Scatter background

Interpretation of the chart utilizes the observation of Andermann and Kemp24 that scattered background and analytical-line intensity decrease in constant ratio as the absorption coefficient of the sample increases. 

The samples have two important characteristics that facilitate these very difficult determinations First, the matrix (all of the sample but the element being determined) is essentially organic matter containing only traces of heavy metals. Second, the samples are of less than critical thickness (6.4). As a consequence, absorption and enhancement effects (7.3) are absent and the scattered background is relatively weak (7.4). 

As a result slow variation of the adjustment is observed the intensity of the primary beam will abnormally increase or decrease, the parasitic scattering background will grow, slit scattering will change (cf. Sect. 4.2.3.7). It should be clear that changes of the primary beam intensity which are paralleled by respective changes of the synchrotron current are normal. 

It is assumed that the machine background has separately been measured and properly been subtracted under consideration of the absorption factor (Sect. 7.6). In particular it is not allowed to take the diffuse scattering background of a molten or amorphous sample for the machine background. 

A. excitation could greatly reduce photolytic interference, nonresonant fluorescence, and scattering backgrounds. The method can be calibrated by fundamental calculation or by ozone photolysis by a shortwave UV source. The successful 2-A determination of NO provides confidence in the fundamental principles of this technique and shows its adaptability for nonsimul-taneous measurements of NO, N02, and HN03. 

A/Q = 3 (tritons), those species with mass-to-charge ratios of 2 or less were reduced by more than 2 orders of magnitude. (Scattered background events limited the measurement of this reduction factor.) This mass-to-charge filtering is particularly important in our future experiments because the protons, deuterons, and alpha particles are produced with yields that are, respectively, 105, 104, and 103 times larger than those of the ions for which measurements are planned. 

However, the presence of lines at 700 cm"1 in the Gd2 sample which are independent on scattering geometry and the existence of the same line at 696 cm 1 in the Gdl spectra both evidence an impurity origin of these excitations. We propose that Co oxides like CoO and Co203 are present at inter crystallite boundaries and on the surface of the none annealed sample Gdl. Such phases could also be the reason for the luminescence observed in the polycrystalline sample G2 seen in Fig.5 as a linear increase of the scattering background. 

Figure 2. IR spectra, in the 3800-3000 cm-1 range, of silicas powders outgassed for 30 min at 423 K (section A) and 773 K (section B) (a) amorphous Aerosil 50 (b) tridymite (c) cristobalite and (d) Qzpl. The spectra are reported after baseline correction to eliminate the sloping scattering background.

The samples for the diffraction experiments were prepared as follows. A crystal of the n-butylammonium vermiculite was cut to a thickness of about 0.5 mm and an area of about 5x5 mm and soaked in the appropriate solution of protonated n-butylammonium chloride in D20. DzO was used because it gave a lower incoherent-scattering background than H20. The gel was allowed to come to its equilibrium swelling distance for 48 hours in a cold room at a temperature of 7°C. A slice of this swollen gel about 1 mm thick was then transferred to a quartz cell of internal dimensions 30 x 5 x 2 mm. The remainder of the quartz cell was filled with some of the original solution. The cell was sealed with Parafilm to prevent loss of solution by evaporation, clamped into an aluminum block, as shown in Figure 1.5, and... 

Separation of the acoustic wavefield into incident and scattered (background... 

Figure 14-1 Separation of the acoustic wavefield into incident and scattered (background and anomalous) parts. The external source is located within some bounded domain Q. The wavespeed is equal to the background velocity everywhere with exception of the local domain D where the velocity is different from the given background values.

Anomalous Scattering Background. The intensity of x-rays scattered from an object can be expressed[37] as ... 

The term Ip/q in Eq. (4.144) accounts for the Porod scattering [104], which is caused by the granular. structure of the CPG-10 and the resulting contrast between the matrix and the liquid in the interstitial space. The term /bg accounts for the noncoherent scattering background resulting from the nondeuterated organic liquid. 

In the second line, the number of refined parameters for a given cycle is specified and, regardless of the pattern s quality, it is always comprised of a continuous scattering background in addition to the diffraction peaks. There are... 

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