Search query: magic echo GaAs

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abstract: It was shown both theoretically and experimentally that isotropic indirect couplings in GaAs beyond the nearest neighbors can be measured accurately from the decays of Hahn echoes under fast magic angle spinning. In addition, homonuclear indirect couplings give rise to a shift of the spin echo timing which can be predicted precisely based on the measured isotropic indirect couplings. The decrease of isotropic indirect coupling with increasing distance between two nuclear spins is slower than the prediction of the theory on indirect couplings in semiconductors.
author_names: Larry D Potter

Yuan Ting Wu
title: NMR measurements of homonuclear indirect couplings in GaAs
year: 1995

abstract: We study decoherence of nuclear spins in a nanoscale GaAs device based on resistively detected nuclear magnetic resonance (NMR) We demonstrate how the spin echo technique can be modified for our system, and this is compared to the damping of Rabi type coherent oscillations. By selectively decoupling nuclear nuclear and electron nuclear spin, we determine decoherence rates due to individual mechanisms, namely, direct or indirect dipole coupling between different or like nuclides and electron nuclear spin coupling. The data reveal that the indirect dipole coupling between Ga and As mediated by conduction electrons has the strongest contribution, whereas the direct dipole coupling between them has the smallest, reflecting the magic angle condition between the As Ga bonds and the applied magnetic field.
author_names: Go Yusa

Norio Kumada

Koji Muraki

Yoshiro Hirayama
title: Individual Mechanisms of Nuclear Spin Decoherence in a Nanoscale GaAs NMR Device
year: 2005

abstract: Among the MR techniques playing on dipolar interaction (Hd) the magic sandwich echo sequence (MSE) is very seldom used in biological application. So far, the magic echo has been compared to the spin echo. However, MSE is closer to a stimulated echo thus a Magic Sandwich to Stimulated echo relative change (MaSteR) is of interest to study. The MaSteR evolution with spin lock intensity increase was studied for thawed tendon for different orientations within B0 to modulate the dipolar interaction. We show that MaSteR is correlated to dipolar interaction, sample composition and its evolution with orientation is sensitive to Hd sign. Summary (250 characters) A marker of macromolecular dipolar interactions (Hd) is introduced as the Magic Sandwich to Stimulated Echo relative change (MaSteR) Different B1 spin lock intensities are used to modulate Hd. MaSteR is sensitive to Hd sign and fiber orientation.
author_names: Eloise Mougel

Helene Ratiney

Eric Van Reeth

Kevin Tse-Ve-Koon

Kevin Tse Ve Koon

Olivier Beuf

Denis Grenier
title: Magic Sandwich to Stimulated Echo Relative change to identify sign and intensity of dipolar interaction in anisotropic tissue
year: 2020

abstract: To investigate the magic angle effect in three dimensional ultrashort echo time Cones Adiabatic T1r (3D UTE Cones AdiabT1r) imaging of articular cartilage at 3T.
author_names: Mei Wu

Yajun Ma

Akhil Kasibhatla

Mingxin Chen

Hyungseok Jang

Saeed Jerban

Eric Y Chang

Jiang Du
title: Convincing evidence for magic angle less sensitive quantitative T1r imaging of articular cartilage using the 3D ultrashort echo time cones adiabatic T1r (3D UTE cones AdiabT1r) sequence
venue: Magnetic resonance in medicine
year: 2020

abstract: The protons in collagen rich musculoskeletal (MSK) tissues such as the Achilles tendon are subject to strong dipolar interactions which are modulated by the term (3cos2th 1) where th is the angle between the fiber orientation and the static magnetic field B0. The purpose of this study was to investigate the magic angle effect in three dimensional ultrashort echo time Cones Adiabatic T1r (3D UTE Cones AdiabT1r) imaging of the Achilles tendon using a clinical 3 T scanner. The magic angle effect was investigated by Cones AdiabT1r imaging of five cadaveric human Achilles tendon samples at five angular orientations ranging from 0deg to 90deg relative to the B0 field. Conventional Cones continuous wave T1r (Cones CW T1r) and Cones T2* (Cones T2* sequences were also applied for comparison. On average, Cones AdiabT1r increased 3.6 fold from 13.6 1.5 ms at 0deg to 48.4 5.4 ms at 55deg, Cones CW T1r increased 6.1 fold from 7.0 1.1 ms at 0deg to 42.6 5.2 ms at 55deg, and Cones T2* increased 12.3 fold from 2.9 0.5 ms at 0deg to 35.8 6.4 ms at 55deg. Although Cones AdiabT1r is still subject to significant angular dependence, it shows a much reduced magic angle effect compared to Cones CW T1r and Cones T2* and may be used as a novel and potentially more effective approach for quantitative evaluation of the Achilles tendon and other MSK tissues.
author_names: Mei Wu

Yajun Ma

Lidi Wan

Saeed Jerban

Hyungseok Jang

Eric Y Chang

Jiang Du
title: Magic angle effect on adiabatic T1r imaging of the Achilles tendon using 3D ultrashort echo time cones trajectory
venue: NMR in biomedicine
year: 2020

abstract: In this work, we studied the photon echo from heavy hole excitons in a thin InGaAs/GaAs quantum well. To analyze the results, we used the model of an ensemble of two level systems. The model allows us to describe the temporal profile and the moment of arrival of the echo signal, as well as the echo amplitude decay with increasing delay between pulses. In addition, excitation induced dephasing effect was observed, that was beyond the limits of applicability of the model.
author_names: I I Yanibekov

I A Solovev

S A Eliseev

Yu P Efimov

V A Lovcjus

Yury V Kapitonov
title: Difference in the behavior of the photon echo of excitons in InGaAs/GaAs quantum wells from the predictions of the model of two level system ensemble
year: 2020

abstract: Time domain nuclear magnetic resonance techniques are frequently used in polymer, pharmaceutical, and food industries as they offer rapid experimentation and generally do not require any considerable preliminary sample preparation. Detection of solid and liquid fractions in a sample is possible with the free induction decay (FID) However, for the classical FID sequence that consists of a single pulse followed by relaxation decay acquisition, the dead time of the probe (ring out of resonance circuitry) occurs and varies between 5 and 15 ms for standard 10 mm tubes. In such a case, there arises a risk that the signal from the solid fraction cannot be detected correctly. To obtain quantitative measurement on crystalline and more mobile amorphous fractions, alternative sequences to the classical FID in the solid state nuclear magnetic resonance were developed. Solid echo and magic sandwich echo sequences perform the relaxation decay refocusing somehow excluding the dead time problem and allow detection of the signal from the solid fraction. In this study, knowledge of amorphous/crystal fraction, which is obtained through solid echo and magic sandwich echo, has been explored on powder sugar samples for the purpose of developing a groundwork for a reliable quality control method. Different sugars were examined for the utilization of the sequences. What is important to add and make this study unique is that the method proposed did not involve multiparameter fitting of the "bead" pattern FID signal that normally suffers from ambiguity; just the integration of the fast Fourier transform of the solid echo was needed to calculate the second moment, (M2)
author_names: Leonid Yu Grunin

Mecit Halil Oztop

Selen Guner

Saadet Fatma Baltaci
title: Exploring the crystallinity of different powder sugars through solid echo and magic sandwich echo sequences
venue: Magnetic resonance in chemistry MRC
year: 2019

abstract: Title Detection of nuclear spin coherence in GaAs through spin echo measurements using electrical spin injection [an abstract of dissertation and a summary of dissertation review] Author(s) Lin Zhi Chao Citation Bei Hai Dao Da Xue Bo Shi (Gong Xue Jia Di 13517Hao Issue Date 2019 03 25 Doc URL http:/hdl.handle.net/2115/74204 Rights(URL) https:/creativecommons.org/licenses/by nc sa/4.0/ Type theses (doctoral abstract and summary of review) Additional Information There are other files related to this item in HUSCAP. Check the above URL. File Information Zhichao_Lin_abstract.pdf (Lun Wen Nei Rong noYao Zhi
author_names: Lin Zhi Chao
title: Detection of nuclear spin coherence in GaAs through spin echo measurements using electrical spin injection [an abstract of dissertation and a summary of dissertation review]
year: 2019

abstract: Low field nuclear magnetic resonance (NMR) has been widely applied in the oil industry as a noninvasive technique for rock analysis. There are many organic compounds, such as kerogen, in unconventional shale resources. However, it is difficult to evaluate solid organic matter in shales using common NMR techniques. Previous work has shown the use of a solid echo on shale samples provides more information than the standard T1 T2 method with spin echo. But for multiple homonuclear dipolar coupling present in shales, solid echo is less efficient. We propose a new multimagic echo sequence for T1 and T1 T2 measurements. The magic echo and standard T1 and T2 measurement technologies are combined to provide a more complete evaluation of hydrogen containing shale sample components. Compared with other measurements, magic echo measurements provide more signal of organic matters in shale samples. The additional signal is contributed by homonuclear dipolar coupling in organic matter. The partial least squares regress.
author_names: Zijian Jia

Lizhi Xiao

Zhizhan Wang

Guangzhi Liao

Yan Zhang

Can Liang

Long Guo
title: Magic Echo for Nuclear Magnetic Resonance Characterization of Shales
year: 2017

abstract: Quantitative evaluation of the solid and viscous components of unconventional shale rock, namely kerogen and bitumen, is important for understanding reservoir quality. Short transverse coherence times, due to strong 1H 1H dipolar interactions, motivates the application of solid state refocusing pulse sequences that allow for investigating components of the free induction decay that are otherwise obscured by instrumental effects such as probe ringdown. This work reports on static, wide line 1H spectroscopy of shale rock and their extracted components, which include kerogen and bitumen, by the application of solid echo and magic echo pulse sequences. We characterize the efficiency of these cycles as a function of the radio frequency power and inter pulse spacing. Magic echos are shown to provide superior refocusing in comparison to solid echo based experiments, as can be understood from the truncation of the Magnus expansion and ability to also refocus any Iz Hamiltonians (e.g. static field inhomogeneity) We characterize the optimal echo spacing and RF power for two shale samples of different maturity, motivating routine core and cuttings analysis and applications.
author_names: Gregory S Boutis

Ravinath Kausik
title: Comparing the efficacy of solid and magic echo refocusing sequences: Applications to 1H NMR echo spectroscopy of shale rock.
venue: Solid state nuclear magnetic resonance
year: 2017