Transmission across boundaries

Mapping the transihons across boundaries between botanical parts in wheat and corn, shown as A-E on the wheat sechon (Figure 7.3a) and F-J on the corn kernel (Figure 7.3b), was accomplished in a raster scan procedure. This was achieved in a transmission mode between the hme that the IRps instrument was installed, and 1995. Spectra from each mapping experiment yielded functional group images... 

It has been proposed by others that this B segregation produces disorder at grain boundaries, thus facilitating slip transmission across them. This view is supported by a Hall-Petch type analysis of flow stress data as a function of the grain size. There are observations on disordered grain boundary layers which indicate the formation of the y-Ni-Al phase at the grain boundaries. This is not improbable since the A1 content of Al-deficient NijAl is near the solubility limit, and in the case of the LI 2 phase CU3 Au it has been found (Tichelaar et al., 1992) that the order-disorder transition is preceded by the formation of disordered layers at the interfaces. However, such disordered layers have also been found in NijAI without B, and have not been found in many ductile NijAl alloys with B (see also Lin et al., 1993 Sun and Lin, 1993). 

Another possible mechanism that has been proposed to explain why boron improves ductility is that it enhances slip transmission across grain boundaries. The... 

There were many examples of early interconnected electric transmission systems extending across state territories and beyond state boundaries. Statements from a speech by Samuel Insull at Purdue University in 1924 indicated that Minneapolis, St. Paul, St. Louis, Louisville, and Cincinnati soon would be interconnected and that extension of these systems to Pittsburgh and across the Allegheny Mountains to the Atlantic Seaboard could be easily conceivable in a few years. This was but one example across the United States. To quote Insull, It makes electric service available in new places for new pui poses, so that aggregate demand for service is spread over more hours of day and night, and thus opens the way to utmost economy in production and distribution. ... 

Eq. (5.5.4)]. Here, in addition to the condition K O, I, and 1, we also need 1 to obtain y l. This means that even when the ligand does induce conformational changes when binding to site a h 1) and to site b 1), the emergence of indirect correlation between a and b depends on the transmission of information across the boimdaiy between the two subunits a and b. When r = 1, there is no transmission of information across this boundary. (As we have seen in Section 4.7, = 1 is equivalent to the independence of subunits a and A.) When... 

Transmission electron microscopy has been used to determine the concentration of organic sulfur in coal. Because the electron beam can be focused to a fine spot on the coal specimen, the variation of organic sulfur in the macerals can be measured over distances as short as 1 pm or less. Thus, spatial variation can be determined within a particular maceral and across maceral boundaries in thinned coal foils. The excellent spatial resolution has also permitted us to measure the organic sulfur concentration in close proximity to sulfides we find that the organic sulfur concentration is constant over the maceral to within 1 pm of the pyrite. 

All process involves some sort of transmission among subsystems within a system, or among systems. There are inputs across the boundary into a system, internal processes within it, and outputs from it. Each of these sorts of transmissions may consist of either (a) some particular form of matter (b) energy, in the form of light, radiant energy, heat, or chemical energy or (c) some particular pattern of information. 

The process of twinning gives a crystal in which the atom positions are reflected across the twin plane (Figure 10.12c). Twins also tend to occur in bands (Figure 10.12d). The distinction between slip and twinning is best determined by means of X-ray crystallography or transmission electron microscopy, as these techniques are able to reveal the crystallographic relations on each side of a planar boundary. 

When two mismatched interfaces must be considered in the same plane, the net transmission coefficients is the product of the transmission coefficient across the two boundaries, i.e. ... 

A case of finite diffusion length with transmissive boundary conditions has also been considered in the literature [277, 278]. It corresponds to the case where hydrogen diffuses across a membrane and is oxidized on the other side. The same Eq. (7.74) is obtained but with tanh replacing coth in Eq. (7.75). 

Figure 11.47 Scanning transmission electron microscope measurements of the solute distribution across grain boundaries in Ti02 doped simultaneously with varying concentrations of Al and Nb. (B) represents a sample very close to the isoelectric point. (From Ref. 78a,b.)...

Also, the optical state (transmission, color) is very often practically the same on both sides of a zigzag wall, as in Fig. 93b. Indeed, if the director lies parallel to the surface (pretilt o =0) at the outer boundaries, the chevron looks exactly the same whether the layers fold to the right or to the left. However, if the boundary condition demands a certain pretilt a 5 0, as in Fig. 105, the two chevron structures are no longer identical. The director distribution across the cell now depends on whether the director at the boundary tilts in the same direction relative to the surface as does the cone axis, or whether the tilt is in the opposite direction. In the first case we say that the chevron has a C1 structure, in the second a C2 structure (see also Fig. 106). We may say that the Cl structure is natural in the sense that if the rubbing direction (r) is the same at both surfaces, so that the pretilt a is symmetrically inwards, the smectic layer has a natural tendency (already in the SmA phase) to fold accordingly. However, if less evident at first sight, the C2 structure is certainly possible, as demonstrated in Figs. 105 and 106. 

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