Line radiation 1.12 INDEX

Fig. 6.9. Absorption spectrum between 5 and 11.2 me V of a Ge sample with [Sb] = 8 x 1014 cm-3 at a temperature between 1.7 and 4.2 K. The spectral resolution is 0.14 cm-1 ( 17peV). The lines with indexes (1) and (3) originate from the Is (Ai) and Is (T2) levels, respectively. Band gap radiation reaching the sample explains the sharpness of the lines and the observation of line D of the B acceptor. [15] Copyright 1997, with permission from World Scientific Publishing Co. Pte. Ltd, Singapore...

A number of rotation photographs were made with molybdenum. K-radiation filtered through a zirconium oxide filter to isolate the Ka line. The positions of useful reflections, the indices of the planes producing them, and their visually estimated intensities are given in Table V. The factor placed beside the estimated intensity is a correction for the varying time of reflection, namely Vi — (wl/dsin 20)2, where l is the wave-length, and u and d represent respectively the index of the axis of rotation and the unit translation along it1). (A number of reflections... 

Fig. 5. Relationship between fasting intestinal motility [x-axis migrating motor complex (MMC) index] and bacterial colonization of small bowel in 41 patients with late radiation enteropathy (LRE) is shown by two plots. Relationship to Gram-negative bacilli (a) and to total bacterial count (b) in the duodenum is shown. Note that no significant Gram-negative colonization was found in patients with normal MMC (index = 3). The vertical dotted lines show the normal limit for MMC index. Increased bacterial counts due to URT flora were found in some patients with normal MMC (b). Tied observations are indicated as follows n = 1 n = 2 1 n = 3 1 n = 4 + n = 6 For n > 6...

Work on the structure of crystals and fibers was not the only way in which Mark made use of x-rays. With several collaborators, he reported the results of a number of significant investigations of the physics of x-rays in 1926 and 1927. With Ehrenberg he reported studies of the index of refraction of x-rays, and with Leo Szilard studies verifying the linear polarization of x-rays scattered from electrons at 90. An investigation of the width of x-ray lines was carried out by Mark and Ehrenberg, and Mark and Kallmann reported work on the properties of Compton-scattered x-radiation and on the theory of the dispersion and scattering of x-rays. 

Several octahedral crystals were ground to powder and studied by the Guinier-Hagg technique (Cu radiation). All diffraction lines could be indexed on the basis of a cubic cell with a = 4.560 0.001 A., which is within experimental error of that reported previously for MnSi, 4.558 0.001 A.2 In view of the similarity of the cell constants of the ground crystals to those of previous preparations, significant replacement of manganese by copper is not indicated. This was checked on a few crystals by emission spectrographic analysis which indicated an upper limit of ca. 1% of copper. 

Characterization.— The LSFTO powder was calcined at a series of temperatures (1250, 1300, and 1400°C) in air to investigate phase purity and densification behavior. X-ray diffraction (XRD) powder patterns are shown in Fig. 1. The sample is single phase after heating at 1250°C. At the higher sintering temperatures, the lines become sharper and the density increases. The density measured by the Archimedes method was 90.3% relative to theoretical value after annealing at 1400°C for 10 h. The XRD pattern sintered at 1400°C was completely indexed with a cubic unit cell with lattice parameter a = 3.898(8) A and V= 59.2(6) A3. The weak XRD peaks at 31, 43, 55, and 65° 20 are also from the perovskite phase and arise from a small amount of WL radiation in the incident beam. 

Fig. 2 Dispersion relation for SPP (shown with solid black line) with asymptote at CO cUp/2. As the dispersion of plane wave in dielectric solid gray line) does not cross SPP dispersion, phasematching is not possible - the SPP is a waveguide mode that does not couple to radiation. Dispersion of plane wave in a higher refractive index material dashed black line) is used to obtain phasematching and efficient coupling is obtained at the intersection point with the SPP dispersion...

These data were taken from Kemmit et al. all other cell parameters were obtained in this work from XRDP taken with Cu Ko radiation (Ni filter), the indexing being carried out with the program ERACEL which refines lattice parameters applying a Nelson—Riley extrapolation function. Eight out of 23 lines in the powder pattern of the compound could not be indexed on the basis of a rhombohedral unit cell the authenticity of the compound is therefore doubtful. 

The powder pattern of zinc made with Cu A a radiation (Fig. 3-13) will serve to illustrate how the pattern of a hexagonal substance is indexed. Thirteen lines were observed on this pattern their sin 0 values and relative intensities are listed in Table 10-2. A fit was obtained on a Hull-Davey chart for hexagonal close-packed lattices at an approximate cja ratio of 1.87. The chart lines disclosed the indices listed in the fourth column of the table. In the case of line 5, two chart lines (10- 3 and 11-0) almost intersect at cja = 1.87, so the observed line is evidently the sum of two lines, almost overlapping, one from the (10 3) planes and the other from (11 -0) planes. The same is true of line 11. Four lines on the chart, namely, 20 0, 10 4, 21 -0, and 20 4, do not appear on the pattern, and it must be inferred that these are too weak to be observed. On the other hand, all the observed lines are accounted for, so we may conclude that the lattice of zinc is actually hexagonal close-packed. The next step is to calculate the lattice parameters. Combination of the Bragg law and the plane-spacing equation gives... 

A pattern is made of a cubic substance with unhltered chromium radiation. The observed sin 0 values and intensities are 0.265(m), 0.321(vs), 0.528(w), 0.638(s), 0.793(s), and 0.958(vs). Index these lines and state which are due to Ka and which to Kfi radiation. Determine the Bravais lattice and lattice parameter. Identify the substance by reference to Appendix 5. 

Use the chart constructed in Prob. 10-3 to index the first five lines on the powder pattern of a-titanium. With Cu Ka radiation, these lines have the following sin 0 values 0.091, 0.106, 0.117, 0.200, and 0.268. 

In each of the following problems the powder pattern of an element is represented by the observed sin 9 values of the first seven or eight lines on the pattern, made with Cu Ka radiation. In each case, index the lines, find the crystal system, Bravais lattice, and approx-... 

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