Bestand wählen
Merken

Liquid Crystals - Electrically Induced Alterations in Texture during Nematic Phases

Zitierlink des Filmsegments
Embed Code

Automatisierte Medienanalyse

Beta
Erkannte Entitäten
Sprachtranskript
Under the influence of an alternating electric field, the homogeneously orientated film is transformed into a pattern of parallel strips. These so called "Williams domains" first become unstable at the lower left-hand corner. At maximum field strength, the whole plane of vision exhibits dynamic scattering.Williams
domains develop again from the homogeneously orientated structure. Two dislocations move diagonally from the lower left-hand corner to the upper left-hand corner. From these dislocations of the strips, a knitting pattern evolves. A further increase in field strength finally leads to dynamic scattering.This general view
shows the formation of Williams domains, which are stable at low field strength. The number of disinclinations increases with increasing field strength. Formation of knitting pattern. Onset of dynamic scattering.More details can be seen at higher magnification. Williams domains with disinclinations. Formation of knitting pattern.
Start of dynamic scattering.A less stable strip pattern is formed. The strips continually move in relation to one another. This motion intensifies with increasing field strength. Finally dynamic scattering occurs.Increase in field strength leads to the formation of Williams domains.
Dynamic scattering at maximum field strength. With decreasing field strength, the strip pattern with the original spacing between strips is
resumed.Williams domains are also formed
with an increasing constant field. They decompose into a knitting pattern which is stable over a large voltage range. Finally, at maximum field strength the dynamic scattering starts at specific sites. Other parts remain static.By decreasing the field strength, a system of paired disinclinations connected
by dark strips is formed. Most of these structures dissolve rapidly. Three pairs of disinclinations remain. The disinclinations of the
pair at the lower right-hand corner attract one another. They
approach mutually with increasing speed and finally extinguish each other.Dynamic
scattering. Formation of a large number of disinclinations. On the
extreme left, four connected disinclinations approach each other - and extinguish mutually. This is a so called "healing process". The two other pairs of disinclinations remain stable.In this last experiment
the alternating field is increased continuously. - Then the voltage is reduced step-wise. The voltage jumps are accompanied by sudden changes of colour.
Methoxygruppe
Körpertemperatur
Computeranimation
Strippen
Chemische Struktur
Molekulardynamik
Domäne <Biochemie>
Computeranimation
Strippen
Bewegung
Molekulardynamik
Setzen <Verfahrenstechnik>
Domäne <Biochemie>
Strippen
Replikationsursprung
Molekulardynamik
Domäne <Biochemie>
Computeranimation
Strippen
Chemische Struktur
Systemische Therapie <Pharmakologie>
Allende-Meteorit
Computeranimation
Stromschnelle
Aktives Zentrum
Setzen <Verfahrenstechnik>
Mikroskopie
Computeranimation
Computeranimation

Metadaten

Formale Metadaten

Titel Liquid Crystals - Electrically Induced Alterations in Texture during Nematic Phases
Alternativer Titel Flüssige Kristalle - Elektrisch induzierte Texturänderungen bei nematischen Phasen
Autor Sackmann, Erich
Lizenz CC-Namensnennung - keine kommerzielle Nutzung - keine Bearbeitung 3.0 Deutschland:
Sie dürfen das Werk bzw. den Inhalt in unveränderter Form zu jedem legalen und nicht-kommerziellen Zweck nutzen, vervielfältigen, verbreiten und öffentlich zugänglich machen, sofern Sie den Namen des Autors/Rechteinhabers in der von ihm festgelegten Weise nennen.
DOI 10.3203/IWF/E-2422eng
IWF-Signatur E 2422
Herausgeber IWF (Göttingen)
Erscheinungsjahr 1977
Sprache Englisch
Produzent IWF
Produktionsjahr 1974

Technische Metadaten

IWF-Filmdaten Film, 16 mm, LT, 76 m ; F, 7 min

Inhaltliche Metadaten

Fachgebiet Chemie
Abstract Transition at three threshold voltages (transition field strengths) to a) a band-like domain pattern of high symmetry (Williams-domains), b) a still regular domain structure of lower symmetry (decomposition of the bands), and c) a completely turbulent state (dynamic scattering regime). Interaction between disclination lines (defects in molecular orientation) after switching off the electric field.
Schlagwörter disclination lines
ferroelectric domains
domains, ferroelectric
liquid crystals
crystals / liquid crystals
nematic phase
texture, nematic
Weiss domain
Williams domains

Zugehöriges Material

Ähnliche Filme

Loading...
Feedback