Slabs, ablating

CsFeo.72Agi.28Te2,1053 and Cs2Ag2ZrTe4. The latter has a structure that comprises 2D slabs of Ag- and Zr-centered tetrahedral separated by Cs+ cations.1054 Gas-phase silver chalcogenide ions of the type [Ag2 i E ] (E = S, Se, Te) with < 14 have been investigated by laser-ablation Fourier transform ion cyclotron resonance mass spectrometry.1055... 

The method is later extended to time-varying heat inputs on one face with arbitrary boundary conditions on the back face (C7). Citron also has given a simple method of successive approximations for the finite ablating slab (C6) which is shown to converge rapidly for constant heat input. 

A closely related method is that of Boley (B8), who was concerned with aerodynamic ablation of a one-dimensional solid slab. The domain is extended to some fixed boundary, such as X(0), to which an unknown temperature is applied such that the conditions at the moving boundary are satisfied. This leads to two functional equations for the unknown boundary position and the fictitious boundary temperature, and would, therefore, appear to be more complicated for iterative solution than the Kolodner method. Boley considers two problems, the first of which is the ablation of a slab of finite thickness subjected on both faces to mixed boundary conditions (Newton s law of cooling). The one-dimensional heat equation is once again... 

Other passive network solutions are given by Hlinka and Paschkis (H8). Otis (01) employs the Landau transformation for the problem of an ablating slab with uniform initial temperature and specified heat fluxes at the front and back faces,... 

Lotkin (L10) gives a scheme for numerical integration of the heat conduction equation in a finite ablating slab, using unequal subdivisions in both space and time variables. Near the melting surface it is advantageous to choose rather small integration steps. Stability characteristics of the method are established. 

A few quick observations are in order at this point. The conducted energy is clearly reduced for large values of the heat of ablation. Similarly, the rate of material removal pVa is dependent on the heat of ablation and decreases for increased values of Hab. In order for this very simplified solution to apply, the overall slab thickness 8 must be large compared with the depth of penetration of melting. In terms of the above parameters this means that... 

For the spherical model, it was necessary to calculate the radius of an initially hemispherical polymer mass, Rs, based on the volume of the ablated slab, V=A<5, as a starting point for the numerical integration of Eq. 5. These radii are given in Table 4. 

However, in cases where spatial information is crucial, zircons (or other minerals) can also be analyzed in polished slab or thin sections of rock [21]. Separated zircons are mounted in epoxy and polished to expose the parts that will be targeted for dating. The targets for LA-ICP-MS analysis are generally selected based on cathodoluminescence imaging [22] (Figure 9.3). Prior to ablation, the sample is generally cleaned with nitric acid to remove any surface contamination, most notably Pb. 

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