共查询到20条相似文献,搜索用时 15 毫秒
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The small-angle x-ray scattering (SAXS) resulting from a non-ideal two-phase system having sharply defined phase boundaries but with micro-fluctuations of electron density within any phase shows a positive deviation from Debye's theory. We have found a simple method suitable for fitting the slit-smeared SAXS data and correcting the positive deviation. The validity of this procedure is tested on porous ZrO_2 xerogel prepared using the sol-gel process. 相似文献
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M. Sztucki E. Di Cola T. Narayanan 《The European physical journal. Special topics》2012,208(1):319-331
A review of recent applications of Anomalous Small-Angle X-ray Scattering (ASAXS) to charged soft matter systems is presented.
Although the potential of ASAXS was realized in the eighties [1], applications to soft matter systems became feasible in recent
years thanks to the technical developments at the synchrotron sources. Examples include both stiff chain and flexible polyelectrolytes,
colloidal brush-like polyelectrolytes, DNA, RNA, and polysaccharides where the counterion profile could be determined with
high precision and compared with theoretical models. In addition, ASAXS has also been found useful for microstructure characterization
in soft materials. Finally, the present capability for ASAXS studies is illustrated by an example involving a surfactant micellar
system. 相似文献
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Pautrat A Goupil C Simon Ch Charalambous D Forgan EM Lazard G Mathieu P Brûlet A 《Physical review letters》2003,90(8):087002
We report small-angle neutron scattering measurements on the vortex lattice in a PbIn polycrystal in the presence of an applied current. Using the rocking curves as a probe of the distribution of current in the sample, we observe that vortex pinning is due to the surface roughness. This leads to a surface current that persists in the flux-flow region. We show the influence of surface treatments on the distribution of this current. 相似文献
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Yu. V. Kul’velis S. V. Kononova K. A. Romashkova V. T. Lebedev 《Physics of the Solid State》2014,56(1):86-90
The structure of gradient-porous (asymmetric) membranes based on polyamide imide at different conditions of their formation has been investigated using small-angle neutron scattering. It has been shown that the membranes consist of rigid porous networks with well-defined interfaces between the polymer and the pores. It has been found that there are differences in the packings of structural elements of porous membranes-spherical pores with radii from 4 to 100 nm—depending on the membrane preformation time, drying regime, and the presence of fullerene C60 for modifying the mechanical and selective properties of membranes. The membranes also contain larger pores of micrometer sizes. Differences in the rates of saturation of membranes with water and their limiting swelling ratios are found, which can be explained by the structure of the dense layers of membranes (skin layer) and their different hydrophilities (depending on the fullerene content). 相似文献
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Gernot Kostorz 《Hyperfine Interactions》1989,45(1-4):91-103
The basic principles of neutron and x-ray small-angle scattering are briefly outlined. Applications of the technique to study
the decomposition kinetics of alloys, precipitate shapes and precipitate interactions are discussed, summarising results for
Al- and Ni-base alloys. 相似文献
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Stefan Odenbach Dietmar Schwahn Klaus Stierstadt 《Zeitschrift für Physik B Condensed Matter》1995,96(4):567-569
Isothermal convection in ferrofluids has been induced by a gradient in particle concentration antiparallel to a magnetic field gradient. The deviation of local particle concentration from its equilibrium value produced by the convective motion of the whole fluid gives rise to a corresponding spatial variation of magnetization. This variation has been observed by magnetic neutron scattering in good agreement with expectations based on flow measurements with an anemometric method. 相似文献
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A. V. Nagornyi V. I. Petrenko M. V. Avdeev L. A. Bulavin V. L. Aksenov 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2010,4(6):976-981
The possibility to conduct the experiment on small-angle neutron scattering on very dilute magnetic fluids (the volume fraction
of magnetite is ∼0.1%) is discussed. The aim of these experiments is to determine the structural parameters of these fluids
using the Guinier approximation. Primary attention is concentrated on the experimental observation of a nonmagnetic layer
on the surfaces of magnetic nanoparticles dispersed in a liquid carrier. Significant parameters are determined, and conditions
for the experiment on the contrast variation are chosen in model calculations. 相似文献
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A. V. Nagornyi V. I. Petrenko L. A. Bulavin M. V. Avdeev L. Almásy L. Rosta V. L. Aksenov 《Physics of the Solid State》2014,56(1):91-96
Structural parameters of the magnetite-oleic acid-decalin magnetic fluid at various excesses of oleic acid (up to 25 vol %) have been determined using small-angle neutron scattering. Based on the comparison of the behavior of oleic acid in the magnetic fluid and in the pure solvent (decalin), it has been concluded that the interaction between the molecules of free (unadsorbed) surfactant changes in the presence of magnetic nanoparticles. However, the system remains stable and does not form aggregates of magnetic particles or free oleic acid. These results are compared with the previously presented data for similar benzene-based magnetic fluids. 相似文献
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Prof. A. B. Pippard 《Zeitschrift für Physik B Condensed Matter》1969,9(1-2):71-72
Small-angle scattering can produce significant effects when the Fermi surface is able to provide both electron and hole orbits
in a magnetic field. These orbits may run close to one another ink-space so that scattering through a small angle is sufficient to change the path of an electron radically. Simple models of
the phenomenon will be described and their calculated behaviour compared with experimental results.
This work has been published in Proc. Roy. Soc.A 305, 291 (1968). 相似文献
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The dependence of the spectra of small-angle multiple neutron scattering on the volume fraction occupied by scattering grains is considered. The concentration expansion is used to develop scattering theory in the eikonal approximation. The leading term of the expansion reproduces the standard low-concentration theory (Mollier). Some properties of the first correction term are analyzed, and it is shown that the angular distribution narrows with an increase in concentration, in qualitative agreement with the experimental data. 相似文献
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D.?Honecker A.?Ferdinand F.?D?brich C. D.?Dewhurst A.?Wiedenmann C.?Gómez-Polo K.?Suzuki A.?Michels 《The European Physical Journal B - Condensed Matter and Complex Systems》2010,76(2):209-213
Due to recent progress in the development of 3He spin filters, it has only now become possible to perform routinely longitudinal (one-dimensional) neutron-spin analysis
(POLARIS) in small-angle neutron scattering (SANS) experiments. It is the purpose of this article to provide a brief introduction
into the technique and to discuss first experimental data. In particular, for the most common scattering geometry where the
applied magnetic (guide) field is perpendicular to the incident neutron beam, we write down the equations for the non-spin-flip
and spin-flip SANS cross sections of a bulk ferromagnet, and we discuss the various angular anisotropies and asymmetries along
with some selected experimental results on an FeCr based soft magnetic nanocrystalline alloy. In particular, we show that
the analysis of the spin-flip data allows one to obtain the magnitude-squares of the three vector (Fourier) components of
the magnetization. 相似文献
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V. I. Petrenko M. V. Avdeev V. M. Garamus M. Kubovcikova Z. Gažová K. Šipošová L. A. Bulavin L. Almásy V. L. Aksenov P. Kopcansky 《Physics of the Solid State》2014,56(1):129-133
The structure of filament amyloid aggregates of hen egg white lysozyme in water has been investigated by the small-angle X-ray scattering method. The experimental data are described by different cylindrical models, among which the best agreement is reached with the long helix model. A comparison of the results with the small-angle neutron scattering data reveals the influence of the heavy component of the solvent (a H2O/D2O mixture) on the structure of the filaments. 相似文献
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In amorphous Fe40Ni40C14P6 alloys the field dependence of the magnetic scattering cross section and the analysis of the scattering profile indicate the presence of stress centres corresponding to quasidislocation dipoles. 相似文献
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D. Sen J. Bahadur S. Mazumder 《The European Physical Journal B - Condensed Matter and Complex Systems》2009,71(1):75-84
Present work involves extraction of single-scattering profile from
small-angle scattering data, affected by multiple scattering, using an
existing model-independent algorithm [Mazumder et al., Physica B 241–243,
1222 (1998), Mazumder et al., J. Appl. Crystallogr. 36, 840 (2003)]. It is shown that
implementation of the algorithm becomes effective by representing the
multiple scattering profiles in terms of a set of basis function whose form
of Hankel transformed pair is known analytically. In the present paper, the
methodology has been presented by introducing a Gaussian basis set and has
been tested for various simulated profiles. The performance of this
methodology has also been tested for scattering profiles having complex
internal features and moderate statistical noise. Subsequently, the same has
been applied for experimental small-angle neutron scattering data. 相似文献