7Li+NMR quadrupolar splitting in stretched hydrogels: developments in relaxation time estimation fromz-spectra

2012 ◽  
Vol 50 ◽  
pp. S17-S21 ◽  
Author(s):  
Max Puckeridge ◽  
Bogdan E. Chapman ◽  
Philip W. Kuchel
Keyword(s):  
Relaxation Time ◽  
Time Estimation ◽  
Quadrupolar Splitting ◽  
7Li Nmr

scholarly journals Sub-Bottom Sediment Classification Using Reliable Instantaneous Frequency Calculation and Relaxation Time Estimation

2021 ◽  
Vol 13 (23) ◽  
pp. 4809
Author(s):  
Shaobo Li ◽  
Jianhu Zhao ◽  
Hongmei Zhang ◽  
Siheng Qu
Keyword(s):  
Relaxation Time ◽  
Instantaneous Frequency ◽  
Relaxation Times ◽  
Time Estimation ◽  
Variational Mode Decomposition ◽  
Time Data ◽  
Time Model ◽  
Sediment Types ◽  
Mode Decomposition ◽  
Time Map

The shift in IF (instantaneous frequency) series and the corresponding relaxation time have the potential to characterize sediment properties. However, these attributes derived from SBP (sub-bottom profiler) data are seldom used for offshore site investigations because of the unsoundness in attribute calculation. To overcome this problem, a new reliable method combining VMD (variational mode decomposition) and WVD (Wigner–Ville distribution), as well as relaxation time, is presented. Since the number of modes in classical VMD should be provided in advance, a modified VMD algorithm, MVMD (modified variational mode decomposition), is proposed here, where the distribution of the frequency domain of modes is taken into account to automatically determine the number of modes. Through the relaxation time model, the IF data of a series of pings calculated through MVMD-WVD are transformed into a relaxation time map. A robust estimation algorithm is applied to the relaxation time map to reduce the effects of interferences and obtain robust relaxation times. The final relaxation time data are used to determine the sediment types. Real data from SBP experiments, as well as borehole sampling and geotechnical analysis results, verified the good performance of the proposed method.

scholarly journals Relaxation Time Estimation from Complex Magnetic Resonance Images

Sensors ◽  
2010 ◽  
Vol 10 (4) ◽  
pp. 3611-3625 ◽  
Author(s):  
Fabio Baselice ◽  
Giampaolo Ferraioli ◽  
Vito Pascazio
Keyword(s):  
Relaxation Time ◽  
Magnetic Resonance ◽  
Time Estimation ◽  
Magnetic Resonance Images

scholarly journals Corneal relaxation time estimation as a function of tear oxygen tension in human cornea during contact lens wear

2019 ◽  
Vol 108 (1) ◽  
pp. 14-21
Author(s):  
Luis Felipe Del Castillo ◽  
Juanibeth G. Ramírez‐Calderón ◽  
Roxana M. Del Castillo ◽  
Marcel Aguilella‐Arzo ◽  
Vicente Compañ
Keyword(s):  
Relaxation Time ◽  
Oxygen Tension ◽  
Contact Lens ◽  
Time Estimation ◽  
Human Cornea ◽  
Contact Lens Wear ◽  
Lens Wear

Fully automatic cardiac T2* relaxation time estimation using marker-controlled watershed

2015 ◽  
Author(s):  
Kittichai Wantanajittikul ◽  
Suwit Saekho ◽  
Arintaya Phrommintikul ◽  
Nipon Theera-Umpon ◽  
Sansanee Auephanwiriyakul ◽  
...  
Keyword(s):  
Relaxation Time ◽  
Time Estimation ◽  
T2 Relaxation Time ◽  
T2 Relaxation ◽  
Fully Automatic

7Li NMR study of ionically conducting glasses

1998 ◽  
Vol 548 ◽  
Author(s):  
Tomoko Akai
Keyword(s):  
Activation Energy ◽  
Relaxation Time ◽  
Line Width ◽  
Activation Parameters ◽  
High Temperature Region ◽  
Lithium Ions ◽  
Nmr Study ◽  
7Li Nmr ◽  
Order Of Magnitude ◽  
Motional Narrowing

ABSTRACTTemperature dependence of 7Li NMR was measured in 50Li20-50B203 glasses. A new method for the analysis of motional narrowing of the line width (MNLW) incorporating Kohlrasuch-Williams-Watt (KWW) function, exp(-(t/τ)β) is presented. The obtained activation parameters are compared with that from conductivity. It was shown that MNLW can be explained by the same activation energy from conductivity. It was found that electrical relaxation time was an order of magnitude smaller than that from those from NMR line width. At high temperature region, where the line is well narrowed, a residual line width was observed. It is as large as 1 kHz, and gradually decreases with the increase in temperature. It was explained that there is a mobility difference in lithium ions in this glass. These results suggest that some fraction of ions are highly mobilized in the glass.

Magnetic resonance spin-spin relaxation time estimation in a rat model of fatty liver disease

2017 ◽  
Vol 47 (2) ◽  
pp. 468-476
Author(s):  
Sami Alghamdi ◽  
Benjamin Sinclair ◽  
Gary Cowin ◽  
Ian Brereton ◽  
Yasvir A. Tesiram
Keyword(s):  
Relaxation Time ◽  
Liver Disease ◽  
Magnetic Resonance ◽  
Fatty Liver ◽  
Spin Relaxation ◽  
Rat Model ◽  
Fatty Liver Disease ◽  
Time Estimation ◽  
Spin Relaxation Time ◽  
Resonance Spin

Automatic cardiac T2* relaxation time estimation from magnetic resonance images using region growing method with automatically initialized seed points

2016 ◽  
Vol 130 ◽  
pp. 76-86 ◽  
Author(s):  
Kittichai Wantanajittikul ◽  
Nipon Theera-Umpon ◽  
Suwit Saekho ◽  
Sansanee Auephanwiriyakul ◽  
Arintaya Phrommintikul ◽  
...  
Keyword(s):  
Relaxation Time ◽  
Magnetic Resonance ◽  
Region Growing ◽  
Time Estimation ◽  
Magnetic Resonance Images ◽  
T2 Relaxation Time ◽  
T2 Relaxation ◽  
Seed Points
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