Solid state processing methods

The difficulty in proving the exact nature of prethermal reactions is that they occur too fast for standard solid-state chemical methods. One attractive idea was expressed by Harbottle 29), namely that, if a strong isotope effect is shown, very little subsequent chemical influence can have been felt and the observed species must have been formed by prethermal processes. The supposition here is that isotopic differences come only from differences in the nuclear deexcitation pattern (total energy, y-ray cascades, angular... 

The use of these methods for speciation in solid materials requires that two essential assumptions—electrochemical reversibility and diffusive control—apply. Under these circumstances, theoretical CVs for ion-insertion solids are essentially identical to those for speeies in solution [206]. Since solid-state processes involve coupled... 

Abstract Membrane proteins represent an important and challenging frontier in structural biology they mediate fundamental and medically important processes but are challenging targets for structure/ function studies. Magic angle spinning solid-state NMR methods for structure determination of proteins have developed rapidly in... 

The methods most commonly used for preparing catalysts are precipitation (Section A 2 1 3) and impregnation (Section A 2 2 1 1) In both of them, the catalyti cally active material is transferred from a liquid phase, usually an aqueous solution, to a solid By contrast, other catalysts are obtained from solid precursors Solid state reactions, namely solid-to-solid reactions in which both the starting material (the catalyst precursor) and the catalyst are solids, offer convenient methods to prepare several industrial catalysts, especially those con taming two or more metallic elements or their oxides The reason of the conspicuous efficiency of these methods to prepare phases containing two or several metallic elements is due to special features of solid-state reactions, compared to liquid-to-solid or gas-to-solid reactions This section briefly outlines these peculiarities and presents the most frequent types of solid-state processes used in preparing catalysts... 

Solid-state nuclear magnetic resonance (NMR) has been extensively used to assess structural properties, electronic parameters and diffusion behavior of the hydride phases of numerous metals and alloys using mostly transient NMR techniques or low-resolution spectroscopy [3]. The NMR relaxation times are extremely useful to assess various diffusion processes over very wide ranges of hydrogen mobility in crystalline and amorphous phases [3]. In addition, several borohydrides [4-6] and alanates [7-11] have also been characterized by these conventional solid-state NMR methods over the years where most attention was on rotation dynamics of the BHT, A1H4, and AlHe anions detection of order-disorder phase transitions or thermal decomposition. There has been little indication of fast long-range diffusion behavior in any complex hydride studied by NMR to date [4-11]. 

In this section 10.2, we review the various solid-state NMR methods used to investigate interpolymer interactions, molecular motion and the spatial structure of a polymer blend. An interaction between component polymers affects the chemical shifts and lineshapes (see Section 10.2.2.1) and the molecular motions of the component polymers (see Section 10.2.2.2). In Section 10.2.3.1, microheterogeneity from 2 to 50 nm is studied by measuring spin diffusion indirectly from its effects on H spin-lattice relaxation. The spin-diffusion processes can also be monitored by several methods based on the Goldman-Shen experiment [8] (see Section 10.2.3.2). Homonuclear and heteronuclear two-dimensional correlation experiments reveal how and to what extent component polymers interact with each other (see Section... 

In this paper we have measured the resistance dependence and oxygen content of Er Ba2Cu 0Q and Y.Ba Cu OQ - samples above room temperature under the conditions or a simulated sintering and annealing process. The results provide insight into the importance of specific sample preparation procedures. We will start with a detailed discussion of the two most common preparation procedures for copper oxide superconductors at this moment the solid state reaction method and the coprecipitation method. A discussion of the resistance and thermogravimetric analysis (TGA) data and how it correlates to the sample formation will follow. 

The LB technique may also be combined with solid-state chemistry methods to produce novel molecular architectures. For example, a network of conductive polypyrrole (molecular wires ) may be obtained in a fatty acid matrix [37, 38]. First, monolayers of the iron salt of a long-chain fatty acid (e.g., ferric pahnitate) are assembled on an appropriate substrate. The multilayer film is then exposed to saturated HCl vapor at room temperature for several minutes. During this process, a chemical reaction transforms the fatty acid salt into layers of ferric chloride separated by layers of fatty acid. In the third and final step, the film is exposed to pyrrole vapor and a reaction occurs between the pyrrole and the ferric chloride, producing polypyrrole distributed within the multilayer assembly. 

Solid-state C NMR techniques provide a powerful means by which to obtain information about the carbon structure of fossil fuel materials. Indeed, CP/MAS measurements have been applied to coals and oil shales almost from their inception around 1976. Solid-state NMR measurements are now made routinely in fossil Riel research, particularly in coal structure studies. For oil shales, solid-state NMR methods are particularly useful because the measurements can be made on raw shale, without the need to remove the mineral matter, which generally accounts for >85 wt% of the rock. However, because of the reduced emphasis in developing oil shale deposits commercially, applications of NMR in oil shale research are now not as common as in the past. Nevertheless, NMR measurements have provided valuable information about various aspects of oil shales. For example, the extent of aromatization of aliphatic carbon moieties during conversion can be obtained by combining solid- and liquid-state NMR measurements with mass balance data. Such information is difficult to obtain by other methods and provides insight into the chemical processes associated with fossil fuel conversion. 

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