Characteristic parameters

Poole, Charles P.

doi:10.1016/b978-012561460-3/50010-2

Cited by 3 publications

(4 citation statements)

References 267 publications

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“…Using χ = − ∂ ∂φ Fint kT φ and the equilibrium condition we find (22) Thus, within the K model the φ dependence of χ K is due to P e (φ). In order to specify ∂χ K /∂φ it is first necessary to obtain ∂P e (φ)/∂φ by differentiating the equilibrium condition (20) with respect to φ leading to…”

Section: χ Within the K Modelmentioning

confidence: 99%

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Concentration Dependence of the Flory χ Parameter within Two-State Models

Baulin

Halperin

2002

Macromolecules

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The Flory χ parameter is typically assumed to depend only on the temperature, T . Experimental results often require the replacement of this χ(T ) by χ ef f , that depends also on the monomer volume fraction, φ, χ ef f (φ, T ). Such χ ef f (φ, T ) can arise from two state models, proposed for polyetheleneoxide (PEO) and other neutral water-soluble polymers. The predicted φ dependence of χ = χ ef f − (1 − φ)∂χ ef f /∂φ, obtainable from colligative properties, differs qualitatively between the various models: (i) The model of Karlstrom (J. Phys. Chem. 1985, 89, 4962) yields ∂χ/∂φ ≥ 0 while the model of Matsuyama and Tanaka (Phys. Rev. Lett. 1990, 65, 341) and of Bekiranov et al (Phys. Rev. E 1997, 55, 577) allows for ∂χ/∂φ < 0 (ii) χ(φ) as calculated from the Karlstrom model, utilizing the parameters used to fit the phase diagram of PEO, agrees semiquantitatively with the experimental values. On the other hand, χ(φ) similarly calculated from the model of Bekiranov et al differs qualitatively from the measured results. Altogether, χ(φ) provides useful measure for the performance of a model.

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Section: χ Within the K Modelmentioning

confidence: 99%

“…This is attributed to the existence of a preferred volume for a H-bond. [20] The application of pressure is assumed to introduces a geometric constraint resulting in a lower number of bound water molecules. This argument yields a semiquantitative agreement with experimental results on the phase diagram of PEO.…”

Section: Two "Two-state" Modelsmentioning

confidence: 99%

Concentration Dependence of the Flory χ Parameter within Two-State Models

Baulin

Halperin

2002

Macromolecules

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“…Middle reduced applied magnetic field, where the 𝐹 ⃗ (𝐽 ) line and 𝐹 ⃗ (𝐵) curve can be approximated by a median curve or line. Calculations based on Equations ( 21), ( 23) and ( 33) reveal the following values (for calculations, we used the Ginzburg-Landau 𝜅(𝑇) = 95 [39,53]): Equation (33) represents one of the simplest and, simultaneously, remarkably accurate mathematical expressions of our primary idea that → F p (J c , B, T) has three distinctive ranges (which we already mentioned above, but it is important to list these ranges again), each of which can be approximated by a linear curve:…”

Section: Rebco Thin Filmsmentioning

confidence: 99%

“…Calculations based on Equations ( 21), ( 23) and (33) reveal the following values (for calculations, we used the Ginzburg-Landau κ(T) = 95 [39,53]):…”

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confidence: 99%

New Scaling Laws for Pinning Force Density in Superconductors

Talantsev

2022

Condensed Matter

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Since the report by Fietz and Webb (Phys. Rev.1968, 178, 657–667), who considered the pinning force density, Fp→=Jc→×B→ (where Jc is the critical current density and B is applied magnetic flux density), in isotropic superconductors as a unique function of reduced magnetic field, BBc2 (where Bc2 is the upper critical field), Fp→ has been scaled based on the BBc2 ratio, for which there is a widely used Kramer–Dew–Hughes scaling law of Fp→B=Fp,maxBBc2p1−BBc2q, where Fp,max, Bc2, p, and q are free-fitting parameters. To describe Fp→B in high-temperature superconductors, the Kramer–Dew–Hughes scaling law has been modified by (a) an assumption of the angular dependence of all parameters and (b) by the replacement of the upper critical field, Bc2, by the irreversibility field, Birr. Here, we note that Fp→ is also a function of critical current density, and thus, the Fp→Jc scaling law should exist. In an attempt to reveal this law, we considered the full Fp→B,Jc function and reported that there are three distinctive characteristic ranges of BBc2,JcJcsf (where Jcsf is the self-field critical current density) on which Fp→B,Jc can be splatted. Several new scaling laws for Fp→Jc were proposed and applied to MgB2, NdFeAs(O,F), REBCO, (La,Y)H10, and YH6. The proposed scaling laws describe the in-field performance of superconductors at low and moderate magnetic fields, and thus, the primary niche for these laws is superconducting wires and tapes for cables, fault current limiters, and transformers.

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