Films density measurements

Other SijN samples were CIP ed at different pressures ranging from 5 to 30 K I for density gradient study. The rod densities varied from 1.660 to 1.878 g/cc. Manual microfocus radiography film density measurements done using a densitometer do not show a correlation with the rod density. Further evaluation is underway. 

Modem NDT film systems (with Pb screens) are very linear X-ray detectors. This is shown in fig.l for different NDT film systems and a X-ray tube at 160 kV. Note that for histoncal reasons the film response curve is often plotted as film density versus log (radiation dose), which hides this linear relationship. The film density is the difference between the measured optical film density and the fog density Db of the film base. 

The value for the heat of fusion of PPS, extrapolated to a hypothetical 100% crystalline state, is not agreed upon in the literature. Reported values range from approximately 80 J/g (19 cal/g) (36,96,101) to 146 J/g (35 cal/g) (102), with one intermediate value of 105 J/g (25 cal/g) (20). The lower value, 80 J/g, was originally measured by thermal analysis and then correlated with a measure of crystallinity deterrnined by x-ray diffraction (36). The value of 146 J/g was deterrnined independendy on uniaxiaHy oriented PPS film samples by thermal analysis, density measurement via density-gradient column, and the use of a calculated density for 100% crystalline PPS to arrive at a heat of fusion for 100% crystalline PPS (102). The value of 105 J/g was obtained by measuring the heats of fusion of weU-characterized linear oligomers of PPS and extrapolation to infinite molecular weight. 

Diffraction patterns from thin polycrystalline Ge films were measured by the eleetron diffraetometer. After refinement of scale and thermal factors and corrections for the primary extinetion within the two-beam approximation, the parameters k (spherieal deeompression of valence eleetron shell) and multipoles P32- and P40 (anisotropy of electron density) were ealeulated (Table 4). The residual faetor R ealeulated from the experimental and theoretical amplitudes (the latter were ealeulated by the LAPW method, Lu Z.W., et al. Phys.Rev. 1993, B47, 9385) is 2.07% and proofs the high quality of the experimental. 

Image Quality. Resolution of screens were measured at 50 KV peak x-ray exposures at film densities of 1.0 using standard lead resolution grids with sets of etched lines about I line pair per mm up to 15 line pairs per mm. The results are reported as the maximum set of line pairs resolved per mm. 

Mindt [29] described some properties of these films (thicker electroless films, not the initial purely CD ones). Electron diffraction showed that the film was a-PbOi. The crystal (more correctly the particle) size was found, by electron microscopy, to be ca. 200 nm. The carrier density, measured by the Hall effect, was ca. 10 cm. The resistivity was somewhat dependent on the pH of deposi-... 

Example 13.4. The result of a typical X-ray measurement is shown in Fig. 13.10 for a galactocerebroside [605], The plot on the left side shows the normalized reflected X-ray beam intensity versus the incident angle a for two different film pressures. The pressure-area isotherm is shown in the inset, together with the points of measurement a and b. On the right side are the extracted electron density profiles normal to the film surface taken at the same film pressures. At 0 A we find the monolayer surface (top of the alkyl chains), a depth of -40 A corresponds to pure water. In between is the film. The measurement is so sensitive that we even find two different electron densities within the monolayer. This is illustrated by the dashed boxes denoted by film 1 and film 2 (shown for curve b only) which represents the simplified electron density distribution in the so-called two-box model. A box is defined as a part in the film of a certain thickness where the electron density is constant. In the two-box model the film is divided into two layers. Film 1 represents the hydrocarbon tails, film 2 corresponds to the mean electron density of the head groups. 

The density of the glucan films were measured by flotation in a carbon tetrachloride-m-xylene mixture. 

Recently spin-coated PMMA thin films with a thickness of 0.45 pm on silicon wafer were irradiated with various ion beams (H+, He+, N+, Ni3+). Ion beam energy regions are from 300 keV to 4 MeV. Irradiated PMMA films were developed by isopropyl alcohol in these experiments. After the irradiation by ion beams on PMMA in a vacuum, the thickness of the films were measured both before and after development. Various radiation effects on PMMA films such as ablation (sputtering), main chain scission, and positive-negative inversion were observed as shown in Fig. 11. These phenomena are very different from those in 60 Co gamma-ray or electron beam irradiation. Large LET effects are considered to be due to high density excitation by ion beams. 

By combination of ellipsometry and EQCM Gottesfel [24] studied the nucleation and growth of polyaniline (PANI). The mass deposited was obtained by the frequency change while the thickness resulted from the ellipsometry measurements. Therefore the variations of mass and PANI film density were followed in real time, which would otherwise be impossible with either individual technique alone. 

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