FAST phase content

Actually, the IR absorption features depend on the chemical short-range order of the lattice, and their appearance is only a necessary (not a sufficient) condition for the existence of the respective phases. There exist some more BN phases with either sp or sp short-range order which show essentially the same IR absorption as hBN and cBN, respectively. However, if used in combination with more direct methods such as electron diffraction, IR absorption is a fast and reliable method for determination of the phase content of BN thin films and has found widespread application. In Fig. 4 the IR absorption spectrum of a BN film is given as an example which shows a distinct absorption near 1050 cm and only weak absorption at about... 

Since the 1980s, with wide applications of the highly automated X-ray spectrometer, scientists have used X-ray spectrometry to perform quantitative analysis of phase. This analysis principle is based on the relationship between phase content and diffraction intensity, and the method is simple and fast. Its accuracy can also meet the requirements if its component is not too complex. There are more than 20 quantitative methods such as internal standards, external standards, nil standards, adiabatic methods and theoretical calculations etc. Generally speaking, the more mature internal standard method requires a lot of time to draw the standard curve, and the curve can only apply to one matter, so this method has certain restrictions in quantitative analysis. In 1974, F. H. Chung proposed a skeleton washing method , also called as if-value method, which greatly simplified the X-ray quantitative analysis method, and has been widely used in various research fields. 

The separation of the products is not easy, although not impossible. For the exploration of the respective systems and their phase contents, it is, however, often not necessary to obtain pure products because modem, fast X-ray crystallography is an easy means to analyze even multiproduct reactions. Afterward, when the respective compounds are known, care has to be taken to produce the new compounds as pure phase by whatever route is desirable. One major advantage of the metallothermic reduction route is the fairly low reaction temperatures as these allow for the synthesis and crystal growth of compounds that decompose in the solid state, melt incongmently, or even form and decompose in the solid state at fairly low temperatures. Also, low-temperature modifications may be grown as single crystals below the transition temperature. 

The density of the ceramics obtained by FAST sintering is presented in Figure 8.3, compared with those obtained by conventional sintering. The phase content of the samples is presented in Table 8.1. It is noted that density close to the theoretical and almost full conversion to Al2TiOs (up to 92.5%) were achieved using FAST at 1050-1250 °C for 10 min. In the conventional sintering, formation of Al2TiOs occurs above 1300 °C and the density of the sintered samples represents about 70% of the theoretical one. 

In the first premix ME study (Suzuki et al., 1996) a cross-flow system was used in which coarse emulsion was diluted by permeation into a pure continuous phase/diluted emulsion recirculating at the low-pressure side of the membrane. In the majority of subsequent investigations (Table 6.2), a dead-end system was used, in which a fine emulsion was withdrawn as a product after passing through the membrane, without any recirculation and/or dilution with the continuous phase. It enables fast preparation of emulsions with a dispersed phase content of 50vol% or more (Vladisavljevic et al., 2004b). 

The dDAVP preparations used in this study were prepared in low water contents so that the lamellar phase was formed, which in turn was injected into the rabbits. The reason for this was the fact that the lamellar phase with its mucous-like rheology is easier to inject than the stiff cubic phase. Since the lamellar phase swells into the cubic phase in excess water according to the phase diagram in Figure 1, a phase transition was expected also in the in vivo situation. The transition was found to be very fast as judged by inspection of the injection site immediately after administration. 

Intestinal mechanical clearance thus consists of both reflex-mediated contractions (peristalsis) elicited by the stimulatory effect of luminal contents and of periods of spontaneous contractile activity (e.g. the migrating motor complex). During fasting about 50% of intestinal transit has been attributed to phase III of the migrating motor complex, the remaining mostly to the propulsive contractions and motor patterns during phase II [ 108]. Luminal flow can also occur in the absence of propagating contractions of the circular muscle layer, so far considered the motor event mainly responsible for flow in the small intestine. 

Local composition is very useful supplementary information that can be obtained in many of the transmission electron microscopes (TEM). The two main methods to measure local composition are electron energy loss spectrometry (EELS), which is a topic of a separate paper in this volume (Mayer 2004) and x-ray emission spectrometry, which is named EDS or EDX after the energy dispersive spectrometer, because this type of x-ray detection became ubiquitous in the TEM. Present paper introduces this latter method, which measures the X-rays produced by the fast electrons of the TEM, bombarding the sample, to determine the local composition. As an independent topic, information content and usage of the popular X-ray powder dififaction database is also introduced here. Combination of information from these two sources results in an efficient phase identification. Identification of known phases is contrasted to solving unknown stmctures, the latter being the topic of the largest fiaction of this school. 

It was assumed that there were no limitations on the rates of oxidation due to mass transport as discussed in detail by Schwartz and Freiberg (1981), this assumption is justified except for very large droplets (> 10 yarn) and high pollutant concentrations (e.g., 03 at 0.5 ppm) where the aqueous-phase reactions are very fast. It was also assumed that the aqueous phase present in the atmosphere was a cloud with a liquid water content (V) of 1 g m-3 of air. As seen earlier, the latter factor is important in the aqueous-phase rates of conversion of S(IV) thus the actual concentrations of iron, manganese, and so on in the liquid phase and hence the kinetics of the reactions depend on the liquid water content. 

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