Diffraction spectra

For instance, in the three crystalline forms (a, 3, y) of i-PP the chains are always in the conformation of threefold helix (s(3/l)l symmetry) but are packed in different ways in monoclinic [24], hexagonal [25], and orthorhombic [26] unit cells, respectively. The X-ray diffraction spectra of unoriented samples in the crystalline forms a, P, y are reported in Fig. 6. 

Fig. 6 a-c. X-ray diffraction spectra (CuKa) of unoriented samples of a) a form b) y form c) p form containing only minor a form impurities [41]... 

Because 0-acyl chitins appear to be scarcely susceptible to lysozyme, the susceptibility of DBG to Upases has been studied to obtain insight into its biodegradability in vivo. The changes in infrared and X-ray diffraction spectra of the fibers support the slow degradation of DBG by Upases [125,126]. The chemical hydrolysis of DBG to chitin is the most recent way to produce regenerated chitin. 

Figure 3. X-Ray diffraction spectra of the natural aurichalcite mineral (a), mineral aurichalcite calcined at 350°C for 4 hours (b), and the sample in (b) recalcined at 400 C for 4 hours (c).

Figure 1. Comparison of H2 generation from platinized hexagonal CdS (curve A) and cubic CdS (curve B) In Naflon 117. The Insert shows x-ray powder diffraction spectra of CdS In these films.

Samples with different loadings of rare earth and yttrium oxides on MS25 Si-Al were prepared and characterized. Figure 1 shows the x-ray diffraction spectra of a sample of 25% Nd203/Si-Al compared with the unmodified Si-Al. 

The chemical analyses of the samples are reported in Table 2. The X-ray diffraction spectra of these solids do not show the presence of any Cu oxide phase with size larger than 3-4 nm, excepted in the cases of Cu(3)Si02 and Cu(4)Zr02 on one side, Cu(146)Na(6)FAU-10 and Cu(146)Na(28)MFI-15 on the other side, where the lines characteristic of CuO do appear with a line broadening corresponding to a particle size of about 4 nm. 

Powder XR diffraction spectra confirm that all materials are single phase solid solutions with a cubic fluorite structure. Even when 10 mol% of the cations is substituted with dopant the original structure is retained. We used Kim s formula (28) and the corresponding ion radii (29) to estimate the concentration of dopant in the cerium oxide lattice. The calculated lattice parameters show that less dopant is present in the bulk than expected. As no other phases are present in the spectrum, we expect dopant-enriched crystal surfaces, and possibly some interstitial dopant cations. However, this kind of surface enrichment cannot be determined by XR diffraction owing to the lower ordering at the surface. 

Fig. 7.11 Effect of different experimental conditions on X-Ray diffraction spectra [46]. (a) Without orifice, 4% Ca(OH)2 slurry, 5 1/min C02 flow rate, (b) 1 mm orifice, 4% Ca(OH)2, slurry 5 1/min C02 flow rate, (c) 2 mm orifice 4% Ca(OH)2 slurry 5 1/min C02flow rate, (d) 3 mm orifice 4% Ca(OH)2 slurry 5 1/min C02 flow rate, (e) 4 mm orifice 4% Ca(OH)2 slurry 7 1/min C02 flow rate, (f) 4 mm orifice 2% Ca(OH)2 slurry 5 1/min C02 flow rate, (g) 4 mm orifice 6% Ca(OH)2 slurry, 5 1/min C02 flow rate, (h) 4 mm orifice 4% Ca(OH)2 slurry, 3 C021/min flow rate, (i) 4 mm orifice, 4% Ca(OH)2 slurry, 5 C02 1/min flow rate...

Interpretation of measurements of methods X-ray fluorescence spectrometry (Janssen and van Espen [1986] Arnold et al. [1994]), X-ray diffraction spectra (Adler et al. [1993]), NMR spectra (HIPS, Wehrens et al. [1993a]), HPLC retention indices (RIPS, Wehrens [1994]), Karl Fischer titration (HELGA, Wunsch and Gansen [1989]). 

Adler B, Schtitze P, Will J (1993) Expert system for interpretation of X-ray diffraction spectra. Anal China Acta 271 287... 

Figure 6.12. X-ray powder diffraction spectra of a CuInS2 thin film on Mo, prepared using SSP 7.

Diffraction spectra of a-quartz, recorded by energy dispersive and angle dispersive detectors, contrasting the different resolutions. The energy dispersive spectrum was recorded in 5 minutes while the angle dispersive record required 54 minutes. 

Electron diffraction provides experimental diffraction spectra for comparison with computed spectra obtained from various intuitive geometrical models, but this technique alone is generally insufficient to locate the hydrogen atoms. A quantum approach, on the other hand, indicates the positions of the H atoms, which can then be introduced into the calculation of the theoretical spectra in order to complete the determination of the geometry. 

Table 5 Changes in the crystallite size of some polycyclic pigments in coatings or plastics coloration as a result of heat exposure (calculated from the X-ray diffraction spectra).

Linear trans-quinacridones exhibit multiple crystal modifications. This phenomenon is reflected in the different reflection angles which are observed in the X-ray diffraction spectra of the pigment powders. This effect may be exemplified by describing the polymorphous phases of unsubstituted quinacridone. 

The novel modifications were characterized by different X-ray diffraction spectra. So far, like the S-modification [20] they are of no commercial importance. 

Fig. 93 shows the reflection angles of the a-, (3-, and y-crystal modifications. The measurements were carried out on powder diagrams derived from X-ray diffraction spectra. 

A standard method for confirming coherence of the layers is the study of x-ray diffraction spectra. If the layers are coherent and there are enough of them to provide a relatively strong Bragg diffraction pattern, satelhtes due to superlattice (see Chapter 16) formation should appear on each side of the Bragg diffraction peak. Although detailed treatments can be found in the literature, we present below a simplified but rather useful formula for the determination of layer periodicity. 

Binary Compounds. The thermodynamics of the formation of HfCl2, of HfCl4, fused sodium and potassium chlorides have been described. The reduction of ZrXj (X = Cl, Br, or I) with metallic Zr or A1 in molten AICI3 has been studied at temperatures from 250 to 360 °C, depending on the halide. The electronic spectra of the initial reaction products were consistent with either a solvated Zr complex or an intervalence Zr "-Zr" species. Further reduction resulted in the precipitation of reduction products which were identified by analysis and i.r., electronic, and X-ray powder diffraction spectra. The stability of the trihalides with respect to disproportionation was observed to increase from chloride to iodide thus ZrC and ZrCl2,0.4AlCl3 were precipitated, whereas only Zrlj was formed. ... 

CrP has been synthesized by reaction of the elements at pressures of 15— 65 kbar. The crystal structure involves chromium atoms co-ordinated by six phosphorus atoms in a distorted octahedral arrangement with Cr—P = 232—239 pm. CrMAs (where M = Co or Ni) have been characterized by A"-ray diffraction spectra. ... 

Analytical. Infrared absorption and x-ray diffraction spectra are given in Ref 21... 

Fig. 8. X-ray diffraction spectra for MSW bottom ash treated 0.4 moles of PO4 /kg of ash. The four fractions were produced using the presence or absence of treatment and the use of the Dutch Total Availability leaching protocol (from Crannell et al. 2000).

Success in preparing single crystals from linear dextran, and in obtaining electron diffraction spectra, suggests that information on the favored conformations of dextran in the solid state will soon be available.127... 

Spectral data. (e.g. new bands in U.V.—visible spectra, shifts and new bands in TR and Raman spectra, diffraction spectra). 

Goes over (25%) to HMX on treatment with 98% nitric acid at 5°(Refs 3 4). X-ray diffraction spectra of SEX are given in Ref 2, UV absorption spectra in Refs 5 7 and analytical procedures in Ref 8... 

E.DeVries E.St.Clair GantzJACS 76,1009 (1954) CA 48,7995(1954) (Dissociation constants of l-methyl-l-amino-3-nitroguanidine) 3)L.A. Burkardt, AnaiChem 28,323(1956) CA 50,7540 (1956) (X-ray diffraction spectra of 1-amino-l-methyl-2-nitroguanidine) (This compd was apparently ptepd at the US NavQrd Test Sta,China Lake,... 

X-ray diffraction spectra of 5-amino-l-methyl-a-tetrazole axe discussed in Ref 6, its thermal isomerization in Ref 9, and its UV and IR absorption spectra In Ref 10... 

Natta, Porri, Carbonaro and Lugli (25) have prepared copolymers of 1,3-butadiene with 1,3-pentadiene in the whole range of compositions. The properties of the copolymers, in which all butadiene and pentadiene comonomer units are in the trans-1,4 configuration, clearly show the isomorphous replacement between the two types of units. The melting point/composition data show that the copolymer melting temperatures are a regular function of composition and are always comprised between those of trans-1,4-polybutadiene modification II and trans-1,4-polypentadiene. Also the X-ray diffraction spectra of the copolymers show that the trans-1,4-pentadiene units are isomorphous with the trans-1,4-butadiene units crystallized in the crystalline modification of the latter stable at high temperatures (form II). 

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