Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Imperfections in Crystal Structure: Point, Line and Plane Defects01:25

Imperfections in Crystal Structure: Point, Line and Plane Defects

144
A perfect crystal, in theory, has a uniform structure with the same unit cell and lattice points throughout. However, any deviation from this periodic arrangement is known as an imperfection or defect. These defects can be categorized into three types: point, line, and plane defects.Point defects occur when there is a deviation from the ideal due to missing atoms, displaced atoms, or additional atoms. These imperfections might occur due to imperfect packing during crystallization or because of...
144
Imperfections in Crystal Structure: Stoichiometric Point Defects01:26

Imperfections in Crystal Structure: Stoichiometric Point Defects

138
Schottky defects arise when some lattice points in a crystal, such as those in NaCl, remain unoccupied, creating lattice vacancies without disturbing the overall electrical neutrality of the crystal. This defect is common in ionic crystals where the positive and negative ions are similar in size, as seen in sodium chloride and cesium chloride. The presence of Schottky defects enables the crystal to conduct electricity to a small extent through an ionic mechanism. Electric fields cause nearby...
138
Imperfections in Crystal Structure: Non-Stoichiometric Defects01:29

Imperfections in Crystal Structure: Non-Stoichiometric Defects

111
Non-stoichiometric defects refer to a type of defect in the crystal structure of a compound where the ratio of its constituent elements deviates from the ideal stoichiometric ratio. There are two main types of non-stoichiometric defects: metal excess defects and metal deficiency defects.Metal excess defects occur when there is a slight surplus of metal ions than what is required by the stoichiometric ratio of the compound. For example, heating a sodium chloride crystal in sodium vapor results...
111
Tight Junctions01:29

Tight Junctions

6.8K
Tight junctions are molecular seals between cells that prevent the leaking of fluids, ions, and other small solutes across cavities and compartments in multicellular organisms. They are mainly composed of claudin and occludin transmembrane proteins, and other proteins such as tricellulin and JAM (junctional adhesion molecule). All these proteins are 4-pass transmembrane proteins, except JAM, which is a single-pass transmembrane protein belonging to the immunoglobulin superfamily. The...
6.8K
Structures of Solids02:22

Structures of Solids

17.7K
Solids in which the atoms, ions, or molecules are arranged in a definite repeating pattern are known as crystalline solids. Metals and ionic compounds typically form ordered, crystalline solids. A crystalline solid has a precise melting temperature because each atom or molecule of the same type is held in place with the same forces or energy. Amorphous solids or non-crystalline solids (or, sometimes, glasses) which lack an ordered internal structure and are randomly arranged. Substances that...
17.7K

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Screw symmetry, chiral hydrodynamics, and odd instability in active cholesterics.

Physical review. E·2025
Same author

Universal limiting behavior of reaction-diffusion systems with conservation laws.

Physical review. E·2025
Same author

Chirality and odd mechanics in active columnar phases.

PNAS nexus·2024
Same author

Biases in inverse Ising estimates of near-critical behavior.

Physical review. E·2023
Same author

Contact Topology and the Classification of Disclination Lines in Cholesteric Liquid Crystals.

Physical review letters·2023
Same author

Defect loops in three-dimensional active nematics as active multipoles.

Physical review. E·2022

Related Experiment Video

Updated: Apr 26, 2026

High-Contrast and Fast Photorheological Switching of a Twist-Bend Nematic Liquid Crystal
06:24

High-Contrast and Fast Photorheological Switching of a Twist-Bend Nematic Liquid Crystal

Published on: October 31, 2019

5.7K

Knotted defects in nematic liquid crystals.

Thomas Machon1, Gareth P Alexander1

  • 1Department of Physics and Centre for Complexity Science, University of Warwick, Coventry CV4 7AL, United Kingdom.

Physical Review Letters
|July 26, 2014
PubMed
Summary

The number of topological states for knotted defects in liquid crystals equals the link determinant. This research provides experimental identification methods and explores knot behavior and interactions.

Area of Science:

  • Materials Science
  • Condensed Matter Physics
  • Topology

Background:

  • Knotted defects in liquid crystals exhibit complex topological properties.
  • Understanding these topological states is crucial for predicting material behavior.

Purpose of the Study:

  • To quantify the number of distinct topological states associated with knotted defects in nematic liquid crystals.
  • To establish a link between topological states and the determinant of the corresponding link.
  • To explore experimental identification and consequences of these topological states.

Main Methods:

  • Utilizing topological theory to classify knotted defects.
  • Calculating the determinant of the link (L) to determine the number of topological states.
  • Simulating a Hopf link to illustrate topological classification.

More Related Videos

Forming, Confining, and Observing Microtubule-Based Active Nematics
08:37

Forming, Confining, and Observing Microtubule-Based Active Nematics

Published on: January 13, 2023

2.8K
Preparation of Monodomain Liquid Crystal Elastomers and Liquid Crystal Elastomer Nanocomposites
12:21

Preparation of Monodomain Liquid Crystal Elastomers and Liquid Crystal Elastomer Nanocomposites

Published on: February 6, 2016

12.5K

Related Experiment Videos

Last Updated: Apr 26, 2026

High-Contrast and Fast Photorheological Switching of a Twist-Bend Nematic Liquid Crystal
06:24

High-Contrast and Fast Photorheological Switching of a Twist-Bend Nematic Liquid Crystal

Published on: October 31, 2019

5.7K
Forming, Confining, and Observing Microtubule-Based Active Nematics
08:37

Forming, Confining, and Observing Microtubule-Based Active Nematics

Published on: January 13, 2023

2.8K
Preparation of Monodomain Liquid Crystal Elastomers and Liquid Crystal Elastomer Nanocomposites
12:21

Preparation of Monodomain Liquid Crystal Elastomers and Liquid Crystal Elastomer Nanocomposites

Published on: February 6, 2016

12.5K
  • Developing a heuristic for defect coarsening processes.

    • Main Results:

    • The number of distinct topological states is proven to be equal to the determinant of the link L.
    • Stable knots can be created in bulk cholesteric liquid crystals.
    • A method is provided to distinguish topological classes and predict defect crossings.

    Conclusions:

    • The determinant of a link provides a quantitative measure of topological states in liquid crystal defects.
    • This framework enables experimental identification and prediction of defect behavior and interactions.
    • The findings have implications for understanding and manipulating complex fluidic materials.