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Full-Text Articles in Physics

Rapid Acquisition Of Wideline Mas Solid-State Nmr Spectra With Fast Mas, Proton Detection, And Dipolar Hmqc Pulse Sequences, Aaron J. Rossini, Michael P. Hanrahan, Martin M. Thuo Jan 2016

Rapid Acquisition Of Wideline Mas Solid-State Nmr Spectra With Fast Mas, Proton Detection, And Dipolar Hmqc Pulse Sequences, Aaron J. Rossini, Michael P. Hanrahan, Martin M. Thuo

Materials Science and Engineering Publications

The solid-state NMR spectra of many NMR active elements are often extremely broad due to the presence of chemical shift anisotropy (CSA) and/or the quadrupolar interaction (for nuclei with spin I > 1/2). These NMR interactions often give rise to wideline solid-state NMR spectra which can span hundreds of kHz or several MHz. Here we demonstrate that by using fast MAS, proton detection and dipolar hetero-nuclear multiple-quantum (D-HMQC) pulse sequences, it is possible to rapidly acquire 2D spectra which correlate 1H chemical shifts to the indirectly detected wideline MAS powder patterns of dipolar coupled hetero-nuclei. The D-HMQC pulse sequence ...


Piezoelectric Ceramics With Compositions At The Morphotropic Phase Boundary In The Bifeo3–Pbzro3–Pbtio3 Ternary System, Wei Hu, Xiaoli Tan, Krishna Rajan Jan 2011

Piezoelectric Ceramics With Compositions At The Morphotropic Phase Boundary In The Bifeo3–Pbzro3–Pbtio3 Ternary System, Wei Hu, Xiaoli Tan, Krishna Rajan

Materials Science and Engineering Publications

Since ceramics in the PbZrO3–PbTiO3 binary system display excellent piezoelectric properties and those in BiFeO3–PbTiO3 exhibit high Curie temperatures, morphotropic phase boundary (MPB) compositions in the BiFeO3–PbZrO3–PbTiO3 ternary solid solution system are investigated for the development of piezoelectric ceramics for high temperature applications. It is found that the MPB compositions in the ternary system deviate away from the mixture of two binary MPB compositions 0.70BiFeO3–0.30PbTiO3 and 0.52PbZrO3–0.48PbTiO3. With decreasing amount of BiFeO3 in the MPB compositions in the ...


Relaxation In Glassforming Liquids And Amorphous Solids, C. Austin Angell, Kia L. Ngai, Greg B. Mckenna, Paul F. Mcmillan, Steve W. Martin Jan 2000

Relaxation In Glassforming Liquids And Amorphous Solids, C. Austin Angell, Kia L. Ngai, Greg B. Mckenna, Paul F. Mcmillan, Steve W. Martin

Materials Science and Engineering Publications

The field of viscousliquid and glassysolid dynamics is reviewed by a process of posing the key questions that need to be answered, and then providing the best answers available to the authors and their advisors at this time. The subject is divided into four parts, three of them dealing with behavior in different domains of temperature with respect to the glass transition temperature, Tg,and a fourth dealing with “short time processes.” The first part tackles the high temperature regime T>Tg, in which the system is ergodic and the evolution of the viscousliquid toward the condition at Tg is ...