Linked Life Data

17804799

Source:http://linkedlifedata.com/resource/pubmed/id/17804799

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
37
pubmed:dateCreated
2007-9-12
pubmed:abstractText
One fascinating high-pressure behavior of tetrahedral glasses and melts is the local coordination change with increasing pressure, which provides a structural basis for understanding numerous anomalies in their high-pressure properties. Because the coordination change is often not retained upon decompression, studies must be conducted in situ. Previous in situ studies have revealed that the short-range order of tetrahedrally structured glasses and melts changes above a threshold pressure and gradually transforms to an octahedral form with further pressure increase. Here, we report a thermal effect associated with the coordination change at given pressures and show distinct thermal behaviors of GeO(2) glass in tetrahedral, octahedral, and their intermediate forms. An unusual thermally induced densification, as large as 16%, was observed on a GeO(2) glass at a pressure of 5.5 gigapascal (GPa), based on in situ density and x-ray diffraction measurements at simultaneously high pressures and high temperatures. The large thermal densification at high pressure was found to be associated with the 4- to 6-fold coordination increase. Experiments at other pressures show that the tetrahedral GeO(2) glass displayed small thermal densification at 3.3 GPa arising from the relaxation of intermediate range structure, whereas the octahedral glass at 12.3 GPa did not display any detectable thermal effects.
pubmed:commentsCorrections
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0027-8424
pubmed:author
pubmed:issnType
Print
pubmed:day
11
pubmed:volume
104
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
14576-9
pubmed:dateRevised
2010-9-16
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Distinct thermal behavior of GeO2 glass in tetrahedral, intermediate, and octahedral forms.
pubmed:affiliation
High Pressure Collaborative Access Team, Geophysical Laboratory, Carnegie Institution of Washington, Argonne, IL 60439, USA. gshen@hpcat.aps.anl.gov
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S.