X-ray Powder Diffraction Structure Reinvestigation of the α and β Forms of Cobalt Phthalocyanine and Kinetics of the α → β Phase Transition

1998 ◽  
Vol 120 (49) ◽  
pp. 12798-12807 ◽  
Author(s):  
Paolo Ballirano ◽  
Ruggero Caminiti ◽  
Claudio Ercolani ◽  
Adriana Maras ◽  
Maria Antonietta Orrù
Keyword(s):  
Phase Transition ◽  
Powder Diffraction ◽  
Cobalt Phthalocyanine ◽  
X Ray ◽  
Β Phase ◽  
Diffraction Structure ◽  
Kinetics Of

Neutron and X-Ray Diffraction Studies of Piezoelectric Materials under Non-Ambient Conditions

2004 ◽  
Vol 443-444 ◽  
pp. 277-282
Author(s):  
J. Haines ◽  
O. Cambon ◽  
J. Rouquette ◽  
V. Bornand ◽  
Ph. Papet ◽  
...  
Keyword(s):  
Phase Transition ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Piezoelectric Materials ◽  
Germanium Dioxide ◽  
Raman Signal ◽  
Imaging Plate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Β Phase

In depth study of the crystal structures of piezoelectric materials as a function of temperature, pressure and composition allows for the design and optimization of such materials and defines the conditions of their use in technological applications. Results from studies on two classes of piezoelectric materials are described, the α-quartz group and the ferroelectric perovskite group. The structures of α-quartz-type germanium dioxide and iron phosphate were refined at high temperatures by the Rietveld method using time-of-flight neutron powder diffraction data. The α-β phase transition occurs at 980 K in FePO4, whereas for GeO2, no β phase is observed. The intertetrahedral bridging angle θ and the tilt angle δ in GeO2exhibit thermal stabilities that are significantly greater than α-quartz. The temperature dependence of these angles is found to be a function of the initial structural distortion in α-quartz homeotypes with the notable exception of α-quartz-type FePO4, which appears to be dynamically unstable. The stability of α-quartz and α-quartz-type germanium dioxide was investigated at high pressure by x-ray powder diffraction. New six-fold coordinated forms were found in both materials. The important, perovskite-type, piezoelectric material PbZr0.52Ti0.48O3was studied up to 18 GPa by angle-dispersive, x-ray diffraction using an imaging plate and by Raman spectroscopy. A novel phase transition was found in this system at close to 5 GPa. Whereas the x-ray diffraction data indicated no deviation from cubic symmetry above this pressure, a strong Raman signal was present in this phase, which is similar to those observed for ferroelectric relaxors.

Study of Kinetics of Solid Phase Transition in Tetracosane С24Н50 by High-Resolution Synchrotron X-Ray Powder Diffraction

2019 ◽  
Vol 61 (6) ◽  
pp. 1128-1135
Author(s):  
V. A. Marikhin ◽  
P. V. Dorovatovskii ◽  
Ya. V. Zubavichus ◽  
M. V. Baidakova ◽  
E. M. Ivan’kova ◽  
...  
Keyword(s):  
Phase Transition ◽  
High Resolution ◽  
Powder Diffraction ◽  
Solid Phase ◽  
X Ray ◽  
Solid Phase Transition ◽  
Kinetics Of

scholarly journals Investigation and Possibilities of Reuse of Carbon Dioxide Absorbent Used in Anesthesiology

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5052
Author(s):  
Bartłomiej Rogalewicz ◽  
Agnieszka Czylkowska ◽  
Piotr Anielak ◽  
Paweł Samulkiewicz
Keyword(s):  
Carbon Dioxide ◽  
Thermal Properties ◽  
Powder Diffraction ◽  
Soda Lime ◽  
Closed Circuit ◽  
Carbon Dioxide Absorption ◽  
X Ray ◽  
Kinetics Of ◽  
Carbon Dioxide Absorbent

Absorbents used in closed and semi-closed circuit environments play a key role in preventing carbon dioxide poisoning. Here we present an analysis of one of the most common carbon dioxide absorbents—soda lime. In the first step, we analyzed the composition of fresh and used samples. For this purpose, volumetric and photometric analyses were introduced. Thermal properties and decomposition patterns were also studied using thermogravimetric and X-ray powder diffraction (PXRD) analyses. We also investigated the kinetics of carbon dioxide absorption under conditions imitating a closed-circuit environment.

Kinetics of the lamellar-inverse hexagonal phase transition determined by time-resolved x-ray diffraction

Biochemistry ◽  
1992 ◽  
Vol 31 (4) ◽  
pp. 1081-1092 ◽  
Author(s):  
Mark W. Tate ◽  
Erramilli Shyamsunder ◽  
Sol M. Gruner ◽  
Kevin L. D'Amico
Keyword(s):  
Phase Transition ◽  
Hexagonal Phase ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Kinetics Of

scholarly journals The crystallographic phase transition for a ferric thiosemicarbazone spin crossover complex studied by X-ray powder diffraction

2006 ◽  
Vol 30 (11) ◽  
pp. 1621-1627 ◽  
Author(s):  
Sébastien Floquet ◽  
Nathalie Guillou ◽  
Philippe Négrier ◽  
Eric Rivière ◽  
Marie-Laure Boillot
Keyword(s):  
Phase Transition ◽  
Powder Diffraction ◽  
Spin Crossover ◽  
X Ray
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