Distorted Arene Core Allows Room-Temperature Columnar Liquid-Crystal Glass with Minimal Side Chains

2012 ◽  
Vol 51 (21) ◽  
pp. 5200-5203 ◽  
Author(s):  
Julien Kelber ◽  
Marie-France Achard ◽  
Fabien Durola ◽  
Harald Bock
Keyword(s):  
Liquid Crystal ◽  
Room Temperature ◽  
Crystal Glass ◽  
Side Chains

Distorted Arene Core Allows Room-Temperature Columnar Liquid-Crystal Glass with Minimal Side Chains

2012 ◽  
Vol 124 (21) ◽  
pp. 5290-5293 ◽  
Author(s):  
Julien Kelber ◽  
Marie-France Achard ◽  
Fabien Durola ◽  
Harald Bock
Keyword(s):  
Liquid Crystal ◽  
Room Temperature ◽  
Crystal Glass ◽  
Side Chains

Cholesteric liquid crystal glass platinum acetylides

2014 ◽  
Vol 1698 ◽  
Author(s):  
Thomas M. Cooper ◽  
Aaron R. Burke ◽  
Douglas M. Krein ◽  
Ronald F. Ziolo ◽  
Eduardo Arias ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Optical Materials ◽  
Liquid Crystalline ◽  
Room Temperature ◽  
Cholesteric Liquid Crystal ◽  
Isotropic Phase ◽  
Crystal Glass ◽  
Cholesteric Phase ◽  
Long Time ◽  
Cholesteric Liquid Crystalline

ABSTRACTTo prepare cholesteric liquid crystalline nonlinear optical materials with ability to be vitrified on cooling and form long time stability cholesteric glasses at room temperature, a series of platinum acetylide complexes modified with cholesterol has been synthesized. The materials synthesized have the formula trans-Pt(PR3)(cholesterol (3 or 4)-ethynyl benzoate)(1-ethynyl-4-X-benzene), where R = Et, Bu or Oct and X = H, F, OCH3 and CN. A cholesteric liquid crystal phase was observed in the complexes R = Et, and X = F, OCH3 and CN but not in any of the other complexes. When X = CN, a cholesteric glass was observed at room temperature which remained stable up to 130 °C, then converted to a mixed crystalline/cholesteric phase and completely melted to an isotropic phase at 230 °C. When X = F or OCH3 the complexes were crystalline at room temperature with conversion to the cholesteric phase upon heating to 190 and 230 °C, respectively. In the series X = CN, OCH3 and F, the cholesteric pitch was determined to be 1.7, 3.4 and 9.0 µ, respectively.

Infrared spectra of N-acetyl-L-α-amino-acid N'-methylamides with aliphatic side chains in non-polar solvents

1981 ◽  
Vol 46 (3) ◽  
pp. 772-780 ◽  
Author(s):  
Jorga Smolíková ◽  
Jan Pospíšek ◽  
Karel Bláha
Keyword(s):  
Amino Acid ◽  
Conformational Changes ◽  
Infrared Spectra ◽  
Room Temperature ◽  
Side Chains ◽  
Polar Solvents

Infrared spectra of the L-alanine (I), L-leucine (II), L-valine (III) and L-tert-leucine (IV) N-acetyl N'-methylamides were measured. Amides I-IV are not self associated in tetrachlormethane in the concentration 2 . 10-5 mol l-1 at room temperature and in tetrachloroethylene in the concentration 1.5 . 10-4 mol l-1 at temperatures above 65° C. True conformational changes are observable only with the least flexible amide IV which exists at room temperature in a C5 conformation. This conformational type is also highly populated in the valine derivative III, but is less important in the alanine and leucine derivatives I and II in which the intramolecularly bonded C7 and the distorted hydrogen-nonbonded conformations contribute seriously.

Effects of Rotation on Heat Transfer for a Single Row Jet Impingement Array With Crossflow

2012 ◽  
Vol 134 (8) ◽  
Author(s):  
Justin A. Lamont ◽  
Srinath V. Ekkad ◽  
Mary Anne Alvin
Keyword(s):  
Heat Transfer ◽  
Liquid Crystal ◽  
Rotation Number ◽  
Coriolis Force ◽  
Room Temperature ◽  
Turbine Blades ◽  
Target Surface ◽  
Channel Height ◽  
Potential Core ◽  
Single Row

The effects of the Coriolis force are investigated in rotating internal serpentine coolant channels in turbine blades. For complex flow in rotating channels, detailed measurements of the heat transfer over the channel surface will greatly enhance the blade designers’ ability to predict hot spots so coolant may be distributed more effectively. The present study uses a novel transient liquid crystal technique to measure heat transfer in a rotating, radially outward channel with impingement jets. A simple case with a single row of constant pitch impinging jets with the crossflow effect is presented to demonstrate the novel liquid crystal technique and document the baseline effects for this type of geometry. The present study examines the differences in heat transfer distributions due to variations in jet Rotation number, Roj, and jet orifice-to-target surface distance (H/dj = 1,2, and 3). Colder air, below room temperature, is passed through a room temperature test section to cause a color change in the liquid crystals. This ensures that buoyancy is acting in a similar direction as in actual turbine blades where walls are hotter than the coolant fluid. Three parameters were controlled in the testing: jet coolant-to-wall temperature ratio, average jet Reynolds number, Rej, and average jet Rotation number, Roj. Results show, such as serpentine channels, the trailing side experiences an increase in heat transfer and the leading side experiences a decrease for all jet channel height-to-jet diameter ratios (H/dj). At a jet channel height-to-jet diameter ratio of 1, the crossflow from upstream spent jets greatly affects impingement heat transfer behavior in the channel. For H/dj = 2 and 3, the effects of the crossflow are not as prevalent as H/dj = 1: however, it still plays a detrimental role. The stationary case shows that heat transfer increases with higher H/dj values, so that H/dj = 3 has the highest results of the three examined. However, during rotation the H/dj = 2 case shows the highest heat transfer values for both the leading and trailing sides. The Coriolis force may have a considerable effect on the developing length of the potential core, affecting the resulting heat transfer on the target surface.

scholarly journals Photo-tunable epsilon-near-zero behavior in a self-assembled liquid crystal – nanoparticle hybrid material

2021 ◽  
Author(s):  
Amit Bhardwaj ◽  
Vimala Sridurai ◽  
Sachin A. Bhat ◽  
Channabasaveshwar V. Yelamaggad ◽  
Geetha G. Nair
Keyword(s):  
Liquid Crystal ◽  
Hybrid Material ◽  
Room Temperature ◽  
Dynamic Tuning ◽  
Actinic Light ◽  
Self Assembled ◽  
Epsilon Near Zero

A room temperature stable self-assembled liquid crystal metamaterial exhibits dynamic tuning of the epsilon-near-zero (ENZ) bandwidth on illumination with actinic light in the optical regime.

A Room-Temperature Discotic Nematic Liquid Crystal

2000 ◽  
Vol 112 (17) ◽  
pp. 3270-3272 ◽  
Author(s):  
Sandeep Kumar ◽  
Sanjay Kumar Varshney
Keyword(s):  
Liquid Crystal ◽  
Nematic Liquid Crystal ◽  
Room Temperature
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