Heterogeneous regions, structure

Under certain time and temperature conditions, the homogeneous glass separates into two phases. One of the phases consists substantially of silicon dioxide which is insoluble in mineral acid. The other phase represents a soluble coherent boric acid phase rich in alkali borate. If the boric acid phase is dissolved out of this heterogeneous glass structure with a mineral acid, a porous skeleton of substantially insoluble silicon dioxide is left. The phase separation region occurs between 500°C and 800 C. 

We now deal with the structures that molecules build on substrate surfaces at full coverage, that is in the ML regime. Such hybrid systems are known as heterostructures. H. Kroemer dehned heterostructures as heterogeneous semiconductor structures built from two or more different semiconductors, in such a way that the transition region or interface between the different materials plays an essential role in any device action (Kroemer, 2001). The term heterostructure can be generalized to any... 

The efficiency of the initiation effect of triplet oxygen depends on the hydrocarbon structure, i.e., on the strength of the attacked C —H bond. For instance, the ratio of the rate constants of the reaction of oxygen with formaldehyde and methane is 1.3 x 109 at 100 °C [8]. This indicates that intermediates of oxidation may be more sensitive towards oxidation than the original substrate which may contribute to the appearance of heterogeneous regions where the oxidation takes place preferably. 

Whether axially or radially, gas-solid flow is heterogeneous in structure. Axial voidage profile characterizes a dilute region at the top and a dense region at the bottom, i.e., an S-shaped distribution curve. 

Other research confirmed the influence of the modification of bentonite in their adsorptive properties. The adsorption isotherms were determined with solutions of phenol in concentrations 50 mg L-i to 1000 mg L L in pH 6.5, at 20°C and 24 h. Structural changes were carried out with tetra-decy 1-trimethyl-ammonium bromide (TDTAB) and hexa-decyl-trimethy 1-ammonium bromide (HDTAB), with changes in 25%, 50% and 100% of capacity exchange cation. The equilibrium time was approximately 7 h and kinetic results indicated the possible presence of heterogeneous regions on the surfaces of clays modified with 25% and 50% of its cation exchange capacity. The clays modified with TDTAB and HDTAB in 100% obtained the best results for the removal efficiencies (Yilmaz Yapar, 2004). 

These decouplings of the transport coefficients, observed as a SE violation, have been attributed to the occurrence of dynamic heterogeneities in structural glass formers [99,100]. Thus, in supercooled liquids there exist regions of varying dynamics, that is, fluctuations that dominate their transport properties near the GT. 

As far as miscibility studies are concerned, no example of complete miscibility between the cubic phases of substances with different chemical structures could be observed. The binary mixture of compounds 2a-l and la-2 [8] shows a very restricted miscibility in the cubic phase (smaller than 5 mol% of the second component). The cubic phase of the polycatenar substance 7e-2 is able to incorporate about 80% of the rodlike component la-4 [20]. In the binary systems ll/la-4 [21], 10-3/la-4, 10-3/ 2a-3, and 10-3/11 [22] the cubic phases are separated only by a small heterogeneous region. 

That the anisotropic medium is localized beneath the receiver As seen in the previous point, in general, the anisotropy parameters are representative of the last anisotropic medium that the wave travelled through. Therefore, the assumption that the medium is local to the station is usually justified. However, in regions with heterogeneous anisotropic structure, data at a single station will not be consistent and the assumption will not be appropriate. 

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