The role of the diffusion process in bimolecular reactions with neighborhood

2020 ◽  
Author(s):  
José Cândido Souza Filho ◽  
Alejandro López‐Castillo
Keyword(s):  
Diffusion Process ◽  
Bimolecular Reactions

Justify role of Similarity Diffusion Process in cross-media topic ranking: an empirical evaluation

2017 ◽  
Vol 76 (23) ◽  
pp. 25145-25157 ◽  
Author(s):  
Junbiao Pang ◽  
Jing Huang ◽  
Weigang Zhang ◽  
Qingming Huang ◽  
Baocai Yin
Keyword(s):  
Diffusion Process ◽  
Empirical Evaluation ◽  
Cross Media

A Re-Appraisal of Cavity Growth Processes in Superplasticity

1990 ◽  
Vol 196 ◽  
Author(s):  
Yan Ma ◽  
Terence G. Langdon
Keyword(s):  
Grain Size ◽  
Grain Boundary ◽  
Diffusion Process ◽  
Superplastic Deformation ◽  
Cavity Growth ◽  
Normal Model ◽  
Experimental Conditions ◽  
Diffusion Growth ◽  
New Model

ABSTRACTIt is well known that cavities are nucleated and grow during the superplastic deformation of many materials. The various theories for cavity growth are examined with special emphasis on the role of growth by diffusion. It is demonstrated that the normal model for the diffusion growth of cavities is inadequate for superplastic materials when the grain boundary lengths are very small. By developing a new model for the growth of an isolated cavity to sizes exceeding the grain size, it is shown that the diffusion process may play a major role in cavity growth under a range of experimental conditions.

ON THE ROLE OF KINKS AND STRAIN IN HETEROEPITAXIAL GROWTH: AN STM STUDY

2000 ◽  
Vol 07 (05n06) ◽  
pp. 673-677
Author(s):  
E. LUNDGREN ◽  
M. SCHMID ◽  
G. LEONARDELLI ◽  
A. HAMMERSCHMID ◽  
B. STANKA ◽  
...  
Keyword(s):  
Diffusion Process ◽  
Scanning Tunneling Microscopy ◽  
Three Dimensional ◽  
Growth Mode ◽  
Scanning Tunneling ◽  
Two Dimensional ◽  
Heteroepitaxial Growth ◽  
Tunneling Microscopy ◽  
Exchange Diffusion

Interlayer diffusion of Co over steps of vacancy islands on the Pt(111) surface as studied by scanning tunneling microscopy is presented. It is demonstrated that Co atoms descend Pt steps by an exchange diffusion process at the step edge with the Pt atoms. Further, the exchange diffusion process is observed to occur at the corners (kinks) of the vacancy islands. The importance of kinks concerning whether the growth mode of a heteropitaxial film is two-dimensional or three-dimensional is demonstrated for the case of thin Co films on Pt(111). We argue that the strain in the Co film is to a large extent responsible for the kink formation.

An Atomic View of Surface Diffusion on Metals

1985 ◽  
Vol 57 ◽  
Author(s):  
Gert Ehrlich
Keyword(s):  
Diffusion Process ◽  
Metal Surfaces ◽  
Mean Square Displacement ◽  
Surface Transport ◽  
Specific Effects ◽  
Metal Atoms ◽  
The Status ◽  
Considerable Detail ◽  
Field Ion Microscope

AbstractAtomic migration in crystals is obscured by the crystal itself, and it has therefore taken ingenious indirect methods to study the diffusion process. In contrast, diffusion at surfaces is amenable to fairly direct examination, on the atomic level, through the use of the field-ion microscope. By combining measurements of the mean-square displacement with determinations of the distance distribution function, considerable detail about atomic jumps in diffusion can be obtained. Here we will briefly review results obtained by field-ion microscopic examination of single metal atoms and metal clusters diffusing on metal crystals.What is noteworthy in the diffusion of single metal atoms is the variety of behavior which is dictated by the nature of the substrate, and the occasional complexity of the diffusion process. Examples of substrate-specific effects in atomic migration will be given for both fcc and bcc metals. Another surprising aspect of diffusion on metal surfaces is the role of clusters. These are stable at relatively high temperatures, and often diffuse at rates comparable to those of single atoms. The status of such cluster studies will be briefly examined, not only for their significance in surface transport, but also for their interest in understanding cohesion at metal surfaces.

EFFECT OF DIFFUSION PROCESS ON COATING IN HOT-DIPPED ALUMINIZED STEEL

2019 ◽  
Vol 26 (10) ◽  
pp. 1950070
Author(s):  
YUWEN DING ◽  
XIAOCHUN CHEN ◽  
YA LIU ◽  
XUPING SU
Keyword(s):  
Corrosion Resistance ◽  
Diffusion Process ◽  
Diffusion Path ◽  
X Ray Diffraction ◽  
X Ray ◽  
Intermetallic Coating ◽  
Diffusion Treatment ◽  
Aluminized Steel ◽  
And Diffusion

Aluminized steels possess excellent corrosion resistance due to the formation of Al-Fe solution phases and intermetallic compounds in coatings. Ni was added to baths to further improve the corrosion resistance of the coatings at high temperature. Here, the role of Ni in the formation of coatings and the effect of diffusion process on the developing of coatings were investigated. 45 steels were immersed in Al-Ni baths (Al-1mass% Ni, Al-3mass% Ni, and Al-5mass% Ni) and diffusion-treated at 1023 and 1123[Formula: see text]K for 20, 40 and 100[Formula: see text]min, respectively. The coatings of samples were analyzed via scanning electron microscopy (SEM) along with energy-dispersive X-ray spectroscopy (EDS). X-ray diffraction (XRD) was further used to confirm the types of phases that formed during diffusion treatment. The formations of intermetallic coating layers were also analyzed via the diffusion path. More continuous Al3Ni layer and compact coating were obtained with diffusion treatment at 1023[Formula: see text]K for 40[Formula: see text]min.

Worldwide Diffusion of E-Parliament within the Framework of Policy Transfer

2012 ◽  
pp. 51-62
Author(s):  
Mehmet Zahid Sobaci
Keyword(s):  
Diffusion Process ◽  
Conceptual Framework ◽  
Case Studies ◽  
Policy Transfer ◽  
International Level ◽  
Big Picture ◽  
The Way

The aim of this chapter is to analyze the worldwide diffusion of e-parliament and the role played by the Global Centre for ICT in Parliament (GCIP), within the framework of policy transfer. There are two main reasons why it is necessary to focus on the role of GCIP in the diffusion of e-parliament: 1) The GCIP is one of the most active actors in this process; and 2) Activities undertaken by the GCIP and its relations with its partners give important clues about the big picture of e-parliament transfer at the international level. In the analysis of worldwide diffusion process of e-parliament in this study, policy transfer literature is used. This chapter goes beyond the conceptual framework and case studies pave the way for the evaluation of e-parliament from a different perspective by focusing on the transfer of e-parliament as an innovation.

Electrons in fluids: the role of disorder

1977 ◽  
Vol 55 (11) ◽  
pp. 1906-1915 ◽  
Author(s):  
Morrel H. Cohen
Keyword(s):  
General Theory ◽  
Diffusion Process ◽  
Molecular Motion ◽  
Localization Length ◽  
Liquid Argon ◽  
Disordered Materials ◽  
Characteristic Frequencies ◽  
Disordered Solids ◽  
Slow Electrons

I review the present status of the theory of those aspects of the theory of disordered materials which are particularly relevant to the physics of electrons in fluids. First, however, I describe a general theory of the movement of slow electrons in fluids of arbitrary complexity in which the fluid is treated as a fluctuating medium. Coupling to the fluctuations is via a set of generalized deformation potentials. It is shown that this concept permits a way out of the impasse that has been reached in understanding the mobility of slow electrons in liquid argon via Lekner's theory. Assuming that molecular motion can be neglected on the electronic time scale permits taking over various relevant results from the theory of electrons in disordered solids, which is briefly reviewed. The effect of molecular motion is studied next. It is shown that strict localization does not occur and that the quasi-localized electrons diffuse with a characteristic correlation frequency depending on electron–molecule coupling and upon the characteristic frequencies of molecular motion as well as with a correlation length related to the localization length in static problems. Under easily reached conditions, this diffusion process is faster than that giving rise to the Stokes law mobility. Finally, a discussion is given of mobility transitions in which localization by disorder is distinguished from self-trapping.

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