Sample holders diffraction patterns

Compression molded (150°C for 3 minutes press chilled with cold water immediately thereafter) samples of poly(trans-l,4-hexadiene) (14) and poly(5-methyl-l,4-hexadiene) were examined with a General Electric (XRD-3) X-ray unit. Transmission Laue X-ray photographs were taken using nickel filtered copper X-radiation. Samples were stretched to four times of their original lengths to obtain oriented fibers. The fiber patterns were obtained in a flat plate film holder with the specimen to film distance standardized at 5 centimeters. X-ray diffraction patterns were similarly obtained for the hydrogenated sample of poly(5-methyl-l,4-hexadiene). 

Figure 16.4. Diffraction patterns of (a) as deposited and (b) heat-treated thin electrolessly deposited Ni-P films (c) as deposited and (d) heat-treated electrolessly deposited Cu film. Films were heated and examined in the sample holder of an electron microscope.

X-ray powder diffraction was recorded using a conventional x-ray powder diffractometer with Cu-Ka radiation. Polyimide film on which sample particles are deposited is glued on a glass sample holder with vacuum grease. Figure 1.6.9 shows the recorded diffraction pattern. An analysis of the pattern is made by comparing the lattice parameters and diffraction intensities of the particles and those of known iron compounds, and shows that the particles are Fe304. 

The cuvette must be correctly placed in its holder so that the laser beam is perpendicularly incident upon it. If the cuvette is not fixed correctly the laser beam is deflected from its normal path, which leads to a nonuniform and incorrect diffraction pattern. Many commercial instruments have the ability to adjust the alignment of the laser beam once the cuvette has been correctly inserted into the sample holder, to ensure that it is perpendicularly incident. 

The X-ray powder diffraction (XRPD) pattern of a sample of atorvastatin calcium, Form-I, was recorded at room temperature on Bruker D8 Advance diffractometer (Karlsruhe, Germany), using nickel-filtered Cu Ka radiation. The sample was mounted in a polymethylmethacrylate sample holder, and analyzed in a continuous mode with a step size of 0.01° and a step time of 1 s over an angular range of 3-40° 26. The XRPD results are found in Fig. 1.18 and in Table 1.3, being evaluated with the DIFFRACplus EVA (version 9.0) diffraction software. 

The x-ray powder diffraction pattern of etodolac was obtained using a Rigaku MiniFlex powder diffraction system, equipped with a horizontal goniometer in the 0 /2-0 mode. The x-ray source was nickel-filtered K-a emission of copper (1.544056 A). A 10-mg sample was packed into an aluminum holder using a back-fill procedure, and was scanned over the range of 50 to 6 degrees 2-0, at a scan rate of 0.5 degrees 2-0/min. 

Diffraction patterns can be used to identify the various phases in a catalyst. An example is given in Fig. 10.3b, where XRD is used to follow the reduction of alumina-supported iron oxide at 675 K as a function of time. The initially present oc-Fe2C>3 (haematite) is partially reduced to metallic iron, with Fe3C>4 (magnetite) as the intermediate. The diffraction lines from platinum are due to the sample holder [10]. 

Investigations of the x-ray diffraction patterns of various low temperature (450°-750°C) synthetic carbons (18)t carbon black blended with polyethylene (15), condensed aromatics of known structure where the maximum diameter of the sheets is approximately 14 A (15) as well as mixtures of condensed aromatics and porphyrins (19) indicate that the x-ray diffraction patterns can be reproduced thereby supporting the concept of condensed aromatic sheets (having a tendency to stack) as the structure of asphaltenes. However, it is perhaps this ease with which the x-ray diffraction of the asphaltenes can be reproduced which dictates that caution is necessary in the interpretation of the data. Indeed, any empty polyethylene sample holder will exhibit a similar... 

For characterization of the catalyst candidates by X-ray diffraction, well-powdered samples were placed onto the sample holder of a DRON 3 diffractometer and the X-ray patterns were registered in the 3° < 2d < 45° range. 

Figure 7.12. The observed and calculated powder diffraction patterns of CeRhGcs after the completion of Rietveld refinement. The data were collected from a ground CeRhGcs powder dusted on a flat sample holder using a rotating anode Rigaku TTRAX powder diffractometer in a step scan mode with a step A20 = 0.01°, All notations on the plot are identical to Figure 7.2.

Figure 4.1 Diffraction patterns of usual sample holders (0.5° div. slit). For thin samples, or with a too wide divergence slit, these patterns may be superimposed on the sample pattern. For a plastie framed background free Si single crystal holder a plastic hump appears in the lower angle area (for 1° div. slit this starts already at 18 ), The sharp reflections in 2 originate from the inorganic filler (feldspar ). Normal white Perspex resembles the given plastic curve (4). A blue Perspex of unknown origin was found to be almost free of background (3).

The magnetic field is maintained for 2 h, and the sample is cooled rapidly on a cold metal surface or with liquid nitrogen as soon as the power supply of the magnet is turned off. The film is then placed in the sample holder of a suitable X-ray diffractometer (with axis vertically aligned) and the diffraction pattern is recorded with a flat-plate camera. 

Powder X-ray diffraction patterns were obtained with a SIEMENS D-5000 diffractometer using the Ka-radiation of a copper anode. The samples were analyzed after deposition on a quartz monocrystal sample-holder supplied by Siemens. The crystalline phases were identified by reference to the ASTM data files. 

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