The interaction of oxygen with clean metal surfaces

Isobars for the adsorption of O 2 , H 2 and CO on evaporated films of Rh, Mo, W and Fe, of Ch and CO on Ta, Pt and Pd, and of O 2 on Cu, Al and Zn have been obtained. On Rh, Mo and W the rapid adsorption of O 2 and H 2 at -183° C results in formation of monolayers with one atom per surface atom. On Ta, Pt, Pd, Cu, Al and Zn oxygen, and on Fe hydrogen form similar monolayers, but on Fe oxygen forms several layers of oxide. On Rh, Mo and possibly Ta the fast CO chemisorption corresponds to a two-site mechanism; on W and Fe it lies between that for a single and a two-site mechanism; on Pt and Pd single-site adsorption may take place. Kinetics of slow oxygen uptakes have been followed on Rh, Mo, W, Ta, Fe, Cu and Zn. With Rh, Mo, W, Ta and Zn it is believed that formation of the first oxide layer has been observed, and the rate expression is velocity ∝√{ p ) e -∝ v / RT , where v is the adsorbed volume and ∝ is a constant. The suggested mechanism is interchange of adsorbed oxygen atoms with underlying metal atoms, whereby metal atoms are exposed for further oxygen adsorption. On Cu and Fe formation of up to six and ten oxide layers respectively have been observed, and the rate expressions (u ∝ p 0.75 / v 2 and u ∝ p 0.2 e ∝'/ v ) have been interpreted in terms of the theory of Cabrera & Mott (1948).

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[O32] Thermodynamics and kinetics of interfacial interactions between oxide layer on a steel surface and liquid Na2O- SiO2- B2O3- TiO2 glass

Calphad ◽

10.1016/j.calphad.2015.01.039 ◽

2015 ◽

Vol 51 ◽

pp. 355

Author(s):

Rayisa Voytovych ◽

Fiqiri Hodaj ◽

Marie-José Cornu ◽

Alexey Koltsov ◽

Cécile Pesci

Keyword(s):

Oxide Layer ◽

Steel Surface ◽

Interfacial Interactions ◽

Thermodynamics And Kinetics ◽

Kinetics Of

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Kinetics of Ethylene/1-Hexene Copolymerization over a Single-Site Hafnium Bis(phenolate) Catalyst: Insights into Insertion Complexity and Deactivation Pathways

Macromolecules ◽

10.1021/acs.macromol.1c00230 ◽

2021 ◽

Author(s):

Chan Y. Park ◽

Jeffrey M. Switzer ◽

Joshua Speer ◽

Grigori A. Medvedev ◽

James M. Caruthers ◽

...

Keyword(s):

Single Site ◽

Kinetics Of

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On the kinetics of oxygen adsorption over stepped Pt surface

Reaction Kinetics and Catalysis Letters ◽

10.1007/bf02066955 ◽

1995 ◽

Vol 56 (1) ◽

pp. 97-105 ◽

Cited By ~ 2

Author(s):

V. I. Savchenko ◽

N. I. Efremova

Keyword(s):

Oxygen Adsorption ◽

Kinetics Of

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Characterization of an endothelin ET(B) receptor in the gill of the dogfish shark Squalus acanthias

Journal of Experimental Biology ◽

10.1242/jeb.202.24.3605 ◽

1999 ◽

Vol 202 (24) ◽

pp. 3605-3610 ◽

Cited By ~ 3

Author(s):

D.H. Evans ◽

M.P. Gunderson

Keyword(s):

Blood Vessels ◽

Gill Tissue ◽

Squalus Acanthias ◽

Single Site ◽

Acid Base Balance ◽

Ion Regulation ◽

Base Balance ◽

Dogfish Shark ◽

Kinetics Of

Endothelins (ETs) are potent vasoconstrictive peptides that are secreted by the vascular endothelium and other tissues in vertebrates. Previous studies have demonstrated that ETs are expressed in a variety of fish tissues and contract various blood vessels. In order to determine if receptors for ET are expressed in fish gill tissue, we examined the binding kinetics of (125)I-labeled, human ET-1 to membrane fragments isolated from the gill of the dogfish shark, Squalus acanthias. (125)I-ET-1 bound at a single site, with a dissociation constant (K(d)) and binding site number (B(max)) very similar to those described in a variety of mammalian blood vessels. ET-1 and ET-3 competed equally with (125)I-ET-1, suggesting that the receptor was ET(B), which has been shown in mammalian systems to bind to both ligands equally. The ET(B)-specific agonists sarafotoxin S6c, IRL-1620, and BQ-3020 also competed against (125)I-ET-1 at a single site, supporting this hypothesis. We conclude that the shark gill expresses an ET(B) receptor with substantial homology to the mammalian receptor and that ET may play an important role in modulating such vital gill functions as gas exchange, ion regulation, acid-base balance, and excretion of nitrogen.

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A Nonvolatile MOSFET Memory Device Based on Mobile Protons in the Gate Dielectric

MRS Proceedings ◽

10.1557/proc-510-463 ◽

1998 ◽

Vol 510 ◽

Author(s):

K. Vanheusden ◽

W.L. Warren ◽

D.M. Fleetwood ◽

R.A.B. Devine ◽

B.L. Draper ◽

...

Keyword(s):

Oxide Layer ◽

Hydrogen Diffusion ◽

Gate Dielectric ◽

Memory Device ◽

Flat Band ◽

Generation Process ◽

Alkali Ions ◽

Non Volatile Memory ◽

Volatile Memory ◽

Kinetics Of

AbstractEver since the introduction of the metal-oxide-silicon field-effect-transistor (MOSFET), the nature of mobile and trapped charge in the oxide layer has been studied in great detail. For example, contamination with alkali ions such as sodium, causing instability of the flat-band voltage, was a major concern in the early days of MOS fabrication. Another SiO2 impurity of particular interest is hydrogen, because of its beneficial property of passivating charge traps. In this work we show that annealing of Si/SiO2/Si structures in forming gas (Ar:H2; 95:5) above 400 °C can introduce mobile H+ ions into the SiO2 layer. These mobile protons are confined within the oxide layer, and their space-charge distribution is well controllable and easily rearrangeable by applying a gate bias, making them potentially useful for application in a reliable nonvolatile MOSFET memory device. We present speed, retention, endurance, and radiation tolerance data showing that this non-volatile memory technology can be competitive with existing Si-based non-volatile memory technologies such as Flash.The chemical kinetics of mobile-proton reactions in the SiO2 film are also analyzed in greater detail. Our data show that the initial buildup of mobile protons during hydrogen annealing is limited by the rate of lateral hydrogen diffusion into the buried SiO2 films. The final density of mobile protons is determined by the cooling rate which terminates the annealing process and, in the case of subsequent anneals, by the temperature of the final anneal. To explain the observations, we propose a dynamical equilibrium model. Based on these insights, the incorporation of the proton generation process into standard semiconductor process flows is discussed.

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Energetics and kinetics of Cu atoms and clusters on the Si(111)-7 × 7 surface: first-principles calculations

Physical Chemistry Chemical Physics ◽

10.1039/c6cp01919f ◽

2016 ◽

Vol 18 (27) ◽

pp. 18549-18554 ◽

Cited By ~ 2

Author(s):

Xiao-Yan Ren ◽

Chun-Yao Niu ◽

Wei-Guang Chen ◽

Ming-Sheng Tang ◽

Jun-Hyung Cho

Keyword(s):

Thin Film ◽

Crystal Growth ◽

First Principles ◽

Self Assembly ◽

Catalytic Reactions ◽

Semiconductor Surface ◽

First Principles Calculations ◽

Metal Atoms ◽

Thin Film Epitaxy ◽

Kinetics Of

Exploring the properties of noble metal atoms and nano- or subnano-clusters on the semiconductor surface is of great importance in many surface catalytic reactions, self-assembly processes, crystal growth, and thin film epitaxy.

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KINETIC STUDIES OF METHYL-BIS-β-CHLOROETHYLAMINE: III. THE KINETICS OF THE DIMERIZATION IN METHANOL

Canadian Journal of Research ◽

10.1139/cjr48b-018 ◽

1948 ◽

Vol 26b (2) ◽

pp. 175-180 ◽

Cited By ~ 2

Author(s):

C. A. Winkler ◽

A. W. Hay ◽

A. L. Thompson

Keyword(s):

Rate Constants ◽

Initial Rate ◽

Kinetic Studies ◽

First Order ◽

Rate Expression ◽

Principal Reaction ◽

Kinetics Of ◽

Rate Controlling Step

The principal reaction of methyl-bis-β-chloroethylamine in methanol is dimerization, which results in one chlorine from each molecule becoming ionic, but this is accompanied by slight alcoholysis. The rate-controlling step is believed to be the first order formation of an ethylenimonium ion which reacts rapidly with one of its kind to form dimer. The rate expression as calculated from initial rate constants is k (initial) = 4.0 × 1013e−19600/RThr.−1.

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