Depth profiles density

FIGURE 3.1 Density-depth profile for the top 1,000 km of the Earth s mantle showing the main mineral phases present in the different layers. (Depth density data from Montagner. Anderson, 1989.)... 

The densities of the different layers within the Earth can be also be inferred by combining information from P- and S-body waves with data from surface wave oscillation periods. This then permits a density-depth profile to be constructed for the Earth, the mantle section of which is shown in Fig. 3.1. These data have been progressively improved and refined into a reference model for the Earth showing the average depth-velocity-density structure of the Earth. These data were first presented as a Preliminary Reference Earth Model (PREM -Dziewonski Anderson, 1981), the mantle part of which was subsequently refined by Montagner and Anderson (1989). 

Thermal expansion of thin (130-5 nm) PHOST films coated on various substrates has been measured by using specular X-ray reflectivity [487]. Complementary use of neutron and X-ray reflectometry has allowed one to measure the spatial evolution of the reaction front in the fBOC resist with nanometer resolution [499]. Using a bilayer geometry with a lower layer consisting of PHOST protected with COO(CD3)3 and an upper layer consisting of PHOST containing PAG, compositional and density depth profiles were measured. 

Fig. 12. iPP4 Density depth profile for different solidification pressures from 0.1 to 40 MPa a. diaphragm 3.5 mm thick b. diaphragm 8 mm thick... 

The reason for these results is that the intensity of the leakage field and the RMS error used depend strongly on the parameter c and the crack width, and to a lesser extent on the depth profile of the crack. Also, the distribution of the density of the leakage field is measured over the centre of the crack and correspondingly changes more by varying of dj and dj rather than of d, dj, dj and d . 

Both the Monte Carlo and the molecular dynamics methods (see Section III-2B) have been used to obtain theoretical density-versus-depth profiles for a hypothetical liquid-vapor interface. Rice and co-workers (see Refs. 72 and 121) have found that density along the normal to the surface tends to be a... 

Finally, the fundamental unit of concentration obtained by RBS is in atoms/cm or concentration in the sample-versus-bachscattering energy loss. To convert the profile of a backscattering peak into a depth profile it is necessary to assume a density for the material being profiled. For single-element films, such as Si, Ti, and W, an elemental density can be assumed for the film and an accurate thickness is obtained. In the case of multi-elemental films with an unknown density, a density for the film is calculated by summing the density of each element, normalized to its concentration. The accuracy of this assumption is usually within 25%, but for some cases the actual density of the film may vary by as much as 50%— 100% from the assumed density. It is useful to note that ... 

Since the nuclear and electronic scattering cross sections for alpha particles are well known, the relative concentrations of the elements and their depth profiles can be easily obtained. The relative element concentrations are determined by the relative scattering intensities. The depth profile is obtained from the energy spread of the scattered particles, which lose energy before and after the nuclear collision, by inelastic scattering with electrons. The knowledge of the elements areal density and of the film thickness allows the determination of film density. 

The depth profiling technique used on samples with a barrier film before and after the addition of chloride to the buffering borate electrolyte showed no indication of either chloride penetration or significant reduction of the average oxide layer thickness.123 This, of course, does not rule out the possibility of the formation, by any of the mechanisms suggested above, of pinholes with radii much smaller than that of the ion-gun beam, through which the entire active dissolution could take place, or the possibility that the beam missed pits formed sporadically across the surface. If pinholes which are not visible were formed, the dissolution should proceed in them with extremely high true current densities. 

DEPTH PROFILE. The secondary electrons produced by ionization processes from an incident beam of high-energy electrons are randomly directed in space. Spatial "equilibrium" is achieved only after a minimum distance from the surface of a polymer in contact with a vacuum or gaseous environment (of much lower density). Consequently, the absorbed radiation dose increases to a maximum at a distance from the surface (2 mm for 1 MeV electrons) which depends on the energy of the electrons. The energy deposition then decreases towards zero at a limiting penetration depth. 

Equation (10.1) can be used to determine the doping density of a silicon substrate and its depth profile, even if the flat band potential is not known accurately. Diffusion doping, ion implantation or the growth of an epitaxial layer are common methods of producing doped regions in semiconductor substrates. The dopant concentration close to the surface can be measured by SRP or capacitance-... 

Radiation cross-linking of polyethylene requires considerably less overall energy and less space, and is faster, more efficient, and environmentally more acceptable. Chemically cross-linked PE contains chemicals, which are by-products of the curing system. These often have adverse effects on the dielectric properties and, in some cases, are simply not acceptable. The disadvantage of electron beam cross-linking is a more or less nonuniform dose distribution. This can happen particularly in thicker objects due to intrinsic dose-depth profiles of electron beams. Another problem can be a nonuniformity of rotation of cylindrical objects as they traverse a scanned electron beam. However, the mechanical properties often depend on the mean cross-link density. ... 

Uncertainty in the depth history of a sample is a primary source of uncertainty for the cosmogenic-nuclide paleoaltimeter. Because of the >2000-fold difference in rock density versus atmospheric density, a 0.5-m uncertainty in depth is equivalent to >l-km uncertainty in altitude. Uncertainty in the depth of a sample during exposure is particularly problematic in regions where loess deposits may episodically bury a surface. For example, Hancock et al. (1999) find cosmogenic evidence of an ephemeral 0.5-1.5 m silt cap on currently uncapped, 600-ka terraces in the Wind River basin, Wyoming. The duration of time required to deposit a sedimentary layer may also result in a complex exposure history that can only be deduced with depth profiles and multiple nuclides (Riihimaki et al. 2006). However, Dunai et al. (2005) suggest that some deposits in the hyperarid Atacama Desert, Chile, have remained at the same depth without erosion or deposition for >20 Ma. 

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