Glass anomalous

Most glasses have dispersions which follow a standard relation with change of wavelength. Some glasses have anomalous dispersion, and these are useful for the design of highly colour-corrcctcd lens sets, so-called apochromatic objectives. 

Because the concentration difference between MORB and hydrothermal chimney materials for both Ba and Ra is greater than lO , incorporation of small amounts of barite from hydrothermal systems could create the high ( Ra)/( °Th) observed in MORB. However, if Ra excess results from this process, then Ba concentrations (and Ba/Th) should be equally raised by such contamination. However, Ba/Th in highly depleted glasses from the Siquieros Transform that have ( Ra)/( °Th) greater than 3 are typical for MORB and do not have anomalously high Ba contents (Lundstrom et al. 1999). 

Criteria 1-3 are the cardinal characteristics of Fickian diffusion and disregard the functional form of D(ci). Violation of any of these is indicative of non-Fickian mechanisms. Criterion 4 can serve as a check if the D(ci) dependence is known. As mentioned, it is crucial that the sorption curve fully adhere to Fickian characteristics for a valid determination of D from the experimental data. At temperatures well above the glass transition temperature, 7 , Fickian behavior is normally observed. However, caution should be exercised when the experimental temperature is either below or slightly above 7 , where anomalous diffusion behavior often occurs. 

It is evident that if both techniques could be applied to one system, there is a much greater probability of assessing the over-all changes that take place on adsorption. Furthermore, the information obtained from each technique will supplement the other. An example of this is a study of the effects due to replacement of the surface OH groups. In earlier work with porous glass, the anomalous curves, and the contractions at low coverage. 

Vitreous Silica Vitreous sdica is a glass form of sdica composed of Si02. It may be transparent, translucent, or opaque. It has a number of abnormal and anomalous properties in thermal expansion, viscosity, bulk density, compressibility, and elasticity. These properties depend on thermal history and preparation method. Vitreous sdica exhibits high resistance to chemical attack. At ambient temperature, it is not attacked by any chemical except hydrofluoric acid. 

The classic example of a NEAS is a supercooled liquid cooled below its glass transition temperature. The liquid solidifies into an amorphous, slowly relaxing state characterized by huge relaxational times and anomalous low frequency response. Other systems are colloids that can be prepared in a NEAS by the sudden reduction/increase of the volume fraction of the colloidal particles or by putting the system under a strain/stress. 

Kazansky PG, Inouye H, Mitsuyu T, Miura K, Qiu J, Hirao K, Starrost F (1999) Anomalous anisotropic light scattering in Ge-doped silica glass. Phys Rev Lett 82 2199-2201... 

According to F. P. le Roux, like all vapours with a large selective absorption, iodine has an anomalous dispersion since it increases with a fall of temp., being about 0 06 from A. Hurion s measurements—approximately as large a negative number as glass is positive. The atomic refraction of solid iodine is 24-5 by the //.-formula, and 14-12 by the /t2-formula. 

Anomalous effects are often observed due to solution entering the capillary at the instant the mercury drop falls. In ac measurements, this phenomenon leads to anomalous frequency dispersion [12], In addition, the drop time becomes irreproducible. These effects may be diminished to a large extent by coating the internal wall of the capillary with a film of silicone [13]. A tip made of hydro-phobic (solvophobic) material may also be attached to the glass capillary. For example, a polyethylene tip was used [14] to discriminate against the attack of fluorides on glass in the study of double-layer structure in the presence of fluorides. In another study, capillary tips were modified with commercial narrow-bore PTFE tubes to determine arsenic in basic solution [15]. This procedure is also used for the hanging mercury drop electrode discussed in Section III. 

As discussed by Kirkpatrick [10], this slow mode is important in the theories that include mode coupling effects. Such theories have been used to quantitatively understand the anomalous long-time tails of the stress-stress correlation function and the shear-dependent viscosity [3, 30, 34], observed in computer simulations. As mentioned earlier, a theory of glass transition has also been developed based on the softening of the heat mode. 

Tg data for the blends are shown in Figure 1. Results obtained by DTA on PMMA-PVdF blends which had been melt extruded and "annealed at room temperature appeared to be anomalous in terms of the theory for glass transition of copolymers or compatible polymer blends (6). These data indicated a limiting value for Tg of ca. 40°-45°C. However, x-ray examination showed that samples with more than ca, 35% PVdF exhibited a crystalline phase, indicating that some of the PVdF had precipitated. When these systems were re-examined by dilatometry... 

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