Neutron scattering measurement

The polymer concentration profile has been measured by small-angle neutron scattering from polymers adsorbed onto colloidal particles [70,71] or porous media [72] and from flat surfaces with neutron reflectivity [73] and optical reflectometry [74]. The fraction of segments bound to the solid surface is nicely revealed in NMR studies [75], infrared spectroscopy [76], and electron spin resonance [77]. An example of the concentration profile obtained by inverting neutron scattering measurements appears in Fig. XI-7, showing a typical surface volume fraction of 0.25 and layer thickness of 10-15 nm. The profile decays rapidly and monotonically but does not exhibit power-law scaling [70]. 

C. Incoherent Neutron Scattering Measurements of Lipid Dynamics... 

Thus, the starting parameters for the computer-simulation of spectrum IB were chosen to agree with the value of hyperfine fields at 613 K as measured by Rlste and Tenzer, using neutron scattering measurements (36). In addition, the magnetic relaxation rate depends on temperature, as discussed in the Theory section of this paper. 

Small angle neutron scattering measurements were carried out with the PACE diffractometer at the Laboratoire Leon Brillouin, (CE Saclay, France). The q range observed was 3.4 lO" to 0.2 A l. Samples were prepared in deuterated instead of ordinary water to achieve a suitable value for the neutron contrast factor. 

When the various results obtained by combined elastic and quasielastic neutron scattering measurements on star shaped polymers in dilute solutions... 

The Debye temperatures of stages two and one were determined by inelastic neutron scattering measurements [33], The total entropy variation using equation 8 is in the order of about 2 J/(mol.K). Although smaller in value, such variation accounts for 10-15% of the total entropy and should not be neglected. We are currently carrying on calculations of the vibrational entropy from the phonon density of states in LixC6 phases. 

In t-DVB/S copolymerization, Antonietti and Rosenauer isolated microgels slightly below the macrogelation point [221]. Using small angle neutron scattering measurements they demonstrated that these microgels exhibit fractal behavior, i.e. they are self-similar like the critically branched structures formed close to the sol-gel transition. 

The structure of the adsorbed ion coordination shell is determined by the competition between the water-ion and the metal-ion interactions, and by the constraints imposed on the water by the metal surface. This structure can be characterized by water-ion radial distribution functions and water-ion orientational probability distribution functions. Much is known about this structure from X-ray and neutron scattering measurements performed in bulk solutions, and these are generally in agreement with computer simulations. The goal of molecular dynamics simulations of ions at the metal/water interface has been to examine to what degree the structure of the ion solvation shell is modified at the interface. 

From neutron scattering measurements using different concentrations of D2O, an independent molecular weight estimate of 40.8 x 10 has been derived (Jacrot et al., 1983). 

Hammermann, M., Brun, N., Klenin, K.V., May, R., Toth, K., and Langowski, J. (1998) Salt-dependent DNA superhelix diameter studied by small angle neutron scattering measurements and Monte Carlo simulations. Biophys. J. 75, 3057-3063. 

In order to determine the dynamics of atoms we have to carry out an inelastic neutron scattering measurement. With a reactor source this can be done with a triple-axis spectrometer, which has an analyzer crystal. Tripleaxis refers to the three axes for the monochromator, sample, and analyzer, all moving independently and controlled by a computer. With a pulsed source we use a mechanical chopper, which is a rotating cylinder with a hole perpendicular to the rotating axis that allows neutrons with a chosen range of velocity to go through. The neutrons scattered by the sample are detected... 

As already described, the upper three portions of Figure 2 summarize the differences in the way the constraints are applied in the constrained-junction theory, constrained-chain theory, and the diffused-constraints theory, respectively [4], Additional comparisons between theory and experiment for a variety of elastomeric properties should be very helpful [20], Also, neutron-scattering measurements conducted on series of networks having different values of the junction functionality , which is the number of chains emanating from a junction (cross-link), would be extremely useful in suggesting how to position the constraints along a chain in refining such models, since should have a pronounced effect on the... 

Table 1. Experimental results of neutron scattering measurements on PS networks with deuterated crosslinks...

Not any feature was observed in the single-magnon dispersion that would correlate with the lower-energy two-magnon peak in the inelastic neutron scattering measurements of the stripe-ordered nickelate Lai.69Sr0.3iNiC>4 also.311... 

Engelman, D. M., Moore, P. B., and Schoenbom, B. P. (1975). Neutron-scattering measurements of separation and shape of proteins in 30s ribosomal-subunit of Escherichia coli—S2-S5, S5-S8, S3-S7. Proc. Natl Acad. Sci. USA 72, 3888-3892. 

Recent neutron scattering measurements [25] have revealed a well-defined fe (TO) soft mode in pmn at high temperatures that becomes overdamped by the polar nanoregions below the Burns temperature, Td. Thus, while the soft mode below Td is not a well-defined excitation in the spectrum, the large value of e and its strong temperature and pressure dependences between Td and Tm clearly implicate low-lying optic mode excitations. 

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