The Ammonia-Driven Phase Transition in Bulk and Nanostructured Potassium Graphite KC24

2009 ◽  
Vol 1216 ◽  
Author(s):  
Arthur Lovell ◽  
Zeynep Kurban ◽  
Stephen M. Bennington ◽  
Gadipelli Srinivas ◽  
Neal T. Skipper ◽  
...  
Keyword(s):  
Phase Transition ◽  
Interlayer Spacing ◽  
Hydrogen Uptake ◽  
Bulk Sample ◽  
Nanostructured Material ◽  
Exfoliated Graphite ◽  
Time Resolved ◽  
Graphite Nanofibers ◽  
Modulated Phase ◽  
Low Crystalline

AbstractWe report the synthesis of nanostructured stage-2 potassium graphite, KC24, by intercalation of turbostratic graphite nanofibers produced from an electrospun polymer, and compare its properties with exfoliated graphite-based KC24. The nanostructured KC24 sample has low crystalline order and slightly increased interlayer spacing of 8.76 Å, compared with 8.65 Å in the bulk sample, indicating minimal registration of the graphite planes. Time-resolved time-of-flight neutron diffraction on both nanostructured and bulk KC24 under ammoniation is suggestive of a more homogeneous and faster pressure-modulated phase transition to the ternary ammoniated potassium-graphite in the nanostructured material. Following ammoniation, negligible hydrogen uptake is observed at 50 K.

100 ps time-resolved crystallographic investigation of the photoinduced phase transition in TFF-CA

2004 ◽  
Vol 114 ◽  
pp. 99-101
Author(s):  
L. Guérin ◽  
E. Collet ◽  
M. Buron-Le Cointe ◽  
M.-H. Lemée-Cailleau ◽  
H. Cailleau ◽  
...  
Keyword(s):  
Phase Transition ◽  
Crystallographic Investigation ◽  
Time Resolved

Pulsed Microwave Processing of High-TC Superconducting Films

1992 ◽  
Vol 269 ◽  
Author(s):  
R. B. James ◽  
R. A. Alvarez ◽  
A. K. Stamper ◽  
X. J. Bao ◽  
T. E. Schlesinger ◽  
...  
Keyword(s):  
Phase Transition ◽  
Barium Copper Oxide ◽  
Precursor Film ◽  
Silicon Substrates ◽  
Molten Layer ◽  
Time Resolved ◽  
Barium Copper ◽  
In Situ Experiments ◽  
Yttrium Barium

ABSTRACTWe have used 2.0-μsec microwave pulses at a frequency of 2.856 GHz to rapidly heat thin amorphous yttrium-barium-copper-oxide (YBCO) films deposited onto silicon substrates. The samples were irradiated inside a WR-284 waveguide by single-pass TE10 pulses in a traveling wave geometry. X-ray diffractometry studies show that an amorphous-to-crystalline phase transition occurs for incident pulse powers exceeding about 6 MW, in which case the amorphous YBCO layer is converted to Y2BaCuO5. Microscopy of the irradiated film reveals that the phase transition is brought about by melting of the YBCO precursor film and crystallization of the molten layer upon solidification. Time-resolved in situ experiments of the microwave reflectivity (R) and transmissivity (T) show that there is an abrupt change in R for microwave pulse powers exceeding the melt threshold, so that measurements of R and T can be used to monitor the onset of surface melting.

Interaction of human serum albumin with liposomes of saturated and unsaturated lipids with different phase transition temperatures: a spectroscopic investigation by membrane probe PRODAN

RSC Advances ◽  
2014 ◽  
Vol 4 (28) ◽  
pp. 14335-14347 ◽  
Author(s):  
Raina Thakur ◽  
Anupam Das ◽  
Anjan Chakraborty
Keyword(s):  
Phase Transition ◽  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Spectroscopic Techniques ◽  
Time Resolved Fluorescence ◽  
Time Resolved ◽  
Unsaturated Lipids ◽  
Membrane Probe ◽  
Phase Transition Temperatures

The interaction of human serum albumin (HSA) with liposomes made of saturated and unsaturated phosphocholines has been studied using circular dichroism (CD), steady state and time resolved fluorescence spectroscopic techniques.

Parameterization of the coupling between strain and order parameter for LuF[SeO3]

2014 ◽  
Vol 47 (2) ◽  
pp. 701-711 ◽  
Author(s):  
Oxana V. Magdysyuk ◽  
Melanie Müller ◽  
Robert E. Dinnebier ◽  
Christian Lipp ◽  
Thomas Schleid
Keyword(s):  
Phase Transition ◽  
Order Parameter ◽  
Structural Phase ◽  
High Temperature Phase ◽  
Temperature Phase ◽  
Time Resolved ◽  
Synchrotron Powder Diffraction ◽  
First Order Phase Transition ◽  
Temperature Phase Transition ◽  
First Order Phase

The high-temperature phase transition of LuF[SeO3] has been characterized by time-resolved high-resolution synchrotron powder diffraction. On heating, a second-order structural phase transition was found at 393 K, while on cooling the same phase transition occurs at 371 K, showing a large hysteresis typical for a first-order phase transition. Detailed analysis using sequential and parametric whole powder pattern fitting revealed that the coupling between the strain and the displacive order parameter determines the behaviour of the material during the phase transition. Different possible coupling mechanisms have been evaluated and the most probable rationalized.

scholarly journals In Situ Time-Resolved Decomposition of β-Hydride Phase in Palladium Nanoparticles Coated with Metal-Organic Framework

Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 810
Author(s):  
Mikhail V. Kirichkov ◽  
Aram L. Bugaev ◽  
Alina A. Skorynina ◽  
Vera V. Butova ◽  
Andriy P. Budnyk ◽  
...  
Keyword(s):  
Phase Transition ◽  
Particle Size ◽  
Hydrogen Adsorption ◽  
Metal Organic Framework ◽  
Pd Nanoparticles ◽  
Time Resolved ◽  
Metal Organic ◽  
Hydride Phases ◽  
Organic Framework

The formation of palladium hydrides is a well-known phenomenon, observed for both bulk and nanosized samples. The kinetics of hydrogen adsorption/desorption strongly depends on the particle size and shape, as well as the type of support and/or coating of the particles. In addition, the structural properties of hydride phases and their distribution also depend on the particle size. In this work, we report on the in situ characterization of palladium nanocubes coated with HKUST-1 metal-organic framework (Pd@HKUST-1) during desorption of hydrogen by means of synchrotron-based time-resolved X-ray powder diffraction. A slower hydrogen desorption, compared to smaller sized Pd nanoparticles was observed. Rietveld refinement of the time-resolved data revealed the remarkable stability of the lattice parameters of α- and β-hydride phases of palladium during the α- to β- phase transition, denoting the behavior more similar to the bulk materials than nanoparticles. The stability in the crystal sizes for both α- and β-hydride phases during the phase transition indicates that no sub-domains are formed within a single particle during the phase transition.

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
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