scholarly journals Visualization of temperature fields of transient natural convection with maximum density effect in a water-filled enclosure by chiral nematic liquid crystals.

1990 ◽  
Vol 23 (2) ◽  
pp. 241-244 ◽  
Author(s):  
Tatsuo Nishimura ◽  
Masaki Fujiwara ◽  
Hisashi Miyashita
Keyword(s):  
Natural Convection ◽  
Liquid Crystals ◽  
Nematic Liquid Crystals ◽  
Maximum Density ◽  
Density Effect ◽  
Temperature Fields ◽  
Transient Natural Convection ◽  
Chiral Nematic

Circularly polarized luminescence in chiral nematic liquid crystals: generation and amplification

2021 ◽  
Author(s):  
Xuefeng Yang ◽  
Xue Jin ◽  
Tonghan Zhao ◽  
Pengfei Duan
Keyword(s):  
Liquid Crystals ◽  
Nematic Liquid Crystals ◽  
Excellent Performance ◽  
Circularly Polarized ◽  
Chiral Nematic ◽  
Circularly Polarized Luminescence ◽  
Polarized Luminescence

Chiral nematic liquid crystals exhibit excellent performance in obtaining high luminescence dissymmetry factor of circularly polarized luminescence.

scholarly journals Nanocomposites of Polyaniline and Cellulose Nanocrystals Prepared in Lyotropic Chiral Nematic Liquid Crystals

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Dawei Zhang ◽  
Lihong Zhang ◽  
Bingzhe Wang ◽  
Guangzhe Piao
Keyword(s):  
Liquid Crystals ◽  
Cellulose Nanocrystals ◽  
Nematic Liquid Crystals ◽  
Weight Ratio ◽  
Asymmetric Reaction ◽  
Reaction Field ◽  
Electron Microscopies ◽  
Chiral Nematic ◽  
Before And After

Stable lyotropic chiral nematic liquid crystals (N*-LCs) of cellulose nanocrystals (CNs) were prepared via hydrolysis using sulfuric acid. The lyotropic N*-LCs were used as an asymmetric reaction field to synthesize polyaniline (PANI) onto CNs by in situ polymerization. As a primary step, we examined the mesophase transition of the N*-LCs of CNs suspension before and after in situ polymerization of aniline (ANI) by polarizing optical microscopy. The structure of nanocomposites of PANI/CNs was investigated at a microscopic level using Fourier transform infrared spectroscopy and X-ray diffraction. Influence of the CNs-to-ANI ratio on the morphology of the nanocomposites was also investigated at macroscopic level by scanning electron and transmission electron microscopies. It is found that the weight ratio of CNs to aniline in the suspension significantly influenced the size of the PANI particles and interaction between CNs and PANI. Moreover, electrical properties of the obtained PANI/CNs films were studied using standard four-probe technique. It is expected that the lyotropic N*-LCs of CNs might be available for an asymmetric reaction field to produce novel composites of conjugated materials.

New benchmark solutions for transient natural convection in partially porous annuli

2016 ◽  
Vol 26 (3/4) ◽  
pp. 1187-1225 ◽  
Author(s):  
Nicola Massarotti ◽  
Michela Ciccolella ◽  
Gino Cortellessa ◽  
Alessandro Mauro
Keyword(s):  
Natural Convection ◽  
Free Convection ◽  
Transient Flow ◽  
Flow Behavior ◽  
Outer Radius ◽  
Temperature Fields ◽  
Content Type ◽  
Transient Natural Convection ◽  
Velocity And Temperature Fields ◽  
Benchmark Solutions

Purpose – The purpose of this paper is to focus on the numerical analysis of transient free convection heat transfer in partially porous cylindrical domains. The authors analyze the dependence of velocity and temperature fields on the geometry, by analyzing transient flow behavior for different values of cavity aspect ratio and radii ratio; both inner and outer radius are assumed variable in order to not change the difference ro-ri. Moreover, several Darcy numbers have been considered. Design/methodology/approach – A dual time-stepping procedure based on the transient artificial compressibility version of the characteristic-based split algorithm has been adopted in order to solve the transient equations of the generalized model for heat and fluid flow through porous media. The present model has been validated against experimental data available in the scientific literature for two different problems, steady-state free convection in a porous annulus and transient natural convection in a porous cylinder, showing an excellent agreement. Findings – For vertically divided half porous cavities, with Rayleigh numbers equal to 3.4×106 for the 4:1 cavity and 3.4×105 for the 8:1 cavity, the numerical results show that transient oscillations tend to disappear in presence of cylindrical geometry, differently from what happens for rectangular one. The magnitude of this phenomenon increases with radii ratio; the porous layer also affects the stability of velocity and temperature fields, as oscillations tend to decrease in presence of a porous matrix with lower value of the Darcy number. Research limitations/implications – A proper analysis of partially porous annular cavities is fundamental for the correct estimation of Nusselt numbers, as the formulas provided for rectangular domains are not able to describe these problems. Practical implications – The proposed model represents a useful tool for the study of transient natural convection problems in porous and partially porous cylindrical and annular cavities, typical of many engineering applications. Moreover, a fully explicit scheme reduces the computational costs and ensures flexibility. Originality/value – This is the first time that a fully explicit finite element scheme is employed for the solution of transient natural convection in partially porous tall annular cavities.

Nematicons routing through two types of disclination lines in chiral nematic liquid crystals

2014 ◽  
Vol 23 (04) ◽  
pp. 1450042 ◽  
Author(s):  
Michał Kwaśny ◽  
Urszula A. Laudyn ◽  
Katarzyna A. Rutkowska ◽  
Mirosław A. Karpierz
Keyword(s):  
Liquid Crystals ◽  
Wave Vector ◽  
Nematic Liquid Crystals ◽  
Input Beam ◽  
Oriented Sample ◽  
Beam Position ◽  
Chiral Nematic ◽  
Different Types ◽  
Optimal Beam ◽  
Beam Parameters

In this work, we study nematicons propagation at the disclination lines in a wedge-shaped planarly oriented sample. Using optimal beam parameters for light self-trapping and varying the input beam position and direction of the wave vector k with respect to the z-axis, we gain insight in the nematicons propagation in the highly disturbed area around two different types of disclination lines in chiral nematic.

Chlorin e6 13(N)-methylamide-15,17-dimethyl ester and its nickel complex as the inducers of chiral nematic liquid crystals

2021 ◽  
pp. 118330
Author(s):  
V.A. Burmistrov ◽  
I.V. Novikov ◽  
V.V. Aleksandriiskii ◽  
D.V. Belykh ◽  
O.M. Startseva ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Nickel Complex ◽  
Nematic Liquid Crystals ◽  
Dimethyl Ester ◽  
Chlorin E6 ◽  
Chiral Nematic
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