Atomic-level mechanism of the effects of NOx species on Pb adsorption over the Al2O3 sorbent surface

2021 ◽  
Vol 570 ◽  
pp. 151217
Author(s):  
Aijia Zhang ◽  
Yingju Yang ◽  
Jing Liu ◽  
Yingni Yu ◽  
Junyan Ding ◽  
...  
Keyword(s):  
Author(s):  
William Krakow

In recent years electron microscopy has been used to image surfaces in both the transmission and reflection modes by many research groups. Some of this work has been performed under ultra high vacuum conditions (UHV) and apparent surface reconstructions observed. The level of resolution generally has been at least an order of magnitude worse than is necessary to visualize atoms directly and therefore the detailed atomic rearrangements of the surface are not known. The present author has achieved atomic level resolution under normal vacuum conditions of various Au surfaces. Unfortunately these samples were exposed to atmosphere and could not be cleaned in a standard high resolution electron microscope. The result obtained surfaces which were impurity stabilized and reveal the bulk lattice (1x1) type surface structures also encountered by other surface physics techniques under impure or overlayer contaminant conditions. It was therefore decided to study a system where exposure to air was unimportant by using a oxygen saturated structure, Ag2O, and seeking to find surface reconstructions, which will now be described.


Author(s):  
H. Kinney ◽  
M.L. Occelli ◽  
S.A.C. Gould

For this study we have used a contact mode atomic force microscope (AFM) to study to topography of fluidized cracking catalysts (FCC), before and after contamination with 5% vanadium. We selected the AFM because of its ability to well characterize the surface roughness of materials down to the atomic level. It is believed that the cracking in the FCCs occurs mainly on the catalysts top 10-15 μm suggesting that the surface corrugation could play a key role in the FCCs microactivity properties. To test this hypothesis, we chose vanadium as a contaminate because this metal is capable of irreversibly destroying the FCC crystallinity as well as it microporous structure. In addition, we wanted to examine the extent to which steaming affects the vanadium contaminated FCC. Using the AFM, we measured the surface roughness of FCCs, before and after contamination and after steaming.We obtained our FCC (GRZ-1) from Davison. The FCC is generated so that it contains and estimated 35% rare earth exchaged zeolite Y, 50% kaolin and 15% binder.


1996 ◽  
Vol 6 (7) ◽  
pp. 825-829 ◽  
Author(s):  
M. Karlík ◽  
B. Jouffrey
Keyword(s):  

2006 ◽  
Vol 58 ◽  
pp. 157-172 ◽  
Author(s):  
Edna Ullmann-Margalit

I want to focus on some of the limits of decision theory that are of interest to the philosophical concern with practical reasoning and rational choice. These limits should also be of interest to the social-scientists' concern with Rational Choice.Let me start with an analogy. Classical Newtonian physics holds good and valid for middle-sized objects, but not for the phenomena of the very little, micro, sub-atomic level or the very large, macro, outer-space level: different theories, concepts and laws apply there. Similarly, I suggest that we might think of the theory of decisionmaking as relating to middle-sized, ordinary decisions, and to them only. There remain the two extremes, the very ‘small’ decisions on the one hand and the very ‘big’ decisions on the other. These may pose a challenge to the ordinary decision theory and may consequently require a separate treatment.


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