The thesis describes the investigation of high-resolution MQ MAS NMR in rigid spin-1/2 systems. Formerly, MQC techniques were mainly applied to systems of small molecules, the newly developed MQC technique in this thesis, the 1H-MQC-filtered-MAS-NMR method, can be well applied to study the heterogeneity of inorganic and organic materials, such as silica gel, homopolymers, copolymers and their blends. In this thesis two multiple-pulse sequences were adopted: the three-pulse and the time-reversible eight-pulse sequence. The former has the advantage that the cycle time, i.e. the excitation time can be adjusted to arbitrary values, therefore it can be used to generate 1H MQC in coupled spin-1/2 systems for a wide range of dipolar interactions, especially to pump 1H MQC from a rigid system, such as the crystalline phase of polymers. But it has disadvantages: it is sensitive to chemical shifts and resonance offsets, and has low efficiency in exciting higher order coherences. The latter has higher efficiency in exciing higher order coherences and is not sensitive to chemical shifts and resonance offsets, but it has a long cycle time, so it is only effective when the dipolar interactions are not strong such as in the amorphous phase of polymers
| Identifer | oai:union.ndltd.org:DUETT/oai:DUETT:duett-05212001-074659 |
| Date | 21 May 2001 |
| Creators | Lin, Guangxin |
| Contributors | Veeman, Wiebren S |
| Publisher | Gerhard-Mercator-Universitaet Duisburg |
| Source Sets | Dissertations and other Documents of the Gerhard-Mercator-University Duisburg |
| Language | German |
| Detected Language | English |
| Type | text |
| Format | application/msword, text/html, application/pdf |
| Source | http://www.ub.uni-duisburg.de/ETD-db/theses/available/duett-05212001-074659/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. Hiermit erteile ich der Universitaet Duisburg das nicht-ausschliessliche Recht unter den unten angegebenen Bedingungen, meine Dissertation, Staatsexamens- oder Diplomarbeit, meinen Forschungs- oder Projektbericht zu veroeffentlichen und zu archivieren. Ich behalte das Urheberrecht[Mon May 21 07:43:51 2001] (eval 35): Bareword found where operator expected at (eval 35) line 2, near |
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