scholarly journals A Theoretical Design Approach for Passive Shimming of a Magic-Angle-Spinning NMR Magnet

2016 ◽  
Vol 26 (4) ◽  
pp. 1-4 ◽  
Author(s):  
Frank X. Li ◽  
John P. Voccio ◽  
Michael Sammartino ◽  
Min Cheol Ahn ◽  
Seungyong Hahn ◽  
...  
2014 ◽  
Vol 24 (3) ◽  
pp. 1-4 ◽  
Author(s):  
So Noguchi ◽  
Seungyong Hahn ◽  
Yukikazu Iwasa

Author(s):  
ASIF EQUBAL ◽  
Kan Tagami ◽  
Songi Han

In this paper, we report on an entirely novel way of improving the MAS-DNP efficiency by shaped μw pulse train irradiation for fast and broad-banded (FAB) saturation of the electron spin resonance. FAB-DNP achieved with Arbitrary Wave Generated shaped μw pulse trains facilitates effective and selective saturation of a defined fraction of the total electron spins, and provides superior control over the DNP efficiency under MAS. Experimental and quantum-mechanics based numerically simulated results together demonstrate that FAB-DNP significantly outperforms CW-DNP when the EPR-line of PAs is broadened by conformational distribution and exchange coupling. We demonstrate that the maximum benefit of FAB DNP is achieved when the electron spin-lattice relaxation is fast relative to the MAS frequency, i.e. at higher temperatures and/or when employing metals as PAs. Calculations predict that under short T<sub>1e </sub>conditions AWG-DNP can achieve as much as ~4-fold greater enhancement compared to CW-DNP.


2001 ◽  
Vol 4 (4) ◽  
pp. 333-351 ◽  
Author(s):  
G. Lippens ◽  
R. Warrass ◽  
J. Wieruszeski ◽  
P. Rousselot-Pailley ◽  
G. Chessari

1994 ◽  
Vol 49 (1-2) ◽  
pp. 19-26 ◽  
Author(s):  
B. Blümich

Abstract Recent developments, focussing on reduction of the rf excitation power by stochastic excitation, on improvements in sensitivity and excitation bandwidth by magic angle spinning, and on combining wideline spectroscopy with spatial resolution for investigations o f spatially inhomogeneous objects are reviewed.


2021 ◽  
Vol 2 (1) ◽  
pp. 39-48
Author(s):  
Nguyen H. H. Phuc ◽  
Takaki Maeda ◽  
Tokoharu Yamamoto ◽  
Hiroyuki Muto ◽  
Atsunori Matsuda

A solid solution of a 100Li3PS4·xLi3PO4 solid electrolyte was easily prepared by liquid-phase synthesis. Instead of the conventional solid-state synthesis methods, ethyl propionate was used as the reaction medium. The initial stage of the reaction among Li2S, P2S5 and Li3PO4 was proved by ultraviolet-visible spectroscopy. The powder X-ray diffraction (XRD) results showed that the solid solution was formed up to x = 6. At x = 20, XRD peaks of Li3PO4 were detected in the prepared sample after heat treatment at 170 °C. However, the samples obtained at room temperature showed no evidence of Li3PO4 remaining for x = 20. Solid phosphorus-31 magic angle spinning nuclear magnetic resonance spectroscopy results proved the formation of a POS33− unit in the sample with x = 6. Improvements of ionic conductivity at room temperature and activation energy were obtained with the formation of the solid solution. The sample with x = 6 exhibited a better stability against Li metal than that with x = 0. The all-solid-state half-cell employing the sample with x = 6 at the positive electrode exhibited a better charge–discharge capacity than that employing the sample with x = 0.


2018 ◽  
Vol 57 (14) ◽  
pp. 8390-8395 ◽  
Author(s):  
Bingtian Tu ◽  
He Zhang ◽  
Hao Wang ◽  
Weimin Wang ◽  
Zhengyi Fu

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