Deposition rate calculation

Close agreement was noted between deposition rates calculated by summing individual contributions from each transport mechanism and deposition rates calculated from a rigorous consideration of their combined effect. Thus the additivity rule was verified for the cases studied. 

The data suggest that both the initial deposition rate and the asymptotic deposit mass are both dependent upon the bulk velocity u raised to the power 0.6 - 0.7. The results were also compared with the mass transfer rates of Cleaver and Yates [1975] and Metzner and Friend [1958]. Although the dimensionless particle relaxation times (see Section 7.3) were below 0.1, the inertial deposition rates calculated from the theory of Cleaver and Yates were of an order of magnitude higher than the difiusional rates calculated and indeed measured. The measured power on velocity of 0.7 compared to a theoretical value of 0.875 for difrusion and 2 for inertial particle transfer, suggest a diffiision controlled mechanism. 

Physical Sputter Deposition Rate. Calculate the physical sputter deposition rate assuming a sputtering coefficient ysput = L an incident ion flux Fj = 10 cm s , and density of the deposited film f = 5 10 cm. Also assume that all sputtered material is deposited on the substrate, and the area of the sputtered target is equal to the substrate area where the film is deposited (At = Asub)-... 

It is important to note tlmt tlic deposition rate is a strong function of particle dimneter tluough the term v, wliich appears twice in tlic deposition flux equation. Equation (9.7.10) must be modified to treat process gas streams discliarging particles of a given size distribution. The suggested procedure is somewhat simihu to tlial for calculating overall collection efficiencies for particulate control equipment (12). For this condition, the overall rale is given by... 

Chemical vapor deposition processes are complex. Chemical thermodynamics, mass transfer, reaction kinetics and crystal growth all play important roles. Equilibrium thermodynamic analysis is the first step in understanding any CVD process. Thermodynamic calculations are useful in predicting limiting deposition rates and condensed phases in the systems which can deposit under the limiting equilibrium state. These calculations are made for CVD of titanium - - and tantalum diborides, but in dynamic CVD systems equilibrium is rarely achieved and kinetic factors often govern the deposition rate behavior. 

Fig. 5. Spatial distribution of net osmoticum deposition rate per mm root length in the apical 10 mm of maize primary roots growing at various vermiculite water contents (see Fig. 3). The data were computed from distributions of growth rate and osmotic potential (Fig. 4), as described by Silk et al. (1986). The inset shows the total osmoticum deposition rate in the apical 9 mm for the different treatments, calculated by integrating the rates over distance. Modified from Sharp et al. (1989).

Experiments of propane pyrolysis were carried out using a thin tubular CVD reactor as shown in Fig. 1 [4]. The inner diameter and heating length of the tube were 4.8 mm and 30 cm, respectively. Temperature was around 1000°C. Propane pressure was 0.1-6.7 kPa. Total pressure was 6.7 kPa. Helium was used as carrier gas. The product gas was analyzed by gas chromatography and the carbon deposition rate was calculated from the film thickness measured by electron microscopy. The effects of the residence time and the temperature... 

The discrepancy may also be caused by the approximations in the calculation of the EEDF. This EEDF is obtained by solving the two-term Boltzmann equation, assuming full relaxation during one RF period. When the RF frequency becomes comparable to the energy loss frequencies of the electrons, it is not correct to use the time-independent Boltzmann equation to calculate the EEDF [253]. The saturation of the growth rate in the model is not caused by the fact that the RF frequency approaches the momentum transfer frequency Ume [254]. That would lead to less effective power dissipation by the electrons at higher RF frequencies and thus to a smaller deposition rate at high frequencies than at lower frequencies. 

In the ASTER reactor deposition experiments were performed in order to compare with the 2D model results. Normalized deposition rates are plotted in Figure 22 as a function of radial position for data taken at 25 and 18 Pa. The deposition takes place on a square glass plate. For each pressure two profile measurements were performed, each profile perpendicular to the other (a and b in Fig. 22). A clear discrepancy is present. The use of the simplified deposition model is an explanation for this. Another recent 2D fluid model also shows discrepancies between the measured and calculated deposition rate [257], which are attributed to the relative simplicity of the deposition model. 

FIG. 66. Effects of modulating the RF excitation frequency (a) deposition rate and average light intensity as a function of the modulation frequency, with the deposition rate at cw conditions indicated by the dotted line, (b) measured spectrally integrated emission and calculated production of SiH3 radicals as a function of time, at a modulation frequency of 50 kHz and a 509f duty cycle. [From A. C. W. Biebericher. J, Bezemer. W. F. van der Weg, and W. J. Goedheer, Appl. Phys. Lett. 76, 2002 (2000), 2000, American Institute of Physics, w ith permission.]... 

FIG. IS. Calculated relative deposition rate as a function of N content in film, for several values of the interaction parameter a. (Reproduced from 74).l... 

The accuracy of the measurement of radon concentrations with bare track detectors was found to be unsatisfactory due mainly to the changes of the deposition rate of radon progeny onto the detector as a result of air turbulence. In this work, therefore, a method was developed which can correct the contributions of the deposition to the track densities by classifying the etched tracks according to their appearance, i.e. round or wedge shaped. Using this method, about 30% improvement in the error of measurements was achieved. The calibration coefficient ob tained by experiment was 0.00424 tracks/cm /h/(Bq/m ), which agreed well with the calculated value. Comparison was also made of the present method with other passive methods, charcoal and Terradex, as to their performance under the same atmosphere. 

Data on the rate of attachment or deposition, i.e., plate-out of radioactive particles on walls can be used to calculate the particle deposition velocity. Deposition rates can be determined experimentally by measuring the surface activity on some samples... 

The deposition rate of the attached fraction, plotted in Figure 3, is calculated from the aerosol size distribution assuming diffusion and electrophoresis to be the most important deposition mechanisms (Raes et al.,1985a). The accuracy of the absolute values was checked by forming the aerosol mass balance after the generation of a high aerosol concentration.In Table II is compared the decay of the... 

On this basis the ventilation rate was fitted to the data at high attachment rates and compared to the measured ventilation rate so that the ratio of the "outroom" to the "inroom" daughter concentration (P) could be calculated (Table III). Afterwards the deposition rate of the unattached daughters was calculated from the... 

Figure 5. Relative standard deviation on the fitting of the deposition rate of the unattached daughters (Xun) and on the fitting of the ventilation rate (Xvent)> calculated by means of a Monte- Carlo simulation model. The lower curve is obtained with counting statistics alone. The upper curve includes one hour time fluctuations on the input parameters, with 10% rel. stand, dev. on X, un (15/h), a(.35/h), Vent(.45/h) and radon cone. (50 bq/m ) and 2% on recoil factor (.83), penetration unattached (.78) and flow rate (28 1/min).

In Figure 9 it is shown that the attachment rate is the dominating factor for the unattached fraction. The equilibrium factor however, is also strongly influenced by the deposition rate of the unattached daughters. The curves are calculated as in Figure 7. The limited fluctuations of the actual data illustrate the importance of the attachment rate. 

The noble gas elements act as a record of the deposited material because they are essentially chemically inert and are also trapped within the ice of comets and meteorites. The late-heavy bombardment era must have affected both the Earth and the Moon similarly so an estimate of the collision frequency may be obtained by using the record of impacts on the Moon s surface. The collision rate calculated... 

The 210Pb inventory in the sediments was calculated in a similar way to the 239,240pu method described previously, but 1 cm increments were used in determining the integrated deposition. The deposition rate of the 210Pb for each core was determined as the product of the integrated deposition and the radioactive decay constant, (A. =. 0311 yr-1). Since the unsupported 210Pb (t ... 

The Comprehensive Acid Deposition Model (CADM) has been created for calculation of dry and wet deposition of sulfur species over South Korea (Park et al 1997,1999a). This model presents quantitative assessment of the acidity loading and alterations in deposition rates. 

In region I, polymerization may be initiated by ion bombardment and the deposition rate may be propotional to the number of ions (27). In this study, the discharge current was almost constant in the discharge frequency region from 50 Hz to 200 KHz. If the effective discharge current is I and the shape of discharge current wave is sinusoidal, the mean current which will flow to either electrode may be calculated by the following equation ... 

Airborne salinity can be determined using different methods. In corrosion research the standard method (Wet Candle method) is established in ISO-9225 1992 [33] however, it is not the only method traditionally used. In the case of Cuba it has been widely used the method named as dry plate method, consisting in the employment of a dry cotton fabric of known area exposed under a shed. The amount of chloride deposition on the gauze is determined analytically at the end of the exposure period (two months) and the deposition rate is calculated. 

Fig. 9. Calculated and experimental polymer deposition rates for olefins as a function of monomer flow rate [after Tibbitt et al. ]...

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