SUMMARY: A dynamic Monte Carlo (MC) simulation is performed to investigate the phase behavior of mixtures of flexible polymers and low molecular weight thermotropic liquid crystals (LCs). The polymer is represented by three-dimensional self-avoiding lattice chains, while the LC is described by the LebwohlLasher nematogen model. The initially homogeneous rod-coil mixture is, following a deep quench, separated into an isotropic phase rich in coils and a nematic phase rich in rods. The underlying spinodal decomposition (SD) process is then simulated and studied extensively. This is the first simulation of SD in a rod-coil mixture where the nematic ordering is included. Concentration fluctuations with a conserved order parameter are thus coupled with orientation fluctuations with a nonconserved order parameter. It is found that the early stage SD in the rod-coil mixture still exhibits the dominant spatial wavelength and that the scalar scattering functions in the late stage of SD obey the Furukawa scaling law. The kinetic difference between the so-called isotropic and anisotropic SD regions is, however, much less pronounced than predicted recently by the mean-field theory.
The effect of depth-induced light extinction (DILE) is proposed and investigated both in theory and in experiment. This phenomenon may occur by adjusting the effective depth of an anisotropic entity observed orthoscopically in a polarizing microscope while maintaining the internal structure. The analytical interpretations are made in both monochromatic light and multichromatic light and reveal that the DILE effect is much more obvious in monochromatic light. The DILE in the radial nematic droplet as well as that in the normal-oriented axial one is then calculated and analysed in detail. The experimental observations are in satisfactory agreement with corresponding theoretical analyses and prove that the nematic droplets in the poly(methyl acrylate)-based polymer dispersed liquid crystal (PDLC) film have the radial director configuration. The advantage of DILE is that it can, by two-dimensional polarizing micrographs, reflect the third dimension parallel to the incident light. Some prospective applications of DILE are pointed out. Finally, extinction effects besides DILE are classified and discussed.
The problem of N three-level atoms interacting with two resonant cavity modes in an ideal cavity is considered. The spectral properties of the fluorescence field are discussed. It is shown that the sidebands of the fluorescence prove to be sources of the intense field ( -N 2 ) which has sub-Poissonian statistics. The squeezing of the spectrum components is also discussed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.