Results 221 to 230 of about 3,891 (249)

Short-time coupled fractional Fourier transform and asymptotic behaviour of distributions

Integral Transforms and Special Functions
Katerina Hadzi-Velkova Sâneva
exaly   +2 more sources

Asymmetric multiple-image encryption based on coupled logistic maps in fractional Fourier transform domain

Optics and Lasers in Engineering, 2014
Abstract A multiple-image encryption scheme is proposed based on the asymmetric technique, in which the encryption keys are not identical to the decryption ones. First, each plain image is scrambled based on a sequence of chaotic pairs generated with a system of two symmetrically coupled identical logistic maps.
Liansheng Sui, Kuaikuai Duan, Junli Liang, Zhiqiang Zhang, Haining Meng   +4 more
openaire   +1 more source

Comprehensive Compositional and Structural Comparison of Coal and Petroleum Asphaltenes Based on Extrography Fractionation Coupled with Fourier Transform Ion Cyclotron Resonance MS and MS/MS Analysis

Energy & Fuels, 2020
A recently developed extrography separation method fractionates petroleum asphaltenes based on their ionization efficiency, which correlates with polarity, aggregation tendency, and asphaltene stru...
Sydney F. Niles, Martha L. Chacón-Patiño, Donald F. Smith, Ryan P. Rodgers, Alan G. Marshall   +4 more
openaire   +1 more source

Online coupling of thermal field-flow fractionation and Fourier transform infrared spectroscopy as a powerful tool for polymer characterization

Journal of Chromatography A, 2019
The rapid growth and increasing importance of complex polymers has accelerated the need for advancement in characterization techniques. The analysis of such materials is challenging and the determination of different molecular parameters requires the combination of different advanced analytical techniques.
N.W. Radebe, T. Beskers, G. Greyling, H. Pasch   +3 more
openaire   +2 more sources

Fractionation of Asphaltene by Adsorption onto Silica and Chemical Characterization by Atmospheric Pressure Photoionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry, Fourier Transform Infrared Spectroscopy Coupled to Attenuated Total Reflectance, and Proton Nuclear Magnetic Resonance

Energy & Fuels, 2016
Asphaltenes are defined as the petroleum fraction insoluble in n-alkanes and soluble in aromatic solvents, such as toluene. Such definition implies that asphaltenes are not a homogeneous material but a mixture of fractions. Asphaltenes represent one of the major contributors to several problematic issues for the petroleum industry.
Priscila T. H. Nascimento, Alexandre F. Santos, Carlos I. Yamamoto, Lilian V. Tose, Eliane V. Barros, Gustavo R. Gonçalves, Jair C. C. Freitas, Boniek G. Vaz, Wanderson Romão, Agnes P. Scheer   +9 more
openaire   +1 more source

Atmospheric Pressure Photoionization Coupled to Fourier Transform Ion Cyclotron Resonance Mass Spectrometry To Characterize Asphaltene Deposit Solubility Fractions: Comparison to Bulk Properties

Energy & Fuels, 2016
In the present work, a field deposit, the solubility fractions, and heptane-precipitated asphaltenes from the crude oil were analyzed using atmospheric pressure photoionization coupled to Fourier transform ion cyclotron resonance mass spectrometry (APPI FT-ICR MS).
Estrella Rogel, Matthias Witt
openaire   +1 more source

Pseudo-differential operators associated with the coupled fractional Fourier transform and its application

Journal of Pseudo-Differential Operators and Applications
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Das, Shraban, Mahato, Kanailal
openaire   +2 more sources

Sample handling and contamination encountered when coupling offline normal phase high performance liquid chromatography fraction collection of petroleum samples to Fourier transform ion cyclotron resonance mass spectrometry

Analytica Chimica Acta, 2012
Normal phase high performance liquid chromatography (HPLC) is used to separate a gas oil petroleum sample, and the fractions are collected offline and analyzed on a high resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometer (FT-ICR MS).
Nicole E, Oro, Randy M, Whittal, Charles A, Lucy   +2 more
openaire   +2 more sources

Atmospheric Pressure Photoionization and Laser Desorption Ionization Coupled to Fourier Transform Ion Cyclotron Resonance Mass Spectrometry To Characterize Asphaltene Solubility Fractions: Studying the Link between Molecular Composition and Physical Behavior

Energy & Fuels, 2015
In the present work, a series of asphaltene solubility fractions extracted from a heavy crude oil have been analyzed using laser desorption ionization (LDI) and atmospheric pressure photoionization (APPI) coupled to Fourier transform ion cyclotron resonance mass spectrometry.
Estrella Rogel, Michael Moir, Matthias Witt   +2 more
openaire   +1 more source

Mathematical analysis of a time-fractional coupled tumour model using Laplace and finite Fourier transforms

Physica Scripta
Abstract A time-fractional diffusive tumour growth model is investigated in this paper. The model assumes two different tumour populations having diverse diffusion and proliferation rates. The classical integer model, coupled with the fractional operators with power-law, Mittag-Leffler and exponential kernels is solved analytically with ...
Sadia Munir, Andrew Omame, Fiazud Din Zaman   +2 more
openaire   +1 more source