SR-XRD

Pigments in stratigraphic section may be analysed by TXRF (elemental composition), x Raman spectroscopy (functional groups) or XRD (structural analysis). At variance to conventional XRD, SR-XRD allows acquisition of patterns on thin stratigraphic sections... 

For the case of Li/Mg = 8/3 , Nakamura et al. determined the phase of Li2.6MgN2Di 4 as a dehydrogenated state (in vacuum conditions, at 200 °C) by using synchrotron radiation (SR)-X-ray and neutron diffraction [109]. For Li/Mg = 6/3, 8/3, 12/3 systems, Aoki et al. performed PC-isotherm measurements only for the dehydrogenation at 250 °C and observed the complex imide Li2Mg(NH)2 as a dehydrogented state by SR-XRD [110]. Considering all these experimental results, the reaction steps of the Li-Mg-N-H system can be stated as below,... 

One of the most exciting methodologies that has recently been applied to fat polymorphism is synchrotron radiation XRD (SR-XRD). It has made it possible to perform real-time (in situ) observations of polymorphic transformations at rapid... 

Figure 16 shows SR-XRD patterns of SLS taken during a temperature variation from 50°C to 10°C, kept at 10°C for about 10 min, and heated rapidly to 50°C (65). 

Very recently, the phase behaviors of the other types of saturated mono-acid binary mixtures TAGs, LLL (trilauroyl-glycerol)/(trimyristoyl-glycerol), LLL/PPP, and LLL/SSS, were examined by a SAXSAVAXS simultaneous measurement of SR-XRD (86). 

As an example, the SR-XRD patterns of the LLL/PPP = 60/40 mixture taken during cooling and heating processes are shown in Figure 17. During cooling, it was clearly shown that the p form of LLL and the a form of PPP were crystallized. As for the LLL fraction, direct crystallization of Plll SAXS peak at 3.2 nm and WAXS peaks at 0.42 and 0.38 nm occurred without the crystallization of aLLL-Almost at the same time, appp with a SAXS peak at 4.6 nm and a WAXS peak at... 

In SLS, the polymorphic transformation from a to y proceeded quite fast, because thermal energy easily accelerated the transformation between the two forms having rather low melting points. Therefore, Synchrotron radiation X-ray diffraction (SR-XRD) was employed to monitor the transformation process, since... 

Huq et al. (2001) have tentatively identified goyazite in Punic cosmetic pigments using synchrotron radiation X-ray diffraction (SR-XRD) techniques. 

A long time passed between the first discovery of AE3(BN2)2 phases [17] (AE = Ca, Sr) and their structural characterizations [18, 19]. Two distinct phases are known to exist for both calcium and strontium nitridoborate, denoted as low-temperature y9-AE3(BN2)2 and high-temperature a-AE3(BN2)2 [20]. Their phase transitions have been studied by temperature-dependent XRD, thermo-... 

Non-noble metal molybdenum containing carbonyls were studied for ORR activity.189-191 Mox(CO) and Mo,Sr(C 0) were studied side by side.189 190 These high-nuclearity carbonyl compounds were prepared by sintering. It was found that the Mox(CO) was amorphous by XRD, however, as S was added, a polycrystalline/ amorphous combination was formed in the catalyst. While neither Mox(CO) or Mo SyCO), compounds were found to be very active for ORR, the addition of S to Mox(CO) appeared to nullify any activity towards ORR.189 190 MoxSeJ,(CO) was produced by both screen printing and sintering191 as well as chemical synthesis.192 The screen printed catalysts were more active than the sintered catalysts, but as the amount of Se increased, the ORR activity decreased.191 192... 

Figure 3. XRD patterns (CuK radiation ethylene glycol-solvated samples) for Sr-exchanged K-smectites that have been subjected to 100 WD cycles in water at 60°C. A low-angle shoulder that indicates a trace of R1 ordering is marked by a tick on the Black Jack pattern. Peaks labeled in nm.

Figure 4. XRD patterns (CuK radiation ethylene glycol-solvated samples) showing a range of lllite contents for K-Kinney smectite that has heen subjected to various treatments. A = 100 WD cycles in 0.5 N NaCl B = 40 WD cycles in 0.5 N NaCl C = 100 WD cycles in 0.5 N KOH, with 1 Sr exchange D = 100 WD cycles in 0.5 N CaCl2 E = 100 WD cycles in 0.5 N KC1, with 1 Sr-exchange F = 100 WD cycles in 0.5 N CaCl2, with 1 Sr-exchange G = clay left in suspension for a time equivalent to 100 WD cycles, with 1 Sr-exchange. Peaks labeled in nm.

One of the first studies of how these secondary phases form was performed by van Roosmalen and Cordfunke. These authors used SEM/EDS and XRD to study postannealed diffusion couples of LSM and YSZ as well as pressed and fired powder mixtures of LSM and YSZ. These experiments showed that reaction products in sufficient quantity to detect by XRD (1—3%) form at temperatures as low as 1170 °C. The two principle reaction products observed were La2Zr207 (LZ) and SrZrOs (SZ), with the relative amount of LZ and SZ depending on the La/Sr ratio in the LSM. Calcia- and baria-doped LaMnOs were found to be similarly reactive with YSZ, and reactivity of LSM with YSZ having 3% or 8% yttria was found to be similar. In the case of the diffusion couples, the layer of reaction products formed at the interface was found (using SEM) to be on the order of 1 /xm after 600 h at 1280 °C and 10—15 fim after 600 h at 1480 °C. By employing Pt diffusion markers... 

SEM, TGA, and XRD analysis of the ICI Ni-based catalysts showed that carbon tended to form in downstream sections of the reactor, after the O2 was consumed. There were apparently two types of carbon. The first type apparently formed within the catalyst pores, causing physical breakage of the particles. The second type corresponded to whisker carbon with Ni particles at the ends (discussed earlier)—a deactivation pattern similar to that observed in conventional methane SR (also Ni-based) catalysts. 

AEM, ELL, EM, HEED, IMMA, LEED, SEM, SUMS, SRS, STEM, TEH, XEM, XRD Adhesive chemistry... 

Abbreviations DEA, dielectric analysis >OC. degree of crystallinity DSC, di erential scanning calorimetry LM, local mobility (secondary relaxations) SR, structural relaxation 7g, determination of glass transition temperature TSDC. thermally stimulated depolarization current spectroscopy XRD, X-ray difTractometry. Source Adapted from Ref. 15. 

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