Two-dimensional autocorrelation function analysis of smoked foil patterns

The hydrodynamic lubrication of rough surfaces is analysed with the Reynolds equation, whose application requires the roughness spacing to be large, and the roughness height to be small, compared with the thickness of the fluid film. The general two-dimensional surface roughness is considered, and results applicable to any roughness structure are obtained. It is revealed analytically that two types of term contribute to roughness effects: one depends on the shape of the autocorrelation function and the other does not. The former contribution was neglected by previous workers. The numerical computation of an example shows that these two contributions are comparable in magnitude.

Analysis of the TiO2 Nanotubes Structure Ordering in the Correlation-Spectral Representation

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.386.353 ◽

2018 ◽

Vol 386 ◽

pp. 353-358

Author(s):

Pavel Titov ◽

Svetlana Shchegoleva ◽

Nikolai B. Kondrikov

Keyword(s):

Anodic Oxidation ◽

Autocorrelation Function ◽

Spectral Representation ◽

Fourier Spectrum ◽

Aqueous Electrolytes ◽

Two Dimensional ◽

Quantitative Estimates ◽

Surface Active ◽

Structure Ordering

In the paper, the array ordering of the TiO2nanotubes obtained by method of the anodic oxidation in different modes in the fluorine-containing aqueous-non-aqueous electrolytes containing glycerin as well as the surface-active reagents is considered. It was shown that such characteristics as the two-dimensional Fourier-spectrum, autocorrelation function and its spectrum allow us to identify the ordering nature and to obtain the preliminary quantitative estimates of SEM order.

Synthesis and characterization of two-dimensional Nb4C3 (MXene)

Chemical Communications ◽

10.1039/c4cc03366c ◽

2014 ◽

Vol 50 (67) ◽

pp. 9517-9520 ◽

Cited By ~ 219

Author(s):

M. Ghidiu ◽

M. Naguib ◽

C. Shi ◽

O. Mashtalir ◽

L. M. Pan ◽

...

Keyword(s):

Distribution Function ◽

Hydrofluoric Acid ◽

Pair Distribution Function ◽

Function Analysis ◽

Synthesis And Characterization ◽

Two Dimensional ◽

Phase Pure

By etching Nb4AlC3 powders in hydrofluoric acid, a phase-pure, highly conductive, Nb4C3 MXene – the second with formula M4X3 – was produced. The latter's structure was investigated using pair distribution function analysis.

Ultrasonics in medical diagnosis

Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences ◽

10.1098/rsta.1979.0053 ◽

1979 ◽

Vol 292 (1390) ◽

pp. 187-199 ◽

Cited By ~ 1

Keyword(s):

Blood Flow ◽

Medical Diagnosis ◽

Tissue Characterization ◽

Function Analysis ◽

Doppler Frequency ◽

Two Dimensional ◽

Transfer Function Analysis ◽

Blood Flow Velocities ◽

Tissue Characteristics ◽

Pulse Echo

Beginning with the wave equation, the characteristics of ultrasound are described in terms of propagation, reflexion, beam formation, scattering and attenuation. In medical diagnosis, ultrasound in the low megahertz frequency range is both generated and detected by piezoelectric transducers. At these frequencies the wavelength is in the order of 1 m m ; this is one of the fundamental limitations of attainable resolution. Because attenuation increases with frequency, it is necessary to compromise between resolution and required penetration. The time delays between pulse transmission and echo reception are proportional to the distances between the transducer and the reflectors along the ultrasonic beam. The echo amplitudes are controlled both by the characteristics of the reflectors, and by attenuation in the intervening media. The pulse-echo method is used to produce A-scan, B-scan and C-scan displays. At present the B-scan is the most important. It is used for the study of structure motion by time-position recording, and for tomography by two-dimensional scanning. Grey-scale display gives clues about tissue characteristics. Manually operated, automatic, and very rapid (real-time) two-dimensional scanners are in clinical use, especially in obstetrics and gynaecology, internal medicine and cardiology. The Doppler frequency-shift method is used to detect the movements of structures (especially the foetal heart) and to measure blood flow velocities. Analysis of Doppler blood-flow signals gives data on vessel characteristics. Pulsed Doppler systems can be used to estimate both velocity and position. Newer methods include phase compensation for the distortion otherwise introduced by the skull in brain scanning, tissue characterization, computerized tomography, Doppler blood flow transfer function analysis and tumour detection.

Determination of the normalized surface height autocorrelation function of a two-dimensional randomly rough dielectric surface by the inversion of light scattering data in p-polarization

10.1117/12.2236236 ◽

2016 ◽

Author(s):

J. B. Kryvi ◽

I. Simonsen ◽

A. A. Maradudin

Keyword(s):

Light Scattering ◽

Autocorrelation Function ◽

Dielectric Surface ◽

Scattering Data ◽

Two Dimensional

Time-resolved pair distribution function analysis of disordered materials on beamlines BL04B2 and BL08W at SPring-8

Journal of Synchrotron Radiation ◽

10.1107/s1600577518011232 ◽

2018 ◽

Vol 25 (6) ◽

pp. 1627-1633 ◽

Cited By ~ 14

Author(s):

Koji Ohara ◽

Satoshi Tominaka ◽

Hiroki Yamada ◽

Masakuni Takahashi ◽

Hiroshi Yamaguchi ◽

...

Keyword(s):

Distribution Function ◽

Pair Distribution Function ◽

Structural Changes ◽

Function Analysis ◽

Image Data ◽

High Energy ◽

Disordered Materials ◽

X Rays ◽

Two Dimensional ◽

Time Resolved

A dedicated apparatus has been developed for studying structural changes in amorphous and disordered crystalline materials substantially in real time. The apparatus, which can be set up on beamlines BL04B2 and BL08W at SPring-8, mainly consists of a large two-dimensional flat-panel detector and high-energy X-rays, enabling total scattering measurements to be carried out for time-resolved pair distribution function (PDF) analysis in the temperature range from room temperature to 873 K at pressures of up to 20 bar. For successful time-resolved analysis, a newly developed program was used that can monitor and process two-dimensional image data simultaneously with the data collection. The use of time-resolved hardware and software is of great importance for obtaining a detailed understanding of the structural changes in disordered materials, as exemplified by the results of commissioned measurements carried out on both beamlines. Benchmark results obtained using amorphous silica and demonstration results for the observation of sulfide glass crystallization upon annealing are introduced.

Ordering Сharacteristics of Titanium Dioxide Nanotubes in Anodic Coatings

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.806.39 ◽

2019 ◽

Vol 806 ◽

pp. 39-44 ◽

Cited By ~ 1

Author(s):

Pavel L. Titov ◽

Svetlana A. Shchegoleva ◽

Nikolai B. Kondrikov

Keyword(s):

Autocorrelation Function ◽

Fourier Spectrum ◽

Two Dimensional ◽

Active Materials ◽

Titanium Dioxide Nanotubes ◽

Sufficient Detail ◽

Titanium Oxide Nanotubes ◽

Surface Active ◽

Fourier Spectra ◽

Do It Yourself

In this paper, the ordering of the arrays of TiO2 nanotubes obtained by the method of anodic oxidation in the fluoro-containing aqueous-nonaqueous electrolytes containing glycerine and surface-active materials is investigated. For analysis of ordering, the two-dimensional Fourier spectrum, do-it-yourself configurational geometrical entropy and section of the two-dimensional autocorrelation function were used. These characteristics allow us to identify a nature of ordering in sufficient detail and to obtain the preliminary quantitative assessments of this order. It is found that, in the systems of titanium-oxide nanotubes, the stable, almost correct short-range order is established within the first coordination sphere. Such order is similar to the amorphous ordering. At the same time, the ordering of nanotubes arrays differs in detail from the amorphous one in the greater expressiveness of the typical scale the sizes of which can be estimated using the Fourier spectra as well as autocorrelation function.