Using helium as background gas to avoid hydrogen brittleness for MgB2 film fabrication on niobium substrate by HPCVD

2016 ◽  
Vol 524 ◽  
pp. 13-17 ◽  
Author(s):  
Xin Guo ◽  
Zhimao Ni ◽  
Lizhi Chen ◽  
Hui Hu ◽  
Can Yang ◽  
...  
Keyword(s):  
Hydrogen Brittleness ◽  
Mgb2 Film ◽  
Film Fabrication ◽  
Background Gas

Generation and origin of natural gas in Lower Palaeozoic shales from southern Sweden

1969 ◽  
pp. 37-40
Author(s):  
Niels Hemmingsen Schovsbo ◽  
Arne Thorshøj Nielsen
Keyword(s):  
Source Rocks ◽  
Southern Sweden ◽  
Hydrocarbon Gases ◽  
Biogenic Gas ◽  
South Central ◽  
Alum Shale ◽  
Marine Source ◽  
Lower Palaeozoic ◽  
Background Gas ◽  
Origin Of Natural Gas

The Lower Palaeozoic succession in Scandinavia includes several excellent marine source rocks notably the Alum Shale, the Dicellograptus shale and the Rastrites Shale that have been targets for shale gas exploration since 2008. We here report on samples of these source rocks from cored shallow scientific wells in southern Sweden. The samples contain both free and sorbed hydrocarbon gases with concentrations significantly above the background gas level. The gases consist of a mixture of thermogenic and bacterially derived gas. The latter likely derives from both carbonate reduction and methyl fermentation processes. The presence of both thermogenic and biogenic gas in the Lower Palaeozoic shales is in agreement with results from past and present exploration activities; thermogenic gas is a target in deeply buried, gas-mature shales in southernmost Sweden, Denmark and northern Poland, whereas biogenic gas is a target in shallow, immature-marginally mature shales in south central Sweden. We here document that biogenic gas signatures are present also in gas-mature shallow buried shales in Skåne in southernmost Sweden.

High entropy silicides: CALPHAD-guided prediction and thin film fabrication

2021 ◽  
Vol 201 ◽  
pp. 113914
Author(s):  
Alexandra L. Vyatskikh ◽  
Benjamin E. MacDonald ◽  
Alexander D. Dupuy ◽  
Enrique J. Lavernia ◽  
Julie M. Schoenung ◽  
...  
Keyword(s):  
Thin Film ◽  
High Entropy ◽  
Thin Film Fabrication ◽  
Film Fabrication

Magnetic τ-MnAlC thin film fabrication by high-vacuum thermal evaporation

2021 ◽  
pp. 129657
Author(s):  
J.D. Gamez ◽  
H. Martínez-Sánchez ◽  
J.L. Valenzuela ◽  
L. Marín ◽  
L.A. Rodríguez ◽  
...  
Keyword(s):  
Thin Film ◽  
Thermal Evaporation ◽  
High Vacuum ◽  
Thin Film Fabrication ◽  
Vacuum Thermal Evaporation ◽  
Film Fabrication

scholarly journals Growth and structure of multiphase gas in the cloud-crushing problem with cooling

2020 ◽  
Vol 501 (1) ◽  
pp. 1143-1159
Author(s):  
Vijit Kanjilal ◽  
Alankar Dutta ◽  
Prateek Sharma
Keyword(s):  
Mixing Layer ◽  
Cooling Time ◽  
Radiative Cooling ◽  
Late Time ◽  
Dense Gas ◽  
Mixed Gas ◽  
Continuous Growth ◽  
Dense Cloud ◽  
Set Up ◽  
Background Gas

ABSTRACT We revisit the problem of the growth of dense/cold gas in the cloud-crushing set-up with radiative cooling. The relative motion between the dense cloud and the diffuse medium produces a turbulent boundary layer of mixed gas with a short cooling time. This mixed gas may explain the ubiquity of the range of absorption/emission lines observed in various sources such as the circumgalactic medium and galactic/stellar/active galactic nucleus outflows. Recently, Gronke & Oh showed that the efficient radiative cooling of the mixed gas can lead to continuous growth of the dense cloud. They presented a threshold cloud size for the growth of dense gas that was contradicted by the more recent works of Li et al. & Sparre et al. These thresholds are qualitatively different as the former is based on the cooling time of the mixed gas whereas the latter is based on the cooling time of the hot gas. Our simulations agree with the threshold based on the cooling time of the mixed gas. We argue that the radiative cloud-crushing simulations should be run long enough to allow for the late-time growth of the dense gas due to cooling of the mixed gas but not so long that the background gas cools catastrophically. Moreover, the simulation domain should be large enough that the mixed gas is not lost through the boundaries. While the mixing layer is roughly isobaric, the emissivity of the gas at different temperatures is fundamentally different from an isobaric single-phase steady cooling flow.

A low background gas scintillation proportional counter

1988 ◽  
Vol 264 (2-3) ◽  
pp. 528-530 ◽  
Author(s):  
Sigenori Miyamoto ◽  
Makoto Saito ◽  
Kazuhiro Kimura ◽  
Hiroshi Tsunemi ◽  
Shunjii Kitamoto
Keyword(s):  
Proportional Counter ◽  
Low Background ◽  
Background Gas

Measurement of the hydrogen brittleness of structural materials

1979 ◽  
Vol 15 (3) ◽  
pp. 193-202
Author(s):  
V. V. Panasyuk ◽  
S. E. Kovchik ◽  
G. I. Smoroda
Keyword(s):  
Structural Materials ◽  
Hydrogen Brittleness

Effect of Non-equilibrium Pulsed Ejection of Si Species into Background Gas on the Formation of Si Nanocrystallite and Nanocrystal-film

2011 ◽  
Vol 1305 ◽  
Author(s):  
Ikurou Umezu ◽  
Shunto Okubo ◽  
Akira Sugimura
Keyword(s):  
Laser Ablation ◽  
Film Growth ◽  
Pulsed Laser ◽  
Pulsed Laser Ablation ◽  
Hydrogen Gas ◽  
Gas Pressure ◽  
Spatial Confinement ◽  
The Individual ◽  
Background Gas ◽  
Non Equilibrium

ABSTRACTThe Si nanocrystal-films are prepared by pulsed laser ablation of Si target in a mixture of helium and hydrogen gas. The total gas pressure and hydrogen partial gas pressure were varied to control structure of nanocrystal-film. The surface of Si nanocrystallite was hydrogenated and degree of hydrogenation increased with increasing hydrogen partial gas pressure. The aggregate structure of nanocrystal-film depended on both the total gas pressure and the hydrogen partial gas pressure. The former and the latter alter spatial confinement of Si species during deposition and the surface hydrogenation of individual nanocrystal, respectively. Spatial confinement increases probability of collision between nanocrystals in the plume. While, surface hydrogenation prevents coalescence of nanocrystals. The individual or aggregated nanocrystals formed in the plume reach the substrate and the nanocrystal-film is deposited on the substrate. The non-equilibrium growth processes during pulsed laser ablation are essential for the formation of the surface structure and the subsequent nanocrystal-film growth. Our results indicate that the structure of nanocrystal-film depends on the probabilities of collision and coalescence between nanocrystals in the plume. These probabilities can be varied by controlling the total gas pressure and the hydrogen partial gas pressure.

scholarly journals High temperature ultrasonic sensor for fission gas characterization in MTR harsh environment

2018 ◽  
Vol 170 ◽  
pp. 04008
Author(s):  
O. Gatsa ◽  
P. Combette ◽  
E. Rozenkrantz ◽  
D. Fourmentel ◽  
C. Destouches ◽  
...  
Keyword(s):  
High Temperature ◽  
Thick Film ◽  
Screen Printing ◽  
Bismuth Titanate ◽  
Elevated Temperatures ◽  
Ultrasonic Sensor ◽  
High Resistivity ◽  
Materials Testing ◽  
Coupling Coefficients ◽  
Film Fabrication

In the contemporary world, the measurements in hostile environment is one of the predominant necessity for automotive, aerospace, metallurgy and nuclear plant. The measurement of different parameters in experimental reactors is an important point in nuclear power strategy. In the near past, IES (Institut d’Électronique et des Systèmes) on collaboration with CEA (Commissariat à l’Energie Atomique et aux Energies Alternatives) have developed the first ultrasonic sensor for the application of gas quantity determination that has been tested in a Materials Testing Reactor (MTR). Modern requirements state to labor with the materials that possess stability on its parameters around 350°C in operation temperature. Previous work on PZT components elaboration by screen printing method established the new basis in thick film fabrication and characterization in our laboratory. Our trials on Bismuth Titanate ceramics showed the difficulties related to high electrical conductivity of fabricated samples that postponed further research on this material. Among piezoceramics, the requirements on finding an alternative solution on ceramics that might be easily polarized and fabricated by screen printing approach were resolved by the fabrication of thick film from Sodium Bismuth Titanate (NBT) piezoelectric powder. This material exhibits high Curie temperature, relatively good piezoelectric and coupling coefficients, and it stands to be a good solution for the anticipated application. In this paper, we present NBT thick film fabrication by screen printing, characterization of piezoelectric, dielectric properties and material parameters studies in dependence of temperature. Relatively high resistivity in the range of 1.1013 Ohm.cm for fabricated thick film is explained by Aurivillius structure in which a-and b-layers form perovskite structure between oxides of c-layer. Main results of this study are presented and discussed in terms of feasibility for an application to a new sensor device operating at high temperature level (400°). Piezoelectric parameters enhancement and loss reduction at elevated temperatures are envisaged to be optimized. Further sensor development and test in MTR are expected to be realized in the near future.

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