Formation of a very high-density amorphous phase of carbon and its crystallization into a simple cubic structure at high pressure

2021 ◽  
Vol 200 ◽  
pp. 110822
Author(s):  
Murat Durandurdu
Keyword(s):  
High Pressure ◽  
Amorphous Phase ◽  
High Density ◽  
Simple Cubic ◽  
Cubic Structure ◽  
Very High

High-density amorphous phase of silicon carbide obtained under large plastic shear and high pressure

2012 ◽  
Vol 85 (5) ◽  
Author(s):  
Valery I. Levitas ◽  
Yanzhang Ma ◽  
Emre Selvi ◽  
Jianzhe Wu ◽  
John A. Patten
Keyword(s):  
Silicon Carbide ◽  
High Pressure ◽  
Amorphous Phase ◽  
High Density ◽  
Plastic Shear

Structural Systematics of the High-Pressure Phases of Phosphorus, Arsenic, Antimony and Bismuth

1997 ◽  
Vol 53 (3) ◽  
pp. 353-357 ◽  
Author(s):  
H. Iwasaki ◽  
T. Kikegawa
Keyword(s):  
High Pressure ◽  
Structure Data ◽  
Layered Structure ◽  
Structural Transition ◽  
Atomic Plane ◽  
Body Centered Cubic ◽  
Monoclinic Structure ◽  
Transition Sequence ◽  
Simple Cubic ◽  
Cubic Structure

New structural systematics of the high-pressure phases of the title elements are given on the basis of the results obtained in our diffraction studies and the results from the literature. Although the structural transition sequence with increasing pressure appears to be different for the four elements, reinterpretation of the structure data has shown that it is expressed in a systematic way as follows P A17–A7–PSC As A7–PSC–dist. BCC–BCC Sb A7–dist. BCC–BCC Bi A7–dist. PSC–dist. BCC–BCC. Notations used are A17 (orthorhombic layered structure), A7 (rhombohedral layered structure), PSC (primitive simple cubic structure), dist. PSC (monoclinic structure which is regarded as a distorted PSC), BCC (body-centered cubic structure) and dist. BCC (tetragonal structure which is regarded as a distorted BCC). Phosphorus lacks the post-PSC phases, but it is likely that the same transition sequence as that of arsenic is seen under extremely high pressure. Discussion is made on how the network of the densest atomic plane changes through the structural transition sequence.

scholarly journals Evidence for high-density liquid water between 0.1 and 0.3 GPa near 150 K

2019 ◽  
Vol 116 (19) ◽  
pp. 9191-9196 ◽  
Author(s):  
Josef N. Stern ◽  
Markus Seidl-Nigsch ◽  
Thomas Loerting
Keyword(s):  
Thermal Stability ◽  
High Pressure ◽  
Liquid Water ◽  
Crystallization Temperature ◽  
Amorphous Matrix ◽  
High Density ◽  
Amorphous Ice ◽  
Pressure Limit ◽  
Amorphous Ices ◽  
Very High

Thermal stability against crystallization upon isobaric heating at pressure 0.1 ≤ P ≤ 1.9 GPa is compared for five variants of high- (HDA) and very high-density amorphous ice (VHDA) with different preparation history. At 0.1–0.3 GPa expanded HDA (eHDA) and VHDA reach the same state before crystallization, which we infer to be the contested high-density liquid (HDL). Thus, 0.3 GPa sets the high-pressure limit for the possibility to observe HDL for timescales of minutes, hours, and longer. At P > 0.3 GPa the annealed amorphous ices no longer reach the same state before crystallization. Further examination of the results demonstrates that crystallization times are significantly affected both by the density of the amorphous matrix at the crystallization temperature Tx as well as by nanocrystalline domains remaining in unannealed HDA (uHDA) as a consequence of incomplete pressure-induced amorphization.

Nitroethane at high density: an experimental and computational vibrational study

2021 ◽  
Vol 23 (15) ◽  
pp. 9325-9336
Author(s):  
Akio Yoshinaka ◽  
Serge Desgreniers ◽  
Anguang Hu
Keyword(s):  
High Pressure ◽  
Raman Spectra ◽  
Vibrational Spectra ◽  
Unit Cell ◽  
High Density ◽  
Monoclinic Unit Cell ◽  
Vibrational Study

Raman and IR vibrational spectra confirm two molecular units associated with the monoclinic unit cell of nitroethane under high pressure. Raman spectra are extremely sensitive to predicted effects of unit cell distortion due to changes in H-bonding.

scholarly journals High density of shear bands in the Vitreloy bulk metallic glass subjected to high-pressure torsion

2021 ◽  
Vol 1008 ◽  
pp. 012031
Author(s):  
Vasily Astanin ◽  
Dmitry Gunderov ◽  
Zhi Qiang Ren ◽  
Ruslan Valiev ◽  
Jing Tao Wang
Keyword(s):  
High Pressure ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
High Pressure Torsion ◽  
Shear Bands ◽  
High Density

Anion packing density: a universal quantity for both dense and porous crystalline inorganic phases

2002 ◽  
Vol 58 (3) ◽  
pp. 457-462 ◽  
Author(s):  
F. Liebau ◽  
H. Küppers
Keyword(s):  
High Pressure ◽  
Packing Density ◽  
Three Dimensional ◽  
Ionic Radii ◽  
Generalized Framework ◽  
Molal Volumes ◽  
Definition Of ◽  
Anion Packing ◽  
Very High ◽  
Framework Density

To compare densities of inorganic high-pressure phases their molal volumes or specific gravities are usually employed, whereas for zeolites and other microporous materials the so-called framework density, FD, is applied. The definition of FD, which refers only to phases with three-dimensional tetrahedron frameworks, is extended to a `generalized framework density' d f, which is independent of the dimensionality of the framework and the coordination number(s) of the framework cations. In this paper the anion packing density, d ap, is introduced as a new quantity which is not only applicable to any inorganic phase but, in contrast to FD and d f, also allows quantitative comparisons to be made for crystalline inorganic phases of any kind. The anion packing density can readily be calculated if the volume and content of the unit cell and the radii of the anions of a phase are known. From d ap values calculated for high-pressure silica polymorphs studied under very high pressure, it is concluded that Shannon–Prewitt effective ionic radii do not sufficiently take into account the compressibility of the anions.

scholarly journals Gaseous combustion at high pressures. —Part X. The co-volume corrections, maximum temperatures and dissociation of steam and carbon dioxide in explosions

1928 ◽  
Vol 119 (782) ◽  
pp. 464-480
Keyword(s):  
Carbon Dioxide ◽  
High Pressure ◽  
Internal Energy ◽  
High Temperatures ◽  
High Pressures ◽  
Internal Combustion ◽  
Systematic Survey ◽  
Explosion Method ◽  
Maximum Temperatures ◽  
Very High

During the researches upon high-pressure explosions of carbonic oxide-air, hydrogen-air, etc., mixtures, which have been described in the previous papers of this series, a mass of data has been accumulated relating to the influence of density and temperature upon the internal energy of gases and the dissociation of steam and carbon dioxide. Some time ago, at Prof. Bone’s request, the author undertook a systematic survey of the data in question, and the present paper summarises some of the principal results thereof, which it is hoped will throw light upon problems interesting alike to chemists, physicists and internal-combustion engineers. The explosion method affords the only means known at present of determining the internal energies of gases at very high temperatures, and it has been used for this purpose for upwards of 50 years. Although by no means without difficulties, arising from uncertainties of some of the assumptions upon which it is based, yet, for want of a better, its results have been generally accepted as being at least provisionally valuable. Amongst the more recent investigations which have attracted attention in this connection should be mentioned those of Pier, Bjerrum, Siegel and Fenning, all of whom worked at low or medium pressures.

A Transparent and Tough β-Si3N4 Ceramic with a Whiskery Microstructure

2015 ◽  
Vol 655 ◽  
pp. 1-5
Author(s):  
Peng Xi Li ◽  
Hong Qiang Wang ◽  
Liu Cheng Gui ◽  
Jun Li ◽  
Hai Long Zhang ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Amorphous Phase ◽  
Hot Pressing ◽  
High Density ◽  
Indentation Fracture ◽  
Indentation Fracture Toughness ◽  
Resultant Material

The transparent β-Si3N4ceramic with a whisker-like microstructure was prepared by hot-pressing at 2000 °C for 26 h, with MgSiN2as an additive. The resultant material achieves the maximum transmittance of 70 % at the wavelength of about 2.5 μm and the transmittance value keeps higher than 60 % in the range of 700-4500 nm wavelength, which is attributed to the very small amount of the intergranular amorphous phase along with high density. The present transparent β-Si3N4ceramic exhibits an indentation fracture toughness of 7.2±0.3 MPa m1/2.

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