Chemical isotropic

An interesting demonstration of profile control via alteration of the specific chemistry is that of silicon etching in C1F3 mixtures (86). Because a pure chemical (isotropic) etchant (F atoms) is combined with an ion-bombardment-controlled (anisotropic) etchant (Cl atoms), a continuous spectrum of profiles with varying anisotropies is generated by changing the gas composition. 

The rate constant calculation may be essentially simplified in comparison to standard recipe used in the encounter theory, basing on the fact that A/R is a small parameter according to the definition of the contact reactions. This way, having approved in chemically isotropic reactions in /14/, was spread on the reactions of anisotropic particles A and B /13,15/. It turned to be very efficient approximate way to calculate the rate constant, presented as... 

Closs G L and Trifunac A D 1970 Theory of chemically Induced nuclear spin polarization. III. Effect of Isotropic g shifts In the components of radical pairs with one hyperfine Interaction J. Am. Chem. Soc. 92 2183-4... 

Since chemical reactions are on a scale much below 1 Im, and it appears that the Komolgoroff scale of isotropic turbulence turns out to be somewhere between 10 and 30 Im, other mechanisms must play a role in getting materials in and out of reaction zones and reactants in and out of those zones. One cannot really assign a shear rate magnitude to the area around a micro-scale zone, ana it is primarily an environment that particles and reactants witness in this area. 

Chemical shift (isotropic component) 5. ISO Magic-angle spinning Chemical bonding coordination number... 

Nazem [31] has reported that mesophase pitch exhibits shear-thinning behavior at low shear rates and, essentially, Newtonian behavior at higher shear rates. Since isotropic pitch is Newtonian over a wide range of shear rates, one might postulate that the observed pseudoplasticity of mesophase is due to the alignment of liquid crystalline domains with increasing shear rate. Also, it has been reported that mesophase pitch can exhibit thixotropic behavior [32,33]. It is not clear, however, if this could be attributed to chemical changes within the pitch or, perhaps, to experimental factors. 

Predict the isotropic chemical shift for carbon in benzene with respect to TMS. 

At low rotation rates, less than the chemical shifts anisotropy, however, the powder spectra contained disturbing side bands dispersed among the isotropic chemical shifts. In order to discriminate between sidebands and isotropic resonances two spectra obtained at different spinning speeds were multiplied together or the differentiation was made by visual inspection. 

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