Modified Porod's law estimate of the transition-layer thickness between two phases: test of triangular smoothing function

An analytical method to estimate the thickness of the interface between two phases from small-angle scattering (SAS) data has been developed using Porod's law modified by a triangular smoothing function. The convolution with a `top-hat' function describing a sharp density profile results in a semi-sigmoidal density profile. This analytical method allows an interfacial layer thickness to be estimated from the negative slope of a Porod plot. The interfacial layer thickness (T) obtained from this model is related to similar models, namely a linear (E) and a sigmoidal density profile (σ) model, as follows:T= 21/2E= 2(61/2)σ, where σ is the standard deviation of the Gaussian function and does not represent the boundary thickness itself. The interfacial layer thickness obtained from any convolution method is a model-dependent parameter.

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The stabilization of B.C.C. Cu in Cu/Nb nanolayered composites

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100163605 ◽

1996 ◽

Vol 54 ◽

pp. 228-229

Author(s):

H. Kung ◽

A.J. Griffin ◽

Y.C. Lu ◽

K.E. Sickafus ◽

T.E. Mitchell ◽

...

Keyword(s):

Electrical Resistivity ◽

Layer Thickness ◽

Volume Fraction ◽

Ion Beam ◽

High Strength ◽

Cross Sectional ◽

Metastable Structure ◽

High Resolution Tem ◽

Potential Improvement ◽

Two Phases

Materials with compositionally modulated structures have gained much attention recently due to potential improvement in electrical, magnetic and mechanical properties. Specifically, Cu-Nb laminate systems have been extensively studied mainly due to the combination of high strength, and superior thermal and electrical conductivity that can be obtained and optimized for the different applications. The effect of layer thickness on the hardness, residual stress and electrical resistivity has been investigated. In general, increases in hardness and electrical resistivity have been observed with decreasing layer thickness. In addition, reduction in structural scale has caused the formation of a metastable structure which exhibits uniquely different properties. In this study, we report the formation of b.c.c. Cu in highly textured Cu/Nb nanolayers. A series of Cu/Nb nanolayered films, with alternating Cu and Nb layers, were prepared by dc magnetron sputtering onto Si {100} wafers. The nominal total thickness of each layered film was 1 μm. The layer thickness was varied between 1 nm and 500 nm with the volume fraction of the two phases kept constant at 50%. The deposition rates and film densities were determined through a combination of profilometry and ion beam analysis techniques. Cross-sectional transmission electron microscopy (XTEM) was used to examine the structure, phase and grain size distribution of the as-sputtered films. A JEOL 3000F high resolution TEM was used to characterize the microstructure.

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Envisioning the atmospheric effect through (im)materiality

SHS Web of Conferences ◽

10.1051/shsconf/20196402007 ◽

2019 ◽

Vol 64 ◽

pp. 02007

Author(s):

Nilay Ünsal Gülmez ◽

Dürnev Atılgan Yagan ◽

Murat Şahin ◽

Efsun Ekenyazıcı Güney ◽

Hande Tulum

Keyword(s):

Interior Design ◽

Analytical Method ◽

Design Studio ◽

First Year ◽

Second Phase ◽

Design Practice ◽

Atmospheric Effect ◽

Two Phases ◽

Light Color ◽

Design Experiments

In an attempt to bridge the gap between architectural/interior design practice and education, ‘atmosphere’ as a prolific contemporary architectural debate in practice and theory is covered by the experiment of ‘Staging Poe’ carried out as a first year Design Studio through the study of Edgar Allen Poe’s selected poems. Poe’s 1846 text of ‘The Philosophy of Composition’, unfolding his analytical method of writing and emphasis on “effect” in poetry, provides a ground for experimenting with facets of materiality and structuring the studio. Aiming to cultivate intuitive design experiments of students into informed processes in hybridizing conceptual/textual and material/sensual aspects, studio is structured in two phases. In the first phase, “materialization”, idiosyncratic interpretations of students from words to materials with a focus on tectonic experiments and haptic experiences are sought in between materializing and dematerializing processes. In the second phase, the “atmospheric”, emphasis on dematerialization of the perception of materials through tools, such as light, color and sound is exercised to transform the object into a performance stage. Outcomes of the studio on aspects pertaining to material and materialities in creation of the immaterial that is the atmosphere is followed and evaluated through responses of students’ weekly reports.

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Model-independent determination of the surface scattering-length-density profile from specular reflectivity data

Journal of Applied Crystallography ◽

10.1107/s0021889891010907 ◽

1992 ◽

Vol 25 (2) ◽

pp. 129-145 ◽

Cited By ~ 42

Author(s):

J. S. Pedersen

Keyword(s):

Density Profile ◽

Fourier Transformation ◽

Scattering Length ◽

Simulated Data ◽

Limited Range ◽

Square Root ◽

Scattering Length Density ◽

Angle Scattering ◽

Specular Reflectivity ◽

Reflectivity Data

An approach for analysing neutron and X-ray specular reflectivity data from stratified media having variation in the scattering-length density near the surface is described. The method has its origin in small-angle scattering and it is composed of two steps: (i) indirect Fourier transformation [Glatter (1977). J. Appl. Cryst. 10, 415–421] giving the profile correlation function p(z) of the derivative dρ/dz of the scattering-length density; (ii) square-root deconvolution [Glatter (1981). J. Appl. Cryst. 14, 101–108] giving dρ/dz and ρ, the scattering-length-density profile. The only requirement for applying the method is that the scattering-length density varies only in a limited range. In nearly all cases the approach does not require any knowledge of the chemical composition of the surface layer and consequently incorporates a certain degree of objectivity. The method gives the smoothest profile which agrees with the experimental reflectivity data. The method is tested on simulated reflectivity data for a series of different surface profiles and subsequently used for analysing experimental data on fluorocarbon amphiphiles in water and salt solutions. The tests on simulated data show that the indirect Fourier transformation gives correlation functions agreeing very well with the corresponding functions of the original profiles. It is further demonstrated that the square-root deconvolution gives reliable results for the scattering-length-density profiles.

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