Layer undulations induced by a magnetic or electric field in concentric cylindrical layers of smectic-A liquid crystals.

Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics · 1999 · Unclear · Insufficient evidence

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UnclearInsufficient evidencePaper 4023

The paper theoretically derives the critical magnetic field magnitude H(c) (azimuthal, parallel to layers) above which periodic smectic layer distortions are expected and energetically favorable. It also derives critical applied voltage magnitudes U(c) for an…

Study snapshot

PublicationPhysical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics · 1999

Study typeother

Reported directionUnclear

Evidence ratingInsufficient

Abstract

This paper derives theoretical results for the onset of Helfrich-Hurault-type transitions in samples of smectic-A liquid crystals arranged in concentric cylindrical layers [J. Chem. Phys. 55, 839 (1971); 59, 2068 (1973)]. A magnetic field is applied in the azimuthal direction, parallel to the layers. The governing equilibrium equation is solved in order to derive the critical magnitude H(c) of the magnetic field above which the onset of periodic smectic layer distortions is expected. The distortion solution is shown to be energetically favorable for H>H(c). Some examples of critical thresholds are given, by means of figures, for relevant physical parameters. The qualitative features of the solution at H(c) are displayed via the plot of a typical variable solution to the equilibrium equation in a particular case. The consequences of the results, especially the relationship between H(c) and the radial depth, are explored, and comparisons are drawn with known results for infinite planar aligned smectic-A samples. The results are also interpreted for the case of an electric field which follows the plane of the layers in the usual wedge geometry. Critical applied voltage magnitudes U(c) are derived for various radial sample depths and wedge angles.

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AI evidence extraction

Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.

Study typeother

Effect directionunclear

PopulationNot supplied

Sample sizeNot supplied

ExposureNot supplied

Evidence strengthInsufficientConfidence: 78% · Peer reviewed: yes

Main findings

Outcomes measured

Onset of Helfrich-Hurault-type transitions (periodic smectic layer distortions)
Critical magnetic field threshold H(c)
Critical applied voltage threshold U(c) (electric field case)

Limitations

The work is theoretical/derivational (no experimental or epidemiological data described in the abstract).
No exposure frequencies, field strengths (numerical values), or measurement methods are provided in the abstract.

View raw extracted JSON

{
  "study_type": "other",
  "exposure": {
    "band": null,
    "source": "magnetic field; electric field (wedge geometry)",
    "frequency_mhz": null,
    "sar_wkg": null,
    "duration": null
  },
  "population": null,
  "sample_size": null,
  "outcomes": [
    "Onset of Helfrich-Hurault-type transitions (periodic smectic layer distortions)",
    "Critical magnetic field threshold H(c)",
    "Critical applied voltage threshold U(c) (electric field case)"
  ],
  "main_findings": "The paper theoretically derives the critical magnetic field magnitude H(c) (azimuthal, parallel to layers) above which periodic smectic layer distortions are expected and energetically favorable. It also derives critical applied voltage magnitudes U(c) for an electric field case in wedge geometry for various radial sample depths and wedge angles.",
  "effect_direction": "unclear",
  "limitations": [
    "The work is theoretical/derivational (no experimental or epidemiological data described in the abstract).",
    "No exposure frequencies, field strengths (numerical values), or measurement methods are provided in the abstract."
  ],
  "evidence_strength": "insufficient",
  "confidence": 0.78,
  "peer_reviewed_likely": "yes",
  "keywords": [
    "smectic-A liquid crystals",
    "concentric cylindrical layers",
    "Helfrich-Hurault transition",
    "magnetic field",
    "electric field",
    "critical threshold",
    "layer undulations",
    "wedge geometry"
  ],
  "suggested_hubs": []
}

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AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.

Identifiers and source

DOI: 10.1103/physreve.60.1888
PubMed: 11969977

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