How to Optimize Critical Current Performance of RE123 Materials by Controlling Oxygen Content

2001 ◽  
Vol 689 ◽  
Author(s):  
Jun-ichi Shimoyama ◽  
Shigeru Horii ◽  
Kenji Otzschi ◽  
Kohji Kishio
Keyword(s):  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Critical Current ◽  
Oxygen Content ◽  
Oxygen Nonstoichiometry ◽  
Thermodynamic Quantities ◽  
Precise Control ◽  
Oxygen Defects ◽  
Re Elements ◽  
Selection Of

ABSTRACTOxygen nonstoichiometry behaviors of REBa2Cu3Oy (RE123: RE= Nd, Sm, Eu, Gd, Dy. Ho and Y) compounds have been precisely determined by the thermogravimetric measurements. Dependence of oxygen content on temperature and oxygen partial pressure were found to slightly depend on the RE element. Thermodynamic quantities of oxygen, such as hO2 and sO2, also varied with RE element. Relationship between Tc and oxygen content is strongly dependent on the RE species. This suggests that pinnig effect due to the oxygen defects is different in each RE123 compound and, therefore, critical current properties of RE123 must be optimized by precise control of oxygen content as well as selection of suitable RE elements.

scholarly journals Oxygen separation from air by the combined temperature swing and pressure swing processes using oxygen storage materials Y1−x(Tb/Ce)xMnO3+δ

2020 ◽  
Vol 55 (33) ◽  
pp. 15653-15666
Author(s):  
Alicja Klimkowicz ◽  
Takao Hashizume ◽  
Kacper Cichy ◽  
Sayaka Tamura ◽  
Konrad Świerczek ◽  
...  
Keyword(s):  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Oxygen Content ◽  
Storage Capacity ◽  
Oxygen Storage Capacity ◽  
Oxygen Storage ◽  
Oxygen Separation ◽  
Storage Materials ◽  
Temperature Swing ◽  
Pressure Swing

Abstract Hexagonal Y1−xRxMnO3+δ (R: other than Y rare earth elements) oxides have been recently introduced as promising oxygen storage materials that can be utilized in the temperature swing processes for the oxygen separation and air enrichment. In the present work, the average and local structures of Tb- and Ce-substituted Y0.7Tb0.15Ce0.15MnO3+δ and Y0.6Tb0.2Ce0.2MnO3+δ materials were studied, and their oxygen storage-related properties have been evaluated. The fully oxidized samples show the presence of a significant amount of the highly oxygen-loaded the so-called Hex3 phase, attaining an average oxygen content of δ ≈ 0.41 for both compositions. Extensive studies of the temperature swing process conducted in air and N2 over the temperature range of 180–360 °C revealed large and reversible oxygen content changes taking place with only a small temperature differences and the high dependence on the oxygen partial pressure. Significant for practical performance, the highest reported for this class of compounds, oxygen storage capacity of 1900 μmol O g−1 in air was obtained for the optimized materials and swing process. In the combined temperature–oxygen partial pressure swing process, the oxygen storage capacity of 1200 μmol O g−1 was achieved.

ChemInform Abstract: Influence of Oxygen Partial Pressure and Oxygen Content on the Wettability in the Copper-Oxygen-Alumina System.

ChemInform ◽  
2010 ◽  
Vol 31 (4) ◽  
pp. no-no
Author(s):  
Matthias Diemer ◽  
Achim Neubrand ◽  
Kevin P. Trumble ◽  
Juergen Roedel
Keyword(s):  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Oxygen Content

The Oxygen Defect Chemistry of La2−xSrxCuO4−x/2+δ

1990 ◽  
Vol 209 ◽  
Author(s):  
Elizabeth J. Opila ◽  
Harry L. Tuller
Keyword(s):  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Oxygen Content ◽  
Defect Chemistry ◽  
Oxygen Stoichiometry ◽  
Oxygen Defect ◽  
Defect Model ◽  
Strontium Concentration ◽  
Partial Pressures ◽  
Equilibrium Oxygen

ABSTRACTThe equilibrium oxygen stoichiometry of La2−xSrxCuO4±y (x=O, 0.2, 0.4, and 1.0) has been determined by TGA at temperatures between 800 and 1050°C and oxygen partial pressures between 1 and 10−4 atmospheres. The changes in oxygen content with temperature, oxygen partial pressure, and strontium concentration are evaluated in terms of a defect model.

AgO Doped YBa2Cu4O8 Superconductor Under High Oxygen Partial Pressure

1991 ◽  
Vol 251 ◽  
Author(s):  
Yuichi Sawai ◽  
K. Ishizaki ◽  
M. Takata ◽  
A. Kuzjukevics
Keyword(s):  
Critical Temperature ◽  
Critical Current Density ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Critical Current ◽  
Current Density ◽  
High Oxygen ◽  
Silver Doping ◽  
High Oxygen Partial Pressure ◽  
Pressing Method

ABSTRACTGeneraly silver doping into YBa2Cu3O7 superconductor improves the critical temperature and critical current density. In this work the silver peroxide was doped into YBa2Cu4O8 superconductor and sintered by the Oxygen Hot Isostatically Pressing method. The critical temperature of the 124 phase increased by silver peroxide doping.

Impact of oxygen content on preferred localization of p- and n-type carriers in La0.5Sr0.5Fe1−xMnxO3−δ

2021 ◽  
Author(s):  
Sergey S. Nikitin ◽  
Alexey A. Markov ◽  
Oleg V. Merkulov ◽  
Andrey V Chukin ◽  
Mikhail Patrakeev
Keyword(s):  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Oxygen Content ◽  
Coulometric Titration ◽  
Defect Chemistry ◽  
Wide Range

The oxygen content in La0.5Sr0.5Fe1−xMnxO3−δ, measured by coulometric titration in a wide range of oxygen partial pressure at various temperatures, was used for defect chemistry analysis. The obtained data were...

scholarly journals Dissociating the effects of oxygen pressure and content on the control of breathing and acute hypoxic response

2019 ◽  
Vol 127 (6) ◽  
pp. 1622-1631 ◽  
Author(s):  
Paolo B. Dominelli ◽  
Sarah E. Baker ◽  
Chad C. Wiggins ◽  
Glenn M. Stewart ◽  
Pavol Sajgalik ◽  
...  
Keyword(s):  
Heart Rate ◽  
Oxygen Partial Pressure ◽  
Partial Pressure ◽  
Oxygen Content ◽  
Oxygen Tension ◽  
Ventilatory Response ◽  
Cardiovascular Responses ◽  
Arterial Oxygen ◽  
Hypoxic Ventilatory Response ◽  
High Affinity

Arterial oxygen tension and oxyhemoglobin saturation ([Formula: see text]) decrease in parallel during hypoxia. Distinguishing between changes in oxygen tension and oxygen content as the relevant physiological stimulus for cardiorespiratory alterations remains challenging. To overcome this, we recruited nine individuals with hemoglobinopathy manifesting as high-affinity hemoglobin [HAH; partial pressure at 50% [Formula: see text] (P50) = 16 ± 0.4 mmHg] causing greater [Formula: see text] at a given oxygen partial pressure compared with control subjects ( n = 12, P50 = 26 ± 0.4 mmHg). We assessed ventilatory and cardiovascular responses to acute isocapnic hypoxia, iso-oxic hypercapnia, and 20 min of isocapnic hypoxia (arterial Po2 = 50 mmHg). Blood gas alterations were achieved with dynamic end-tidal forcing. When expressed as a function of the logarithm of oxygen partial pressure, ventilatory sensitivity to hypoxia was not different between groups. However, there was a significant difference when expressed as a function of [Formula: see text]. Conversely, the rise in heart rate was blunted in HAH subjects when expressed as a function of partial pressure but similar when expressed as a function of [Formula: see text]. Ventilatory sensitivity to hypercapnia was not different between groups. During sustained isocapnic hypoxia, the rise in minute ventilation was similar between groups; however, heart rate was significantly greater in the controls during 3 to 9 min of exposure. Our results support the notion that oxygen tension, not content, alters cellular Po2 in the chemosensors and drives the hypoxic ventilatory response. Our study suggests that in addition to oxygen partial pressure, oxygen content may also influence the heart rate response to hypoxia. NEW & NOTEWORTHY We dissociated the effects of oxygen content and pressure of cardiorespiratory regulation studying individuals with high-affinity hemoglobin (HAH). During hypoxia, the ventilatory response, expressed as a function of oxygen tension, was similar between HAH variants and controls; however, the rise in heart rate was blunted in the variants. Our work supports the notion that the hypoxic ventilatory response is regulated by oxygen tension, whereas cardiovascular regulation may be influenced by arterial oxygen content and tension.

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