Powders sample preparation

Fig. 7.4 XRD signal for powder samples prepared from bulk Si (top) and micro PS films produced on p-type electrodes using different anodization current densities, as indicated in...

In 1974, the electrical conductivity of LajCuC was re-determined (130) on a powdered sample prepared at 900-950°C. A 4-probe d.c. cell was used and the electrical data obtained between 100 and 900°C indicated this material to be a metallic conductor. A slight anomaly in the conductivity was noted at 310°C. 

The mineralogical composition of all the samples included in the study was determined by XRD, using the same powdered sample prepared for XRF analysis. Measurements were performed using a PANalytical X Pert PRO alphal powder diffractometer (radius = 240 mm) using the Cu Ka radiation (A. = 1.5418 A), with a working power of 45 kV - 40 mA. The incident beam was passed through a 0.04 radians Soller slit, and the diffracted beam passed through a second slit. Moreover, the diffracted beam was Ni filtered. An X Celerator... 

In Table 8.1, cow s milk, breast milk, and infant formulae are considered together under the entry Milk and infant formulae, irrespective of the actual liquid or powdered form of the samples analyzed in each single study, because all these items share a similar matrix and pose analogous analytical problems. Triton X-100 has been used to measure Pb isotope ratios in milk powder samples prepared as slurries [39]. Simple dilution of fresh milk in alkaline media (in order to prevent protein precipitation) has also been successfully applied by other authors [40], especially for I determination [41-43], even though in most studies milk and infant formulae are analyzed following full digestion. 

Nitrogen-Concentration Dependence on Photocatalytic Activity of Ti2-xNx Powders. Samples prepared by annealing anatase Ti02 under NFL flow at 550-600 °C. 311... 

The M-NM transition has been studied in powder samples (prepared by the ceramic method) of the series of perovskite oxides Lai- TiOs with 0 temperature dependencies to the magnetic susceptibility (Fig. 7.6a) and electrical resistivity (Fig. 7.6b) for different compositions, as well as the cell parameters for the phases ... 

YbCdCu4 have been measured on powdered samples prepared from single crystals. variable-amplitude cross-polarization (VACP) and... 

Fig. 3. Examples for the differences between the line profiles of Gd NMR spectra of ferromagnetically ordered GdAlj. Zero-field spectra of an annealed powder sample (x) and of a powder sample prepared for optimum resolution of the quadrupolar splitting (O) plotted against frequency, and NMR spectrum of a single-crystalline high-quality sphere plotted against external field strength in the [111] easy direction ( ) on corresponding horizontal scales (Dormann and Dressel 1989).

Fig. 1.7 29/(D scan from a powder sample prepared from a rock. The amorphous portion of the data (shown in the upper inset graph that covers the 29 range 19-45°) is seen as a hump in the curve. The lower inset diagram is to show that (a) only orientations parallel to the surface are detected in this type of measurement and (b) that the probed volume in the sample (indicated by the double arrows) changes as a function of 29...

PrPtBi Measurements were initially made on powder samples prepared by arc melting (Suzuki et al., 1997). The electrical resistivity ( 1 mf2cm at 300 K) and Hall coefficient ( 0.7 cm /C at low temperatures) are consistent with semiconductivity. The magnetic susceptibility follows the Curie-Weiss law above 50 K but tends to become temperature-independent below 50 K. The specific heat curve shows a prominent anomaly at 1.35 K. A crystalline electric field (CEF) level scheme was derived from inelastic neutron scattering... 

Fig. 192. CUxMxZn2 2iS2 (M=In, Al). Lattice constants vs. composition for powdered samples, prepared by heating pressed mixtures of ZnS, In, Cu and S at 800 °C for 48 h [72 Rob 1].

XRD patterns of the powder samples prepared by the combustion method after calcination are shown in Figure 10. For samples prepared using urea (Figure lOA), XRD patterns are strongly dependent on the fuel/oxide ratio the use of stoichiometric ratio results in a poorly-crystallized sample, with weak diffraction peaks and secondary phases besides LSM. The combustion reaction is far more complete when excess of urea is used, resulting in a crystalline material with single LSM phase formation (ICSD 473444). 

Figure 14 shows the XRD patterns of the LSM powder samples prepared by the citrate method with different CA MI ratios after calcination. The sample prepared with CA MI ratio of 1 exhibited a mixture of phases, which were not identified. This result shows that it is difficult to maintain the homogeneity of the metal ions in the resin on a molecular scale when the CA MI ratio is low. The low concentration of CA prevents a good polymer matrix formation and consequently poor crystalline structures are obtained after calcination, as observed in previous studies [28,29]. 

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