X ray measurements

Combined procedure for uranium concentration and enrichment assay (COMPUCEA) is a transportable system used to perform accurate on-site analytical measurements of elemental 

---

The maximum thickness of X-raying, measured with wire and groove [4] and achieved with a stationary X-ray unit RUP -150/300 for a tube voltage U=250 kV and current 1=1,5 mA was 40 mm for steel. 

Shortcomings of Wang s method like limited pitch of the spiral and blurring in the vertical direction can be improved by the CFBP-algorithm [10], where gaps in the spiral sampling pattern are filled using X-rays measured from the opposite side. 

The only structures definitely established are those obtained from X-ray measurements. Some of these are shown in Table 30, from which a large number of aromatic pyrazole geometries can be found. 

The stability of isothiazole derives from the fact that it has an aromatic delocalized ir-electron system. The NMR chemical shifts, which depend, inter alia, on ring currents, and the high stability of the molecular ions in mass spectrometry, are typical of aromatic compounds, and X-ray measurements confirm the partial double bond character of all the bonds of the ring. 

Since no background correction can be made, dot maps of minor and trace constituents are subject to possible artifacts caused by the dependence of the bremsstrahlung on composition, particularly with EDS X-ray measurement. 

However, Stadler et al. argue that the intensity of the satelhte peaks which would be indicative of the superstructure is so low that they could not possibly be detected in X-ray measurements with the usual experimental resolution. Phases with intermediate tilt directions have been reported [16,17]. 

In both cases, laboratory X-ray sources may be used and the X-ray measurements taken in 0-29 geometry. For weakly scattering systems synchrotron radiation is helpful. 

The X-ray measurements at 1.5, 13, and 30° do, in fact, show a large concentration of molecules at about 4.5 angstroms. This is strong evidence in favor of widespread local tetrahedral arrangement in water at room temperature and below. 

In this sense it should be mentioned that (Ala)n is dissolved by hexafluorisopropanol (HFIP) without conformation change and that stretched fibers of (Leu) shrink in HFIP (20 °C) at about 60 % only by disorientation of (Leu)n molecules, because no conformation change occurs according to X-ray measurements 122,123). An interaction of the OH-group of the alcohol with the back-bone-CO-NH-groups is not very likely because, in this case, conformation changes should be observed. 

The information obtained from X-ray measurements on the arrangement of the water molecules naturally depends very much on the resolution and state of refinement of the crystal structure investigated. For detailed information on the organization of water molecules in the protein hydration shell at the surface and on the bulk water in the crystals a 1,2 to 1,8 A resolution range is necessary 153>. 

X-ray measurements are made by automatic scanning through the peak and adjacent background with recording of the rate-meter output. 

X-rays, measurement of intensity, 42-67 origin, 1-9, 26-34, 101 point sources in various techniques, 292-296... 

It was concluded by Zachariasen [Norsk geol. Tidsskrift, 8, 189 (1925) Z. physik. Chem., 119, 201 (1926)] from the intensities of reflection of x-rays that beryllium oxide does not contain Be++ and O" ions. However, it has since been shown by Claassen [ibid., 124, 139 (1926)] and Zachariasen himself [Z. Physik, 40, 637 (1926)] that if the electron distribution of the ions is taken into account, the x-ray measurements are compatible with an ionic structure. 

An optimal reaction-temperature of 65°C was claimed. The blackish brown TiSCl is very sensitive to oxygen and humidity. As no X-ray measurements have been made, additional work is needed. Titanium sulfide halides have also been claimed as catalysts for the polymerization of propylene (363). 

The nematic phase of all the compounds CBn is characterized by a coherence length of about 1.4 times the elongated structure of the molecule. Based on this behaviour local associations in form of dimers with cyano-phenyl interactions were postulated. For the smectic A phase a partial bilayer arrangement of the molecules (SAd) is most likely. But there are also example for the smectic A phase with a monolayer (Sai) or a bilayer (Sa2) arrangement of the molecules as well as a commensurate structure A large number of X-ray measurements were carried out in the liquid crystalline state to clear up the structural richness and variability (see Chap. 2, this Vol. [52]). 

X-ray measurements have shown that the positional and orientational ordering in highly ordered crystalline smectic phases is more comparable with the ordering in the solid state than the structures of the fluid smectic phases and the nematic phase. Therefore, a comparison of the structures of crystals and highly ordered smectic phases is possible because of their closer similarities. Up to now, only the crystal structures of few mesogenic compounds exhibiting highly ordered smectic phases have been reported in... 

From X-ray measurements in the liquid crystalline phase it is impossible to determine the conformation of the molecules in the condensed state. Computer simulations give us information about the molecules internal freedom in vacuum, but the conformations of the molecules in the condensed state can be different because of intermolecular repulsion or attraction. But it may be assumed that the molecular conformations in the solid state are among the most stable conformations of the molecules in the condensed matter and therefore also among the most probable conformations in the liquid crystalline state. Thus, as more crystallo-graphically independent molecules in the unit cell exist, the more we can learn about the internal molecular freedom of the molecules in the condensed state. 

X-ray measurements of the deposited multilayers revealed practically the same structure in films prepared with the usual LB technique and electric field-assisted monolayer... 

X-ray measurements were carried out with a small-angle diffractometer with a linear position-sensitive detector. Cu Ka radiation (X = 0.154 mn) was used (Mogilevski et al. 1984). The samples were rotated with respect to the incident beam, while the intensity was registered by linear position-sensitive detector. The angular resolution of the detector was 0.01°. The curves were acquired in the 20 range of 0.3-2.0°. X-ray reflection curves are presented in Figures 22 and 23 for wild-type and recombinant proteins, respectively. The... 

TIO is cubic with the NaCl structure. A sample was annealed at 1300 °C. Density and X-ray measurements revealed that the intrinsic defects were Schottlqr in nature (Vxi + Vq) and that their concentration was 0.140. In... 

In practice once a desirable catalyst condition was achieved x-ray measurements often were taken at temperature and after quenching to 90 K In an attempt to minimize thermal smearing of the EXAFS data. 

The x-ray measurements were made at the Stanford Synchrotron Radiation Laboratory which Is supported by DOE. 

Our research in this area was supported by DOE (Grant No. DE-AC02-77ER04254). The X-ray measurements were performed either at the CHESS synchrotron facility, Cornell University, or in the X-ray Diffraction Facility of Northwestern University s Materials Research Center, supported in part by NSF under Grant No. DMR-MRL-76-80897. 

In terms of atomic spectrometry, NAA is a method combining excitation by nuclear reaction with delayed de-excitation of the radioactive atoms produced by emission of ionising radiation (fi, y, X-ray). Measurement of delayed particles or radiations from the decay of a radioactive product of a neutron-induced nuclear reaction is known as simple or delayed-gamma NAA, and may be purely instrumental (INAA). The y-ray energies are characteristic of specific indicator radionuclides, and their intensities are proportional to the amounts of the various target nuclides in the sample. NAA can thus... 

---