scholarly journals Defect structure in δ-Bi5PbY2O11.5

RSC Advances ◽  
2019 ◽  
Vol 9 (17) ◽  
pp. 9640-9653 ◽  
Author(s):  
Anna Borowska-Centkowska ◽  
Xi Liu ◽  
Marcin Krynski ◽  
Marzena Leszczynska ◽  
Wojciech Wrobel ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Ab Initio ◽  
Defect Structure ◽  
Md Simulations ◽  
Total Neutron ◽  
Vacancy Ordering ◽  
And Migration ◽  
Migration Pathways ◽  
Oxide Ion

Total neutron scattering analysis and ab initio MD simulations reveal details of oxide ion vacancy ordering and migration pathways.

scholarly journals Oxide ion distribution, vacancy ordering and electrical behaviour in the Bi3NbO7–Bi3YbO6 pseudo-binary system

2014 ◽  
Vol 2 (43) ◽  
pp. 18624-18634 ◽  
Author(s):  
M. Leszczynska ◽  
X. Liu ◽  
W. Wrobel ◽  
M. Malys ◽  
J. R. Dygas ◽  
...  
Keyword(s):  
Binary System ◽  
Neutron Scattering ◽  
Total Neutron ◽  
Electrical Behaviour ◽  
Ion Distribution ◽  
Vacancy Ordering ◽  
System P ◽  
Vacancy Distribution ◽  
Cation Coordination ◽  
Oxide Ion

Total neutron scattering analysis reveals details of cation coordination and vacancy distribution in Bi3Nb1−xYbxO7−x.

The atomistic structure of yttria stabilised zirconia at 6.7 mol%: an ab initio study

2016 ◽  
Vol 18 (45) ◽  
pp. 31277-31285 ◽  
Author(s):  
Michael A. Parkes ◽  
David A. Tompsett ◽  
Mayeul d'Avezac ◽  
Gregory J. Offer ◽  
Nigel P. Brandon ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Ab Initio ◽  
Defect Structure ◽  
Low Energy ◽  
Ab Initio Study ◽  
Large Database ◽  
Ion Conductor ◽  
Oxide Ion Conductor ◽  
Oxide Ion ◽  
Atomistic Structure

GGA-DFT calculations performed on a large database of 6.7 mol% YSZ structures are compared to previous studies revealing a new low energy defect structure for this important oxide ion conductor.

scholarly journals Invasive Plant Species Distribution Is Structured by Soil and Habitat Type in the City Landscape

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 773
Author(s):  
Ilona Szumańska ◽  
Sandra Lubińska-Mielińska ◽  
Dariusz Kamiński ◽  
Lucjan Rutkowski ◽  
Andrzej Nienartowicz ◽  
...  
Keyword(s):  
Distribution Pattern ◽  
Species Distribution ◽  
Human Activities ◽  
Invasive Plant ◽  
Habitat Type ◽  
Permanent Plots ◽  
Human Land Use ◽  
And Migration ◽  
Migration Pathways ◽  
The City

Invasive alien species (IAS) is a global problem that largely relates to human activities and human settlements. To prevent the further spread of IAS, we first need to know their pattern of distribution, to determine which constitutes the greatest threat, and understand which habitats and migration pathways they prefer. Our research aimed to identify the main vectors and distribution pattern of IAS of plants in the city environment. We checked the relations between species distribution and such environmental factors as urban soil type and habitat type. We applied data on IAS occurrence (collected in the period 1973–2015) in 515 permanent plots with dimensions of 0.5 × 0.5 km and analyzed by direct ordination methods. In total, we recorded 66 IAS. We found a 27% variance in the IAS distribution pattern, which can be explained by statistically significant soil and habitat types. The most important for species distribution were: river and alluvial soils, forests and related rusty soils, and places of intensive human activities, including areas of urbisols and industriosols. Our results provide details that can inform local efforts for the management and control of invasive species, and they provide evidence of the different associations between natural patterns and human land use.

scholarly journals Ab Initio Investigation of Helium Mobility in La2Zr2O7 Pyrochlore

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 667
Author(s):  
Yanxia Lu ◽  
Qing Peng ◽  
Chenguang Liu
Keyword(s):  
Nuclear Waste ◽  
Density Functional ◽  
Minimum Energy ◽  
Elastic Band ◽  
Waste Forms ◽  
Band Method ◽  
And Migration ◽  
High Level ◽  
Migration Pathways ◽  
Nuclear Waste Forms

The α-decay of incorporated actinides continuously produces helium, resulting in helium accumulation and causing security concerns for nuclear waste forms. The helium mobility is a key issue affecting the accumulation and kinetics of helium. The energy barriers and migration pathways of helium in a potential high-level nuclear waste forms, La2Zr2O7 pyrochlore, have been investigated in this work using the climbing image nudged elastic band method with density functional theory. The minimum energy pathway for helium to migrate in La2Zr2O7 is identified as via La–La interstitial sites with a barrier of 0.46 eV. This work may offer a theoretical foundation for further prospective studies of nuclear waste forms.

scholarly journals Bulk and Confined Benzene-Cyclohexane Mixtures Studied by an Integrated Total Neutron Scattering and NMR Method

2021 ◽  
Author(s):  
Terri-Louise Hughes ◽  
Marta Falkowska ◽  
Markus Leutzsch ◽  
Andrew J. Sederman ◽  
Mick D. Mantle ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Structure Refinement ◽  
Computational Simulation ◽  
Liquid Mixtures ◽  
Coordination Shell ◽  
Bulk Liquid ◽  
Total Neutron ◽  
Time Resolved ◽  
Sample Composition ◽  
Potential Structure

AbstractHerein mixtures of cyclohexane and benzene have been investigated in both the bulk liquid phase and when confined in MCM-41 mesopores. The bulk mixtures have been studied using total neutron scattering (TNS), and the confined mixtures have been studied by a new flow-utilising, integrated TNS and NMR system (Flow NeuNMR), all systems have been analysed using empirical potential structure refinement (EPSR). The Flow NeuNMR setup provided precise time-resolved chemical sample composition through NMR, overcoming the difficulties of ensuring compositional consistency for computational simulation of data ordinarily found in TNS experiments of changing chemical composition—such as chemical reactions. Unique to the liquid mixtures, perpendicularly oriented benzene molecules have been found at short distances from the cyclohexane rings in the regions perpendicular to the carbon–carbon bonds. Upon confinement of the hydrocarbon mixtures, a stronger parallel orientational preference of unlike molecular dimers, at short distances, has been found. At longer first coordination shell distances, the like benzene molecular spatial organisation within the mixture has also found to be altered upon confinement.

Sign in / Sign up

Export Citation Format

Share Document