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Process surfaces

This section describes solid-gas surface processes on the surface monolayer adsorption, desorption, catalytic reaction, and surface diffusion. Non-ideal behavior of the systems is considered through the pair potentials of intermolecular interactions. A wide circle of experimental data can be [Pg.391]


The application of eddy currents in non destructive testing was very developed during the recent years. Adding to the defects characterization, actual studies deal with the metallurgical evaluation of materials. Surface processing allow to increase the material endurance and consequently its life duration. [Pg.290]

We showed that the impedance variation of low frequency probes is influenced by the coating depth. Consequently, the tempering increase and the surface processing decrease the permeability and the electrical conductivity. [Pg.296]

What structural changes accompany surface processes ... [Pg.685]

The plan of this chapter is as follows. We discuss chemisorption as a distinct topic, first from the molecular and then from the phenomenological points of view. Heterogeneous catalysis is then taken up, but now first from the phenomenological (and technologically important) viewpoint and then in terms of current knowledge about surface structures at the molecular level. Section XVIII-9F takes note of the current interest in photodriven surface processes. [Pg.686]

The sequence of events in a surface-catalyzed reaction comprises (1) diffusion of reactants to the surface (usually considered to be fast) (2) adsorption of the reactants on the surface (slow if activated) (3) surface diffusion of reactants to active sites (if the adsorption is mobile) (4) reaction of the adsorbed species (often rate-determining) (5) desorption of the reaction products (often slow) and (6) diffusion of the products away from the surface. Processes 1 and 6 may be rate-determining where one is dealing with a porous catalyst [197]. The situation is illustrated in Fig. XVIII-22 (see also Ref. 198 notice in the figure the variety of processes that may be present). [Pg.720]

Studies of surfaces and surface properties can be traced to the early 1800s [1]. Processes that involved surfaces and surface chemistry, such as heterogeneous catalysis and Daguerre photography, were first discovered at that time. Since then, there has been a continual interest in catalysis, corrosion and other chemical reactions that involve surfaces. The modem era of surface science began in the late 1950s, when instmmentation that could be used to investigate surface processes on the molecular level started to become available. [Pg.283]

The SHG and SFG teclmiques are also suitable for studying dynamical processes occurring on slower time scales. Indeed, many valuable studies of adsorption, desorption, difhision and other surface processes have been perfomied on time scales of milliseconds to seconds. [Pg.1296]

One interesting new field in the area of optical spectroscopy is near-field scaiming optical microscopy, a teclmique that allows for the imaging of surfaces down to sub-micron resolution and for the detection and characterization of single molecules [, M]- Wlien applied to the study of surfaces, this approach is capable of identifying individual adsorbates, as in the case of oxazine molecules dispersed on a polymer film, illustrated in figure Bl.22,11 [82], Absorption and emission spectra of individual molecules can be obtamed with this teclmique as well, and time-dependent measurements can be used to follow the dynamics of surface processes. [Pg.1794]

It is difficult to observe tliese surface processes directly in CVD and MOCVD apparatus because tliey operate at pressures incompatible witli most teclmiques for surface analysis. Consequently, most fundamental studies have selected one or more of tliese steps for examination by molecular beam scattering, or in simplified model reactors from which samples can be transferred into UHV surface spectrometers witliout air exposure. Reference [4] describes many such studies. Additional tliemes and examples, illustrating botli progress achieved and remaining questions, are presented in section C2.18.4. [Pg.2929]

Zalm P C, Kolfschoten A W, Sanders F H M and Vischer P 1987 Surface processes in ion-induced etching Nud. Instrum. Methods B 18 625-8... [Pg.2941]

Other Interaction Processes. The selectivity of flotation reagents in a pulp and their functions depend on their interactions with the mineral phases to be separated, but other physicochemical and hydrodynamic processes also play roles. AH adsorption—desorption phenomena occur at the sohd—hquid interfacial region. Surface processes that influence such adsorptions include activation and depression. Activators and depressants are auxiUary reagents. [Pg.49]

Paint-base phosphate coatings could be appHed in two to five minutes. In 1934, this time constraint was shortened even further when phosphate solutions were sprayed onto the metal surface. Processing times as short as 60 seconds became possible. [Pg.222]

Grinder Variables. The quaUty of pulp depends on wood species, moisture content, and grinder variables such as peripheral stone speed, grit size and number per unit area, and pattern on the stone surface. Process variables that affect pulp quaUty include grinding pressure pit consistency, ie, consistency in the space immediately below the grinder (2—6%) and temperature (40—80°C). The combination of moisture and raised temperature tends to soften the lignin. [Pg.259]

Under natural conditions the rates of dissolution of most minerals are too slow to depend on mass transfer of the reactants or products in the aqueous phase. This restricts the case to one either of weathering reactions where the rate-controlling mechanism is the mass transfer of reactants and products in the soHd phase, or of reactions controlled by a surface process and the related detachment process of reactants. [Pg.214]

Electroplating, Chromizing, and Other Chromium-Surfacing Processes... [Pg.119]

However, away from the surface, processes frequently are adiabatic. For example, if a volume (parcel) of air is forced upward over a ridge, the upward-moving air will encounter decreased atmospheric pressure and will expand and cool. If the air is not saturated with water vapor, the process is called dry adiabatic. Since no heat is added or subtracted. Ah in Eq. (17-13) can be set equal to zero, and introducing the hydrostatic equation... [Pg.252]

Kinetics of surface processes when used in a time-resolved mode. [Pg.443]

Fig. 5.6. Cross-sectional view of a liquid cell for in-situ AFM measurements of surface processes. Fig. 5.6. Cross-sectional view of a liquid cell for in-situ AFM measurements of surface processes.
Free convection currents generated by air heating or cooling by surfaces (process equipment, external walls)... [Pg.433]

Sorption Adsorption (a surface process) or absorption (a volume process). [Pg.1477]

In this review we put less emphasis on the physics and chemistry of surface processes, for which we refer the reader to recent reviews of adsorption-desorption kinetics which are contained in two books [2,3] with chapters by the present authors where further references to earher work can be found. These articles also discuss relevant experimental techniques employed in the study of surface kinetics and appropriate methods of data analysis. Here we give details of how to set up models under basically two different kinetic conditions, namely (/) when the adsorbate remains in quasi-equihbrium during the relevant processes, in which case nonequilibrium thermodynamics provides the needed framework, and (n) when surface nonequilibrium effects become important and nonequilibrium statistical mechanics becomes the appropriate vehicle. For both approaches we will restrict ourselves to systems for which appropriate lattice gas models can be set up. Further associated theoretical reviews are by Lombardo and Bell [4] with emphasis on Monte Carlo simulations, by Brivio and Grimley [5] on dynamics, and by Persson [6] on the lattice gas model. [Pg.440]

The following two pictures (Figure 6.2-8a and b) were acquired at h-500 mV and at -I-450 mV vs. Cu/Cu and show that at h-450 mV vs. Cu/Cu monolayer high Cu clusters nucleate at the steps between different Au terraces. Thus, the pair of shoulders in the cyclic voltammogram is correlated with this surface process. [Pg.309]

If the left-hand side of Eq. (11) is zero, dP/dt must be positive and d2P/dt2 negative, i.e. the maximum desorption rate is attained earlier than the maximum pressure. This distorting effect increases with an increasing value of d2P/dt2 (which depends on the kinetics of the surface process and therefore among others also on the heating rate) and with the increasing ratio... [Pg.357]

The following assumptions are made (i) the activated complexes are in equilibrium with the reactants, (ii) the energy of a molecule is not altered when an activated complex is substituted for a nearest neighbour, and (iii) the products do not affect the course of reaction, except to define a boundary in surface processes. The various cases can be recognized from the magnitude of the pre-exponential term and calculated values [515] are summarized in Table 7. Low values of A indicate a tight surface complex whereas higher values are associated with a looser or mobile complex. [Pg.94]

There have been several reviews of literature reports of compensation behaviour [36,521,522]. The observations made are relevant in the present context since kinetic characteristics of surface processes may be applicable also to changes proceeding at a solid—solid interface (i.e., two surfaces). Some of the explanations proposed for compensation behaviour (discussed in greater detail, with citations, in ref. 36) are that... [Pg.96]


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1" sensitivity surface cleaning processes

Abiotic processes surface

Adsorption Processes and Surface Reactions

Adsorption process at the surface of laminar flowing liquid films

Adsorption processes, surface complexation

Adsorption processes, surface complexation mechanism

Applying Surface Modification Methods to Promote Adhesion with Coating Processes

Assembly process Surface-Mount technology

Atomic surface modification process

Biogeochemical Processes Surface Water to Sediments

Bonding processes surface treatments

Catalyst surface structures processed

Cell surface oligosaccharides glycosylation process

Characterization of surface processes during oxide CMP by in situ FTIR spectroscopy

Combined surface exchange/diffusion process

Corrosion of process surfaces

Decompositions rate-limited by a surface or desorption step comparable in some respects with heterogeneous catalytic processes

Deposition processes surface reaction control

Deposition, surface, dynamic processes

Design limitations surface preparation processes

Drilling Processes Surface speed

Dyeing process surface

ET via Molecular-Recognition Process on Protein Surface

Electrochemical processes surface concentration

Electrode surface processes

Electrode surfaces reactant diffusion process

Electron Transfer Processes at Surfaces

Elementary Processes of Gas-Surface Interaction

Film forming processing surface-oriented phase

Functional Surface Properties by Plasma-Based Processes

GEOCHEMICAL PROCESSES AT MINERAL SURFACES

Gas-Solid Surface Reaction Processes

Heterogeneous process reactor surface material

Heterogeneous surface processes

Imaging surface processes

Instrument for Automatic Surface Tracking and Data Processing

Interfacial Electron Transfer Processes at Modified Semiconductor Surfaces

Kinetics surface, plasma processes

Kinetics, of surface processes

Laser surface processing, definition

Laser-chemical processes at surfaces nanoscale patterning

Metal surface, fouling process

Microkinetics of Elementary Surface Processes

Mineral processing surface characterization

Mineral processing surface characterization techniques

Mineral surfaces processes

Monitoring of Surface Processes

Offset processing surfaces

Oscillatory reactions surface process

Oxidation, surface processes

Photoelectrochemical Surface Processing

Polyimide surface modification process

Polymer processing modified surface studies

Polymer processing surface property modification

Process exploitation, response-surface methods

Process flow, surface maching

Process parameters reactor surface temperature

Processes at the Target Surface

Processes for Thin-Film Deposition and Surface Modification

Processing aids surface tack

Rate determining processes surface adsorption

Rate-controlled processes, dependence surface structure

Reflow processes surface defects

Response Surface Methodology optimization process

Self-Organization of Phthalocyanines on Surfaces by Solution-Processable Techniques

Sensitization Processes at Semiconductor Surfaces Modified by Dye Monolayers

Significant processes at the surface

Silica surface processes, research

Silicon oxidation surface-controlled process

Skill 4.1d-Explain how factors such as temperature, pressure, and surface area affect the dissolving process

Solid electrolyte interphase surface-related process

Sorption processes surface diffusion

Surface Chemical Processes of Diamond-Film Growth in Plasma

Surface Modification by Plasma-Based Processes

Surface Processes Weathering

Surface Redox Processes

Surface Segregation versus Consumption Processes

Surface adsorption processes and spot shape

Surface catalytic process

Surface chemical process

Surface cleaning processes

Surface cleaning processes and coating effectiveness

Surface cleaning processes coating effectiveness

Surface cleaning processes deoxidation

Surface confined process

Surface deposition, dynamical processes

Surface diffusion process

Surface engineering process risk

Surface engineering processes

Surface engineering processes classification

Surface finish Suspension process

Surface microlayers, chemical processes

Surface modification nanocomposite processing

Surface modification process using plasma

Surface modifications oxidation process

Surface photocatalytic processes

Surface photocatalytic processes semiconductor particles

Surface preparation process

Surface processed

Surface processed

Surface processes in GaAs epitaxial growth

Surface processes, crystal growth

Surface processes, crystal growth solution

Surface processes, silica

Surface processing

Surface processing electrochemical

Surface rate processes

Surface rheology and adsorption dynamics in drainage processes of

Surface roughness process risk

Surface sol-gel process

Surface step process

Surface texture modification process

Surface treatment process

Surface waters removal processes

Surface-modification processe

Surface-mount technology process steps

Surface-resistance controlled processes

Surfaces atomic processes

Textile surface structuring processes

The Microkinetics of Several Coupled Elementary Surface Processes

Wall conditioning processes, surface

Wet-process surface modification

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