The relationship between the pyrolysis of trimethylgallium in the gas phase and that on the surface

1990 ◽  
Vol 68 (5) ◽  
pp. 2538-2540 ◽  
Author(s):  
Masataka Hoshino
Keyword(s):  
Gas Phase ◽  
The Relationship

scholarly journals On the relationship between the basicity of a surface and its ability to catalyze transesterification in liquid and gas phases: the case of MgO

2015 ◽  
Vol 17 (21) ◽  
pp. 14168-14176 ◽  
Author(s):  
Damien Cornu ◽  
Hazar Guesmi ◽  
Guillaume Laugel ◽  
Jean-Marc Krafft ◽  
Hélène Lauron-Pernot
Keyword(s):  
Gas Phase ◽  
Basic Properties ◽  
Gas Phases ◽  
The Relationship

The influence of the basic properties of MgO is not the same for liquid and for gas phase transesterification.

The relationship between the MOCVD parameters and the crystallinity, epitaxy, and domain structure of PbTiO3 films

1994 ◽  
Vol 9 (1) ◽  
pp. 156-163 ◽  
Author(s):  
G.R. Bai ◽  
H.L.M. Chang ◽  
C.M. Foster ◽  
Z. Shen ◽  
D.J. Lam
Keyword(s):  
Gas Phase ◽  
Deposition Temperature ◽  
Substrate Surface ◽  
Chemical Vapor ◽  
Surface Orientation ◽  
Organic Chemical ◽  
Epitaxial Relationship ◽  
Domain Structures ◽  
Vapor Deposition Technique ◽  
The Relationship

Lead- and titanium-based oxide thin films were prepared by the metal-organic chemical vapor deposition technique (MOCVD) and the relationship between the film structures and the processing parameters, such as the ratio of Pb/Ti precursors in the gas phase, substrate materials, substrate surface orientation, and growth temperature, was systematically studied. It was found that whether a single-phase stoichiometric PbTiO3 film could be obtained depended on both the Pb/Ti precursor ratio in the gas phase and the deposition temperature. Under appropriate conditions, stoichiometric PbTiO3, films could be obtained on all the substrates including silicon, MgO, α-Al2O3, SrTiO3, and LaAlO3. The PbTiO3 films grown on silicon substrates were always polycrystalline, whereas epitaxial PbTiO3 films were obtainable on all the other substrates. For epitaxial PbTiO3 films, the epitaxial relationship, crystallinity, and domain structures were found to be a function of both the substrate materials and surface orientation as well as the deposition temperature. X-ray rocking curves (ω scan) of the (100) and (001) planes of PbTiO3 epitaxial film and PbTiO3 single crystal revealed the inherent nature of the domain structures in PbTiO3.

scholarly journals Interstellar Extinction and Elemental Abundances: Individual Sight Lines

2021 ◽  
Vol 257 (2) ◽  
pp. 63
Author(s):  
Wenbo Zuo ◽  
Aigen Li ◽  
Gang Zhao
Keyword(s):  
Gas Phase ◽  
Interstellar Extinction ◽  
Elemental Abundance ◽  
Extinction Curve ◽  
Galactic Chemical Evolution ◽  
Space Telescopes ◽  
Dust Extinction ◽  
Elemental Abundances ◽  
Hydrogen Column Density ◽  
The Relationship

Abstract While it is well recognized that both the Galactic interstellar extinction curves and the gas-phase abundances of dust-forming elements exhibit considerable variations from one sight line to another, as yet most of the dust extinction modeling efforts have been directed to the Galactic average extinction curve, which is obtained by averaging over many clouds of different gas and dust properties. Therefore, any details concerning the relationship between the dust properties and the interstellar environments are lost. Here we utilize the wealth of extinction and elemental abundance data obtained by space telescopes and explore the dust properties of a large number of individual sight lines. We model the observed extinction curve of each sight line and derive the abundances of the major dust-forming elements (i.e., C, O, Si, Mg, and Fe) required to be tied up in dust (i.e., dust depletion). We then confront the derived dust depletions with the observed gas-phase abundances of these elements and investigate the environmental effects on the dust properties and elemental depletions. It is found that for the majority of the sight lines the interstellar oxygen atoms are fully accommodated by gas and dust and therefore there does not appear to be a “missing oxygen” problem. For those sight lines with an extinction-to-hydrogen column density A V /N H ≳ 4.8 × 10−22 mag cm2 H−1 there are shortages of C, Si, Mg, and Fe elements for making dust to account for the observed extinction, even if the interstellar C/H, Si/H, Mg/H, and Fe/H abundances are assumed to be protosolar abundances augmented by Galactic chemical evolution.

scholarly journals Improved High-Pressure, High-Temperature (HPHT) Materials Qualification using Dissolved H<sub>2</sub>S Concentration as the Sour Service Scalable Metric

CORROSION ◽  
10.5006/3867 ◽  
2021 ◽  
Author(s):  
BRENT SHERAR ◽  
Peter Ellis II ◽  
Jing Ning
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Gas Phase ◽  
Stress Cracking ◽  
High Pressure High Temperature ◽  
Sulfide Stress ◽  
Sulfide Stress Cracking ◽  
Sour Service ◽  
The Relationship ◽  
Severity Parameter

Gas phase H&lt;sub&gt;2&lt;/sub&gt;S partial pressure (P&lt;sub&gt;H2S&lt;/sub&gt;) is associated with sulfide stress cracking (SSC) and is routinely used as the ‘scalable’ parameter to qualify materials for high-pressure, high-temperature (HPHT) wells. Candidate materials for HPHT wells routinely require ANSI/NACE MR0175/ISO 15156 compliance because a few mole ppm of H&lt;sub&gt;2&lt;/sub&gt;S at high pressure may place the well beyond the 0.05 psia (0.3 kPa) sour service threshold. P&lt;sub&gt;H2S&lt;/sub&gt; has been accepted historically as the scalable sour severity parameter. However, as the total pressure increases, the relationship between P&lt;sub&gt;H2S&lt;/sub&gt; and the dissolved H&lt;sub&gt;2&lt;/sub&gt;S concentration becomes non-linear. This limits the robustness of P&lt;sub&gt;H2S&lt;/sub&gt; as the sour severity metric. Thus, ISO 15156-1:2020 now permits the use of H2S fugacity (f&lt;sub&gt;H2S&lt;/sub&gt;), H&lt;sub&gt;2&lt;/sub&gt;S activity (a&lt;sub&gt;H2S&lt;/sub&gt;), and H&lt;sub&gt;2&lt;/sub&gt;S aqueous concentration (C&lt;sub&gt;H2S&lt;/sub&gt;) as alternatives for sour testing. This recent revision is based on evidence that f&lt;sub&gt;H2S&lt;/sub&gt; and C&lt;sub&gt;H2S&lt;/sub&gt; each provide better correlations to SSC at elevated total pressures than P&lt;sub&gt;H2S&lt;/sub&gt;. This paper will address the merits and challenges of using f&lt;sub&gt;H2S&lt;/sub&gt; or C&lt;sub&gt;H2S&lt;/sub&gt; to define sour severity: We argue that C&lt;sub&gt;H2S&lt;/sub&gt; is a practical, experimentally verifiable approach, which can be used to validate ionic-equation of state (EOS) frameworks used to characterize mildly sour HPHT environments.

scholarly journals The Formation of a Dispersed Gas System in the Flotation Cells

2019 ◽  
Vol 126 ◽  
pp. 00069
Author(s):  
E.V. Alekseev
Keyword(s):  
Gas Phase ◽  
High Speed ◽  
Separation Process ◽  
Separation Processes ◽  
Environmental Friendliness ◽  
Bubble Separation ◽  
Flotation Cells ◽  
Flotation Cell ◽  
Gas System ◽  
The Relationship

The use of flotation methods for wastewater treatment is due to their advantages in comparison with other methods of gravity separation, for example, sedimentation. The advantages of flotation water treatment methods include the high speed of the separation process, the ability to extract impurities that are close in density to water, environmental friendliness. Flotation methods are based on adsorptive bubble separation processes. Accordingly, the performance of a particular flotator directly depends on the conditions for the implementation of these processes in a particular flotation cell. The aim of the research was to study the relationship between the dispersed gas phase (DGP) and the ratio of the geometric dimensions of the flotation cells based on the proposed shape indicator of the flotation cell. Studies performed on the experimental model of the flotator have established a significant influence of theshape indicator of the flotation cell on such important indicators of the adsorptive bubble separation processes as gas-filling and the DGP floating speed. The evaluation of different forms of flotation cells, in relation to the properties of extracted bubble-particle complexes is given.

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