Optical Study Of Polymer Dispersed Mixed Liquid Crystals
Recently, Liquid Crystal (LC) dispersed with polymer is used to enhance the physical properties of the LCs materials. These materials possess combined application of LC and polymer and their electro-optic applications have been extensively studied during last decades. The LC mixture consists of Nematic and Cholestric that are dispersed in a monomer or prepolymer with different concentration. The existing Polymer Dispersed Liquid Crystal (PDLC) consists of different concentrations of LC and monomer. The textures and Phase transition temperature (PTTs) can be studied by Polarising Microscope Studies (PMS). The Phase transition temperature (PTTs) can also be studied by Fabry-Perot etalon Scattering Studies (FPSS) In this paper, we present the changes in transition temperature along with new phase transition temperature in PDLC. Measurements were performed for both heating and cooling of various samples. In addition to this, Refractive Index (RI) of all samples were found for optical characterization of the material. Texture observation and spectroscopic techniques are used to characterize the other properties of the PDLC samples. The PDLC suspension can be used as a new liquid crystalline material that does not require any additional alignment processing or treatment. Our results will provide new opportunity and their uses in advanced technology development.
Effect of Light on Nematic Liquid Crystal
Liquid Crystal is a phase formed between a crystal and a liquid with a degree of order intermediate between the molecular disorder of liquid and the regular structure of crystal..The optical properties of Liquid Crystals are one of the most interesting and certainly the most beautiful features of the phase. In this paper we studied the properties of light as it propagates through a sample of Nematic Liquid Crystals. Amongst various properties of light; we studied polarization and scattering of light through Nematic Liquid Crystals. Liquid crystal materials generally have several common characteristics. One of the characteristics is the transition temperature which will be measured over temperature range of phases. In present work we studied Cholesteryl Oleate. The results are analyzed with the help Polarizing microscopy (PMS) and Spectroscopic technique using Fabery —Perot Etalon. The phase transition of liquid crystal between various mesomorphic forms occurs at a thermodynamically defined temperature as ...
Anomalous Annealing Behavior of Arsenic Implanted Silicon as a Function of Dose and Energy
Anomalous annealing behavior of damage in As implanted Si has been investigated by channeling effect measurements. Room temperature As implants with doses from 1014 to 2 × 1016cm-2 at energies ranging from 50 to 250 keV into Si were annealed over the range of 600°C to 1100°C. Anneal temperatures ≥ 950°C reduce the disorder for ion doses of 0.5 to 1 × 1016 cm-2 at energies between 50 and 250 keV. Anomalously high residual disorder was found for the intermediate doses of 2 × 1014 to 2 × 10/cm2 implanted above 100 keV. For this intermediate dose, annealing of implants performed at liquid nitrogen temperatures did not show significant reduction in this damage. However implants at 200° to 300°C indicate a lower amount of damage compared to the room temperature implants.