Search results for "SMALL-ANGLE NEUTRON"
showing 10 items of 111 documents
Elastic constants in RbI, determined by inelastic neutron scattering
1978
Long-wavelength acoustic phonons have been studied in the whole (100)-plane of RbI at 295 K by means of inelastic neutron scattering. The raw data have been corrected for resolution effects taking into account the curvature of the dispersion surface and variations of the mode eigenvectors. The shifts of the neutron groups due to these resolution effects are discussed in detail. The analysis of the experimental results gives for the zero sound elastic constantsc11=28.15±0.5,c12=3.7±0.5 andc44=2.85±0.1 1010 dyn/cm2. A comparison with first sound elastic constants taken from ultrasonic measurements yields significant differences between the high and low frequency elastic constantsc11 andc″=(c1…
Mode-coupling crossover in viscous toluene revealed by neutron and light scattering
1998
The dynamics of supercooled toluene, studied in a GHz-THz range by incoherent neutron and depolarized light scattering, is found to be in full accord with mode coupling predictions. Around the susceptibility minimum, neutron spectra are wavenumber independent and proportional to light scattering data; the fast β-relaxation scaling law applies; amplitude and frequency diverge with power laws that extrapolate towards a crossover temperature Tc K.
How neutron scattering experiments can target the structure and dynamics of milk proteins?
2016
International audience; The powerful of neutron scattering techniques to characterize structure and dynamics of milk proteins is illustrated. Small angle neutron scattering and reflectivity are used to determine the structure and the interactions between milk proteins in solution, during gelation processes, or the protein structure at different interfaces. Experiments performed by inelastic and quasielastic neutron scattering allow one to observe the dynamics of water and proteins showing the major role of hydration on the dynamics of milk proteins.
Structure of isotactic polypropylene–hydrogenated oligo(cyclopentadiene) (iPP–HOCP) blends Part II. HOCP-rich blends
2000
Abstract Blends of isotactic polypropylene (iPP) and hydrogenated oligo(cyclopentadiene) (HOCP) were investigated to gain structural information by means of both SAXS and SANS techniques. The composition range (from 30 to 60% w/w HOCP content) and the temperature range (between 25 and 160°C) were chosen in order to cover the miscibility gap in the phase diagram of the material system. In a previous report, blends lying outside the miscibility gap have been investigated and the corresponding SAXS patterns were interpreted in terms of a pseudo-two phase model. For the SAXS patterns, blends lying inside the miscibility gap are rather hard to be interpreted in terms of such a model. On the othe…
Calculation of small-angle neutron scattering by macromolecules in the semicrystalline state
1980
The conformation of macromolecules in the semicrystalline state has been studied by various authors with respect to the validity of the adjacent re-entry — or switchboard model by application of small-angle neutron scattering. Analytical as well as Monte-Carlo calculations show that the experimental results for melt crystallized polyethylene and isotactic polypropylene can be interpreted on the basis of the solidification model. In this model it is assumed that crystallization occurs by straightening of coil sequences without a long range diffusion process.
Nucleation and Growth of CaCO3 Mediated by the Egg-White Protein Ovalbumin: A Time-Resolved in situ Study Using Small-Angle Neutron Scattering
2008
Mineralization of calcium carbonate in aqueous solutions starting from its initiation was studied by time-resolved small-angle neutron scattering (SANS). SANS revealed that homogeneous crystallization of CaCO 3 involves an initial formation of thin plate-shaped nuclei which subsequently reassemble to 3-dimensional particles, first of fractal and finally of compact structure. The presence of the egg-white protein ovalbumin leads to a different progression of mineralization through several stages; the first step represents amorphous CaCO 3, whereas the other phases are crystalline. The formation and dissolution of the amorphous phase is accompanied by Ca (2+)-mediated unfolding and cross-link…
Shear induced deformation of polystyrene coils in dilute solution from small angle neutron scattering
1985
The deformation of the overall conformation of polystyrene,Mw=280000 g/ mole in dilute solution in a constant shear gradient has been investigated by small angle neutron scattering (SANS).
A new method for data evaluation of small angle neutron scattering experiments and its application to amorphous polycarbonate
1981
The conformation of single chains in bulk polymer materials can be evaluated from coherent neutron scattering on mixtures of normal and deuterated polymers. It is shown that the single-chain structure factor can be also obtained from measurements of highly concentrated mixtures and the procedure of evaluation is described. The application to amorphous polycarbonate demonstrates the advantages of the method.
Neutron scattering and crystal fields in Pr-hydrides
1978
The crystal field splittings of PrD2 and PrD2.5 have been determined by inelastic neutron scattering. While for PrD2 the crystal field experienced by the majority of Pr-ions is cubic, it is shown that in PrD2.5 the occupation of the octahedral interstitials occurs not in a statistical but rather in a well defined way which leads to an orthorhombic crystal field at the Pr-site.
Experimental studies of the liquid-glass transition in trimethylheptane
2000
The molecular glass former trimethylheptane was studied by calorimetric, dielectric, ultrasonic, neutron scattering, Brillouin scattering, and depolarized light-scattering techniques. The molecular structure appears to be nearly spherical optically as indicated by the low depolarization ratio and dielectric susceptibility values. A preliminary mode-coupling theory (MCT) analysis of the light-scattering and neutron-scattering data indicates that ${T}_{C}\ensuremath{\gtrsim}150 \mathrm{K},$ at least 25 K above ${T}_{G}.$ The susceptibility minima were analyzed with the MCT interpolation equation, and disagreement between the light and neutron results was observed despite the apparent isotropy…