Detecting Weak Quantum Magnetism at High Pressures

2021 ◽  
Vol 1 ◽  
Keyword(s):  
High Pressure ◽  
Magnetic Materials ◽  
High Pressures ◽  
Quantum Magnetism ◽  
Quantum Magnets ◽  
Weakly Magnetic

Improved device and method to measure magnetization under high pressure was developed, which brings a quick tool to screen phases of interest in weakly magnetic materials including quantum magnets.

Peculiarities of high-pressure hydrogen adsorption on Pt catalyzed Cu-BTC metal–organic framework

2021 ◽  
Vol 23 (7) ◽  
pp. 4277-4286
Author(s):  
S. V. Chuvikov ◽  
E. A. Berdonosova ◽  
A. Krautsou ◽  
J. V. Kostina ◽  
V. V. Minin ◽  
...  
Keyword(s):  
High Pressure ◽  
High Pressures ◽  
Hydrogen Adsorption ◽  
Metal Organic Framework ◽  
Pt Catalyst ◽  
Metal Organic ◽  
Pt Catalyzed ◽  
Pressure Hydrogen ◽  
Organic Framework

Pt-Catalyst plays a key role in hydrogen adsorption by Cu-BTC at high pressures.

scholarly journals Crystal and electronic structure engineering of tin monoxide by external pressure

2021 ◽  
Author(s):  
Kun Li ◽  
Junjie Wang ◽  
Vladislav A. Blatov ◽  
Yutong Gong ◽  
Naoto Umezawa ◽  
...  
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Band Gap ◽  
High Pressures ◽  
Low Pressure ◽  
Widespread Application ◽  
Space Group ◽  
Tin Monoxide ◽  
High Possibility ◽  
Pressure Phase

AbstractAlthough tin monoxide (SnO) is an interesting compound due to its p-type conductivity, a widespread application of SnO has been limited by its narrow band gap of 0.7 eV. In this work, we theoretically investigate the structural and electronic properties of several SnO phases under high pressures through employing van der Waals (vdW) functionals. Our calculations reveal that a metastable SnO (β-SnO), which possesses space group P21/c and a wide band gap of 1.9 eV, is more stable than α-SnO at pressures higher than 80 GPa. Moreover, a stable (space group P2/c) and a metastable (space group Pnma) phases of SnO appear at pressures higher than 120 GPa. Energy and topological analyses show that P2/c-SnO has a high possibility to directly transform to β-SnO at around 120 GPa. Our work also reveals that β-SnO is a necessary intermediate state between high-pressure phase Pnma-SnO and low-pressure phase α-SnO for the phase transition path Pnma-SnO →β-SnO → α-SnO. Two phase transition analyses indicate that there is a high possibility to synthesize β-SnO under high-pressure conditions and have it remain stable under normal pressure. Finally, our study reveals that the conductive property of β-SnO can be engineered in a low-pressure range (0–9 GPa) through a semiconductor-to-metal transition, while maintaining transparency in the visible light range.

scholarly journals The thermal conductivity of the Earth's core and implications for its thermal and compositional evolution

2020 ◽  
Author(s):  
Kenji Ohta ◽  
Kei Hirose
Keyword(s):  
Thermal Conductivity ◽  
High Pressure ◽  
Thermal History ◽  
Diamond Anvil Cell ◽  
High Pressures ◽  
Iron Alloys ◽  
Compositional Evolution ◽  
The Earth ◽  
Diamond Anvil ◽  
High Pressures And Temperatures

Abstract Precise determinations of the thermal conductivity of iron alloys at high pressures and temperatures are essential for understanding the thermal history and dynamics of the metallic cores of the Earth. We review relevant high-pressure experiments using a diamond-anvil cell and discuss implications of high core conductivity for its thermal and compositional evolution.

On the Negative Excess Isotherms for Methane Adsorption at High Pressure: Modeling and Experiment

SPE Journal ◽  
2019 ◽  
Vol 24 (06) ◽  
pp. 2504-2525 ◽  
Author(s):  
Jing Li ◽  
Keliu Wu ◽  
Zhangxin Chen ◽  
Kun Wang ◽  
Jia Luo ◽  
...  
Keyword(s):  
High Pressure ◽  
Mass Balance ◽  
High Pressures ◽  
Pore Wall ◽  
Void Volume ◽  
Excess Adsorption ◽  
Experimental Conditions ◽  
Accessible Volume ◽  
Adsorbed Phase

Summary An excess adsorption amount obtained in experiments is always determined by mass balance with a void volume measured by helium (He) –expansion tests. However, He, with a small kinetic diameter, can penetrate into narrow pores in porous media that are inaccessible to adsorbate gases [e.g., methane (CH4)]. Thus, the actual accessible volume for a specific adsorbate is always overestimated by an He–based void volume; such overestimation directly leads to errors in the determination of excess isotherms in the laboratory, such as “negative isotherms” for gas adsorption at high pressures, which further affects an accurate description of total gas in place (GIP) for shale–gas reservoirs. In this work, the mass balance for determining the adsorbed amount is rewritten, and two particular concepts, an “apparent excess adsorption” and an “actual excess adsorption,” are considered. Apparent adsorption is directly determined by an He–based volume, corresponding to the traditional treatment in experimental conditions, whereas actual adsorption is determined by an adsorbate–accessible volume, where pore–wall potential is always nonpositive (i.e., an attractive molecule/pore–wall interaction). Results show the following: The apparent excess isotherm determined by the He–based volume gradually becomes negative at high pressures, but the actual one determined by the adsorbate–accessible volume always remains positive.The negative adsorption phenomenon in the apparent excess isotherm is a result of the overestimation in the adsorbate–accessible volume, and a larger overestimation leads to an earlier appearance of this negative adsorption.The positive amount in the actual excess isotherm indicates that the adsorbed phase is always denser than the bulk gas because of the molecule/pore–wall attraction aiding the compression of the adsorbed molecules. Practically, an overestimation in pore volume (PV) is only 3.74% for our studied sample, but it leads to an underestimation reaching up to 22.1% in the actual excess amount at geologic conditions (i.e., approximately 47 MPa and approximately 384 K). Such an overestimation in PV also underestimates the proportions of the adsorbed–gas amount to the free–gas amount and to the total GIP. Therefore, our present work underlines the importance of a void volume in the determination of adsorption isotherms; moreover, we establish a path for a more–accurate evaluation of gas storage in geologic shale reservoirs with high pressure.

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.

scholarly journals Annealing of Al-Zn-Mg-Cu Alloy at High Pressures: Evolution of Microstructure and the Corrosion Behavior

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2076
Author(s):  
Chuanjun Suo ◽  
Pan Ma ◽  
Yandong Jia ◽  
Xiao Liu ◽  
Xuerong Shi ◽  
...  
Keyword(s):  
High Pressure ◽  
High Pressures ◽  
Electrochemical Impedance ◽  
Extrusion Direction ◽  
Corrosion Properties ◽  
Cu Alloy ◽  
The Matrix ◽  
Annealing Pressure ◽  
Corrosion Pits ◽  
Evolution Of Microstructure

Extruded Al-Zn-Mg-Cu alloy samples with grains aligned parallel to the extrusion direction were subjected to high-pressure annealing. The effects of annealing pressure on the microstructure, hardness, and corrosion properties (evaluated using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS)) were investigated. Phase analysis showed the presence of MgZn2 and α-Al phases, the MgZn2 phase dissolved into the matrix, and its amount decreased with the increasing annealing pressure. The recrystallization was inhibited, and the grains were refined, leading to an increase in the Vickers hardness with increasing the annealing pressure. The corrosion resistance was improved after high-pressure treatment, and a stable passivation layer was observed. Meanwhile, the number of corrosion pits and the width of corrosion cracks decreased in the high-pressure annealed samples.

Chemistry, Physical Nature, and Rheology of Aqueous Stimulation Foams

1981 ◽  
Vol 21 (04) ◽  
pp. 410-414 ◽  
Author(s):  
David L. Holcomb ◽  
Ed Callaway ◽  
Lynn L. Curry
Keyword(s):  
High Pressure ◽  
Surfactant Concentration ◽  
High Pressures ◽  
Foam Stability ◽  
Streaming Potential ◽  
Physical Nature ◽  
Chemical Additives ◽  
Laboratory Equipment ◽  
Foaming Agent ◽  
Fracturing Fluids

Abstract Laboratory equipment has been designed specificallyto study effectively the microscopic structure offlowing foams at high pressures. In addition, application of foaming-agent optimization techniquesto design stable foams at varying foam qualities isdemonstrated at high pressures - i.e., 500 to 2,000psig (3448 to 13 792 kPa). Capillary viscosity datafor these foams is established and correlated with avideo-photomicroscopic study of the flowing foamand their designated bubble qualities. Foaming-agent screening information from the tests is providedindicating the foaming-agent generic chemistry thatallows optimal foam stability under high-pressure conditions. Introduction The study of contemporary foam rheology has arather interrupted history beginning with Fried'swork in 1961 on a foam drive process, which was followed by Raza and Marsden's 1965 paper onrheology and streaming potential. During 1969Blauer et al. studied foam flow properties andmade successful comparisons of data obtained incapillary viscometer tests and actual oilfield tubulardata. These investigations lead to the development ofdata and calculated procedures for using high-qualityfoams as fracturing fluids to transport proppanteffectively with extremely low formation damage as aresult of smaller amounts of water or liquid incontact with the formation. With all the theoretical depiction of flowing foamstructure, it was felt that a study was needed to showvisually the actual flowing foam under pressure. Thiswas undertaken in a study' where oil-foamingsurfactant concentrations were optimized using anapparatus similar to ours. (The majority of foamstimulation treatments use aqueous bases, and thisstudy was conducted exclusively with them.) The goal of this project was to design equipmentthat could be adapted to a TV camera/microscopesystem to allow videotaping of flowing foam in aview cell under pressure. To study effectively thechemical nature of four different surfactant foams, the temperature was kept at 80 deg. F (26.7 deg. C)throughout the study. Also, one foam quality of88%, or 88% nitrogen and 12% water was chosenusing 2% KCl water as the liquid phase. Selected pictures from the videotape are presented to show thesuccession of bubble-structure change with pressure.In addition, the effect of surfactant concentration (which had been thought to play a small role, if any, in the rheology of foams) is shown. This allows aneven greater ability to optimize surfactant concentration in the production of stable foams forstimulation. The subjective bubble-quality scale of Holcomb etal. is refined by showing the average bubblediameters at various study pressures and is demonstrated photographically in Figs. 1 through 3.For the viscosity tests through the capillaryviscometer system, a constant 1,000-psi input pressure was maintained for the generation of foam. Testing Apparatus, Procedure, and Chemical Additives The high-pressure test apparatus was designed tomeet the rate requirements for a laboratory testsample of 700 cm (liquid) or more. The system iscapable of pressures to 3,000 psi (20 683 kPa). The pump is a Williams Oscillamatic TM single-strokemodel with a pressure rating to 10,000 psi (68 946kPa). All main lines are 6.35 mm in diameter. Trunklines to the gauges are 3.175-mm-diameter tubing.All tubing in the apparatus is 316 stainless steel. (SeeFig. 4.) SPEJ P. 410^

Crystal Field Analysis of the Magnetization Curves of HoFe11Ti under High Pressure

2013 ◽  
Vol 818 ◽  
pp. 72-76 ◽  
Author(s):  
Gang Su
Keyword(s):  
High Pressure ◽  
Hydrogen Atom ◽  
Electric Field ◽  
Single Crystals ◽  
High Pressures ◽  
Field Analysis ◽  
Magnetization Curves ◽  
Crystalline Electric Field ◽  
Crystalline Anisotropy ◽  
Magneto Crystalline Anisotropy

The crystalline electric field parameters Anmfor HoFe11Ti under different pressures were evaluated by fitting calculations to the magnetization curves measured on the single crystals at several temperatures. It was found that magneto-crystalline anisotropy has been changed by high pressure and the Anmfor HoFe11Ti under high pressures are strikingly different from Anmfor the corresponding HoFe11Ti H with interstitial hydrogen atom.

Monoclinic FeO at high pressures

2008 ◽  
Vol 223 (7/2008) ◽  
Author(s):  
Innokenty Kantor ◽  
Alexander Kurnosov ◽  
Catherine McCammon ◽  
Leonid Dubrovinsky
Keyword(s):  
High Pressure ◽  
Iron Oxide ◽  
Single Crystal ◽  
Diffraction Study ◽  
High Pressures ◽  
X Ray Diffraction ◽  
X Ray

AbstractA high-pressure quasi-single crystal X-ray diffraction study of a synthetic iron oxide Fe

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