Space-resolved patterning

Figure 7 shows an example of a space-resolved microwave conductivity measurement of the semiconducting surface of a natural pyrite (FeS2) sample (from Murgul, Turkey). The overflow of the PMC signal (white color) was adjusted to a level that shows the patterns of distribution of low photoeffects (dark areas). Figure 8 shows a similar image in which,... 

Figure 7. Example of space-resolved photoinduced microwave conductivity mapping of semiconductor interface distribution of photoconductivity in natural pyrite (from Murgul, Turkey, surface etched in acid solution). The overflow was adjusted to show patterns of low photoactivity. For color version please see color plates opposite p. 452.

Princeton Instruments (now Roper Scientific), and was used to store and display the x-ray diffraction data in real time. By incrementally jogging the weld to new locations in 200 pm intervals, a series of space-resolved x-ray diffraction patterns was collected along a lineal scan direction perpendicular to and away from the centerline of the weld. A schematic of the SRXRD setup is shown in Figure 2. Details of the apparatus has been described in detail elsewhere. ... 

Further decrease or increase of the resolution depends on the distribution of events. If there are a very few events, densification of the network would hardly bring to the resolution increase. In contrary, in case of a large amount of sources evenly distributed throughout the study area, the resolved patterns can be smaller than the station spacing. 

There are instances in which one manufacturer may designate a bluish red dye as Red 4B and another manufacturer uses Violet 2R for the same dye. To resolve such a problem the manufacturers pattern leaflets should be consulted. These show actual dyed pieces of cloth so the colors of the dyes in question can be compared directly in the actual appHcation. Alternatively, colors can be specified in terms of color space coordinates. The Cielab system is becoming the standard in this system the color of a dye is defined by three numbers, the L, a, and b coordinates (see Color). 

Interdiffusion of bilayered thin films also can be measured with XRD. The diffraction pattern initially consists of two peaks from the pure layers and after annealing, the diffracted intensity between these peaks grows because of interdiffusion of the layers. An analysis of this intensity yields the concentration profile, which enables a calculation of diffusion coefficients, and diffusion coefficients cm /s are readily measured. With the use of multilayered specimens, extremely small diffusion coefficients (-10 cm /s) can be measured with XRD. Alternative methods of measuring concentration profiles and diffusion coefficients include depth profiling (which suffers from artifacts), RBS (which can not resolve adjacent elements in the periodic table), and radiotracer methods (which are difficult). For XRD (except for multilayered specimens), there must be a unique relationship between composition and the d-spacings in the initial films and any solid solutions or compounds that form this permits calculation of the compo-... 

Measurements of surface disorder require a high resolving power (the ability to distinguish two close-lying points in the diffraction pattern). Quantitative measurements of surface disorder are limited in the following manner, the worse the resolving power, the smaller the maximum scale of surface disorder that can be detected. For example, if the maximum resolvable distance of the diffractometer is 100 A, then a surface that has steps spaced more than 100 A apart will look perfect to the instrument. The theoretical analysis of disorder is much simpler than that for atomic positions. 

Flow inside the capillary membranes, depicted in the lower half of the plot and indicated by positive velocities, shows a regular pattern. The single capillaries are resolved, and flow inside each capillary possesses almost identical maximum velocities. Flow outside the membranes (upper half, negative velocities) reveals a different pattern. Flere, the different flow characteristics between the SMC and SPAN modules become distinct. Obviously, the capillaries in the SMC module are not packed in a regular manner. Large spaces in between the capillaries cause an irregular flow pattern in the dialysate-side with a maximum velocity of about -15 mm s-1 (Figure 4.6.2(a)), which is comparable to the maximum velocity in... 

The following data describe the pattern for dobutamine hydrochloride, where d is equal to the interplanar spacing measured in terms of Angstroms (A). The ratio I/It is the intensity of the X-ray maxima based upon a value of 100 for the strongest line. A b indicates a broad line resulting from failure to resolve two closely spaced diffraction maxima. 

SEM-EDS. All the samples of fresh ochre-precipitates exhibit XRD patterns typical of poorly crystalline material, such as ferrihydrite (Schwertmann Cornell 2000). They present the strongest band centred at 2.56A, corresponding to the (110) reflection of 6-line ferrihydrite, as well as the characteristic poorly resolved reflections at d spacings 1.47 - 1.73 - 1.98 and 2.24k. 

After 45 days of experiment, the precipitate showed an XRD pattern typical of a poorly ordered mineral, such as schwertmannite. Identification of this AMD mineral was confirmed by its distinctive spike morphology, observed by SEM-SE (Fig. 3). After 240 days, XRD detected the resolved reflection at d spacing of 4.18 A, which is characteristic of goethite. Therefore, the maintenance of the precipitate in contact with the solution enabled its evolution to a more crystalline state. The trend of decrease in pH that is observed by the end of the experiment reflects the production of acidity, associated with the transformation of schwertmannite into goethite as it was observed by Bigham etal. (1996) (eq. 1). 

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