کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5407030 1393199 2009 13 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Distributions of transverse relaxation times for soft-solids measured in strongly inhomogeneous magnetic fields
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
Distributions of transverse relaxation times for soft-solids measured in strongly inhomogeneous magnetic fields
چکیده انگلیسی
The single-sided NMR-MOUSE sensor that operates in highly inhomogeneous magnetic fields is used to record a CPMG 1H transverse relaxation decay by CPMG echo trains for a series of cross-linked natural rubber samples. Effective transverse relaxation rates 1/T2,short and 1/T2,long were determined by a bi-exponential fit. A linear dependence of transverse relaxation rates on cross-link density is observed for medium to large values of cross-link density. As an alternative to multi-exponential fits the possibility to analyze the dynamics of soft polymer network in terms of multi-exponential decays via the inverse Laplace transformation was studied. The transient regime and the effect of the T1/T2 ratio in inhomogeneous static and radiofrequency magnetic fields on the CPMG decays were studied numerically using a dedicated C++ program to simulate the temporal and spatial dependence of the CPMG response. A correction factor T2/T2,eff is derived as a function of the T1/T2 ratio from numerical simulations and compared with earlier results from two different well logging devices. High-resolution T1-T2 correlations maps are obtained by two-dimensional Laplace inversion of CPMG detected saturation recovery curves. The T1-T2 experimental correlations maps were corrected for the T1/T2 effect using the derived T2/T2,eff correction factor.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Magnetic Resonance - Volume 196, Issue 2, February 2009, Pages 178-190
نویسندگان
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