Small-angle X-ray scattering from spherical particles of non-uniform electron density

1974 ◽  
Vol 7 (2) ◽  
pp. 211-218 ◽  
Author(s):  
K. Kranjc
1989 ◽  
Vol 56 (3) ◽  
pp. 443-451 ◽  
Author(s):  
Helmut Pessen ◽  
Thomas F. Kumosinski ◽  
Harold M. Farrell

SummarySmall-angle X-ray scattering was performed on whole casein under submicellar (Ca2+ removed) and micellar (Ca2+ re-added) conditions. Submicellar scattering curves showed two Gaussian components which were interpreted in terms of a spherical particle with two concentric regions of different electron density, a relatively compact core of higher electron density and a looser shell. Normalized scattering curves and calculated distance distribution functions were consistent with this picture. Micellar scattering data, which can yield only cross-sectional information related to a window of scattered intensities, could be analysed by a sum of three Gaussians with no residual function. The two Gaussians with the lower radii of gyration were again taken to indicate the two concentric regions of different electron density of inhomogeneous spherical particles; the third Gaussian was shown to reflect the packing number of these particles within a cross-sectional portion of the micelle, which was 3:1 for this system. These results are a strong indication that submicellar inhomogeneous particles containing hydrophobically stabilized inner cores exist within the colloidal micelle.


1968 ◽  
Vol 12 ◽  
pp. 87-96
Author(s):  
R. W. Gould ◽  
S. R. Bates

AbstractIt has been recently shown that particle size distributions can be determined from small angle x-ray scattering data. Size distributions have previously been measured in aluminum-zinc and aluminum-silver alloys containing spherical Guinier-Preston zones. Inorder to obtain the size distribution it is only necessary to calculate the Guinier radius and the Porod radius.Dispersion hardened nickel alloys containing small spherical particles of thoria appear to be amenable to this type of analysis. A nickel-20% chromium-2% ThO2 alloy was selected for this study. The particle size distribution obtained by small angle x-ray scattering is compared with the transmission electron microscopy results found in the literature.


1976 ◽  
Vol 31 (5-6) ◽  
pp. 238-244 ◽  
Author(s):  
Johann Berger ◽  
Ingrid Pilz ◽  
Raf Witters ◽  
René Lontie

The α -haemocyanin molecules of Helix pomatia were decomposed into halves and studied in solution by small-angle X-ray scattering. The following parameters of the molecule could be ob­tained : radius of gyration, volume, molecular weight, overall shape and dimensions of the molecule. With small-angle X-ray scattering fluctuations of the electron density within the protein cause parasitic scattering at larger angles. According to Stuhrmann and Kirste it is possible to eliminate it mathematically by varying the electron density of the buffer. For this purpose different quan­tities of glycerol respectively saccharose were added to the solvent to study the scattering of α -haemocyanin halves in solvents of varied electron density. The change of the isopotential specific volume of haemocyanin and the strong increase of the statistical errors of its scattering by de­creasing of the excess scattering of solution over solvent per unit volume did not allow an ap­plication of the method of Stuhrmann and Kirste. The data obtained for α -haemocanin halves in different solvents are given. Besides also the sedimentation of the α -haemocyanin halves were studied in solutions containing varied amounts of glycerol and saccharose. An attempt was made to calculate the change of the partial specific volume of haemocyanin by adding glycerol or saccharose.


2015 ◽  
Vol 48 (1) ◽  
pp. 20-28 ◽  
Author(s):  
Raul Garcia-Diez ◽  
Christian Gollwitzer ◽  
Michael Krumrey

Many low-density nanoparticles show a radial inner structure. This work proposes a novel approach to contrast variation with small-angle X-ray scattering based on the constitution of a solvent density gradient in a glass capillary in order to resolve this internal morphology. Scattering curves of a polymeric core–shell colloid were recorded at different suspending medium contrasts at the four-crystal monochromator beamline of PTB at the synchrotron radiation facility BESSY II. The mean size and size distribution of the particles as well as an insight into the colloid electron density composition were determined using the position of the isoscattering points in the Fourier region of the scattering curves and by examining the Guinier region in detail. These results were corroborated with a model fit to the experimental data, which provided complementary information about the inner electron density distribution of the suspended nanoparticles.


2007 ◽  
Vol 40 (3) ◽  
pp. 496-504 ◽  
Author(s):  
Byeongdu Lee ◽  
Insun Park ◽  
Haewoong Park ◽  
Chieh-Tsung Lo ◽  
Taihyun Chang, ◽  
...  

The electron density map of a block copolymer thin film having the hexagonally perforated layer (HPL) structure was directly obtained from the measured grazing-incidence small-angle X-ray scattering (GISAXS) pattern, exploiting the multiple-scattering phenomena present in GISAXS. It is shown that GISAXS is in principle equivalent to three-beam diffraction, which has been used to extract phases of diffraction peaks. In addition, X-ray reflectivity analysis has been performed which, when combined with the GISAXS results, provides full details of the HPL structure.


1979 ◽  
Vol 22 (8) ◽  
pp. 846-851
Author(s):  
M. Ya. Fuks ◽  
P. G. Cheremskoi ◽  
O. G. Alaverdova ◽  
L. P. Shpakovskaya

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