Carbon-13 NMR studies of solid phenolic resins using cross polarization and magic-angle spinning

1983 ◽  
Vol 16 (10) ◽  
pp. 1669-1672 ◽  
Author(s):  
Richard L. Bryson ◽  
Galen R. Hatfield ◽  
Thomas A. Early ◽  
Allen R. Palmer ◽  
Gary E. Maciel
Keyword(s):  
Magic Angle Spinning ◽  
Magic Angle ◽  
Cross Polarization ◽  
Nmr Studies ◽  
Phenolic Resins ◽  
Angle Spinning

Cross-polarization/magic-angle spinning NMR studies of polymorphism: Cortisone acetate

1990 ◽  
Vol 46 (6) ◽  
pp. 927-935 ◽  
Author(s):  
Robin K. Harris ◽  
Alan M. Kenwright ◽  
Barry J. Say ◽  
Race R. Yeung ◽  
Richard A. Fletton ◽  
...  
Keyword(s):  
Magic Angle Spinning ◽  
Cortisone Acetate ◽  
Magic Angle ◽  
Cross Polarization ◽  
Nmr Studies ◽  
Angle Spinning

Solid-state NMR studies of cadmium: 113Cd1H cross polarization and magic-angle spinning

1980 ◽  
Vol 41 (1) ◽  
pp. 158-168 ◽  
Author(s):  
T.T.P Cheung ◽  
L.E Worthington ◽  
P.Dubois Murphy ◽  
B.C Gerstein
Keyword(s):  
Solid State ◽  
Solid State Nmr ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Cross Polarization ◽  
Nmr Studies ◽  
Angle Spinning

Carbon-13 NMR studies of solid urea-formaldehyde resins using cross polarization and magic-angle spinning

1983 ◽  
Vol 16 (4) ◽  
pp. 598-604 ◽  
Author(s):  
Gary E. Maciel ◽  
Nikolaus M. Szeverenyi ◽  
Thomas A. Early ◽  
George E. Myers
Keyword(s):  
Urea Formaldehyde ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Cross Polarization ◽  
Nmr Studies ◽  
Angle Spinning

13C cross-polarization/magic angle spinning NMR studies of ?-elastin preparations show retention of overall structure and reduction of mobility with a decreased number of cross-links

Biopolymers ◽  
2001 ◽  
Vol 59 (4) ◽  
pp. 266-275 ◽  
Author(s):  
Kristin K. Kumashiro ◽  
Minna S. Kim ◽  
Sylvia E. Kaczmarek ◽  
Lawrence B. Sandberg ◽  
Charles D. Boyd
Keyword(s):  
Magic Angle Spinning ◽  
Magic Angle ◽  
Cross Polarization ◽  
Nmr Studies ◽  
Cross Links ◽  
Angle Spinning

scholarly journals Conversion of sub-µm calcium carbonate (calcite) particles to hollow hydroxyapatite agglomerates in K2HPO4 solutions

2020 ◽  
Vol 9 (1) ◽  
pp. 945-960
Author(s):  
Sun Yanyan ◽  
Wang Guangxin ◽  
Li Wuhui ◽  
Wang Yaming ◽  
Satoshi Hayakawa ◽  
...  
Keyword(s):  
Activation Energy ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Cross Polarization ◽  
X Ray Diffraction ◽  
Nmr Studies ◽  
X Ray ◽  
Order Of Magnitude ◽  
Angle Spinning ◽  
Cp Mas Nmr

AbstractSub-µm CaCO3 (calcite; CC) particles were converted to calcium monohydrogenphosphate dihydrate (DCPD) and hydroxyapatite (HAp) via soaking treatments in K2HPO4 solutions with varied pH (3–12) and concentrations (0.1–1.5 M) at 37°C for up to 10 days. DCPD was derived from the solutions with pH ≤ 6; while hollow HAp was yielded when pH ≥ 7 in assemblies of petal-like crystallites. Results of magic angle spinning (MAS) and cross-polarization magic angle spinning (CP-MAS) NMR studies have shown that the HAp lattice has only PO42− but no HPO42− at B (phosphate) sites. Trace amounts of CO32− have occupied both A (OH) and B (PO4) sites, and H2O is adsorbed on surface crystallites. The primary crystallite size of HAp derived from Scherrer equation increases quickly in a 12 h period and becomes gradually stable afterward. Samples of particles soaked within 3 h in a temperature range of 20–80°C were analyzed by X-ray diffraction. It is shown that the rate constant of 1 M solution is about an order of magnitude greater than that of 0.1 M solution and the apparent activation energy is 33 kJ/mol. In this work, the conversion of CC to HAp can be quantitatively controlled to solve the problem of slow degradation of HAp.

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