Amorphous homogeneous solids

Mechanisms of Materials Transport ia Amorphous Homogeneous Solids... 

Mechanisms of Materials Transport in Amorphous Homogeneous Solids 63... 

Mixed crystal is a homogeneous crystal of two or more substances. Solid solution is a homogeneous solid mixture of substances. Both are virtually equal, although the latter can be amorphous. In general, mixed crystals are obtained from molecules of similar shapes and sizes. The forces between molecules are usually weak. Compositions can vary throughout a certain range and crystal structures are disordered,... 

Most of the solid components of the Earth s crust, i.e. rocks, sediments, clays etc. are largely made up of various mineral species. Amineral species is deiined as A naturally occurring, inorganic, homogeneous solid, having a definite (but not necessarily fixed) chemical composition and a fixed ordered internal structure, i.e. crystalline. This ordered internal structure is reflected in the external morphology when the mineral has a well crystalline form. When the crystalline form is not perceptible externally called cryptocrystalline, its crystalline nature can be detected by scientific analytical techniques like X-Ray Difiraction. Amorphous natural solids like coal, volcanic glasses etc. do not qualify as minerals. The abimdance of any mineral in the Earth is decided by the availability of the constituent elements of the mineral in the earth s crust and also the stability of that mineral in the surface or near-surface environment. 

The handling of MBP requires consideration of heat, moisture, and shear stress that may destabilize the MBP. In a study of solid dispersion of Compound Y, the MBP ASD prepared by MBP process provided a uniform and homogeneous solid solution of amorphous drug embedded in polymer while the same composition prepared by... 

Reactions in amorphous polymer solids are first characterized in terms of influences of molecular motion of matrix polymers and non-homogeneity of reaction sites. Specific features of photophysical processes, photoisomerization, photodimerization, chain scission and crosslinking reactions in polymer solids are then discussed separately. 

Ti or Si in complete homogeneous solid solution could be possible with the bulk-amorphous alloys. 

The reaction product mixture is a homogenous solution having a pH of about 6. It is evaporated under vacuum to a semisolid residue. To the residue are added 35 ml of water and a few drops of triethylamine to raise the pH to 8. The aqueous solution obtained thereby is extracted successively with 50 ml and 35 ml portions of ethyl acetate, the pH being adjusted to 2 at each extraction with hydrochloric acid. The extracts are combined, filtered, dried over sodium sulfate, stripped of solvent, and evaporated under vacuum. The product is 7-(N-carbobenzoxy-D-o -aminophenylacetamido)cephalosporanic acid in the form of a yellow-white amorphous solid weighing 1.10 g. 

The dynamic mechanical behavior indicates that the glass transition of the rubbery block is basically independent of the butadiene content. Moreover, the melting temperature of the semicrystalline HB block does not show any dependence on composition or architecture of the block copolymer. The above findings combined with the observation of the linear additivity of density and heat of fusion of the block copolymers as a function of composition support the fact that there is a good phase separation of the HI and HB amorphous phases in the solid state of these block copolymers. Future investigations will focus attention on characterizing the melt state of these systems to note if homogeneity exists above Tm. 

Palladium acetate, [PdO —02CCH3)2l3, possesses a unique quality that makes it attractive for solid state decomposition studies as well as technological applications. It can be spin-coated from solution to form a homogeneous, apparently amorphous solid film. This provides large uniform areas over which we can study the effects of various irradiation sources on the chemical nature of the film. The bulky structure of palladium acetate, shown in Figure 1 (8), may offer a partial explanation of the molecule s ability to achieve an amorphous metastable phase upon rapid evaporation of solvent. 

According to the principles of polycondensation, all of the above reactions will also take place during SSP. The conditions for the latter, however, are different as this process is carried out at lower temperatures in a non-homogeneous environment. In order to examine the kinetics of SSP, some assumptions have to be made to simplify the analysis. These are based on the idea that the reactive end groups and the catalyst are located in the amorphous regions. Polycondensations in the solid state are equilibrium reactions but are complicated by the two-phase character of the semicrystalline polymer. 

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