14,134 research outputs found
Thermal fluctuations and anomalous elasticity of homogeneous nematic elastomers
We present a unified formulation of a rotationally invariant nonlinear
elasticity for a variety of spontaneously anisotropic phases, and use it to
study thermal fluctuations in nematic elastomers and spontaneously anisotropic
gels. We find that in a thermodynamic limit homogeneous nematic elastomers are
universally incompressible, are characterized by a universal ratio of shear
moduli, and exhibit an anomalous elasticity controlled by a nontrivial low
temperature fixed point perturbative in D=3-epsilon dimensions. In three
dimensions, we make predictions that are asymptotically exact.Comment: 4 RevTeX pgs,,submitted to Europhysics Letter
A systematic algorithm development for image processing feature extraction in automatic visual inspection : a thesis presented in partial fulfilment of the requirements for the degree of Master of Technology in the Department of Production Technology, Massey University
Image processing techniques applied to modern quality control are described together with the development of feature extraction algorithms for automatic visual inspection. A real-time image processing hardware system already available in the Department of Production Technology is described and has been tested systematically for establishing an optimal threshold function. This systematic testing has been concerned with edge strength and system noise information. With the a priori information of system signal and noise, non-linear threshold functions have been established for real time edge detection. The performance of adaptive thresholding is described and the usefulness of this nonlinear approach is demonstrated from results using machined test samples. Examination and comparisons of thresholding techniques applied to several edge detection operators are presented. It is concluded that, the Roberts' operator with a non-linear thresholding function has the advantages of being simple, fast, accurate and cost effective in automatic visual inspection
Universal Elasticity and Fluctuations of Nematic Gels
We study elasticity of spontaneously orientationally-ordered amorphous
solids, characterized by a vanishing transverse shear modulus, as realized for
example by nematic elastomers and gels. We show that local heterogeneities and
elastic nonlinearities conspire to lead to anomalous nonlocal universal
elasticity controlled by a nontrivial infared fixed point. Namely, at long
scales, such solids are characterized by universal shear and bending moduli
that, respectively, vanish and diverge at long scales, are universally
incompressible and exhibit a universal negative Poisson ratio and a non-Hookean
elasticity down to arbitrarily low strains. Based on expansion about five
dimensions, we argue that the nematic order is stable to thermal fluctuation
and local hetergeneities down to d_lc < 3.Comment: 4 RevTeX pgs, submitted to PR
Paving Spin-Wave Fibers in Magnonic Nanocircuits Using Spin-Orbit Torque
published_or_final_versio
Transition Form Factor with Tensor Current within the Factorization Approach
In the paper, we apply the factorization approach to deal with the
transition form factor with tensor current in the large recoil
regions. Main uncertainties for the estimation are discussed and we obtain
, where the first error is caused by the
uncertainties from the pionic wave functions and the second is from that of the
B-meson wave functions. This result is consistent with the light-cone sum rule
results obtained in the literature.Comment: 8 pages, 4 figures, references adde
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