Glass appearance

An expanded discussion of spin glasses appears in section 7.1.7... 

Carmine Lithium compounds (masked by barium or sodium), are invisible when viewed through green glass, appear violet through cobalt glass. 

Chromium(m) in lithium phosphate glass appears to be octahedrally co-ordinated and the value of peff (3.2 BM) suggests that some exchange interaction between the metal centres occurs in this medium.147 Polymeric complexes of chromium(m)... 

The third relaxation process is located in the low-frequency region and the temperature interval 50°C to 100°C. The amplitude of this process essentially decreases when the frequency increases, and the maximum of the dielectric permittivity versus temperature has almost no temperature dependence (Fig 15). Finally, the low-frequency ac-conductivity ct demonstrates an S-shape dependency with increasing temperature (Fig. 16), which is typical of percolation [2,143,154]. Note in this regard that at the lowest-frequency limit of the covered frequency band the ac-conductivity can be associated with dc-conductivity cio usually measured at a fixed frequency by traditional conductometry. The dielectric relaxation process here is due to percolation of the apparent dipole moment excitation within the developed fractal structure of the connected pores [153,154,156]. This excitation is associated with the selfdiffusion of the charge carriers in the porous net. Note that as distinct from dynamic percolation in ionic microemulsions, the percolation in porous glasses appears via the transport of the excitation through the geometrical static fractal structure of the porous medium. 

For particle sizes in excess of 20 nm, side illumination produces the Tyndall effect. Particles about 200 nm in size cause opalescence in transmitted light the glass appears yellow, in reflected light bluish (so-called opalines). Opal glasses show a milky... 

Pure water crystallized to snow appears white, for the transparence of the separate parts makes no tansparent whole. Various crystallized salts, when deprived to a certain extent of moisture, appear as a white powder. The accidentally opaque state of a pure transparent substance might be called white thus pounded glass appears as a white powder. The cessation of a combining power, and the exhibition of the atomic quality of the substance might at the same time be taken into the account. 

FIGURE 28-1. Chest x-ray demonstrating surfactant-deficient respiratory distress syndrome with ground glass appearance and air bronchograms. 

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