scholarly journals Laboratory Simulation of Low Earth Orbit (LEO) Atomic Oxygen Effects

1996 ◽  
Vol 39 (2) ◽  
pp. 23-28
Author(s):  
George Caledonia ◽  
Robert Krech ◽  
David Oakes
Keyword(s):  
Oxygen Atom ◽  
Low Earth Orbit ◽  
Laboratory Simulation ◽  
Test Duration ◽  
Erosion Rates ◽  
Oxygen Effects ◽  
Ambient Oxygen ◽  
Atom Source ◽  
Oxidative Effects ◽  
Oxygen Atoms

Our pulsed fast oxygen atom source has been used extensively over the last 9 yr to investigate the effects of ambient oxygen atoms that impact materials placed in LEO. During this period, we have irradiated over 2000 material samples with 8 km/s oxygen atoms generated in our source. Typical irradiance level is 3 × 1020 O atoms/cm2 although some materials have been irradiated to fluence levels as high as 6 × 1021 O atoms/cm2. In this paper, we review the operating principles and characteristics of our source along with the diagnostic and handling procedures appropriate to material testing. We then present representative data on the velocity dependence of oxygen atom erosion rates (the PSI source provides oxygen atoms tunable over the velocity range of 5 to 12 km/s) as well as the dependence on material temperature. Specific examples of nonlinear oxidative effects related to surface contamination and test duration will also be provided.

Fast oxygen atom facility for studies related to low earth orbit activities

1992 ◽  
Author(s):  
G. CALEDONIA ◽  
R. KRECH ◽  
B. UPSCHULTE ◽  
D. SONNENFROH ◽  
D. OAKES ◽  
...  
Keyword(s):  
Oxygen Atom ◽  
Low Earth Orbit ◽  
Earth Orbit

Nonclassical oxygen atom transfer reactions of an eight-coordinate dioxomolybdenum(vi) complex

2021 ◽  
Author(s):  
Leila G. Ranis ◽  
Jacqueline Gianino ◽  
Justin M. Hoffman ◽  
Seth N. Brown
Keyword(s):  
Oxygen Atom ◽  
Transfer Reaction ◽  
Transfer Reactions ◽  
Atom Transfer ◽  
Oxygen Atom Transfer ◽  
Oxygen Atom Transfer Reactions ◽  
Atom Transfer Reactions ◽  
Oxygen Atoms

Eight-coordinate MoO2(DOPOQ)2 can donate two oxygen atoms to substrates such as phosphines in a four-electron nonclassical oxygen atom transfer reaction.

AIM study on the transferability of the oxygen atom in linear ethers

2000 ◽  
Vol 78 (12) ◽  
pp. 1535-1543 ◽  
Author(s):  
Antonio Vila ◽  
Enrique Carballo ◽  
Ricardo A Mosquera
Keyword(s):  
Dipole Moment ◽  
Oxygen Atom ◽  
Potential Energy ◽  
Critical Points ◽  
Wave Functions ◽  
Electron Population ◽  
Alkyl Radicals ◽  
Energy Interaction ◽  
Interaction Dipole Moment ◽  
Oxygen Atoms

The integrated values of the electron population, electron energy, nucleus–electron potential energy interaction, dipole moment and volume of the oxygen atoms, and the main properties of the O—C bond critical points, were determined by employing the theory of atoms in molecules and 6-31++G**//6-31G* wave functions for a series of 25 unbranched alkyl monoethers. These results were used to assess the degree of approximate transferability of the oxygen atom along this series in terms of the particular alkyl radicals bonded to it. It has been found that a set of six different oxygen atoms is necessary to classify all the computed values. It can be established that the oxygen atoms bonded to propyl and larger radicals can be treated, in practice, as a transferable fragment, while those bonded to at least one smaller radical are specific. Though the total HF energy and the available experimental heats of formation are well fitted by a traditional additivity scheme that distinguishes only among O, CH2, and CH3 units, it has been found that the energy properties are influenced by the size of the molecule.Key words: transferability, AIM theory, ethers.

Atomic oxygen effects on polymers containing silicon or phosphorus: Mass loss, erosion yield, and surface morphology

2018 ◽  
Vol 31 (8) ◽  
pp. 969-976 ◽  
Author(s):  
Wang Chunbo ◽  
Jiang Haifu ◽  
Tian Dongbo ◽  
Qin Wei ◽  
Chen Chunhai ◽  
...  
Keyword(s):  
Surface Morphology ◽  
Mass Loss ◽  
Atomic Oxygen ◽  
Low Earth Orbit ◽  
Relative Order ◽  
Oxygen Effects ◽  
Arylene Ether ◽  
Inorganic Coatings ◽  
Oligomeric Silsesquioxane ◽  
Surface Morphologies

The differences among polymers containing silicon or phosphorus, 20% polyhedral oligomeric silsesquioxane polyimide (20%-POSS-PI), 30% polysiloxane- block-polyimides (30%-PSX-PI), poly(siloxane imide) homopolymer (PSX-PI), and arylene ether phosphine oxide homopolymer (P-PPO), on mass loss, erosion yield, and surface morphology were elucidated. The tolerance against atomic oxygen (AO) was improved versus Kapton®H after introducing silicon or phosphorus to the polymers. The relative order of the mass loss was PSX-PI < P-PPO < 20%-POSS-PI < 30%-PSX-PI. In contrast, the erosion yields of 30%-PSX-PI, 20%-POSS-PI, and P-PPO decreased by orders of magnitude (PSX-PI declined by about two orders). The surface of Kapton®H was seriously eroded by AO exhibiting a “carpet-like” shape, and the roughness of the surface of Kapton®H became remarkable as the AO fluence increased. PSX-PI, P-PPO, 20%-POSS-PI, and 30%-PSX-PI at an AO fluence of 5.2 × 1020 atoms/cm2 had different surface morphologies, and the relative order of the surface roughness was PSX-PI < 30%-PSX-PI < 20%-POSS-PI < P-PPO. The 30%-PSX-PI and PSX-PI had minor mass losses and a smooth surface. This kind of material might replace inorganic coatings for applications in low earth orbit.

scholarly journals Crystal structure of β-Zn3(PO4)2

1967 ◽  
Vol 45 (20) ◽  
pp. 2303-2316 ◽  
Author(s):  
J. S. Stephens ◽  
C. Calvo
Keyword(s):  
Crystal Structure ◽  
Oxygen Atom ◽  
Lattice Parameters ◽  
Monoclinic Space Group ◽  
Space Group ◽  
Basic Cation ◽  
Cation Coordination ◽  
Oxygen Atoms

β-Zn3(PO4)2 crystallizes in the monoclinic space group P 21/c with lattice parameters, a = 9.393(3) Å, b = 9.170(6) Å, c = 8.686(3) Å, β = 125.73(10)°, and Z = 4. The three independent cations are strongly ligated to 4, 5, and 5 oxygen atoms, with average Zn—O bond distances of 1.98 ± 0.09 Å, 2.10 ± 0.10 Å, and 2.08 ± 0.13 Å respectively. In addition there are two longer Zn—O distances of 2.51 Å and 2.55 Å in this structure. The PO4 groups exist as independent, nearly regular tetrahedra, with each oxygen atom ligated to two cations. Unlike the structures found for the α and γ phases of Zn3(PO4)2, which contain ribbons and sheets respectively as the basic cation coordination motif, the structure of β-Zn3(PO4)2 contains interconnected sheets.

Direct insertion of oxygen atoms into the backbonds of subsurface Si atoms using translational energies of oxygen atom beams

2007 ◽  
Vol 91 (3) ◽  
pp. 033504 ◽  
Author(s):  
Masahito Tagawa ◽  
Kumiko Yokota ◽  
Shinnosuke Tsumamoto ◽  
Chie Sogo ◽  
Akitaka Yoshigoe ◽  
...  
Keyword(s):  
Oxygen Atom ◽  
Oxygen Atoms

Room-temperature growth of ZrO2 thin films using a novel hyperthermal oxygen-atom source

1999 ◽  
Vol 17 (1) ◽  
pp. 14-18 ◽  
Author(s):  
Elmar Wisotzki ◽  
Adam G. Balogh ◽  
Horst Hahn ◽  
John T. Wolan ◽  
Gar B. Hoflund
Keyword(s):  
Thin Films ◽  
Oxygen Atom ◽  
Room Temperature ◽  
Temperature Growth ◽  
Atom Source

Oxidation catalysis via visible-light water activation of a [Ru(bpy)3]2+ chromophore BSA–metallocorrole couple

2016 ◽  
Vol 45 (2) ◽  
pp. 706-710 ◽  
Author(s):  
Christian Herrero ◽  
Annamaria Quaranta ◽  
Rémy Ricoux ◽  
Alexandre Trehoux ◽  
Atif Mahammed ◽  
...  
Keyword(s):  
Oxygen Atom ◽  
Visible Light ◽  
Ruthenium Complex ◽  
Oxidation Catalysis ◽  
Light Water ◽  
Enantioselective Oxidation ◽  
Water Activation ◽  
Atom Source ◽  
Artificial Metalloenzyme

Light induced enantioselective oxidation of thioanisole with water as the oxygen atom source is catalyzed by a Mn-corrole–BSA artificial metalloenzyme in the presence of a photoactivable ruthenium complex.

ChemInform Abstract: Enantioselective Epoxidation of Isoflavones by Jacobsen′s Mn(III)Salen Catalysts and Dimethyldioxirane Oxygen-Atom Source.

ChemInform ◽  
2010 ◽  
Vol 29 (33) ◽  
pp. no-no
Author(s):  
W. ADAM ◽  
R. T. FELL ◽  
A. LEVAI ◽  
T. PATONAY ◽  
K. PETERS ◽  
...  
Keyword(s):  
Oxygen Atom ◽  
Enantioselective Epoxidation ◽  
Atom Source

Crystal Structure of α-Zn2V2O7

1973 ◽  
Vol 51 (7) ◽  
pp. 1004-1009 ◽  
Author(s):  
Ramanathan Gopal ◽  
Crispin Calvo
Keyword(s):  
Crystal Structure ◽  
Oxygen Atom ◽  
Bond Length ◽  
Fold Axis ◽  
Full Matrix ◽  
X Ray ◽  
R Value ◽  
The Individual ◽  
Zn Ions ◽  
Oxygen Atoms

α-Zn2V2O7 is monoclinic with lattice parameters a = 7.429(5), b = 8.340(3), c = 10.098(3) Å, β = 111.37(5)°, Z = 4 and space group C2/c. The structure was refined using a full matrix least-squares with 1034 reflections measured with a quarter-circle General Electric automatic X-ray diffractometer to a final R value of 0.066. The anion consists of a pair of VO4 tetrahedra sharing an oxygen atom which lies on a two-fold axis. The bridging V—O bond length is 1.775(4) Å while the three independent terminal ones are 1.728(4), 1.704(7), and 1.658(8) Å long. These bond lengths are consistent with the charge character around the individual oxygen atoms. The Zn ions are coordinated to five oxygen atoms with Zn—O bonds ranging from 1.973 to 2.088°Å. The structure is similar to that of α-CU2P2O7 and transforms to the thortvietite structure at about 615 °C.

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