Papers by Keyword: Reaction

Abstract: Low energy electron diffraction (LEED), Auger electron spectroscopy (AES) and scanning tunnelling microscopy (STM) were used to study the reactive diffusion of one monolayer of silicon deposited at room temperature onto a Ni (111) substrate. We have done isochronal and isothermal kinetics by AES, and we observed in both cases a kinetics blockage on a plateau corresponding to around one third of a silicon monolayer. STM images and LEED patterns both recorded at room temperature just after annealing, reveal formation of an ordered hexagonal superstructure corresponding probably to a two-dimensional surface silicide.

Abstract: Nanoscale systems show a wide variety of physical properties that cannot be observed in the bulk. Using atom probe tomography, it is possible to study nanostructured materials with almost atomic resolution in all three dimensions. In this article, we will present a short review of the latest atom-probe measurements carried out at University of Münster with particular focus on diffusion and segregation measurements in triple junctions and interface analysis.

Abstract: In this paper, density functional theory calculation combined with period slab models were used to investigate the interaction between fuel gas CO and different active site in Mn3O4(001) surface, the formation of bidentate carbonate species, the breakage of old bond along with generation of new bond in CO oxidation process. Different adsorption sites in both Mn terminal and Mn-O terminal was discussed. Results showed that the tetrahedral Mn top site was the favorite adsorption site on the Mn terminal surface with the bonding energy of 1.011eV, while CO bond to the O atom of Mn-O-terminal surface to form a new C-O bond leading to the generation of the bidentate carbonate species. Further, Complete LST/QST method was used to detect the path of generation reaction of CO2 molecular, which predicted activation energy of 0.96eV. The results will promote the fundamental understanding and applications of Mn-based oxygen carrier.

Abstract: The interdiffusion behaviors and interfacial reaction in solid Cu/solid Ni, liquid Bi/solid Bi_0.4Sb_0.6, liquid Al/solid Cu, and gas Al/solid Cu diffusion couples have been experimentally studied under a high magnetic field of up to 12T. The effects of magnetic flux density and the direction of magnetic field (B) on the evolution of interfacial microstructure (including interfacial migration, phase composition and thickness of diffusion layers) have been examined systematically. We found that (1) The shift distance of Kirkendall marker and the inter-diffusion coefficient in solid Cu/solid Ni diffusion couples increased with increasing magnetic flux density in case of the direction of diffusion parallel to B; (2) The migration of the Bi/Bi_0.4Sb_0.6 interface due to the self-diffusion of the liquid metal into the solid alloy decreased markedly with the increase of magnetic flux density; (3) High magnetic fields exerted a non-monotonic influence on the thickness of diffusion layers during the reactive diffusion process between liquid Al and solid Cu; (4) The application of a high magnetic field during chemical reactive-diffusion process of gas Al/solid Cu system induced a significant change in the final products.

Abstract: In order to further study the mechanism of hydrolysis reactions to sugars using cornstalk on plasma, preliminary study of reactive process are carried out. Model compounds of cornstalk components are chosen and hydrolyzed on plasma. Activation energy of elementary reactions, which are single-molecule reactions, free radical reactions and bimolecular reactions, are calculated by bond energy percentage rules. Elementary reactions and preliminary reaction mechanism model, which cornstalk hydrolyzes to sugars on plasma are identified.

Abstract: Solute transport in porous media concerns advection, dispersion, sorption, and reaction. Since porous media is commonly heterogeneous, the properties of porous media are spatially and temporally variable. In this paper, one dimensional unsteady solute transport in semi-infinite heterogeneous porous media is investigated. Both linear and nonlinear decay is considered. Analytical solution is obtained for linear decay with spatially and temporally diffusion coefficient and velocity by using generalized integral transform technique. The inverse integral transforms are developed for the problems in semi-infinite space based on some weighted functions. Some examples are given to show the application of the method and analytical solutions.

Abstract: This paper deals with a class of hyperbolic thermo-plastic material equation. The equation includes a reaction-diffusion-taxis partial differential equation, a reaction-diffusion partial differential equation. In the actual course of the discussion, we append a motility term in the equation. Then, the existence of unique global strong solution is proved using the theory of fractional powers of analytic semi group generators to new equation.

Abstract: Processes involved in the structure and phase formation in the thin film systems Sn(4 nm)/Cu(14 nm) and Сu(14 nm)/Sn(8 nm) in the temperature range 130-500 оС were studied using “in situ” electron imaging and Transmission Electron Microscopy methods (TEM). Solubility of Sn α – solid solution Cu-Sn has been determined from the changes in the lattice parameter. This work was performed in the framework of the Swedish Institute supported cooperative research project “Thin metal films – the interplay of structure diffusion and boundaries” (SI dnr 00699/2009).

Abstract: Four kinds of the welding tools made of PCBN, W, WC and Al2O3 were applied to FSW of 304 stainless steel, and then the wear and reaction between the tool debris and the steel matrix were examined for each tool material. Severe tool damage was found in W, WC and Al2O3 tools after FSW, while the PCBN tool was hardly worn. Formations of Cr-rich borides, ferrite phases containing the high W contents and Cr-rich carbides were found in the stir zones produced using PCBN, W and WC tools, respectively. It was suggested that formation of those phases could be expected by calculation using the thermochemical database.

Abstract: Customer misbehavior tends to descend service delivery efficiency and social civilization and has become an important and difficult problem of service enterprises, with a small amount of researches and even less in China. The studies remain on the qualitative analysis and the quantity of researches on the consequence is the least. Therefore, based on the existing literature review, deep interviews and open questionnaires survey, this paper uses the widely accepted tool for the development of measurement methods, and develops a reliable and effective scale of customers’ reactions to other-customer misbehavior, which could be the measurement tool for further researches.