scholarly journals Reducibility of Metal Oxides in Hydrogen and Strength of Oxygen Bond in Their Surface Layer

1990 ◽  
Vol 63 (2) ◽  
pp. 590-591 ◽  
Author(s):  
D. Klissurski ◽  
R. Dimitrova
Keyword(s):  
Surface Layer ◽  
Metal Oxides ◽  
Oxygen Bond

Calorimetric study of oxygen bond strength in the surface layer of manganese dioxide

1977 ◽  
Vol 7 (2) ◽  
pp. 133-137
Author(s):  
Yu. D. Pankratiev ◽  
V. M. Turkov ◽  
M. Forissier ◽  
J. L. Portefaix
Keyword(s):  
Surface Layer ◽  
Bond Strength ◽  
Manganese Dioxide ◽  
Calorimetric Study ◽  
Oxygen Bond

MONTE CARLO SIMULATION OF THE ADSORBATE- ASSISTED ADSORPTION IN THE CASE OF CO/ZnO

2001 ◽  
Vol 08 (03n04) ◽  
pp. 353-360 ◽  
Author(s):  
U. BURGHAUS
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Surface Layer ◽  
Metal Oxides ◽  
Gas Phase ◽  
Surface Coverage ◽  
Adsorption Dynamics ◽  
Polar Surfaces

Recently, a detailed study of the adsorption dynamics of CO on metal oxides, i.e. for the polar ZnO surfaces, has been published [Becker et al., JCP113, 6334 (2000)]. For both polar surfaces, an increase in the adsorption probabilities with increasing surface coverage (adsorbate-assisted adsorption) has been observed. A Monte Carlo (MC) version of the so-called modified Kisliuk model is presented, which accounts for the main features observed experimentally. The model, which includes two fit parameters, is based on the differences in the mass differences in the mass mismatch of the gas phase species and the surfaces. Therefore, in particular, the polar surfaces of ZnO, which differ by the mass of the atoms in the first surface layer, are perfectly suited for discussing the proposed MC algorithm.

A New Silver-Based Graded Composite as Electrical Contact Material

2007 ◽  
Vol 336-338 ◽  
pp. 2616-2618 ◽  
Author(s):  
Lu Wang ◽  
Yong Zhao ◽  
X.T. Zhu ◽  
Y. Wang
Keyword(s):  
Surface Layer ◽  
Metal Oxides ◽  
Contact Surface ◽  
Electrical Contact ◽  
Functionally Graded ◽  
Operating Parameters ◽  
Contact Material ◽  
Contact Materials ◽  
Electrical Contact Material ◽  
Graded Material

Silver metal oxides (Ag/MeO) are extensively used as electrical contact materials in switching systems. A contact material with ideal operating parameters is very difficultly fabricated by conventional manufacturing techniques. In this paper, a new electrical contact material characterized by graded distributions of different oxides in Ag matrix was fabricated in order to optimize the distributions of operating parameters in material bulk instead of to enhance synchronously properties of that on contact surface. Two selected metal oxides, NiO and SnO2, were doped into Ag matrices, of which one surface layer NiO 12wt% was doped and another SnO2 12wt%, and the concentrations of NiO and SnO2 were varied gradually in bulk. The electrical contact test results show that the average operating number of NiO doped surface layer of graded Ag composite as contact surface is 4600 under 20A current and 220V AC voltage without melted welding while that of samples doped uniformly with NiO is 2200 under the same testing conditions. However, the average loss of mass due to arc erosion of graded samples is higher than that of uniform samples. We conclude that the functionally graded material (FGM) concept has potential application for electric contact materials.

scholarly journals ELECTROMAGNETIC RADIATION REFLECTION AND TRANSMISSION CHARACTERISTICS OF TWO-LAYER STRUCTURES BASED ON TRANSITION METAL OXIDES

Doklady BGUIR ◽  
2019 ◽  
pp. 93-100
Author(s):  
O. V. Boiprav ◽  
N. V. Bogush ◽  
L. M. Lynkou
Keyword(s):  
Surface Layer ◽  
Transition Metal ◽  
Metal Oxides ◽  
Electromagnetic Radiation ◽  
Transition Metal Oxides ◽  
Reflection And Transmission Coefficients ◽  
Frequency Range ◽  
Reflection And Transmission ◽  
Transmission Coefficients ◽  
Layer Structures

The aim of the work, the results of which are presented in the framework of the article, was to study the of electromagnetic radiation interaction laws in the frequency range 0.7…17 GHz with two-layer structures, the surface layer of which was made using powdered titanium dioxide, and the inner layer was made using a powder material based on oxide ferric iron. The thickness of the layers of the studied structures varied from 0.3 to 1 cm. To achieve this goal, theobjectives associated with the development of a methodology for the manufacture of multilayer structures based on composite materials containing transition metal oxides, as well as with the measurement of such structures samples electromagnetic radiation reflection and transmission coefficients in the frequency range 0.7...17 GHz. These measurements were carried out using a panoramic meter of reflection and transmission coefficients SNA 0.01–17. Based on the obtained measurement results, it was shown that in the frequency range 0.7…2 GHz, the lowest values of electromagnetic radiation reflection coefficient, reaching –20 dB, are characterized by structures whose surface layer thickness is 1 cm, and in the range 2 ... 17 GHz – structures, thickness the surface layer of which is 0.5 or 1 cm (depending on the thickness of the inner layer). The values of electromagnetic radiation transmission coefficient in the frequency range of 0.7...17 GHz of such structures reach –23 dB. Based on the results of the study, it is proposed to use the considered structures in the process of creating shielded rooms or improving the latter (for example, in cases, when it's necessary to reduce the level of passive interference in rooms shielded with metal materials).

The oxidation of Inconel alloy MA754 at low oxidation potential

1983 ◽  
Vol 41 ◽  
pp. 218-219
Author(s):  
D. N. Braski ◽  
P. D. Goodell ◽  
J. V. Cathcart ◽  
R. H. Kane
Keyword(s):  
Surface Layer ◽  
Oxidation Potential ◽  
Metal Interface ◽  
Elevated Temperature Strength ◽  
Surface Conditions ◽  
Inconel Alloy ◽  
Inco Alloy ◽  
Resistance To Oxidation ◽  
Oxide Particles ◽  
Cold Worked

It has been known for some time that the addition of small oxide particles to an 80 Ni—20 Cr alloy not only increases its elevated-temperature strength, but also markedly improves its resistance to oxidation. The mechanism by which the oxide dispersoid enhances the oxidation resistance is being studied collaboratively by ORNL and INCO Alloy Products Company.Initial experiments were performed using INCONEL alloy MA754, which is nominally: 78 Ni, 20 Cr, 0.05 C, 0.3 Al, 0.5 Ti, 1.0 Fe, and 0.6 Y2O3 (wt %).Small disks (3 mm diam × 0.38 mm thick) were cut from MA754 plate stock and prepared with two different surface conditions. The first was prepared by mechanically polishing one side of a disk through 0.5 μm diamond on a syntron polisher while the second used an additional sulfuric acid-methanol electropolishing treatment to remove the cold-worked surface layer. Disks having both surface treatments were oxidized in a radiantly heated furnace for 30 s at 1000°C. Three different environments were investigated: hydrogen with nominal dew points of 0°C, —25°C, and —55°C. The oxide particles and films were examined in TEM by using extraction replicas (carbon) and by backpolishing to the oxide/metal interface. The particles were analyzed by EDS and SAD.

Structural analysis of the surface-layer protein of spirillum serpens by high-resolution electron microscopy

1983 ◽  
Vol 41 ◽  
pp. 738-739
Author(s):  
W. H. Wu ◽  
R. M. Glaeser
Keyword(s):  
Electron Microscopy ◽  
Surface Layer ◽  
Structural Analysis ◽  
High Resolution ◽  
Low Dose ◽  
High Resolution Electron Microscopy ◽  
Optical Diffraction ◽  
Surface Layer Protein ◽  
Morphological Unit ◽  
Resolution Electron

Spirillum serpens possesses a surface layer protein which exhibits a regular hexagonal packing of the morphological subunits. A morphological model of the structure of the protein has been proposed at a resolution of about 25 Å, in which the morphological unit might be described as having the appearance of a flared-out, hollow cylinder with six ÅspokesÅ at the flared end. In order to understand the detailed association of the macromolecules, it is necessary to do a high resolution structural analysis. Large, single layered arrays of the surface layer protein have been obtained for this purpose by means of extensive heating in high CaCl2, a procedure derived from that of Buckmire and Murray. Low dose, low temperature electron microscopy has been applied to the large arrays.As a first step, the samples were negatively stained with neutralized phosphotungstic acid, and the specimens were imaged at 40,000 magnification by use of a high resolution cold stage on a JE0L 100B. Low dose images were recorded with exposures of 7-9 electrons/Å2. The micrographs obtained (Fig. 1) were examined by use of optical diffraction (Fig. 2) to tell what areas were especially well ordered.

Electron-Mirror Microscopic Aspects of Ferroelectric Domains of BaTiO3 And Ca2Sr (C2H5CO2)6

1970 ◽  
Vol 28 ◽  
pp. 478-479
Author(s):  
Teruo Someya ◽  
Jinzo Kobayashi
Keyword(s):  
Surface Layer ◽  
Electric Fields ◽  
Quantitative Study ◽  
Recent Progress ◽  
Ferroelectric Domain ◽  
Resolving Power ◽  
Surface Pattern ◽  
Crystal Surfaces ◽  
One Dimensional ◽  
Ferroelectric Domains

Recent progress in the electron-mirror microscopy (EMM), e.g., an improvement of its resolving power together with an increase of the magnification makes it useful for investigating the ferroelectric domain physics. English has recently observed the domain texture in the surface layer of BaTiO3. The present authors ) have developed a theory by which one can evaluate small one-dimensional electric fields and/or topographic step heights in the crystal surfaces from their EMM pictures. This theory was applied to a quantitative study of the surface pattern of BaTiO3).

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