Effect of the temperature range of the nematic phase on the induction of a twist grain boundary phase in non-chiral liquid crystals

The effect of pressure on several mesogens which possess a strongly polar terminal group (CN or NO2 ) is studied. In all cases the partially bilayer smectic A (Ad) gets bounded while the nematic phase gets more stabilised at high pressures. In the case of reentrant nematogens, the maximum pressure of smectic stability is seen to be related to the temperature range of the nematic phase at 1 bar.

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Ориентационный порядок в жидкокристаллических комплексах на основе лантаноидов

Физика твердого тела ◽

10.21883/ftt.2018.04.45697.227 ◽

2018 ◽

Vol 60 (4) ◽

pp. 805

Author(s):

Л.А. Добрун ◽

А.П. Ковшик ◽

Е.И. Рюмцев ◽

А.А. Калинкин

Keyword(s):

Liquid Crystal ◽

Liquid Crystals ◽

Nematic Phase ◽

Organic Liquid ◽

Orientational Order ◽

Complexing Agent ◽

Temperature Range ◽

First Time

AbstractIn this study, we have for the first time determined the degree of an orientational order S for a series of liquid-crystal complexes based on lanthanides (Eu^+3, Gd^+3, Tb^+3, Dy^+3) with the same ligand composition in the temperature range of existence of the nematic phase by using experimental refractometry results. We have also found an even-odd alternative S as number of protons in the ions complexing agent has consecutively increased. The obtained values of S have been compared with the corresponding degrees of order of the calamite organic liquid crystals.

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Monosubstituted ferrocene liquid crystals containing click triazole with a wide nematic phase temperature range

Liquid Crystals ◽

10.1080/02678292.2017.1282047 ◽

2017 ◽

Vol 44 (9) ◽

pp. 1450-1461 ◽

Cited By ~ 5

Author(s):

Haomin Cheng ◽

Chao Ma ◽

Yao Chen ◽

Hai-liang Ni ◽

Chun Feng ◽

...

Keyword(s):

Liquid Crystals ◽

Nematic Phase ◽

Temperature Range ◽

Phase Temperature

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Examination of Fracture Interfaces in Silicon Nitride

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100113925 ◽

1975 ◽

Vol 33 ◽

pp. 60-61

Author(s):

Nancy J. Tighe

Keyword(s):

Silicon Nitride ◽

Grain Boundary ◽

Crack Growth ◽

Subcritical Crack Growth ◽

Slow Crack Growth ◽

Ceramic Materials ◽

Grain Boundary Sliding ◽

Boundary Phase ◽

Turbine Engines ◽

Boundary Sliding

Silicon nitride is one of the ceramic materials being considered for the components in gas turbine engines which will be exposed to temperatures of 1000 to 1400°C. Test specimens from hot-pressed billets exhibit flexural strengths of approximately 50 MN/m2 at 1000°C. However, the strength degrades rapidly to less than 20 MN/m2 at 1400°C. The strength degradition is attributed to subcritical crack growth phenomena evidenced by a stress rate dependence of the flexural strength and the stress intensity factor. This phenomena is termed slow crack growth and is associated with the onset of plastic deformation at the crack tip. Lange attributed the subcritical crack growth tb a glassy silicate grain boundary phase which decreased in viscosity with increased temperature and permitted a form of grain boundary sliding to occur.

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