La communication hospitalière

Carayol, Valérie

doi:10.4000/communicationorganisation.2980

Cited by 2 publications

(2 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is evident from the present study that it is in fact orthorhombic-see table 2. It should be noted that the 'tetragonal' high-pressure phases of ZrO 2 , HfO 2 and MnF 2 have also all been shown to be orthorhombic [26][27][28]. The volume change between the cubic and orthorhombic phases of PbO 2 is 1.4(1)% at 11.4 GPa.…”

Section: Phase IVmentioning

confidence: 96%

The high-pressure phase transition sequence from the rutile-type through to the cotunnite-type structure in

Haines

Léger

Schulte

1996

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

Four phase transitions were observed in under pressure up to 47 GPa using x-ray diffraction in a diamond anvil cell. At close to 4 GPa, rutile-structured underwent a second-order transition to an orthorhombic, -type phase. Above 7 GPa, this -type phase transformed to a cubic phase with a modified fluorite structure. A transition to an orthorhombic phase was observed at 11.4 GPa. The intensities of the diffraction lines in this orthorhombic phase indicate a displacement of the lead ions from the fcc positions occupied in the cubic phase. This orthorhombic phase has similar cell constants (a = 10.027(2) Å, b = 5.246(1) Å, and c = 5.116(1) Å at 26 GPa) to the orthorhombic I phase of and also that of , and could be isostructural. A further transition began above 29 GPa to a cotunnite-type phase, with space group Pnam, and Z = 4, and with a = 5.443(18) Å, b = 6.346(17) Å, and c = 3.368(8) Å at 47 GPa. The coordination number of the lead ion is 6 in the first two phases, 6 + 2 in phase III, most probably 7 in phase IV and 9 in phase V. The volume decreases observed in the three first-order transitions are 6.9, 1.4, and 7.5% at 7, 11.4, and 29 GPa, respectively. The two higher-pressure transitions were reversible, whereas the cubic phase transformed to upon decompression, and this was retained down to ambient pressure. This is the first time a cotunnite-type structure has been adopted by a group IVb dioxide, which has implications for the high-pressure behaviour of the homologous compounds with smaller cations: and .

show abstract

Section: Phase IVmentioning

confidence: 96%

The high-pressure phase transition sequence from the rutile-type through to the cotunnite-type structure in

Haines

Léger

Schulte

1996

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

show abstract

“…Innovation systems approaches focus the attention of policy makers on the existence of situations where the relationships between different actors in the system are weak, and where divergent cultural traits and organisational practices pose a barrier to the collaboration and coordination among different actors in a system. There has been abundant research about the study of these relationships, especially in areas like university-industry linkages where cultural differences and other barriers have hampered a fluid relationship between the universities and their economic environment (Agrawal, 2001;Carlson et al, 2002;Carayol, 2003).…”

mentioning

confidence: 99%