Orientational ordering mixtures

Short-time Brownian motion was simulated and compared with experiments [108]. The structural evolution and dynamics [109] and the translational and bond-orientational order [110] were simulated with Brownian dynamics (BD) for dense binary colloidal mixtures. The short-time dynamics was investigated through the velocity autocorrelation function [111] and an algebraic decay of velocity fluctuation in a confined liquid was found [112]. Dissipative particle dynamics [113] is an attempt to bridge the gap between atomistic and mesoscopic simulation. Colloidal adsorption was simulated with BD [114]. The hydrodynamic forces, usually friction forces, are found to be able to enhance the self-diffusion of colloidal particles [115]. A novel MC approach to the dynamics of fluids was proposed in Ref. 116. Spinodal decomposition [117] in binary fluids was simulated. BD simulations for hard spherocylinders in the isotropic [118] and in the nematic phase [119] were done. A two-site Yukawa system [120] was studied with... 

Natural biological membranes consist of lipid bilayers, which typically comprise a complex mixture of phospholipids and sterol, along with embedded or surface associated proteins. The sterol cholesterol is an important component of animal cell membranes, which may consist of up to 50 mol% cholesterol. As cholesterol can significantly modify the bilayer physical properties, such as acyl-chain orientational order, model membranes containing cholesterol have been studied extensively. Spectroscopic and diffraction experiments reveal that cholesterol in a lipid-crystalline bilayer increases the orientational order of the lipid acyl-chains without substantially restricting the mobility of the lipid molecules. Cholesterol thickens a liquid-crystalline bilayer and increases the packing density of lipid acyl-chains in the plane of the bilayer in a way that has been referred to as a condensing effect. 

PNP. We suggest that with the TBP present on the dodecane side of the interface, the preferential orientation of the TBP PNP complex will be opposite to that for uncomplexed PNP. For a mixture of complexed and uncomplexed PNP this will result in an overall reduction in the overall net orientation, that is, a reduction in the orientational order and a consequent reduction in the SHG intensity. This situation provides an explanation for a reduction in SHG intensity even when there is an increasing surface concentration of the PNP. 

Earlier versions (12-13,22) of this new mixture theory have predicted and reproduced experimental trends in various thermodynamic and molecular ordering properties [such as phase transition temperatures, phase stabilities (including of the N LC phase and the I liquid phase), curvatures of lines of coexisting phases, and orientational order P2] in binary mixtures as a function of T, P, system composition, and molecule chemical structures. 

The average Ifee-energy density of the NP-LC mixture is expressed in terms of the spatially averaged orientational order parameters S c and Sjqp of the mixture components LC and NP as... 

In order to clarify whether the presence of meta-oriented units would change the rate of oxadiazole methylation and thus would change the ultimate oxadiazole/hydrazide ratio in the fiber, identical polymerizations of all-para- and 50/50 para/meta-oriented monomer mixtures were sampled at various intervals, the polymer dope samples were coagulated and hydrolyzed in dioxane/ water and the polymer compositions determined. As data in Table III show, essentially identical oxadiazole/N-methyl hydrazide ratios were obtained for the all-para and the mixed para/meta compositions. 

Fig. 6.1.3. Quadrupole splittings for the aromatic and a-aliphatic vj deuterons of deuterated hexa-n-hexyloxytriphenylene (THE6) as functions of temperature (r— 7 ) in the mesophase region, where 7 is the mesophase-isotropic transition point. The open circles correspond to measurements on neat THE6-ard, and THE6-adi2 separately, while the filled circles correspond to a 2 1 mixture of the two isotopic species. The scale on the upper right-hand side gives the orientational order parameter of the aromatic part. The curve at the bottom gives the ratio of the quadrupole splittings for the a-aliphatic and aromatic deuterons (Goldfarb, Luz...

---