X-ray diffraction data and

Some virus particles have their protein subunits symmetrically packed in a helical array, forming hollow cylinders. The tobacco mosaic virus (TMV) is the classic example. X-ray diffraction data and electron micrographs have revealed that 16 subunits per turn of the helix project from a central axial hole that runs the length of the particle. The nucleic acid does not lie in this hole, but is embedded into ridges on the inside of each subunit and describes its own helix from one end of the particle to the other. 

Bisquinolizidine alkaloids have also been widely studied by this technique. For instance, the crystal structure of (—)-A16(17 ,-dehydrolupaninium perchlorate 23 was obtained from sealed-tube and synchroton X-ray diffraction data, and showed that the A, B, C, and D rings assume distorted half-chair, chair, distorted sofa, and chair conformations, respectively it was also used to determine the most precise dimensions so far known for the iminium group <1999JST245>. The crystal structure of quinolizinium hexafluorophosphate has also been studied <2001CSC174>. 

When sodium trimetaphosphate Na3P309 was ground in humid air, the relative volume of the amorphous ingredient (determined from the X-ray diffraction data) and the lattice distortion increased with the duration t of the grinding186. The authors concluded that the variation of Qp was mainly attributable to production of an amorphous material . It is hoped that comparisons similar to those in Motooka s work will be more common in the future. 

From the X-ray diffraction data and the calculated sizes of the dye molecules, the conformation of the dye molecules in the interlayer was briefly estimated. Fig. 1 shows the conformation of the dyes, in which the xanthene nucleus of pyronine or rhodamine was positioned parallel, and the phenyl group of rhodamine perpendicular, to the silicate layers of the clay. 

Combined X-ray and electron diffraction analysis led to an orthorhombic unit-cell, with a = 2.468 mn, 1) = 1.152 nm, and c = 1.054 nm. The space group is P2,2,21. Two parallel chains are related, pairwise, by a two-fold screw-axis parallel to the chain axis, and pairs of chains pack in an antiparallel array. The (110) growth planes ol the crystal are parallel to the direction of highest atomic densities. The transformation CTA II cellulose II was discussed. The R factor is 30% with the X-ray diffraction data, and 26% with the electron diffraction data. 

Detailed analysis of X-ray diffraction data and electron microscope data corresponding to the axial structure of fibrillar collagens has been made. These studies have indicated that the exact molecular periodicity contained 234.2 amino acids per D repeat (Meek et al., 1979). The... 

Figure 7. Scheme for defining and refining fibrous structures using x-ray diffraction data and augmented by stereochemical information... 

The transition band of TiNi (3-d series) bordered by Ms and Mf temperatures are obtained experimentally from a number of Ti (Ni, Co) and Ti (Co, Fe) alloys as shown in Fig. 6. But, the transition band of ZrPd (4-d) series is based on only two X-ray diffraction data and is assumed to be parallel to that of TiNi(3-d) band. It is reasonable, based on these data, to conclude that the crystal structures of the equiatomic compound series of the TiNi, ZrPd, and HfPt are all isotypic and the cause for their diffusionless transition are the same. That is AEd, the d-orbital energy level difference between the two elements change as a function of temperature. It is logical therefore, to conclude that the Nitinol transition is electronic in origin. In order to corroborate this conclusion more data other than crystal structure were obtained as follows. 

A detailed study of the crystal morphology, optical properties, x-ray diffraction data, and fusion data has been reported8 for tetrazolone. 

In the present report we describe initial syntheses in the M20-Si02-Sn02 H20 system. We illustrate how developments in characterization techniques can facilitate the identification of new phases in these types of systems. We mention use of synchrotron X-radiation in microcrystal diffraction experiments, full profile fitting of in-house powder X-ray diffraction data, and infrared and solid state 129Sn and 29Si nmr spectroscopies. 

The compound has been separated into cis and trans forms by chromatography on aluminum oxide. Visible and ultraviolet spectra, x-ray diffraction data, and paramagnetic resonance behavior have been studied. - ... 

We have seen this powder diffraction pattern several times throughout this text. The histogram collected from the nearly spherical LaNi4.85Sno.15 powder, produced by high pressure gas atomization from a melt, was used to illustrate both the quality of x-ray diffraction data and as one of the examples in the ab initio crystal structure solution. To demonstrate the Rietveld refinement of this crystal structure we will begin with the profile and unit cell parameters determined from Le Bail s algorithm Table 6.3) and the model of the crystal structure determined from sequential Fourier maps as described in section 6.9 and listed in Table 6.8. 

A systematic evaluation of the electron donor strengths of different amino groups by using NMR related with UV-Vis, IR and Raman, microwave and photoelectron spectral data, dipole moments, basicity, reactivity, electron and X-ray diffraction data and the results of quantum chemical calculations has been reviewed by Gawinecki and coworkers25. 

Fig. 14. (a) PSDs obtained for MCM-41-type adsorbents from nitrogen and argon DFT porosimetry. (b) Pore wall thickness calculated for five MCM-41 adsorbents using a combination of X-ray diffraction data and N2/Ar adsorption measurements [8]. 

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