Dynamical correlation from topological solitons in two-dimensional anisotropic models

1992 ◽  
Vol 89 (1) ◽  
pp. 109-114 ◽  
Author(s):  
A. R. Pereira ◽  
A. S. T. Pires ◽  
M. E. Gouv�a ◽  
B. V. Costa
Keyword(s):  
Two Dimensional ◽  
Dynamical Correlation ◽  
Topological Solitons ◽  
Anisotropic Models

Dynamic topological solitons in a two-dimensional ferromagnet

1999 ◽  
Vol 88 (4) ◽  
pp. 833-843 ◽  
Author(s):  
A. A. Zhmudskii ◽  
B. A. Ivanov
Keyword(s):  
Two Dimensional ◽  
Topological Solitons

Cardiac microimpedance measurement in two-dimensional models using multisite interstitial stimulation

2006 ◽  
Vol 290 (5) ◽  
pp. H1976-H1987 ◽  
Author(s):  
Andrew E. Pollard ◽  
Roger C. Barr
Keyword(s):  
Test Data ◽  
Ventricular Myocytes ◽  
Electrophysiological Study ◽  
Two Dimensional ◽  
Dynamic Membrane ◽  
Anisotropic Models ◽  
Wide Range ◽  
Dimensional Models ◽  
Generate Test Data ◽  
Interstitial Potential

We analyzed central interstitial potential differences during multisite stimulation to assess the feasibility of using those recordings to measure cardiac microimpedances in multidimensional preparations. Because interstitial current injected and removed using electrodes with different proximities allows modulation of the portion of current crossing the membrane, we hypothesized that multisite interstitial stimulation would give rise to central interstitial potential differences that depend on intracellular and interstitial microimpedances, allowing measurement of those microimpedances. Simulations of multisite stimulation with fine and wide spacing in two-dimensional models that included dynamic membrane equations for guinea pig ventricular myocytes were performed to generate test data (∂φo). Isotropic interstitial and intracellular microimpedances were prescribed for one set of simulations, and anisotropic microimpedances with unequal ratios (intracellular to interstitial) along and across fibers were prescribed for another set of simulations. Microimpedance measurements were then obtained by making statistical comparisons between ∂φo values and interstitial potential differences from passive bidomain simulations (Δφo) in which a wide range of possible microimpedances were considered. Possible microimpedances were selected at 25% increments. After demonstrating the effectiveness of the overall method with microimpedance measurements using one-dimensional test data, we showed microimpedance measurements within 25% of prescribed values in isotropic and anisotropic models. Our findings suggest that development of microfabricated devices to implement the procedure would facilitate routine measurement as a component of cardiac electrophysiological study.

scholarly journals Vortices in Two- Dimensional Anisotropic   Models

1981 ◽  
Vol 65 (1) ◽  
pp. 164-171 ◽  
Author(s):  
T. Watanabe ◽  
H. Otsu
Keyword(s):  
Two Dimensional ◽  
Anisotropic Models

Structure Analysis of Poly(N-isopropylacrylamide) Using Near-Infrared Spectroscopy and Generalized Two-Dimensional Correlation Infrared Spectroscopy

2007 ◽  
Vol 61 (7) ◽  
pp. 765-771 ◽  
Author(s):  
Bingjie Sun ◽  
Yinan Lin ◽  
Peiyi Wu
Keyword(s):  
Infrared Spectroscopy ◽  
Conformational Changes ◽  
Near Infrared ◽  
Variable Temperature ◽  
Chemical Mechanism ◽  
Heating Process ◽  
Two Dimensional ◽  
Dynamical Correlation ◽  
Hydrocarbon Chains ◽  
Combination Bands

Based on a detailed study of the fundamental vibrations in the mid-infrared (MIR) region and supported by NH-proton deuteration results, the assignment of the overtone and combination bands in the near-infrared (NIR) spectrum of poly(N-isopropylacrylamide) (PNIPAM) is presented. Variable-temperature experiments and two-dimensional correlation infrared spectroscopy are used to determine the chemical mechanism and changing sequence of groups in PNIPAM; we conclude that bonded NH groups turn into free NH groups during the heating process, while the CH groups on the side-chains change prior to those on the main chains. A heterospectral dynamical correlation between the NIR and MIR regions or H-included groups in both regions was also performed. The temperature-induced dissociation of the hydrogen-bonded NH groups is found to proceed earlier than the conformational changes in the hydrocarbon chains.

scholarly journals Steady Flux Regime During Convective Mixing in Three-Dimensional Heterogeneous Porous Media

Fluids ◽  
2018 ◽  
Vol 3 (3) ◽  
pp. 58 ◽  
Author(s):  
Christopher Green ◽  
Jonathan Ennis-King
Keyword(s):  
Porous Media ◽  
Three Dimensional ◽  
Heterogeneous Porous Media ◽  
Three Dimensions ◽  
Two Dimensional ◽  
Anisotropic Porous Media ◽  
Initial Flow ◽  
Anisotropic Models ◽  
Convective Mixing ◽  
Heterogeneous Models

Density-driven convective mixing in porous media can be influenced by the spatial heterogeneity of the medium. Previous studies using two-dimensional models have shown that while the initial flow regimes are sensitive to local permeability variation, the later steady flux regime (where the dissolution flux is relatively constant) can be approximated with an equivalent anisotropic porous media, suggesting that it is the average properties of the porous media that affect this regime. This work extends the previous results for two-dimensional porous media to consider convection in three-dimensional porous media. Through the use of massively parallel numerical simulations, we verify that the steady dissolution rate in the models of heterogeneity considered also scales as k v k h in three dimensions, where k v and k h are the vertical and horizontal permeabilities, respectively, providing further evidence that convective mixing in heterogeneous models can be approximated with equivalent anisotropic models.

scholarly journals Charges and Electromagnetic Radiation as Topological Excitations

2017 ◽  
Vol 2017 ◽  
pp. 1-9
Author(s):  
Manfried Faber
Keyword(s):  
Electromagnetic Radiation ◽  
Minkowski Space ◽  
Degrees Of Freedom ◽  
Photon Number ◽  
Two Dimensional ◽  
Topological Solitons ◽  
Topological Excitations ◽  
Quantum Numbers ◽  
Topological Quantum ◽  
Three Degrees Of Freedom

We discuss a model with stable topological solitons in Minkowski space with only three degrees of freedom, the rotational angles of a spatial Dreibein. This model has four types of solitons differing in two topological quantum numbers which we identify with electric charge and spin. The vacuum has a two-dimensional degeneracy leading to two types of massless excitations, characterised by a topological quantum number which could have a physical equivalent in the photon number.

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