Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Analysis of theoretical NMR spectra generated by exact solutions of the
  Bloch-McConnell and the Bloch-Torrey equations for a two-compartment radial
  diffusive exchange model   Diffusive spin exchange is one of the most important relaxation mechanisms in
the Nuclear Magnetic Resonance (NMR) applications to medicine and biology. Two
models based on the Bloch-McConnell (B-M) and the Bloch-Torrey (B-T) equations
are commonly used for modelling the physical processes which determine the NMR
lineshapes. Qualitative arguments for each of the two methods can be found in
various studies in the literature. However, there is a lack of systematic
quantitative investigations of the diffusive exchange spectra calculated with
the two methods for the same physical system or model. In this work exact
frequency-domain transverse magnetization solutions of the B-M and the B-T
equations with boundary conditions for a two-compartment radial diffusive
exchange model are presented. Theoretical spectra and the two corresponding
metrics were computed by varying three different parameters: diffusive
permeability of the separating membrane between the two compartments (P), the
radius of the inner spherical compartment (a), and the chemical shift between
the two compartments (\Deltaf). In general, the two models predicted different
spectral broadening for the same parameters in agreement with the different
analytical solutions. However, the numerical analysis of the spectral
broadening demonstrated that the two models converge to the same results in the
limit of large chemical shift on the scale of the exchange rate. The results
were qualitatively interpreted based on the difference between the two models:
the B-M model assumes a single average exchange time constant while the B-T
model implies a more realistic continuous distribution of diffusive exchange
times.

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The categories of this paper are: atom-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: mtrl-th
2
The categories of this paper are: math
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The categories of this paper are: dg-ga
9
The categories of this paper are: nlin
12
The categories of this paper are: nucl-th
10
The categories of this paper are: q-bio
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The categories of this paper are: solv-int
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The categories of this paper are: econ
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The categories of this paper are: comp-gas
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The categories of this paper are: chem-ph
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The categories of this paper are: q-alg
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The categories of this paper are: gr-qc
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The categories of this paper are: quant-ph
11
The categories of this paper are: hep-lat