3,492 research outputs found
A Cluster-Based Computational Thermodynamics Framework with Intrinsic Chemical Short-Range Order: Part I. Configurational Contribution
Exploiting chemical short-range order (SRO) is a promising new avenue for
manipulating the properties of alloys. However, existing modeling frameworks
are not sufficient to understand and predict SRO in multicomponent (>3) alloys.
In this work, we developed a hybrid computational thermodynamics framework by
marrying unique advantages from CVM (Cluster Variation Method) and CALPHAD
(CALculation of PHAse Diagram) method through incorporating chemical SRO into
CALPHAD with a novel cluster-based solution model. The key is to use the
Fowler-Yang-Li transform to decompose the cumbersome cluster chemical
potentials in CVM into fewer site chemical potentials of the basis cluster,
thereby considerably reducing the number of variables that must be minimized
for multicomponent systems. The new framework puts more physics, primarily
intrinsic SRO, into CALPHAD, while maintaining its practicality and efficiency.
It leverages statistical mechanics to yield a more physical description of
configurational entropy and opens the door to cluster-based CALPHAD database
development. The application of this newly proposed model in the prototype FCC
AB system demonstrated that this model can correctly capture the essential
features of the phase diagram and thermodynamic properties. The hybrid
CVM-CALPHAD framework represents a new methodology for thermodynamic modeling
that enables atomic-scale order to be exploited as a dimension for materials
design, which potentially leads to novel complex concentrated alloys. It
achieves a balance between the accuracy and computational cost for modeling
multicomponent alloys with the intrinsic SRO in the context of CALPHAD
Design of ultra-high temperature ceramics for oxidation resistance
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2-Methylsulfanyl-4-(3-pyridyl)pyrimidine
In the title compound, C10H9N3S, the dihedral angle between the aromatic rings is 8.09 (14)°. In the crystal, a C—H⋯N interaction links the molecules, forming chains
High Entropy Rare Earth Oxide (HERO) Environmental Barrier Coatings for Refractory Metal Alloys
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2-Methyl-4-nitrophenol
The molecule of the title compound, C7H7NO3, is nearly planar [maximum deviation 0.112 (3) Å for one of the notro O atoms]. In the crystal structure, intermolecular O—H⋯O and C—H⋯O interactions link the molecules into a three-dimensional network
PandA(Box) flies on Bluesky: maintainable and user-friendly fly scans with Mamba at HEPS
At the High Energy Photon Source (HEPS), the upper-level control system for
PandABox has been ported to Bluesky, enabling the combination of both
components' flexibility in fly-scan applications. In less than 600 lines of
easily customisable and extensible backend code, provided are full control of
PandABox's TCP server in native ophyd, automated configuration (also including
wiring) of "PandA blocks" for constant-speed mapping experiments of various
dimensions, as well as generation of scans deliberately fragmented to deal with
hardware limits in numbers of exposure frames or sequencer table entries. Based
on this backend, a user-friendly Mamba frontend is developed for X-ray
fluorescence (XRF) mapping experiments, which provides fully online visual
feedback.Comment: 11 pages, 10 figures, submitted to Appl. Sc
Adsorption-controlled growth of La-doped BaSnO3 by molecular-beam epitaxy
Epitaxial La doped BaSnO3 films were grown in an adsorption controlled regime
by molecular beam epitaxy, where the excess volatile SnOx desorbs from the film
surface. A film grown on a (001) DyScO3 substrate exhibited a mobility of 183
cm^2 V^-1 s^-1 at room temperature and 400 cm^2 V^-1 s^-1 at 10 K, despite the
high concentration (1.2x10^11 cm^-2) of threading dislocations present. In
comparison to other reports, we observe a much lower concentration of (BaO)2
Ruddlesden Popper crystallographic shear faults. This suggests that in addition
to threading dislocations that other defects possibly (BaO)2 crystallographic
shear defects or point defects significantly reduce the electron mobility
2-Fluoro-N′-(2-hydroxybenzylidene)benzohydrazide
In the title compound, C14H11FN2O2, an intramolecular O—H⋯N hydrogen bond influences the molecular conformation; the two benzene rings form a dihedral angle of 18.4 (3)°. The F atom is disordered over two positions in a 0.717 (5):0.283 (5) ratio. In the crystal, intermolecular N—H⋯O hydrogen bonds link the molecules into chains extending along the c axis
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