WorldWideScience

Sample records for fourier transform spectrometry

  1. Fourier Transform Mass Spectrometry

    Science.gov (United States)

    Scigelova, Michaela; Hornshaw, Martin; Giannakopulos, Anastassios; Makarov, Alexander

    2011-01-01

    This article provides an introduction to Fourier transform-based mass spectrometry. The key performance characteristics of Fourier transform-based mass spectrometry, mass accuracy and resolution, are presented in the view of how they impact the interpretation of measurements in proteomic applications. The theory and principles of operation of two types of mass analyzer, Fourier transform ion cyclotron resonance and Orbitrap, are described. Major benefits as well as limitations of Fourier transform-based mass spectrometry technology are discussed in the context of practical sample analysis, and illustrated with examples included as figures in this text and in the accompanying slide set. Comparisons highlighting the performance differences between the two mass analyzers are made where deemed useful in assisting the user with choosing the most appropriate technology for an application. Recent developments of these high-performing mass spectrometers are mentioned to provide a future outlook. PMID:21742802

  2. Fourier Transform Mass Spectrometry.

    Science.gov (United States)

    Gross, Michael L.; Rempel, Don L.

    1984-01-01

    Discusses the nature of Fourier transform mass spectrometry and its unique combination of high mass resolution, high upper mass limit, and multichannel advantage. Examines its operation, capabilities and limitations, applications (ion storage, ion manipulation, ion chemistry), and future applications and developments. (JN)

  3. Fourier transform ion cyclotron resonance mass spectrometry

    Science.gov (United States)

    Marshall, Alan G.

    1998-06-01

    As for Fourier transform infrared (FT-IR) interferometry and nuclear magnetic resonance (NMR) spectroscopy, the introduction of pulsed Fourier transform techniques revolutionized ion cyclotron resonance mass spectrometry: increased speed (factor of 10,000), increased sensitivity (factor of 100), increased mass resolution (factor of 10,000-an improvement not shared by the introduction of FT techniques to IR or NMR spectroscopy), increased mass range (factor of 500), and automated operation. FT-ICR mass spectrometry is the most versatile technique for unscrambling and quantifying ion-molecule reaction kinetics and equilibria in the absence of solvent (i.e., the gas phase). In addition, FT-ICR MS has the following analytically important features: speed (~1 second per spectrum); ultrahigh mass resolution and ultrahigh mass accuracy for analysis of mixtures and polymers; attomole sensitivity; MSn with one spectrometer, including two-dimensional FT/FT-ICR/MS; positive and/or negative ions; multiple ion sources (especially MALDI and electrospray); biomolecular molecular weight and sequencing; LC/MS; and single-molecule detection up to 108 Dalton. Here, some basic features and recent developments of FT-ICR mass spectrometry are reviewed, with applications ranging from crude oil to molecular biology.

  4. Differentiating Fragmentation Pathways of Cholesterol by Two-Dimensional Fourier Transform Ion Cyclotron Resonance Mass Spectrometry.

    Science.gov (United States)

    van Agthoven, Maria A; Barrow, Mark P; Chiron, Lionel; Coutouly, Marie-Aude; Kilgour, David; Wootton, Christopher A; Wei, Juan; Soulby, Andrew; Delsuc, Marc-André; Rolando, Christian; O'Connor, Peter B

    2015-12-01

    Two-dimensional Fourier transform ion cyclotron resonance mass spectrometry is a data-independent analytical method that records the fragmentation patterns of all the compounds in a sample. This study shows the implementation of atmospheric pressure photoionization with two-dimensional (2D) Fourier transform ion cyclotron resonance mass spectrometry. In the resulting 2D mass spectrum, the fragmentation patterns of the radical and protonated species from cholesterol are differentiated. This study shows the use of fragment ion lines, precursor ion lines, and neutral loss lines in the 2D mass spectrum to determine fragmentation mechanisms of known compounds and to gain information on unknown ion species in the spectrum. In concert with high resolution mass spectrometry, 2D Fourier transform ion cyclotron resonance mass spectrometry can be a useful tool for the structural analysis of small molecules. Graphical Abstract ᅟ.

  5. ENVIRONMENTAL ANALYSIS BY AB INITIO QUANTUM MECHANICAL COMPUTATION AND GAS CHROMATOGRAPHY/FOURIER TRANSFORM INFRARED SPECTROMETRY.

    Science.gov (United States)

    Computational chemistry, in conjunction with gas chromatography/mass spectrometry/Fourier transform infrared spectrometry (GC/MS/FT-IR), was used to tentatively identify seven tetrachlorobutadiene (TCBD) isomers detected in an environmental sample. Computation of the TCBD infrare...

  6. Capillary supercritical fluid chromatography - Fourier transform infrared spectrometry

    International Nuclear Information System (INIS)

    Olesik, S.V.; French, S.B.; Movotny, M.

    1984-01-01

    One of the most demanding tasks asked of an analytical chemist today is to separate and identify the components of a nonvolatile complex mixture. An efficient separation technique combined with a universal detector that provides structural information, therefore, would be a great asset to analytical chemists. Capillary supercritical fluid chromatography (SFC) - Fourier transform infrared spectrometry (FTIR) shows great potential for being such a technique. SFC-FTIR shows great potential as a very powerful technique for separation and identification of thermally labile and nonvolatile compounds. Research is continuing in these labs to further optimize the technique. 2 refs

  7. Fourier Transform Mass Spectrometry: The Transformation of Modern Environmental Analyses

    Science.gov (United States)

    Lim, Lucy; Yan, Fangzhi; Bach, Stephen; Pihakari, Katianna; Klein, David

    2016-01-01

    Unknown compounds in environmental samples are difficult to identify using standard mass spectrometric methods. Fourier transform mass spectrometry (FTMS) has revolutionized how environmental analyses are performed. With its unsurpassed mass accuracy, high resolution and sensitivity, researchers now have a tool for difficult and complex environmental analyses. Two features of FTMS are responsible for changing the face of how complex analyses are accomplished. First is the ability to quickly and with high mass accuracy determine the presence of unknown chemical residues in samples. For years, the field has been limited by mass spectrometric methods that were based on knowing what compounds of interest were. Secondly, by utilizing the high resolution capabilities coupled with the low detection limits of FTMS, analysts also could dilute the sample sufficiently to minimize the ionization changes from varied matrices. PMID:26784175

  8. Fourier Transform Mass Spectrometry: The Transformation of Modern Environmental Analyses

    Directory of Open Access Journals (Sweden)

    Lucy Lim

    2016-01-01

    Full Text Available Unknown compounds in environmental samples are difficult to identify using standard mass spectrometric methods. Fourier transform mass spectrometry (FTMS has revolutionized how environmental analyses are performed. With its unsurpassed mass accuracy, high resolution and sensitivity, researchers now have a tool for difficult and complex environmental analyses. Two features of FTMS are responsible for changing the face of how complex analyses are accomplished. First is the ability to quickly and with high mass accuracy determine the presence of unknown chemical residues in samples. For years, the field has been limited by mass spectrometric methods that were based on knowing what compounds of interest were. Secondly, by utilizing the high resolution capabilities coupled with the low detection limits of FTMS, analysts also could dilute the sample sufficiently to minimize the ionization changes from varied matrices.

  9. Atmospheric pressure chemical ionization Fourier transform ion cyclotron resonance mass spectrometry for complex thiophenic mixture analysis

    KAUST Repository

    Hourani, Nadim; Andersson, Jan T.; Mö ller, Isabelle; Amad, Maan H.; Witt, Matthí as; Sarathy, Mani

    2013-01-01

    oil (VGO) and injected using the same method. The samples were analyzed using Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS). RESULTS PASH model analytes were successfully ionized and mainly [M + H]+ ions were produced. The same

  10. Analysis of cigarette smoke by Fourier transform infrared spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Maddox, W.L. (Oak Ridge National Lab., TN); Mamantov, G.

    1977-02-01

    The application of Fourier transform infrared spectrometry (FT-IR) to the quantitative determination of several components in the gas phase of whole, dilute tobacco smoke was demonstrated. The 18-cm absorption cell was part of a cigarette smoking system similar to the intermittent inhalation exposure devices used in smoking and health research with rodents. Concentrations were measured for carbon monoxide, carbon dioxide, methane, ethylene, and methanol in 7 to 22% smoke. The precision of a measurement in 22% smoke ranged from 3% for carbon dioxide to 34% for ethylene. Absorbances measured for isoprene and hydrogen cyanide followed expected concentrations in different cigarette smokes. It was shown that the concentrations of these components remain constant during a 30-s hold-up following each puff on the cigarettes.

  11. Electrostatic ion trap and Fourier transform measurements for high-resolution mass spectrometry

    International Nuclear Information System (INIS)

    Bhushan, K. G.; Gadkari, S. C.; Yakhmi, J. V.; Sahni, V. C.

    2007-01-01

    We report on the development of an electrostatic ion trap for high-resolution mass spectrometry. The trap works on purely electrostatic fields and hence trapping and storing of ions is not mass restrictive, unlike other techniques based on Penning, Paul, or radio frequency quadrupole ion traps. It allows simultaneous trapping and studying of multiple mass species over a large mass range. Mass spectra were recorded in ''dispersive'' and ''self-bunching'' modes of ions. Storage lifetimes of about 100 ms and mass resolving power of about 20 000 could be achieved from the fifth harmonic Fourier transform spectrum of Xe ions recorded in the self-bunching mode

  12. Approximating the Analytic Fourier Transform with the Discrete Fourier Transform

    OpenAIRE

    Axelrod, Jeremy

    2015-01-01

    The Fourier transform is approximated over a finite domain using a Riemann sum. This Riemann sum is then expressed in terms of the discrete Fourier transform, which allows the sum to be computed with a fast Fourier transform algorithm more rapidly than via a direct matrix multiplication. Advantages and limitations of using this method to approximate the Fourier transform are discussed, and prototypical MATLAB codes implementing the method are presented.

  13. Identification of chemical components in Baidianling Capsule based on gas chromatography-mass spectrometry and high-performance liquid chromatography combined with Fourier transform ion cyclotron resonance mass spectrometry.

    Science.gov (United States)

    Wu, Wenying; Chen, Yu; Wang, Binjie; Sun, Xiaoyang; Guo, Ping; Chen, Xiaohui

    2017-08-01

    Baidianling Capsule, which is made from 16 Chinese herbs, has been widely used for treating vitiligo clinically. In this study, the sensitive and rapid method has been developed for the analysis of chemical components in Baidianling Capsule by gas chromatography-mass spectrometry in combination with retention indices and high-performance liquid chromatography combined with Fourier transform ion cyclotron resonance mass spectrometry. Firstly, a total of 110 potential volatile compounds obtained from different extraction procedures including alkanes, alkenes, alkynes, ketones, ethers, aldehydes, alcohols, phenols, organic acids, esters, furans, pyrrole, acid amides, heterocycles, and oxides were detected from Baidianling Capsule by gas chromatography-mass spectrometry, of which 75 were identified by mass spectrometry in combination with the retention index. Then, a total of 124 components were tentatively identified by high-performance liquid chromatography combined with Fourier transform ion cyclotron resonance mass spectrometry. Fifteen constituents from Baidianling Capsule were accurately identified by comparing the retention times with those of reference compounds, others were identified by comparing the retention times and mass spectrometry data, as well as retrieving the reference literature. This study provides a practical strategy for rapidly screening and identifying the multiple constituents of a complex traditional Chinese medicine. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Gas phase ion/molecule reactions as studied by Fourier Transform Ion Cyclotron Resonance mass spectrometry

    International Nuclear Information System (INIS)

    Joergensen, S.I.

    1985-01-01

    The subject of this thesis is gas phase ion/molecule reactions as studied by Fourier Transform Ion Cyclotron Resonance (FT-ICR) mass spectrometry (chapter 2 contains a short description of this method). Three chapters are mainly concerned with mechanistic aspects of gas phase ion/molecule reactions. An equally important aspect of the thesis is the stability and reactivity of α-thio carbanions, dipole stabilized carbanions and homoenolate anions, dealt with in the other four chapters. (Auth.)

  15. Matrix-assisted laser desorption fourier transform mass spectrometry for biological compounds

    Energy Technology Data Exchange (ETDEWEB)

    Hettich, R.; Buchanan, M.

    1990-01-01

    The recent development of matrix-assisted UV laser desorption (LD) mass spectrometry has made possible the ionization and detection of extremely large molecules (with molecular weights exceeding 100,000 Daltons). This technique has generated enormous interest in the biological community for the direct examination of large peptides and oligonucleotides. Although this matrix-assisted ionization method has been developed and used almost exclusively with time-of-flight (TOF) mass spectrometers, research is currently in progress to demonstrate this technique with trapped ion mass spectrometers, such as Fourier transform ion cyclotron resonance mass spectrometry (FTMS). The potential capabilities of FTMS for wide mass range, high resolution measurement, and ion trapping experiments suggest that this instrumental technique should be useful for the detailed structural characterization of large ions generated by the matrix-assisted technique. We have recently demonstrated that matrix-assisted ultraviolet laser desorption can be successfully used with FTMS for the ionization of small peptides. The objective of this report is to summarize the application and current limitations of matrix-assisted laser desorption FTMS for the characterization of peptides and oligonucleotides at the isomeric level. 4 refs., 3 figs., 2 tabs.

  16. Fourier transform NMR

    International Nuclear Information System (INIS)

    Hallenga, K.

    1991-01-01

    This paper discusses the concept of Fourier transformation one of the many precious legacies of the French mathematician Jean Baptiste Joseph Fourier, essential for understanding the link between continuous-wave (CW) and Fourier transform (FT) NMR. Although in modern FT NMR the methods used to obtain a frequency spectrum from the time-domain signal may vary greatly, from the efficient Cooley-Tukey algorithm to very elaborate iterative least-square methods based other maximum entropy method or on linear prediction, the principles for Fourier transformation are unchanged and give invaluable insight into the interconnection of many pairs of physical entities called Fourier pairs

  17. App. 1. Fourier series and Fourier transform

    International Nuclear Information System (INIS)

    Anon.

    1977-01-01

    Definitions, formulas and practical properties in quantum mechanics are presented: Fourier series (development of periodic function, Bessel-Parseval equality); Fourier transform (Parseval-Plancherel formula, Fourier transform in three-dimensional space) [fr

  18. Fourier transforms in spectroscopy

    CERN Document Server

    Kauppinen, Jyrki

    2000-01-01

    This modern approach to the subject is clearly and logically structured, and gives readers an understanding of the essence of Fourier transforms and their applications. All important aspects are included with respect to their use with optical spectroscopic data. Based on popular lectures, the authors provide the mathematical fundamentals and numerical applications which are essential in practical use. The main part of the book is dedicated to applications of FT in signal processing and spectroscopy, with IR and NIR, NMR and mass spectrometry dealt with both from a theoretical and practical poi

  19. Fourier transformation methods in the field of gamma spectrometry

    Indian Academy of Sciences (India)

    The basic principles of a new version of Fourier transformation is presented. This new version was applied to solve some main problems such as smoothing, and denoising in gamma spectroscopy. The mathematical procedures were first tested by simulated data and then by actual experimental data.

  20. Fractional finite Fourier transform.

    Science.gov (United States)

    Khare, Kedar; George, Nicholas

    2004-07-01

    We show that a fractional version of the finite Fourier transform may be defined by using prolate spheroidal wave functions of order zero. The transform is linear and additive in its index and asymptotically goes over to Namias's definition of the fractional Fourier transform. As a special case of this definition, it is shown that the finite Fourier transform may be inverted by using information over a finite range of frequencies in Fourier space, the inversion being sensitive to noise. Numerical illustrations for both forward (fractional) and inverse finite transforms are provided.

  1. Physicochemical properties determining the detection probability of tryptic peptides in Fourier transform mass spectrometry. A correlation study

    DEFF Research Database (Denmark)

    Nielsen, Michael L; Savitski, Mikhail M; Kjeldsen, Frank

    2004-01-01

    Sequence verification and mapping of posttranslational modifications require nearly 100% sequence coverage in the "bottom-up" protein analysis. Even in favorable cases, routine liquid chromatography-mass spectrometry detects from protein digests peptides covering 50-90% of the sequence. Here we...... investigated the reasons for limited peptide detection, considering various physicochemical aspects of peptide behavior in liquid chromatography-Fourier transform mass spectrometry (LC-FTMS). No overall correlation was found between the detection probability and peptide mass. In agreement with literature data...... between pI and signal response. An explanation of this paradoxal behavior was found through the observation that more acidic tryptic peptide lengths tend to be longer. Longer peptides tend to acquire higher average charge state in positive mode electrospray ionization than more basic but shorter...

  2. Generalized Fourier transforms classes

    DEFF Research Database (Denmark)

    Berntsen, Svend; Møller, Steen

    2002-01-01

    The Fourier class of integral transforms with kernels $B(\\omega r)$ has by definition inverse transforms with kernel $B(-\\omega r)$. The space of such transforms is explicitly constructed. A slightly more general class of generalized Fourier transforms are introduced. From the general theory...

  3. Fourier transforms principles and applications

    CERN Document Server

    Hansen, Eric W

    2014-01-01

    Fourier Transforms: Principles and Applications explains transform methods and their applications to electrical systems from circuits, antennas, and signal processors-ably guiding readers from vector space concepts through the Discrete Fourier Transform (DFT), Fourier series, and Fourier transform to other related transform methods.  Featuring chapter end summaries of key results, over two hundred examples and four hundred homework problems, and a Solutions Manual this book is perfect for graduate students in signal processing and communications as well as practicing engineers.

  4. Applications of Fourier Transform Ion Cyclotron Resonance (FT-ICR) and Orbitrap Based High Resolution Mass Spectrometry in Metabolomics and Lipidomics

    Science.gov (United States)

    Ghaste, Manoj; Mistrik, Robert; Shulaev, Vladimir

    2016-01-01

    Metabolomics, along with other “omics” approaches, is rapidly becoming one of the major approaches aimed at understanding the organization and dynamics of metabolic networks. Mass spectrometry is often a technique of choice for metabolomics studies due to its high sensitivity, reproducibility and wide dynamic range. High resolution mass spectrometry (HRMS) is a widely practiced technique in analytical and bioanalytical sciences. It offers exceptionally high resolution and the highest degree of structural confirmation. Many metabolomics studies have been conducted using HRMS over the past decade. In this review, we will explore the latest developments in Fourier transform mass spectrometry (FTMS) and Orbitrap based metabolomics technology, its advantages and drawbacks for using in metabolomics and lipidomics studies, and development of novel approaches for processing HRMS data. PMID:27231903

  5. Generalized Fourier transforms classes

    DEFF Research Database (Denmark)

    Berntsen, Svend; Møller, Steen

    2002-01-01

    The Fourier class of integral transforms with kernels $B(\\omega r)$ has by definition inverse transforms with kernel $B(-\\omega r)$. The space of such transforms is explicitly constructed. A slightly more general class of generalized Fourier transforms are introduced. From the general theory foll...... follows that integral transform with kernels which are products of a Bessel and a Hankel function or which is of a certain general hypergeometric type have inverse transforms of the same structure....

  6. Tunable fractional-order Fourier transformer

    International Nuclear Information System (INIS)

    Malyutin, A A

    2006-01-01

    A fractional two-dimensional Fourier transformer whose orders are tuned by means of optical quadrupoles is described. It is shown that in the optical scheme considered, the Fourier-transform order a element of [0,1] in one of the mutually orthogonal planes corresponds to the transform order (2-a) in another plane, i.e., to inversion and inverse Fourier transform of the order a. (laser modes and beams)

  7. Screening and confirmation criteria for hormone residue analysis using liquid chromatography accurate mass time-of-flight, Fourier transform ion cyclotron resonance and orbitrap mass spectrometry techniques

    NARCIS (Netherlands)

    Nielen, M.W.F.; Engelen, M.C. van; Zuiderent, R.; Ramaker, R.

    2007-01-01

    An emerging trend is recognised in hormone and veterinary drug residue analysis from liquid chromatography tandem mass spectrometry (LC/MS/MS) based screening and confirmation towards accurate mass alternatives such as LC coupled with time-of-flight (TOF), Fourier transform ion cyclotron resonance

  8. General Correlation Theorem for Trinion Fourier Transform

    OpenAIRE

    Bahri, Mawardi

    2017-01-01

    - The trinion Fourier transform is an extension of the Fourier transform in the trinion numbers setting. In this work we derive the correlation theorem for the trinion Fourier transform by using the relation between trinion convolution and correlation definitions in the trinion Fourier transform domains.

  9. Characterization of polyesters by matrix-assisted laser desorption/ionization and Fourier transform mass spectrometry.

    Science.gov (United States)

    Mize, Todd H; Simonsick, William J; Amster, I Jonathan

    2003-01-01

    Two homopolyesters, poly(neopentyl glycol-alt-isophthalic acid) and poly(hexanediol-alt-azelaic acid), and two copolyesters, poly(dipropoxylated bisphenol-A-alt-(isophthalic acid-co-adipic acid)) and poly(neopentyl glycol-alt-(adipic acid-co-isophthalic acid)) were analyzed by internal source matrix assisted laser desorption/ionization Fourier transform mass spectrometry (MALDI-FTMS). The high resolution and high mass accuracy provided by FTMS greatly facilitate the characterization of the polyester and copolyester samples. Isobaric resolution allows the ion abundances of overlapping isotopic envelopes to be assessed. Repeat units were confirmed and end functionality assigned. Single shot mass spectra of the entire polymeric distribution demonstrate that the dynamic range of this internal MALDI source instrument and the analyzer cell exceeds performance of those previously reported for higher field instruments. Corrections of space charge mass shift effects are demonstrated for the analytes using an external calibrant and (subsequent to confirmation of structure) via internal calibration which removes ambiguity due to space charge differences in calibrant and analyte spectra. Capillary gel permeation chromatography was used to prepare low polydispersity samples from a high polydispersity polyester, improving the measurement of molecular weight distribution two-fold while retaining the benefits of high resolution mass spectrometry for elucidation of oligomer identity.

  10. A Short Biography of Joseph Fourier and Historical Development of Fourier Series and Fourier Transforms

    Science.gov (United States)

    Debnath, Lokenath

    2012-01-01

    This article deals with a brief biographical sketch of Joseph Fourier, his first celebrated work on analytical theory of heat, his first great discovery of Fourier series and Fourier transforms. Included is a historical development of Fourier series and Fourier transforms with their properties, importance and applications. Special emphasis is made…

  11. The fractional Fourier transform and applications

    Science.gov (United States)

    Bailey, David H.; Swarztrauber, Paul N.

    1991-01-01

    This paper describes the 'fractional Fourier transform', which admits computation by an algorithm that has complexity proportional to the fast Fourier transform algorithm. Whereas the discrete Fourier transform (DFT) is based on integral roots of unity e exp -2(pi)i/n, the fractional Fourier transform is based on fractional roots of unity e exp -2(pi)i(alpha), where alpha is arbitrary. The fractional Fourier transform and the corresponding fast algorithm are useful for such applications as computing DFTs of sequences with prime lengths, computing DFTs of sparse sequences, analyzing sequences with noninteger periodicities, performing high-resolution trigonometric interpolation, detecting lines in noisy images, and detecting signals with linearly drifting frequencies. In many cases, the resulting algorithms are faster by arbitrarily large factors than conventional techniques.

  12. Fourier transforms in NMR, optical, and mass spectrometry

    International Nuclear Information System (INIS)

    Marshall, A.G.; Verdun, F.R.; Ohio State Univ., Columbus, OH

    1990-01-01

    This book is a teaching and reference text for Fourier transform methods as they are applied in spectroscopy. It offers a unified treatment of the three most popular types of FT/spectroscopy. Non-ideal effects are treated in detail: noise (source- and detector-limited); non-linear response; limits to spectrometer performance based on finite detection period, finite data size, mis-phasing, etc. Common puzzles and paradoxes are explained: e.g., use of mathematically complex variables to represent physically real quantities; interpretation of negative frequency signals; on-resonance versus off-resonance response; interpolation; ultimate accuracy of discrete representation of an analog signal; differences between linearly- and circularly-polarized radiation; multiplex advantage or disadvantage, etc. (author). refs.; figs.; tabs

  13. Bioconversion of red ginseng saponins in the gastro-intestinal tract in vitro model studied by high-performance liquid chromatography-high resolution Fourier transform ion cyclotron resonance mass spectrometry

    NARCIS (Netherlands)

    Kong, H.; Wang, M.; Venema, K.; Maathuis, A.; Heijden, R. van der; Greef, J. van der; Xu, G.; Hankemeier, T.

    2009-01-01

    A high-performance liquid chromatography-high resolution Fourier transform ion cyclotron resonance mass spectrometry (HPLC-FTICR-MS) method was developed to investigate the metabolism of ginsenosides in in vitro models of the gastro-intestinal tract. The metabolites were identified by

  14. Fourier transformation for engineering and natural science

    International Nuclear Information System (INIS)

    Klingen, B.

    2001-01-01

    The following topics are covered: functions, Dirac delta function, Fourier operators, Fourier integrals, Fourier transformation and periodic functions, discrete Fourier transformations and discrete filters, applications. (WL)

  15. Characterization of non-polar aromatic hydrocarbons in crude oil using atmospheric pressure laser ionization and Fourier transform ion cyclotron resonance mass spectrometry (APLI FT-ICR MS).

    Science.gov (United States)

    Schrader, Wolfgang; Panda, Saroj K; Brockmann, Klaus J; Benter, Thorsten

    2008-07-01

    We report on the successful application of the recently introduced atmospheric pressure laser ionization (APLI) method as a novel tool for the analysis of crude oil and its components. Using Fourier transform ion cyclotron resonance mass spectrometry, unambiguous determination of key compounds in this complex matrix with unprecedented sensitivity is presented.

  16. Fourier Transform Ion Cyclotron Resonance Mass Spectrometry at the Cyclotron Frequency.

    Science.gov (United States)

    Nagornov, Konstantin O; Kozhinov, Anton N; Tsybin, Yury O

    2017-04-01

    The phenomenon of ion cyclotron resonance allows for determining mass-to-charge ratio, m/z, of an ensemble of ions by means of measurements of their cyclotron frequency, ω c . In Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), the ω c quantity is usually unavailable for direct measurements: the resonant state is located close to the reduced cyclotron frequency (ω + ), whereas the ω c and the corresponding m/z values may be calculated via theoretical derivation from an experimental estimate of the ω + quantity. Here, we describe an experimental observation of a new resonant state, which is located close to the ω c frequency and is established because of azimuthally-dependent trapping electric fields of the recently developed ICR cells with narrow aperture detection electrodes. We show that in mass spectra, peaks close to ω + frequencies can be reduced to negligible levels relative to peaks close to ω c frequencies. Due to reduced errors with which the ω c quantity is obtained, the new resonance provides a means of cyclotron frequency measurements with precision greater than that achieved when ω + frequency peaks are employed. The described phenomenon may be considered for a development into an FT-ICR MS technology with increased mass accuracy for applications in basic research, life, and environmental sciences. Graphical Abstract ᅟ.

  17. A Unified Method of Finding Laplace Transforms, Fourier Transforms, and Fourier Series. [and] An Inversion Method for Laplace Transforms, Fourier Transforms, and Fourier Series. Integral Transforms and Series Expansions. Modules and Monographs in Undergraduate Mathematics and Its Applications Project. UMAP Units 324 and 325.

    Science.gov (United States)

    Grimm, C. A.

    This document contains two units that examine integral transforms and series expansions. In the first module, the user is expected to learn how to use the unified method presented to obtain Laplace transforms, Fourier transforms, complex Fourier series, real Fourier series, and half-range sine series for given piecewise continuous functions. In…

  18. On fractional Fourier transform moments

    NARCIS (Netherlands)

    Alieva, T.; Bastiaans, M.J.

    2000-01-01

    Based on the relation between the ambiguity function represented in a quasi-polar coordinate system and the fractional power spectra, the fractional Fourier transform moments are introduced. Important equalities for the global second-order fractional Fourier transform moments are derived and their

  19. Structural characterization of phospholipids by matrix-assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometry.

    Science.gov (United States)

    Marto, J A; White, F M; Seldomridge, S; Marshall, A G

    1995-11-01

    Matrix-assisted laser desorption/ionization (MALDI) Fourier transform ion cyclotron resonance mass spectrometry provides for structural analysis of the principal biological phospholipids: glycerophosphatidylcholine, -ethanolamine, -serine, and -inositol. Both positive and negative molecular or quasimolecular ions are generated in high abundance. Isolated molecular ions may be collisionally activated in the source side of a dual trap mass analyzer, yielding fragments serving to identify the polar head group (positive ion mode) and fatty acid side chains (negative ion mode). Azimuthal quadrupolar excitation following collisionally activated dissociation refocuses productions close to the solenoid axis; subsequent transfer of product ions to the analyzer ion trap allows for high-resolution mass analysis. Cyro-cooling of the sample probe with liquid nitrogen greatly reduces matrix adduction encountered in the negative ion mode.

  20. Electro-Optical Imaging Fourier-Transform Spectrometer

    Science.gov (United States)

    Chao, Tien-Hsin; Zhou, Hanying

    2006-01-01

    An electro-optical (E-O) imaging Fourier-transform spectrometer (IFTS), now under development, is a prototype of improved imaging spectrometers to be used for hyperspectral imaging, especially in the infrared spectral region. Unlike both imaging and non-imaging traditional Fourier-transform spectrometers, the E-O IFTS does not contain any moving parts. Elimination of the moving parts and the associated actuator mechanisms and supporting structures would increase reliability while enabling reductions in size and mass, relative to traditional Fourier-transform spectrometers that offer equivalent capabilities. Elimination of moving parts would also eliminate the vibrations caused by the motions of those parts. Figure 1 schematically depicts a traditional Fourier-transform spectrometer, wherein a critical time delay is varied by translating one the mirrors of a Michelson interferometer. The time-dependent optical output is a periodic representation of the input spectrum. Data characterizing the input spectrum are generated through fast-Fourier-transform (FFT) post-processing of the output in conjunction with the varying time delay.

  1. A new twist to fourier transforms

    CERN Document Server

    Meikle, Hamish D

    2004-01-01

    Making use of the inherent helix in the Fourier transform expression, this book illustrates both Fourier transforms and their properties in the round. The author draws on elementary complex algebra to manipulate the transforms, presenting the ideas in such a way as to avoid pages of complicated mathematics. Similarly, abbreviations are not used throughout and the language is kept deliberately clear so that the result is a text that is accessible to a much wider readership.The treatment is extended with the use of sampled data to finite and discrete transforms, the fast Fourier transform, or FFT, being a special case of a discrete transform. The application of Fourier transforms in statistics is illustrated for the first time using the examples operational research and later radar detection. In addition, a whole chapter on tapering or weighting functions is added for reference. The whole is rounded off by a glossary and examples of diagrams in three dimensions made possible by today's mathematics programs

  2. An optical Fourier transform coprocessor with direct phase determination.

    Science.gov (United States)

    Macfaden, Alexander J; Gordon, George S D; Wilkinson, Timothy D

    2017-10-20

    The Fourier transform is a ubiquitous mathematical operation which arises naturally in optics. We propose and demonstrate a practical method to optically evaluate a complex-to-complex discrete Fourier transform. By implementing the Fourier transform optically we can overcome the limiting O(nlogn) complexity of fast Fourier transform algorithms. Efficiently extracting the phase from the well-known optical Fourier transform is challenging. By appropriately decomposing the input and exploiting symmetries of the Fourier transform we are able to determine the phase directly from straightforward intensity measurements, creating an optical Fourier transform with O(n) apparent complexity. Performing larger optical Fourier transforms requires higher resolution spatial light modulators, but the execution time remains unchanged. This method could unlock the potential of the optical Fourier transform to permit 2D complex-to-complex discrete Fourier transforms with a performance that is currently untenable, with applications across information processing and computational physics.

  3. Applications of Fourier transforms to generalized functions

    CERN Document Server

    Rahman, M

    2011-01-01

    This book explains how Fourier transforms can be applied to generalized functions. The generalized function is one of the important branches of mathematics and is applicable in many practical fields. Its applications to the theory of distribution and signal processing are especially important. The Fourier transform is a mathematical procedure that can be thought of as transforming a function from its time domain to the frequency domain.The book contains six chapters and three appendices. Chapter 1 deals with preliminary remarks on Fourier series from a general point of view and also contains an introduction to the first generalized function. Chapter 2 is concerned with the generalized functions and their Fourier transforms. Chapter 3 contains the Fourier transforms of particular generalized functions. The author has stated and proved 18 formulas dealing with the Fourier transforms of generalized functions, and demonstrated some important problems of practical interest. Chapter 4 deals with the asymptotic esti...

  4. Implementation of quantum and classical discrete fractional Fourier transforms

    Science.gov (United States)

    Weimann, Steffen; Perez-Leija, Armando; Lebugle, Maxime; Keil, Robert; Tichy, Malte; Gräfe, Markus; Heilmann, René; Nolte, Stefan; Moya-Cessa, Hector; Weihs, Gregor; Christodoulides, Demetrios N.; Szameit, Alexander

    2016-01-01

    Fourier transforms, integer and fractional, are ubiquitous mathematical tools in basic and applied science. Certainly, since the ordinary Fourier transform is merely a particular case of a continuous set of fractional Fourier domains, every property and application of the ordinary Fourier transform becomes a special case of the fractional Fourier transform. Despite the great practical importance of the discrete Fourier transform, implementation of fractional orders of the corresponding discrete operation has been elusive. Here we report classical and quantum optical realizations of the discrete fractional Fourier transform. In the context of classical optics, we implement discrete fractional Fourier transforms of exemplary wave functions and experimentally demonstrate the shift theorem. Moreover, we apply this approach in the quantum realm to Fourier transform separable and path-entangled biphoton wave functions. The proposed approach is versatile and could find applications in various fields where Fourier transforms are essential tools. PMID:27006089

  5. Implementation of quantum and classical discrete fractional Fourier transforms.

    Science.gov (United States)

    Weimann, Steffen; Perez-Leija, Armando; Lebugle, Maxime; Keil, Robert; Tichy, Malte; Gräfe, Markus; Heilmann, René; Nolte, Stefan; Moya-Cessa, Hector; Weihs, Gregor; Christodoulides, Demetrios N; Szameit, Alexander

    2016-03-23

    Fourier transforms, integer and fractional, are ubiquitous mathematical tools in basic and applied science. Certainly, since the ordinary Fourier transform is merely a particular case of a continuous set of fractional Fourier domains, every property and application of the ordinary Fourier transform becomes a special case of the fractional Fourier transform. Despite the great practical importance of the discrete Fourier transform, implementation of fractional orders of the corresponding discrete operation has been elusive. Here we report classical and quantum optical realizations of the discrete fractional Fourier transform. In the context of classical optics, we implement discrete fractional Fourier transforms of exemplary wave functions and experimentally demonstrate the shift theorem. Moreover, we apply this approach in the quantum realm to Fourier transform separable and path-entangled biphoton wave functions. The proposed approach is versatile and could find applications in various fields where Fourier transforms are essential tools.

  6. Investigation of the metabolism of ergot alkaloids in cell culture by fourier transformation mass spectrometry.

    Science.gov (United States)

    Mulac, Dennis; Grote, Anna-Karina; Kleigrewe, Karin; Humpf, Hans-Ulrich

    2011-07-27

    Ergot alkaloids are known toxic secondary metabolites of the fungus Claviceps purpurea occurring in various grains, especially rye products. The liver is responsible for converting the ergot alkaloids into metabolites; however, the toxic impact of these end products of metabolism is still unknown. The aim of this study was to analyze the metabolism of ergot alkaloids in colon and liver cell lines (HT-29, HepG2), as well as in human primary renal cells (RPTEC). It was shown that cells in vitro are able to metabolize ergot alkaloids, forming a variety of metabolic compounds. Significant differences between the used cell types could be identified, and a suitable model system was established using HT-29 cells, performing an intensive metabolism to hydroxylated metabolites. The formed substances were analyzed by coupling of high-performance liquid chromatography with fluorescence detection and Fourier transformation mass spectrometry (HPLC-FLD-FTMS) as a powerful tool to identify known and unknown metabolites.

  7. Application of Fourier-transform ion cyclotron resonance mass spectrometry to metabolic profiling and metabolite identification.

    Science.gov (United States)

    Ohta, Daisaku; Kanaya, Shigehiko; Suzuki, Hideyuki

    2010-02-01

    Metabolomics, as an essential part of genomics studies, intends holistic understanding of metabolic networks through simultaneous analysis of a myriad of both known and unknown metabolites occurring in living organisms. The initial stage of metabolomics was designed for the reproducible analyses of known metabolites based on their comparison to available authentic compounds. Such metabolomics platforms were mostly based on mass spectrometry (MS) technologies enabled by a combination of different ionization methods together with a variety of separation steps including LC, GC, and CE. Among these, Fourier-transform ion cyclotron resonance MS (FT-ICR/MS) is distinguished from other MS technologies by its ultrahigh resolution power in mass to charge ratio (m/z). The potential of FT-ICR/MS as a distinctive metabolomics tool has been demonstrated in nontargeted metabolic profiling and functional characterization of novel genes. Here, we discuss both the advantages and difficulties encountered in the FT-ICR/MS metabolomics studies.

  8. Alternating multivariate trigonometric functions and corresponding Fourier transforms

    International Nuclear Information System (INIS)

    Klimyk, A U; Patera, J

    2008-01-01

    We define and study multivariate sine and cosine functions, symmetric with respect to the alternating group A n , which is a subgroup of the permutation (symmetric) group S n . These functions are eigenfunctions of the Laplace operator. They determine Fourier-type transforms. There exist three types of such transforms: expansions into corresponding sine-Fourier and cosine-Fourier series, integral sine-Fourier and cosine-Fourier transforms, and multivariate finite sine and cosine transforms. In all these transforms, alternating multivariate sine and cosine functions are used as a kernel

  9. Properties of the distributional finite Fourier transform

    OpenAIRE

    Carmichael, Richard D.

    2016-01-01

    The analytic functions in tubes which obtain the distributional finite Fourier transform as boundary value are shown to have a strong boundedness property and to be recoverable as a Fourier-Laplace transform, a distributional finite Fourier transform, and as a Cauchy integral of a distribution associated with the boundary value.

  10. Fourier transform nuclear magnetic resonance

    International Nuclear Information System (INIS)

    Geick, R.

    1981-01-01

    This review starts with the basic principles of resonance phenomena in physical systems. Especially, the connection is shown between the properties of these systems and Fourier transforms. Next, we discuss the principles of nuclear magnetic resonance. Starting from the general properties of physical systems showing resonance phenomena and from the special properties of nuclear spin systems, the main part of this paper reviews pulse and Fourier methods in nuclear magnetic resonance. Among pulse methods, an introduction will be given to spin echoes, and, apart from the principle of Fourier transform nuclear magnetic resonance, an introduction to the technical problems of this method, e.g. resolution in the frequency domain, aliasing, phase and intensity errors, stationary state of the spin systems for repetitive measurements, proton decoupling, and application of Fourier methods to systems in a nonequilibrium state. The last section is devoted to special applications of Fourier methods and recent developments, e.g. measurement of relaxation times, solvent peak suppression, 'rapid scan'-method, methods for suppressing the effects of dipolar coupling in solids, two-dimensional Fourier transform nuclear magnetic resonance, and spin mapping or zeugmatography. (author)

  11. Wigner distribution and fractional Fourier transform

    NARCIS (Netherlands)

    Alieva, T.; Bastiaans, M.J.; Boashash, B.

    2003-01-01

    We have described the relationship between the fractional Fourier transform and the Wigner distribution by using the Radon-Wigner transform, which is a set of projections of the Wigner distribution as well as a set of squared moduli of the fractional Fourier transform. We have introduced the concept

  12. Automatic Fourier transform and self-Fourier beams due to parabolic potential

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yiqi, E-mail: zhangyiqi@mail.xjtu.edu.cn [Key Laboratory for Physical Electronics and Devices of the Ministry of Education & Shaanxi Key Lab of Information Photonic Technique, Xi’an Jiaotong University, Xi’an 710049 (China); Liu, Xing [Key Laboratory for Physical Electronics and Devices of the Ministry of Education & Shaanxi Key Lab of Information Photonic Technique, Xi’an Jiaotong University, Xi’an 710049 (China); Belić, Milivoj R., E-mail: milivoj.belic@qatar.tamu.edu [Science Program, Texas A& M University at Qatar, P.O. Box 23874 Doha (Qatar); Zhong, Weiping [Department of Electronic and Information Engineering, Shunde Polytechnic, Shunde 528300 (China); Petrović, Milan S. [Institute of Physics, P.O. Box 68, 11001 Belgrade (Serbia); Zhang, Yanpeng, E-mail: ypzhang@mail.xjtu.edu.cn [Key Laboratory for Physical Electronics and Devices of the Ministry of Education & Shaanxi Key Lab of Information Photonic Technique, Xi’an Jiaotong University, Xi’an 710049 (China)

    2015-12-15

    We investigate the propagation of light beams including Hermite–Gauss, Bessel–Gauss and finite energy Airy beams in a linear medium with parabolic potential. Expectedly, the beams undergo oscillation during propagation, but quite unexpectedly they also perform automatic Fourier transform, that is, periodic change from the beam to its Fourier transform and back. In addition to oscillation, the finite-energy Airy beams exhibit periodic inversion during propagation. The oscillating period of parity-asymmetric beams is twice that of the parity-symmetric beams. Based on the propagation in parabolic potential, we introduce a class of optically-interesting beams that are self-Fourier beams—that is, the beams whose Fourier transforms are the beams themselves.

  13. Group-invariant finite Fourier transforms

    International Nuclear Information System (INIS)

    Shenefelt, M.H.

    1988-01-01

    The computation of the finite Fourier transform of functions is one of the most used computations in crystallography. Since the Fourier transform involved in 3-dimensional, the size of the computation becomes very large even for relatively few sample points along each edge. In this thesis, there is a family of algorithms that reduce the computation of Fourier transform of functions respecting the symmetries. Some properties of these algorithms are: (1) The algorithms make full use of the group of symmetries of a crystal. (2) The algorithms can be factored and combined according to the prime factorization of the number of points in the sample space. (3) The algorithms are organized into a family using the group structure of the crystallographic groups to make iterative procedures possible

  14. Collision-induced dissociation with Fourier transform mass spectrometry

    International Nuclear Information System (INIS)

    Cody, R.B.; Burnier, R.C.; Freiser, B.S.

    1982-01-01

    Collision-induced dissociations (CID) is demonstrated on a number of primary and secondary ions using a Nicolet prototype Fourier transform mass spectrometer (FT-MS). Like the triple quadrupole technique, CID using FT-MS is a relatively low energy and efficient process. The ability to study a wide range of ion-molecule reaction products is exemplified by results on proton-bound dimers and transition metal containing ionic species. Variation of collision energy by varying the RF irradiation level can provide information about product distributions as a function of energy as well as yield ion structural information. Like the triple quadrupole technique, no slits are employed and virtually all of the fragment ions formed by the CID process may be detected. Unlike all previous mass spectrometric techniques for studying CID, a tandem instrument is not required, and different experiments are performed by making software modifications rather than hardware modifications

  15. On the inverse windowed Fourier transform

    OpenAIRE

    Rebollo Neira, Laura; Fernández Rubio, Juan Antonio

    1999-01-01

    The inversion problem concerning the windowed Fourier transform is considered. It is shown that, out of the infinite solutions that the problem admits, the windowed Fourier transform is the "optimal" solution according to a maximum-entropy selection criterion. Peer Reviewed

  16. (Anti)symmetric multivariate exponential functions and corresponding Fourier transforms

    International Nuclear Information System (INIS)

    Klimyk, A U; Patera, J

    2007-01-01

    We define and study symmetrized and antisymmetrized multivariate exponential functions. They are defined as determinants and antideterminants of matrices whose entries are exponential functions of one variable. These functions are eigenfunctions of the Laplace operator on the corresponding fundamental domains satisfying certain boundary conditions. To symmetric and antisymmetric multivariate exponential functions there correspond Fourier transforms. There are three types of such Fourier transforms: expansions into the corresponding Fourier series, integral Fourier transforms and multivariate finite Fourier transforms. Eigenfunctions of the integral Fourier transforms are found

  17. Fourier transform ion cyclotron resonance mass spectrometry: the analytical tool for heavy oil and bitumen characterization

    Energy Technology Data Exchange (ETDEWEB)

    Oldenburg, Thomas B.P; Brown, Melisa; Hsieh, Ben; Larter, Steve [Petroleum Reservoir Group (prg), Department of Geoscience, University of Calgary, Alberta (Canada)

    2011-07-01

    The Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FTICRMS), developed in the 1970's by Marshall and Comisarow at the University of British Columbia, has become a commercially available tool capable of analyzing several hundred thousand components in a petroleum mixture at once. This analytical technology will probably usher a dramatic revolution in geochemical capability, equal to or greater than the molecular revolution that occurred when GCMS technologies became cheaply available. The molecular resolution and information content given by the FTICRMS petroleum analysis can be compared to the information in the human genome. With current GCMS-based petroleum geochemical protocols perhaps a few hundred components can be quantitatively determined, but with FTICRMS, 1000 times this number of components could possibly be resolved. However, fluid and other properties depend on interaction of this multitude of hydrocarbon and non-hydrocarbon components, not the components themselves, and access to the full potential of this new petroleomics will depend on the definition of this interactome.

  18. Dioxin analysis by gas chromatography-Fourier transform ion cyclotron resonance mass spectrometry (GC-FTICRMS).

    Science.gov (United States)

    Taguchi, Vince Y; Nieckarz, Robert J; Clement, Ray E; Krolik, Stefan; Williams, Robert

    2010-11-01

    The feasibility of utilizing a gas chromatograph-tandem quadrupole-Fourier transform ion cyclotron resonance mass spectrometer (GC-MS/MS-FTICRMS) to analyze chlorinated-dioxins/furans (CDDs/CDFs) and mixed halogenated dioxins/furans (HDDs/HDFs) was investigated by operating the system in the GC-FTICRMS mode. CDDs/CDFs and mixed HDDs/HDFs could be analyzed at 50,000 to 100,000 resolving power (RP) on the capillary gas chromatographic time scale. Initial experiments demonstrated that 1 pg of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and 5 pg of 2-bromo-3,7,8-trichlorodibenzo-p-dioxin (BTrCDD) could be detected. The feasibility of utilizing an FTICRMS for screening of CDDs/CDFs, HDDs/HDFs and related compounds was also investigated by analyzing an extract from vegetation exposed to fall-out from an industrial fire. CDDs/CDFs, chlorinated pyrenes and chlorinated tetracenes could be detected from a Kendrick plot analysis of the ultrahigh resolution mass spectra. Mass accuracies were of the order of 0.5 ppm on standards with external mass calibration and 1 ppm on a sample with internal mass calibration. Copyright © 2010 American Society for Mass Spectrometry. Published by Elsevier Inc. All rights reserved.

  19. Advances in data processing for open-path Fourier transform infrared spectrometry of greenhouse gases.

    Science.gov (United States)

    Shao, Limin; Griffiths, Peter R; Leytem, April B

    2010-10-01

    The automated quantification of three greenhouse gases, ammonia, methane, and nitrous oxide, in the vicinity of a large dairy farm by open-path Fourier transform infrared (OP/FT-IR) spectrometry at intervals of 5 min is demonstrated. Spectral pretreatment, including the automated detection and correction of the effect of interrupting the infrared beam, is by a moving object, and the automated correction for the nonlinear detector response is applied to the measured interferograms. Two ways of obtaining quantitative data from OP/FT-IR data are described. The first, which is installed in a recently acquired commercial OP/FT-IR spectrometer, is based on classical least-squares (CLS) regression, and the second is based on partial least-squares (PLS) regression. It is shown that CLS regression only gives accurate results if the absorption features of the analytes are located in very short spectral intervals where lines due to atmospheric water vapor are absent or very weak; of the three analytes examined, only ammonia fell into this category. On the other hand, PLS regression works allowed what appeared to be accurate results to be obtained for all three analytes.

  20. On the windowed Fourier transform as an interpolation of the Gabor transform

    NARCIS (Netherlands)

    Bastiaans, M.J.; Prochßzka, A.; Uhlør, J.; Sovka, P.

    1997-01-01

    The windowed Fourier transform and its sampled version - the Gabor transform - are introduced. With the help of Gabor's signal expansion, an interpolation function is derived with which the windowed Fourier transform can be constructed from the Gabor transform. Using the Zak transform, it is shown

  1. Time-of-flight Fourier spectrometry of UCN

    International Nuclear Information System (INIS)

    Kulin, G.V.; Frank, A.I.; Goryunov, S.V.; Kustov, D.V.; Geltenbort, P.; Jentshel, M.; Strepetov, A.N.; Bushuev, V.A.

    2014-01-01

    The results of preliminary experiments on TOF Fourier UCN spectrometry are presented. The description of the new Fourier spectrometer that may be used for the measurement of the UCN spectra arising from diffraction by a moving grating is given. The results of preliminary experiments and Monte Carlo calculations give reason to hope for the success of the planned experiment.

  2. Surface Fourier-transform lens using a metasurface

    International Nuclear Information System (INIS)

    Li, Yun Bo; Cai, Ben Geng; Cheng, Qiang; Cui, Tie Jun

    2015-01-01

    We propose a surface (or 2D) Fourier-transform lens using a gradient refractive index (GRIN) metasurface in the microwave band, which is composed of sub-wavelength quasi-periodical metallic patches on a grounded dielectric substrate. Such a metasurface supports the transverse magnetic (TM) modes of surface waves. To gradually change the size of textures, we obtain different surface refractive indices, which can be tailored to fit the required refractive-index profile of a surface Fourier-transform lens. According to the theory of spatial Fourier transformation, we make use of the proposed lens to realize surface plane-wave scanning under different feeding locations. The simulation and experimental results jointly confirm the validity of the surface Fourier-transform lens. The proposed method can also be extended to the terahertz frequency. (paper)

  3. Identification of new natural sweet compounds in wine using centrifugal partition chromatography-gustatometry and Fourier transform mass spectrometry.

    Science.gov (United States)

    Marchal, Axel; Waffo-Téguo, Pierre; Génin, Eric; Mérillon, Jean-Michel; Dubourdieu, Denis

    2011-12-15

    Sweetness contributes notably to the taste-balance of dry wines and increases during oak-barrel aging owing to the release of natural sweeteners from wood. The search for such taste-active molecules, which are sometimes present at very low concentrations in wine or other complex matrixes, requires both reliable purification tools and powerful identification techniques. Here, we report the development of an original inductive method using centrifugal partition chromatography (CPC) and sensorial analysis. This method, called CPC-gustatometry, was implemented to isolate a sweet fraction with only four compounds from a complex oak wood extract. The recently developed Fourier transform mass spectrometry (FT-MS, Orbitrap analyzer) was used jointly with two-dimensional nuclear magnetic resonance (2D (1)H and (13)C NMR) to obtain the structural elucidation of the purified compounds. The tandem mass spectrometry (MS/MS) spectra obtained with resonant and nonresonant fragmentation modes were compared, thus providing complementary information about the molecular structure. Two oleanane-type triterpenoids substituted with galloyl and glucosyl moieties were identified, one of which exhibits sweet properties. We term these compounds which have never been reported, Quercotriterpenoside I and II.

  4. Fourier Transform Mass Spectrometry and Nuclear Magnetic Resonance Analysis for the Rapid and Accurate Characterization of Hexacosanoylceramide.

    Science.gov (United States)

    Ross, Charles W; Simonsick, William J; Bogusky, Michael J; Celikay, Recep W; Guare, James P; Newton, Randall C

    2016-06-28

    Ceramides are a central unit of all sphingolipids which have been identified as sites of biological recognition on cellular membranes mediating cell growth and differentiation. Several glycosphingolipids have been isolated, displaying immunomodulatory and anti-tumor activities. These molecules have generated considerable interest as potential vaccine adjuvants in humans. Accurate analyses of these and related sphingosine analogues are important for the characterization of structure, biological function, and metabolism. We report the complementary use of direct laser desorption ionization (DLDI), sheath flow electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) and high-field nuclear magnetic resonance (NMR) analysis for the rapid, accurate identification of hexacosanoylceramide and starting materials. DLDI does not require stringent sample preparation and yields representative ions. Sheath-flow ESI yields ions of the product and byproducts and was significantly better than monospray ESI due to improved compound solubility. Negative ion sheath flow ESI provided data of starting materials and products all in one acquisition as hexacosanoic acid does not ionize efficiently when ceramides are present. NMR provided characterization of these lipid molecules complementing the results obtained from MS analyses. NMR data was able to differentiate straight chain versus branched chain alkyl groups not easily obtained from mass spectrometry.

  5. Fourier Transform Mass Spectrometry and Nuclear Magnetic Resonance Analysis for the Rapid and Accurate Characterization of Hexacosanoylceramide

    Directory of Open Access Journals (Sweden)

    Charles W. Ross

    2016-06-01

    Full Text Available Ceramides are a central unit of all sphingolipids which have been identified as sites of biological recognition on cellular membranes mediating cell growth and differentiation. Several glycosphingolipids have been isolated, displaying immunomodulatory and anti-tumor activities. These molecules have generated considerable interest as potential vaccine adjuvants in humans. Accurate analyses of these and related sphingosine analogues are important for the characterization of structure, biological function, and metabolism. We report the complementary use of direct laser desorption ionization (DLDI, sheath flow electrospray ionization (ESI Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS and high-field nuclear magnetic resonance (NMR analysis for the rapid, accurate identification of hexacosanoylceramide and starting materials. DLDI does not require stringent sample preparation and yields representative ions. Sheath-flow ESI yields ions of the product and byproducts and was significantly better than monospray ESI due to improved compound solubility. Negative ion sheath flow ESI provided data of starting materials and products all in one acquisition as hexacosanoic acid does not ionize efficiently when ceramides are present. NMR provided characterization of these lipid molecules complementing the results obtained from MS analyses. NMR data was able to differentiate straight chain versus branched chain alkyl groups not easily obtained from mass spectrometry.

  6. Fourier transforms in radar and signal processing

    CERN Document Server

    Brandwood, David

    2011-01-01

    Fourier transforms are used widely, and are of particular value in the analysis of single functions and combinations of functions found in radar and signal processing. Still, many problems that could have been tackled by using Fourier transforms may have gone unsolved because they require integration that is difficult and tedious. This newly revised and expanded edition of a classic Artech House book provides you with an up-to-date, coordinated system for performing Fourier transforms on a wide variety of functions. Along numerous updates throughout the book, the Second Edition includes a crit

  7. Quantum arithmetic with the Quantum Fourier Transform

    OpenAIRE

    Ruiz-Perez, Lidia; Garcia-Escartin, Juan Carlos

    2014-01-01

    The Quantum Fourier Transform offers an interesting way to perform arithmetic operations on a quantum computer. We review existing Quantum Fourier Transform adders and multipliers and propose some modifications that extend their capabilities. Among the new circuits, we propose a quantum method to compute the weighted average of a series of inputs in the transform domain.

  8. Clifford Fourier transform on vector fields.

    Science.gov (United States)

    Ebling, Julia; Scheuermann, Gerik

    2005-01-01

    Image processing and computer vision have robust methods for feature extraction and the computation of derivatives of scalar fields. Furthermore, interpolation and the effects of applying a filter can be analyzed in detail and can be advantages when applying these methods to vector fields to obtain a solid theoretical basis for feature extraction. We recently introduced the Clifford convolution, which is an extension of the classical convolution on scalar fields and provides a unified notation for the convolution of scalar and vector fields. It has attractive geometric properties that allow pattern matching on vector fields. In image processing, the convolution and the Fourier transform operators are closely related by the convolution theorem and, in this paper, we extend the Fourier transform to include general elements of Clifford Algebra, called multivectors, including scalars and vectors. The resulting convolution and derivative theorems are extensions of those for convolution and the Fourier transform on scalar fields. The Clifford Fourier transform allows a frequency analysis of vector fields and the behavior of vector-valued filters. In frequency space, vectors are transformed into general multivectors of the Clifford Algebra. Many basic vector-valued patterns, such as source, sink, saddle points, and potential vortices, can be described by a few multivectors in frequency space.

  9. q-Generalization of the inverse Fourier transform

    International Nuclear Information System (INIS)

    Jauregui, M.; Tsallis, C.

    2011-01-01

    A wide class of physical distributions appears to follow the q-Gaussian form, which plays the role of attractor according to a q-generalized Central Limit Theorem, where a q-generalized Fourier transform plays an important role. We introduce here a method which determines a distribution from the knowledge of its q-Fourier transform and some supplementary information. This procedure involves a recently q-generalized representation of the Dirac delta and the class of functions on which it acts. The present method conveniently extends the inverse of the standard Fourier transform, and is therefore expected to be very useful in the study of many complex systems. - Highlights: → We present a method to invert the q-Fourier transform of a distribution. → We illustrate when Dirac delta can be represented using q-exponentials. → We describe a family of functions for which this new representation works.

  10. Technology of the Gramophone Records of the Music Museum by Fourier Transform Infrared Spectrometry (FTIR Method

    Directory of Open Access Journals (Sweden)

    Seyedeh Zeinab Afzali

    2017-02-01

    Full Text Available Music is one of the branches of the art whose helpful role and usefulness in the human’s mind and soul is undeniable. It is the only art which in the philosophers’ divisions is directly linked with the human spirit and immediate overflows the ears of his soul. The sound, as a psychological phenomenon is associated with the emotion and excitement so that sometimes calms and sometimes confuses the human. This study aims to examine the technology of the gramophone records in the Music Museum by Fourier transform infrared spectrometry (FTIR. The method of this research is experimental and the data are collected by documentation, library, and using FTIR tests. Some records of the Music Museum were studied including four samples of 78 rpm platter (stone platter, one sample of 45 rpm, and one sample of 33 rpm (vinyl platter. The results of the FTIR test indicated that the materials of the records were vinyl and shellac and in their raw material, some of the softening additives (phthalates and fillers (silica and calcium carbonate compounds had been used.

  11. The Role of Ultrahigh Resolution Fourier Transform Mass Spectrometry (FT-MS) in Astrobiology-Related Research: Analysis of Meteorites and Tholins.

    Science.gov (United States)

    Somogyi, Árpád; Thissen, Roland; Orthous-Daunay, Francois-Régis; Vuitton, Véronique

    2016-03-24

    It is an important but also a challenging analytical problem to understand the chemical composition and structure of prebiotic organic matter that is present in extraterrestrial materials. Its formation, evolution and content in the building blocks ("seeds") for more complex molecules, such as proteins and DNA, are key questions in the field of exobiology. Ultrahigh resolution mass spectrometry is one of the best analytical techniques that can be applied because it provides reliable information on the chemical composition and structure of individual components of complex organic mixtures. Prebiotic organic material is delivered to Earth by meteorites or generated in laboratories in simulation (model) experiments that mimic space or atmospheric conditions. Recent representative examples for ultrahigh resolution mass spectrometry studies using Fourier-transform (FT) mass spectrometers such as Orbitrap and ion cyclotron resonance (ICR) mass spectrometers are shown and discussed in the present article, including: (i) the analysis of organic matter of meteorites; (ii) modeling atmospheric processes in ICR cells; and (iii) the structural analysis of laboratory made tholins that might be present in the atmosphere and surface of Saturn's largest moon, Titan.

  12. Angular acceptance analysis of an infrared focal plane array with a built-in stationary Fourier transform spectrometer.

    Science.gov (United States)

    Gillard, Frédéric; Ferrec, Yann; Guérineau, Nicolas; Rommeluère, Sylvain; Taboury, Jean; Chavel, Pierre

    2012-06-01

    Stationary Fourier transform spectrometry is an interesting concept for building reliable field or embedded spectroradiometers, especially for the mid- and far- IR. Here, a very compact configuration of a cryogenic stationary Fourier transform IR (FTIR) spectrometer is investigated, where the interferometer is directly integrated in the focal plane array (FPA). We present a theoretical analysis to explain and describe the fringe formation inside the FTIR-FPA structure when illuminated by an extended source positioned at a finite distance from the detection plane. The results are then exploited to propose a simple front lens design compatible with a handheld package.

  13. Rainbow Fourier Transform

    Science.gov (United States)

    Alexandrov, Mikhail D.; Cairns, Brian; Mishchenko, Michael I.

    2012-01-01

    We present a novel technique for remote sensing of cloud droplet size distributions. Polarized reflectances in the scattering angle range between 135deg and 165deg exhibit a sharply defined rainbow structure, the shape of which is determined mostly by single scattering properties of cloud particles, and therefore, can be modeled using the Mie theory. Fitting the observed rainbow with such a model (computed for a parameterized family of particle size distributions) has been used for cloud droplet size retrievals. We discovered that the relationship between the rainbow structures and the corresponding particle size distributions is deeper than it had been commonly understood. In fact, the Mie theory-derived polarized reflectance as a function of reduced scattering angle (in the rainbow angular range) and the (monodisperse) particle radius appears to be a proxy to a kernel of an integral transform (similar to the sine Fourier transform on the positive semi-axis). This approach, called the rainbow Fourier transform (RFT), allows us to accurately retrieve the shape of the droplet size distribution by the application of the corresponding inverse transform to the observed polarized rainbow. While the basis functions of the proxy-transform are not exactly orthogonal in the finite angular range, this procedure needs to be complemented by a simple regression technique, which removes the retrieval artifacts. This non-parametric approach does not require any a priori knowledge of the droplet size distribution functional shape and is computationally fast (no look-up tables, no fitting, computations are the same as for the forward modeling).

  14. Fourier series, Fourier transform and their applications to mathematical physics

    CERN Document Server

    Serov, Valery

    2017-01-01

    This text serves as an introduction to the modern theory of analysis and differential equations with applications in mathematical physics and engineering sciences.  Having outgrown from a series of half-semester courses given at University of Oulu, this book consists of four self-contained parts. The first part, Fourier Series and the Discrete Fourier Transform, is devoted to the classical one-dimensional trigonometric Fourier series with some applications to PDEs and signal processing.  The second part, Fourier Transform and Distributions, is concerned with distribution theory of L. Schwartz and its applications to the Schrödinger and magnetic Schrödinger operations.  The third part, Operator Theory and Integral Equations, is devoted mostly to the self-adjoint but unbounded operators in Hilbert spaces and their applications to integral equations in such spaces. The fourth and final part, Introduction to Partial Differential Equations, serves as an introduction to modern methods for classical theory o...

  15. Fourier transform and its application to 1D and 2D NMR

    International Nuclear Information System (INIS)

    Canet, D.

    1988-01-01

    In this review article, the following points are developed: Pulsed NMR and Fourier transform; Fourier transform and two-dimensional spectroscopy; Mathematical properties of Fourier transform; Fourier transform of a sine function- one dimensional NMR; Fourier transform of a product of sine functions - two-dimensional NMR; Data manipulations in the time domain; Numerical Fourier transform [fr

  16. Replica Fourier Transform: Properties and applications

    International Nuclear Information System (INIS)

    Crisanti, A.; De Dominicis, C.

    2015-01-01

    The Replica Fourier Transform is the generalization of the discrete Fourier Transform to quantities defined on an ultrametric tree. It finds use in conjunction of the replica method used to study thermodynamics properties of disordered systems such as spin glasses. Its definition is presented in a systematic and simple form and its use illustrated with some representative examples. In particular we give a detailed discussion of the diagonalization in the Replica Fourier Space of the Hessian matrix of the Gaussian fluctuations about the mean field saddle point of spin glass theory. The general results are finally discussed for a generic spherical spin glass model, where the Hessian can be computed analytically

  17. The morphing of geographical features by Fourier transformation.

    Science.gov (United States)

    Li, Jingzhong; Liu, Pengcheng; Yu, Wenhao; Cheng, Xiaoqiang

    2018-01-01

    This paper presents a morphing model of vector geographical data based on Fourier transformation. This model involves three main steps. They are conversion from vector data to Fourier series, generation of intermediate function by combination of the two Fourier series concerning a large scale and a small scale, and reverse conversion from combination function to vector data. By mirror processing, the model can also be used for morphing of linear features. Experimental results show that this method is sensitive to scale variations and it can be used for vector map features' continuous scale transformation. The efficiency of this model is linearly related to the point number of shape boundary and the interceptive value n of Fourier expansion. The effect of morphing by Fourier transformation is plausible and the efficiency of the algorithm is acceptable.

  18. Hyperspectral imaging using the single-pixel Fourier transform technique

    Science.gov (United States)

    Jin, Senlin; Hui, Wangwei; Wang, Yunlong; Huang, Kaicheng; Shi, Qiushuai; Ying, Cuifeng; Liu, Dongqi; Ye, Qing; Zhou, Wenyuan; Tian, Jianguo

    2017-03-01

    Hyperspectral imaging technology is playing an increasingly important role in the fields of food analysis, medicine and biotechnology. To improve the speed of operation and increase the light throughput in a compact equipment structure, a Fourier transform hyperspectral imaging system based on a single-pixel technique is proposed in this study. Compared with current imaging spectrometry approaches, the proposed system has a wider spectral range (400-1100 nm), a better spectral resolution (1 nm) and requires fewer measurement data (a sample rate of 6.25%). The performance of this system was verified by its application to the non-destructive testing of potatoes.

  19. Fast inverse nonlinear Fourier transformation using exponential one-step methods : Darboux transformation

    NARCIS (Netherlands)

    Vaibhav, V.K.

    2017-01-01

    This paper considers the non-Hermitian Zakharov-Shabat (ZS) scattering problem which forms the basis for defining the SU(2) nonlinear Fourier transformation (NFT). The theoretical underpinnings of this generalization of the conventional Fourier transformation are quite well established in the

  20. High-Throughput Screening Using Fourier-Transform Infrared Imaging

    Directory of Open Access Journals (Sweden)

    Erdem Sasmaz

    2015-06-01

    Full Text Available Efficient parallel screening of combinatorial libraries is one of the most challenging aspects of the high-throughput (HT heterogeneous catalysis workflow. Today, a number of methods have been used in HT catalyst studies, including various optical, mass-spectrometry, and gas-chromatography techniques. Of these, rapid-scanning Fourier-transform infrared (FTIR imaging is one of the fastest and most versatile screening techniques. Here, the new design of the 16-channel HT reactor is presented and test results for its accuracy and reproducibility are shown. The performance of the system was evaluated through the oxidation of CO over commercial Pd/Al2O3 and cobalt oxide nanoparticles synthesized with different reducer-reductant molar ratios, surfactant types, metal and surfactant concentrations, synthesis temperatures, and ramp rates.

  1. Determination of Oxidized Phosphatidylcholines by Hydrophilic Interaction Liquid Chromatography Coupled to Fourier Transform Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Pia Sala

    2015-04-01

    Full Text Available A novel liquid chromatography-mass spectrometry (LC-MS approach for analysis of oxidized phosphatidylcholines by an Orbitrap Fourier Transform mass spectrometer in positive electrospray ionization (ESI coupled to hydrophilic interaction liquid chromatography (HILIC was developed. This method depends on three selectivity criteria for separation and identification: retention time, exact mass at a resolution of 100,000 and collision induced dissociation (CID fragment spectra in a linear ion trap. The process of chromatography development showed the best separation properties with a silica-based Kinetex column. This type of chromatography was able to separate all major lipid classes expected in mammalian samples, yielding increased sensitivity of oxidized phosphatidylcholines over reversed phase chromatography. Identification of molecular species was achieved by exact mass on intact molecular ions and CID tandem mass spectra containing characteristic fragments. Due to a lack of commercially available standards, method development was performed with copper induced oxidation products of palmitoyl-arachidonoyl-phosphatidylcholine, which resulted in a plethora of lipid species oxidized at the arachidonoyl moiety. Validation of the method was done with copper oxidized human low-density lipoprotein (LDL prepared by ultracentrifugation. In these LDL samples we could identify 46 oxidized molecular phosphatidylcholine species out of 99 possible candidates.

  2. Line width and line shape analysis in the inductively coupled plasma by high resolution Fourier transform spectrometry

    International Nuclear Information System (INIS)

    Faires, L.M.; Palmer, B.A.; Brault, J.W.

    1984-01-01

    High resolution Fourier transform spectrometry has been used to perform line width and line shape analysis of eighty-one iron I emision lines in the spectral range 290 to 390nm originating in the normal analytical zone of an inductively coupled plasma. Computer programs using non-linear least squares fitting techniques for line shape analysis were applied to the fully resolved spectra to determine Gaussian and Lorentzian components of the total observed line width. The effect of noise in the spectrum on the precision of the line fitting technique was assessed, and the importance of signal to noise ratio for line shape analysis is discussed. Translational (Doppler) temperatures were calculated from the Gaussian components of the line width and were found to be on the order of 6300 0 K. The excitation temperature of iron I was also determined from the same spectral data by the spectroscopic slope method based on the Einstein-Boltzmann expression for spectral intensity and was found to be on the order of 4700 0 K. 31 references

  3. Rapid characterization of the chemical constituents of Sijunzi decoction by UHPLC coupled with Fourier transform ion cyclotron resonance mass spectrometry.

    Science.gov (United States)

    Guan, Zhibo; Wang, Miao; Cai, Yi; Yang, Hongmei; Zhao, Min; Zhao, Chunjie

    2018-06-01

    Sijunzi decoction, a renowned Chinese prescription has long been utilized to treat gastrointestinal problems. In the context of this research work, the use of Ultra high performance liquid chromatography combined with Fourier transform ion cyclotron resonance mass spectrometry was made to separate and characterize the components of Sijunzi decoction. The performance of Liquid chromatography was carried out on a C8 column (150 mm × 2.1 mm, 1.8 μm); moreover, the mobile phase were consisted of 0.2% formic acid (A) and acetonitrile (B). In accordance with the findings, characterization of 120 chemical compounds was performed by liquid chromatography with mass spectrometry. The key constituents among them included ginsenosides (in Radix Ginseng), 16 triterpene carboxylic acids (in Poria), sesquiterpenes (in Rhizoma Atractylodis Macrocephalae), triterpenesaponins (in Glycyrrhizae Radix et Rhizoma Praeparata Cum Melle) as well as flavonoids (in Glycyrrhizae Radix et Rhizoma Praeparata Cum Melle) in Sijunzi decoction. This research developed the bases for prospective research associated with Sijunzi decoction, together with being expected to be useful to rapidly extract and characterize the constituents in other Traditional Chinese herbal formulations. Copyright © 2018 Elsevier B.V. All rights reserved.

  4. The Role of Ultrahigh Resolution Fourier Transform Mass Spectrometry (FT-MS in Astrobiology-Related Research: Analysis of Meteorites and Tholins

    Directory of Open Access Journals (Sweden)

    Árpád Somogyi

    2016-03-01

    Full Text Available It is an important but also a challenging analytical problem to understand the chemical composition and structure of prebiotic organic matter that is present in extraterrestrial materials. Its formation, evolution and content in the building blocks (“seeds” for more complex molecules, such as proteins and DNA, are key questions in the field of exobiology. Ultrahigh resolution mass spectrometry is one of the best analytical techniques that can be applied because it provides reliable information on the chemical composition and structure of individual components of complex organic mixtures. Prebiotic organic material is delivered to Earth by meteorites or generated in laboratories in simulation (model experiments that mimic space or atmospheric conditions. Recent representative examples for ultrahigh resolution mass spectrometry studies using Fourier-transform (FT mass spectrometers such as Orbitrap and ion cyclotron resonance (ICR mass spectrometers are shown and discussed in the present article, including: (i the analysis of organic matter of meteorites; (ii modeling atmospheric processes in ICR cells; and (iii the structural analysis of laboratory made tholins that might be present in the atmosphere and surface of Saturn’s largest moon, Titan.

  5. The Role of Ultrahigh Resolution Fourier Transform Mass Spectrometry (FT-MS) in Astrobiology-Related Research: Analysis of Meteorites and Tholins

    Science.gov (United States)

    Somogyi, Árpád; Thissen, Roland; Orthous-Daunay, Francois-Régis; Vuitton, Véronique

    2016-01-01

    It is an important but also a challenging analytical problem to understand the chemical composition and structure of prebiotic organic matter that is present in extraterrestrial materials. Its formation, evolution and content in the building blocks (“seeds”) for more complex molecules, such as proteins and DNA, are key questions in the field of exobiology. Ultrahigh resolution mass spectrometry is one of the best analytical techniques that can be applied because it provides reliable information on the chemical composition and structure of individual components of complex organic mixtures. Prebiotic organic material is delivered to Earth by meteorites or generated in laboratories in simulation (model) experiments that mimic space or atmospheric conditions. Recent representative examples for ultrahigh resolution mass spectrometry studies using Fourier-transform (FT) mass spectrometers such as Orbitrap and ion cyclotron resonance (ICR) mass spectrometers are shown and discussed in the present article, including: (i) the analysis of organic matter of meteorites; (ii) modeling atmospheric processes in ICR cells; and (iii) the structural analysis of laboratory made tholins that might be present in the atmosphere and surface of Saturn’s largest moon, Titan. PMID:27023520

  6. Image reconstruction from pairs of Fourier-transform magnitude

    International Nuclear Information System (INIS)

    Hunt, B.R.; Overman, T.L.; Gough, P.

    1998-01-01

    The retrieval of phase information from only the magnitude of the Fourier transform of a signal remains an important problem for many applications. We present an algorithm for phase retrieval when there exist two related sets of Fourier-transform magnitude data. The data are assumed to come from a single object observed in two different polarizations through a distorting medium, so the phase component of the Fourier transform of the object is corrupted. Phase retrieval is accomplished by minimization of a suitable criterion function, which can take three different forms. copyright 1998 Optical Society of America

  7. The relationship between shock response spectrum and fast Fourier transform

    International Nuclear Information System (INIS)

    Zola, Maurizio

    2001-01-01

    In this paper the basic relationship between response spectrum and fast Fourier transform is laid down. Since a long time the response spectrum has been used by structural engineers in the seismic domain and nowadays it is going to be used to define transient motions. This way to define the excitation is more general and more real than the use of classical shape pulses for the reproduction of real environment. Nevertheless the response spectrum of a real excitation represents a loss of some information with respect to the Fourier transform. A useful discussion could arise from these observations. Appendix A gives the relationship between the mathematic Fourier transform and the digital Fourier transform given by computers, while Appendix B gives some examples of response spectra and Fourier transforms of simple functions. (author)

  8. Mass measurement errors of Fourier-transform mass spectrometry (FTMS): distribution, recalibration, and application.

    Science.gov (United States)

    Zhang, Jiyang; Ma, Jie; Dou, Lei; Wu, Songfeng; Qian, Xiaohong; Xie, Hongwei; Zhu, Yunping; He, Fuchu

    2009-02-01

    The hybrid linear trap quadrupole Fourier-transform (LTQ-FT) ion cyclotron resonance mass spectrometer, an instrument with high accuracy and resolution, is widely used in the identification and quantification of peptides and proteins. However, time-dependent errors in the system may lead to deterioration of the accuracy of these instruments, negatively influencing the determination of the mass error tolerance (MET) in database searches. Here, a comprehensive discussion of LTQ/FT precursor ion mass error is provided. On the basis of an investigation of the mass error distribution, we propose an improved recalibration formula and introduce a new tool, FTDR (Fourier-transform data recalibration), that employs a graphic user interface (GUI) for automatic calibration. It was found that the calibration could adjust the mass error distribution to more closely approximate a normal distribution and reduce the standard deviation (SD). Consequently, we present a new strategy, LDSF (Large MET database search and small MET filtration), for database search MET specification and validation of database search results. As the name implies, a large-MET database search is conducted and the search results are then filtered using the statistical MET estimated from high-confidence results. By applying this strategy to a standard protein data set and a complex data set, we demonstrate the LDSF can significantly improve the sensitivity of the result validation procedure.

  9. Benefits of 2.94 μm infrared matrix-assisted laser desorption/ionization for analysis of labile molecules by Fourier transform mass spectrometry

    DEFF Research Database (Denmark)

    Budnik, Bogdan A.; Jensen, Kenneth Bendix; Jørgensen, Thomas J. D.

    2000-01-01

    A 2.94 microm Er:YAG laser was used together with a commercial Fourier transform mass spectrometer to study labile biomolecules. The combination has shown superior performance over conventional 337 nm ultraviolet matrix-assisted laser desorption/ionization (UV-MALDI) Fourier transform mass...

  10. Direct fourier method reconstruction based on unequally spaced fast fourier transform

    International Nuclear Information System (INIS)

    Wu Xiaofeng; Zhao Ming; Liu Li

    2003-01-01

    First, We give an Unequally Spaced Fast Fourier Transform (USFFT) method, which is more exact and theoretically more comprehensible than its former counterpart. Then, with an interesting interpolation scheme, we discusse how to apply USFFT to Direct Fourier Method (DFM) reconstruction of parallel projection data. At last, an emulation experiment result is given. (authors)

  11. Progress in static fourier transform infrared spectroscopy: assessment of sifti preliminary performances

    Science.gov (United States)

    Hébert, Philippe; Pierangelo, Clémence; Rosak, Alain; Cansot, Elodie; Bernard, Frédéric; Camy-Peyret, Claude

    2017-11-01

    The concept of static Fourier transform interferometry at thermal infrared wavelengths is well suited in the case of narrow spectral bands that are looked at for targeted molecular species as CO and O3 for pollution and air quality monitoring, or H20 and CO2 for weather forecast, down to the troposphere. It permits a high spectral resolution and a very good radiometric performance, with the advantage of a static interferometer, including no moving part. Along with other molecules sounded in the UV-VIS domain, as for instance in the TRAQ mission, SIFTI will provide scientists with a complete set for pollution measurements and air quality survey. Our paper presents the principles of static Fourier transform spectrometry, the work led on the instrument performance model and our study of the SIFTI instrument. We describe the instrument, its main dimensions and characteristics, and its architecture and major subsystems. We eventually make a preliminary survey of the SIFTI performance budget items. As a conclusion, we introduce the future CNES phase A study of this instrument that is started in 2006

  12. A discrete Fourier transform for virtual memory machines

    Science.gov (United States)

    Galant, David C.

    1992-01-01

    An algebraic theory of the Discrete Fourier Transform is developed in great detail. Examination of the details of the theory leads to a computationally efficient fast Fourier transform for the use on computers with virtual memory. Such an algorithm is of great use on modern desktop machines. A FORTRAN coded version of the algorithm is given for the case when the sequence of numbers to be transformed is a power of two.

  13. Robust alignment of chromatograms by statistically analyzing the shifts matrix generated by moving window fast Fourier transform cross-correlation.

    Science.gov (United States)

    Zhang, Mingjing; Wen, Ming; Zhang, Zhi-Min; Lu, Hongmei; Liang, Yizeng; Zhan, Dejian

    2015-03-01

    Retention time shift is one of the most challenging problems during the preprocessing of massive chromatographic datasets. Here, an improved version of the moving window fast Fourier transform cross-correlation algorithm is presented to perform nonlinear and robust alignment of chromatograms by analyzing the shifts matrix generated by moving window procedure. The shifts matrix in retention time can be estimated by fast Fourier transform cross-correlation with a moving window procedure. The refined shift of each scan point can be obtained by calculating the mode of corresponding column of the shifts matrix. This version is simple, but more effective and robust than the previously published moving window fast Fourier transform cross-correlation method. It can handle nonlinear retention time shift robustly if proper window size has been selected. The window size is the only one parameter needed to adjust and optimize. The properties of the proposed method are investigated by comparison with the previous moving window fast Fourier transform cross-correlation and recursive alignment by fast Fourier transform using chromatographic datasets. The pattern recognition results of a gas chromatography mass spectrometry dataset of metabolic syndrome can be improved significantly after preprocessing by this method. Furthermore, the proposed method is available as an open source package at https://github.com/zmzhang/MWFFT2. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Comparison of Fourier transform and continuous wavelet transform to study echo-planar imaging flow maps

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez G, A.; Bowtell, R.; Mansfield, P. [Area de Procesamiento Digital de Senales e Imagenes Biomedicas. Universidad Autonoma Metropolitana Iztapalapa. Mexico D.F. 09340 Mexico (Mexico)

    1998-12-31

    Velocity maps were studied combining Doyle and Mansfield method (1986) with each of the following transforms: Fourier, window Fourier and wavelet (Mexican hat). Continuous wavelet transform was compared against the two Fourier transform to determine which technique is best suited to study blood maps generated by Half Fourier Echo-Planar Imaging. Coefficient images were calculated and plots of the pixel intensity variation are presented. Finally, contour maps are shown to visualize the behavior of the blood flow in the cardiac chambers for the wavelet technique. (Author)

  15. Comparison of Fourier transform and continuous wavelet transform to study echo-planar imaging flow maps

    International Nuclear Information System (INIS)

    Rodriguez G, A.; Bowtell, R.; Mansfield, P.

    1998-01-01

    Velocity maps were studied combining Doyle and Mansfield method (1986) with each of the following transforms: Fourier, window Fourier and wavelet (Mexican hat). Continuous wavelet transform was compared against the two Fourier transform to determine which technique is best suited to study blood maps generated by Half Fourier Echo-Planar Imaging. Coefficient images were calculated and plots of the pixel intensity variation are presented. Finally, contour maps are shown to visualize the behavior of the blood flow in the cardiac chambers for the wavelet technique. (Author)

  16. Wigner distribution and fractional Fourier transform

    NARCIS (Netherlands)

    Alieva, T.; Bastiaans, M.J.

    2001-01-01

    The connection between the Wigner distribution and the squared modulus of the fractional Fourier transform - which are both well-known time-frequency representations of a signal - is established. In particular the Radon-Wigner transform is used, which relates projections of the Wigner distribution

  17. Convolution Theorem of Fractional Fourier Transformation Derived by Representation Transformation in Quantum Mechancis

    International Nuclear Information System (INIS)

    Fan Hongyi; Hao Ren; Lu Hailiang

    2008-01-01

    Based on our previous paper (Commun. Theor. Phys. 39 (2003) 417) we derive the convolution theorem of fractional Fourier transformation in the context of quantum mechanics, which seems a convenient and neat way. Generalization of this method to the complex fractional Fourier transformation case is also possible

  18. The application and improvement of Fourier transform spectrometer experiment

    Science.gov (United States)

    Liu, Zhi-min; Gao, En-duo; Zhou, Feng-qi; Wang, Lan-lan; Feng, Xiao-hua; Qi, Jin-quan; Ji, Cheng; Wang, Luning

    2017-08-01

    According to teaching and experimental requirements of Optoelectronic information science and Engineering, in order to consolidate theoretical knowledge and improve the students practical ability, the Fourier transform spectrometer ( FTS) experiment, its design, application and improvement are discussed in this paper. The measurement principle and instrument structure of Fourier transform spectrometer are introduced, and the spectrums of several common Laser devices are measured. Based on the analysis of spectrum and test, several possible improvement methods are proposed. It also helps students to understand the application of Fourier transform in physics.

  19. Geometric Representations for Discrete Fourier Transforms

    Science.gov (United States)

    Cambell, C. W.

    1986-01-01

    Simple geometric representations show symmetry and periodicity of discrete Fourier transforms (DFT's). Help in visualizing requirements for storing and manipulating transform value in computations. Representations useful in any number of dimensions, but particularly in one-, two-, and three-dimensional cases often encountered in practice.

  20. External Second Gate, Fourier Transform Ion Mobility Spectrometry: Parametric Optimization for Detection of Weapons of Mass Destruction

    Directory of Open Access Journals (Sweden)

    Edward E. Tarver

    2004-03-01

    Full Text Available Abstract: Ion mobility spectrometry (IMS is recognized as one of the most sensitive and robust techniques for the detection of narcotics, explosives and chemical warfare agents. IMS is widely used in forensic, military and security applications. Increasing threat of terrorist attacks, the proliferation of narcotics, Chemical Weapons Convention (CWC treaty verification as well as humanitarian de-mining efforts have mandated that equal importance be placed on the time required to obtain results as well as the quality of the analytical data. [1] In this regard IMS is virtually unrivaled when both speed of response and sensitivity have to be considered. [2] The problem with conventional (signal averaging IMS systems is the fixed duty cycle of the entrance gate that restricts to less than 1%, the number of available ions contributing to the measured signal. Furthermore, the signal averaging process incorporates scan-to-scan variations that degrade the spectral resolution contributing to misidentifications and false positives. With external second gate, Fourier Transform ion mobility spectrometry (FT-IMS the entrance gate frequency is variable and can be altered in conjunction with other data acquisition parameters (scan time and sampling rate to increase the spectral resolution to reduce false alarms and improve the sensitivity for early warning and contamination avoidance. In addition, with FT-IMS the entrance gate operates with a 50% duty cycle and so affords a seven-fold increase in sensitivity. Recent data on high explosives are presented to demonstrate the parametric optimization in sensitivity and resolution of our system.

  1. Fourier Transforms Simplified: Computing an Infrared Spectrum from an Interferogram

    Science.gov (United States)

    Hanley, Quentin S.

    2012-01-01

    Fourier transforms are used widely in chemistry and allied sciences. Examples include infrared, nuclear magnetic resonance, and mass spectroscopies. A thorough understanding of Fourier methods assists the understanding of microscopy, X-ray diffraction, and diffraction gratings. The theory of Fourier transforms has been presented in this "Journal",…

  2. On integral and finite Fourier transforms of continuous q-Hermite polynomials

    International Nuclear Information System (INIS)

    Atakishiyeva, M. K.; Atakishiyev, N. M.

    2009-01-01

    We give an overview of the remarkably simple transformation properties of the continuous q-Hermite polynomials H n (x vertical bar q) of Rogers with respect to the classical Fourier integral transform. The behavior of the q-Hermite polynomials under the finite Fourier transform and an explicit form of the q-extended eigenfunctions of the finite Fourier transform, defined in terms of these polynomials, are also discussed.

  3. Limited-angle three-dimensional reconstructions using Fourier transform iterations and Radon transform iterations

    International Nuclear Information System (INIS)

    Tam, K.C.; Perez-Mendez, V.

    1981-01-01

    The principles of limited-angle reconstruction of space-limited objects using the concepts of allowed cone and missing cone in Fourier space are discussed. The distortion of a point source resulting from setting the Fourier components in the missing cone to zero has been calculated mathematically, and its bearing on the convergence of an iteration scheme involving Fourier transforms has been analyzed in detail. it was found that the convergence rate is fairly insensitive to the position of the point source within the boundary of the object, apart from an edge effect which tends to enhance some parts of the boundary in reconstructing the object. Another iteration scheme involving Radon transforms was introduced and compared to the Fourier transform method in such areas as root mean square error, stability with respect to noise, and computer reconstruction time

  4. Limited-angle 3-D reconstructions using Fourier transform iterations and Radon transform iterations

    International Nuclear Information System (INIS)

    Tam, K.C.; Perez-Mendez, V.

    1979-12-01

    The principles of limited-angle reconstruction of space-limited objects using the concepts of allowed cone and missing cone in Fourier space are discussed. The distortion of a point source resulting from setting the Fourier components in the missing cone to zero was calculated mathematically, and its bearing on the convergence of an iteration scheme involving Fourier transforms was analyzed in detail. It was found that the convergence rate is fairly insensitive to the position of the point source within the boundary of the object, apart from an edge effect that tends to enhance some parts of the boundary in reconstructing the object. Another iteration scheme involving Radon transforms was introduced and compared to the Fourier transform method in such areas as root mean square error, stability with respect to noise, and computer reconstruction time. 8 figures, 2 tables

  5. Reducing aberration effect of Fourier transform lens by modifying Fourier spectrum of diffractive optical element in beam shaping optical system.

    Science.gov (United States)

    Zhang, Fang; Zhu, Jing; Song, Qiang; Yue, Weirui; Liu, Jingdan; Wang, Jian; Situ, Guohai; Huang, Huijie

    2015-10-20

    In general, Fourier transform lenses are considered as ideal in the design algorithms of diffractive optical elements (DOEs). However, the inherent aberrations of a real Fourier transform lens disturb the far field pattern. The difference between the generated pattern and the expected design will impact the system performance. Therefore, a method for modifying the Fourier spectrum of DOEs without introducing other optical elements to reduce the aberration effect of the Fourier transform lens is proposed. By applying this method, beam shaping performance is improved markedly for the optical system with a real Fourier transform lens. The experiments carried out with a commercial Fourier transform lens give evidence for this method. The method is capable of reducing the system complexity as well as improving its performance.

  6. APPLICATION OF STANDARDIZED QUALITY CONTROL PROCEDURES TO OPEN-PATH FOURIER TRANSFORM INFRARED DATA COLLECTED AT A CONCENTRATED SWINE PRODUCTION FACILITY

    Science.gov (United States)

    Open-path Fourier transform infrared (OP/FT-IR) spectrometry was used to measure the concentrations of ammonia, methane, and other atmospheric eases at a concentrated swine production facility. A total of 2200 OP/FT-IR spectra were acquired along nine different monitoring paths d...

  7. Molecular Characterization of Thiols in Fossil Fuels by Michael Addition Reaction Derivatization and Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry.

    Science.gov (United States)

    Wang, Meng; Zhao, Suoqi; Liu, Xuxia; Shi, Quan

    2016-10-04

    Thiols widely occur in sediments and fossil fuels. However, the molecular composition of these compounds is unclear due to the lack of appropriate analytical methods. In this work, a characterization method for thiols in fossil fuels was developed on the basis of Michael addition reaction derivatization followed by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS). Model thiol compound studies showed that thiols were selectively reacted with phenylvinylsulfone and transformed to sulfones with greater than 98% conversions. This method was applied to a coker naphtha, light and heavy gas oils, and crude oils from various geological sources. The results showed that long alkyl chain thiols are readily present in petroleum, which have up to 30 carbon atoms. Large DBE dispersity of thiols indicates that naphthenic and aromatic thiols are also present in the petroleum. This method is capable of detecting thiol compounds in the part per million range by weight. This method allows characterization of thiols in a complex hydrocarbon matrix, which is complementary to the comprehensive analysis of sulfur compounds in fossil fuels.

  8. Generalized Fourier transforms Fk,a

    DEFF Research Database (Denmark)

    Salem, Ben Said; Kobayashi, Toshiyuki; Ørsted, Bent

    2009-01-01

    We construct a two-parameter family of actions ωk,a of the Lie algebra by differential-difference operators on . Here, k is a multiplicity-function for the Dunkl operators, and a>0 arises from the interpolation of the Weil representation and the minimal unitary representation of the conformal gro...... of our semigroup Ωk,a provides us with (k,a) -generalized Fourier transforms , which includes the Dunkl transform ( a=2 ) and a new unitary operator ( a=1 ) as a Dunkl-type generalization of the classical Hankel transform....

  9. The Fourier Transform for Certain HyperKähler Fourfolds

    NARCIS (Netherlands)

    Shen, M.; Vial, C.

    2016-01-01

    Using a codimension-1 algebraic cycle obtained from the Poincaré line bundle, Beauville defined the Fourier transform on the Chow groups of an abelian variety A and showed that the Fourier transform induces a decomposition of the Chow ring CH∗(A). By using a codimension-2 algebraic cycle

  10. Glycine Identification in Natural Jarosites Using Laser-Desorption Fourier Transform Mass Spectrometry: Implications for the search for life on Mars

    Energy Technology Data Exchange (ETDEWEB)

    J. Michelle Kotler; Nancy W. Hinman; Beizhan Yan; Daphne L. Stoner; Jill R. Scott

    2008-04-01

    The jarosite group minerals have received increasing attention since the discovery of jarosite by the Mars Exploration Rover-Opportunity on the Martian surface. The mineral group has the ability to incorporate foreign ions in its structure leading to investigations regarding its use as an indicator of aqueous and/or biological activity on Earth and Mars. The use of laser desorption Fourier transform mass spectrometry has revealed the presence of organic matter in several jarosite samples from various worldwide locations. One of the organic cluster ions has been attributed to glycine based on results from combinations of glycine with synthetic jarosite and K2SO4. The ability to observe these organic signatures in jarosite samples with an “in situ” instrumental technique, such as employed in this study, furthers the goals of planetary geologists to determine whether signs of life (e.g., the presence of biomolecules or biomolecule precursors) can be detected in the rock record of terrestrial and extraterrestrial samples.

  11. Discrete fourier transform (DFT) analysis for applications using iterative transform methods

    Science.gov (United States)

    Dean, Bruce H. (Inventor)

    2012-01-01

    According to various embodiments, a method is provided for determining aberration data for an optical system. The method comprises collecting a data signal, and generating a pre-transformation algorithm. The data is pre-transformed by multiplying the data with the pre-transformation algorithm. A discrete Fourier transform of the pre-transformed data is performed in an iterative loop. The method further comprises back-transforming the data to generate aberration data.

  12. From Fourier Transforms to Singular Eigenfunctions for Multigroup Transport

    International Nuclear Information System (INIS)

    Ganapol, B.D.

    2001-01-01

    A new Fourier transform approach to the solution of the multigroup transport equation with anisotropic scattering and isotropic source is presented. Through routine analytical continuation, the inversion contour is shifted from the real line to produce contributions from the poles and cuts in the complex plane. The integrand along the branch cut is then recast in terms of matrix continuum singular eigenfunctions, demonstrating equivalence of Fourier transform inversion and the singular eigenfunction expansion. The significance of this paper is that it represents the initial step in revealing the intimate connection between the Fourier transform and singular eigenfunction approaches as well as serves as a basis for a numerical algorithm

  13. Comparative study on γ energy spectrum denoise by fourier and wavelet transforms

    International Nuclear Information System (INIS)

    Shi Dongsheng; Di Yuming; Zhou Chunlin

    2007-01-01

    This paper introduces the basic principle of wavelet and Fourier transforms, applies wavelet transform method to denoise γ energy spectrum of 60 Co and compares it with Fourier transform method. The result of simulation with MATLAB software tool showed that as compared with traditional Fourier transform, wavelet transform has comparatively higher accuracy for γ energy spectrum denoising and is more feasible to γ energy spectrum denoising. (authors)

  14. On the Scaled Fractional Fourier Transformation Operator

    International Nuclear Information System (INIS)

    Hong-Yi, Fan; Li-Yun, Hu

    2008-01-01

    Based on our previous study [Chin. Phys. Lett. 24 (2007) 2238] in which the Fresnel operator corresponding to classical Fresnel transform was introduced, we derive the fractional Fourier transformation operator, and the optical operator method is then enriched

  15. Application of point-to-point matching algorithms for background correction in on-line liquid chromatography-Fourier transform infrared spectrometry (LC-FTIR).

    Science.gov (United States)

    Kuligowski, J; Quintás, G; Garrigues, S; de la Guardia, M

    2010-03-15

    A new background correction method for the on-line coupling of gradient liquid chromatography and Fourier transform infrared spectrometry has been developed. It is based on the use of a point-to-point matching algorithm that compares the absorption spectra of the sample data set with those of a previously recorded reference data set in order to select an appropriate reference spectrum. The spectral range used for the point-to-point comparison is selected with minimal user-interaction, thus facilitating considerably the application of the whole method. The background correction method has been successfully tested on a chromatographic separation of four nitrophenols running acetonitrile (0.08%, v/v TFA):water (0.08%, v/v TFA) gradients with compositions ranging from 35 to 85% (v/v) acetonitrile, giving accurate results for both, baseline resolved and overlapped peaks. Copyright (c) 2009 Elsevier B.V. All rights reserved.

  16. Fourier transformations for difference analogs of the harmonic oscillator

    International Nuclear Information System (INIS)

    Askey, R.; Atakishiyev, N.M.

    1995-01-01

    The relation between the Mehler bilinear generating function for the Hermite polynomials and the kernel of the Fourier transformation that connect the spaces of coordinate and momentum is discussed. On the base of the relation the discrete analogs of the Fourier transformation for the Kravchuk and Charlier functions are considered. 6 refs

  17. The finite Fourier transform of classical polynomials

    OpenAIRE

    Dixit, Atul; Jiu, Lin; Moll, Victor H.; Vignat, Christophe

    2014-01-01

    The finite Fourier transform of a family of orthogonal polynomials $A_{n}(x)$, is the usual transform of the polynomial extended by $0$ outside their natural domain. Explicit expressions are given for the Legendre, Jacobi, Gegenbauer and Chebyshev families.

  18. Weathering trend characterization of medium-molecular weight polycyclic aromatic disulfur heterocycles by Fourier transform ion cyclotron resonance mass spectrometry.

    Science.gov (United States)

    Hegazi, Abdelrahman H; Fathalla, Eiman M; Andersson, Jan T

    2014-09-01

    Different weathering factors act to change petroleum composition once it is spilled into the environment. n-Alkanes, biomarkers, low-molecular weight polyaromatic hydrocarbons and sulfur heterocycles compositional changing in the environment have been extensively studied by different researchers and many parameters have been used for oil source identification and monitoring of weathering and biological degradation processes. In this work, we studied the fate of medium-molecular weight polycyclic aromatic disulfur heterocycles (PAS2Hs), up to ca. 900Da, of artificially weathered Flotta North Sea crude oil by ultra high-resolution Fourier transform ion cyclotron resonance mass spectrometry. It was found that PAS2Hs in studied crude oil having double bond equivalents (DBE) from 5 to 8 with a mass range from ca 316 to 582Da were less influenced even after six months artificial weathering experiment. However, compounds having DBEs 12, 11 and 10 were depleted after two, four and six months weathering, respectively. In addition, DBE 9 series was more susceptible to weathering than those of DBE 7 and 8. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Boosting Sensitivity in Liquid Chromatography–Fourier Transform Ion Cyclotron Resonance–Tandem Mass Spectrometry for Product Ion Analysis of Monoterpene Indole Alkaloids

    Directory of Open Access Journals (Sweden)

    Ryo eNakabayashi

    2015-12-01

    Full Text Available In metabolomics, the analysis of product ions in tandem mass spectrometry (MS/MS is noteworthy to chemically assign structural information. However, the development of relevant analytical methods are less advanced. Here, we developed a method to boost sensitivity in liquid chromatography–Fourier transform ion cyclotron resonance–tandem mass spectrometry analysis (MS/MS boost analysis. To verify the MS/MS boost analysis, both quercetin and uniformly labeled 13C quercetin were analyzed, revealing that the origin of the product ions is not the instrument, but the analyzed compounds resulting in sensitive product ions. Next, we applied this method to the analysis of monoterpene indole alkaloids (MIAs. The comparative analyses of MIAs having indole basic skeleton (ajmalicine, catharanthine, hirsuteine, and hirsutine and oxindole skeleton (formosanine, isoformosanine, pteropodine, isopteropodine, rhynchophylline, isorhynchophylline, and mitraphylline identified 86 and 73 common monoisotopic ions, respectively. The comparative analyses of the three pairs of stereoisomers showed more than 170 common monoisotopic ions in each pair. This method was also applied to the targeted analysis of MIAs in Catharanthus roseus and Uncaria rhynchophylla to profile indole and oxindole compounds using the product ions. This analysis is suitable for chemically assigning features of the metabolite groups, which contributes to targeted metabolome analysis.

  20. Boosting Sensitivity in Liquid Chromatography–Fourier Transform Ion Cyclotron Resonance–Tandem Mass Spectrometry for Product Ion Analysis of Monoterpene Indole Alkaloids

    Science.gov (United States)

    Nakabayashi, Ryo; Tsugawa, Hiroshi; Kitajima, Mariko; Takayama, Hiromitsu; Saito, Kazuki

    2015-01-01

    In metabolomics, the analysis of product ions in tandem mass spectrometry (MS/MS) is noteworthy to chemically assign structural information. However, the development of relevant analytical methods are less advanced. Here, we developed a method to boost sensitivity in liquid chromatography–Fourier transform ion cyclotron resonance–tandem mass spectrometry analysis (MS/MS boost analysis). To verify the MS/MS boost analysis, both quercetin and uniformly labeled 13C quercetin were analyzed, revealing that the origin of the product ions is not the instrument, but the analyzed compounds resulting in sensitive product ions. Next, we applied this method to the analysis of monoterpene indole alkaloids (MIAs). The comparative analyses of MIAs having indole basic skeleton (ajmalicine, catharanthine, hirsuteine, and hirsutine) and oxindole skeleton (formosanine, isoformosanine, pteropodine, isopteropodine, rhynchophylline, isorhynchophylline, and mitraphylline) identified 86 and 73 common monoisotopic ions, respectively. The comparative analyses of the three pairs of stereoisomers showed more than 170 common monoisotopic ions in each pair. This method was also applied to the targeted analysis of MIAs in Catharanthus roseus and Uncaria rhynchophylla to profile indole and oxindole compounds using the product ions. This analysis is suitable for chemically assigning features of the metabolite groups, which contributes to targeted metabolome analysis. PMID:26734034

  1. Supercontinuum Fourier transform spectrometry with balanced detection on a single photodiode

    International Nuclear Information System (INIS)

    Goncharov, Vasily V.; Hall, Gregory E.

    2016-01-01

    We demonstrate a method of combining a supercontinuum light source with a commercial Fourier transform spectrometer, using a novel approach to dual-beam balanced detection, implemented with phase-sensitive detection on a single light detector. A 40 dB reduction in the relative intensity noise is achieved for broadband light, analogous to conventional balanced detection methods using two matched photodetectors. Unlike conventional balanced detection, however, this method exploits the time structure of the broadband source to interleave signal and reference pulse trains in the time domain, recording the broadband differential signal at the fundamental pulse repetition frequency of the supercontinuum. The method is capable of real-time correction for instability in the supercontinuum spectral structure over a broad range of wavelengths and is compatible with commercially designed spectrometers. A proof-of-principle experimental setup is demonstrated for weak absorption in the 1500-1600 nm region.

  2. Internal calibration on adjacent samples (InCAS) with Fourier transform mass spectrometry.

    Science.gov (United States)

    O'Connor, P B; Costello, C E

    2000-12-15

    Using matrix-assisted laser desorption/ionization (MAL DI) on a trapped ion mass spectrometer such as a Fourier transform mass spectrometer (FTMS) allows accumulation of ions in the cell from multiple laser shots prior to detection. If ions from separate MALDI samples are accumulated simultaneously in the cell, ions from one sample can be used to calibrate ions from the other sample. Since the ions are detected simultaneously in the cell, this is, in effect, internal calibration, but there are no selective desorption effects in the MALDI source. This method of internal calibration with adjacent samples is demonstrated here on cesium iodide clusters, peptides, oligosaccharides, poly(propylene glycol), and fullerenes and provides typical FTMS internal calibration mass accuracy of < 1 ppm.

  3. Fast Fourier transform telescope

    International Nuclear Information System (INIS)

    Tegmark, Max; Zaldarriaga, Matias

    2009-01-01

    We propose an all-digital telescope for 21 cm tomography, which combines key advantages of both single dishes and interferometers. The electric field is digitized by antennas on a rectangular grid, after which a series of fast Fourier transforms recovers simultaneous multifrequency images of up to half the sky. Thanks to Moore's law, the bandwidth up to which this is feasible has now reached about 1 GHz, and will likely continue doubling every couple of years. The main advantages over a single dish telescope are cost and orders of magnitude larger field-of-view, translating into dramatically better sensitivity for large-area surveys. The key advantages over traditional interferometers are cost (the correlator computational cost for an N-element array scales as Nlog 2 N rather than N 2 ) and a compact synthesized beam. We argue that 21 cm tomography could be an ideal first application of a very large fast Fourier transform telescope, which would provide both massive sensitivity improvements per dollar and mitigate the off-beam point source foreground problem with its clean beam. Another potentially interesting application is cosmic microwave background polarization.

  4. Metabolic profile of Kudiezi injection in rats by UHPLC coupled with Fourier transform ion cyclotron resonance mass spectrometry.

    Science.gov (United States)

    Zhang, Jingdan; Zhang, Xiaoxue; Zhao, Yangyang; Song, Aihua; Sun, Wei; Yin, Ran

    2018-02-01

    In this study, a reliable and sensitive ultra-high performance liquid chromatography coupled with fourier transform ion cyclotron resonance mass spectrometry method was developed for the systematic study of the metabolic profile of Kudiezi injection in rat plasma, bile, urine, and feces after intravenous administration of a single dose. The chromatographic separation was performed on an Agilent Eclipse Plus C 18 column (4.6 mm × 50 mm, 1.8 μm) and the identification of prototype components and metabolites was achieved on a Bruker Solarix 7.0 T ultra-high resolution spectrometer in negative ion mode. Results indicated that a total of 76 constituents including 29 prototype compounds and 47 metabolites (10 phase I metabolites and 37 phase II metabolites) were tentatively identified. And the metabolic pathways of these prototype compounds including hydroxylation, dehydrogenation, glucuronidation, and sulfate conjugation. In conclusion, the developed method with high resolution and sensitivity was effective for screening and identification of prototypes and metabolites of Kudiezi injection in vivo. Moreover, these results would provide significant information for further pharmacokinetic and pharmacological research of Kudiezi injection in vivo. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. The PROSAIC Laplace and Fourier Transform

    International Nuclear Information System (INIS)

    Smith, G.A.

    1994-01-01

    Integral Transform methods play an extremely important role in many branches of science and engineering. The ease with which many problems may be solved using these techniques is well known. In Electrical Engineering especially, Laplace and Fourier Transforms have been used for a long time as a way to change the solution of differential equations into trivial algebraic manipulations or to provide alternate representations of signals and data. These techniques, while seemingly overshadowed by today's emphasis on digital analysis, still form an invaluable basis in the understanding of systems and circuits. A firm grasp of the practical aspects of these subjects provides valuable conceptual tools. This tutorial paper is a review of Laplace and Fourier Transforms from an applied perspective with an emphasis on engineering applications. The interrelationship of the time and frequency domains will be stressed, in an attempt to comfort those who, after living so much of their lives in the time domain, find thinking in the frequency domain disquieting

  6. Fourier transforms and convolutions for the experimentalist

    CERN Document Server

    Jennison, RC

    1961-01-01

    Fourier Transforms and Convolutions for the Experimentalist provides the experimentalist with a guide to the principles and practical uses of the Fourier transformation. It aims to bridge the gap between the more abstract account of a purely mathematical approach and the rule of thumb calculation and intuition of the practical worker. The monograph springs from a lecture course which the author has given in recent years and for which he has drawn upon a number of sources, including a set of notes compiled by the late Dr. I. C. Browne from a series of lectures given by Mr. J . A. Ratcliffe of t

  7. Fourier transform infrared spectroscopic study of intact cells of the nitrogen-fixing bacterium Azospirillum brasilense

    Science.gov (United States)

    Kamnev, A. A.; Ristić, M.; Antonyuk, L. P.; Chernyshev, A. V.; Ignatov, V. V.

    1997-06-01

    The data of Fourier transform infrared (FTIR) spectroscopic measurements performed on intact cells of the soil nitrogen-fixing bacterium Azospirillum brasilense grown in a standard medium and under the conditions of an increased metal uptake are compared and discussed. The structural FTIR information obtained is considered together with atomic absorption spectrometry (AAS) data on the content of metal cations in the bacterial cells. Some methodological aspects concerning preparation of bacterial cell samples for FTIR measurements are also discussed.

  8. Causal Correlation Functions and Fourier Transforms: Application in Calculating Pressure Induced Shifts

    Science.gov (United States)

    Ma, Q.; Tipping, R. H.; Lavrentieva, N. N.

    2012-01-01

    By adopting a concept from signal processing, instead of starting from the correlation functions which are even, one considers the causal correlation functions whose Fourier transforms become complex. Their real and imaginary parts multiplied by 2 are the Fourier transforms of the original correlations and the subsequent Hilbert transforms, respectively. Thus, by taking this step one can complete the two previously needed transforms. However, to obviate performing the Cauchy principal integrations required in the Hilbert transforms is the greatest advantage. Meanwhile, because the causal correlations are well-bounded within the time domain and band limited in the frequency domain, one can replace their Fourier transforms by the discrete Fourier transforms and the latter can be carried out with the FFT algorithm. This replacement is justified by sampling theory because the Fourier transforms can be derived from the discrete Fourier transforms with the Nyquis rate without any distortions. We apply this method in calculating pressure induced shifts of H2O lines and obtain more reliable values. By comparing the calculated shifts with those in HITRAN 2008 and by screening both of them with the pair identity and the smooth variation rules, one can conclude many of shift values in HITRAN are not correct.

  9. Fourier transform resampling: Theory and application

    International Nuclear Information System (INIS)

    Hawkins, W.G.

    1996-01-01

    One of the most challenging problems in medical imaging is the development of reconstruction algorithms for nonstandard geometries. This work focuses on the application of Fourier analysis to the problem of resampling or rebinning. Conventional resampling methods utilizing some form of interpolation almost always result in a loss of resolution in the tomographic image. Fourier Transform Resampling (FTRS) offers potential improvement because the Modulation Transfer Function (MTF) of the process behaves like an ideal low pass filter. The MTF, however, is nonstationary if the coordinate transformation is nonlinear. FTRS may be viewed as a generalization of the linear coordinate transformations of standard Fourier analysis. Simulated MTF's were obtained by projecting point sources at different transverse positions in the flat fan beam detector geometry. These MTF's were compared to the closed form expression for FIRS. Excellent agreement was obtained for frequencies at or below the estimated cutoff frequency. The resulting FTRS algorithm is applied to simulations with symmetric fan beam geometry, an elliptical orbit and uniform attenuation, with a normalized root mean square error (NRME) of 0.036. Also, a Tc-99m point source study (1 cm dia., placed in air 10 cm from the COR) for a circular fan beam acquisition was reconstructed with a hybrid resampling method. The FWHM of the hybrid resampling method was 11.28 mm and compares favorably with a direct reconstruction (FWHM: 11.03 mm)

  10. FOURIER SERIES MODELS THROUGH TRANSFORMATION

    African Journals Online (AJOL)

    DEPT

    monthly temperature data (1996 – 2005) collected from the National Root ... KEY WORDS: Fourier series, square transformation, multiplicative model, ... fluctuations or movements are often periodic(Ekpeyong,2005). .... significant trend or not, if the trend is not significant, the grand mean may be used as an estimate of trend.

  11. Fourier transform in multimode systems in the Bargmann representation

    International Nuclear Information System (INIS)

    Lei, C; Vourdas, A

    2007-01-01

    A Fourier transform in a multimode system is studied, using the Bargmann representation. The growth of a Bargmann function is shown to be related to the second-order correlation of the corresponding state. Both the total growth and the total second-order correlation remain unchanged under the Fourier transform. Examples with coherent states, squeezed states and Mittag-Leffler states are discussed

  12. Fourier transform infrared spectra applications to chemical systems

    CERN Document Server

    Ferraro, John R

    1978-01-01

    Fourier Transform Infrared Spectroscopy: Applications to Chemical Systems presents the chemical applications of the Fourier transform interferometry (FT-IR).The book contains discussions on the applications of FT-IR in the fields of chromatography FT-IR, polymers and biological macromolecules, emission spectroscopy, matrix isolation, high-pressure interferometry, and far infrared interferometry. The final chapter is devoted to the presentation of the use of FT-IR in solving national technical problems such as air pollution, space exploration, and energy related subjects.Researc

  13. Fourier transform infrared spectra applications to chemical systems

    CERN Document Server

    Ferraro, John R

    1985-01-01

    The final and largest volume to complete this four-volume treatise is published in response to the intense commercial and research interest in Fourier Transform Interferometry.Presenting current information from leading experts in the field, Volume 4 introduces new information on, for example, applications of Diffuse Reflectance Spectroscopy in the Far-Infrared Region. The editors place emphasis on surface studies and address advances in Capillary Gas Chromatography - Fourier Transform Interferometry.Volume 4 especially benefits spectroscopists and physicists, as well as researchers

  14. Investigation of bio-oil produced by hydrothermal liquefaction of food waste using ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry.

    Science.gov (United States)

    Kostyukevich, Yury; Vlaskin, Mikhail; Borisova, Ludmila; Zherebker, Alexander; Perminova, Irina; Kononikhin, Alexey; Popov, Igor; Nikolaev, Eugene

    2018-02-01

    Recent research has revealed that more than 1.3 billion tons of food is wasted globally every year. The disposal of such huge biomass has become a challenge. In the present paper, we report the production of the bio-oil by hydrothermal liquefaction of three classes of food waste: meat, cheese and fruits. The highest yield of the bio-oil was observed for meat (∼60%) and cheese (∼75%), while for fruits, it was considerably low (∼10%). The molecular composition of the obtained bio-oil was investigated using ultrahigh resolution Fourier Transform Ion Cyclotron Resonance mass spectrometry and was found to be similar to that obtained from algae. Several thousand heteroatom compounds (N, N 2 , ON 2 , etc. classes) were reliably identified from each sample. It was found that bio-oils produced from meat and cheese have many compounds (∼90%) with common molecular formulas, while bio-oil produced from fruits differs considerably (∼30% of compounds are unique).

  15. Multichannel Dynamic Fourier-Transform IR Spectrometer

    Science.gov (United States)

    Balashov, A. A.; Vaguine, V. A.; Golyak, Il. S.; Morozov, A. N.; Khorokhorin, A. I.

    2017-09-01

    A design of a multichannel continuous scan Fourier-transform IR spectrometer for simultaneous recording and analysis of the spectral characteristics of several objects is proposed. For implementing the design, a multi-probe fiber is used, constructed from several optical fibers connected into a single optical connector and attached at the output of the interferometer. The Fourier-transform spectrometer is used as a signal modulator. Each fiber is individually mated with an investigated sample and a dedicated radiation detector. For the developed system, the radiation intensity of the spectrometer is calculated from the condition of the minimum spectral resolution and parameters of the optical fibers. Using the proposed design, emission spectra of a gas-discharge neon lamp have been recorded using a single fiber 1 mm in diameter with a numerical aperture NA = 0.22.

  16. Solution of 3-dimensional diffusion equation by finite Fourier transformation

    International Nuclear Information System (INIS)

    Krishnani, P.D.

    1978-01-01

    Three dimensional diffusion equation in Cartesian co-ordinates is solved by using the finite Fourier transformation. This method is different from the usual Fourier transformation method in the sense that the solutions are obtained without performing the inverse Fourier transformation. The advantage has been taken of the fact that the flux is finite and integrable in the finite region. By applying this condition, a two-dimensional integral equation, involving flux and its normal derivative at the boundary, is obtained. By solving this equation with given boundary conditions, all of the boundary values are determined. In order to calculate the flux inside the region, flux is expanded into three-dimensional Fourier series. The Fourier coefficients of the flux in the region are calculated from the boundary values. The advantage of this method is that the integrated flux is obtained without knowing the fluxes inside the region as in the case of finite difference method. (author)

  17. The prosaic Laplace and Fourier transform

    International Nuclear Information System (INIS)

    Smith, G.A.

    1995-01-01

    Integral Transform methods play an extremely important role in many branches of science and engineering. The ease with which many problems may be solved using these techniques is well known. In Electrical Engineering especially, Laplace and Fourier Transforms have been used for a long time as a way to change the solution of differential equations into trivial algebraic manipulations or to provide alternate representations of signals and data. These techniques, while seemingly overshadowed by today's emphasis on digital analysis, still form an invaluable basis in the understanding of systems and circuits. A firm grasp of the practical aspects of these subjects provides valuable conceptual tools. This tutorial paper is a review of Laplace and Fourier Transforms from an applied perspective with an emphasis on engineering applications. The interrelationship of the time and frequency domains will be stressed, in an attempt to comfort those who, after living so much of their lives in the time domain, find thinking in the frequency domain disquieting. copyright 1995 American Institute of Physics

  18. Precise and fast spatial-frequency analysis using the iterative local Fourier transform.

    Science.gov (United States)

    Lee, Sukmock; Choi, Heejoo; Kim, Dae Wook

    2016-09-19

    The use of the discrete Fourier transform has decreased since the introduction of the fast Fourier transform (fFT), which is a numerically efficient computing process. This paper presents the iterative local Fourier transform (ilFT), a set of new processing algorithms that iteratively apply the discrete Fourier transform within a local and optimal frequency domain. The new technique achieves 210 times higher frequency resolution than the fFT within a comparable computation time. The method's superb computing efficiency, high resolution, spectrum zoom-in capability, and overall performance are evaluated and compared to other advanced high-resolution Fourier transform techniques, such as the fFT combined with several fitting methods. The effectiveness of the ilFT is demonstrated through the data analysis of a set of Talbot self-images (1280 × 1024 pixels) obtained with an experimental setup using grating in a diverging beam produced by a coherent point source.

  19. Glycine identification in natural jarosites using laser desorption Fourier transform mass spectrometry: implications for the search for life on Mars.

    Science.gov (United States)

    Kotler, J Michelle; Hinman, Nancy W; Yan, Beizhan; Stoner, Daphne L; Scott, Jill R

    2008-04-01

    The jarosite group minerals have received increasing attention since the discovery of jarosite on the martian surface by the Mars Exploration Rover Opportunity. Given that jarosite can incorporate foreign ions within its structure, we have investigated the use of jarosite as an indicator of aqueous and biological processes on Earth and Mars. The use of laser desorption Fourier transform mass spectrometry has revealed the presence of organic matter in several jarosite samples from various locations worldwide. One of the ions from the natural jarosites has been attributed to glycine because it was systematically observed in combinations of glycine with synthetic ammonium and potassium jarosites, Na(2)SO(4) and K(2)SO(4). The ability to observe these organic signatures in jarosite samples with an in situ instrumental technique, such as the one employed in this study, furthers the goals of planetary geologists to determine whether signs of life (e.g., the presence of biomolecules or biomolecule precursors) can be detected in the rock record of terrestrial and extraterrestrial samples.

  20. Simple optical setup implementation for digital Fourier transform holography

    Energy Technology Data Exchange (ETDEWEB)

    De Oliveira, G N [Pos-graduacao em Engenharia Mecanica, TEM/PGMEC, Universidade Federal Fluminense, Rua Passo da Patria, 156, Niteroi, R.J., Cep.: 24.210-240 (Brazil); Rodrigues, D M C; Dos Santos, P A M, E-mail: pams@if.uff.br [Instituto de Fisica, Laboratorio de Optica Nao-linear e Aplicada, Universidade Federal Fluminense, Av. Gal. Nilton Tavares de Souza, s/n, Gragoata, Niteroi, R.J., Cep.:24.210-346 (Brazil)

    2011-01-01

    In the present work a simple implementation of Digital Fourier Transform Holography (DFTH) setup is discussed. This is obtained making a very simple modification in the classical setup arquiteture of the Fourier Transform holography. It is also demonstrated the easy and practical viability of the setup in an interferometric application for mechanical parameters determination. The work is also proposed as an interesting advanced introductory training for graduated students in digital holography.

  1. Atmospheric pressure chemical ionization Fourier transform ion cyclotron resonance mass spectrometry for complex thiophenic mixture analysis

    KAUST Repository

    Hourani, Nadim

    2013-10-01

    Rationale Polycyclic aromatic sulfur heterocycles (PASHs) are detrimental species for refining processes in petroleum industry. Current mass spectrometric Methods that determine their composition are often preceded by derivatization and dopant addition approaches. Different ionization Methods have different impact on the molecular assignment of complex PASHs. The analysis of such species under atmospheric pressure chemical ionization (APCI) is still considered limited due to uncontrolled ion generation with low- and high-mass PASHs. Methods The ionization behavior of a model mixture of five selected PASH standards was investigated using an APCI source with nitrogen as the reagent gas. A complex thiophenic fraction was separated from a vacuum gas oil (VGO) and injected using the same method. The samples were analyzed using Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS). RESULTS PASH model analytes were successfully ionized and mainly [M + H]+ ions were produced. The same ionization pattern was observed for the real thiophenic sample. It was found that S1 class species were the major sulfur-containing species found in the VGO sample. These species indicated the presence of alkylated benzothiophenic (BT), dibenzothiophenic (DBT) and benzonaphthothiophenic (BNT) series that were detected by APCI-FTICR MS. CONCLUSIONS This study provides an established APCI-FTICR MS method for the analysis of complex PASHs. PASHs were detected without using any derivatization and without fragmentation. The method can be used for the analysis of S-containing crude oil samples. © 2013 John Wiley & Sons, Ltd.

  2. Discrete Fourier transform in nanostructures using scattering

    International Nuclear Information System (INIS)

    Leuenberger, Michael N.; Flatte, Michael E.; Loss, Daniel; Awschalom, D.D.

    2004-01-01

    In this article, we show that the discrete Fourier transform (DFT) can be performed by scattering a coherent particle or laser beam off an electrically controllable two-dimensional (2D) potential that has the shape of rings or peaks. After encoding the initial vector into the two-dimensional potential by means of electric gates, the Fourier-transformed vector can be read out by detectors surrounding the potential. The wavelength of the laser beam determines the necessary accuracy of the 2D potential, which makes our method very fault-tolerant. Since the time to perform the DFT is much smaller than the clock cycle of today's computers, our proposed device performs DFTs at the frequency of the computer clock speed

  3. The Fourier transform of tubular densities

    KAUST Repository

    Prior, C B; Goriely, A

    2012-01-01

    molecules. We consider tubes of both finite radii and unrestricted radius. When there is overlap of the tube structure the net density is calculated using the super-position principle. The Fourier transform of this density is composed of two expressions, one

  4. Spectrums Transform Operators in Bases of Fourier and Walsh Functions

    Directory of Open Access Journals (Sweden)

    V. V. Syuzev

    2017-01-01

    Full Text Available The problems of synthesis of the efficient algorithms for digital processing of discrete signals require transforming the signal spectra from one basis system into other. The rational solution to this problem is to construct the Fourier kernel, which is a spectrum of some basis functions, according to the system of functions of the other basis. However, Fourier kernel properties are not equally studied and described for all basis systems of practical importance. The article sets a task and presents an original way to solve the problem of mutual transformation of trigonometric Fourier spectrum into Walsh spectrum of different basis systems.The relevance of this theoretical and applied problem is stipulated, on the one hand, by the prevalence of trigonometric Fourier basis for harmonic representation of digital signals, and, on the other hand, by the fact that Walsh basis systems allow us to have efficient algorithms to simulate signals. The problem solution is achieved through building the Fourier kernel of a special structure that allows us to establish independent groups of Fourier and Walsh spectrum coefficients for further reducing the computational complexity of the transform algorithms.The article analyzes the properties of the system of trigonometric Fourier functions and shows its completeness. Considers the Walsh function basis systems in three versions, namely those of Hadamard, Paley, and Hartmut giving different ordering and analytical descriptions of the functions that make up the basis. Proves a completeness of these systems.Sequentially, for each of the three Walsh systems the analytical curves for the Fourier kernel components are obtained, and Fourier kernel themselves are built with binary rational number of samples of basis functions. The kernels are presented in matrix form and, as an example, recorded for a particular value of the discrete interval of N, equal to 8. The analysis spectral coefficients of the Fourier kernel

  5. An analogue of a theorem of Titchmarsh for Walsh-Fourier transformations

    International Nuclear Information System (INIS)

    Golubov, B I

    1998-01-01

    Let f-hat c be the Fourier cosine transform of f. Then, as proved for functions of class L p (R + ) in Titchmarsh's book 'Introduction to the theory of Fourier integrals' (1937), the Hardy operator and the Hardy-Littlewood operator can be defined. In the present paper similar equalities are proved for functions of class L p (R + ), 1< p≤2, and the Walsh-Fourier transformation

  6. Implementation of Period-Finding Algorithm by Means of Simulating Quantum Fourier Transform

    Directory of Open Access Journals (Sweden)

    Zohreh Moghareh Abed

    2010-01-01

    Full Text Available In this paper, we introduce quantum fourier transform as a key ingredient for many useful algorithms. These algorithms make a solution for problems which is considered to be intractable problems on a classical computer. Quantum Fourier transform is propounded as a key for quantum phase estimation algorithm. In this paper our aim is the implementation of period-finding algorithm.Quantum computer solves this problem, exponentially faster than classical one. Quantum phase estimation algorithm is the key for the period-finding problem .Therefore, by means of simulating quantum Fourier transform, we are able to implement the period-finding algorithm. In this paper, the simulation of quantum Fourier transform is carried out by Matlab software.

  7. Electro-optic imaging Fourier transform spectrometer

    Science.gov (United States)

    Chao, Tien-Hsin (Inventor); Znod, Hanying (Inventor)

    2009-01-01

    An Electro-Optic Imaging Fourier Transform Spectrometer (EOIFTS) for Hyperspectral Imaging is described. The EOIFTS includes an input polarizer, an output polarizer, and a plurality of birefringent phase elements. The relative orientations of the polarizers and birefringent phase elements can be changed mechanically or via a controller, using ferroelectric liquid crystals, to substantially measure the spectral Fourier components of light propagating through the EIOFTS. When achromatic switches are used as an integral part of the birefringent phase elements, the EIOFTS becomes suitable for broadband applications, with over 1 micron infrared bandwidth.

  8. Large quantum Fourier transforms are never exactly realized by braiding conformal blocks

    International Nuclear Information System (INIS)

    Freedman, Michael H.; Wang, Zhenghan

    2007-01-01

    Fourier transform is an essential ingredient in Shor's factoring algorithm. In the standard quantum circuit model with the gate set {U(2), controlled-NOT}, the discrete Fourier transforms F N =(ω ij ) NxN , i,j=0,1,...,N-1, ω=e 2πi at ∼sol∼ at N , can be realized exactly by quantum circuits of size O(n 2 ), n=ln N, and so can the discrete sine or cosine transforms. In topological quantum computing, the simplest universal topological quantum computer is based on the Fibonacci (2+1)-topological quantum field theory (TQFT), where the standard quantum circuits are replaced by unitary transformations realized by braiding conformal blocks. We report here that the large Fourier transforms F N and the discrete sine or cosine transforms can never be realized exactly by braiding conformal blocks for a fixed TQFT. It follows that an approximation is unavoidable in the implementation of Fourier transforms by braiding conformal blocks

  9. The RC Circuit: An Approach with Fourier Transforms In this article ...

    Indian Academy of Sciences (India)

    CLASSROOM. Mitrajyoti Ghosh. 83, Mitrapara 2nd Lane, Harinavi,. Kolkata 700148, West Bengal,. India. Email: mijospeakingnow@gmail.com. The RC Circuit: An Approach with Fourier Transforms. In this article we shall mathematically analyse the Resistor-. Capacitor (RC) circuit with the help of Fourier transforms. (FT).

  10. COMPARISON OF AN INNOVATIVE NONLINEAR ALGORITHM TO CLASSICAL LEAST SQUARES FOR ANALYZING OPEN-PATH FOURIER TRANSFORM INFRARED SPECTRA COLLECTED AT A CONCENTRATED SWINE PRODUCTION FACILITY

    Science.gov (United States)

    Open-path Fourier transform infrared (OP/FTIR) spectrometry was used to measure the concentrations of ammonia, methane, and other atmospheric gases at an integrated swine production facility. The concentration-pathlength products of the target gases at this site often exceeded th...

  11. Fourier transform of delayed fluorescence as an indicator of herbicide concentration.

    Science.gov (United States)

    Guo, Ya; Tan, Jinglu

    2014-12-21

    It is well known that delayed fluorescence (DF) from Photosystem II (PSII) of plant leaves can be potentially used to sense herbicide pollution and evaluate the effect of herbicides on plant leaves. The research of using DF as a measure of herbicides in the literature was mainly conducted in time domain and qualitative correlation was often obtained. Fourier transform is often used to analyze signals. Viewing DF signal in frequency domain through Fourier transform may allow separation of signal components and provide a quantitative method for sensing herbicides. However, there is a lack of an attempt to use Fourier transform of DF as an indicator of herbicide. In this work, the relationship between the Fourier transform of DF and herbicide concentration was theoretically modelled and analyzed, which immediately yielded a quantitative method to measure herbicide concentration in frequency domain. Experiments were performed to validate the developed method. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Limitations on continuous variable quantum algorithms with Fourier transforms

    International Nuclear Information System (INIS)

    Adcock, Mark R A; Hoeyer, Peter; Sanders, Barry C

    2009-01-01

    We study quantum algorithms implemented within a single harmonic oscillator, or equivalently within a single mode of the electromagnetic field. Logical states correspond to functions of the canonical position, and the Fourier transform to canonical momentum serves as the analogue of the Hadamard transform for this implementation. This continuous variable version of quantum information processing has widespread appeal because of advanced quantum optics technology that can create, manipulate and read Gaussian states of light. We show that, contrary to a previous claim, this implementation of quantum information processing has limitations due to a position-momentum trade-off of the Fourier transform, analogous to the famous time-bandwidth theorem of signal processing.

  13. HEART ABNORMALITY CLASSIFICATIONS USING FOURIER TRANSFORMS METHOD AND NEURAL NETWORKS

    Directory of Open Access Journals (Sweden)

    Endah Purwanti

    2014-05-01

    Full Text Available Health problems with cardiovascular system disorder are still ranked high globally. One way to detect abnormalities in the cardiovascular system especially in the heart is through the electrocardiogram (ECG reading. However, reading ECG recording needs experience and expertise, software-based neural networks has designed to help identify any abnormalities ofthe heart through electrocardiogram digital image. This image is processed using image processing methods to obtain ordinate chart which representing the heart’s electrical potential. Feature extraction using Fourier transforms which are divided into several numbers of coefficients. As the software input, Fourier transforms coefficient have been normalized. Output of this software is divided into three classes, namely heart with atrial fibrillation, coronary heart disease and normal. Maximum accuracy rate ofthis software is 95.45%, with the distribution of the Fourier transform coefficients 1/8 and number of nodes 5, while minimum accuracy rate of this software at least 68.18% by distribution of the Fourier transform coefficients 1/32 and the number of nodes 32. Overall result accuracy rate of this software has an average of86.05% and standard deviation of7.82.

  14. Fourier transform spectra of quantum dots

    Science.gov (United States)

    Damian, V.; Ardelean, I.; Armăşelu, Anca; Apostol, D.

    2010-05-01

    Semiconductor quantum dots are nanometer-sized crystals with unique photochemical and photophysical properties that are not available from either isolated molecules or bulk solids. These nanocrystals absorb light over a very broad spectral range as compared to molecular fluorophores which have very narrow excitation spectra. High-quality QDs are proper to be use in different biological and medical applications (as fluorescent labels, the cancer treatment and the drug delivery). In this article, we discuss Fourier transform visible spectroscopy of commercial quantum dots. We reveal that QDs produced by Evident Technologies when are enlightened by laser or luminescent diode light provides a spectral shift of their fluorescence spectra correlated to exciting emission wavelengths, as shown by the ARCspectroNIR Fourier Transform Spectrometer. In the final part of this paper we show an important biological application of CdSe/ZnS core-shell ODs as microbial labeling both for pure cultures of cyanobacteria (Synechocystis PCC 6803) and for mixed cultures of phototrophic and heterotrophic microorganisms.

  15. Studies of gas phase ion/molecule reactions by Fourier transform ion cyclotron resonance mass spectrometry

    International Nuclear Information System (INIS)

    Kleingeld, J.C.

    1984-01-01

    An important field in which Fourier-transform ion cyclotron resonance has useful applications is that of gas phase ion chemistry, the subject of this thesis. First, the general picture of ion-molecule reactions in the gas phase is discussed. Next, some positive ion-molecule reactions are described, whereas the remaining chapters deal with negative ion-molecule reactions. Most of these studies have been performed using the FT-ICR method. Reactions involving H 3 O - and NH 4 - ions are described whereas the other chapters deal with larger organic complexes. (Auth.)

  16. Anaerobic digestion of solid slaughterhouse waste: study of biological stabilization by Fourier Transform infrared spectroscopy and thermogravimetry combined with mass spectrometry.

    Science.gov (United States)

    Cuetos, María José; Gómez, Xiomar; Otero, Marta; Morán, Antonio

    2010-07-01

    In this paper, Fourier Transform infrared spectroscopy (FTIR) along with thermogravimetric analysis together with mass spectrometry (TG-MS analysis) were employed to study the organic matter transformation attained under anaerobic digestion of slaughterhouse waste and to establish the stability of the digestates obtained when compared with fresh wastes. Digestate samples studied were obtained from successful digestion and failed systems treating slaughterhouse waste and the organic fraction of municipal solid wastes. The FTIR spectra and TG profiles from well stabilized products (from successful digestion systems) showed an increase in the aromaticity degree and the reduction of volatile content and aliphatic structures as stabilization proceeded. On the other hand, the FTIR spectra of non-stable reactors showed a high aliphaticity degree and fat content. When comparing differential thermogravimetry (DTG) profiles of the feed and digestate samples obtained from all successful anaerobic systems, a reduction in the intensity of the low-temperature range (approximately 300 degrees C) peak was observed, while the weight loss experienced at high-temperature (450-550 degrees C) was variable for the different systems. Compared to the original waste, the intensity of the weight loss peak in the high-temperature range decreased in the reactors with higher hydraulic retention time (HRT) whereas its intensity increased and the peak was displaced to higher temperatures for the digesters with lower HRT.

  17. Fourier-transform optical microsystems

    Science.gov (United States)

    Collins, S. D.; Smith, R. L.; Gonzalez, C.; Stewart, K. P.; Hagopian, J. G.; Sirota, J. M.

    1999-01-01

    The design, fabrication, and initial characterization of a miniature single-pass Fourier-transform spectrometer (FTS) that has an optical bench that measures 1 cm x 5 cm x 10 cm is presented. The FTS is predicated on the classic Michelson interferometer design with a moving mirror. Precision translation of the mirror is accomplished by microfabrication of dovetailed bearing surfaces along single-crystal planes in silicon. Although it is miniaturized, the FTS maintains a relatively high spectral resolution, 0.1 cm-1, with adequate optical throughput.

  18. Properties of the Simpson discrete fourier transform | Singh ...

    African Journals Online (AJOL)

    The Simpson discrete Fourier transform (SDFT) and its inverse are transformations relating the time and frequency domains. In this paper we state and prove the important properties of shift, circular convolution, conjugation, time reversal and Plancherel's theorem. In addition, we provide an alternative representation of the ...

  19. The short time Fourier transform and local signals

    Science.gov (United States)

    Okumura, Shuhei

    In this thesis, I examine the theoretical properties of the short time discrete Fourier transform (STFT). The STFT is obtained by applying the Fourier transform by a fixed-sized, moving window to input series. We move the window by one time point at a time, so we have overlapping windows. I present several theoretical properties of the STFT, applied to various types of complex-valued, univariate time series inputs, and their outputs in closed forms. In particular, just like the discrete Fourier transform, the STFT's modulus time series takes large positive values when the input is a periodic signal. One main point is that a white noise time series input results in the STFT output being a complex-valued stationary time series and we can derive the time and time-frequency dependency structure such as the cross-covariance functions. Our primary focus is the detection of local periodic signals. I present a method to detect local signals by computing the probability that the squared modulus STFT time series has consecutive large values exceeding some threshold after one exceeding observation following one observation less than the threshold. We discuss a method to reduce the computation of such probabilities by the Box-Cox transformation and the delta method, and show that it works well in comparison to the Monte Carlo simulation method.

  20. Discrete Fourier Transform Analysis in a Complex Vector Space

    Science.gov (United States)

    Dean, Bruce H.

    2009-01-01

    Alternative computational strategies for the Discrete Fourier Transform (DFT) have been developed using analysis of geometric manifolds. This approach provides a general framework for performing DFT calculations, and suggests a more efficient implementation of the DFT for applications using iterative transform methods, particularly phase retrieval. The DFT can thus be implemented using fewer operations when compared to the usual DFT counterpart. The software decreases the run time of the DFT in certain applications such as phase retrieval that iteratively call the DFT function. The algorithm exploits a special computational approach based on analysis of the DFT as a transformation in a complex vector space. As such, this approach has the potential to realize a DFT computation that approaches N operations versus Nlog(N) operations for the equivalent Fast Fourier Transform (FFT) calculation.

  1. Online quench-flow electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry for elucidating kinetic and chemical enzymatic reaction mechanisms.

    Science.gov (United States)

    Clarke, David J; Stokes, Adam A; Langridge-Smith, Pat; Mackay, C Logan

    2010-03-01

    We have developed an automated quench-flow microreactor which interfaces directly to an electrospray ionization (ESI) mass spectrometer. We have used this device in conjunction with ESI Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) to demonstrate the potential of this approach for studying the mechanistic details of enzyme reactions. For the model system chosen to test this device, namely, the pre-steady-state hydrolysis of p-nitrophenyl acetate by the enzyme chymotrypsin, the kinetic parameters obtained are in good agreement with those in the literature. To our knowledge, this is the first reported use of online quench-flow coupled with FTICR MS. Furthermore, we have exploited the power of FTICR MS to interrogate the quenched covalently bound enzyme intermediate using top-down fragmentation. The accurate mass capabilities of FTICR MS permitted the nature of the intermediate to be assigned with high confidence. Electron capture dissociation (ECD) fragmentation allowed us to locate the intermediate to a five amino acid section of the protein--which includes the known catalytic residue, Ser(195). This experimental approach, which uniquely can provide both kinetic and chemical details of enzyme mechanisms, is a potentially powerful tool for studies of enzyme catalysis.

  2. Introduction to body composition assessment using the deuterium dilution technique with analysis of saliva samples by fourier transform infrared spectrometry

    International Nuclear Information System (INIS)

    2010-01-01

    For many years, the IAEA has fostered the more widespread use of stable isotope techniques to assess body composition in different population groups to address priority areas in public health nutrition in Member States. The objective is to support national and regional nutrition projects through both the IAEA's technical cooperation programme and its coordinated research projects. In particular, during the last few years, the increased access to analyses of deuterium enrichment by Fourier transform infrared (FTIR) spectrometry has increased the application of this technique in Africa, Asia and Latin America. This publication was developed by an international group of experts to provide practical, hands-on guidance in the use of this technique in settings where the analysis of deuterium enrichment in saliva samples will be made by FTIR. It is targeted at new users of this technique, for example nutritionists, analytical chemists and other professionals. More detailed information on the theoretical background and the practical application of state of the art methodologies to monitor changes in body composition can be found in an IAEA publication entitled Assessment of Body Composition and Total Energy Expenditure in Humans by Stable Isotope Techniques (IAEA Human Health Series No. 3)

  3. Study on sampling of continuous linear system based on generalized Fourier transform

    Science.gov (United States)

    Li, Huiguang

    2003-09-01

    In the research of signal and system, the signal's spectrum and the system's frequency characteristic can be discussed through Fourier Transform (FT) and Laplace Transform (LT). However, some singular signals such as impulse function and signum signal don't satisfy Riemann integration and Lebesgue integration. They are called generalized functions in Maths. This paper will introduce a new definition -- Generalized Fourier Transform (GFT) and will discuss generalized function, Fourier Transform and Laplace Transform under a unified frame. When the continuous linear system is sampled, this paper will propose a new method to judge whether the spectrum will overlap after generalized Fourier transform (GFT). Causal and non-causal systems are studied, and sampling method to maintain system's dynamic performance is presented. The results can be used on ordinary sampling and non-Nyquist sampling. The results also have practical meaning on research of "discretization of continuous linear system" and "non-Nyquist sampling of signal and system." Particularly, condition for ensuring controllability and observability of MIMO continuous systems in references 13 and 14 is just an applicable example of this paper.

  4. Complex nonlinear Fourier transform and its inverse

    International Nuclear Information System (INIS)

    Saksida, Pavle

    2015-01-01

    We study the nonlinear Fourier transform associated to the integrable systems of AKNS-ZS type. Two versions of this transform appear in connection with the AKNS-ZS systems. These two versions can be considered as two real forms of a single complex transform F c . We construct an explicit algorithm for the calculation of the inverse transform (F c ) -1 (h) for an arbitrary argument h. The result is given in the form of a convergent series of functions in the domain space and the terms of this series can be computed explicitly by means of finitely many integrations. (paper)

  5. Decay of the Fourier transform analytic and geometric aspects

    CERN Document Server

    Iosevich, Alex

    2014-01-01

    The Plancherel formula says that the L2 norm of the function is equal to the L2 norm of its Fourier transform. This implies that at least on average, the Fourier transform of an L2 function decays at infinity. This book is dedicated to the study of the rate of this decay under various assumptions and circumstances, far beyond the original L2 setting. Analytic and geometric properties of the underlying functions interact in a seamless symbiosis which underlines the wide range influences and applications of the concepts under consideration.

  6. Ultra High-Mass Resolution Paper Spray by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Kevin D. Quinn

    2012-01-01

    Full Text Available Paper Spray Ionization is an atmospheric pressure ionization technique that utilizes an offline electro-osmotic flow to generate ions off a paper medium. This technique can be performed on a Bruker SolariX Fourier transform ion cyclotron resonance mass spectrometer by modifying the existing nanospray source. High-resolution paper spray spectra were obtained for both organic and biological samples to demonstrate the benefit of linking the technique with a high-resolution mass analyzer. Error values in the range 0.23 to 2.14 ppm were obtained for calf lung surfactant extract with broadband mass resolving power (m/Δm50% above 60,000 utilizing an external calibration standard.

  7. Utility of Higher Harmonics in Electrospray Ionization Fourier Transform Electrostatic Linear Ion Trap Mass Spectrometry.

    Science.gov (United States)

    Dziekonski, Eric T; Johnson, Joshua T; McLuckey, Scott A

    2017-04-18

    Mass resolution (M/ΔM fwhm) is observed to linearly increase with harmonic order in a Fourier transform electrostatic linear ion trap (ELIT) mass spectrometer. This behavior was predicted by Grosshans and Marshall for frequency-multiple detection in a Fourier transform ion cyclotron resonance mass spectrometer only for situations when the prominent mechanism for signal decay is ion ejection from the trap. As the analyzer pressure in our ELIT chamber is relatively high, such that collisional scattering and collision-induced dissociation are expected to underlie much of the ion loss, we sought to explore the relationship between harmonic order and mass resolution. Mass resolutions of 36 900 (fundamental), 75 850 (2nd harmonic), and 108 200 (3rd harmonic) were obtained for GdO + (avg. m/z 173.919) with a transient length of 300 ms. To demonstrate that the mass resolution was truly increasing with harmonic order, the unresolved isotopes at the fundamental distribution of cytochrome c +8 (m/z ∼ 1549) were nearly baseline, resolved at the third harmonic (mass resolution ≈ 23 000) with a transient length of only 200 ms. This experiment demonstrates that, when the ion density is sufficiently low, ions with frequency differences of less than 4 Hz remain uncoalesced. Higher harmonics can be used to increase the effective mass resolution for a fixed transient length and thereby may enable the resolution of closely spaced masses, determination of a protein ion's charge state, and study of the onset of peak coalescence when the resolution at the fundamental frequency is insufficient.

  8. Accelerating the Non-equispaced Fast Fourier Transform on Commodity Graphics Hardware

    DEFF Research Database (Denmark)

    Sørensen, Thomas Sangild; Schaeffter, Tobias; Noe, Karsten Østergaard

    2008-01-01

    We present a fast parallel algorithm to compute the Non-equispaced fast Fourier transform on commodity graphics hardware (the GPU). We focus particularly on a novel implementation of the convolution step in the transform, which was previously its most time consuming part. We describe the performa......We present a fast parallel algorithm to compute the Non-equispaced fast Fourier transform on commodity graphics hardware (the GPU). We focus particularly on a novel implementation of the convolution step in the transform, which was previously its most time consuming part. We describe...

  9. Functional differential equations for the q-Fourier transform of q-Gaussians

    International Nuclear Information System (INIS)

    Umarov, S; Queiros, S M Duarte

    2010-01-01

    In this paper the question 'is the q-Fourier transform of a q-Gaussian a q'-Gaussian (with some q') up to a constant factor?' is studied for the whole range of q in (- infty, 3). This question is connected with applicability of the q-Fourier transform in the study of limit processes in nonextensive statistical mechanics. Using the functional differential equation approach we prove that the answer is affirmative if and only if 1 ≤ q < 3, excluding two particular cases of q < 1, namely q=1/2 and q=2/3. Complementarily, we discuss some applications of the q-Fourier transform to nonlinear partial differential equations such as the porous medium equation.

  10. Functional differential equations for the q-Fourier transform of q-Gaussians

    Energy Technology Data Exchange (ETDEWEB)

    Umarov, S [Department of Mathematics, Tufts University, Medford, MA (United States); Queiros, S M Duarte, E-mail: sdqueiro@gmail.co [Unilever R and D Port Sunlight, Quarry Road East, Wirral, CH63 3JW (United Kingdom)

    2010-02-05

    In this paper the question 'is the q-Fourier transform of a q-Gaussian a q'-Gaussian (with some q') up to a constant factor?' is studied for the whole range of q in (- infty, 3). This question is connected with applicability of the q-Fourier transform in the study of limit processes in nonextensive statistical mechanics. Using the functional differential equation approach we prove that the answer is affirmative if and only if 1 <= q < 3, excluding two particular cases of q < 1, namely q=1/2 and q=2/3. Complementarily, we discuss some applications of the q-Fourier transform to nonlinear partial differential equations such as the porous medium equation.

  11. Detailed characterization of bio-oil from pyrolysis of non-edible seed-cakes by Fourier Transform Infrared Spectroscopy (FTIR) and gas chromatography mass spectrometry (GC-MS) techniques.

    Science.gov (United States)

    Sugumaran, Vatsala; Prakash, Shanti; Ramu, Emmandi; Arora, Ajay Kumar; Bansal, Veena; Kagdiyal, Vivekanand; Saxena, Deepak

    2017-07-15

    Bio-oil obtained from pyrolysis is highly complicated mixture with valued chemicals. In order to reduce the complexity for unambiguous characterization of components present in bio-oil, solvent extractions using different solvents with increasing polarity have been adopted. The fractions have been analyzed by Fourier transform infrared (FTIR) spectroscopy for identifying the functional groups and Gas chromatography-mass spectrometry (GC-MS), for detailed characterization of components present in various fractions, thereby providing in-depth information at molecular level of various components in bio-oil. This paper reveals the potential of the analytical techniques in identification and brings out the similarities as well as differences in the components present in the bio-oil obtained from two non-edible oil seed-cakes, viz., Jatropha and Karanjia. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Optical movie encryption based on a discrete multiple-parameter fractional Fourier transform

    International Nuclear Information System (INIS)

    Zhong, Zhi; Zhang, Yujie; Shan, Mingguang; Wang, Ying; Zhang, Yabin; Xie, Hong

    2014-01-01

    A movie encryption scheme is proposed using a discrete multiple-parameter fractional Fourier transform and theta modulation. After being modulated by sinusoidal amplitude grating, each frame of the movie is transformed by a filtering procedure and then multiplexed into a complex signal. The complex signal is multiplied by a pixel scrambling operation and random phase mask, and then encrypted by a discrete multiple-parameter fractional Fourier transform. The movie can be retrieved by using the correct keys, such as a random phase mask, a pixel scrambling operation, the parameters in a discrete multiple-parameter fractional Fourier transform and a time sequence. Numerical simulations have been performed to demonstrate the validity and the security of the proposed method. (paper)

  13. Two-dimensional fourier transform spectrometer

    Science.gov (United States)

    DeFlores, Lauren; Tokmakoff, Andrei

    2013-09-03

    The present invention relates to a system and methods for acquiring two-dimensional Fourier transform (2D FT) spectra. Overlap of a collinear pulse pair and probe induce a molecular response which is collected by spectral dispersion of the signal modulated probe beam. Simultaneous collection of the molecular response, pulse timing and characteristics permit real time phasing and rapid acquisition of spectra. Full spectra are acquired as a function of pulse pair timings and numerically transformed to achieve the full frequency-frequency spectrum. This method demonstrates the ability to acquire information on molecular dynamics, couplings and structure in a simple apparatus. Multi-dimensional methods can be used for diagnostic and analytical measurements in the biological, biomedical, and chemical fields.

  14. An introduction to Laplace transforms and Fourier series

    CERN Document Server

    Dyke, Phil

    2014-01-01

    Laplace transforms continue to be a very important tool for the engineer, physicist and applied mathematician. They are also now useful to financial, economic and biological modellers as these disciplines become more quantitative. Any problem that has underlying linearity and with solution based on initial values can be expressed as an appropriate differential equation and hence be solved using Laplace transforms. In this book, there is a strong emphasis on application with the necessary mathematical grounding. There are plenty of worked examples with all solutions provided. This enlarged new edition includes generalised Fourier series and a completely new chapter on wavelets. Only knowledge of elementary trigonometry and calculus are required as prerequisites. An Introduction to Laplace Transforms and Fourier Series will be useful for second and third year undergraduate students in engineering, physics or mathematics, as well as for graduates in any discipline such as financial mathematics, econometrics and ...

  15. The Fourier transform of tubular densities

    International Nuclear Information System (INIS)

    Prior, C B; Goriely, A

    2012-01-01

    We consider the Fourier transform of tubular volume densities, with arbitrary axial geometry and (possibly) twisted internal structure. This density can be used to represent, among others, magnetic flux or the electron density of biopolymer molecules. We consider tubes of both finite radii and unrestricted radius. When there is overlap of the tube structure the net density is calculated using the super-position principle. The Fourier transform of this density is composed of two expressions, one for which the radius of the tube is less than the curvature of the axis and one for which the radius is greater (which must have density overlap). This expression can accommodate an asymmetric density distribution and a tube structure which has non-uniform twisting. In addition we give several simpler expressions for isotropic densities, densities of finite radius, densities which decay at a rate sufficient to minimize local overlap and finally individual surfaces of the tube manifold. These simplified cases can often be expressed as arclength integrals and can be evaluated using a system of first-order ODEs. (paper)

  16. The Fourier transform of tubular densities

    KAUST Repository

    Prior, C B

    2012-05-18

    We consider the Fourier transform of tubular volume densities, with arbitrary axial geometry and (possibly) twisted internal structure. This density can be used to represent, among others, magnetic flux or the electron density of biopolymer molecules. We consider tubes of both finite radii and unrestricted radius. When there is overlap of the tube structure the net density is calculated using the super-position principle. The Fourier transform of this density is composed of two expressions, one for which the radius of the tube is less than the curvature of the axis and one for which the radius is greater (which must have density overlap). This expression can accommodate an asymmetric density distribution and a tube structure which has non-uniform twisting. In addition we give several simpler expressions for isotropic densities, densities of finite radius, densities which decay at a rate sufficient to minimize local overlap and finally individual surfaces of the tube manifold. These simplified cases can often be expressed as arclength integrals and can be evaluated using a system of first-order ODEs. © 2012 IOP Publishing Ltd.

  17. On the moments of the Wigner distribution and the fractional Fourier transform

    NARCIS (Netherlands)

    Alieva, T.; Bastiaans, M.J.; Veen, J.P.

    2000-01-01

    A Fourier transformation maps a one-dimensional time signal into a one-dimensional frequency function, the signal spectrum. Although the Fourier transform provides the signal's spectral content, it fails to indicate the time location of the spectral components, which is important, for example, when

  18. TMS320C25 Digital Signal Processor For 2-Dimensional Fast Fourier Transform Computation

    International Nuclear Information System (INIS)

    Ardisasmita, M. Syamsa

    1996-01-01

    The Fourier transform is one of the most important mathematical tool in signal processing and analysis, which converts information from the time/spatial domain into the frequency domain. Even with implementation of the Fast Fourier Transform algorithms in imaging data, the discrete Fourier transform execution consume a lot of time. Digital signal processors are designed specifically to perform computation intensive digital signal processing algorithms. By taking advantage of the advanced architecture. parallel processing, and dedicated digital signal processing (DSP) instruction sets. This device can execute million of DSP operations per second. The device architecture, characteristics and feature suitable for fast Fourier transform application and speed-up are discussed

  19. Quantitative analysis of red wine tannins using Fourier-transform mid-infrared spectrometry.

    Science.gov (United States)

    Fernandez, Katherina; Agosin, Eduardo

    2007-09-05

    Tannin content and composition are critical quality components of red wines. No spectroscopic method assessing these phenols in wine has been described so far. We report here a new method using Fourier transform mid-infrared (FT-MIR) spectroscopy and chemometric techniques for the quantitative analysis of red wine tannins. Calibration models were developed using protein precipitation and phloroglucinolysis as analytical reference methods. After spectra preprocessing, six different predictive partial least-squares (PLS) models were evaluated, including the use of interval selection procedures such as iPLS and CSMWPLS. PLS regression with full-range (650-4000 cm(-1)), second derivative of the spectra and phloroglucinolysis as the reference method gave the most accurate determination for tannin concentration (RMSEC = 2.6%, RMSEP = 9.4%, r = 0.995). The prediction of the mean degree of polymerization (mDP) of the tannins also gave a reasonable prediction (RMSEC = 6.7%, RMSEP = 10.3%, r = 0.958). These results represent the first step in the development of a spectroscopic methodology for the quantification of several phenolic compounds that are critical for wine quality.

  20. The use of Fourier eigen transform to the boundary element method for transient elastodynamic problems

    International Nuclear Information System (INIS)

    Ji, X.; Chen, Y.M.

    1989-01-01

    The boundary element method (BEM) is developed from the boundary integral equation method and the discretization techniques. Compared with other numerical method, BEM has been shown to be a versatile and efficient method for a wide variety of engineering problems, including the wave propagation in elastic media. The first formulation and solution of the transient elastodynamic problem by combining BEM and Laplace transform is due to Cruse. Further improvement was achieved by introducing Durbin's method instead of Papoulis method of numerical Laplace inverse transform. However, a great deal of computer time is still needed for the inverse transformation. The alternative integral transform approach is BEM combining with Fourier transform. The numerical Fourier inverse transformation is also computer time consuming, even if the fast Fourier transform is used. In the present paper, the authors use BEM combining with Fourier transform and Fourier eigen transform (FET). The new approach is very attractive in saving on computer time. This paper illustrates the application of FET to BEM of 2-dimensional transient elastodynamic problem. The example of a half plane subjected to a discontinuous boundary load is solved on ELXSI 6400 computer. The CPU time is less than one minute. If Laplace or Fourier transform is adopted, the CPU time will be more than 10 minutes

  1. Reduction and coding of synthetic aperture radar data with Fourier transforms

    Science.gov (United States)

    Tilley, David G.

    1995-01-01

    Recently, aboard the Space Radar Laboratory (SRL), the two roles of Fourier Transforms for ocean image synthesis and surface wave analysis have been implemented with a dedicated radar processor to significantly reduce Synthetic Aperture Radar (SAR) ocean data before transmission to the ground. The object was to archive the SAR image spectrum, rather than the SAR image itself, to reduce data volume and capture the essential descriptors of the surface wave field. SAR signal data are usually sampled and coded in the time domain for transmission to the ground where Fourier Transforms are applied both to individual radar pulses and to long sequences of radar pulses to form two-dimensional images. High resolution images of the ocean often contain no striking features and subtle image modulations by wind generated surface waves are only apparent when large ocean regions are studied, with Fourier transforms, to reveal periodic patterns created by wind stress over the surface wave field. Major ocean currents and atmospheric instability in coastal environments are apparent as large scale modulations of SAR imagery. This paper explores the possibility of computing complex Fourier spectrum codes representing SAR images, transmitting the coded spectra to Earth for data archives and creating scenes of surface wave signatures and air-sea interactions via inverse Fourier transformations with ground station processors.

  2. Imaging properties of the mesooptical Fourier transform microscope for nuclear research emulsion

    International Nuclear Information System (INIS)

    Bencze, Gy.L.; Soroko, L.M.

    1987-01-01

    The optical signal transformation in the Mesooptical Fourier Transform Microscope (MFTM) for nuclear emulsion is treated in terms of Fourier Optics. A continuous conversion of the traditional optical microscope into the MFTM is followed. The images of dot-like and straight line objects given by the MFTM are discussed

  3. Source brightness fluctuation correction of solar absorption fourier transform mid infrared spectra

    Directory of Open Access Journals (Sweden)

    T. Ridder

    2011-06-01

    Full Text Available The precision and accuracy of trace gas observations using solar absorption Fourier Transform infrared spectrometry depend on the stability of the light source. Fluctuations in the source brightness, however, cannot always be avoided. Current correction schemes, which calculate a corrected interferogram as the ratio of the raw DC interferogram and a smoothed DC interferogram, are applicable only to near infrared measurements. Spectra in the mid infrared spectral region below 2000 cm−1 are generally considered uncorrectable, if they are measured with a MCT detector. Such measurements introduce an unknown offset to MCT interferograms, which prevents the established source brightness fluctuation correction. This problem can be overcome by a determination of the offset using the modulation efficiency of the instrument. With known modulation efficiency the offset can be calculated, and the source brightness correction can be performed on the basis of offset-corrected interferograms. We present a source brightness fluctuation correction method which performs the smoothing of the raw DC interferogram in the interferogram domain by an application of a running mean instead of high-pass filtering the corresponding spectrum after Fourier transformation of the raw DC interferogram. This smoothing can be performed with the onboard software of commercial instruments. The improvement of MCT spectra and subsequent ozone profile and total column retrievals is demonstrated. Application to InSb interferograms in the near infrared spectral region proves the equivalence with the established correction scheme.

  4. Application of Fourier transforms for microwave radiometric inversions

    Science.gov (United States)

    Holmes, J. J.; Balanis, C. A.; Truman, W. M.

    1975-01-01

    Existing microwave radiometer technology now provides a suitable method for remote determination of the ocean surface's absolute brightness temperature. To extract the brightness temperature of the water from the antenna temperature, an unstable Fredholm integral equation of the first kind is solved. Fourier transform techniques are used to invert the integral after it is placed into a cross correlation form. Application and verification of the methods to a two-dimensional modeling of a laboratory wave tank system are included. The instability of the ill-posed Fredholm equation is examined and a restoration procedure is included which smooths the resulting oscillations. With the recent availability and advances of fast Fourier transform (FFT) techniques, the method presented becomes very attractive in the evaluation of large quantities of data.

  5. Realization of quantum Fourier transform over ZN

    International Nuclear Information System (INIS)

    Fu Xiang-Qun; Bao Wan-Su; Li Fa-Da; Zhang Yu-Chao

    2014-01-01

    Since the difficulty in preparing the equal superposition state of amplitude is 1/√N, we construct a quantile transform of quantum Fourier transform (QFT) over Z N based on the elementary transforms, such as Hadamard transform and Pauli transform. The QFT over Z N can then be realized by the quantile transform, and used to further design its quantum circuit and analyze the requirements for the quantum register and quantum gates. However, the transform needs considerable quantum computational resources and it is difficult to construct a high-dimensional quantum register. Hence, we investigate the design of t-bit quantile transform, and introduce the definition of t-bit semiclassical QFT over Z N . According to probability amplitude, we prove that the transform can be used to realize QFT over Z N and further design its quantum circuit. For this transform, the requirements for the quantum register, the one-qubit gate, and two-qubit gate reduce obviously when compared with those for the QFT over Z N . (general)

  6. Rectangular-to-quincunx Gabor lattice conversion via fractional Fourier transformation

    NARCIS (Netherlands)

    Bastiaans, M.J.; Leest, van A.J.

    1998-01-01

    Transformations of Gabor lattices are associated with operations on the window functions that arise in Gabor theory. In particular it is shown that transformation from a rectangular to a quincunx lattice can be associated with fractional Fourier transformation. Since a Gaussian function, which plays

  7. Reconstruction of on-axis lensless Fourier transform digital hologram with the screen division method

    Science.gov (United States)

    Jiang, Hongzhen; Liu, Xu; Liu, Yong; Li, Dong; Chen, Zhu; Zheng, Fanglan; Yu, Deqiang

    2017-10-01

    An effective approach for reconstructing on-axis lensless Fourier Transform digital hologram by using the screen division method is proposed. Firstly, the on-axis Fourier Transform digital hologram is divided into sub-holograms. Then the reconstruction result of every sub-hologram is obtained according to the position of corresponding sub-hologram in the hologram reconstruction plane with Fourier transform operation. Finally, the reconstruction image of on-axis Fourier Transform digital hologram can be acquired by the superposition of the reconstruction result of sub-holograms. Compared with the traditional reconstruction method with the phase shifting technology, in which multiple digital holograms are required to record for obtaining the reconstruction image, this method can obtain the reconstruction image with only one digital hologram and therefore greatly simplify the recording and reconstruction process of on-axis lensless Fourier Transform digital holography. The effectiveness of the proposed method is well proved with the experimental results and it will have potential application foreground in the holographic measurement and display field.

  8. Analysis of O-glycan heterogeneity in IgA1 myeloma proteins by Fourier transform ion cyclotron resonance mass spectrometry: implications for IgA nephropathy

    DEFF Research Database (Denmark)

    Renfrow, MB; Mackay, CL; Chalmers, MJ

    2007-01-01

    deficiency in IgA1 proteins occurs randomly or preferentially at specific sites. We have previously demonstrated the first direct localization of multiple O-glycosylation sites on a single IgA1 myeloma protein by use of activated ion-electron capture dissociation (AI-ECD) Fourier transform ion cyclotron...... resonance (FT-ICR) tandem mass spectrometry. Here, we report the analysis of IgA1 O-glycan heterogeneity by use of FT-ICR MS and liquid chromatography FT-ICR MS to obtain unbiased accurate mass profiles of IgA1 HR glycopeptides from three different IgA1 myeloma proteins. Additionally, we report the first AI......-ECD fragmentation on an individual IgA1 O-glycopeptide from an IgA1 HR preparation that is reproducible for each IgA1 myeloma protein. These results suggest that future analysis of IgA1 HR from IgAN patients and normal healthy controls should be feasible....

  9. Fourier Transfrom Ion Cyclotron Resonance Mass Spectrometry at High Magnetic Field

    Science.gov (United States)

    Marshall, Alan G.

    1998-03-01

    At high magnetic field (9.4 tesla at NHMFL), Fourier transform ion cyclotron resonance mass spectrometry performance improves dramatically: mass resolving power, axialization efficiency, and scan speed (each proportional to B), maximum ion mass, dynamic range, ion trapping period, kinetic energy, and electron self-cooling rate for sympathetic cooling (each proportional to B^2), and ion coalescence tendency (proportional 1/B^2). These advantages may apply singly (e.g., unit mass resolution for proteins of >100,000 Da), or compound (e.g., 10-fold improvement in S/N ratio for 9.4 T vs. 6 T at the same resolving power). Examples range from direct determination of molecular formulas of diesel fuel components by accurate mass measurement (=B10.1 ppm) to protein structure and dynamics probed by H/D exchange. This work was supported by N.S.F. (CHE-93-22824; CHE-94-13008), N.I.H. (GM-31683), Florida State University, and the National High Magnetic Field Laboratory in Tallahassee, FL.

  10. Pipeline Analyzer using the Fractional Fourier Transform for Engine Control and Satellites Data

    Directory of Open Access Journals (Sweden)

    Darian M. Onchiș

    2011-09-01

    Full Text Available The aim of this paper is to present an algorithm for computing the fractional Fourier transform integrated into the pipeline of processing multi-variate and distributed data recorded by the engine control unit (ECU of a car and its satellites. The role of this transform is vital in establishing a time-variant filter and therefore it must be computed in a fast way. But for large scale time series, the application of the discrete fractional Fourier transform involves the computations of a large number of Hermite polynomials of increasingly order. The parallel algorithm presented will optimally compute the discrete Fourier-type transform for any given angle.

  11. Missing texture reconstruction method based on error reduction algorithm using Fourier transform magnitude estimation scheme.

    Science.gov (United States)

    Ogawa, Takahiro; Haseyama, Miki

    2013-03-01

    A missing texture reconstruction method based on an error reduction (ER) algorithm, including a novel estimation scheme of Fourier transform magnitudes is presented in this brief. In our method, Fourier transform magnitude is estimated for a target patch including missing areas, and the missing intensities are estimated by retrieving its phase based on the ER algorithm. Specifically, by monitoring errors converged in the ER algorithm, known patches whose Fourier transform magnitudes are similar to that of the target patch are selected from the target image. In the second approach, the Fourier transform magnitude of the target patch is estimated from those of the selected known patches and their corresponding errors. Consequently, by using the ER algorithm, we can estimate both the Fourier transform magnitudes and phases to reconstruct the missing areas.

  12. Nonlinear Fourier transforms for the sine-Gordon equation in the quarter plane

    Science.gov (United States)

    Huang, Lin; Lenells, Jonatan

    2018-03-01

    Using the Unified Transform, also known as the Fokas method, the solution of the sine-Gordon equation in the quarter plane can be expressed in terms of the solution of a matrix Riemann-Hilbert problem whose definition involves four spectral functions a , b , A , B. The functions a (k) and b (k) are defined via a nonlinear Fourier transform of the initial data, whereas A (k) and B (k) are defined via a nonlinear Fourier transform of the boundary values. In this paper, we provide an extensive study of these nonlinear Fourier transforms and the associated eigenfunctions under weak regularity and decay assumptions on the initial and boundary values. The results can be used to determine the long-time asymptotics of the sine-Gordon quarter-plane solution via nonlinear steepest descent techniques.

  13. Reduced Order Fractional Fourier Transform A New Variant to Fractional Signal Processing Definition and Properties

    OpenAIRE

    Kumar, Sanjay

    2018-01-01

    In this paper, a new variant to fractional signal processing is proposed known as the Reduced Order Fractional Fourier Transform. Various properties satisfied by its transformation kernel is derived. The properties associated with the proposed Reduced Order Fractional Fourier Transform like shift, modulation, time-frequency shift property are also derived and it is shown mathematically that when the rotation angle of Reduced Order Fractional Fourier Transform approaches 90 degrees, the propos...

  14. Fourier transform infrared spectroscopy in physics laboratory courses

    International Nuclear Information System (INIS)

    Möllmann, K-P; Vollmer, M

    2013-01-01

    Infrared spectrometry is one of the most important tools in the field of spectroscopic analysis. This is due to the high information content of spectra in the so-called spectroscopic fingerprint region, which enables measurement not only of gases, but also of liquids and solids. Today, infrared spectroscopy is almost completely dominated by Fourier transform infrared (FTIR) spectroscopy. FTIR spectroscopy is able to detect minute quantities in the ppm and ppb ranges, and the respective analyses are now standard tools in science as well as industry. Therefore FTIR spectroscopy should be taught within the standard curriculum at university to physicists and engineers. Here we present respective undergraduate laboratory experiments designed for students at the end of their third year. Experiments deal first with understanding the spectrometer and second with recording and analysing spectra. On the one hand, transmission spectra of gases are treated which relate to environmental analytics (being probably the most prominent and well-known examples), and on the other hand, the focus is on the transmission and reflection spectra of solids. In particular, silicon wafers are studied—as is regularly done in the microelectronics industry—in order to characterize their thickness, oxygen content and phonon modes. (paper)

  15. Revisiting the quantum harmonic oscillator via unilateral Fourier transforms

    International Nuclear Information System (INIS)

    Nogueira, Pedro H F; Castro, Antonio S de

    2016-01-01

    The literature on the exponential Fourier approach to the one-dimensional quantum harmonic oscillator problem is revised and criticized. It is shown that the solution of this problem has been built on faulty premises. The problem is revisited via the Fourier sine and cosine transform method and the stationary states are properly determined by requiring definite parity and square-integrable eigenfunctions. (paper)

  16. Phase retrieval from the magnitude of the Fourier transforms of nonperiodic objects

    International Nuclear Information System (INIS)

    Miao, J.; Sayre, D.; Chapman, H.N.

    1998-01-01

    It is suggested that, given the magnitude of Fourier transforms sampled at the Bragg density, the phase problem is underdetermined by a factor of 2 for 1D, 2D, and 3D objects. It is therefore unnecessary to oversample the magnitude of Fourier transforms by 2x in each dimension (i.e., oversampling by 4x for 2D and 8x for 3D) in retrieving the phase of 2D and 3D objects. Our computer phasing experiments accurately retrieved the phase from the magnitude of the Fourier transforms of 2D and 3D complex-valued objects by using positivity constraints on the imaginary part of the objects and loose supports, with the oversampling factor much less than 4 for 2D and 8 for 3D objects. Under the same conditions we also obtained reasonably good reconstructions of 2D and 3D complex-valued objects from the magnitude of their Fourier transforms with added noise and a central stop. copyright 1998 Optical Society of America

  17. Meso-optical Fourier transform microscope with double focusing

    International Nuclear Information System (INIS)

    Batusov, Yu.A.; Soroko, L.M.; Tereshchenko, V.V.

    1992-01-01

    The meso-optical Fourier transform microscope (MFTM) with double focusing for particle tracks of low ionization level in the nuclear emulsion is described. It is shown experimentally that this device enables one to get high concentration of information about the position of the particle track in the nuclear emulsion and thus to increase the signal-to-noise ratio. It is shown that spreading of the meso-optical image of the particle track in the sagittal section of the MFTM can be eliminated completely in the frame of the diffraction limit. The number of the additional degrees of freedom in this new MFTM system along depth coordinate is equal to 20 in comparison to single degree of freedom in the Fourier transform microscope of the direct observation. 10 refs.; 15 figs

  18. Improved Fourier-transform profilometry

    International Nuclear Information System (INIS)

    Mao Xianfu; Chen Wenjing; Su Xianyu

    2007-01-01

    An improved optical geometry of the projected-fringe profilometry technique, in which the exit pupil of the projecting lens and the entrance pupil of the imaging lens are neither at the same height above the reference plane nor coplanar, is discussed and used in Fourier-transform profilometry. Furthermore, an improved fringe-pattern description and phase-height mapping formula based on the improved geometrical generalization is deduced. Employing the new optical geometry, it is easier for us to obtain the full-field fringe by moving either the projector or the imaging device. Therefore the new method offers a flexible way to obtain reliable height distribution of a measured object

  19. Pi, Fourier Transform and Ludolph van Ceulen

    NARCIS (Netherlands)

    Vajta, Miklos

    2000-01-01

    The paper describes an interesting (and unexpected) application of the Fast Fourier transform in number theory. Calculating more and more decimals of p (first by hand and then from the mid-20th century, by digital computers) not only fascinated mathematicians from ancient times but kept them busy as

  20. DWDM-TO-OTDM Conversion by Time-Domain Optical Fourier Transformation

    DEFF Research Database (Denmark)

    Mulvad, Hans Christian Hansen; Hu, Hao; Galili, Michael

    2011-01-01

    We propose DWDM-OTDM conversion by time-domain optical Fourier transformation. Error-free conversion of a 16×10 Gbit/s 50 GHz-spacing DWDM data signal to a 160 Gbit/s OTDM signal with a 2.1 dB average penalty is demonstrated.......We propose DWDM-OTDM conversion by time-domain optical Fourier transformation. Error-free conversion of a 16×10 Gbit/s 50 GHz-spacing DWDM data signal to a 160 Gbit/s OTDM signal with a 2.1 dB average penalty is demonstrated....

  1. Application of finite Fourier transformation for the solution of the diffusion equation

    International Nuclear Information System (INIS)

    Kobayashi, Keisuke

    1991-01-01

    The application of the finite Fourier transformation to the solution of the neutron diffusion equation in one dimension, two dimensional x-y and triangular geometries is discussed. It can be shown that the equation obtained by the Nodal Green's function method in Cartesian coordinates can be derived as a special case of the finite Fourier transformation method. (author)

  2. Analysis and application of Fourier transform spectroscopy in atmospheric remote sensing

    Science.gov (United States)

    Park, J. H.

    1984-01-01

    An analysis method for Fourier transform spectroscopy is summarized with applications to various types of distortion in atmospheric absorption spectra. This analysis method includes the fast Fourier transform method for simulating the interferometric spectrum and the nonlinear least-squares method for retrieving the information from a measured spectrum. It is shown that spectral distortions can be simulated quite well and that the correct information can be retrieved from a distorted spectrum by this analysis technique.

  3. Application of phase correction to improve the interpretation of crude oil spectra obtained using 7 T Fourier transform ion cyclotron resonance mass spectrometry.

    Science.gov (United States)

    Cho, Yunju; Qi, Yulin; O'Connor, Peter B; Barrow, Mark P; Kim, Sunghwan

    2014-01-01

    In this study, a phase-correction technique was applied to the study of crude oil spectra obtained using a 7 T Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). 7 T FT-ICR MS had not been widely used for oil analysis due to the lower resolving power compared with high field FT-ICR MS. For low field instruments, usage of data that has not been phase-corrected results in an inability to resolve critical mass splits of C3 and SH4 (3.4 mDa), and (13)C and CH (4.5 mDa). This results in incorrect assignments of molecular formulae, and discontinuous double bond equivalents (DBE) and carbon number distributions of S1, S2, and hydrocarbon classes are obtained. Application of phase correction to the same data, however, improves the reliability of assignments and produces continuous DBE and carbon number distributions. Therefore, this study clearly demonstrates that phase correction improves data analysis and the reliability of assignments of molecular formulae in crude oil anlayses.

  4. High Accuracy Evaluation of the Finite Fourier Transform Using Sampled Data

    Science.gov (United States)

    Morelli, Eugene A.

    1997-01-01

    Many system identification and signal processing procedures can be done advantageously in the frequency domain. A required preliminary step for this approach is the transformation of sampled time domain data into the frequency domain. The analytical tool used for this transformation is the finite Fourier transform. Inaccuracy in the transformation can degrade system identification and signal processing results. This work presents a method for evaluating the finite Fourier transform using cubic interpolation of sampled time domain data for high accuracy, and the chirp Zeta-transform for arbitrary frequency resolution. The accuracy of the technique is demonstrated in example cases where the transformation can be evaluated analytically. Arbitrary frequency resolution is shown to be important for capturing details of the data in the frequency domain. The technique is demonstrated using flight test data from a longitudinal maneuver of the F-18 High Alpha Research Vehicle.

  5. Method of local pointed function reduction of original shape in Fourier transformation

    International Nuclear Information System (INIS)

    Dosch, H.; Slavyanov, S.Yu.

    2002-01-01

    The method for analytical reduction of the original shape in the one-dimensional Fourier transformation by the fourier image modulus is proposed. The basic concept of the method consists in the presentation of the model shape in the form of the local peak functions sum. The eigenfunctions, generated by the linear differential equations with the polynomial coefficients, are selected as the latter ones. This provides for the possibility of managing the Fourier transformation without numerical integration. This reduces the reverse task to the nonlinear regression with a small number of the evaluated parameters and to the numerical or asymptotic study on the model peak functions - the eigenfunctions of the differential tasks and their fourier images [ru

  6. Fourier transform of momentum distribution in vanadium

    International Nuclear Information System (INIS)

    Singh, A.K.; Manuel, A.A.; Peter, M.; Singru, R.M.

    1985-01-01

    Experimental Compton profile and 2D-angular correlation of positron annihilation radiation data from vanadium are analyzed by the mean of their Fourier transform. They are compared with the functions calculated with the help of both the linear muffin-tin orbital and the Hubbard-Mijnarends band structure methods. The results show that the functions are influenced by the positron wave function, by the e + -e - many-body correlations and by the differences in the electron wave functions used for the band structure calculations. It is concluded that Fourier analysis is a sensitive approach to investigate the momentum distributions in transition metals and to understnad the effects of the positron. (Auth.)

  7. Application and sensitivity investigation of Fourier transforms for microwave radiometric inversions

    Science.gov (United States)

    Holmes, J. J.; Balanis, C. A.

    1974-01-01

    Existing microwave radiometer technology now provides a suitable method for remote determination of the ocean surface's absolute brightness temperature. To extract the brightness temperature of the water from the antenna temperature equation, an unstable Fredholm integral equation of the first kind was solved. Fast Fourier Transform techniques were used to invert the integral after it is placed into a cross-correlation form. Application and verification of the methods to a two-dimensional modeling of a laboratory wave tank system were included. The instability of the Fredholm equation was then demonstrated and a restoration procedure was included which smooths the resulting oscillations. With the recent availability and advances of Fast Fourier Transform techniques, the method presented becomes very attractive in the evaluation of large quantities of data. Actual radiometric measurements of sea water are inverted using the restoration method, incorporating the advantages of the Fast Fourier Transform algorithm for computations.

  8. Comparing Laser Desorption Ionization and Atmospheric Pressure Photoionization Coupled to Fourier Transform Ion Cyclotron Resonance Mass Spectrometry To Characterize Shale Oils at the Molecular Level

    Science.gov (United States)

    Cho, Yunjo; Jin, Jang Mi; Witt, Matthias; Birdwell, Justin E.; Na, Jeong-Geol; Roh, Nam-Sun; Kim, Sunghwan

    2013-01-01

    Laser desorption ionization (LDI) coupled to Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was used to analyze shale oils. Previous work showed that LDI is a sensitive ionization technique for assessing aromatic nitrogen compounds, and oils generated from Green River Formation oil shales are well-documented as being rich in nitrogen. The data presented here demonstrate that LDI is effective in ionizing high-double-bond-equivalent (DBE) compounds and, therefore, is a suitable method for characterizing compounds with condensed structures. Additionally, LDI generates radical cations and protonated ions concurrently, the distribution of which depends upon the molecular structures and elemental compositions, and the basicity of compounds is closely related to the generation of protonated ions. This study demonstrates that LDI FT-ICR MS is an effective ionization technique for use in the study of shale oils at the molecular level. To the best of our knowledge, this is the first time that LDI FT-ICR MS has been applied to shale oils.

  9. Nonuniform fast Fourier transform method for numerical diffraction simulation on tilted planes.

    Science.gov (United States)

    Xiao, Yu; Tang, Xiahui; Qin, Yingxiong; Peng, Hao; Wang, Wei; Zhong, Lijing

    2016-10-01

    The method, based on the rotation of the angular spectrum in the frequency domain, is generally used for the diffraction simulation between the tilted planes. Due to the rotation of the angular spectrum, the interval between the sampling points in the Fourier domain is not even. For the conventional fast Fourier transform (FFT)-based methods, a spectrum interpolation is needed to get the approximate sampling value on the equidistant sampling points. However, due to the numerical error caused by the spectrum interpolation, the calculation accuracy degrades very quickly as the rotation angle increases. Here, the diffraction propagation between the tilted planes is transformed into a problem about the discrete Fourier transform on the uneven sampling points, which can be evaluated effectively and precisely through the nonuniform fast Fourier transform method (NUFFT). The most important advantage of this method is that the conventional spectrum interpolation is avoided and the high calculation accuracy can be guaranteed for different rotation angles, even when the rotation angle is close to π/2. Also, its calculation efficiency is comparable with that of the conventional FFT-based methods. Numerical examples as well as a discussion about the calculation accuracy and the sampling method are presented.

  10. Introduction to Body Composition Assessment Using the Deuterium Dilution Technique with Analysis of Saliva Samples by Fourier Transform Infrared Spectrometry (Spanish Edition)

    International Nuclear Information System (INIS)

    2013-01-01

    For many years, the IAEA has fostered the more widespread use of stable isotope techniques to assess body composition in different population groups to address priority areas in public health nutrition in Member States. The objective is to support national and regional nutrition projects through both the IAEA's technical cooperation programme and its coordinated research projects. In particular, during the last few years, the increased access to analyses of deuterium enrichment by Fourier transform infrared (FTIR) spectrometry has increased the application of this technique in Africa, Asia and Latin America. This publication was developed by an international group of experts to provide practical, hands-on guidance in the use of this technique in settings where the analysis of deuterium enrichment in saliva samples will be made by FTIR. It is targeted at new users of this technique, for example nutritionists, analytical chemists and other professionals. More detailed information on the theoretical background and the practical application of state of the art methodologies to monitor changes in body composition can be found in an IAEA publication entitled Assessment of Body Composition and Total Energy Expenditure in Humans by Stable Isotope Techniques (IAEA Human Health Series No. 3)

  11. Introduction to Body Composition Assessment Using the Deuterium Dilution Technique with Analysis of Saliva Samples by Fourier Transform Infrared Spectrometry (French Edition)

    International Nuclear Information System (INIS)

    2013-01-01

    For many years, the IAEA has fostered the more widespread use of stable isotope techniques to assess body composition in different population groups to address priority areas in public health nutrition in Member States. The objective is to support national and regional nutrition projects through both the IAEA's technical cooperation programme and its coordinated research projects. In particular, during the last few years, the increased access to analyses of deuterium enrichment by Fourier transform infrared (FTIR) spectrometry has increased the application of this technique in Africa, Asia and Latin America. This publication was developed by an international group of experts to provide practical, hands-on guidance in the use of this technique in settings where the analysis of deuterium enrichment in saliva samples will be made by FTIR. It is targeted at new users of this technique, for example nutritionists, analytical chemists and other professionals. More detailed information on the theoretical background and the practical application of state of the art methodologies to monitor changes in body composition can be found in an IAEA publication entitled Assessment of Body Composition and Total Energy Expenditure in Humans by Stable Isotope Techniques (IAEA Human Health Series No. 3)

  12. A fourier transform quality measure for iris images

    CSIR Research Space (South Africa)

    Makinana, S

    2014-08-01

    Full Text Available to ensure that good quality images are selected for feature extraction, in order to improve iris recognition system. In addition, this research proposes a measure of iris image quality using a Fourier Transform. The experimental results demonstrate...

  13. Discrete Fourier Transform in a Complex Vector Space

    Science.gov (United States)

    Dean, Bruce H. (Inventor)

    2015-01-01

    An image-based phase retrieval technique has been developed that can be used on board a space based iterative transformation system. Image-based wavefront sensing is computationally demanding due to the floating-point nature of the process. The discrete Fourier transform (DFT) calculation is presented in "diagonal" form. By diagonal we mean that a transformation of basis is introduced by an application of the similarity transform of linear algebra. The current method exploits the diagonal structure of the DFT in a special way, particularly when parts of the calculation do not have to be repeated at each iteration to converge to an acceptable solution in order to focus an image.

  14. Metabolomic profiling using Orbitrap Fourier transform mass spectrometry with hydrophilic interaction chromatography : a method with wide applicability to analysis of biomolecules

    NARCIS (Netherlands)

    Kamleh, A.; Barrett, M. P.; Wildridge, D.; Burchmore, R. J. S.; Scheltema, R. A.; Watson, D. G.

    It was shown that coupling hydrophilic interaction chromatography (HILIC) to Orbitrap Fourier transform mass spectrometery (FT-MS) provided an excellent tool for metabolic profiling, principally due to rapid elution of lipids in advance of most metabolites entering the mass spectrometer. We used in

  15. Static harmonization of dynamically harmonized Fourier transform ion cyclotron resonance cell.

    Science.gov (United States)

    Zhdanova, Ekaterina; Kostyukevich, Yury; Nikolaev, Eugene

    2017-08-01

    Static harmonization in the Fourier transform ion cyclotron resonance cell improves the resolving power of the cell and prevents dephasing of the ion cloud in the case of any trajectory of the charged particle, not necessarily axisymmetric cyclotron (as opposed to dynamic harmonization). We reveal that the Fourier transform ion cyclotron resonance cell with dynamic harmonization (paracell) is proved to be statically harmonized. The volume of the statically harmonized potential distribution increases with an increase in the number of trap segments.

  16. Properly used ''aliasing'' can give better resolution from fewer points in Fourier transform spectroscopy

    Science.gov (United States)

    D'Astous, Y.; Blanchard, M.

    1982-05-01

    In the past years, the Journal has published a number of articles1-5 devoted to the introduction of Fourier transform spectroscopy in the undergraduate labs. In most papers, the proposed experimental setup consists of a Michelson interferometer, a light source, a light detector, and a chart recorder. The student uses this setup to record an interferogram which is then Fourier transformed to obtain the spectrogram of the light source. Although attempts have been made to ease the task of performing the required Fourier transform,6 the use of computers and Cooley-Tukey's fast Fourier transform (FFT) algorithm7 is by far the simplest method to use. However, to be able to use FFT, one has to get a number of samples of the interferogram, a tedious job which should be kept to a minimum. (AIP)

  17. Dual beam encoded extended fractional Fourier transform security ...

    Indian Academy of Sciences (India)

    This paper describes a simple method for making dual beam encoded extended fractional Fourier transform (EFRT) security holograms. The hologram possesses different stages of encoding so that security features are concealed and remain invisible to the counterfeiter. These concealed and encoded anticounterfeit ...

  18. Fourier transform infrared spectrometery: an undergraduate experiment

    International Nuclear Information System (INIS)

    Lerner, L

    2016-01-01

    Simple apparatus is developed, providing undergraduate students with a solid understanding of Fourier transform (FT) infrared (IR) spectroscopy in a hands on experiment. Apart from its application to measuring the mid-IR spectra of organic molecules, the experiment introduces several techniques with wide applicability in physics, including interferometry, the FT, digital data analysis, and control theory. (paper)

  19. Fourier transforms on a semisimple symmetric space

    NARCIS (Netherlands)

    Ban, E.P. van den; Schlichtkrull, H.

    1994-01-01

    Let G=H be a semisimple symmetric space, that is, G is a connected semisimple real Lie group with an involution ?, and H is an open subgroup of the group of xed points for ? in G. The main purpose of this paper is to study an explicit Fourier transform on G=H. In terms of general representation

  20. Fourier transforms on a semisimple symmetric space

    NARCIS (Netherlands)

    Ban, E.P. van den; Carmona, J.; Delorme, P.

    1997-01-01

    Let G=H be a semisimple symmetric space, that is, G is a connected semisimple real Lie group with an involution ?, and H is an open subgroup of the group of xed points for ? in G. The main purpose of this paper is to study an explicit Fourier transform on G=H. In terms of general representation

  1. The gridding method for image reconstruction by Fourier transformation

    International Nuclear Information System (INIS)

    Schomberg, H.; Timmer, J.

    1995-01-01

    This paper explores a computational method for reconstructing an n-dimensional signal f from a sampled version of its Fourier transform f. The method involves a window function w and proceeds in three steps. First, the convolution g = w * f is computed numerically on a Cartesian grid, using the available samples of f. Then, g = wf is computed via the inverse discrete Fourier transform, and finally f is obtained as g/w. Due to the smoothing effect of the convolution, evaluating w * f is much less error prone than merely interpolating f. The method was originally devised for image reconstruction in radio astronomy, but is actually applicable to a broad range of reconstructive imaging methods, including magnetic resonance imaging and computed tomography. In particular, it provides a fast and accurate alternative to the filtered backprojection. The basic method has several variants with other applications, such as the equidistant resampling of arbitrarily sampled signals or the fast computation of the Radon (Hough) transform

  2. Hyperfine structure measurements of neutral iodine atom (127I) using Fourier Transform Spectrometry

    Science.gov (United States)

    Ashok, Chilukoti; Vishwakarma, S. R.; Bhatt, Himal; Ankush, B. K.; Deo, M. N.

    2018-01-01

    We report the hyperfine Structure (hfs) splitting observations of neutral iodine atom (II) in the 6000 - 10,000 cm-1 near infrared spectral region. The measurements were carried out using a high-resolution Fourier Transform Spectrometer (FTS), where an electrodeless discharge lamp (EDL), excited using microwaves, was employed as the light source and InGaAs as the light detector. A specially designed setup was used to lower the plasma temperature of the medium so as to reduce the Doppler width and consequently to increase the spectral resolution of hfs components. A total of 183 lines with hfs splitting have been observed, out of which hfs in 53 spectral lines are reported for the first time. On the basis of hfs analysis, we derived the magnetic dipole and electric quadrupole coupling constants, A and B respectively for 30 even and 30 odd energy levels and are compared with the values available in the literature. New hfs values for 5 even and 4 odd levels are also reported here for the first time.

  3. [A study of Boletus bicolor from different areas using Fourier transform infrared spectrometry].

    Science.gov (United States)

    Zhou, Zai-Jin; Liu, Gang; Ren, Xian-Pei

    2010-04-01

    It is hard to differentiate the same species of wild growing mushrooms from different areas by macromorphological features. In this paper, Fourier transform infrared (FTIR) spectroscopy combined with principal component analysis was used to identify 58 samples of boletus bicolor from five different areas. Based on the fingerprint infrared spectrum of boletus bicolor samples, principal component analysis was conducted on 58 boletus bicolor spectra in the range of 1 350-750 cm(-1) using the statistical software SPSS 13.0. According to the result, the accumulated contributing ratio of the first three principal components accounts for 88.87%. They included almost all the information of samples. The two-dimensional projection plot using first and second principal component is a satisfactory clustering effect for the classification and discrimination of boletus bicolor. All boletus bicolor samples were divided into five groups with a classification accuracy of 98.3%. The study demonstrated that wild growing boletus bicolor at species level from different areas can be identified by FTIR spectra combined with principal components analysis.

  4. Fourier transform infrared spectrophotometry and X-ray powder ...

    African Journals Online (AJOL)

    This study aimed at demonstrating complementary roles offered by both Fourier transform infrared (FTIR) spectrophotometry and x-ray powder diffraction (XRPD) techniques in characterizing clay size fraction of kaolins. The clay size fraction of kaolin samples obtained from Kgwakgwe, Makoro, Lobatse and Serule kaolin ...

  5. Fourier transform infrared (FTIR) spectroscopy for identification of ...

    African Journals Online (AJOL)

    Fourier transform infrared (FTIR) spectroscopy was used in this study to identify and determine spectral features of Chlorella vulgaris Beijerinck 1890 and Scenedesmus obliquus (Turpin) Kützing 1833. Two cultures were grown in a chemically-defined media under photoautotrophic culture conditions isolated from eutrophic ...

  6. S-duality as Fourier transform for arbitrary ϵ1, ϵ2

    International Nuclear Information System (INIS)

    N Nemkov

    2014-01-01

    The Alday–Gaiotto–Tachikawa relations reduce S-duality to the modular transformations of conformal blocks. It was recently conjectured that, for the four-point conformal block, the modular transform up to the non-perturbative contributions can be written in the form of the ordinary Fourier transform when β ≡ −ϵ 1 /ϵ 2 = 1. Here I extend this conjecture to general values of ϵ 1 , ϵ 2 . Namely, I argue that, for a properly normalized four-point conformal block the S-duality is perturbatively given by the Fourier transform for arbitrary values of the deformation parameters ϵ 1 , ϵ 2 . The conjecture is based on explicit perturbative computations in the first few orders of the string coupling constant g 2 ≡ −ϵ 1 ϵ 2 and hypermultiplet masses. (paper)

  7. The Pegg–Barnett phase operator and the discrete Fourier transform

    International Nuclear Information System (INIS)

    Perez-Leija, Armando; Szameit, Alexander; Andrade-Morales, Luis A; Soto-Eguibar, Francisco; Moya-Cessa, Héctor M

    2016-01-01

    In quantum mechanics the position and momentum operators are related to each other via the Fourier transform. In the same way, here we show that the so-called Pegg–Barnett phase operator can be obtained by the application of the discrete Fourier transform to the number operators defined in a finite-dimensional Hilbert space. Furthermore, we show that the structure of the London–Susskind–Glogower phase operator, whose natural logarithm gives rise to the Pegg–Barnett phase operator, is contained in the Hamiltonian of circular waveguide arrays. Our results may find applications in the development of new finite-dimensional photonic systems with interesting phase-dependent properties. (invited comment)

  8. Fourier Transform Spectrometer System

    Science.gov (United States)

    Campbell, Joel F. (Inventor)

    2014-01-01

    A Fourier transform spectrometer (FTS) data acquisition system includes an FTS spectrometer that receives a spectral signal and a laser signal. The system further includes a wideband detector, which is in communication with the FTS spectrometer and receives the spectral signal and laser signal from the FTS spectrometer. The wideband detector produces a composite signal comprising the laser signal and the spectral signal. The system further comprises a converter in communication with the wideband detector to receive and digitize the composite signal. The system further includes a signal processing unit that receives the composite signal from the converter. The signal processing unit further filters the laser signal and the spectral signal from the composite signal and demodulates the laser signal, to produce velocity corrected spectral data.

  9. The su(2)α Hahn oscillator and a discrete Fourier-Hahn transform

    International Nuclear Information System (INIS)

    Jafarov, E I; Stoilova, N I; Van der Jeugt, J

    2011-01-01

    We define the quadratic algebra su(2) α which is a one-parameter deformation of the Lie algebra su(2) extended by a parity operator. The odd-dimensional representations of su(2) (with representation label j, a positive integer) can be extended to representations of su(2) α . We investigate a model of the finite one-dimensional harmonic oscillator based upon this algebra su(2) α . It turns out that in this model the spectrum of the position and momentum operator can be computed explicitly, and that the corresponding (discrete) wavefunctions can be determined in terms of Hahn polynomials. The operation mapping position wavefunctions into momentum wavefunctions is studied, and this so-called discrete Fourier-Hahn transform is computed explicitly. The matrix of this discrete Fourier-Hahn transform has many interesting properties, similar to those of the traditional discrete Fourier transform. (paper)

  10. [Continuum based fast Fourier transform processing of infrared spectrum].

    Science.gov (United States)

    Liu, Qing-Jie; Lin, Qi-Zhong; Wang, Qin-Jun; Li, Hui; Li, Shuai

    2009-12-01

    To recognize ground objects with infrared spectrum, high frequency noise removing is one of the most important phases in spectrum feature analysis and extraction. A new method for infrared spectrum preprocessing was given combining spectrum continuum processing and Fast Fourier Transform (CFFT). Continuum was firstly removed from the noise polluted infrared spectrum to standardize hyper-spectra. Then the spectrum was transformed into frequency domain (FD) with fast Fourier transform (FFT), separating noise information from target information After noise eliminating from useful information with a low-pass filter, the filtered FD spectrum was transformed into time domain (TD) with fast Fourier inverse transform. Finally the continuum was recovered to the spectrum, and the filtered infrared spectrum was achieved. Experiment was performed for chlorite spectrum in USGS polluted with two kinds of simulated white noise to validate the filtering ability of CFFT by contrast with cubic function of five point (CFFP) in time domain and traditional FFT in frequency domain. A circle of CFFP has limited filtering effect, so it should work much with more circles and consume more time to achieve better filtering result. As for conventional FFT, Gibbs phenomenon has great effect on preprocessing result at edge bands because of special character of rock or mineral spectra, while works well at middle bands. Mean squared error of CFFT is 0. 000 012 336 with cut-off frequency of 150, while that of FFT and CFFP is 0. 000 061 074 with cut-off frequency of 150 and 0.000 022 963 with 150 working circles respectively. Besides the filtering result of CFFT can be improved by adjusting the filter cut-off frequency, and has little effect on working time. The CFFT method overcomes the Gibbs problem of FFT in spectrum filtering, and can be more convenient, dependable, and effective than traditional TD filter methods.

  11. Quantum Fourier Transform Over Galois Rings

    OpenAIRE

    Zhang, Yong

    2009-01-01

    Galois rings are regarded as "building blocks" of a finite commutative ring with identity. There have been many papers on classical error correction codes over Galois rings published. As an important warm-up before exploring quantum algorithms and quantum error correction codes over Galois rings, we study the quantum Fourier transform (QFT) over Galois rings and prove it can be efficiently preformed on a quantum computer. The properties of the QFT over Galois rings lead to the quantum algorit...

  12. Fourier Transform Methods. Chapter 4

    Science.gov (United States)

    Kaplan, Simon G.; Quijada, Manuel A.

    2015-01-01

    This chapter describes the use of Fourier transform spectrometers (FTS) for accurate spectrophotometry over a wide spectral range. After a brief exposition of the basic concepts of FTS operation, we discuss instrument designs and their advantages and disadvantages relative to dispersive spectrometers. We then examine how common sources of error in spectrophotometry manifest themselves when using an FTS and ways to reduce the magnitude of these errors. Examples are given of applications to both basic and derived spectrophotometric quantities. Finally, we give recommendations for choosing the right instrument for a specific application, and how to ensure the accuracy of the measurement results..

  13. Application of the fractional Fourier transform to image reconstruction in MRI.

    Science.gov (United States)

    Parot, Vicente; Sing-Long, Carlos; Lizama, Carlos; Tejos, Cristian; Uribe, Sergio; Irarrazaval, Pablo

    2012-07-01

    The classic paradigm for MRI requires a homogeneous B(0) field in combination with linear encoding gradients. Distortions are produced when the B(0) is not homogeneous, and several postprocessing techniques have been developed to correct them. Field homogeneity is difficult to achieve, particularly for short-bore magnets and higher B(0) fields. Nonlinear magnetic components can also arise from concomitant fields, particularly in low-field imaging, or intentionally used for nonlinear encoding. In any of these situations, the second-order component is key, because it constitutes the first step to approximate higher-order fields. We propose to use the fractional Fourier transform for analyzing and reconstructing the object's magnetization under the presence of quadratic fields. The fractional fourier transform provides a precise theoretical framework for this. We show how it can be used for reconstruction and for gaining a better understanding of the quadratic field-induced distortions, including examples of reconstruction for simulated and in vivo data. The obtained images have improved quality compared with standard Fourier reconstructions. The fractional fourier transform opens a new paradigm for understanding the MR signal generated by an object under a quadratic main field or nonlinear encoding. Copyright © 2011 Wiley Periodicals, Inc.

  14. Time-Domain Optical Fourier Transformation for OTDM-DWDM and DWDM-OTDM Conversion

    DEFF Research Database (Denmark)

    Mulvad, Hans Christian Hansen; Palushani, Evarist; Galili, Michael

    2011-01-01

    Applications of time-domain optical Fourier transformation (OFT) in ultra-high-speed optical time-division multiplexed systems (OTDM) are reviewed, with emphasis on the recent demonstrations of OFT-based conversion between the OTDM and DWDM formats.......Applications of time-domain optical Fourier transformation (OFT) in ultra-high-speed optical time-division multiplexed systems (OTDM) are reviewed, with emphasis on the recent demonstrations of OFT-based conversion between the OTDM and DWDM formats....

  15. Ultrafast and versatile spectroscopy by temporal Fourier transform

    Science.gov (United States)

    Zhang, Chi; Wei, Xiaoming; Marhic, Michel E.; Wong, Kenneth K. Y.

    2014-06-01

    One of the most remarkable and useful properties of a spatially converging lens system is its inherent ability to perform the Fourier transform; the same applies for the time-lens system. At the back focal plane of the time-lens, the spectral information can be instantaneously obtained in the time axis. By implementing temporal Fourier transform for spectroscopy applications, this time-lens-based architecture can provide orders of magnitude improvement over the state-of-art spatial-dispersion-based spectroscopy in terms of the frame rate. On the other hand, in addition to the single-lens structure, the multi-lens structures (e.g. telescope or wide-angle scope) will provide very versatile operating conditions. Leveraging the merit of instantaneous response, as well as the flexible lens structure, here we present a 100-MHz frame rate spectroscopy system - the parametric spectro-temporal analyzer (PASTA), which achieves 17 times zoom in/out ratio for different observation ranges.

  16. Fourier transform digital holographic adaptive optics imaging system

    Science.gov (United States)

    Liu, Changgeng; Yu, Xiao; Kim, Myung K.

    2013-01-01

    A Fourier transform digital holographic adaptive optics imaging system and its basic principles are proposed. The CCD is put at the exact Fourier transform plane of the pupil of the eye lens. The spherical curvature introduced by the optics except the eye lens itself is eliminated. The CCD is also at image plane of the target. The point-spread function of the system is directly recorded, making it easier to determine the correct guide-star hologram. Also, the light signal will be stronger at the CCD, especially for phase-aberration sensing. Numerical propagation is avoided. The sensor aperture has nothing to do with the resolution and the possibility of using low coherence or incoherent illumination is opened. The system becomes more efficient and flexible. Although it is intended for ophthalmic use, it also shows potential application in microscopy. The robustness and feasibility of this compact system are demonstrated by simulations and experiments using scattering objects. PMID:23262541

  17. On the finite Fourier transforms of functions with infinite discontinuities

    Directory of Open Access Journals (Sweden)

    Branko Saric

    2002-01-01

    Full Text Available The introductory part of the paper is provided to give a brief review of the stability theory of a matrix pencil for discrete linear time-invariant singular control systems, based on the causal relationship between Jordan's theorem from the theory of Fourier series and Laurent's theorem from the calculus of residues. The main part is concerned with the theory of the integral transforms, which has proved to be a powerful tool in the control systems theory. On the basis of a newly defined notion of the total value of improper integrals, throughout the main part of the paper, an attempt has been made to present the global theory of the integral transforms, which are slightly more general with respect to the Laplace and Fourier transforms. The paper ends with examples by which the results of the theory are verified.

  18. The Fourier transform for certain hyperkähler fourfolds

    CERN Document Server

    Shen, Mingmin

    2016-01-01

    Using a codimension-1 algebraic cycle obtained from the Poincaré line bundle, Beauville defined the Fourier transform on the Chow groups of an abelian variety A and showed that the Fourier transform induces a decomposition of the Chow ring \\mathrm{CH}^*(A). By using a codimension-2 algebraic cycle representing the Beauvilleâe"Bogomolov class, the authors give evidence for the existence of a similar decomposition for the Chow ring of Hyperkähler varieties deformation equivalent to the Hilbert scheme of length-2 subschemes on a K3 surface. They indeed establish the existence of such a decomposition for the Hilbert scheme of length-2 subschemes on a K3 surface and for the variety of lines on a very general cubic fourfold.

  19. Designing Fresnel microlenses for focusing astigmatic multi-Gaussian beams by using fractional order Fourier transforms

    International Nuclear Information System (INIS)

    Patino, A; Durand, P-E; Fogret, E; Pellat-Finet, P

    2011-01-01

    According to a scalar theory of diffraction, light propagation can be expressed by two-dimensional fractional order Fourier transforms. Since the fractional Fourier transform of a chirp function is a Dirac distribution, focusing a light beam is optically achieved by using a diffractive screen whose transmission function is a two-dimensional chirp function. This property is applied to designing Fresnel microlenses, and the orders of the involved Fourier fractional transforms depend on diffraction distances as well as on emitter and receiver radii of curvature. If the emitter is astigmatic (with two principal radii of curvature), the diffraction phenomenon involves two one-dimensional fractional Fourier transforms whose orders are different. This degree of freedom allows us to design microlenses that can focus astigmatic Gaussian beams, as produced by a line-shaped laser diode source.

  20. On the physical relevance of the discrete Fourier transform

    CSIR Research Space (South Africa)

    Greben, JM

    1991-11-01

    Full Text Available This paper originated from the author's dissatisfaction with the way the discrete Fourier transform is usually presented in the literature. Although mathematically correct, the physical meaning of the common representation is unsatisfactory...

  1. A low noise single-transistor transimpedance preamplifier for Fourier-transform mass spectrometry using a T feedback network.

    Science.gov (United States)

    Lin, Tzu-Yung; Green, Roger J; O'Connor, Peter B

    2012-09-01

    A novel single-transistor transimpedance preamplifier has been introduced for improving performance in Fourier-transform ion cyclotron resonance (FT-ICR) mass spectrometry. A low noise junction field-effect transistor (JFET), BF862, is used as the main amplification stage of this trans-impedance preamplifier, and a T-shaped feedback network is introduced as both the feedback and the gate biasing solutions. The T feedback network has been studied using an operational amplifier (Op Amp), AD8099. Such a feedback system allows ~100-fold less feedback resistance at a given transimpedance, hence preserving bandwidth, which is beneficial to applications demanding high gain. The single-transistor preamplifier yields a tested transimpedance of ~10(4) Ω (80 dBΩ) in the frequency range between 1 kHz and 1 MHz (mass-to-charge ratio, m/z, of around 180-180k for a 12-T FT-ICR system), with a low power consumption of ~6 mW, which implies that this preamplifier is well suited to a 12-T FT-ICR mass spectrometer. In trading noise performance for higher trans-impedance, an alternative preamplifier design, an AD8099 preamplifier with the T feedback network, has also been studied with a capability of ~10(6) Ω (120 dBΩ) transimpedance in the same frequency range. The resistive components in the T feedback network reported here can be replaced by complex impedances, which allows adaptation of this feedback system to other frequency, transimpedance, and noise characteristics for applications not only in other mass spectrometers, such as Orbitrap, time-of-flight (TOF), and ion trap systems, but also in other charge/current detecting systems such as spectroscopy systems, microscopy systems, optical communication systems, or charge-coupled devices (CCDs).

  2. SPICA/SAFARI fourier transform spectrometer mechanism evolutionary design

    NARCIS (Netherlands)

    Dool, T.C. van den; Kruizinga, B.; Braam, B.C.; Hamelinck, R.F.M.M.; Loix, N.; Loon, D. van; Dams, J.

    2012-01-01

    TNO, together with its partners, have designed a cryogenic scanning mechanism for use in the SAFARI Fourier Transform Spectrometer (FTS) on board of the SPICA mission. SPICA is one of the M-class missions competing to be launched in ESA's Cosmic Vision Programme in 2022. JAXA leads the development

  3. Solution of two-dimensional neutron diffusion equation for triangular region by finite Fourier transformation

    International Nuclear Information System (INIS)

    Kobayashi, Keisuke; Ishibashi, Hideo

    1978-01-01

    A two-dimensional neutron diffusion equation for a triangular region is shown to be solved by the finite Fourier transformation. An application of the Fourier transformation to the diffusion equation for triangular region yields equations whose unknowns are the expansion coefficients of the neutron flux and current in Fourier series or Legendre polynomials expansions only at the region boundary. Some numerical calculations have revealed that the present technique gives accurate results. It is shown also that the solution using the expansion in Legendre polynomials converges with relatively few terms even if the solution in Fourier series exhibits the Gibbs' phenomenon. (auth.)

  4. Solution of two-dimensional diffusion equation for hexagonal cells by the finite Fourier transformation

    International Nuclear Information System (INIS)

    Kobayashi, Keisuke

    1975-01-01

    A method of solution is presented for a monoenergetic diffusion equation in two-dimensional hexagonal cells by a finite Fourier transformation. Up to the present, the solution by the finite Fourier transformation has been developed for x-y, r-z and x-y-z geometries, and the flux and current at the boundary are obtained in terms of Fourier series. It is shown here that the method can be applied to hexagonal cells and the expansion of boundary values in a Legendre polynomials gives numerically a higher accuracy than is obtained by a Fourier series. (orig.) [de

  5. Multi-Beam Radio Frequency (RF) Aperture Arrays Using Multiplierless Approximate Fast Fourier Transform (FFT)

    Science.gov (United States)

    2017-08-01

    Fourier transform, discrete Fourier transform, digital array processing , antenna beamformers 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF...125 3.7 Simulation of 2-D Beams Cross Sections .................................................................... 125 3.7.1 8...unlimited. List of Figures Figure Page Figure 1: N-beam Array Processing System using a Linear Array

  6. Building a symbolic computer algebra toolbox to compute 2D Fourier transforms in polar coordinates.

    Science.gov (United States)

    Dovlo, Edem; Baddour, Natalie

    2015-01-01

    The development of a symbolic computer algebra toolbox for the computation of two dimensional (2D) Fourier transforms in polar coordinates is presented. Multidimensional Fourier transforms are widely used in image processing, tomographic reconstructions and in fact any application that requires a multidimensional convolution. By examining a function in the frequency domain, additional information and insights may be obtained. The advantages of our method include: •The implementation of the 2D Fourier transform in polar coordinates within the toolbox via the combination of two significantly simpler transforms.•The modular approach along with the idea of lookup tables implemented help avoid the issue of indeterminate results which may occur when attempting to directly evaluate the transform.•The concept also helps prevent unnecessary computation of already known transforms thereby saving memory and processing time.

  7. Generalized formulation of an encryption system based on a joint transform correlator and fractional Fourier transform

    International Nuclear Information System (INIS)

    Vilardy, Juan M; Millán, María S; Pérez-Cabré, Elisabet; Torres, Yezid

    2014-01-01

    We propose a generalization of the encryption system based on double random phase encoding (DRPE) and a joint transform correlator (JTC), from the Fourier domain to the fractional Fourier domain (FrFD) by using the fractional Fourier operators, such as the fractional Fourier transform (FrFT), fractional traslation, fractional convolution and fractional correlation. Image encryption systems based on a JTC architecture in the FrFD usually produce low quality decrypted images. In this work, we present two approaches to improve the quality of the decrypted images, which are based on nonlinear processing applied to the encrypted function (that contains the joint fractional power spectrum, JFPS) and the nonzero-order JTC in the FrFD. When the two approaches are combined, the quality of the decrypted image is higher. In addition to the advantages introduced by the implementation of the DRPE using a JTC, we demonstrate that the proposed encryption system in the FrFD preserves the shift-invariance property of the JTC-based encryption system in the Fourier domain, with respect to the lateral displacement of both the key random mask in the decryption process and the retrieval of the primary image. The feasibility of this encryption system is verified and analyzed by computer simulations. (paper)

  8. The RC Circuit: An Approach with Fourier Transforms

    Indian Academy of Sciences (India)

    The RC Circuit: An Approach with Fourier Transforms. Classroom Volume 21 Issue 11 November 2016 pp 1029-1042 ... But a lot of things, (including the complex impedanceitself, and some insight into complex analysis) can be understoodbetter if we use the FT approach to solve the differentialequations that come up in ...

  9. Novel Polynomial Basis with Fast Fourier Transform and Its Application to Reed-Solomon Erasure Codes

    KAUST Repository

    Lin, Sian-Jheng; Al-Naffouri, Tareq Y.; Han, Yunghsiang S.; Chung, Wei-Ho

    2016-01-01

    In this paper, we present a fast Fourier transform (FFT) algorithm over extension binary fields, where the polynomial is represented in a non-standard basis. The proposed Fourier-like transform requires O(h lg(h)) field operations, where h

  10. Matrix-Vector Based Fast Fourier Transformations on SDR Architectures

    Directory of Open Access Journals (Sweden)

    Y. He

    2008-05-01

    Full Text Available Today Discrete Fourier Transforms (DFTs are applied in various radio standards based on OFDM (Orthogonal Frequency Division Multiplex. It is important to gain a fast computational speed for the DFT, which is usually achieved by using specialized Fast Fourier Transform (FFT engines. However, in face of the Software Defined Radio (SDR development, more general (parallel processor architectures are often desirable, which are not tailored to FFT computations. Therefore, alternative approaches are required to reduce the complexity of the DFT. Starting from a matrix-vector based description of the FFT idea, we will present different factorizations of the DFT matrix, which allow a reduction of the complexity that lies between the original DFT and the minimum FFT complexity. The computational complexities of these factorizations and their suitability for implementation on different processor architectures are investigated.

  11. Deficiencies of the cryptography based on multiple-parameter fractional Fourier transform.

    Science.gov (United States)

    Ran, Qiwen; Zhang, Haiying; Zhang, Jin; Tan, Liying; Ma, Jing

    2009-06-01

    Methods of image encryption based on fractional Fourier transform have an incipient flaw in security. We show that the schemes have the deficiency that one group of encryption keys has many groups of keys to decrypt the encrypted image correctly for several reasons. In some schemes, many factors result in the deficiencies, such as the encryption scheme based on multiple-parameter fractional Fourier transform [Opt. Lett.33, 581 (2008)]. A modified method is proposed to avoid all the deficiencies. Security and reliability are greatly improved without increasing the complexity of the encryption process. (c) 2009 Optical Society of America.

  12. Fourier transform wavefront control with adaptive prediction of the atmosphere.

    Science.gov (United States)

    Poyneer, Lisa A; Macintosh, Bruce A; Véran, Jean-Pierre

    2007-09-01

    Predictive Fourier control is a temporal power spectral density-based adaptive method for adaptive optics that predicts the atmosphere under the assumption of frozen flow. The predictive controller is based on Kalman filtering and a Fourier decomposition of atmospheric turbulence using the Fourier transform reconstructor. It provides a stable way to compensate for arbitrary numbers of atmospheric layers. For each Fourier mode, efficient and accurate algorithms estimate the necessary atmospheric parameters from closed-loop telemetry and determine the predictive filter, adjusting as conditions change. This prediction improves atmospheric rejection, leading to significant improvements in system performance. For a 48x48 actuator system operating at 2 kHz, five-layer prediction for all modes is achievable in under 2x10(9) floating-point operations/s.

  13. Fourier-transforming with quantum annealers

    Directory of Open Access Journals (Sweden)

    Itay eHen

    2014-07-01

    Full Text Available We introduce a set of quantum adiabatic evolutions that we argue may be used as `building blocks', or subroutines, in the onstruction of an adiabatic algorithm that executes Quantum Fourier Transform (QFT with the same complexity and resources as its gate-model counterpart. One implication of the above construction is the theoretical feasibility of implementing Shor's algorithm for integer factorization in an optimal manner, and any other algorithm that makes use of QFT, on quantum annealing devices. We discuss the possible advantages, as well as the limitations, of the proposed approach as well as its relation to traditional adiabatic quantum computation.

  14. Transformation of a Free-Wilson matrix into Fourier coefficients

    Czech Academy of Sciences Publication Activity Database

    Holík, M.; Halámek, Josef

    2002-01-01

    Roč. 20, - (2002), s. 422 - 428 ISSN 0931-8771 Institutional research plan: CEZ:AV0Z2065902 Keywords : Free-Wilson matrix * Fourier transform * multivariate regression Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.558, year: 2002

  15. From the rectangular to the quincunx Gabor lattice via fractional Fourier transformation

    NARCIS (Netherlands)

    Bastiaans, M.J.; Leest, van A.J.

    1998-01-01

    Transformations of Gabor lattices have been associated with operations on the window functions that arise in Gabor theory. In particular it has been shown that transformation from a rectangular to a quincunx lattice can be associated with fractional Fourier transformation. Since a Gaussian function,

  16. Non-stationary component extraction in noisy multicomponent signal using polynomial chirping Fourier transform.

    Science.gov (United States)

    Lu, Wenlong; Xie, Junwei; Wang, Heming; Sheng, Chuan

    2016-01-01

    Inspired by track-before-detection technology in radar, a novel time-frequency transform, namely polynomial chirping Fourier transform (PCFT), is exploited to extract components from noisy multicomponent signal. The PCFT combines advantages of Fourier transform and polynomial chirplet transform to accumulate component energy along a polynomial chirping curve in the time-frequency plane. The particle swarm optimization algorithm is employed to search optimal polynomial parameters with which the PCFT will achieve a most concentrated energy ridge in the time-frequency plane for the target component. The component can be well separated in the polynomial chirping Fourier domain with a narrow-band filter and then reconstructed by inverse PCFT. Furthermore, an iterative procedure, involving parameter estimation, PCFT, filtering and recovery, is introduced to extract components from a noisy multicomponent signal successively. The Simulations and experiments show that the proposed method has better performance in component extraction from noisy multicomponent signal as well as provides more time-frequency details about the analyzed signal than conventional methods.

  17. q-Extension of Mehta's eigenvectors of the finite Fourier transform for q, a root of unity

    NARCIS (Netherlands)

    Atakishiyeva, M.K.; Atakishiyev, N.M.; Koornwinder, T.H.

    2009-01-01

    It is shown that the continuous q-Hermite polynomials for q, a root of unity, have simple transformation properties with respect to the classical Fourier transform. This result is then used to construct q-extended eigenvectors of the finite Fourier transform in terms of these polynomials.

  18. Hochauflösende Fourier-Transform-Emissionsspektroskopie

    OpenAIRE

    Uibel, Christian

    2000-01-01

    Mittels hochauflösender Fourier-Transform-Infrarot-Emissionsspektroskopie wurden tiefliegende elektronische Anregungszustände der mittelschweren zweiatomigen Radikale As2, Sb2 und TeF untersucht. Dabei lag das Interesse vor allem bei den Emissionen nicht voll erlaubter Übergänge wie beispielsweise der 3Σ +u →  1Σ +g- bzw. (1u) →  (0+g)-Übergänge bei den Stickstoff-Homologen. Dieses besondere Interesse an der genauen Analyse der 3Σ +u-Zustände liegt in ihrem metastab...

  19. Application of Migration Velocity Using Fourier Transform Approach ...

    African Journals Online (AJOL)

    Application of velocity by Fourier transform to process 3-D unmigrated seismic sections has been carried out in Fabi Field, Niger Delta – Nigeria. Usually, all seismic events (sections) are characterized by spikes or noise (random or coherent), multiples and shear waves so that when a seismic bed is dipping, the apparent ...

  20. FREQUENCY COMPONENT EXTRACTION OF HEARTBEAT CUES WITH SHORT TIME FOURIER TRANSFORM (STFT

    Directory of Open Access Journals (Sweden)

    Sumarna Sumarna

    2017-01-01

      Electro-acoustic human heartbeat detector have been made with the main parts : (a stetoscope (piece chest, (b mic condenser, (c transistor amplifier, and (d cues analysis program with MATLAB. The frequency components that contained in heartbeat. cues have also been extracted with Short Time Fourier Transform (STFT from 9 volunteers. The results of the analysis showed that heart rate appeared in every cue frequency spectrum with their harmony. The steps of the research were including detector instrument design, test and instrument repair, cues heartbeat recording with Sound Forge 10 program and stored in wav file ; cues breaking at the start and the end, and extraction/cues analysis using MATLAB. The MATLAB program included filter (bandpass filter with bandwidth between 0.01 – 110 Hz, cues breaking with hamming window and every part was calculated using Fourier Transform (STFT mechanism and the result were shown in frequency spectrum graph.   Keywords: frequency components extraction, heartbeat cues, Short Time Fourier Transform

  1. Soft x-ray microscope using Fourier transform holography

    International Nuclear Information System (INIS)

    McNulty, I.; Kirz, J.; Jacobsen, C.; Anderson, E.; Howells, M.R.; Rarback, H.

    1989-01-01

    A Fourier transform holographic microscope with an anticipated resolution of better than 100 nm has been built. Extensive testing of the apparatus has begun. Preliminary results include the recording of interference fringes using 3.6 nm x-rays. The microscope employs a charge-coupled device (CCD) detector array of 576 x 384 elements. The system is illuminated by soft x-rays from a high brightness undulator. The reference point source is formed by a Fresnel zone plate with a finest outer zone width of 50 nm. Sufficient temporal coherence for hologram formation is obtained by a spherical grating monochromator. The x-ray hologram intensities at the recording plane are to be collected, digitized and reconstructed by computer. Data acquisition is under CAMAC control, while image display and off-line processing takes place on a VAX graphics workstation. Computational models of Fourier transform hologram synthesis, and reconstruction in the presence of noise, have demonstrated the feasibility of numerical methods in two dimensions, and that three-dimensional information is potentially recoverable. 13 refs., 3 figs

  2. Gas Measurement Using Static Fourier Transform Infrared Spectrometers.

    Science.gov (United States)

    Köhler, Michael H; Schardt, Michael; Rauscher, Markus S; Koch, Alexander W

    2017-11-13

    Online monitoring of gases in industrial processes is an ambitious task due to adverse conditions such as mechanical vibrations and temperature fluctuations. Whereas conventional Fourier transform infrared (FTIR) spectrometers use rather complex optical and mechanical designs to ensure stable operation, static FTIR spectrometers do not require moving parts and thus offer inherent stability at comparatively low costs. Therefore, we present a novel, compact gas measurement system using a static single-mirror Fourier transform spectrometer (sSMFTS). The system works in the mid-infrared range from 650 cm - 1 to 1250 cm - 1 and can be operated with a customized White cell, yielding optical path lengths of up to 120 cm for highly sensitive quantification of gas concentrations. To validate the system, we measure different concentrations of 1,1,1,2-Tetrafluoroethane (R134a) and perform a PLS regression analysis of the acquired infrared spectra. Thereby, the measured absorption spectra show good agreement with reference data. Since the system additionally permits measurement rates of up to 200 Hz and high signal-to-noise ratios, an application in process analysis appears promising.

  3. Fourier transform spectroscopy of six stars

    Energy Technology Data Exchange (ETDEWEB)

    Mendoza V, E E [Universidad Nacional Autonoma de Mexico, Mexico City. Inst. de Astronomia

    1981-01-01

    This paper outlines results from a digital analysis of the Fourier transform spectroscopy of six stars: ..sigma.. Aur, rho Ori, ..cap alpha.. Lyr, zeta Aql and ..cap alpha.. Cyg. Nearly 1200 different spectral lines have been identified in the spectra of these six stars in the wavelength interval 4800-10200 A where the spectra are of very high quality, less than the one per cent level of noise versus signal. ..cap alpha.. Lyr and ..cap alpha.. Cyg show spectral line and profile variations easily seen in their spectra.

  4. Combination of liquid chromatography-Fourier transform ion cyclotron resonance-mass spectrometry with 13C-labeling for chemical assignment of sulfur-containing metabolites in onion bulbs.

    Science.gov (United States)

    Nakabayashi, Ryo; Sawada, Yuji; Yamada, Yutaka; Suzuki, Makoto; Hirai, Masami Yokota; Sakurai, Tetsuya; Saito, Kazuki

    2013-02-05

    Phytochemicals containing heteroatoms (N, O, S, and halogens) often have biological activities that are beneficial to humans. Although targeted profiling methods for such phytochemicals are expected to contribute to rapid chemical assignments, thus making phytochemical genomics and crop breeding much more efficient, there are few profiling methods for the metabolites. Here, as an ultrahigh performance approach, we propose a practical profiling method for S-containing metabolites (S-omics) using onions (Allium cepa) as a representative species and (12)C- and (13)C-based mass spectrometry (MS) and tandem mass spectrometry (MS/MS) analyses by liquid chromatography-Fourier transform ion cyclotron resonance-mass spectrometry (LC-FTICR-MS). Use of the ultrahigh quality data from FTICR-MS enabled simplifying the previous methods to determine specific elemental compositions. MS analysis with a resolution of >250,000 full width at half-maximum and a mass accuracy of ions from other ions on the basis of the natural abundance of (32)S and (34)S and the mass differences among the S isotopes. Comprehensive peak picking using the theoretical mass difference (1.99579 Da) between (32)S-containing monoisotopic ions and their (34)S-substituted counterparts led to the assignment of 67 S-containing monoisotopic ions from the (12)C-based MS spectra, which contained 4693 chromatographic ions. The unambiguous elemental composition of 22 ions was identified through comparative analysis of the (12)C- and (13)C-based MS spectra. Finally, of these, six ions were found to be derived from S-alk(en)ylcysteine sulfoxides and glutathione derivatives. This S-atom-driven approach afforded an efficient chemical assignment of S-containing metabolites, suggesting its potential application for screening not only S but also other heteroatom-containing metabolites in MS-based metabolomics.

  5. Fourier transform zero field NMR and NQR

    International Nuclear Information System (INIS)

    Zax, D.B.

    1985-01-01

    In many systems the chemical shifts measured by traditional high resolution solid state NMR methods are insufficiently sensitive, or the information contained in the dipole-dipole couplings is more important. In these cases, Fourier transform zero field magnetic resonance may make an important contribution. Zero field NMR and NQR is the subject of this thesis. Chapter I presents the quantum mechanical background and notational formalism for what follows. Chapter II gives a brief review of high resolution magnetic resonance methods, with particular emphasis on techniques applicable to dipole-dipole and quadrupolar couplings. Level crossings between spin-1/2 and quadrupolar spins during demagnetization transfer polarization from high to low λ nuclei. This is the basis of very high sensitivity zero field NQR measurements by field cycling. Chapter III provides a formal presentation of the high resolution Fourier transform zero field NMR method. Theoretical signal functions are calculated for common spin systems, and examples of typical spectra are presented. Chapters IV and V review the experimental progress in zero field NMR of dipole-dipole coupled spin-1/2 nuclei and for quadrupolar spin systems. Variations of the simple experiment describe in earlier chapters that use pulsed dc fields are presented in Chapter VI

  6. Application of the fourier and wavelet transforms in noise reduction of the out of the ordinary data

    International Nuclear Information System (INIS)

    Tafreshi, M. A.; Sadeghi, Y.

    2006-01-01

    In this article the noise reduction of the experimental data by the Fourier and the wavelet transforms has been investigated. Using both simulated and experimental data (from the plasma focus facility, Dena), the sensitive features of the application of the Fourier transform are visualized and discussed. Then, the main idea of the wavelet transform and the results of the noise reduction with this transform are presented. Due to this investigation, for the cases such as the current derivative of the Dena facility, where the reliability of the Fourier transform can be doubtful, the wavelet transform can be considered as a more accurate alternative approach

  7. Generalized prolate spheroidal wave functions for optical finite fractional Fourier and linear canonical transforms.

    Science.gov (United States)

    Pei, Soo-Chang; Ding, Jian-Jiun

    2005-03-01

    Prolate spheroidal wave functions (PSWFs) are known to be useful for analyzing the properties of the finite-extension Fourier transform (fi-FT). We extend the theory of PSWFs for the finite-extension fractional Fourier transform, the finite-extension linear canonical transform, and the finite-extension offset linear canonical transform. These finite transforms are more flexible than the fi-FT and can model much more generalized optical systems. We also illustrate how to use the generalized prolate spheroidal functions we derive to analyze the energy-preservation ratio, the self-imaging phenomenon, and the resonance phenomenon of the finite-sized one-stage or multiple-stage optical systems.

  8. Comparison of dialysis and solid-phase extraction for isolation and concentration of dissolved organic matter prior to Fourier transform ion cyclotron resonance mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Tfaily, Malak M.; Cooper, William T. [Florida State University, Department of Chemistry and Biochemistry, Tallahassee, FL (United States); Hodgkins, Suzanne; Chanton, Jeffrey P. [Florida State University, Department of Earth, Ocean and Atmospheric Science, Tallahassee, FL (United States); Podgorski, David C. [Florida State University, Department of Chemistry and Biochemistry, Tallahassee, FL (United States); Florida State University, National High Magnetic Field Laboratory, Tallahassee, FL (United States)

    2012-08-15

    We compare two methods, solid-phase extraction (SPE) and dialysis, commonly used for extraction and concentration of dissolved organic matter (DOM) prior to molecular characterization by electrospray ionization (ESI) and ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry. Spectra of DOM samples from Minnesota and Sweden peatlands that were extracted with styrene divinyl benzene polymer SPE sorbents included ions with formulas that had higher oxygen to carbon (O/C) ratios than spectra of DOM from the same samples after de-salting by dialysis. The SPE method was not very effective in extracting several major classes of DOM compounds that had high ESI efficiencies, including carboxylic acids and organo-sulfur compounds, and that out-competed other less-functionalized compounds (e.g., carbohydrates) for charge in the ESI source. The large abundance of carboxylic acids in the dialysisextracted DOM, likely the result of in situ microbial production, makes it difficult to see other (mainly hydrophilic) compounds with high O/C ratios. Our results indicate that, while dialysis is generally preferable for the isolation of DOM, for samples with high microbial inputs, the use of both isolation methods is recommended for a more accurate molecular representation. (orig.)

  9. Practical aspects of trapped ion mass spectrometry, 5 applications of ion trapping devices

    CERN Document Server

    March, Raymond E

    2009-01-01

    Examines ion/neutral and ion/ion reactions, ion spectroscopy, and the structural characterization of proteins and peptides using quadropole ion trap mass spectrometry, Fourier transform - ion cyclotron resonance (FT-ICR) mass spectrometry, and traveling wave ion mobility mass spectrometry.

  10. 21 Tesla Fourier Transform Ion Cyclotron Resonance Mass Spectrometer Greatly Expands Mass Spectrometry Toolbox

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, Jared B.; Lin, Tzu-Yung; Leach, Franklin E.; Tolmachev, Aleksey V.; Tolić, Nikola; Robinson, Errol W.; Koppenaal, David W.; Paša-Tolić, Ljiljana

    2016-10-12

    We provide the initial performance evaluation of a 21 Tesla Fourier transform ion cyclotron resonance mass spectrometer operating at the Environmental Molecular Sciences Laboratory at Pacific Northwest National Laboratory. The spectrometer constructed for the 21T system employs a commercial dual linear ion trap mass spectrometer coupled to a FTICR spectrometer designed and built in-house. Performance gains from moving to higher magnetic field strength are exemplified by the measurement of peptide isotopic fine structure, complex natural organic matter mixtures, and large proteins. Accurate determination of isotopic fine structure was demonstrated for doubly charged substance P with minimal spectral averaging, and 8,158 molecular formulas assigned to Suwannee River Fulvic Acid standard with RMS error of 10 ppb. We also demonstrated superior performance for intact proteins; namely, broadband isotopic resolution of the entire charge state distribution of apotransferrin (78 kDa) and facile isotopic resolution of monoclonal antibody under a variety of acquisition parameters (e.g. 6 s time-domains with absorption mode processing yielded resolution of approximately 1M at m/z =2,700).

  11. Fourier Transform Spectrometer Controller for Partitioned Architectures

    DEFF Research Database (Denmark)

    Tamas-Selicean, Domitian; Keymeulen, D.; Berisford, D.

    2013-01-01

    The current trend in spacecraft computing is to integrate applications of different criticality levels on the same platform using no separation. This approach increases the complexity of the development, verification and integration processes, with an impact on the whole system life cycle. Resear......, such as avionics and automotive. In this paper we investigate the challenges of developing and the benefits of integrating a scientific instrument, namely a Fourier Transform Spectrometer, in such a partitioned architecture....

  12. Theory of peak coalescence in Fourier transform ion cyclotron resonance mass spectrometry.

    Science.gov (United States)

    Boldin, Ivan A; Nikolaev, Eugene N

    2009-10-01

    Peak coalescence, i.e. the merging of two close peaks in a Fourier transform ion cyclotron resonance (FTICR) mass spectrum at a high number of ions, plays an important role in various FTICR experiments. In order to describe the coalescence phenomenon we would like to propose a new theory of motion for ion clouds with close mass-to-charge ratios, driven by a uniform magnetic field and Coulomb interactions between the clouds. We describe the motion of the ion clouds in terms of their averaged drift motion in crossed magnetic and electric fields. The ion clouds are considered to be of constant size and their motion is studied in two dimensions. The theory deals with the first-order approximation of the equations of motion in relation to dm/m, where dm is the mass difference and m is the mass of a single ion. The analysis was done for an arbitrary inter-cloud interaction potential, which makes it possible to analyze finite-size ion clouds of any shape. The final analytical expression for the condition of the onset of coalescence is found for the case of uniformly charged spheres. An algorithm for finding this condition for an arbitrary interaction potential is proposed. The critical number of ions for the peak coalescence to take place is shown to depend quadratically on the magnetic field strength and to be proportional to the cyclotron radius and inversely proportional to the ion masses. Copyright (c) 2009 John Wiley & Sons, Ltd.

  13. The Fractional Fourier Transform and Its Application to Energy Localization Problems

    Directory of Open Access Journals (Sweden)

    ter Morsche Hennie G

    2003-01-01

    Full Text Available Applying the fractional Fourier transform (FRFT and the Wigner distribution on a signal in a cascade fashion is equivalent to a rotation of the time and frequency parameters of the Wigner distribution. We presented in ter Morsche and Oonincx, 2002, an integral representation formula that yields affine transformations on the spatial and frequency parameters of the -dimensional Wigner distribution if it is applied on a signal with the Wigner distribution as for the FRFT. In this paper, we show how this representation formula can be used to solve certain energy localization problems in phase space. Examples of such problems are given by means of some classical results. Although the results on localization problems are classical, the application of generalized Fourier transform enlarges the class of problems that can be solved with traditional techniques.

  14. OTDM-WDM Conversion Based on Time-Domain Optical Fourier Transformation with Spectral Compression

    DEFF Research Database (Denmark)

    Mulvad, Hans Christian Hansen; Palushani, Evarist; Galili, Michael

    2011-01-01

    We propose a scheme enabling direct serial-to-parallel conversion of OTDM data tributaries onto a WDM grid, based on optical Fourier transformation with spectral compression. Demonstrations on 320 Gbit/s and 640 Gbit/s OTDM data are shown.......We propose a scheme enabling direct serial-to-parallel conversion of OTDM data tributaries onto a WDM grid, based on optical Fourier transformation with spectral compression. Demonstrations on 320 Gbit/s and 640 Gbit/s OTDM data are shown....

  15. [Research on Application of Fourier Transform Infrared Spectrometry in the Diagnosis of Lymph Node Metastasis in Gastric Cancer].

    Science.gov (United States)

    Bai, Yue-kui; Yu, Li-wei; Zhang, Le; Fu, Jing; Leng, Hui; Yang, Xiao-jun; Ma, Jun-qiang; Li, Xiao-juan; Li, Xiu-juan; Zhu, Qing; Zhang, Yuan-fu; Ling, Xiao-feng; Cao, Wen-lan

    2015-03-01

    To explore the feasibility of quick intraoperative in situ and noninvasive diagnosis of lymph node metastasis in gastric cancer by Fourier transform infrared (FTIR) spectrometry. FTIR spectra of surgically removed fresh lymph nodes were measured by FTIR via probe of attenuated total reflection (ATR). For each spectrum, 13 bands were indentified and assigned between 3 000 and 1 000 cm(-1). Peaks in the spectra were measured and relative intensity ratios were calculated and compared between the spectra of Metastatic lymph nodes (MLN) and Non-metastatic lymph nodes (NMLN). Standard statistic analysis was performed. 720 lymph nodes were measured in 38 gastric cancer patients. Results show that there were significant differences between the FTIR of 540 MLN and 180 NMLN. (1) For the band related to nucleic acid: The ratios of I1240/I1460 (p = 0.015) and I1080/I1460 (p = 0.034) increased in MLN, which shows that the relative quantity of nucleic acid was more in MLN than that in NMLN. (2) For the bands related to protein: The ratios of I1640 /I1460 (p = 0.001) and I146/I1460 (p = 0.027) increased in MLN, which shows that the relative quantity of protein was more in MLN. (3) For the bands related to lipid: The ratio of I2855/I460 and I1740/I1460 decreased in MLN FTIR spectrum, indicating the lower relative quantity of lipid in MLN. (4) For the bands related to carbohydrate: The ratio of I1160/I1460 (p = 0.023) decreased in MLN FTIR spectrum, indicating the lower relative quantity of carbohydrate in MLN. The results demonstrate that the FTIR spectroscopy technique maybe develop into a promising method for in situ and quick intraoperative differential diagnosis of lymph node metastasis in gastric cancer.

  16. Nonlinear Fourier transform for dual-polarization optical communication system

    DEFF Research Database (Denmark)

    Gaiarin, Simone

    communication is considered an emerging paradigm in fiber-optic communications that could potentially overcome these limitations. It relies on a mathematical technique called “inverse scattering transform” or “nonlinear Fourier transform (NFT)” to exploit the “hidden” linearity of the nonlinear Schrödinger...

  17. Pathway confirmation and flux analysis of central metabolic pathways in Desulfovibrio vulgaris Hildenborough using Gas Chromatography-Mass Spectrometry and Fourier Transform-Ion Cyclotron Resonance Mass Spectrometry

    International Nuclear Information System (INIS)

    Tang, Yinjie; Pingitore, Francesco; Mukhopadhyay, Aindrila; Phan, Richard; Hazen, Terry C.; Keasling, Jay D.

    2007-01-01

    Flux distribution in central metabolic pathways of Desulfovibrio vulgaris Hildenborough was examined using 13C tracer experiments. Consistent with the current genome annotation and independent evidence from enzyme activity assays, the isotopomer results from both GC-MS and Fourier Transform-Ion Cyclotron Resonance mass spectrometry (FT-ICR MS) indicate the lack of oxidatively functional TCA cycle and an incomplete pentose phosphate pathway. Results from this study suggest that fluxes through both pathways are limited to biosynthesis. The data also indicate that >80 percent of the lactate was converted to acetate and the reactions involved are the primary route of energy production (NAD(P)H and ATP production). Independent of the TCA cycle, direct cleavage of acetyl-CoA to CO and 5,10-methyl-THF also leads to production of NADH and ATP. Although the genome annotation implicates a ferredoxin-dependent oxoglutarate synthase, isotopic evidence does not support flux through this reaction in either the oxidative or reductive mode; therefore, the TCA cycle is incomplete. FT-ICR MS was used to locate the labeled carbon distribution in aspartate and glutamate and confirmed the presence of an atypical enzyme for citrate formation suggested in previous reports (the citrate synthesized by this enzyme is the isotopic antipode of the citrate synthesized by the (S)-citrate synthase). These findings enable a better understanding of the relation between genome annotation and actual metabolic pathways in D. vulgaris, and also demonstrate FT-ICR MS as a powerful tool for isotopomer analysis, overcoming problems in both GC-MS and NMR spectroscopy

  18. Pulse shaping using the optical Fourier transform technique - for ultra-high-speed signal processing

    DEFF Research Database (Denmark)

    Palushani, Evarist; Oxenløwe, Leif Katsuo; Galili, Michael

    2009-01-01

    This paper reports on the generation of a 1.6 ps FWHM flat-top pulse using the optical Fourier transform technique. The pulse is validated in a 320 Gbit/s demultiplexing experiment.......This paper reports on the generation of a 1.6 ps FWHM flat-top pulse using the optical Fourier transform technique. The pulse is validated in a 320 Gbit/s demultiplexing experiment....

  19. Quaternion Fourier transforms for signal and image processing

    CERN Document Server

    Ell, Todd A; Sangwine, Stephen J

    2014-01-01

    Based on updates to signal and image processing technology made in the last two decades, this text examines the most recent research results pertaining to Quaternion Fourier Transforms. QFT is a central component of processing color images and complex valued signals. The book's attention to mathematical concepts, imaging applications, and Matlab compatibility render it an irreplaceable resource for students, scientists, researchers, and engineers.

  20. Simple surface structure determination from Fourier transforms of angle-resolved photoemission extended fine structure

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Y. [Pennsylvania State Univ., University Park, PA (United States)]|[Lawrence Berkeley Lab., CA (United States); Shirley, D.A. [Pennsylvania State Univ., University Park, PA (United States)

    1995-02-01

    The authors show by Fourier analyses of experimental data, with no further treatment, that the positions of all the strong peaks in Fourier transforms of angle-resolved photoemission extended fine structure (ARPEFS) from adsorbed surfaces can be explicitly predicted from a trial structure with an accuracy of about {+-} 0.3 {angstrom} based on a single-scattering cluster model together with the concept of a strong backscattering cone, and without any additional analysis. This characteristic of ARPEFS Fourier transforms can be developed as a simple method for determining the structures of adsorbed surfaces to an accuracy of about {+-} 0.1 {angstrom}.

  1. Scaled nonuniform Fourier transform for image reconstruction in swept source optical coherence tomography

    Science.gov (United States)

    Mezgebo, Biniyam; Nagib, Karim; Fernando, Namal; Kordi, Behzad; Sherif, Sherif

    2018-02-01

    Swept Source optical coherence tomography (SS-OCT) is an important imaging modality for both medical and industrial diagnostic applications. A cross-sectional SS-OCT image is obtained by applying an inverse discrete Fourier transform (DFT) to axial interferograms measured in the frequency domain (k-space). This inverse DFT is typically implemented as a fast Fourier transform (FFT) that requires the data samples to be equidistant in k-space. As the frequency of light produced by a typical wavelength-swept laser is nonlinear in time, the recorded interferogram samples will not be uniformly spaced in k-space. Many image reconstruction methods have been proposed to overcome this problem. Most such methods rely on oversampling the measured interferogram then use either hardware, e.g., Mach-Zhender interferometer as a frequency clock module, or software, e.g., interpolation in k-space, to obtain equally spaced samples that are suitable for the FFT. To overcome the problem of nonuniform sampling in k-space without any need for interferogram oversampling, an earlier method demonstrated the use of the nonuniform discrete Fourier transform (NDFT) for image reconstruction in SS-OCT. In this paper, we present a more accurate method for SS-OCT image reconstruction from nonuniform samples in k-space using a scaled nonuniform Fourier transform. The result is demonstrated using SS-OCT images of Axolotl salamander eggs.

  2. Dual-polarization nonlinear Fourier transform-based optical communication system

    DEFF Research Database (Denmark)

    Gaiarin, Simone; Perego, A. M.; da Silva, Edson Porto

    2018-01-01

    communication could potentially overcome these limitations. It relies on a mathematical technique called “nonlinear Fourier transform (NFT)” to exploit the “hidden” linearity of the nonlinear Schrödinger equation as the master model for signal propagation in an optical fiber. We present here the theoretical...

  3. Integrated Fourier transform infrared spectroscopy and gas chromatography tandem mass spectrometry for forensic engine lubricating oil and biodiesel analysis

    International Nuclear Information System (INIS)

    Shang, D.

    2009-01-01

    Gas chromatography/mass spectrometry(GC/MS) is commonly used for oil fingerprinting and provides investigators with good forensic data. However, new challenges face oil spill forensic chemistry with the growing use of biodiesel as well as the recycling and reprocessing of used oil, particularly lubricating oils. This paper demonstrated that Fourier transform infrared (FTIR) spectroscopy may be a fast, cost effective and complementary method for forensic analysis of biodiesels (fatty acid methyl esters) and lubricating oils. Attenuated total reflectance (ATR)-FTIR spectroscopy was shown to be an interesting analytic method because of its use in monitoring and quantifying minor chemical compounds in sample matrices and its ability to identify a broad range or organic compounds. Unlike chromatography, FTIR spectroscopy with ATR can provide results without compound separation or lengthy sample preparation steps. This study described the combined use of GC and ATR-FTIR in environmental oil spill identification through the matching of source lube oil samples with artificially weathered samples. Samples recovered from a biodiesel spill incident were also investigated. ATR-FTIR provided detailed spectral information for rapid lube oil differentiation. This study was part of a continuing effort to develop a methodology to deal with chemical spills of unknown origin, which is an important aspect in environmental protection and emergency preparedness. This method was only successfully applied to the short term artificially weathered and fresh lube oil characterization, and to limited cases of biodiesel spills. It was concluded that further validation tests are needed to determine if this method can be applied to real-world weather lube oil samples. 10 refs., 11 figs.

  4. Surface-Induced Dissociation of Protein Complexes in a Hybrid Fourier Transform Ion Cyclotron Resonance Mass Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Jing; Zhou, Mowei; Gilbert, Joshua D.; Wolff, Jeremy J.; Somogyi, Árpád; Pedder, Randall E.; Quintyn, Royston S.; Morrison, Lindsay J.; Easterling, Michael L.; Paša-Tolić, Ljiljana; Wysocki, Vicki H.

    2017-01-03

    Mass spectrometry continues to develop as a valuable tool in the analysis of proteins and protein complexes. In protein complex mass spectrometry studies, surface-induced dissociation (SID) has been successfully applied in quadrupole time-of-flight (Q-TOF) instruments. SID provides structural information on non-covalent protein complexes that is complementary to other techniques. However, the mass resolution of Q-TOF instruments can limit the information that can be obtained for protein complexes by SID. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) provides ultrahigh resolution and ultrahigh mass accuracy measurements. In this study, an SID device was designed and successfully installed in a hybrid FT-ICR instrument in place of the standard gas collision cell. The SID-FT-ICR platform has been tested with several protein complex systems (homooligomers, a heterooligomer, and a protein-ligand complex, ranging from 53 kDa to 85 kDa), and the results are consistent with data previously acquired on Q-TOF platforms, matching predictions from known protein interface information. SID fragments with the same m/z but different charge states are well-resolved based on distinct spacing between adjacent isotope peaks, and the addition of metal cations and ligands can also be isotopically resolved with the ultrahigh mass resolution available in FT-ICR.

  5. Fourier transforms on Cantor sets: A study in non-Diophantine arithmetic and calculus

    International Nuclear Information System (INIS)

    Aerts, Diederik; Czachor, Marek; Kuna, Maciej

    2016-01-01

    Highlights: • Fractal arithmetic allows to define Fourier transforms on Cantor-like sets. • General construction is illustrated on the example of a sawtooth signal. • The formalism is much simpler than the approaches discussed so far in the literature. - Abstract: Fractals equipped with intrinsic arithmetic lead to a natural definition of differentiation, integration, and complex structure. Applying the formalism to the problem of a Fourier transform on fractals we show that the resulting transform has all the required basic properties. As an example we discuss a sawtooth signal on the ternary middle-third Cantor set. The formalism works also for fractals that are not self-similar.

  6. Local structure information by EXAFS analysis using two algorithms for Fourier transform calculation

    International Nuclear Information System (INIS)

    Aldea, N; Pintea, S; Rednic, V; Matei, F; Hu Tiandou; Xie Yaning

    2009-01-01

    The present work is a comparison study between different algorithms of Fourier transform for obtaining very accurate local structure results using Extended X-ray Absorption Fine Structure technique. In this paper we focus on the local structural characteristics of supported nickel catalysts and Fe 3 O 4 core-shell nanocomposites. The radial distribution function could be efficiently calculated by the fast Fourier transform when the coordination shells are well separated while the Filon quadrature gave remarkable results for close-shell coordination.

  7. Fourier transforms in the complex domain

    CERN Document Server

    Wiener, N

    1934-01-01

    With the aid of Fourier-Mellin transforms as a tool in analysis, the authors were able to attack such diverse analytic questions as those of quasi-analytic functions, Mercer's theorem on summability, Milne's integral equation of radiative equilibrium, the theorems of Münz and Szász concerning the closure of sets of powers of an argument, Titchmarsh's theory of entire functions of semi-exponential type with real negative zeros, trigonometric interpolation and developments in polynomials of the form \\sum^N_1A_ne^{i\\lambda_nx}, lacunary series, generalized harmonic analysis in the complex domain,

  8. Eliminating the zero spectrum in Fourier transform profilometry using empirical mode decomposition.

    Science.gov (United States)

    Li, Sikun; Su, Xianyu; Chen, Wenjing; Xiang, Liqun

    2009-05-01

    Empirical mode decomposition is introduced into Fourier transform profilometry to extract the zero spectrum included in the deformed fringe pattern without the need for capturing two fringe patterns with pi phase difference. The fringe pattern is subsequently demodulated using a standard Fourier transform profilometry algorithm. With this method, the deformed fringe pattern is adaptively decomposed into a finite number of intrinsic mode functions that vary from high frequency to low frequency by means of an algorithm referred to as a sifting process. Then the zero spectrum is separated from the high-frequency components effectively. Experiments validate the feasibility of this method.

  9. Closed contour fractal dimension estimation by the Fourier transform

    International Nuclear Information System (INIS)

    Florindo, J.B.; Bruno, O.M.

    2011-01-01

    Highlights: → A novel fractal dimension concept, based on Fourier spectrum, is proposed. → Computationally simple. Computational time smaller than conventional fractal methods. → Results are closer to Hausdorff-Besicovitch than conventional methods. → The method is more accurate and robustness to geometric operations and noise addition. - Abstract: This work proposes a novel technique for the numerical calculus of the fractal dimension of fractal objects which can be represented as a closed contour. The proposed method maps the fractal contour onto a complex signal and calculates its fractal dimension using the Fourier transform. The Fourier power spectrum is obtained and an exponential relation is verified between the power and the frequency. From the parameter (exponent) of the relation, is obtained the fractal dimension. The method is compared to other classical fractal dimension estimation methods in the literature, e.g., Bouligand-Minkowski, box-counting and classical Fourier. The comparison is achieved by the calculus of the fractal dimension of fractal contours whose dimensions are well-known analytically. The results showed the high precision and robustness of the proposed technique.

  10. Principle and analysis of a rotational motion Fourier transform infrared spectrometer

    Science.gov (United States)

    Cai, Qisheng; Min, Huang; Han, Wei; Liu, Yixuan; Qian, Lulu; Lu, Xiangning

    2017-09-01

    Fourier transform infrared spectroscopy is an important technique in studying molecular energy levels, analyzing material compositions, and environmental pollutants detection. A novel rotational motion Fourier transform infrared spectrometer with high stability and ultra-rapid scanning characteristics is proposed in this paper. The basic principle, the optical path difference (OPD) calculations, and some tolerance analysis are elaborated. The OPD of this spectrometer is obtained by the continuously rotational motion of a pair of parallel mirrors instead of the translational motion in traditional Michelson interferometer. Because of the rotational motion, it avoids the tilt problems occurred in the translational motion Michelson interferometer. There is a cosine function relationship between the OPD and the rotating angle of the parallel mirrors. An optical model is setup in non-sequential mode of the ZEMAX software, and the interferogram of a monochromatic light is simulated using ray tracing method. The simulated interferogram is consistent with the theoretically calculated interferogram. As the rotating mirrors are the only moving elements in this spectrometer, the parallelism of the rotating mirrors and the vibration during the scan are analyzed. The vibration of the parallel mirrors is the main error during the rotation. This high stability and ultra-rapid scanning Fourier transform infrared spectrometer is a suitable candidate for airborne and space-borne remote sensing spectrometer.

  11. Determining Energies and Cross Sections of Individual Ions Using Higher-Order Harmonics in Fourier Transform Charge Detection Mass Spectrometry (FT-CDMS).

    Science.gov (United States)

    Harper, Conner C; Elliott, Andrew G; Lin, Haw-Wei; Williams, Evan R

    2018-06-02

    A general method for in situ measurements of the energy of individual ions trapped and weighed using charge detection mass spectrometry (CDMS) is described. Highly charged (> 300 e), individual polyethylene glycol (PEG) ions are trapped and oscillate within an electrostatic trap, producing a time domain signal. A segmented Fourier transform (FT) of this signal yields the temporal evolution of the fundamental and harmonic frequencies of ion motion throughout the 500-ms trap time. The ratio of the fundamental frequency and second harmonic (HAR) depends on the ion energy, which is an essential parameter for measuring ion mass in CDMS. This relationship is calibrated using simulated ion signals, and the calibration is compared to the HAR values measured for PEG ion signals where the ion energy was also determined using an independent method that requires that the ions be highly charged (> 300 e). The mean error of 0.6% between the two measurements indicates that the HAR method is an accurate means of ion energy determination that does not depend on ion size or charge. The HAR is determined dynamically over the entire trapping period, making it possible to observe the change in ion energy that takes place as solvent evaporates from the ion and collisions with background gas occur. This method makes it possible to measure mass changes, either from solvent evaporation or from molecular fragmentation (MS n ), as well as the cross sections of ions measured using CDMS. Graphical Abstract.

  12. Time dependent and asymptotic neutron number probability distribution calculation using discrete Fourier transform

    International Nuclear Information System (INIS)

    Humbert, Ph.

    2005-01-01

    In this paper we consider the probability distribution of neutrons in a multiplying assembly. The problem is studied using a space independent one group neutron point reactor model without delayed neutrons. We recall the generating function methodology and analytical results obtained by G.I. Bell when the c 2 approximation is used and we present numerical solutions in the general case, without this approximation. The neutron source induced distribution is calculated using the single initial neutron distribution which satisfies a master (Kolmogorov backward) equation. This equation is solved using the generating function method. The generating function satisfies a differential equation and the probability distribution is derived by inversion of the generating function. Numerical results are obtained using the same methodology where the generating function is the Fourier transform of the probability distribution. Discrete Fourier transforms are used to calculate the discrete time dependent distributions and continuous Fourier transforms are used to calculate the asymptotic continuous probability distributions. Numerical applications are presented to illustrate the method. (author)

  13. High-resolution magnetic-domain imaging by Fourier transform holography at 21 nm wavelength

    International Nuclear Information System (INIS)

    Schaffert, Stefan; Pfau, Bastian; Günther, Christian M; Schneider, Michael; Korff Schmising, Clemens von; Eisebitt, Stefan; Geilhufe, Jan

    2013-01-01

    Exploiting x-ray magnetic circular dichroism at the L-edges of 3d transition metals, Fourier transform holography has become a standard technique to investigate magnetic samples with sub-100 nm spatial resolution. Here, magnetic imaging in the 21 nm wavelength regime using M-edge circular dichroism is demonstrated. Ultrafast pulses in this wavelength regime are increasingly available from both laser- and accelerator-driven soft x-ray sources. We explain the adaptations concerning sample preparation and data evaluation compared to conventional holography in the 1 nm wavelength range. We find the correction of the Fourier transform hologram to in-plane Fourier components to be critical for high-quality reconstruction and demonstrate 70 nm spatial resolution in magnetization imaging with this approach. (paper)

  14. Structure in the 3D Galaxy Distribution. III. Fourier Transforming the Universe: Phase and Power Spectra

    Energy Technology Data Exchange (ETDEWEB)

    Scargle, Jeffrey D.; Way, M. J.; Gazis, P. R., E-mail: Jeffrey.D.Scargle@nasa.gov, E-mail: Michael.J.Way@nasa.gov, E-mail: PGazis@sbcglobal.net [NASA Ames Research Center, Astrobiology and Space Science Division, Moffett Field, CA 94035 (United States)

    2017-04-10

    We demonstrate the effectiveness of a relatively straightforward analysis of the complex 3D Fourier transform of galaxy coordinates derived from redshift surveys. Numerical demonstrations of this approach are carried out on a volume-limited sample of the Sloan Digital Sky Survey redshift survey. The direct unbinned transform yields a complex 3D data cube quite similar to that from the Fast Fourier Transform of finely binned galaxy positions. In both cases, deconvolution of the sampling window function yields estimates of the true transform. Simple power spectrum estimates from these transforms are roughly consistent with those using more elaborate methods. The complex Fourier transform characterizes spatial distributional properties beyond the power spectrum in a manner different from (and we argue is more easily interpreted than) the conventional multipoint hierarchy. We identify some threads of modern large-scale inference methodology that will presumably yield detections in new wider and deeper surveys.

  15. Structure in the 3D Galaxy Distribution. III. Fourier Transforming the Universe: Phase and Power Spectra

    International Nuclear Information System (INIS)

    Scargle, Jeffrey D.; Way, M. J.; Gazis, P. R.

    2017-01-01

    We demonstrate the effectiveness of a relatively straightforward analysis of the complex 3D Fourier transform of galaxy coordinates derived from redshift surveys. Numerical demonstrations of this approach are carried out on a volume-limited sample of the Sloan Digital Sky Survey redshift survey. The direct unbinned transform yields a complex 3D data cube quite similar to that from the Fast Fourier Transform of finely binned galaxy positions. In both cases, deconvolution of the sampling window function yields estimates of the true transform. Simple power spectrum estimates from these transforms are roughly consistent with those using more elaborate methods. The complex Fourier transform characterizes spatial distributional properties beyond the power spectrum in a manner different from (and we argue is more easily interpreted than) the conventional multipoint hierarchy. We identify some threads of modern large-scale inference methodology that will presumably yield detections in new wider and deeper surveys.

  16. Discrete quantum Fourier transform in coupled semiconductor double quantum dot molecules

    International Nuclear Information System (INIS)

    Dong Ping; Yang Ming; Cao Zhuoliang

    2008-01-01

    In this Letter, we present a physical scheme for implementing the discrete quantum Fourier transform in a coupled semiconductor double quantum dot system. The main controlled-R gate operation can be decomposed into many simple and feasible unitary transformations. The current scheme would be a useful step towards the realization of complex quantum algorithms in the quantum dot system

  17. All-optical signal processing of OTDM and OFDM signals based on time-domain Optical Fourier Transformation

    DEFF Research Database (Denmark)

    Clausen, Anders; Guan, Pengyu; Mulvad, Hans Christian Hansen

    2014-01-01

    All-optical time-domain Optical Fourier Transformation utilised for signal processing of ultra-high-speed OTDM signals and OFDM signals will be presented.......All-optical time-domain Optical Fourier Transformation utilised for signal processing of ultra-high-speed OTDM signals and OFDM signals will be presented....

  18. Analysis of gamma-ray spectra by using fast Fourier transform

    International Nuclear Information System (INIS)

    Tominaga, Shoji; Nagata, Shojiro; Nayatani, Yoshinobu; Ueda, Isamu; Sasaki, Satoshi.

    1977-01-01

    In order to simplify the mass data processing in a response matrix method for γ-ray spectral analysis, a method using a Fast Fourier Transform devised. The validity of the method was confirmed by a computer simulation for spectra of a NaI detector. The method uses the fact that spectral data can be represented by Fourier series with reduced number of terms. The estimation of intensities of γ-ray components is performed by a matrix operation using the compressed data of an observation spectrum and standard spectra in Fourier coefficients. The identification of γ-ray energies is also easy. Several features in the method and a general problem to be solved in a response matrix method are described. (auth.)

  19. Use of fast Fourier transform in gamma-ray spectral analysis

    International Nuclear Information System (INIS)

    Tominaga, Shoji; Nayatani, Yoshinobu; Nagata, Shojiro; Sasaki, Takashi; Ueda, Isamu.

    1978-01-01

    In order to simplify the mass data processing in a response matrix method for γ-ray spectral analysis, a method using a Fast Fourier Transform has been devised. The validity of the method has been confirmed by computer simulation for spectra of a NaI detector. First, it is shown that spectral data can be represented by Fourier series with a reduced number of terms. Then the estimation of intensities of γ-ray components is performed by a matrix operation using the compressed data of an observation spectrum and standard spectra in Fourier coefficients. The identification of γ-ray energies is also easy. Several features of the method and a general problem to be solved in relation to a response matrix method are described. (author)

  20. Potentialities of the atmospheric CO2 remote sensing thanks to static Fourier transform spectrometry

    International Nuclear Information System (INIS)

    Lacan, A.

    2009-04-01

    A global measurement of atmospheric CO 2 concentration is required to improve the prediction of the range of global warming. A satellite mission could provide such a measurement. CNES developed a new generation instrument dedicated to atmospheric sounding. It is a static Fourier transform spectrometer whose mass and size are smaller than those of classical spectrometers. The application of the concept for CO 2 sounding is studied thanks to an on ground experimental bread board representative of a satellite borne spectrometer. The CO 2 concentration is deduced from atmospheric spectra at 1.6 μm thanks to differential spectroscopy technique. The instrumental concept is presented. Then the conception of the spectrometer and the working procedure are described. A study of information content is done. Retrieval simulations show that an error of ±0.6 ppm can be expected, lower than the ±1 ppm goal. Finally the results of a measurement campaign are given. The retrieval precision is compatible with the objectives. Yet the instrument is also sensitive to disruptive parameters. For example deformations of the instrument could engender significant measurement errors. Instrument improvements are proposed to increase the retrieval precision. (author)

  1. A transformada de Fourier em basic The Fourier transform (FFT in basic

    Directory of Open Access Journals (Sweden)

    Mauricio Gomes Constantino

    2000-06-01

    Full Text Available In this paper we describe three computer programs in Basic language about the Fourier transform (FFT which are available in the Internet site http://artemis.ffclrp.usp.br/SoftwareE.htm (in English or http://artemis.ffclrp.usp.br/softwareP.htm (in Portuguese since October 1998. Those are addresses to the Web Page of our Laboratory of Organic Synthesis. The programs can be downloaded and used by anyone who is interested on the subject. The texts, menus and captions in the programs are written in English.

  2. Symmetrized neutron transport equation and the fast Fourier transform method

    International Nuclear Information System (INIS)

    Sinh, N.Q.; Kisynski, J.; Mika, J.

    1978-01-01

    The differential equation obtained from the neutron transport equation by the application of the source iteration method in two-dimensional rectangular geometry is transformed into a symmetrized form with respect to one of the angular variables. The discretization of the symmetrized equation leads to finite difference equations based on the five-point scheme and solved by use of the fast Fourier transform method. Possible advantages of the approach are shown on test calculations

  3. Analytical mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    1990-01-01

    This 43rd Annual Summer Symposium on Analytical Chemistry was held July 24--27, 1990 at Oak Ridge, TN and contained sessions on the following topics: Fundamentals of Analytical Mass Spectrometry (MS), MS in the National Laboratories, Lasers and Fourier Transform Methods, Future of MS, New Ionization and LC/MS Methods, and an extra session. (WET)

  4. On Analog of Fourier Transform in Interior of the Light Cone

    Directory of Open Access Journals (Sweden)

    Tatyana Shtepina

    2014-01-01

    Full Text Available We introduce an analog of Fourier transform Fhρ in interior of light cone that commutes with the action of the Lorentz group. We describe some properties of Fhρ, namely, its action on pseudoradial functions and functions being products of pseudoradial function and space hyperbolic harmonics. We prove that Fhρ-transform gives a one-to-one correspondence on each of the irreducible components of quasiregular representation. We calculate the inverse transform too.

  5. Physiological response of Arundo donax to cadmium stress by Fourier transform infrared spectroscopy.

    Science.gov (United States)

    Yu, Shunhui; Sheng, Li; Zhang, Chunyan; Deng, Hongping

    2018-06-05

    The present paper deals with the physiological response of the changes in chemical contents of the root, stem and leaf of Arundo donax seedlings stressed by excess cadmium using Fourier transform infrared spectroscopy technique, cadmium accumulation in plant by atomic absorption spectroscopy were tested after different concentrations cadmium stress. The results showed that low cadmium concentrations (Fourier transform infrared spectroscopy technique for the non-invasive and rapid monitoring of the plants stressed with heavy metals, Arundo donax is suitable for phytoremediation of cadmium -contaminated wetland. Copyright © 2018 Elsevier B.V. All rights reserved.

  6. The Fourier transform as a signature for chaos in nuclear energy levels

    International Nuclear Information System (INIS)

    Bybee, C.R.; Mitchell, G.E.; Shriner, J.F. Jr.

    1996-01-01

    The Fourier transform of the autocorrelation function is an alternative test to characterize level statistics. For GOE statistics there is a suppression of the Fourier transform near the origin; this correlation hole is absent for Poisson statistics. Numerical modeling has been used to quantify the method and determine the dependence of the correlation-hole area on number, density, sampling interval, and fraction of missing or spurious levels. For large N the normalized correlation-hole area is a nearly universal constant and insensitive to missing and spurious levels. However, for the smaller sample sizes typical of nuclear data, application of the FT method yields ambiguous results. (orig.)

  7. The Fourier transform as a signature for chaos in nuclear energy levels

    Energy Technology Data Exchange (ETDEWEB)

    Bybee, C.R. [North Carolina State Univ., Raleigh, NC (United States)]|[Triangle Universities Nuclear Lab., Durham, NC (United States); Mitchell, G.E. [North Carolina State Univ., Raleigh, NC (United States)]|[Triangle Universities Nuclear Lab., Durham, NC (United States); Shriner, J.F. Jr. [Tennessee Technological Univ., Cookeville (United States)

    1996-08-01

    The Fourier transform of the autocorrelation function is an alternative test to characterize level statistics. For GOE statistics there is a suppression of the Fourier transform near the origin; this correlation hole is absent for Poisson statistics. Numerical modeling has been used to quantify the method and determine the dependence of the correlation-hole area on number, density, sampling interval, and fraction of missing or spurious levels. For large N the normalized correlation-hole area is a nearly universal constant and insensitive to missing and spurious levels. However, for the smaller sample sizes typical of nuclear data, application of the FT method yields ambiguous results. (orig.)

  8. PARTICULATE MATTER MEASUREMENTS USING OPEN-PATH FOURIER TRANSFORM INFRARED SPECTROSCOPY

    Science.gov (United States)

    Open-path Fourier transform infrared (OP-FT1R) spectroscopy is an accepted technology for measuring gaseous air contaminants. OP-FT1R absorbance spectra acquired during changing aerosols conditions reveal related changes in very broad baseline features. Usually, this shearing of ...

  9. Analog fourier transform channelizer and OFDM receiver

    OpenAIRE

    2007-01-01

    An OFDM receiver having an analog multiplier based I-Q channelizing filter, samples and holds consecutive analog I-Q samples of an I-Q baseband, the I-Q basebands having OFDM sub-channels. A lattice of analog I-Q multipliers and analog I-Q summers concurrently receives the held analog I-Q samples, performs analog I-Q multiplications and analog I-Q additions to concurrently generate a plurality of analog I-Q output signals, representing an N-point discrete Fourier transform of the held analog ...

  10. Directional short-time Fourier transform of distributions

    Directory of Open Access Journals (Sweden)

    Katerina Hadzi-Velkova Saneva

    2016-04-01

    Full Text Available Abstract In this paper we consider the directional short-time Fourier transform (DSTFT that was introduced and investigated in (Giv in J. Math. Anal. Appl. 399:100-107, 2013. We analyze the DSTFT and its transpose on test function spaces S ( R n $\\mathcal {S}(\\mathbb {R}^{n}$ and S ( Y 2 n $\\mathcal {S}(\\mathbb {Y}^{2n}$ , respectively, and prove the continuity theorems on these spaces. Then the obtained results are used to extend the DSTFT to spaces of distributions.

  11. Fourier transform inequalities for phylogenetic trees.

    Science.gov (United States)

    Matsen, Frederick A

    2009-01-01

    Phylogenetic invariants are not the only constraints on site-pattern frequency vectors for phylogenetic trees. A mutation matrix, by its definition, is the exponential of a matrix with non-negative off-diagonal entries; this positivity requirement implies non-trivial constraints on the site-pattern frequency vectors. We call these additional constraints "edge-parameter inequalities". In this paper, we first motivate the edge-parameter inequalities by considering a pathological site-pattern frequency vector corresponding to a quartet tree with a negative internal edge. This site-pattern frequency vector nevertheless satisfies all of the constraints described up to now in the literature. We next describe two complete sets of edge-parameter inequalities for the group-based models; these constraints are square-free monomial inequalities in the Fourier transformed coordinates. These inequalities, along with the phylogenetic invariants, form a complete description of the set of site-pattern frequency vectors corresponding to bona fide trees. Said in mathematical language, this paper explicitly presents two finite lists of inequalities in Fourier coordinates of the form "monomial < or = 1", each list characterizing the phylogenetically relevant semialgebraic subsets of the phylogenetic varieties.

  12. Progress report of a static Fourier transform spectrometer breadboard

    Science.gov (United States)

    Rosak, A.; Tintó, F.

    2017-11-01

    MOLI instrument -for MOtionLess Interferometer- takes advantage of the new concept of static Fourier transform spectrometer. It is a high-resolution spectrometer working over a narrow bandwidth, which is adapted to a wide range of atmospheric sounding missions and compatible with micro-satellite platform. The core of this instrument is an echelette cube. Mirrors on the classical design are replaced by stepped mirrors -integrated into that interference cube- thus suppressing any moving part. The steps' directions being set over a perpendicular axis, the overlap of both stepped mirrors creates a cluster of so-called "echelettes", each one corresponding to a different optical path difference (OPD). Hence the Fourier transform of the incoming radiance is directly imaged on a CCD array in a single acquisition. The frequency domain of the measurements is selected by an interferential filter disposed on the incoming optical path. A rotating wheel equipped with several filters allows the successive measurement of spectra around some bands of interest, i.e. O2, CO2 and CO absorption bands.

  13. Fourier transform infrared spectroscopy of peptides.

    Science.gov (United States)

    Bakshi, Kunal; Liyanage, Mangala R; Volkin, David B; Middaugh, C Russell

    2014-01-01

    Fourier transform infrared (FTIR) spectroscopy provides data that are widely used for secondary structure characterization of peptides. A wide array of available sampling methods permits structural analysis of peptides in diverse environments such as aqueous solution (including optically turbid media), powders, detergent micelles, and lipid bilayers. In some cases, side chain vibrations can also be resolved and used for tertiary structure and chemical analysis. Data from several low-resolution spectroscopic techniques, including FTIR, can be combined to generate an empirical phase diagram, an overall picture of peptide structure as a function of environmental conditions that can aid in the global interpretation of large amounts of spectroscopic data.

  14. On a q-extension of Mehta's eigenvectors of the finite Fourier transform for q a root of unity

    OpenAIRE

    Atakishiyeva, Mesuma K.; Atakishiyev, Natig M.; Koornwinder, Tom H.

    2008-01-01

    It is shown that the continuous q-Hermite polynomials for q a root of unity have simple transformation properties with respect to the classical Fourier transform. This result is then used to construct q-extended eigenvectors of the finite Fourier transform in terms of these polynomials.

  15. OTDM-to-WDM Conversion of Complex Modulation Formats by Time-Domain Optical Fourier Transformation

    DEFF Research Database (Denmark)

    Palushani, Evarist; Richter, T.; Ludwig, R.

    2012-01-01

    We demonstrate the utilization of the optical Fourier transform technique for serial-to-parallel conversion of 64×10-GBd OTDM data tributaries with complex modulation formats into 50-GHz DWDM grid without loss of phase and amplitude information.......We demonstrate the utilization of the optical Fourier transform technique for serial-to-parallel conversion of 64×10-GBd OTDM data tributaries with complex modulation formats into 50-GHz DWDM grid without loss of phase and amplitude information....

  16. Products of multiple Fourier series with application to the multiblade transformation

    Science.gov (United States)

    Kunz, D. L.

    1981-01-01

    A relatively simple and systematic method for forming the products of multiple Fourier series using tensor like operations is demonstrated. This symbolic multiplication can be performed for any arbitrary number of series, and the coefficients of a set of linear differential equations with periodic coefficients from a rotating coordinate system to a nonrotating system is also demonstrated. It is shown that using Fourier operations to perform this transformation make it easily understood, simple to apply, and generally applicable.

  17. Discrimination of organic coffee via Fourier transform infrared-photoacoustic spectroscopy.

    Science.gov (United States)

    Gordillo-Delgado, Fernando; Marín, Ernesto; Cortés-Hernández, Diego Mauricio; Mejía-Morales, Claudia; García-Salcedo, Angela Janet

    2012-08-30

    Procedures for the evaluation of the origin and quality of ground and roasted coffee are constantly needed for the associated industry due to complexity of the related market. Conventional Fourier transform infrared (FTIR) spectroscopy can be used for detecting changes in functional groups of compounds, such as coffee. However, dispersion, reflection and non-homogeneity of the sample matrix can cause problems resulting in low spectral quality. On the other hand, sample preparation frequently takes place in a destructive way. To overcome these difficulties, in this work a photoacoustic cell has been adapted as a detector in a FTIR spectrophotometer to perform a study of roasted and ground coffee from three varieties of Coffea arabica grown by organic and conventional methods. Comparison between spectra of coffee recorded by FTIR-photoacoustic spectrometry (PAS) and by FTIR spectrophotometry showed a better resolution of the former method, which, aided by principal components analysis, allowed the identification of some absorption bands that allow the discrimination between organic and conventional coffee. The results obtained provide information about the spectral behavior of coffee powder which can be useful for establishing discrimination criteria. It has been demonstrated that FTIR-PAS can be a useful experimental tool for the characterization of coffee. Copyright © 2012 Society of Chemical Industry.

  18. Spectrogram analysis of selected tremor signals using short-time Fourier transform and continuous wavelet transform

    Energy Technology Data Exchange (ETDEWEB)

    Bartosch, T. [Erlanger-Nuernberg Univ., Erlanger (Germany). Lehrstul fuer Nachrichtentechnik I; Seidl, D. [Seismologisches Zentralobservatorium Graefenberg, Erlanegen (Greece). Bundesanstalt fuer Geiwissenschaften und Rohstoffe

    1999-06-01

    Among a variety of spectrogram methods short-time Fourier transform (STFT) and continuous wavelet transform (CWT) were selected to analyse transients in non-stationary signals. Depending on the properties of the tremor signals from the volcanos Mt. Stromboli, Mt. Semeru and Mt. Pinatubo were analyzed using both methods. The CWT can also be used to extend the definition of coherency into a time-varying coherency spectrogram. An example is given using array data from the volcano Mt. Stromboli (Italy).

  19. Novel molecular-level evidence of iodine binding to natural organic matter from Fourier transform ion cyclotron resonance mass spectrometry

    International Nuclear Information System (INIS)

    Xu, Chen; Chen, Hongmei; Sugiyama, Yuko; Zhang, Saijin; Li, Hsiu-Ping; Ho, Yi-Fang; Chuang, Chia-ying; Schwehr, Kathleen A.; Kaplan, Daniel I.; Yeager, Chris; Roberts, Kimberly A.; Hatcher, Patrick G.; Santschi, Peter H.

    2013-01-01

    Major fractions of radioiodine ( 129 I) are associated with natural organic matter (NOM) in the groundwater and surface soils of the Savannah River Site (SRS). Electrospray ionization coupled to Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR-MS) was applied to elucidate the interactions between inorganic iodine species (iodide and iodate) and a fulvic acid (FA) extracted from a SRS surface soil. Iodate is likely reduced to reactive iodine species by the lignin- and tannin-like compounds or the carboxylic-rich alicyclic molecules (CRAM), during which condensed aromatics and lignin-like compounds were generated. Iodide is catalytically oxidized into reactive iodine species by peroxides, while FA is oxidized by peroxides into more aliphatic and less aromatic compounds. Only 9% of the total identified organo-iodine compounds derived from molecules originally present in the FA, whereas most were iodine binding to newly-produced compounds. The resulting iodinated molecules were distributed in three regions in the van Krevelen diagrams, denoting unsaturated hydrocarbons, lignin and protein. Moreover, characteristics of these organo-iodine compounds, such as their relatively low O/C ratios ( 2 or -HNCOR groups and a ring-activating functionality to favor the electrophilic substitution. The ESI-FTICR-MS technique provides novel evidence to better understand the reactivity and scavenging properties of NOM towards radioiodine and possible influence of NOM on 129 I migration. Highlights: ► IO 3 − reduced by lignin-, tannin-like compounds/carboxylic-rich alicyclic molecules ► Condensed aromatic and lignin-like compounds generated after iodate-iodination ► Aliphatic and less aromatic compounds formed after iodide-iodination ► Organo-iodine identified as unsaturated hydrocarbons, lignin and protein ► Organo-iodine with low O/C ratios imply less environmental mobility

  20. Numerical computation of the discrete Fourier transform and its applications in the statistic processing of experimental data

    International Nuclear Information System (INIS)

    Marinescu, D.C.; Radulescu, T.G.

    1977-06-01

    The Integral Fourier Transform has a large range of applications in such areas as communication theory, circuit theory, physics, etc. In order to perform discrete Fourier Transform the Finite Fourier Transform is defined; it operates upon N samples of a uniformely sampled continuous function. All the properties known in the continuous case can be found in the discrete case also. The first part of the paper presents the relationship between the Finite Fourier Transform and the Integral one. The computing of a Finite Fourier Transform is a problem in itself since in order to transform a set of N data we have to perform N 2 ''operations'' if the transformation relations are used directly. An algorithm known as the Fast Fourier Transform (FFT) reduces this figure from N 2 to a more reasonable Nlog 2 N, when N is a power of two. The original Cooley and Tuckey algorithm for FFT can be further improved when higher basis are used. The price to be paid in this case is the increase in complexity of such algorithms. The recurrence relations and a comparation among such algorithms are presented. The key point in understanding the application of FFT resides in the convolution theorem which states that the convolution (an N 2 type procedure) of the primitive functions is equivalent to the ordinar multiplication of their transforms. Since filtering is actually a convolution process we present several procedures to perform digital filtering by means of FFT. The best is the one using the segmentation of records and the transformation of pairs of records. In the digital processing of signals, besides digital filtering a special attention is paid to the estimation of various statistical characteristics of a signal as: autocorrelation and correlation functions, periodiograms, density power sepctrum, etc. We give several algorithms for the consistent and unbiased estimation of such functions, by means of FFT. (author)

  1. How to use the Fast Fourier Transform in Large Finite Fields

    OpenAIRE

    Petersen, Petur Birgir

    2011-01-01

    The article contents suggestions on how to perform the Fast Fourier Transform over Large Finite Fields. The technique is to use the fact that the multiplicative groups of specific prime fields are surprisingly composite.

  2. Stress wave calculations in composite plates using the fast Fourier transform.

    Science.gov (United States)

    Moon, F. C.

    1973-01-01

    The protection of composite turbine fan blades against impact forces has prompted the study of dynamic stresses in composites due to transient loads. The mathematical model treats the laminated plate as an equivalent anisotropic material. The use of Mindlin's approximate theory of crystal plates results in five two-dimensional stress waves. Three of the waves are flexural and two involve in-plane extensional strains. The initial value problem due to a transient distributed transverse force on the plate is solved using Laplace and Fourier transforms. A fast computer program for inverting the two-dimensional Fourier transform is used. Stress contours for various stresses and times after application of load are obtained for a graphite fiber-epoxy matrix composite plate. Results indicate that the points of maximum stress travel along the fiber directions.

  3. Experimental demonstrations of the properties of Fourier transforms using diffraction phenomena

    International Nuclear Information System (INIS)

    Bazin, M.J.; Lucie, P.H.; Oliveira, S.M.M. de.

    1984-01-01

    The standard mathematical properties of Fourier transforms and the experimental characteristics of diffraction phenomena are systematically brought together. An experimental realization of a particular case of the convolution theorem is displayed in details. (Author) [pt

  4. Direct-on-Filter α-Quartz Estimation in Respirable Coal Mine Dust Using Transmission Fourier Transform Infrared Spectrometry and Partial Least Squares Regression.

    Science.gov (United States)

    Miller, Arthur L; Weakley, Andrew Todd; Griffiths, Peter R; Cauda, Emanuele G; Bayman, Sean

    2017-05-01

    In order to help reduce silicosis in miners, the National Institute for Occupational Health and Safety (NIOSH) is developing field-portable methods for measuring airborne respirable crystalline silica (RCS), specifically the polymorph α-quartz, in mine dusts. In this study we demonstrate the feasibility of end-of-shift measurement of α-quartz using a direct-on-filter (DoF) method to analyze coal mine dust samples deposited onto polyvinyl chloride filters. The DoF method is potentially amenable for on-site analyses, but deviates from the current regulatory determination of RCS for coal mines by eliminating two sample preparation steps: ashing the sampling filter and redepositing the ash prior to quantification by Fourier transform infrared (FT-IR) spectrometry. In this study, the FT-IR spectra of 66 coal dust samples from active mines were used, and the RCS was quantified by using: (1) an ordinary least squares (OLS) calibration approach that utilizes standard silica material as done in the Mine Safety and Health Administration's P7 method; and (2) a partial least squares (PLS) regression approach. Both were capable of accounting for kaolinite, which can confound the IR analysis of silica. The OLS method utilized analytical standards for silica calibration and kaolin correction, resulting in a good linear correlation with P7 results and minimal bias but with the accuracy limited by the presence of kaolinite. The PLS approach also produced predictions well-correlated to the P7 method, as well as better accuracy in RCS prediction, and no bias due to variable kaolinite mass. Besides decreased sensitivity to mineral or substrate confounders, PLS has the advantage that the analyst is not required to correct for the presence of kaolinite or background interferences related to the substrate, making the method potentially viable for automated RCS prediction in the field. This study demonstrated the efficacy of FT-IR transmission spectrometry for silica determination in

  5. Calibration of the Herschel SPIRE Fourier Transform Spectrometer

    OpenAIRE

    Swinyard, Bruce; Polehampton, E. T.; Hopwood, R.; Valtchanov, I.; Lu, N.; Fulton, T.; Benielli, D.; Imhof, P.; Marchili, N.; Baluteau, J.- P.; Bendo, G. J.; Ferlet, M.; Griffin, Matthew Jason; Lim, T. L.; Makiwa, G.

    2014-01-01

    The Herschel Spectral and Photometric REceiver (SPIRE) instrument consists of an imaging photometric camera and an imaging Fourier Transform Spectrometer (FTS), both operating over a frequency range of ∼450–1550 GHz. In this paper, we briefly review the FTS design, operation, and data reduction, and describe in detail the approach taken to relative calibration (removal of instrument signatures) and absolute calibration against standard astronomical sources. The calibration scheme assumes a sp...

  6. On Fourier re-expansions

    OpenAIRE

    Liflyand, E.

    2012-01-01

    We study an extension to Fourier transforms of the old problem on absolute convergence of the re-expansion in the sine (cosine) Fourier series of an absolutely convergent cosine (sine) Fourier series. The results are obtained by revealing certain relations between the Fourier transforms and their Hilbert transforms.

  7. All-optical signal processing of OTDM and OFDM signals based on time-domain optical fourier transformation

    DEFF Research Database (Denmark)

    Galili, Michael; Guan, Pengyu; Lillieholm, Mads

    2017-01-01

    In the talk, we will review recent work on optical signal processing based on time lenses. Various applications of optical Fourier transformation for optical communications will be discussed.......In the talk, we will review recent work on optical signal processing based on time lenses. Various applications of optical Fourier transformation for optical communications will be discussed....

  8. Subwavelength Fourier-transform imaging without a lens or a beamsplitter

    International Nuclear Information System (INIS)

    Liu Rui-Feng; Yuan Xin-Xing; Fang Yi-Zhen; Zhang Pei; Zhou Yu; Gao Hong; Li Fu-Li

    2014-01-01

    The fourier-transform patterns of an object are usually observed in the far-field region or obtained in the near-field region with the help of lenses. Here we propose and experimentally demonstrate a scheme of Fourier-transform patterns in the Fresnel diffraction region with thermal light. In this scheme, neither a lens nor a beamsplitter is used, and only one single charge coupled device (CCD) is employed. It means that dividing one beam out of a light source into signal and reference beams is not as necessary as the one done by the use of a beamsplitter in usual ghost interference experiments. Moreover, the coincidence measurement of two point detectors is not necessary and data recorded on a single CCD are sufficient for reconstructing the ghost diffraction patterns. The feature of the scheme promises a great potential application in the fields of X-ray and neutron diffraction imaging processes. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  9. Description of the electron-hydrogen collision by the Coulomb Fourier transform method

    International Nuclear Information System (INIS)

    Levin, S.B.

    2005-01-01

    A recently developed Coulomb Fourier Transform method is applied to the system containing one heavy ion and two electrons. The transformed Hamiltonian is described with a controlled accuracy in an effective finite basis set as a finite dimensional operator matrix. The kernels of interaction are formulated in terms of the so called Nordsieck integrals

  10. Kinetic study of olive oil degradation monitored by fourier transform infrared spectrometry. Application to oil characterization.

    Science.gov (United States)

    Román Falcó, Iván P; Grané Teruel, Nuria; Prats Moya, Soledad; Martín Carratalá, M Luisa

    2012-11-28

    A new approach for the determination of kinetic parameters of the cis/trans isomerization during the oxidation process of 24 virgin olive oils belonging to 8 different varieties is presented. The accelerated process of degradation at 100 °C was monitored by recording the Fourier transform infrared spectra. The parameters obtained confirm pseudo-first-order kinetics for the degradation of cis and the appearance of trans double bonds. The kinetic approach affords the induction time and the rate coefficient; these parameters are related to the fatty acid profile of the fresh olive oils. The data obtained were used to compare the oil stability of the samples with the help of multivariate statistical techniques. Fatty acid allowed a classification of the samples in five groups, one of them constituted by the cultivars with higher stability. Meanwhile, the kinetic parameters showed greater ability for the characterization of olive oils, allowing the classification in seven groups.

  11. Fourier transform distribution function of relaxation times; application and limitations

    NARCIS (Netherlands)

    Boukamp, Bernard A.

    2015-01-01

    A simple Fourier transform (FT) method is presented for obtaining a Distribution Function of Relaxation Times (DFRT) for electrochemical impedance spectroscopy (EIS) data. By using a special data extension procedure the FT is performed over the range from -∞ ≤ lnω ≤ + ∞. The integration procedure is

  12. Orthonormal mode sets for the two-dimensional fractional Fourier transformation

    NARCIS (Netherlands)

    Alieva, T.; Bastiaans, M.J.

    2007-01-01

    A family of orthonormal mode sets arises when Hermite–Gauss modes propagate through lossless first-order optical systems. It is shown that the modes at the output of the system are eigenfunctions for the symmetric fractional Fourier transformation if and only if the system is described by an

  13. Fatty acidomics: Evaluation of the effects of thermal treatments on commercial mussels through an extended characterization of their free fatty acids by liquid chromatography - Fourier transform mass spectrometry.

    Science.gov (United States)

    Losito, Ilario; Facchini, Laura; Valentini, Alessandra; Cataldi, Tommaso R I; Palmisano, Francesco

    2018-07-30

    An unprecedented characterization of free fatty acids (FFA) in the lipid extracts of fresh or thermally treated mussels of sp. Mytilus galloprovincialis, including up to 128 saturated, mono- or poly-unsaturated and 63 oxidized (i.e., modified by hydroxylic, carbonylic and/or epoxylic groups) compounds, was achieved using reverse phase chromatography coupled to electrospray ionization-Fourier transform single and tandem mass spectrometry (RPC-ESI-FTMS,MS/MS). Subsequent Principal Components Analysis (PCA) evidenced several effects of thermal treatments on the mussel FFA profiles. In particular, death-inducing low temperature treatments (freezing at -16 °C or refrigeration at 4 °C for several days) induced a peculiar increase in the incidence of FFA, whereas the effect was absent in mussels undergoing death upon prolonged storage at room temperature (25 °C, 6 h) or fast cooking (100 °C, 5 min). Alive mussels, either fresh or resulting from short term (up to 48 h) refrigeration were actually indistinguishable by PCA, although subtle seasonal effects were observed. Copyright © 2018. Published by Elsevier Ltd.

  14. The Use of Continuous Wavelet Transform Based on the Fast Fourier Transform in the Analysis of Multi-channel Electrogastrography Recordings.

    Science.gov (United States)

    Komorowski, Dariusz; Pietraszek, Stanislaw

    2016-01-01

    This paper presents the analysis of multi-channel electrogastrographic (EGG) signals using the continuous wavelet transform based on the fast Fourier transform (CWTFT). The EGG analysis was based on the determination of the several signal parameters such as dominant frequency (DF), dominant power (DP) and index of normogastria (NI). The use of continuous wavelet transform (CWT) allows for better visible localization of the frequency components in the analyzed signals, than commonly used short-time Fourier transform (STFT). Such an analysis is possible by means of a variable width window, which corresponds to the scale time of observation (analysis). Wavelet analysis allows using long time windows when we need more precise low-frequency information, and shorter when we need high frequency information. Since the classic CWT transform requires considerable computing power and time, especially while applying it to the analysis of long signals, the authors used the CWT analysis based on the fast Fourier transform (FFT). The CWT was obtained using properties of the circular convolution to improve the speed of calculation. This method allows to obtain results for relatively long records of EGG in a fairly short time, much faster than using the classical methods based on running spectrum analysis (RSA). In this study authors indicate the possibility of a parametric analysis of EGG signals using continuous wavelet transform which is the completely new solution. The results obtained with the described method are shown in the example of an analysis of four-channel EGG recordings, performed for a non-caloric meal.

  15. Utilização de filtro de transformada de fourier para a minimização de ruídos em sinais analíticos Utilization of fourier transform filter for noise minimization in analytical signals

    Directory of Open Access Journals (Sweden)

    Eduardo O. Cerqueira

    2000-10-01

    Full Text Available Instrumental data always present some noise. The analytical data information and instrumental noise generally has different frequencies. Thus is possible to remove the noise using a digital filter based on Fourier transform and inverse Fourier transform. This procedure enhance the signal/noise ratio and consecutively increase the detection limits on instrumental analysis. The basic principle of Fourier transform filter with modifications implemented to improve its performance is presented. A numerical example, as well as a real voltammetric example are showed to demonstrate the Fourier transform filter implementation. The programs to perform the Fourier transform filter, in Matlab and Visual Basic languages, are included as appendices

  16. Assisted inhibition effect of acetylcholinesterase with n-octylphosphonic acid and application in high sensitive detection of organophosphorous pesticides by matrix-assisted laser desorption/ionization Fourier transform mass spectrometry.

    Science.gov (United States)

    Cai, Tingting; Zhang, Li; Wang, Haoyang; Zhang, Jing; Guo, Yinlong

    2011-11-14

    A simple and practical approach to improve the sensitivity of acetylcholinesterase (AChE)-inhibited method has been developed for monitoring organophosphorous (OP) pesticide residues. In this work, matrix-assisted laser desorption/ionization Fourier transform mass spectrometry (MALDI-FTMS) was used to detect AChE activity. Due to its good salt-tolerance and low sample consumption, MALDI-FTMS facilitates rapid and high-throughput screening of OP pesticides. Here we describe a new method to obtain low detection limits via employing external reagents. Among candidate compounds, n-octylphosphonic acid (n-Octyl-PA) displays assistant effect to enhance AChE inhibition by OP pesticides. In presence of n-Octyl-PA, the percentages of AChE inhibition still kept correlation with OP pesticide concentrations. The detection limits were improved significantly even by 10(2)-10(3) folds in comparison with conventional enzyme-inhibited methods. Different detection limits of OP pesticides with different toxicities were as low as 0.005 μg L(-1) for high toxic pesticides and 0.05 μg L(-1) for low toxic pesticides. Besides, the reliability of results from this method to analyze cowpea samples had been demonstrated by liquid-chromatography tandem mass spectrometry (LC-MS/MS). The application of this commercial available assistant agent shows great promise to detect OP compounds in complicated biological matrix and broadens the mind for high sensitivity detection of OP pesticide residues in agricultural products. Copyright © 2011 Elsevier B.V. All rights reserved.

  17. Analytical mass spectrometry. Abstracts

    Energy Technology Data Exchange (ETDEWEB)

    1990-12-31

    This 43rd Annual Summer Symposium on Analytical Chemistry was held July 24--27, 1990 at Oak Ridge, TN and contained sessions on the following topics: Fundamentals of Analytical Mass Spectrometry (MS), MS in the National Laboratories, Lasers and Fourier Transform Methods, Future of MS, New Ionization and LC/MS Methods, and an extra session. (WET)

  18. Morphological and chemical changes in dentin after using endodontic agents: Fourier transform Raman spectroscopy, energy-dispersive x-ray fluorescence spectrometry, and scanning electron microscopy study

    Science.gov (United States)

    Pascon, Fernanda Miori; Kantovitz, Kamila Rosamilia; Soares, Luís Eduardo Silva; Santo, Ana Maria do Espírito; Martin, Airton Abraha~o.; Puppin-Rontani, Regina Maria

    2012-07-01

    We examine the morphological and chemical changes in the pulp chamber dentin after using endodontic agents by scanning electron microscopy (SEM), Fourier transform Raman spectroscopy (FT-Raman), and micro energy-dispersive x-ray fluorescence spectrometry (μEDXRF). Thirty teeth were sectioned exposing the pulp chamber and divided by six groups (n=5): NT-no treatment; CHX-2% chlorhexidine; CHXE-2% chlorhexidine+17% EDTA E-17% EDTA; SH5-5.25% NaOCl; SH5E-5.25% NaOCl+17% EDTA. The inorganic and organic content was analyzed by FT-Raman. μEDXRF examined calcium (Ca) and phosphorus (P) content as well as Ca/P ratio. Impressions of specimens were evaluated by SEM. Data were submitted to Kruskal-Wallis and Dunn tests (pNT=SH5E>CHX>E>CHXE). CHXE and E presented the highest Ca/P ratio values compared to the other groups (p<0.05). The SEM images in the EDTA-treated groups had the highest number of open tubules. Erosion in the tubules was observed in CHX and SH5E groups. Endodontic agents change the inorganic and organic content of pulp chamber dentin. NaOCl used alone, or in association with EDTA, was the most effective agent considering chemical and morphological approaches.

  19. Tabletop single-shot extreme ultraviolet Fourier transform holography of an extended object.

    Science.gov (United States)

    Malm, Erik B; Monserud, Nils C; Brown, Christopher G; Wachulak, Przemyslaw W; Xu, Huiwen; Balakrishnan, Ganesh; Chao, Weilun; Anderson, Erik; Marconi, Mario C

    2013-04-22

    We demonstrate single and multi-shot Fourier transform holography with the use of a tabletop extreme ultraviolet laser. The reference wave was produced by a Fresnel zone plate with a central opening that allowed the incident beam to illuminate the sample directly. The high reference wave intensity allows for larger objects to be imaged compared to mask-based lensless Fourier transform holography techniques. We obtain a spatial resolution of 169 nm from a single laser pulse and a resolution of 128 nm from an accumulation of 20 laser pulses for an object ~11x11μm(2) in size. This experiment utilized a tabletop extreme ultraviolet laser that produces a highly coherent ~1.2 ns laser pulse at 46.9 nm wavelength.

  20. Comprehensive characterization of natural organic matter by MALDI- and ESI-Fourier transform ion cyclotron resonance mass spectrometry

    International Nuclear Information System (INIS)

    Cao, Dong; Huang, Huogao; Hu, Ming; Cui, Lin; Geng, Fanglan; Rao, Ziyu; Niu, Hongyun; Cai, Yaqi; Kang, Yuehui

    2015-01-01

    Highlights: • MALDI-FT-ICR-MS was firstly employed for molecular characterization of NOM. • 1,8-Bis(dimethyl-amino)-naphthalene (DMAN) was used as matrix. • Mass spectra of NOM generated by MALDI and ESI methods were compared. • Complementary molecular information of NOM was provided by MALDI. - Abstract: Natural organic matter (NOM) is a complex and non-uniform mixture of organic compounds which plays an important role in environmental processes. Due to the complexity, it is challenging to obtain fully detailed structural information about NOM. Although Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) has been demonstrated to be a powerful tool for providing molecular information about NOM, multiple ionization methods are needed for comprehensive characterization of NOM at the molecular level considering the ionizing selectivity of different ionization methods. This paper reports the first use of matrix assisted laser desorption/ionization (MALDI) method coupled with FT-ICR-MS for molecular characterization of NOM within a mass range of 200–800 Da. The mass spectral data obtained by MALDI were systematically compared with data generated by electrospray ionization (ESI). It showed that complementary molecular information about NOM which could not be detected by ESI, were provided by MALDI. More unsaturated and aromatic constituents of NOM with lower O/C ratio (O/C ratio < 0.5) were preferentially ionized in MALDI negative mode, whereas more polar constituents of NOM with higher O/C ratio were preferentially ionized in ESI negative mode. Molecular anions of NOM appearing at even m/z in MALDI negative ion mode were detected. The results show that NOM molecules with aromatic structures, moderate O/C ratio (0.7 > O/C ratio > 0.25) and lower H/C ratio were liable to form molecular anions at even m/z, whereas those with higher H/C ratio are more likely to form deprotonated ions at odd m/z. It is speculated that almost half of the NOM

  1. Discrete Fourier and wavelet transforms an introduction through linear algebra with applications to signal processing

    CERN Document Server

    Goodman, Roe W

    2016-01-01

    This textbook for undergraduate mathematics, science, and engineering students introduces the theory and applications of discrete Fourier and wavelet transforms using elementary linear algebra, without assuming prior knowledge of signal processing or advanced analysis.It explains how to use the Fourier matrix to extract frequency information from a digital signal and how to use circulant matrices to emphasize selected frequency ranges. It introduces discrete wavelet transforms for digital signals through the lifting method and illustrates through examples and computer explorations how these transforms are used in signal and image processing. Then the general theory of discrete wavelet transforms is developed via the matrix algebra of two-channel filter banks. Finally, wavelet transforms for analog signals are constructed based on filter bank results already presented, and the mathematical framework of multiresolution analysis is examined.

  2. Application of fast Fourier transform cross-correlation and mass spectrometry data for accurate alignment of chromatograms.

    Science.gov (United States)

    Zheng, Yi-Bao; Zhang, Zhi-Min; Liang, Yi-Zeng; Zhan, De-Jian; Huang, Jian-Hua; Yun, Yong-Huan; Xie, Hua-Lin

    2013-04-19

    Chromatography has been established as one of the most important analytical methods in the modern analytical laboratory. However, preprocessing of the chromatograms, especially peak alignment, is usually a time-consuming task prior to extracting useful information from the datasets because of the small unavoidable differences in the experimental conditions caused by minor changes and drift. Most of the alignment algorithms are performed on reduced datasets using only the detected peaks in the chromatograms, which means a loss of data and introduces the problem of extraction of peak data from the chromatographic profiles. These disadvantages can be overcome by using the full chromatographic information that is generated from hyphenated chromatographic instruments. A new alignment algorithm called CAMS (Chromatogram Alignment via Mass Spectra) is present here to correct the retention time shifts among chromatograms accurately and rapidly. In this report, peaks of each chromatogram were detected based on Continuous Wavelet Transform (CWT) with Haar wavelet and were aligned against the reference chromatogram via the correlation of mass spectra. The aligning procedure was accelerated by Fast Fourier Transform cross correlation (FFT cross correlation). This approach has been compared with several well-known alignment methods on real chromatographic datasets, which demonstrates that CAMS can preserve the shape of peaks and achieve a high quality alignment result. Furthermore, the CAMS method was implemented in the Matlab language and available as an open source package at http://www.github.com/matchcoder/CAMS. Copyright © 2013. Published by Elsevier B.V.

  3. Coulomb Fourier transformation: A novel approach to three-body scattering with charged particles

    International Nuclear Information System (INIS)

    Alt, E.O.; Levin, S.B.; Yakovlev, S.L.

    2004-01-01

    A unitary transformation of the three-body Hamiltonian which describes a system of two charged and one neutral particles is constructed such that the Coulomb potential which acts between the charged particles is explicitly eliminated. The transformed Hamiltonian and, in particular, the transformed short-range pair interactions are worked out in detail. Thereby it is found that, after transformation, the short-range potentials acting between the neutral and either one of the charged particles become simply Fourier transformed but, in addition, multiplied by a function that represents the Coulombic three-body correlations originating from the action of the other charged particle on the considered pair. This function which is universal as it does not depend on any property of the short-range interaction is evaluated explicitly and its singularity structure is described in detail. In contrast, the short-range potential between the charged particles remains of two-body type but occurs now in the 'Coulomb representation'. Specific applications to Yukawa and Gaussian potentials are given. Since the Coulomb-Fourier-transformed Hamiltonian does no longer contain the Coulomb potential or any other effective interaction of long range, standard methods of short-range few-body scattering theory are applicable

  4. A gain and bandwidth enhanced transimpedance preamplifier for Fourier-transform ion cyclotron resonance mass spectrometry

    International Nuclear Information System (INIS)

    Lin, Tzu-Yung; Green, Roger J.; O'Connor, Peter B.

    2011-01-01

    The nature of the ion signal from a 12-T Fourier-transform ion cyclotron resonance mass spectrometer and the electronic noise were studied to further understand the electronic detection limit. At minimal cost, a new transimpedance preamplifier was designed, computer simulated, built, and tested. The preamplifier design pushes the electronic signal-to-noise performance at room temperature to the limit, because of its enhanced tolerance of the capacitance of the detection device, lower intrinsic noise, and larger flat mid-band gain (input current noise spectral density of around 1 pA/√(Hz) when the transimpedance is about 85 dBΩ). The designed preamplifier has a bandwidth of ∼3 kHz to 10 MHz, which corresponds to the mass-to-charge ratio, m/z, of approximately 18 to 61 k at 12 T. The transimpedance and the bandwidth can be easily adjusted by changing the value of passive components. The feedback limitation of the circuit is discussed. With the maximum possible transimpedance of 5.3 MΩ when using an 0402 surface mount resistor, the preamplifier was estimated to be able to detect ∼110 charges in a single scan.

  5. Comparative study of wine tannin classification using Fourier transform mid-infrared spectrometry and sensory analysis.

    Science.gov (United States)

    Fernández, Katherina; Labarca, Ximena; Bordeu, Edmundo; Guesalaga, Andrés; Agosin, Eduardo

    2007-11-01

    Wine tannins are fundamental to the determination of wine quality. However, the chemical and sensorial analysis of these compounds is not straightforward and a simple and rapid technique is necessary. We analyzed the mid-infrared spectra of white, red, and model wines spiked with known amounts of skin or seed tannins, collected using Fourier transform mid-infrared (FT-MIR) transmission spectroscopy (400-4000 cm(-1)). The spectral data were classified according to their tannin source, skin or seed, and tannin concentration by means of discriminant analysis (DA) and soft independent modeling of class analogy (SIMCA) to obtain a probabilistic classification. Wines were also classified sensorially by a trained panel and compared with FT-MIR. SIMCA models gave the most accurate classification (over 97%) and prediction (over 60%) among the wine samples. The prediction was increased (over 73%) using the leave-one-out cross-validation technique. Sensory classification of the wines was less accurate than that obtained with FT-MIR and SIMCA. Overall, these results show the potential of FT-MIR spectroscopy, in combination with adequate statistical tools, to discriminate wines with different tannin levels.

  6. Novel Polynomial Basis with Fast Fourier Transform and Its Application to Reed-Solomon Erasure Codes

    KAUST Repository

    Lin, Sian-Jheng

    2016-09-13

    In this paper, we present a fast Fourier transform (FFT) algorithm over extension binary fields, where the polynomial is represented in a non-standard basis. The proposed Fourier-like transform requires O(h lg(h)) field operations, where h is the number of evaluation points. Based on the proposed Fourier-like algorithm, we then develop the encoding/ decoding algorithms for (n = 2m; k) Reed-Solomon erasure codes. The proposed encoding/erasure decoding algorithm requires O(n lg(n)), in both additive and multiplicative complexities. As the complexity leading factor is small, the proposed algorithms are advantageous in practical applications. Finally, the approaches to convert the basis between the monomial basis and the new basis are proposed.

  7. The smoothing and fast Fourier transformation of experimental X-ray and neutron data from amorphous materials

    International Nuclear Information System (INIS)

    Dixon, M.; Wright, A.C.; Hutchinson, P.

    1977-01-01

    The application of fast Fourier transformation techniques to the analysis of experimental X-ray and neutron diffraction patterns from amorphous materials is discussed and compared with conventional techniques using Filon's quadrature. The fast Fourier transform package described also includes cubic spline smoothing and has been extensively tested, using model data to which statistical errors have been added by means of a pseudo-random number generator with Gaussian shaper. Neither cubic spline nor hand smoothing has much effect on the resulting transform since the noise removed is of too high a frequency. (Auth.)

  8. Bi-centenary of successes of Fourier theorem: its power and limitations in optical system designs

    Science.gov (United States)

    Roychoudhuri, Chandrasekhar

    2007-09-01

    We celebrate the two hundred years of successful use of the Fourier theorem in optics. However, there is a great enigma associated with the Fourier transform integral. It is one of the most pervasively productive and useful tool of physics and optics because its foundation is based on the superposition of harmonic functions and yet we have never declared it as a principle of physics for valid reasons. And, yet there are a good number of situations where we pretend it to be equivalent to the superposition principle of physics, creating epistemological problems of enormous magnitude. The purpose of the paper is to elucidate the problems while underscoring the successes and the elegance of the Fourier theorem, which are not explicitly discussed in the literature. We will make our point by taking six major engineering fields of optics and show in each case why it works and under what restricted conditions by bringing in the relevant physics principles. The fields are (i) optical signal processing, (ii) Fourier transform spectrometry, (iii) classical spectrometry of pulsed light, (iv) coherence theory, (v) laser mode locking and (vi) pulse broadening. We underscore that mathematical Fourier frequencies, not being physical frequencies, cannot generate real physical effects on our detectors. Appreciation of this fundamental issue will open up ways to be innovative in many new optical instrument designs. We underscore the importance of always validating our design platforms based on valid physics principles (actual processes undergoing in nature) captured by an appropriate hypothesis based on diverse observations. This paper is a comprehensive view of the power and limitations of Fourier Transform by summarizing a series of SPIE conference papers presented during 2003-2007.

  9. Qualitative metabolome analysis of human cerebrospinal fluid by 13C-/12C-isotope dansylation labeling combined with liquid chromatography Fourier transform ion cyclotron resonance mass spectrometry.

    Science.gov (United States)

    Guo, Kevin; Bamforth, Fiona; Li, Liang

    2011-02-01

    Metabolome analysis of human cerebrospinal fluid (CSF) is challenging because of low abundance of metabolites present in a small volume of sample. We describe and apply a sensitive isotope labeling LC-MS technique for qualitative analysis of the CSF metabolome. After a CSF sample is divided into two aliquots, they are labeled by (13)C-dansyl and (12)C-dansyl chloride, respectively. The differentially labeled aliquots are then mixed and subjected to LC-MS using Fourier-transform ion cyclotron resonance mass spectrometry (FTICR MS). Dansylation offers significant improvement in the performance of chromatography separation and detection sensitivity. Moreover, peaks detected in the mass spectra can be readily analyzed for ion pair recognition and database search based on accurate mass and/or retention time information. It is shown that about 14,000 features can be detected in a 25-min LC-FTICR MS run of a dansyl-labeled CSF sample, from which about 500 metabolites can be profiled. Results from four CSF samples are compared to gauge the detectability of metabolites by this method. About 261 metabolites are commonly detected in replicate runs of four samples. In total, 1132 unique metabolite ion pairs are detected and 347 pairs (31%) matched with at least one metabolite in the Human Metabolome Database. We also report a dansylation library of 220 standard compounds and, using this library, about 85 metabolites can be positively identified. Among them, 21 metabolites have never been reported to be associated with CSF. These results illustrate that the dansylation LC-FTICR MS method can be used to analyze the CSF metabolome in a more comprehensive manner. © American Society for Mass Spectrometry, 2011

  10. Teaching Stable Two-Mirror Resonators through the Fractional Fourier Transform

    Science.gov (United States)

    Moreno, Ignacio; Garcia-Martinez, Pascuala; Ferreira, Carlos

    2010-01-01

    We analyse two-mirror resonators in terms of their fractional Fourier transform (FRFT) properties. We use the basic ABCD ray transfer matrix method to show how the resonator can be regarded as the cascade of two propagation-lens-propagation FRFT systems. Then, we present a connection between the geometric properties of the resonator (the g…

  11. Molecular formulae of marine and terrigenous dissolved organic matter detected by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry

    Science.gov (United States)

    Koch, Boris P.; Witt, Matthias; Engbrodt, Ralph; Dittmar, Thorsten; Kattner, Gerhard

    2005-07-01

    The chemical structure of refractory marine dissolved organic matter (DOM) is still largely unknown. Electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR-MS) was used to resolve the complex mixtures of DOM and provide valuable information on elemental compositions on a molecular scale. We characterized and compared DOM from two sharply contrasting aquatic environments, algal-derived DOM from the Weddell Sea (Antarctica) and terrigenous DOM from pore water of a tropical mangrove area in northern Brazil. Several thousand molecular formulas in the mass range of 300-600 Da were identified and reproduced in element ratio plots. On the basis of molecular elemental composition and double-bond equivalents (DBE) we calculated an average composition for marine DOM. O/C ratios in the marine samples were lower (0.36 ± 0.01) than in the mangrove pore-water sample (0.42). A small proportion of chemical formulas with higher molecular mass in the marine samples were characterized by very low O/C and H/C ratios probably reflecting amphiphilic properties. The average number of unsaturations in the marine samples was surprisingly high (DBE = 9.9; mangrove pore water: DBE = 9.4) most likely due to a significant contribution of carbonyl carbon. There was no significant difference in elemental composition between surface and deep-water DOM in the Weddell Sea. Although there were some molecules with unique marine elemental composition, there was a conspicuous degree of similarity between the terrigenous and algal-derived end members. Approximately one third of the molecular formulas were present in all marine as well as in the mangrove samples. We infer that different forms of microbial degradation ultimately lead to similar structural features that are intrinsically refractory, independent of the source of the organic matter and the environmental conditions where degradation took place.

  12. Monitoring wine aging with Fourier transform infrared spectroscopy (FT-IR

    Directory of Open Access Journals (Sweden)

    Basalekou Marianthi

    2015-01-01

    Full Text Available Oak wood has commonly been used in wine aging but recently other wood types such as Acacia and Chestnut, have attracted the interest of the researchers due to their possible positive contribution to wine quality. However, only the use of oak and chestnut woods is approved by the International Enological Codex of the International Organisation of Vine and Wine. In this study Fourier Transform (FT-mid-infrared spectroscopy combined with Discriminant Analysis was used to differentiate wines aged in barrels made from French oak, American oak, Acacia and Chestnut and in tanks with oak chips, over a period of 12 months. Two red (Mandilaria, Kotsifali and two white (Vilana, Dafni native Greek grape varieties where used to produce four wines. The Fourier Transform Infrared (FT-IR spectra of the samples were recorded on a Zinc Selenide (ZnSe window after incubation at 40 °C for 30 min. A complete differentiation of the samples according to both the type of wood used and the contact time was achieved based on their FT-IR spectra.

  13. Application of fast Fourier transform in thermo-magnetic convection analysis

    International Nuclear Information System (INIS)

    Pyrda, L

    2014-01-01

    Application of Fast Fourier Transform in thermo-magnetic convection is reported. Cubical enclosure filled with paramagnetic fluid heated from below and placed in the strong magnetic field gradients was investigated. The main aim of study was connected with identification of flow types, especially transition to turbulence. For this purpose the Fast Fourier Transform (FFT) analysis was applied. It was followed by the heat transfer characteristic for various values of magnetic induction gradient. The analysis was done at two Rayleigh numbers 7.89·10 5 and 1.86·10 6 with thermo-magnetic Rayleigh numbers up to 1.8·10 8 and 4.5·10 8 respectively. The presented results clearly indicate flow types and also demonstrate augmented heat transfer in dependence on magnetic induction gradient. Detailed analysis of flow transition to turbulent state was compared with transition line for natural convection reported in literature. The transition to turbulence in the case of thermo-magnetic convection of paramagnetic fluid was in very good agreement with transition in the case of natural convection.

  14. Teaching stable two-mirror resonators through the fractional Fourier transform

    International Nuclear Information System (INIS)

    Moreno, Ignacio; Garcia-Martinez, Pascuala; Ferreira, Carlos

    2010-01-01

    We analyse two-mirror resonators in terms of their fractional Fourier transform (FRFT) properties. We use the basic ABCD ray transfer matrix method to show how the resonator can be regarded as the cascade of two propagation-lens-propagation FRFT systems. Then, we present a connection between the geometric properties of the resonator (the g parameters) and those of the equivalent FRFT systems (the FRFT order and scaling parameters). Expressions connecting Gaussian beam q-transformation with FRFT parameters are derived. In particular, we show that the beam waist of the resonator's mode is located at the plane leading to two FRFT subsystems with equal scaling parameter which, moreover, coincides with the mode Rayleigh range. Finally we analyse the resonator's stability diagram in terms of the fractional orders of each FRFT subsystem, and the round trip propagation. The presented analysis represents an interesting link between two topics (optical resonators and Fourier optics) usually covered in optics and photonics courses at university level, which can be useful to teach and connect the principles of these subjects.

  15. Fourier transform infrared and fluorescence spectroscopy for analysis of vegetable oils

    Directory of Open Access Journals (Sweden)

    Nigri S.

    2013-09-01

    Full Text Available Fourier transform infrared (FTIR and fluorescence spectroscopy, combined with chemometric approaches have been developed to analysis of extra virgin olive oil adulterated with pomace olive oil. The measurements were made on pure vegetable oils: extra virgin oil, pomace olive oil and that adulterated with varying concentration of pomace olive oil. Today, the application of FTIR spectroscopy has increased in food studied, and particularly has become a powerful analytical tool in the study of edible oils and fats. The spectral regions where the variations were observed chosen for developing models and cross validation was used. The synchronous fluorescence spectrometry takes advantage of the hardware capability to vary both the excitation and emission wavelengths during the analysis with constant wavelength difference is maintained between the two. The region between 300 and 400 nm is attributed to the tocopherols and phenols, the derivatives of vitamin E are associated with the region 400–600 nm and the bands in the region of 600–700 nm are attributed to the chlorophyll and peophytin pigments. The results presented in this study suggest that FTIR and fluorescence may be a useful tool for analysis and detecting adulteration of extra virgin olive oil with pomace oil.

  16. A practical Hadamard transform spectrometer for astronomical application

    Science.gov (United States)

    Tai, M. H.

    1977-01-01

    The mathematical properties of Hadamard matrices and their application to spectroscopy are discussed. A comparison is made between Fourier and Hadamard transform encoding in spectrometry. The spectrometer is described and its laboratory performance evaluated. The algorithm and programming of inverse transform are given. A minicomputer is used to recover the spectrum.

  17. 3D spectral imaging with synchrotron Fourier transform infrared spectro-microtomography

    Science.gov (United States)

    Michael C. Martin; Charlotte Dabat-Blondeau; Miriam Unger; Julia Sedlmair; Dilworth Y. Parkinson; Hans A. Bechtel; Barbara Illman; Jonathan M. Castro; Marco Keiluweit; David Buschke; Brenda Ogle; Michael J. Nasse; Carol J. Hirschmugl

    2013-01-01

    We report Fourier transform infrared spectro-microtomography, a nondestructive three-dimensional imaging approach that reveals the distribution of distinctive chemical compositions throughout an intact biological or materials sample. The method combines mid-infrared absorption contrast with computed tomographic data acquisition and reconstruction to enhance chemical...

  18. Fourier-transform imaging of cotton and botanical and field trash mixtures

    Science.gov (United States)

    Botanical and field cotton trash comingled with cotton lint can greatly reduce the marketability and quality of cotton. Trash can be found comingled with cotton lint during harvesting, ginning, and processing, thus this study is of interest. Attenuated Total Reflectance-Fourier Transform Infrared (A...

  19. Solving singular convolution equations using the inverse fast Fourier transform

    Czech Academy of Sciences Publication Activity Database

    Krajník, E.; Montesinos, V.; Zizler, P.; Zizler, Václav

    2012-01-01

    Roč. 57, č. 5 (2012), s. 543-550 ISSN 0862-7940 R&D Projects: GA AV ČR IAA100190901 Institutional research plan: CEZ:AV0Z10190503 Keywords : singular convolution equations * fast Fourier transform * tempered distribution Subject RIV: BA - General Mathematics Impact factor: 0.222, year: 2012 http://www.springerlink.com/content/m8437t3563214048/

  20. Valuation of European Call Option via Inverse Fourier Transform

    Directory of Open Access Journals (Sweden)

    Rubenis Oskars

    2017-12-01

    Full Text Available Very few models allow expressing European call option price in closed form. Out of them, the famous Black- Scholes approach sets strong constraints - innovations should be normally distributed and independent. Availability of a corresponding characteristic function of log returns of underlying asset in analytical form allows pricing European call option by application of inverse Fourier transform. Characteristic function corresponds to Normal Inverse Gaussian (NIG probability density function. NIG distribution is obtained based on assumption that time series of log returns follows APARCH process. Thus, volatility clustering and leptokurtic nature of log returns are taken into account. The Fast Fourier transform based on trapezoidal quadrature is numerically unstable if a standard cumulative probability function is used. To solve the problem, a dampened cumulative probability is introduced. As a computation tool Matlab framework is chosen because it contains many effective vectorization tools that greatly enhance code readability and maintenance. The characteristic function of Normal Inverse Gaussian distribution is taken and exercised with the chosen set of parameters. Finally, the call price dependence on strike price is obtained and rendered in XY plot. Valuation of European call option with analytical form of characteristic function allows further developing models with higher accuracy, as well as developing models for some exotic options.

  1. Noise figure of amplified dispersive Fourier transformation

    International Nuclear Information System (INIS)

    Goda, Keisuke; Jalali, Bahram

    2010-01-01

    Amplified dispersive Fourier transformation (ADFT) is a powerful tool for fast real-time spectroscopy as it overcomes the limitations of traditional optical spectrometers. ADFT maps the spectrum of an optical pulse into a temporal waveform using group-velocity dispersion and simultaneously amplifies it in the optical domain. It greatly simplifies spectroscopy by replacing the diffraction grating and detector array in the conventional spectrometer with a dispersive fiber and single-pixel photodetector, enabling ultrafast real-time spectroscopic measurements. Following our earlier work on the theory of ADFT, here we study the effect of noise on ADFT. We derive the noise figure of ADFT and discuss its dependence on various parameters.

  2. Functional Fourier transforms and the loop equation

    International Nuclear Information System (INIS)

    Bershadskii, M.A.; Vaisburd, I.D.; Migdal, A.A.

    1986-01-01

    The Migdal-Makeenko momentum-space loop equation is investigated. This equation is derived from the ordinary loop equation by taking the Fourier transform of the Wilson functional. A perturbation theory is constructed for the new equation and it is proved that the action of the loop operator is determined by vertex functions which coincide with those of the previous equation. It is shown how the ghost loop arises in direct iterations of the momentum-space equation with respect to the coupling constant. A simple example is used to illustrate the mechanism of appearance of an integration in the interior loops in transition to observables

  3. A high-resolution Fourier Transform Spectrometer for planetary spectroscopy

    Science.gov (United States)

    Cruikshank, D. P.; Sinton, W. M.

    1973-01-01

    The employment of a high-resolution Fourier Transform Spectrometer (FTS) is described for planetary and other astronomical spectroscopy in conjunction with the 88-inch telescope at Mauna Kea Observatory. The FTS system is designed for a broad range of uses, including double-beam laboratory spectroscopy, infrared gas chromatography, and nuclear magnetic resonance spectroscopy. The data system is well-suited to astronomical applications because of its great speed in acquiring and transforming data, and because of the enormous storage capability of the magnetic tape unit supplied with the system. The basic instrument is outlined 2nd some of the initial results from the first attempted use on the Mauna Kea 88-inch telescope are reported.

  4. Fourier Transform Ultrasound Spectroscopy for the determination of wave propagation parameters.

    Science.gov (United States)

    Pal, Barnana

    2017-01-01

    The reported results for ultrasonic wave attenuation constant (α) in pure water show noticeable inconsistency in magnitude. A "Propagating-Wave" model analysis of the most popular pulse-echo technique indicates that this is a consequence of the inherent wave propagation characteristics in a bounded medium. In the present work Fourier Transform Ultrasound Spectroscopy (FTUS) is adopted to determine ultrasonic wave propagation parameters, the wave number (k) and attenuation constant (α) at 1MHz frequency in tri-distilled water at room temperature (25°C). Pulse-echo signals obtained under same experimental conditions regarding the exciting input signal and reflecting boundary wall of the water container for various lengths of water columns are captured. The Fast Fourier Transform (FFT) components of the echo signals are taken to compute k, α and r, the reflection constant at the boundary, using Oak Ridge and Oxford method. The results are compared with existing literature values. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Gaseous effluent monitoring and identification using an imaging Fourier transform spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Carter, M.R.; Bennett, C.L.; Fields, D.J.; Hernandez, J.

    1993-10-01

    We are developing an imaging Fourier transform spectrometer for chemical effluent monitoring. The system consists of a 2-D infrared imaging array in the focal plane of a Michelson interferometer. Individual images are coordinated with the positioning of a moving mirror in the Michelson interferometer. A three dimensional data cube with two spatial dimensions and one interferogram dimension is then Fourier transformed to produce a hyperspectral data cube with one spectral dimension and two spatial dimensions. The spectral range of the instrument is determined by the choice of optical components and the spectral range of the focal plane array. Measurements in the near UV, visible, near IR, and mid-IR ranges are possible with the existing instrument. Gaseous effluent monitoring and identification measurements will be primarily in the ``fingerprint`` region of the spectrum, ({lambda} = 8 to 12 {mu}m). Initial measurements of effluent using this imaging interferometer in the mid-IR will be presented.

  6. Renal geology (quantitative renal stone analysis) by 'Fourier transform infrared spectroscopy'.

    Science.gov (United States)

    Singh, Iqbal

    2008-01-01

    To prospectively determine the precise stone composition (quantitative analysis) by using infrared spectroscopy in patients with urinary stone disease presenting to our clinic. To determine an ideal method for stone analysis suitable for use in a clinical setting. After routine and a detailed metabolic workup of all patients of urolithiasis, stone samples of 50 patients of urolithiasis satisfying the entry criteria were subjected to the Fourier transform infrared spectroscopic analysis after adequate sample homogenization at a single testing center. Calcium oxalate monohydrate and dihydrate stone mixture was most commonly encountered in 35 (71%) followed by calcium phosphate, carbonate apatite, magnesium ammonium hexahydrate and xanthine stones. Fourier transform infrared spectroscopy allows an accurate, reliable quantitative method of stone analysis. It also helps in maintaining a computerized large reference library. Knowledge of precise stone composition may allow the institution of appropriate prophylactic therapy despite the absence of any detectable metabolic abnormalities. This may prevent and or delay stone recurrence.

  7. QUANTITATIVE FOURIER TRANSFORM INFRARED SPECTROSCOPIC INVESTIGATION OF HUMIC SUBSTANCE FUNCTIONAL GROUP COMPOSITION

    Science.gov (United States)

    Infrared (IR) spectroscopy has been widely used for the structural investigation of humic substances. Although Fourier Transform Infrared (FTIR) instrumentation has been available for sometime, relatively little work with these instruments has been reported for humic substances,...

  8. Improved method of generating bit reversed numbers for calculating fast fourier transform

    Digital Repository Service at National Institute of Oceanography (India)

    Suresh, T.

    Fast Fourier Transform (FFT) is an important tool required for signal processing in defence applications. This paper reports an improved method for generating bit reversed numbers needed in calculating FFT using radix-2. The refined algorithm takes...

  9. Spectrogram analysis of selected tremor signals using short-time Fourier transform and continuous wavelet transform

    Directory of Open Access Journals (Sweden)

    D. Seidl

    1999-06-01

    Full Text Available Among a variety of spectrogram methods Short-Time Fourier Transform (STFT and Continuous Wavelet Transform (CWT were selected to analyse transients in non-stationary tremor signals. Depending on the properties of the tremor signal a more suitable representation of the signal is gained by CWT. Three selected broadband tremor signals from the volcanos Mt. Stromboli, Mt. Semeru and Mt. Pinatubo were analyzed using both methods. The CWT can also be used to extend the definition of coherency into a time-varying coherency spectrogram. An example is given using array data from the volcano Mt. Stromboli.

  10. Random sampling of evolution time space and Fourier transform processing

    International Nuclear Information System (INIS)

    Kazimierczuk, Krzysztof; Zawadzka, Anna; Kozminski, Wiktor; Zhukov, Igor

    2006-01-01

    Application of Fourier Transform for processing 3D NMR spectra with random sampling of evolution time space is presented. The 2D FT is calculated for pairs of frequencies, instead of conventional sequence of one-dimensional transforms. Signal to noise ratios and linewidths for different random distributions were investigated by simulations and experiments. The experimental examples include 3D HNCA, HNCACB and 15 N-edited NOESY-HSQC spectra of 13 C 15 N labeled ubiquitin sample. Obtained results revealed general applicability of proposed method and the significant improvement of resolution in comparison with conventional spectra recorded in the same time

  11. The discrete Fourier transform theory, algorithms and applications

    CERN Document Server

    Sundaraajan, D

    2001-01-01

    This authoritative book provides comprehensive coverage of practical Fourier analysis. It develops the concepts right from the basics and gradually guides the reader to the advanced topics. It presents the latest and practically efficient DFT algorithms, as well as the computation of discrete cosine and Walsh-Hadamard transforms. The large number of visual aids such as figures, flow graphs and flow charts makes the mathematical topic easy to understand. In addition, the numerous examples and the set of C-language programs (a supplement to the book) help greatly in understanding the theory and

  12. Investigations of the functional states of dendritic cells under different conditioned microenvironments by Fourier transformed infrared spectroscopy.

    Science.gov (United States)

    Dong, Rong; Long, Jinhua; Xu, Xiaoli; Zhang, Chunlin; Wen, Zongyao; Li, Long; Yao, Weijuan; Zeng, Zhu

    2014-01-10

    Dendritic cells are potent and specialized antigen presenting cells, which play a crucial role in initiating and amplifying both the innate and adaptive immune responses. The dendritic cell-based vaccination against cancer has been clinically achieved promising successes. But there are still many challenges in its clinical application, especially for how to identify the functional states. The CD14+ monocytes were isolated from human peripheral blood after plastic adherence and purified to approximately 98% with cocktail immunomagnetic beads. The immature dendritic cells and mature dendritic cells were induced by traditional protocols. The resulting dendritic cells were cocultured with normal cells and cancer cells. The functional state of dendritic cells including immature dendritic cells (imDCs) and mature dendritic cells (mDCs) under different conditioned microenvironments were investigated by Fourier transformed infrared spectroscopy (FTIR) and molecular biological methods. The results of Fourier transformed infrared spectroscopy showed that the gene transcription activity and energy states of dendritic cells were specifically suppressed by tumor cells (P Fourier transformed infrared spectroscopy at given wave numbers were closely correlated with the expression levels of NF-κB (R2:0.69 and R2:0.81, respectively). Our results confirmed that the ratios of absorption intensities of Fourier transformed infrared spectroscopy at given wave numbers were positively correlated with the expression levels of NF-κB, suggesting that Fourier transformed infrared spectroscopy technology could be clinically applied to identify the functional states of dendritic cell when performing dendritic cell-based vaccination. It's significant for the simplification and standardization of dendritic cell-based vaccination clinical preparation protocols.

  13. Simple example of track finding by Fourier transform and possibilities for vector or optical processors

    International Nuclear Information System (INIS)

    Underwood, D.

    1986-01-01

    Simple examples of finding tracks by Fourier transform with filter or correlation function are presented. Possibilities for using this method in more complicated real situations and the processing times which might be achieved are discussed. The method imitates the simplest examples in the literature on optical pattern recognition and optical processing. The possible benefits of the method are in speed of processing in the optical Fourier transform wherein an entire picture is processed simultaneously. The speed of a computer vector processor may be competitive with present electro-optical devices. 2 refs., 6 figs

  14. All-optical WDM Regeneration of DPSK Signals using Optical Fourier Transformation and Phase Sensitive Amplification

    DEFF Research Database (Denmark)

    Guan, Pengyu; Røge, Kasper Meldgaard; Kjøller, Niels-Kristian

    2015-01-01

    We propose a novel all-optical WDM regeneration scheme for DPSK signals based on optical Fourier transformation and phase sensitive amplification. Phase regeneration of a WDM signal consisting of 4x10-Gbit/s phase noise degraded DPSK channels is demonstrated for the first time.......We propose a novel all-optical WDM regeneration scheme for DPSK signals based on optical Fourier transformation and phase sensitive amplification. Phase regeneration of a WDM signal consisting of 4x10-Gbit/s phase noise degraded DPSK channels is demonstrated for the first time....

  15. Application of Fourier transform to MHD flow over an accelerated plate with partial-slippage

    Directory of Open Access Journals (Sweden)

    Salman Ahmad

    2014-06-01

    Full Text Available Magneto-Hydrodynamic (MHD flow over an accelerated plate is investigated with partial slip conditions. Generalized Fourier Transform is used to get the exact solution not only for uniform acceleration but also for variable acceleration. The numerical solution is obtained by using linear finite element method in space and One-Step-θ-scheme in time. The resulting discretized algebraic systems are solved by applying geometric-multigrid approach. Numerical solutions are compared with the obtained Fourier transform results. Many interesting results related with slippage and MHD effects are discussed in detail through graphical sketches and tables. Application of Dirac-Delta function is one of the main features of present work.

  16. In situ Fourier transform infrared spectroscopy and on-line differential electrochemical mass spectrometry study of the NH3BH3 oxidation reaction on gold electrodes

    International Nuclear Information System (INIS)

    Belén Molina Concha, M.; Chatenet, Marian; Lima, Fabio H.B.; Ticianelli, Edson A.

    2013-01-01

    The ammonia borane (NH 3 BH 3 ) oxidation reaction (ABOR) was studied on gold electrodes using the rotating disk electrode (RDE) setup and coupled physical techniques: on-line differential electrochemical mass spectrometry (DEMS) and in situ Fourier transform infrared spectroscopy (FTIR). Non-negligible heterogeneous hydrolysis in the low-potential region was asserted via molecular H 2 detection. As a consequence, the number of electron exchanged per BH 3 OH − species is ca. 3 at low potential, and only reaches ca. 6 above 0.6 V vs. RHE. These figures were confirmed by Levich and Koutecki–Levich calculations using the RDE experiments data. The nature of the ABOR intermediates and products was determined using in situ FTIR. While BH 2 species were detected during the ABOR, it seems that its adsorption onto the Au electrode proceeds via the O atom, in opposition to what happens during the borohydride oxidation reaction (BOR). Therefore, it is likely that the mechanism of the ABOR differs from that of the BOR. From the whole set of data (RDE, DEMS, FTIR), a relevant reaction pathway was proposed, including competition between the BH 3 OH − heterogeneous hydrolysis and oxidation at low potential, and preponderant oxidation at higher potential. Finally, a simplified kinetic modeling accounting with this reaction pathway was proposed, which nicely fits the stationary (i vs. E) ABOR plot

  17. Attenuated Total Reflection Fourier Transform Infrared (ATR FT-IR) for Rapid Determination of Microbial Cell Lipid Content: Correlation with Gas Chromatography-Mass Spectrometry (GC-MS).

    Science.gov (United States)

    Millan-Oropeza, Aaron; Rebois, Rolando; David, Michelle; Moussa, Fathi; Dazzi, Alexandre; Bleton, Jean; Virolle, Marie-Joelle; Deniset-Besseau, Ariane

    2017-10-01

    There is a growing interest worldwide for the production of renewable oil without mobilizing agriculture lands; fast and reliable methods are needed to identify highly oleaginous microorganisms of potential industrial interest. The aim of this study was to demonstrate the relevance of attenuated total reflection (ATR) spectroscopy to achieve this goal. To do so, the total lipid content of lyophilized samples of five Streptomyces strains with varying lipid content was assessed with two classical quantitative but time-consuming methods, gas chromatography-mass spectrometry (GC-MS) and ATR Fourier transform infrared (ATR FT-IR) spectroscopy in transmission mode with KBr pellets and the fast ATR method, often questioned for its lack of reliability. A linear correlation between these three methods was demonstrated allowing the establishment of equations to convert ATR values expressed as CO/amide I ratio, into micrograms of lipid per milligram of biomass. The ATR method proved to be as reliable and quantitative as the classical GC-MS and FT-IR in transmission mode methods but faster and more reproducible than the latter since it involves far less manipulation for sample preparation than the two others. Attenuated total reflection could be regarded as an efficient fast screening method to identify natural or genetically modified oleaginous microorganisms by the scientific community working in the field of bio-lipids.

  18. Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Analysis of Large Polymerases Chain Reaction Products

    International Nuclear Information System (INIS)

    Wunschel, David S.; Pasa Tolic, Ljiljana; Feng, Bingbing; Smith, Richard D.

    2000-01-01

    We have attempted to expand the size range of PCR products that can be analyzed by electroscopy ionization (ESI) Fourier transformion cyclotron resonance (FTICR) mass spectrometry. The mass measurement accuracy obtained illustrates that a signel base substitution could be identified at the size of PCR product with a 7 tesla ESI-FTICR

  19. Simplification of gamma-ray spectral data by using Fourier transform

    International Nuclear Information System (INIS)

    Tominaga, Shoji; Nagata, Shojiro; Nayatani, Yoshinobu; Ueda, Isamu; Sasaki, Satoshi.

    1977-01-01

    A method is proposed to represent γ-ray response spectra by Fourier series for the purpose of compressing spectral data. The usefulness of the method was confirmed by applying it to a spectral library of a NaI detector. In the method, a response spectrum as a wave is described by superposition of sine (cosine) waves with low frequencies, whose coefficient parameters can be obtained by a Fast Fourier Transform program. The relation between the number of parameters and the fitting error is discussed, and as the result, it is shown that the number of parameters can be reduced to about a half. The merits and features are presented in practical application of the method to the analysis of γ-ray spectra. (auth.)

  20. An OTDM-To-WDM Converter Using Optical Fourier Transformation

    OpenAIRE

    Khin Su Myat Min; Zaw Myo Lwin; Hla Myo Tun

    2015-01-01

    We demonstrate serial-to-parallel conversion of 40 Gbps optical time division multiplexed OTDM signal to 4x10 Gbps wavelength division-multiplexed WDM individual channels by using Optical Fourier Transformation OFT method. OFT is also called time lens technique and it is implemented by the combination of dispersive fiber and phase modulation. In this research electro-optic phase modulator EOM is used as time lens. As our investigations simulation results and bit error rate BER measurements ar...

  1. Fast Fourier transformation results from gamma-ray burst profiles

    Science.gov (United States)

    Kouveliotou, Chryssa; Norris, Jay P.; Fishman, Gerald J.; Meegan, Charles A.; Wilson, Robert B.; Paciesas, W. S.

    1992-01-01

    Several gamma-ray bursts in the BATSE data have sufficiently long durations and complex temporal structures with pulses that appear to be spaced quasi-periodically. In order to test and quantify these periods we have applied fast Fourier transformations (FFT) to all these events. We have also performed cross spectral analyses of the FFT of the two extreme (high-low) energy bands in each case to determine the lead/lag of the pulses in different energies.

  2. Experimental demonstration of an OFDM receiver based on a silicon-nanophot onic discrete Fourier transform filter

    DEFF Research Database (Denmark)

    Da Ros, Francesco; Nolle, Markus; Meuer, C.

    2014-01-01

    We experimentally demonstrate the demultiplexing of 8×13.4 Gbaud OFDM-QPSK subcarriers using a silicon nanophotonic-based discrete Fourier transform (DFT) filter. All eight subcarriers showed less than 1.5 dB OSNR penalty compared to the theoretical limit.......We experimentally demonstrate the demultiplexing of 8×13.4 Gbaud OFDM-QPSK subcarriers using a silicon nanophotonic-based discrete Fourier transform (DFT) filter. All eight subcarriers showed less than 1.5 dB OSNR penalty compared to the theoretical limit....

  3. Aliasless fresnel transform image reconstruction in phase scrambling fourier transform technique by data interpolation

    International Nuclear Information System (INIS)

    Yamada, Yoshifumi; Liu, Na; Ito, Satoshi

    2006-01-01

    The signal in the Fresnel transform technique corresponds to a blurred one of the spin density image. Because the amplitudes of adjacent sampled signals have a high interrelation, the signal amplitude at a point between sampled points can be estimated with a high degree of accuracy even if the sampling is so coarse as to generate aliasing in the reconstructed images. In this report, we describe a new aliasless image reconstruction technique in the phase scrambling Fourier transform (PSFT) imaging technique in which the PSFT signals are converted to Fresnel transform signals by multiplying them by a quadratic phase term and are then interpolated using polynomial expressions to generate fully encoded signals. Numerical simulation using MR images showed that almost completely aliasless images are reconstructed by this technique. Experiments using ultra-low-field PSFT MRI were conducted, and aliasless images were reconstructed from coarsely sampled PSFT signals. (author)

  4. An algorithm for the basis of the finite Fourier transform

    Science.gov (United States)

    Santhanam, Thalanayar S.

    1995-01-01

    The Finite Fourier Transformation matrix (F.F.T.) plays a central role in the formulation of quantum mechanics in a finite dimensional space studied by the author over the past couple of decades. An outstanding problem which still remains open is to find a complete basis for F.F.T. In this paper we suggest a simple algorithm to find the eigenvectors of F.T.T.

  5. A fast Fourier transform program for the deconvolution of IN10 data

    International Nuclear Information System (INIS)

    Howells, W.S.

    1981-04-01

    A deconvolution program based on the Fast Fourier Transform technique is described and some examples are presented to help users run the programs and interpret the results. Instructions are given for running the program on the RAL IBM 360/195 computer. (author)

  6. Multicomplementary operators via finite Fourier transform

    International Nuclear Information System (INIS)

    Klimov, Andrei B; Sanchez-Soto, Luis L; Guise, Hubert de

    2005-01-01

    A complete set of d + 1 mutually unbiased bases exists in a Hilbert space of dimension d, whenever d is a power of a prime. We discuss a simple construction of d + 1 disjoint classes (each one having d - 1 commuting operators) such that the corresponding eigenstates form sets of unbiased bases. Such a construction works properly for prime dimension. We investigate an alternative construction in which the real numbers that label the classes are replaced by a finite field having d elements. One of these classes is diagonal, and can be mapped to cyclic operators by means of the finite Fourier transform, which allows one to understand complementarity in a similar way as for the position-momentum pair in standard quantum mechanics. The relevant examples of two and three qubits and two qutrits are discussed in detail

  7. Adaptive synchrosqueezing based on a quilted short-time Fourier transform

    Science.gov (United States)

    Berrian, Alexander; Saito, Naoki

    2017-08-01

    In recent years, the synchrosqueezing transform (SST) has gained popularity as a method for the analysis of signals that can be broken down into multiple components determined by instantaneous amplitudes and phases. One such version of SST, based on the short-time Fourier transform (STFT), enables the sharpening of instantaneous frequency (IF) information derived from the STFT, as well as the separation of amplitude-phase components corresponding to distinct IF curves. However, this SST is limited by the time-frequency resolution of the underlying window function, and may not resolve signals exhibiting diverse time-frequency behaviors with sufficient accuracy. In this work, we develop a framework for an SST based on a "quilted" short-time Fourier transform (SST-QSTFT), which allows adaptation to signal behavior in separate time-frequency regions through the use of multiple windows. This motivates us to introduce a discrete reassignment frequency formula based on a finite difference of the phase spectrum, ensuring computational accuracy for a wider variety of windows. We develop a theoretical framework for the SST-QSTFT in both the continuous and the discrete settings, and describe an algorithm for the automatic selection of optimal windows depending on the region of interest. Using synthetic data, we demonstrate the superior numerical performance of SST-QSTFT relative to other SST methods in a noisy context. Finally, we apply SST-QSTFT to audio recordings of animal calls to demonstrate the potential of our method for the analysis of real bioacoustic signals.

  8. Fourier transform and mean quadratic variation of Bernoulli convolution on homogeneous Cantor set

    Energy Technology Data Exchange (ETDEWEB)

    Yu Zuguo E-mail: yuzg@hotmail.comz.yu

    2004-07-01

    For the Bernoulli convolution on homogeneous Cantor set, under some condition, it is proved that the mean quadratic variation and the average of Fourier transform of this measure are bounded above and below.

  9. Vector Radix 2 × 2 Sliding Fast Fourier Transform

    Directory of Open Access Journals (Sweden)

    Keun-Yung Byun

    2016-01-01

    Full Text Available The two-dimensional (2D discrete Fourier transform (DFT in the sliding window scenario has been successfully used for numerous applications requiring consecutive spectrum analysis of input signals. However, the results of conventional sliding DFT algorithms are potentially unstable because of the accumulated numerical errors caused by recursive strategy. In this letter, a stable 2D sliding fast Fourier transform (FFT algorithm based on the vector radix (VR 2 × 2 FFT is presented. In the VR-2 × 2 FFT algorithm, each 2D DFT bin is hierarchically decomposed into four sub-DFT bins until the size of the sub-DFT bins is reduced to 2 × 2; the output DFT bins are calculated using the linear combination of the sub-DFT bins. Because the sub-DFT bins for the overlapped input signals between the previous and current window are the same, the proposed algorithm reduces the computational complexity of the VR-2 × 2 FFT algorithm by reusing previously calculated sub-DFT bins in the sliding window scenario. Moreover, because the resultant DFT bins are identical to those of the VR-2 × 2 FFT algorithm, numerical errors do not arise; therefore, unconditional stability is guaranteed. Theoretical analysis shows that the proposed algorithm has the lowest computational requirements among the existing stable sliding DFT algorithms.

  10. Simulation of micromechanical behavior of polycrystals: finite elements versus fast Fourier transforms

    International Nuclear Information System (INIS)

    Prakash, A; Lebensohn, R A

    2009-01-01

    In this work, we compare finite element and fast Fourier transform approaches for the prediction of the micromechanical behavior of polycrystals. Both approaches are full-field approaches and use the same visco-plastic single crystal constitutive law. We investigate the texture and the heterogeneity of the inter- and intragranular stress and strain fields obtained from the two models. Additionally, we also look into their computational performance. Two cases—rolling of aluminum and wire drawing of tungsten—are used to evaluate the predictions of the two models. Results from both the models are similar, when large grain distortions do not occur in the polycrystal. The finite element simulations were found to be highly computationally intensive, in comparison with the fast Fourier transform simulations. Figure 9 was corrected in this article on the 25 August 2009. The corrected electronic version is identical to the print version

  11. Advances in hyperspectral remote sensing I: The visible Fourier transform hyperspectral imager

    Directory of Open Access Journals (Sweden)

    J. Bruce Rafert

    2015-05-01

    Full Text Available We discuss early hyperspectral research and development activities during the 1990s that led to the deployment of aircraft and satellite payloads whose heritage was based on the use of visible, spatially modulated, imaging Fourier transform spectrometers, beginning with early experiments at the Florida Institute of Technology, through successful launch and deployment of the Visible Fourier Transform Hyperspectral Imager on MightySat II.1 on 19 July 2000. In addition to a brief chronological overview, we also discuss several of the most interesting optical engineering challenges that were addressed over this timeframe, present some as-yet un-exploited features of field-widened (slit-less SMIFTS instruments, and present some images from ground-based, aircraft-based and satellite-based instruments that helped provide the impetus for the proliferation and development of entire new families of instruments and countless new applications for hyperspectral imaging.

  12. Technical Note: Molecular characterization of aerosol-derived water soluble organic carbon using ultrahigh resolution electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry

    Directory of Open Access Journals (Sweden)

    R. M. Dickhut

    2008-09-01

    Full Text Available Despite the acknowledged relevance of aerosol-derived water-soluble organic carbon (WSOC to climate and biogeochemical cycling, characterization of aerosol WSOC has been limited. Electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS was utilized in this study to provide detailed molecular level characterization of the high molecular weight (HMW; m/z>223 component of aerosol-derived WSOC collected from rural sites in Virginia and New York, USA. More than 3000 peaks were detected by ESI FT-ICR MS within a m/z range of 223–600 for each sample. Approximately 86% (Virginia and 78% (New York of these peaks were assigned molecular formulas using only carbon (C, hydrogen (H, oxygen (O, nitrogen (N, and sulfur (S as elemental constituents. H/C and O/C molar ratios were plotted on van Krevelen diagrams and indicated a strong contribution of lignin-like and lipid-like compounds to the aerosol-derived WSOC samples. Approximately 1–4% of the peaks in the aerosol-derived WSOC mass spectra were classified as black carbon (BC on the basis of double bond equivalents calculated from the assigned molecular formulas. In addition, several high-magnitude peaks in the mass spectra of samples from both sites corresponded to molecular formulas proposed in previous secondary organic aerosol (SOA laboratory investigations indicating that SOAs are important constituents of the WSOC. Overall, ESI FT-ICR MS provides a level of resolution adequate for detailed compositional and source information of the HMW constituents of aerosol-derived WSOC.

  13. Beyond Naphthenic Acids: Environmental Screening of Water from Natural Sources and the Athabasca Oil Sands Industry Using Atmospheric Pressure Photoionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry.

    Science.gov (United States)

    Barrow, Mark P; Peru, Kerry M; Fahlman, Brian; Hewitt, L Mark; Frank, Richard A; Headley, John V

    2015-09-01

    There is a growing need for environmental screening of natural waters in the Athabasca region of Alberta, Canada, particularly in the differentiation between anthropogenic and naturally-derived organic compounds associated with weathered bitumen deposits. Previous research has focused primarily upon characterization of naphthenic acids in water samples by negative-ion electrospray ionization methods. Atmospheric pressure photoionization is a much less widely used ionization method, but one that affords the possibility of observing low polarity compounds that cannot be readily observed by electrospray ionization. This study describes the first usage of atmospheric pressure photoionization Fourier transform ion cyclotron resonance mass spectrometry (in both positive-ion and negative-ion modes) to characterize and compare extracts of oil sands process water, river water, and groundwater samples from areas associated with oil sands mining activities. When comparing mass spectra previously obtained by electrospray ionization and data acquired by atmospheric pressure photoionization, there can be a doubling of the number of components detected. In addition to polar compounds that have previously been observed, low-polarity, sulfur-containing compounds and hydrocarbons that do not incorporate a heteroatom were detected. These latter components, which are not amenable to electrospray ionization, have potential for screening efforts within monitoring programs of the oil sands.

  14. An OTDM-To-WDM Converter Using Optical Fourier Transformation

    Directory of Open Access Journals (Sweden)

    Khin Su Myat Min

    2015-08-01

    Full Text Available We demonstrate serial-to-parallel conversion of 40 Gbps optical time division multiplexed OTDM signal to 4x10 Gbps wavelength division-multiplexed WDM individual channels by using Optical Fourier Transformation OFT method. OFT is also called time lens technique and it is implemented by the combination of dispersive fiber and phase modulation. In this research electro-optic phase modulator EOM is used as time lens. As our investigations simulation results and bit error rate BER measurements are expressed.

  15. Transfer Function Identification Using Orthogonal Fourier Transform Modeling Functions

    Science.gov (United States)

    Morelli, Eugene A.

    2013-01-01

    A method for transfer function identification, including both model structure determination and parameter estimation, was developed and demonstrated. The approach uses orthogonal modeling functions generated from frequency domain data obtained by Fourier transformation of time series data. The method was applied to simulation data to identify continuous-time transfer function models and unsteady aerodynamic models. Model fit error, estimated model parameters, and the associated uncertainties were used to show the effectiveness of the method for identifying accurate transfer function models from noisy data.

  16. High-speed spectral domain optical coherence tomography using non-uniform fast Fourier transform

    Science.gov (United States)

    Chan, Kenny K. H.; Tang, Shuo

    2010-01-01

    The useful imaging range in spectral domain optical coherence tomography (SD-OCT) is often limited by the depth dependent sensitivity fall-off. Processing SD-OCT data with the non-uniform fast Fourier transform (NFFT) can improve the sensitivity fall-off at maximum depth by greater than 5dB concurrently with a 30 fold decrease in processing time compared to the fast Fourier transform with cubic spline interpolation method. NFFT can also improve local signal to noise ratio (SNR) and reduce image artifacts introduced in post-processing. Combined with parallel processing, NFFT is shown to have the ability to process up to 90k A-lines per second. High-speed SD-OCT imaging is demonstrated at camera-limited 100 frames per second on an ex-vivo squid eye. PMID:21258551

  17. Time lens based optical fourier transformation for advanced processing of spectrally-efficient OFDM and N-WDM signals

    DEFF Research Database (Denmark)

    Guan, Pengyu; Røge, Kasper Meldgaard; Morioka, Toshio

    2016-01-01

    We review recent progress in the use of time lens based optical Fourier transformation for advanced optical signal processing, with focus on all-optical generation, detection and format conversion of spectrally-efficient OFDM and N-WDM signals.......We review recent progress in the use of time lens based optical Fourier transformation for advanced optical signal processing, with focus on all-optical generation, detection and format conversion of spectrally-efficient OFDM and N-WDM signals....

  18. Fourier Transform Surface Plasmon Resonance of Nanodisks Embedded in Magnetic Nanorods.

    Science.gov (United States)

    Jung, Insub; Ih, Seongkeun; Yoo, Haneul; Hong, Seunghun; Park, Sungho

    2018-03-14

    In this study, we demonstrate the synthesis and application of magnetic plasmonic gyro-nanodisks (GNDs) for Fourier transform surface plasmon resonance based biodetection. Plasmonically active and magnetically responsive gyro-nanodisks were synthesized using electrochemical methods with anodized aluminum templates. Due to the unique properties of GNDs (magnetic responsiveness and surface plasmon bands), periodic extinction signals were generated under an external rotating magnetic field, which is, in turn, converted into frequency domains using Fourier transformation. After the binding of a target on GNDs, an increase in the shear force causes a shift in the frequency domain, which allows us to investigate biodetection for HA1 (the influenza virus). Most importantly, by modulating the number and the location of plasmonic nanodisks (a method for controlling the hydrodynamic forces by rationally designing the nanomaterial architecture), we achieved enhanced biodetection sensitivity. We expect that our results will contribute to improved sensing module performance, as well as a better understanding of dynamic nanoparticle systems, by harnessing the perturbed periodic fluctuation of surface plasmon bands under the modulated magnetic field.

  19. Specification of the Fast Fourier Transform algorithm as a term rewriting system

    NARCIS (Netherlands)

    Rodenburg, P.H.; Hoekzema, D.J.

    1987-01-01

    We specify an algorithm for multiplying polynomials with complex coefficients incorporating, the Fast Fourier Transform algorithm of Cooley and Tukey [CT]. The specification formalism we use is a variant of the formalism ASF described in. [BHK]. The difference with ASF is essentially a matter of

  20. Superexponentially damped Vlasov plasma oscillations in the Fourier transformed velocity space

    International Nuclear Information System (INIS)

    Sedlacek, Z.; Nocera, L.

    2002-01-01

    The Landau (exponentially) damped solutions of the Vlasov-Poisson equation Fourier transformed with respect to velocity are genuine eigenmodes corresponding to complex eigenvalues. In addition there exist solutions decaying faster than exponentially which exhibit no oscillatory behaviour. A new characterization is given of the initial conditions that give rise to these solutions together with a numerical demonstration

  1. Fourier-transform ghost imaging with pure far-field correlated thermal light

    International Nuclear Information System (INIS)

    Liu Honglin; Shen Xia; Han Shensheng; Zhu Daming

    2007-01-01

    Pure far-field correlated thermal light beams are created with phase grating, and Fourier-transform ghost imaging depending only on the far-field correlation is demonstrated experimentally. Theoretical analysis and the results of experimental investigation of this pure far-field correlated thermal light are presented. Applications which may be exploited with this imaging scheme are discussed

  2. Quantum Fourier transform, Heisenberg groups and quasi-probability distributions

    International Nuclear Information System (INIS)

    Patra, Manas K; Braunstein, Samuel L

    2011-01-01

    This paper aims to explore the inherent connection between Heisenberg groups, quantum Fourier transform (QFT) and (quasi-probability) distribution functions. Distribution functions for continuous and finite quantum systems are examined from three perspectives and all of them lead to Weyl-Gabor-Heisenberg groups. The QFT appears as the intertwining operator of two equivalent representations arising out of an automorphism of the group. Distribution functions correspond to certain distinguished sets in the group algebra. The marginal properties of a particular class of distribution functions (Wigner distributions) arise from a class of automorphisms of the group algebra of the Heisenberg group. We then study the reconstruction of the Wigner function from the marginal distributions via inverse Radon transform giving explicit formulae. We consider some applications of our approach to quantum information processing and quantum process tomography.

  3. Fourier transform infrared emission spectra of atomic rubidium: g- and h-states

    Czech Academy of Sciences Publication Activity Database

    Civiš, Svatopluk; Ferus, Martin; Kubelík, Petr; Chernov, Vladislav E.; Zanozina, Ekaterina M.

    2012-01-01

    Roč. 45, č. 17 (2012), s. 175002 ISSN 0953-4075 R&D Projects: GA AV ČR IAAX00100903 Institutional support: RVO:61388955 Keywords : Fourier transform infrared emission spectra * atomic rubidium * physical chemistry Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.031, year: 2012

  4. Principles of Fourier analysis

    CERN Document Server

    Howell, Kenneth B

    2001-01-01

    Fourier analysis is one of the most useful and widely employed sets of tools for the engineer, the scientist, and the applied mathematician. As such, students and practitioners in these disciplines need a practical and mathematically solid introduction to its principles. They need straightforward verifications of its results and formulas, and they need clear indications of the limitations of those results and formulas.Principles of Fourier Analysis furnishes all this and more. It provides a comprehensive overview of the mathematical theory of Fourier analysis, including the development of Fourier series, "classical" Fourier transforms, generalized Fourier transforms and analysis, and the discrete theory. Much of the author''s development is strikingly different from typical presentations. His approach to defining the classical Fourier transform results in a much cleaner, more coherent theory that leads naturally to a starting point for the generalized theory. He also introduces a new generalized theory based ...

  5. Application of the fractional Fourier transform to the design of LCOS based optical interconnects and fiber switches.

    Science.gov (United States)

    Robertson, Brian; Zhang, Zichen; Yang, Haining; Redmond, Maura M; Collings, Neil; Liu, Jinsong; Lin, Ruisheng; Jeziorska-Chapman, Anna M; Moore, John R; Crossland, William A; Chu, D P

    2012-04-20

    It is shown that reflective liquid crystal on silicon (LCOS) spatial light modulator (SLM) based interconnects or fiber switches that use defocus to reduce crosstalk can be evaluated and optimized using a fractional Fourier transform if certain optical symmetry conditions are met. Theoretically the maximum allowable linear hologram phase error compared to a Fourier switch is increased by a factor of six before the target crosstalk for telecom applications of -40 dB is exceeded. A Gerchberg-Saxton algorithm incorporating a fractional Fourier transform modified for use with a reflective LCOS SLM is used to optimize multi-casting holograms in a prototype telecom switch. Experiments are in close agreement to predicted performance.

  6. Quadrature detection for the separation of the signals of positive and negative ions in fourier transform ion cyclotron resonance mass spectrometry

    International Nuclear Information System (INIS)

    Schweikhard, Lutz; Drader, Jared J.; Shi, Stone D.-H.; Hendrickson, Christopher L.; Marshall, Alan G.

    2002-01-01

    Positive and negative ions may be confined simultaneously in a nested open cylindrical Malmberg-Penning trap. However, ion charge sign cannot be distinguished by conventional dipolar (linearly-polarized) detection with a single pair of opposed electrodes. Here, the signals from each of two orthogonal pairs of opposed detection electrodes are acquired simultaneously and stored as real and imaginary parts of mathematically complex data. Complex Fourier transformation yields separate spectra for positive and negative ions. For a fullerene sample, experimental quadrature detection yields C 60 + and C 60 - signals separated by ∼1440 u rather than by the mass of two electrons, ∼0.001 u in conventional dipolar detection

  7. Improving Spectral Results Using Row-by-Row Fourier Transform of Spatial Heterodyne Raman Spectrometer Interferogram.

    Science.gov (United States)

    Barnett, Patrick D; Strange, K Alicia; Angel, S Michael

    2017-06-01

    This work describes a method of applying the Fourier transform to the two-dimensional Fizeau fringe patterns generated by the spatial heterodyne Raman spectrometer (SHRS), a dispersive interferometer, to correct the effects of certain types of optical alignment errors. In the SHRS, certain types of optical misalignments result in wavelength-dependent and wavelength-independent rotations of the fringe pattern on the detector. We describe here a simple correction technique that can be used in post-processing, by applying the Fourier transform in a row-by-row manner. This allows the user to be more forgiving of fringe alignment and allows for a reduction in the mechanical complexity of the SHRS.

  8. Flat-top pulse generation by the optical Fourier transform technique for ultrahigh speed signal processing

    DEFF Research Database (Denmark)

    Palushani, Evarist; Oxenløwe, Leif Katsuo; Galili, Michael

    2009-01-01

    This paper reports on the generation of 1.6-ps fullwidth at half-maximum flat-top pulses by the optical Fourier transform technique, and the utilization of these pulses in a 320-Gb/s demultiplexing experiment. It is demonstrated how a narrow pulse having a 15-nm wide third-order super-Gaussian sp......This paper reports on the generation of 1.6-ps fullwidth at half-maximum flat-top pulses by the optical Fourier transform technique, and the utilization of these pulses in a 320-Gb/s demultiplexing experiment. It is demonstrated how a narrow pulse having a 15-nm wide third-order super...

  9. Time Lens based Optical Fourier Transformation for All-Optical Signal Processing of Spectrally-Efficient Data

    DEFF Research Database (Denmark)

    Guan, Pengyu; Røge, Kasper Meldgaard; Lillieholm, Mads

    2017-01-01

    We review recent progress in the use of time lens based optical Fourier transformation for advanced all-optical signal processing. A novel time lens based complete optical Fourier transformation (OFT) technique is introduced. This complete OFT is based on two quadratic phase-modulation stages using...... four-wave mixing (FWM), separated by a dispersive medium, which enables time-to-frequency and frequency-to-time conversions simultaneously, thus performing an exchange between the temporal and spectral profiles of the input signal. Using the proposed complete OFT, several advanced all-optical signal......, such as orthogonal frequency division multiplexing (OFDM), Nyquist wavelength-division multiplexing (Nyquist-WDM) and Nyquist optical time division multiplexing (Nyquist-OTDM) signals....

  10. Engineering Model Panchromatic Fourier Transform Spectrometer (PanFTS) Instrument for the GEO-CAPE Mission

    Data.gov (United States)

    National Aeronautics and Space Administration — The Panchromatic Fourier Transform Spectrometer (PanFTS) is an imaging spectrometer that can measure pollutants, greenhouse gases, and aerosols as called for in the...

  11. Absorption Mode FT-ICR Mass Spectrometry Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Donald F.; Kilgour, David P.; Konijnenburg, Marco; O' Connor, Peter B.; Heeren, Ronald M.

    2013-12-03

    Fourier transform ion cyclotron resonance mass spectrometry offers the highest mass resolving power for molecular imaging experiments. This high mass resolving power ensures that closely spaced peaks at the same nominal mass are resolved for proper image generation. Typically higher magnetic fields are used to increase mass resolving power. However, a gain in mass resolving power can also be realized by phase correction of the data for absorption mode display. In addition to mass resolving power, absorption mode offers higher mass accuracy and signal-to-noise ratio over the conventional magnitude mode. Here we present the first use of absorption mode for Fourier transform ion cyclotron resonance mass spectrometry imaging. The Autophaser algorithm is used to phase correct each spectrum (pixel) in the image and then these parameters are used by the Chameleon work-flow based data processing software to generate absorption mode ?Datacubes? for image and spectral viewing. Absorption mode reveals new mass and spatial features that are not resolved in magnitude mode and results in improved selected ion image contrast.

  12. Symmetries of the second-difference matrix and the finite Fourier transform

    International Nuclear Information System (INIS)

    Aguilar, A.; Wolf, K.B.

    1979-01-01

    The finite Fourier transformation is well known to diagonalize the second-difference matrix and has been thus applied extensively to describe finite crystal lattices and electric networks. In setting out to find all transformations having this property, we obtain a multiparameter class of them. While permutations and unitary scaling of the eigenvectors constitute the trivial freedom of choice common to all diagonalization processes, the second-difference matrix has a larger symmetry group among whose elements we find the dihedral manifest symmetry transformations of the lattice. The latter are nevertheless sufficient for the unique specification of eigenvectors in various symmetry-adapted bases for the constrained lattice. The free symmetry parameters are shown to lead to a complete set of conserved quantities for the physical lattice motion. (author)

  13. Copy-move forgery detection utilizing Fourier-Mellin transform log-polar features

    Science.gov (United States)

    Dixit, Rahul; Naskar, Ruchira

    2018-03-01

    In this work, we address the problem of region duplication or copy-move forgery detection in digital images, along with detection of geometric transforms (rotation and rescale) and postprocessing-based attacks (noise, blur, and brightness adjustment). Detection of region duplication, following conventional techniques, becomes more challenging when an intelligent adversary brings about such additional transforms on the duplicated regions. In this work, we utilize Fourier-Mellin transform with log-polar mapping and a color-based segmentation technique using K-means clustering, which help us to achieve invariance to all the above forms of attacks in copy-move forgery detection of digital images. Our experimental results prove the efficiency of the proposed method and its superiority to the current state of the art.

  14. 10th International Conference on Progress in Fourier Transform Spectroscopy

    CERN Document Server

    Keresztury, Gábor; Kellner, Robert

    1997-01-01

    19 plenary lectures and 203 poster papers presented at the 10th International Conference of Fourier Transform Spectroscopy in Budapest 1995 give an overview on the state-of-the art of this technology and its wide range of applications. The reader will get information on any aspects of FTS including the latest instrumental developments, e.g. in diode array detection, time resolution FTS, microscopy and spectral mapping, double modulation and two-dimensional FTS.

  15. On the raising and lowering difference operators for eigenvectors of the finite Fourier transform

    International Nuclear Information System (INIS)

    Atakishiyeva, M K; Atakishiyev, N M

    2015-01-01

    We construct explicit forms of raising and lowering difference operators that govern eigenvectors of the finite (discrete) Fourier transform. Some of the algebraic properties of these operators are also examined. (paper)

  16. VUV Fourier-Transform absorption study of the np pi (1)Pi(-)(u) nu,N

    NARCIS (Netherlands)

    Glass-Maujean, M.; Jungen, C.; Dickenson, G.D.; Ubachs, W.M.G.; de Oliveira, N.; Joyeux, D.

    2015-01-01

    Abstract The DESIRS beamline of the SOLEIL synchrotron facility, equipped with a vacuum ultraviolet Fourier-Transform spectrometer has been used to measure Q(N″)(N-N″=0) absorption transitions of the D

  17. Characterization of low molecular weight dissolved natural organic matter along the treatment trait of a waterworks using Fourier transform ion cyclotron resonance mass spectrometry.

    Science.gov (United States)

    Zhang, Haifeng; Zhang, Yahe; Shi, Quan; Ren, Shuoyi; Yu, Jianwei; Ji, Feng; Luo, Wenbin; Yang, Min

    2012-10-15

    Dissolved natural organic matter (DOM), particularly the low molecular weight DOM, can affect the performance of water treatment processes and serve as a main precursor of disinfection by-products (DBPs) during chlorination. In this study, electrospray ionization coupled to Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) was used to characterize the low molecular weight DOM along the treatment trait of a conventional drinking water treatment plant. The ESI FT-ICR MS data showed that various C, H, O-only class species were the major components in the source water. According to the van Krevelen diagram analysis, lignin- and tannin-like compounds were the most abundant components. Within an isobaric group, the DOM molecules with a high degree of oxidation (high O/C value) were preferentially removed during coagulation, while those with low degree of oxidation were found to be more reactive toward chlorine. In addition, 357 one-chlorine containing products and 199 two-chlorine containing products formed during chlorination were detected in the chlorination effluent sample at a high confidence level. The chlorinated products can be arranged into series, suggesting that they were originated from C, H, O-only precursor compounds, which were in series related by the replacement of CH(4) against oxygen. For the first time, this study explored the behavior of low molecular weight DOM along a drinking water treatment trait on the molecular level, and revealed the presence of abundant unknown chlorinated products, which are probably rich in carboxylic and phenolic groups, in drinking water. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Ions generated from uranyl nitrate solutions by electrospray ionization (ESI) and detected with Fourier transform ion-cyclotron resonance (FT-ICR) mass spectrometry.

    Science.gov (United States)

    Pasilis, Sofie; Somogyi, Arpád; Herrmann, Kristin; Pemberton, Jeanne E

    2006-02-01

    Electrospray ionization (ESI) of uranyl nitrate solutions generates a wide variety of positively and negatively charged ions, including complex adducts of uranyl ions with methoxy, hydroxy, and nitrate ligands. In the positive ion mode, ions detected by Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry are sensitive to instrumental tuning parameters such as quadrupole operating frequency and trapping time. Positive ions correspond to oligomeric uranyl nitrate species that can be characterized as having a general formula of [(UO(2))(n)(A)(m)(CH(3)OH)(s)](+) or [(UO(2))(n)(O)(A)(m)(CH(3)OH)(s)](+) with n = 1-4, m = 1-7, s = 0 or 1, and A = OH, NO(3), CH(3)O or a combination of these, although the formation of NO(3)-containing species is preferred. In the negative ion mode, complexes of the form [(UO(2))(NO(3))(m)](-) (m = 1-3) are detected, although the formation of the oxo-containing ions [(UO(2))(O)(n)(NO(3))(m)](-) (n = 1-2, m = 1-2) and the hydroxy-containing ions [(UO(2))(OH)(n)(NO(3))(m)](-) (n = 1-2, m = 0-1) are also observed. The extent of coordinative unsaturation of both positive and negative ions can be determined by ligand association/exchange and H/D exchange experiments using D(2)O and CD(3)OD as neutral reaction partners in the gas-phase. Positive ions are of varying stability and reactivity and may fragment extensively upon collision with D(2)O, CD(3)OD and N(2) in sustained off-resonance irradiation/collision-induced dissociation (SORI-CID) experiments. Electron-transfer reactions, presumably occurring during electrospray ionization but also in SORI-CID, can result in reduction of U(VI) to U(V) and perhaps even U(IV).

  19. Solution of multi-group diffusion equation in x-y-z geometry by finite Fourier transformation

    International Nuclear Information System (INIS)

    Kobayashi, Keisuke

    1975-01-01

    The multi-group diffusion equation in three-dimensional x-y-z geometry is solved by finite Fourier transformation. Applying the Fourier transformation to a finite region with constant nuclear cross sections, the fluxes and currents at the material boundaries are obtained in terms of the Fourier series. Truncating the series after the first term, and assuming that the source term is piecewise linear within each mesh box, a set of coupled equations is obtained in the form of three-point equations for each coordinate. These equations can be easily solved by the alternative direction implicit method. Thus a practical procedure is established that could be applied to replace the currently used difference equation. This equation is used to solve the multi-group diffusion equation by means of the source iteration method; and sample calculations for thermal and fast reactors show that the present method yields accurate results with a smaller number of mesh points than the usual finite difference equations. (auth.)

  20. Adaptive Filtering to Enhance Noise Immunity of Impedance and Admittance Spectroscopy: Comparison with Fourier Transformation

    Science.gov (United States)

    Stupin, Daniil D.; Koniakhin, Sergei V.; Verlov, Nikolay A.; Dubina, Michael V.

    2017-05-01

    The time-domain technique for impedance spectroscopy consists of computing the excitation voltage and current response Fourier images by fast or discrete Fourier transformation and calculating their relation. Here we propose an alternative method for excitation voltage and current response processing for deriving a system impedance spectrum based on a fast and flexible adaptive filtering method. We show the equivalence between the problem of adaptive filter learning and deriving the system impedance spectrum. To be specific, we express the impedance via the adaptive filter weight coefficients. The noise-canceling property of adaptive filtering is also justified. Using the RLC circuit as a model system, we experimentally show that adaptive filtering yields correct admittance spectra and elements ratings in the high-noise conditions when the Fourier-transform technique fails. Providing the additional sensitivity of impedance spectroscopy, adaptive filtering can be applied to otherwise impossible-to-interpret time-domain impedance data. The advantages of adaptive filtering are justified with practical living-cell impedance measurements.

  1. Novel molecular-level evidence of iodine binding to natural organic matter from Fourier transform ion cyclotron resonance mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Chen, E-mail: xuchen66@tamu.edu [Laboratory for Environmental and Oceanographic Research, Department of Marine Sciences, Texas A and M University, Building 3029, Galveston, TX 77551 (United States); Chen, Hongmei [Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, VA 23529 (United States); Sugiyama, Yuko [Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, VA 23529 (United States); University of Hyogo, 1-1-12, Shinzaike-honcho, Himeji, Hyogo 670-0092 (Japan); Zhang, Saijin; Li, Hsiu-Ping; Ho, Yi-Fang; Chuang, Chia-ying; Schwehr, Kathleen A. [Laboratory for Environmental and Oceanographic Research, Department of Marine Sciences, Texas A and M University, Building 3029, Galveston, TX 77551 (United States); Kaplan, Daniel I. [Savannah River National Laboratory, Aiken, SC 29808 (United States); Yeager, Chris [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Roberts, Kimberly A. [Savannah River National Laboratory, Aiken, SC 29808 (United States); Hatcher, Patrick G. [Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, VA 23529 (United States); Santschi, Peter H. [Laboratory for Environmental and Oceanographic Research, Department of Marine Sciences, Texas A and M University, Building 3029, Galveston, TX 77551 (United States)

    2013-04-01

    Major fractions of radioiodine ({sup 129}I) are associated with natural organic matter (NOM) in the groundwater and surface soils of the Savannah River Site (SRS). Electrospray ionization coupled to Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR-MS) was applied to elucidate the interactions between inorganic iodine species (iodide and iodate) and a fulvic acid (FA) extracted from a SRS surface soil. Iodate is likely reduced to reactive iodine species by the lignin- and tannin-like compounds or the carboxylic-rich alicyclic molecules (CRAM), during which condensed aromatics and lignin-like compounds were generated. Iodide is catalytically oxidized into reactive iodine species by peroxides, while FA is oxidized by peroxides into more aliphatic and less aromatic compounds. Only 9% of the total identified organo-iodine compounds derived from molecules originally present in the FA, whereas most were iodine binding to newly-produced compounds. The resulting iodinated molecules were distributed in three regions in the van Krevelen diagrams, denoting unsaturated hydrocarbons, lignin and protein. Moreover, characteristics of these organo-iodine compounds, such as their relatively low O/C ratios (< 0.2 or < 0.4) and yet some degree of un-saturation close to that of lignin, have multiple important environmental implications concerning possibly less sterically-hindered aromatic ring system for iodine to get access to and a lower hydrophilicity of the molecules thus to retard their migration in the natural aquatic systems. Lastly, ∼ 69% of the identified organo-iodine species contains nitrogen, which is presumably present as -NH{sub 2} or -HNCOR groups and a ring-activating functionality to favor the electrophilic substitution. The ESI-FTICR-MS technique provides novel evidence to better understand the reactivity and scavenging properties of NOM towards radioiodine and possible influence of NOM on {sup 129}I migration. Highlights: ► IO{sub 3}{sup

  2. A prototype stationary Fourier transform spectrometer for near-infrared absorption spectroscopy.

    Science.gov (United States)

    Li, Jinyang; Lu, Dan-feng; Qi, Zhi-mei

    2015-09-01

    A prototype stationary Fourier transform spectrometer (FTS) was constructed with a fiber-coupled lithium niobate (LiNbO3) waveguide Mach-Zehnder interferometer (MZI) for the purpose of rapid on-site spectroscopy of biological and chemical measurands. The MZI contains push-pull electrodes for electro-optic modulation, and its interferogram as a plot of intensity against voltage was obtained by scanning the modulating voltage from -60 to +60 V in 50 ms. The power spectrum of input signal was retrieved by Fourier transform processing of the interferogram combined with the wavelength dispersion of half-wave voltage determined for the MZI used. The prototype FTS operates in the single-mode wavelength range from 1200 to 1700 nm and allows for reproducible spectroscopy. A linear concentration dependence of the absorbance at λmax = 1451 nm for water in ethanolic solution was obtained using the prototype FTS. The near-infrared spectroscopy of solid samples was also implemented, and the different spectra obtained with different materials evidenced the chemical recognition capability of the prototype FTS. To make this prototype FTS practically applicable, work on improving its spectral resolution by increasing the maximum optical path length difference is in progress.

  3. Algorithm, applications and evaluation for protein comparison by Ramanujan Fourier transform.

    Science.gov (United States)

    Zhao, Jian; Wang, Jiasong; Hua, Wei; Ouyang, Pingkai

    2015-12-01

    The amino acid sequence of a protein determines its chemical properties, chain conformation and biological functions. Protein sequence comparison is of great importance to identify similarities of protein structures and infer their functions. Many properties of a protein correspond to the low-frequency signals within the sequence. Low frequency modes in protein sequences are linked to the secondary structures, membrane protein types, and sub-cellular localizations of the proteins. In this paper, we present Ramanujan Fourier transform (RFT) with a fast algorithm to analyze the low-frequency signals of protein sequences. The RFT method is applied to similarity analysis of protein sequences with the Resonant Recognition Model (RRM). The results show that the proposed fast RFT method on protein comparison is more efficient than commonly used discrete Fourier transform (DFT). RFT can detect common frequencies as significant feature for specific protein families, and the RFT spectrum heat-map of protein sequences demonstrates the information conservation in the sequence comparison. The proposed method offers a new tool for pattern recognition, feature extraction and structural analysis on protein sequences. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Double-resolution electron holography with simple Fourier transform of fringe-shifted holograms.

    Science.gov (United States)

    Volkov, V V; Han, M G; Zhu, Y

    2013-11-01

    We propose a fringe-shifting holographic method with an appropriate image wave recovery algorithm leading to exact solution of holographic equations. With this new method the complex object image wave recovered from holograms appears to have much less traditional artifacts caused by the autocorrelation band present practically in all Fourier transformed holograms. The new analytical solutions make possible a double-resolution electron holography free from autocorrelation band artifacts and thus push the limits for phase resolution. The new image wave recovery algorithm uses a popular Fourier solution of the side band-pass filter technique, while the fringe-shifting holographic method is simple to implement in practice. Published by Elsevier B.V.

  5. Fourier transform infrared microspectroscopy for the analysis of the biochemical composition of C. elegans worms.

    Science.gov (United States)

    Sheng, Ming; Gorzsás, András; Tuck, Simon

    2016-01-01

    Changes in intermediary metabolism have profound effects on many aspects of C. elegans biology including growth, development and behavior. However, many traditional biochemical techniques for analyzing chemical composition require relatively large amounts of starting material precluding the analysis of mutants that cannot be grown in large amounts as homozygotes. Here we describe a technique for detecting changes in the chemical compositions of C. elegans worms by Fourier transform infrared microspectroscopy. We demonstrate that the technique can be used to detect changes in the relative levels of carbohydrates, proteins and lipids in one and the same worm. We suggest that Fourier transform infrared microspectroscopy represents a useful addition to the arsenal of techniques for metabolic studies of C. elegans worms.

  6. TG/DTG, FT-ICR Mass Spectrometry, and NMR Spectroscopy Study of Heavy Fuel Oil

    KAUST Repository

    Elbaz, Ayman M.; Abdul Jameel, Abdul Gani; Hourani, Nadim; Emwas, Abdul-Hamid M.; Sarathy, Mani; Roberts, William L.

    2015-01-01

    infusion atmospheric pressure chemical ionization Fourier transform ion cyclotron resonance mass spectrometry (APCI-FTICR MS), high resolution 1H nuclear magnetic resonance (NMR), 13C NMR, and two-dimensional heteronuclear multiple bond correlation (HMBC

  7. A novel method for computation of the discrete Fourier transform over characteristic two finite field of even extension degree

    OpenAIRE

    Fedorenko, Sergei V.

    2011-01-01

    A novel method for computation of the discrete Fourier transform over a finite field with reduced multiplicative complexity is described. If the number of multiplications is to be minimized, then the novel method for the finite field of even extension degree is the best known method of the discrete Fourier transform computation. A constructive method of constructing for a cyclic convolution over a finite field is introduced.

  8. Segment density profiles of polyelectrolyte brushes determined by Fourier transform ellipsometry

    Science.gov (United States)

    Biesalski, Markus; Rühe, Jürgen; Johannsmann, Diethelm

    1999-10-01

    We describe a method for the explicit determination of the segment density profile φ(z) of surface-attached polymer brushes with multiple angle of incidence null-ellipsometry. Because the refractive index contrast between the brush layer and the solvent is weak, multiple reflections are of minor influence and the ellipsometric spectrum is closely related to the Fourier transform of the refractive index profile, thereby allowing for explicit inversion of the ellipsometric data. We chose surface-attached monolayers of polymethacrylic acid (PMAA), a weak polyelectrolyte, as a model system and determined the segment density profile of this system as a function of the pH value of the surrounding medium by the Fourier method. Complementary to the Fourier analysis, fits with error functions are given as well. The brushes were prepared on the bases of high refractive index prisms with the "grafting-from" technique. In water, the brushes swell by more than a factor of 30. The swelling increases with increasing pH because of a growing fraction of dissociated acidic groups leading to a larger electrostatic repulsion.

  9. Characterization of radiation-induced products of thymidine 3'-monophosphate and thymidylyl (3'→5') thymidine by high-performance liquid chromatography and laser-desorption fourier-transform mass spectrometry

    International Nuclear Information System (INIS)

    Yoshida, H.; Hettich, R.L.

    1994-01-01

    High-performance liquid chromatography (HPLC) and laser-desorption Fourier-transform mass spectrometry (LD FTMS) have been applied for direct measurements of radiation-induced products of nucleic acid constituents containing thymidine. Laser desorption FTMS could be used for the direct detection (neither hydrolyzed nor derivatized) of X-ray-induced decomposition products of aqueous thymidine monophosphate. After these initial experiments, a variety of hydrogenated and hydroxylated thymine standards were acquired and examined by FTMS to assist in the identification of unknown radiation-induced decomposition products of thymine-containing nucleotides and dinucleotides. To extend these studies to dinucleotides, the radiation-induced products generated by the gamma radiolysis of thymidylyl (3'→5') thymidine (TpT) were isolated by reverse-phase HPLC and identified by LD FTMS. Thymine and thymidine 3'-monophosphate were observed as the major products in this case. Several of the minor products of the HPLC profile were pooled in a single fraction and characterized simultaneously by LD FTMS. The resulting mass spectra indicated the presence of hydroxy-5,6-dihydothymidine monophosphate, 5,6-dihydrothymidine monophosphate and thymidine monophosphate, thymine glycol, hydroxy-5,6-dihydrothymine, 5-hydroxy-methyl-uracil and 5,6-dihydrothymine. The combination of HPLC purification and LD FTMS structural characterization provides a useful tool for the direct measurement of radiation-induced products of nucleotides and dinucleotides. 28 refs., 6 figs., 2 tabs

  10. Study of influence with fourier transform on long cable in measurement of fall time of DPF neutron profile

    International Nuclear Information System (INIS)

    Guo Hongsheng; Li Rurong; Tang Dengpan; Yang Gaozhao; Hu Qingyuan; Si Fenni; Zhang Jianhua; Peng Taiping

    2011-01-01

    The influence of the Fourier Transform on long cable in the measurement of fall time of DPF neutron profile is discussed by mathematical methods. The application of anti-convolution function with the Fourier Transform on long cable is analysed. The time interval between the peak time and the time that the height falls 3 orders of magnitude after peak is measured with gated-detector array system which consists of PMT (photomultiplier tube) and organic scintillation crystal. (authors)

  11. Vibrational analysis of Fourier transform spectrum of the B u )–X g ...

    Indian Academy of Sciences (India)

    improved by putting the wave number of band origins in Deslandre table. The vibrational analysis was supported by determining the Franck–Condon factor and r-centroid values. Keywords. Fourier transform spectroscopy; electronic spectrum of selenium dimer; vibrational analysis; Franck–Condon factor; r-centroid values.

  12. Applications of Fourier transform infrared spectroscopy to quality control of the epoxy matrix

    Science.gov (United States)

    Antoon, M. K.; Starkey, K. M.; Koenig, J. L.

    1979-01-01

    The object of the paper is to demonstrate the utility of Fourier transform infrared (FT-IR) difference spectra for investigating the composition of a neat epoxy resin, hardener, and catalysts. The composition and degree of cross-linking of the cured matrix is also considered.

  13. On the measurement of Wigner distribution moments in the fractional Fourier transform domain

    NARCIS (Netherlands)

    Bastiaans, M.J.; Alieva, T.

    2002-01-01

    It is shown how all global Wigner distribution moments of arbitrary order can be measured as intensity moments in the output plane of an appropriate number of fractional Fourier transform systems (generally anamorphic ones). The minimum number of (anamorphic) fractional power spectra that are needed

  14. Chemical fingerprinting of Arabidopsis using Fourier transform infrared (FT-IR) spectroscopic approaches.

    Science.gov (United States)

    Gorzsás, András; Sundberg, Björn

    2014-01-01

    Fourier transform infrared (FT-IR) spectroscopy is a fast, sensitive, inexpensive, and nondestructive technique for chemical profiling of plant materials. In this chapter we discuss the instrumental setup, the basic principles of analysis, and the possibilities for and limitations of obtaining qualitative and semiquantitative information by FT-IR spectroscopy. We provide detailed protocols for four fully customizable techniques: (1) Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS): a sensitive and high-throughput technique for powders; (2) attenuated total reflectance (ATR) spectroscopy: a technique that requires no sample preparation and can be used for solid samples as well as for cell cultures; (3) microspectroscopy using a single element (SE) detector: a technique used for analyzing sections at low spatial resolution; and (4) microspectroscopy using a focal plane array (FPA) detector: a technique for rapid chemical profiling of plant sections at cellular resolution. Sample preparation, measurement, and data analysis steps are listed for each of the techniques to help the user collect the best quality spectra and prepare them for subsequent multivariate analysis.

  15. Generation of Fourier-transform-limited heralded single photons

    International Nuclear Information System (INIS)

    U'Ren, Alfred B.; Jeronimo-Moreno, Yasser; Garcia-Gracia, Hipolito

    2007-01-01

    In this paper we study the spectral (temporal) properties of heralded single photon wave packets, triggered by the detection of an idler photon in the process of parametric down conversion. The generated single photons are studied within the framework of the chronocyclic Wigner function, from which the single photon spectral width and temporal duration can be computed. We derive specific conditions on the two-photon joint spectral amplitude which result in both pure and Fourier-transform-limited heralded single photons. Likewise, we present specific source geometries which lead to the fulfillment of these conditions and show that one of these geometries leads, for a given pump bandwidth, to the temporally shortest possible heralded single photon wave packets

  16. Fourier transform n.m.r. spectroscopy

    International Nuclear Information System (INIS)

    Shaw, D.

    1976-01-01

    This book is orientated to techniques rather than applications. The basic theory of n.m.r. is dealt with in a unified approach to the Fourier theory. The middle section of the book concentrates on the practical aspects of Fourier n.m.r., both instrumental and experimental. The final chapters briefly cover general application of n.m.r., but concentrate strongly on those areas where Fourier n.m.r. can give information which is not available by conventional techniques

  17. Fourier transform n. m. r. spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, D [Varian Ltd., Walton (UK)

    1976-01-01

    This book is orientated to techniques rather than applications. The basic theory of n.m.r. is dealt with in a unified approach to the Fourier theory. The middle section of the book concentrates on the practical aspects of Fourier n.m.r., both instrumental and experimental. The final chapters briefly cover general application of n.m.r., but concentrate strongly on those areas where Fourier n.m.r. can give information which is not available by conventional techniques.

  18. A novel recursive Fourier transform for nonuniform sampled signals: application to heart rate variability spectrum estimation.

    Science.gov (United States)

    Holland, Alexander; Aboy, Mateo

    2009-07-01

    We present a novel method to iteratively calculate discrete Fourier transforms for discrete time signals with sample time intervals that may be widely nonuniform. The proposed recursive Fourier transform (RFT) does not require interpolation of the samples to uniform time intervals, and each iterative transform update of N frequencies has computational order N. Because of the inherent non-uniformity in the time between successive heart beats, an application particularly well suited for this transform is power spectral density (PSD) estimation for heart rate variability. We compare RFT based spectrum estimation with Lomb-Scargle Transform (LST) based estimation. PSD estimation based on the LST also does not require uniform time samples, but the LST has a computational order greater than Nlog(N). We conducted an assessment study involving the analysis of quasi-stationary signals with various levels of randomly missing heart beats. Our results indicate that the RFT leads to comparable estimation performance to the LST with significantly less computational overhead and complexity for applications requiring iterative spectrum estimations.

  19. On the Elliptic Nonabelian Fourier Transform for Unipotent Representations of p-Adic Groups

    NARCIS (Netherlands)

    Ciubotaru, D.; Opdam, E.; Cogdell, J.; Kim, J.-L.; Zhu, C.-B.

    2017-01-01

    In this paper, we consider the relation between two nonabelian Fourier transforms. The first one is defined in terms of the Langlands-Kazhdan-Lusztig parameters for unipotent elliptic representations of a split p-adic group and the second is defined in terms of the pseudocoefficients of these

  20. The Kinetics of Mo(Co)6 Substitution Monitored by Fourier Transform Infrared Spectrophotometry.

    Science.gov (United States)

    Suslick, Kenneth S.; And Others

    1987-01-01

    Describes a physical chemistry experiment that uses Fourier transform (FTIR) spectrometers and microcomputers as a way of introducing students to the spectral storage and manipulation techniques associated with digitized data. It can be used to illustrate FTIR spectroscopy, simple kinetics, inorganic mechanisms, and Beer's Law. (TW)

  1. Color image cryptosystem using Fresnel diffraction and phase modulation in an expanded fractional Fourier transform domain

    Science.gov (United States)

    Chen, Hang; Liu, Zhengjun; Chen, Qi; Blondel, Walter; Varis, Pierre

    2018-05-01

    In this letter, what we believe is a new technique for optical color image encryption by using Fresnel diffraction and a phase modulation in an extended fractional Fourier transform domain is proposed. Different from the RGB component separation based method, the color image is converted into one component by improved Chirikov mapping. The encryption system is addressed with Fresnel diffraction and phase modulation. A pair of lenses is placed into the fractional Fourier transform system for the modulation of beam propagation. The structure parameters of the optical system and parameters in Chirikov mapping serve as extra keys. Some numerical simulations are given to test the validity of the proposed cryptosystem.

  2. Multi-band Image Registration Method Based on Fourier Transform

    Institute of Scientific and Technical Information of China (English)

    庹红娅; 刘允才

    2004-01-01

    This paper presented a registration method based on Fourier transform for multi-band images which is involved in translation and small rotation. Although different band images differ a lot in the intensity and features,they contain certain common information which we can exploit. A model was given that the multi-band images have linear correlations under the least-square sense. It is proved that the coefficients have no effect on the registration progress if two images have linear correlations. Finally, the steps of the registration method were proposed. The experiments show that the model is reasonable and the results are satisfying.

  3. Fourier transform infrared studies in solid egg white lysozyme

    International Nuclear Information System (INIS)

    Rivzi, T.Z.

    1994-12-01

    Fourier Transform Infrared (FTIR) Spectroscopy is the most recent addition to the arsenal of bioanalytical techniques capable of providing information about the secondary structure of proteins in a variety of environments. FTIR spectra have been obtained in solid egg white lysozyme. The spectra display the usual amide I, II and III bands. Secondary structural information obtained from the spectra after applying resolution enhancement techniques to the amide I band has been found consistent with the x-ray crystallographic data of the protein and also to the spectroscopic data of the protein in aqueous solution. (author). 17 refs, 6 figs, 2 tabs

  4. FFT-BM, Code Accuracy Evaluations with the 1D Fast Fourier Transform (FFT) Methodology

    International Nuclear Information System (INIS)

    D'Auria, F.

    2004-01-01

    1 - Description of program or function: FFT-BM is an integrated version of the programs package performing code accuracy evaluations with the 1D Fast Fourier Transform (FFT) methodology. It contains two programs: - CASEM: Takes care of the complete manipulation of data in order to evaluate the quantities through which the FFT method quantifies the code accuracy. - AAWFTO completes the evaluation of the average accuracy (AA) and related weighted frequency (WF) values in order to obtain the AAtot and WFtot values characterising the global calculation performance. 2 - Methods: The Fast Fourier Transform, or FFT, which is based on the Fourier analysis method is an optimised method for calculating the amplitude Vs frequency, of functions or experimental or computed data. In order to apply this methodology, after selecting the parameters to be analyzed, it is necessary to choose the following parameters: - number of curves (exp + calc) to be analyzed; - number of time windows to be analyzed; - sampling frequency; - cut frequency; - time begin and time end of each time window. 3 - Restrictions on the complexity of the problem: Up to 30 curves (exp + calc) and 5 time windows may be analyzed

  5. Distributed Two-Dimensional Fourier Transforms on DSPs with an Application for Phase Retrieval

    Science.gov (United States)

    Smith, Jeffrey Scott

    2006-01-01

    Many applications of two-dimensional Fourier Transforms require fixed timing as defined by system specifications. One example is image-based wavefront sensing. The image-based approach has many benefits, yet it is a computational intensive solution for adaptive optic correction, where optical adjustments are made in real-time to correct for external (atmospheric turbulence) and internal (stability) aberrations, which cause image degradation. For phase retrieval, a type of image-based wavefront sensing, numerous two-dimensional Fast Fourier Transforms (FFTs) are used. To meet the required real-time specifications, a distributed system is needed, and thus, the 2-D FFT necessitates an all-to-all communication among the computational nodes. The 1-D floating point FFT is very efficient on a digital signal processor (DSP). For this study, several architectures and analysis of such are presented which address the all-to-all communication with DSPs. Emphasis of this research is on a 64-node cluster of Analog Devices TigerSharc TS-101 DSPs.

  6. Second order oscillations of a Vlasov-Poisson plasma in the Fourier transformed space

    International Nuclear Information System (INIS)

    Sedlacek, Z.; Nocera, L.

    1991-05-01

    The Vlasov-Poisson system of equations in the Fourier-transformed velocity space is studied. At first some results of the linear theory are reformulated: in the new representation the Van Kampen eigenmodes and their adjoint are found to be ordinary functions with convenient piece-wise continuity properties. A transparent derivation is given of the free-streaming temporal echo in terms of the kinematics of wave packets in the Fourier-transformed velocity space. This analysis is further extended to include Coulomb interactions which allows to establish a connection between the echo theory, the second order oscillations of Best and the phenomenon of linear sidebands. The calculation of the time evolution of the global second order electric field is performed in detail in the case of a Maxwellian equilibrium distribution function. It is concluded that the phenomenon of linear sidebands may be properly explained in terms of the intrinsic features of the equilibrium distribution function. (author) 5 figs., 32 refs

  7. Direct application of the fast Fourier transform to open resonator calculations

    International Nuclear Information System (INIS)

    Johnson, M.M.

    1974-01-01

    It is shown that the integral equations for resonators can be written in the form of convolution integrals. A graph is given of the ratio of the time required to compute resonator eigenmodes using the fast Fourier transform (FFT) to the time required to evaluate the resonator convolution equation directly as a function of the number of mirror grid points. Computational savings made by using the FFT are discussed

  8. Fourier transform infrared spectroscopy of dental unit water line biofilm bacteria

    OpenAIRE

    Liaqat, Iram

    2009-01-01

    Fourier transform-infrared (FT-IR) spectroscopy has become an important tool for rapid analysis of complex biological samples. The infrared absorbance spectrum could be regarded as a “fingerprint” which is a feature of biochemical substances. The FT-IR spectra of fresh and stored dried samples of six bacterial isolates (Klebsiella sp., Bacillus cereus, Bacillus subtilis, Pseudomonas aeruginosa, Achromobacter xylosoxidans and Achromobacter sp.) were observed by variation in sample preparation....

  9. 1.28 Tbaud Nyquist Signal Transmission using Time-Domain Optical Fourier Transformation based Receiver

    DEFF Research Database (Denmark)

    Hu, Hao; Kong, Deming; Palushani, Evarist

    2013-01-01

    We demonstrate transmission of a 1.28-Tbaud Nyquist-OTDM signal over a record distance of 100 km with detection by time-domain optical Fourier transformation followed by FEC decoding, resulting in error-free performance for all tributaries....

  10. A Conditional Fourier-Feynman Transform and Conditional Convolution Product with Change of Scales on a Function Space II

    Directory of Open Access Journals (Sweden)

    Dong Hyun Cho

    2017-01-01

    Full Text Available Using a simple formula for conditional expectations over continuous paths, we will evaluate conditional expectations which are types of analytic conditional Fourier-Feynman transforms and conditional convolution products of generalized cylinder functions and the functions in a Banach algebra which is the space of generalized Fourier transforms of the measures on the Borel class of L2[0,T]. We will then investigate their relationships. Particularly, we prove that the conditional transform of the conditional convolution product can be expressed by the product of the conditional transforms of each function. Finally we will establish change of scale formulas for the conditional transforms and the conditional convolution products. In these evaluation formulas and change of scale formulas, we use multivariate normal distributions so that the conditioning function does not contain present positions of the paths.

  11. Vibrational analysis of Fourier transform spectrum of the B 3− u (0

    Indian Academy of Sciences (India)

    ... microwave, was recorded on BOMEM DA8 Fourier transform spectrometer at an apodized resolution of 0.035 cm-1. Vibrational constants were improved by putting the wave number of band origins in Deslandre table. The vibrational analysis was supported by determining the Franck–Condon factor and -centroid values.

  12. Multi-layer thickness determination using differential-based enhanced Fourier transforms of X-ray reflectivity data

    Energy Technology Data Exchange (ETDEWEB)

    Poust, Benjamin [Department of Materials Science and Engineering, University of California, Los Angeles, CA (United States); Northrop Grumman Space Technology, Redondo Beach, CA (United States); Sandhu, Rajinder [Northrop Grumman Space Technology, Redondo Beach, CA (United States); Goorsky, Mark [Department of Materials Science and Engineering, University of California, Los Angeles, CA (United States)

    2009-08-15

    Layer thickness determination of single and multi-layer structures is achieved using a new method for generating Fourier transforms (FTs) of X-ray reflectivity data. This enhanced Fourier analysis is compared to other techniques in the determination of AlN layer thickness deposited on sapphire. In addition to demonstrably improved results, the results also agree with thicknesses determined using simulations and TEM measurements. The effectiveness of the technique is further demonstrated using the more complicated metamorphic epitaxial multi-layer AlSb/InAs structures deposited on GaAs. The approach reported here is based upon differentiating the specular intensity with respect to the vertical reciprocal space coordinate Q{sub Z}. In general, differentiation is far more effective at removing the sloping background present in reflectivity scans than logarithmic compression alone, average subtraction alone, or other methods. When combined with any of the other enhancement techniques, however, differentiation yields distinguishable discrete Fourier transform (DFT) power spectrum peaks for even the weakest and most truncated of sloping oscillations that are present in many reflectivity scans from multi-layer structures. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  13. Generating a Square Switching Window for Timing Jitter Tolerant 160 Gb/s Demultiplexing by the Optical Fourier Transform Technique

    DEFF Research Database (Denmark)

    Oxenløwe, Leif Katsuo; Galili, Michael; Clausen, A. T:

    2006-01-01

    A square spectrum is optically Fourier transformed into a square pulse in the time domain. This is used to demultiplex a 160 Gb/s data signal with a significant increase in jitter tolerance to 2.6 ps.......A square spectrum is optically Fourier transformed into a square pulse in the time domain. This is used to demultiplex a 160 Gb/s data signal with a significant increase in jitter tolerance to 2.6 ps....

  14. A fractional Fourier transform analysis of the scattering of ultrasonic waves

    Science.gov (United States)

    Tant, Katherine M.M.; Mulholland, Anthony J.; Langer, Matthias; Gachagan, Anthony

    2015-01-01

    Many safety critical structures, such as those found in nuclear plants, oil pipelines and in the aerospace industry, rely on key components that are constructed from heterogeneous materials. Ultrasonic non-destructive testing (NDT) uses high-frequency mechanical waves to inspect these parts, ensuring they operate reliably without compromising their integrity. It is possible to employ mathematical models to develop a deeper understanding of the acquired ultrasonic data and enhance defect imaging algorithms. In this paper, a model for the scattering of ultrasonic waves by a crack is derived in the time–frequency domain. The fractional Fourier transform (FrFT) is applied to an inhomogeneous wave equation where the forcing function is prescribed as a linear chirp, modulated by a Gaussian envelope. The homogeneous solution is found via the Born approximation which encapsulates information regarding the flaw geometry. The inhomogeneous solution is obtained via the inverse Fourier transform of a Gaussian-windowed linear chirp excitation. It is observed that, although the scattering profile of the flaw does not change, it is amplified. Thus, the theory demonstrates the enhanced signal-to-noise ratio permitted by the use of coded excitation, as well as establishing a time–frequency domain framework to assist in flaw identification and classification. PMID:25792967

  15. Application of Fractional Fourier Transform to Moving Target Indication via Along-Track Interferometry

    Directory of Open Access Journals (Sweden)

    Chiu Shen

    2005-01-01

    Full Text Available A relatively unknown yet powerful technique, the so-called fractional Fourier transform (FrFT, is applied to SAR along-track interferometry (SAR-ATI in order to estimate moving target parameters. By mapping a target's signal onto a fractional Fourier axis, the FrFT permits a constant-velocity target to be focused in the fractional Fourier domain thereby affording orders of magnitude improvement in SCR. Moving target velocity and position parameters are derived and expressed in terms of an optimum fractional angle and a measured fractional Fourier position , allowing a target to be accurately repositioned and its velocity components computed without actually forming an SAR image. The new estimation algorithm is compared with the matched filter bank approach, showing some of the advantages of the FrFT method. The proposed technique is applied to the data acquired by the two-aperture CV580 airborne radar system configured in its along-track mode. Results show that the method is effective in estimating target velocity and position parameters.

  16. The Fourier transform method for infinite medium resonance absorption problems

    International Nuclear Information System (INIS)

    Menon, S.V.G.; Sahni, D.C.

    1978-01-01

    A new method, using Fourier transforms, is developed for solving the integral equation of slowing down of neutrons in the resonance region. The transformations replace the slowing down equation with a discontinuous kernel by an integral equation with a continuous kernel over the interval (-infinity, infinity). Further the Doppler broadened line shape functions have simple analytical representations in the transform variable. In the limit of zero temperature, the integral equation reduces to a second order differential equation. Accurate expressions for the zero temperature resonance integrals are derived, using the WKB method. In general, the integral equation is seen to be amenable to solution by Ganss-Hermite quadrature formule. Doppler coefficients of 238 U resonances are given and compared with Monte Carlo calculations. The method is extended to include the effect of interference between neighbouring resonances of an absorber. For the case of two interfering resonances the slowing down equation is transformed to the coupled integral equations that are amenable to solution by methods indicated earlier. Numerical results presented for the low lying thorium-232 doublet show that the Doppler coefficients of the resonances are reduced considerably because of the overlap between them. (author)

  17. Fourier-Laplace transform of irreducible regular differential systems on the Riemann sphere

    International Nuclear Information System (INIS)

    Sabbah, C

    2004-01-01

    It is shown that the Fourier-Laplace transform of an irreducible regular differential system on the Riemann sphere underlies a polarizable regular twistor D-module if one considers only the part at finite distance. The associated holomorphic bundle defined away from the origin of the complex plane is therefore equipped with a natural harmonic metric having a tame behaviour near the origin

  18. X-ray Fourier-transform holographic microscope

    International Nuclear Information System (INIS)

    Haddad, W.S.; Cullen, D.; Solem, J.C.; Boyer, K.; Rhodes, C.K.

    1988-01-01

    The properties of an x-ray Fourier-transform holographic instrument suitable for imaging hydrated biological samples are described. Recent advances in coherent x-ray source technology are making diffraction-limited holograms of microscopic structures, with corresponding high spatial resolution, a reality. A high priority application of snapshot x-ray holography is the study of microscopic biological structures in the hydrated living state. X-rays offer both high resolution and high contrast for important structures within living organisms, thereby rendering unnecessary the staining of specimens, essential for optical and electron microscopy. If the wavelength is properly chosen. Furthermore, the snapshot feature, arising from picosecond or subpicosecond exposure times, eliminates blurring occurring from either thermal heating or normal biological activity of the sample. Finally, with sufficiently high photon fluxes, such as those available from x-ray lasers, the x-ray snapshot can be accomplished with a single pulse, thereby yielding complete three-dimensional information on a sample having normal biological integrity at the moment of exposure. 10 refs., 6 figs

  19. Rotor-System Log-Decrement Identification Using Short-Time Fourier-Transform Filter

    OpenAIRE

    Li, Qihang; Wang, Weimin; Chen, Lifang; Sun, Dan

    2015-01-01

    With the increase of the centrifugal compressor capability, such as large scale LNG and CO2 reinjection, the stability margin evaluation is crucial to assure the compressor work in the designed operating conditions in field. Improving the precision of parameter identification of stability is essential and necessary as well. Based on the time-varying characteristics of response vibration during the sine-swept process, a short-time Fourier transform (STFT) filter was introduced to increase the ...

  20. Computing exact Fourier series coefficients of IC rectilinear polygons from low-resolution fast Fourier coefficients

    Science.gov (United States)

    Scheibler, Robin; Hurley, Paul

    2012-03-01

    We present a novel, accurate and fast algorithm to obtain Fourier series coefficients from an IC layer whose description consists of rectilinear polygons on a plane, and how to implement it using off-the-shelf hardware components. Based on properties of Fourier calculus, we derive a relationship between the Discrete Fourier Transforms of the sampled mask transmission function and its continuous Fourier series coefficients. The relationship leads to a straightforward algorithm for computing the continuous Fourier series coefficients where one samples the mask transmission function, compute its discrete Fourier transform and applies a frequency-dependent multiplicative factor. The algorithm is guaranteed to yield the exact continuous Fourier series coefficients for any sampling representing the mask function exactly. Computationally, this leads to significant saving by allowing to choose the maximal such pixel size and reducing the fast Fourier transform size by as much, without compromising accuracy. In addition, the continuous Fourier series is free from aliasing and follows closely the physical model of Fourier optics. We show that in some cases this can make a significant difference, especially in modern very low pitch technology nodes.

  1. Analysis of tokamak plasma confinement modes using the fast Fourier transformation

    International Nuclear Information System (INIS)

    Mirmoeini, S.R.; Salar Elahi, A.; Ghoranneviss, M.

    2016-01-01

    The Fourier analysis is a satisfactory technique for detecting plasma confinement modes in tokamaks. The confinement mode of tokamak plasma was analysed using the fast Fourier transformation (FFT). For this purpose, we used the data of Mirnov coils that is one of the identifying tools in the IR-T1 tokamak, with and without external field (electric biasing), and then compared it with each other. After the Fourier analysis of Mirnov coil data, the diagram of power spectrum density was depicted in different angles of Mirnov coils in the 'presence of external field' as well as in the 'absence of external field'. The power spectrum density (PSD) interprets the manner of power distribution of a signal with frequency. In this article, the number of plasma modes and the safety factor q were obtained by using the mode number of q = m/n (m is the mode number). The maximum MHD activity was obtained in 30-35 kHz frequency, using the density of the energy spectrum. In addition, the number of different modes across 0-35 ms time was compared with each other in the presence and absence of the external field. (author)

  2. Seismic Shear Energy Reflection By Radon-Fourier Transform

    Directory of Open Access Journals (Sweden)

    Malik Umairia

    2016-01-01

    Full Text Available Seismic waves split in an anisotropic medium, instead of rotating horizontal component to principal direction, Radon-Fourier is derived to observe the signature of shear wave reflection. Synthetic model with fracture is built and discretized using finite difference scheme for spatial and time domain. Common depth point (CDP with single shot gives traces and automatic gain is preprocessed before Radon Transform (RT, a filtering technique gives radon domain. It makes easier to observe fractures at specific incidence and improves its quality in some way by removing the noise. A comparison of synthetic data and BF-data is performed on the basis of root means square error (RMS values. The RMS error is minimum at the 10th trace in radon domain.

  3. Three dimensional implementation of anisotropy corrected fast fourier transform dose calculation around brachytherapy seeds

    International Nuclear Information System (INIS)

    Kyeremeh, P.O.

    2011-01-01

    Current-available brachytherapy dose computation algorithms ignore heterogeneities such as tissue-air interfaces, shielded gynaecological colpostats, and tissue-composition variations in source implants despite dose computation errors as large as 40%. A convolution kernel, which takes into consideration anisotropy of the dose distribution around a brachytherapy source, and to compute dose in the presence of tissue and applicator heterogeneities, has been established. Resulting from the convolution kernel are functions with polynomial and exponential terms. the solution to the convolution integral was represented by the Fast Fourier transform. The Fast Fourier transform has shown enough potency in accounting for errors due to these heterogeneities and the versatility of this Fast Fourier transform is evident from its capability of switching in between fields. Thus successful procedures in external beam could be adopted in brachytherapy to a yield similar effect. A dose deposition kernel was developed for a 64x64x64 matrix size with wrap around ordering and convoluted with the distribution of the sources in 3D. With MatLab's inverse Fast Fourier transform, dose rate distribution for a given array of interstitial sources, typical of brachytherapy was calculated. The shape of the dose rate distribution peaks appeared comparable with the output expected from computerized treatment planning systems for brachytherapy. Subsequently, the study confirmed the speed and accuracy of dose computation using the FFT convolution as well juxtaposed. Although, dose rate peaks from both the FFT convolution and the TPS(TG43) did not compare quantitatively, which was mainly due to the TPS(TG43) initiation computations from the origin (0,0,0) unlike the FFT convolution which uses sampling points; N=1,2,3..., there is a strong basis for establishing parity since the dose rate peaks compared qualitatively. With both modes compared, the discrepancies in the dose rates ranged between 3.6% to

  4. Extremely compact formulas for the Fourier transform of a product of two-centre Slater-type orbitals

    International Nuclear Information System (INIS)

    Vukovic, T; Dmitrovic, S

    2010-01-01

    A compact formula for the Fourier transform of a product of Slater-type orbitals on different centres is derived. The integral is reduced to a finite one-dimensional integration over non-oscillatory hypergeometric functions of type 1 F 2 (x;y;z). The formula is valid for all quantum numbers and does not involve the reduced Bessel functions that are usually used to evaluate these integrals. Reduced formulas are calculated for some special directions in the reciprocal space. Also, some useful identities for the Fourier transforms of a product of Slater-type orbitals with correlated sets of parameters are obtained. In order to illustrate simple and efficient use of the presented results, we have applied them to graphene.

  5. 16 channel WDM regeneration in a single phase-sensitive amplifier through optical Fourier transformation

    DEFF Research Database (Denmark)

    Guan, Pengyu; Da Ros, Francesco; Lillieholm, Mads

    2016-01-01

    We demonstrate simultaneous phase regeneration of 16-WDM DPSK channels using optical Fourier transformation and a single phase-sensitive amplifier. The BERs of 16-WDM×10-Gbit/s phase noise degraded DPSK signals are improved by 0.4-1.3 orders of magnitude...

  6. Study of cancer cell lines with Fourier transform infrared (FTIR)/vibrational absorption (VA) spectroscopy

    DEFF Research Database (Denmark)

    Uceda Otero, E. P.; Eliel, G. S. N.; Fonseca, E. J. S.

    2013-01-01

    In this work we have used Fourier transform infrared (FTIR) / vibrational absorption (VA) spectroscopy to study two cancer cell lines: the Henrietta Lacks (HeLa) human cervix carcinoma and 5637 human bladder carcinoma cell lines. Our goal is to experimentally investigate biochemical changes...

  7. Fractional Fourier transform for confluent hypergeometric beams

    International Nuclear Information System (INIS)

    Tang, Bin; Jiang, Chun; Zhu, Haibin

    2012-01-01

    Based on the definition of the fractional Fourier transform (FRFT) in the cylindrical coordinate system, the propagation properties of a new family of paraxial laser beams named confluent hypergeometric (HyG) beams, of which intensity profile is similar to that for the Bessel modes, passing through FRFT optical systems have been studied in detail by some typical numerical examples. The results indicate that the normalized intensity distribution of a HyG beam in the FRFT plane is closely related to not only the fractional order p but also the beam parameters m,n, and focal length f. -- Highlights: ► We study the propagation of a HyG beam through FRFT optical systems. ► The intensity of the beam in the FRFT plane is closely related to some parameters. ► We can control the properties of HyG beams by properly choosing the parameters.

  8. Fast data reconstructed method of Fourier transform imaging spectrometer based on multi-core CPU

    Science.gov (United States)

    Yu, Chunchao; Du, Debiao; Xia, Zongze; Song, Li; Zheng, Weijian; Yan, Min; Lei, Zhenggang

    2017-10-01

    Imaging spectrometer can gain two-dimensional space image and one-dimensional spectrum at the same time, which shows high utility in color and spectral measurements, the true color image synthesis, military reconnaissance and so on. In order to realize the fast reconstructed processing of the Fourier transform imaging spectrometer data, the paper designed the optimization reconstructed algorithm with OpenMP parallel calculating technology, which was further used for the optimization process for the HyperSpectral Imager of `HJ-1' Chinese satellite. The results show that the method based on multi-core parallel computing technology can control the multi-core CPU hardware resources competently and significantly enhance the calculation of the spectrum reconstruction processing efficiency. If the technology is applied to more cores workstation in parallel computing, it will be possible to complete Fourier transform imaging spectrometer real-time data processing with a single computer.

  9. Mix ratio measurements of pozzolanic blends by Fourier transform infrared-attenuated total reflectance method

    International Nuclear Information System (INIS)

    Rebagay, T.V.; Dodd, D.A.

    1992-07-01

    The disposal of low-level radioactive liquid wastes at the Hanford Site near Richland, Washington, involves mixing the wastes with pozzolanic grout-forming solid blends. Checking the quality of each blend component and its mix ratio will ensure processibility of the blend and the long-term performance of the resulting waste grout. In earlier work at Hanford laboratories, Fourier transform infrared-transmission method (FTIR-TR) using KBr pellet was applied successfully in the analysis of blends consisting of cement, fly ash, and clays. This method involves time-consuming sample preparation resulting in slow turnaround for repetitive sampling. Because reflection methods do not require elaborate sample preparation, they have the potential to reduce turnaround analysis time. Neat samples may be examined making these methods attractive for quality control. This study investigates the capability of Fourier transform infrared-attenuated total reflectance method (FTIR-ATR) to analyze pozzolanic blends

  10. Flow-through Fourier transform infrared sensor for total hydrocarbons determination in water.

    Science.gov (United States)

    Pérez-Palacios, David; Armenta, Sergio; Lendl, Bernhard

    2009-09-01

    A new flow-through Fourier transform infrared (FT-IR) sensor for oil in water analysis based on solid-phase spectroscopy on octadecyl (C18) silica particles has been developed. The C18 non-polar sorbent is placed inside the sensor and is able to retain hydrocarbons from water samples. The system does not require the use of chlorinated solvents, reducing the environmental impact, and the minimal sample handling stages serve to ensure sample integrity whilst reducing exposure of the analyst to any toxic hydrocarbons present within the samples. Fourier transform infrared (FT-IR) spectra were recorded by co-adding 32 scans at a resolution of 4 cm(-1) and the band located at 1462 cm(-1) due to the CH(2) bending was integrated from 1475 to 1450 cm(-1) using a baseline correction established between 1485 and 1440 cm(-1) using the areas as analytical signal. The technique, which provides a limit of detection (LOD) of 22 mg L(-1) and a precision expressed as relative standard deviation (RSD) lower than 5%, is considerably rapid and allows for a high level of automation.

  11. Fourier-Transform Raman Spectroscopy of Polymers Caractérisation de polymères par spectroscopie Raman à transformée de Fourier

    Directory of Open Access Journals (Sweden)

    Siesler H. W.

    2006-11-01

    Full Text Available The recent extension of the Fourier-Transform (FT technique to the Raman effect has launched Raman spectroscopy into a new era of polymer chemical and physical applications. Thus, the increase in signal-to-noise ratio and the improvement in time resolution have largely enhanced the potential of FT-Raman spectroscopy for analytical applications, the characterization of time-dependent phenomena and the on-line combination with other techniques. Primarily the suppression of fluorescence by shifting the excitation line to the near-infrared (NIR region has contributed to the fast acceptance as an industrial routine tool. Furthermore, the application of fiber optics has opened up the areas of process-control and remote sensing. Les applications de la spectroscopie Raman dans le domaine des polymères sont entrées dans une ère nouvelle, grâce aux récents développements de la technique à transformée de Fourier avec excitation dans le proche infrarouge. L'augmentation du rapport signal sur bruit et l'amélioration de la résolution temporelle ont fortement renforcé les potentialités de la technique en ce qui concerne les applications analytiques, la caractérisation de phénomènes qui dépendent du temps et le couplage en ligne avec d'autres techniques. La suppression du phénomène de fluorescence par déplacement de la longueur d'onde de l'excitatrice dans le proche infrarouge a contribué à l'intégration rapide de l'outil en site industriel. L'emploi de fibres optiques a permis l'accroissement des applications dans le domaine du contrôle des procédés et d'analyser à distance.

  12. Optical Two Dimensional Fourier Transform Spectroscopy of Layered Metal Dichalcogenides

    Science.gov (United States)

    Dey, P.; Paul, J.; Stevens, C. E.; Kovalyuk, Z. D.; Kudrynskyi, Z. R.; Romero, A. H.; Cantarero, A.; Hilton, D. J.; Shan, J.; Karaiskaj, D.; Z. D. Kovalyuk; Z. R. Kudrynskyi Collaboration; A. H. Romero Collaboration; A. Cantarero Collaboration; D. J. Hilton Collaboration; J. Shan Collaboration

    2015-03-01

    Nonlinear two-dimensional Fourier transform (2DFT) measurements were used to study the mechanism of excitonic dephasing and probe the electronic structure of the excitonic ground state in layered metal dichalcogenides. Temperature-dependent 2DFT measurements were performed to probe exciton-phonon interactions. Excitation density dependent 2DFT measurements reveal exciton-exciton and exciton-carrier scattering, and the lower limit for the homogeneous linewidth of excitons on positively and negatively doped samples. U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Award DE-SC0012635.

  13. Fourier techniques in X-ray timing

    NARCIS (Netherlands)

    van der Klis, M.

    1988-01-01

    Basic principles of Fourier techniques often used in X-ray time series analysis are reviewed. The relation between the discrete Fourier transform and the continuous Fourier transform is discussed to introduce the concepts of windowing and aliasing. The relation is derived between the power spectrum

  14. Vector frequency-comb Fourier-transform spectroscopy for characterizing metamaterials

    International Nuclear Information System (INIS)

    Ganz, T; Brehm, M; Von Ribbeck, H G; Keilmann, F; Van der Weide, D W

    2008-01-01

    We determine infrared transmission amplitude and phase spectra of metamaterial samples at well-defined incidence and polarization with a vector ('asymmetric') frequency-comb Fourier-transform spectrometer (c-FTS) that uses no moving elements. The metamaterials are free-standing metallic hole arrays; we study their resonances in the 7-13 μm and 100-1000 μm wavelength regions due both to interaction with bulk waves (Wood anomaly) and with leaky surface plasmon polaritons (near-unity transmittance, coupling features and dispersion). Such complex-valued transmission and reflection spectra could be used to compute a metamaterial's complex dielectric function directly, as well as its magnetic and magneto-optical permeability functions.

  15. Radiometric and signal-to-noise ratio properties of multiplex dispersive spectrometry

    International Nuclear Information System (INIS)

    Barducci, Alessandro; Guzzi, Donatella; Lastri, Cinzia; Nardino, Vanni; Marcoionni, Paolo; Pippi, Ivan

    2010-01-01

    Recent theoretical investigations have shown important radiometric disadvantages of interferential multiplexing in Fourier transform spectrometry that apparently can be applied even to coded aperture spectrometers. We have reexamined the methods of noninterferential multiplexing in order to assess their signal-to-noise ratio (SNR) performance, relying on a theoretical modeling of the multiplexed signals. We are able to show that quite similar SNR and radiometric disadvantages affect multiplex dispersive spectrometry. The effect of noise on spectral estimations is discussed.

  16. Characterization of ceramic matrix composite degradation using Fourier transform infrared spectroscopy

    Science.gov (United States)

    Henry, Christine; Criner, Amanda Keck; Imel, Megan; King, Derek

    2018-04-01

    Data collected with a handheld Fourier Transform Infrared (FTIR) device is analyzed and considered as a useful method for detecting and quantifying oxidation on the surface of ceramic matrix composite (CMC) materials. Experiments examine silicon carbide (SiC) coupons, looking for changes in chemical composition before and after thermal exposure. Using mathematical, physical and statistical models for FTIR reflectance data, this research seeks to quantify any detected spectral changes as an indicator of surface oxidation on the CMC coupon.

  17. Use of Fourier transforms for asynoptic mapping: Applications to the Upper Atmosphere Research Satellite microwave limb sounder

    Science.gov (United States)

    Elson, Lee S.; Froidevaux, Lucien

    1993-01-01

    Fourier analysis has been applied to data obtained from limb viewing instruments on the Upper Atmosphere Research Satellite. A coordinate system rotation facilitates the efficient computation of Fourier transforms in the temporal and longitudinal domains. Fields such as ozone (O3), chlorine monoxide (ClO), temperature, and water vapor have been transformed by this process. The transforms have been inverted to provide maps of these quantities at selected times, providing a method of accurate time interpolation. Maps obtained by this process show evidence of both horizontal and vertical transport of important trace species such as O3 and ClO. An examination of the polar regions indicates that large-scale planetary variations are likely to play a significant role in transporting midstratospheric O3 into the polar regions. There is also evidence that downward transport occurs, providing a means of moving O3 into the polar vortex at lower altitudes. The transforms themselves show the structure and propagation characteristics of wave variations.

  18. Beyond MOS and fibers: Optical Fourier-transform Imaging Unit for Cananea Observatory (OFIUCO)

    Science.gov (United States)

    Nieto-Suárez, M. A.; Rosales-Ortega, F. F.; Castillo, E.; García, P.; Escobedo, G.; Sánchez, S. F.; González, J.; Iglesias-Páramo, J.; Mollá, M.; Chávez, M.; Bertone, E.; et al.

    2017-11-01

    Many physical processes in astronomy are still hampered by the lack of spatial and spectral resolution, and also restricted to the field-of-view (FoV) of current 2D spectroscopy instruments available worldwide. It is due to that, many of the ongoing or proposed studies are based on large-scale imaging and/or spectroscopic surveys. Under this philosophy, large aperture telescopes are dedicated to the study of intrinsically faint and/or distance objects, covering small FoVs, with high spatial resolution, while smaller telescopes are devoted to wide-field explorations. However, future astronomical surveys, should be addressed by acquiring un-biases, spatially resolved, high-quality spectroscopic information for a wide FoV. Therefore, and in order to improve the current instrumental offer in the Observatorio Astrofísico Guillermo Haro (OAGH) in Cananea, Mexico (INAOE); and to explore a possible instrument for the future Telescopio San Pedro Mártir (6.5m), we are currently integrating at INAOE an instrument prototype that will provide us with un-biased wide-field (few arcmin) spectroscopic information, and with the flexibility of operating at different spectral resolutions (R 1-20000), with a spatial resolution limited by seeing, and therefore, to be used in a wide range of astronomical problems. This instrument called OFIUCO: Optical Fourier-transform Imaging Unit for Cananea Observatory, will make use of the Fourier Transform Spectroscopic technique, which has been proved to be feasible in the optical wavelength range (350-1000 nm) with designs such as SITELLE (CFHT). We describe here the basic technical description of a Fourier transform spectrograph with important modifications from previous astronomical versions, as well as the technical advantages and weakness, and the science cases in which this instrument can be implemented.

  19. Ion-cyclotron-resonance- and Fourier-transform-ion-cyclotron-resonance spectroscopy: technology and application

    International Nuclear Information System (INIS)

    Luederwald, I.

    1977-01-01

    Instrumentation and technology of Ion-Cyclotron-Resonance and Fourier-Transform-Ion-Cyclotron-Resonance Spectroscopy are described. The method can be applied to studies of ion/molecule reactions in gas phase, to obtain thermodynamic data as gas phase acidity or basicity, proton and electron affinity, and to establish reaction mechanisms and ion structures. (orig.) [de

  20. An Image Matching Method Based on Fourier and LOG-Polar Transform

    Directory of Open Access Journals (Sweden)

    Zhijia Zhang

    2014-04-01

    Full Text Available This Traditional template matching methods are not appropriate for the situation of large angle rotation between two images in the online detection for industrial production. Aiming at this problem, Fourier transform algorithm was introduced to correct image rotation angle based on its rotatary invariance in time-frequency domain, orienting image under test in the same direction with reference image, and then match these images using matching algorithm based on log-polar transform. Compared with the current matching algorithms, experimental results show that the proposed algorithm can not only match two images with rotation of arbitrary angle, but also possess a high matching accuracy and applicability. In addition, the validity and reliability of algorithm was verified by simulated matching experiment targeting circular images.

  1. Infrared spectrometry of Venus: IR Fourier spectrometer on Venera 15 as a precursor of PFS for Venus express

    Science.gov (United States)

    Zasova, L. V.; Moroz, V. I.; Formisano, V.; Ignatiev, N. I.; Khatuntsev, I. V.

    2004-01-01

    Thermal infrared spectrometry in the range 6-40 μm with spectral resolution of 4.5-6.5 cm -1 was realized onboard of Venera 15 for the middle atmosphere of Venus investigations. The 3-D temperature and zonal wind fields ( h, ϕ, LT) in the range 55-100 km and the 3-D aerosol field ( h, ϕ, LT) in the range 55-70 km were retrieved and analyzed. The solar related waves at isobaric levels, generated by the absorbed solar energy, were investigated. In the thermal IR spectral range the, ν1, ν2 and ν3 SO 2 and the H 2O rotational (40 μm) and vibro-rotational (6.3 μm) absorption bands are observed and used for minor compounds retrieval. An advantage of the thermal infrared spectrometry method is that both the temperature and aerosol profiles, which need for retrieval of the vertical profiles of minor compounds, are evaluated from the same spectrum. The Fourier spectrometer on Venera-15 may be considered as a precursor of the Planetary Fourier Spectrometer (PI Prof. V. Formisano), which is included in the payload of the planned Venus Express mission. It has a spectral range 0.9-45 μm, separated into two channels: a short wavelength channel (SWC) in the range 0.9-5 μm and a long wavelength channel (LWC) from 6 to 45 μm, and spectral resolution of 1-2 cm -1. In the history of planetary Fourier spectrometry the PFS is a unique instrument, which possesses a short wavelength channel. A functioning of this instrument on the polar orbit with a good spatial and local time coverage will advance our knowledge in the fundamental problems of the Venus atmosphere.

  2. Beyond Fourier

    Science.gov (United States)

    Hoch, Jeffrey C.

    2017-10-01

    Non-Fourier methods of spectrum analysis are gaining traction in NMR spectroscopy, driven by their utility for processing nonuniformly sampled data. These methods afford new opportunities for optimizing experiment time, resolution, and sensitivity of multidimensional NMR experiments, but they also pose significant challenges not encountered with the discrete Fourier transform. A brief history of non-Fourier methods in NMR serves to place different approaches in context. Non-Fourier methods reflect broader trends in the growing importance of computation in NMR, and offer insights for future software development.

  3. The fractional Fourier transform as a simulation tool for lens-based X-ray microscopy

    DEFF Research Database (Denmark)

    Pedersen, Anders Filsøe; Simons, Hugh; Detlefs, Carsten

    2018-01-01

    The fractional Fourier transform (FrFT) is introduced as a tool for numerical simulations of X-ray wavefront propagation. By removing the strict sampling requirements encountered in typical Fourier optics, simulations using the FrFT can be carried out with much decreased detail, allowing...... the attenuation from the entire CRL using one or two effective apertures without loss of accuracy, greatly accelerating simulations involving CRLs. To demonstrate the applicability and accuracy of the FrFT, the imaging resolution of a CRL-based imaging system is estimated, and the FrFT approach is shown...

  4. Surface analysis by Fourier-transform infrared (FTIR) spectroscopy

    International Nuclear Information System (INIS)

    Powell, G.L.; Smyrl, N.R.; Fuller, E.L.

    1981-01-01

    A diffuse-reflectance capability for the Fourier transform infrared spectrometer at the Y-12 Plant Laboratory has been implemented. A sample cell with a 25 to 400 0 C temperature-controlled sample stage and an ultrahigh-vacuum-to-atmospheric pressure gas-handling capability has been developed. Absorbance of light from the spectrometer beam, resulting from the beam being scattered from a powder sample, can be measured. This capability of detecting molecular species on and in powders is to be used to study chemisorption on actinide and rare-earth metals, alloys, and compounds. Cell design is described along with experiments demonstrating its performance in detecting moisture absorption on uranium oxide, moisture and carbon dioxide absorption on the lithium hydride/hydroxide system, and carbon dioxide absorption on potassium borohydride. 13 figures

  5. Criteria for confirming sequence periodicity identified by Fourier transform analysis: application to GCR2, a candidate plant GPCR?

    Science.gov (United States)

    Illingworth, Christopher J R; Parkes, Kevin E; Snell, Christopher R; Mullineaux, Philip M; Reynolds, Christopher A

    2008-03-01

    Methods to determine periodicity in protein sequences are useful for inferring function. Fourier transformation is one approach but care is required to ensure the periodicity is genuine. Here we have shown that empirically-derived statistical tables can be used as a measure of significance. Genuine protein sequences data rather than randomly generated sequences were used as the statistical backdrop. The method has been applied to G-protein coupled receptor (GPCR) sequences, by Fourier transformation of hydrophobicity values, codon frequencies and the extent of over-representation of codon pairs; the latter being related to translational step times. Genuine periodicity was observed in the hydrophobicity whereas the apparent periodicity (as inferred from previously reported measures) in the translation step times was not validated statistically. GCR2 has recently been proposed as the plant GPCR receptor for the hormone abscisic acid. It has homology to the Lanthionine synthetase C-like family of proteins, an observation confirmed by fold recognition. Application of the Fourier transform algorithm to the GCR2 family revealed strongly predicted seven fold periodicity in hydrophobicity, suggesting why GCR2 has been reported to be a GPCR, despite negative indications in most transmembrane prediction algorithms. The underlying multiple sequence alignment, also required for the Fourier transform analysis of periodicity, indicated that the hydrophobic regions around the 7 GXXG motifs commence near the C-terminal end of each of the 7 inner helices of the alpha-toroid and continue to the N-terminal region of the helix. The results clearly explain why GCR2 has been understandably but erroneously predicted to be a GPCR.

  6. Suppression law of quantum states in a 3D photonic fast Fourier transform chip

    Science.gov (United States)

    Crespi, Andrea; Osellame, Roberto; Ramponi, Roberta; Bentivegna, Marco; Flamini, Fulvio; Spagnolo, Nicolò; Viggianiello, Niko; Innocenti, Luca; Mataloni, Paolo; Sciarrino, Fabio

    2016-01-01

    The identification of phenomena able to pinpoint quantum interference is attracting large interest. Indeed, a generalization of the Hong–Ou–Mandel effect valid for any number of photons and optical modes would represent an important leap ahead both from a fundamental perspective and for practical applications, such as certification of photonic quantum devices, whose computational speedup is expected to depend critically on multi-particle interference. Quantum distinctive features have been predicted for many particles injected into multimode interferometers implementing the Fourier transform over the optical modes. Here we develop a scalable approach for the implementation of the fast Fourier transform algorithm using three-dimensional photonic integrated interferometers, fabricated via femtosecond laser writing technique. We observe the suppression law for a large number of output states with four- and eight-mode optical circuits: the experimental results demonstrate genuine quantum interference between the injected photons, thus offering a powerful tool for diagnostic of photonic platforms. PMID:26843135

  7. Mass Spectrometry and Fourier Transform Infrared Spectroscopy for Analysis of Biological Materials

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Timothy J. [Iowa State Univ., Ames, IA (United States)

    2014-12-01

    Time-of-flight mass spectrometry along with statistical analysis was utilized to study metabolic profiles among rats fed resistant starch (RS) diets. Fischer 344 rats were fed four starch diets consisting of 55% (w/w, dbs) starch. A control starch diet consisting of corn starch was compared against three RS diets. The RS diets were high-amylose corn starch (HA7), HA7 chemically modified with octenyl succinic anhydride, and stearic-acid-complexed HA7 starch. A subgroup received antibiotic treatment to determine if perturbations in the gut microbiome were long lasting. A second subgroup was treated with azoxymethane (AOM), a carcinogen. At the end of the eight week study, cecal and distal-colon contents samples were collected from the sacrificed rats. Metabolites were extracted from cecal and distal colon samples into acetonitrile. The extracts were then analyzed on an accurate-mass time-of-flight mass spectrometer to obtain their metabolic profile. The data were analyzed using partial least-squares discriminant analysis (PLS-DA). The PLS-DA analysis utilized a training set and verification set to classify samples within diet and treatment groups. PLS-DA could reliably differentiate the diet treatments for both cecal and distal colon samples. The PLS-DA analyses of the antibiotic and no antibiotic treated subgroups were well classified for cecal samples and modestly separated for distal-colon samples. PLS-DA analysis had limited success separating distal colon samples for rats given AOM from those not treated; the cecal samples from AOM had very poor classification. Mass spectrometry profiling coupled with PLS-DA can readily classify metabolite differences among rats given RS diets.

  8. A Fourier transform method for Vsin i estimations under nonlinear Limb-Darkening laws

    Energy Technology Data Exchange (ETDEWEB)

    Levenhagen, R. S., E-mail: ronaldo.levenhagen@gmail.com [Universidade Federal de São Paulo, Depto. Ciências Exatas e da Terra, Rua Prof. Arthur Riedel, 275, Jd. Eldorado, CEP 09972-270 Diadema, SP (Brazil)

    2014-12-10

    Star rotation offers us a large horizon for the study of many important physical issues pertaining to stellar evolution. Currently, four methods are widely used to infer rotation velocities, namely those related to line width calibrations, on the fitting of synthetic spectra, interferometry, and on Fourier transforms (FTs) of line profiles. Almost all of the estimations of stellar projected rotation velocities using the Fourier method in the literature have been addressed with the use of linear limb-darkening (LD) approximations during the evaluation of rotation profiles and their cosine FTs, which in certain cases, lead to discrepant velocity estimates. In this work, we introduce new mathematical expressions of rotation profiles and their Fourier cosine transforms assuming three nonlinear LD laws—quadratic, square-root, and logarithmic—and study their applications with and without gravity-darkening (GD) and geometrical flattening (GF) effects. Through an analysis of He I models in the visible range accounting for both limb and GD, we find out that, for classical models without rotationally driven effects, all the Vsin i values are too close to each other. On the other hand, taking into account GD and GF, the Vsin i obtained with the linear law result in Vsin i values that are systematically smaller than those obtained with the other laws. As a rule of thumb, we apply these expressions to the FT method to evaluate the projected rotation velocity of the emission B-type star Achernar (α Eri).

  9. Beyond Fourier.

    Science.gov (United States)

    Hoch, Jeffrey C

    2017-10-01

    Non-Fourier methods of spectrum analysis are gaining traction in NMR spectroscopy, driven by their utility for processing nonuniformly sampled data. These methods afford new opportunities for optimizing experiment time, resolution, and sensitivity of multidimensional NMR experiments, but they also pose significant challenges not encountered with the discrete Fourier transform. A brief history of non-Fourier methods in NMR serves to place different approaches in context. Non-Fourier methods reflect broader trends in the growing importance of computation in NMR, and offer insights for future software development. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Quantum copying and simplification of the quantum Fourier transform

    Science.gov (United States)

    Niu, Chi-Sheng

    Theoretical studies of quantum computation and quantum information theory are presented in this thesis. Three topics are considered: simplification of the quantum Fourier transform in Shor's algorithm, optimal eavesdropping in the BB84 quantum cryptographic protocol, and quantum copying of one qubit. The quantum Fourier transform preceding the final measurement in Shor's algorithm is simplified by replacing a network of quantum gates with one that has fewer and simpler gates controlled by classical signals. This simplification results from an analysis of the network using the consistent history approach to quantum mechanics. The optimal amount of information which an eavesdropper can gain, for a given level of noise in the communication channel, is worked out for the BB84 quantum cryptographic protocol. The optimal eavesdropping strategy is expressed in terms of various quantum networks. A consistent history analysis of these networks using two conjugate quantum bases shows how the information gain in one basis influences the noise level in the conjugate basis. The no-cloning property of quantum systems, which is the physics behind quantum cryptography, is studied by considering copying machines that generate two imperfect copies of one qubit. The best qualities these copies can have are worked out with the help of the Bloch sphere representation for one qubit, and a quantum network is worked out for an optimal copying machine. If the copying machine does not have additional ancillary qubits, the copying process can be viewed using a 2-dimensional subspace in a product space of two qubits. A special representation of such a two-dimensional subspace makes possible a complete characterization of this type of copying. This characterization in turn leads to simplified eavesdropping strategies in the BB84 and the B92 quantum cryptographic protocols.

  11. A New Form of the Spherical Expansion of Zonal Functions and Fourier Transforms of SO(d-Finite Functions

    Directory of Open Access Journals (Sweden)

    Agata Bezubik

    2006-03-01

    Full Text Available This paper presents recent results obtained by the authors (partly in collaboration with A. Dabrowska concerning expansions of zonal functions on Euclidean spheres into spherical harmonics and some applications of such expansions for problems involving Fourier transforms of functions with rotational symmetry. The method used to derive the expansion formula is based entirely on differential methods and completely avoids the use of various integral identities commonly used in this context. Some new identities for the Fourier transform are derived and as a byproduct seemingly new recurrence relations for the classical Bessel functions are obtained.

  12. Graded-index fibers, Wigner-distribution functions, and the fractional Fourier transform.

    Science.gov (United States)

    Mendlovic, D; Ozaktas, H M; Lohmann, A W

    1994-09-10

    Two definitions of a fractional Fourier transform have been proposed previously. One is based on the propagation of a wave field through a graded-index medium, and the other is based on rotating a function's Wigner distribution. It is shown that both definitions are equivalent. An important result of this equivalency is that the Wigner distribution of a wave field rotates as the wave field propagates through a quadratic graded-index medium. The relation with ray-optics phase space is discussed.

  13. Seasonal variations in the profile of main phospholipids in Mytilus galloprovincialis mussels: A study by hydrophilic interaction liquid chromatography-electrospray ionization Fourier transform mass spectrometry.

    Science.gov (United States)

    Facchini, Laura; Losito, Ilario; Cataldi, Tommaso R I; Palmisano, Francesco

    2018-01-01

    A systematic characterization of phosphatidylcholines and phosphatidylethanolamines in mussels of sp Mytilus galloprovincialis was performed by high-efficiency hydrophilic interaction liquid chromatography combined with electrospray ionization and Fourier transform mass spectrometry (FTMS), based on a quadrupole-Orbitrap hybrid spectrometer. The FTMS/MS experiments under high collisional energy dissociation conditions, complemented by low-energy collisionally induced dissociation MS n (n = 2,3) experiments, performed in a linear ion trap mass spectrometer, were exploited for structural elucidation purposes. The described approach led to an unprecedented characterization of the mussel phospholipidome, with 185 phosphatidylcholines and 131 phosphatidylethanolamines species recognized, distributed among diacylic, plasmanylic, and plasmenylic forms. This was the starting point for the evaluation of the effects of season (in particular, of sea temperature) on the profile of those phospholipids. To this aim, a set of mussel samples retrieved from commercial sources in different periods of the year was considered. Principal component analysis revealed a clear separation between samples collected in periods characterized by cold, intermediate, or warm sea temperatures, respectively. In particular, an enrichment in phospholipids containing unsaturated side chains was observed in mussels collected from cold seawaters (winter-early spring), thus confirming the general model previously elaborated to explain the adaptation of marine invertebrates, including some bivalve molluscs, to low temperatures. On the other hand, relevant levels of plasma(e)nylic and acylic phospholipids bearing either saturated or non-methylene-interrupted side chains were found in mussels collected in warm seawaters (typical of summer and early autumn, at Italian latitudes). This finding opened interesting perspectives towards the development of strategies able to prevent global warming-related mussel

  14. Rotation-type input-output relationships for Wigner distribution moments in fractional Fourier transform systems

    NARCIS (Netherlands)

    Bastiaans, M.J.; Alieva, T.

    2002-01-01

    It is shown how all global Wigner distribution moments of arbitrary order in the output plane of a (generally anamorphic) two-dimensional fractional Fourier transform system can be expressed in terms of the moments in the input plane. This general input-output relationship is then broken down into a

  15. Fe- and Cu-complex formation with artificial ligands investigated by ultra-high resolution Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS: Implications for natural metal-organic complex studies

    Directory of Open Access Journals (Sweden)

    Hannelore Waska

    2016-07-01

    Full Text Available In recent years, electrospray-ionization mass spectrometry (ESI-MS has been increasingly used to complement the bulk determination of metal-ligand equilibria, for example via competitive ligand exchange-adsorptive cathodic stripping voltammetry (CLE-ACSV. However, ESI-MS speciation analyses may be impacted by instrumental artefacts such as reduction reactions, fragmentation, and adduct formation at the ESI source, changes in the ionization efficiencies of the detected species in relation to sample matrix, and peak overlaps in response to increasing sample complexity. In our study, equilibria of the known artificial ligands citrate, ethylenediaminetetraacetic acid (EDTA, 1-nitroso-2-naphthol (NN, and salicylaldoxime (SA with iron (Fe and copper (Cu were investigated by ultra-high resolution ESI-MS, Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS, under a variety of sample matrix and ionization settings. The acquired mass spectra were compared with metal-ligand equilibrium data from the literature as well as an adapted speciation model. Overall, the mass spectra produced representative species mentioned in previous reports and predicted by the speciation calculations, such as Fe(Cit, Cu(Cit2, Fe(EDTA, Cu(EDTA, Fe(NN3, and Cu(SA2. The analyses furthermore revealed new species which had been hypothesized but not measured directly using other methods, for example ternary complexes of citrate with Fe and Cu, Cu(SA monomers, and the dimer Fe(SA2. Finally, parallel measurements of a Cu+SA calibration series and a Cu+SA+EDTA competition series indicated that FT-ICR-MS can produce linear responses and low detection limits analogous to those of ACSV. We propose that ultra-high resolution FT-ICR-MS can be used as a representative tool to study interactions of trace metals with artificial as well as natural, unknown ligands at the molecular level.

  16. Non-rigid registration of tomographic images with Fourier transforms

    International Nuclear Information System (INIS)

    Osorio, Ar; Isoardi, Ra; Mato, G

    2007-01-01

    Spatial image registration of deformable body parts such as thorax and abdomen has important medical applications, but at the same time, it represents an important computational challenge. In this work we propose an automatic algorithm to perform non-rigid registration of tomographic images using a non-rigid model based on Fourier transforms. As a measure of similarity, we use the correlation coefficient, finding that the optimal order of the transformation is n = 3 (36 parameters). We apply this method to a digital phantom and to 7 pairs of patient images corresponding to clinical CT scans. The preliminary results indicate a fairly good agreement according to medical experts, with an average registration error of 2 mm for the case of clinical images. For 2D images (dimensions 512x512), the average running time for the algorithm is 15 seconds using a standard personal computer. Summarizing, we find that intra-modality registration of the abdomen can be achieved with acceptable accuracy for slight deformations and can be extended to 3D with a reasonable execution time

  17. Combination of electrospray ionization, atmospheric pressure photoionization and laser desorption ionization Fourier transform ion cyclotronic resonance mass spectrometry for the investigation of complex mixtures – Application to the petroleomic analysis of bio-oils

    Energy Technology Data Exchange (ETDEWEB)

    Hertzog, Jasmine [LCP-A2MC, FR 2843 Institut Jean Barriol de Chimie et Physique Moléculaires et Biomoléculaires, FR 3624 Réseau National de Spectrométrie de Masse FT-ICR à très haut champ, Université de Lorraine, ICPM, 1 boulevard Arago, 57078 Metz Cedex 03 (France); Carré, Vincent, E-mail: vincent.carre@univ-lorraine.fr [LCP-A2MC, FR 2843 Institut Jean Barriol de Chimie et Physique Moléculaires et Biomoléculaires, FR 3624 Réseau National de Spectrométrie de Masse FT-ICR à très haut champ, Université de Lorraine, ICPM, 1 boulevard Arago, 57078 Metz Cedex 03 (France); Le Brech, Yann [LRGP, CNRS, Université de Lorraine, ENSIC, 1, Rue Grandville, 54000 Nancy (France); Mackay, Colin Logan [SIRCAMS, School of Chemistry, University of Edinburgh, Edinburgh, EH9 3FJ, Scotland (United Kingdom); Dufour, Anthony [LRGP, CNRS, Université de Lorraine, ENSIC, 1, Rue Grandville, 54000 Nancy (France); Mašek, Ondřej [UK Biochar Research Center, School of Geosciences, University of Edinburgh, Kings Buildings, Edinburgh, EH9 3JN (United Kingdom); and others

    2017-05-29

    The comprehensive description of complex mixtures such as bio-oils is required to understand and improve the different processes involved during biological, environmental or industrial operation. In this context, we have to consider how different ionization sources can improve a non-targeted approach. Thus, the Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) has been coupled to electrospray ionization (ESI), laser desorption ionization (LDI) and atmospheric pressure photoionization (APPI) to characterize an oak pyrolysis bio-oil. Close to 90% of the all 4500 compound formulae has been attributed to C{sub x}H{sub y}O{sub z} with similar oxygen class compound distribution. Nevertheless, their relative abundance in respect with their double bound equivalent (DBE) value has evidenced significant differences depending on the ion source used. ESI has allowed compounds with low DBE but more oxygen atoms to be ionized. APPI has demonstrated the efficient ionization of less polar compounds (high DBE values and less oxygen atoms). The LDI behavior of bio-oils has been considered intermediate in terms of DBE and oxygen amounts but it has also been demonstrated that a significant part of the features are specifically detected by this ionization method. Thus, the complementarity of three different ionization sources has been successfully demonstrated for the exhaustive characterization by petroleomic approach of a complex mixture. - Highlights: • Non-targeted mass spectrometry by combining electrospray ionization, atmospheric pressure photoionization and laser/desorption ionization. • Exhaustive description of pyrolytic bio-oil components. • Distinction of sugaric derivatives, lignin derivatives and lipids contained in a woody-based pyrolytic bio-oil.

  18. Far-infrared Fourier Transform Spectroscopy Measurements of Mn12-acetate.

    Science.gov (United States)

    Tu, Jiufeng; Suzuki, Yoko; Mertes, K. M.; Sarachik, M. P.; Agladze, N. I.; Sievers, A. J.; Rumberger, E. M.; Hendrickson, D. N.; Christou, G.

    2004-03-01

    The transmission spectra of both powder samples and assemblies of single crystals of Mn_12-acetate were measured in the far infrared region (2.0 - 20 cm-1) using a Fourier transform technique. The energies of the observed aborption lines agree with those obtained by Mukhin et al. [1] using the backwards wave oscillator technique. The temperature dependence of the aborption lines, as well as the presence of additional absorption lines, will be discussed. [1] A. A. Mukhin, V. D. Travkin, A. K. Zvesdin, A. Caneschi, D. Gatteschi and R. Sessoli, Physica B 284-288 (2000) 1221-1222

  19. The deconvolution of Doppler-broadened positron annihilation measurements using fast Fourier transforms and power spectral analysis

    International Nuclear Information System (INIS)

    Schaffer, J.P.; Shaughnessy, E.J.; Jones, P.L.

    1984-01-01

    A deconvolution procedure which corrects Doppler-broadened positron annihilation spectra for instrument resolution is described. The method employs fast Fourier transforms, is model independent, and does not require iteration. The mathematical difficulties associated with the incorrectly posed first order Fredholm integral equation are overcome by using power spectral analysis to select a limited number of low frequency Fourier coefficients. The FFT/power spectrum method is then demonstrated for an irradiated high purity single crystal sapphire sample. (orig.)

  20. Application of the one-dimensional Fourier transform for tracking moving objects in noisy environments

    Science.gov (United States)

    Rajala, S. A.; Riddle, A. N.; Snyder, W. E.

    1983-01-01

    In Riddle and Rajala (1981), an algorithm was presented which operates on an image sequence to identify all sets of pixels having the same velocity. The algorithm operates by performing a transformation in which all pixels with the same two-dimensional velocity map to a peak in a transform space. The transform can be decomposed into applications of the one-dimensional Fourier transform and therefore can gain from the computational advantages of the FFT. The aim of this paper is the concern with the fundamental limitations of that algorithm, particularly as relates to its sensitivity to image-disturbing parameters as noise, jitter, and clutter. A modification to the algorithm is then proposed which increases its robustness in the presence of these disturbances.