scholarly journals AVALIAÇÃO DA ESTRUTURA ELETRÔNICA DA FASE MONOCLINICA DO ÓXIDO DE NIÓBIO COM BASE NO USO DE DIFERENTES FUNCIONAIS DE DENSIDADE

Química Nova ◽  
2021 ◽  
Author(s):  
Kamila Ody ◽  
João Jesus ◽  
Carlos Cava ◽  
Anderson Albuquerque ◽  
Ary Maia ◽  
...  
Keyword(s):  
Density Functional ◽  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Density Functionals ◽  
Monoclinic Structure ◽  
Functional Theory ◽  
Periodic Models ◽  
Physical And Chemical ◽  
And Chemical Properties

ASSESSMENT OF THE ELECTRONIC STRUCTURE OF THE MONOCLINIC PHASE OF NIOBIUM OXIDE BASED ON THE USE OF DIFFERENT DENSITY FUNCTIONALS. Niobium oxides, Nb2O5, are considered semiconductor materials with very attractive physical and chemical properties for applications in many areas, such as catalysis, sensors, medical, aerospace, etc. Especially, the characterization of Nb2O5-based nanostructures with monoclinic structure has received much attention in recent years. However, despite the great importance of this system, some of its fundamentals properties are still not fully understood. Hence, this work aims to apply the theoretical methodologies through Density Functional Theory (DFT) calculations in periodic models based on the use of different density functionals (like B1WC, B3PW, B3LYP, PBE0, PBESOL0, SOGGAXC, and WC1LYP) to investigate the physical and chemical properties of the monoclinic structure of Nb2O5. The band structures, energy bandgap, density of state, and vibrational properties, as well as order-disorder effects on the monoclinic structure of Nb2O5 are investigated in this study. Our theoretical results show a better agreement with experimental data for the B3LYP functional and hence lead to new perspectives on the deeper physicochemical understanding of the monoclinic Nb2O5. From these computational tools, it is possible to unravel the relations between structure and properties, which may contribute to the future development of new devices and applications based on these materials.

Evolution of the structural, energetic, and electronic properties of the 3d, 4d, and 5d transition-metal clusters (30 TMn systems for n = 2–15): a density functional theory investigation

2017 ◽  
Vol 19 (23) ◽  
pp. 15484-15502 ◽  
Author(s):  
Anderson S. Chaves ◽  
Maurício J. Piotrowski ◽  
Juarez L. F. Da Silva
Keyword(s):  
Density Functional Theory ◽  
Transition Metal ◽  
Density Functional ◽  
Metal Clusters ◽  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Transition Metal Clusters ◽  
Functional Theory ◽  
Physical And Chemical ◽  
And Chemical Properties

Subnanometric transition-metal (TM) clusters have attracted great attention due to their unexpected physical and chemical properties, leastwise compared to their bulk counterparts.

scholarly journals Physical and chemical properties of Cu(i) compounds with O and/or H

2017 ◽  
Vol 46 (2) ◽  
pp. 529-538 ◽  
Author(s):  
Yunguo Li ◽  
Pavel A. Korzhavyi
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Ab Initio ◽  
Chemical Bonding ◽  
Density Functional ◽  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Functional Theory ◽  
Physical And Chemical ◽  
And Chemical Properties

The electronic structure and chemical bonding of Cu(i) compounds with O and/or H are investigated using ab initio calculations based on density functional theory.

ZnO/ZnS (hetero)structures: ab initio investigations of polytypic behavior of mixed ZnO and ZnS compounds

2018 ◽  
Vol 74 (6) ◽  
pp. 628-642 ◽  
Author(s):  
Dejan Zagorac ◽  
Jelena Zagorac ◽  
J. Christian Schön ◽  
Nemanja Stojanović ◽  
Branko Matović
Keyword(s):  
Ab Initio ◽  
Density Functional ◽  
Local Density ◽  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Density Approximation ◽  
New Materials ◽  
Functional Theory ◽  
Physical And Chemical ◽  
And Chemical Properties

The range of feasible ZnO/ZnS polytypes has been explored, predicting alternative structural arrangements compared with previously suggested or observed structural forms of ZnO/ZnS compounds, including bulk crystal structures, various nanostructures, heterostructures and heterojunctions. All calculations were performed ab initio using density functional theory–local density approximation and hybrid Heyd–Scuseria–Ernzerhof functionals. Specifically, pure ZnO and ZnS compounds and mixed ZnO1–x S x compounds (x = 0.20, 0.25, 0.33, 0.50, 0.60, 0.66 and 0.75) are investigated and a multitude of possible stable polytypes for ZnO/ZnS compounds creating new possibilities for synthesis of new materials with improved physical and chemical properties are identified.

scholarly journals Characterization of gelatins from Nile tilapia skins preserved by freezing and salting

2019 ◽  
Vol 40 (6) ◽  
pp. 2581
Author(s):  
Adriana Cristina Bordignon ◽  
Maria Luiza Rodrigues de Souza ◽  
Eliane Gasparino ◽  
Edson Minoru Yajima ◽  
Jesuí Vergílio Visentainer ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Nile Tilapia ◽  
Saturated Fatty Acids ◽  
Chemical Properties ◽  
Monounsaturated Fatty Acids ◽  
Gel Strength ◽  
Physical And Chemical Properties ◽  
Physical And Chemical ◽  
And Chemical Properties

After Nile tilapia skin was preserved using the methods of freezing and dry salting, characteristics of skin gelatin were evaluated with regard to yield, rheological features and physical and chemical properties. Preservation was performed after filleting, at which time skins were either frozen (-18°C) for 7 days or salted (25°C) for 7 days. Although no differences (p > 0.05) were observed with respect to humidity, protein, lipid, ash and calcium levels, gelatin from salted skins had a higher concentration of iron relative to frozen skins. Further, twenty-three fatty acids were detected in salted skins compared with merely three found in skin derived gelatin. Of amino acids found, glycine, alanine, proline and arginine were the most abundant. Hydroxyproline abundance in salted and frozen skin gelatin were 8.76% and 8.71%, respectively. In addition, salted skin gelatins had a greater accumulation of saturated fatty acids and lower rates of monounsaturated fatty acids. Salted skin gelatin had the highest yield (18g × 100g-1), gel strength (200 g) and viscosity (19.02mPas) when compared to the yield (17g × 100g-1), gel strength (12.7g) and viscosity (9.16 mPas) of frozen skins. Results show that gelatin from dry salted skin had the best yield and also had relatively better rheological properties, more iron, and better coloration relative to gelatin obtained from frozen skins of Nile tilapia.

Extraction and characterization of the blue-sensitive visual pigment of the toad Bufo marinus

1987 ◽  
Vol 65 (4) ◽  
pp. 884-887 ◽  
Author(s):  
A. J. Sillman
Keyword(s):  
Vitamin A ◽  
Visual Pigment ◽  
Chemical Properties ◽  
Bufo Marinus ◽  
Physical And Chemical Properties ◽  
Electrophysiological Studies ◽  
Physical And Chemical ◽  
Toad Bufo ◽  
And Chemical Properties

The blue-sensitive visual pigment of the green rods of Bufo marinus was extracted with digitonin. The pigment is present in an amount equal to about 11% that of rhodopsin. It is based on vitamin A1 and exhibits a maximum absorbance of 433 nm. The pigment is labile and readily destroyed by hydroxylamine, regenerates to a much greater degree than does rhodopsin, and is more effectively extracted from the membrane than is rhodopsin. The green rod pigment of Bufo marinus appears to share the same physical and chemical properties as the green rod pigments of other amphibians. Therefore, the results of electrophysiological studies on the green rods of Bufo marinus can be more confidently generalized to other species. The results are discussed in terms of the blue phototaxis that is characteristic of many amphibians.

Physicochemical characterization of nanoparticles and their behavior in the biological environment

2014 ◽  
Vol 16 (29) ◽  
pp. 15053-15067 ◽  
Author(s):  
L. Treuel ◽  
K. A. Eslahian ◽  
D. Docter ◽  
T. Lang ◽  
R. Zellner ◽  
...  
Keyword(s):  
Physicochemical Characterization ◽  
Chemical Properties ◽  
Sufficient Accuracy ◽  
Physical And Chemical Properties ◽  
Solvent Phase ◽  
Biological Environment ◽  
Physical And Chemical ◽  
And Chemical Properties

Whilst the physical and chemical properties of nanoparticles in the gas or idealized solvent phase can nowadays be characterized with sufficient accuracy, this is no longer the case for particles in the presence of a complex biological environment.

Sign in / Sign up

Export Citation Format

Share Document