Prediction of structural parameters and physical properties ofCsHSO3up to 60 GPa

1998 ◽  
Vol 57 (8) ◽  
pp. 4321-4326 ◽  
Author(s):  
C. Griewatsch ◽  
B. Winkler ◽  
V. Milman ◽  
C. J. Pickard
2020 ◽  
Vol 10 (1) ◽  
Author(s):  
R. Rodríguez-González ◽  
L. M. Gaggero-Sager ◽  
I. Rodríguez-Vargas

Abstract 2D materials open the possibility to study Dirac electrons in complex self-similar geometries. The two-dimensional nature of materials like graphene, silicene, phosphorene and transition-metal dichalcogenides allow the nanostructuration of complex geometries through metallic electrodes, interacting substrates, strain, etc. So far, the only 2D material that presents physical properties that directly reflect the characteristics of the complex geometries is monolayer graphene. In the present work, we show that silicene nanostructured in complex fashion also displays self-similar characteristics in physical properties. In particular, we find self-similar patterns in the conductance, spin polarization and thermoelectricity of Cantor-like silicene structures. These complex structures are generated by modulating electrostatically the silicene local bandgap in Cantor-like fashion along the structure. The charge carriers are described quantum relativistically by means of a Dirac-like Hamiltonian. The transfer matrix method, the Landauer–Büttiker formalism and the Cutler–Mott formula are used to obtain the transmission, transport and thermoelectric properties. We numerically derive scaling rules that connect appropriately the self-similar conductance, spin polarization and Seebeck coefficient patterns. The scaling rules are related to the structural parameters that define the Cantor-like structure such as the generation and length of the system as well as the height of the potential barriers. As far as we know this is the first time that a 2D material beyond monolayer graphene shows self-similar quantum transport as well as that transport related properties like spin polarization and thermoelectricity manifest self-similarity.


1990 ◽  
Vol 43 (12) ◽  
pp. 2035 ◽  
Author(s):  
PV Bernhardt ◽  
P Comba ◽  
LR Gahan ◽  
GA Lawrance

Reaction of the dicopper (II) complex of the binucleating ligand 5,5- bis (4-amino-2-azabutyl)-3,7-diazanonane-1,9-diamine with nitroethane and formaldehyde in water gives the respective macrobicyclic and macromonocyclic binucleating ligands 7,21-dimethyl-7,21-dinitro-2,5,9,12,16,19,23,26-octaazaspiro[13.13] heptacosane and 6,6-bis(4- amino-2-azabutyl)-13-methyl-13-nitro-1,4,8,11-tetraazacyclotetradecane , both as their dicopper (II) complexes. Similarly, condensation of the dicopper (II) complex of 5,5-bis(4-amino- 2-thiabutyl)-3,7-dithianonane-1,9-diamine with nitroethane and formaldehyde results in the binucleating macrobicycle 7,21-dimethyl- 7,21-dinitro-2,12,16,26-tetrathia-5,9,19,23-tetraazaspiro[13.13]-heptacosane. Physical properties of all complexes are reported and comparisons with mononuclear relatives are made. Structural parameters derived from electron paramagnetic resonance spectra are discussed.


1985 ◽  
Vol 63 (12) ◽  
pp. 3516-3520 ◽  
Author(s):  
W. Kliegel ◽  
H.-W. Motzkus ◽  
Steven J. Rettig ◽  
James Trotter

Details of the preparation and physical properties of (Me4N)+ (Ph4B3O3)− are given. Crystals of tetramethylammonium 2,4,6,6-tetraphenyl-1,3,5-trioxa-2,4-dibora-6-boratacyclohexane are orthorhombic, a = 18.130(2), b = 11.9745(7), c = 12.5187(5) Å, Z = 4, space group Pna21. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.056 and Rw = 0.064 for 1460 reflections with I ≥ 2σ(I). The crystal structure consists of discrete tetramethylammonium cations and tetraphenylboroxinate anions, the first such anion to be structurally characterized. The six-membered B3O3 ring is significantly non-planar, having a flattened O(1)-envelope conformation (maximum deviation from the mean plane = 0.074(4) Å for O(1)). The boroxine ring in the anion shows significant deviations from the D3h symmetry observed for neutral boroxines. Important mean structural parameters: B(sp3)—O = 1.494(2), B(sp2)—O[B(sp3)] = 1.320(9), B(sp2)—O[B(sp2)] = 1.389(3) Å, O—B(sp3)—O = 110.5(5), O—B(sp2)—O = 121.7(6), B(sp2)—O—B(sp2) = 118.9(5), and B(sp3)—O—B(sp2) = 122.9(1)°.


2017 ◽  
Vol 25 (0) ◽  
pp. 24-29
Author(s):  
Daiva Mikučioniené ◽  
Lina Čepukonė

Natural and man-made fibres of natural origin are more and more widely used, while consideration of sustainability is constantly increasing. The properties and processing behaviour of newly introduced fibres of natural origin are usually compared and often predicted on the basis of widely investigated fibres; however, this prediction sometimes does not have any confirmed basis. Structural parameters and the majority of mechanical and physical properties of knitted fabrics depend on technical characteristics of the knitting machine, on the properties of yarns as well as on the origin of the raw material. This study attempts to develop knits from new natural peat fibres and their combination with widely used woollen, cotton and elastomeric Lycra yarns and to investigate the influence of peat fibre’s nature on structural parameters such as loop length, wale and course spacing, area density, the tightness factor and on main physical properties such as dimensional stability, air permeability and water adsorption.


2019 ◽  
Vol 61 (4) ◽  
pp. 659
Author(s):  
Uttam Kumar Chowdhury ◽  
Tapas Chandra Saha

AbstractUsing ab initio technique the physical properties of ScIr_2 superconductor have been investigated with T _c 1.03 K with a MgCu_2-type structure. We have carried out the plane-wave pseudopotential approach within the framework of the first-principles density functional theory (DFT) implemented within the CASTEP code. The calculated structural parameters confirm a good agreement with the experimental and other theoretical results. Using the Voigt-Reuss-Hill (VRH) averaging scheme the most important elastic properties including the bulk modulus B, shear modulus G , Young’s modulus E and Poisson’s ratio ν of ScIr_2 are determined. At ambient condition, the values of Cauchy pressure and Pugh’s ratio exhibit ductile nature of ScIr_2. The electronic and optical properties of ScIr_2 were investigated for the first time. The electronic band structure reveals metallic conductivity and the major contribution comes from Ir-5 d states. In the ultraviolet region the reflectivity is high up to 50 eV as evident from the reflectivity spectrum.


2018 ◽  
Vol 26 (4(130)) ◽  
pp. 59-66
Author(s):  
Erhan Kenan Çeven ◽  
Gizem Karakan Günaydin

Recently there have been new trends in fancy yarns in order to meet consumer demands for drapery, decorative and outwear fabrics. Macaroni yarns are a promising group of fancy yarn which allows new yarn designs with different raw materials at different yarn counts. In the study, supreme knitted fabrics were produced with macaroni yarns of different raw materials (polyester, acyclic, cotton) at different yarn counts (Nm 2/1, Nm 2.5/1, Nm 3.3/1, Nm 4/1 and Nm 4.5/1). Completely randomised one-factor analysis of variance (ANOVA) was used for determination of the statistical significance of the fabric type on selected physical properties of knitted macaroni fabrics in terms of fabric weight (g/m2), dimensional change (%) in the wale and course direction, abrasion resistance, and air permeability properties before and after the washing process. According to the results of the statistical analyses performed using the experimental values obtained from the tests, we determined that the fabric weights (g/m2), dimensional changes (%) in the wale and course direction, abrasion resistance and air permeability properties before and after washing were significantly influenced by the macaroni yarn’s structural parameters (such as the yarn count and raw material comprising it).


1998 ◽  
Vol 26 ◽  
pp. 45-50 ◽  
Author(s):  
Vladimir N. Golubev ◽  
Anatoly D. Frolov

The regular packing of spheres or polyhedrons of various shapes linked by rigid bonds is presented and discussed as a model of snow structure. Basic structural parameters of this model are: the coordination number and introduced dimensionless factors of friability and rigidity. The snow densification is described as successive changes of these parameters. Use of the model allows us to relate the density increase from ~130 to ~320, ~550, ~700, ~820 and 917 kg m−3, while the coordination number of the structure increases accordingly from 3 (friable hexagonal) to 4 (tetrahedral), 6 (cubic), 8, 10, 12 (dense hexagonal). These structural changes are in good agreement with the critical densities established in experimental studies of snow densification and the physical properties of snow. It is shown that the model presented allows us to estimate the mechanical properties of ice-porous media: Young’s modulus, Poisson’s ratio and strength.


1990 ◽  
Vol 25 (6) ◽  
pp. 481-488 ◽  
Author(s):  
K. Guergouri ◽  
Y. Marfaing ◽  
R. Triboulet ◽  
A. Tromson-Carli

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