Hydrogenation of 2-phenyl-1-propene and 1-hexene on platinum black surface modified by Pb, Tl and Bi atoms

1982 ◽  
Vol 47 (4) ◽  
pp. 1222-1228 ◽  
Author(s):  
Ivo Paseka ◽  
Libor Červený ◽  
Dagmar Šmigolová ◽  
Vlastimil Růžička
Keyword(s):  
Organic Substance ◽  
Platinum Black ◽  
Hydrogenation Rate ◽  
Low Degree ◽  
Modified Surfaces ◽  
Black Surface ◽  
Surface Modified

Hydrogenation of 2-phenyl-1-propene and 1-hexene in ethanol, toluene and benzene was studied on platinum black modified by ad-atoms of lead, thallium, and bismuth. The experimental dependences of the specific hydrogenation rate on the degree of coverage by the metal ad-atoms are interpreted under the assumption that the substrate and hydrogen take part in the reaction and at low degree of the coverage, the organic substance is adsorbed on the modified and non-modified surfaces to the same extent.

scholarly journals Development of a Novel Resistance Heating System for Microforming Using Surface-Modified Dies and Evaluation of Its Heating Property

Metals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 440
Author(s):  
Ming Yang ◽  
Tetsuhide Shimizu
Keyword(s):  
Electrical Properties ◽  
Compression Test ◽  
Stress Reduction ◽  
Electrical Resistance ◽  
Heating System ◽  
Resistance Heating ◽  
Heating Efficiency ◽  
Coated Tools ◽  
Modified Surfaces ◽  
Surface Modified

For this study, a novel resistance heating system for microforming was developed using surfaces of forming dies as heating resources. The electrical resistance of the die surfaces was designed and the hard-coating material AlCrSiN was selected to coat the die surfaces for heating. To clarify the effects of the thickness and modified surfaces on heating efficiency, the temperature and stress reduction were evaluated in a micro-compression test using dies coated with 0.5 and 1 μm AlCrSiN films. Furthermore, the formability was also demonstrated using 1 μm thick AlCrSiN-coated tools in a microforging test. By applying surface-modified dies to the forming processes, we found that not only was the heating efficiency improved, but also the dependence of heating on the product’s shape and the material’s electrical properties was reduced.

Corrosion Characteristics of Surface-Modified DET Magnesium Powders

2004 ◽  
Vol 449-452 ◽  
pp. 369-372
Author(s):  
W.S. Chung ◽  
W.Y. Yoon ◽  
Kwang Jin Kim
Keyword(s):  
Corrosion Resistance ◽  
Surface Layer ◽  
Current Density ◽  
Nacl Solution ◽  
Composition Distribution ◽  
Passive Behavior ◽  
Modified Surfaces ◽  
Modified Surface ◽  
Surface Modified ◽  
Modified Surface Layer

Magnesium powders having inactive surface layer have been processed easily and intentionally by DET under fluoride, chromate, and bromide salt. The modified surfaces play an important role in preventing contact with active environments to improve corrosion resistance of Magnesium powders; the image of the surface modified powders was observed using SEM. The composition distribution and characteristics was determined and analyzed by using XRD, XPS, and EIS. Compared with bare Magnesium, the Magnesium having chromate modified surface layer showed a more passive behavior such as smaller current density and nobler potential in 4wt% NaCl solution.

Hydrogenation of 2-phenyl-1-propene on platinum black modified with copper

1980 ◽  
Vol 45 (12) ◽  
pp. 3541-3545
Author(s):  
Ivo Paseka ◽  
Libor Červený ◽  
Josef Mach ◽  
Vlastimil Růžička
Keyword(s):  
Reaction Rate ◽  
Surface Coverage ◽  
Platinum Black ◽  
Hydrogenation Rate ◽  
Platinum Surface ◽  
Adsorption Sites ◽  
Pt Black

Copper deposited from a solution of copper(II) formate on Pt-black at surface coverage lower than unity is present on the platinum surface both in the form of ad-atoms and in the form of multiatomic layers. From the dependence of the hydrogenation rate on coverage by copper is followed that the reaction rate depended on the number of free pairs of the adsorption sites of platinum unoccupied by copper.

scholarly journals A new method of determining the radiation constant

1912 ◽  
Vol 86 (585) ◽  
pp. 180-196 ◽  
Keyword(s):  
Black Body ◽  
Absolute Temperature ◽  
Absolute Zero ◽  
New Method ◽  
Platinum Black ◽  
Main Current ◽  
First Case ◽  
Black Surface ◽  
The Absolute

According to stefan's law the rate of radiation of energy from a full radiator in surroundings at a temperature of absolute zero is σ θ 4 ergs per cm. 2 per sec., where θ is the absolute temperature of the radiator. If the radiator be in surroundings which are themselves full radiators, but at absolute temperature θ 1 , the rate of loss of energy by radiation is taken to be σ( θ 4 - θ 1 4 ). The classical determination of the constant σ is due to Kurlbaum, who used a surface bolometer with a platinum-black surface. The rise of temperature of the bolometer when exposed to the radiation from an approximately full radiator or "black body" was observed. The radiation was then cut off, and an equal rise of temperature was produced by increasing the main current in the bolometer. It was assumed that the energy received per second from the radiator in the first case was equal to the energy received per second from the increase of current in the second ease. The resulting value of σ was 5·33 x 10 -5 ergs per cm. 2 per sec. per deg. 4 , or 5·33 x 10 -12 watts per cm. 2 per deg. 4 .

Analytical Electron Microscopy of Surface-Modified Ceramics

1985 ◽  
Vol 43 ◽  
pp. 276-279
Author(s):  
P. S. Sklad
Keyword(s):  
Electron Microscopy ◽  
Analytical Electron Microscopy ◽  
Theoretical Models ◽  
Ceramic Materials ◽  
Solute Concentration ◽  
Second Phase ◽  
Analytical Electron ◽  
Implantation Techniques ◽  
Lattice Damage ◽  
Surface Modified

Over the past several years, it has become increasingly evident that materials for proposed advanced energy systems will be required to operate at high temperatures and in aggressive environments. These constraints make structural ceramics attractive materials for these systems. However it is well known that the condition of the specimen surface of ceramic materials is often critical in controlling properties such as fracture toughness, oxidation resistance, and wear resistance. Ion implantation techniques offer the potential of overcoming some of the surface related limitations.While the effects of implantation on surface sensitive properties may be measured indpendently, it is important to understand the microstructural evolution leading to these changes. Analytical electron microscopy provides a useful tool for characterizing the microstructures produced in terms of solute concentration profiles, second phase formation, lattice damage, crystallinity of the implanted layer, and annealing behavior. Such analyses allow correlations to be made with theoretical models, property measurements, and results of complimentary techniques.

Assessment of Damage to Human Platelets after Aggregation and Other Injuries by Microscopic Observation and Estimation of Serotonin Uptake

1970 ◽  
Vol 23 (02) ◽  
pp. 261-275 ◽  
Author(s):  
G Zbinden ◽  
J. N Mehrishi ◽  
S Tomlin
Keyword(s):  
Platelet Aggregation ◽  
Electrophoretic Mobility ◽  
Human Platelets ◽  
Freezing And Thawing ◽  
Low Degree ◽  
Microscopic Evaluation ◽  
Negative Surface ◽  
Negative Surface Charge ◽  
Charged Macromolecules ◽  
5 Ht Uptake

SummaryThe severity of platelet damage induced by hyper- and hypotonic NaCl solutions and freezing and thawing was assessed by microscopic evaluation and measuring inhibition of 5-HT uptake. The same techniques were used to quantitate the effects of aggregating agents. The positively charged macromolecules PS, Poly-L und Poly-O reduced the net negative surface charge as determined by microelectrophoresis, caused platelet aggregation and inhibited 5-HT uptake. The damaging effects of Poly-L and Poly-O were more severe and more closely related to concentration than that of PS. The negatively charged macromolecules Poly-IC and NaPS increased the anodic electrophoretic mobility. Poly-IC and heparin caused a low degree of platelet clumping and no inhibition of 5-HT uptake. NaPS produced severe platelet damage with extensive clumping and complete inhibition of 5-HT uptake. Na laurate had the same effect, but did not alter electrophoretic mobility. ADP caused concentration-dependent platelet aggregation and inhibition of 5-HT uptake. The effects of ADP and NaPS were compared in agitated and non-agitated platelet samples containing identical concentrations of the 2 compounds. Agitation was found to increase the degree of platelet clumping and to reduce 5-HT uptake.

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