Lung lamellar body amphiphilic topography: A morphological evaluation using the continuum theory of liquid crystals: II. Disclinations, edge dislocations, and irregular defects

1988 ◽  
Vol 221 (1) ◽  
pp. 520-532 ◽  
Author(s):  
J. A. N. Zasadzinski ◽  
C. J. Stratton ◽  
R. Rudolphi

The continuum theory of nematics suggested in paper I is used to derive an expression for the quantity < P 2 (cos γ ( R ))>, where γ is the angle between the director at two points separated by a distance R . The result tends to the Maier-Saupe limit (S 2 2 , corresponding to no correlations of orientation) for large R , but to unity for small R , while for the value of R corresponding to the mean intermolecular spacing it is about S α 0 2 , with α 0 close to unity. It is suggested that continuum theory may be used to estimate <sin γ ( R )> as well. Two simple molecular models for nematics are discussed in the light of these results, one of them a simplified version of the model on which Maier & Saupe originally based their theory, and the other a steric model of the sort proposed by Onsager. Predictions based upon these models concerning the Frank stiffness constants - in particular, concerning their dependence on the order parameter S 2 at constant volume and temperature and upon wave number q - are found to be in partial but only partial agreement with experiment. An interesting problem concerning the entropy of misalignment and its effect upon the stiffness of a nematic is left unresolved.


1997 ◽  
Vol 8 (3) ◽  
pp. 281-291 ◽  
Author(s):  
C. V. BROWN ◽  
P. E. DUNN ◽  
J. C. JONES

The static electro-optic behaviour of achiral smectic C samples in the chevron geometry have been modelled using the continuum theory of Leslie et al. [1]. The model assumes that the layer tilt and smectic C director tilt angle are constant, and treats the layers at the chevron interface as an infinitely bound surface. Comparison of the predicted electro-optic behaviour with experimental results gives values for the bend (B1) and splay (B2) c-director elastic constants. However, more detailed optical studies show that surface and chevron interface terms become important at high values of applied electric field.


Nature ◽  
10.1038/16891 ◽  
1999 ◽  
Vol 397 (6717) ◽  
pp. 333-335 ◽  
Author(s):  
Eran Sharon ◽  
Jay Fineberg

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Dionysios Anninos ◽  
Beatrix Mühlmann

Abstract We explore the conjectured duality between a class of large N matrix integrals, known as multicritical matrix integrals (MMI), and the series (2m − 1, 2) of non-unitary minimal models on a fluctuating background. We match the critical exponents of the leading order planar expansion of MMI, to those of the continuum theory on an S2 topology. From the MMI perspective this is done both through a multi-vertex diagrammatic expansion, thereby revealing novel combinatorial expressions, as well as through a systematic saddle point evaluation of the matrix integral as a function of its parameters. From the continuum point of view the corresponding critical exponents are obtained upon computing the partition function in the presence of a given conformal primary. Further to this, we elaborate on a Hilbert space of the continuum theory, and the putative finiteness thereof, on both an S2 and a T2 topology using BRST cohomology considerations. Matrix integrals support this finiteness.


Sign in / Sign up

Export Citation Format

Share Document