scholarly journals Molecular simulation of low temperature argon adsorption in several models of IRMOF-1 with defects and structural disorder

2016 ◽  
Vol 45 (10) ◽  
pp. 4203-4212 ◽  
Author(s):  
L. Sarkisov
Keyword(s):  
Low Temperature ◽  
Molecular Simulation ◽  
Conceptual Models ◽  
Structural Disorder ◽  
Argon Adsorption

Low temperature adsorption of argon in several conceptual models of IRMOF-1 featuring various types of defects and inclusions has been investigated.

scholarly journals Ultra-low temperature structure determination of a Mn12 single-molecule magnet and the interplay between lattice solvent and structural disorder

CrystEngComm ◽  
2013 ◽  
Vol 15 (17) ◽  
pp. 3423 ◽  
Author(s):  
Andrew R. Farrell ◽  
Jonathan A. Coome ◽  
Michael R. Probert ◽  
Andrès E. Goeta ◽  
Judith A. K. Howard ◽  
...  
Keyword(s):  
Low Temperature ◽  
Single Molecule ◽  
Structure Determination ◽  
Structural Disorder ◽  
Temperature Structure ◽  
Single Molecule Magnet

scholarly journals Carrier concentration dependence of structural disorder in thermoelectric Sn1−xTe

IUCrJ ◽  
2016 ◽  
Vol 3 (5) ◽  
pp. 377-388 ◽  
Author(s):  
Mattia Sist ◽  
Ellen Marie Jensen Hedegaard ◽  
Sebastian Christensen ◽  
Niels Bindzus ◽  
Karl Frederik Færch Fischer ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Low Temperature ◽  
Rock Salt ◽  
Theoretical Calculations ◽  
Rhombohedral Phase ◽  
Structural Disorder ◽  
Entropy Method ◽  
Salt Crystal ◽  
X Ray ◽  
Two Samples

SnTe is a promising thermoelectric and topological insulator material. Here, the presumably simple rock salt crystal structure of SnTe is studied comprehensively by means of high-resolution synchrotron single-crystal and powder X-ray diffraction from 20 to 800 K. Two samples with different carrier concentrations (sampleA= high, sampleB= low) have remarkably different atomic displacement parameters, especially at low temperatures. Both samples contain significant numbers of cation vacancies (1–2%) and ordering of Sn vacancies possibly occurs on warming, as corroborated by the appearance of multiple phases and strain above 400 K. The possible presence of disorder and anharmonicity is investigated in view of the low thermal conductivity of SnTe. Refinement of anharmonic Gram–Charlier parameters reveals marginal anharmonicity for sampleA, whereas sampleBexhibits anharmonic effects even at low temperature. For both samples, no indications are found of a low-temperature rhombohedral phase. Maximum entropy method (MEM) calculations are carried out, including nuclear-weighted X-ray MEM calculations (NXMEM). The atomic electron densities are spherical for sampleA, whereas for sampleBthe Te electron density is elongated along the 〈100〉 direction, with the maximum being displaced from the lattice position at higher temperatures. Overall, the crystal structure of SnTe is found to be defective and sample-dependent, and therefore theoretical calculations of perfect rock salt structures are not expected to predict the properties of real materials.

Magnetic properties of uniform γ–Fe2O3 nanoparticles smaller than 5 nm prepared by laser pyrolysis

1999 ◽  
Vol 14 (7) ◽  
pp. 3066-3072 ◽  
Author(s):  
M. P. Morales ◽  
S. Veintemillas-Verdaguer ◽  
C. J. Serna
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Low Temperature ◽  
Structural Disorder ◽  
Iron Pentacarbonyl ◽  
Spherical Particles ◽  
Fe2o3 Nanoparticles ◽  
Laser Pyrolysis ◽  
Preparation Conditions ◽  
Very High

γ–Fe2O3 spherical particles with diameters between 5 and 3.5 nm—very uniform in size—have been prepared by laser pyrolysis of iron pentacarbonyl. The infrared spectra of the samples showed features that indicated different degrees of crystallinity according to the preparation conditions. Low saturation magnetization values (≈10 emu/g) and very high coercivities at low temperature (3000 Oe) have been found for the γ–Fe2O3 nanoparticles with the smaller particle size and the highest structural disorder. To explain the magnetic properties, it was necessary to consider additional anisotropies caused by the increase in surface and structural disorder as the particle size decreased.

Conceptual models for partially premixed low-temperature diesel combustion

2013 ◽  
Vol 39 (2-3) ◽  
pp. 246-283 ◽  
Author(s):  
Mark P.B. Musculus ◽  
Paul C. Miles ◽  
Lyle M. Pickett
Keyword(s):  
Low Temperature ◽  
Conceptual Models ◽  
Diesel Combustion ◽  
Partially Premixed
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