of enzyme catalyzed reactions can be obtained including a small part of the active centre into the calculations. The problem is that in this cluster or supermolecule models, the optimised stmetures do not necessary fit into the enzyme active site and computing artefacts can be obtained. A common strategy is to anchor some key atoms of the enzyme to their crystallographic positions and then optimize the rest of the coordinates of the model [39]. Nevertheless, this is an approximate solution that presents several deficiencies. First, the result will be dependent on the initial X-ray stmeture that, in many cases, is far from the real stmeture of the protein-substrate complex at the TS. Second, long-range effects on the nuclear and electronic polarisation of the chemical system are not included in the calculations. Third, and probably the most dramatic deficiency, the enzyme flexibility is not properly taken into account. And finally, the computational cost of these calculations rapidly increases, as more atoms of the environment are explicidy included. 

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